Search results for "VISCOSITY"
showing 10 items of 542 documents
A compliant visco-plastic particle contact model based on differential variational inequalities
2013
This work describes an approach to simulate contacts between threedimensional shapes with compliance and damping using the framework of the differential variational inequality theory. Within the context of nonsmooth dynamics, we introduce an extension to the classical set-valued model for frictional contacts between rigid bodies, allowing contacts to experience local compliance, viscosity, and plasticization. Different types of yield surfaces can be defined for various types of contact, a versatile approach that contains the classic dry Coulomb friction as a special case. The resulting problem is a differential variational inequality that can be solved, at each integration time step, as a v…
Kramers potential study of the Rouse-like dynamics of short alkane chains.
1999
In this work we present a Kramers potential study of the orientational dynamics and shear viscosity of short chain alkanes. In this approach the determination of the orientational relaxation time is reduced to the calculation of static moments of single chain conformations. We study a chemically realistic alkane model that asymptotically produces Gaussian chain conformations by means of a Monte Carlo simulation. Our results are applicable to single chain descriptions of polymer melt dynamics and to the intrinsic viscosity of molecules in a Theta solvent. When we map the unknown time unit of our relaxation time result for one particular chain length and temperature to the value obtained for …
Treatment of Herráez equation correlating viscosity in binary liquid mixtures exhibiting strictly monotonous distribution
2013
Recently, Herraez et al. proposed a new correlation equation, which introduces a correcting polynomial as an exponential-acting upon the molar fraction of one of mixture components. This equation is found to be widely applicable with more reasonable accuracy in systems exhibiting monotonous distribution than those presenting an extremum. In previous works, we have found that the first adjustable parameter of this equation is a universal exponent (0.5 or 1) for dioxane–water and isobutyric acid–water mixtures characterising the presence of solute–solute or solute–solvent interaction at very high dilution. In this work, we have tested this equation in 48 systems, and we have noted that severa…
Solid–Liquid Suspensions in Top-Covered Unbaffled Vessels: Influence of Particle Size, Liquid Viscosity, Impeller Size, and Clearance
2014
Particle suspension in liquids is a unit operation commonly encountered in the process industry. Although it is usually carried out in baffled stirred tanks, there are some specific applications where the presence of baffles may be undesirable. In the present work solid-liquid suspensions are investigated in a radially stirred unbaffled tank provided with a top cover. The minimum impeller speed at which all solid particles get suspended (Njs) and the relevant power requirements (Pjs) are assessed. The dependence of these two parameters on physical properties (liquid viscosity, particle concentration, and size) and system geometrical configurations (impeller diameter and clearance) is invest…
Low-cost viscometer based on energy dissipation in viscous liquids
2001
We describe a new type of low-cost easy-to-use viscometer based on the temperature elevation in a liquid under shear flow. After calibration, this instrument can be used to measure the apparent steady state viscosity for both Newtonian and non-Newtonian liquids with no yield stress. We compute the rise in temperature due to viscous dissipation in a Couette cell and compare it to experimental results for different fluids. We show that the variation of the temperature with shear rate can be used to characterize the rheological behaviour of viscous fluids and to evaluate their viscosity in a large domain, from typically a few cP up to more than 10 P, with an accuracy of about ±5%. In contrast …
Evaluation de la déstructuration orale de protéagineux extrudés
2018
La formulation de snacks expansés sans gluten et riches en protéines, fabriqués entièrement à partir deprotéagineux, est un moyen intéressant pour diversifier l’offre d’aliments à base de protéagineux.L'extrusion est un procédé souple et adapté pour fabriquer de tels aliments. Lors du traitementthermomécanique, la dépolymérisation de l’amidon, et donc sa solubilité, augmentent, alors que la solubilité des protéines diminue à cause des phénomènes d’agrégation. En conséquence, l'extrusion produit des mousses solides avec une grande variété de textures et de morphologies du matériel constitutif, autant de caractéristiques qui vont affecter les performances de mastication et l’acceptabilité du …
Using cross-modal interactions to counterbalance salt reduction in solid foods
2011
International audience; We investigated odour-induced saltiness enhancement (OISE) in a solid model cheese with the aim of evaluating the influence of cross-modal interactions (odour-texture-taste) on saltiness perception and assessing the efficacy of using OISE to counterbalance salt reduction. Four model cheeses, varying in texture, were flavoured with three commercial tasteless aromas (comte cheese, sardine and carrot) differently associated with salty and cheesy food products. Twenty-seven consumers evaluated taste intensity, aroma intensity and its congruence with the product flavour, and the overall pleasantness of 12 flavoured and four unflavoured samples. The comparison of the perce…
Effects of ultrasound and high pressure on physicochemical properties and HMF formation in Turkish honey types
2018
Abstract In industrial production, thermal processing of honey at 50 °C commonly induces liquefaction, i.e. it reduces the crystal count and viscosity and delays any subsequent crystallization. Unfortunately, thermal treatment can generate toxic 5-hydroxymethylfurfural (HMF), thereby resulting in quality reduction. Considering this, the present work aims at evaluating the influence of (two) processing technologies as alternatives to thermal processing of honey, namely high hydrostatic pressure (HHP; P = 220–330 MPa, T = 50/60 °C, t = 23/106 min), and ultrasound processing (US; at 24 kHz). The quality parameters evaluated for honey included liquefaction time, HMF content, diastase number, co…