R+EVUE THE B-SIDE

Visible from only one perspective at a time, architecture suffers the fate of never revealing itself as a whole. An inherent duplicity arises between what can be seen and what remains hidden. The back side—which never shows a representative face nor welcomes us into the building and rarely gets printed in glossy architecture magazines—is the overlooked side of architecture. As a result, we studied the backs of a few famous buildings. What we found is the B-side of architecture. Liberated from the front’s representative obligations, the B-side is an ambiguous space of programmatic, representative, contextual or even ideological experimentation. We represent our discoveries through a series of analytical and experimental drawings

Friction stir welded and deep drawn multi-material tailor welded blanks

The ever increasing demand for more resource-efficient and safer vehicles in today’s automotive industry makes lightweight construction techniques necessary. However, overcoming contradicting requirements arising from lightweight design and safety remains a challenging task. The extent to which lightweight measures can be applied in order to save fuel, heavily depends on the fact that rising safety requirements have to be met by increasing strength of parts. This contradicting demand for parts with high strength and low weight leads to the development of new production technologies. One example, regarding car body components, is the tailor welded blank (TWB) technology. In tailor welded blanks, materials and thicknesses are locally adapted to meet the needed strength and strain properties while keeping the weight as low as possible. While tailor welded blanks consisting of similar materials with different thicknesses are already used in vehicles, the use of TWBs with dissimilar materials, e.g. steel and aluminum, is still in development due to the problems in joining dissimilar materials. Especially when manufacturing parts made of TWBs through joining and subsequent deep drawing, the joint needs to have very good strength properties in order not to fail during forming. One way to overcome these joining difficulties is friction stir welding. In this paper, a methodology is presented to produce multi-material tailor welded blanks with varying thicknesses through friction stir welding (FSW) and deep drawing in a subsequent step. A newly developed FSW joint configuration is used to weld steel sheets in 1 mm thickness to 2 mm thick aluminum sheets. A welding parameter study is conducted to investigate the influence of the process parameters on the joint quality. Tensile and Nakajima tests show that the joint strength, obtained with optimal process parameters, exceeds the strength of the steel base material. Thus, failure occurs in the steel, whereas the joint remains intact. The friction stir welded blanks were furthermore deep drawn. Two different tool approaches were tested to compensate the different sheet thicknesses during the forming process. Using the more suitable approach, blanks were deep drawn with three different punch geometries to show the potential of friction stir welding for the manufacturing of multi-material tailor welded blanks

R+EVUE 20%

Organizational and administrative activities have shed their typological corset. Having cut spatial ties to the office, they are now at home almost anywhere. According to current studies, around 20% of office space in Germany will be obsolete in the medium term . This corresponds to a floor area of more than 75 million square meters. Calculated against the average per capita living space of 47,7 sqm , this represents enough space to house almost 2 million people. This equation is grossly simplified. It is problematic for, amongst other reasons, its exclusion of variables such as a building’s structural character, its urban location, and its proximity to technical and social infrastructures. The current demand for living space - especially in metropolitan areas - and the simultaneous necessity to establish more sustainable architectural practices, makes the conversion of existing buildings inevitable. This brings the above-mentioned issues to the fore, and will require the analysis of these buildings’ potentials and the architectural tools for exploiting them. R+EVUE 2 presents ten case studies, each making use of the same already-vacant office structure: an administrative building from the 1970s in Hamburg Wansbek. The object under investigation serves as a stand-in for the office buildings which pervade the peripheries of large German cities. Through consideration of this building’s specific structural and urban characteristics, various strategies for reappropriation are examined. The studies were produced systematically: the same office structure superimposed with ten residential projects, selected to form a broad typological spectrum. The frictions and conflicts which arise during this overlay process become catalysts for specific design solutions and raise more general questions about the reappropriation of existing structures. By adapting the characteristic typological features of the residential buildings to the structure of the office building, new and unexpected approaches are generated. The depth and extent of each study’s intervention is measurable against the existing structure. In the form of red-yellow plans and visualizations, both demolition measures and structural additions are clearly illustrated. The excerpt from the portfolio of office buildings is contrasted with a selection of residential building references. The ten residential building references cover a wide range of different circulation typologies, apartment types, construction principles and scales. The different housing references are all projected onto the structure of one vacant office building. Because its concrete skeleton is typical for an entire generation of commercial structures, the findings of the housing projections resonate beyond this specific case study

Autonomic Management of Large Clusters and Their Integration into the Grid

We present a framework for the co-ordinated, autonomic management of multiple clusters in a compute center and their integration into a Grid environment. Site autonomy and the automation of administrative tasks are prime aspects in this framework. The system behavior is continuously monitored in a steering cycle and appropriate actions are taken to resolve any problems. All presented components have been implemented in the course of the EU project DataGrid: The Lemon monitoring components, the FT fault-tolerance mechanism, the quattor system for software installation and configuration, the RMS job and resource management system, and the Gridification scheme that integrates clusters into the Grid

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Abschlussbericht zum Projekt "Ressourcenschonende Mischschweißverbindungen für Hochleistungs-Leichtbauverbunde"

