Bau auf! Kreislaufgerechte Architektur in der Lehre

Traditionell verwendete Ressourcen im Bauwesen wie Sande, Kiese, Erze, Kupfer oder Zink, werden durch einen nie dagewesenen Raubbau seit dem ausgehenden 19. Jahrhundert nur noch wenige Jahre in der Erdkruste für Industrien mit vertretbaren Abbauaufwand zur Verfügung stehen. Das Forschungsprojekt desBundesministeriums für Wirtschaft und Technologie stellt bereits 2005 das dramatische Reserven-zu-Produktion-Verhältnis von Basismetallrohstoffen dar.1Allein durch einen Paradigmenwechsel im Umgang mit Ressourcen ist ein angemessener und humanitärer Lebensstandard für jeden Menschen unserer stetig wachsenden Erdbevölkerung realisierbar. Nur ein konsequent kreislaufbasiertes System garantiert, dass auch nachfolgende Generationen essentielle Ressourcen weiterhin und unendlich nutzen können. Die neuen digitalen Technologien bilden die zweite wichtige Säule für eine zukunftsfähige Bauindustrie. Firmen wie WASP drucken Häuser aus Strohlehm und sehen diese Technologie als Chance für weniger entwickelte Regionen der Welt ihre traditionellen Materialien aus der „altmodisch“- Ecke zu holen. So wird die Frage der Modernität nicht mehr am Material festgemacht, sondern an der Frage der Konstruktion undFertigung. Auch in westlichen Regionen nimmt die Frage der digitalen Fabrikation an Fahrt auf. DUS Architects hatbereits 2016 eine aus Biokunststoff gedruckte Fassade fertiggestellt.2 Barack Obama, ein prominenter Besucher der Baustelle, bezeichnete schon 2013 den 3D-Druck als die Technologie, welche die Art und Weise der Produktion in fast allen Industriezweigen revolutionieren wird.3Ein sich komplett neu entwickelndes Feld wird die Verwaltung der Daten zu den neu entstehenden Stoffströmen sein. Wir erleben eine Revolution des traditionellen Kadasterwesens, in dem vorhandene Materiallager mit den entsprechenden Materialdaten dokumentiert und verwaltet werden müssen. Architekten und Ingenieure müssen zukünftig für immer mehr Menschen mit weniger und besser eingesetztem Material kreislaufgerecht bauen. Wir, als Lehrende an der Fakultät Architektur des KIT Karlsruhe, haben die Aufgabe unsere Studierenden für die zentralen Themen der Bauindustrie zu sensibilisieren und für deren Anforderungen auszubilden. Auf den folgenden Seiten liegt der Fokus deshalb nach der Beschreibung der angeführten Problematik undmöglicher Lösungsansätze, auf dem Forschungsseminar „Bau auf!“ des Fachgebiets Nachhaltiges Bauen. Durch experimentelle Materialforschung in Verbindung mit dem 3D-Druck soll den Studierenden die noch neue Technologie in höherem Maße zugänglich gemacht werden. Dabei sehen wir uns in der Verantwortung eine materialgerechte Architektur auf Basis nachhaltiger Grundsätze bereits im Studium zu etablieren und entsprechend im Curriculum zu verankern

Is the Sun Lighter than the Earth? Isotopic CO in the Photosphere, Viewed through the Lens of 3D Spectrum Synthesis

We consider the formation of solar infrared (2-6 micron) rovibrational bands of carbon monoxide (CO) in CO5BOLD 3D convection models, with the aim to refine abundances of the heavy isotopes of carbon (13C) and oxygen (18O,17O), to compare with direct capture measurements of solar wind light ions by the Genesis Discovery Mission. We find that previous, mainly 1D, analyses were systematically biased toward lower isotopic ratios (e.g., R23= 12C/13C), suggesting an isotopically "heavy" Sun contrary to accepted fractionation processes thought to have operated in the primitive solar nebula. The new 3D ratios for 13C and 18O are: R23= 91.4 +/- 1.3 (Rsun= 89.2); and R68= 511 +/- 10 (Rsun= 499), where the uncertainties are 1 sigma and "optimistic." We also obtained R67= 2738 +/- 118 (Rsun= 2632), but we caution that the observed 12C17O features are extremely weak. The new solar ratios for the oxygen isotopes fall between the terrestrial values and those reported by Genesis (R68= 530, R6= 2798), although including both within 2 sigma error flags, and go in the direction favoring recent theories for the oxygen isotope composition of Ca-Al inclusions (CAI) in primitive meteorites. While not a major focus of this work, we derive an oxygen abundance of 603 +/- 9 ppm (relative to hydrogen; 8.78 on the logarithmic H= 12 scale). That the Sun likely is lighter than the Earth, isotopically speaking, removes the necessity to invoke exotic fractionation processes during the early construction of the inner solar system

