Combustion analysis on a CFM56-3 engine

The more fuel efficient an engine is, the less fuel is needed to get from point A to point B and the less Greenhouse gases will be produced. In spite of being a major source of carbon dioxide, gas turbine engines lead the aircraft propulsion systems globally and will probably continue for the next decades. Thus, one of the most immediate ways to go green on the skies is by advancing their performance. Nontheless, GTE’s are one of the most complex engineering problems, as they rely on hundreds of parameters that can be tweaked and result in a better configuration. However, we have computers and softwares that allow us to test engine concepts. This study consisted in a numerical analyses of the combustion of Jet-A in the annular combustor of the CFM56-3 engine, through two different turbulence models. The geometry used was ¼ of the engine constructed by Jonas Oliveira by performing a 3D scan on a real size combustor. This geometry was imported and prepared in a CFD software, CONVERGE Studio, where the case setup was configured. The simulation itself was run on the main software CONVERGE installed on a multi-core high performance machine. The final goal of this study was to compare the behavior of each turbulence model when studying the performance of annular combustors similar to the most popular turbofan engine’s. The turbulence models chosen were the standard ??-?? and the standard ??-?? and also a set of models were defined to simulate the injection of fuel through a parcel spray and, therefore, better predict the flow inside the combustor. To compare the simulation results, six main parameters were analysed: Turbulent Kinematic Energy (??); Turbulence Dissipation Rate (??); Specific Turbulence Dissipation Rate (??); Turbulent Length Scale (??); Friction Velocity (??*); and the dimensionless wall distance (??+). Both models demonstrated a similar behavior in all the parameters, along the runtime. The results were all within the same order of magnitude, although the absolute values have shown a considerable difference. The simulation outputs were considered acceptable after comparing quantitatively the exhaust parameters, and qualitatively a temperature and TKE contour with two previous works with similar setup conditions. Any turbulence model was judged better than the other, due to the complexity involved in such a study, but only considered different.Quanto mais eficiente um motor é, menos combustível é necessário para ir de um ponto A para um ponto B e menos gases de efeito estufa são produzidos. Apesar de serem uma fonte de dióxido de carbono significante, os motores de turbina de gás lideram os sistemas de propulsão aeronáutica e provavelmente assim vão continuar nas próximas décadas. Portanto, uma das formas mais rápidas de procurar ser sustentável nos céus é melhorando a sua performance. Todavia, estes motores representam um dos mais complexos problemas de engenharia, uma vez que dependem de centenas de diferentes parâmetros que ao variarem podem levar a que surja uma configuração melhor. No entanto, disponibilizamos de computadores e softwares capazes de testar diferentes conceitos. Este trabalho consistiu em uma análise numérica da combustão de Jet-A no combustor anular do CFM56-3, através de dois modelos de turbulência diferentes. A geometria utilizada foi ¼ do motor construído pelo Jonas Oliveira, ao realizer um scan 3D a um combustor real. Esta geometria foi importada para um software de CFD, CONVERGE Studio, onde todos os parâmetros dos ensaios foram configurados. A simulação em sim foi realizada no software principal CONVERGE, instalado num computador de alto desempenho. O objetivo final deste estudo passou pela comparação do comportamento de cada modelo de turbulência, enquanto estudamos a performance de um dos mais populares motores turbofan. Os modelos de turbulência escolhidos foram o standard ??-?? e o standard ??-??, para além de ter sido selecionado um conjunto de modelos para simular a injeção de combustível através de vaporização, de modo a prever melhor o comportamento do escoamento dentro do combustor. De forma a comparar estes modelos, seis parâmetros principais foram analisados: a enregia cinética turbulenta (??); a taxa de dissipação da energia cinética turbulenta (??); a dissipação da energia cinética turbulenta específica (??); o comprimento característico dos turbilhões (??); a velocidade de fricção (??*); e a distãncia adimensional à parede (??+). Ambos os modelos mostraram um comportamento semelhante ao longo do tempo para todos os parâmetros. Todos os resultados encontram-se na mesma ordem de grandeza, apesar apresentarem uma diferença considerável no seu valor absoluto. Os mesmos foram considerados aceitáveis, após uma comparação quantitativa com parâmetros à saída do combustor e uma comparação qualitativa de um perfil de temperaturas e de um perfil de energia cinética turbulenta com dois estudos de configurações similares. Por fim, nenhum modelo foi classificado melhor que o outro, devido à complexidade envolvida num estudo deste tipo, mas apenas considerados diferentes

