TY - JOUR
AU - Greil, Stefan
AU - Overesch, Michael
AU - Rohlfing-Bastian, Anna
AU - Schreiber, Ulrich
AU - Sureth-Sloane, Caren
ID - 42635
IS - 4
JF - Intertax
TI - Towards an Amended Arm´s Length Principle - Tackling Complexity and Implementing Destination Rules in Transfer Pricing
VL - 51
ER -
TY - CONF
AB - We demonstrate the numerical and experimental realization of optimized optical traveling-wave antennas made of low-loss dielectric materials. These antennas exhibit highly directive radiation patterns and our studies reveal that this nature comes from two dominant guided TE modes excited in the waveguide-like director of the antenna, in addition to the leaky modes. The optimized antennas possess a broadband nature and have a nearunity radiation efficiency at an operational wavelength of 780 nm. Compared to the previously studied plasmonic antennas for photon emission, our all-dielectric approach demonstrates a new class of highly directional, low-loss, and broadband optical antennas.
AU - Farheen, Henna
AU - Yan, Lok-Yee
AU - Leuteritz, Till
AU - Qiao, Siqi
AU - Spreyer, Florian
AU - Schlickriede, Christian
AU - Quiring, Viktor
AU - Eigner, Christof
AU - Silberhorn, Christine
AU - Zentgraf, Thomas
AU - Linden, Stefan
AU - Myroshnychenko, Viktor
AU - Förstner, Jens
ED - García-Blanco, Sonia M.
ED - Cheben, Pavel
ID - 43051
KW - tet_topic_opticalantenna
T2 - Integrated Optics: Devices, Materials, and Technologies XXVII
TI - Tailoring the directive nature of optical waveguide antennas
ER -
TY - CONF
AB - We demonstrate a large-scale two dimensional silicon-based optical phased array (OPA) composed of nanoantennas with circular gratings that are balanced in power and aligned in phase, required for producing desired radiation patterns in the far-field. The OPAs are numerically optimized to have an upward efficiency of up to 90%, targeting radiation concentration mainly in the field of view. We envision that our OPAs have the ability of generating complex holographic images, rendering them an attractive candidate for a wide range of applications like LiDAR sensors, optical trapping, optogenetic stimulation and augmented-reality displays.
AU - Farheen, Henna
AU - Strauch, Andreas
AU - Scheytt, J. Christoph
AU - Myroshnychenko, Viktor
AU - Förstner, Jens
ED - García-Blanco, Sonia M.
ED - Cheben, Pavel
ID - 43052
KW - tet_topic_opticalantenna
T2 - Integrated Optics: Devices, Materials, and Technologies XXVII
TI - Optimized silicon antennas for optical phased arrays
ER -
TY - JOUR
AB -
AU - Heck, Tamara
AU - Steinhardt, Isabel
AU - Rahal, Rima-Maria
AU - Schubotz, Moritz
AU - Scholl, Dominik
AU - Behrens, Sarah
ID - 43094
JF - Research Ideas and Outcomes
KW - Open Science
SN - 2367-7163
TI - Bootstrapping the Open Science culture: The fellowship approach
VL - 9
ER -
TY - JOUR
AU - Black, Tobias
AU - Fuest, Mario
AU - Lankeit, Johannes
AU - Mizukami, Masaaki
ID - 43105
JF - Nonlinear Analysis: Real World Applications
KW - Applied Mathematics
KW - Computational Mathematics
KW - General Economics
KW - Econometrics and Finance
KW - General Engineering
KW - General Medicine
KW - Analysis
SN - 1468-1218
TI - Possible points of blow-up in chemotaxis systems with spatially heterogeneous logistic source
VL - 73
ER -
TY - JOUR
AU - Wippermann, Jan
AU - Meschut, Gerson
AU - Koshukow, Wikentij
AU - Liebsch, Alexander
AU - Gude, Maik
AU - Minch, Steven
AU - Kolbe, Björn
ID - 43154
JF - Welding in the World
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
SN - 0043-2288
TI - Correction: Thermal influence of resistance spot welding on a nearby overmolded thermoplastic–metal joint
ER -
TY - CONF
AU - Görel, Gamze
AU - Hellmich, Frank
AU - Löper, Marwin Felix
ID - 43177
TI - Förderung der sozialen Partizipation von Kindern im inklusiven Unterricht. Workshop auf dem 9. Paderborner Grundschultag. Thema: „Demokratie von Anfang an! Demokratie in der Grundschule erfahren, mitgestalten und reflektieren“
ER -
TY - CHAP
AU - Vitt, Vivian
AU - Häsel-Weide, Uta
ID - 43227
T2 - Mathematica Didactica, 46
TI - Reziprokes Peer-Tutoring zur Förderung von Schüler*innen mit Schwierigkeiten beim Mathematiklernen.
