Single salt interval

From what has been said, it is evident that when the formation of a double salt can occur, three temperature intervals can be distinguished, viz. the single-salt interval, the transition interval, and the double-salt interval. When the temperature lies in the first interval, evaporation leads first of all to the crystallisation of one of the single salts, and then to the separation of both the single salts together. In the second temperature interval, evaporation again leads, in the first place, to the deposition of one of the single salts, and afterwards to the crystallisation of the double salt. In the third temperature interval, only the double salt crystallises out. This will become clearer from what follows. 

Transition Interval,—Fig. 115 will also render intelligible a point of great importance in connection with astracanite, and with double salts generally. At temperatures between those represented by the points B and X, the double salt when brought in contact with water will be decomposed with separation of sodium sulphate. Above the temperature of the point X, however, the solution of the pure double salt is stable, because it can still take up a little of either of the components. At temperatures, then, above that at which the solution in contact with the double salt and the less soluble single salt, contains the single salts in the ratio in which they are present in the double salt,... 

Summary.— With regard to double salts we have learned that their formation from and their decomposition into the single salts is connected with a definite temperature, the transition temperature. At this transition temperature two vapour pressure curves cut, viz. a curve of dehydration of a mixture of the single salts and the solubility curve of the double salt or the dehydration curve of the double salt and the solubility curve of the mixed single salts. The solubility curves, also, of these two systems intersect at the transition point, but although the formation of the double salt commences at the transition point, complete stability in contact with water may not be attained till some temperature above (or below) that point. Only when ike temperature is beyond the transition interval will a double salt dissolve in water without decomposition (e.g. the alums). 

Lastly, if the temperature lies outside the transition interval, isothermal evaporation of an unsaturated solution of the composition X (Fig. 127) will lead to the deposition of pure double salt from beginning to end. If a solution of the composition Y is evaporated, the component A will first be deposited and the composition of the solution will alter in the direction of E, at which point double salt will separate out. Since the solution at this point contains relatively more of A than is present in the double salt, both the double salt and the single salt A will be deposited on continued evaporation, in order that the composition of the solution shall remain unchanged. In the case of solution Z, first component B and afterwards the double salt will be deposited. The result will, therefore, be a mixture of double salt and the salt B (congruently saturated solutions). 

The temperature range for equilibria in PHRQPITZ is variable and is generally 0 -60 °C if AH/ is known. However, the NaCl system is valid to approximately 350 C. The temperature dependence of the solubility of many of the minerals in PHRQPITZ is not known and large errors could result if calculations are made at temperatures other than 25 for these solids. Limited temperature-dependent data for single salt parameters are included, but are probably not valid outside the interval 0 to 60 °C. 

Trains of action potentials recorded extracellularly from a neuron in the rostral portion of the nucleus of the solitary tract (NST) of a rat. About 10s of activity is shown for each stimulus, the application of which is indicated by the arrowheads. This cell did not respond to the sweet-tasting stimuli (sucrose and fructose), but showed robust responses to sodium salts, nonsodium salts, acids, and all the 10 bitter stimuli applied to the tongue and palate. Arrowheads indicated the time of stimulus application. The interspike interval histogram shown at the lower left indicates that no spikes fell within the neuron s refractory period, demonstrating that the spikes are recorded from a single neuron. Data from Lemon and Smith (2005)... 

Fig. 21. Historical increase in the flux of excess Cu to the salt marsh compared to the trend in U.S. primary copper production over the same interval. Both trends are normalized by dividing the rate at any time by the 1970 rate. In the case of the salt marsh, the flux is averaged over several years accumulation, while the primary-production figures represent the rate for a single year, arbitrarily taken at the beginning of every decade from 1850-1970 (U.S. Dept. Interior, 1973).

The fate of RF-RNA in . coli was studied by fractionation of the isolated RNA by LiCl precipitation. RF-RNA is soluble in solutions of 1.0 and 1.5 M LiCl. Single-stranded RNA and double-stranded RNA with attached single-stranded RNA (RI-RNA) precipitate in 1.5 M LiCl at —12° C. More label was found in the LiCl-soluble fraction in cell samples which were incubated for longer time intervals after exposure to RF-RNA. The amount of labeled RF-RNA converted from a salt-soluble to an insoluble RNA in a given time interval varied from experiment to experiment, dep nding on the amount of input RNA (Koch and Vollertsen, unpublished). With small amounts of RF-RNA (less than 1 (xg/g of cells) 50% of the RF-RNA label was found in a LiCl-sedimentable form. With more RF-RNA (30 (xg/g of cells), the ratio of input counts in LiCl supernatant fluid to LiCl sediment was 9.2 1 at 20 min and 4.6 1 at 120 min (Table 11). 

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