Big Chemical Encyclopedia

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

Articles Figures Tables About

Displacement due

Adaptations of this method have been proposed in order to take into account the band displacement due either to substitution on the aromatic ring, or to chains of different lengths. The variations consist, instead of measuring the absorbance at maximum absorption, of an integration of the absorbance curve over a specified range (Oelert s method, 1971). More exact, this method is used less often mainly because the Brandes method is simpler... [Pg.61]

This is the factor by which the echo magnetization is attenuated as a result of difhision. More elaborate calculations, which account for phase displacements due to difhision occurring during the application of the gradient pulses yield... [Pg.1540]

Table 10-56 gives values for the modulus of elasticity for nonmetals however, no specific stress-limiting criteria or methods of stress analysis are presented. Stress-strain behavior of most nonmetals differs considerably from that of metals and is less well-defined for mathematic analysis. The piping system should be designed and laid out so that flexural stresses resulting from displacement due to expansion, contraction, and other movement are minimized. This concept requires special attention to supports, terminals, and other restraints. [Pg.1004]

Bevel, zerol Same ratings as straight bevel gears and use same mountings, permits slight errors in assembly, permits some displacement due to deflection under load, highly accurate, hardened due to grinding Limited to speeds less than 1000 fpm due to noise... [Pg.575]

Then, the components of stresses and displacements, due to a temperature increase of the material equal to AT, are expressed by ... [Pg.153]

The volume integral will give a higher order term in k, so for now, we focus on the surface integral. The displacement due to the phonon is conveniently expanded in terms of the spherical waves e " =... [Pg.201]

This relationship characterizes the mechanical sensitivity of the vertical spring balance, because it shows the change in displacement due to a change in the field and the ratio mjk is the parameter of this sensitivity. It is clear that with an increase of this ratio in principle, we are able to observe smaller changes of the field because the difference A/ becomes larger. This dependence of m and k is almost obvious. For instance, with an increase of mass the gravitational force increases and a greater... [Pg.189]

The curves in Figure 1.20 are stylized the leftward displacement due to the blockade of noradrenaline uptake would not be expected to be exactly parallel. [Pg.50]

ZnS(llO) surface consists of parallel zigzag chains with equal numbers of zinc and sulphur ions (see Fig. 9.12(a)). It is a charge neutral surface. Relaxation of the ZnS (110) surface has been performed using GGA with CASTER Some pioneering works show that there is a negligible displacement of ions below the second and third atomic layer. Therefore, in relaxation calculation, only the atoms on the first layer of the surface are allowed to move. The surface structure and ionic displacement vectors for the (110) surface are shown in Fig. 9.12(b). Ionic displacements due to surface relaxation are presented in Table 9.5. [Pg.232]

Table 9.5 The ZnS (110) surface ionic displacements due to surface relaxation... Table 9.5 The ZnS (110) surface ionic displacements due to surface relaxation...
To separate the effects of static and dynamic disorder, and to obtain an assessment of the height of the potential barrier that is involved in a particular mean-square displacement (here abbreviated (x )), it is necessary to find a parameter whose variation is sensitive to these quantities. Temperature is the obvious choice. A static disorder will be temperature independent, whereas a dynamic disorder will have a temperature dependence related to the shape of the potential well in which the atom moves, and to the height of any barriers it must cross (Frauenfelder et ai, 1979). Simple harmonic thermal vibration decreases linearly with temperature until the Debye temperature Td below To the mean-square displacement due to vibration is temperature independent and has a value characteristic of the zero-point vibrational (x ). The high-temperature portion of a curve of (x ) vs T will therefore extrapolate smoothly to 0 at T = 0 K if the sole or dominant contribution to the measured (x ) is simple harmonic vibration ((x )y). In such a plot the low-temperature limb is expected to have values of (x ) equal to about 0.01 A (Willis and Pryor, 1975). Departures from this behavior indicate more complex motion or static disorder. [Pg.346]

Fig. 15. Data acquired in a multi-block NP experiment (32 T-values). (a) Experiment done with the thermal compensation turned Off. The FID offset is clearly not the same for all blocks, revealing magnetic field displacements due to magnet temperature fluctuations. The magnet temperature varies because the power dissipated on it in each block depends on the varying t value, (b) The same experiment with the thermal compensation turned On. Fig. 15. Data acquired in a multi-block NP experiment (32 T-values). (a) Experiment done with the thermal compensation turned Off. The FID offset is clearly not the same for all blocks, revealing magnetic field displacements due to magnet temperature fluctuations. The magnet temperature varies because the power dissipated on it in each block depends on the varying t value, (b) The same experiment with the thermal compensation turned On.
The mean-square displacements of each of the atoms in the crystal, which affect the the X-ray scattering amplitudes, are obtained by summation over the displacements due to all normal modes, each of which is a function of ea(j Icq), as further discussed in section 2.3. The eigenvalues of D are the frequencies of the normal modes. [Pg.26]

