@article{HartmannFischerSeidel, author = {Hartmann, J{\"u}rgen and Fischer, J. and Seidel, J.}, title = {A non-contact technique providing improved accuracy in area measurements of radiometric apertures}, series = {Metrologia}, journal = {Metrologia}, number = {37}, pages = {637 -- 640}, language = {en} } @article{HartmannWerner, author = {Hartmann, J{\"u}rgen and Werner, L.}, title = {Calibration and interpolation of the spectral responsivity of silicon photodiode based detectors}, series = {Sensors \& Actuators A: Physical}, journal = {Sensors \& Actuators A: Physical}, number = {156}, pages = {185 -- 190}, language = {en} } @article{HartmannKlotzbuecherReichling, author = {Hartmann, J{\"u}rgen and Klotzb{\"u}cher, T. and Reichling, M.}, title = {Local variation of room temperature thermal conductivity in high quality polycrystalline diamond}, series = {Appl. Phys. Lett.}, journal = {Appl. Phys. Lett.}, number = {73}, pages = {756 -- 758}, language = {en} } @article{HartmannCostelloReichling, author = {Hartmann, J{\"u}rgen and Costello, M. and Reichling, M.}, title = {The influence of thermal barriers on heat flow in high quality chemical vapour deposited diamond}, series = {Phys. Rev. Lett.}, journal = {Phys. Rev. Lett.}, number = {80}, pages = {117 -- 120}, language = {en} } @incollection{HartmannBernhard, author = {Hartmann, J{\"u}rgen and Bernhard, Frank}, title = {Strahlungsthermometrie}, series = {Technische Temperaturmessung}, booktitle = {Technische Temperaturmessung}, editor = {Bernhard, Frank}, edition = {2}, publisher = {Springer}, isbn = {ISBN 978-3-642-24505-3}, language = {de} } @article{HartmannVerhoevenReichlingetal., author = {Hartmann, J{\"u}rgen and Verhoeven, H. and Reichling, M. and M{\"u}ller-Sebert, W. and Zachai, R.}, title = {Structural limitations to local thermal diffusivity of diamond films}, series = {Diamond and Related Materials}, journal = {Diamond and Related Materials}, number = {5}, pages = {1012 -- 1016}, language = {en} } @article{HartmannMaznevReichling, author = {Hartmann, J{\"u}rgen and Maznev, A.A. and Reichling, M.}, title = {Thermal wave propagation in thin films on substrates}, series = {J. Appl. Phys}, journal = {J. Appl. Phys}, number = {78}, pages = {5266 -- 5269}, language = {en} } @article{HartmannLangerReichling, author = {Hartmann, J{\"u}rgen and Langer, G. and Reichling, M.}, title = {Thermal conductivity of thin metallic films measured with the photothermal profile analysis}, series = {Rev. Sci. Instr.}, journal = {Rev. Sci. Instr.}, number = {68}, pages = {1510 -- 1513}, language = {en} } @article{HartmannReichlingVoigt, author = {Hartmann, J{\"u}rgen and Reichling, M. and Voigt, P.}, title = {Quantitative thermal imaging of current densities and heat flow in electronic microstructures}, series = {Prog. in Nat. Sci.}, journal = {Prog. in Nat. Sci.}, number = {6}, pages = {519 -- 523}, language = {en} } @article{HartmannReichlingMatthias, author = {Hartmann, J{\"u}rgen and Reichling, M. and Matthias, E.}, title = {Thermoreflectance measurements of single thermal barriers in CVD-diamond}, series = {Prog. in Nat. Sci.}, journal = {Prog. in Nat. Sci.}, number = {6}, pages = {297 -- 300}, language = {en} } @article{HartmannVoigtReichlingetal., author = {Hartmann, J{\"u}rgen and Voigt, P. and Reichling, M. and Matthias, E.}, title = {Photothermal measurement of thermal anisotropy in pyrolytic graphite}, series = {Appl. Phys. B}, journal = {Appl. Phys. B}, number = {62}, pages = {493 -- 497}, language = {en} } @article{HartmannVoigtReichling, author = {Hartmann, J{\"u}rgen and Voigt, P. and Reichling, M.}, title = {Thermal wave imaging of electrically heated microstructures}, series = {J. Appl. Phys.}, journal = {J. Appl. Phys.