Navier-Stokes Equation and Computational Scheme for Non-Newtonian Debris Flow

This paper proposes a computational approach to debris flow model. In recent years, the theoretical activity on the classical Herschel-Bulkley model (1926) has been very intense, but it was in the early 80s that the opportunity to explore the computational model has enabled considerable progress in identifying the subclasses of applicability of different sets of boundary conditions and their approximations. Here we investigate analytically the problem of the simulation of uniform motion for heterogeneous debris flow laterally confined taking into account mainly the geological data and methodological suggestions derived from simulation with cellular automata and grid systems, in order to propose a computational scheme able to operate a compromise between "global" predictive capacities and computing effort

A Machian Request for the Equivalence Principle in Extended Gravity and non-geodesic motion

Starting from the origin of Einstein general relativity (GR) the request of Mach on the theory's structure has been the core of the foundational debate. That problem is strictly connected with the nature of the mass-energy equivalence. It is well known that this is exactly the key point that Einstein used to realize a metric theory of gravitation having an unequalled beauty and elegance. On the other hand, the current requirements of particle physics and the open questions within extended gravity theories request a better understanding of Equivalence Principle (EP). The MOND theory by Milgrom proposes a modification of Newtonian dynamics and we consider a direct coupling between the Ricci curvature scalar and the matter Lagrangian showing that a non geodesic ratio m_{i}/m_{g} can be fixed and that Milgrom acceleration is retrieved at low energies.Comment: 11 pages, accepted for publication in Gravitation and Cosmology, to appear in in vol. 22, issue 1 (2016) of the journa

On the general relativistic framework of the Sagnac effect

The Sagnac effect is usually considered as being a relativistic effect produced in an interferometer when the device is rotating. General relativistic explanations are known and already widely explained in many papers. Such general relativistic approaches are founded on Einstein's equivalence principle (EEP), which states the equivalence between the gravitational "force" and the pseudo-force experienced by an observer in a non-inertial frame of reference, included a rotating observer. Typically, the authors consider the so-called Langevin-Landau-Lifschitz metric and the path of light is determined by null geodesics. This approach partially hides the physical meaning of the effect. It seems indeed that the light speed varies by c\pm\omega r in one or the other direction around the disk. In this paper, a slightly different general relativistic approach will be used. The different "gravitational field" acting on the beam splitter and on the two rays of light is analyzed. This different approach permits a better understanding of the physical meaning of the Sagnac effect.Comment: 9 pages, to appear in the European Physical Journal

Lie Group of Spacetime

A brief review is presented of de Sitter-Fantappiè relativity, and we propose some cosmological reflections suggested by this theory. Compared to the original works, some deductions have been very simplified, and only the physical meaning of the equations has been analyzed

Metodi innovativi di Information Fusion per la crittografia

2011 - 2012Nel presente lavoro viene mostrato un sistema per realizzare un codice crittografico, che sia utilizzabile per garantire un alto livello di segretezza usando tecniche di Information Fusion (IF). Nel dettaglio, si è deciso di fondere due codici; uno generato tramite un algoritmo di crittografia a chiave pubblica e uno creato mediante l’utilizzo di formule matematiche innovative basate sui frattali. La tecnica di Information Fusion utilizzata è stata presentata in precedenza con un differente utilizzo ed opportune modifiche. Infatti, nel precedente lavoro, veniva creato un codice di accesso identificativo, mentre, in questo, viene generata una chiave crittografica fortemente casuale da utilizzare in ambito di cifratura. La scelta di utilizzare i frattali per generare una sequenza numerica da fondere con codici utilizzati nella cifratura a chiave pubblica è vincolata alla caratteristica randomica di tali strutture. Questo porta all’idea di utilizzare queste caratteristiche per applicazioni crittografiche quali One-Time-Pad. La tecnica di fusione modificata è denominato F&NIF (Fractal & Numerical Information Fusion). [a cura dell'autore]In this paper we want to show a system to realize a cryptography code. This system must ensure a high level of security using Information Fusion (IF) technique. In particular, we have decided to merge two codes generated by an algorithm of Public-key Cryptography and by fractals relations respectively. This IF method has been presented with a different use. In fact, in the previous paper, was created an identification access key but now we want to generate a very random Cryptography key to be used for encryption. The choice of using fractals to generate numbers to be fused with codes of Public-Key Cryptography, is due to the randomness of these structures. The idea is to use these features for cryptographic applications such as One-Time-Pad. The modified fusion technique is called F&NIF (Fractal & Numerical Information Fusion). [edited by author]XI n.s

Generalized potential for apparent forces: the Coriolis effect

It is well known, from Newtonian physics, that apparent forces appear when the motion of masses is described by using a non-inertial frame of reference. The generalized potential of such forces is rigorously analyzed focusing on their mathematical aspects.Comment: 8 pages, accepted for publication in Eur. J. Phy

Rotation induced in a coil moving in an electric field

The integral form of the fourth Maxwell's equation is often written in two different ways: in the first, the partial derivative of Electric field appears, while the second contains a time derivative of electric flux integral. It would be useful, from a didactic point of view, to discriminate between the two different interpretations. In this paper, starting from a previous work about Faraday's law, we analyze the derivative of the flux of the electric field and we shed light on the right way to write the Maxwell equations. We introduce a "magnetomotive force" and we find, from the corresponding generalization of the second Laplace's law, the effect of a rotation induced in a coil embedded in an electric field