No description available.

Railway vehicles are fitted with coned wheels to provide a measure of stability, but it can be shown that since the forces between wheel and track are non-conservative, dynamic instability occurs at a certain critical speed. Under these conditions the wheelsets sway from side-to-side of the, track with the flanges of the wheels contacting the rails. This can lead to derailment when the wheel climbs up the rail and eventually jumps off. The forces which exist between wheel and rail are due to the phenomenon known as "creepage", and various theories exist which predict these forces in the plane of the contact area. An investigation has been carried out into these theories with the railway wheelset problem in view, particularly the flange contact case. It is possible, by assuming small displacements which avoid flange contact, to carry out a linearised study of the lateral dynamics of a wheelset, but the presence of the wheel flanges introduces a nonlinearity into the problem. A mathematical model of a wheelset and track has been defined based on real wheels with a "worn" tyre profile and real track. Computer programs have been written which calculate the contact points when the wheelset is displaced laterally and yawed by various amounts, including flange ,contact conditions. Up to three contact points can exist between the wheelset, and track. Forces in the contact areas have been calculated using the various theories assuming the wheelset to be rolling along the track a ta constant velocity in a displaced position. These forces have been manipulated to give the total forces and, moments on the wheelset and are presented for various vertical load distributions and for various angular and lateral displacements of the wheelset from its central position. Although theories exist which predict the forces for flange type contact, i. e. very elongated contact ellipse with a large amount of spin present, it became apparent during the course of the investigation that very little experimental evidence was available for such conditions. As a result a roller rig was built to provide this data, and measurements were made of the lateral force due to various amounts of lateral creep and spin on elongated contact ellipses. Results from these tests have been compared with the available theories and show reasonable agreement.

No description available.

Water treatment approaches for pharmaceutically active compounds (PhACs) are restricted by the chemically-variable nature of the PhACs themselves, each successful in treating only a small number; or the adaptability or expense of the treatment system. Minimal study has taken place concerning novel, affordable, amendable treatment media that can be employed on numerous scales and water types, with the potential to treat a variety of PhACs and other water contaminants. This study evaluates the removal of a suite of environmentally relevant pharmaceuticals from water in response to contact with reactive media and/or natural organic matter. Experiments were conducted with batch samples containing a media of interest in simulated ground water spiked with carbamazepine, caffeine, naproxen, gemfibrozil, ibuprofen, sulfamethoxazole and clofibrate, each at an environmentally relevant concentration of 2-2.5 ??g l-1. Media investigated included: Stelco-BOF slag (STB), woodchips (WC), Borden sand (BDS), zero valent iron (ZVFe), and granular activated carbon (GAC). Water samples were analyzed for basic water quality parameters and pharmaceutical concentrations were calculated by internal and external calibration of HPLC-MS/MS results. Calculated pharmaceutical removal efficiencies were based upon percent changes in concentration between initial and final measurements. Pharmaceutical removal was observed for all investigated media, with success varying between media and pharmaceutical types. The greatest percent removal, of >99.88% was observed for all PhACs, with concentrations dropping below the limits of detection (LOD) of 3-189 ng l-1, in GAC and ZVFe-GAC mixtures; the smallest percentage removal when considering all media, of 0.0%, was exhibited by ibuprofen and naproxen in STB, BDS and WC samples. The greatest removal was observed within the first 24 hours for the majority of the drugs that showed measurable removals. Results also indicated that the addition of activated carbon to zero valent iron may enhance the reactivity and/or lifespan of the media.

No description available.

No description available.

No description available.

Structures exhibit coupled torsional and translational responses to earthquake ground motion input if their centres of floor mass and their centres of resistance do not coincide. However, torsional motions may occur even in nominally symmetric structures due to accidental eccentricity and torsional ground motions. The sources giving rise to accidental eccentricity include the difference between the assumed and actual distributions of mass and stiffness, asymmetric yielding strength, non-linear patterns of force-deformation relationships, and differences in coupling of the structural foundation with the supporting soil. Symmetric and regular buildings that are properly designed have a much higher ability to survive a strong earthquake event than asymmetric buildings and their response to earthquake loading is far more straightforward to predict and design for. On the other hand, even though the response of asymmetric buildings is more unpredictable, designers still have to compromise structural regularity to accommodate functional and aesthetic needs. As a result, serious and widespread damage associated with structural asymmetry has been observed repeatedly in past major earthquakes. In the first studies examining torsional effects in buildings, attention was focused on the elastic structural behaviour of single-storey buildings and the main purpose was to achieve a complete understanding of the effects of mass and stiffness eccentricities and to evaluate them by simple static models. However, as the response of real structures is mainly inelastic, these studies gave poor information on torsional behaviour and interest has moved towards non-linear response studies. In an effort to clarify some of the issues influencing the inelastic torsional response of multistorey asymmetric structures, this thesis presents a series of coherent parametric investigations. These investigations include comparing the response of various reference models to the performance of code-designed torsionally unbalanced structures. An extensive parametric investigation of torsionally responding structures designed as stipulated by a selection of major earthquake building codes is presented and the adequacy of the static torsional provisions is assessed for a wide range of structural configurations and parameters. Detailed investigations of torsionally asymmetric structures incorporating frame elements oriented along both orthogonal axes of the structure are also conducted and the effect of including the second earthquake component to simultaneously excite the structural models is quantified. The relative merits and deficiencies of each code provision are discussed and a new proposed optimised method is tested. All fundamental conclusions from the investigations conducted are presented and various topics for further research are proposed, which are considered to be both necessary and pertinent for increasing and refining the knowledge and understanding the complex behaviour of multistorey torsionally asymmetric buildings.

No description available.

No description available.