HPC and CFD in the marine industry: past, present and future

This paper explores the use of Computational Fluid Dynamics (CFD) applications on High Performance Computing (HPC) platforms from the perspective of a user engaged in Naval Architecture research. The paper will consider the significant limitations which were imposed on research boundaries prior to present HPC capabilities, how this impacted development in the field and the implications for industry. One particular example is the costly experimental testing which, due to resource constraints, is generally restricted to model scale. It will then present an overview of the numerical simulation capabilities using current HPC performance and capability. With the increase of computational power and capacity, CFD simulations are proving to be more accurate and reliable. Being relatively cheaper and more time efficient, numerical methods are becoming the preferred choice within the industry compared to traditional experimental tests. Nevertheless, certain experimental procedures cannot be numerically replicated with the current levels of computational capacity. The future needs and challenges of research and development will be outlined and discussed, highlighting the significant impact exascale computing will have in the field

Imaging of adult ocular and orbital pathology - a pictorial review

Orbital pathology often presents a diagnostic challenge to the reporting radiologist. The aetiology is protean, and clinical input is therefore often necessary to narrow the differential diagnosis. With this manuscript, we provide a pictorial review of adult ocular and orbital pathology.peer-reviewe

Design optimisation of Propeller Boss Cap Fins for enhanced propeller performance

Economic pressures and regulatory requirements have brought about a great interest in improving ship propulsion efficiency. This can be exercised by installing Energy Saving Devices (ESD) such as Propeller Boss Cap Fins (PBCF). This paper demonstrates an approach for optimising PBCF by using Computational Fluid Dynamics (CFD) analysis. The conducted Reynolds-averaged Navier-Stokes (RANS) CFD open water model tests were validated by comparison with experimental data until the simulation was deemed satisfactory within the capabilities and limitations of the model. A design and optimisation procedure was defined to analyse the impact of ESDs on propeller efficiency and then used to evaluate the influence of alternative geometric parameters and locations of the PBCF on the hub. This analysis was done at full scale using high fidelity CFD-based RANS methods. Outcomes of the study include a design and optimisation process that can be used for the analysis of other ESDs on the market. The influences of various PBCF geometry were examined with optimal solutions presented for the analysis case. Results indicated a net energy efficiency improvement of 1.3% contributing to a substantial minimisation of cost and energy consumption. A reduction in the hub vortex was also clearly identified and presented

A generic wake analysis tool and its application to the Japan Bulk Carrier test case

Economic pressures and regulatory obligations have brought about a great interest in improving ship propulsion efficiency. This has motivated and directed research to improve the hydrodynamic performance of a vessel thus seeking the development and generation of optimised designs. When analysing flow characteristics of a vessel, particular attention is given to analysing its wake field and stern flow characteristics. For the detailed analysis of the wake flow field, a Wake Analysis Tool (WAT) was developed within the programming environment of a commercial CAE tool. The WAT is based on a framework that enables easy interaction to an external CFD solver reading flow field properties from a generic csv file. The wake flow field is visualised and analysed in schematic form according to the standard and customized (i.e. the British Ship Research Association criteria) wake analyses. By coupling the CAE tool with a commercial flow solver, an example was given how to use the wake tool in a fully automated simulation process. Finally, the wake tool was used to analyse the nominal propeller wake flow of the Japan Bulk Carrier (JBC) thus showing how it can be efficiently applied to a set of numerical results

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

The development of intelligent hull forms of large ships for energy efficient transportation

