TY - JOUR
A1 - Carvalho, Thayslan
A1 - Brosinsky, Arlena
A1 - Foerster, Saskia
A1 - Teixeira, Adunias
A1 - Medeiros, Pedro Henrique Augusto
T1 - Reservoir sediment characterisation by diffuse reflectance spectroscopy in a semiarid region to support sediment reuse for soil fertilization
JF - Journal of soils and sediments : protection, risk assessment and remediation
N2 - Purpose:
Soil erosion by water yields sediment to surface reservoirs, reducing their storage capacities, changing their geometry, and degrading water quality. Sediment reuse, i.e., fertilization of agricultural soils with the nutrient-enriched sediment from reservoirs, has been proposed as a recovery strategy. However, the sediment needs to meet certain criteria. In this study, we characterize sediments from the densely dammed semiarid Northeast Brazil by VNIR-SWIR spectroscopy and assess the effect of spectral resolution and spatial scale on the accuracy of N, P, K, C, electrical conductivity, and clay prediction models.
Methods
Sediment was collected in 10 empty reservoirs, and physical and chemical laboratory analyses as well as spectral measurements were performed. The spectra, initially measured at 1 nm spectral resolution, were resampled to 5 and 10 nm, and samples were analysed for both high and low spectral resolution at three spatial scales, namely (1) reservoir, (2) catchment, and (3) regional scale.
Results
Partial least square regressions performed from good to very good in the prediction of clay and electrical conductivity from reservoir (<40 km(2)) to regional (82,500 km(2)) scales. Models for C and N performed satisfactorily at the reservoir scale, but degraded to unsatisfactory at the other scales. Models for P and K were more unstable and performed from unsatisfactorily to satisfactorily at all scales. Coarsening spectral resolution by up to 10 nm only slightly degrades the models' performance, indicating the potential of characterizing sediment from spectral data captured at lower resolutions, such as by hyperspectral satellite sensors.
Conclusion:
By reducing the costly and time-consuming laboratory analyses, the method helps to promote the sediment reuse as a practice of soil and water conservation.
KW - Sediment characterization
KW - Spectroscopy
KW - Sediment reuse
KW - Surface
KW - reservoirs
KW - Semiarid
KW - Brazil
Y1 - 2022
U6 - https://doi.org/10.1007/s11368-022-03281-1
SN - 1439-0108
SN - 1614-7480
VL - 22
SP - 2557
EP - 2577
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Picconi, David
T1 - Nonadiabatic quantum dynamics of the coherent excited state intramolecular proton transfer of 10-hydroxybenzo[h]quinoline
JF - Photochemical & photobiological sciences
N2 - The photoinduced nonadiabatic dynamics of the enol-keto isomerization of 10-hydroxybenzo[h]quinoline (HBQ) are studied computationally using high-dimensional quantum dynamics. The simulations are based on a diabatic vibronic coupling Hamiltonian, which includes the two lowest pi pi* excited states and a n pi* state, which has high energy in the Franck-Condon zone, but significantly stabilizes upon excited state intramolecular proton transfer. A procedure, applicable to large classes of excited state proton transfer reactions, is presented to parametrize this model using potential energies, forces and force constants, which, in this case, are obtained by time-dependent density functional theory. The wave packet calculations predict a time scale of 10-15 fs for the photoreaction, and reproduce the time constants and the coherent oscillations observed in time- resolved spectroscopic studies performed on HBQ. In contrast to the interpretation given to the most recent experiments, it is found that the reaction initiated by 1 pi pi* <- S-0 photoexcitation proceeds essentially on a single potential energy surface, and the observed coherences bear signatures of Duschinsky mode-mixing along the reaction path. The dynamics after the 2 pi pi* <- S-0 excitation are instead nonadiabatic, and the n pi* state plays a major role in the relaxation process. The simulations suggest a mainly active role of the proton in the isomerization, rather than a passive migration assisted by the vibrations of the benzoquinoline backbone.
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KW - Excited state proton transfer
KW - Quantum dynamics
KW - Nonadiabatic effects
KW - Spectroscopy
KW - Coherences
Y1 - 2021
U6 - https://doi.org/10.1007/s43630-021-00112-z
SN - 1474-905X
SN - 1474-9092
VL - 20
IS - 11
SP - 1455
EP - 1473
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Rousseau, Batiste
A1 - Erard, Stéphane
A1 - Beck, P.
