Learning from natural sediments to tackle microplastics challenges: A multidisciplinary perspective

Although the study of microplastics in the aquatic environment incorporates a diversity of research fields, it is still in its infancy in many aspects while comparable topics have been studied in other disciplines for decades. In particular, extensive research in sedimentology can provide valuable insights to guide future microplastics research. To advance our understanding of the comparability of natural sediments with microplastics, we take an interdisciplinary look at the existing literature describing particle properties, transport processes, sampling techniques and ecotoxicology. Based on our analysis, we define seven research goals that are essential to improve our understanding of microplastics and can be tackled by learning from natural sediment research, and identify relevant tasks to achieve each goal. These goals address (1) the description of microplastic particles, (2) the interaction of microplastics with environmental substances, (3) the vertical distribution of microplastics, (4) the erosion and deposition behaviour of microplastics, (5) the impact of biota on microplastic transport, (6) the sampling methods and (7) the microplastic toxicity. When describing microplastic particles, we should specifically draw from the knowledge of natural sediments, for example by using shape factors or applying methods for determining the principal dimensions of non-spherical particles. Sediment transport offers many fundamentals that are transferable to microplastic transport, and could be usefully applied. However, major knowledge gaps still exist in understanding the role of transport modes, the influence of biota on microplastic transport, and the importance and implementation of the dynamic behaviour of microplastics as a result of time-dependent changes in particle properties in numerical models. We give an overview of available sampling methods from sedimentology and discuss their suitability for microplastic sampling, which can be used for creating standardised guidelines for future application with microplastics. In order to comprehensively assess the ecotoxicology of microplastics, a distinction must be made between the effects of the polymers themselves, their physical form, the plastic-associated chemicals and the attached pollutants. This review highlights areas where we can rely on understanding and techniques from sediment research - and areas where we need new, microplastic-specific knowledge - and synthesize recommendations to guide future, interdisciplinary microplastic research

Novel characterisation methods for pore systems of seal rocks in reservoirs used for downhole gas production and storage

