Package porosity

Generally, as permeability decreases, increasing pressure drops are required across a package in order to maintain a desired flow rate. The density differences in a yam package result in permeability variations, which directly affect flow behaviour within the package. The correlation between package density and permeability was discussed by Denton, who addressed this correlation for cotton yam packages. Porosity-permeability correlations for other types of fibrous porous media are also available from the literature. " Consideration of these works is beyond the scope of the material presented here. 

In Fig. 6.34, the sohd and dashed lines represent the concentration of (fye on fibres at the exit line of the package at time t, when the porosity of the package is 0.5 and 0.3, respectively. Simulation results reveal that the package porosity strongly affects the dye uptake during the dyeing, as a 40% decrease (from 0.5 to... 

CDEP against time for different package porosities, based on a Nernst adsorption isotherm. 

Figure 6.36 illustrates the influence of porosity change across the package layers on dye transfer behaviour. Dotted and dashed curves represent the CDEP when the package porosity linearly decreases from 0.5 to 0.462, and increases from 0.5 to 0.538 (or the package density increases and decreases) with distance... 

The simulation result shows that variations in package porosity have little effect on dye uptake. However, dyeings in which the porosity increases with the distance in the flow direction present a slightly better dye uptake feature, while dyeings in which the porosity decreases with the distance in the flow direction present a slightly poorer dye uptake feature. 

Package porosity strongly affects dye uptake during the dyeing process. Decreasing the porosity of the package deereases both the rate of dye uptake and DDF. 

Compaction occurs when continuous sedimentation results in an increase of overburden which expels pore water from a sediment package. Pore space will be reduced and the grains will become packed more tightly together. Compaction is particularly severe in clays which have an extremely high porosity of some 80% when freshly deposited. 

Conditioning of the Product. The high porosity and low moisture content of the freeze-dried product require that the vacuum be broken and packaging he done under a dried inert-gas blanket, in many cases, to prevent oxidation during storage and maintain the low moisture content. Carbon dioxide or nitrogen are commonly used. 

The DLC active part is made in most of the case of two identical electrodes. There is a spacer between the electrodes, called separator, whose function is to provide the electronic insulation between the electrodes, while ensuring the ionic conduction by allowing the ions to move through thanks to its porosity. The active part is impregnated with an electrolyte made of a solvent containing a disassociated salt and the unit s seated in a hermetic package [2],... 

One problem with high porosity in dehydrated foods, in addition to increased packaging requirements, is the possibility of rapid oxidation because of increased surface area of exposure to oxygen if air is present within the pores. An approach which could be used to solve the problem was first suggested by Sinnam et al. (20) when they compressed explosion puffed carrots after dehydration and found that there were no differences in the rehydration rate or rehydration ratio compared to the original explosion puffed dehydrated carrots. This concept has been extensively exploited by the U.S. Army Natick Laboratories (21) in the development of... 

Bruce, H. L., F. H. Wolfe, S. D. M. Jones, and M. A. Price. 1996. Porosity in cooked beef from controlled atmosphere packaging is caused by rapid COj gas evolution. Food Research International 29 189-193. 

For the Heron Field, original formation water concentrations (corrected elemental residual salt analyses CERSA) were back-calculated using ERSA leachate analyses, the volume of the core sample, and values for core sample porosity and from nearby core samples. Further corrections were made for H2O condensation from the oil-phase to formation water using a Shell in-house PVT package. The total dataset used in this study included analyses of 478 samples (189 water samples, 274 ERSA samples, 15 CERSA samples). 

Matrix diffusion is another mechanism that causes mixing. The rock matrix is porous with a porosity Ep in granites of typically 0.1-0. 5 %. The water in the rock matrix is stagnant. Mixing between the flowing water in the fractures and the matrix water takes place by molecular diffusion. A water package in the fracture that equilibrates with the matrix water by molecular diffusion will be diluted. A contaminant pulse travelling in a fracture will be retarded in relation to the advective velocity of the water. 

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