@misc{HartmannEdler, author = {Hartmann, J{\"u}rgen and Edler, F.}, title = {Simultaneous contact and non-contact measurements of the melting temperature of a N-C fixed-point cell}, address = {Banf (Kanada)}, language = {en} } @inproceedings{HartmannTegeler, author = {Hartmann, J{\"u}rgen and Tegeler, E.}, title = {Activities in the field of legal metrology and standardisation of clinical thermometers}, address = {Dubrovnik (Kroatien)}, language = {en} } @inproceedings{HartmannWerner, author = {Hartmann, J{\"u}rgen and Werner, L.}, title = {Radiation thermometry towards the triple point of water?}, address = {Banf (Kanada)}, language = {en} } @inproceedings{HartmannBloembergenSasajimaetal., author = {Hartmann, J{\"u}rgen and Bloembergen, P. and Sasajima, N. and Yamada, Y.}, title = {Comparing alternative schemes for realizing the high-temperature part of a future ITS-20XX with the aid of metal-carbon eutectic fixed points}, address = {Chicago (USA)}, language = {en} } @inproceedings{HartmannReichlingMatthias, author = {Hartmann, J{\"u}rgen and Reichling, M. and Matthias, E.}, title = {Thermoreflectance measurements of single thermal barriers in CVD-Diamond}, address = {Nanjing (China)}, language = {en} } @inproceedings{HartmannEdlerAnhalt, author = {Hartmann, J{\"u}rgen and Edler, F. and Anhalt, Klaus}, title = {Novel fixed point cell design for simultaneous contact and non-contact temperature measurement}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, address = {Zagrep}, pages = {873 -- 878}, language = {en} } @inproceedings{GutschwagerSchillerHartmannetal., author = {Gutschwager, B. and Schiller, S. and Hartmann, J{\"u}rgen and Hollandt, K.}, title = {A lens-free InGaAs transfer radiation thermometer with an extended calibration range above 960 °C}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, address = {Zagrep}, pages = {605 -- 610}, language = {en} } @inproceedings{HartmannTaubertFriedrichetal., author = {Hartmann, J{\"u}rgen and Taubert, Dieter Richard and Friedrich, R. and Sperfeld, P. and Hollandt, J{\"o}rg}, title = {Long-Term Stability of the Spectral Responsivity of Filter Radiometers at the PTB}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, address = {Zagrep}, pages = {977 -- 982}, language = {en} } @inproceedings{HartmannTaubertFischer, author = {Hartmann, J{\"u}rgen and Taubert, Dieter Richard and Fischer, Joachim}, title = {Measurements of T-T90 down to Zinc point temperatures with absolute filter radiometry}, series = {Proceedings of Tempmeko 2001}, booktitle = {Proceedings of Tempmeko 2001}, editor = {Fellmuth, B. and Seidel, J. and Scholze, G.}, publisher = {VDI Verlag}, address = {Berlin}, pages = {377 -- 382}, language = {en} } @inproceedings{EdlerGorgievaHartmannetal., author = {Edler, F. and Gorgieva, M. and Hartmann, J{\"u}rgen and Wagner, M.}, title = {Comparison of different methods for the determination of undisturbed surface temperature}, series = {Proceedings of Tempmeko 2001}, booktitle = {Proceedings of Tempmeko 2001}, editor = {Fellmuth, B. and Seidel, J. and Scholze, G.}, publisher = {VDI Verlag}, address = {Berlin}, pages = {1105 -- 1110}, language = {en} } @inproceedings{HartmannReichling, author = {Hartmann, J{\"u}rgen and Reichling, M.}, title = {Complete characterisation of thermal heat transfer in high quality chemical vapour deposited diamond}, series = {Photoacoustic and Photothermal Phenomena}, booktitle = {Photoacoustic and Photothermal Phenomena}, editor = {Scudieri, F. and Bertolotti, M.}, address = {Woodbury (New York)}, pages = {295 -- 299}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {Investigation of the Accuracy of the ITS-90 with Reference to Thermodynamic Temperature in the Range from 400° C up to 600° C}, series = {AIP Conference Proceedings (684)}, booktitle = {AIP Conference Proceedings (684)}, publisher = {American Institute of Physics}, isbn = {0-7354-0153-5}, pages = {7 -- 12}, abstract = {For several years Physikalisch-Technische Bundesanstalt (PTB) has performed thermodynamic temperature measurements on a large area blackbody applying filter radiometers (FR) based on silicon photodiodes and interference filters with center wavelengths at 676 nm, 800 nm, 900 nm, and 1000 nm. These FRs were used for the determination of possible systematic deviations of temperatures measured according to the International Temperature Scale of 1990 (ITS-90), T90, and the thermodynamic temperatures T. The measurements in 1995 with the 676-nm-FR and the 800-nm-FR revealed a difference of 50 mK of T-T90 at temperatures around the freezing point of silver (961.78 °C). The observed difference decreases with decreasing temperatures, indicating that it may be attributed to a systematic deviation in the ITS-90 from T due to the gas thermometric temperature measurement at 457 °C, which has …}, language = {en} } @inproceedings{HartmannIshiiFukuzakietal., author = {Hartmann, J{\"u}rgen and Ishii, J. and Fukuzaki, T. and McEvoy, H.C. and Simpson, R. and Machin, Graham and Gutschwager, B. and Hollandt, J{\"o}rg}, title = {A comparison of the blackbody cavities for infrared ear thermometers of NMIJ, NPL, and PTB}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, address = {Zagrep}, pages = {1093 -- 1098}, language = {en} } @inproceedings{HartmannThomasMaetal., author = {Hartmann, J{\"u}rgen and Thomas, R. and Ma, C.K. and Steel, A. and Hill, K.}, title = {Bilateral comparison of the local realizations of the ITS-90 between the Silver point and 1700 °C using vacuum Tungsten-strip lamps as transfer standards between NRC and PTB}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, address = {Zagrep}, pages = {1069 -- 1073}, language = {en} } @inproceedings{HartmannHollandtAnhaltetal., author = {Hartmann, J{\"u}rgen and Hollandt, J{\"o}rg and Anhalt, Klaus and Sperfeld, P. and Sakharov, M. and Pikalev, Yu. and Ogarev, S. and Sapritsky, V.}, title = {Thermodynamic measurements for the melting curves of Re-C, TiC-C, and ZrC-C eutectics}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, address = {Zagrep}, pages = {189 -- 194}, language = {en} } @inproceedings{HartmannRothMoritzetal., author = {Hartmann, J{\"u}rgen and Roth, U. and Moritz, W. and Reichling, M.}, title = {Optimised strategies for thermal re-activation of LaF3/Pt-sensors based on photothermal characterisation}, series = {Photoacoustic and Photothermal Phenomena}, booktitle = {Photoacoustic and Photothermal Phenomena}, editor = {Scudieri, F. and Bertolotti, M.