ER -
TY - CHAP
AU - Häsel-Weide, Uta
AU - Nührenbörger, M.
ID - 43226
T2 - Mathematica Didactica, 46
TI - Inklusive Praktiken unterrichtsintegrierter Förderung im Mathematikunterricht.
ER -
TY - GEN
AU - Rüther, Torben
AU - Schmid, Hans-Joachim
ID - 43236
KW - CDMA
TI - CDMA: Centrifugal Differential Mobility Analyzer - Ein Messprinzip zur Bestimmung von Multidimensionalen Partikeleigenschaften (Vortrag)
ER -
TY - JOUR
AU - Schroeter-Wittke, Harald
ID - 43248
IS - 1
JF - Zeitschrift für Pädagogik und Theologie
SN - 1437-7160
TI - Thorsten Knauth/Rainer Möller/Annebelle Pithan (Hg.), Inklusive Religionspädagogik der Vielfalt. Konzeptionelle Grundlagen und didaktische Konkretionen. Münster/New York 2020
VL - 75
ER -
TY - GEN
AU - Lutters, Nicole
AU - Buckmann, Felix
AU - Kenig, Eugeny Y.
ID - 43280
TI - Zur experimentellen Untersuchung der Reinstoffkondensation in Kissenplatten-Wärmeübertragern
ER -
TY - JOUR
AB - Laser structuring to improve the adhesion properties of steel substrates in fiber-metal laminates offers many advantages that are highly suitable for modern industrial requirements. Maintenance and energy costs are relatively low, it is easy to automate, and there are no by-products such as chemicals or abrasives to dispose of or recycle. This makes laser structuring a particularly environmentally friendly process, which is nowadays more important than ever. On the other hand, the process time for laser structuring is much higher than for chemical pre-treatment, for example. In past studies, the time and cost efficiency of the laser structuring process has tended to play a minor role. However, there are approaches in which laser structured surfaces are adapted to the shear stress peaks occurring within the adhesive layer, thus requiring only partial structuring of the area to be bonded, potentially saving process time. In this experimental study, electrolytically galvanized steel substrates were partially laser structured to match the shear stress distribution and then bonded to a carbon fiber-reinforced plastic. The adhesion properties achieved were characterized using shear tensile tests and compared with the properties of the fully structured ones. With the partial laser structuring, a saving of 66 % of the conventional process time was achieved while maintaining 95 % of the same shear strength.
