A 4-m high, 15.24-cm diameter semi-batch bubble column connected to one of three perforated plate gas distributors with open area ratios A = 0.57%, 0.99%, and 2.14% is employed to study gas holdup and flow regime in Rayon and Nylon fiber suspensions. This study determines the effect of superficial gas velocity, fiber type, fiber mass fraction, fiber length, and aeration plate open area ratio on...

Gas holdup is one of the most important hydrodynamic parameters needed for reliable design, performance estimation, and scale-up of stirred tank reactors (STRs). In the present work, local gas holdup is measured in an acrylic stirred tank reactor equipped with a Rushton impeller using X-ray computed tomography (CT) for many different operating conditions. Power consumption for different operati...

This article develops the point that incentive and risk-bearing problems associated with contractual holdup may justify legal intervention. Contractual holdup is considered both for fresh contracts and for modifications of contracts. One type of legal intervention is flat voiding of contracts. Such intervention tends to be advantageous when holdup situations are engineered. Another type of inte...

An X-ray visualization technique has been used for the quantitative determination of local liquid holdups distribution and liquid holdup hysteresis in a nonwetting twodimensional (2-D) packed bed. A medical diagnostic X-ray unit has been used to image the local holdups in a 2-D cold model having a random packing of expanded polystyrene beads. An aqueous barium chloride solution was used as a fl...

Steady-state and transient experiments of water–gas, oil–water and oil–water–gas multiphase flows were conducted on a transparent 11 m long, 15 cm diameter, inclinable pipe using kerosene, tap water and nitrogen. The pipe inclination was varied from 0 (vertical) to 92 and the flow rates of each phase were varied over wide ranges. Fast-acting valves enabled the trapping of the fluid flowing in t...

In the present study, the influence of superficial gas velocity and fluid properties on gas holdup and liquid circulation velocity in a three-phase external loop airlift column using polystyrene (0.0036 m diameter and 1025.55 kg/m density) and nylon-6 (0.0035 m diameter and 1084.24 kg/m density) particles with aqueous solutions of alcohols (isoamyl alcohol and propanol) as liquids were investig...

This paper analyzes the problem of …rms that need to make investment decisions in capital markets characterized by trading frictions and ex-post bargaining. Trading frictions make switching from one capital supplier to another costly, thus implying that the match between …rms and suppliers generates surplus. Ex-post bargaining implies that suppliers can appropriate part of this surplus. Firms r...

Why don’t VCs eliminate excess demand for follow-on funds by raising fees? We propose a model of learning that leads to informational holdup. Current investors learn about skill whereas outside investors observe only returns. This gives current investors holdup power when the VC raises his next fund: Without their backing, no-one will fund him, as outside investors interpret the lack of backing...

This paper scrutinizes the effects of investor-state dispute settlements (ISDS) and national treatment provisions in a two-period model where foreign investment is subject to domestic regulation and a holdup problem. It shows that ISDS can mitigate the holdup problem and increases aggregate welfare, but comes with additional regulatory distortions for the first period. A national treatment prov...

Focus — specialization and speciÞc technology — improves productivity but leads to more dependency and opens a door for power problems. We analyze how organizational design and the choice of technology interact with the allocation of ownership in minimizing the holdup problem in the property rights theory of Grossman-Hart-Moore. We Þnd a novel motive for job rotation: rotation reduces holdup pr...