}, address = {Woodbury (New York)}, pages = {398 -- 400}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {Complete characterization of local thermal transfer in high quality CVD diamond}, series = {AIP Conference Proceedings (463)}, booktitle = {AIP Conference Proceedings (463)}, pages = {295 -- 299}, abstract = {Room temperature microscopic thermal transfer in a high quality chemical vapor deposited diamond sample is completely characterized with micrometer resolution. A thermoreflectance microscope measures thermal conductivity and its slight variations inside a grain. Measurements reveal an inhomogeneous conductivity distribution with highest values close to that of natural IIa diamond. Using the same microscope, frequency dependent investigations of thermal barriers located between diamond grains are performed. Thermal resistance is found to vary between 10-9 and 10-8 m2K/W. Frequency dependent measurements sensitive to three-dimensional heat flow and averaging over a variable number of grains yield an enormous decrease of thermal conductivity with decreasing modulation frequency. Taking the average of thermal conductivity inside the grains and an average value for the barrier height together …}, language = {en} } @inproceedings{HartmannBloembergenYamadaetal., author = {Hartmann, J{\"u}rgen and Bloembergen, P and Yamada, Y and Yamamoto, N}, title = {Realizing the High-Temperature Part of a Future ITS with the Aid of Eutectic Metal-Carbon Fixed Points}, series = {AIP Conference Proceedings (684)}, booktitle = {AIP Conference Proceedings (684)}, issn = {0-7354-0153-5}, pages = {291 -- 296}, abstract = {In the proposed scheme temperatures are defined by interpolation and extrapolation with respect to two reference fixed points (n=2), with assigned temperatures. The definition includes one full-range and two sub-ranges in temperature. The scheme in question will be compared with two alternatives referred to (1) as n=1, using one reference point only, as in the ITS-90, and (2) as n=0, involving direct measurement of the thermodynamic temperature by means of absolute radiometry.}, language = {en} } @inproceedings{HartmannMachinYamadaetal., author = {Hartmann, J{\"u}rgen and Machin, Graham and Yamada, Y. and Lowe, D. and Sasajima, N. and Anhalt, Klaus and Goebel, R. and McEvoy, H.C. and Bloembergen, P.}, title = {A comparison of high temperature fixed-points of Pt-C and Re-C constructed by BIPM, NMIJ and NPL}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, publisher = {LPM/FSB}, address = {Zagrep}, pages = {1049 -- 1056}, language = {en} } @inproceedings{HartmannAnhaltHollandtetal., author = {Hartmann, J{\"u}rgen and Anhalt, Klaus and Hollandt, J{\"o}rg and Machin, Graham and Lowe, D. and McEvoy, H. and Sakuma, F. and Ma, L.}, title = {Comparison of the high-temperature scales of the NMIJ and the NPL with the scale of the PTB in the temperature range from 1000 °C up to 2900 °C for measurements within the EU project HIMERT}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, address = {Zagrep}, pages = {1063 -- 1068}, language = {en} } @inproceedings{HartmannTegeler, author = {Hartmann, J{\"u}rgen and Tegeler, E.}, title = {Activities in the field of legal metrology and standardisation of clinical thermometers}, series = {Proceedings of Tempmeko 2004}, booktitle = {Proceedings of Tempmeko 2004}, editor = {Zvizdic, D.}, publisher = {LPM/FSB}, address = {Zagreb}, pages = {1191 -- 1196}, abstract = {Recently the CEN/TC 205/WG 12 Clinical Thermometer has finalised the European standard on clinical thermometers, EN 12470, by implementing the part 5 Clinical thermometers—Performance of infra-red ear thermometers (with maximum device). This last part of the EN 12470 series is dealing with the performance and requirements for infrared ear thermometers. The other four parts are dealing with metallic liquid-in-glass thermometers, phase change-type (dot matrix) thermometers, compact electrical thermometers (non-predictive and predictive), and electrical thermometers for continuous measurement. Beside this European standard there are national standards dealing with clinical thermometers, the most important in the USA and in Japan. In the field of legal metrology there are three OIML recommendations on clinical thermometers, covering the field of mercury-in-glass thermometers (R7), electrical thermometers for continuous measurements (R114), and electrical thermometers with maximum device (R 115).}, language = {en} } @inproceedings{HartmannMoritzRothetal., author = {Hartmann, J{\"u}rgen and Moritz, W. and Roth, U. and Heyde, M. and Rademann, K. and Reichling, M.}, title = {Nanosecond Range Heating and Temperature Measurement on Thin Layers}, series = {Proceedings of the International Conference on Modeling and Simulation of Microsystems, Semiconductors, Sensors and Actuators}, booktitle = {Proceedings of the International Conference on Modeling and Simulation of Microsystems, Semiconductors, Sensors and Actuators}, publisher = {MSM 99}, pages = {655 -- 658}, abstract = {A chemical semiconductor sensor for oxygen gas was activated by thermal treatment. The thin Pt layer of the n-Si/SiO2/Si3N4/LaF3/Pt field effect structure was used as the gate electrode for sensitivity measurements, heating resistance and temperature sensor. Taking advantage of using the gate electrode for heating only the sensitive two layer system LaF3/Pt (thickness only 300 nm) has to be at high temperature. The reactivation was shown to be a very fast process. Within a period of 10µs the structure was heated and the activation process was completed. The temperature measurement was done using the voltage drop at the gate and the current of the heating impulse. For the temperature measurement a resolution on the time scale of nanoseconds was achieved. The time dependent temperature distribution in the sensor multi layer structure was simulated using the CFD-ACE+ software of CFDRC. For the µs-impulses the temperature increase of only the thin layers and not the silicon bulk was shown.}, language = {en} } @inproceedings{HartmannFischer, author = {Hartmann, J{\"u}rgen and Fischer, Joachim}, title = {Radiator standards for accurate IR calibrations in remote sensing based on heatpipe blackbodies}, series = {Proceedings Volume 3821, Environmental Sensing and Applications}, booktitle = {Proceedings Volume 3821, Environmental Sensing and Applications}, number = {3821}, editor = {Carleer, M. and Hilton, M. and Lamp, T. and Reuter, R. and Russwurm, G.M. and Schaefer, K. and Weber, K. and Weitkamp, K. and Wolf, J. and Woppowa, L.}, publisher = {International Society for Optics and Photonics - Proceedings of SPIE}, pages = {395 -- 403}, abstract = {The demand of instrumentation in the field of remote sensing is increasing rapidly. For international compatibility, for reliable results and precise long-term investigation, necessary for example in the measurement of climatic trends, accurate traceability of the results to international standards or SI-units is mandatory. Additionally, interpretation of the results strongly requires a careful evaluation of the involved errors and the resulting uncertainties in order to allow for a rating of the obtained results. For that purpose quality assurance was introduced, not only for industrial fabrication, but also, and with increasing tendency, for industrial and scientific research. As an overview, the necessity and the possibilities of quality assurance in the area of remote sensing are discussed. Taking remote sensing of temperature as an example, the general approach is described. For that purpose, a description of heatpipe blackbodies …}, language = {en} } @inproceedings{HartmannFischer, author = {Hartmann, J{\"u}rgen and Fischer, Joachim}, title = {Calibration and investigation of infrared camera systems applying blackbody radiation}, series = {Thermosense XXIII}, booktitle = {Thermosense XXIII}, number = {4360}, editor = {Rozlonski, Andr{\´e}s E. and Dinwiddie, Ralph B.