Nas malhas dos poderes e contrapoderes dos técnicos de radiologia nos hospitais públicos portugueses

As administrações dedicam-se a um "novo managerialismo" que procura maximizar a eficiência, economia e eficácia e, como subproduto, suplantar a autoridade intermédia introduzindo mudanças de cima para baixo. Os discursos do managerialismo/Nova Gestão Pública (NGP) têm invadido de forma seletiva as linhas de orientação das práticas dos profissionais de saúde. Segundo Carvalho (2006), em Portugal, tais ações managerialistas nos hospitais do sector público, apoiadas numa lógica de gestão racional dos valores e normas do sector privado para promover alterações e/ou reformas estruturais na organização do trabalho, têm procurado efetivar em primeira e em última instância, institucionalizar certas mudanças, ajustamentos, adaptações, regulações e mecanismos de controlo capazes de dinamizar novas orientações culturalistas e comportamentais dos profissionais de saúde. Também a limitação intrínseca da divisão do trabalho condicionada pelo ato médico, concorre com a redução do campo de intervenção dos técnicos de radiologia. Seguindo a perspetiva de Foucault sobre a ideia de governação, enquanto necessidade de associar formas de conhecimento cada vez mais específicas e exigentes, gerando aquilo que se define como a “institucionalização da expertise” (Johnson, 1995:7), os conquistam a desejada autonomia profissional através de uma metodologia, Pratica Baseada na Evidência, que apela à padronização dos procedimentos, relegando para segundo plano a intervenção direta de outros profissionais

Assessing the hospital survey of patient safety culture. A review of the assumptions, methods and data analysis protocol

Patient safety theme is becoming one of the most discussed theme in healthcare facilities, mainly at hospitals. The main aim of this paper was to present a review of the structure Hospital Survey on Patient Safety Culture model (HSOPSC) and analyze in a brief summary of the main researches that were developed recently using this survey model to explain the patient safety culture dimensions. This instrument was created by the Agency for Healthcare Research and Quality (AHRQ) and became a survey commonly used in the United States of America and increasingly used internationally, with or without adaptations

Improving patient health literacy in imaging departments

Health Literacy is a key issue in the healthcare and its operational definition developed for the National Library of Medicine mention that is the “the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions” 1. Health literacy skills are needed for dialogue and discussion, reading health information, making decisions about participating in research activities, using medical tools for personal or familial health care, and even for voting on health or environmental...info:eu-repo/semantics/publishedVersio

The paradigm shift in medical imaging education and training in Europe

The main goal of this literature review is to discuss the emerging trends, challenges and opportunities in the field of medical imaging education in Europe due to the Covid-19 pandemic scenario that forced the remodeling of the teaching and learning process. A bibliographic search was carried out in the main databases and from resources available in scientific and professional associations in Europe. Exclusion criteria included articles without contributions on distance learning or active learning. Education and training in medical imaging field had to readapt and the usual opportunities for medical imaging and radiotherapy (MIR) students to learn in person in the classroom, lab and clinical settings, had to be quickly transformed into distance learning opportunities. Thus, online education became a pedagogical shift from traditional method to the modern approach of teaching and learning from classroom to Zoom, from personal to virtual and from seminars to webinars, leading to the emergence of innovative teaching models. Moreover, student-centered strategies such as flipped classroom and game-based learning have been recently applied in health professions education with positive and very promising results. In conclusion, due to the pandemic crisis, MIR educators and students find themselves in the situation where they felt compelled to embrace the digital academic experience, allowing the progressive innovation of e-learning. In this context, game-based learning appears to be effective for improving knowledge, skills, attitudes and satisfaction and should be considered as a potential systematic tool in the field of medical imaging education. Therefore, preparedness of radiographers depends on the application of effective training and education methodologies that allows excellent clinical performance and maintaining high quality and safety standards, both through undergraduate course and continuous professional development.info:eu-repo/semantics/publishedVersio

