59 research outputs found

    MHz free electron laser x-ray diffraction and modeling of pulsed laser heated diamond anvil cell

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    International audienceA new diamond anvil cell experimental approach has been implemented at the European x-ray Free Electron Laser, combining pulsed laser heating with MHz x-ray diffraction. Here, we use this setup to determine liquidus temperatures under extreme conditions, based on the determination of time-resolved crystallization. The focus is on a Fe-Si-O ternary system, relevant for planetary cores. This time-resolved diagnostic is complemented by a finite-element model, reproducing temporal temperature profiles measured experimentally using streaked optical pyrometry. This model calculates the temperature and strain fields by including (i) pressure and temperature dependencies of material properties, and (ii) the heat-induced thermal stress, including feedback effect on material parameter variations. Making our model more realistic, these improvements are critical as they give 7000 K temperature differences compared to previous models. Laser intensities are determined by seeking minimal deviation between measured and modeled temperatures. Combining models and streak optical pyrometry data extends temperature determination below detection limit. The presented approach can be used to infer the liquidus temperature by the appearance of SiO2 diffraction spots. In addition, temperatures obtained by the model agree with crystallization temperatures reported for Fe–Si alloys. Our model reproduces the planetary relevant experimental conditions, providing temperature, pressure, and volume conditions. Those predictions are then used to determine liquidus temperatures at experimental timescales where chemical migration is limited. This synergy of novel time-resolved experiments and finite-element modeling pushes further the interpretation capabilities in diamond anvil cell experiments

    NFDI4Chem: from chemical research data management to digital chemistry

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    This presentation was held at the GDCh-Wissenschaftsforum (WiFo) "Rethinking Chemistry" 2023 in Leipzig.Funding: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under the National Research Data Infrastructure – NFDI4Chem – Projektnummer 441958208

    NMRium: ReactJS component to display and process NMR spectra

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    Software that allows to visualize and process 1D and 2D NMR spectra. Visit https://www.nmrium.org or https://docs.nmrium.org to get more information

    Strong effect of stress on the seismic signature of the post-stishovite phase transition in the Earth’s lower mantle

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    The stishovite to post-stishovite phase transition may modify the scattering of seismic waves by stishovite-bearing rocks in the Earth's lower mantle. A series of continuous compression experiments on sintered polycrystalline stishovite was performed to study the effect of stress on the phase transition. The experimental results show that the phase transition shifts to lower pressures as the magnitude of deviatoric stress increases. Our results further show that the bulk modulus of sintered polycrystalline stishovite differs from that derived from single crystal measurements and decreases at the phase transition. In cold regions, such as subducted slabs, stresses may accumulate and shift the phase transition to a shallower depth. In hot regions with less stress, such as rising plumes, the phase transition is shifted to a greater depth. In addition, the phase transition may have varying seismic signatures depending on the behavior of the grain boundaries in mantle rocks and the micro-stresses present in neighboring grains

    ComPlat/chem-spectra-app: 0.13.4

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    Handle FL SPECTRUM as Emission Only generate combined image when more than 1 jdx fil

    A MHz X-ray diffraction set-up for dynamic compression experiments in the diamond anvil cell

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    An experimental platform for dynamic diamond anvil cell (dDAC) research has been developed at the High Energy Density (HED) Instrument at the European X-ray Free Electron Laser (European XFEL). Advantage was taken of the high repetition rate of the European XFEL (up to 4.5 MHz) to collect pulse-resolved MHz X-ray diffraction data from samples as they are dynamically compressed at intermediate strain rates (≀10 3 s −1 ), where up to 352 diffraction images can be collected from a single pulse train. The set-up employs piezo-driven dDACs capable of compressing samples in ≄340 ”s, compatible with the maximum length of the pulse train (550 ”s). Results from rapid compression experiments on a wide range of sample systems with different X-ray scattering powers are presented. A maximum compression rate of 87 TPa s −1 was observed during the fast compression of Au, while a strain rate of ∌1100 s −1 was achieved during the rapid compression of N 2 at 23 TPa s −1

    Minimum Information Standards in Chemistry: A Call for Better Research Data Management Practices

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    Research data management (RDM) is needed to assist experimental advances and data collection in the chemical sciences. Many funders require RDM because experiments are often paid for by taxpayers and the resulting data should be deposited sustainably for posterity. However, paper notebooks are still common in laboratories and research data is often stored in proprietary and/or dead-end file formats without experimental context. Data must mature beyond a mere supplement to a research paper. Electronic lab notebooks (ELN) and laboratory information management systems (LIMS) allow researchers to manage data better and they simplify research and publication. Thus, an agreement is needed on minimum information standards for data handling to support structured approaches to data reporting. As digitalization becomes part of curricular teaching, future generations of digital native chemists will embrace RDM and ELN as an organic part of their research

    Sektionskonzept Training & Education zur Einrichtung einer Sektion im Verein Nationale Forschungsdateninfrastruktur (NFDI) e.V.

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    Sektionskonzept zur Einrichtung einer Sektion im Verein Nationale Forschungsdateninfrastruktur (NFDI) e.V. Name der Sektion: Training & Education Akronym der Sektion: section-edutrain Ansprechpersonen Sektionseinrichtung: Prof. Dr.-Ing Peter F. Pelz (NFDI4Ing), Prof. Dr. rer. nat. Sonja Herres-Pawlis (NFDI4Chem) Kurzbeschreibung: Datenkompetenz von Anfang an! Damit betonen wir erstens die Wichtigkeit von Bildung in Datenkompetenz aller Stakeholder in allen Bereichen der Forschung und der Hochschullehre. Zweitens zeigt unser Paradigma den Weg zur Nachhaltigkeit von Forschungsdatenmanagement (FDM). Durch “Datenkompetenz von Anfang an” tragen wir zur Weiterentwicklung wissenschaftlicher Methoden und der guten wissenschaftlichen Praxis bei: Bildung in Datenkompetenz ermöglicht, die formale QualitĂ€t der Ressource “Daten” so zu steigern, dass sie sowohl fĂŒr Erkenntnis als auch fĂŒr nachhaltige Lösungen gesellschaftlicher Herausforderungen genutzt werden kann. Dies geschieht durch Transparenz und Nachvollziehbarkeit fĂŒr alle Stakeholder in einem offenen oder auch geschĂŒtzten Datenraum..

    The High Energy Density Scientific Instrument at the European XFEL

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    The European XFEL delivers up to 27000 intense (>1012 photons) pulses per second, of ultrashort (≀50 fs) and transversely coherent X-ray radiation, at a maximum repetition rate of 4.5 MHz. Its unique X-ray beam parameters enable groundbreaking experiments in matter at extreme conditions at the High Energy Density (HED) scientific instrument. The performance of the HED instrument during its first two years of operation, its scientific remit, as well as ongoing installations towards full operation are presented. Scientific goals of HED include the investigation of extreme states of matter created by intense laser pulses, diamond anvil cells, or pulsed magnets, and ultrafast X-ray methods that allow their diagnosis using self-amplified spontaneous emission between 5 and 25 keV, coupled with X-ray monochromators and optional seeded beam operation. The HED instrument provides two target chambers, X-ray spectrometers for emission and scattering, X-ray detectors, and a timing tool to correct for residual timing jitter between laser and X-ray pulses