Search results for "Newton"

2015

We develop a model for the rheology of a three-phase suspension of bubbles and particles in a Newtonian liquid undergoing steady flow. We adopt an ‘effective-medium’ approach in which the bubbly liquid is treated as a continuous medium which suspends the particles. The resulting three-phase model combines separate two-phase models for bubble suspension rheology and particle suspension rheology, which are taken from the literature. The model is validated against new experimental data for three-phase suspensions of bubbles and spherical particles, collected in the low bubble capillary number regime. Good agreement is found across the experimental range of particle volume fraction ( 0 ≤ ϕ p ≲…

Shear-Thinning in Oligomer Melts—Molecular Origins and Applications

2021

We investigate the molecular origin of shear-thinning in melts of flexible, semiflexible and rigid oligomers with coarse-grained simulations of a sheared melt. Entanglements, alignment, stretching and tumbling modes or suppression of the latter all contribute to understanding how macroscopic flow properties emerge from the molecular level. In particular, we identify the rise and decline of entanglements with increasing chain stiffness as the major cause for the non-monotonic behaviour of the viscosity in equilibrium and at low shear rates, even for rather small oligomeric systems. At higher shear rates, chains align and disentangle, contributing to shear-thinning. By performing simulations …

Shear Thinning: Determination of Zero‐Shear Viscosities from Measurements in the Non‐Newtonian Region

2020

Some improvements in solving radial distributions networks through the backward/forward method

2005

In the electrical radial distribution networks analysis, the backward/forward method shows good features in terms of robustness, independence from load nature, small use of hardware resources and limited calculation time. In the present paper, some procedures to improve the b/f method with the aim of reducing the calculation time are presented. The adopted procedures regard the choice of the initial values of the nodes voltages and the way in which the convergence criterion is applied. The results of some tests carried out on some electrical test systems here reported have shown the efficiency of the proposed methodology in terms of calculation time reduction, especially when solving heavil…

The convergence of the perturbed Newton method and its application for ill-conditioned problems

2011

Abstract Iterative methods, such as Newton’s, behave poorly when solving ill-conditioned problems: they become slow (first order), and decrease their accuracy. In this paper we analyze deeply and widely the convergence of a modified Newton method, which we call perturbed Newton, in order to overcome the usual disadvantages Newton’s one presents. The basic point of this method is the dependence of a parameter affording a degree of freedom that introduces regularization. Choices for that parameter are proposed. The theoretical analysis will be illustrated through examples.

The Multiscale Stochastic Model of Fractional Hereditary Materials (FHM)

2013

Abstract In a recent paper the authors proposed a mechanical model corresponding, exactly, to fractional hereditary materials (FHM). Fractional derivation index 13 E [0,1/2] corresponds to a mechanical model composed by a column of massless newtonian fluid resting on a bed of independent linear springs. Fractional derivation index 13 E [1/2, 1], corresponds, instead, to a mechanical model constituted by massless, shear-type elastic column resting on a bed of linear independent dashpots. The real-order of derivation is related to the exponent of the power-law decay of mechanical characteristics. In this paper the authors aim to introduce a multiscale fractance description of FHM in presence …

Universal Gravitation and the (Un)Intelligibility of Natural Philosophy

2019

This article centers on Hume's position on the intelligibility of natural philosophy. To that end, the controversy surrounding universal gravitation shall be scrutinized. It is very well known that Hume sides with the Newtonian experimentalist approach rather than with the Leibnizian demand for intelligibility. However, what is not clear is Hume's overall position on the intelligibility of natural philosophy. It shall be argued that Hume declines Leibniz's principle of intelligibility. However, Hume does not eschew intelligibility altogether; his concept of causation itself stipulates mechanical intelligibility. peerReviewed

Parallel translations, Newton flows and Q-Wiener processes on the Wasserstein space

2022

- We extend the definition of Lott’s Levi-Civita connection to the Wasserstein space of probability measures having density and divergence. We give an extension of a vector field defined along an absolutely curve onto the whole space so that parallel translations can be introduced as done in differential geometry. In the case of torus, we prove the well-posedness of Lott’s equation for parallel translations.- We prove the well-posedness of the Newton flow equation on the Wasserstein space and show the connections between the relaxed Newton flow equation and the Keller-Segel equation.- We establish an intrinsic formalism for Itô stochastic calculus on the Wasserstein space throughout three k…

Learning to synthesize contradictions: An Austrian Approach to Bridging Time Concepts in the Theory of the Firm

2008

By analysing the implcit assumptions regarding time underlying the theories of the resource based firm, and analysing the views they portray, we propose a theoretical framework which allows to bridge balue creation and value appropriation issues in strategy studies.

Remark on a nonlocal isoperimetric problem

2017

Abstract We consider isoperimetric problem with a nonlocal repulsive term given by the Newtonian potential. We prove that regular critical sets of the functional are analytic. This optimal regularity holds also for critical sets of the Ohta–Kawasaki functional. We also prove that when the strength of the nonlocal part is small the ball is the only possible stable critical set.