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Mathematical solution

Passage through the quadmpole assembly is described as stable motion, while those trajectories that lead ions to strike the poles is called unstable motion. From mathematical solutions to the equations of motion for the ions, based on Equation 25.1, two factors (a and q Equation 25.2) emerge as being important in defining regions of stable ion trajectory. [Pg.187]

Equation (9.74) is a one-dimensional version of Pick s second law. We shall presently consider a statistical approach to solving this equation. If c is measured as a function of x and t in an experiment which corresponds to the boundary conditions of the mathematical solution to Eq. (9.74), then D can be evaluated for the solute. We shall consider this below also. [Pg.624]

Perhaps the most significant of the partial molar properties, because of its appHcation to equiHbrium thermodynamics, is the chemical potential, ]1. This fundamental property, and related properties such as fugacity and activity, are essential to mathematical solutions of phase equihbrium problems. The natural logarithm of the Hquid-phase activity coefficient, Iny, is also defined as a partial molar quantity. For Hquid mixtures, the activity coefficient, y, describes nonideal Hquid-phase behavior. [Pg.235]

The mathematical solution for maximum vacuum is based on Eq. (26-56), which solves the NPSH equation for this value of the fluid height. The nomenclature used contains only positive numbers for elevation, with the base point being set at the tank s discharge nozzle (analogous to the gravity-discharge case). [Pg.2337]

Actually, our assumption about the way in which the plate material relaxes is obviously rather crude, and a rigorous mathematical solution of the elastic stresses and strains around the crack indicates that our estimate of 81i is too low by exactly a factor of 2. Thus, correctly, we have... [Pg.134]

Therefore the author decided to create an artificial true mechanism, derive the kinetics from the mechanism without any simplification, and solve the resulting set of equations rigorously. This then can be used to generate artificial experimental results, which in turn can be evaluated for kinetic model building. Models, built from the artificial experiments, can then be compared with the prediction from the rigorous mathematical solution of the kinetics from the true mechanism. [Pg.117]

Here a four-step mechanism is described on the framework of methanol synthesis without any claim to represent the real methanol mechanism. The aim here was to create a mechanism, and the kinetics derived from it, that has an exact mathematical solution. This was needed to perform kinetic studies with the true, or exact solution and compare the results with various kinetic model predictions developed by statistical or other mehods. The final aim was to find out how good or approximate our modeling skill was. [Pg.219]

To facilitate the use of methanol synthesis in examples, the UCKRON and VEKRON test problems (Berty et al 1989, Arva and Szeifert 1989) will be applied. In the development of the test problem, methanol synthesis served as an example. The physical properties, thermodynamic conditions, technology and average rate of reaction were taken from the literature of methanol synthesis. For the kinetics, however, an artificial mechanism was created that had a known and rigorous mathematical solution. It was fundamentally important to create a fixed basis of comparison with various approximate mathematical models for kinetics. These were derived by simulated experiments from the test problems with added random error. See Appendix A and B, Berty et al, 1989. [Pg.281]

If the state and control variables in equations (9.4) and (9.5) are squared, then the performance index become quadratic. The advantage of a quadratic performance index is that for a linear system it has a mathematical solution that yields a linear control law of the form... [Pg.274]

Baasel, W. D. and J. S. Smith, A Mathematical Solution for the Condensation of Vapors from Non-Condensing Gases in Laminar Elow Inside Vertical Cylinders, AIChE Journal, Nov. (1963) p. 826. [Pg.285]

On the other hand the Thomas-Fermi method, which treats the electrons around the nucleus as a perfectly homogeneous electron gas, yields a mathematical solution that is universal, meaning that it can be solved once and for all. This feature already represents an improvement over the method which seeks to solve Schrodinger equation for every atom separately. This was one of the features that made people go back to the Thomas-Fermi approach in the hope of... [Pg.103]

The mathematical solution for the above system is set as given by the following matrix ... [Pg.118]

A word of caution is in order at this point. There is an unrealistic tendency on the part of some to think that once the mathematical solution of a problem has been found the task of the scientist is completed, and that the effort of interpreting and applying the solution is an easy one. We must emphasize the fact that the difficulty of solving an operational problem is really encountered after the mathematical solution has been obtained i.e., in the effective application of the theoretical solution to a specific, physical problem. [Pg.255]

Margules, and Scatchard-Hildebrand) are particular mathematical solutions to Eq. (48) these models do not satisfy Eqs. (45) and (46), except in the limiting case where the right-hand sides of these equations vanish. This limiting case provides a good approximation for mixtures at low pressures but introduces serious error for mixtures at high pressures, especially near critical conditions. [Pg.160]

The exact mathematical solution of problems involving unsteady thermal conduction may be very difficult, and sometimes impossible, especially where bodies of irregular shapes are concerned, and other methods are therefore required. [Pg.401]

These three equations (11), (12), and (13) contain three unknown variables, ApJt kn and sr The rest are known quantities, provided the potential-dependent photocurrent (/ph) and the potential-dependent photoinduced microwave conductivity are measured simultaneously. The problem, which these equations describe, is therefore fully determined. This means that the interfacial rate constants kr and sr are accessible to combined photocurrent-photoinduced microwave conductivity measurements. The precondition, however is that an analytical function for the potential-dependent microwave conductivity (12) can be found. This is a challenge since the mathematical solution of the differential equations dominating charge carrier behavior in semiconductor interfaces is quite complex, but it could be obtained,9 17 as will be outlined below. In this way an important expectation with respect to microwave (photo)electro-chemistry, obtaining more insight into photoelectrochemical processes... [Pg.459]

