Cycling rates

The number of cycles that is attainable is also a function of the chromatographic peak width - the narrower the peak, then the faster the cycle rate required to define that peak accurately. The peak widths encountered in HPLC, which are relatively wide compared to GC, are such that a compromise between scan speed and sensitivity is less likely to be required. 

As discussed in sections 1.5.3, 2.3 and 2.4.1, the hydrothermal solutions both from back-arc basins and midoceanic ridges are dominantly of seawater origin. Therefore, the fluxes of hydrothermal solution are estimated from seawater cycling rate. This rate is considered to be equal to oceanic production rate times seawater/rock ratio. Kaiho and Saito (1994) estimated the crustal production rate at back-arc basins (Okinawa, Mariana, Andaman, Manus, Woodlark, North Fiji, Lau-Havre, East Scotia and Cayman) based on the spreading rate, thickness of crust and length of ridge axis. Their estimated oceanic crustal production rate is 8.5 x 10 km /m.y. which is roughly equal to 2.5 x lO g/m.y. 

If we accept 5-20 for the seawater/rock ratio, we can calculate the seawater cycling rate at midoceanic ridges as (0.8-4.6) x lO g/year. This value is consistent... 

Hg concentration in hydrothermal solution from back-arc basins and midoceanic ridges has not been determined. Experimental study on graywacke-water interaction suggests that the hydrothermal solution interacted with graywacke contains n x 10 ppm Hg (Bischoff et al., 1981). Cinnabar and metacinnabar are not common but were reported from several Kuroko deposits (Urabe, 1974). From the solubility data on cinnabar and metacinnabar (Barnes and Czamanske, 1967), we can place a limit on the Hg concentration of ore fluids to be n x 10 ppm. Using n x 10 ppm concentration and seawater cycling rate at back-arc basins, hydrothermal Hg flux from back-arc... 

The Mn concentration of hydrothermal solution from back-arc basins varies widely from 12 p.mol/kg-H20 to 7100 p mol/kg H20 (Lau Basin, North Fiji Basin) (Gamo, 1995). But, it ranges mostly from 10 p.mol/kg -H20 to 300 xmol/kg H2O. Using this range and seawater cycling rate (= (0.08-0.8) x 10 g/year), we obtain Mn flux as (0.08-2.4) X 10 mol/year. 

Ba concentration of hydrothermal solution from back-arc basins ranges from 5.3 p.mol/kg-H20 (North Fiji Basin) to 100 p.mol/kg-H20 (Izu-Bonin Suiyo SM) (Gamo, 1995). Assuming that Ba concentration is (20-60) p.mol/kg H2O and seawater cycling rate is 1.8 x 10 g/year, we obtain Ba flux as (3-66) x 10 mol/year. This is greater than or comparable to that of midoceanic ridge flux (2.4-13 x 10 mol/year) (Elderfield and Schultz, 1996) and is comparable to or greater than that of riverine Ba flux (1 x 10 mol/year) (Elderfield and Schultz, 1996). 

Mumane RJ, Cochran JK, Sarmiento JL (1994) Estimates of particle- and thorium-cycling rates in the northwest Atlantic Ocean. J Geophys Res 99 3373-3392 Mumane RJ, Cocliran JK, Buesseler KO, Bacon MP (1996) Least-squares estimates of thorium, particle and nutrient cycling rate constants from the JGOFS North Atlantic Bloom Experiment. Deep-Sea Res 1 43(2) 239-258... 

The design of the 2-electrode electrochemical cells used in this work is state of the art and is based on HS Test Cell available from Hohsen Corp. of Tokyo, Japan [10]. Unless stated otherwise, these cells were tested at 32°C at different cycling rates (from C/20 to C rate) under continuous current. The electrolyte used was EC DMC (1 1), LiPF6 (1M) made by Cheil Industries, South Korea. 

Above t = 60 minutes, changes in the time-average cycling rate at an amplitude of 0.24 were too small to be significant. At the other end of the frequency spectrum, a different timer would have been required to achieve periods less than 1 minute. Periods of less than 1 minute were not investigated furthermore because at shorter periods the square wave becomes increasingly distorted by mixing in the system. 

Fig. 11.3 Electrochemical performance of CNFs CNTs. (a) Galvanostatic discharge/charge (Li inser-tion/extraction, voltage decrease/increase) curves of CNFs CNTs at a cycling rate of C/5 in 1M LiPF6 in 1 1 (v/v) ethylene carbonate (EC)/dimethyl carbonate (DMC) (b) comparison of the electrochemical performance of pristine CNTs and CNFs CNTs in 1M LiPF6 in EC/DMC solution (reprinted with permission from [25]).

Volpe C, Wahlen M, Spivack AJ (1998) Chlorine isotopic composition of marine aerosols Implications for the release of reactive chlorine and HCl cycling rates. Geophys Res Lett 25(20) 3831-3834 Volpe CM (1998) Stable Chlorine Isotope Variations in the Atmosphere. PhD Dissertation, University of California, San Diego, San Diego, California... 

The global hydrological cycle. Rates are In units of km /y and reservoir volumes In km . Note that global estimates of rates and reservoirs are still a matter of uncertainty leading to the ranges reported In the figure. Sources-. (1) Gleick, P. M. (1993). Water in Crisis. Oxford University Press, p. 14. 

A more detailed depiction of the oceanic carbon cycle is presented in Figure 25.2, in which internal cycling rates in the coastal and open ocean are shown. The ocean... 

Determine the pressure and temperature of each state, power required by the top-cycle compressor, power produced by the top-cycle turbines, thermal efficiency of the combined cycle, thermal efficiency of the top cycle, thermal efficiency of the bottom cycle, power input to the combined cycle, power output by the combined cycle, power net output of the combined cycle, rate of heat added to the combined cycle, rate of heat removed from the combined cycle, power input to the top cycle, power output by the top cycle, power net output of the top cycle, rate of heat added to the top cycle, rate of heat removed from the top cycle, power input to the bottom cycle, power output by the bottom cycle, power net output of the bottom cycle, rate of heat added to the bottom cycle, and rate of heat removed from the bottom cycle. 

Determine the mass flow rate of the freon cycle, thermal efficiency of the combined cycle, power input to the combined cycle, power output by the combined cycle, power net output of the combined cycle, rate of heat added to the combined cycle, and rate of heat removed from the combined cycle. 

Determine the power required by the pump, power produced by the turbine, net power produced by the cycle, rate of heat added by the heat source, rate of heat removed to the heat sink, and cycle efficiency. Optimize the net power produced by the cycle with fixed pi. Draw the sensitivity diagram of net power versus pj. Find the maximum net power and p3 at the maximum net power condition. 

Determine the power required by the pump, power produced by the turbine, net power produced by the cycle, rate of heat added by the heat... 

A definition of the cycle rate is clear for steady states because stationary rates of all elementary reactions in cycle coincide. There is no common definition of the cycle rate for nonstationary regimes. In practice, one of steps is the step of product release (the "final" step of the catalytic transformation), and we can... 

The steady-state approximation on the base of the rule (13) is a linear function of the restored-and-cut cycles rate-limiting constants. It is the first-order approximation. 

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