10,101 research outputs found
Multi-dimensional Morse Index Theorems and a symplectic view of elliptic boundary value problems
No full textMorse Index Theorems for elliptic boundary value problems in multi-dimensions are proved under various boundary conditions. The theorems work for star-shaped domains and are based on a new idea of measuring the "oscillation" of the trace of the set of solutions on a shrinking boundary. The oscillation is measured by formulating a Maslov index in an appropriate Sobolev space of functions on this boundary. A fundamental difference between the cases of Dirichlet and Neumann boundary conditions is exposed through a monotonicity that holds only in the former case
An examination of Kolmogorov's refined similarity hypotheses for active scalar in compressible turbulence
No full textUsing direct numerical simulations of isotropic compressible turbulence driven by large-scale solenoidal force (up to 10243 grid points), we examine the Kolmogorov’s refined similarity hypotheses (RSH) as applied to active scalar, i.e. temperature, with Prandtl number of order one. The three-dimensional compressible Navier-Stokes equations are solved by adopting a hybrid method for space and a second-order Runge-Kutta technique for time. The stationary turbulent Mach number,Mt, and Taylor microscale Reynolds number, Reλ, vary from 0.3 to 1.0 and 123 to 255, respectively. The two-dimensional contours of temperature dissipation field show that at low Mt the field is dominated by vortices structures while at high Mt it is full of small-scale shocklets structures. When Reλ increases, the random distribution of shocklets is reinforced, and thus, the field tends to local isotropy at small scales. According to the scaling exponents obtained in our simulations, the probability distribution of the normalized temperature increment is basically the same for the temperature fields, however, they are not close to Gaussian. Furthermore, the usage of the scaling exponents from standard RSH theory [1,2] shows that the new probability distribution behaves rather different, suggesting the failure of RSH for temperature
Analyse und Bewertung der sprachwissenschaftlichen Standards aktueller Forschungen traditioneller Art zur "alteuropäischen Hydronymie" aus der Perspektive der heutigen Indogermanistik
No full textThis paper is a response to an article in the journal Acta Linguistica Lithuanica 62–63 (2011), whose author argues partially quite unscientifically. This paper will show the deficiencies of knowledge the other article’s author betrays as far as historical-comparative linguistics in general and Indo-European linguistics especially are concerned. As a conclusion it must be stated that all the results the other author has achieved in the field of ‘Old European Hydronymy’ by using research methods outdated for decades will have to be reevaluated applying to them modern Indo-European linguistics. Only after this task will have been accomplished, one will be able to tell which of that author‘s works and results will be safe for further use
One-step controllable fabrication of 3D structured self-standing Al<sub>3</sub>Ni<sub>2</sub>/Ni electrode through molten salt electrolysis for efficient water splitting
No full textExploring more efficient and low-cost electrocatalysts to replace platinum (Pt) is highly desired to promote the practical hydrogen production through water splitting. Herein, a facile and effective strategy is proposed to fabricate self-standing Al3Ni2/Ni electrode with controlled phase composition and surface morphology, which is obtained by one-step electrochemical reduction of Al3+ on commercially available nickel in eutectic NaCl-KCl melt. Different from previously reported approaches, uniform Al3Ni2 monolith catalyst can directly grow onto Ni substrate. The deposit possesses unique three-dimensional (3D) cauliflower-like morphology comprising of nano- and microparticles due to the rapid nucleation rate during molten salt electrolysis. The as-fabricated Al3Ni2/Ni electrode can be directly used as the cathode to catalyze Hydrogen evolution reaction (HER). Impressively, it exhibits remarkable HER activity comparable to commercial Pt, including a low overpotential of 83.4 mV for a current density of 10 mA cm−2, a small Tafel slope of 40.7 mV dec-1, and excellent long-term stability over 36 h of continuous HER operation in 0.5 M H2SO4 solution. The intrinsic catalytic ability of Al3Ni2 with the unique hierarchical structure of nano/microsized grains can offer multiple effects, including massive exposed active sites, enhanced charge transfer and mass transport, and fast gas releasing that synergistically contribute to improving the electrocatalytic performance of HER. This work represents a highly promising approach to the design and one-step controllable fabrication of efficient and self-standing base metal electrode for electrocatalytic hydrogen production.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Yongxiang Yan