AU - Voswinkel, Dietrich
ID - 43371
JF - Journal of Manufacturing Processes
KW - Laser treatment Adhesive bonding Surface technology Hybrid materials
TI - Application of a new strategy for time-efficient laser treatment of galvanized steel substrates to improve the adhesion properties
VL - 94
ER -
TY - GEN
ED - Meine, Sabine
ED - Otto, Arnold
ED - Süßmann, Johannes
ID - 35062
SN - 978-3-8260-7218-5
TI - Musiklandschaften zwischen Rhein und Weser. Pluralisierung und Verflechtung entlang des Hellwegs in der Frühen Neuzeit. Unter Mitarbeit v. Markus Lauert
VL - 13
ER -
TY - CONF
AU - Bernemann, Sören Antonius
AU - Maćkowiak, Jan
AU - Maćkowiak, Jerzy
AU - Kenig, Eugeny
ID - 43393
TI - Computerunterstützte Strömungsuntersuchung von landwirtschaftlichen Abfällen
ER -
TY - CONF
AU - Trentinaglia, Roman
AU - Merschjohann, Sven
AU - Fockel, Markus
AU - Eikerling, Hendrik
ID - 43395
SN - 0302-9743
T2 - REFSQ 2023: Requirements Engineering: Foundation for Software Quality
TI - Eliciting Security Requirements – An Experience Report
ER -
TY - JOUR
AU - Hanusch, Maximilian
ID - 34832
IS - 21
JF - Annals of Global Analysis and Geometry
KW - Lax equation
KW - generalized Baker-Campbell-Dynkin-Hausdorff formula
KW - regularity of Lie groups
TI - The Lax Equation and Weak Regularity of Asymptotic Estimate Lie Groups
VL - 63
ER -
TY - CHAP
AU - Grydin, Olexandr
AU - Garthe, Kai-Uwe
AU - Yuan, Xueyang
AU - Broer, Jette
AU - Keßler, Olaf
AU - Králík, Rostislav
AU - Cieslar, Miroslav
AU - Schaper, Mirko
ED - Broek, Stephan
ID - 41959
SN - 2367-1181
T2 - Light Metals 2023
TI - Numerical and Experimental Investigation of Twin-Roll Casting of Aluminum–Lithium Strips
ER -
TY - GEN
AU - Ghazal, Abdulkarim
AU - Sadeghi-Kohan, Somayeh
AU - Reimer, Jan Dennis
AU - Hellebrand, Sybille
ID - 35204
KW - WORKSHOP
TI - On Cryptography Effects on Interconnect Reliability
ER -
TY - JOUR
AU - Brosch, Anian
AU - Wallscheid, Oliver
AU - Böcker, Joachim
ID - 43456
JF - IEEE Transactions on Power Electronics
KW - Electrical and Electronic Engineering
SN - 0885-8993
TI - Time-Optimal Model Predictive Control of Permanent Magnet Synchronous Motors Considering Current and Torque Constraints
ER -
TY - CHAP
AU - Strauß, Sara
ED - Mildorf, Jarmila
ED - Punzi, Eilsabeth
ED - Singer, Christoph
ID - 43459
SN - 9780197620540
T2 - Narrative and Mental Health
TI - Narrative Experiments with Medical Categorization and Normalization in B. S. Johnson's House Mother Normal
ER -
TY - GEN
AU - Dechert, Christopher
AU - Kengni Nkouemou, Augustin
AU - Kenig, Eugeny Y.
ID - 43111
TI - Vergleichende Untersuchung der Wirkung verschiedener Mikrostrukturen auf die Flüssigkeitsausbreitung
ER -
TY - JOUR
AB - High-contrast slab waveguide Bragg gratings with 1D periodicity are investigated. For specific oblique excitation by semi-guided waves at sufficiently high angles of incidence, the idealized structures do not exhibit any radiative losses, such that reflectance and transmittance for the single port mode add strictly up to one. We consider a series of symmetric, fully and partly etched finite gratings, for parameters found in integrated silicon photonics. These can act as spectral filters with a reasonably flattop response. Apodization can lead to more box shaped reflectance and transmittance spectra. Together with a narrowband Fabry–Perot filter, these configurations are characterized by reflection bands, or transmittance peaks, with widths that span three orders of magnitude.
