Progres on Pulping

PROGRES for Beginners

Graph Grammar Engineering with PROGRES

Graph-like data structures and rule-based systems play an important role within many branches of computer science. Nevertheless, their symbiosis in the form of graph rewriting systems or graph grammars are not yet popular among software engineers. This is a consequence of the fact that graph grammar tools were not available until recently and of the lack of knowledge about how to use graph gram...

Graph Pattern Matching in PROGRES

The work reported here is part of the PROGRES (PROgrammed Graph Rewriting Systems) project. PROGRES is a very high level multi paradigm language for the specification of complex structured data types and their operations. The data structures are modelled as directed, attributed, node and edge labeled graphs (diane graphs). The basic programming constructs of PROGRES are graph rewriting rules (p...

Pulping Catalysts in Trees

Several hardwood and softwood trees were analyzed for anthraquinone-type components. Wood samples were reduced to a small size and extracted with an organic solvent; the extracts were then concentrated and analyzed by gas chromatography-mass spectroscopy. Low levels of AQ and anthrone components were detected using a sensitive selected-ion monitoring technique. Ten out of seventeen hardwood sam...

Deresination Options in Sulphite Pulping

Three methods for improved deresination of sulphite pulps were evaluated, namely, alkaline washing, enzyme treatment, and pulp fractionation. Alkaline washing appears to come at a high cost, because caustic is expensive and affects cellulose chain length, as indicated by lower viscosity of the pulps. Thus this is not a viable option for pulps that are sensitive to changes in viscosity. Enzyme t...