Magnesium , concentrations

COMBINED APPLICATION OF COMPOSITION AND STRUCTURE ANALYSIS METHODS TO THE DETERMINATION OF MAGNESIUM CONCENTRATION AND LOCATION IN BONE... 

Solution Plotting E vs. log[Mg2+] gives a straight line the magnesium concentration (2.6 x 10-4m) corresponding to the 125 mV reading can be read directly from the axis. 

Magnesium concentration in natural waters and ground-water... 

There is some debate about what controls the magnesium concentration in seawater. The main input is rivers. The main removal is by hydrothermal processes (the concentration of Mg in hot vent solutions is essentially zero). First, calculate the residence time of water in the ocean due to (1) river input and (2) hydro-thermal circulation. Second, calculate the residence time of magnesium in seawater with respect to these two processes. Third, draw a sketch to show this box model calculation schematically. You can assume that uncertainties in river input and hydrothermal circulation are 5% and 10%, respectively. What does this tell you about controls on the magnesium concentration Do these calculations support the input/removal balance proposed above Do any questions come to mind Volume of ocean = 1.4 x 10 L River input = 3.2 x lO L/yr Hydrothermal circulation = 1.0 x 10 L/yr Mg concentration in river water = 1.7 X 10 M Mg concentration in seawater = 0.053 M. 

The body s normal daily magnesium requirement is 300 to 350 mg/day to maintain a serum magnesium concentration of 1.5 to 2.4 mg/dL (0.75 to 1.2 mmol/L). Because magnesium is the second most abundant ICF cation, serum concentrations are a relatively poor measure of total body stores. Magnesium catalyzes and/or activates more than 300 enzymes, provides neuromuscular stability, and is involved in myocardial contraction. Magnesium is generally not part of standard chemistry panels, and therefore must be ordered separately.2,37,42 44,45... 

Symptoms are rare when the serum magnesium concentration is less than... 

Klepinger, L.L. (1990). Magnesium ingestion and bone magnesium concentration in paleodietary reconstruction - cautionary evidence from an animal model. Journal of Archaeological Science 17 513-517. 

Figure 2 is a plot of the correction parameter C as a function of magnesium concentration and pH. Note that for the typical range of limestone scrubber inlet liquor pH, 5.2 to... 

Equilibrium S02 Partial Pressure. Figure 3 is a plot of Equation 1 for zero chloride concentration, showing the very strong effect of pH and the relatively weak effect of magnesium concentration on the equilibrium S02 partial pressure, p 02. 

An increase in magnesium concentration from 100 to 1000 m-mole/1 increases pS02 by about a factor of two. Most limestone scrubbing systems with magnesium enhancement would operate midway between these magnesium concentrations, about 200-400 m-mole/1. 

Figure 2. Correction parameter C as a function of magnesium concentration and...

Figure 3. Equilibrium SOi partial pressure as a function of pH and magnesium concentration for liquors saturated with calcium sulfite and gypsum at 50°C with...

Figure 6 presents the strong effects of both pH and magnesium concentration on the equilibrium concentration of dissolved SO2 species, where chloride is absent. The figure is derived from Equations 2, 3, and 5. 

Magnesium concentration = 0-600 m-mole/1 Chloride concentration = 50-500 m-mole/1 Chloride-to-magnesium ratio with magnesia additive = 0.1-1.2 mole/mole Slurry flow rate = 20, 30, or 40 gpm/ft ... 

In the absence of chloride, these sulfite concentrations of 1.2, 10, and 16 m-mole/1 are achieved for dissolved magnesium concentrations of zero, 250, and 450 m-mole/1, respectively (see Figure 4). 

For liquors saturated with both calcium sulfite and gypsum, the concentration of dissolved sulfite species increases linearly with dissolved magnesium concentration, decreases linearly with dissolved chloride concentration, and is only weakly affected by pH. 

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