Big Chemical Encyclopedia

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

Articles Figures Tables About

Effect on contrast

Temperature variations have minimal effect on contrast and density. [Pg.42]

There was abnormal color perception in 28% of 18 patients taking carbamazepine monotherapy in one case there was an abnormality in the blue-yellow (tritan) axis (22). In the same patients carbamazepine had no effect on contrast sensitivity or glare sensitivity (23). [Pg.629]

The two relevant patient-derived factors that affect contrast enhancement are body weight and cardiac output (or cardiovascular circulation time). All other patient-related effects on contrast attenuation are negligible. [Pg.98]

Figure 10. SIMS images of the distribution of B (bright) and Ni (dark) in polished cross sections of Monel 400 from A and B sources. The imaging field is 150 pin. The grain boundaries of B arc enriched in B. while in A, B is largely found in inclusions in the bulk of the alloy grains. Ni concentration is found to vary. somewhat within certain grains of the alloy. The faces of some grains arc darker than others because of orientation effects on contrast. Figure 10. SIMS images of the distribution of B (bright) and Ni (dark) in polished cross sections of Monel 400 from A and B sources. The imaging field is 150 pin. The grain boundaries of B arc enriched in B. while in A, B is largely found in inclusions in the bulk of the alloy grains. Ni concentration is found to vary. somewhat within certain grains of the alloy. The faces of some grains arc darker than others because of orientation effects on contrast.
Large errors in the low-pressure points often have little effect on phase-equilibrium calculations e.g., when the pressure is a few millitorr, it usually does not matter if we are off by 100 or even 1000%. By contrast, the high-pressure end should be reliable large errors should be avoided when the data are extrapolated beyond the critical temperature. [Pg.140]

As expected, the solvent has a significant effect on the endo-exo selectivity of the uncatalysed Diels-Alder reaction between 1 and 2. In contrast, the corresponding effect on the Lewis-acid catalysed reaction is small. There is no beneficial effect of water on the endo-exo selectivity of the catalysed Diels-Alder reaction. The endo-exo selectivity in water is somewhat diminished relative to that in ethanol and acetonitrile. [Pg.174]

The effects of these ligands on the second-order rate constants for the Cu (ligand) catalysed reaction of Ic with 2 are modest In contrast, the effects on IC2 are more pronounced. The aliphatic Oramino acids induce an approximately two-fold reduction of Iv relative to for the Cu" aquo ion. For the square planar coordinated copper ions this effect is expected on the basis of statistics. The bidentate ligands block half the sites on the copper centre. [Pg.175]

A striking example of an electronic effect on carbonyl group stability and its rela tion to the equilibrium constant for hydration is seen m the case of hexafluoroacetone In contrast to the almost negligible hydration of acetone hexafluoroacetone is completely hydrated... [Pg.714]

Using the case of f = 3 and p = 0.3 as an example, p, = 0.877 when r = 1 in contrast to, say, 0.886 when r = 0.98. This illustrates that failure to maintain stoichiometric balance continues to have a limiting effect on polymerization in this case also. [Pg.320]

In contrast, the addition of LDPE or PS to the mixture had Httie effect on its behavior in the Conrad process. [Pg.232]

Each olefin is more soluble than the paraffin of the same chain length, but the solubiHty of both species declines as chain length increases. Thus, in a broa d-boiling mixture, solubiHties of paraffins and olefins overlap and separation becomes impossible. In contrast, the relative adsorption of olefins and paraffins from the Hquid phase on the adsorbent used commercially for this operation is shown in Figure 2. Not only is there selectivity between an olefin and paraffin of the same chain length, but also chain length has Httie effect on selectivity. Consequentiy, the complete separation of olefins from paraffins becomes possible. [Pg.291]

