Ex Parte WELSH et al - Page 4

          Appeal No. 1997-1791                                                        
          Application No. 08/485,304                                                  

               600C. and (2) direct exposure of the gel to burner                    
               flames as the particles pass along an iron channel or                  
               flight as in a direct fired rotary kiln.                               
          See column 2, lines 52-57.  In addition, Cohen discloses that               
          "[h]ot fluid energy milling of ASH to reduce the particle size              
          was found usually to cause smaller losses in PV compared to                 
          normal operation of the mill which showed a larger loss of PV"              
          (column 2, lines 58-61).  Furthermore, Cohen exemplifies high               
          temperature milling:  EXAMPLE I - 530C; EXAMPLE II - 500C+;               
          EXAMPLE III - 530C; EXAMPLE IV - approximately 510C;                      
          EXAMPLE VI - 240C-310C.  While EXAMPLE V does not specify the             
          temperature of the milling, the hydrogel is micronized in a                 
          heated fluid energy mill.  Hence, whether Cohen describes the               
          milled product as a hydrogel or an aerogel, it is clear that                
          Cohen does not employ the minimal temperature during milling                
          which appellants disclose as necessary for producing a hydrogel             
          having a volatiles content of at least 40 wt.%.  While the                  
          examiner points to claim 14 of Cohen which recites a lower limit            
          of 200C for drying the treated gel, which temperature the                  
          examiner characterizes as "clearly 'mild' enough to maintain the            
          hydrogel as such, as in De Wolf [sic, DeWolf]" (page 7 of                   
          Answer), there is no evidence that treating the Cohen gel at                
          200C would allow for the maintenance of the claimed volatiles              
          content.  Furthermore, there is no evidence that all hydrogels              
          have a volatiles content of at least 40 wt.%.                               


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