}, publisher = {International Society for Optics and Photonics - Proceedings of SPIE}, pages = {402 -- 411}, abstract = {An experimental facility is presented, which allows calibration and detailed investigation of infrared camera systems. Various blackbodies operating in the temperature range from -60 degree(s)C up to 3000 degree(s)C serve as standard radiation sources, enabling calibration of camera systems in a wide temperature and spectral range with highest accuracy. Quantitative results and precise long-term investigations, especially in detecting climatic trends, require accurate traceability to the International Temperature Scale of 1990 (ITS-90). For the used blackbodies the traceability to ITS- 90 is either realized by standard platinum resistance thermometers (in the temperature range below 962 degree(s)C) or by absolute and relative radiometry (in the temperature range above 962 degree(s)C). This traceability is fundamental for implementation of quality assurance systems and realization of different standardizations, for …}, language = {en} } @inproceedings{HartmannFriedrichSchilleretal., author = {Hartmann, J{\"u}rgen and Friedrich, R. and Schiller, S. and Fischer, J.}, title = {Non-isothermal temperature distribution and resulting emissivity corrections for the high temperature blackbody BB3200}, series = {Proc. 8th International Symposium on Temperature and Thermal Measurements in Industry and Science - Proceedings of Tempmeko 2001}, booktitle = {Proc. 8th International Symposium on Temperature and Thermal Measurements in Industry and Science - Proceedings of Tempmeko 2001}, editor = {Fellmuth, B. and Seidel, J. and Scholze, G.}, publisher = {VDI Verlag}, address = {Berlin}, pages = {227 -- 232}, language = {en} } @inproceedings{HartmannMcEvoyMachinetal., author = {Hartmann, J{\"u}rgen and McEvoy, H.C. and Machin, Graham and Friedrich, R. and Hollandt, J{\"o}rg}, title = {Comparison of the New NPL Primary Standard Ag Fixed-Point Blackbody Source with the Primary Standard Fixed Point of PTB}, series = {AIP Conference Proceedings (684)}, booktitle = {AIP Conference Proceedings (684)}, publisher = {American Institute of Physics}, isbn = {0-7354-0153-5}, pages = {909 -- 914}, abstract = {Above the freezing point of silver (961.78 °C), the International Temperature Scale of 1990 is defined in terms of Planck's radiation law. The scale is maintained and disseminated using a validated and linear pyrometer in conjunction with a blackbody reference source at either the Ag, Au (1064.18 °C) or Cu (1084.62 °C) freezing point. In order to realize the scale with the highest precision high quality, well-characterised, reproducible fixed-point blackbody sources are required. Such sources have been maintained at NPL for a number of years, but it was felt that improvements to the design would be beneficial. A new Ag point blackbody source has therefore been constructed. The new design will improve the quality and reproducibility of the melting and freezing plateaux and reduce errors due to the 'out-of-focus' size-of-source effect which is difficult to measure and to eliminate. Full details of the design of the new …}, language = {en} } @inproceedings{HartmannMachinBeynonetal., author = {Hartmann, J{\"u}rgen and Machin, G and Beynon, G and Edler, F and Fourrez, S and Lowe, D and Morice, R and Sadli, M and Villamanan, M}, title = {HIMERT}, series = {AIP Conference Proceedings}, booktitle = {AIP Conference Proceedings}, publisher = {American Institute of Physics}, isbn = {0-7354-0153-5}, pages = {285 -- 290}, abstract = {Metal-carbon eutectic mixtures show much promise for high-temperature standards applications. A research project, Novel, High temperature, Metal-carbon Eutectic fixed points for Radiation Thermometry, Radiometry and Thermocouples (HIMERT) was accepted by the European Union (submitted under the Framework 5 Growth Programme) with a view to developing a unified European approach to these standards. The objectives of the project are to develop fixed-point cells both for radiation thermometry/radiometry and contact thermometry calibration applications. In total three sets of cells will be developed, two for radiation thermometry (by BNM-INM and NPL) and one for contact sensors (by BNM-LNE) and comparisons performed of the differing crucible designs. The cells developed for radiation thermometry will be calibrated according to the ITS-90 and measured radiometrically by a third participant (PTB …}, language = {en} } @inproceedings{HartmannTaubertMonteetal., author = {Hartmann, J{\"u}rgen and Taubert, Dieter Richard and Monte, C. and Gutschwager, B. and Hollandt, J{\"o}rg}, title = {Traceable calibration of radiation sources from the visible to the far infrared for space borne applications at PTB}, series = {Proceedings of SPIE Volume 7474, Sensors, Systems, and Next-Generation Satellites XIII}, booktitle = {Proceedings of SPIE Volume 7474, Sensors, Systems, and Next-Generation Satellites XIII}, abstract = {The Physikalisch-Technische Bundesanstalt (PTB) has developed dedicated instrumentations and methods for the traceable calibration of space borne instruments in terms of the three fundamental radiometric units, i.e. spectral radiance (radiation temperature), spectral radiant intensity and spectral photon flux. The traceable calibration under conditions similar to the space environment is achieved by use of two major radiometric calibration facilities of PTB, the Spectral Radiance Comparator Facility (SRCF) and the Reduced Background Calibration Facility (RBCF) which are part of the Primary Temperature Radiator Facility of PTB and cover the wavelength range from the UV to the FIR (THz range). The improved detector instrumentations of the SRCF and RBCF, detailed calibration schemes and results of calibrations for space missions are presented.