Die Umströmung einer sich frei bewegenden Kugel in einem rotierenden Fluid

Zusammenfassung Es wird die Umstr?mung einer Kugel behandelt, die sich frei durch starr rotierendes Wasser bewegt. Auf experimentellem Weg wird gezeigt, da? das Gebiet in dem sich die Kugelbewegung bemerkbar macht, offensichtlich eine kegelartige Form mit ellipsen?hnlichem Querschnitt hat. Der Winkel des Kegels scheint linear von der Rossbyzahl abzuh?ngen. W?hrend die l?ngere Ellipsenachse linear w?chst, erreicht die kurze Achse rasch einen Wert von etwa fünf Kugeldurchmessern, der dann nicht weiter anw?chst. Vergleiche mit Kugelbewegungen in nicht rotierenden Fluiden zeigen, da? die beobachtete Umstr?mung wesentlich von der Rotation des Wassers beeinflu?t wird. Diese Arbeit entstand mit finanzieller F?rderung durch die Deutsche Forschungsgemeinschaft am Hermann-F?ttinger-Institut der Technischen Universit?t Berlin.     

Polyacrylamide bei der steinkohlenaufbereitung

By means of lab scale studies and electrochemical potential measurements it was shown that by selective flocculation using combinations of low molecular anionic polyelektrolytes and high molecular flocculants a coal slurry can be separated into a high ash content slurry and a thickened coal sludge. The dispersed matter contains almost only ultrafine mineral particles of high ash content. The flocculated coal particles which are virtually free of ultrafine mineral can now be treated in a highly efficient flotation step and dewatered to rather low water contents on vacuum filters.     

DInSAR investigation in the Pärvie end-glacial fault region,Lapland, Sweden

Northern Fennoscandia bears witness to the Pleistocene glaciation in the form of a series of large faults that have been shown to have ruptured immediately after the retreat of the ice sheet, about 9500 years ago. The largest one, known as the Pärvie fault, consists of a 155 km long linear series of fault scarps forming north–northeast-trending, that stretch west of Kiruna, Lapland. End-glacial intra-plate faults of this extent are very rare in the continental crust and the Pärvie system represents one of the major fault zone structures of this type in the world. Seismological evidence shows that there is still noticeable seismic activity, roughly one event of magnitude 2 per year that can be attributed to the fault. Nevertheless assessing its state of activity is a difficult task due to the extent and remoteness of the area. This study is aimed at the determination of crustal motion around the Pärvie fault zone using the differential inter-ferometric synthetic aperture radar (DInSAR) technique, based on images acquired with the European Space Agency (ESA) satellites European Remote Sensing (ERS) 1, ERS-2, and the Environmental Satellite (ENVISAT). We present results achieved in terms of deformation of the crystalline bedrock along different sectors of the fault where high levels of coherence were obtained, even from image pairs several years apart. This finding does not exclude deformation in other segments, as observing conditions are not always as favourable in terms of data availability.     

Wasserstoffbrückenbindungen in Lösungen ortho-phosphorylsubstituierter Phenole

Hydrogen Bonds in Solutions of Ortho Phosphoryl Substituted Phenols In contrast to open-chained phosphoryl-enols 1 the ortho-P(O)-substituted phenols 4 may be conveniently obtained by cleavage of phenol alkylethers. R_f-values (TLC) demonstrate that the phenols 4 exhibit PO ⃛ HO hydrogen bonds in solution if the basizity of the phosphoryl O-atom is sufficient. Electronwithdrawing P-substituents lower the probability of this interaction. δ_OH and P_ka data demonstrate that in dimethylsulfoxide only phosphinoxides 4a–g give PO ⃛ HO bridges. Arylesters of phosphonic acids 4i–k add DMSO-molecules via SO … HO hydrogen bonds. This difference is mainly a result of inductive effects. UV-spectra refer to a probably small contribution of P-phenyl substituents to conjugation.     

Darstellung und 1H-NMR-spektroskopische Untersuchung von β-substituierten Äthylen-phenylphosphinsäure-äthylestern

Preparation and ¹H N.M.R. Spectroscopic Investigation of β-Substituted Ethyl Esters of Ethylene-phenylphosphinic Acid The ethyl ester 3 of diphenylphosphorylmethyl-phenyl-phosphinic acid in benzene reacts regiospecifically and stereoselectively with aldehydes, in presence of sodium hydride, to 2-substituted ethyl esters of trans-ethylene-1-phenylphosphinic acid 8 (E-isomers) in satisfactory yields. The ABX type H-n.m.r. spectra of isolated pure products 8 were analysed. The trans configuration of these compounds is characterized by the specific signal sequence of ethylene proton H_B.     

Zur Konzentrationsabhängigkeit der Fällungspunkte von Polymerlösungen

The concentration dependence of the cloud points of dilute benzene solutions of polystyrenes with broad and narrow molecular distributions was determined via titration with methanol or isopropanol using visuell determination, colorimetry and light scattering. All methods gave a linear dependence of the volume fraction φFM of the non-solvent from the logarithm of the polymer concentration c_p at the cloud point for three decades of c_p if certain evaluation techniques are used. Light scattering was the most accurate, visuell observation the least accurate method. The slope coefficients k of the function φFM = f(log c_p) depend linearly on 1/M^0,6 for polystyrenes of narrow molecular weight distribution.     

Application of Prediction Error Filters for the Detection of Weak Teleseismic Events

This paper analyzes how the signal-to-noise ratio (SNR) for digital registrations of weak earthquakes can be enhanced by application of prediction error filters. Two prediction algorithms are considered: A linear prediction filter and an adaptive autoregressive moving average (ARMA) filter. The effects of the filter parameters on the noise suppression rate and on the quality of spectral approximation are discussed. Results are given for broad-band and short period data of the Graefenberg array. The signal-to-noise gains achieved by prediction error filtering are examined for a series of weak events.