Integrability of the generalised Hill problem

Nonlinear Dynamics - We consider a certain two-parameter generalisation of the planar Hill lunar problem. We prove that for nonzero values of these parameters the system is not integrable in the...     

Synthesis of phenylene–silylene–ethylene polymers via transition metal complex catalyzed hydrosilylation polymerization

New phenylene–silylene–ethylene polymers have been successfully synthesized using platinum–divinylsiloxane or rhodium and iridium siloxide complex‐catalysed polyhydrosilylation of divinylsubstituted carbosilanes with dihydrocarbosilanes or intermolecular hydrosilylation of new hydrovinylcarbosilane. Polycarbosilanes have been obtained with high molecular weights. They seem to be potential parent substances for future applications as preceramic and membrane materials. Copyright © 2005 John Wiley & Sons, Ltd.     

Application of Thermal Analysis in Radiocarbon Dating

Thermal analysis combined with mass spectrometry was applied to radiocarbon dating procedures (age determination of carbon containing samples) to determine the optimal temperature range for the reduction of CO₂ over metallic cobalt of various particle sizes. Experiments were carried out to show the different catalytic activities of cobalt of particle sizes 1, 1–45 and 44 μm. The morphology of the cobalt samples and the deposited carbon were investigated. The quantification of CH₄ and CO formed during the reduction of CO₂ was done by means of pulse thermal analysis. This revised version was published online in July 2006 with corrections to the Cover Date.     

On the new procedure for the determination of surface conditions in thin films with internal layer inhomogeneity

A method for determining the surface conditions on both surfaces of the film, based in the thickness dependence of localized states is proposed.     

Differential Galois obstructions for non-commutative integrability

We show that if a holomorphic Hamiltonian system is holomorphically integrable in the non-commutative sense in a neighbourhood of a non-equilibrium phase curve which is located at a regular level of the first integrals, then the identity component of the differential Galois group of the variational equations along the phase curve is Abelian. Thus necessary conditions for the commutative and non-commutative integrability given by the differential Galois approach are the same.     

Optimisation of pneumatic circuit aimed at improving the vibro-isolation properties of seat suspension

The object of a numerical simulation and optimisation is the seat with a visco-elastic passive suspension, with improved vibro-isolation properties by means the multi-criteria optimisation. Basing on the verified passive seat suspension model, a modification of the pneumatic circuit in order to help the working machines operators against vibration is considered. The root mean square (RMS) acceleration measured at the seat and the maximum relative displacement of the seat suspension are minimised as the chosen vibro-isolation criteria. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Modelling of working machines seat suspension with an air-spring and hydraulic shock-absorber

For the purpose of this paper, an exemplary seat suspension system is modelled and simulated numerically. The system consists of a shear guidance mechanism of a suspended seat, an air-spring, a hydraulic shock-absorber and end-stop buffers. As results of computer simulations, the power spectral densities of acceleration and the transmissibility functions of seat suspension are evaluated with respect to results measured experimentally. The verification of simulation model is performed in the basis of Seat Effective Amplitude Transmissibility factor (SEAT) and the maximum relative displacement of suspension system. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Flame synthesis of nanocrystalline ceria-zirconia: effect of carrier liquid

Spraying cerium and zirconium precursors dissolved in carboxylic acids into a methane-oxygen flame resulted in well-structured nanocrystals of ceria-zirconia mixed oxides with high temperature stability and surface area.     

On the new dynamical boundary conditions for spin wave resonance in multilayer ferromagnetic films

A new microscopic approach to spin wave resonance in multilayer ferromagnetic films is proposed. An exact procedure of solving the eigenvalue problem corresponding to inhomogeneous films by its formal reduction to the problem of effective homogeneous thin films with the well-defined dynamical boundary conditions is introduced.     

Determination of the kinetic parameters of the multi-stage thermal decomposition of solids under non-isothermal conditions by the non-linear estimation approach

The activation energy of decomposition of aluminium hydroxidevs. weight loss was estimated from thermogravimetric data collected over a wide range of heating rates, without resorting to the model of the reaction mechanism.These activation energy values were subsequently used to distinguish individual dehydration stages and to determine the best models of the reaction kinetics for these stages.Finally, the overall decomposition model was formulated, and its parameters were determined by the non-linear estimation approach.

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Zusammenfassung Die Aktivierungsenergie der Zersetzung von Aluminiumhydroxid wurde in Abhängigkeit vom Gewichtsverlust aus einen weiten Bereich von Aufheizgeschwindigkeiten umfassenden thermogravimetrischen Daten gesammelt, ohne auf das Modell des Reaktionsmechanismus einzugehen.Diese Werte der Aktivierungsenergien wurden daraufhin zur Unterscheidung einzelner Dehydratisierungsstufen und zur Bestimmung der besten Modelle der Reaktionskinetik dieser Stufen eingesetzt.Schließlich wurde ein allgemeines Zersetzungsmodell formuliert und seine Parameter durch nichtlineare Schätzungsnäherung bestimmt.

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Résumé On a estimé l'énergie d'activation de la décomposition de l'oxyde d'aluminium en fonction de la perte de poids à partir de données thermogravimétriques obtenues avec un large intervalle de vitesses de chauffage, sans avoir recours au modèle du mécanisme de la réaction. On a utilisé ensuite ces valeurs de l'énergie d'activation pour distinguer les étapés individuelles de la déshydratation et pour déterminer les meilleurs modèles de cinétique réactionnelle correspondant à celles-ci.Enfin, on a formulé un modèle général de décomposition et déterminé ces paramètres par approximations non linéaires.

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