}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {Optimized strategies for thermal re-activation of LaF3/Pt-sensors based on photothermal characterization}, series = {AIP Conference Proceedings (463)}, booktitle = {AIP Conference Proceedings (463)}, publisher = {American Institute of Physics}, pages = {398 -- 400}, abstract = {Gas sensors based on a semiconductor-supported LaF3/Pt-structure require regular re-activation by thermal treatment. A convenient way to accomplish this is by applying an electrical current pulse to the Pt-electrode and controlling re-activation by the amount of Joule heat deposited. Pulse length has to be chosen to balance the requirements of thermal energy needed for re-activation and the constraints in peak thermal power to prevent damage. Prerequisite to optimization is a knowledge of the thermal response of the complicated thin film sensor system consisting of several layers with unknown thermal properties. Modulated photothermal microscopy was used to detect inhomogenities in thin film heating and early stages of failure under thermal load. It was found that the formation of gas bubbles in the film is one of the major sources of failure. These measurements were complemented by measurements of …}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {Thermodynamic temperature measurements of the melting curves of RE-C, TIC-C And ZRC-C eutectic irradiance mode fixed-point cells}, series = {Proceedings TEMPMEKO 2004}, booktitle = {Proceedings TEMPMEKO 2004}, pages = {189 -- 194}, abstract = {The thermodynamic temperatures of the phase transition of Re-C, TiC-C, and ZrC-C eutectic fixed-point cells have been measured for the first time using different filter radiometers in irradiance mode. The spectral responsivity of these filter radiometers was measured traceable to the primary detector standard of the PTB, a laser based cryogenic radiometer. The relative extended uncertainties of the spectral responsivities of the filter radiometers in the irradiance mode were in the range from 5· 10-4 up to 2.5· 10-3. The measurements have been performed at the high temperature calibration facilities of the VNIIOFI and the PTB with eutectic fixed-point cells manufactured by VNIIOFI.}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {Intercomparison of radiation temperature scales between PTB and NMIJ from 1000/spl deg/C to 2500/spl deg/C}, series = {Proceedings of the 41st SICE Annual Conference}, booktitle = {Proceedings of the 41st SICE Annual Conference}, publisher = {IEEE}, pages = {58 -- 62}, abstract = {The intercomparison of radiation temperature scales between PTB and NMIJ was carried out in September 2001. PTB sent their radiation thermometer LP3 to Japan and NMIJ made the comparison between the LP3 and NMIJs Topcon radiation thermometers with a comparison blackbody from 1000/spl deg/C to 2500/spl deg/C. Both scales agreed within /spl plusmn/0.8/spl deg/C in the whole range.}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {I3. 4-Radiometric calibration of the NIRSpec instrument on the James Webb Space Telescope in the wavelength range from 0.7 μm to 5.0 μm}, series = {SENSOR+TEST Conference 2009 - IRS² 2009 Proceedings}, booktitle = {SENSOR+TEST Conference 2009 - IRS² 2009 Proceedings}, pages = {249 -- 254}, language = {en} } @inproceedings{HartmannTaubertFischer, author = {Hartmann, J{\"u}rgen and Taubert, Dieter Richard and Fischer, Joachim}, title = {Characterization of the double-heatpipe blackbody LABB for use at temperatures below 500 C}, series = {Proceedings of TEMPMEKO (99)}, booktitle = {Proceedings of TEMPMEKO (99)}, editor = {Dubbeldam, J.F. and de Groot, M.J.}, publisher = {IMEKO}, address = {Delft}, pages = {511 -- 516}, abstract = {The large area double-heatpipe blackbody (LABB) used for comparing thermodynamic temperatures with the International Temperature Scale of 1990 (ITS-90) at temperatures higher than 600 C is based on two sodium heat pipes. The lowest temperature at which the sodium heat pipes work properly is strongly correlated to the onset of sodium evaporation. This is expected for temperatures well above 500 C. Planning to use the LABB for extending the comparison of thermodynamic temperatures with the ITS-90 to temperatures as low as possible, we measured the isothermal behaviour of the blackbody cavity starting at heatpipe temperatures of 400 C. The temperature of the cylindrical part of the cavity was measured with a standard platinum resistance thermometer (SPRT) sensing the bottom of the cavity and up to three quarter of the cylindrical part of the cavity. The obtained temperature profiles are well explained assuming the occurrence of two superimposing effects: a real nonisothermal behaviour of the LABB for temperatures below 500 C and a cooling of the SPRT caused by radiation loss through the aperture of the cavity. Applying a Monte-Carlo simulation we calculated the emissivity of the LABB at different heatpipe temperatures below 600 C using the obtained non-isothermal temperature distribution at the cylindrical walls. It was found that even at temperatures as low as 415 C the accuracy of the LABB is sufficient for comparison of thermodynamic temperatures and the ITS-90.}, language = {en} } @inproceedings{HartmannSadliMachinetal., author = {Hartmann, J{\"u}rgen and Sadli, M. and Machin, G. and Morice, R.}, title = {Realisation and comparison of metal-carbon eutectic points for radiation thermometry applications and W-Re thermocouple calibration}, series = {Proc. 8th Int. Symp. on Temperature and Thermal Measurements in Industry and Science - Proceedings of Tempmeko 2001}, booktitle = {Proc. 8th Int. Symp. on Temperature and Thermal Measurements in Industry and Science - Proceedings of Tempmeko 2001}, editor = {Fellmuth, B. and Seidel, J. and Scholze, G.}, publisher = {VDI Verlag}, address = {Berlin}, pages = {507 -- 512}, abstract = {For the sake of ensuring improved accuracy and traceability for temperature measurements above the copper point (1084 OC), four laboratories are joining their efforts in developing high-temperature fixed points based on eutectic transitions of metal-carbon mixtures [1]. These phase transitions, on the basis of radiation thermometry results presented thus far [2, 3], encouraged the participants to work towards two eventual applications: hightemperature fixed—point calibration sources for radiation thermometry, and fixed points for the calibration of contact thermometers, including Pt/Pd, Pt/Rh and W/Re thermocouples. Here will be given the up-to—date works accomplished within or in relation with this project in the participating laboratories. The perspectives of this work are wide and should allow the usage of such fixed points at temperatures ranging from 1150 C to 2700 C. The remaining uncertainty concerns the …}, language = {en} } @inproceedings{HartmannFischer, author = {Hartmann, J{\"u}rgen and Fischer, Joachim}, title = {Calibration of tungsten strip lamps as transfer standards for temperature}, series = {Proceedings of TEMPMEKO (99)}, booktitle = {Proceedings of TEMPMEKO (99)}, editor = {Dubbeldam, J.F. and de Groot, M.J.