1,660 research outputs found

    Project Oriented European Union Funds

    Get PDF
    Fundusze Unii Europejskiej o ukierunkowaniu tematycznymProject Oriented European Union Fund

    Rozwój rynku elektromobilności w Polsce. Dylematy i wyzwania

    Get PDF
    The article deals with issues related to the dilemmas and challenges faced by Poland in electromobility development. Research is focused on legal solutions that do not function in social reality and problems faced by potential owners of electric vehicles.Artykuł podejmuje zagadnienia związane z dylematami i wyzwaniami stojącymi przez Polską w zakresie rozwoju elektromobilności w naszym kraju. Uwaga badawcza skoncentrowana jest na rozwiązania prawne, które nie funkcjonują w społecznej rzeczywistości, a także problemy, na jakie natrafiają potencjalni właściciele pojazdów elektrycznych

    The Controversies Surrounding the Treaty of Lisbon

    Get PDF
    Kontrowersje wokół Traktatu lizbońskiegoThe Controversies Surrounding the Treaty of Lisbo

    A valid method of gas foil bearing parameter estimation: A model anchored on experimental data

    Get PDF
    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Gas foil bearings are a smart green technology and suitable for the next generation of small turbo machinery e.g. turbochargers, micro gas turbines, range extenders and compressors of fuel cells. A combination of low power loss, high speed operation and the omission of an oil system are the major advantages. To enable access to this technology, it is essential to evaluate critical speeds and onset speeds of subharmonic vibration of the rotor system in the first design stage. Hence, robust and valid models are necessary, which correctly describe the fluid structure interaction between the lubrication film and the elastic bearing structure. In the past three decades several experimental and numerical investigations of bearing parameters have been published. But the number of sophisticated models is small and there is still a lack of validation towards experimental works. To make it easy for designers dealing with this issue, the bearing parameters are often linearised about certain operating points. In this paper a method for calculating linearised bearing parameters (stiffness and damping) of gas foil bearing is presented. Experimental data are used for validation of the model. The linearised stiffness and damping values are calculated using a perturbation method. The pressure field is coupled with a two-dimensional plate model, while the non-linear bump structure is simplified by a link-spring model. It includes Coulomb friction effects inside the elastic corrugated structure and captures the interaction between the single bumps. For solving the separated perturbed Reynolds equation a static stiffness is used for the 0. order equation (stationary case) and a dynamic stiffness is applied for 1. order equation (dynamic case). Therefore, an additional dynamic structural model is applied to calculate the dynamic stiffness. The results depend on the load level and friction state of each bump. Different case studies including the impact of clearance, frictional contacts and the comparison of a linear and non-linear structure are carried out for infinitesimal perturbations. The results show, that the linear structure underestimates main and cross-coupling effects. The impact of the clearance is notable, while the impact of the overall frictional contacts is small due to relatively small loadings. The infinitely small perturbation model is adapted to the experimental setup by using a superposition of two resulting bearing parameters identifications of two total loadings including shaker forces. Due to this adaptation a good correlation with the experimental results of the bearing parameters is achieved

    An Amorphous Teflate Doped Aluminium Chlorofluoride: A Solid Lewis‐Superacid for the Dehydrofluorination of Fluoroalkanes

    Get PDF
    An anion-doped aluminium chlorofluoride AlCl0.1F2.8(OTeF5)0.1 (ACF-teflate) was synthesized. The material contains pentafluoroorthotellurate (teflate) groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR-IR spectra of adsorbed CD3CN reveal a blue-shift of the adsorption band by 73 cm−1, which is larger than the shift for SbF5. Remarkably, ACF-teflate catalyzes dehydrofluorination reactions of monofluoroalkanes to yield olefins in C6D6. In these cases, no Friedel-Crafts products were formed.German Research Foundation http://dx.doi.org/10.13039/501100001659Diamond Light Source http://dx.doi.org/10.13039/100011889German Research Foundation http://dx.doi.org/10.13039/501100001659Peer Reviewe

    Large spin systematics in CFT

    Get PDF
    20 pages; v2: version published in JHEPUsing conformal field theory (CFT) arguments we derive an infinite number of constraints on the large spin expansion of the anomalous dimensions and structure constants of higher spin operators. These arguments rely only on analiticity, unitarity, crossing-symmetry and the structure of the conformal partial wave expansion. We obtain results for both, perturbative CFT to all order in the perturbation parameter, as well as non-perturbatively. For the case of conformal gauge theories this provides a proof of the reciprocity principle to all orders in perturbation theory and provides a new "reciprocity" principle for structure constants. We argue that these results extend also to non-conformal theories.Peer reviewe

    An Amorphous Teflate Doped Aluminium Chlorofluoride: A Solid Lewis‐Superacid for the Dehydrofluorination of Fluoroalkanes

    Get PDF
    An anion‐doped aluminium chlorofluoride AlCl0.1F2.8(OTeF5)0.1 (ACF‐teflate) was synthesized. The material contains pentafluoroorthotellurate (teflate) groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR‐IR spectra of adsorbed CD3CN reveal a blue‐shift of the adsorption band by 73 cm−1, which is larger than the shift for SbF5. Remarkably, ACF‐teflate catalyzes dehydrofluorination reactions of monofluoroalkanes to yield olefins in C6D6. In these cases, no Friedel‐Crafts products were formed
    corecore