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  • IOP Publishing  (6)
  • 2020-2024  (6)
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  • IOP Publishing  (6)
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  • 2020-2024  (6)
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  • 1
    Online-Ressource
    Online-Ressource
    IOP Publishing ; 2020
    In:  Journal of Physics: Conference Series Vol. 1618, No. 4 ( 2020-09-01), p. 042009-
    In: Journal of Physics: Conference Series, IOP Publishing, Vol. 1618, No. 4 ( 2020-09-01), p. 042009-
    Kurzfassung: Within the project “Windy Cities” the economic use of small wind turbines in urban areas is investigated in Tübingen, Germany. This test-site contains complex terrain, forested areas and various types of buildings making the local wind field more turbulent and complex. To avoid damages and reduced life times of small wind turbines caused by high turbulence a detailed prediction of the wind field is essential in the present study. This is done using CFD. The scope of this study is the validation of the setup including terrain and vegetation. For this, on-site planar wind field LiDAR data are utilized to define the inflow boundary condition for highly resolved Detached Eddy Simulations (DES) using ANSYS Fluent. The required preprocessing steps of the LiDAR data are explained in detail and their assumptions, which are made to interpolate the data onto the numerical inflow plane. Since the inflow region is covered by forested zones a forest model is introduced with a local tree height adaption based on Laser scan data. LiDAR data, which are measured further downstream, are used to validate the forest model. Simulations with and without the considered forest are compared to investigate the influence of the forested region.
    Materialart: Online-Ressource
    ISSN: 1742-6588 , 1742-6596
    Sprache: Unbekannt
    Verlag: IOP Publishing
    Publikationsdatum: 2020
    ZDB Id: 2166409-2
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Online-Ressource
    Online-Ressource
    IOP Publishing ; 2021
    In:  Publications of the Astronomical Society of the Pacific Vol. 133, No. 1019 ( 2021-01-01), p. 014501-
    In: Publications of the Astronomical Society of the Pacific, IOP Publishing, Vol. 133, No. 1019 ( 2021-01-01), p. 014501-
    Kurzfassung: In this paper we investigate how implementing machine learning could improve the efficiency of the search for Trans-Neptunian Objects (TNOs) within Dark Energy Survey (DES) data when used alongside orbit fitting. The discovery of multiple TNOs that appear to show a similarity in their orbital parameters has led to the suggestion that one or more undetected planets, an as yet undiscovered “Planet 9”, may be present in the outer solar system. DES is well placed to detect such a planet and has already been used to discover many other TNOs. Here, we perform tests on eight different supervised machine learning algorithms, using a data set consisting of simulated TNOs buried within real DES noise data. We found that the best performing classifier was the Random Forest which, when optimized, performed well at detecting the rare objects. We achieve an area under the receiver operating characteristic (ROC) curve, (AUC) = 0.996 ± 0.001. After optimizing the decision threshold of the Random Forest, we achieve a recall of 0.96 while maintaining a precision of 0.80. Finally, by using the optimized classifier to pre-select objects, we are able to run the orbit-fitting stage of our detection pipeline five times faster.
    Materialart: Online-Ressource
    ISSN: 0004-6280 , 1538-3873
    Sprache: Unbekannt
    Verlag: IOP Publishing
    Publikationsdatum: 2021
    ZDB Id: 2003100-2
    ZDB Id: 2207655-4
    SSG: 16,12
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Online-Ressource
    Online-Ressource
    IOP Publishing ; 2023
    In:  Journal of Cosmology and Astroparticle Physics Vol. 2023, No. 10 ( 2023-10-01), p. 028-
    In: Journal of Cosmology and Astroparticle Physics, IOP Publishing, Vol. 2023, No. 10 ( 2023-10-01), p. 028-
    Kurzfassung: We present the integrated 3-point correlation functions (3PCF) involving both the cosmic shear and the galaxy density fields. These are a set of higher-order statistics that describe the modulation of local 2-point correlation functions (2PCF) by large-scale features in the fields, and which are easy to measure from galaxy imaging surveys. Based on previous works on the shear-only integrated 3PCF, we develop the theoretical framework for modelling 5 new statistics involving the galaxy field and its cross-correlations with cosmic shear. Using realistic galaxy and cosmic shear mocks from simulations, we determine the regime of validity of our models based on leading-order standard perturbation theory with an MCMC analysis that recovers unbiased constraints of the amplitude of fluctuations parameter A s and the linear and quadratic galaxy bias parameters b 1 and b 2 . Using Fisher matrix forecasts for a DES-Y3-like survey, relative to baseline analyses with conventional 3×2PCFs, we find that the addition of the shear-only integrated 3PCF can improve cosmological parameter constraints by 20–40%. The subsequent addition of the new statistics introduced in this paper can lead to further improvements of 10–20%, even when utilizing only conservatively large scales where the tree-level models are valid. Our results motivate future work on the galaxy and shear integrated 3PCFs, which offer a practical way to extend standard analyses based on 3×2PCFs to systematically probe the non-Gaussian information content of cosmic density fields.
