Vanishing tilt-to-length coupling for a singular case in two-beam laser interferometers with Gaussian beams

The omnipresent tilt-to-length coupling in two-beam laser interferometers, frequently a nuisance in precision measurements, vanishes for the singular case of two beams with identical parameters and complete detection of both beams without clipping. This effect has been observed numerically and is explained in this manuscript by the cancellation of two very different effects of equal magnitude and opposite sign. This paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: [http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-54-5-1010]. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law

A brief comparison of optical pathlength difference and various definitions for the interferometric phase

To this paper we discuss that the phase readout in low noise laser interferometers can significantly deviate from the underlying optical pathlength difference (OPD). The cross coupling of beam tilt to the interferometric phase readout is compared to the OPD. For such a system it is shown that the amount of tilt to phase readout coupling depends strongly on the involved beams and their parameters, as well as on the detector properties and the precise definition of the phase. The unique single element photodiode phase is therefore compared to three common phase definitions for quadrant diodes. It is shown that neither phase definition globally shows the least amount of cross coupling of angular itDeutsches Zentrum für Luft- und Raumfahrt (DLR)/No 50 OQ 130

Nocturnal nitrogen oxides at a rural mountain-site in south-western Germany

A new, two-channel instrument for simultaneous NO3 and N2O5 monitoring was used to make the first comprehensive set of nocturnal NOx measurements (NO, NO2, NO3 and N2O5) at the Taunus Observatory, a rural mountain site (Kleiner Feldberg) in South-western Germany. In May 2008, NO3 and N2O5 mixing ratios were well above the instrumental detection limit (a few ppt) on all nights of the campaign and were characterised by large variability. The concentrations of NO3, N2O5 and NO2 were consistent with the equilibrium constant, K2, defining the rates of formation and thermal dissociation of N2O5. A steady-state lifetime analysis is consistent with the loss of nocturnal NOx being dominated by the reaction of NO3 with volatile organic compounds in this forested region, with N2O5 uptake to aerosols of secondary importance. Analysis of a limited dataset obtained at high relative humidity indicated that the loss of N2O5 by reaction with water vapour is less efficient (>factor 3) than derived using laboratory kinetic data. The fraction of NOx present as NO3 and N2O5 reached ~20% on some nights, with night-time losses of NOx competing with daytime losses

Efficiency Improvement of a Constant Pressure System using an Intermediate Pressure Line

The paper introduces a new hydraulic system based on a constant pressure system with the aim to increase the efficiency of actuation of hydraulic cylinders in mobile machines. Using a third pressure level located between high pressure and tank pressure called intermediate pressure the system enables additional pressure potentials from high pressure to intermediate pressure and from intermediate pressure to tank pressure. This reduces throttle losses at hydraulic cylinders when driven at low or medium loads. An accumulator connected to the intermediate pressure line is being charged or discharged in function of which pressure potential is currently used. Using the example of a typical duty cycle of a wheel loader the paper describes how the accumulator can be applied in order to reach best efficiency results for the new system and it reveals a theoretical efficiency improvement of 20% compared to a conventional Load Sensing system. Furthermore it proposes an online control strategy using Model Predictive Control with an optimization algorithm created with the Dynamic Programming method

Erkenntnisse und Empfehlungen aus der Begleitforschung einer Bildungslandschaft

Im Ruhrgebiet haben sich in den letzten sechs Jahrzehnten strukturelle Veränderungen wie in kaum einer anderen Region Deutschlands vollzogen. Zwar ist im Hinblick auf den Strukturwandel manches erreicht worden, dennoch gibt es bleibende ökonomische und soziale Problemlagen: Der Verlust von Arbeitsplätzen in der Montanindustrie konnte nicht kompensiert werden, zudem hat die Region einen deutlichen Bevölkerungsverlust erlitten und ist durch eine starke soziale Polarisierung gekennzeichnet. Auch im Bildungsbereich spiegeln sich die sozialstrukturellen Umwälzungen und Herausforderungen deutlich wider. So ist die Region etwa mit einem hohen Bedarf an Sprachförderung konfrontiert. Generell nimmt die Metropole Ruhr durch ihr vergleichsweise geringes Bildungsniveau einen Sonderstatus ein. So lassen sich starke Unterschiede im Bildungsniveau von Personen mit und ohne Zuwanderungsgeschichte feststellen. Bei Kindern im Vorschulalter weisen etwa 20% unzureichende Deutschkenntnisse auf, davon kommt ein Großteil aus Familien mit geringen Bildungsressourcen. Obwohl sich in der Metropole Ruhr eine große Hochschullandschaft mit steigenden Studierendenzahlen angesiedelt hat, sind Personen mit Zuwanderungsgeschichte unter den Studienberechtigten nach wie vor deutlich unterrepräsentiert. Es zeigt sich außerdem, dass sich deutlich weniger Menschen mit Hochschulberechtigung in der Region Ruhr für ein Studium entscheiden, als dies im gesamtdeutschen Vergleich der Fall ist. Das Forschungskonsortium des Bildungsberichts Ruhr hat im Rahmen des Berichts Herausforderungen benannt und Empfehlungen formuliert, um dem Bildungsungleichgewicht in der Metropole Ruhr entgegenzuwirken. Zu den übergreifenden Empfehlungen zählen dabei die Etablierung einer Bildungsregion Metropole Ruhr, die sich als Verantwortungsraum betrachtet, in dem die lokalen Akteurinnen und Akteure durch Austausch, Absprachen und Kooperationen gemeinsam Lösungen entwickeln und die Kinder, Jugendlichen und jungen Erwachsenen der Region ganzheitlich und über die gesamte Bildungsbiographie hinweg begleiten. Die Wissenschaftlerinnen und Wissenschaftler empfehlen außerdem die Entwicklung und Implementierung eines regionalen Bildungsmonitorings, das übergreifend Daten erhebt, aufbereitet und analysiert, um Entwicklungen in den Kommunen der Metropole Ruhr analysieren und Handlungsbedarfe identifizieren zu können. Auch diese Daten sollen die gesamte Bildungsbiographie bis hin zur Hochschule umfassen. Um den Herausforderungen der Region zu begegnen, wurde 2012 von der Stiftung Mercator (Initiative und Förderung), der Landesregierung Nordrhein-Westfalen, den Kommunen Dortmund, Essen, Gelsenkirchen, Herten und Mülheim an der Ruhr, den Hochschulen Ruhr-Universität Bochum, Fachhochschule Dortmund, Technischen Universität Dortmund, Universität Duisburg-Essen und Westfälische Hochschule die gemeinsame Bildungsinitiative RuhrFutur gegründet, an der mittlerweile auch der Regionalverband Ruhr – als übergreifende kommunale Organisation aller Städte und Kreise des Ruhrgebiets – aktiv als Partner mitwirkt

