A semi‐implicit numerical model for urban drainage systems

In this paper, a semi‐implicit numerical model for one‐dimensional urban drainage networks is formulated in such a fashion as to intrinsically account for arbitrary cross sections, for the occurrence of dry areas, for free surface, and for pressurized flows. The governing differential equations are discretized with a consistent mass conservative scheme that naturally applies to all flow regimes. The resulting mildly nonlinear system, at every time step, is efficiently solved with a converging, properly devised, nested Newton‐type algorithm. It will be shown that with the proposed semi‐implicit model, high accuracy can be achieved at a moderate computational cost. Copyright © 2013 John Wiley & Sons, Ltd.     

One Pot Synthesis of 1-Chloro-2-Chlorocarboxy-4H-Quinolizin-4-One and Its Derivatives

Condensation of 2-pyridine acetic acid with thionyl chloride under reflux conditions generates the title compound in one step with >95% yield. Its reactivity toward alcohols and amines were investigated. All of the derivatives were characterized by NMR and MS analysis. One of its derivatives, 1-chloro-2-methoxycarboxy-4H-quinolizin-4-one, 5, was also characterized by X-ray diffraction studies.     

Sestak–Berggren function in temperature-programmed reduction

From the peculiarities of Temperature-programmed reduction (TPR) method and using the Sestak–Berggren conversion function, we describe first the TPR curve simulation procedure. The influence of the Sestak–Berggren exponents on the TPR peak maximum and shape is demonstrated, by analyzing several synthetic TPR profiles. Finally, the kinetic parameters of Au/CeO₂ promoted with yttrium as well as those of Au/CeO₂–Al₂O₃ promoted with V₂O₅ are discussed.     

Plastic flow for axisymmetric-tension specimens with necking

Plastic deformation of a tension specimen bounded by a curved surface of revolution is considered. Such a configuration may occur, for example, as a result of necking. The specimen material satisfies the Tresca yield condition and the associated flow rule. Approximate solutions for the stress distribution in the neck were examined in [6]. The extension of notched bars was investigated by numerical and graphic methods in [2, 4]. Below, the problem is solved analytically for a sufficiently smooth neck; a small degree of nonuniformity of the plastic properties is taken into account.     

A Dilatometric Investigation of the Thermal Compaction of Ferrite Powders Prepared by Coprecipitation

The authors report on a non-isothermal kinetic investigation (at constant heating rate) of the sintering of manganese and nickel-zinc ferrite powders prepared by coprecipitation. The kinetic results point to the thermal compaction of the powders, which occurs mainly in the intermediate stage of sintering. A comparative study was performed in order to determine the influence of the sample characteristics (such as chemical nature, density and shape) and the heating rate on the kinetics and mechanism of the compaction. This revised version was published online in August 2006 with corrections to the Cover Date.     

Steady-State Approximation. 5

The example of the sequence of reactions

Design and study of Bi[1,8]naphthyridine ligands as potential photooxidation mediators in Ru(II) polypyridyl aquo complexes

A series of 3,3'-polymethylene-bridged bi[1,8]naphthyridine (binap) ligands, 3a-c, are complexed with Ru(II) to afford [Ru(tpy)(3a-c)(H(2)O)](2+) where an uncomplexed nitrogen on 3a-c is situated so it can form a H-bond with the coordinated water. An additional complex involving [Ru(4'-NMe(2)tpy)(3b)(H(2)O)](2+) is also prepared. X-ray analyses of the [Ru(tpy)(3a,c)(H(2)O)](2+) complexes indicate well-organized H-bonds even when the binap is nonplanar. In an attempt to realize photooxidation, the effects of light, varying potential, and pH were examined. A Pourbaix diagram indicated that the oxidation potential decreased by approximately 0.5 V in the pH range of 1.9-11.6. The lowest-energy electronic absorption for the binap complexes involves the metal-to-ligand charge transfer to the binap ligand and is sensitive to ligand planarity. The absorbance shifted to a lower energy as the auxiliary ligand became a better donor (4'-NMe(2)tpy) or as the water was deprotonated. Acetonitrile was found to displace water most easily for the complex of 3c, where the ligand is the least planar. Despite promising features, photooxidation of the bound water was not observed.     

On the changes induced by laser irradiation in CrO3 and K2Cr2O7 powders

Some results concerning the CO₂ laser induced changes in CrO₃ and K₂Cr₂O₇ powders, obtained from X-ray diffractograms and thermoanalytical curves are presented.     

Pyridylsilanes in the synthesis of heterocycles (review)

The desilylation of pyridylsilanes and pyridylmethylsilanes is one of the most characteristic reactions of organosilicon derivatives of pyridine, and it has been shown to be possible to utilize this reaction in organic synthesis. In many instances, desilylation affords difficultly-accessible pyridine derivatives, which have also been synthesized by insertion of aldehydes into the Si-C bond in pyridylsilanes and reactions of organosilicon pyridinium compounds. 2-Trimethylsilylmethylpyridine has been found to undergo the largest number of reactions leading to the formation of a variety of compounds containing the pyridine ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 5–13, January, 1987.