Search results for "Principle"
showing 10 items of 1023 documents
Changes in Transport and Non Transport Costs: Local vs. Global Impacts in a Spatial Network
2007
We develop a multi-country Dixit-Stiglitz trade model and analyze how industry location and welfare respond to changes in: (i) transport frictions (e.g., infrastructure, transportation technology); and (ii) non-transport frictions (e.g., tariffs, standards and regulations). We show that changes in non-transport frictions, which are usually origin-destination specific, do not allow for any clear prediction as to changes in industry location and welfare; whereas changes in transport frictions, which are usually not origin-destination specific, may allow for such predictions. In particular, we show that reductions in transport frictions occurring at links around which the spatial network is lo…
Prices and Pareto optima
2006
We provide necessary conditions for Pareto optimum in economies where tastes or technologies may be nonconvex, nonsmooth, and affected by externalities. Firms can pursue own objectives, much like the consumers. Infinite-dimensional commodity spaces are accommodated. Public goods and material balances are accounted for as special instances of linear restrictions.
Active nonlinear microrheology in a glass-forming Yukawa fluid.
2012
A molecular dynamics computer simulation of a glass-forming Yukawa mixture is used to study the anisotropic dynamics of a single particle pulled by a constant force. Beyond linear response, a scaling regime is found where a force-temperature superposition principle of a Peclet number holds. In the latter regime, the diffusion dynamics perpendicular to the force can be mapped on the equilibrium dynamics in terms of an effective temperature, whereas parallel to the force a superdiffusive behavior is seen in the long-time limit. This behavior is associated with a hopping motion from cage to cage and can be qualitatively understood by a simple trap model.
Nonequilibrium depletion interactions in active microrheology.
2017
Entropic depletion forces arise between mesoscopic bodies that are immersed in a suspension of macromolecules, such as colloid-polymer mixtures. Here we consider the case of a driven colloidal probe in the presence of another, passive colloidal particle, both solvated in an ideal bath of small spherical particles. We calculate the nonequilibrium forces mediated by the depletants on the two colloidal particles within a dynamical superposition approximation (DSA) scheme. In order to assess the quality of this approximation, and to obtain the colloidal microstructure around the driven probe, we corroborate our theoretical results with Brownian dynamics simulations.
Positive solutions for parametric singular Dirichlet (p,q)-equations
2020
We consider a nonlinear elliptic Dirichlet problem driven by the (p,q)-Laplacian and a reaction consisting of a parametric singular term plus a Caratheodory perturbation f(z,x) which is (p-1)-linear as x goes to + infinity. First we prove a bifurcation-type theorem describing in an exact way the changes in the set of positive solutions as the parameter lambda>0 moves. Subsequently, we focus on the solution multifunction and prove its continuity properties. Finally we prove the existence of a smallest (minimal) solution u*_lambda and investigate the monotonicity and continuity properties of the map lambda --> u*_lambda.
Variational Formulations for Coupled BE/FE Methods in Elastostatics
1994
Ein gekoppeltes BEM/FEM-Problem aus der Elastostatik, ein typisches Substrukturproblem, wird im Rahmen der symmetrisch-definiten BEM behandelt. Es werden vier verschiedene Variationsformulierungen vorgestellt, in deren jeder die Transmissionsbedingungen gegenuber der Trennflache zwischen FE-Unterregion und BE-Unterregion die Rolle naturlicher Randbedingungen spielen. Zwei der oben erwahnten Formulierungen sind Stationaritatsprinzipien in gemischter Form, die anderen beiden sind Sattelpunkt-Prinzipien, d. h. Kombinationen des Rand-min-max-Prinzips entweder mit dem Prinzip der minimalen Gesamtpotentialenergie oder mit dem Prinzip der minimalen Gesamtkomplementaritatsenergie. Jedes der oben an…
On the moving load problem in Euler–Bernoulli uniform beams with viscoelastic supports and joints
2016
This paper concerns the vibration response under moving loads of Euler–Bernoulli uniform beams with translational supports and rotational joints, featuring Kelvin–Voigt viscoelastic behaviour. Using the theory of generalized functions to handle the discontinuities of the response variables at the support/joint locations, exact beam modes are obtained from a characteristic equation built as determinant of a (Formula presented.) matrix, for any number of supports/joints. Based on pertinent orthogonality conditions for the deflection modes, the response under moving loads is built in the time domain by modal superposition. Remarkably, all response variables are built in a closed analytical for…
A TDDFT-based Study on the Proton-DNA Collision
2019
The interaction of heavy charged particles with DNA is of interest for several areas, from hadrontherapy to aero-space industry. In this paper, a TD-DFT study on the interaction of a 4 keV proton with an isolated DNA base pair was carried out. Ehrenfest dynamics was used to study the evolution of the system during and after the proton impact up to about 193 fs. This time was long enough to observe the dissociation of the target, which occurs between 80-100 fs. The effect of base pair linking to the DNA double helix was emulated by fixing the four O3' atoms responsible for the attachment. The base pair tends to dissociate into its main components, namely the phosphate groups, sugars and nitr…
Multiple Decay Mechanisms and 2D-UV Spectroscopic Fingerprints of Singlet Excited Solvated Adenine-Uracil Monophosphate
2016
The decay channels of singlet excited adenine uracil monophosphate (ApU) in water are studied with CASPT2//CASSCF:MM potential energy calculations and simulation of the 2D-UV spectroscopic fingerprints with the aim of elucidating the role of the different electronic states of the stacked conformer in the excited state dynamics. The adenine 1La state can decay without a barrier to a conical intersection with the ground state. In contrast, the adenine 1Lb and uracil S(U) states have minima that are separated from the intersections by sizeable barriers. Depending on the backbone conformation, the CT state can undergo inter-base hydrogen transfer and decay to the ground state through a conical …
Predicting Skin Permeability by Means of Computational Approaches: Reliability and Caveats in Pharmaceutical Studies
2019
The skin is the main barrier between the internal body environment and the external one. The characteristics of this barrier and its properties are able to modify and affect drug delivery and chemical toxicity parameters. Therefore, it is not surprising that permeability of many different compounds has been measured through several in vitro and in vivo techniques. Moreover, many different in silico approaches have been used to identify the correlation between the structure of the permeants and their permeability, to reproduce the skin behavior, and to predict the ability of specific chemicals to permeate this barrier. A significant number of issues, like interlaboratory variability, experim…