Abstract abstract reduction

We propose novel algebraic proof techniques for rewrite systems. Church–Rosser theorems and further fundamental statements that do not mention termination are proved in Kleene algebra. Certain reduction and transformation theorems for termination that depend on abstract commutation, cooperation or simulation properties are proved in an extension with infinite iteration. Benefits of the algebraic approach are simple concise calculational proofs by equational reasoning, connection with automata-based decision procedures and a natural formal semantics for rewriting diagrams. It is therefore especially suited for mechanization and automation.     

Reductive silylation and alkylation of phthalimides

Preparative electrochemical reduction of N-methylphthalimide in dry acetonitrile and in the presence of dimethylsulfate or trimethylchlorosilane lead to bis-lactams by dimerization at the carbonyl group. 1, 3-Bis-trimethylsilyloxy-2-methylisoindole is formed instead using a large excess of silylating agent. An analogous isoindole derivative is obtained from reduction of N-phenylphthalimide. A mechanism accounting for the formation of one or two electron products under different alkylating conditions is discussed.     

Optimierung spektrometrischer Verfahren durch ein Datenverarbeitungssystem

Einsatz von Prozeßrechnern in Laboratorien. Aufbau eines Systems zur Produktionsüberwachung eines Sauerstoffaufblasstahlwerkes. Beschreibung des Rechners und der Programmgestaltung. Ablauf der emissionsspektrometrischen und röntgenfluoreszenzspektrometrischen Roheisen-, Stahl- und Schlackenanalysen. Erste Ergebnisse und Erfahrungen.     

Bekämpfung der Computerkriminalität

Die Autoren setzen sich mit dem Gesetzentwurf zur Bek?mpfung der Computerkriminalit?t auseinander, insbesondere mit der Strafbarkeit des Einsatzes von Analysetools.     

Beyond low-level activity: on a "non-radioactive" gas mantle

Gas mantles for camping gas lanterns sometimes contain thorium compounds. During the last years, the use of thorium-free gas mantles has become more and more popular due to the avoidance of a radioactive heavy metal. We investigated a gas mantle type that is declared to be "non-radioactive" and that can be bought in Austria at the moment. Methods used were Instrumental Neutron Activation Analysis (INAA), gamma-spectroscopy, and Liquid Scintillation Counting (LSC). We found massive thorium contents of up to 259 mg per gas mantle. Leaching experiments showed that only 0.4% of the Th but approximately 90% of the decay products of (232)Th can be leached under conditions simulating sucking and chewing with human saliva. In this paper, the investigation of these gas mantles including the consideration of the environmental hazard caused by disposed mantles and the health hazard for unsuspecting consumers is presented and legal consequences are discussed for this fraud.