Turbulent premixed flames in a model gas turbine combustor: fuel sensitivity and flame dynamics

The demand for energy security and reduction of greenhouse gas emissions has led to a surge of interest in the development of high-efficiency and low-emission gas turbine engines that can run on alternative low carbon content fuels, such as hydrogen-enriched fuel and syngas. However, the combustion characteristics of these fuels can significantly alter the flame characteristics and operability range of existing combustors. Therefore, it is crucial to gain a better understanding of the turbulent combustion characteristics of these fuels from both fundamental and practical perspectives. In this thesis, a combination of numerical and experimental diagnostic methodologies has been employed to investigate how the fuel characteristics can affect the fundamental properties of flames and their structure in gas turbine-like combustors. The aimis to provide a comprehensive understanding of the complex combustion processes associated with these alternative fuels. The propagation of turbulent premixed flames under different density ratio conditions is investigatedusing direct numerical simulation (DNS). The displacement speed, which characterizes the self-propagation of an isosurface defined based on a reaction progress variable in a turbulent premixed flame, has gained significant interest in the scientific community for flame modeling purposes. In this thesis, a set of new transport equations for dilation and curvature-induced flame stretch rate is derived. Based on the set of evolution equations for displacement speed that takes into account the effects of curvature, normal diffusion, and reactions, this thesis analyzes the thermal expansion effect on the correlation between these quantities. The results reveal four scenarios of flame self-acceleration. The findings provide valuable insights into the understanding of the complex dynamics of turbulent premixed flames. A newly improved gas turbine model combustor, known as CeCOST burner, is the focus of an experimentalcampaign that involves laser-based diagnostics techniques, including simultaneous OH-/CH2O planar laser induced fluorescence (PLIF), simultaneous OH-PLIF, particle imaging velocimetry (PIV), and phosphor thermometry for surface temperature measurements. High-speed OH* chemiluminescence and exhaust gas measurements are also utilized. The results of the study reveal that hydrogen-enrichment can significantly extend the operation of methane/air to ultra-lean mixtures, resulting in low NOx emissions. The structures of the flame and the flow show significant variations with hydrogen-enrichment. Isolated flame pockets are identified in lean hydrogen-enriched methane/air flames, as well as in syngas flames where a substantial amount of hydrogen is present. The vortex breakdown structure is found to be strongly coupled with the location of the reaction zones. Furthermore, it is observed that pilot flames can enhance flame stabilization by producing hot gas and radicals that aid in anchoring the flames in the outer recirculation zone of the combustor. The findings of this study provide valuable insights into the combustion characteristics of methane/air, hydrogen-enriched methane/air, and syngas/air flames in the CeCOST burner, as well as the influence of pilot flames on flame and flow structures. These insights contribute to the development of more efficient and environmentally friendly gas turbine combustor designs

Atrial Fibrillation and Myocardial Infarction: A Systematic Review and Appraisal of Pathophysiologic Mechanisms

A growing body of evidence suggests that atrial fibrillation (AF) is associated with myocardial infarction (MI). However, incidence and management of MI in AF is still undefined. METHODS AND RESULTS: We searched MEDLINE via PubMed and Cochrane database between 1965 and 2015. All observational clinical studies and interventional trials reporting 1-year incidence of MI in AF were included. We also discussed pathophysiological mechanisms, predictors, and therapeutic approaches to reduce the risk of MI in AF. Twenty-one observational studies and 10 clinical trials were included. The annual rate of MI in observational studies including AF patients ranged from 0.4% to 2.5%. Higher rates of MI were reported in AF patients with stable coronary artery disease (11.5%/year), vascular disease (4.47%/year), heart failure (2.9%/year), and in those undergoing coronary artery interventions (6.3%/year). However, lower annual rates have been described in AF patients from Eastern countries (0.2-0.3%/year), and in those enrolled in clinical trials (from 0.4 to 1.3%/year). CONCLUSIONS: AF patients had a significant residual risk of MI despite anticoagulant treatment. Coexistence of atherosclerotic risk factors and platelet activation account for the increased risk of MI in AF. Identification of high-risk AF patients is a needed first step to develop cost-effective approaches for prevention. A new score, the 2MACE score, has been recently developed to stratify MI risk in AF, and may help not only in allocating resources to high-risk groups, but also in design of studies examining novel therapies for prevention of MI in AF