    Materialart: Online-Ressource
    ISSN: 1475-7516
    Sprache: Unbekannt
    Verlag: IOP Publishing
    Publikationsdatum: 2023
    ZDB Id: 2104147-7
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Online-Ressource
    Online-Ressource
    IOP Publishing ; 2020
    In:  Journal of Physics: Conference Series Vol. 1618 ( 2020-09), p. 042005-
    In: Journal of Physics: Conference Series, IOP Publishing, Vol. 1618 ( 2020-09), p. 042005-
    Materialart: Online-Ressource
    ISSN: 1742-6588 , 1742-6596
    Sprache: Unbekannt
    Verlag: IOP Publishing
    Publikationsdatum: 2020
    ZDB Id: 2166409-2
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Online-Ressource
    Online-Ressource
    IOP Publishing ; 2021
    In:  Multifunctional Materials Vol. 4, No. 1 ( 2021-03-01), p. 014002-
    In: Multifunctional Materials, IOP Publishing, Vol. 4, No. 1 ( 2021-03-01), p. 014002-
    Kurzfassung: Mineral deposition in biological systems is often templated by organic matrices including proteins directing the nucleation and growth of bioceramics by interacting with early stage species of the mineralization process or coordinating specific facets of the forming crystal. Structurally, charged surface patches are a characteristic motif of biomineralization-associated proteins, which are able to accumulate and bind ions from the surrounding media and, therefore, initiate, promote or inhibit mineralization. Controlled protein engineering enables the manipulation and control of bioinspired in vitro precipitation systems, and thus not only opens prospects for the design of environmentally benign synthetic strategies towards hierarchically structured functional materials, but also enhances the understanding of fundamental interaction mechanisms in biomineralization processes. Here, two recombinant variants of the spider silk protein ADF4 were engineered with oppositely charged peptide tags. Both were processed into micrometer-sized particles and investigated for their influence on manganese carbonate mineralization. Micro- and nano-structured manganese carbonate represents an attractive material for diverse applications including catalysis and wastewater treatment. While both types of spider silk particles were incorporated into the mineral structure, the positively tagged proteins appeared to interact more strongly with the formed manganese carbonate crystals than their negatively charged counterparts. Combination of the spider silk particles and poly(acrylic acid) (PAA), a water-soluble structure-directing agent associated with the stabilization of amorphous precursor phases in carbonates, resulted in the formation of film-like non-equilibrium structures of MnCO 3 entrapping the spider silk particles. With the aim to gain mechanistic insights and to elucidate the interaction between the different components involved in the mineralization process, we studied the interplay between PAA, positively or negatively tagged spider silk particles, and Mn(II) ions by time-resolved dynamic light scattering. The here used set-up affords the possibility to identify control strategies for the template-mediated mineralization of manganese carbonate.
    Materialart: Online-Ressource
    ISSN: 2399-7532
    Sprache: Unbekannt
    Verlag: IOP Publishing
    Publikationsdatum: 2021
    ZDB Id: 2984925-1
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    In: Nuclear Fusion, IOP Publishing, Vol. 62, No. 4 ( 2022-04-01), p. 042022-
    Kurzfassung: We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases.
    Materialart: Online-Ressource
    ISSN: 0029-5515 , 1741-4326
    Sprache: Unbekannt
    Verlag: IOP Publishing
    Publikationsdatum: 2022
    ZDB Id: 2037980-8
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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