The impact of climate change policy on competition in the air transport industry

This paper examines how climate change policy can impact on competition, prices and profitability in the air transport industry. It begins with an outline of the climate change policies that have been suggested, and it gives particular attention to the inclusion of air transport in an emissions trading scheme (ETS).This is likely to prove an important policy direction, with the EU, Australia and New Zealand all planning to include air transport in their ETSs. The scope for airlines to reduce their emissions intensity in the short run and long run is examined- it is concluded that the scope in the short run is quite limited. After this, the application of the emissions trading schemes of the EU, Australia and New Zealand to air transport is discussed, and the possible impacts on air fares are assessed. Allowance is made for the cost of permits for both direct and indirect emissions. The impacts of climate change policies, such as carbon taxes or requirements to purchase emissions permits, on airline competition, prices and profitability are analysed next. Impacts differ according to market structure- whether airline city pair markets are competitive, monopolistic or oligopolistic. They also depend on the time scale- airlines are unlikely to be able to pass on the full cost of their permits to their passengers in the short run, though in the long run, it is likely that airlines will exit from some city pairs, and this will enable to remaining airlines to raise their fares and restore their profitability. This may not occur in markets constrained by airport slots or capacity limits imposed in air services agreements on international routes, though the airlines' problems are not likely to be as severe as has been suggested. If permits are provided free of charge to airlines, fares should still rise in the long run, assuming that airlines are profit maximisers and factor in the opportunity cost of the permits they obtain free. However even if airlines do this, there can be cases where fares do not rise by as much as they would if permits have to be purchased, because the operation of the ETS may discourage exit from markets. If airlines do not act as profit maximisers, air fare increases will be limited, and airlines will have the scope to cross subsidise less profitable routes. The limited evidence on airlines' use of free inputs (such as airport slots) is examined to obtain insights into whether airlines do indeed maximise their profits- this evidence is inconclusive. Finally the application of an ETS to international air transport is considered - this can give rise to issues of competitive non-neutrality, even when permits are sold

Yield Measures for Special-Interest Australian Inbound Tourism Markets

Different tourism stakeholders mean different things by ‘yield’ and this presents a barrier to communication and policy discussion. Primarily, this paper provides an overview of different concepts of yield. It also operationalizes several of these measures using inbound tourism expenditure data for Australia so that the origin markets and market segments identified as generating high yields under the various measures can be compared. The paper further identifies the manner in which the concept of yield can be broadened to embrace sustainable yield by incorporating measures of environmental and social impact. It concludes with a discussion of the policy implications of the study

Imaging correlates of molecular signatures in oligodendrogliomas.

Molecular subsets of oligodendroglioma behave in biologically distinct ways. Their locations in the brain, rates of growth, and responses to therapy differ with their genotypes. Retrospectively, we inquired whether allelic loss of chromosomal arms 1p and 19q, an early molecular event and favorable prognostic marker in oligodendrogliomas, were reflected in their appearance on magnetic resonance imaging. Loss of 1p and 19q was associated with an indistinct border on T(1) images and mixed intensity signal on T(1) and T(2). Loss of 1p and 19q was also associated with paramagnetic susceptibility effect and with calcification, a common histopathological finding in oligodendrogliomas. These data encourage prospective evaluation of molecular alterations and magnetic resonance imaging characteristics of glial neoplasms

High temperature particle deposition with gas turbine applications

This thesis describes validated improvements in the modelling of micron-sized particle deposition within gas turbine engine secondary air systems. The initial aim of the research was to employ appropriate models of instantaneous turbulent flow behaviour to RANS CFD simulations, allowing the trajectory of solid particulates in the flow to be accurately predicted. Following critical assessment of turbophoretic models, the continuous random walk (CRW) model was chosen to predict instantaneous fluid fluctuating velocities. Particle flow, characterised by non-dimensional deposition velocity and particle relaxation time, was observed to match published experimental vertical pipe flow data. This was possible due to redefining the integration time step in terms of Kolmagorov and Lagrangian time scales, reducing the disparity between simulations and experimental data by an order of magnitude. As no high temperature validation data for the CRW model were available, an experimental rig was developed to conduct horizontal pipe flow experiments under engine realistic conditions. Both the experimental rig, and a new particulate concentration measurement technique, based on post test aqueous solution electrical conductivity, were qualified at ambient conditions. These new experimental data compare well to published data at non-dimensional particle relaxation times below 7. Above, a tail off in the deposition rate is observed, potentially caused by a bounce or shear removal mechanism at higher particle kinetic energy. At elevated temperatures and isothermal conditions, similar behaviour is observed to the ambient data. Under engine representative thermophoretic conditions, a negative gas to wall temperature gradient is seen to increase deposition by up to 4.8 times, the reverse decreasing deposition by a factor of up to 560 relative to the isothermal data. Numerical simulations using the CRW model under-predict isothermal deposition, though capturing relative thermophoretic effects well. By applying an anisotropic Lagrangian time scale, and cross trajectory effects of the external gravitational force, good agreement was observed, the first inclusion of the effect within the CRW model. A dynamic mesh morphing method was then developed, enabling the effect of large scale particle deposition to be included in simulations, without continual remeshing of the fluid domain. Simulation of an impingement jet array showed deposition of characteristic mounds up to 30\% of the hole diameter in height. Simulation of a passage with film-cooling hole off-takes generated hole blockage of up to 40\%. These cases confirmed that the use of the CRW generated deposition locations in line with scant available experimental data, but widespread airline fleet experience. Changing rates of deposition were observed with the evolution of the deposits in both cases, highlighting the importance of capturing changing passage geometry through dynamic mesh morphing. The level of deposition observed, was however, greater than expected in a real engine environment and identifies a need to further refine bounce-stick and erosion modelling to complement the improved prediction of impact location identified in this thesis