Determination of trace amounts of some elements in armco steel by the neutron activation method

The previously elaborated methods of the determination of As, Sc, La, Au, W, Mo, Ga and In have been adapted to the analysis of steel. Samples of Armco steel taken from three various points of a steel bar section were analysed. On the basis of the results obtained the distribution of the elements determined along the steel bar section is discussed.     

Energy bands of the BCC metals rubidium and cesium

Energy bands of BCC rubidium and cesium are calculated for the first time using the full non-local but energy-independent Shaw's optimized model potential. The energy dependence of the potential is then included as first order perturbation. The effects of changing the model potential and of reversing the sign of the depletion charge d are reported. The Fermi energy E_F is calculated in all cases. Our results are compared with those obtained by other authors. The band gap at N is very small for both metals, except when all model potential parameters are increased considerably (50% to 100%).     

Bestimmung der Homogenität von Legierungen mittels Autoradiographie and Aktivierungsanalyse

An für Konstruktionselemente verwendente verwendete Legierungen werden in Abhängigkeit von ihrer Verwendung folgende Anforderungen gestellt: hole Festigkeitskoeffizienten, erhöhte Temperaturbeständigkeit, erhöhte Korrosionbeständigketi gegen Chemikalien, erhöhte Verschleißbeständigkeit u. a. Chemische Heterogenität ist Ursache für Korrosionserscheinungen, Einleitung ungünstiger Reaktionen sowie Herabsetzung der örtlichen Reibfestigkeit und bewirkt damit eine Erniedrigung der Güteeigenschaften der Legierung. Einer der grundsätzlichen Wege, diesen Erscheinungen vorzubeugen, ist ein möglichst hoher Homogenitätsgrad der Legierung.     

Chemical constituents,Antibacterial and Acetylcholine esterase inhibitory activity of Cupressus macrocarpa leaves

Abstract

The chemical constituents of Cupressus macrocarpa were investigated. A new neolignan glycoside (1) in addition to nine known compounds were isolated. The acetylcholinesterase (AChE) inhibitory activity and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) of different fractions and isolates of C. macrocarpa were evaluated. The light petroleum fraction showed the highest activity in both assays with IC₅₀ value of 88.79 µg/ml and 152.58 µg/ml for the AChE inhibitory activity and MRSA antibacterial activities, respectively. Weak to moderate activity were detected for the isolated compounds.     

SYNTHESIS OF PYRIDAZOTHIENOTHIAZINE AND PYRIMIDOTHIENOPYRIDAZINES

Abstract

3-amino-4,5-diphenylthieno[2,3-c]pyridazine-2-arylcarboxamide 2 underwent cyclization with triethyl orthoformate and with nitrous acid to give the pyrimidothienopyridazines 3a-c, 4b respectively. 3-amino-4,5-diphenylthieno[2,3-c] pyridazine-2-carbohydrazide 6 reacted with aromatic aldehydes to give the corresponding carbohydrazones 7a-c. Compound 7 reacts with triethyl orthoformate, acetic anhydride or with CS₂/pyridine to produce pyrimidothienopyridazines 8,9 and pyridazothienothiazine 11.     

Madelung constants of the superlattices of the laves phases

The Madelung constants of all possible superlattices of the Laves phases are calculated using a modified form of the Ewald-Fuchs method.     

Aus der Praxis Ein Verfahren zur direkten Messung radioaktiv markierter Verunreinigungen an großen,festen Metallproben

A measure of functionality of agricultural sower is the layout of grains sown in the soil and labelled by radioisotope a method. To determine the precise position of the grains which are sown is a figure of merite. To resolve the problem, a detection system with focusing multihole collimator was used. A probe with collimator travelled on a self-propelled carriage. The detector pulses were ratio transmited to the field isotope lab. To label the grains of cereals, cucumber and beet the isotope ^99mTc obtained from Mo–Tc generator was applied.     

The minimax approach for a class of variable order fractional differential equation

This paper introduces an approximate solution for Liouville‐Caputo variable order fractional differential equations with order 0 < α(t) ≤ 1 . The solution is adapted using a family of fractional‐order Chebyshev functions with unknown coefficients. These coefficients have been obtained by using an optimization approach based on minimax technique and the least pth optimization function. Several linear and nonlinear fractional‐order differential equations are discussed using the proposed technique for fixed and variable order fractional‐order derivatives. Moreover, the response of RC charging circuit with variable order fractional capacitor is studied for different cases. Several comparisons with related published techniques have been added to illustrate the accuracy of the proposed approach.