X-rays. This was followed by the mathematical solution of crystal structure from X-ray diffraction data in 1913 by Bragg. Since that, many applications of X-ray were foimd including structure determination of fine-grained materials, like soils and days, which had been previously thought to be amorphous. Since then, crystals structures of the day minerals were well studied (Ray and Okamoto, 2003). [Pg.30]

In conventional closed-form analysis, one generally seeks to simplify the governing equations by dropping those terms which are zero or whose numerical magnitudes are small relative to the others, and then proceeding with a mathematical solution. In contrast, our code is written to contain all of the terms (except uVu, for now), and the particularization to specific problems is done entirely by the selection of appropriate numerical parameters in the input dataset. [Pg.271]

First think about the chemistry of the probiem, and then construct a mathematical solution. Use the seven-step procedure. [Pg.153]

Equilibrium conditions are determined by the chemical reactions that occur in a system. Consequently, it is necessary to analyze the chemistry of the system before doing any calculations. After the chemistry is known, a mathematical solution to the problem can be developed. We can modify the seven-step approach to problem solving so that it applies specifically to equilibrium problems, proceeding from the chemistry to the equilibrium constant expression to the mathematical solution. [Pg.1164]

The mathematical solution to moving boundary problem involves setting up a pseudo-steady-state model. The pseudo-steady-state assumption is valid as long as the boundary moves ponderously slowly compared with the time required to reach steady state. Thus, we are assuming that the boundary between the salt solution and the solid salt moves slowly in the tablet compared to the diffusion... [Pg.721]

In the last decades not only thousands of chemical descriptors but also many advanced, powerful modeling algorithms have been made available, The older QSAR models were linear equations with one or a few parameters. Then, other tools have been introduced, such as artificial neural network, fuzzy logic, and data mining algorithms, making possible non linear models and automatic generation of mathematical solutions. [Pg.83]

Similar mathematical solution can be derived from a Poisson distribution of random events in 2D space. The probability that 2D separation space will be covered by peaks in ideally orthogonal separation is analogical to an example where balls are randomly thrown in 2D space divided into uniform bins. The general relationship between the number of events K (number of balls, peaks, etc.) and the number of bins occupied F (bins containing one or more balls, peaks, etc.) is described by Equation 12.3, where N is the number of available bins (peak capacity in 2DLC). [Pg.272]

A simple mathematical solution of eq. (1.17) occurs if both Se and Qi are constant. The former hypothesis is realistic over a wide range of pressure the latter is usually only a rough approximation. [Pg.27]

Method 2 A mathematical solution is obtained by substituting the experimental values of Experiments 1 and 3 into rate-law expressions and dividing the latter by the former. Note the calculations are easier when the experiment with the larger rate is in the numerator. [Pg.260]

The rate of feed vf (in mol 1 1 s ) of the reactant into the reaction medium is now the critical parameter to adjust for a favourable outcome of a cyclisa-tion experiment. A kinetic treatment of the open system under influxion incurs the same difficulties already discussed for the closed system in Section 2. However, when the higher-order polymerisation terms are relatively unimportant and the overall process is described to a useful approximation by (6), an exact mathematical solution is possible (Galli and Mandolini, 1975). After a relatively short initial time9, the concentration of M reaches a steady value [M]st given by (72), where (3 defined by (73) is a dimensionless parameter... [Pg.104]

A standard continuous-time job-shop scheduling formulation [3] can be used to model the basic aspects of the production decisions, such as sequencing and assignment of jobs. Here, the key of the mathematical solution is to capture the durations of each processing step and to relate it to the amounts of material. Therefore, only a top-down approach will be presented to illustrate some main principles of the model. [Pg.100]

Calculations — These questions require you to quickly calculate mathematical solutions. Since you will not be allowed to use a calculator for the multiple-choice questions, the questions requiring calculations have been limited to simple arithmetic so that they can be done quickly, either mentally or with paper and pencil. Also, in some questions, the answer choices differ by several orders of magnitude so that the questions can be answered by estimation. [Pg.21]

Some insight on the effect of the parameters on the mathematical solution can be gained through a graphical procedure. The basic idea is to plot the uptake and diffusive fluxes as functions of a variable concentration on the surface cjy, (i.e. c mO o)) and seek their intersection. It is therefore convenient to introduce the diffusive steady-state (dSS, see Section 2.4 below) flux, / ss, or flux corresponding to the diffusion profile conforming to the steady-state situation for a given surface concentration ... [Pg.157]

Summary of Mathematical Solutions for Production Decline Curves... [Pg.340]

When the sorbent is initially free from solute, Equation 37 can be solved analytically (73) to give the ratio of the mass sorbed at time t to the mass sorbed at equlibrium (i.e., the fractional approach to equilibrium). The mathematical solution depends on the mass fraction ultimately sorbed from the aqueous phase (F), and is most conveniently presented in terms of t, a dimensionless time parameter given by... [Pg.209]

What kind of solution was expected from physicists As we have seen, many chemists, from Lavoisier on, expected that fundamental chemical problems would be accessible to mathematical solution, meaning not just precise quantification or geometrical explanation but algebraic formulation on mechanical principles. 32 For all the resentment of statements by Kelvin or Boltzmann that chemistry could be reduced to vortex atoms or the kinetics of atoms,33 many nineteenth-century chemists shared Kekule s vague presentiment... [Pg.292]


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See also in sourсe #XX -- [ Pg.76 ]




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