4,428 Works

BioElectroPlast - Mit Bakterien Bioplastik herstellen - KIT.audio | Der Forschungspodcast des Karlsruher Instituts für Technologie, Folge 24 am 01.10.2020

Almut Ochsmann &
Eine neue Biotechnologie, die vielversprechend klingt: Bakterien verbrauchen CO2 aus industriellen Rauchgasen und stellen daraus die Grundsubstanz für biologisch abbaubaren Kunststoff her. Forscherinnen und Forscher um Professor Johannes Gescher vom Institut für Angewandte Biowissenschaften haben aus Matschproben von den Azoren einen Organismus isoliert, der das kann. Das relativ neue Verfahren heißt mikrobielle Elektrosynthese. Im Projekt BioElectroPlast schaffen die Wissenschaftlerinnen und Wissenschaftler nicht nur eine Alternative zu erdölbasiertem Kunststoff, sondern reduzieren gleichzeitig Treibhausgase.

Preface: Advances in post-processing and blending of deterministic and ensemble forecasts

S. Hemri, Sebastian Lerch, M. Taillardat, S. Vannitsem & D. S. Wilks
The special issue on advances in post-processing and blending of deterministic and ensemble forecasts is the outcome of several successful successive sessions organized at the General Assembly of the European Geosciences Union. Statistical post-processing and blending of forecasts are currently topics of important attention and development in many countries to produce optimal forecasts. Ten contributions have been received, covering key aspects of current concerns on statistical post-processing, namely the restoration of inter-variable dependences, the impact...

Die räumliche Dimension residenzieller Multilokalität, ein prädestiniertes thematisches Bindeglied zwischen Forschung und Lehre

Markus Kaltenbach

Progress in thermal management and safety of cells and packs by testing in battery calorimeters

Carlos Ziebert, Nils Uhlmann, Magnus Rohde & Hans Jürgen Seifert
With increasing energy density the safety and the thermal management of Li-ion batteries is becoming more and more important, because the thermal runaway can cause an ignition or even explosion of the battery with simultaneous release of toxic gases. In the last nine years we have established battery calorimetry as a powerful and versatile electrochemical-thermal characterization technique, which allows both advancements for the thermal management and the safety of batteries. With six adiabatic Accelerating Rate...

Severe thunderstorms with large hail across Germany in June 2019

Jannik Wilhelm, Susanna Mohr, Heinz Jürgen Punge, Bernhard Mühr, Manuel Schmidberger, James E. Daniell, Kristopher M. Bedka & Michael Kunz

HeAT – a Distributed and GPU-accelerated TensorFramework for Data Analytics

Markus Götz, Charlotte Debus, Daniel Coquelin, Kai Krajsek, Claudia Comito, Philipp Knechtges, Björn Hagemeier, Michael Tarnawa, Simon Hanselmann, Martin Siggel, Achim Basermann & Achim Streit
To cope with the rapid growth in available data, the efficiency of data analysis and machine learning libraries has recently received increased attention. Although great advancements have been made in traditional array-based computations, most are limited by the resources available on a single computation node. Consequently, novel approaches must be made to exploit distributed resources, e.g. distributed memory architectures. To this end, we introduce HeAT, an array-based numerical programming framework for large-scale parallel processing with...

Preserving Secrecy in Online Social Networks: Data Outsourcing, Access Control, and Secrecy Schemes

Gabriela Suntaxi
In den vergangenen Jahren haben sich Online Social Networks (OSNs) wie Facebook und Foursquare zu einer beliebten Möglichkeit der Kommunikation und des Teilens von Informationen unter Nutzern entwickelt. OSNs sind virtuelle Communitys, die Informationen über die Nutzer und die zwischen ihnen bestehenden Beziehungen, wie z.~B. Freundschaften, enthalten. Zusätzlich dazu, dass eine Interaktion der Nutzer untereinander ermöglicht wird, bieten OSNs ihren Nutzern normalerweise verschiedene Arten von Dienstleistungen an, wie z.~B. die Abfrage nach Freunden innerhalb einer...

Elektromobile Flotten im lokalen Energiesystem mit Photovoltaikeinspeisung unter Berücksichtigung von Unsicherheiten

Katrin Seddig
In diesem Buch wird ein Modell entwickelt, welches zur Identifizierung der Lastverschiebepotenziale von elektromobilen Flotten unter Berücksichtigung der Integration von Photovoltaik-Erzeugung und Unsicherheiten nutzbar ist. Es werden unterschiedliche Ansätze unter der Anwendung von Simulation, deterministischer und stochastischer Optimierung entwickelt, um den Ladevorgang von drei verschiedenen Elektrofahrzeugflotten an einer gemeinsam genutzten Ladeinfrastruktur unter Unsicherheit zu planen.

