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1. An act that requires use of resources or time. In Program Evaluation and Review Technique (PERT), an activity is represented by an arrow on a PERT chart.

2. In investing, the amount of a security's relative trading volume; that is, the amount of money flowing into and out of a security in trading. A high amount of activity means that many shares of the security are being bought and sold at a high rate, while a low level of activity indicates the opposite.


The amount of relative trading volume in a security.
References in periodicals archive ?
As such, apparent activity coefficients for lower alcohols diluted into hydrocarbon solutions are often very much greater than one.
The specific retention volume, Vg0, glass transition temperature, Tg; adsorption enthalpy, IHa; the sorption enthalpy, IH1S; sorption free energy, IG1S; sorption entropy, IS1S; the weight fraction activity coefficients of solute probes at infinite dilution, a|1a, partial molar enthalpy of solute probes at infinite dilution, IH1a; and Flory-Huggins interaction parameters, I12a; between polymer and solvents were determined in the temperature range of 493-343 K for poly(ABM) and 473-343 K for poly(ABM%41-coAN)-poly(ABM%71-coAN).
Activity coefficient of a species in a solution represents the relation between the real fugacity and the fugacity corresponding to an ideal solution (calculated via Lewis-Randall rule).
These solvent heats of vaporization values, derived from the experimentally determined activity coefficients, can be compared with the ones estimated employing the Watson model [18] as a kind of consistency test, in order to check the goodness of the experimental data.
Accurate measurement of activity coefficients at infinite dilution by inert gas stripping and gas chromatography.
Hence, the VLE model itself is valid at low acid gas partial pressures even though the parameters of the activity coefficient model were not fitted in this range (Kundu, 2004).
The mean activity coefficients calculated by eq (1) from these smoothed values of E and the values of E[degrees] given in table 1 are summarized in table 3.
Depending on specific retention volumes, V 0, of probes the w ht activity coefficients of solute probes at infinite dilution, 1[?
Thus, activity coefficient for single component in membrane (State I) is
By obtaining the weight fraction activity coefficient, O1 , the partial molar free energy, DG1, and the average partial molar enthalpy, DH1 values can be calculated from following relations, respectively at infinite dilution [31-33].
i], T) is the activity coefficient of species i as function of liquid composition [x.