Polarographische Untersuchungen von aus Cadmium(II) und Propylendiamin in wäßrigem Dimethylformamid entstandenen Komplexen

The reduction of Cd(II) in propylenediamine was found to be reversible and diffusion controlled. The complexes of Cd(II) with propylenediamine in 25%, 50%, and 75% dimethylformamide have been studied polarographically using theDeFord andHume's treatment as extended byIrving. Increase in the stability constants was observed with increase in dimethylformamide percentage. The percentage composition of the various complexed and uncomplexed species in 25% and 50% dimethylformamide are presented.     

A theoretical study of solvation energies of FCH2COO−, FCH2COOH,and F2CHCOO−

A continuum and a discrete-continuum models are used to determine the solvation energies of FCH₂COO^?, FCH₂COOH, and F₂CHCOO^?. For the anions, the continuum model provides results closer to the experiment, while for the acid, the addition of one water molecule improves the continuum-only energy.     

Enantioselective synthesis of (8S,13S,14R)-7-oxa-estra-4,9-diene-3,17-dione

The first enantioselective synthesis of (8S,13S,14R)-7-oxa-estra-4,9-diene-3,17-dione with the trans-C/D ring junction is described. Key features of the synthesis include Ag₂O-mediated C-O bond formation, thermodynamically controlled axial-equatorial inversion, one-pot of halogen exchange and Co/Cr-mediated C-C bond formation, and intramolecular aldol condensations.     

Reaction of nitriles under acidic conditions. Part VII. Study on the reaction of o-aminonitriles with cyanamides to synthesize 2,4-diaminothieno[2,3-d]pyrimidines

The reaction of N-arylcyanamides with thiophene o-aminonitriles under the influence of dry hydrogen chloride gas yields a mixture of two products. The major product has been identified as 2-amino-3-aryl-4-iminothieno[2,3-d]pyrimidine and the minor as 2-amino-3-arylthieno[2,3-H]pyrimidin-4(3H)-one.     

Thermal ignition studies on metallized fuel-oxidizer systems

The thermal ignition behaviour of various mixtures of organic fuels, magnesium and ammonium nitrate (AN) has been examined by differential thermal analysis technique. It has been observed that the thermal decomposition/ignition of organic fuel-AN mixtures is modified significantly in the presence of magnesium metal. The decomposition characteristics of the binary mixtures of AN with various metals indicate the specific action of magnesium and zinc in lowering the decomposition temperature. A possible explanation for the low temperature decomposition is given in terms of the solid state reaction causing the fusion of AN which further reacts with the metal resulting in a highly exothermic reaction.

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Zusammenfassung Mittels DTA wurde das thermische Initiierungsverhalten verschiedener Gemische aus organischen Brennstoffen, Magnesium und Ammoniumnitrat (AN) untersucht. Es wurde festgestellt, daß die thermische Zersetzung/Initiierung von Gemischen aus organischen Brennstoffen und AN durch die Gegenwart von metallischem Magnesium bedeutsam beeinflußt wird. Die Zersetzungscharakteristiken binären Gemische aus AN und verschiedener Metalle zeigen eine spezielle Wirkung von Magnesium und Zink bei der Herabsetzung der Zersetzungstemperatur. Eine mögliche Erklärung für die Zersetzung bei niedrigerer Temperatur kann in Bezug auf die Festkörperreaktion gesehen werden, die das Schmelzen von AN verursacht, welches dann mit dem Metall stark exotherm reagiert.

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Use of 2-amino-3-hydroxypyridine as a complexing agent for the determination of copper by flame atomic absorption spectrometry and its application to complex sulphide ore

Copper has been determined in ore samples by FAAS after preceding precipitation with 2-amino-3-hydroxypyridine at pH 10. Standard deviations of ±0.11% were obtained for 14% Cu.     

Massively time-parallel,approximate simulation of loss queueing systems

A time-parallel simulation obtains parallelism by partitioning the time domain of the simulation. An approximate time-parallel simulation algorithm named GG1K is developed for acyclic networks of loss FCFSG/G/1/K queues. The GG1K algorithm requires two phases. In the first phase, a similar system (i.e. aG/G/1/ queue) is simulated using the GLM algorithm. Then the resultant trajectory is transformed into an approximateG/G/1/K trajectory in the second phase. The closeness of the approximation is investigated theoretically and experimentally. Our results show that the approximation is highly accurate except whenK is very small (e.g. 5) in certain models. The algorithm exploits unbounded parallelism and can achieve near-linear speedup when the number of arrivals simulated is sufficiently large.