A1 - Quirico, Eric
A1 - Schmitt, B.
A1 - Brissaud, O.
A1 - Montes-Hernandez, G.
A1 - Capaccioni, F.
A1 - Filacchione, Gianrico
A1 - Bockelee-Morvan, Dominique
A1 - Leyrat, C.
A1 - Ciarniello, M.
A1 - Raponi, Andrea
A1 - Kappel, David
A1 - Arnold, G.
A1 - Moroz, L. V.
A1 - Palomba, Ernesto
A1 - Tosi, Federico
T1 - Laboratory simulations of the Vis-NIR spectra of comet 67P using sub-mu m sized cosmochemical analogues
JF - Icarus : international journal of solar system studies
N2 - Laboratory spectral measurements of relevant analogue materials were performed in the framework of the Rosetta mission in order to explain the surface spectral properties of comet 67P. Fine powders of coal, iron sulphides, silicates and their mixtures were prepared and their spectra measured in the Vis-IR range. These spectra are compared to a reference spectrum of 67P nucleus obtained with the VIRTIS/Rosetta instrument up to 2.7 mu m, excluding the organics band centred at 3.2 mu m. The species used are known to be chemical analogues for cometary materials which could be present at the surface of 67P. Grain sizes of the powders range from tens of nanometres to hundreds of micrometres. Some of the mixtures studied here actually reach the very low reflectance level observed by VIRTIS on 67P. The best match is provided by a mixture of sub-micron coal, pyrrhotite, and silicates. Grain sizes are in agreement with the sizes of the dust particles detected by the GIADA, MIDAS and COSIMA instruments on board Rosetta. The coal used in the experiment is responsible for the spectral slope in the visible and infrared ranges. Pyrrhotite, which is strongly absorbing, is responsible for the low albedo observed in the NIR. The darkest components dominate the spectra, especially within intimate mixtures. Depending on sample preparation, pyrrhotite can coat the coal and silicate aggregates. Such coating effects can affect the spectra as much as particle size. In contrast, silicates seem to play a minor role. (c) 2017 Elsevier Inc. All rights reserved.
KW - Comets
KW - Comets nucleus
KW - Comets composition
KW - Spectroscopy
KW - Experimental techniques
Y1 - 2018
U6 - https://doi.org/10.1016/j.icarus.2017.10.015
SN - 0019-1035
SN - 1090-2643
VL - 306
SP - 306
EP - 318
PB - Elsevier
CY - San Diego
ER -
TY - JOUR
A1 - Zehbe, Rolf
A1 - Zehbe, Kerstin
T1 - Strontium doped poly-epsilon-caprolactone composite scaffolds made by reactive foaming
JF - The European journal of the history of economic thought
N2 - In the reconstruction and regeneration of bone tissue, a primary goal is to initiate bone growth and to stabilize the surrounding bone. In this regard, a potentially useful component in biomaterials for bone tissue engineering is strontium, which acts as cationic active agent, triggering certain intracellular pathways and acting as so called dual action bone agent which inhibits bone resorption while stimulating bone regeneration. In this study we established a novel processing for the foaming of a polymer (poly-epsilon-caprolactone) and simultaneous chemical reaction of a mixture of calcium and strontium hydroxides to the respective carbonates using supercritical carbon dioxide. The resultant porous composite scaffold was optimized in composition and strontium content and was characterized via different spectroscopic (infrared and Raman spectroscopy, energy dispersive X-ray spectroscopy), imaging (SEM, mu CT), mechanical testing and in vitro methods (fluorescence vital staining, MTT-assay). As a result, the composite scaffold showed good in vitro biocompatibility with partly open pore structure and the expected chemistry. First mechanical testing results indicate sufficient mechanical stability to support future in vivo applications. (C) 2016 Elsevier B.V. All rights reserved.