Im Rahmen des Projektes wurde das Rührreibschweißen als ressourceneffizientes und umweltfreundliches Fertigungsverfahren zur Herstellung von beanspruchungs- und gewichtsoptimierten Automobilbauteilen erforscht. Dabei galt es, Aluminium und Stahl in verschiedenen Dicken durch Rührreibschweißen zu fügen und durch anschließendes Umformen zum End- bzw. Zwischenprodukt umzuformen. Die auf die Festigkeiten der Werkstoffe angepassten Blechdicken führen zu einer optimalen Ausnutzung der Werkstoffe, da an jeder Stelle der Werkstoff verwendet werden kann, der die lokalen Anforderungen am besten erfüllt. Durch den Einsatz dieser sogenannten Tailor Welded Blanks sinkt der Werkstoffverbrauch insgesamt und es können auf Leichtbau optimierte Bauteile hergestellt werden. Im Rahmen des Projektes wurden verschiedene Aluminium- und Stahlgüten in unterschiedlichen Dicken durch Rührreibschweißen gefügt und die Festigkeits- sowie Umformeigenschaften ermittelt. Da die Einhaltung von engen Toleranzen mit hohen Kosten in der Fertigung einhergeht, wurden die für den Prozess notwendigen Toleranzen untersucht, Lösungen zum Umgang mit diesen Toleranzen erarbeitet und Anforderungen an Anlagen zur Produktion von Tailor Welded Blanks identifiziert. Zudem wurde das Umformen von Blechen mit unterschiedlichen Materialen und Blechdicken untersucht. Darüber hinaus wurde eine Reihe weiterer Themen wie das Verschweißen von Gusswerkstoffen und Wärmebehandlungsstrategien beleuchtet. Abschließend wurden Demonstratorbauteile in Form von Tailor Welded Blanks in Aluminium-Stahl- Mischbauweise durch Rührreibschweißen und anschließendes Umformen gefertigt

Spin-Crossover Iron(II) Coordination Polymer with Fluorescent Properties: Correlation between Emission Properties and Spin State

A spin-crossover coordination polymer [Fe­(L1)­(bipy)]_<i>n</i> (where L = a N₂O₂^2– coordinating Schiff base-like ligand bearing a phenazine fluorophore and bipy = 4,4′-bipyridine) was synthesized and exhibits a 48 K wide thermal hysteresis above room temperature (<i>T</i>_1/2↑ = 371 K and <i>T</i>_1/2↓ = 323 K) that is stable for several cycles. The spin transition was characterized using magnetic measurements, Mössbauer spectroscopy, and DSC measurements. <i>T</i>-dependent X-ray powder diffraction reveals a structural phase transition coupled with the spin transition phenomenon. The dimeric excerpt {(μ-bipy)­[FeL1­(MeOH)]₂}·​2MeOH of the coordination polymer chain crystallizes in the triclinic space group <i>P</i>1̅ and reveals that the packing of the molecules in the crystal is dominated by hydrogen bonds. Investigation of the emission properties of the complexes with regard to temperature shows that the spin crossover can be tracked by monitoring the emission spectra, since the emission color changes from greenish to a yellow color upon the low spin-to-high spin transition

Dysfunction of persisting β cells is a key feature of early type 2 diabetes pathogenesis.

Type 2 diabetes is characterized by peripheral insulin resistance and insufficient insulin release from pancreatic islet beta cells. However, the role and sequence of b cell dysfunction and mass loss for reduced insulin levels in type 2 diabetes pathogenesis are unclear. Here, we exploit freshly explanted pancreas specimens from metabolically phenotyped surgical patients using an in situ tissue slice technology. This approach allows assessment of beta cell volume and function within pancreas samples of metabolically stratified individuals. We show that, in tissue of pre-diabetic, impaired glucose-tolerant subjects, beta cell volume is unchanged, but function significantly deteriorates, exhibiting increased basal release and loss of first-phase insulin secretion. In individuals with type 2 diabetes, function within the sustained beta cell volume further declines. These results indicate that dysfunction of persisting beta cells is a key factor in the early development and progression of type 2 diabetes, representing a major target for diabetes prevention and therapy

Ultrasound for the evaluation of femoroacetabular impingement of the cam type. Diagnostic performance of qualitative criteria and alpha angle measurements

OBJECTIVE: To develop and assess a technique to evaluate cam type femoroacetabular impingement (FAI) using ultrasound (US). METHODS: Fifty patients (24 women, 26 men) were included (mean age: 39.1 years; age range: 16-59). US images of the anterior and anterosuperior contour of the femoral neck were obtained and analysed in 50 patients. Non-spherical shape of the head-neck junction (cam deformity), bony protuberances at the femoral neck, shape of the femoral neck (waist deficiency) and alpha angle were assessed. Magnetic resonance (MR) arthrography served as the standard of reference. Diagnostic performance and receiver operating characteristics (ROC) curves were calculated. RESULTS: Based on MR arthrography 28 patients had cam-type FAI. On US, an anterosuperior cam deformity was seen in 40/44 patients (Reader 1/Reader 2; sensitivity 93%/89%, specificity 36%/14%). A bony protuberance anterosuperiorly in 23/13 patients (sensitivity 71%/32%, specificity 86%/82%) and an anterosuperior waist deficiency in 19/35 patients (sensitivity 25%/54%, specificity 100%/54%). Sensitivity and specificity of the other criteria were lower than 70% (average of Reader 1 & 2). CONCLUSION: A technique to evaluate cam type FAI using US is presented. The detection of an anterosuperior cam deformity is sensitive, and presence of an anterosuperior bony protuberance is specific for cam FAI. Alpha angle measurements are not helpful in establishing the diagnosis