Absorber tube displacement in parabolic trough collectors – A review and presentation of an airborne measurement approach

Parabolic trough collectors for concentrating solar sower plants are large scale optical devices with demanding requirements on optical and mechanical properties. Accurate mirror shape and absorber tube alignment are necessary to harness solar radiation with high efficiency. There are several methods to assess the shape of the mirror surface, yet there exist few approaches to effectively measure the Position of the absorber tube. This paper provides a comprehensive overview on causes and effects of absorber tube displacement and on state of the art measurement techniques. A new approach on fully automated airborne absorber tube position measurement for parabolic trough collectors is presented, which outperforms existing methods concerning speed, spatial resolution, and level of automation, thereby achieving an accuracy of about 1.5 mm in vertical and lateral direction

Air-Borne Shape Measurement of Parabolic Trough Collector Fields

The optical and thermal efficiency of parabolic trough collector solar fields is dependent on the performance and assembly accuracy of its components such as the concentrator and absorber. For the purpose of optical inspection/approval, yield analysis, localization of low performing areas, and optimization of the solar field, it is essential to create a complete view of the optical properties of the field. Existing optical measurement tools are based on ground based cameras, facing restriction concerning speed, volume and automation. QFly is an airborne qualification system which provides holistic and accurate information on geometrical, optical, and thermal properties of the entire solar field. It consists of an unmanned aerial vehicle, cameras and related software for flight path planning, data acquisition and evaluation. This article presents recent advances of the QFly measurement system and proposes a methodology on holistic qualification of the complete solar field with minimum impact on plant Operation

Auszug aus der Richtlinie des Akademischen Senats für die Vergabe der Bruno Snell-Plakette für beispielhaftes Wirken in Wissenschaft und Gesellschaft vom 12. Juni 1997

Dieser Band vereint Reden, die anlässlich der Verleihung der Bruno Snell-Plakette an den Historiker Prof. Fritz Stern gehalten wurden.This volume brings together speeches made on the occasion of the presentation of the Bruno Snell plaque to the historian Prof. Fritz Stern

TRAIL and Taurolidine induce apoptosis and decrease proliferation in human fibrosarcoma

<p>Abstract</p> <p>Background</p> <p>Disseminated soft tissue sarcoma still represents a therapeutic dilemma because effective cytostatics are missing. Therefore we tested TRAIL and Tarolidine (TRD), two substances with apoptogenic properties on human fibrosarcoma (HT1080).</p> <p>Methods</p> <p>Viability, apoptosis and necrosis were visualized by TUNEL-Assay and quantitated by FACS analysis (Propidiumiodide/AnnexinV staining). Gene expression was analysed by RNA-Microarray and the results validated for selected genes by rtPCR. Protein level changes were documented by Western Blot analysis. NFKB activity was analysed by ELISA and proliferation assays (BrdU) were performed.</p> <p>Results and discussion</p> <p>The single substances TRAIL and TRD induced apoptotic cell death and decreased proliferation in HT1080 cells significantly. Gene expression of several genes related to apoptotic pathways (TRAIL: <it>ARHGDIA</it>, <it>NFKBIA</it>, <it>TNFAIP3</it>; TRD: <it>HSPA1A/B</it>, <it>NFKBIA</it>, <it>GADD45A</it>, <it>SGK</it>, <it>JUN</it>, <it>MAP3K14</it>) was changed. The combination of TRD and TRAIL significantly increased apoptotic cell death compared to the single substances and lead to expression changes in a variety of genes (<it>HSPA1A/B</it>, <it>NFKBIA</it>, <it>PPP1R15A</it>, <it>GADD45A</it>, <it>AXL</it>, <it>SGK</it>, <it>DUSP1</it>, <it>JUN</it>, <it>IRF1</it>, <it>MYC</it>, <it>BAG5</it>, <it>BIRC3</it>). NFKB activity assay revealed an antipodal regulation of the several subunits of NFKB by TRD and TRD+TRAIL compared to TRAIL alone.</p> <p>Conclusion</p> <p>TRD and TRAIL are effective to induce apoptosis and decrease proliferation in human fibrosarcoma. A variety of genes seems to be involved, pointing to the NFKB pathway as key regulator in TRD/TRAIL-mediated apoptosis.</p

Airtime for newcomers. Radio for Migrants in the United Kingdom and West Germany, 1960s–1980s

This article explores the British and West German public service radio’s abilities to reflect on and to address the specific needs and expectations of migrant groups in their programmes between the 1960s and 1980s. Mechanisms of social inclusion and exclusion alike can be investigated here. Empirically, it is based on comparisons of radio broadcasts on and for different immigrant communities, produced by BBC Radio Leicester on/for the post-war Asian migrants in England and by West German public service broadcasting on/for ‘Gastarbeiter’ (foreign workers) as well as for ‘Spätaussiedler’ (German repatriates from East Europe). Radio is studied as an agent of identity management and citizenship education. Not only did radio talk about migrants and migration to introduce these topics and the newcomers to the local population. It also offered airtime to selected migrant communities to cater for their needs and interests as well as to facilitate their difficulties of adjusting to an unfamiliar environment

Airborne Shape Measurement of Parabolic Trough Collector Fields

As the optical efficiency of the solar field has a high impact on the overall plant performance, qualification methods determining the geometrical accuracy of solar concentrator systems have gained high importance. However, it has not been possible yet to measure the geometrical accuracy of an entire solar field, resolving the relevant single characteristics like local mirror slope deviations, panel alignment and gravitational deformation. This paper describes the development and assessment of a measurement technique for the qualification of parabolic troughs based on the distant observer method called TARMES (Trough Absorber Reflection Measurement System). Instead of a stationary camera at ground level taking pictures of a turning collector, the new approach called QFly makes use of an airborne camera vehicle which allows a completely automated and fast measurement of all collectors under relevant operating conditions. The new approach was validated against a stationary TARMES and photogrammetric measurement to compare the deviations between the different methods and with the expectations of an uncertainty analysis. The absolute measurement uncertainty of QFly on a module level is around ± 0.1 milliradians