Current design codes for fire resistance of structures are based on isolated member tests subjected to standard fire conditions. Such tests do not reflect the behaviour of a complete building under either normal temperature or fire conditions. Many aspects of behaviour occur due to the interaction between members and cannot be predicted or observed in tests of isolated elements. Performance of real structures subject to real fires is often much better than that predicted from standard tests due to structural continuity and the provision of alternative load paths. This paper reports on the results of a collaborative research project (Tensile membrane action and robustness of structural steel joints under natural fire, European Community FP5 project HPRI-CV 5535) involving the following institutions: Czech Technical University (Czech Republic), University of Coimbra (Portugal), Slovak Technical University (Slovak Republic) and Building Research Establishment (United Kingdom). It consists of an experimental programme to investigate the global structural behaviour of a compartment on the 8-storey steel-concrete composite frame building at the Cardington laboratory during a BRE large-scale fire test, aimed at the examination of the temperature development within the various structural elements, the corresponding (dynamic) distribution of internal forces and the behaviour of the composite slab, beams, columns and connections. r
In this paper we consider the initial boundary value problem of the Navier-Stokes system with various types of boundary conditions. We study the global-in-time existence and uniqueness of a solution of this system. In particular, suppose that the problem is solvable with some given data (the initial velocity and the external body force). We prove that there exists a unique solution for data which are small perturbations of the previous ones.Mathematics Subject Classification. 35Q30, 35D05.
Abstract:In this paper we consider the system of the non-steady Navier-Stokes equations with mixed boundary conditions. We study the existence and uniqueness of a solution of this system. We define Banach spaces X and Y , respectively, to be the space of "possible" solutions of this problem and the space of its data. We define the operator N : X → Y and formulate our problem in terms of operator equations. Let u ∈ X and G P u : X → Y be the Frechet derivative of N at u. We prove that G P u is one-to-one and onto Y . Consequently, suppose that the system is solvable with some given data (the initial velocity and the right hand side). Then there exists a unique solution of this system for data which are small perturbations of the previous ones. Next result proved in the Appendix of this paper is W 2,2 -regularity of solutions of steady Stokes system with mixed boundary condition for sufficiently smooth data.
Microstructure development and thermal behavior of ground talc mineral samples (from locality Puebla de Lillo, Spain) was characterized by X-ray diffraction, scanning electron microscopy(SEM),surface area measurements differential thermal analysis, thermogravimetry and emanation thermal analysis (ETA).A vibratory mill and grinding time 5 min. was used to prepare the ground talc sample. It was found that grinding caused an increase in the surface area of the natural talc from 3 m2g-1 to 110 m2g-1. A decrease of particle size after sample grinding was observed by SEM. The increase of structure disorder of the ground sample and the crystallite size reduction from 40 to 10 nm were determined from the XRD results. ETA results revealed a closing up of surface micro-cracks and healing of microstructure irregularities on heating in the range 200-500ºC of both un-ground and ground talc samples. For the ground talc sample a crystallization of non-crystalline phase into orthorhombic enstatite was characterized as by a decrease of radon mobility in the range 785-825ºC and by a DTA exothermal effect with the maximum at 830ºC. ETA results were used for the assessment of transport properties of the talc samples on heating
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