Fat quantification using computerized tomography

The purpose of this research was to quantify the volume of subcutaneous fat, visceral fat and intramuscular fat of patients that underwent computerized tomography examinations and relate this to age, gender, weight, height, waist circumference and body mass index.info:eu-repo/semantics/publishedVersio

Quality in computorized tomography: from image acquisition to dose, concepts, myths and definitions

With this review article, we intend to demonstrate the importance of Computerized Tomography (CT) in healthcare quality and safety. The concept of safety in CT is wider than for general healthcare. Safe healthcare provided using CT must include diagnostic image quality and reliability, as this is the only way to ensure diagnostic accuracy. The images must be acquired with the most adequate protocols available and with the lowest achievable radiation dose. In this article we will focus primarily on the concepts of dose, since this variable strongly affects the image quality and the consequent diagnostic accuracy. In methodological terms, 73 papers and 6 catalogues issued by the manufacturers of CT equipment, that included the keywords low dose, ultra-low dose and dose reduction were analysed. After review of these articles we found that about 82% are chest exams, namely the lungs. The remaining were subdivided mainly by studies of the sinuses, heart and bone segments. After this review we selected the only 10 articles that present the keywords and simultaneously quantify the dose reduction. Given the lack of precision associated with these terms, introduced mainly by commercial catalogues of different equipment brands, we intend to demonstrate that the concepts low dose and ultra-low dose are wrapped in unclear marketing strategies, without a strict and unambiguous definition of what is the effective dose. We propose that these concepts should be clearly defined and a precise indication of the effective dose reduction value should be compared to the default value (standard diagnostic dose) by exam region. Therefore, it is demonstrated that there is no concrete definition of what low dose or ultra-low dose are. These slogans cannot be used until they are not holistically defined, as well as the correspondent dose reduction value.info:eu-repo/semantics/publishedVersio

Residual activity in a Nuclear Medicine Department: a dosimetric study

The exposure to ionizing radiation by radiographer in Nuclear Medicine (NM) Departments is inevitable, as this area has the highest rates of residual activity. Since 1957, and later updated (2005), several guidelines have been established by the IAEA (International Atomic Energy Agency), for the management of residues from radioactive use for medical purposes, with the intention of increasing the radiological protection of the people and the environment. Optimized management is very important not only for the functioning of the NM department, but also for the...info:eu-repo/semantics/publishedVersio

Effect of native gastric mucus on in vivo hybridization therapies directed at Helicobacter pylori

Helicobacter pylori infects more than 50% of the worldwide population. It is mostly found deep in the gastric mucus lining of the stomach, being a major cause of peptic ulcers and gastric adenocarcinoma. To face the increasing resistance of H. pylori to antibiotics, antimicrobial nucleic acid mimics are a promising alternative. In particular, locked nucleic acids (LNA)/2'-OMethyl RNA (2'OMe) have shown to specifically target H. pylori, as evidenced by in situ hybridization. The success of in vivo hybridization depends on the ability of these nucleic acids to penetrate the major physical barriers-the highly viscoelastic gastric mucus and the bacterial cell envelope. We found that LNA/2'OMe is capable of diffusing rapidly through native, undiluted, gastric mucus isolated from porcine stomachs, without degradation. Moreover, although LNA/2'OMe hybridization was still successful without permeabilization and fixation of the bacteria, which is normally part of in vitro studies, the ability of LNA/2'OMe to efficiently hybridize with H. pylori was hampered by the presence of mucus. Future research should focus on developing nanocarriers that shield LNA/2'OMe from components in the gastric mucus, while remaining capable of diffusing through the mucus and delivering these nucleic acid mimics directly into the bacteria

Clinical diagnostic reference levels in computed tomography examinations

For the accomplishment of this study, CT dose descriptors such as mAs, kVp, Computed Tomography Dose Index (CTDI) and Dose Length Product (DLP) were registered for CT examinations of the brain, face, chest, spine, abdomen and pelvis, through the examination of the file dose protocol grouped into 12 different clinical indications and using a sample of 20 patients per each clinical indication. A final total of 240 examinations were considered.info:eu-repo/semantics/publishedVersio