Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Formulation of Basic Equations

At a specified temperature, the thermal conductivity of FRP composite materials depends on the properties of the constituents at this temperature, as well as the content of each constituent As a result, if the temperature-dependent thermal conductivity is known for both fibers and resin, the property of the composite material can be estimated. During decomposition, however, decomposed gases and delaminating fiber layers will influence significantly the thermal conductivity (trae against effective thermal conductivity). An alternative method to determine the effective thermal conductivity is to suppose that the materials are only composed of two phases the undecomposed material and the decomposed material. The content of each phase can thereby be determined from the mass transfer model introduced above. As a result, the effects owing to decomposition can be described [12]. [Pg.57]

Equation 4.26 corresponds to a series model or the inverse rule of mixture as introduced in Chapter 3. Considering that phase 1 is the undecomposed material and phase 2 is the decomposed material, Eq. (4.27) can be obtained  [Pg.58]

As introduced above, kj, is the thermal conductivity of the undecomposed material composed of fibers (constituent 1) and resin (constituent 2). Accordingly, the following can be obtained  [Pg.58]


This outline, as brief and superficial as it may be (for a more detailed description of basic electrochemical transport objects, the reader is referred to relevant texts, e.g., [1]—[3]) will permit a formulation of basic equations of electro-diffusion. A hierarchy of electro-diffusional phenomena will be sketched next, beginning with the simplest equilibrium ones. Subsequent chapters will be devoted to the study of some particular topics from different levels of this hierarchy. [Pg.1]

The set of basic equations is completed by the Gibbs-Duhem (the local formulation of the second law of thermodynamics) and the Gibbs relation (which connects the pressure P with the other thermodynamic quantities), which we will use in the following form ... [Pg.110]

The theory of X-ray fluorescent emission was initially developed by Van Hamos (1945) for primary fluorescence and Gillam and Heal (1952) for secondary fluorescence. Their calculations were subsequently improved by Sherman (1956) and then Shiraiwa and Fujino (1966) who formulated the basic equations used in the quantitative application of X-ray fluorescence. [Pg.74]

These equations have general applicability for any continuous medium and are valid for any co-ordinate system. Additional information about the formulations of basic governing equations can be found in Bird et al. (1960). [Pg.40]

Typical formulation of basic model equations will be summarized later. [Pg.54]

We have presented in Sections 8.8.1 and 8.8.2 the two sets of basic equations written in terms of the flux N and the diffusive J, respectively. Here, we present another formulation which is also useful. [Pg.502]

A simple environment, in which the separation process in electrophoresis takes place, allows easy formulation of basic transport laws that describe electromigration with good exactness and enables the separation process to be understood well. For example, the approximate continuity equations that describe electromigration of n strong ions in free solution are... [Pg.947]

We know that thermodynamics is a very powerful tool for the study of systems at equilibrium, but electrode processes are systems not at equilibrium when at equilibrium there is no net flow of current and no net reaction. Therefore electrode reactions should be studied using the concepts and formalities of kinetics. Indeed, the same period that saw the flourishing of solution electrochemistry, also saw the formulation of the fundamental theoretical concepts of electrode kinetics the work of Tafel on the relationship of current and potential was published in 1905 those of Butler and Volmer and Erdey Gruz, which formulated the basic equation for electrode kinetics, were published in 1924 and 1930 respectively. Frumkin in 1933 showed the correlation between the structure of the double layer and the kinetics of the electrode process. The first quantum mechanical approach to electrode kinetics was published by Gurney in 1931. [Pg.6]

The aim of this section is to show how the modulus-phase formulation, which is the keytone of our chapter, leads very directly to the equation of continuity and to the Hamilton-Jacobi equation. These equations have formed the basic building blocks in Bohm s formulation of non-relativistic quantum mechanics [318]. We begin with the nonrelativistic case, for which the simplicity of the derivation has... [Pg.158]

Mass and Energy Balances. The formulation of mass and energy balances follows procedures outlined ia many basic texts (2). The use of solubihties to calculate crystal production rates from a cooling crystallizer was demonstrated by the discussion of equations 1 and 2. Subsequent to determining the yield, the rate at which heat must be removed from such a crystallizer can be calculated from an energy balance ... [Pg.341]

