Volume stability

When the pit volume stabilizes, there is equilibrium in the annulus and the kick fluid is out of the hole. 

Amplitudes of frontier orbitals are important for regioseletivities of organic reactions (Sect. 3.4 in the Chapter Elements of a Chemical Orbital Theory by Inagaki in this volume). Stabilization by the frontier orbital interaction is greatest when it occurs... 

Specific gravity and adsorption Unit weight Volume stability Deleterious components... 

Forsterite Refractories. Refractories made from forsterite, Mg2Si04, resist alkali attack and have good volume stability, high temperature strength, and fair resistance to basic slags. Uses include nonferrous metal furnace roofs and glass-tank refractories not in contact with the melt, ie, checkers, ports, and uptakes. 

Foam volume stability Change in foam volume with time Stability is often expressed as half-life of the loam. The half-life is defined as the time for half the liquid to drain or half the foam to collapse. 

The ability of a substance to act as a hydraulic cement depends on two groups of factors. First, it must react with water to a sufficient extent and at a sufficient rate y-CjS, which is virtually inert at ordinary temperatures, has no cementing ability. Second, assuming that an appropriate ratio of water to cement is used, the reaction must yield solid products of very low solubility and with a microstructure that gives rise to the requisite mechanical strength, volume stability, and other necessary properties. CjA reacts rapidly and completely with water, but the products that are formed when... 

Direct-bonded magnesia-chrome ore materials exhibit a high strength at high temperatures, superior resistance to slags and volume stability up to 1800 C. They also show a much lower tendency to expansion and subsequent spalling as a result of interaction with iron oxides (cf. the follow ing section on chromite materials). Direct--bonded ware finds application in open-hearth furnaces, in electric arc furnaces, in secondary steelmaking processes, in rotary cement kilns, etc. 

Figures 13.30a and b shows the results of an 0.25 min and Imin gel time, respectively. Both these gel times are relatively short, but the difference in results is striking. Although dilution losses are almost negligible based on the measured relationship between the grout volume injected and the total volume stabilized, the displacement that occurred with slower gelation would make it extremely difficult to erect an effective cutoff curtain. Of importance also is the fact that at the somewhat longer gel time, all the material placed in the coarsest sand was completely washed away by groundwater flow.

A recently developed model to explain this intermittency observed in the population fluctuation assumes a bistable potential whose two minima are the HDL and LDL [12]. By definition, these two forms differ by their specific volumes HDL has relatively lower specific volume than LDL. Now, natural total volume fluctuations of the system at ambient pressure modify the underlying bistable potential as a larger volume stabilizes the LDL state and vice versa. If one assumes that volume fluctuation is periodic in nature, then the effective potential of the system also modulates periodically with the same frequency as volume fluctuation. 

The hmit of MgO content is linked to the lack of respective standardised test of potential expansion, caused by the periclase from clinker. In ASTM standards the method of volume stability testing in autoclave was introduced, and after the United States also nine coimtries have adopted this method, among others Canada, Finland, Belgium and Argentine [27],... 

Hawkins, P., and Hayden, K.L., "The Effect of Free MgO in Clinker on Volume Stability," Cement Chemists Seminar, Portland Cement Association, Skokie, Illinois, 1976,21 pp. 

Ali, M.M., and Mullick, A.K. (1998) Volume stabilization of highMgO cement effect of curing conditions and fly ash addition. Cement and Concrete Research 28,1585-1594. 

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