Unions:rent creators or extractors?

This paper proposes a model of workplace-specific unions that integrates two views of what unions do. One view holds that unions mainly engage in rent extraction. Another view holds that unions mainly engage in rent creation by providing agency services that increase workplace productivity. We demonstrate that the choice between the two activities is systematically related to the economic and regulatory environment in which the union operates. Product market competition encourages rent creation, while labor market deregulation encourages rent extraction. Moreover, we provide a rationale for why firms may want to subsidize unions. © The editors of the Scandinavian Journal of Economics 2005.

The design of a high pressure solvent extraction process using liquid ammonia as solvent

The literature on the potential use of liquid ammonia as a solvent for the extraction of aromatic hydrocarbons from mixtures with paraffins, and the application of reflux, has been reviewed. Reference is made to extractors suited to this application. A pilot scale extraction plant was designed comprising a Scm. diameter by 12Scm. high, 50 stage Rotating Disc Contactor with 2 external settlers. Provision was made for operation with, or without, reflux at a pressure of 10 bar and ambient temperature. The solvent recovery unit consisted of an evaporator, compressor and condenser in a refrigeration cycle. Two systems were selected for study, Cumene-n-Heptane-Ammonia and Toluene-Methylcyclohexane-Ammonia. Equlibrium data for the first system was determined experimentally in a specially-designed, equilibrium bomb. A technique was developed to withdraw samples under pressure for analysis by chromatography and titration. The extraction plant was commissioned with a kerosine-water system; detailed operating procedures were developed based on a Hazard and Operability Study. Experimental runs were carried out with both ternary ammonia systems. With the system Toluene-Methylcyclohexane-Ammonia the extraction plant and the solvent recovery facility, operated satisfactorily, and safely,in accordance with the operating procedures. Experimental data gave reasonable agreement with theory. Recommendations are made for further work with plant.

Using the Dempster-Shafer theory of evidence to resolve ABox inconsistencies

Automated ontology population using information extraction algorithms can produce inconsistent knowledge bases. Confidence values assigned by the extraction algorithms may serve as evidence in helping to repair inconsistencies. The Dempster-Shafer theory of evidence is a formalism, which allows appropriate interpretation of extractors’ confidence values. This chapter presents an algorithm for translating the subontologies containing conflicts into belief propagation networks and repairing conflicts based on the Dempster-Shafer plausibility.