2,126 research outputs found

    Hypernetwork functional image representation

    Full text link
    Motivated by the human way of memorizing images we introduce their functional representation, where an image is represented by a neural network. For this purpose, we construct a hypernetwork which takes an image and returns weights to the target network, which maps point from the plane (representing positions of the pixel) into its corresponding color in the image. Since the obtained representation is continuous, one can easily inspect the image at various resolutions and perform on it arbitrary continuous operations. Moreover, by inspecting interpolations we show that such representation has some properties characteristic to generative models. To evaluate the proposed mechanism experimentally, we apply it to image super-resolution problem. Despite using a single model for various scaling factors, we obtained results comparable to existing super-resolution methods

    Thermal tides in the Martian middle atmosphere as seen by the Mars Climate Sounder

    Get PDF
    The first systematic observations of the middle atmosphere of Mars (35–80km) with the Mars Climate Sounder (MCS) show dramatic patterns of diurnal thermal variation, evident in retrievals of temperature and water ice opacity. At the time of writing, the data set of MCS limb retrievals is sufficient for spectral analysis within a limited range of latitudes and seasons. This analysis shows that these thermal variations are almost exclusively associated with a diurnal thermal tide. Using a Martian general circulation model to extend our analysis, we show that the diurnal thermal tide dominates these patterns for all latitudes and all seasons

    Tribological properties of duplex plasma oxidised, nitrided and PVD coated Ti-6Al-4V

    Get PDF
    The authors gratefully acknowledge financial support from the UK Technology Strategy Board under Technology Programme project TP/22076, for underpinning research carried out at Sheffield University, on which the work presented in this paper was partially based.Sequential triode plasma oxidation and nitriding have been used to provide enhanced load support for physical vapour deposited (PVD) hard coatings. The diffusion process has been designed to maximise process efficiency and coating adhesion, thereby significantly improving the tribological properties of the Ti–6Al–4V alloy — particularly at high contact pressures. This has been demonstrated using unlubricated linear reciprocating-sliding ball-on-plate wear tests and micro-scratch adhesion testing. Also, surface micro- profilometry, nano/micro-indentation hardness testing, scanning electron microscopy (SEM), energy- dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and glow-discharge optical emission spectroscopy (GDOES) data are presented to corroborate the effect of the several plasma diffusion processes and duplex diffusion/coating combinations discussed here. The results presented show that the novel processing technique developed permits the use of oxygen diffusion in order to obtain relatively large case depths in shorter treatment times without compromising the adhesion strength of subsequently deposited PVD layers.peer-reviewe

    Wiedernutzung von Bioporen in Agrarökosystemen: eine neue Zweifach-Markierungsmethode mit Radionukliden

    Get PDF
    Bioporen als mikrobielle Hotspots bieten Nährstoffe und erlauben schnelleres Wurzelwachstum in den feuchteren Unterboden – aber nur, wenn Pflanzen sie als präferentielle Wurzelkanäle nutzen anstatt den Gesamtboden zu durchwurzeln. Die Wiedernutzung von Wurzel-Bioporen in Fruchtfolgen konnte bislang nicht quantifiziert werden, obwohl von dieser maßgeblich die Relevanz der Bioporen für die Pflanzenernährung abhängt. Sequenzielle Radionuklid-Markierungen und Autoradiographien bieten einen Ansatz zur exakten Quantifizierung wiedergenutzter Biopoeren. In einer Fruchtfolge wurden Vorfrüchte mit Cs-137 und Hauptfrüchte mit C-14 markiert. Die Signale beider Radionuklide können anhand der unterschiedlichen Zerfallsenergien bei bildgebenden Verfahren durch unterschiedlich dicke Abschirmung getrennt werden. In einem Laborversuch wurden je 5 Pflanzen (Cichorium intybus L.; Medicago sativa L.) mit Cs-137 und C-14 markiert und die Exsudation beider Nuklide genutzt, um die Wiedernutzung einer Biopore mittels der Präsenz beider Nuklide im gleichen Wurzelgang zu verifizieren. Beide Arten verlagerten rund 8% des Cs-137 und 40% des C-14 in die Wurzeln. Die erste Autoradiographie an einem Bodenschnitt erfasste den Zerfall von Cs-137 und C-14. Mit sechs Polypropylen-Folien konnte die Strahlung des schwächeren C-14-Nuklids während der zweiten Autoradiographie abgeschirmt werden, sodass nur Cs-137 erfasst wurde. Mittels Bildbearbeitung konnten beide Bilder deckungsgleich übereinandergelegt und von einander subtrahiert werden, um das C-14-Signal zu errechnen. Die getrennten C-14- und Cs-137-Verteilungen repräsentieren die Verteilung der Wurzeln bzw. Bioporen aus Vor- und Hauptfrucht in einer Bodentiefe. Neben diesem Ergebnis könnte dieser Ansatz hilfreich sein, um die Exsudation von Photosynthese-Produkten (C-14) bzw. gelösten Stoffen (Cs-137) in der Rhizosphäre zu visualisieren

    An investigation into the effect of Triode Plasma Oxidation (TPO) on the tribological properties of Ti6Al4V

    Get PDF
    The authors gratefully acknowledge the UK Technology Strategy Board for financial support under the collaborative project LIB-TEC, project No TP 22076.Improving the tribological properties of titanium alloys has been the subject of extensive research for many years. A number of thermochemical processes have been developed for that purpose. In this study, surface hardening of Ti6Al4V is achieved by Triode Plasma Oxidation (TPO) which differs from conventional diode plasma treatments through the use of a third electrode; a negatively biased tungsten filament to enhance the ionisation levels in the plasma. The resultant surface generally consists of a top oxide layer with an oxy- gen diffusion zone lying immediately underneath it. The effects of process parameters such as substrate tem- perature, current density and oxygen partial pressure have been investigated. Surface hardness measurements at various indentation loads were carried out to assess the changes in hardness with depth across the diffusion layer. The hardness profiles obtained confirmed the gradual decrease in hardness with treatment depth and provided an indication of the thickness of the hardened layer produced. Ball-on-plate reciprocating sliding wear data and glancing angle XRD analyses of the oxidised samples are also presented. The results indicate that a harder and deeper case is achieved at both high substrate temperature and high oxygen partial pressure. Furthermore, XRD data show that the substrate temperature strongly affects the structure of the oxide layer produced. All TPO-treated samples exhibit significantly better wear performance compared to the untreated material.peer-reviewe
    • …
    corecore