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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 ?
2) In the ideal behavior modeling, the activity coefficients for the components are kept constant value of 1 and obey Raoult's law.
Because the effect of the polymer properties such as (i) chain length, (ii) molecular size, and (iii) molecule structure are not accounted on the activity coefficients in the ideal behavior modeling.
Similar expressions for logarithm of activity coefficient can be derived for other molecular and ionic solutes.
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 extrapolation method of Harned and Ehlers, which expressed the activity coefficient in eq (1) by the Debye-Huckel limiting law, was used to obtain all of the potentials except those given in the last column.
Activity coefficient of hydrochloric acid from 0[degrees] to 90[degrees] C m 0[degrees] 10[degrees] 20[degrees] 25 [degrees] 30[degrees] 0.
Apparent activity coefficients of the monomer species in solution as a function of concentration are computed from van Laar coefficients of [A.