It is not usual that the interests of ship owners are aligned with maritime legislation requirements with the incentives to make ships more efficient. Owners seek to reduce the ship operating costs whilst entities, such as the IMO, push for a more environment friendly marine industry.;A ship's efficiency can be improved by optimising the hull form and/or by installing Energy Saving Devices (ESD) in order to improve the hydrodynamic performance and fluid flow of a vessel. These two areas are not new to the industry and have been investigated using various methods, including computational fluid dynamics (CFD) procedures. The use of CFD for ship performance analyses is becoming more popular in the maritime industry due to its cost-effective capabilities. The continuous development of numerical simulation (CFD) as well as high performance computing opens doors to new areas of investigation and allows research to further study topics that have been previously looked into as well as research questions that have never been explored.;The general aim of this PhD thesis is to contribute to the body of knowledge by shedding light on improving the hydrodynamic performance of large ships for energy efficient transportation. This was achieved by accomplishing a series of objectives and case studies that addressed various research questions.;This study initially proposes an intelligent state-of-the-art methodology for predicting and enhancing the hull-propeller interaction of a vessel using numerical techniques (CFD), optimisation procedures and high-performance computing to identify optimal stern designs as well as understanding the physics and impact of Energy Saving Device/s that could help improve the stern flow characteristics.;The CFD method, that was used to predict the performance for all the various case studies, was validated and verified using well established procedures. The implementation of the recently available curvature correction feature in the numerical model and its enhanced wake prediction capabilities were clearly demonstrated.;Moreover, various types of post-processing CFD analyses that were deemed useful to understand the hydrodynamic performance of a vessel were listed and outlined.;A practical full-scale stern form optimisation procedure for a bulk carrier was developed and demonstrated. Furthermore, whether the quality of a nominal wake can provide any insight into the propeller performance of a vessel was investigated and evaluated.;With regards to the case studies investigating Energy Saving Devices, Propeller Boss Cap Fins were analysed in open water full-scale conditions to understand the physics, function and working principles of such technologies. A state-of-the-art full-scale PBCF optimisation procedure was also demonstrated. The performance of a Wake Equalising Duct at different scale conditions was investigated and compared. The study indicated that the duct is not as effective in full-scale. The reasons and findings were thoroughly discussed and outlined.;The thesis also focused on the research questions regarding the installation of multiple Energy Saving Devices on a ship system. Whether the benefits are directly cumulative or whether the ESDs affect the flow regimes of one another? Thus, a case study was carried out by investigating seven combinations using PBCF, a duct and stator fins. The performance of each condition was clearly outlined, discussed and explained.;This author believes that this study has exhibited and proven the ability and applicability of computational fluid dynamics (CFD) to better understand the hydrodynamics of a ship system and improve hull-propeller interaction dynamics. The studies and research in this thesis contribute to the industry as well as academia by shedding more light on large ship hydrodynamic systems.It is not usual that the interests of ship owners are aligned with maritime legislation requirements with the incentives to make ships more efficient. Owners seek to reduce the ship operating costs whilst entities, such as the IMO, push for a more environment friendly marine industry.;A ship's efficiency can be improved by optimising the hull form and/or by installing Energy Saving Devices (ESD) in order to improve the hydrodynamic performance and fluid flow of a vessel. These two areas are not new to the industry and have been investigated using various methods, including computational fluid dynamics (CFD) procedures. The use of CFD for ship performance analyses is becoming more popular in the maritime industry due to its cost-effective capabilities. The continuous development of numerical simulation (CFD) as well as high performance computing opens doors to new areas of investigation and allows research to further study topics that have been previously looked into as well as research questions that have never been explored.;The general aim of this PhD thesis is to contribute to the body of knowledge by shedding light on improving the hydrodynamic performance of large ships for energy efficient transportation. This was achieved by accomplishing a series of objectives and case studies that addressed various research questions.;This study initially proposes an intelligent state-of-the-art methodology for predicting and enhancing the hull-propeller interaction of a vessel using numerical techniques (CFD), optimisation procedures and high-performance computing to identify optimal stern designs as well as understanding the physics and impact of Energy Saving Device/s that could help improve the stern flow characteristics.;The CFD method, that was used to predict the performance for all the various case studies, was validated and verified using well established procedures. The implementation of the recently available curvature correction feature in the numerical model and its enhanced wake prediction capabilities were clearly demonstrated.;Moreover, various types of post-processing CFD analyses that were deemed useful to understand the hydrodynamic performance of a vessel were listed and outlined.;A practical full-scale stern form optimisation procedure for a bulk carrier was developed and demonstrated. Furthermore, whether the quality of a nominal wake can provide any insight into the propeller performance of a vessel was investigated and evaluated.;With regards to the case studies investigating Energy Saving Devices, Propeller Boss Cap Fins were analysed in open water full-scale conditions to understand the physics, function and working principles of such technologies. A state-of-the-art full-scale PBCF optimisation procedure was also demonstrated. The performance of a Wake Equalising Duct at different scale conditions was investigated and compared. The study indicated that the duct is not as effective in full-scale. The reasons and findings were thoroughly discussed and outlined.;The thesis also focused on the research questions regarding the installation of multiple Energy Saving Devices on a ship system. Whether the benefits are directly cumulative or whether the ESDs affect the flow regimes of one another? Thus, a case study was carried out by investigating seven combinations using PBCF, a duct and stator fins. The performance of each condition was clearly outlined, discussed and explained.;This author believes that this study has exhibited and proven the ability and applicability of computational fluid dynamics (CFD) to better understand the hydrodynamics of a ship system and improve hull-propeller interaction dynamics. The studies and research in this thesis contribute to the industry as well as academia by shedding more light on large ship hydrodynamic systems

