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Seismic verification of existing masonry buildings and strengthening with reinforced concrete jackets
No full textA methodology for assessment, seismic verification and strengthening of existing masonry buildings is presented in this paper. The verification is performed using a calculation model calibrated with the results from ambient vibration measurements. The calibrated model serves as an input for a deformation-based verification procedure based on the Capacity Spectrum Method (CSM). The bearing capacity of the building is calculated from experimental capacity curves of the individual walls idealized with bilinear elastic-perfectly plastic curves. The experimental capacity curves were obtained from in-plane cyclic loading tests on unreinforced and strengthened masonry walls with reinforced concrete jackets. The seismic action is compared with the load-bearing capacity of the building considering non-linear material behavior with its post-peak capacity. The application of the CSM to masonry buildings and the influence of a traditional strengthening method are demonstrated on the example of a public school building in Skopje, Macedonia
Cramér-von-Mises tests for the distribution of the excess over a confidence level
No full textThe Cramér-von-Mises distance is applied to the distribution of the excess over a confidence level. Asymptotics of related statistics are investigated, and it is seen that the obtained limit distributions differ from the classical ones. For that reason, quantiles of the new limit distributions are given and new bootstrap techniques for approximation purposes are introduced and justified. The results motivate new one-sample goodness-of-fit tests for the distribution of the excess over a confidence level and a new confidence interval for the related fitting error. Simulation studies investigate size and power of the tests as well as coverage probabilities of the confidence interval in the finite sample case. A practice-oriented application of the Cramér-von-Mises tests is the determination of an appropriate confidence level for the fitting approach. The adoption of the idea to the well-known problem of threshold detection in the context of peaks over threshold modelling is sketched and illustrated by data examples
550 nm : Farbwechsel von Tieren - Kommunikation in der Natur
No full text„550 nm“ befasst sich mit dem physiologischen Farbwechsel von Tieren. Einige Fische, Amphibien und Reptilien – wie beispielsweise das Chamäleon oder der Tintenfisch – können ihre Körperfarbe schnell wechseln. Unsere Natur leidet unter Kriegen und dem Klimawandel und verliert dadurch ihre Schönheit. Diese zeichnet sich vor allem durch die beachtliche Diversität der Körperfärbung von Tieren aus. Die Funktionen erstrecken sich über Tarnung, Auflauern oder Warnung bis hin zu einer Werbefärbung. Nicht nur Tiere nutzen Farbe als Ausdrucks- und Kommunikationsmittel. Auch Designer*innen bedienen sich an Farben, um Stimmungen zu vermitteln oder um Aufmerksamkeit und Individualität zu generieren. In „550 nm“ wird das Phänomen des Farbwechsels durch Illustrationen visualisiert und soll als Inspiration für Designinnovationen dienen
Wiegand-Effect-Powered Wireless IT Sensor Node
No full textWith the growing interest in small distributed sensors for the “Internet of Things”, more attention is being paid to energy harvesting techologies. Reducing or eliminating the need for external power sources or batteries make devices more self-sufficient, more reliable, and reduces maintenance requirements. The Wiegand effect is a proven technology for harvesting small amounts of electrical power from mechanical motion
CO2 Meter: a do-it-yourself carbon dioxide measuring device for the classroom
No full textIn this paper we report on CO2 Meter, a do-it-yourself carbon dioxide measuring device for the classroom. Part of the current measures for dealing with the SARS-CoV-2 pandemic is proper ventilation in indoor settings. This is especially important in schools with students coming back to the classroom even with high incidents rates. Static ventilation patterns do not consider the individual situation for a particular class. Influencing factors like the type of activity, the physical structure or the room occupancy are not incorporated. Also, existing devices are rather expensive and often provide only limited information and only locally without any networking. This leaves the potential of analysing the situation across different settings untapped. Carbon dioxide level can be used as an indicator of air quality, in general, and of aerosol load in particular. Since, according to the latest findings, SARS-CoV-2 can be transmitted primarily in the form of aerosols, carbon dioxide may be used as a proxy for the risk of a virus infection. Hence, schools could improve the indoor air quality and potentially reduce the infection risk if they actually had measuring devices available in the classroom. Our device supports schools in ventilation and it allows for collecting data over the Internet to enable a detailed data analysis and model generation. First deployments in schools at different levels were received very positively. A pilot installation with a larger data collection and analysis is underway
Breathe
No full textEin nachhaltiges, autonomes Fahrzeug, das in einer extrem schnellen und hektischen Welt, geprägt durch Digitalisierung und Urbanisierung, einen Moment der Ruhe bieten soll; eine Pause von der ständigen Flut von Eindrücken und Informationen. Ein immersives Design, das meditative und kreative Prozesse unterstützt und Mensch-Mensch sowie Mensch-Natur Begegnungen fördert
Schlüter Projekt X
No full textSchlüter Projekt X ist die fiktive Reanimation des Traktorenherstellers Schlüter. Dabei geht es darum, auf Basis der originalen Traktoren eine moderne Maschine zu entwerfen, welche die bewährte und beliebte Formsprache mit moderner Technologie und aktuellen Funktionen verbindet, um den Anforderungen der modernen Landwirtschaft gerecht zu werden. Dazu wurde Projekt X stark modular aufgebaut. Die Fahrzeugkabine lässt sich um 180° drehen und gegebenenfalls durch ein vollkommen autonomes Modul austauschen. Die Reifen lassen sich bei Bedarf durch Ketten ersetzen. Projekt X wird elektronisch angetrieben, zur Vermeidung langer Ladezeiten lässt sich der gesamte Akkublock in der Motorhaube austauschen
On the influence of elasticity on propeller performance: a parametric study
No full textThe aerodynamic performance of propellers strongly depends on their geometry and, consequently, on aeroelastic deformations. Knowledge of the extent of the impact is crucial for overall aircraft performance. An integrated simulation environment for steady aeroelastic propeller simulations is presented. The simulation environment is applied to determine the impact of elastic deformations on the aerodynamic propeller performance. The aerodynamic module includes a blade element momentum approach to calculate aerodynamic loads. The structural module is based on finite beam elements, according to Timoshenko theory, including moderate deflections. Several fixed-pitch propellers with thin-walled cross sections made of both isotropic and non-isotropic materials are investigated. The essential parameters are varied: diameter, disc loading, sweep, material, rotational, and flight velocity. The relative change of thrust between rigid and elastic blades quantifies the impact of propeller elasticity. Swept propellers of large diameters or low disc loadings can decrease the thrust significantly. High flight velocities and low material stiffness amplify this tendency. Performance calculations without consideration of propeller elasticity can lead to decreased efficiency. To avoid cost- and time-intense redesigns, propeller elasticity should be considered for swept planforms and low disc loadings