Potassium heat production

Wasserburg G. J., MacDonald E., Hoyle E., and Eowler W. A. (1964) Relative contributions of uranium, thorium, and potassium to heat production in the Earth. Science 143, 465 -467. 

As a possible radiogenic heat source in the Earth, the presence of an appreciable amount of potassium in the core was suggested over 30 years ago (Lewis, 1971 Hall and Murthy, 1971). The estimated concentration of potassium in the mantle is 240 ppm (McDonough and Sun, 1995). If the concentration of potassium in the core is at a comparable level, the present-day heat production due to would be on the order of 10 W, enough to drive the geodynamo. Radiogenic heat production due to also has direct implications for convection in the outer core, heat flux at the CMB, and the dynamics of the lower mantle. Recent studies of plume dynamics and considerations of the age of the inner core have inspired a renewed interest in the potassium content of the core (Murthy et ai, 2003, and references therein see Chapter 2.15). 

Heat Production Rate due to Uranium, Thorium, and Potassium... 

For ease of comparison with heat flow data, we shall not discuss in detail the concentration of uranium, thorium, and potassium in crustal rocks and shall refer instead to the heat production rate. Table 1 lists the key characteristics of the main radiogenic isotopes U, U, Th, and as well as their heat production rates (from Rybach, 1988). Using present-day isotopic ratios, the bulk heat production of a rock sample is calculated (in Wkg ) by summing the contributions of each element as follows ... 

Heier K. S. and Lambert 1. B. (1978) A Compilation of Potassium, Uranium and Thorium Abundances and Heat Production of Australian Rocks. Technical Report, Research School of Earth Science, Australian National University, Canberra. 

Because in most physiological circumstances oxygen consumption is controlled by energy metabolism, Ismail-Beigi and Edelman (22) proposed that the primary effect of thyroid hormones is to increase the amount of energy expended in translocating cations across cell membranes, probably as a response to an increased passive leak of sodium into, and potassium out of, cells. The extent to which this transport contributes to heat production and ATP utilization is uncertain. The stimulation of futile cycles by thyroid hormones (23) has been suggested to be an additional component of ATP disposal. 

Usually the radiogenic heat production rate is calculated from the potassium, uranium and thorium content and the rock density using the formula by Rybach (1976) and Rybach and Cermak (1982) ... 

In most igneous rocks, uranium and thorium contribute in a comparable amount, whereas potassium always contributes a substantially smaller amotmt to total heat production, in proportions of approximately 40% (U) 45% (Th) and 15% (K) (Rybach and Cermak, 1982). Table 5.10 gives some data. 

The activity of the Na+-K+ pump has been proposed to be regulated by thyroid hormones and to account for a large contribution of the increased energy expenditure in hyperthyroidism. Microcalorimetry was used to measure erythrocyte [64] and lymphocyte [62 heat production rate during ouabain-induced inhibition of ATPasc, thus estimating the importance of the sodium-potassium pump in hyperthyroidism. The results of these studies show that the raised heat production rate in this condition was not due to increased energy expenditure by the pump. This was confirmed in microcalorimetric studies with mammalian. skeletal muscle [65,66] and hcpatocytes [66,67J. 

Heat production rate in human resting muscle was measured in a perfusion microcalorimeter during 2 h, then ouabain octahydrate was introduced into the calorimetric ampoule at an optimal concentration to obtain maximal inhibition of the Na -K " pump. The decrease of heat production reflected the amount of energy consumed by the pump. From the same muscle specimen, samples were taken for determination of potassium and magnesium concentration. The energy expenditure of the pump was found to correlate positively with muscle potassium and magnesium [76]. 

The product is a solid yellow hydrated oxide. If prepared by a method in the absence of water, a black anhydrous product is obtained. Germanium(II) oxide is stable in air at room temperature but is readily oxidised when heated in air or when treated at room temperature with, for example, nitric acid, hydrogen peroxide, or potassium manganate(VII). When heated in the absence of air it disproportionates at 800 K ... 

Unexpectedly we find that the bromate(V) ion in acid solution (i.e. effectively bromic(V) acid) is a more powerful oxidising agent than the chlorate(V) ion, CIO3. The halates(V) are thermally unstable and can evolve oxygen as one of the decomposition products. Potassium chlorate(V), when heated, first melts, then resolidifies due to the formation of potassium chlorate(VII) (perchlorate) ... 

Prepare a mixture of 30 ml, of aniline, 8 g. of o-chloro-benzoic acid, 8 g. of anhydrous potassium carbonate and 0 4 g. of copper oxide in a 500 ml. round-bottomed flask fitted with an air-condenser, and then boil the mixture under reflux for 1 5 hours the mixture tends to foam during the earlier part of the heating owing to the evolution of carbon dioxide, and hence the large flask is used. When the heating has been completed, fit the flask with a steam-distillation head, and stcam-distil the crude product until all the excess of aniline has been removed. The residual solution now contains the potassium. V-phenylanthrani-late add ca. 2 g. of animal charcoal to this solution, boil for about 5 minutes, and filter hot. Add dilute hydrochloric acid (1 1 by volume) to the filtrate until no further precipitation occurs, and then cool in ice-water with stirring. Filter otT the. V-phcnylanthranilic acid at the pump, wash with water, drain and dry. Yield, 9-9 5 g. I he acid may be recrystallised from aqueous ethanol, or methylated spirit, with addition of charcoal if necessary, and is obtained as colourless crystals, m.p. 185-186°. 

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