AU - Hammer, Manfred
AU - Farheen, Henna
AU - Förstner, Jens
ID - 43245
IS - 4
JF - Journal of the Optical Society of America B
KW - tet_topic_waveguide
SN - 0740-3224
TI - How to suppress radiative losses in high-contrast integrated Bragg gratings
VL - 40
ER -
TY - JOUR
AU - Serino, Laura
AU - Gil López, Jano
AU - Stefszky, Michael
AU - Ricken, Raimund
AU - Eigner, Christof
AU - Brecht, Benjamin
AU - Silberhorn, Christine
ID - 44081
IS - 2
JF - PRX Quantum
KW - General Physics and Astronomy
KW - Mathematical Physics
KW - Applied Mathematics
KW - Electronic
KW - Optical and Magnetic Materials
KW - Electrical and Electronic Engineering
KW - General Computer Science
SN - 2691-3399
TI - Realization of a Multi-Output Quantum Pulse Gate for Decoding High-Dimensional Temporal Modes of Single-Photon States
VL - 4
ER -
TY - BOOK
AU - Ribbat, Christoph
ID - 44080
TI - Breathing in Manhattan: Carola Speads - The German Jewish Gymnastics Instructor Who Brought Mindfulness to America
ER -
TY - CONF
AB - The nonlinear optical response of quantum well excitons is investigated experimentally using polarization resolved four wave mixing, optical-pump optical-probe, and optical-pump Terahertz-probe spectroscopy. The four-wave mixing data reveal clear signatures of coherent biexcitons which concur with straight-forward polarization selection rules at the Γ point. The type-I samples show the well-established time-domain beating signatures in the transients as well as the corresponding spectral signatures clearly. The latter are also present in type-II samples; however, the smaller exciton and biexciton binding energies in these structures infer longer beating times which, in turn, are accompanied by faster dephasing of the type-II exciton coherences. Furthermore, the THz absorption following spectrally narrow, picosecond excitation at energies in the vicinity of the 1s exciton resonance are discussed. Here, the optical signatures yield the well-established redshifts and blueshifts for the appropriate polarization geometries in type-I quantum well samples also termed “AC Stark Effect”. The THz probe reveals intriguing spectral features which can be ascribed to coherent negative absorption following an excitation into a virtual state for an excitation below the 1s exciton resonance. Furthermore, the scattering and ionization of excitons is discussed for several excitation geometries yielding control rules for elastic and inelastic quasiparticle collisions.
AU - Meier, Torsten
AU - Stein, M.
AU - Schäfer, F.
AU - Anders, D.
AU - Littmann, J. H.
AU - Fey, M.
AU - Trautmann, Alexander
AU - Ngo, C.
AU - Steiner, J. T.
AU - Reichelt, Matthias
AU - Fuchs, C.
AU - Volz, K.
AU - Chatterjee, S.
ID - 43189
T2 - Ultrafast Phenomena and Nanophotonics XXVII
TI - Experimental studies of the excitonic nonlinear response of GaAs-based type-I and type-II quantum well structures interacting with optical and terahertz fields
VL - 12419
ER -
TY - CONF
AB - Anomalous currents refer to electronic currents that flow perpendicularly to the direction of the accelerating electric field. Such anomalous currents can be generated when Terahertz fields are applied after an optical interband excitation of GaAs quantum wells. The underlying processes are investigated by numerical solutions of the semiconductor Bloch equations in the length gauge. Excitonic effects are included by treating the manybody Coulomb interaction in time-dependent Hartree-Fock approximation and additionally also carrier-phonon scattering processes are considered. The band structure and matrix elements are obtained from a 14-band k · p model within the envelope function approximation. The random phase factors of the matrix elements that appear due to the separate numerical diagonalization at each k-point are treated by applying a smooth gauge transformation. We present the macroscopic Berry curvature and anomalous current transients with and without excitonic effects. It is demonstrated that the resonant optical excitation of excitonic resonances can significantly enhance the Berry curvature and the anomalous currents.
AU - Meier, Torsten
AU - Ngo, C.
AU - Priyadarshi, S.
AU - Duc, H. T.
AU - Bieler, M.
ID - 43191
T2 - Ultrafast Phenomena and Nanophotonics XXVII
TI - Terahertz-induced anomalous currents following the optical excitation of excitons in semiconductor quantum wells
VL - 12419
ER -
TY - CONF
AB - The nonlinear optical response of quantum well excitons excited by optical fields is analyzed by numerical solutions of the semiconductor Bloch equations. Differential absorption spectra are computed for resonant pumping at the exciton resonance and the dependence of the absorption changes on the polarization directions of the pump and probe pulses is investigated. Coherent biexcitonic many-body correlations are included in our approach up to third-order in the optical fields. Results are presented for spatially-direct type-I and spatiallyindirect type-II quantum well systems. Due to the spatial inhomogeneity, in type-II structures a finite coupling between excitons of opposite spins exists already on the Hartree-Fock level and contributes to the absorption changes for the case of opposite circularly polarized pump and probe pulses.
AU - Meier, Torsten
AU - Trautmann, Alexander
AU - Stein, M.
AU - Schäfer, F.
AU - Anders, D.