}, publisher = {IMEKO}, address = {Delft}, pages = {561 -- 566}, abstract = {An advanced method for the calibration of tungsten strip lamps is reviewed in detail. The method is based on measuring the ratio of the spectral radiances of two sources at different radiance temperatures TL by radiation thermometry. Instead of using the distribution temperature and the colour emissivity for the calculation of the radiance temperature, the derivative dTL/dλ in the vicinity of the effective wavelength of the detection system is applied. In a first step high-stability vacuum tungsten strip lamps are calibrated as first-order working standards with respect to fixed points of the International Temperature Scale of 1990 (ITS-90). In a subsequent step, secondary working standards are calibrated relative to these first order working standards with light of different wavelengths determined by interference filters. A detailed description of the evaluation procedure for the determination of the radiance temperature of the lamps is given and several problems encountered in operating the lamps are discussed. The standard uncertainties of the radiance temperature are below 0.2 K for the first order working standards.}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {Long term stability of the spectral responsivity of filter radiometers at the PTB}, series = {Proc. of TEMPMEKO}, booktitle = {Proc. of TEMPMEKO}, editor = {Zvizdic, D.}, pages = {977 -- 982}, abstract = {The Physikalisch-Technische Bundesanstalt (PTB) uses calibrated filter radiometers to measure the thermodynamic temperature of blackbodies applied for the realisation and dissemination of the spectral radiance and spectral irradiance. This paper presents the PTB experience with the stability of the spectral responsivities of two different sets of filter radiometers, a set of four broad-band filter radiometers with centroid wavelengths in the visible spectral range (437 nm, 510 nm, 558 nm and 728 nm), using a combination of coloured glass filters as wavelength selective elements and a set of five narrow-band interference filter radiometers with centroid wavelengths in the visible and in the near infrared wavelength range (676 nm, 802 nm, 903 nm and 1003 nm). The time period of their continuous investigation with respect to the relevant stability parameters, the integrated spectral responsivity and the centroid wavelength, is about seven years for the broad-band filter radiometers and up to ten years for the narrow-band interference filter radiometers. Both types of filter radiometers show sufficient stability for their application as high-accuracy temperature measurement instruments. Relative changes in the integrated spectral responsivity up to some parts in 103 and for the interference filter radiometers a linear increase of the centroid wavelength with time in the order of several ten picometers per year have been observed. A comparison between the two types of filter radiometers is given, with respect to the contribution of the stability of these parameters to the uncertainty budget of thermodynamic temperature determination. Reasons for the observed …}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {The PriTeRa facility of PTB for spectral radiance and irradiance calibrations and radiation thermometry in the range from {\`A}170 C up to 3200 C and from 200 nm up to 50 μm}, series = {Proc. Newrad}, booktitle = {Proc. Newrad}, pages = {13 -- 16}, abstract = {Blackbody radiators provide calculable spectral radiance and irradiance if their temperature and their emissivity is well known. Due to technical restrictions, one single blackbody can cover only a limited temperature range and therefore limited wavelengths for spectral radiance and irradiance calibrations. Space borne instruments for measuring the solar emission usually need calibrations from the UV to the near Infrared part of the optical spectrum [1] whereas remote sensing experiments for measuring earth surface temperatures for climate prediction or spaceborne instruments that deliver evidence for water on the surface of planet Mars [2] require calibration in the far infrared spectral range. To achieve these complementary requirements, PTB has set-up a series of blackbody based instrumentations, which are combined in the Primary Temperature Radiator facility (PriTeRa). To cover the whole wavelength range from 200 nm up to 800 µm different blackbody designs have to be applied.}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {A comparison of Co-C, Pd-C, Pt-C, Ru-C and Re-C eutectic fixed points independently manufactured by three different institutes}, series = {Proc. Newrad (Davos, Switzerland)}, booktitle = {Proc. Newrad (Davos, Switzerland)}, pages = {289 -- 290}, abstract = {In order to assess the performance and capability as well as the reproducibility of cell production five different Metal-carbon (MC) eutectic cells from three institutes were measured by radiation thermometry at PTB. The reproducibility of the melting temperature approached the requirements set by CCT/CCPR but significant differences were seen between different manufactures.}, language = {en} } @misc{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {Intercomparison of Radiation Temperature Scales}, series = {Proc. SICE 2002}, journal = {Proc. SICE 2002}, pages = {111 -- 115}, abstract = {The intercomparison of radiation temperature scales between PTB and NMIJ was carried out in September 2001. PTB sent their radiation thermometer LP3 to Japan and NMIJ made the comparison between the LP3 and NMIJ's Topcon radiation thermometers with a comparison blackbody from 1000 C to 2500 C. Both scales agreed within+ 0.8 C in the whole range.}, language = {en} } @inproceedings{HartmannRicolfiBatuelloetal., author = {Hartmann, J{\"u}rgen and Ricolfi, T. and Batuello, M. and Bosma, R. and van der Ham, E. and Fischer, J.}, title = {Comparison of local realizations of the ITS-90 between 920° C and 1590° C at 950 nm using vacuum tungsten strip lamps as transfer standards}, series = {Proc. of TEMPMEKO (2001)}, booktitle = {Proc. of TEMPMEKO (2001)}, editor = {Fellmuth, B. and Seidel, J. and Scholze, G.}, publisher = {VDI Verlag}, address = {Berlin}, pages = {839 -- 844}, language = {en} } @inproceedings{HartmannTaubert, author = {Hartmann, J{\"u}rgen and Taubert, Dieter Richard}, title = {Assessing blackbody emissivity by monte carlo simulation}, series = {Proc. of the Int. Conference of Infrared Sensors and Systems}, booktitle = {Proc. of the Int. Conference of Infrared Sensors and Systems}, publisher = {AMA Service GmbH}, pages = {133 -- 138}, language = {en} } @inproceedings{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {Measurement of T-T90 down to zinc point temperatures with absolute filter radiometry}, series = {Proc. of TEMPMEKO}, booktitle = {Proc. of TEMPMEKO}, pages = {377 -- 382}, 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}, title = {Development and validation of a long wavelength infrared (LWIR) radiation thermometer for contactless temperature measurements in gas turbines during operation}, series = {EVI-GTI and PIWG Joint Conference on Gas Turbine Instrumentation}, booktitle = {EVI-GTI and PIWG Joint Conference on Gas Turbine Instrumentation}, publisher = {IET}, pages = {1 -- 26}, abstract = {A collection of slides from the author's conference presentation is given. The presentation introduces the infrared-optical characterization of thermal barrier coatings and the development of LWIR pyrometer for measuring temperature in an operating gas turbine. The test facility for evaluating the LWIR pyrometer is also presented. This presentation includes the experimental setup for LWIR calibration and measurement.