Search results for "Potential"
showing 10 items of 3348 documents
A unifying variational framework for stress gradient and strain gradient elasticity theories
2015
Abstract Stress gradient elasticity and strain gradient elasticity do constitute distinct continuum theories exhibiting mutual complementary features. This is probed by a few variational principles herein presented and discussed, which include: i) For stress gradient elasticity, a (novel) principle of minimum complementary energy and an (improved-form) principle of stationarity of the Hellinger–Reissner type; ii) For strain gradient elasticity, a (known) principle of minimum total potential energy and a (novel) principle of stationarity of the Hu–Washizu type. Additionally, the higher order boundary conditions for stress gradient elasticity, previously derived by the author (Polizzotto, Int…
GHB related acids are useful in routine casework of suspected GHB intoxication cases
2021
Abstract GHB related acids (3,4-dihydroxy butyric acid, 2,4-dihydroxy butyric acid and glycolic acid) are produced through oxidative GHB metabolism. These analytes could be potential biomarkers to ensure the diagnosis of a GHB intoxication and even prolong the detection window. Within this study, forensic routine cases were measured to consider the potential of additional gas chromatographic mass spectrometric analysis on these acids. 17 GHB positive real cases (10 serum samples and 7 urine samples) and 40 cases with suspicion of drugging in DFC cases and negative GHB results (21 serum samples and 19 urine samples) were evaluated. Increased GHB related acid concentrations were detected in a…
Shot-clay MX-80 bentonite: An assessment of the hydro-mechanical behaviour
2014
This study presents the results of an experimental study conducted to characterise the hydro-mechanical behaviour of shot-clay MX-80 bentonite. In the shot-clay process, granular bentonite was mixed continuously with water and shot on the walls of a tunnel section at the Grimsel Underground Research Laboratory (URL), in Switzerland. The shot-clay was placed to create a layer of bentonite in direct contact with the host rock to avoid preferential water and/or gas flow along the tunnel wall. Samples for an experimental programme were collected during the shooting. The index properties, microstructural features, swelling potential and water retention properties of the shot-clay were analysed. …
Nonlinear current-voltage characteristics due to quantum tunneling of phase slips in superconducting Nb nanowire networks
2013
We report on the transport properties of an array of N about 30 interconnected Nb nanowires, grown by sputtering on robust porous Si substrates. The analyzed system exhibits a broad resistive transition in zero magnetic field, H, and highly nonlinear V(I) characteristics as a function of H which can be both consistently described by quantum tunneling of phase slips.
The explicative power of the vector potential for superconductivity: a path for high school
2014
In the classroom practice the notion of the magnetic vector potential is never introduced, both because it is not contained in secondary school textbooks and because teachers usually associate this concept with complex topics they dealt with in their university courses. In our experience instead, we have found that the introduction of the vector potential can be of great help in students’ understanding of electromagnetism and modern physics topics. In this paper we will show how the use of the vector potential allows a phenomenological and consistent explanation of superconductivity at a level suitable for high school students. We will deal with the two main aspects of superconductivity: th…
Observable Variables in Thermoelectric Phenomena
2002
New transport equations for the thermoelectric phenomena have been deduced. All of the variables in this formulation are observable quantities. The limitations of the usual formulations, which work with nonobservable quantities, have been overcome. The electric potential can be measured by using auxiliary probes which connect the electronic conductor to a potentiometer. This observable electric potential depends on the nature of the probes but not on the room temperature where the potentiometer is placed. Also, we emphasize that absolute values for the thermoelectric power are in contradiction with the thermodynamic limitation of measuring electric potential differences in these systems. Th…
Vector Potential at High School: A Way to Introduce Superconductivity and to Review Electromagnetism
2014
Superconductivity is a rich and complex topic that generates great interest and curiosity in high school students. Most of the presentations of superconductivity give a great importance to magnetism. But typically in these presentations the physical role is played by the magnetic field B while the magnetic vector potential A is never mentioned. Moreover the explanation of the quantum phenomena at the base of the superconductivity are often not enough developed and generally given only at a popular level. We think that the key point for a meaningful presentation at high school is the vector potential. In this paper we present a teaching path on the vector potential and a pilot experimentatio…
Structure and pair correlations of a simple coarse grained model for supercritical carbon dioxide
2009
A recently introduced coarse-grained pair potential for carbon dioxide molecules is used to compute structural properties in the supercritical region near the critical point, applying Monte Carlo simulations. In this model, molecules are described as point particles, interacting with Lennard-Jones (LJ) forces and a (isotropically averaged) quadrupole–quadrupole potential, the LJ parameters being chosen such that gratifying agreement with the experimental phase diagram near the critical point is obtained. It is shown that the model gives also a reasonable account of the pair correlation function, although in the nearest neighbour shell some systematic discrepancies between the model predicti…
Literatur – grundsätzlich mehrsprachig!? Das politische Potenzial literarischer Mehrsprachigkeit heute, am Beispiel von Barbi Marković’ Superheldinnen
2021
Literature – Multilingual on Principle?! The Political Potential of Literary Multilingualism Today, using the Example of Barbi Marković’s Superheldinnen. Research on literary multilingualism is increasingly based on the assumption that literature per se is multilingual. This is true for concepts such as Mikhail Bakhtin’s ‘polyphony’, in which multilingualism occurs in the form of social, regional and historical variants within one major language. Similarly, it applies to Rainier Grutman’s concept of hétérolinguisme, which expands Bakhtin’s notion and includes actual language changes. Recently, Till Dembeck has even called for a philology of multilingualism that would accommodate literary mu…
High-pressure Raman study of theN2stretching vibration in argon-nitrogen mixtures at room temperature
1996
We present room-temperature Raman investigations of the nitrogen molecule stretching vibration in ${\mathrm{Ar}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$(${\mathrm{N}}_{2}$${)}_{\mathit{x}}$ from x=1 to x=0.59 in the pressure range 1\ensuremath{\le}p\ensuremath{\le}31 GPa. Ar substitution leads to an inhomogeneous broadening of the vibrational signal. The \ensuremath{\beta}-\ensuremath{\delta} phase transition of pure ${\mathrm{N}}_{2}$ is shifted to higher pressures for x=0.75. The substituted Ar atoms preferentially occupy the 2a sites of the cubic elementary cell of the orientationally disordered \ensuremath{\delta} phase. This interpretation of the experimental data is supported by our mod…