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Mathematical model force component

Theoretical representation of the behaviour of a hydrocyclone requires adequate analysis of three distinct physical phenomenon taking place in these devices, viz. the understanding of fluid flow, its interactions with the dispersed solid phase and the quantification of shear induced attrition of crystals. Simplified analytical solutions to conservation of mass and momentum equations derived from the Navier-Stokes equation can be used to quantify fluid flow in the hydrocyclone. For dilute slurries, once bulk flow has been quantified in terms of spatial components of velocity, crystal motion can then be traced by balancing forces on the crystals themselves to map out their trajectories. The trajectories for different sizes can then be used to develop a separation efficiency curve, which quantifies performance of the vessel (Bloor and Ingham, 1987). In principle, population balances can be included for crystal attrition in the above description for developing a thorough mathematical model. [Pg.115]

Quantum mechanical calculations on small molecule association suggest that there are five major contributions to the energy of intermolecular interactions in the gas phase (3, 4). The sum of these is the dissociation energy of the intramolecular complex represented in Fig. 4.1. Table 4.1 contains some examples of magnitudes of the different energy components for different interactions. This section provides a qualitative introduction to these forces. Section gives and overview of mathematical models suitable for computer calculations. [Pg.171]

The many theories behind the various models developed to calculate the solubility of polymers, and to predict the ability of liquids to dissolve them, are described clearly and in high detail by Burke (Burke, 1984). All define a term known as solubility parameter for liquids and polymers using one or more of the intermolecular force components and represent the parameter in two or three dimensions. Calculating solubility parameters is a mathematically complex process which will not be discussed here. The most widely used method today for predicting whether a polymer is soluble in a liquid was developed by Charles M. Hansen in 1966. Hansen parameters ( ) for solvents and polymers are calculated from the dispersion force component ( d), polar component ((5p) and hydrogen bonding component ( h) for each using the formula ... [Pg.96]

Stress analysis is the determination of the relationship between external forces applied to a vessel and the corresponding stress. The emphasis of this book is not how to do stress analysis in particular, but rather how to analyze vessels and their component parts in an effort to arrive at an economical and safe design—the difference being that we analyze stresses where necessary to determine thickness of material and sizes of members. We are not so concerned with building mathematical models as with providing a step-by-step approach to the design of ASME Code vessels. It is not necessary to find every stress but rather to know the... [Pg.1]

Mathematical models of ACEO follow other examples of ICEO, as described in the article on nonlinear electrokinetic phenomena. A major simplification in the case of small voltages is to assume sinusoidal response to sinusoidal AC forcing and solve only for the complex amplitudes of the potential and velocity components at a single frequency co (Fourier mode) [2]. In this regime, the basic scaling of time-averaged ACEO flow is... [Pg.12]

Thus, the mathematical model (2), (6), (7), (8) describes the change in the velocity field in the formation of thrombus in the vessel. To simulate the obstacles of arbitrary shape (in this problem blood clot) is introduced by a discretetime artificial power. This force is applied only on the surface and within the constraints of the body. Force application point disposed in a spaced, similar velocity components defined on a staggered grid. When the point of application of force coincides with a virtual border, an artificial force is applied so as to satisfy the boundary conditions on the obstacle. The cell containing the virtual boundary, does not satisfy the equation of conservation of mass. Therefore, we introduce the source / drain weight to the cell that contains the virtual border. Discrete in time force is used to meet the conditions of adhesion on a virtual border, while the source / drain weight, to meet the conservation of mass for the cell that contains the virtual boundary. Procedure nondimensionalization this system involves choosing the characteristic scales the concentrations Oq and 4>q, lines size L, the characteristic scale of velocity V. In view of the above equations (1) - (2) takes the form ... [Pg.111]

Step 1. Nonlinear wind model. Wind is defined as the movement of air relative to the surface of the Earth. Mathematical models of wind forces and moments improve performance and robustness of the system in extreme conditions. The nature of the nonlinear component depends on the water area of MWTO operation. The appropriate spectral characteristics may also he used. [Pg.28]

We begin the mathematical analysis of the model, by considering the forces acting on one of the beads. If the sample is subject to stress in only one direction, it is sufficient to set up a one-dimensional problem and examine the components of force, velocity, and displacement in the direction of the stress. We assume this to be the z direction. The subchains and their associated beads and springs are indexed from 1 to N we focus attention on the ith. The absolute coordinates of the beads do not concern us, only their displacements. [Pg.185]

