The gas holdup behavior in a nylon fiber suspension with various fiber lengths (L = 2, 3, and 6 mm) is investigated. Experiments are performed over a range of superficial gas velocities (Ug≤ 18 cm/s) and a range of fiber mass fractions (0 ≤ C ≤ 1.8%) in a 15.24-cm-diameter semibatch bubble column. Day-to-day variations in the gas holdup create difficulties in interpreting the effect of the fibe...

ISSN 2277 5056 | © 2012 Bonfring Abstract--Fluidization is an operation in which solid particles are kept under suspension supported by the upward flow of liquid/gas phase. In classic fluidization the solids density are higher than the liquid, where as in Inverse fluidization the solids density are lower than that of continuous liquid phase. The phase holdup measurements in three phase classic/...

Gas holdup and bubble size are important parameters for simulation and designing in bubble column reactors. Because based on these parameters, the available gas-liquid interfacial area is defined for mass transfer. In this paper, the results of applying magnetic fields on the velocity field and volume fraction of gas holdup are reported. Hydrodynamics of the bubble column in the reactors is inv...

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...

In this study, the effect of operating parameters on dispersed phase holdup in liquid-liquid extraction process has been investigated. Three chemical systems (Toluene/Water, Butyl acetate/Water, and n-Butanol/Water) were utilized and holdup was considered in a wide range of interfacial tensions through a Scheibel extraction column. Various rotor speeds were examined on the certain velocities of...

In this paper, we present an experimental study on mass transfer of oxygen into water in an oscillatory baffled column (OBC). The objective of this work is to establish the contribution of individual parameters, such as the size of bubbles and the gas holdup, to the overall volumetric mass transfer coefficient (kLa). Our results show that the gas holdup is the most important factor. The liquid-...

Experiments have been carried out in a 0.1 m internal diameter, 1.88 m height vertical Plexiglas column with an antenna type modified air sparger in the gas-liquid distributor section. This arrangement provides uniform mixing of the fluids, ensures the gas entering the fluidizing section as fine bubbles and reduces the pressure drop encountered through a conventional distributor used for the pu...

The gas holdup and flow dynamics in a laboratory scale Rushton-turbine flotation tank were simulated using the dispersed k- turbulence model and Eulerian-Eulerian multiphase modelling approach. The inherent uncertainties in the CFD predictions were quantified by examining the model and numerical (i.e., discretization) uncertainties. The contribution of model uncertainty was explored by conside...

A seller can make investments that affect a tradable asset’s future returns. The potential buyer of the asset cannot observe the seller’s investment prior to trade, nor does he receive any signal of it, nor can he verify it in anyway after trade. Despite this severe moral hazard problem, this paper shows the seller will invest with positive probability in equilibrium and that trade will occur w...

T complexity and scope of outsourced information technology (IT) demands relationship-specific investments from vendors, which, when combined with contract incompleteness, may result in underinvestment and inefficient bargaining, referred to as the holdup problem. Using a unique data set of over 100 IT outsourcing contracts, we examine whether contract extensiveness, i.e., the extent to which f...