Griffiths temperature

While, in principle, a tricritical point is one where three phases simultaneously coalesce into one, that is not what would be observed in the laboratory if the temperature of a closed system is increased along a path that passes exactly tlirough a tricritical point. Although such a difficult experiment is yet to be perfomied, it is clear from theory (Kaufman and Griffiths 1982, Pegg et al 1990) and from experiments in the vicinity of tricritical points that below the tricritical temperature only two phases coexist and that the volume of one slirinks precipitously to zero at T. ... 

Non-isothermal measurements of the temperatures of dehydrations and decompositions of some 25 oxalates in oxygen or in nitrogen atmospheres have been reported by Dollimore and Griffiths [39]. Shkarin et al. [606] conclude, from the similarities they found in the kinetics of dehydration of Ni, Mn, Co, Fe, Mg, Ca and Th hydrated oxalates (first-order reactions and all values of E 100 kJ mole-1), that the mechanisms of reactions of the seven salts are probably identical. We believe, however, that this conclusion is premature when considered with reference to more recent observations for NiC204 2 H20 (see below [129]) where kinetic characteristics are shown to be sensitive to prevailing conditions. The dehydration of MnC204 2 H20 [607] has been found to obey the contracting volume... 

Han and Griffith (1965a) developed a modified version of an ebullition cycle and, using a simplification in the temperature profile equation, they obtained an explicit form for the waiting period ... 

Hsu and Graham (1961) took into consideration the bubble shape and incorporated the thermal boundary-layer thickness, 8, into their equation, thus making the bubble growth rate a function of 8. Han and Griffith (1965b) took an approach similar to that of Hsu and Graham with more elaboration, and dealt with the constant-wall-temperature case. Their equation is... 

The etherdiacrylate 6 was prepared by a modification of the procedure of Griffith and O Rear.11 To a solution of etherdiol (3 g, 3.78 mmol) in Freon 113 (10ml) in an ice-water bath under nitrogen, triethylamine (0.791 g, 7.81 mmol) in Freon 113 (5 ml) was added dropwise in 10 min. After 10 min more, acryloyl chloride (0.707g, 7.81 mmol) in Freon 113 (5 ml) was added dropwise in 20min a precipitate formed immediately. After stirring for 2 h at room temperature, filtration through Celite to remove the solid, followed by evaporation at room temperature in vacuo, 3.02 g of a viscous liquid was obtained. 

With the development of modern computation techniques, more and more numerical simulations occur in the literature to predict the velocity profiles, pressure distribution, and the temperature distribution inside the extruder. Rotem and Shinnar [31] obtained numerical solutions for one-dimensional isothermal power law fluid flows. Griffith [25], Zamodits and Pearson [32], and Fenner [26] derived numerical solutions for two-dimensional fully developed, nonisothermal, and non-Newtonian flow in an infinitely wide rectangular screw channel. Karwe and Jaluria [33] completed a numerical solution for non-Newtonian fluids in a curved channel. The characteristic curves of the screw and residence time distributions were obtained. 

Mettler and colleagues reported an alternative synthesis of malonate 16 in the same paper (Griffiths et al., 1991) in which they condensed cyclohexanone with ethyl cyano-acetate instead of diethyl malonate in the Knoevenagel reaction to give ethyl cyano(cyclohexylidene)-acetate (18). In the presence of a catalytic amount of sodium cyanide, the Michael addition of HCN to cyanoacetate 18 proceeded in good yield at room temperature to generate the dicyanoester 19. Intermediate 19 was selectively converted to malonate 16 with pressurized HCI treatment in ethanol (Scheme 16.4). 

Griffiths, D. W., Bain, H., Dale, M. F. (1997). The Effeet of Low-Temperature Storage on the Glyeoalkaloid Content of Potato (Solanum tuberosum) Tubers. Journal of Science of food and Agriculture, 74(3), 301-307. 

A number of mediods have been developed for measuring the heat of vaporization, In die Awberg and Griffith s method, the flow is continuous the heat of evaporation of the liquid under investigation is transmitted to a stream of water flowing at constant rate and its increase in temperature is measured. 

Acetonitrile, acetone, ethanol, and methanol have been used to extract isoflavones from soy foods. Among them, acetonitrile proved to be the most efficient (Griffith et al., 2001 Murphy et al., 2002). The solvent is supplemented with 0.1 M HC1 to completely un ionize the isoflavones and to release them from protein complexes by denaturing and precipitating the proteins. Room temperature is recommended for extraction to avoid alteration of the natural forms of the isoflavones. The time for extraction, 2 hr, was chosen for maximum recovery and shortest processing time. Ultrasound is used to aid the extraction process by degrading and weakening the cellular matrix. 

Gunthard 7°) on the low-temperature infra-red spectra of silicates with the olivine Mg2Si04 structure (see also Tarte 71>72>) which also includes a normal-coordinate analyses. Tarte 73>, also published an excellent paper on the structures of the aluminates containing the A104-tetrahedra (see also Carrerra et al. 74> for IR and Raman spectra of Al(OH)4 ions), and Griffith 7S> analysed silicate spectra. 

Griffiths et al. (9) have compared the signal to noise ratios of interferometers and monochrometers under the assumption that the source temperature and resolution for both types of instrument are equivalent. Their analysis involves a comparison of the factors appearing in equation 8 and a representation of the advantage of an interferometer over a monochrometer as the ratio of the factors associated with each instrument. A summary of Griffith et al. s (9) analysis is presented in the balance of this section. 

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