Sub-system mechanical design for an eLISA optical bench

We present the design and development status of the opto-mechanical sub-systems that will be used in an experimental demonstration of imaging systems for eLISA. An optical bench test bed design incorporates a Zerodur® baseplate with lenses, photodetectors, and other opto-mechanics that must be both adjustable - with an accuracy of a few micrometers - and stable over a 0 to 40°C temperature range. The alignment of a multi-lens imaging system and the characterisation of the system in multiple degrees of freedom is particularly challenging. We describe the mechanical design of the precision mechanisms, including thermally stable flexure-based optical mounts and complex multi-lens, multi-axis adjuster mechanisms, and update on the integration of the mechanisms on the optical bench

Full length interleukin 33 aggravates radiation-induced skin reaction

The interleukin (IL)-1 family member IL-33 has been described as intracellular alarmin with broad roles in wound healing, skin inflammation but also autoimmunity. Its dichotomy between full length (fl) IL-33 and the mature (m) form of IL-33 and its release by necrosis is still not fully understood. Here, we compare functional consequences of both forms in the skin in vivo, and therefore generated two lines of transgenic mice which selectively overexpress mmIL-33 and flmIL-33 in basal keratinocytes. Transgene mRNA was expressed at high level in skin of both lines but not in organs due to the specific K14 promoter. We could demonstrate that transgenic overexpression of mmIL-33 in murine keratinocytes leads to a spontaneous skin inflammation as opposed to flmIL-33. K14-mmIL-33 mice synthesize and secrete high amounts of mmIL-33 along with massive cutaneous manifestations, like increased epidermis and dermis thickness, infiltration of mast cells in the epidermis and dermis layers and marked hyperkeratosis. Using skin inflammation models such as IL-23 administration, imiquimod treatment, or mechanical irritation did not lead to exacerbated inflammation in the K14-flmIL-33 strain. As radiation induces a strong dermatitis due to apoptosis and necrosis, we determined the effect of fractionated radiation (12 Gy, 4 times). In comparison to wild-type mice, an increase in ear thickness in flmIL-33 transgenic mice was observed 25 days after irradiation. Macroscopic examination showed more severe skin symptoms in irradiated ears compared to controls. In summary, secreted mmIL-33 itself has a potent capacity in skin inflammation whereas fl IL-33 is limited due to its intracellular retention. During tissue damage, fl IL-33 exacerbated radiation-induced skin reaction

A two-channel, Thermal Dissociation Cavity-Ringdown Spectrometer for the detection of ambient NO2, RO2NO2 and RONO2

Creative Commons Attribution License 3.0We describe a thermal dissociation cavity ring-down spectrometer (TD-CRDS) for measurement of ambient NO2, total peroxy nitrates (ΣPNs) and total alkyl nitrates (ΣANs). The spectrometer has two separate cavities operating at  ∼  405.2 and 408.5 nm. One cavity (reference) samples NO2 continuously from an inlet at ambient temperature, the other samples sequentially from an inlet at 473 K in which PNs are converted to NO2 or from an inlet at 723 K in which both PNs and ANs are converted to NO2, difference signals being used to derive mixing ratios of ΣPNs and ΣANs. We describe an extensive set of laboratory experiments and numerical simulations to characterise the fate of organic radicals in the hot inlets and cavity and derive correction factors to account for the bias resulting from the interaction of peroxy radicals with ambient NO and NO2. Finally, we present the first measurements and comparison with other instruments during a field campaign, outline the limitations of the present instrument and provide an outlook for future improvements.Publication funded by the Max Planck Societ

The High-Density Ionized Gas in the Central Parsecs of the Galaxy

We report the results from observations of H30$\alpha$ line emission in Sgr A West with the Submillimeter Array at a resolution of 2\arcsec and a field of view of about 40\arcsec. The H30$\alpha$ line is sensitive to the high-density ionized gas in the minispiral structure. We compare the velocity field obtained from H30$\alpha$ line emission to a Keplerian model, and our results suggest that the supermassive black hole at Sgr A* dominates the dynamics of the ionized gas. However, we also detect significant deviations from the Keplerian motion, which show that the impact of strong stellar winds from the massive stars along the ionized flows and the interaction between Northern and Eastern arms play significant roles in the local gas dynamics.Comment: 4 pages, 2 figure