}, language = {en} } @inproceedings{HartmannSakumaMa, author = {Hartmann, J{\"u}rgen and Sakuma, F. and Ma, L.}, title = {Intercomparison of Radiation Temperature Scales between PTB and NMIJ from 1000-degree Celsius to 2500-degree Celsius}, series = {SICE Annual Conference Program and Abstracts SICE Annual Conference 2002}, booktitle = {SICE Annual Conference Program and Abstracts SICE Annual Conference 2002}, publisher = {The Society of Instrument and Control Engineers}, pages = {13 -- 13}, abstract = {The intercomparison of radiation temperature scales between PTB and NMIJ was carried out in September 2001. PTB sent their radiation thermometer LP3 to Japan and NMIJ made the comparison between the LP3 and NMIJ's Topcon radiation thermometers with a comparison blackbody from 1000 C to 2500 C. Both scales agreed within±0.8 C in the whole range.}, language = {en} } @inproceedings{BlotevogelEgermannGoldlueckeetal., author = {Blotevogel, Thomas and Egermann, Jan and Goldl{\"u}cke, J{\"u}rgen and Leipertz, Alfred and Hartmann, Matthias and Schenk, Martin and Berckm{\"u}ller, Martin}, title = {Untersuchungen zur Gemsichbildung in Wasserstoffmotoren}, editor = {Leipertz, Alfred}, publisher = {Esytec}, address = {Erlangen}, isbn = {3-931901-27-0}, pages = {12}, abstract = {Mittels der planaren laserinduzierten Fluoreszenz (PLIF) k{\"o}nnen im Brennraum eines Transparentmotors Messungen durchgef{\"u}hrt werden, die den Gemischbildungsprozess beim Wasserstoffmotor zweidimensional qualitativ darstellen. Auch quantitative Messungen und damit Aussagen {\"u}ber das Kraftstoff-Luft-Verh{\"a}ltnis im Brennraum sind m{\"o}glich. F{\"u}r diese Messungen wird ein Gasgemisch ans Helium und einer Tracersubstanz verwendet, und der Motor wird geschleppt. Bei Betrieb des Motors in der Teillast sind auch Messungen im gefeuerten Betrieb, d.h. mit Wasserstoff und zugesetzter Tracersubstanz, m{\"o}glich. Durch direkte Messung des Kraftstoff-Luft-Verh{\"a}ltnisses und der Wasserstoffkonzentration am befeuerten Aggregat mit Hilfe der Raman-Spektroskopie konnte nachgewiesen werden, daß mittels PLIF der Einstr{\"o}mvorgang qualitativ und das Kraftstoff-Luft-Verh{\"a}ltnis quantitativ grunds{\"a}tzlich richtig erfaßt werden. Qualitative und quantitative PLIF-Messungen sind prinzipiell nicht nur bei Wasserstoffmotoren, sondern auch bei Gasmotoren mit anderen Brenngasen denkbar. Allerdings sind noch weitere Arbeiten erforderlich, um den Quantifizierungsfehler deutlich abzusenken. Zuk{\"u}nftiges Verbesserungspotential f{\"u}r diese Meßtechnik besteht in verschiedenen Punkten. Dazu geh{\"o}rt die Optimierung und Anpassung der Mischstrecke zur Erzeugung des Gas-Luft-Gemisches mit definiertem Kraftstoff-Luft-Verh{\"a}ltnis an die jeweiligen Meßaufgaben, um den relativen Fehler des Lambda-Wertes noch weiter zu reduzieren. Eine Verringerung der Tracerkonzentration erscheint problemlos m{\"o}glich. Um das Problem der Hintergrundfluoreszenz zu l{\"o}sen, sind verschiedene M{\"o}glichkeiten denkbar, die noch genauer zu untersuchen sind.}, language = {de} } @incollection{BlotevogelGoldlueckeEgermannetal., author = {Blotevogel, Thomas and Goldl{\"u}cke, J{\"u}rgen and Egermann, Jan and Leipertz, Alfred and Hartmann, Matthias and Schenk, Martin and Berckm{\"u}ller, Martin}, title = {Gemischbildungsuntersuchung in Gasmotoren mittels optischer Messverfahren, speziell in Wasserstoffmotoren}, series = {Gasfahrzeuge}, booktitle = {Gasfahrzeuge}, editor = {Dingel, Oliver}, publisher = {expert verlag}, address = {Renningen}, isbn = {3816924395}, publisher = {Hochschule f{\"u}r Angewandte Wissenschaften W{\"u}rzburg-Schweinfurt}, pages = {205 -- 229}, abstract = {Planar laser-induced fluorescence (PLIF) has been successfully used for the investigation of the mixture formation process in hydrogen engines for passenger cars. Detailed information has been obtained about process development (qualitative measurement) and on fuel/air-ratio (quantitative measurement) inside the combustion chamber. These results can be used for further optimization of mixture formation and combustion process concerning emissions and fuel consumption. The measurement technique used is not only limited to hydrogen or to passenger car engines, but can also be applied to other fuel gases like natural gas or to other engine sizes like bus engines. The main topic of this paper is the experimental verification of the procedure which was executed by simultaneous PLIF and Raman scattering measurements. By Raman scattering the fuel/air-ratio can directly be determined from direct concentration measurements of the different gas species. The fuel/air-ratios determined by PLIF and Raman measurements are in good agreement indicating that a quantitative fuel/air-ratio measurement during the mixture formation process of gas and hydrogen engines is possible by PLIF. This fact is also confirmed by other measurements, e.g., global fuel/air-ratio calculated from measured intake air and fuel gas flow.}, language = {de} } @inproceedings{HartmannDobhanEngelmannetal., author = {Hartmann, J{\"u}rgen and Dobhan, Alexander and Engelmann, Bastian and Eberhardt, Lars and Heusinger, Moritz and Raab, C and Schleif, Frank-Michael and T{\"u}rk, M.}, title = {Optimierung von Prozessen und Werkzeugmaschinen durch Bereitstellung, Analyse und Soll-Ist-Vergleich von Produktionsdaten: Digitalkonferenz}, language = {en} } @inproceedings{HartmannHarrerDotterweichetal., author = {Hartmann, J{\"u}rgen and Harrer, S. and Dotterweich, C. and Zink, Markus H. and Hemberger, Frank and Ebert, Hans-Peter and Schnitzler, Tim}, title = {Phase change materials for use in thermally and electrically stressed insulation for high voltage applications}, series = {2016 IEEE Electrical Insulation Conference}, booktitle = {2016 IEEE Electrical Insulation Conference}, publisher = {IEEE}, isbn = {978-1-4673-8706-4}, pages = {605 -- 608}, abstract = {The temperature of high voltage equipment is often the limiting factor when transmitting electrical energy because the electrical insulation can get severely aged when the temperature is exceeding a certain limit. Hence, cooling has to be improved or heat generation must be reduced to avoid damage of the insulation. In this paper a new method was examined by investigating electrically insulating phase change materials which are able to store latent heat during a phase change from the solid to liquid state in times of high energy demand. To verify the electrically insulating properties of paraffins, one class of phase change materials, a special test cell was designed allowing the determination of breakdown voltage of phase change materials. The measurements on one paraffin sample proved the promising electrical insulating properties and it was shown that the breakdown voltage in the liquid state is comparable …}, 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{HarrerDotterweichHartmannetal., author = {Harrer, S. and Dotterweich, C. and Hartmann, J{\"u}rgen and Zink, M. and Schnitzler, Tim and Ebert, Hans-Peter and Hemberger, Frank}, title = {Paraffine als Phasenwechselmaterialen in der elektrischen Isolierung von Hochspannungsbauteilen}, language = {de} } @inproceedings{HartmannHarrerDotterweichetal., author = {Hartmann, J{\"u}rgen and Harrer, S. and Dotterweich, C. and Zink, Markus H.