2,624 research outputs found
Viscous spreading of non-Newtonian gravity currents on a plane
No full textA gravity current originated by a power-law viscous fluid propagating on a horizontal rigid plane below a fluid of lower density is examined. The intruding fluid is considered to have a pure Ostwald power-law constitutive equation. The set of equations governing the flow is presented, under the assumption of buoyancy-viscous balance and negligible inertial forces. The conditions under which the above assumptions are valid are examined and a self-similar solution in terms of a nonlinear ordinary differential equation is derived. For the release of a time-variable volume of fluid, the shape of the gravity current is determined numerically using an approximate analytical solution derived close to the current front as a starting condition. A closed-form analytical expression is derived for the special case of the release of a fixed volume of fluid. The space-time development of the gravity current is discussed for different flow behavior indexes
Who is the author of the 1876 Stefano manuscript?
No full textFor over one hundred years the Stefano manuscript was a private document in the possession of the Baccich family and descendants. It told a story of the 1875 Stefano shipwreck as narrated by the shipwreck survivor and the founding family patriarch Miho Baccich. In these circumstances the question of authorship of the manuscript was immaterial and did not arise as an issue. However, with the publication of the manuscript the author‟s name, or names, need to be formally attributed to it. It turns out that this is not such a clear-cut matter.
As we shall see, all informed sources attributed the authorship, and the ownership, of the manuscript to Miho Baccich. But the manuscript itself was written by Canon Stjepan Skurla – a priest from Miho‟s hometown of Dubrovnik. The question then arises: should Skurla also be considered as an author of the manuscript, or, even as the sole author (as some would have it)
Viscous spreading of non-Newtonian gravity currents in radial geometry
No full textA gravity current originated by a power-law viscous fluid propagating in axisymmetric geometry on a horizontal rigid plane below a fluid of lesser density is examined. The intruding fluid is considered to have a pure power-law constitutive equation. The set of equations governing the flow is presented, under the assumption of buoyancy-viscous balance and negligible inertial forces. The conditions under which the above assumptions are valid are examined and a self-similar solution in terms of a nonlinear ordinary differential equation is derived for the release of a fixed volume of fluid. The space-time development of the gravity current is discussed for different flow behavior indexes
Generating and scaling fractional Brownian motion on finite domains
No full textPower variograms of statistically isotropic or anisotropic fractal fields (common in earth science) are weighted integrals of variograms representing statistically homogeneous fields (modes) having mutually uncorrelated increments. Large- and small-scale cutoffs were previ-ously assumed proportional to length scales of the sampling window and data support. We verify this assumption numerically for two-dimensional isotropic fractional Brownian motion (fBm). It was previously concluded semi-empirically that, for Hurst coefficient H = 0.25, the constant of proportionality is μ = 1/3. We confirm this but find μ to vary with mode type and H. We find that due to lack of ergodicity, sample fBm variograms generated on finite windows exhibit directional dependence and differ sharply between realizations. Many realizations are required to obtain an average sample variogram resembling the theoretical power model, especially for persistent fields. We propose generating fBm on finite windows using truncated power variograms and provide guidance for doing so effectively
Scaling Effects on Finite-Domain Fractional Brownian Motion
No full textPower variograms of statistically isotropic or anisotropic fractal fields are weighted integrals of variograms representing statistically homogeneous fields (modes) having mutually uncorrelated increments. Large- and small-scale cutoffs were previ-ously assumed proportional to length scales of the sampling window and data support. We verify this assumption numerically for two-dimensional isotropic fractional Brownian motion (fBm). It was previously concluded semi-empirically that, for Hurst coefficient H = 0.25, the constant of proportionality is μ = 1/3. We confirm this but find μ to vary with mode type and H. We find that due to lack of ergodicity, sample fBm variograms generated on finite windows exhibit directional dependence and differ sharply between realizations. Many realizations are required to obtain an average sample variogram resembling the theoretical power model, especially for persistent fields. We propose generating fBm on finite windows using truncated power variograms and provide guidance for doing so effectively
Fashion Culture: Power In Fashion with Stefano Tonchi and Grazia d'Annunzio
No full textStefano Tonchi, global chief creative officer for L’Officiel Group, and Grazia d’Annunzio, former deputy director of Vogue Italia, discuss the power of military uniforms and their influence on high fashion. Tonchi is co-author of the book "Uniform: Order and Disorder.
Introduzione [a I cartolari del notaio Stefano di Corrado di Lavagna]
No full textSaggio introduttivo all’edizione dei frammenti dei protocolli del notaio Stefano di Corrado di Lavagna nel quale viene fatta l’analisi codicologica dei frammenti e si ricostruisce la biografia del notaio. Vengono inoltre esaminate la tipologia dei documenti, le tecniche redazionali del notaio e l’organizzazione burocratica della Chiesa genovese nella seconda metà del secolo XIII.
Introduction essay to the edition of the fragments of the protocols of the notary Stefano di Corrado of Lavagna in which the analysis of the codex fragments and reconstructs the biography of the notary is made by the author. She also examined the types of documents, the technical drafting of the notary and the bureaucratic organization of the Church of Genoa in the second half of the thirteenth century
From Lausanne to Luxembourg: the CJEU’s Seraing Judgment and the Boundaries of Sports Arbitration Under EU Law
No full textIn this expert analysis, Professor Stefano Bastianon dissects the CJEU’s landmark Seraing ruling (Case C-600/23), which reshapes the contours of sports arbitration under EU law. With particular focus on judicial review and EU public policy, the author explores how the Court balances the autonomy of arbitral mechanisms like CAS with the imperative of effective judicial protection — a judgment that could have far-reaching implications for the future of dispute resolution in sport
Laminar flow of a Harschel-Bulkley fluid in channels of finite width
No full textLaminar flow of a viscoplastic fluid in a shallow and wide channel is examined under the long-wave approximation. The fluid is described by the three-parameter Herschel-Bulkley constitutive equation. The complete set of equations governing the flow is presented, generalizing earlier results for a Bingham fluid. The paper then focuses on steady uniform flow: for different geometries of the channel (polynomials like triangular and parabolic, trapezoidal, and rectangular), the velocity distribution and the total discharge are derived analytically as functions of the fluid properties and of the channel cross-section. Results show the existence of dead zones close to bed and banks of the channel; discharges through any given cross-section are higher for dilatant than for pseudo-plastic fluids
- …
