Combined vertical-velocity observations with Doppler lidar, cloud radar and wind profiler

Case studies of combined vertical-velocity measurements of Doppler lidar, cloud radar and wind profiler are presented. The measurements were taken at the Meteorological Observatory, Lindenberg, Germany. Synergistic products are presented that are derived from the vertical-velocity measurements of the three instruments: a comprehensive classification mask of vertically moving atmospheric targets and the terminal fall velocity of water droplets and ice crystals corrected for vertical air motion. It is shown that this combination of instruments can up-value the measurement values of each single instrument and may allow the simultaneous sensing of atmospheric targets and the motion of clear air

Organofluorine chemistry : difluoromethylene motifs spaced 1,3 to each other imparts facial polarity to a cyclohexane ring

This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) and the European Research Council (ERC). The authors acknowledge the EPSRC National Mass Spectrometry Facility (Swansea). D.O’H. thanks the Royal Society for a Wolfson Research Merit Award.2,2-Dimethyl-5-phenyl-1,1,3,3-tetrafluororocyclohexane has been prepared and characterised as an example of a facially polarised cyclohexane containing 1,3 related CF2 groups. The dipolar nature of the ring arises from the axial orientation of two of the C-F bonds pointing in the same direction, and set by the chair conformation of the cyclohexane. This electrostatic profile is revealed experimentally both in the solid-state (X-ray) packing of the rings and by solution (NMR) in different solvents. A computationally derived electrostatic profile of this compound is consistent with a more electronegative and a more electropositive face of the cyclohexane ring. This placing of CF2 groups 1,3 to each other in a cyclohexane ring is introduced as a new design strategy which could be applicable to the preparation of polar hydrophobic cyclohexane motifs.Publisher PDFPeer reviewe

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

Effect of ligand backbone on the selectivity and stability of rhodium hydroformylation catalysts derived from phospholane-phosphites

We thank the Eastman Chemical Company for funding and permission to publish. M.B. thanks the School of Chemistry and EaStCHEM for support.A study on how ligand backbone structure has an impact on selectivity, rate, and catalyst stability of hydroformylation catalysts was prompted by some longer-term stability issues being discovered for a phospholane-phosphite with a [−CH2O−] backbone. A series of phospholane-phosphite ligands were synthesized. Catalysts made in situ from these ligands and [Rh(acac)(CO)2] were found to give iso-butanal selectivities up to 75% at temperatures between 75 and 105 °C: the latter being a benchmark for iso-selectivity in reactions conducted at industrially meaningful temperatures. A racemic rhodium complex of a bidentate phospholane-phosphite from a tropos-biphenol with an extended backbone showed unusually high stability at high temperatures, combined with even better iso-selectivity in propene hydroformylation relative to the original complex. A related ligand with an electron-withdrawing group maintained the unusually high stability and improved activity. Characterization of the precatalysts of type [RhH(CO)2(L)] was accomplished using in situ HPIR spectroscopy and backed up by density functional theory calculations (B3PW91-D3 level) and by NMR studies; the latter showed that the variation of the backbone also had a pronounced impact on the precatalyst structure. A key finding is that it is now possible to prepare phospholane-phosphite ligands that deliver high iso-butanal selectivity and that show no signs of degradation after several days even above typical reaction temperatures. In one stability test, several kilograms of aldehydes were produced with TOF and selectivity being consistent over several days.PostprintPeer reviewe

Combining cloud radar and radar wind profiler for a value added estimate of vertical air motion and particle terminal velocity within clouds

Vertical-stare observations from a 482 MHz radar wind profiler and a 35 GHz cloud radar are combined on the level of individual Doppler spectra to measure vertical air motions in clear air, clouds and precipitation. For this purpose, a separation algorithm is proposed to remove the influence of falling particles from the wind profiler Doppler spectra and to calculate the terminal fall velocity of hydrometeors. The remaining error of both vertical air motion and terminal fall velocity is estimated to be better than 0.1 m s−1 using numerical simulations. This combination of instruments allows direct measurements of in-cloud vertical air velocity and particle terminal fall velocity by means of ground-based remote sensing. The possibility of providing a profile every 10 s with a height resolution of  &lt; 100 m allows further insight into the process scale of in-cloud dynamics. The results of the separation algorithm are illustrated by two case studies, the first covering a deep frontal cloud and the second featuring a shallow mixed-phase cloud.</p

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

Der virtuelle Raum als Double - oder: zur Persistenz hierarchischer Gesellschaftsstruktur im Netz

Der raumsoziologische Beitrag diskutiert, was die mit der Technologie des Internets einhergehende Virtualisierung für eine sich ändernde Gesellschaftsordnung bedeuten kann. Anhand ihres methodologischen RaumZeit-Modells zeigt die Autorin, dass die virtuelle Realität des Internets eine doppelte materiale Gestalt hervorbringt. Als Double ergänzt der virtuelle Raum den realen. Die Ausgangsannahme lautet, dass die bürgerlich-moderne Gesellschaft Raum als Zweidimensionalität und als Behälter sowie Zeit als messbar und linear hervorgebracht hat. Entgegen vielfach geäußerter Einschätzungen revolutioniert das Internet nicht Vorstellungen und Praxis von Raum und Zeit, sondern es perfektioniert die bürgerliche Konstruktion des ideal beherrschbaren Lebens. Der Hypothese folgend, dass die neuen virtuellen Realitäten veränderte Materialitäten etablieren, werden verschiedene Zukunftsszenarien am Beispiel des Geschlechterverhältnisses durchgespielt

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

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

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