A model is developed for prediction and interpretation of the observed steady-state axial dissolved oxygen concentration profiles in tall bubble columns. The observed concentration profiles are non-linear, unlike what would be expected if the hydrostatic pressure alone influenced the profiles. The non-linear profiles result from the axial mixing of liquid in the column. Several other factors in...

Firms in many situations must make investment decisions long before they meet with new capital suppliers. In addition, most physical capital is specific to a task or location, thus implying potentially important switching costs in case negotiations between a firm and a supplier break down. The present paper analyzes the implications of these frictions. The sequentiality of investment makes it i...

Flotation is a complex process that exhibits high dimensionality which makes modeling and optimization very challenging. One technique to alleviate the problem combine variables together into more informative ones. Bubble surface area flux air recovery are examples of reduction. Gas holdup also captures effect plurality including gas rate, bubble size, surfactant type, concentration. This work ...

A robust nonlinear control law is designed to reject unknown feed composition disturbances with overall stability. Implementation to real columns as well as comparisons with classical control strategies, show the robustness and flexibility improvements of the method. Almtracq-Using singular perturbation techniques on a physical model of distillation column, an aggregated model is proposed for c...