Particle collection in small laboratory cyclones as a basis for the design of large-scale cyclones

Grade efficiencies must be measured in order to characterize particle collection in cyclones. For real, irregularly shaped partcles, the grade efficiencies depend on the shape and orientation of the particles and the flow around them. Therefore, the collection characteristics of cyclones should be defined in relation to spherical particles. Deviations occurring on the use of real, irregularly shaped dusts can then be attributed to a material influence. A fast and accurate measuring technique to determine the collection characteristic for spherical particles is described, followed by the presentation of results of extensive investigations on small model cyclones. A similarity relationship is presented. The validity of this relationship was confirmed by investigations with similar, larger cyclones.     

Bootstrap estimates of standard errors in validity generalization.

Bootstrapping is introduced as a method for approximating the standard errors of validity generalization (VG) estimates. A Monte Carlo study was conducted to evaluate the accuracy of bootstrap validity-distribution parameter estimates, bootstrap standard error estimates, and nonparametric bootstrap confidence intervals. In the simulation study the authors manipulated the sample sizes per correlation coefficient, the number of coefficients per VG analysis, and the variance of the distribution of true correlation coefficients. The results indicate that the standard error estimates produced by the bootstrapping procedure were very accurate. It is recommended that the bootstrap standard-error estimates and confidence intervals be used in the interpretation of the results of VG analyses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elektrochemische synthesen—XXI. Cyclovoltammetrische und epr-spektroskopische untersuchung des redoxverhaltens des [S4N5]−-ions

Whilst the anodic oxidation of (Bu₄N) [S₄N₅] in 0,15 M (Bu₄N) [BF₄]/CH₂Cl₂ yielded no detectable radical species, the cathodic reduction at ?40°C and at room temperature leads to epr spectra, which can be assigned to [S₄N₅]^2? and [SN₂]^? plus a species containing one N atom—possibly NS^.₂.     

Die reaktionsbeschleunigende Wirkung von Fluoriden beim Beizen verzunderter Eisenteile

The reaction-accelerating effect of fluorides during the pickling of scale-affected iron parts On the strength of the knowledge:

• 1 that the iron oxides Wüstite, Hematite and Magnetite are differently affected by normal pickling acids, and
• 1 that a very weak hydrofluoric acid dissolves bare iron exceptionally slowly, but magnetite exceptionally rapidly,

the solubility of the magnetites difficult to dissolve in acid was systematically tested in inorganic acids (HCl, H ₂ SO ₄ ) and in organic acids (formic acid, acetic acid, citric acid), with and without admixture of fluoric acid or bi-fluorides. The chemical reactions are represented in the form of reaction equations. Reference is made to the high inhibiting effect of commercial inhibitors and the useful technical application of highly diluted fluoric acid or fluor-activated acids in pickling technology.     

Die Sättigungslöslichkeit von Reineisen an Sauerstoff vom Schmelzpunkt bis 2046°C,ermittelt mit dem Schwebeschmelzverfahren

Kurze Beschreibung der verwendeten Schwebeschmelzanlage. Visuelle Ermittlung der Temperatur für die Sauerstoffsättigung. Auswirkungen der Verunreinigungen im verwendeten Reineisen auf das Beobachtungsergebnis. Vergleich der erhaltenen Ergebnisse mit Schrifttumsangaben aus Gleichgewichtsuntersuchungen in Tiegeln und aus einer Schwebeschmelzuntersuchung.