Deformation of liquid droplets during collisions with hot walls: Experimental and Numerical Results

Measurements of droplet deformation during wall impingement were performed for ethanol droplets and water droplets with diameters ranging from 100 to 200 μm. The wall temperature is well above the Leidenfrost temperature of the droplet liquid. With monodisperse droplet streams and a special illumination technique, slow motion images of the phenomena can be obtained. Measurements with high temporal resolution below 1 μs are possible using a standard video camera. The experimental results are compared with numerical results, which were obtained by solving the three-dimensional Navier-Stokes equations for incompressible fluids including surface tension effects. The fluids are treated with the volume-of-fluid method and the free surface is modeled according to the continuum-surface-force model. Numerical and experimental results show good agreement.     

Presentation of a new high speed paper tape reader

A high speed paper tape reader with a maximum speed of 1000 characters per second is described. Relevant principles of construction as well as operating characteristics are given in some detail.     

Chemistry of the neophyl radical. The reaction of neophylmagnesium chloride with carbon tetrachloride and 1,2-dibromoethane in the solution

Neophylmagnesium chloride reacts via an ionic pathway with CCl₄ which is a very reactive halide towards Grignard reagents. On the other hand with the less reactive dibromoethane, the lowest energy pathway seems to be electron transfer to yield neophyl radicals.     

Ratio matching: A statistical aid for discovering generic relationships among samples

A technique of matching the ratios of elemental concentrations of a sample with the equivalent ratios of other samples is described. The resulting correlations are indications of potential generic relationships among the samples. Experimental data based on 91 sediments analyzed for eight elements by neutron activation analysis is used to demonstrate the ability of the method. Three typical examples show the relatively high correlations achieved between samples for which close generic relationships could be explained, post facto, by geographical evidence.     

The Stereoselective Acylation of Racemic Secondary Alcohols with Phenyltrifluoromethylketene as an Experimental Test of the Stereochemical Analogy Model

Validity of the stereochemical analogy model^[1,2] for stereoselective reactions is tested on acylations of racemic chiral secondary alcohols with phenyltrifluoromethylketene. The product ratios for the diastereomeric esters formed can be calculated using a formula derived from the general model for the special case, the results agreeing with the experimental data within the accuracy of the measuring method (integration of the ¹⁹F-NMR signals).