Phase and partitioning behavior of phenols and polycyclic aromatic hydrocarbons in offshore oil and gas produced water

Produced water constitutes the largest volume of waste from offshore oil and gas operations and is composed of a wide range of organic and inorganic compounds. Although treatment processes have to meet strict oil in water regulations, the definition of “oil” is a function of the analysis process and may include aliphatic hydrocarbons which have limited environmental impact due to degradability whilst ignoring problematic dissolved petroleum species. This thesis presents the partitioning behavior of oil in produced water as a function of temperature and salinity to identify compounds of environmental concern. Phenol, p-cresol, and 4-tert-butylphenol were studied because of their xenoestrogenic power; other compounds studied are polycyclic aromatic hydrocarbon PAHs which include naphthalene, fluorene, phenanthrene, and pyrene. Partitioning experiments were carried out in an Innova incubator for 48 hours, temperature was varied from 4ﾟC to 70ﾟC, and two salinity levels of 46.8‰ and 66.8‰ were studied. Results obtained showed that the dispersed oil concentration in the water reduces with settling time and equilibrium was attained at 48 h settling time. Polycyclic aromatic hydrocarbons (PAHs) partitions based on dispersed oil concentration whereas phenols are not significantly affected by dispersed oil concentration. Higher temperature favors partitioning of PAHs into the water phase. Salinity has negligible effect on partitioning pattern of phenols and PAHs studied. Simulation results obtained from the Aspen HYSYS model shows that temperature and oil droplet distribution greatly influences the efficiency of produced water treatment system.

(Table S1) Uranium and Thorium isotopes and U/Th ages of IODP Exp310 cores from offshore Tahiti

The timing of sea-level change provides important constraints on the mechanisms driving Earth's climate between glacial and interglacial states. Fossil corals constrain the timing of past sea level by their suitability for dating and their growth position close to sea level. The coral-derived age for the last deglaciation is consistent with climate change forced by Northern Hemisphere summer insolation (NHI), but the timing of the penultimate deglaciation is more controversial. We found, by means of uranium/thorium dating of fossil corals, that sea level during the penultimate deglaciation had risen to ~85 meters below the present sea level by 137,000 years ago, and that it fluctuated on a millennial time scale during deglaciation. This indicates that the penultimate deglaciation occurred earlier with respect to NHI than the last deglacial, beginning when NHI was at a minimum.

dD values of C31 n-alkane (dD wax) from sediment core GeoB9501-4 offshore the Northwest African Sahel

Various studies have demonstrated that the stable hydrogen isotopic composition (dD) of terrestrial leaf waxes tracks that of precipitation (dDprecip) both spatially across climate gradients and over a range of different timescales. Yet, reconstructed estimates of dDprecip and corresponding rainfall typically remain largely qualitative, due mainly to uncertainties in plant ecosystem net fractionation, relative humidity, and the stability of the amount effect through time. Here we present dD values of the C31n-alkane (dDwax) from a marine sediment core offshore the Northwest (NW) African Sahel covering the past 100 years and overlapping with the instrumental record of rainfall. We use this record to investigate whether accurate, quantitative estimates of past rainfall can be derived from our dDwax time series. We infer the composition of vegetation (C3/C4) within the continental catchment area by analysis of the stable carbon isotopic composition of the same compounds (d13Cwax), calculated a net ecosystem fractionation factor, and corrected the dDwax time series accordingly to derive dDprecip. Using the present-day relationship between dDprecip and the amount of precipitation in the tropics, we derive quantitative estimates of past precipitation amounts. Our data show that (a) vegetation composition can be inferred from d13Cwax, (b) the calculated net ecosystem fractionation represents a reasonable estimate, and (c) estimated total amounts of rainfall based on dDwax correspond to instrumental records of rainfall. Our study has important implications for future studies aiming to reconstruct rainfall based on dDwax; the combined data presented here demonstrate that it is feasible to infer absolute rainfall amounts from sedimentary dDwax in tandem with d13Cwax in specific depositional settings.