Influence of the Ambient Pressure on the Weld Quality for Magnetic Pulse Welded Sheet Joints

This paper examines the effect of reduced ambient pressure during the welding process on the quality of magnetic pulse weld seams. For this purpose, a specifically developed vacuum chamber was applied, which enables a reproducible implementation. This, in turn, prepared the ground for a systematic examination of this promising process parameter. The tests focused on comparison of the weld seams realized with different currents and acceleration distances under atmospheric pressure and in the vacuum chamber. Here, both similar (EN AW-1050-H14) and dissimilar material combinations were considered (EN AW-1050A-H14 + S235JR; EN-AW 6016-T6 + DC04). The evaluation criteria for the quality of the welds were the tensile strength of the joint and the size of the weld seam

Deriving Bounds on the Size of Spatial Areas

Many application domains such as surveillance, environmental monitoring or sensor-data processing need upper and lower bounds on areas that are covered by a certain feature. For example, a smart-city infrastructure might need bounds on the size of an area polluted with fine-dust, to re-route combustion-engine traffic. Obtaining such bounds is challenging, because in almost any real-world application, information about the region of interest is incomplete, e.g., the database of sensor data contains only a limited number of samples. Existing approaches cannot provide upper and lower bounds or depend on restrictive assumptions, e.g., the area must be convex. Our approach in turn is based on the natural assumption that it is possible to specify a minimal diameter for the feature in question. Given this assumption, we formally derive bounds on the area size, and we provide algorithms that compute these bounds from a database of sensor data, based on geometrical considerations. We evaluate our algorithms both with a real-world case study and with synthetic data

Scanning Probe Microscope Gigahertz Measurements on 200 Nanometer Wave Guides

Scanning probe microscopy is opening new applications in microelectronic engineering due to easy and reliable instrumentation in combination with superior resolution limits without any sample preparation under ambient conditions. Beside the standard topography imaging possible application are static and dynamic surface potential measurements, doping profiling, and scanning thermal applications. In this paper, we report dynamic voltage contrast measurements of analog and digital gigahertz signals on 200 nm wave guides within integrated microelectronic devices and components. The results are obtained by using a time resolved device internal test technique based on a scanning force microscope using the electrostatic force interaction. This technique enables voltage contrast even within passivated integrated circuits with nanometer spatial resolution and gigahertz measurement bandwidth and additionally millivolt sensitivity

Pair Excitations and Vertex Corrections in Fermi Fluids

Based on an equations--of--motion approach for time--dependent pair correlations in strongly interacting Fermi liquids, we have developed a theory for describing the excitation spectrum of these systems. Compared to the known ``correlated'' random--phase approximation (CRPA), our approach has the following properties: i) The CRPA is reproduced when pair fluctuations are neglected. ii) The first two energy--weighted sumrules are fulfilled implying a correct static structure. iii) No ad--hoc assumptions for the effective mass are needed to reproduce the experimental dispersion of the roton in 3He. iv) The density response function displays a novel form, arising from vertex corrections in the proper polarisation. Our theory is presented here with special emphasis on this latter point. We have also extended the approach to the single particle self-energy and included pair fluctuations in the same way. The theory provides a diagrammatic superset of the familiar GW approximation. It aims at a consistent calculation of single particle excitations with an accuracy that has previously only been achieved for impurities in Bose liquids.Comment: to be published in: JLTP (2007) Proc. Int. Symp. QFS2006, 1-6 Aug. 2006, Kyoto, Japa