Contrary to empirical approaches, a fundamental approach has value in that the results demonstrate the validity or otherwise of a particular mechanism or model chosen for the system. For example, the application of thermodynamics to an ion exchange system does not necessarily require the setting up of a physicochemical model, but eventually the results must still be interpreted in terms of the molecular forces acting within the system. Selected molecular models enable the mechanisms of ion exchange phenomena to be better interpreted, but their success must be measured in terms of predicted accuracy which in turn depends upon the validity of the model and the accessibility of the various molecular parameters. Ideally, the mathematical equations describing the perfect model would contain quantities which were derived from the known fundamental data for the components of the system. [Pg.91]

The most rigorous formulation to describe adsorbate transport inside the adsorbent particle is the chemical potential driving force model. A special case of this model for an isothermal adsorption system is the Fickian diffusion (FD), model which is frequently used to estimate an effective diffusivity for adsorption of component i (D,) from experimental uptake data for pure gases.The FD model, however, is not generally used for process design because of mathematical complexity. A simpler analytical model called linear driving force (LDF) model is often used. ° According to this model, the rate of adsorption of component i of a gas mixture... [Pg.32]

Mechanical forces, stresses, strains, and velocities play a critical role in many important aspects of cell physiology, such as cell adhesion, motility, and signal transduction. The modeling of cell mechanics is a challenging task because of the interconnection of mechanical, electrical, and biochemical processes involvement of different structural cellular components and multiple timescales. It can involve nonlinear mechanics and thermodynamics, and because of its complexity, it is most hkely that it will require the use of computational techniques. Typical steps in the development of a cell modeling include constitutive relations describing the state or evolution of the cell or its components, mathematical solution or transformation of the corresponding equations and boundary conditions, and computational implementation of the model. [Pg.1047]

The present paper will put forward the point that a Bayesian framework may be viewed as rather natural for tackling issues (a) and (b) altogether. Indeed, beyond the forceful epistemological and decision-theory feamres of a Bayesian approach, it includes by definition a double-level probabilistic model separating epistemic and aleatory components and offers a traceable process to mix the encoding of engineering expertise inside priors and the observations inside an updated epistemic layer that proves mathematically consistent even when dealing with very low-size samples. [Pg.1700]

A sound wave is manifested as one kind of the atmospheric normal modes, known as the acoustic mode, and is caused by the compressibility of air. There are two more kinds One is called the gravity-inertia mode, which is caused by a combinations of the restitutive force of gravity against thermally stable atmospheric stratification and the Coriolis force due to the earth s rotation. The other kind is called the rotational or planetary mode, which is caused by the meridional variation of the Coriolis force. The importance of the latter kind of normal mode as a prototype of upper tropospheric large-scale disturbances was clarified by C. -G. Rossby and his collaborators a little over one decade prior to the dawn of the numerical prediction era (see Section I). In retrospect, the very natrrre of this discovery was hidden in complicated calcnlations for the normal modes of the global atmospheric model. The mathematical analysis was initiated by the French mathematician Marquis de Laplace (1749-1827), and the complete solntions became clear only with the aid of electronic compnters. It is remarkable that Rossby was able to capture the essence of this important type of wave motion, now referred to as the Rossby wave, from a simple hydrodynamic principle of the conservation of the absolute vorticity that is expressed by the sum of the vertical component of the relative vorticity and the planetary vorticify /. [Pg.369]

A more subtle temptation is to generate the mixmres by successive dilution. Two or more mixtures that vary in concentration by only a factor will in reality produce the same spectral vectors. That is, the spectra are identical except that one has a different scale to the other. Mathematically, the two spectra represent the same ratios of components and they are not different. The two spectra force the absorbance matrix A to be collinear, but more important, the concentration ratios in the C matrix are also collinear. The A matrix will have noise associated with each spectrum, and as the noise is not the same in each spectrum, the A matrix will be only approximately collinear. C will be precisely collinear, and if C is inverted (even through pseudoinversion), the result will be indeterminate that is, it is equivalent to division by zero. As soon as this happens, the regression fails and the model is invalid. [Pg.220]

Non-DC earthquake mechanisms, by definition, require for their description a more general mathematical formalism than the DC model. The most widely used such formalism is the expansion of the elastodynamic field in terms of the spatial moments of the equivalent-force system (Gilbert 1970). Usually, attention is restricted to second moments, and thus to second-rank moment tensors, and moreover these tensors are usually assumed to be symmetric, so that they have six independent components (A DC has four independent components.). This restriction is not always justified, however. Sources involving net forces or torques are theoretically possible, and phenomena such as landslides and volcanic eruptions provide clear examples of them. [Pg.1567]


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