Thick-walled composite tubes for offshore applications : an example of stress and failure analysis for filament-wound multi-layered pipes

Peer reviewed

Frontier exploration and the North Atlantic Igneous Province : new insights from a 2.6 km offshore volcanic sequence in the NE Faroe–Shetland Basin

Peer reviewed

Thick-walled composite tubes for offshore applications : an example of stress and failure analysis for filament-wound multi-layered pipes

Peer reviewed

Frontier exploration and the North Atlantic Igneous Province : new insights from a 2.6 km offshore volcanic sequence in the NE Faroe–Shetland Basin

Peer reviewed

Subsea DC Collection Grid with High Power Security for Offshore Renewables

This work was supported by the Engineering and Physical Sciences Research Council [grant number EP/K006428/1]; and the European Regional Development Fund [grant number LUPS/ERDF/2010/4/1/0164].

DC fault performance and cost analysis of DC grids for connecting multiple offshore wind farms

ACKNOWLEDGMENT We are thankful to RTE for financial support of this project.

Thick-walled composite tubes for offshore applications : an example of stress and failure analysis for filament-wound multi-layered pipes

Peer reviewed

Promoção do desenvolvimento cognitivo em idosos com a doença de Alzheimer – as práticas e os contextos de estruturas residenciais para idosos

O crescimento da fatia da população com idade superior a 65 anos tem levado a uma maior atenção sobre as consequências sociais, económicas, políticas, principalmente nos países desenvolvidos. O estudo que se apresenta é uma abordagem predominantemente qualitativa e tem características descritivas. Pretendemos conhecer de que forma as estruturas residenciais para idosos promovem o desenvolvimento cognitivo em idosos com a doença de Alzheimer através de atividades de estimulação cognitiva. Foram realizadas entrevistas em profundidade aos técnicos responsáveis por quatro estruturas residenciais de idosos (ERPI), da zona centro de Portugal e os dados recolhidos foram triangulados com a análise documental e a observação naturalista realizada pela investigadora, dado que desenvolve a sua atividade profissional neste contexto Os resultados revelam que as estruturas residenciais para idosos estão sensíveis à importância de criar momentos de estimulação cognitivas para idosos com a doença de Alzheimer. Esta tarefa está dificultada não só pela lacuna na formação específica dos técnicos, como também pelo aumento de utentes com estas e outras necessidades, condicionando a ação individualizada destes técnicos. As estruturas residenciais para idosos, consideram que é necessário fazer uma adaptação do processo de institucionalização quando se trata de um utente com esta demência. Existe também uma grande preocupação em manter a capacidade motora, estimulação cognitiva, mantendo assim por mais tempo as capacidades de cada idoso por forma a ter uma melhor qualidade de vida e autonomia.

Intervenção das estruturas residenciais no diagnóstico e acompanhamento de doentes de alzheimer

O envelhecimento traz consigo alguns défices cognitivos que podem levar á demência. Um dos tipos de demência mais comum é a doença de Alzheimer e, atualmente, as Estruturas Residenciais (ER) são um tipo de resposta social para acolher este tipo de utentes. O objetivo da investigação foi compreender a intervenção das Estruturas Residenciais no diagnóstico e acompanhamento de doentes de Alzheimer. Para tal, através de uma metodologia qualitativa, foram selecionadas por conveniência quatro Estruturas Residenciais do distrito de Leiria e realizou-se uma entrevista com guião semi-estruturado e um inquérito por questionário às suas diretoras técnicas. Conclui-se que, apesar das adaptações realizadas ao longo dos anos, o ambiente físico das instituições em estudo não está adaptado a utentes com este tipo de patologia. No que concerne aos recursos humanos, existe a necessidade de mais técnicos especializados e, apesar do rácio das Auxiliares de Ação Direta (AAD) estar de acordo com o exigido pela Segurança Social, existe falta de formação das mesmas. Notou-se que são realizadas fichas de avaliação diagnóstica inicial no entanto, ainda há evidentes dificuldades no cumprimento dos Planos Individuais (PI). As atividades de estimulação/ocupação não são planeadas em específicos para utentes com a doença de Alzheimer e apesar da falta de formação/informação das famílias em relação à patologia evidencia-se que estão cada vez mais presentes. Perspetiva-se para o futuro a existência de instituições mais adaptadas para acolher este tipo de utentes.

