• Entropy, black holes, and the new cyclic universe 

  Ijjas, Anna; Steinhardt, Paul J. (Amsterdam : North-Holland Publ., 2021)

  We track the evolution of entropy and black holes in a cyclic universe that undergoes repeated intervals of expansion followed by slow contraction and a smooth (non-singular) bounce. In this kind of cyclic scenario, there ...
• Discoloration of AISI 420 stainless steel in dependence of inter layer time during Laser-based Powder Bed Fusion 

  Wahl, Jan Philipp; Bernhard, Robert; Hermsdorf, Jörg; Kaierle, Stefan (Amsterdam [u.a.] : Elsevier, 2022)

  Parts built by laser-based powder bed fusion (PBF-LB) experience intervals of heating and cooling during the powder deposition and the selective melting of successive layers. Short time intervals of cooling can lead to ...
• Expert system-supported optimization of laser welding of additively manufactured thermoplastic components 

  Kuklik, Julian; Mente, Torben; Wippo, Verena; Jaeschke, Peter; Kaierle, Stefan; Overmeyer, Ludger (Amsterdam [u.a.] : Elsevier, 2022)

  Laser transmission welding (LTW) is a known technique to join conventionally produced thermoplastic parts, e.g. injected molded parts. When using LTW for additively manufactured parts (usually prototypes, small series), ...
• Design of additively manufacturable injection molds with conformal cooling 

  Wahl, Jan Philipp; Niedermeyer, Jens; Bernhard, Robert; Hermsdorf, Jörg; Kaierle, Stefan (Amsterdam [u.a.] : Elsevier, 2022)

  Additive manufacturing enables the production of intricate geometries including internal structures. This design freedom can be used advantageously to enhance heat transfer in injection molds by means of conformal cooling. ...
• Large-scale CO2 laser-based sol-gel annealing of titanium dioxide on borosilicate glass 

  Desens, Michael; Wesang, Kristin; Rettschlag, Katharina; Wermbter, Karsten; Jäschke, Peter; Overmeyer, Ludger; Kaierle, Stefan (Amsterdam [u.a.] : Elsevier, 2022)

  There are several ways to create optical filters on glass, such as the low-cost sol-gel coating. However, to make this process even more effective and flexible, a laser instead of a conventional furnace process was used ...
• CO2 laser based welding of borosilicate glass by Laser Glass Deposition 

  Sleiman, Khodor; Legutko, Martin; Rettschlag, Katharina; Jäschke, Peter; Overmeyer, Ludger; Kaierle, Stefan (Amsterdam [u.a.] : Elsevier, 2022)

  Due to its thermal and chemical resistance, borosilicate glass finds a wide range of applications in optics, chemical laboratories and in glass apparatus engineering. For the manufacturing of complex glass components, the ...
• Influence of laser spot oscillation parameters on the seam geometry and dilution in the LDNA process 

  Bokelmann, Tjorben; Lammers, Marius; Hermsdorf, Jörg; Emadmostoufi, Sobhan; Mokrov, Oleg; Sharma, Rahul; Reisgen, Uwe; Kaierle, Stefan (Amsterdam [u.a.] : Elsevier, 2022)

  The “Laser-assisted double wire with non-transferred arc surfacing process (LDNA)” is characterized by an electric arc burning between the filling wires. The molten filler material is fed to the substrate surface by gravity ...
• Investigations on the effect of post treatment utilizing ultrasonic standing waves on the hardness of laser beam welds in stainless steel 

  Grajczak, J.; Nowroth, C.; Long, Y.; Twiefel, J.; Wallaschek, J.; Nothdurft, S.; Hermsdorf, J.; Kaierle, S. (Amsterdam [u.a.] : Elsevier, 2022)

  Laser beam welding is precise, quick and highly automatable. Nevertheless, disadvantageous hardness profiles can result and promote cracking. By an ultrasonic post treatment, crystal defects, internal stress and grain ...
• Macroscopic simulation model for laser cutting of carbon fibre reinforced plastics 

  Keuntje, Jan; Mrzljak, Selim; Gerdes, Lars; Wippo, Verena; Kaierle, Stefan; Overmeyer, Ludger; Walther, Frank; Jaeschke, Peter (Amsterdam [u.a.] : Elsevier, 2022)

  Laser cutting of carbon fibre reinforced plastics (CFRP) has shown promising potential as an alternative to conventional manufacturing processes. Laser cutting has major benefits of contactless and therefore wear-free ...
• Influence of the laser position in laser-assisted WAAM process on weld bead shape and surface properties 

  Biester, Kai; Lammers, Marius; Hermsdorf, Jörg; Kaierle, Stefan (Amsterdam [u.a.] : Elsevier, 2022)