Atherothrombosis and Oxidative Stress: Mechanisms and Management in Elderly

Significance: The incidence of cardiovascular events (CVEs) increases with age, representing the main cause of death in an elderly population. Aging is associated with overproduction of reactive oxygen species (ROS), which may affect clotting and platelet activation, and impair endothelial function, thus predisposing elderly patients to thrombotic complications. Recent Advances: There is increasing evidence to suggest that aging is associated with an imbalance between oxidative stress and antioxidant status. Thus, upregulation of ROS-producing enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and myeloperoxidase, along with downregulation of antioxidant enzymes, such as superoxide dismutase and glutathione peroxidase, occurs during aging. This imbalance may predispose to thrombosis by enhancing platelet and clotting activation and eliciting endothelial dysfunction. Recently, gut-derived products, such as trimethylamine N-oxide (TMAO) and lipopolysaccharide, are emerging as novel atherosclerotic risk factors, and gut microbiota composition has been shown to change by aging, and may concur with the increased cardiovascular risk in the elderly. Critical Issues: Antioxidant treatment is ineffective in patients at risk or with cardiovascular disease. Further, anti-thrombotic treatment seems to work less in the elderly population. Future Directions: Interventional trials with antioxidants targeting enzymes implicated in aging-related atherothrombosis are warranted to explore whether modulation of redox status is effective in lowering CVEs in the elderly

Prática de ensino supervisionada, arte e design 8º ano

Elaborado no âmbito do Mestrado de Ensino em Artes Visuais no 3º Ciclo no Ensino Básico e no Ensino Secundário, este relatório relata a experiencia de estágio e investiga um paradigma pedagógico, umas das temáticas fundamentais do ensino das Artes Visuais: a Metodologia Projetual. A principal referência de apoio para a sua elaboração é a Prática de Ensino Supervisionada (PES) decorrida no ano letivo de 2011/2012, na Escola Secundária/3 Quinta das Palmeiras (ESQP) da Covilhã. O professor estagiário, Francesco Pignatelli, autor deste relatório, lecionou 56 aulas na disciplina opcional da componente de Educação Artística: Arte e Design (AD). A partir dessa experiencia, das planificações das aulas, das observações e reflexões constantemente elaboradas, produziu-se a presente investigação. Nas aulas de AD abordaram-se principalmente temáticas relacionadas à Arte e ao Design, nas suas diferentes formas e aspetos. Em específico, foram desenvolvidos Unidades de Trabalho (UT) com temas de estética, estrutura, forma, arte contemporânea, Eco-Design e Poesia Visual. O principal desafio da PES foi a definição de problemas por parte do professor estagiário, e sucessiva procura, por parte dos alunos, de estratégias projetuais para a resolução dos mesmos. Dessa forma o objetivo foi procurar que os alunos desenvolvessem competências na área projeto, em geral. A metodologia e o percurso adotado para a elaboração do relatório foi a planificação detalhada das aulas, a observação direta, a definição de um tema, a pesquisa bibliográfica, a elaboração de investigação e sucessiva fase de composição de todos os elementos. O relatório divide-se em três capítulos: no Capítulo I, faz-se um enquadramento geral da prática de estágio, uma caracterização geral da universidade, da escola, do grupo de estágio, do Mestrado, da disciplina lecionada e da turma; O Capítulo II, coração deste relatório, enquadra teoricamente e conceptualmente a pedagogia e a didática à base da PES, principalmente expondo a investigação desenvolvida, em todo os seus aspetos, apresentando resultados e reflexões; O Capítulo III expõe a prática de ensino e as atividades desenvolvidas, os resultados obtidos, uma reflexão crítica e apresenta eventuais propostas de melhoria. Por fim os apêndices e anexos contêm fichas de trabalhos, documentos orientadores da escola, material didático pedagógico, e outros documentos relevantes elaborados pelo autor deste relatório, em formato digital.In this thesis investigate an educational paradigm in teaching the Visual Arts, known as “the Project Methodology”. This investigation is based on a Supervised Teaching Practice (PES) which was done in the Escola 3/Quinta das Palmeiras (ESQP) in Covilhã, during the academic year 2011/2012. This program is based on studies during the teaching experiences by the trainee teacher, Francesco Pignatelli, during a teaching of 56 sessions of the optional lesson components in Art Education, namely “Art and Design (AD)”. The result is provided in terms of the initial lesson plans, the observations and reflections developed during the program. Different issues of Art and design was developed during these lessons from various perspectives such as in specific Work Units (WU), with themes of aesthetics, structure, contemporary art, eco-design and visual poetry. The main methodology of the PES in this project is defining some problems by the teacher, in the related issues of AD. Subsequently, solving those problems by demanding the students to use different strategies was the main goal herein, in order to develop their general skills in design. The method adopted for the report, was the detailed planning of lessons, the direct observation, the definition of a topic, the literature search, the investigation and the development of successive phase composition of all elements. The report is divided into three chapters: in Chapter I is a general framework for the practice stage, a characterization of the school, university, group stage, discipline and class; The second chapter, heart of this report, framed theoretically and conceptually pedagogy and of the discipline taught, and especially exposes its investigation; The third chapter explains the practice of teaching and the activities developed, the results obtained, and present proposals for improvement. Finally, the attachment contains school guide documents, teaching materials, and other relevant documents elaborated for the trainee teacher, in digital format