AU - Ngo, C.
AU - Steiner, J. T.
AU - Reichelt, Matthias
AU - Chatterjee, S.
ID - 43190
T2 - Ultrafast Phenomena and Nanophotonics XXVII
TI - Analysis of the nonlinear optical response of excitons in type-I and type-II quantum wells including many-body correlations
VL - 12419
ER -
TY - JOUR
AU - Meier, Torsten
AU - Schäfer, F.
AU - Stein, M.
AU - Lorenz, J.
AU - Dobener, F.
AU - Ngo, C.
AU - Steiner, J. T.
AU - Fuchs, C.
AU - Stolz, W.
AU - Volz, K.
AU - Hader, J.
AU - Moloney, J.V.
AU - Koch, S.W.
AU - Chatterjee, S.
ID - 43139
IS - 8
JF - Applied Physics Letters
TI - Gain recovery dynamics in active type-II semiconductor heterostructures
VL - 122
ER -
TY - GEN
AU - Meier, Torsten
AU - Grisard, S.
AU - Trifonov, A.V.
AU - Rose, Hendrik
AU - Reichhardt, R.
AU - Reichelt, Matthias
AU - Schneider, C.
AU - Kamp, M.
AU - Höfling, S.
AU - Bayer, M.
AU - Akimov, I.A
ID - 43132
T2 - arxiv:2302.02480
TI - Temporal sorting of optical multi-wave-mixing processes in semiconductor quantum dots
ER -
TY - JOUR
AU - Sperling, Jan
AU - Agudelo, Elizabeth
ID - 44050
IS - 4
JF - Physical Review A
SN - 2469-9926
TI - Entanglement of particles versus entanglement of fields: Independent quantum resources
VL - 107
ER -
TY - JOUR
AU - Sperling, Jan
AU - Gianani, Ilaria
AU - Barbieri, Marco
AU - Agudelo, Elizabeth
ID - 40477
IS - 1
JF - Physical Review A
SN - 2469-9926
TI - Detector entanglement: Quasidistributions for Bell-state measurements
VL - 107
ER -
TY - JOUR
AU - Lüders, Carolin
AU - Pukrop, Matthias
AU - Barkhausen, Franziska
AU - Rozas, Elena
AU - Schneider, Christian
AU - Höfling, Sven
AU - Sperling, Jan
AU - Schumacher, Stefan
AU - Aßmann, Marc
ID - 42973
IS - 11
JF - Physical Review Letters
KW - General Physics and Astronomy
SN - 0031-9007
TI - Tracking Quantum Coherence in Polariton Condensates with Time-Resolved Tomography
VL - 130
ER -
TY - JOUR
AB - We study how competition between physicians affects the provision of medical care. In
our theoretical model, physicians are faced with a heterogeneous patient population, in which patients
systematically vary with regard to both their responsiveness to the provided quality of care and their
state of health. We test the behavioral predictions derived from this model in a controlled laboratory
experiment. In line with the model, we observe that competition significantly improves patient benefits
as long as patients are able to respond to the quality provided. For those patients, who are not able
to choose a physician, competition even decreases the patient benefit compared to a situation without
competition. This decrease is in contrast to our theoretical prediction implying no change in benefits for
passive patients. Deviations from patient-optimal treatment are highest for passive patients in need of
a low quantity of medical services. With repetition, both, the positive effects of competition for active
patients as well as the negative effects of competition for passive patients become more pronounced. Our
results imply that competition can not only improve but also worsen patient outcome and that patients’
responsiveness to quality is decisive.
AU - Brosig-Koch, Jeannette
AU - Hehenkamp, Burkhard
AU - Kokot, Johanna
ID - 44092
JF - Health Economics
KW - physician competition
KW - patient characteristics
KW - heterogeneity in quality responses
KW - fee-for-service
KW - laboratory experiment
TI - Who benefits from quality competition in health care? A theory and a laboratory experiment on the relevance of patient characteristics
ER -
TY - GEN
AB - We consider a model where for-profit providers compete in quality in a price-regulated market that has been opened to competition, and where the incumbent is located at the center of the market, facing high costs of relocation. The model is relevant in markets such as public health care, education and schooling, or postal services. We find that, when the regulated price is low or intermediate, the entrant strategically locates towards the corner of the market to keep the incumbent at the low monopoly quality level. For a high price, the entrant locates at the corner of the market and both providers implement higher quality compared to a monopoly. In any case, the entrant implements higher quality than the incumbent provider. Social welfare is always higher in a duopoly if the cost of quality is low. For higher cost levels welfare is non-monotonic in the price and it can be optimal to the regulator not to use its entire budget. Therefore, the welfare effect of entry depends on the price and the size of the entry cost, and the regulator should condition the decision to allow entry on an assessment of the entry cost.
