Search results for "quantity"
showing 10 items of 151 documents
A lumped model for a seismic source
1993
A lumped mechanical model is proposed and solved. This model is dynamically equivalent, in the mean field approximation, to a faulted lithosphere. The transition from the continuous system (modelled according to W. H. Prescott and A. Nur) to the lumped one, has been made by preserving all the relevant features exhibited by the continuous system. In particular the coupling between different components of the stress and strain tensors is suitably taken into account. The dynamics of the lumped system depends on six control parameters fixed by the physical properties of the continuous system. Three of the control parameters are dimensionless and describe: the seismic wave quality factor of the…
Maxwell Theory as a Classical FieldTheory
2012
Hamilton’s variational principle and the Lagrangian mechanics that rests on it are exceedingly successful in their application to mechanical systems with a finite number of degrees of freedom. Hamilton’s principle characterizes the physically realizable orbits, among the set of all possible orbits, as being the critical elements of the action integral. The Lagrangian function, although not an observable on its own, is not only useful in deriving the equations of motion but is also an important tool for identifying symmetries of the theory and constructing the corresponding conserved quantities, via Noether’s theorem.
Entropic approach to estimate the mean flow velocity: experimental investigation in laboratory flumes
2015
The paper deals with the linear entropic relationship between the maximum velocity, u max , and the mean flow velocity, u m , through a dimensionless parameter Φ(M), in open-channel flow. The analysis is conducted with the aid of experimental data collected in straight laboratory flumes under different bed and side-walls roughness conditions. In particular, rough/vegetated beds and smooth/rough side-walls conditions have been investigated. The results show that, in the investigated conditions (with exception of low-submergence vegetated bed—h/k v < 2), Φ(M) can be assumed equal to a value that is very close to that found in natural channels. This demonstrates that Φ(M) is able to implicitl…
Relationship between UVB and broadband solar radiation in Spain
2014
The daily values of UVB irradiation (290–315 nm), IUVB, and the broadband total irradiation (300–2800 nm), IT, measured on a horizontal plane have been correlated for the period 2000–2008 at 16 measurement sites in Spain. The results have been compared with the daily experimental values registered at the same sites during the period 2009–2011. The coefficients of determination R2 obtained by applying a linear regression are higher than 0.88 for all sites and increase to 0.94 when using a quadratic regression. When all data are considered together, the values of R2 are 0.91 and 0.97 for the linear and quadratic regressions, respectively. Three different clearness indices, which are dimension…
Critical study of the quantity theory of money in the history of prices crisis
2014
The Quantity Theory of money which always links the increase in the high-Powered money supply and the general rise in prices is one of the oldest concepts in economics. After to have been the subject of many controversies at different times, it seems nowadays to hold less attention from the economists because the dispute is dissipated in a kind of religious choice to believe or not to believe to quantity theory. This theory officially influences the monetary policy of most of central banks in the world that bind conventional measures to control the money supply to curb inflation process. In many orthodox economics’ textbooks, the quantity theory is still deployed in perpetuum to explain the…
Measurement of the π0, η, η′ Transition Form Factors at BABAR
2013
Abstract Measurements of the transition form factors of the pseudoscalar mesons π 0 , η, η ′ have been carried out by the BABAR collaboration at the SLAC B-factory PEP-II. The form factors F ( Q 2 ) were measured in two-photon processes covering the kinematic range 4 GeV 2 Q 2 40 GeV 2 . For the π 0 form factor, results are significantly higher than predicted by Brodsky and Lepage assuming an asymptotic distribution amplitude. Data also suggest that the asymptotic regime of QCD is reached only at relatively high Q 2 . We also report on measurements of the η and η ′ transition form factors, which happen to feature a significantly different Q 2 behaviour than the one of the neutral pion.
Inverse square root level-crossing quantum two-state model
2020
We introduce a new unconditionally solvable level-crossing two-state model given by a constant-amplitude optical field configuration for which the detuning is an inverse-square-root function of time. This is a member of one of the five families of bi-confluent Heun models. We prove that this is the only non-classical exactly solvable field configuration among the bi-confluent Heun classes, solvable in terms of finite sums of the Hermite functions. The general solution of the two-state problem for this model is written in terms of four Hermite functions of a shifted and scaled argument (each of the two fundamental solutions presents an irreducible combination of two Hermite functions). We pr…
Kinetics of phase separation in polymer blends for deep quenches
1986
Electro microscopy was used to study the phase separation kinetics of a polystyrene/polyvinylmethylether system subjected to a critical deep quench. The size of the phase-separated domains was found to increase linearly with time, implying that hydrodynamic effects control the rate of growth of the domains in the time scale and temperature range under consideration. From these measurements the growth velocity and approximate diffusion constants can be determined for three different temperatures. Comparison of these results with those obtained by light scattering on other systems and with theoretical predictions is possible by replotting in dimensionless units.
Modelling glow curves of thermoluminescent radiometric devices
2017
Thermoluminescent (TLD) radiation dosimeters enjoy wide usage due to low cost and simplicity of use. They however require complex device modelling in order to extract the measured dose. A new glow peak model and fit method are presented, that offer a more robust fit to the glow-curves and allows operators to enter visually inspectable parameters (rather than physical quantities difficult to estimate from the visual inspection of the glow curves themselves). Fits performed on the GLOCANIN-challenge's RefGlow-002 and RefGlow-009 [2] are presented, highlighting the good performance of the GEMINI C++ code written.
Capturing gypsum rillenkarren morphometry by a 3D-photo reconstruction (3D-PR) technique
2020
Abstract Rillenkarren are small scale, straight, narrow solution channels that head at the crest of a bare rock slope and are extinguished downslope. In this paper the applicability of 3D-photo reconstruction technique of the rock surface is proposed for capturing the rillenkarren morphometry on gypsum. At first, the measurements are used to assess a relationship between the width/depth ratio and the depth of the rillenkarren. The exponent of this power relationship resulted different from the theoretical value - 0.5, confirming that the cross-section profiles of a rillenkarren can have a shape different from parabolic. The analysis developed for the cross-section area, the perimeter and th…