Seal rocks, also called cap rocks, are a crucial and sometimes overlooked factor (due to not being the primary factor in exploration, having more of a role in the resource evaluation and development) in the evaluation of a potential gas accumulation, and is critical in downhole gasification (enhanced gas recovery) and storage of other gases. Shale rocks are the most common seal rock in conventional reservoirs; currently shales are providing an unconventional oil and gas source which can act as a potential buffer to the energy industry as it transitions towards renewable energies (which are still in their formative years) whilst there is a continued rise in demand for energy globally. Over the past ten years there has been a boom in shale gas production in the United States (Barsotti et al., 2016; Li et al., 2016; Yu et al., 2016), and it is anticipated that this boom may be repeated in the UK (Andrews, 2013). Downhole gasification (enhanced gas recovery) offers a potential way to produce from these “difficult-to-extract” (as a result of low permeability’s) reservoirs by using carbon dioxide as a displacement gas for methane. At the same time this carbon dioxide can be also be stored resulting in the environment being exposed to less greenhouse gas (Kim, Cho and Lee, 2017; D. Liu et al., 2019). However, it is erroneous to consider shales as a completely impermeable layer, and their ability to retain different fluids is variable (controlled by the capillary entry pressure and/or the permeability and the extent of diffusive loses) which could result in some/all of them being ineffective at retaining carbon dioxide. This is because shales are highly complex and anisotropic containing pores over several orders of magnitude. Typically they have a significantly low permeability and porosity, combined with structural and chemical heterogeneities of shales mean that physical processes are significantly impacted. Importantly the structure-transport relationship is complex resulting in processes such as hydrocarbon migration, methane extraction, gas storage, or carbon sequestration being poorly understand. This project proposes the development of several novel characterisation techniques and combinations of complementary techniques to characterise the multi-scale properties of shales in order to more accurately provide the information needed for secure decisions regarding gas production and storage. In this work mercury porosimetry, together with mercury thermoporometry, and computerised x-ray tomography (CXT) were performed on post-porosimetry samples containing entrapped mercury, to characterise the pore structure of cap-rocks. However limitations were identified where mercury was trapped in pores too large to sufficiently suppress the bulk melting point (thermoporometry) such that a separate melting peak formed. However, the combined use of mercury porosimetry and computerised x-ray tomography was effective at highlighting the location of trapped mercury, but was ineffective at providing quantitative results regarding the macroporosity of the sample. Further drawbacks of mercury porosimetry based analysis are the potential destruction of experimental material where further analysis cannot be carried out unless mercury forms part of the experimental technique (i.e. thermoporometry and computerised x-ray tomography as described above). Therefore, gas overcondensation, was proposed as an alternative technique as a bridge between micro-pore characterisation, below the limit of mercury detection, up to macro- pores which are undetected in conventional sorption experiments, with the additional benefit that the overcondensation method preserves experimental material. In previous work, gas sorption experiments typically consist of a boundary adsorption isotherm up to a restricted maximum pressure (e.g. up to 0.995 p/p0). Following this there is a pseudo-boundary desorption isotherm, which is merely a descending curve since complete pore- filling with liquid-like condensate was not achieved. As a result of this conventional gas sorption alone cannot prove the complete pore size range up to large macro-pores. Gas overcondensation experiments can be expanded with gas sorption scanning curves which have successfully revealed advanced condensation effects, allowing probing of the inter- relationship and spatial juxtaposition of multi-scale porosities. Gas overcondensation and scanning loops were successfully used for the Utica and Bowland samples to reveal where additional percolations knee develop that are characteristic of a particular pore size within the wider pore network (Utica). Work on the Bowland was able to determine that there are some large macro-pores shielded by pore necks of <4nm; complimentary adsorption calorimetry work was able to relate this shielding to pore necks by calculating the mass transfer and thermokinetic properties of the samples. Prior to the use of gas overcondensation mineralogy was assessed with the use of conventional gas sorption where results (Marcellus and Utica) showed an inverse relationship between carbonate and illite quantities (i.e. an increasing carbonate content was associated to a decreasing illite content). Utica surface areas demonstrated a strong correlation to illite quantity, whereas Marcellus surface areas demonstrated a weaker correlation to illite. For both samples there was good correlation to the total organic carbon. With the new information gained from gas overcondesation it has allowed for additional, and more advanced correlations to be made with other physical properties of shales such as the mineralogy. It was found that for the changeover period (Utica samples), from primarily clay to carbonaceous deposits, there was an associated growth in the disorder of the pore network over particular key length-scales. These length-scales were highlighted by percolation processes in the gas overcondensation and scanning curves. This peaking in disorder was also associated to a peak in total organic carbon content and the accessible porosity was shown to be dominated by the organic carbon phase. Following the identification of this trend with the use of gas overceondensation and mineralogy, numerical analysis techniques were used to replicate these findings with the use of the homotattic patch model. It was established that with the use of conventional gas sorption (nitrogen) isotherms and isotherms for the pure mineral phases of the sample good results can be generated indicating the associated quantity of each mineral to the sample

Textbook of Patient Safety and Clinical Risk Management

Implementing safety practices in healthcare saves lives and improves the quality of care: it is therefore vital to apply good clinical practices, such as the WHO surgical checklist, to adopt the most appropriate measures for the prevention of assistance-related risks, and to identify the potential ones using tools such as reporting & learning systems. The culture of safety in the care environment and of human factors influencing it should be developed from the beginning of medical studies and in the first years of professional practice, in order to have the maximum impact on clinicians' and nurses' behavior. Medical errors tend to vary with the level of proficiency and experience, and this must be taken into account in adverse events prevention. Human factors assume a decisive importance in resilient organizations, and an understanding of risk control and containment is fundamental for all medical and surgical specialties. This open access book offers recommendations and examples of how to improve patient safety by changing practices, introducing organizational and technological innovations, and creating effective, patient-centered, timely, efficient, and equitable care systems, in order to spread the quality and patient safety culture among the new generation of healthcare professionals, and is intended for residents and young professionals in different clinical specialties

Novel characterisation methods for pore systems of seal rocks in reservoirs used for downhole gas production and storage