Kurzer Überblick über die Siedlungsnamen im Kreis Sangerhausen
No full textWhereas in Sachsen, Brandenburg or Schleswig-Holstein all place names are worked on, the examination of the meaning of many place names in Sachsen-Anhalt is still a desideratum. This article surveys the meaning of the older place names in the former Landkreis Sangerhausen (southern Sachsen-Anhalt) – current and deserted place names – in the territorial boarders of the period 1990 –2007, as well as their level of research based on the author\\u27\u27s Master\\u27\u27s degree thesis of the winter semester 2007/08. The author gathered all documentary evidences that could be found in the written sources of regionally specific source books from the first naming in the sources to the 15th / 16th century. The reseach revealed that the oldest names were to be found near the rivers and on most fertile grounds. These place names were mostly derivatives, but one can find also some very old compounds
Wiedergabe von Personennamen in der gegenwärtigen polnischen Übersetzung der „Kinder- und Hausmärchen“ der Brüder Grimm
No full textThe Children’s and Household Tales by Brothers Grimm are world famous thanks to their translations in many languages. In the presented article its author refers to her own translation of the Grimms’ folktale collection (published in 2010) and discusses translation decisions referring to selected personal names. The functional typology of literary names by H. Birus (1987) builds a starting point for detailed translation analyses in three categories: speaking, classifying and embodying names. It is surprising that in a translation which was intended by its author to be philologically faithful the majority of anthroponyms was not transcribed (in order to render their foreign character) but became domesticated by means of adaptation, substitution and literal translation. It proves that in a literary piece of work proper names fulfill complex functions which makes the translator choose different translation methods to render them
Mearuring the orientation and roation rate of 3D printed particles in turbulence
No full textThe orientation distribution and rotations of anisotropic particles in turbulent flows play a key role in many applications ranging from icy clouds to papermaking and drag reduction in pipe flow. However, experimental access to time-resolved orientations of anisotropic particles has not been easy to achieve. The use of 3D printing opens up the possibility to fabricate a wide range of particle shapes with smallest dimension down to 300 μm. So far, we have printed rods, crosses, jacks, triads, tetrads and helical particle shapes. We extract particle orientations from stereoscopic video images using a method of least squares optimization in Euler angle space. We find that in turbulence, the orientation and rotation-rate of many particles can be understood using a simple picture of alignment of both the vorticity and a long axis of the particle with the Lagrangian stretching direction of the flow
Das slawisch-deutsche Toponym in lexikographischer Sicht
No full textThe author presents dictionaries of toponyms from the Slavic-German borderland. The conceptions of German, Czech and Polish dictionaries are presented. He considers the method of toponym-settlement identification better and more transparent than the method of establishing one entry and common linguistic explanation for names of varied origin. The author emphasizes the necessity for research of related names from the various Slavic languages
Hundert Jahre Namn och Bygd: Tendenzen und Entwicklungslinien
No full textIn 2012, Namn och bygd, which is considered to be the world’s oldest specialised journal for place-name research, is publishing its one-hundredth issue. In this essay, the author attempts a survey of key aspects of the journal, and changes affecting it, since 1913. This includes comments on its aims, its editors and associate editors, contributing authors from different academic disciplines, contacts with other countries within and beyond the Nordic region, different sections of the journal and, of course, the scholarly content of Namn och bygd over the hundred years of its history
Additions and corrections to my Bavarian-Slavic phonetic transcrip- tion apparatus (with a glossary of names) – Slavia Tirolens: (Main Topic)
No full textIn this article, the author presents some adjustments and corrections to the apparatus of sound changes proposed in his previous papers (Slavia Tirolensis I–III). The updates have become necessary due to additional data from mediaeval toponomastic loans from Slavic into Bavarian in East Tyrol. The relevant data is also included in the article. The apparatus enables a step-by-step identification of each sound change undergone by such loans from the borrowed form until today’s local pronunciation of the names
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