KW - Strontium
KW - Poly-epsilon-caprolactone
KW - Porous scaffold
KW - CAL-72 osteoblasts
KW - L-929 fibroblasts
KW - Reactive foaming
KW - mu CT imaging
KW - Spectroscopy
Y1 - 2016
U6 - https://doi.org/10.1016/j.msec.2016.05.045
SN - 0928-4931
SN - 1873-0191
VL - 67
SP - 259
EP - 266
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Brosinsky, Arlena
A1 - Förster, Saskia
A1 - Segl, Karl
A1 - Lopez-Tarazon, José Andrés
A1 - Pique, Gemma
A1 - Bronstert, Axel
T1 - Spectral fingerprinting: characterizing suspended sediment sources by the use of VNIR-SWIR spectral information
JF - Journal of soils and sediments : protection, risk assessment and remediation
N2 - Knowledge of sediment sources is a prerequisite for sustainable management practices and may furthermore improve our understanding of water and sediment fluxes. Investigations have shown that a number of characteristic soil properties can be used as "fingerprints" to trace back the sources of river sediments. Spectral properties have recently been successfully used as such characteristics in fingerprinting studies. Despite being less labour-intensive than geochemical analyses, for example, spectroscopy allows measurements of small amounts of sediment material (> 60 mg), thus enabling inexpensive analyses even of intra-event variability. The focus of this study is on the examination of spectral properties of fluvial sediment samples to detect changes in source contributions, both between and within individual flood events.
Sediment samples from the following three different origins were collected in the Isabena catchment (445 km(2)) in the central Spanish Pyrenees: (1) soil samples from the main potential source areas, (2) stored fine sediment from the channel bed once each season in 2011 and (3) suspended sediment samples during four flood events in autumn 2011 and spring 2012 at the catchment outlet as well as at several subcatchment outlets. All samples were dried and measured for spectral properties in the laboratory using an ASD spectroradiometer. Colour parameters and physically based features (e.g. organic carbon, iron oxide and clay content) were calculated from the spectra. Principal component analyses (PCA) were applied to all three types of samples to determine natural clustering of samples, and a mixing model was applied to determine source contributions.
We found that fine sediment stored in the river bed seems to be mainly influenced by grain size and seasonal variability, while sampling location-and thus the effect of individual tributaries or subcatchments-seem to be of minor importance. Suspended sediment sources were found to vary between, as well as within, flood events; although badlands were always the major source. Forests and grasslands contributed little (< 10 %), and other sources (not further determinable) contributed up to 40 %. The analyses further suggested that sediment sources differ among the subcatchments and that subcatchments comprising relatively large proportions of badlands contributed most to the four flood events analyzed.
Spectral fingerprints provide a rapid and cost-efficient alternative to conventional fingerprint properties. However, a combination of spectral and conventional fingerprint properties could potentially permit discrimination of a larger number of source types.
KW - Isabena river
KW - Mixing models
KW - Northeast Spain
KW - Sediment fingerprinting
KW - Spectroscopy
KW - Suspended sediment
Y1 - 2014
U6 - https://doi.org/10.1007/s11368-014-0927-z
SN - 1439-0108
SN - 1614-7480
VL - 14
IS - 12
SP - 1965
EP - 1981
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Brosinsky, Arlena
A1 - Förster, Saskia
A1 - Segl, Karl
A1 - Kaufmann, Hermann
T1 - Spectral fingerprinting: sediment source discrimination and contribution modelling of artificial mixtures based on VNIR-SWIR spectral properties
JF - Journal of soils and sediments : protection, risk assessment and remediation
N2 - Knowledge of the origin of suspended sediment is important for improving our understanding of sediment dynamics and thereupon support of sustainable watershed management. An direct approach to trace the origin of sediments is the fingerprinting technique. It is based on the assumption that potential sediment sources can be discriminated and that the contribution of these sources to the sediment can be determined on the basis of distinctive characteristics (fingerprints). Recent studies indicate that visible-near-infrared (VNIR) and shortwave-infrared (SWIR) reflectance characteristics of soil may be a rapid, inexpensive alternative to traditional fingerprint properties (e.g. geochemistry or mineral magnetism).
