Search results for "laws"
showing 10 items of 147 documents
Effective diffusion coefficient and diffusion-controlled reactions in insulating solids with defects
1995
Abstract The expressions for effective diffusion coefficient are obtained in the mean field approximation for two-phase system for spatial dimensions of 1, 2 and 3. The existence of potential barrier for diffusion on the phase boundary was taken into account via the boundary conditions. Obtained formulae could be applied in the theory of diffusion-controlled reactions and for interpreting the experimental data on defect diffusion in two-phase media.
Oxygen Diffusion Constants D and K of Tumor Tissue (DS-Carcinosarcoma) and Their Temperature Dependence
1978
To understand more thoroughly the tumor O2 supply conditions, knowledge of O2 diffusivity in tumor tissue is required. Since exact measurements of the O2 diffusion constants of tumor tissue have not been carried out to date, previous investigations of tumor O2 supply had to employ estimated values (6 – 8, 10). The results of these studies are in part contradictory.
The taint of torture and the brazilian legal system
2019
In Brazil, the practice of torture intertwines deeply with its own history. The literature on the subject has had a greater intensification on its registers during the Dictatorial Regime (1964 to 1985). In spite of the Brazilian Constitution of 1988, Brazil only makes efforts to investigate the crimes of torture of this period to comply with the provisions of the United Nations in 2011. Within this scenario, the NationalTruth Commission (Law 12.528, of November 2011) was created with the purpose of clarifying the facts and circumstances of cases concerning human rights violations, as well as the Law on Access to Information (Law 12.527 of November 2011), which have regulated the constitutio…
Articolo 56
2018
Questo contributo offre un breve commento all'articolo 56 della Costituzione italiana, avente ad oggetto la Camera dei Deputati, la sua natura elettiva, i principi e le regole per la sua composizione. Viene preso in esame il testo costituzionale del 1948 ed il significato delle elezioni democratiche; il rapporto fra eletti ed elettori e le revisioni costituzionali del 1963 e del 2001; il problema della forza prescrittiva dell'articolo 56: l'esigenza di adattamento della Costituzione all'evoluzione del quadro politico; l'articolo 56 della Costituzione come limite per il legislatore in materia elettorale: il ruolo della magistratura e della Corte costituzionale.
Constraints on the sources of post-collisional K-rich magmatism: The roles of continental clastic sediments and terrigenous blueschists
2017
Abstract The possible role of continental sediments in the generation of potassium-enriched lavas of the Alpine-Himalayan belt depends on their melting behaviour either during subduction or during post-collisional relaxation. Although usually classed as orogenic lavas, these volcanic rocks may result from re-melting of newly formed mantle lithosphere 30–40 million years after collision ends, and can thus be considered as the first stage of intraplate volcanism. The potassic component in these volcanics is characterized by a high Th/La signature for which there are two competing explanations: melting of subducted continental clastic sediments, and the involvement of lawsonite blueschists in …
The relaxation dynamics of a viscous silica melt: II The intermediate scattering functions
2001
We use molecular dynamics computer simulations to study the relaxation dynamics of a viscous melt of silica. The coherent and incoherent intermediate scattering functions, F_d(q,t) and F_s(q,t), show a crossover from a nearly exponential decay at high temperatures to a two-step relaxation at low temperatures. Close to the critical temperature of mode-coupling theory (MCT) the correlators obey in the alpha-regime the time temperature superposition principle (TTSP) and show a weak stretching. We determine the wave-vector dependence of the stretching parameter and find that for F_d(q,t) it shows oscillations which are in phase with the static structure factor. The temperature dependence of the…
Static and dynamic properties of a viscous silica melt
1999
We present the results of a large scale molecular dynamics computer simulation in which we investigated the static and dynamic properties of a silica melt in the temperature range in which the viscosity of the system changes from ${O(10}^{\ensuremath{-}2})$ P to ${O(10}^{2})$ P. We show that even at temperatures as high as 4000 K the structure of this system is very similar to the random tetrahedral network found in silica at lower temperatures. The temperature dependence of the concentration of the defects in this network shows an Arrhenius law. From the partial structure factors we calculate the neutron scattering function and find that it agrees very well with experimental neutron scatte…
Effective temperature and scaling laws of polarized quantum vortex bundles
2011
Abstract An effective non-equilibrium temperature is defined for (locally) polarized and dense turbulent superfluid vortex bundles, related to the average energy of the excitations (Kelvin waves) of vortex lines. In the quadratic approximation of the excitation energy in terms of the wave amplitude A, a previously known scaling relation between amplitude and wavelength k of Kelvin waves in polarized bundles, namely A ∝ k − 1 / 2 , follows from the homogeneity of the effective temperature. This result is analogous to that of the well-known equipartition result in equilibrium systems.
Testing Mode-Coupling Theory for a Supercooled Binary Lennard-Jones Mixture II: Intermediate Scattering Function and Dynamic Susceptibility
1995
We have performed a molecular dynamics computer simulation of a supercooled binary Lennard-Jones system in order to compare the dynamical behavior of this system with the predictions of the idealized version of mode-coupling theory (MCT). By scaling the time $t$ by the temperature dependent $\alpha$-relaxation time $\tau(T)$, we find that in the $\alpha$-relaxation regime $F(q,t)$ and $F_s(q,t)$, the coherent and incoherent intermediate scattering functions, for different temperatures each follows a $q$-dependent master curve as a function of scaled time. We show that during the early part of the $\alpha$-relaxation, which is equivalent to the late part of the $\beta$-relaxation, these mast…
Dynamics of the rotational degrees of freedom in a supercooled liquid of diatomic molecules
1997
Using molecular dynamics computer simulations, we investigate the dynamics of the rotational degrees of freedom in a supercooled system composed of rigid, diatomic molecules. The interaction between the molecules is given by the sum of interaction-site potentials of the Lennard-Jones type. In agreement with mode-coupling theory (MCT), we find that the relaxation times of the orientational time correlation functions C_1^(s), C_2^(s) and C_1 show at low temperatures a power-law with the same critical temperature T_c, and which is also identical to the critical temperature for the translational degrees of freedom. In contrast to MCT we find, however, that for these correlators the time-tempera…