Seal rocks, also called cap rocks, are a crucial and sometimes overlooked factor (due to not being the primary factor in exploration, having more of a role in the resource evaluation and development) in the evaluation of a potential gas accumulation, and is critical in downhole gasification (enhanced gas recovery) and storage of other gases. Shale rocks are the most common seal rock in conventional reservoirs; currently shales are providing an unconventional oil and gas source which can act as a potential buffer to the energy industry as it transitions towards renewable energies (which are still in their formative years) whilst there is a continued rise in demand for energy globally. Over the past ten years there has been a boom in shale gas production in the United States (Barsotti et al., 2016; Li et al., 2016; Yu et al., 2016), and it is anticipated that this boom may be repeated in the UK (Andrews, 2013). Downhole gasification (enhanced gas recovery) offers a potential way to produce from these “difficult-to-extract” (as a result of low permeability’s) reservoirs by using carbon dioxide as a displacement gas for methane. At the same time this carbon dioxide can be also be stored resulting in the environment being exposed to less greenhouse gas (Kim, Cho and Lee, 2017; D. Liu et al., 2019). However, it is erroneous to consider shales as a completely impermeable layer, and their ability to retain different fluids is variable (controlled by the capillary entry pressure and/or the permeability and the extent of diffusive loses) which could result in some/all of them being ineffective at retaining carbon dioxide. This is because shales are highly complex and anisotropic containing pores over several orders of magnitude. Typically they have a significantly low permeability and porosity, combined with structural and chemical heterogeneities of shales mean that physical processes are significantly impacted. Importantly the structure-transport relationship is complex resulting in processes such as hydrocarbon migration, methane extraction, gas storage, or carbon sequestration being poorly understand. This project proposes the development of several novel characterisation techniques and combinations of complementary techniques to characterise the multi-scale properties of shales in order to more accurately provide the information needed for secure decisions regarding gas production and storage. In this work mercury porosimetry, together with mercury thermoporometry, and computerised x-ray tomography (CXT) were performed on post-porosimetry samples containing entrapped mercury, to characterise the pore structure of cap-rocks. However limitations were identified where mercury was trapped in pores too large to sufficiently suppress the bulk melting point (thermoporometry) such that a separate melting peak formed. However, the combined use of mercury porosimetry and computerised x-ray tomography was effective at highlighting the location of trapped mercury, but was ineffective at providing quantitative results regarding the macroporosity of the sample. Further drawbacks of mercury porosimetry based analysis are the potential destruction of experimental material where further analysis cannot be carried out unless mercury forms part of the experimental technique (i.e. thermoporometry and computerised x-ray tomography as described above). Therefore, gas overcondensation, was proposed as an alternative technique as a bridge between micro-pore characterisation, below the limit of mercury detection, up to macro- pores which are undetected in conventional sorption experiments, with the additional benefit that the overcondensation method preserves experimental material. In previous work, gas sorption experiments typically consist of a boundary adsorption isotherm up to a restricted maximum pressure (e.g. up to 0.995 p/p0). Following this there is a pseudo-boundary desorption isotherm, which is merely a descending curve since complete pore- filling with liquid-like condensate was not achieved. As a result of this conventional gas sorption alone cannot prove the complete pore size range up to large macro-pores. Gas overcondensation experiments can be expanded with gas sorption scanning curves which have successfully revealed advanced condensation effects, allowing probing of the inter- relationship and spatial juxtaposition of multi-scale porosities. Gas overcondensation and scanning loops were successfully used for the Utica and Bowland samples to reveal where additional percolations knee develop that are characteristic of a particular pore size within the wider pore network (Utica). Work on the Bowland was able to determine that there are some large macro-pores shielded by pore necks of <4nm; complimentary adsorption calorimetry work was able to relate this shielding to pore necks by calculating the mass transfer and thermokinetic properties of the samples. Prior to the use of gas overcondensation mineralogy was assessed with the use of conventional gas sorption where results (Marcellus and Utica) showed an inverse relationship between carbonate and illite quantities (i.e. an increasing carbonate content was associated to a decreasing illite content). Utica surface areas demonstrated a strong correlation to illite quantity, whereas Marcellus surface areas demonstrated a weaker correlation to illite. For both samples there was good correlation to the total organic carbon. With the new information gained from gas overcondesation it has allowed for additional, and more advanced correlations to be made with other physical properties of shales such as the mineralogy. It was found that for the changeover period (Utica samples), from primarily clay to carbonaceous deposits, there was an associated growth in the disorder of the pore network over particular key length-scales. These length-scales were highlighted by percolation processes in the gas overcondensation and scanning curves. This peaking in disorder was also associated to a peak in total organic carbon content and the accessible porosity was shown to be dominated by the organic carbon phase. Following the identification of this trend with the use of gas overceondensation and mineralogy, numerical analysis techniques were used to replicate these findings with the use of the homotattic patch model. It was established that with the use of conventional gas sorption (nitrogen) isotherms and isotherms for the pure mineral phases of the sample good results can be generated indicating the associated quantity of each mineral to the sample

1995 BRAC Commission

Base Visit (Fort Buchanan, New London, Anniston Army Depot, Naval Air Station Corpus Christi). (Box 87