Non-equilibrium phases in Al-rich Al-Pt alloys

The solid solubility of Pt in Al was extended from 0 to 2 at. % by “two-piston” quenching technique. The stability of the Al-Pt solid solution during annealing is discussed. During the decomposition an intermediate metastable phase was detected, the unit cell constants of which were determined.     

Beitrag zur Bestimmung der Schwingungsrichtung bei ruhenden Dampfturbinenschaufeln mit Deckband

Zusammenfassung Für ruhende Dampfturbinenschaufeln mit einem Deckband wird ein Verfahren zum Berechnen der Richtung der Schaufeleigenschwingungen unter der Annahme entwickelt, da? bei den Schwingungen die gesamte Form?nderungsarbeit einen Kleinstwert annimmt. Ein Vergleich mit Versuchsergebnissen zeigt, da? diese Theorie bessere Werte liefert als bisher verwendete Verfahren.     

Euclid’s Elements in the Czech Lands

[Terentianus 1st – 2nd century A.D.]

This article is dedicated to Euclid’s Elements, to translations of this work into Czech, and to the translators who have taken on the task of translation. It contains a short overview of the results achieved during a three-year project supported by the Czech Grant Agency.We explored how Euclid’s Elements were spread around the Czech lands.We will try to describe the circumstances that lay behind attempts to translate the Elements into the Czech language.     

First results on patient dose measurements from conventional diagnostic radiology procedures in Serbia and Montenegro

The objective of this work is to assess patient doses for the most frequent X-ray examinations for the first time in Serbia and Montenegro. A total of 510 procedures for 11 different examination categories in 3 general hospitals were analysed. Mean and median entrance surface air kerma (ESAK) and kerma area product (KAP) values followed by mean effective doses were reported. Using X-ray tube output data, ESAK for each radiographic examination was calculated, as well as the effective dose for each patient. Except for chest PA examination, all estimated doses are less than stated European and International Atomic Energy Agency (IAEA) reference levels for simple radiographic examinations. For complex examinations involving fluoroscopy and radiography total KAP was measured and contributions from fluoroscopy and radiography were assessed. The study of KAP confirms that the dose level for complex fluoroscopy investigations is closely related to the technique and individual patient variation in terms of fluoroscopy time and number of radiography exposures. The obtained values are comparable to those reported in the UK. Survey data are aimed aid development of a national quality control and radiation protection programme for medical exposures.     

Phase retrieval errors in standard Fourier fringe analysis of digitally sampled model interferograms

We investigate the reliability of phase retrieval by use of the fringe Fourier analysis method for measuring the displacements of facets during the growth of equilibriumlike-shaped crystals. The mean phase change between two successive interferometric images contains an inherent error that emerges from the noninteger number of fringes in the image field. The magnitude of the retrieved phase error of the ideal fringe pattern is investigated as a function of spatial carrier frequency, of the initial phase setting, and of the deviation of the number of fringes from the nearest integer value. The suggested modified algorithm suppresses the error more than threefold.     

Determination of As(III) and As(V) in oilseeds by chronopotentiometric stripping analysis: development of a method

Chronopotentiometric stripping analysis (CSA) was used for selective determination of As(III) and As(V) in different oilseeds. After the optimization of experimental parameters an appropriate procedure for sample pretreatment was developed. A detection limit of 2 microg/dm3 for As(III) was obtained with an electrolysis time of 600 s. This method was used for arsenic determination in sunflower, pumpkin, and flax seed, as well as for soy flakes and almond.     

Conformal anodic oxidation of aluminum thin films

Membrane-based synthesis, also called template synthesis, is a very general approach used to prepare arrays of nanomaterials with monodispersed geometrical features. The most commonly used porous templates are track-etched polycarbonate and porous anodic alumina membranes. Common to all these templates is the fact that the pores are perpendicular to the surface of the membrane. Here, a novel approach is presented, where the pores are synthesized parallel to the surface of the membrane. For the first time, the anodic oxidation of an aluminum thin film is performed laterally, i.e., parallel to the surface of the substrate, instead of perpendicular as usually done. For low anodic oxidation voltages (between 3 and 5 V) we obtain highly regular and ordered pore arrays, at least over a few hundred nanometers length, with a minimum pore size of approximately 3 to 4 nm. With such porous alumina structures, the controlled in-plane organization of arrays of template-grown nanowires and carbon nanotubes for reproducible device fabrication should be much easier.