Big Chemical Encyclopedia

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

Articles Figures Tables About

Matrices identifiability

On the other hand, difficulty has been found in detecting the reaction intermediates using ESR spectroscopy. Initial studies39 with aryl halides using this technique at low temperature in solid matrices identified the n and a radical-anions of Phi. Dissociation of the radical anion (Phi)- to phenyl radical and iodide anion was also observed. These studies therefore provided evidence for the first two steps in the aromatic S l mechanism. [Pg.1400]

The best way to do this is to assign consecutive numbers to the samples as they are being collected. If different matrices are sampled, sample ID may include a matrix identifier. Examples of such sample numbers are S-001, S-002, W-003, W-004, WP-005, WP-006. The first two samples are soil, the next two are water, and the last two are wipes. [Pg.95]

M is a singular Matrix. Zero entries on the main diagonal of this matrix identify the algebraic equations, and all other entries which have the value 1 represent the differential equation. The vector x describes the state of the system. As numeric tools for the solution of the DAE system, MATLAB with the solver odel5s was used. In this solver, a Runge Kutta procedure is coupled with a BDF procedure (Backward Difference Formula). An implicit numeric scheme is used by the solver. [Pg.479]

Speciation analysis Analytical activity of identifying and measuring species in a real and representative sample or matrix Identifying and measuring strictly includes quality control... [Pg.538]

The creation of access control gnidelines is a user-centered activity. Access control gnidelines are often developed as a matrix identifying the various classes of users, the various classes of data or information, and the access privileges (e.g., write, alter, read only) for each combination of nser class and data class. [Pg.635]

The dimensions of a matrix are by row and column, or i and j. Usually, the matrix values or elements are lettered as Ujj for the value a and its location in the th row and/th column. Notations for the matrix identifiers. A, B, X, and Y, are always a capital bold letter. The exception is the vector, which is usually denoted by a small bold letter, but this is not always the case in statistical applications. [Pg.481]

Performance criteria for TOC removal based on raw water TOC levels and alkalinity have been established to serve as a definition of enhanced coagulatioa Table V presents a matrix identifying the percent TOC removal required based on raw water TOC and alkalinity levels. If a conventional treatment plant can not achieve the percent reductions listed in Table V, the system can use an alternative criteria for evaluating enhanced coagulation. This alternative criteria requires a system to conduct bench- or pilot-scale studies to identify optimum coag-rrlation conditiorrs. [Pg.16]

The first to be used was coal gas. Composed mostly of hydrogen, carbon monoxide, and hydrocarbons, coal gas can be explosive and toxic, but it contains traces of sulfur compounds (natural or added) that give it the rotten-egg smell that indicates a gas leak. This gas was used for illuminating houses and streets beginning in the early 1800s, and it was the gas Bunsen used to fuel his Bunsen burner for spectroscopic studies. Coal tar found its first use as a wood preservative, but coal tar is a complex mixture of aromatic organic compounds, including benzene, toluene, xylenes, naphthalene, phenols, and anthracene as more compounds were isolated from its matrix, identified, and studied, coal tar became the basis for an entirely new chemistry. [Pg.284]

The decision matrix identifies no requirement for notified body involvement for the Machinery Directive because the product is not special equipment according to the Machinery Directive (EC 2006a) Article 12 and Annex IV. Also, because our complex product is not partially completed equipment for incorporation into other apparatus, a declaration of incorporation (D of 1) drawn up in accordance with Annex IIB of the Machinery Directive is not required. [Pg.266]

X-ray fluorescence A method of analysis used to identify and measure heavy elements in the presence of each other in any matrix. The sample is irradiated with a beam of primary X-rays of greater energy than the characteristic X-radiation of the elements in the sample. This results in the excitation of the heavy elements present and the emission of characteristic X-ray energies, which can be separated into individual wavelengths and measured. The technique is not suitable for use with elements of lower atomic number than calcium. [Pg.429]

The formation bulk density (p ) can be read directly from the density log (see Figure 5.51) and the matrix density (p J and fluid density (p,) found in tables, assuming we have already identified lithology and fluid content from other measurements. The equation can be rearranged for porosity ((])) as follows ... [Pg.146]

