Titanic effect

Tetraalkyl titanates are the most commonly used catalysts for PBT polymerization [8], The varieties of titanates include tetraisopropyl titanate (TPT), tetrabutyl titanate (TBT) and tetra(2-ethylhexyl) titanate (TOT). Titanates effectively speed the reaction rate with few detrimental effects on the resin. Alkoxy zirconium and tin compounds, as well as other metal alkoxides, may also be used in PBT polymerization. 

Watt defined a related phenomenon he called the Titanic effect to explain the fact that major accidents are often preceded by a belief that they cannot happen. The Titanic effect says that the magnitude of disasters decreases to the extent that people beheve that disasters are possible and plan to prevent them or to minimize their effects [204]. 

Watt, Kenneth E.F. 1974. The Titanic Effect. Stamford, CT Sinauer Associates... 

The Six Functions of the Titanate Molecule 105 Table 5.6 Titanate effects in CaC03-filled polyolefins. 

Certain glass-ceramic materials also exhibit potentially useful electro-optic effects. These include glasses with microcrystaUites of Cd-sulfoselenides, which show a strong nonlinear response to an electric field (9), as well as glass-ceramics based on ferroelectric perovskite crystals such as niobates, titanates, or zkconates (10—12). Such crystals permit electric control of scattering and other optical properties. 

Numerous modifications of chromium-based catalysts have been made through the introduction of various additives, the most effective of which are titanium alkoxides (38,39). These additives apparentiy reduce surface silyl chromate moieties to chromium titanates, which are then oxidized to titanyl chromates. These catalysts offer a better control of the resin molecular weight (39). 

Mixtures of a titanium complex of saturated diols, such as TYZOR OGT, and a titanium acylate, such as bis- -butyl-bis-caproic acid titanate, do not have a yellowing or discoloring effect on white inks used to print polyolefin surfaces (506). The complexes formed by the reaction of one or two moles of diethyl citrate with TYZOR TPT have an insignificant color on their own and do not generate color with phenol-based antioxidants (507). The complexes formed by the addition of a mixture of mono- and dialkyl phosphate esters to TYZOR TBT are also low color-generating, adhesion-promoting additives for use in printing polyolefin films (508). 

Fig. 1. Effect of compositional variations on the dielectric properties of strontium titanate-barium titanate solid solutions. A, BaQ SrQ QTiO B,...

The contribution to the stress from electromechanical coupling is readily estimated from the constitutive relation [Eq. (4.2)]. Under conditions of uniaxial strain and field, and for an open circuit, we find that the elastic stiffness is increased by the multiplying factor (1 -i- K ) where the square of the electromechanical coupling factor for uniaxial strain, is a measure of the stiffening effect of the electric field. Values of for various materials are for x-cut quartz, 0.0008, for z-cut lithium niobate, 0.055 for y-cut lithium niobate, 0.074 for barium titanate ceramic, 0.5 and for PZT-5H ceramic, 0.75. These examples show that electromechanical coupling effects can be expected to vary from barely detectable to quite substantial. 

The reader should note tliat since many risk assessments have been conducted on the basis of fatal effects, there are also uncertainties on precisely what constitutes a fatal dose of thennal radiation, blast effect, or a toxic chemical. Where it is desired to estimate injuries as well as fatalities, tlie consequence calculation can be repeated using lower intensities of exposure leading to injury rather titan dcatli. In addition, if the adverse healtli effect (e.g. associated with a chemical release) is delayed, the cause may not be obvious. Tliis applies to both chronic and acute emissions and exposures. 

These alkoxides are liquids or sublimable solids and, unless the steric effects of the alkyl chain prevent it, apparently attain octahedral coordination of the titanium by polymerization (Fig. 21.6). The lower alkoxides are especially sensitive to moisture, hydrolysing to the dioxide. Application of these organic titanates (as they are frequently described) can therefore give a... 

Since discovering and making use of the piezoelectric effect in naturally occurring crystals such as quartz and Rochelle salts, scientists have produced a wide range of piezoelectric materials in the laboratoi y. An early example is barium titanate, used in an electrical component called a capacitor. Currently, most piezoelectric materials are oxide materials based on lead oxide, zirconate oxide, and titanium. These very hard piezoelectric materials are termed piezoceramics. 

Sychev, M. M., Medvedeva, I. N., Biokov, V. A. Krylov, O. S. (1982). Effect of reaction kinetics and morphology of neoformation on the properties of phosphate cements based on magnesium titanates. Chemical Abstracts, 96, 222252e. 

Hydroxylation of benzene with hydrogen peroxide in the presence of solid zeolite catalyst (titan-silicate-zeolite) was chosen by Radoiu et al. [57] as a model heterogeneous liquid-phase reaction for study of microwave effects, Scheme 10.12. 

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