Identification and Environmental Assessments for Different Scenarios of Repurposed Decommissioned Wind Turbine Blades

The rapidly growing wind industry poses a fundamental problem for wind turbine blade (WTB) disposal in many areas of the world. WTBs are primarily manufactured from composites consisting of a thermoset matrix and reinforcing fibers. Currently, there are no economically viable recycling technologies available for such large-scale composite products. Thus, other treatment strategies for disposed WTBs have to be considered. This study explores the repurpose of WTBs as a promising alternative approach from a processual and technological point of view. For this purpose, the study is guided by the categorization into four different types of repurposed applications: high-loaded complete structure (T1), low-loaded complete structure (T2), high-loaded segmented structure (T3), and low-loaded segmented structure (T4). A three-dimensional CAD model of an Enercon-40/500 (E40) wind turbine blade is derived in a reverse engineering procedure to obtain knowledge about the actual geometry of the WTB. Based on the design, three ecosystems of product scenarios (S) with different manufacturing technologies involved are investigated: a climbing tower (S1), a playground (S2) and the combination of a photovoltaic (PV)-floating pontoon, and a lounger (S3). A screening life cycle assessment (LCA) is conducted to evaluate the three repurposed scenarios according to environmental aspects. It is shown that the repurpose of E40 WTB composite material can reduce the environmental impact and leads to significant resource savings in relation to a reference product of similar quality. A particularly high saving potential is identified for the substitution of emission-intensive materials in construction applications. Furthermore, it is found that transport processes are the primary contributor to the environmental impact of repurposed applications

Artificial Metalloenzymes as Catalysts for Oxidative Lignin Degradation

We report novel artificial metalloenzymes (ArMs), containing tris­(pyridylmethyl)­amine (TPA), for the atom economic oxidation of lignin β-O-4 model compounds, using hydrogen peroxide. The protein scaffold alters the selectivity of the reaction from a low yielding cleavage reaction when using the parent Fe-tpa complex to a high yielding benzylic alcohol oxidation when using the complex incorporated into a protein scaffold, SCP-2L A100C. Engineering the protein scaffold to incorporate glutamic acid was found to improve the ArM activity, showing that rational design of the protein environment using metal binding amino acids can be a first step toward improving the overall activity of an artificial metalloenzyme

Static dipole polarizability of C70 fullerene

The electronic and vibrational contributions to the static dipole polarizability of C70 fullerene are determined using the finite-field method within the density functional formalism. Large polarized Gaussian basis sets augmented with diffuse functions are used and the exchange-correlation effects are described within the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA). The calculated polarizability of C70 is 103 Angstrom^3, in excellent agreement with the experimental value of 102 Angstrom^3, and is completely determined by the electronic part, vibrational contribution being negligible. The ratio of polarizabilities of C70 and C60 is 1.26. The comparison of polarizability calculated with only local terms (LDA) in the PBE functional to that obtained with PBE-GGA shows that LDA is sufficient to determine the static dipole polarizability of C70.Comment: IOP style, 1 figur

DFT investigation of 3d transition metal NMR shielding tensors in diamagnetic systems using the gauge-including projector augmented-wave method

We present a density functional theory based method for calculating NMR shielding tensors for 3d transition metal nuclei using periodic boundary conditions. Calculations employ the gauge-including projector augmented-wave pseudopotentials method. The effects of ultrasoft pseudopotential and induced approximations on the second-order magnetic response are intensively examined. The reliability and the strength of the approach for 49Ti and 51V nuclei is shown by comparison with traditional quantum chemical methods, using benchmarks of finite organometallic systems. Application to infinite systems is validated through comparison to experimental data for the 51V nucleus in various vanadium oxide based compounds. The successful agreement obtained for isotropic chemical shifts contrasts with full estimation of the shielding tensor eigenvalues, revealing the limitation of pure exchange-correlation functionals compared to their exact-exchange corrected analogues.Comment: 56 page

Global hybrids from the semiclassical atom theory satisfying the local density linear response

We propose global hybrid approximations of the exchange-correlation (XC) energy functional which reproduce well the modified fourth-order gradient expansion of the exchange energy in the semiclassical limit of many-electron neutral atoms and recover the full local density approximation (LDA) linear response. These XC functionals represent the hybrid versions of the APBE functional [Phys. Rev. Lett. 106, 186406, (2011)] yet employing an additional correlation functional which uses the localization concept of the correlation energy density to improve the compatibility with the Hartree-Fock exchange as well as the coupling-constant-resolved XC potential energy. Broad energetical and structural testings, including thermochemistry and geometry, transition metal complexes, non-covalent interactions, gold clusters and small gold-molecule interfaces, as well as an analysis of the hybrid parameters, show that our construction is quite robust. In particular, our testing shows that the resulting hybrid, including 20\% of Hartree-Fock exchange and named hAPBE, performs remarkably well for a broad palette of systems and properties, being generally better than popular hybrids (PBE0 and B3LYP). Semi-empirical dispersion corrections are also provided.Comment: 12 pages, 4 figure

Wildfire smoke triggers cirrus formation: lidar observations over the eastern Mediterranean