Compilation of organic carbon distribution and sedimentology in the surface sediments on the continental margin offshore southwestern Africa

In this study we demonstrate the relevance of lateral particle transport in nepheloid layers for organic carbon (OC) accumulation and burial across high-productive continental margins. We present geochemical data from surface sediments and suspended particles in the bottom nepheloid layer (BNL) from the most productive coastal upwelling area of the modern ocean, the Benguela upwelling system offshore southwest Africa. Interpretation of depositional patterns and comparison of downslope trends in OC content, organic matter composition, and 14C age between suspended particles and surface sediments indicate that lateral particle transport is the primary mechanism controlling supply and burial of OC. We propose that effective seaward particle transport primarily along the BNL is a key process that promotes and maintains local high sedimentation rates, ultimately causing high preservation of OC in a depocenter on the upper slope offshore Namibia. As lateral transport efficiently displaces areas of enhanced OC burial from maximum production at highly productive continental margins, vertical particle flux models do not sufficiently explain the relationship between primary production and shallow-marine OC burial. On geologic time scales, the widest distribution and strongest intensity of lateral particle transport is expected during periods of rapid sea-level change. At times in the geologic past, widespread downslope lateral transport of OC thus may have been a primary driver of enhanced OC burial at deeper continental slopes and abyssal basins.

Directional wave measurements using the Offshore Sensing Sailbuoy, link to MATLAB file

An autonomous vessel, the Offshore Sensing Sailbuoy, was used for wave measurements near the Ekofisk oil platform complex in the North Sea (56.5 N, 3.2 E, operated by ConocoPhilllips) from 6 to 20 November 2015. Being 100% wind propelled, the Sailbuoy has two-way communication via the Iridium network and has the capability for missions of six months or more. It has previously been deployed in the Arctic, Norwegian Sea and the Gulf of Mexico, but this was the first real test for wave measurements. During the campaign it held position about 20km northeast of Ekofisk (on the lee side) during rough conditions. Mean wind speed measured at Ekofisk during the campaign was near 9.8m/s, with a maximum of 20.4m/s, with wind mostly from south and south west. A Datawell MOSE G1000 GPS based 2Hz wave sensor was mounted on the Sailbuoy. Mean significant wave height (Hs 1hr) measured was 3m, whereas maximum Hs was 6m. Mean wave period was 7.7s, while maximum wave height, Hmax, was 12.6m. These measurements have been compared with non-directional Waverider observations at the Ekofisk complex. Mean Hs at Ekofisk was 3.1m, while maximum Hs was 6.5m. Nevertheless, the correlation between the two measurements was high (97%). Spectra comparison was also good, except for low Hs (~1m), where the motion of the vessel seemed to influence the measurements. Nevertheless, the Sailbuoy performed well during this campaign, and results suggests that it is a suitable platform for wave measurements in rather rough sea conditions.

Unstructured grid modelling of offshore wind farm impacts on seasonally stratified shelf seas

Shelf seas comprise approximately 7% of the world’s oceans and host enormous economic activity. Development of energy installations (e.g. Offshore Wind Farms (OWFs), tidal turbines) in response to increased demand for renewable energy requires a careful analysis of potential impacts. Recent remote sensing observations have identified kilometrescale impacts from OWFs. Existing modelling evaluating monopile impacts has fallen into two camps: small-scale models with individually resolved turbines looking at local effects; and large-scale analyses but with sub-grid scale turbine parameterisations. This work straddles both scales through a 3D unstructured grid model (FVCOM): wind turbine monopiles in the eastern Irish Sea are explicitly described in the grid whilst the overall grid domain covers the south-western UK shelf. Localised regions of decreased velocity extend up to 250 times the monopile diameter away from the monopile. Shelf-wide, the amplitude of the M2 tidal constituent increases by up to 7%. The turbines enhance localised vertical mixing which decreases seasonal stratification. The spatial extent of this extends well beyond the turbines into the surrounding seas. With significant expansion of OWFs on continental shelves, this work highlights the importance of how OWFs may impact coastal (e.g. increased flooding risk) and offshore (e.g. stratification and nutrient cycling) areas.