}, title = {On the conduction process of dielectric liquids based on mineral oil}, address = {Buenos Aires (Argentinien)}, 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} } @article{HartmannMachinBloembergenetal., author = {Hartmann, J{\"u}rgen and Machin, Graham and Bloembergen, P and Anhalt, Klaus and Sadli, M and Saunders, P and Wooliams, E and Yamada, Y and Yoon, H}, title = {Practical Implementation of the Mise en Pratique for the Definition of the Kelvin Above the Silver Point}, series = {International Journal of Thermophysics}, volume = {31}, journal = {International Journal of Thermophysics}, number = {8-9}, doi = {10.1007/s10765-010-0834-5}, pages = {1779 -- 1788}, abstract = {The "Mise en pratique for the definition of the kelvin" (MeP-K) was established in April 2006 to be the repository of information required to perform a "practical measurement of temperature in accordance with the International System of Units (SI)." This article describes the progress made by the MeP-K HT (High Temperature Task Group) of CCT-WG5 (radiation thermometry) in drawing together the appropriate methods for accessing thermodynamic temperature above the silver point involving direct radiometric measurements on the one hand and indirect extrapolation, interpolation, and least-squares fitting on the other. An examination of the uncertainties and a brief discussion of the advantages and disadvantages of the various approaches are given. A summary of the remaining issues to be resolved concludes the article.}, language = {en} } @article{HartmannKnoppShandyetal., author = {Hartmann, J{\"u}rgen and Knopp, Kevin and Shandy, Amir and Winterstein, Achim and Arduini, Mariacarla and Hemberger, Frank and Vidi, Stephan and Manara, Jochen and M{\"u}ller, Michael}, title = {Thermophysikalische Charakterisierung von W{\"a}rmed{\"a}mmschichten}, series = {tm - Technisches Messen}, volume = {88}, journal = {tm - Technisches Messen}, number = {12}, publisher = {Oldenbourg Wissenschaftsverlag}, doi = {10.1515/teme-2021-0074}, abstract = {Die Effizienzsteigerung moderner Gasturbinen erfordert die stetige Anhebung der Betriebstemperatur. Die derzeitigen Brenngastemperaturen liegen mit {\"u}ber 1400 °C signifikant {\"u}ber der kritischen Temperatur der verwendeten Turbinenst{\"a}hle. Zur Gew{\"a}hrleistung der Betriebssicherheit werden die Turbinenschaufeln neben Aktivk{\"u}hlung durch Beschichtung mit thermischen Schutzschichten, sogenannten thermal barrier coatings (TBC), gesch{\"u}tzt. Da es sich bei den TBC um Keramikschichten handelt, ist f{\"u}r die Erh{\"o}hung der Haftfestigkeit das Aufbringen eines Haftvermittlers (Verbindungsschicht) notwendig. Da die Eigenschaften d{\"u}nner Schichten stark von den Eigenschaften des Bulkmaterials abweichen k{\"o}nnen und zudem von der Herstellungsmethode beeinflusst werden, ist eine Untersuchung der thermischen und infrarot-optischen Eigenschaften der tats{\"a}chlichen Schichtstrukturen unumg{\"a}nglich, insbesondere im Hochtemperaturbereich. Hierf{\"u}r wurden Proben des reinen Tr{\"a}gerstahls, des Tr{\"a}gerstahls mit Haftvermittlerschicht und des kompletten Schichtsystems aus Tr{\"a}gerstahl, Haftvermittlerschicht und W{\"a}rmed{\"a}mmschicht verschiedener Dicken hergestellt und mittels Laser-Flash-Methode untersucht. Die Auswertung erfolgte dabei analytisch, ausgehend von der Tr{\"a}gerstahl-Einschichtprobe, {\"u}ber die Zweischicht- und Dreischichtsysteme. Vervollst{\"a}ndigt wurden diese Untersuchungen durch infrarot-optische Charakterisierungen, mit denen sich die W{\"a}rmeausbreitung durch die Schichtsysteme beschreiben l{\"a}sst. Zusammen mit den Laser-Flash Messungen erlaubt dies eine sp{\"a}tere Quantifizierung der einzelnen, bei Keramiken auftretenden, W{\"a}rmetransportmechanismen.}, 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} } @article{WehnertOchsSchmittetal., author = {Wehnert, Kira-Kristin and Ochs, Dennis and Schmitt, Jan and Hartmann, J{\"u}rgen and Schiffler, Andreas}, title = {Reducing Lifecycle Costs due to Profile Scanning of the Powder Bed in Metal Printing}, series = {Procedia CIRP 98}, volume = {98}, journal = {Procedia CIRP 98}, publisher = {Elsevir}, pages = {684 -- 689}, abstract = {First time right is one major goal in powder based 3D metal printing. Reaching this goal is driven by reducing life cycle costs for quality measures, to minimize scrap rate and to increase productivity under optimal resource efficiency. Therefore, monitoring the state of the powder bed for each printed layer is state of the art in selective laser melting. In the most modern approaches the quality monitoring is done by computer vision systems working with an interference on trained neural networks with images taken after exposure and after recoating. There are two drawbacks of this monitoring method: First, the sensor signals - the image of the powder bed - give no direct height information. Second, the application of this method needs to be trained and labeled with reference images for several cases. The novel approach presented in this paper uses a laser line scanner attached to the recoating machine. With this new concept, a direct threshold measure can be applied during the recoating process to detect deviations in height level without prior knowledge. The evaluation can be done online during recoating and feedback to the controller to monitor each individual layer. Hence, in case of deviations the location in the printing plane is an inherent measurement and will be used to decide which severity of error is reported. The signal is used to control the process, either by starting the recoating process again or stopping the printing process. With this approach, the sources of error for each layer can be evaluated with deep information to evaluate the cause of the error. This allows a reduction of failure in the future, which saves material costs, reduces running time of the machine life cycle phase in serial production and results in less rework for manufactured parts. Also a shorter throughput time per print job results, which means that the employee can spent more time to other print jobs and making efficient use of the employee's work force. In summary, this novel approach will not only reduce material costs but also operating costs and thus optimize the entire life cycle cost structure. The paper presents a first feasibility and application of the described approach for test workpieces in comparison to conventional monitoring systems on an EOS M290 machine.