Effect of trace dissolved oxygen on the cathodic kinetics of carbon dioxide corrosion of carbon steel.

Summary: The corrosion of carbon steel in carbon dioxide saturated brine solutions is controlled by a mixed activation-mass transfer process in the cathodic reaction mechanism. Cathodic polarisation curves of carbon steel in carbonic acid solutions exhibit a limiting current behaviour that is dependent on the rate of mass transfer. In studies using the jet impingement technique, the magnitude of this limiting current behaviour has been found to be strongly affected by the presence of trace levels of dissolved oxygen. This paper presents a theoretical assessment of the mass transfer limited cathodic current to illustrate the pronounced effect of dissolved oxygen contamination <15ppb. Discussion is presented regarding the implications of dissolved oxygen contamination on the interpretation of the mechanism of carbon dioxide corrosion

Flow Dependence of Carbon Dioxide Corrosion Using Short Electrodes by Jet Impingement

The jet impingement technique is a valuable methodology for the evaluation of carbon dioxide corrosion and inhibition under high flow velocities. This technique commonly employs short electrodes that remain within a region of the developing diffusion boundary layer induced by the reactively corroding surface. The employment of such electrodes has been associated with the poor correlation of corrosion rates determined from field and laboratory measurements by various apparatus. This paper presents an investigation into the flow relationship of the carbon dioxide corrosion mechanism in non-scaling synthetic brine solutions at 30 C with a carbon dioxide partial pressure of 1.88 bar. The effect of the developing diffusion boundary layer on the corrosion rate and its dependence on the flow velocity is investigated by jet impingement using dissimilar electrode lengths in the flow direction.It is shown that the measured corrosion rate is dependent on the state of development of the diffusion boundary layer with a relationship that is contrary to the average rate of mass transfer. A more developed diffusion boundary layer exhibits a greater rate of carbon dioxide corrosion at a lower average mass transfer than in a developing diffusion boundary layer with a higher average mass transfer. This phenomenon illustrates an antagonistic effect of the diffusion boundary layer on the mechanism of carbon dioxide corrosion that is likely to strongly influence the correlation of corrosion rates obtained using various laboratory apparatus and field applications

Monitoring criteria for priority chemicals leading to emission factors

The Water Framework Directive (WFD) 2000/60/EC, requires a coordinated approach to water management in respect of whole river basins with a view to protecting the high-status of waters where it exists, preventing any deterioration in the existing status of waters and achieving at least "good status" in relation to all waters. The EPA-funded Monitoring Criteria for Priority Chemicals Leading to Emission Factors aims to establish risk factors for priority substances (PS) & priority hazardous substances (PHS), which will assist in defining the monitoring programme in Ireland for WFD. Indicators are applied to monitored WWTP agglomerations to predict the relative risk of elevated PS/PHS loading to receiving waters across agglomerations over time. In Ireland, where the current state of knowledge and data availability (e.g. emission data from individual installations) is insufficient to support high resolution based models the project team have developed a simple, stochastic, risk-based model that can be applied across catchments to predict the relative risk of elevated PS/PHS loading to receiving water

Devising a risk index for priority substance emissions from WWTPs

A review was used to identify the major factors leading to priority substances (PS) & priority hazardous substances (PHS) loading from WWTPs, integrated and conceptualised into a basic conceptual model. The focus is on readily-available data relevant to major PS/PHS risk factors identified by conceptual modelling, developing appropriate indicators. Databases were compiled for Local Authority and EPA licensed discharges, and agglomeration traffic. Results from these databases were integrated into the risk model for agglomeration PS/PHS loading, combined with basic WWTP (e.g. capacity and treatment level) and agglomeration (e.g. population and area) data, and finally expressed as elevated risk in a national context following normalisation procedures

Licensing & treatment variability among WWTPs in the monitoring criteria for priority chemicals leading to emission factors project

A system for the licensing of waste water discharges from areas served by local authority sewer networks was introduced in 2007 and will require all WWTP to obtain a waste water discharge licence from the EPA by set dates depending on the population equivalent (PE) of the area served by the sewer network. The licensing gives effect to a number of EU Directives, imposing restrictions or prohibitions on the discharge of dangerous substances to receiving water bodies

A pragmatic multi-centre randomised controlled trial of fluid loading and level of dependency in high-risk surgical patients undergoing major elective surgery : trial protocol

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Priority and hazardous substances

The EU Water Framework Directive (WFD) (2000/60/EC) was transposed into Irish law in 2003 as the European Communities (Water Policy) The level of priority substances present in water bodies is most commonly judged against set environmental quality standards (EQSs) . These standards dictate the maximum allowable concentrations (MAC EQS) or range of concentrations (Annual Average or AA EQS) of specific pollutants allowed to ensure compliance with the EC guidelines. The EU WFD was transposed into Irish Law in 2003 and as such these EQS values now form the basis of priority substance water monitoring in Ireland

Policy drivers of farm succession and inheritance

peer-reviewedFarm succession and inheritance is increasingly considered a complex phenomenon which not only affects core dimensions of farm family life but also the agricultural sector more widely. Intergenerational farm transfer in particular is increasingly viewed as fundamental to the sustainability and development of global agriculture. In the majority of EU countries, the average age of farmers is increasing, while the number of farmers under 40 years of age is decreasing. There is growing concern that this demographic trend may have negative impacts on the agricultural industry because it is younger and not older farmers who are associated with more efficient and effective production practices. The question of what motivates decisions to transfer farms is a complex one, and research to date has not apparently enlightened agricultural policy to the extent that current trends towards an ageing farm population are being managed. This research aims to investigate economic and financial aspects of the policy drivers of farm succession and inheritance in Ireland to understand what it is about the policy environment that is failing to stimulate higher levels of farm transfer. It draws on the Teagasc National Farm Survey data which provides Irish data to the Farm Accountancy Data Network in the European Commission. A hypothetical microsimulation model is used to investigate economic factors of farm transfers, with scenarios created to test these factors and their impacts on the transfer process. The Net Present Value (NPV) of income streams for farmers and their successors are calculated to assess which scenarios have the highest/lowest financial effects. The findings illustrate a range of possible scenarios for farm succession/inheritance, with some results indicating that under current policy retaining a farm until death may be more economically beneficial to a farmer than transferring land before death

Risky (farm) business: Perceptions of economic risk in farm succession and inheritance

peer-reviewedHighlights • Generational renewal is high on the political agenda for agriculture, with young farmers linked to positive outcomes. • There are limited policy incentives for older farmers to consider engaging in the farm succession and inheritance process. • Farmers perceive risks and uncertainties regarding the transfer process, and thus avoid handing over to their successors. • Taxation, retirement income, long term care cost, and marital breakdown are motivations for farmers to retain ownership. • Financial incentives related to generational renewal must aim to alleviate the level of risk perceived by farmers.Royal Dublin Societ

A pragmatic multi-centre randomised controlled trial of fluid loading in high-risk surgical patients undergoing major elective surgery - the FOCCUS study

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