The occurrence of mistral winds in the Mediterranean shows a correlation with blocking activity over the eastern Atlantic. Apparently for this reason periods with a ''midwinter dip'' in the zonal available potential energy of the northern hemisphere are favored by mistral occurrence. There also is a tendency for a 22- to 26-day cycle to appear in pressure gradients at the 500- and 100-mb surfaces along the southern coast of France. Such pressure gradients, if they exceed a certain magnitude, are indicative of mistral episodes.

Fly ash derived from coal combustion contains predominantly spherical particles which consist of an insoluble aluminosilicate glass containing several mineral impurities. An outer layer, 50 to 300 A thick, is rich in many potentially toxic trace elements in the form of simple and complex sulfates. This layer, which is soluble in water, contains essentially all of the particulate sulfur present in fly ash in the form of sulfate. The actual mechanism(s) of formation of particulate sulfate salts are ill-defined but probably involve adsorption of condensation of gaseous sulfur species onto fly ash surfaces within the power plant stack system.

Two types of evacuated tube solar collectors have been operated in space heating, cooling and domestic hot water heating systems in Colorado State University Solar House I. An experimental collector from Corning Glass Works supplied heat to the system from January 1977 through February 1978, and an experimental collector from Philips Research Laboratory, Aachen, which is currently in use, has been operating since August 1978. A flat absorber plate inside a single-walled glass tube is used in the Corning design, whereas heat is conducted through a single glass wall to an external heat exchanger plate in the Philips collector. In comparison with conventional flat-plate collectors, both types show reduced heat losses and improved efficiency. For space heating and hot water supply in winter, the solar delivery efficiency of the Corning collector ranged from 49% to 60% of the incident solar energy. The portion of the space heating and domestic hot water load carried by solar energy through fall and winter ranged from 50% to 74%, with a four-month contribution of 61% of the total requirements. Data on the Philips collector are currently being analyzed.

Extrusion and rolling processes exhibiting large amounts of plastic flow are analyzed using a finite element technique that is based on a modified creeping viscous flow approximation. The technique, called the initial stress-rate method, iteratively corrects creeping viscous flow solutions to generate results that include elastic response. The momentum equations have been coupled with the energy equation to provide the capability to predict thermomechanical response during forming operations.

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