}, 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} } @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{HoefflinSauerSchiffleretal., author = {H{\"o}fflin, Dennis and Sauer, Christian and Schiffler, Andreas and Hartmann, J{\"u}rgen}, title = {Process Monitoring Using Synchronized Path Infrared Thermography in PBF-LB/M}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {16}, publisher = {MDPI}, doi = {10.3390/s22165943}, pages = {5943}, abstract = {Additive manufacturing processes, particularly Laser-Based Powder Bed Fusion of Metals (PBF-LB/M), enable the development of new application possibilities due to their manufacturing-specific freedom of design. These new fields of application require a high degree of component quality, especially in safety-relevant areas. This is currently ensured primarily via a considerable amount of downstream quality control. Suitable process monitoring systems promise to reduce this effort drastically. This paper introduces a novel monitoring method in order to gain process-specific thermal information during the manufacturing process. The Synchronized Path Infrared Thermography (SPIT) method is based on two synchronized galvanometer scanners allowing high-speed and high-resolution observations of the melt pool in the SWIR range. One scanner is used to steer the laser over the building platform, while the second scanner guides the field of view of an IR camera. With this setup, the melting process is observed at different laser powers, scan speeds and at different locations with respect to the laser position, in order to demonstrate the positioning accuracy of the system and to initially gain thermal process data of the melt pool and the heat-affected zone. Therefore, the SPIT system shows a speed independent overall accuracy of ±2 Pixel within the evaluated range. The system further allows detailed thermal observation of the melt pool and the surrounding heat-affected zone.}, language = {en} } @article{HoefflinHartmannRosiliusetal., author = {H{\"o}fflin, Dennis and Hartmann, J{\"u}rgen and Rosilius, Maximilian and Seitz, Philipp and Schiffler, Andreas}, title = {Opto-Thermal Investigation of Additively Manufactured Steel Samples as a Function of the Hatch Distance}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {1}, publisher = {MDPI}, issn = {1424-8220}, doi = {10.3390/s22010046}, pages = {46}, abstract = {Nowadays, additive manufacturing processes are becoming more and more appealing due to their production-oriented design guidelines, especially with regard to topology optimisation and minimal downstream production depth in contrast to conventional technologies. However, a scientific path in the areas of quality assurance, material and microstructural properties, intrinsic thermal permeability and dependent stress parameters inhibits enthusiasm for the potential degrees of freedom of the direct metal laser melting process (DMLS). Especially in quality assurance, post-processing destructive measuring methods are still predominantly necessary in order to evaluate the components adequately. The overall objective of these investigations is to gain process knowledge make reliable in situ statements about component quality and material properties based on the process parameters used and emission values measured. The knowledge will then be used to develop non-destructive tools for the quality management of additively manufactured components. To assess the effectiveness of the research design in relation to the objectives for further investigations, this pre-study evaluates the dependencies between the process parameters, process emission during manufacturing and resulting thermal diffusivity and the relative density of samples fabricated by DMLS. Therefore, the approach deals with additively built metal samples made on an EOS M290 apparatus with varying hatch distances while simultaneously detecting the process emission. Afterwards, the relative density of the samples is determined optically, and thermal diffusivity is measured using the laser flash method. As a result of this pre-study, all interactions of the within factors are presented. The process variable hatch distance indicates a strong influence on the resulting material properties, as an increase in the hatch distance from 0.11 mm to 1 mm leads to a drop in relative density of 57.4\%. The associated thermal diffusivity also reveals a sharp decrease from 5.3 mm2/s to 1.3 mm2/s with growing hatch distances. The variability of the material properties can also be observed in the measured process emissions. However, as various factors overlap in the thermal radiation signal, no clear assignment is possible within the scope of this work.}, 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{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{HoefflinSauerSchiffleretal., author = {H{\"o}fflin, Dennis and Sauer, Christian and Schiffler, Andreas and Manara, Jochen and Hartmann, J{\"u}rgen}, title = {Pixelwise high-temperature calibration for in-situ temperature measuring in powder bed fusion of metal with laser beam}, series = {Heliyon}, volume = {10}, journal = {Heliyon}, number = {7}, publisher = {Elsevier BV}, issn = {2405-8440}, doi = {10.1016/j.heliyon.2024.e28989}, abstract = {High-temperature calibration methods in additive manufacturing involve the use of advanced techniques to accurately measure and control the temperature of the build material during the additive manufacturing process. Infrared cameras, blackbody radiation sources and non-linear optimization algorithms are used to correlate the temperature of the material with its emitted thermal radiation. This is essential for ensuring the quality and repeatability of the final product. This paper presents the calibration procedure of an imaging system for in-situ measurement of absolute temperatures and temperature gradients during powder bed fusion of metal with laser beam (PBF-LB/M) in the temperature range of 500 K-1500 K. It describes the design of the optical setup to meet specific requirements in this application area as well as the procedure for accounting the various factors influencing the temperature measurement. These include camera-specific effects such as varying spectral sensitivities of the individual pixels of the sensor as well as influences of the exposure time and the exposed sensor area. Furthermore, influences caused by the complex optical path, such as inhomogeneous transmission properties of the galvanometer scanner as well as angle-dependent transmission properties of the f-theta lens were considered. A two-step fitting algorithm based on Planck's law of radiation was applied to best represent the correlation. With the presented procedure the calibrated thermography system provides the ability to measure absolute temperatures under real process conditions with high accuracy.}, language = {en} }