}, number = {80}, pages = {2013 -- 2018}, language = {en} } @inproceedings{HartmannManaraZipfetal., author = {Hartmann, J{\"u}rgen and Manara, Jochen and Zipf, Matthias and Stark, Thomas and Arduini, Mariacarla and Ebert, Hans-Peter and Tutschke, Andreas and Hallam, Andrew and Hanspal, Jagdevinder and Langley, Mark and Hodge, D.}, title = {Development of Long Wavelength Infrared Radiation Thermometry for Measurements in Gas Turbines}, address = {Darmstadt}, language = {en} } @inproceedings{HartmannMachinBloembergenetal., author = {Hartmann, J{\"u}rgen and Machin, Graham and Bloembergen, P. and Anhalt, Klaus and Sadli, M. and Saunders, P. and Woolliams, E. and Yamada, Y. and Yoon, H.}, title = {Practical implementation of the mise-en-prtique for the definition of the Kelvin above the silver point}, address = {Portroz (Slowenien)}, language = {en} } @inproceedings{HartmannKnoppLenskietal., author = {Hartmann, J{\"u}rgen and Knopp, Kevin and Lenski, Philipp and Z{\"a}nglein, Marc and Manara, Jochen and Stark, Thomas and Zipf, Matthias and Arduini, Mariacarla and Schreiber, Ekkehard and Kr{\"u}ger, U. and Schmidt, Franz and Brunner, Martin}, title = {Sensor systems for additive manufacturing}, publisher = {Key Note Lecture MSE 2018}, address = {Darmstadt}, language = {en} } @incollection{HartmannReichling, author = {Hartmann, J{\"u}rgen and Reichling, M.}, title = {Thermal characterization of diamond materials}, series = {Properties and growth of diamond}, booktitle = {Properties and growth of diamond}, editor = {Nazar{\´e}, H. and Neves, A.J.}, publisher = {Institution of Electrical Engineers}, address = {London}, language = {en} } @inproceedings{ZinkDotterweichHartmannetal., author = {Zink, Markus H. and Dotterweich, C. and Hartmann, J{\"u}rgen and Harrer, S. and Hemberger, F. and Ebert, Hans-Peter and Schnitzler, Tim}, title = {Phase Change Materials for Use in Thermally and Electrically Stressed Insulation for High Voltage Applications}, series = {IEEE Electrical Insulation Conference}, volume = {2016}, booktitle = {IEEE Electrical Insulation Conference}, pages = {605 -- 608}, language = {en} } @inproceedings{HartmannAnhaltHollandtetal., author = {Hartmann, J{\"u}rgen and Anhalt, Klaus and Hollandt, J{\"o}rg and Taubert, Dieter Richard and Werner, L.}, title = {Optische Hochtemperaturmesstechnik f{\"u}r die Thermometrie, Radiometrie und Photometrie}, address = {N{\"u}rnberg}, language = {en} } @inproceedings{HartmannOchsLenskietal., author = {Hartmann, J{\"u}rgen and Ochs, Dennis and Lenski, Philipp and Schiffler, Andreas and Versch, Alexander and Manara, Jochen}, title = {Thermal process monitoring for additive manufacturing}, address = {Darmstadt}, language = {en} } @article{HartmannNilssonFricke, author = {Hartmann, J{\"u}rgen and Nilsson, O. and Fricke, J.}, title = {Thermal diffusivity measurements on two-layered systems with the laser-flash method}, series = {High Temp. - High Press}, journal = {High Temp. - High Press}, number = {25}, pages = {403 -- 410}, language = {en} } @article{OchsWehnertHartmannetal., author = {Ochs, Dennis and Wehnert, Kira-Kristin and Hartmann, J{\"u}rgen and Schiffler, Andreas and Schmitt, Jan}, title = {Sustainable Aspects of a Metal Printing Process Chain with Laser Powder Bed Fusion (LPBF)}, series = {Procedia CIRP}, volume = {98}, journal = {Procedia CIRP}, publisher = {Elsevir}, pages = {613 -- 618}, abstract = {Production companies are getting more and more aware of the relevancy of energy costs and the environmental impact of their manufactured products. Hence, the knowledge about the energy intensity of new process technologies as metal printing becomes increasingly crucial. Therefore, data about the energy intensity of entire process chains allow a detailed assessment of the life cycle costs and environmental impact of metal printed parts. As metal printing with Laser Powder Bed Fusion (LPBF) is applied from