Mathematical theory of reduction of physical parameters and similarity analysis

The method of similarity analysis in the study of differential equations is extended to study the variability of parameters in a physical system. The analysis provides an insight into the meaning of physical similarity, which usually means the possibility of a reduction in the number of physical parameters characterizing the system. Theorems relating similarities to groups of invariant transformations are proved and employed to show how the number of parameters can be reduced.     

Operating characteristics and modeling of the LLNL 100-kV electricgun

In the electric gun, the explosion of an electrically heated metal foil and the accompanying magnetic forces drive a thin flyer plate up a short barrel. Flyer velocities of up to 18 km/s make the gun useful for hypervelocity impact studies. The authors review the technological evolution of the exploding-metal circuit elements that power the gun, describe the 100-kV electric gun designed at Lawrence Livermore National Laboratory (LLNL) in some detail, and present the general principles of electric gun operation. They compare the experimental performance of the LLNL gun with a simple model and with predictions of a magnetohydrodynamics code     

The measurement of slope using shearography

This paper presents an optical method which is based on speckle-shearing interferometry for the measurement of the slope at any point of an object. The object under study is illuminated by an expanded laser beam and its image is recorded on a photographic plate placed at the image plane of an image-shearing camera. A second exposure on the photographic film is made after the light source is moved slightly. The resulting photograph yields a fringe pattern which represents lines of constant displacement gradients. Theory of the method as well as some experimental results are presented.     

Natural radioactivity in groundwater--a review

The issue of natural radioactivity in groundwater is reviewed, with emphasis on those radioisotopes which contribute in a significant way to the overall effective dose received by members of the public due to the intake of drinking water originating from groundwater systems. The term 'natural radioactivity' is used in this context to cover all radioactivity present in the environment, including man-made (anthropogenic) radioactivity. Comprehensive discussion of radiological aspects of the presence of natural radionuclides in groundwater, including an overview of current regulations dealing with radioactivity in drinking water, is provided. The presented data indicate that thorough assessments of the committed doses resulting from the presence of natural radioactivity in groundwater are needed, particularly when such water is envisaged for regular intake by infants. They should be based on a precise determination of radioactivity concentration levels of the whole suite of radionuclides, including characterisation of their temporal variability. Equally important is a realistic assessment of water intake values for specific age groups. Only such an evaluation may provide the basis for possible remedial actions.     

Fluororganische Synthesen IV, 1-Fluor-1-organyl-cyclopropane und andere Cyclopropan-Derivate durch Anlagerungsreaktion von «Nachfolge-Carbenen»

Fluoroorganic Syntheses IV: 1-Fluoro-1-organyl-cyclopropanes and other Cyclopropane Derivatives by Addition of ?Successor-Carbenes”? Treatment of chlorodifluormethane or dichlorodifluoromethane with methyllithium in the presence of an olefin affords 1-fluoro-1-methylcyclopropanes in fair yields. Depending on the particular reaction conditions, 1,1-difluorocyclopropanes, 1,1-dimethylcyclopropanes and 1-chloro-1-methylcyclopropanes may be obtained as well. Butyllithium and phenyllithium give rise to analogous products.     

Fluororganische Synthesen V Darstellung und Abwandlung von Chlorfluorcyclopropanen - Ein gezielter Zugang zu Fluorallylalkoholen

Fluoroorganic Syntheses V. Preparation and Transformation of Chlorofluorocyclopropanes. – A Selective Approach to Fluoroallylic Alcohols Chlorofluorocarbene addition to unsaturated compounds is particularly convenient and efficient in a two-phase system. This method works satisfactorily even if the olefin carries base-sensitive substituents. The resultant chlorofluorocyclopropanes can be ring-opened by silver-salt assisted acetolysis affording 2-fluorallylacetates, which yield 2-fluorallylic alcohols upon saponification.