Aging-Related Decline of Glutathione Peroxidase 3 and Risk of Cardiovascular Events in Patients With Atrial Fibrillation

BACKGROUND: Experimental studies demonstrated that glutathione peroxidase 3 (GPx3), an antioxidant enzyme that catabolizes hydrogen peroxide, protects against thrombosis. Little is known about its role in cardiovascular disease. METHODS AND RESULTS: A prospective cohort study was conducted in 909 atrial fibrillation patients. Serum activities of GPx3, superoxide dismutase (SOD), and catalase were measured at baseline to assess the risk of cardiovascular events during a mean follow-up of 43.4 months (3291 person-years). Serum Nox2 and urinary excretion of 11-deydro-thromboxane B2 were also measured. During follow-up 160 cardiovascular events occurred (4.9%/year). Significantly lower values of GPx3 (P<0.001) and SOD (P=0.037) were detected in patients with, compared to those without, cardiovascular events. A lower survival rate was observed in patients with GPx3 (P<0.001) and SOD (P=0.010) activities below the median, as compared to those above. In a fully adjusted Cox regression model, GPx3 was the only antioxidant enzyme predictor of cardiovascular events (hazard ratio 0.647, 95% confidence interval 0.524-0.798, P<0.001). GPx3 was inversely associated with urinary 11-dehydro-thromboxane B2 (B -0.337, P<0.001) and serum Nox2 (B: -0.423, P<0.001). GPx3 activity progressively decreased with decades of age (P<0.001), with a progressive reduction in people aged ≥70 years. CONCLUSIONS: This study provides evidence that a low antioxidant status, as depicted by reduced levels of GPx3, increases the risk of cardiovascular events in patients with atrial fibrillation. The age-related decline of GPx3 may represent a mechanism for the enhanced cardiovascular risk in the elderly population

HIV-1 induces in vivo platelet activation by enhancing platelet NOX2 activity.