rapid prototyping to serial manufacturing processes more and more, sustainability data are useful to support a valid scale-up scenario and energetic improvements of the 3D-printing machinery as well as peripheral aggregates used in the process chain. The contribution aims to increase the transparency of the LPBF process chain in terms of its energy consumption. Therefore a generalized model to assess sustainability aspects of metal printed parts is derived. For this purpose, the LPBF process chain with the essential pre-, main- and post-processes is evaluated regarding its energy intensity. Here, the sub-processes, for example wet and dry cleaning of the printer, sieving of the metal powder or sand-blasting of the part are analyzed as well as the main printing process. Based on the derived experimental data from an installed, industry-like process chain, a model is created, which tends to generalize the experimental findings to evaluate other metal printed parts and process chain variants in terms of their energy intensity.}, language = {en} } @inproceedings{HartmannLenskiOchsetal., author = {Hartmann, J{\"u}rgen and Lenski, Philipp and Ochs, Dennis and Shandy, Amir and Winterstein, A. and Versch, Alexander and Schiffler, Andreas}, title = {Thermische Prozess{\"u}berwachung f{\"u}r additive Fertigungsverfahren}, address = {Berlin}, language = {de} } @inproceedings{HartmannDzemkoEngelmannetal., author = {Hartmann, J{\"u}rgen and Dzemko, Mikita and Engelmann, Bastian and Schmitt, Jan}, title = {Toward Shifted Production Strategies Through Additive Manufacturing: A Technology and Market Review for Changing Value Chains}, series = {7th CIRP Global Web Conference (86)}, volume = {86}, booktitle = {7th CIRP Global Web Conference (86)}, doi = {10.1016/j.procir.2020.01.029}, pages = {228 -- 233}, abstract = {In the last decade many different additive manufacturing (AM) technologies for metal, plastic or ceramic processing raise from research to commercialization. As a result, AM grows into different business areas and transforms structures and processes. Hence, the contribution tends to show the change in added values though the availability of different additive manufacturing technologies based on a technology screening and market research. Regarding the named purpose, a broad market research of 83 companies and 339 printer models has been conducted to find patterns of AM technology market share and regions to structure indicators such as accuracy by processed material classes with a specified AM method. Printing materials as metal, plastic, ceramic and carbon have been considered. The categorization is done by the AM principles: power bed fusion, material extrusion, vat photopolymerization and …}, language = {en} } @inproceedings{HartmannManaraZipfetal., author = {Hartmann, J{\"u}rgen and Manara, Jochen and Zipf, Mathias and Stark, Thomas and Knopp, Kevin and Z{\"a}nglein, Marc and Lenski, Philipp and Schreiber, Ekkehard and Schmidt, Franz and Brunner, Martin and M{\"u}ller, Michael}, title = {Thermophysical property measurements at high-temperatures for power engineering and additive manufacturing processes}, address = {Berlin}, isbn = {978-3-940283-94-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-17678}, pages = {6}, abstract = {To address the needs for increasing efficiency in power conversion, stratified structures like thermal barrier coatings, are used to increase operation temperature. Also advanced material processing like 3D laser printing of metals and ceramics are based on a layer-to-layer process at high temperatures, resulting in non-homogeneous components. Both systems require more and more detailed investigation methods to characterise the material properties of the resulting structures and to optimize the relevant processes. To address the required