  The lateral use of the laser in laser-assisted WAAM processes, resulting in a directional dependence, can influence the bead shape and the bead surface. The influence of the laser position on the weld bead is investigated. ...
• Influence of an oxygen-free atmosphere on laser beam brazing of aluminium with prior surface deoxidation by pulsed laser radiation 

  Aman, Witali; Nothdurft, Sarah; Hermsdorf, Jörg; Kaierle, Stefan; Szafarska, Maik; Gustus, René; Maus-Friedrichs, Wolfgang; Overmeyer, Ludger (Amsterdam [u.a.] : Elsevier, 2022)

  Aluminium alloys, like AlMgSi1 and AlMg3, cannot be joined in industrial processes by laser beam brazing without the use of fluxes due to their resistant oxide layer. The aim of this study is to dispense with the use of ...
• Advances in powder bed based Additive Manufacturing of metal-glass-hybrid-components 

  Abel, Arvid; Sayilgan, Vurgun; Bernhard, Robert; Hermsdorf, Jörg; Kaierle, Stefan; Overmeyer, Ludger (Amsterdam [u.a.] : Elsevier, 2022)

  As powder bed based additive manufacturing (AM) is gaining more traction in the research and industry, significant efforts are made to expand the capability of AM in combining different materials. Conventionally, multiple ...
• Determination of optimum process parameters for different Ti-6Al-4V powders processed by Laser-based Powder Bed Fusion 

  Emminghaus, Nicole; Bernhard, Robert; Hermsdorf, Jörg; Kaierle, Stefan (Amsterdam [u.a.] : Elsevier, 2022)

  The PBF-LB (laser-based powder bed fusion) process is subject to a large number of variables, including the characteristics of the processed powder. Since a powder with a given specification can be supplied by various ...
• Probing horizon scale quantum effects with Love 

  Datta, Sayak (Bristol : IOP Publ., 2022)

  Future gravitational wave (GW) detectors have been projected to be able to probe the nature of compact objects in great detail. In this work, we study the potential observability of the small length scale physics near black ...
• Nd:YVO4 high-power master oscillator power amplifier laser system for second-generation gravitational wave detectors 

  Thies, Fabian; Bode, Nina; Oppermann, Patrick; Frede, Maik; Schulz, Bastian; Willke, Benno (Washington, DC : Soc., 2019)

  Ultrastable high-power laser systems are essential components of the long baseline interferometers that detected the first gravitational waves from merging black holes and neutron stars. One way to further increase the ...
• Experimental application of a laser-based manufacturing process to develop a free customizable, scalable thermoelectric generator demonstrated on a hot shaft 

  Abt, Marvin; Kruppa, Katharina; Wolf, Mario; Feldhoff, Armin; Overmeyer, Ludger (Hoboken, NJ : Wiley, 2022)

  Geometry, design, and processing in addition to the thermoelectric material properties have a significant influence on the economic efficiency and performance of thermoelectric generators (TEGs). While conventional BULK ...
• The equivalence and/or the effacing principle in f(R) theories of gravity 

  Bhattacharyya, Soham (Berlin ; Heidelberg : Springer, 2022)

  The Einstein–Hilbert action of the general theory of relativity (GR) is the integral of the scalar curvature R. It is a theory that is drawn from the Equivalence principle and has predictions that come out as a consequence ...
• Combination of Laser and Thermal Sintering of Thermoelectric Ca3Co4O9 Films 

  Wolf, Mario; Rehder, Lena; Steinbach, Frank; Abt, Marvin; Hinterding, Richard; Overmeyer, Ludger; Feldhoff, Armin (Weinheim : Wiley-VCH Verl., 2021)

  The manufacturing technology of thermoelectric materials is laborious and expensive often including complex and time-intensive preparation steps. In this work, a laser sintering process of the oxide-based thermoelectric ...
• Constraints on r-modes and Mountains on Millisecond Neutron Stars in Binary Systems 

  Covas, P.B.; Papa, M.A.; Prix, R.; Owen, B.J. (London : Institute of Physics Publ., 2022)

  Continuous gravitational waves are nearly monochromatic signals emitted by asymmetries in rotating neutron stars. These signals have not yet been detected. Deep all-sky searches for continuous gravitational waves from ...
• Is the Black-widow Pulsar PSR J1555-2908 in a Hierarchical Triple System? 

  Nieder, L.; Kerr, M.; Clark, C.J.; Bruel, P.; Cromartie, H.T.; Ransom, S.M.; Ray, P.S. (London : Institute of Physics Publ., 2022)

  The 559 Hz black-widow pulsar PSR J1555-2908, originally discovered in radio, is also a bright gamma-ray pulsar. Timing its pulsations using 12 yr of Fermi-Large Area Telescope gamma-ray data reveals long-term variations ...

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