PBCF design optimisation and propulsion efficiency impact

Economic pressures and regulatory requirements have brought about a great interest in improving ship propulsion efficiency. This can be exercised by installing Energy Saving Devices (ESD) such as Propeller Boss Cap Fins (PBCF) . This paper demonstrates an approach for optimising PBCF by using Computational Fluid Dynamics (CFD) analysis. The conducted CFD open water model tests were validated by comparison with experimental data until the simulation was deemed satisfactory within the capabilities and limitations of the model. A design and optimisation procedure was defined to analyse the impact of ESDs on propeller efficiency and then used to evaluate the different geometric parameters and locations of the PBCF on the hub. This analysis was done at full scale using high fidelity CFD - based RANS methods. Outcomes of the study include a design and optimisation process that can be used for the analysis of other ESDs on the market. The influences of varying the geometry of the PBCF were examined with optimal solutions presented for the analysis case. The impact on the regulated Energy Efficiency Design Index (EEDI) and ESD savings were then discussed along with the influences on the energy efficiency

Drama, Performance Ethnography, and Self-Esteem

Self-esteem affects learning, performance, self-worth, and quality of life, particularly in persons with dyslexia, or rather how students with dyslexia are mis/understood and supported. Dyslexia does not only affect literacy but also affects emotional well-being. Webb concludes that for children to feel successful, they need to become aware of their unique learning strengths to apply them effectively to strengthen weaknesses. Drama and Performance Ethnography (PE) can be support strategies. Workshops were carried out with a group of adolescent youngsters with dyslexia. The aim was to provide a safe environment where they could find their voice and gain self-confidence through drama and PE to provide opportunities to address self-esteem and to provide insights for policies and practice. This article intends to listen to these youngsters’, also co-authors, and their parents’ narratives of this experience

Surgical site infection after gastrointestinal surgery in children : an international, multicentre, prospective cohort study

Introduction Surgical site infection (SSI) is one of the most common healthcare-associated infections (HAIs). However, there is a lack of data available about SSI in children worldwide, especially from low-income and middle-income countries. This study aimed to estimate the incidence of SSI in children and associations between SSI and morbidity across human development settings. Methods A multicentre, international, prospective, validated cohort study of children aged under 16 years undergoing clean-contaminated, contaminated or dirty gastrointestinal surgery. Any hospital in the world providing paediatric surgery was eligible to contribute data between January and July 2016. The primary outcome was the incidence of SSI by 30 days. Relationships between explanatory variables and SSI were examined using multilevel logistic regression. Countries were stratified into high development, middle development and low development groups using the United Nations Human Development Index (HDI). Results Of 1159 children across 181 hospitals in 51 countries, 523 (45 center dot 1%) children were from high HDI, 397 (34 center dot 2%) from middle HDI and 239 (20 center dot 6%) from low HDI countries. The 30-day SSI rate was 6.3% (33/523) in high HDI, 12 center dot 8% (51/397) in middle HDI and 24 center dot 7% (59/239) in low HDI countries. SSI was associated with higher incidence of 30-day mortality, intervention, organ-space infection and other HAIs, with the highest rates seen in low HDI countries. Median length of stay in patients who had an SSI was longer (7.0 days), compared with 3.0 days in patients who did not have an SSI. Use of laparoscopy was associated with significantly lower SSI rates, even after accounting for HDI. Conclusion The odds of SSI in children is nearly four times greater in low HDI compared with high HDI countries. Policies to reduce SSI should be prioritised as part of the wider global agenda.Peer reviewe