Influence of Density

Density is important in achieving proper mixing of the inhibitor in the corroding stream. High-density inhibitors have heen developed for batch treating a two-phase system, such as an oil well, where getting the inhibitor to the proper location is a particular problem. 

These inhibitors consist of very tight emulsions containing high-density materials. The emulsions break slowly to release the inhibitor after the formulation has reached the greatest depth in the system. These formulations cannot be diluted when added to the system. 

The effects of mixing the inhibitor, either concentrated or dilute, with the environment of the treated system can be related to inhibitor efficiency and to treatment techniques, and are frequently the cause of undesirable side effects. 

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In a practical sense, stability of a dispersion ofttimes is accompanied by a retarded separation of the phases. Unfortunately, a quantitative definition cannot be based on this rate of separation because of the overwhelming influence of density, viscosity, and thermal effects. In short, a kinetic criterion, such as sedimentation rate, is not as likely to portray stability as one based on thermodynamic considerations. In this latter category are sediment volumes, turbidity, consistency, and electrical behavior. 

Influence of Density and Temperature on the Microscopic Structure and the Segmental Relaxation of Polybutadiene. 

The method of structural foam moulding permits the manufacture of foams with a compact skin and a cellular core. The properties of such mouldings depend, among other parameters, on the structure of the foam. This article reports on a study of the influence of density, specimen thickness, orientation and ambient temp, on mechanical properties and chemical resistance of injection monlded structural foams made from PP. Results are discussed with reference to relationships between structnre and properties. 5 refs. 

Stanyukovich Shekhter (1959), 242-45 289-95 (Influence of density on deton velocity) 9)Andreev Belyaev (I960), 193-94 (Formula and table for calcg vel in relation to density) 204-06 (Influence of densities on deton velocities for some expls)... 

Influence of density on deton vel of gases, discussed on p 244, includes a statement that deton vel of 2H2 + O mixts increase f rom 3000 to 4400 nv/sec, when density is increased from 0.1 0.5 g fee. 

Zlokarnik M. Influence of density and viscosity differences on mixing time in the homogenisation of liquid mixtures (in German). Chem Ing Tech 1970 42 1009-1011. 

Clifford, Rayner and co-workers at the University of Leeds [66,67] have used the density of SCCO2 to control the stereoselectivity of reactions in a novel way. Previous workers have observed an influence of density on selectivity in reactions very close to the critical point. The novelty of the Leeds work is that the effects are observed at densities considerably above pc and temperatures higher than Tc. This selectivity has no obvious counterpart in reaction chemistry in conventional solvents. Effects have been observed in a whole range of reactions, and this approach may well have widespread applicability. 

Figure 6. Influence of density on the spectral full-width-at-half maximum (FWHM) for 10 pM PRODAN in supercritical CF3H.

Carter, D.R. and Hayes, W.C. (1976) Bone compressive strength the influence of density and strain rate. Science 194 174-1175... 

The lifetime (Ti) of a vibrational mode in a polyatomic molecule dissolved in a polyatomic solvent is, at least in part, determined by the interactions of the internal degrees of freedom of the solute with the solvent. Therefore, the physical state of the solvent plays a large role in the mechanism and rate of VER. Relaxation in the gas phase, which tends to be slow and dominated by isolated binary collisions, has been studied extensively (11). More recently, with the advent of ultrafast lasers, vibrational lifetimes have been measured for liquid systems (1,4). In liquids, a solute molecule is constantly interacting with a large number of solvent molecules. Nonetheless, some systems have been adequately described by isolated binary collision models (5,12,13), while others deviate strongly from this type of behavior (14-18). The temperature dependence of VER of polyatomic molecules in liquid solvents can show complex behavior (16-18). It has been pointed out that a change in temperature of a liquid solute-solvent system also results in a change in the solvent s density. Therefore, it is difficult to separate the influences of density and temperature from an observed temperature dependence. 

Fig. 7.5. (A) Density-pressure isotherms for carbon dioxide. (B) Influence of density on the kinetics of the supercritical fluid extraction of trans-fi-caroXene at 40°C. (Reproduced with permission of Elsevier.)...

