Dependence on temperature and

As succeeding panels are laid-up, a stack of panels is formed. If the panels are to be cold-pressed, an uncommon procedure in modern manufacturing, the stack will be high enough to fit into the cold-press. The stack is roUed into the press, the press is closed under hydraulic pressure and the bonding pressure, 1035—1205 (ca 150—175 psi) is maintained for the time requited to form a bond. This time could vary from 30 to 120 minutes, depending on temperature and the adhesive formulation used. 

The extent of the initial hydrolysis depends on temperature and how the water is added. Hydrolysis is reduced at slower addition rates and lower temperatures. The hydrolysis subsequent to the initial fast reaction is slow, presumably because part of the acid is converted to fluorosulfate ions which hydrolyze slowly even at elevated temperatures. The hydrolysis in basic solution has also been studied (17). Under controlled conditions, hydrates of HSO F containing one, two, and four molecules of water have been observed (18,19). 

Sihcon nitride can be heated ia air up to 1450—1550°C. In nitrogen, inert gas, or reducing atmosphere, Si N can be heated up to 1750°C. Above 1750°C, decomposition and sublimating evaporation become severe. When in the presence of carbon, however, Si N stabiUty depends on temperature and pressure. The equiUbrium temperature for the reaction... 

Iron, cobalt, and nickel catalyze this reaction. The rate depends on temperature and sodium concentration. At —33.5°C, 0.251 kg sodium is soluble in 1 kg ammonia. Concentrated solutions of sodium in ammonia separate into two Hquid phases when cooled below the consolute temperature of —41.6°C. The compositions of the phases depend on the temperature. At the peak of the conjugate solutions curve, the composition is 4.15 atom % sodium. The density decreases with increasing concentration of sodium. Thus, in the two-phase region the dilute bottom phase, low in sodium concentration, has a deep-blue color the light top phase, high in sodium concentration, has a metallic bronze appearance (9—13). 

Polarimetry. Polarimetry, or polarization, is defined as the measure of the optical rotation of the plane of polarized light as it passes through a solution. Specific rotation [ a] is expressed as [cr] = OcjIc where (X is the direct or observed rotation, /is the length in dm of the tube containing the solution, and c is the concentration in g/mL. Specific rotation depends on temperature and wavelength of measurement, and is a characteristic of each sugar it may be used for identification (7). 

Higher virial coefficients are defined analogously. AH virial coefficients depend on temperature and composition only. The pressure series and density series coefficients are related to one another ... 

The virial equations are unsuitable forhquids and dense gases. The simplest expressions appropriate (in principle) for such fluids are equations cubic in molar volume. These equations, inspired by the van der Waals equation of state, may be represented by the following general formula, where parameters b, 9 5, S, and Tj each can depend on temperature and composition ... 

Diethylcarbama2ine [98-89-1/ is a pipera2ine derivative which is given daily as a prophylactic for canine heartworm disease Dirofilaria immitis) or as a therapeutic for roundworms. D. immitis is transmitted only by mosquitoes, and therefore the period of administration varies geographically, depending on temperatures and humidity which regulate the mosquito life cycle. 

The concentration of dissolved ionic substances can be roughly estimated by multiplying the specific conductance by an empirical factor of 0.55—0.9, depending on temperature and soluble components. Since specific conductance is temperature dependent, all samples should be measured at the same temperature. Alternatively, an appropriate temperature-correction factor obtained by comparisons with known concentrations of potassium chloride may be used. Instmments are available that automatically correct conductance measurements for different temperatures. 

The composition of the products of reactions involving intermediates formed by metaHation depends on whether the measured composition results from kinetic control or from thermodynamic control. Thus the addition of diborane to 2-butene initially yields tri-j iAbutylboraneTri-j -butylborane. If heated and allowed to react further, this product isomerizes about 93% to the tributylborane, the product initially obtained from 1-butene (15). Similar effects are observed during hydroformylation reactions however, interpretation is more compHcated because the relative rates of isomerization and of carbonylation of the reaction intermediate depend on temperature and on hydrogen and carbon monoxide pressures (16). 

The density-series virial coefficients B, C, D,. . . , depend on temperature and composition only. The composition dependencies are given by the exact recipes... 

V-b) V"- + 6V+e) where parameters b, 0, 8, , and T can each depend on temperature and composition. Special cases are obtained by specification of values or expressions for the various parameters. 

The previous definitions can be interpreted in terms of ionic-species diffusivities and conductivities. The latter are easily measured and depend on temperature and composition. For example, the equivalent conductance A is commonly tabulated in chemistry handbooks as the limiting (infinite dilution) conductance and at standard concentrations, typically at 25°C. A = 1000 K/C = ) + ) = +... 

Compressibility of Natural Gas All gases deviate from the perfect gas law at some combinations of temperature and pressure, the extent depending on the gas. This behavior is described by a dimensionless compressibility factor Z that corrects the perfect gas law for real-gas behavior, FV = ZRT. Any consistent units may be used. Z is unity for an ideal gas, but for a real gas, Z has values ranging from less than 1 to greater than 1, depending on temperature and pressure. The compressibihty faclor is described further in Secs. 2 and 4 of this handbook. 

This method of writing D emphasises its exponential dependence on temperature, and gives a conveniently sized activation energy (expressed per mole of diffusing atoms rather than per atom). Thinking again of creep, the thing about eqn. (18.12) is that the exponential dependence of D on temperature has exactly the same form as the dependence of on temperature that we seek to explain. 

But its long-term strength can be a problem. Depending on temperature and environment, the cement may deteriorate suddenly and without warning by "conversion" of... 

Trees and soils of forests act as sources of NH3 and oxides of nitrogen. Ammonia is formed in the soil by several types of bacteria and fungi. The volatilization of ammonia and its subsequent release to the atmosphere are dependent on temperature and the pH of the soil. Fertilizers are used as a tool in forest management. The volatilization of applied fertilizers may become a source of ammonia to the atmosphere, especially from the use of urea. 

In effect this equation indicates that the deformation can be critically dependent on temperature, and that the material will change from a rubbery to a glass-like... 

The melt viscosity is also strongly dependent on temperature and molecular weight. The equation... 

The specific heat of polystyrene is dependent on temperature and at 200°C the value is approximately double that at room temperature." ... 

With most homopolymers and copolymers the apparent viscosity is less dependent on temperature and shear stress (up to 10 dyn/cm ) than that of the polyolefins, thus simplifying die design. On the other hand the melt has a low elasticity and strength and this requires that extruded sections be... 

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