AU - Hehenkamp, Burkhard
AU - Kaarbøe, Oddvar M.
ID - 44093
KW - Quality competition
KW - Price regulation
KW - Location choice
KW - Product differentiation
TI - Price Regulation, Quality Competition and Location Choice with Costly Relocation
ER -
TY - JOUR
AB - We present strong enhancement of third harmonic generation in an amorphous silicon metasurface consisting of elliptical nano resonators. We show that this enhancement originates from a new type of multi-mode Fano mechanism. These ‘Super-Fano’ resonances are investigated numerically in great detail using full-wave simulations. The theoretically predicted behavior of the metasurface is experimentally verified by linear and nonlinear transmission spectroscopy. Moreover, quantitative nonlinear measurements are performed, in which an absolute conversion efficiency as high as ηmax ≈ 2.8 × 10−7 a peak power intensity of 1.2 GW cm−2 is found. Compared to an unpatterned silicon film of the same thickness amplification factors of up to ~900 are demonstrated. Our results pave the way to exploiting a strong Fano-type multi-mode coupling in metasurfaces for high THG in potential applications.
AU - Hähnel, David
AU - Golla, Christian
AU - Albert, Maximilian
AU - Zentgraf, Thomas
AU - Myroshnychenko, Viktor
AU - Förstner, Jens
AU - Meier, Cedrik
ID - 44097
IS - 1
JF - Light: Science & Applications
KW - tet_topic_meta
SN - 2047-7538
TI - A multi-mode super-fano mechanism for enhanced third harmonic generation in silicon metasurfaces
VL - 12
ER -
TY - JOUR
AU - Maack, Marten
ID - 44077
IS - 3
JF - Operations Research Letters
KW - Applied Mathematics
KW - Industrial and Manufacturing Engineering
KW - Management Science and Operations Research
KW - Software
SN - 0167-6377
TI - Online load balancing on uniform machines with limited migration
VL - 51
ER -
TY - GEN
AU - Mamedov, Tural
AU - Schleicher, Eckhard
AU - Schubert, Markus
AU - Ehlert, Thomas
AU - Kenig, Eugeny Y.
AU - Hampel, Uwe
ID - 44096
TI - Experimental analysis of ship motion effects on the performance of an absorption column equipped with structured packings
ER -
TY - GEN
AU - Ehlert, Thomas
AU - Mamedov, Tural
AU - Schubert, Markus
AU - Kenig, Eugeny Y.
ID - 44094
TI - Charakterisierung des Einflusses neigungsinduzierter Strömungsformen mit dem Ansatz der hydrodynamsichen Analogie
ER -
TY - GEN
AU - Ehlert, Thomas
AU - Lutters, Nicole
AU - Kenig, Eugeny Y.
ID - 44095
TI - Modellierung des Randspalts in Strukturpackungskolonnen mit dem Ansatz der hydrodynamischen Analogien
ER -
TY - JOUR
AU - Jende, Yvonne Kristin
ID - 44137
JF - Zeitschrift für Kanada-Studien
SN - 0944-7008
TI - "The Future of Canadian Studies: On Plowing a Lonely Furrow."
