Effect of Fluids

Fluids encompass a whole range of chemicals, both liquids and gases which can come into contact with rubber in various ways during service. Fluids can be absorbed and cause swelling of the rubber, or may extract soluble constituents of the compound, or may catalyse oxidation or have direct chemical effects. 

Time-swelling curves for three different materials in contact with test fluid (17) 

If chemical reactions take place, including the effect of temperature, the degradation will continue long after equilibrium absorption has been reached and volume change alone will not be a sufficient measure of the effect of the fluid. 

There are numerous instances where failure was the result of a rubber being used that was not sufficiently resistant to liquids encountered, in some cases because contact with the liquid in question had not been expected. A particular form of this problem is when the service liquid becomes contaminated, one case being where water stops swelled because oil leaked in during flooding. 

Rubbers with very poor resistance Diene mbbers (e.g., natural rubber, styrene butadiene rubber, nitrile mbber, budadiene mbber) 

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Effect of Fluid Viscosity and Inertia The dynamic effect of viscosity on a rotating liquid slurry as found in a sedimenting centrifuge is confined in veiy thin fluid layers, known as Ekman layers. These layers are adjacent to rotating surfaces which are perpendicular to the axis of rotation, such as bowl heads, flanges, and conveyor blades, etc. The thickness of the Ekman layer 6 is of the order... 

The effect of fluid inertia manifests during abrupt change in velocity of the fluid mass. It is quantified by the Rossby number ... 

The possible effects of fluid velocity on galvanic corrosion are sometimes overlooked. Fluid velocity can affect the apparent potential of metals in a given environment. Depending on the environment, a metal under the influence of relatively rapid flow may assume either a more noble or a more active character than that indicated by the galvanic series. Occasionally, this shift in potential may result in galvanic corrosion that would not occur under stagnant or low-flow conditions. 

Only a few popular and practical shell baffle arrangements exist, although special circumstances can and do require many unique baffling arrangements. The performance of the shell side of the exchanger depends upon the designer s understanding the effectiveness of fluid contact with the tubes as a direct result of the baffle pattern used. 

Weisman, J., Duncan, D Gibson, J. and Crawford, T. Inti. JL Multiphase Flow 5 (1979) 437-462. Effects of fluid properties and pipe diameter on two phase flow patterns in horizontal lines. 

The Chemkin package deals with problems that can be stated in terms of equation of state, thermodynamic properties, and chemical kinetics, but it does not consider the effects of fluid transport. Once fluid transport is introduced it is usually necessary to model diffusive fluxes of mass, momentum, and energy, which requires knowledge of transport coefficients such as viscosity, thermal conductivity, species diffusion coefficients, and thermal diffusion coefficients. Therefore, in a software package analogous to Chemkin, we provide the capabilities for evaluating these coefficients. ... 

The Engineering Effects of Fluids Flow on Freely Suspended Biological Macro-Materials and Macromolecules... 

The Engineering Effects of Fluid Flow on freely Suspended Biological Macro-Materials... 

Fig. 8. Sustained damage in Daucus carota suspensions, as a function of total energy expended, under laminar flow conditions in a Couette viscometer. Redrawn from Dunlop et al. (1994) Effect of fluid shear forces on plant cell suspensions. Chem Eng Sci 49 2263 - 2276, with permission of Elsevier Science...

In this volume not all stress types are treated. Various aspects have been reviewed recently by various authors e.g. The effects of oxygen on recombinant protein expression by Konz et al. [2]. The Mechanisms by which bacterial cells respond to pH was considered in a Symposium in 1999 [3] and solvent effects were reviewed by de Bont in the article Solvent-tolerant bacteria in biocatalysis [4]. Therefore, these aspects are not considered in this volume. Influence of fluid dynamical stresses on micro-organism, animal and plant cells are in center of interest in this volume. In chapter 2, H.-J. Henzler discusses the quantitative evaluation of fluid dynamical stresses in various type of reactors with different methods based on investigations performed on laboratory an pilot plant scales. S. S. Yim and A. Shamlou give a general review on the effects of fluid dynamical and mechanical stresses on micro-organisms and bio-polymers in chapter 3. G. Ketzmer describes the effects of shear stress on adherent cells in chapter 4. Finally, in chapter 5, P. Kieran considers the influence of stress on plant cells. 

J. L. Elbel, R. C. Navarrete, and B. D. Poe, Jr. Production effects of fluid loss in fracturing high-permeability formations. In Proceedings Volume, pages 201-211. SPE Europe Formation Damage Contr Conf (The Hague, Netherlands, 5/15-5/16), 1995. 

Z. Li. Effect of fluid viscoelasticity on isolated eddy transmission. J Univ Petrol, China, 15(5) 33-38, October 1991. 

The combined effect of fluids and insulin should decrease plasma glucose by approx 100-200 mg/dL per hour... 

Coulter, G.R. Hower, W. "The Effect of Fluid pH on Clays and Resulting Formation Permeability", Proc. Annu. Southwest Pet. Short Course, April 1975. 

McGowen, J.M. and McDaniel, B.W. "The Effects of Fluid Preconditioning and Test Cell Design on the Measurement of Dynamic Fluid Loss Data," SPE paper 18212, 1988 SPE Annual Technical Conference and Exhibition, Houston, October 2-5. 

Lee, W.S. "Study of the Effects of Fluid Rheology on Minifrac Analysis," SPE paper 16916, 1987 SPE Annual Technical Conference and Exhibition, Dallas, September 27-30. 

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