Abstract: A multi-stage solar concentrator (10) for use in a magnetohydrodynamic (MHD) electrical power generation system or process heating applications, said concentrator including a static planar solar collector (11), a paraboloidal mirror (12) receiving photons from the planar solar collector, and a compound parabolic solar concentrator (13) receiving photons from both said planar solar collector and said paraboloidal mirror. Suitably a solar oven (15) adapted for use in a fluid circuit of the MHD system or in process heating receives concentrated solar energy from the solar concentrator (10) via a transparent window (14).

Abstract: A method of effecting commerce in a networked computer environment in a computerized system is disclosed. A database of vendor product data and an associated database interface is established on a first computer. The interface allows remote access by one or more user(s). A local user interacts with the database by querying the database to specify a local users product/service specification. The database provides the local user with a selection of remote vendor network sites, where the selection is determined on the basis of the user querying the database. After the local user interactively connects with one or more of the remote vendor network sites, the user selects products/services from the information provided on the remote vendor network site. The selection of a particular product/service triggers a transaction notification which records the users selection and associated financial transaction data which is transmitted to the database and associated database interface.