VL - 43
ER -
TY - BOOK
AU - Bauer, Anna Brigitte
ID - 44083
SN - 978-3-8325-5625-9
TI - Experimentelle Kompetenz Physikstudierender. Entwicklung und erste Erprobung eines performanzorientierten Kompetenzstrukturmodells unter Nutzung qualitativer Methoden
VL - 352
ER -
TY - GEN
AU - Beule, Felix
AU - Schmelzle, Lars
AU - Teutenberg, Dominik
AU - Possart, Gunnar
AU - Meschut, Gerson
AU - Mergheim, Julia
ID - 44181
T2 - 23. Kolloquium: Gemeinsame Forschung in der Klebtechnik
TI - Methodenentwicklung zur Simulation von hyperelastischen Klebverbindungen unter Crashbelastung
ER -
TY - GEN
AU - Schürmann, Patrick
ID - 43374
TI - A Formal Comparison of Advanced Digital Signature Primitives
ER -
TY - CONF
AU - Kowatz, Jannik
AU - Teutenberg, Dominik
AU - Meschut, Gerson
ID - 44183
T2 - 23. Kolloquium Gemeinsame Forschung in der Klebtechnik
TI - Weiterentwicklung der induktiven Schnellhärtung von Klebverbindungen für robuste Fertigungsprozesse unter Berücksichtigung von serienrelevanten Einflussfaktoren
ER -
TY - JOUR
AB - Microcellular wood fiber reinforced polymers offer the possibility to reduce the use of fossil raw materials. In particular, thick-walled structures with thicknesses greater than 6 mm offer a high potential for weight savings. This study investigates the cell structures and mechanical properties of injection-molded test specimens. The influence of different thicknesses (6–10 mm) along with different chemical blowing agents (endothermic, exothermic) with varying dosages (0–2 wt%) is analyzed. The investigations reveal that exothermic chemical blowing agents form finer cells consistently to thin-walled structures than endothermic ones. Higher foaming agent content leads to higher pore fractions, with many small cells coalescing into a large open-pore cell network. The mechanical properties depend mainly on the pore content of the sample. The specific tensile properties deteriorate with the use of chemical blowing agents (CFA), whereas the sandwich structure produced with compact edge layers has a positive influence on the specific flexural properties.
AU - Moritzer, Elmar
AU - Flachmann, Felix
ID - 42515
IS - 3
JF - Journal of Cellular Plastics
KW - Materials Chemistry
KW - Polymers and Plastics
KW - General Chemistry
SN - 0021-955X
TI - Morphological and mechanical properties of foamed thick-walled Wood-Plastic-Composite structures
VL - 59
ER -
TY - JOUR
AU - Burmeister, Sascha Christian
AU - Schryen, Guido
ID - 42179
JF - Energy Systems
TI - Distribution Network Optimization: Predicting computation times to design scenario analysis for network operators
ER -
TY - CONF
AB - Abstract. Friction-spinning as an innovative incremental forming process enables large degrees of deformation in tube and sheet metal-forming due to a self-induced heat generation in the forming zone. This paper presents new process designs for energy and resource-efficient forming of gas cylinders by friction-spinning without the use of an external heat supply. The self-generated heat enables friction-spinning process to reduce the energy demand in the manufacture of gas cylinders, which are usually manufactured with external heat (mostly fossil fuels), by 95 %. Typical gas cylinder contours, such as flattened and spherical bottom ends and cylinder necks, are manufactured by friction-spinning of AW 6060 tubular profiles with specifically designed tool path strategies. It is shown that friction-spinning enables the manufacture of typical gas cylinder contours with sufficient wall thickness and the required gas tightness without the input of external heat. Thus, this process can contribute to an increase in the energy and resource efficiency of forming processes.
AU - Dahms, Frederik
AU - Homberg, Werner
ID - 44035
SN - 2474-395X
T2 - Materials Research Proceedings
TI - Energy and Resource-efficient Forming of Gas Cylinders by Friction-Spinning
ER -
TY - JOUR
AB - The technical importance of paraffins as phase change materials (PCM) in heat storage systems increases. Knowledge on the thermal conductivity of paraffins is necessary for the design and optimization of heat storage systems. However, for most paraffins solely the thermal conductivity of the liquid state has been sufficiently investigated. For the solid state, precise thermal conductivity data are only known for a few paraffins, while only generalized values are available for the remainder, some of which contradict each other. In this study, a measurement setup based on the modified guarded hot plate method is developed. It is used to investigate the thermal conductivity of several paraffines in the solid state, including pure n-docosane and its compounds with different types and concentrations of graphite. For n-docosane in the solid state, the thermal conductivity is determined to be 0.49 W/(m K). A particle size of 200 μm with a spherical shape turns out to be optimal to increase the thermal conductivity. This allows the thermal conductivity of a compound with 10% graphite to increase by a factor of three compared to the pure paraffin. Furthermore, significant differences to thermal conductivity data from the literature are found.
