LEGALDISCLAIMER This reportwas preparedas an accountof worksponsored by • anagencyof the UmtedStatesGovernment.Neitherthe UnitedStatesGovernment nor anyagencythereof,nor anyof theiremployees, nor anyof theircontractors, subcontractors or theiremployees, makesanywarranty,expressor implied, d, or assumesanylegalliabilityor responsibility for the accuracy, completeness, or anythirdparty'suseor the results of suchuseofany information, apparatus, product, or process disclosed, or representsthat its

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... sewouldnotinfringe privatelyownedrights. Referencehereintoany specific commercial product, process, or serviceby tradename, trademark, manufacturer, or otherwise,doesnotnecessarily constituteor implyitsendorsement, recommendat=on, or favo'ing bythe UnitedStatesGovernment or anyagency thereofor itscontractors or subcontractors. Theviewsand opinionsof authorsexpressedhereindo notnecessarily state or reflectthoseof the UnitedStatesGovernment or any agencythereof. Thisreporthas beenreproduced fromthe bestavailablecopy. Availablein papercopyandmicrofiche. Avaalable tothe U.S. Departmentof Energy and=tscontractors from Oftice of ScientificandTechnical Information P.O. Box62 Oak Ridge,TN 37831 (615) 576-8401 Availableto the publicfrom the U.S. Department of Commerce NationalTechnical Information Service 5285 PortRoyaiRoad Springfield, VA 22161 (7O3)487-4650 Printed in the United States ol America DISCLM._ CHP (191) J