Industrialized nations face a critical problem in replacing the sources of liquid fuels that traditionally have been supplied by petroleum. One solution that has gained increasing support in this country is the use of ethanol produced by fermentation of renewable biomass as an extender in, or supplement to, gasoline for transportation fuel. Distillation, the present method of separating ethanol from the fermentation broth, is an energy-intensive one and frequently uses more energy than is available from the ethanol recovered. There are many investigations under way to find alternative, less energy-intensive techniques for the ethanol-water separation. The separations method described in this article involves the use of solid materials to preferentially remove ethanol from fermentation broths. Subsequent stripping of the ethanol from the sorbent with a dry gas reduces dramatically the energy required for the separation. Three solid sorbents have been investigated experimentally. Their sorption/desorption characteristics are described, and their incorporation in an ethanol recovery process is evaluated. Three sorbents were investigated: two commercially available divinylbenzene crosslinked polystyrene resins in bead form (one with a nominal surface area of 300 m(2)/g, the other with 750 m(2)/g) and an experimental proprietary molecular sieve with hydrophobic properties. Equilibrium adsorption isotherms for two of the sorbents were obtained at ambient temperature (21 degrees C) for ethanol-water solutions containing up to 12 wt. % ethanol. In addition, 40 degrees C isotherms were obtained for the polystyrene sorbents. Although different, the equilibrium isotherms for the sorbents indicated that ethanol could be preferentially sorbed from a dilute solution. Column breakthrough curves indicated very favorable kinetics. Desorption of the ethanol was readily effected with warm (60-80 degrees C), dry nitrogen.

We describe the development and examine the performance of a slurry containing an organic acid salt, a silica abrasive obtained from the hydrolysis of ethyl silicate ͑TEOS͒, and a passivating agent for the chemical mechanical planarization ͑CMP͒ of Cu damascene structures. The study is performed on full ͑200 mm͒ wafers coated with blanket Cu films to examine removal rates and uniformity and on partial wafers to investigate the CMP of Cu damascene structures. The silica slurry shows moderately high removal rates, good uniformity values, low defectivity, and excellent ability to remove the Ta liner. It is demonstrated that despite the fairly low Cu to SiO 2 selectivity values, a severe erosion of the SiO 2 does not occur. Because of the effective removal of the liner material, long overpolishing times become unnecessary, thus, spacer erosion is avoided. Corrosion induced defects are prevented by the addition of a passivating agent.

Research on the behaviour of polycrystalline graphite exposed to neutrons from nuclear fission reactions began around the year 1942. Up to today, many serious questions concerning properties and structural changes have been answered and in many countries graphite became a standard material for the core of gas-cooled reactors. However, the basis for that is a broad knowledge about manufacturing and a huge amount of numerical data from irradiation testing. After many years of successful use of graphite, new problems concerning the lifetime of graphite parts have arisen. In order to deal with these challenges a critical review is necessary of what we know, and of what is only subject to speculation. Difficulties with the interpretation of experimental data using classical models are discussed, and some new speculative ideas are presented.

Jul-1575 GA-A15270 UC-77 PROPERTY CHANGES IN GRAPHITE IRRADIATED AT CHANGING IRRADIATION TEMPERATURE by R. J. PRICE (General Atomic Company) G. HAAG (Kernforschungsanlage, Jiilich GmbH) Prepared under the Umbrella Agreement for Cooperation in Gas-Cooled Reactor Development between the United States and the Federal Republic of Germany. Work supported in part by l^^r^^^rr-Contract DE-AT03-76ET35300 fef&5S?^ the San Francisco Operations Office to^fnSv5| Department of Energy l^feStSS uumraci UC-H I UJ-/DC I J: for the San Francisco Operatior Department of Energy GENERAL ATOMIC PROJECT 6400

The fixation of CO™, may fee required at some faito-re time because of 14 the significant fractional contribution of €, via the fagestcicm pathway* to the total popuLLatiani ciase fromi tite nuclear fuel cycle, even tiroagli t&e actoal qiTftn-tity of tficis dose is; very small when comparedi ta> natinraJL badeground. The: work described! here was done in support of fuel reprocessming development, $£ bot& grafrhdlte fuel ([MIGEs;)i and! metal-cladi fuel QjLWXs, and EMFBRs}, and was direetedi to the comtroil of ' CQu releasedi dluaring, repirocessimg; operaitions., However, portions; of this work are also-applicable 14 ta the control of COk released! during reactor operatioa^ Ihe wo>rk described; falls; in three major" areas: • Tlie application' of liquid-slurry fixation witit ŵ hich concerts the COH to> G' aOTw,, carried! oat after treatment of the CQw-conitaimimg, stream to remove otfeear gaseums 85 radioactive componenits, tnainily Er» TTliis; approach is; primarily fo>r applieatioo to> KEGR fuel repracess;inig. The above process foir CO™ fisatiaim,, but used ahead of Kr removal, and! fallome have app)lica.tionj to, metal-dadl fmei irep:racessimg; and. toi reactor The use of solid BaCOffi))-hydrate,, reacting directly with the gaseoxis pfese. UMLs pitacess is. generally applicable to botb; repcocessinig and tto> reactor operationi. Eesearchi spomsar-edl by the Office <»ff Etodsaar ?fes;te Management, IDi.S. Itepart oif Energy tander conitract W-MQS-emg-ZS with the liuioni Caorfeide Co-rpocatiam