AU - Paul, Andreas
AU - Baumhögger, Elmar
AU - Dewerth, Mats-Ole
AU - Hami Dindar, Iman
AU - Sonnenrein, Gerrit
AU - Vrabec, Jadran
ID - 43391
JF - Journal of Thermal Analysis and Calorimetry
KW - Physical and Theoretical Chemistry
KW - Condensed Matter Physics
SN - 1388-6150
TI - Thermal conductivity of solid paraffins and several n-docosane compounds with graphite
ER -
TY - CONF
AB - Die für die Berechnung des Energieeffizienzindex von Haushaltskältegeräten benötigten Parameter werden durch Norm-Messungen im Neuzustand der Geräte bestimmt. Aus früheren Untersuchungen ist bekannt, dass durch verschiedene technische Alterungsmechanismen der Energieverbrauch über eine Produktlebensdauer von 18 Jahren um bis zu 33 % zunehmen kann. Ziel des vom BMWi geförderten Projekts ALGE war es, die verschie-denen Ursachen und Einflussgrößen für die Alterung von Haushaltskältegeräten zu ermitteln und eine Alterungs-funktion zu bestimmen, die den zeitlichen Verlauf des zunehmenden Energieverbrauchs beschreibt.
In diesem Projekt wurde das Alterungsverhalten von Haushaltskältegeräten durch 100 Normenergieverbrauchs-messungen an 32 real gealterten Geräten untersucht. Aus den gewonnenen Ergebnissen konnte eine Alterungs-funktion bestimmt werden, die den Anstieg des Energieverbrauchs beschreibt. Alle untersuchten Geräte wurden an der Universität Paderborn im Neuzustand vermessen und nach einer Laufzeit von bis zu 21 Jahren erneut geprüft. Bereits nach einem zweijährigen Betrieb konnte ein Mehrverbrauch von bis zu 11 % festgestellt werden. Über die durchschnittliche Produktlebensdauer von Haushaltskältegeräten von ca. 16 Jahren steigert sich der Energieverbrauch um durchschnittlich 27 %.
Im Rahmen des Projekts wurden verschiedene Systemkomponenten, wie Isolierung und Verdichter, hinsichtlich ihres Alterungsverhaltens untersucht. Bei dem im Gehäuse als Isolierung verwendeten PUR-Schaum konnte über einen Zeitraum von 31 Monaten ein Anstieg der Wärmeleitfähigkeit von 19,5 W/(m⋅K) auf 24,5 W/(m⋅K) festge-stellt werden. Zur Untersuchung der Alterung der Verdichter wurden zuvor auf einem Kalorimeterteststand ver-messene Verdichter in Geräte eingebaut. Nach einem zweijährigen Betrieb wurden diese Verdichter wieder aus-gebaut und erneut vermessen. Hierbei konnte keine Änderung des COP festgestellt werden. Zusätzlich zu den technischen Parametern wurde der Einfluss des Verbraucherverhaltens analysiert. Hier zeigte sich, dass bis zu 33 % des Gesamtenergieverbrauchs nach einer mehrjährigen Nutzungsdauer verbraucherinduziert sein können.
AU - Paul, Andreas
AU - Baumhögger, Elmar
AU - Elsner, Andreas
AU - Reineke, Michael
AU - Kasper, Tina
AU - Schumacher, Daniel
AU - Vrabec, Jadran
AU - Hüppe, Christian
AU - Stamminger, Rainer
AU - Hölscher, Heike
AU - Stoll, Ragnar
AU - Wagner, Hendrik
AU - Gries, Ulrich
AU - Becker, Wolfgang
ID - 43394
KW - Haushaltskältegeräte
KW - Energieverbrauch
KW - Alterung
KW - Verdichter
KW - PUR-Schaum
SN - 978-3-932715-55-6
TI - Alterungsmechanismen von Haushaltskältegeräten
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