needs in advanced material characterisation recently an attempt was started to develop a unique measurement set-up for advanced material characterisation. This method is based on the well know laser flash principle, which was improved by adding supplementary heating sources and additional detection channels. Combining different heating mechanism and heating times with the two-dimensional measuring of the thermal flow across the sample enables the determination of different opto-thermal parameters and other material properties, e.g. mechanical contact, electrical conductivity or optical data, which also depend on or affect the flow of heat. In this paper we describe the implementation of the different optical methods to measure the thermal heat flow by point-like and two-dimensional temperature measurement and present first results on several samples.}, language = {en} } @article{KnoppShandyManaraetal., author = {Knopp, Kevin and Shandy, Amir and Manara, Jochen and Vidi, Stephan and Hartmann, J{\"u}rgen}, title = {Metrologische Apparaturen zur Messung thermophysikalischer Materialeigenschaften bei sehr hohen Temperaturen im EU-Projekt Hi-TRACE}, series = {FHWS Science Journal}, volume = {5}, journal = {FHWS Science Journal}, number = {2}, issn = {2196-6095}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-20046}, pages = {83 -- 92}, abstract = {Industriezweige wie die Glas-Industrie, die Kraftwerkstechnik sowie die Luft- und Raumfahrttechnik m{\"u}ssen kontinuierlich neue Methoden entwickeln, sowie bestehende Verfahren optimieren, um in ihren Bereichen wettbewerbsf{\"a}hig zu sein bzw. neue Anforderungen an Umwelt- und Klimaschutz zu erf{\"u}llen. Dies beinhaltet oft die Entwicklung neuer Materialien, die leichter zu fabrizieren sind und sowohl mechanisch als auch thermisch h{\"o}heren Belastungen standhalten. F{\"u}r die genannten Industriezweige sind Prozesse mit hohen Betriebstemperaturen bis zu 3.000 °C kennzeichnend und damit ist die Kenntnis von Materialeigenschaften bei diesen extremen Temperaturen von großer Bedeutung. Auch wenn es bereits einige Messapparaturen f{\"u}r die Bestimmung von thermophysikalischen Materialdaten bei hohen Temperaturen gibt, muss die R{\"u}ckf{\"u}hrung dieser auf die SI Basiseinheiten gew{\"a}hrleistet werden, um die Zuverl{\"a}ssigkeit der gemessenen Daten f{\"u}r die Anforderung der genannten Branchen sicherzustellen. Diese Aufgabe ist das Ziel des EMPIR-(European Metrology Programme for Innovation and Research) Projektes Hi-TRACE [1]. Hi-TRACE zielt darauf ab, Referenzapparaturen und neue Methoden f{\"u}r die Messung von thermophysikalischen Materialeigenschaften, (thermische Diffusivit{\"a}t, spezifische W{\"a}rme, Emissionsgrad und Schmelztemperatur) sowie der Haftung von Schichten {\"u}ber 1.000 °C zu bestimmen.}, language = {de} } @article{OchsWehnertKnoppetal., author = {Ochs, Dennis and Wehnert, Kira-Kristin and Knopp, Kevin and Hartmann, J{\"u}rgen and Versch, Alexander and Schiffler, Andreas}, title = {Untersuchungen zur Temperaturleitf{\"a}higkeit additiv gefertigter Stahlproben in Abh{\"a}ngigkeit der relativen Dichte}, series = {FHWS Science Journal}, volume = {5}, journal = {FHWS Science Journal}, number = {2}, issn = {2196-6095}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-19986}, pages = {75 -- 82}, abstract = {Das direkte Metall-Laser-Schmelzen (DMLS) aus der Familie der Additiven Fertigungsverfahren (AM) erm{\"o}glicht die schichtweise Erzeugung komplexer dreidimensionaler Geometrien mit hoher relativer Dichte unter Verwendung von Metallpulver als Ausgangsmaterial [1]. Die Technologie wird zunehmend eingesetzt, um innovative Bauteile material- und gewichtssparend herzustellen oder komplexe Produkte ohne zus{\"a}tzliche Werkzeuge oder Spannvorrichtungen zu fertigen. Dar{\"u}ber hinaus sind