@misc{BrinkmannKoellnerMerketal.2023, author = {Brinkmann, Pia and K{\"o}llner, Nicole and Merk, Sven and Beitz, Toralf and Altenberger, Uwe and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Comparison of handheld and echelle spectrometer to assess copper in ores by means of laser-induced breakdown spectroscopy (LIBS)}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1311}, issn = {1866-8372}, doi = {10.25932/publishup-58474}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-584742}, pages = {19}, year = {2023}, abstract = {Its properties make copper one of the world's most important functional metals. Numerous megatrends are increasing the demand for copper. This requires the prospection and exploration of new deposits, as well as the monitoring of copper quality in the various production steps. A promising technique to perform these tasks is Laser Induced Breakdown Spectroscopy (LIBS). Its unique feature, among others, is the ability to measure on site without sample collection and preparation. In this work, copper-bearing minerals from two different deposits are studied. The first set of field samples come from a volcanogenic massive sulfide (VMS) deposit, the second part from a stratiform sedimentary copper (SSC) deposit. Different approaches are used to analyze the data. First, univariate regression (UVR) is used. However, due to the strong influence of matrix effects, this is not suitable for the quantitative analysis of copper grades. Second, the multivariate method of partial least squares regression (PLSR) is used, which is more suitable for quantification. In addition, the effects of the surrounding matrices on the LIBS data are characterized by principal component analysis (PCA), alternative regression methods to PLSR are tested and the PLSR calibration is validated using field samples.}, language = {en} } @article{SchirmackBoehmBraueretal.2014, author = {Schirmack, Janosch and Boehm, Michael and Brauer, Chris and L{\"o}hmannsr{\"o}ben, Hans-Gerd and de Vera, Jean-Pierre Paul and Moehlmann, Diedrich and Wagner, Dirk}, title = {Laser spectroscopic real time measurements of methanogenic activity under simulated Martian subsurface analog conditions}, series = {Planetary and space science}, volume = {98}, journal = {Planetary and space science}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-0633}, doi = {10.1016/j.pss.2013.08.019}, pages = {198 -- 204}, year = {2014}, abstract = {On Earth, chemolithoautothrophic and anaerobic microorganisms such as methanogenic archaea are regarded as model organisms for possible subsurface life on Mars. For this reason, the methanogenic strain Methanosarcina soligelidi (formerly called Methanosarcina spec. SMA-21), isolated from permafrost-affected soil in northeast Siberia, has been tested under Martian thermo-physical conditions. In previous studies under simulated Martian conditions, high survival rates of these microorganisms were observed. In our study we present a method to measure methane production as a first attempt to study metabolic activity of methanogenic archaea during simulated conditions approaching conditions of Mars-like environments. To determine methanogenic activity, a measurement technique which is capable to measure the produced methane concentration with high precision and with high temporal resolution is needed. Although there are several methods to detect methane, only a few fulfill all the needed requirements to work within simulated extraterrestrial environments. We have chosen laser spectroscopy, which is a non-destructive technique that measures the methane concentration without sample taking and also can be run continuously. In our simulation, we detected methane production at temperatures down to -5 degrees C, which would be found on Mars either temporarily in the shallow subsurface or continually in the deep subsurface. The pressure of 50 kPa which we used in our experiments, corresponds to the expected pressure in the Martian near subsurface. Our new device proved to be fully functional and the results indicate that the possible existence of methanogenic archaea in Martian subsurface habitats cannot be ruled out. (C) 2013 Published by Elsevier Ltd.}, language = {en} } @incollection{LueckBalderjahnKammetal.2000, author = {L{\"u}ck, Erika and Balderjahn, Ingo and Kamm, Birgit and Greil, Holle and Wallschl{\"a}ger, Hans-Dieter and Jessel, Beate and B{\"o}ckmann, Christine and Oberh{\"a}nsli, Roland and Soyez, Konrad and Schmeer, Ernst and Blumenstein, Oswald and Berndt, Klaus-Peter and Edeling, Thomas and Friedrich, Sabine and Kaden, Klaus and Scheller, Frieder W. and Petersen, Hans-Georg and Asche, Hartmut and Bronstert, Axel and Giest, Hartmut and Gaedke, Ursula and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Jeltsch, Florian and J{\"a}nkel, Ralph and Gzik, Axel and Bork, Hans-Rudolf and Bork, Hans-Rudolf}, title = {Umweltforschung f{\"u}r das Land Brandenburg : Arbeitsgruppen und Professuren}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-3797}, publisher = {Universit{\"a}t Potsdam}, year = {2000}, language = {de} }