University of Saskatchewan

About: University of Saskatchewan is a education organization based out in Saskatoon, Saskatchewan, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 25021 authors who have published 52579 publications receiving 1483049 citations. The organization is also known as: USask.

Fischer–Tropsch synthesis: A review of water effects on the performances of unsupported and supported Co catalysts

Abstract: Fischer–Tropsch synthesis (FTS) process aims at converting synthesis gas to liquid fuels. Due to high activity and long catalyst life, cobalt-based catalyst is currently the catalyst of choice for gas to liquid (GTL) technology. Water is most undesirable byproduct of FTS process. Due to low water–gas-shift (WGS) activity of cobalt-based catalyst, the water concentration rises with time-on-stream (TOS) in FTS. This paper reviews the effects of water on the performances of various cobalt catalysts for FTS. The effects of water on FTS is quite complex and depends on the support and its nature, Co metal loading, its promotion with noble metals, and preparation procedure. Added water up to certain concentrations has positive effects (in terms of higher CO conversion, C 5+ selectivity, olefin selectivity and lower methane and CO 2 selectivity) on unsupported cobalt oxide catalysts. If the effects of support are taken into account, water has positive effect for silica-supported catalysts. The effects are negative for alumina where as for titania support, water has little positive effect. However in general, oxidation of cobalt active site depending on the cluster size and water partial pressure, the removal of transport restrictions via the formation of water-rich intra-pellet liquids, and kinetic effects have been considered as the main responsible factors. The effects are strongly influenced by the cobalt cluster size as well as on pore size of the support. Addition of noble metals at low cobalt loading increases the dispersion of cobalt on the support and hence improves its activity. Higher cobalt dispersion enhances the negative impact of water especially at higher water partial pressures under FTS conditions.

Medical tourism today: What is the state of existing knowledge?

Abstract: One manifestation of globalization is medical tourism. As its implications remain largely unknown, we reviewed claimed benefits and risks. Driven by high health-care costs, long waiting periods, or lack of access to new therapies in developed countries, most medical tourists (largely from the United States, Canada, and Western Europe) seek care in Asia and Latin America. Although individual patient risks may be offset by credentialing and sophistication in (some) destination country facilities, lack of benefits to poorer citizens in developing countries offering medical tourism remains a generic equity issue. Data collection, measures, and studies of medical tourism all need to be greatly improved if countries are to assess better both the magnitude and potential health implications of this trade.