A considerable simplification is achieved when molecules can be treated as rigid bodies, as was done for naphthalene and anthracene (Fig. 2.2), the frequency spectra of which were derived using atom-atom potential functions. The mean-square displacements due to the internal modes can be calculated from the experimental infrared and Raman force constants, and added to the values obtained with Eq. (2.58). The rigid-body model for thermal vibrations is further discussed in section 2.3.3. [Pg.41]

Biirgi generalized the model, assuming a temperature independent high frequency term accounting for displacements due to the internal modes. By means of multi-... [Pg.61]

The key to get a diabatic electronic state is a strict constraint i.e. keep local symmetry elements invariant. For ethylene, let us start from the cis con-former case. The nuclear geometry of the attractor must be on the (y,z)-plane according to Fig.l. The reaction coordinate must be the dis-rotatory displacement. Due to the nature of the LCAO-MO model in quantum computing chemistry, the closed shell filling of the HOMO must change into a closed shell of the LUMO beyond 0=n/4. The symmetry of the diabatic wave function is hence respected. Mutatis mutandis, the trans conformer wave function before n/4 corresponds to a double filling of the LUMO beyond the n/4 point on fills the HOMO twice. At n/4 there is the diradical singlet and triplet base wavefunctions. [Pg.188]

If a mechanical degradation of a solution of two polymers is carried out by high speed stirring, the formation of a block copolymer is not probable as the scission of polymer molecules at low concentration is not caused mainly by intermolecular interaction, such as by collision of molecules and through entanglements, but by displacements due to hydrodynamic forces in velocity gradients. Nakamo and Minoura (98) did obtain reaction by stirring a benzene solution of polyethylene oxide and poly(methyl methacrylate). [Pg.62]

Improved print quality, since there is no pixel displacement due to film distortion... [Pg.28]

Fig. 6.2. Top and side views (in top and bottom sketches of each panel) of adsorption geometries on various metal surfaces. Adsorbates are drawn shaded. Dotted lines represent clean-surface (relaxed) atomic positions arrows show atomic displacements due to adsorption... Fig. 6.2. Top and side views (in top and bottom sketches of each panel) of adsorption geometries on various metal surfaces. Adsorbates are drawn shaded. Dotted lines represent clean-surface (relaxed) atomic positions arrows show atomic displacements due to adsorption...
Already for this reason, the electron-shifts in the C—OH system on inethylation or hydrogen bond formation with ethanol make much smaller contributions to the bathockromic displacements of the K-bands. In addition, the electron-shifts in the benzene ring coincide only partly with the direction of the effective charge migration. Thus, the observed band displacements due to hydrogen bonding (D, H-bond) are only 16-24 A. [Pg.267]

Solution to the nondimensional axisymmetric stagnation-flow problem is plotted in Fig. 6.3. Since the viscous boundary layer merges asymptotically into the inviscid potential flow, there is not a distinct edge of the boundary layer. By convention, the boundary-layer thickness is defined as the point at which the radial velocity comes to 99% of its potential-flow value. From Fig. 6.3 it is apparent that the boundary-layer thickness S is approximately z 2. In addition to the boundary-layer thickness, a displacement thickness can be defined. The displacement thickness is the distance that the potential-flow field appears to be displaced from the surface due to the viscous boundary layer. If there were no viscous boundary layer (i.e., the inviscid flow persisted right to the surface), then the axial velocity profile would have a constant slope du/dz = —2. As shown in Fig. 6.3, projecting the constant axial-velocity slope to the surface obtains an intercept of u = 0 at approximately z = 0.55. Since the inviscid flow would have to come to zero velocity at the surface, z = 0.55 is the distance that the potential flow is displaced due to the viscous boundary layer. Otherwise, the potential flow is unaltered by the boundary layer. [Pg.260]


See other pages where Displacement due is mentioned: [Pg.2828]    [Pg.744]    [Pg.286]    [Pg.207]    [Pg.73]    [Pg.577]    [Pg.960]    [Pg.38]    [Pg.464]    [Pg.527]    [Pg.560]    [Pg.267]    [Pg.50]    [Pg.352]    [Pg.223]    [Pg.235]    [Pg.179]    [Pg.150]    [Pg.44]    [Pg.565]    [Pg.81]    [Pg.219]    [Pg.103]    [Pg.204]    [Pg.84]    [Pg.186]    [Pg.199]   
See also in sourсe #XX -- [ Pg.26 ]




SEARCH



Calculated Stresses due to Sustained Loads and Displacement Strains

© 2024 chempedia.info