Search for a doubly charged DDK bound state in Υ(1S, 2S) inclusive decays and via direct production in e⁺e⁻ collisions at √s = 10.520, 10.580, and 10.867 GeV

Y. Li, S. Jia, C. P. Shen, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, M. Campajola, D. Červenkov … & V. Zhulanov

Adaptive inertia emulation control for high-speed flywheel energy storage systems

Shahab Karrari, Hamid Reza Baghaee, Giovanni De Carne, Mathias Noe & Joern Geisbuesch
Low-inertia power systems suffer from a high rate of change of frequency (ROCOF) during a sudden imbalance in supply and demand. Inertia emulation techniques using storage systems, such as flywheel energy storage systems (FESSs), can elp to reduce the ROCOF by rapidly providing the needed power to balance the grid. In this work, a new adaptive ontroller for inertia emulation using high-speed FESS is proposed. The controller inertia and damping coefficients vary using a combination...

Temperature Homogenization of Co-Integrated Shape Memory—Silicon Bimorph Actuators

Gowtham Arivanandhan, Zixiong Li, Sabrina Curtis, Prasanth Velvaluri, Eckhard Quandt & Manfred Kohl

Chemical Reactivity of Supported ZnO Clusters: Undercoordinated Zinc and Oxygen Atoms as Active Sites

Xiaojuan Yu, Jannik P. Roth, Junjun Wang, Eric Sauter, Alexei Nefedov, Stefan Heißler, Gianfranco Pacchioni, Yuemin Wang & Christof Wöll
The growth of ZnO clusters supported by ZnO‐bilayers on Ag(111) and the interaction of these oxide nanostructures with water have been studied by a multi‐technique approach combining temperature‐dependent infrared reflection absorption spectroscopy (IRRAS), grazing‐emission X‐ray photoelectron spectroscopy, and density functional theory calculations. Our results reveal that the ZnO bilayers exhibiting graphite‐like structure are chemically inactive for water dissociation, whereas small ZnO clusters formed on top of these well‐defined, yet chemically passive supports show extremely high...

Zur Dynamik eines unwuchtigen Rotors mit Selbstauswuchtsystem

Olga Drozdetskaya
Selbstauswuchtsysteme sind im Bereich der Technik weit verbreitet, um das Schwingungsniveau von rotierenden Maschinen mit variabler Unwucht, wie z.B. Waschmaschinen, Zentrifugen, optische Laufwerke u.v.a.m., zu reduzieren. Ein Unwuchtausgleich mit besagten Selbstauswuchtsystemen ist dabei nur im überkritischen Drehzahlbereich der Maschinen möglich. Im Zuge einer Beschleunigung der Maschine auf einen im überkritischen Drehzahlbereich liegenden Betriebspunkt passiert diese zwangsläufig ein oder mehrere Resonanzfrequenzen, an denen es zu unerwünschten dynamischen Effekten kommen kann, die in der Regeln von einer...

Structure and properties of MgB2bulks: Ab-initio simulations compared to experiment

V V Romaka, T A Prikhna, M Eisterer, A P Shapovalov, W Goldacker, V E Moshchil, A Kozyrev, M Rindfleisch, M Tompsic, E E Hellstrom, G E Grechnev, V Sh Zhang, F Yang & Ch Li
Analysis of XRD patterns by Rietveld refinement has been shown that the main phase of superconducting MgB$_{2}$-based bulk materials (with high level of superconducting characteristics) has AlB$_{2}$ type structure and near MgB$_{1.8-1.68}$O$_{0.2-0.32}$ stoichiometry. The materials demonstrated the critical current densities up to 0.9 – 0.4 MA/cm$^{2}$ jc (at 0 - 1 T, 20 K); up to 15 T B$_{c2}$ (at 22.5 K) and B$_{irr}$ (at 18 K). The ab-initio simulation confirmed (1) benefits in binding...

Transient Thermal Model for Ball Bearings in Electrical Machines

Felix Hoffmann, Donatas Silys & Martin Doppelbauer

Supplement: MIPAS VMR data and climatological circulation fields for publication 10.5194/acp-2019-704

Udo Grabowski
This dataset provides the supplementary MIPAS VMR data and resulting climatology of atmospheric circulation fields 2002-2012 for publication 10.5194/acp-2019-704, using the software provided in 10.5445/IR/1000127728.

