Combined effects of temperature and concentration

The flow behavior index (n) is assumed to be relatively constant with temperature and concentration, and the combined effects of temperature and concentration on the power law consistency index, K, are described by ... 

The magnitude of (kcal mole" ) increased slightly with storage time one week, 5.90 1.02 two weeks, 5.94 1.56 three weeks, 6.22 2.99 four weeks, 7.91 2.52. The combined effect of temperature and concentration was modeled using an equation similar to 5.13 and the results are given in Table 5-1. 

The Combined Effect of Temperature and Concentration on the Consistency Coefficient of Milk Concentrates In fC = + ( where X is... 

Absence of combined effect of temperature and concentration gradients... 

The effect of temperature, although significant, is not nearly as great as that from the ethanol content and is greatest at low concentrations of the polar solvent. It is clear, that the solute retention is the least at high ethanol concentrations and high temperatures, which would provide shorter analysis times providing the selectivity of the phase system was not impaired. The combined effect of temperature and solvent composition on selectivity, however, is more complicated and to some extent... 

In Lab 17.1, you learned about the effect of temperature and concentration on reaction rate. Another factor that affects reaction rate is the amount of surface area of the reactants. If a chemical reaction is to take place, the molecules of reactants must collide. Changing the amount of surface area modifies the rate of collision, and, thus, the rate of reaction. If surface area increases, collision frequency increases. If surface area decreases, so does the number of collisions. In this lab, you will examine the effect of surface area on rate of reaction. You will also determine how a combination of factors can affect reaction rate. 

The effect of temperature and concentration on the viscosity of concentrated apple juice can be combined to obtain a single approximate equation that can be used for estimating viscosity as a function of both temperature and concentration (°Brix) ... 

In the liquid phase the loss of light (low C/H atomic ratio) species from the surface causes a concentration profile to be established for each compound. The lighter compounds, being deficient at the surface, diffuse to the surface and the heavier compounds, being concentrated at the surface, diffuse towards the center of the droplet. The combined effects of vaporization and diffusion determine the surface composition and thereby the surface temperature. This combination of temperature and composition determines the relative volatilities of the species present at the surface and hence the vapor phase composition. 

Castillo, M., Lucey, J.A., and Payne, F A. (2006). The effect of temperature and inoculum concentration on rheological and light scatter properties of milk coagulated by a combination of bacterial fermentation and chymosin cottage cheese-type gels. Int. Dairy J. 16, 131-146. 

Since both albedo and gas adsorption depend on SSA, the climate response of the concentration of species adsorbed within the snowpack will be similar to that of albedo increase in regions where warming is accompanied by a change from HGM to QIM, such as the southern taiga and the warmer Alpine areas in the fall and decrease in the other regions. These effects will be modulated by the temperature increase, that will decrease the concentration of adsorbed species. For example, a temperature rise from -15 to -10 °C will desorb 40% of adsorbed acetone molecules, that have an adsorption enthalpy of 57 kJ/mol,, at constant SSA. The combined effect of warming and SSA change will then probably lead to a decrease in the concentration of adsorbed species in most areas. 

Among other factors that may influence the removal of metal ions by activated carbon, different surveys have pointed out the combined effect of initial metal concentration and activated carbon dosage with a decrease in adsorption as the metal/carbon ratio increases [24, 25], or of temperature [26]. 

A summary of intraparticle transport criteria is given in Table 7.2. The most general of the criteria, 5(a) of Table 7.2, ensures the absence of any net effects (combined) of temperature and concentration gradients but does not guarantee that this may not be due to a compensation between heat- and mass-transport rates. (In fact, this is the case when y/f ). It may therefore be the most conservative general policy to see that the separate criteria for isothermality are met, for example, by the combination of 3 and 5(c), or of 3 and 4 in Table 7.2. The presentations of Table 7.2 deal with power-law kinetics only more complicated issues, such as what to do with complex kinetics or reactions involving volume change, have also been treated in the literature and are summarized by Mears [reference 5(b) in Table 7.2]. 

Figure 2 shows the concentration of soil nitrate values observed in the trial period. For all the treatments, the tendency is characterised by high values in the summer due to the combined effect of fertilisation and native soil N mineralisation, since, in this season, soil conditions are not limiting for biochemical activities (optimal soil water contents maintained by micro irrigation and high soil temperature). On the other hand, low values measured in the winter could be ascribed to the rainfall that may leach nitrates from the superficial soil layer. 

In this relation. T is the temperature at optimum formulation where R = t, i.e.. [he PIT according to Shinoda s prcmi.se, an expression that deserves the latter label HLB-temperature. This relationship is very close to the one deduced b some re.searchers (78) who used the surfactant HLB instead EON-a to arrive to u similar result as far as the combined effects of temperature, salinity, and oil ACN are concerned. The above formula indicates how the PIT increases with the number of ethylene oxide groups in the surfactant molecule, increases with oil chain length, and decreases with electrolyte concentraiion and surfactant tail length (proportionally to a). It also predicts a variation with the alcohol type and concentration, a decrease with lipophilic. species. 

EIS with systematic variation of pH, primary (i.e. Zn", Br ) and secondary (e.g. Cr, K ) electrolyte species concentrations, as well as type of BSA used Study impact of individual electrochemical contributions to impedance at electrical double-layer, etc., in system during charge/discharge Need to systematically test various combinations of electrolyte and BSA concentrations, including effects of temperature and pH, as well as confirming reproducibiUty of results... 

This equation also gives a relationship between the mass balance equations for each component (3.32) and the heat balance in (3.34) allowing an analytical solution after insertion of the boundary conditions (3.33) and (3.35) [113]. This allows calculations of temperatures and concentrations in the interior of a catalyst particle from the key component concentrations in the particle and the temperature and concentration at the surface. The next step is to combine this solution with the surface heat and mass flux equations (3.36) and the equation defining the effectiveness factor in Equation (3.37) by use of the surface mass flux relations for the key components [113]. The final equation is ... 

The effective reaction rate tm eff (related to the mass of catalyst/solid) already considers all extra- and intraparticle mass and heat transfer effects (Sections 4.5-4.7). Thus the pseudo-homogeneous model does not distinguish between the conditions in the fluid and in the sohd phase, as more sophisticated heterogeneous models do, as discussed, for example, in Baerns ef al. (2006), Froment and Bischoff (1990), and Westerterp, van Swaaij, and Beenackers (1998). Thus, gradients of temperature and concentration within the particle and in the thermal and diffusive boundary layers are combined by the use of an overall effectiveness factor that enables the system of four equations (mass and heat balances for solid and fluid phase) to be replaced by just two equations, Eqs. (4.10.125) and (4.10.126). 

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