OBJECTIVES: HIV-1 patients show increased platelet activation, but the mechanisms involved are not completely clarified. We speculated that HIV-1 might induce in vivo platelet activation by enhancing platelet NOX2-related oxidative stress. METHODS: We measured soluble CD40 Ligand (sCD40L), a systemic marker of platelet activation, in 36 HIV-1 patients under effective combined antiretroviral therapy (cART) and in 10 naïve HIV-1 subjects. As control, 20 healthy subjects (HS) were included. Platelet oxidative stress was measured by platelet NOX2-derived peptide (sNOX2-dp), p47(phox) translocation to platelet membrane and platelet prostaglandin F2α (8-iso-PGF2α). RESULTS: sCD40L was increased both in HIV-1 naïve and cART patients compared to HS (p &lt; 0.001). Platelet sNOX2-dp and 8-iso-PGF2α were significantly higher in HIV-1 naïve subjects compared to those on cART and to HS, and both were mutually correlated (R = 0.734, p &lt; 0.001). A stepwise multivariable linear regression analysis showed that platelet sNOX2-dp (β: 0.803, p &lt; 0.001), HIV-1 infection (β: 0.146, p = 0.014) and age (β: 0.166, p = 0.001) were independently associated to sCD40L levels. CONCLUSIONS: HIV-1 infection is associated with increased platelet oxidative stress, which was related to the activation of NOX2. The independent association between platelet NOX2 activation and plasma levels of sCD40L suggest that in vivo platelet activation may be dependent upon platelet oxidative stress

Design of location-enabled e-government services

This document provides guidance on the design of location enabled e-Government services. It is part of the European Union Location Framework (EULF) toolkit that helps Member States to improve the use of location information in the context of e-Government. The document explains what location enabled e-Government services are, and how they can support the many G2G, G2B and G2C process interactions. Examples are given for the different types of e-Government services: information, contact, transaction, participation and data transfer services (Bekkers, 2007a). The document also provides an approach to describe and document e-Government business processes as a starting point for identifying where location enabled e-Government services could add value to the process by using process modelling techniques and standards. Finally, the document explains in detail the organisational and technological aspects related to the design, implementation and evaluation of location enabled e-Government services. A series of recommendations are provided in the form of ‘to-do’s’ and ‘not-to-do’s’. Examples are given throughout the text to illustrate best practices. This document should be read in conjunction with the companion guidance document “EULF Improving the use of location information in e-government processes: methodology and use case”, which provides a methodology and worked example of improving an existing process.JRC.B.6-Digital Econom

Extra virgin olive oil use is associated with improved post-prandial blood glucose and LDL cholesterol in healthy subjects

Extra virgin olive oil (EVOO) is a key component of the Mediterranean diet and seems to account for the protective effect against cardiovascular disease. However, the underlying mechanism is still elusive

Similar reduction of cholesterol-adjusted Vitamin E serum levels in simple steatosis and non-alcoholic steatohepatitis

OBJECTIVES: Reduced vitamin E levels have been reported in patients with non-alcoholic steatohepatitis (NASH), but no conclusive data on patients with simple steatosis (SS) are available. Aim of this study was to investigate the association betweenserum vitamin E levels and SS. METHODS: A cohort of 312 patients with cardio-metabolic risk factors was screened for liver steatosis by ultrasonography (US). We reasonably classified as SS patients with US-fatty liver, normal liver function tests (LFTs) and with Cytokeratin 18 o246 mIU/ml. Liver biopsy was performed in 41 patients with US-fatty liver and persistent elevation of LFTs (46 months). Serum cholesterol-adjusted vitamin E (Vit E/chol) levels were measured. RESULTS: Mean age was 53.9±12.5 years and 38.4% were women. Non-alcoholic fatty liver disease (NAFLD) was detected at US in 244 patients; of those 39 had biopsy-proven NASH and 2 borderline NASH. Vit E/chol was reduced in both SS (3.4±2.0, Po0.001), and NASH (3.5±2.1, P=0.006) compared with non-NAFLD patients (4.8±2.0 μmol/mmol chol). No difference was found between SS and NASH (P=0.785). After excluding patients with NASH, a multivariable logistic regression analysis found that Vit E/chol (odds ratio (OR): 0.716, 95% confidence interval (CI) 0.602–0.851, Po0.001), alanine aminotransferase (ALT, OR: 1.093, 95% CI 1.029–1.161, P=0.004), body mass index (OR: 1.162, 95% CI 1.055–1.279, P=0.002) and metabolic syndrome (OR: 5.725, 95% CI 2.247–14.591, Po0.001) were factors independently associated with the presence of SS. CONCLUSIONS: Reduced vitamin E serum levels are associated with SS, with a similar reduction between patients with SS and NASH, compared with non-NAFLD patients. Our findings suggest that the potential benefit of vitamin E supplementation should be investigated also in patients with SS