To further explore the applicability of VNIR-SWIR spectral data for sediment tracing purposes, source samples were collected in the Isabena watershed, a 445 km(2) dryland catchment in the central Spanish Pyrenees. Grab samples of the upper soil layer were collected from the main potential sediment source types along with in situ reflectance spectra. Samples were dried and sieved, and artificial mixtures of known proportions were produced for algorithm validation. Then, spectral readings of potential source and artificial mixture samples were taken in the laboratory. Colour coefficients and physically based parameters were calculated from in situ and laboratory-measured spectra. All parameters passing a number of prerequisite tests were subsequently applied in discriminant function analysis for source discrimination and mixing model analyses for source contribution assessment.
The three source types (i.e. badlands, forest/grassland and an aggregation of other sources, including agricultural land, shrubland, unpaved roads and open slopes) could be reliably identified based on spectral parameters. Laboratory-measured spectral fingerprints permitted the quantification of source contribution to artificial mixtures, and introduction of source heterogeneity into the mixing model decreased accuracies for some source types. Aggregation of source types that could not be discriminated did not improve mixing model results. Despite providing similar discrimination accuracies as laboratory source parameters, in situ derived source information was found to be insufficient for contribution modelling.
The laboratory mixture experiment provides valuable insights into the capabilities and limitations of spectral fingerprint properties. From this study, we conclude that combinations of spectral properties can be used for mixing model analyses of a restricted number of source groups, whereas more straightforward in situ measured source parameters do not seem suitable. However, modelling results based on laboratory parameters also need to be interpreted with care and should not rely on the estimates of mean values only but should consider uncertainty intervals as well.
KW - Artificial mixture
KW - Mixing model
KW - Sediment fingerprinting
KW - Spectroscopy
Y1 - 2014
U6 - https://doi.org/10.1007/s11368-014-0925-1
SN - 1439-0108
SN - 1614-7480
VL - 14
IS - 12
SP - 1949
EP - 1964
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Zude, Manuela
A1 - Pflanz, Michael
A1 - Spinelli, Lorenzo
A1 - Dosche, Carsten
A1 - Torricelli, Alessandro
T1 - Non-destructive analysis of anthocyanins in cherries by means of Lambert-Beer and multivariate regression based on spectroscopy and scatter correction using time-resolved analysis
JF - Journal of food engineering
N2 - In high-value sweet cherry (Prunus avium), the red coloration - determined by the anthocyanins content - is correlated with the fruit ripeness stage and market value. Non-destructive spectroscopy has been introduced in practice and may be utilized as a tool to assess the fruit pigments in the supply chain processes. From the fruit spectrum in the visible (Vis) wavelength range, the pigment contents are analyzed separately at their specific absorbance wavelengths.
A drawback of the method is the need for re-calibration due to varying optical properties of the fruit tissue. In order to correct for the scattering differences, most often the spectral intensity in the visible spectrum is normalized by wavelengths in the near infrared (NIR) range, or pre-processing methods are applied in multivariate calibrations.
In the present study, the influence of the fruit scattering properties on the Vis/NIR fruit spectrum were corrected by the effective pathlength in the fruit tissue obtained from time-resolved readings of the distribution of time-of-flight (DTOF). Pigment analysis was carried out according to Lambert-Beer law, considering fruit spectral intensities, effective pathlength, and refractive index. Results were compared to commonly applied linear color and multivariate partial least squares (PLS) regression analysis. The approaches were validated on fruits at different ripeness stages, providing variation in the scattering coefficient and refractive index exceeding the calibration sample set.
In the validation, the measuring uncertainty of non-destructively analyzing fruits with Vis/NIR spectra by means of PLS or Lambert-Beer in comparison with combined application of Vis/NIR spectroscopy and DTOF measurements showed a dramatic bias reduction as well as enhanced coefficients of determination when using both, the spectral intensities and apparent information on the scattering influence by means of DTOF readings. Corrections for the refractive index did not render improved results.
KW - Cherry
KW - DTOF
KW - Effective pathlength
KW - Fruit maturity
KW - Lambert-Beer
KW - NIR
KW - Non-invasive
KW - Pigments
KW - PLS
KW - Ripeness
KW - Sensor fusion
KW - Spectroscopy
KW - Time-resolved spectroscopy
KW - TIRF
KW - Vis
KW - Scattering
Y1 - 2011
U6 - https://doi.org/10.1016/j.jfoodeng.2010.09.021
SN - 0260-8774
VL - 103
IS - 1
SP - 68
EP - 75
PB - Elsevier
CY - Oxford
ER -
TY - JOUR
A1 - de Vera, Jean-Pierre Paul
A1 - Böttger, Ute
A1 - de la Torre Nötzel, Rosa
A1 - Sanchez, Francisco J.