Figure Al.6.18. Liouville space lattice representation in one-to-one correspondence with the diagrams in figure A1.6.17. Interactions of the density matrix with the field from the left (right) is signified by a vertical (liorizontal) step. The advantage to the Liouville lattice representation is that populations are clearly identified as diagonal lattice points, while coherences are off-diagonal points. This allows innnediate identification of the processes subject to population decay processes (adapted from [37]). Figure Al.6.18. Liouville space lattice representation in one-to-one correspondence with the diagrams in figure A1.6.17. Interactions of the density matrix with the field from the left (right) is signified by a vertical (liorizontal) step. The advantage to the Liouville lattice representation is that populations are clearly identified as diagonal lattice points, while coherences are off-diagonal points. This allows innnediate identification of the processes subject to population decay processes (adapted from [37]).
For large Cl calculations, the frill matrix is not fonned and stored in the computer s memory or on disk rather, direct CF methods [ ] identify and compute non-zero and inunediately add up contributions to the sum jCj. Iterative methods [, in which approximate values for the Cj coefficients are refined tlirough sequential application of to the preceding estimate of the vector, are employed to solve... [Pg.2177]

A major disadvantage of a matrix representation for a molecular graph is that the number of entries increases with the square of the number of atoms in the molecule. What is needed is a representation of a molecular graph where the number of entries increases only as a linear function of the number of atoms in the molecule. Such a representation can be obtained by listing, in tabular form only the atoms and the bonds of a molecular structure. In this case, the indices of the row and column of a matrix entry can be used for identifying an entry. In essence, one has to distinguish each atom and each bond in a molecule. This is achieved by a list of the atoms and a list of the bonds giving the coimections between the atoms. Such a representation is called a connection table (CT). [Pg.40]

We shall initially consider a closed-shell system with N electroris in N/2 orbitals. The derivation of the Hartree-Fock equations for such a system was first proposed by Roothaan [Roothaan 1951] and (independently) by Hall [Hall 1951]. The resulting equations are known as the Roothaan equations or the Roothaan-Hall equations. Unlike the integro-differential form of the Hartree-Fock equations. Equation (2.124), Roothaan and Hall recast the equations in matrix form, which can be solved using standard techniques and can be applied to systems of any geometry. We shall identify the major steps in the Roothaan approach. [Pg.76]

Step 1 To solve a Stokes flow problem by this program the inertia term in the elemental stiffness matrix should be eliminated. Multiplication of the density variable by zero enforces this conversion (this variable is identified in the program listing). [Pg.215]

Step 3 Comparing systems (7.2) and (7.3) additional terms in the members of the stiffness matrix corresponding to the axisymmetric fon-nulation are identified. Note that the measure of integration in these tenns is (r drdz). [Pg.216]

Polymer-based rocket propellants are generally referred to as composite propellants, and often identified by the elastomer used, eg, urethane propellants or carboxy- (CTPB) or hydroxy- (HTPB) terrninated polybutadiene propellants. The cross-linked polymers act as a viscoelastic matrix to provide mechanical strength, and as a fuel to react with the oxidizers present. Ammonium perchlorate and ammonium nitrate are the most common oxidizers used nitramines such as HMX or RDX may be added to react with the fuels and increase the impulse produced. Many other substances may be added including metallic fuels, plasticizers, stabilizers, catalysts, ballistic modifiers, and bonding agents. Typical components are Hsted in Table 1. [Pg.32]


See other pages where Matrices identifiability is mentioned: [Pg.79]    [Pg.119]    [Pg.77]    [Pg.62]    [Pg.41]    [Pg.823]    [Pg.1725]    [Pg.140]    [Pg.165]    [Pg.40]    [Pg.192]    [Pg.208]    [Pg.323]    [Pg.781]    [Pg.44]    [Pg.654]    [Pg.186]    [Pg.84]    [Pg.546]    [Pg.550]    [Pg.677]    [Pg.139]    [Pg.230]    [Pg.283]    [Pg.61]    [Pg.120]    [Pg.128]    [Pg.128]    [Pg.394]    [Pg.161]    [Pg.344]    [Pg.52]    [Pg.54]    [Pg.106]   
See also in sourсe #XX -- [ Pg.40 , Pg.315 ]

See also in sourсe #XX -- [ Pg.315 ]




SEARCH



Identifying Nonzero Matrix Elements

Modal matrix, identifiability

© 2024 chempedia.info