The number of intense wildfires may increase further in upcoming years as a consequence of climate change. It is therefore necessary to improve our knowledge about the role of smoke in the climate system, with emphasis on the impact of smoke particles on the evolution of clouds, precipitation, and cloud radiative properties. Presently, one key aspect of research is whether or not wildfire smoke particles can initiate cirrus formation. In this study, we present lidar observations over Limassol, Cyprus, from 27 October to 3 November 2020, when extended wildfire smoke fields crossed the Mediterranean Basin from Portugal to Cyprus. We found strong evidence that aged smoke (organic aerosol particles) originating from wildfires in North America triggered significant ice nucleation at temperatures from −47 to −53 ∘C and caused the formation of extended cirrus layers. The observations suggest that the ice crystals were nucleated just below the tropopause in the presence of smoke particles serving as ice-nucleating particles (INPs). The main part of the 2–3 km thick smoke layer was, however, in the lower stratosphere just above the tropopause. With actual radiosonde observations of temperature and relative humidity and lidar-derived smoke particle surface area concentrations used as starting values, gravity wave simulations show that the lofting of air by 100–200 m is sufficient to initiate significant ice nucleation on the smoke particles, leading to ice crystal number concentrations of 1–100 L−1.</p

Opening a new window to other worlds with spectropolarimetry

A high level of diversity has already been observed among the planets of our own Solar System. As such, one expects extrasolar planets to present a wide range of distinctive features, therefore the characterisation of Earth- and super Earth-like planets is becoming of key importance in scientific research. The SEARCH (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) mission proposal of this paper represents one possible approach to realising these objectives. The mission goals of SEARCH include the detailed characterisation of a wide variety of exoplanets, ranging from terrestrial planets to gas giants. More specifically, SEARCH will determine atmospheric properties such as cloud coverage, surface pressure and atmospheric composition, and may also be capable of identifying basic surface features. To resolve a planet with a semi major axis of down to 1.4AU and 30pc distant SEARCH will have a mirror system consisting of two segments, with elliptical rim, cut out of a parabolic mirror. This will yield an effective diameter of 9 meters along one axis. A phase mask coronagraph along with an integral spectrograph will be used to overcome the contrast ratio of star to planet light. Such a mission would provide invaluable data on the diversity present in extrasolar planetary systems and much more could be learned from the similarities and differences compared to our own Solar System. This would allow our theories of planetary formation, atmospheric accretion and evolution to be tested, and our understanding of regions such as the outer limit of the Habitable Zone to be further improved.Comment: 23 pages, accepted for publication in Experimental Astronom

The DACAPO-PESO campaign: Dynamics, Aerosol, Cloud and Precipitation Observations in the Pristine Environment of the Southern Ocean: An overview

This article gives an overview of the DACAPO-PESO field experiment, which has taken place in Punta Arenas, Chile, from November 2018 to November 2021, and showcases first exciting research results that have already emerged from it.In diesem Artikel wird ein Überblick über das DACAPO-PESO Experiment gegeben, welches von November 2018 bis November 2021 in Punta Arenas, Chile, stattgefunden hat. Außerdem werden erste spannende Forschungsergebnisse vorgestellt, die bereits daraus gewonnen wurden

Long-term validation of Aeolus L2B wind products at Punta Arenas, Chile, and Leipzig, Germany

Ground-based observations of horizontal winds have been performed at Leipzig (51.35∘ N, 12.43∘ E), Germany, and at Punta Arenas (53.15∘ S, 70.91∘ W), Chile, in the framework of the German initiative EVAA (Experimental Validation and Assimilation of Aeolus observations) with respect to the validation of the Mie and Rayleigh wind products of Aeolus (L2B data). In Leipzig, at the Leibniz Institute for Tropospheric Research (TROPOS), radiosondes have been launched for the Aeolus overpasses on each Friday (ascending orbit) since the middle of May 2019. In Punta Arenas, scanning Doppler cloud radar observations have been performed in the framework of the DACAPO-PESO campaign (dacapo.tropos.de) for more than 3 years from the end of 2018 until the end of 2021 and could be used to validate Aeolus measurements on its ascending and descending orbits. We present two case studies and long‐term statistics of the horizontal winds derived with the ground-based reference instruments compared to Aeolus horizontal line-of-sight (HLOS) winds. The wind products of Aeolus considered are the Mie cloudy and Rayleigh clear products. It was found that the deviation of the Aeolus HLOS winds from the ground reference is usually of Gaussian shape, which allowed the use of the median bias and the scaled median absolute deviation (MAD) for the determination of the systematic and random errors of Aeolus wind products, respectively. The case study from August 2020 with impressive atmospheric conditions at Punta Arenas shows that Aeolus is able to capture strong wind speeds of up to more than 100 m s−1. The long-term validation was performed in Punta Arenas covering the period from December 2018 to November 2021 and in Leipzig from May 2019 until September 2022. This analysis showed that the systematic error of the Aeolus wind products could be significantly lowered during the mission lifetime with the changes introduced into the processing chain (different versions are called baselines). While in the early mission phase, systematic errors of more than 2 m s−1 (absolute values) were observed for both wind types (Mie and Rayleigh), these biases could be reduced with the algorithm improvements, such as the introduction of the correction for temperature fluctuations at the main telescope of Aeolus (M1 temperature correction) with Baseline 09. Hence, since Baseline 10, a significant improvement in the Aeolus data was found, leading to a low systematic error (close to 0 m s−1) and similar values for the midlatitudinal sites in both hemispheres. The random errors for both wind products were first decreasing with an increasing baseline but later increasing again due to performance losses of the Aeolus lidar instrument. Nevertheless, no significant increase in the systematic error in the Aeolus wind products was found. Thus, one can conclude that the uncertainty introduced by the reduced atmospheric return signal received by Aeolus mostly affects the random error. Even when considering all the challenges during the mission, we can confirm the general validity of Aeolus observations during its lifetime. Therefore, this space explorer mission could demonstrate that it is possible to perform active wind observations from space with the applied technique.</p