The applicability of the Born-Oppenheimer approximation for complex molecular systems is basic to all classical simulation methods. It enables the formulation of an effective potential field for nuclei on the basis of the SchrdJdinger equation. In practice this is not simple, since the number of electrons is usually large and the extent of configuration space is too vast to allow accurate initio determination of the effective fields. One has to resort to simplifications and semi-empirical or empirical adjustments of potential fields, thus introducing interdependence of parameters that tend to obscure the pure significance of each term. This applies in... [Pg.107]

Stokes law is rigorously applicable only for the ideal situation in which uniform and perfectly spherical particles in a very dilute suspension settle without turbulence, interparticle collisions, and without che-mical/physical attraction or affinity for the dispersion medium [79]. Obviously, the equation does not apply precisely to common pharmaceutical suspensions in which the above-mentioned assumptions are most often not completely fulfilled. However, the basic concept of the equation does provide a valid indication of the many important factors controlling the rate of particle sedimentation and, therefore, a guideline for possible adjustments that can be made to a suspension formulation. [Pg.261]

The utility of matrices in the applied sciences is, in many cases, connected with the fact that they provide a convenient method for the formulation of physical problems in terms of a set of equations. It is therefore important to become familiar with the manipulation of the equations, or equivalently with the manipulation of rows and columns of the corresponding matrix. First, we will be concerned with some basic tools such as column-echelon form and elementary matrices. Let us introduce some definitions (Noble, 1969). [Pg.40]

For a theoretical description of crosslinking and network structure, network formation theories can be applied. The results of simulation of the functionality and molecular weight distribution obtained by TBP, or by off-space or in-space simulations are taken as input information. Formulation of the basic pgf characteristic of TBP for crosslinking of a distribution of a hyperbranched polymer is shown as an illustration. The simplest case of a BAf monomer corresponding to equation (4) is considered ... [Pg.140]

The basic GC-model of the Constantinou and Gani method (Eq. 1) as presented above provides the basis for the formulation of the solvent replacement problem as a MILP-optimization problem. For purposes of simplicity, in this chapter, only the first-order approximation is taken into consideration (that is, W is equal to zero). In this way, the functions of the target properties of the generated molecules (solvent replacements) are written as monotonic functions of the property values, thereby, leading to a linear right hand side of the property constraints (property model equation), as follows,... [Pg.90]

In the present context, the way to ensure extensivity is to reformulate the CSE so that the RDMCs and not the RDMs are the basic variables. One can always recover the RDMs from the cumulants, but only the cumulants satisfy connected equations that do not admit the possibility of mixing noninteracting subsystems. Connected equations are derived in Section V. Before introducing that material, we first provide a general formulation of the p-RDMC for arbitrary p. [Pg.269]

We continue this chapter with a presentation of the basic concepts and notations relevant to D-functional theory (Section 111). We then review the fundaments of the NOF theory (Section IV) and derive the corresponding Euler equations (Section V). The Gilbert [15] and Pernal [81] formulations, as well as the relation of Euler equations with the EKT, are considered here. The following sections are devoted to presenting our NOF theory. The cumulant of the 2-RDM is discussed in detail in Section VI. The spin-restricted formulations for closed and open-shells are analyzed in Sections Vll and VIII, respectively. Section IX is dedicated to our further simplification in order to achieve a practical functional. In Section X, we briefly describe the implementation the NOF theory for numerical calculations. We end with some results for selected molecules (Section XI). [Pg.394]


See other pages where Formulation of Basic Equations is mentioned: [Pg.97]    [Pg.57]    [Pg.62]    [Pg.97]    [Pg.57]    [Pg.62]    [Pg.3]    [Pg.87]    [Pg.7]    [Pg.9]    [Pg.53]    [Pg.102]    [Pg.338]    [Pg.19]    [Pg.5]    [Pg.386]    [Pg.541]    [Pg.760]    [Pg.358]    [Pg.47]    [Pg.8]    [Pg.5]    [Pg.213]    [Pg.67]    [Pg.114]    [Pg.3]    [Pg.155]    [Pg.33]    [Pg.7]    [Pg.78]    [Pg.93]    [Pg.172]   


SEARCH



Basic Formulation

Basic equation

© 2024 chempedia.info