Liquids solid-liquid phase transition

This methodology developed to observe water freeze-thaw in concrete materials, may be used quite generally to observe solid-liquid phase transitions in many different materials of industrial and technological interest. The method could be also applied to other problems involving freezing and thawing of water in confined pores. 

The preceding paragraphs illustrate that analogies between point defects in a crystal and solute molecules in a solution have been used previously but in a fairly elementary way. However, the implications of the existence of such analogies in the formulation of the statistical mechanics of interacting defects has not been considered in detail apart from an early paper by Mayer,69 who was interested primarily in the relation of defect interactions, to the solid-liquid phase transition in crystals with short-range forces. The... 

It is not known experimentally whether there is a similar critical point for solid-liquid phase transitions the experimentally available temperatures and pressures are insufficient to resolve this issue. The triple point (which really should be called a triple line) is a triple temperature (Tf) and a triple pressure (Pt) at which the three phases gas, liquid, and solid coexist, but with different volumes this triple line for several compounds is used to define reliable and reproducible standard temperatures for the International Temperature Scale. 

As shown by Eq. (10), Aal is a multiplicative ( normalization ) factor that allows one to relate the experimental quantity Ky to the order parameter S. For each experimental T value listed in your table, calculate An( T) from Eq. (12) and K T) from Eq. (11). Then use your best value for Aal to calculate a value of Sat each experimental T value and plot these 5(7) points versus T. The theoretical power-law curve for 5(7) given by Eq. (8) should also be shown as a hne on this plot. Draw vertical lines at Ti and at P and show how the theoretical curve for 5(7) extrapolates in this region to the value 5 at P. What value of 5 do you get from this curve How do your values of j8, AaKa>, P 7), and 5 compare with those reported for 5CB in Ref. 7 How does the 5(7) curve for a liquid crystal differ from the positional order parameter variation for an ordinary solid-liquid phase transition ... 

Suzuki, T. Franks, F. Solid-liquid phase transitions and amorphous states in ternary sucrose-glycine-water systems. J. Chem. Soc., Faraday Trans. 1993, 89, 3283-3288. 

F2N.C( NF).NF.CFg.NF2 mw 232.04, N 24.14%, FB 0.0% (See preceding entry) colorless Uq, bp 55°, mp below —130°, vap pres 124mm at 10° Prepd by fluorinating cy a noguanidine with nitrogen diluted fluorine and a sodium-magnesium fluoride mixt at 0° Proposed as an oxidizer for proplnts. Extremely expl and especially sensitive when undergoing solid-liquid phase transition. Best handled with a CF Cl slush bath at —130 to —145°. Do not let vapors contact mercuty... 

Solid-Liquid Phase Transition in Alkali-Metal Clusters... 

A form like Eq. (22.1), with A given by Eq. (22.1), ensures large fluctuations in the system because the free-energy cost becomes small as Tapproaches Tc- In the case of the gas-liquid critical point, the density is the order parameter and the term A in Eq. (22.1) above goes to zero as the compressibility diverges. In the ease of the solid-liquid phase transition, the term A does not go to zero and the term B is important. Fluctuations are not too important in the case of a first-order transition, such as liquid-crystal. 

Yu, T.-Q., Chen, P.-Y., Chen, M., Samanta, A., Vanden-Eijnden, E., Tuckerman, M. OtdCT-parametta--aided temperature-accelerated sampling for the exploration of crystal polymorphism and solid-liquid phase transitions. J. Chem. Phys. 140, 214109 (2014)... 

In order to improve the understanding of these systems, Kunieda and coworkers examined the thermotropic behavior of poly(oxyethylene) cholesteryl ethers with different chain lengths, ChFOn, mixed with water at a fixed concentration ( 25 wt%) [32]. This study focused on the different fusion mechanisms that were involved in the solid-liquid phase transition. The soUd-Uquid transition temperature for ChFOn as a function of n is shown in Figure 4.3 (for comparison, the transition temperature for polyethylene glycol is also shown). In both cases, the transition temperature decreased when the chain length was diminished. However, for the cholesterol surfactant, when n < 10, a birefringent phase appeared between... 

With the simplification that the melting temperature is nearly identical with the triple point temperature Ttr and that the heat of fusion Ah is approximately identical with the enthalpy change of the solid-liquid phase transition at the triple point, the following expressions are obtained for the enthalpy and entropy change (steps I-III) for component i ... 

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