Seeger, Thomas
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Publication Access status: Open Access , ATHENA Research BookThe ATHENA European University is an alliance of nine Higher Education Institutions with the mission of fostering excellence in research and innovation by facilitating international cooperation. The ATHENA acronym stands for Advanced Technologies in Higher Education Alliance. The partner institutions are from France, Germany, Greece, Italy, Lithuania, Portugal, and Slovenia: the University of Orléans, the University of Siegen, the Hellenic Mediterranean University, the Niccolò Cusano University, the Vilnius Gediminas Technical University, the Polytechnic Institute of Porto, and the University of Maribor. In 2022 institutions from Poland and Spain joined the alliance: the Maria Curie-Skłodowska University and the University of Vigo. This research book presents a selection of the ATHENA university partners' research activities. It incorporates peer-reviewed original articles, reprints and student contributions. The ATHENA Research Book provides a platform that promotes joint and interdisciplinary research projects of both advanced and early-career researchers.Source Type:Book1 404 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Experimental Determination of the Temperature‐Dependent Broadening Effect of Water Vapour on the S‐Branch Raman Linewidths of Nitrogen(2024); ; ABSTRACT This work reports the S‐branch Raman linewidths of N 2 broadened by H 2 O vapour at temperatures 870–1900 K determined using the picosecond time‐resolved pure rotational coherent anti‐Stokes Raman scattering (RCARS) approach. The coherent dephasing time constant of nitrogen in a binary mixture was determined from the time trace fitting of the RCARS signal. Raman linewidths of N 2 for four different binary mixture compositions up to 20% H 2 O were obtained for each temperature and the N 2 ‐H 2 O broadening coefficient was determined. The decay of nitrogen broadened by water vapour is faster than that of self‐broadened nitrogen for all temperatures leading to a higher Raman linewidth. Respectively, the S‐branch Raman linewidths of N 2 ‐H 2 O deviate significantly in magnitude and slope from the Q‐branch Raman linewidth calculated by the modified energy gap (MEG) law. Therefore, taking into account the broadening effect of water molecules in nitrogen has the potential to significantly improve thermometry and species concentration determination. The determined S‐branch Raman linewidths and broadening coefficient will therefore find application in combustion and reactive flow diagnostics.Source Type:ArticleDOI:10.1002/JRS.67424 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Two-color four-wave mixing contribution to an electrostrictive laser-induced grating signal in CO<sub>2</sub>–N<sub>2</sub> mixtures and gas diagnostics(2023); ; Multiparameter determination in the gas phase using the versatile laser-induced grating (LIG) technique is a challenging task due to interdependence of observables on multiple thermodynamic parameters. In CO 2 -N 2 mixtures, simultaneous determination of species concentration and gas temperature can be achieved by using an additional CO 2 concentration-dependent contribution to the LIG signal, which appears if 1064 nm pump pulses are employed. This contribution can be attributed to a direct, quasi-resonant two-color four-wave mixing (TCFWM) of the pump and probe radiations in CO 2 . A detailed study of the laser power and beam polarization, as well as mixture composition, pressure, and temperature dependencies of the TCFWM intensity relative to that of the LIG signal, allowed for the formulation of analytical relations enabling simultaneous mixture composition and temperature determination.Source Type:Article3