A1 - Grunow, Dana
A1 - Schmitz, Nicole
A1 - Lange, Caroline
A1 - Hübers, Heinz-Wilhelm
A1 - Billi, Daniela
A1 - Baque, Mickael
A1 - Rettberg, Petra
A1 - Rabbow, Elke
A1 - Reitz, Günther
A1 - Berger, Thomas
A1 - Möller, Ralf
A1 - Bohmeier, Maria
A1 - Horneck, Gerda
A1 - Westall, Frances
A1 - Jänchen, Jochen
A1 - Fritz, Jörg
A1 - Meyer, Cornelia
A1 - Onofri, Silvano
A1 - Selbmann, Laura
A1 - Zucconi, Laura
A1 - Kozyrovska, Natalia
A1 - Leya, Thomas
A1 - Foing, Bernard
A1 - Demets, Rene
A1 - Cockell, Charles S.
A1 - Bryce, Casey
A1 - Wagner, Dirk
A1 - Serrano, Paloma
A1 - Edwards, Howell G. M.
A1 - Joshi, Jasmin Radha
A1 - Huwe, Björn
A1 - Ehrenfreund, Pascale
A1 - Elsaesser, Andreas
A1 - Ott, Sieglinde
A1 - Meessen, Joachim
A1 - Feyh, Nina
A1 - Szewzyk, Ulrich
A1 - Jaumann, Ralf
A1 - Spohn, Tilman
T1 - Supporting Mars exploration BIOMEX in Low Earth Orbit and further astrobiological studies on the Moon using Raman and PanCam technology
JF - Planetary and space science
N2 - The Low Earth Orbit (LEO) experiment Biology and Mars Experiment (BIOMEX) is an interdisciplinary and international space research project selected by ESA. The experiment will be accommodated on the space exposure facility EXPOSE-R2 on the International Space Station (ISS) and is foreseen to be launched in 2013. The prime objective of BIOMEX is to measure to what extent biomolecules, such as pigments and cellular components, are resistant to and able to maintain their stability under space and Mars-like conditions. The results of BIOMEX will be relevant for space proven biosignature definition and for building a biosignature data base (e.g. the proposed creation of an international Raman library). The library will be highly relevant for future space missions such as the search for life on Mars. The secondary scientific objective is to analyze to what extent terrestrial extremophiles are able to survive in space and to determine which interactions between biological samples and selected minerals (including terrestrial, Moon- and Mars analogs) can be observed under space and Mars-like conditions. In this context, the Moon will be an additional platform for performing similar experiments with negligible magnetic shielding and higher solar and galactic irradiation compared to LEO. Using the Moon as an additional astrobiological exposure platform to complement ongoing astrobiological LEO investigations could thus enhance the chances of detecting organic traces of life on Mars. We present a lunar lander mission with two related objectives: a lunar lander equipped with Raman and PanCam instruments which can analyze the lunar surface and survey an astrobiological exposure platform. This dual use of testing mission technology together with geo- and astrobiological analyses will significantly increase the science return, and support the human preparation objectives. It will provide knowledge about the Moon's surface itself and, in addition, monitor the stability of life-markers, such as cells, cell components and pigments, in an extraterrestrial environment with much closer radiation properties to the surface of Mars. The combination of a Raman data base of these data together with data from LEO and space simulation experiments, will lead to further progress on the analysis and interpretation of data that we will obtain from future Moon and Mars exploration missions.
KW - Moon
KW - Mars
KW - Low Earth Orbit
KW - Astrobiology
KW - Instrumentation
KW - Spectroscopy
KW - Biosignature
Y1 - 2012
U6 - https://doi.org/10.1016/j.pss.2012.06.010
SN - 0032-0633
VL - 74
IS - 1
SP - 103
EP - 110
PB - Elsevier
CY - Oxford
ER -