Evaluation of the solute transport characteristics of surcharged manholes using a RANS solution

Urban drainage networks contain a large number of structures; the most common of which is a manhole. Previous studies investigating solute transport through manholes identified a threshold level of surcharge at which the hydraulic conditions in the manholes sharply altered. At high levels of surcharge, a dead zone formed above the main jet, potentially retaining solute for later discharge. This phenomenon could have significant impacts on the results obtained from 1D urban drainage network models which only consider pure advection. Previous research (including other CFD based studies) concentrated on steady flow conditions through these structures which are not thought to be representative of the dynamic flow conditions experienced in practice. During large storm events, the capacity of combined sewer networks may be exceeded. This leads to the discharge of untreated sewage to receiving watercourses. Discharges such as these are governed by legislation and, therefore, an understanding of pollutant transfer through urban drainage networks is required. Using existing laboratory and Computational Fluid Dynamics (CFD) data, this study produced a primary and secondary validated methodology for meshing and modelling manholes using CFD. This was then extended to free-surface multiphase modelling allowing for more realistic unsteady conditions to be considered. This included an in-depth comparison of suitable turbulence models and solute-modelling options. It was found that, whilst it was possible to model multiphase free-surface flow within such a structure, it was unnecessarily computationally expensive as temporal changes in the flow field are rapid when compared with a practical time-step for use with 1D models. The validated modelling methodology was then used to recreate the original study that identified the hydraulic threshold. This included a selection of manholes with a range of inlet to manhole diameter ratios. However, this was extended further to include manholes with a ratio less than five (commonly found in UK sewer systems). It was shown that the hydraulic threshold broke down below this limit, removing the need for this to be modelled in 1D systems.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Influence of the OH groups of hydroxylated rutile (110) surface on the Lewis acidity: an investigation of CO adsorption by quantum-mechanical simulations.

International audienceThe adsorption of carbon monoxide on the clean and hydroxylated rutile (110) surface has been investigated by a periodic approach at DFT/B3LYP level. The hydroxylated surface has been modelled by considering both terminal and bridging OH groups. The variation of the electrophilicity of the Lewis acid site near these groups has been evaluated by taking into account the adsorbate-substrate distance, the magnitude of the interaction energy and the blue-shift of the adsorbed CO stretching frequency. The obtained results suggest that the electrophilicity increases in proximity of OH terminal groups, while decreases near the OH bridging ones

CH2ClF adsorbed on TiO2: study of the adsorbate-substrate interaction by IR spectroscopy and DFT calculations

Codice rivista: E20272

Moving ashore? : Greek shipowners, state corporatism and the Europeanisation of maritime transport

As the European Commission muscled in the national configuration and domestic actors engaged with the EU institutions, the purpose of this dissertation is to explore the impact of Europeanisation on the state corporatist arrangement encompassing the Greek state and the shipowners. The central argument is that although there is evidence of the reshaping of the relations between the state and Greek shipowners, the direction of change varies across industry segments and is contingent on four conditions. Firstly, it is contingent on the nature of the Greek state and its ability to exercise 'integrated leadership'. Secondly, the domestic actors recognise and act upon the incongruence between EU initiatives and existing domestic or international policies. Thirdly, the shipowners possess the capacity to exit the domestic configuration through capital mobility. Fourthly, alongside the shipowners, the presence of influential formal or factual veto points in the domestic institutional arrangement. The argument made is sustained through the analysis of the impact of Europeanisation on the relations between the Greek state and shipowners in two case studies. The first case study is devoted to ocean-going shipping and the growing EU competence in maritime safety regulation, concentrating on the accelerated phasing- out of single-hull tankers and the constitution of criminal sanctions for ship-source pollution. The Greek ocean-going shipowners in consultation with the incumbent Greek governments mobilized at every possible level to halt or amend the EU initiatives. As a result, there is evidence of the reinforcement of state corporatism which is contingent on the unitary nature of the Greek state, the absence of integrated leadership, the incompatibility between EU and international policies, the capital mobility and ensuing structural power of ocean-going shipowners and the weakness of the other formal or factual veto points in the domestic political process. The second case study concentrates on the coastal shipping sector and EU measures to abolish the cabotage trades across the member states. The coastal shipowners, the incumbent Greek governments and the island communities engaged politically with the EU institutions in advancing their interests. In this instance, there is evidence of the loosening of the state corporatist arrangement between the Greek state and the coastal shipowners. In spite of the unitary nature of the state, the lack of 'integrated leadership': and the incongruence between the EU and domestic policies, the coastal shipowners were more embedded at the national level and contended with an influential factual veto point in the form of the island communities.EThOS - Electronic Theses Online ServiceGBUnited Kingdo