Standard polyester fibers contain no reactive dye sites. PET fibers are typically dyed by diffusiag dispersed dyestuffs iato the amorphous regions ia the fibers. Copolyesters from a variety of copolymeri2able glycol or diacid comonomers open the fiber stmcture to achieve deep dyeabiHty (7,28—30). This approach is useful when the attendant effects on the copolyester thermal or physical properties are not of concern (31,32). The addition of anionic sites to polyester usiag sodium dimethyl 5-sulfoisophthalate [3965-55-7] has been practiced to make fibers receptive to cationic dyes (33). Yams and fabrics made from mixtures of disperse and cationicaHy dyeable PET show a visual range from subde heather tones to striking contrasts (see Dyes, application and evaluation). [Pg.325]

The incidence of these defects is best determined by high resolution F nmr (111,112) infrared (113) and laser mass spectrometry (114) are alternative methods. Typical commercial polymers show 3—6 mol % defect content. Polymerization methods have a particularly strong effect on the sequence of these defects. In contrast to suspension polymerized PVDF, emulsion polymerized PVDF forms a higher fraction of head-to-head defects that are not followed by tail-to-tail addition (115,116). Crystallinity and other properties of PVDF or copolymers of VDF are influenced by these defect stmctures (117). [Pg.387]

Procedures for the collection of whole blood are similar throughout the world. An interval from at least 8 weeks (United States) to 12 weeks (United Kingdom) is required between a donation of 450 mL blood, which yields about 250 mL plasma. In some countries a smaller volume of blood is collected, eg, 350—400 mL in Italy, Greece, and Turkey and as Httie as 250 mL in some Asian countries (147). Regulations concerning plasmapheresis donations vary more widely across the world eg, up to 300 mL of plasma can be taken in Europe in contrast to 1000 mL in the United States, both on a weekly basis. Consequentiy, both the mode of donation and the country in which it is given can have a profound effect on plasma collection (Table 6). [Pg.531]

More recently, a number of tests of chemical stabihty of the latex concentrate have been developed. Chemical stabihty variance in the raw concentrate has considerable effect on the dipping characteristics of latex compounds, and can also affect mechanical stabihty of the compound. A broad rule is that, while latex MST can be increased or decreased without necessarily affecting its chemical stabihty, any change in the latter always is reflected in the MST. A new test, in which chemical stabihty is deterrnined by measurement of the effect of weak 2inc acetate solution added to a second mechanical stabihty sample and the result contrasted with the original MST, is available to numerically quantify chemical stabihty (56). [Pg.261]

In many places, the need for desalination is even more urgent than the production of food, which is limited by water shortages. These shortages exist both in the petroleum-rich countries and in many of the least-developed and poorest countries of the world. In the case of the former, the improved water supply obtained through desalination has already had stunning effects by contrast, Httie hope for progress is on the horizon for the poor countries. [Pg.240]

Water-insoluble barium salts are poorly absorbed. In fact, barium sulfate is used as a contrast material for x-ray examination of the gastrointestinal tract based on its limited solubility andlow toxicity (52). Barium sulfate fed to mice at various levels up to 8 ppm dietary Ba ( 1.14 mg/kg-d as Ba " ) for three generations had no significant effects on growth, mortality, morbidity, or reproductive performance (53). [Pg.483]


See other pages where Effect on contrast is mentioned: [Pg.459]    [Pg.74]    [Pg.459]    [Pg.74]    [Pg.1638]    [Pg.62]    [Pg.75]    [Pg.151]    [Pg.342]    [Pg.401]    [Pg.202]    [Pg.296]    [Pg.254]    [Pg.110]    [Pg.221]    [Pg.53]    [Pg.204]    [Pg.100]    [Pg.272]    [Pg.445]    [Pg.460]    [Pg.488]    [Pg.488]    [Pg.490]    [Pg.492]    [Pg.498]    [Pg.499]    [Pg.500]    [Pg.309]    [Pg.196]    [Pg.237]    [Pg.348]    [Pg.14]    [Pg.295]   
See also in sourсe #XX -- [ Pg.203 ]




SEARCH



© 2024 chempedia.info