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Osmotic pressure internal

Exxon products appear to release via a unique mechanism. Like other polymer-coated technologies, the penetration of water iato the granule is purely by diffusion. However, as water enters the particle, an osmotic pressure is created as the fertilizer is solubilized. This pressure causes an expansion of the elastomeric coating and the particle swells to many times its original diameter. As the particle swells, the coating becomes increasingly thinner to the point where it caimot contain the internal pressure and the nutrient is released. [Pg.137]

Lactam antibiotics are bicyclic or monocyclic azetidinone ring-containing compounds (Fig. 1). They kill bacteria by preventing the assembly of (4-3) peptidoglycans. These covalently closed net-like polymers form the matrix of the cell wall by which the bacteria can divide and multiply, despite their high internal osmotic pressure. [Pg.679]

We can speculate from this viewpoint that water stress involves the generation of an internal osmotic pressure greater than that accommodated... [Pg.101]

The situation changes when there is a concentration imbalance. Figure 12-15 shows red blood cells immersed in solutions of different concentrations. When the fluid outside the cell has a higher solute concentration, the result is slower movement of water through the membrane into the cell. The net result is that water leaves the cell, causing it to shrink. When the fluid outside the cell has a lower concentration, movement of water into the cell increases. The extra water in the cell causes an increase in internal pressure. Eventually, the internal pressure of the cell matches the osmotic pressure, and water transport reaches dynamic equilibrium. Unfortunately, osmotic pressures are so large that cells can burst under the increased pressure before they reach equilibrium. [Pg.864]

They showed further that the limiting slope (RTA2) of the plot of the osmotic pressure-concentration ratio tz/c against the polymer concentration in a binary solvent mixture should be proportional to the value of the quantity on the left side of Eq. (17),f with V2 representing the volume fraction of solvent in the nonsolvent-solvent mixture which is in osmotic equilibrium with the solution. The composition of the liquid medium outside the polymer molecules in a dilute solution must likewise be given by V2. The composition of the solvent mixture within the domains of the polymer molecules may differ slightly from that outside owing to selective absorption of solvent in preference to the nonsolvent. This internal composition is not directly of concern here. If the solution is made sufficiently dilute, the external nonsolvent-solvent composition v2 = l—Vi) will be practically equal to the over-all solvent composition for the solution as a whole. Hence... [Pg.551]

In order to utilise our colloids as near hard spheres in terms of the thermodynamics we need to account for the presence of the medium and the species it contains. If the ions and molecules intervening between a pair of colloidal particles are small relative to the colloidal species we can treat the medium as a continuum. The role of the molecules and ions can be allowed for by the use of pair potentials between particles. These can be determined so as to include the role of the solution species as an energy of interaction with distance. The limit of the medium forms the boundary of the system and so determines its volume. We can consider the thermodynamic properties of the colloidal system as those in excess of the solvent. The pressure exerted by the colloidal species is now that in excess of the solvent, and is the osmotic pressure II of the colloid. These ideas form the basis of pseudo one-component thermodynamics. This allows us to calculate an elastic rheological property. Let us consider some important thermodynamic quantities for the system. We may apply the first law of thermodynamics to the system. The work done in an osmotic pressure and volume experiment on the colloidal system is related to the excess heat adsorbed d Q and the internal energy change d E ... [Pg.150]

The signal generated by the complex is governed by several physical phenomena associated with the matrix thickness. As soon as the probe is placed in contact with the analyte, external mass transfer controls the movement of the analyte toward the surface of the optical probe.(S4) The osmotic pressure and Gibbs free energy dictate the permeation of the analyte into the matrix. Once the analyte has penetrated the matrix, internal mass transfer resistance controls the movement of the analyte in the matrix. Eventually, the probe reaches a steady state of equilibrium with molecules continuously moving in and out of the matrix. [Pg.200]

Under osmotic pressure gradients between the two aqueous phases of W/OAV emulsions, water may migrate either from the internal to the external phase or vice versa, depending on the direction of the osmotic pressure gradient. This process is entropically driven and is another manifestation of compositional ripening. Such... [Pg.187]

As a result of Internal concentration polarization, the effective osmotic pressure difference across the membrane can be significantly below the osmotic pressure difference between the bulk solutions. The effective osmotic pressure can be calculated from the salt permeation coefficient and the salt diffusion resistance in the porous membrane substrate. The highest power output for a membrane is obtained at an operating pressure equal to about one half of the effective osmotic pressure. [Pg.90]

Therein, the quantities c+ and r t indicate the ion concentrations of the external solution. The osmotic pressure 7r is computed from the osmolarity difference of the internal and the external solution ... [Pg.74]

Moreover, with the electroneutrality condition (18)2, the equations (16) and (17) can be used to compute the equilibrium concentration and the osmotic pressure of the internal solution [3] ... [Pg.74]


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