The level of knowledge, use and acceptance of LCA among designers in Germany: A contribution to IEA EBC Annex 72

Thomas Lützkendorf & Maria Balouktsi
Architects and engineers have become more concerned about the environmental consequences of their design solutions. Knowledge about Life Cycle Assessment (LCA) is crucial for the necessary building sector decarbonisation, as well as for mitigating other negative environmental impacts. In Germany, designers' attitudes towards LCA have not been analysed since 2005. However, since then, certain developments – such as the establishment of the sustainability assessment systems BNB and DGNB – have taken place. In 2019, as...

Impact and risk analysis in the integrated development of product and production system

Tobias Stürmlinger, Dinah Jost, Constantin Mandel, Matthias Behrendt & Albert Albers
The assessment of risks and influences of engineering changes of a product or production system on affected technical (sub-) systems of the same or a different domain are of great importance in order to evaluate possible alternatives and to select solutions. The increasing complexity of mechatronic products and production systems with Industry 4.0 technology reinforces the demand for a method that supports engineers in decision making in both technical and strategic issues. By using the...

Image-based roughness estimation of laser cut edges with a convolutional neural network

Leonie Tatzel & Fernando Puente León
Laser cutting of metals is a complex process with many influencing factors. As some of them are subject to change, the cut quality needs to be checked regularly. This paper aims to estimate the roughness of cut edges based on RGB images instead of surface topography measurements. We trained a convolutional neural network (CNN) on a broad database of images and corresponding roughness values. The CNN estimates the roughness well with a mean error of...

Thermal Limits of Promising Candidate Materials for Accident Tolerant Fuel Claddings

Mirco Große
Since the Fukushima disaster, efforts are made worldwide to improve the accident performance of nuclear fuel. The development of the so called accident tolerant fuel (ATF) comprises both, new fuels and new cladding materials. Main goal of the fuel development are the increase of thermal conductivity to reduce the thermal capacity of the fuel after termination of the nuclear chain reaction. Examples are developments of UN and U3Si2 fuel. The goal of the cladding developments...

Data Science and Big Data in Upper Secondary Schools: A Module to Build up First Components of Statistical Thinking in a Data Science Curriculum

Rolf Biehler, Daniel Frischemeier, Susanne Podworny, Thomas Wassong, Lea Budde, Birte Heinemann & Carsten Schulte
Within the framework of a design-based research project, computer science educators and statistics educators at Paderborn University designed a pilot course on the subject of data science and big data. It addresses upper secondary students and was realized by weekly sessions (three hours) over seven months. The whole course that is intended to introduce upper secondary school students to the field of data science consists of four modules. In module 1, the learners are introduced...

Heat load budgeting of a superconducting induction heater’s commercial cryocooler-based cryostat

Lennard Busch

Insight into the X‐ray absorption spectra of Cu‐porphyrazines from electronic structure theory

Esma Birsen Boydas, Bernd Winter, David Batchelor & Michael Roemelt
Transition metal porphyrazines are a widely used class of compounds with applications in catalysis, organic solar cells, photodynamic therapy, and nonlinear optics. The most prominent members of that family of compounds are metallophtalocyanines, which have been the subject of numerous spectroscopic and theoretical studies. In this work, the electronic structure and X‐ray absorption characteristics of three Cu‐porphyrazine derivatives are investigated by means of modern electronic structure theory. More precisely, the experimentally observed N K‐edge and...

Leveraging multilingual descriptions for link prediction: Initial experiments

G. A. Gesese, M. Alam, F. Hoppe & H. Sack
In most Knowledge Graphs (KGs), textual descriptions ofentities are provided in multiple natural languages. Additional informa-tion that is not explicitly represented in the structured part of the KGmight be available in these textual descriptions. Link prediction modelswhich make use of entity descriptions usually consider only one language.However, descriptions given in multiple languages may provide comple-mentary information which should be taken into consideration for thetasks such as link prediction. In this poster paper, the benefits of...

Desalination of Seawater Using Cationic Poly(acrylamide) Hydrogels and Mechanical Forces for Separation

Christian Fengler, Lukas Arens, Harald Horn & Manfred Wilhelm
In this study, the ability of cationic poly(acrylamide-co-(3-acrylamidopropyl)trimethylammonium chloride) hydrogels to desalinate seawater is explored, where the salt separation is based on the partial rejection of mobile salt ions by the fixed charges along the polymer backbone. Water absorbency measurements reveal that artificial seawater-containing divalent ions (Mg$^{2+}$, Ca$^{2+}$, and SO$_{4}$$^{2-}$) drastically decrease the swelling capacity of previously employed anionic poly(acrylic acid-co-sodium acrylate) hydrogels, whereas no influence on the swelling behavior of the synthesized cationic hydrogels...

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