Funktionsintegrationen, zum Beispiel Gussformen mit eingepr{\"a}gten K{\"u}hlkan{\"a}len, m{\"o}glich. Da einzelne Metallpulverschichten auf vorhergehende Schichten aufgeschmolzen werden, entstehen w{\"a}hrend der Herstellung des Bauteils komplexe, zeitabh{\"a}ngige Temperaturprofile [2]. Durch den Einsatz hoher Laserintensit{\"a}ten und Scangeschwindigkeiten, bei denen die Belichtungszeit der Laserbestrahlung im Bereich von Millisekunden liegt, werden zudem extrem hohe Aufheiz- und Abk{\"u}hlraten induziert, die zu einzigartigen Mikrostrukturen und Materialeigenschaften f{\"u}hren [3]. Diese extremen Prozessbedingungen k{\"o}nnen sich jedoch auch negativ auf den Fertigungsprozess auswirken. Bei komplexen Bauteilen bleibt die Prozessstabilit{\"a}t und Qualit{\"a}tssicherung Umfragen zufolge weiterhin die wichtigste technologische Barriere f{\"u}r den Einsatz additiv gefertigter Bauteile in hochbelasteten oder sicherheitsrelevanten Bereichen [4]. Daher verspricht der Zusammenhang zwischen Temperaturprofil w{\"a}hrend der Fertigung, relativer Dichte der Bauteile, sowie thermophysikalischer Eigenschaften additiv gefertigter Proben wichtige Erkenntnisse, insbesondere im Hinblick auf eine zerst{\"o}rungsfreie Qualit{\"a}tssicherung, sowie neue Anwendungsm{\"o}glichkeiten.}, language = {de} } @article{JuergenArduiniManaraetal., author = {J{\"u}rgen, Hartmann and Arduini, Mariacarla and Manara, Jochen and Stark, Thomas and Ebert, Hans-Peter}, title = {Development and Evaluation of an Improved Apparatus for Measuring the Emissivity at High Temperatures}, series = {Sensors}, volume = {21}, journal = {Sensors}, number = {18}, issn = {1424-8220}, doi = {10.3390/s21186252}, abstract = {An improved apparatus for measuring the spectral directional emissivity in the wavelength range between 1 µm and 20 µm at temperatures up to 2400 K is presented in this paper. As a heating unit an inductor is used to warm up the specimen, as well as the blackbody reference to the specified temperatures. The heating unit is placed in a double-walled vacuum vessel. A defined temperature, as well as a homogenous temperature distribution of the whole surrounding is ensured by a heat transfer fluid flowing through the gap of the double-walled vessel. Additionally, the surrounding is coated with a high-emitting paint and serves as blackbody-like surrounding to ensure defined boundary conditions. For measuring the spectral directional emissivity at different emission angles, a movable mirror is installed in front of the specimen, which can be adjusted by a rotatable arrangement guiding the emitted radiation into the attached FTIR-spectrometer. The setup of the emissivity measurement apparatus (EMMA) and the measurement procedure are introduced, and the derived measurement results are presented. For evaluating the apparatus, measurements were performed on different materials. The determined emissivities agree well with values published in literature within the derived relative uncertainties below 4\% for most wavelengths.}, language = {en} } @article{HartmannLitorjaFowleretal., author = {Hartmann, J{\"u}rgen and Litorja, M. and Fowler, J. and Fox, N. and Stock, M. and Razet, A. and Khlevnoy, B. and Ikonen, E. and Machacs, M. and Doytchinov, K.}, title = {Final report on the CCPR-S2 supplementary comparison of area measurements of apertures for radiometry}, series = {Metrologia}, volume = {44}, journal = {Metrologia}, number = {02002}, language = {en} } @article{HartmannMoritzRothetal., author = {Hartmann, J{\"u}rgen and Moritz, W. and Roth, U. and Heyde, M. and Rademann, K. and Reichling, M.}, title = {Submicrosecond range surface heating and temperature measurement for efficient sensor reactivation}, series = {Thin Solid Films}, journal = {Thin Solid Films}, number = {391}, pages = {143 -- 148}, language = {en} }