The influence of density inhomogeneities in the vicinity of the interface on the PCF is visualized in the most simple way by calculating the RDFs separately when one particle, call it i, is located in a certain distance interval from the surface. These functions then predominantly characterize the effect of inhomogeneity but also some aspects of the anisotropy of the correlations. Figures 13 and 14 show the atom-atom RDFs g-,j for the i particle located in the first (full) and second (dashed) water layer near the Pt(lOO) surface and the Hg(l 11) surface, respectively. 

Figure 4.7-6 Influence of density on the distribution of products obtained firom RCM (macFOcycle) or ADMET (oligomers) during the metathesis of an unsaturated ester in SCCO2 using catalyst 16. Data taken flx>m Reference [6].

To estimate the influence of partial coupling of the processes the simulation was also performed using T-H and C-H models. Figure 4 shows evolution in time of vertical positions of TDS and activity plumes mass centers. This figure shows the different influences of the modeled processes on the TDS and activity. These plumes are stratified in the vertical direction due to the influence of thermal viscosity effects on nuclides transport and influence of density-concentration relation on TDS transport. 

Moreover the effect of chemical reaction rate constant and also of some physical parameters of liquid flows (density, viscosity) on conditions of characteristic macroscopic fronts formation in turbulent flows limited by impenetrable wall allows supposing the various nature of reaction and mixing fronts formation. In the first case kinetic and diffusion process parameters are determinant, and in the second - preliminary convective and turbulent transfer. The influence of density and viscosity of liquid flows, i.e. parameters determining hydrodynamic regime of liquid flows in tubular canals on conditions of reaction and mixing plan front formation shows the important role of hydrodynamic constituent also in general case under corresponding macrostructures formation. 

Muller, I. The influence of density gradients on forces in a mixtures. J. Non-Equihb.Thermodyn. 2, 133-138 (1977)... 

Moreover, the influence of the chemical reaction rate constant and some other physical parameters of the liquid flow (density, viscosity) on the conditions of macroscopic front formation in turbulent flows, allow us to make an assumption about the differences in the nature of the reaction front and mixing front formation. In the first case, the key parameters of the process are the kinetic and diffusion parameters in the second case, however, the key parameters of the process are the convective and turbulent transfer. The influence of density and viscosity, i.e., the parameters which define the hydrodynamic motion mode of the liquid flow in the tubular channels, on the... 

R. Suardiaz, C. Perez, R. Crespo-Otero, J.M. Garcia de la Vega, J. San Fabian, Influence of density functionals and basis sets on one-bond carbon-carbon NMR spin-spin couphng constants, J. Chem. Theor. Comput. 4 (2008) 448-456. 

Influence of Density and Dimensionality on Quantum Confinement Effects... 

A tabulation of minimum critical values, including mass, volume, dimension, concentration, and enrichment, starts the second lecture, which continues with the Influence of density and dilution Of fissile material. The balance of toe session is devoted to interaction between subcrltical units, the criticality of arrays, array moderar tion and reflection effects, and the effective isolation of units by neutron-absorbing materials. 

The data in Figure 2.9 demonstrate the marked influence of density on the creep behavior of polyethylene. The curves in Figure 2.9 are relevant to a total strain of 1%, but similar plots for other permissible strains can be readily derived from the isochronous stress-strain curves. The linear relationship between creep and density for polyethylene at room temperature, irrespective of the melt index over the range investigated (i.e., 0.2-5.5), has enabled the stress-time curve of Figure 2.10 to be interpolated for the complete range of polyethylene. In this case, the data have been based on a permissible strain of 2%, but as previously explained, data for other permissible strains can be similarly interpolated from the creep curves. 

TABLE 17.10 Influence of Density on the Impact Strength of Unfoamed and Microcellnlar Foamed PLA [2]... 

Devereus JE, Newton JM, Short MB. The influence of density on the gastrointestinal transit of pellets. J Pharm Pharmacol 1990 42 500 501. 

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