Multidisciplinary assessment of a year 2035 turbofan propulsion system

A conceptual design of a year 2035 turbofan is developed and integrated onto a year 2035 aircraft model. The mission performance is evaluated for CO2, noise and NOx and is compared with a notional XWB/A350-model. An OGV heat exchanger is then studied rejecting heat from an electric generator, and its top-level performance is evaluated. The fan, the booster and the low-pressure turbine of the propulsion system are subject to more detailed aero design based on using commercial design tools and CFD-optimization. Booster aerodynamic modelling output is introduced back into the performance model to study the integrated performance of the component. The top-level performance aircraft improvements are compared to top-level-trends and ICAO estimates of technology progress potential, attempting to evaluate whether there is some additional margin for efficiency improvement beyond the ICAO technology predictions for the same time frame

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Development of Accurate Reduced Order Models in a Simulation Tool for Turbomachinery Aeromechanical Phenomena

Modern gas turbines are still vulnerable to vibrations when operated at certain speeds. This unstable environment can lead to high cycle fatigue (HCF) and damage several of the components inside the turbine. Since engineers are striving to increase the turbines’ efficiency with thinner and more complex blade shapes, these critical speeds will always be present. For these reasons, aeromechanical analyses that is the study of structural and aerodynamic forces need to be assessed with a high level of accuracy. Since this type of analysis are very computational expensive, reduced order models (ROMs) are utilized to decrease the degrees of freedom (DoF) for a faster computation without compromising the accuracy. The present work focuses on cyclic and noncyclic ROMs implemented in an already existing aeroelastic tool, with different characteristics in their condensation and ease of usage depending on the analysis.   The AROMA (Aeroelastic Reduced Order Model Analysis) tool has been previously developed to predict the fatigue life of turbomachinery blades with the use of ROMs. The aim of this work has been to improve the tool in terms of accuracy, flexibility and speed, by employing additional reduction methods capable to predict forced responses analysis of large industrial-size models.   The understanding of an aeroelastic phenomena would not be complete if mistuning is not considered in the analysis. A mistuned bladed-disk means that all its sectors do not share the same mass and stiffness properties, which in reality this is the case. Mistuning can be addressed as probabilistic, taking into account the manufacturing tolerances and wear of the bladed disk, or it can be assessed as deterministic, also known as intentional mistuning.   The latter is achieved to increase the flutter stability by breaking the circumferential traveling waves modes due to energy confinement, and also to have a certain understanding of the forced response amplitude, which helps in designing for worst and best case scenarios.   The ROMs that have been incorporated in the AROMA tool are known as the component mode synthesis (CMS) and subset nominal mode (SNM) approaches. The CMS is split into two branches, these are the fixed- and freeinterface methods known as Craig-Bampton (CB) and Craig-Chang (CC), respectively. An intensive study with numerical and experimental validation has been performed for these three reduction methods. The outcome of the study is that each of these methods have their own drawbacks and benefits depending on the aeromechanical analysis problem. The SNM showed that it produces fast computations, with high level of accuracy when the mistuning level is low. On the other hand, a novel and unique approach, Craig-Chang multisubstructuring (CCMS), demonstrated fast computations and high accuracy when the mistuning level is high.QC 20180514</p

Development of Accurate Reduced Order Models in a Simulation Tool for Turbomachinery Aeromechanical Phenomena

Modern gas turbines are still vulnerable to vibrations when operated at certain speeds. This unstable environment can lead to high cycle fatigue (HCF) and damage several of the components inside the turbine. Since engineers are striving to increase the turbines’ efficiency with thinner and more complex blade shapes, these critical speeds will always be present. For these reasons, aeromechanical analyses that is the study of structural and aerodynamic forces need to be assessed with a high level of accuracy. Since this type of analysis are very computational expensive, reduced order models (ROMs) are utilized to decrease the degrees of freedom (DoF) for a faster computation without compromising the accuracy. The present work focuses on cyclic and noncyclic ROMs implemented in an already existing aeroelastic tool, with different characteristics in their condensation and ease of usage depending on the analysis.   The AROMA (Aeroelastic Reduced Order Model Analysis) tool has been previously developed to predict the fatigue life of turbomachinery blades with the use of ROMs. The aim of this work has been to improve the tool in terms of accuracy, flexibility and speed, by employing additional reduction methods capable to predict forced responses analysis of large industrial-size models.   The understanding of an aeroelastic phenomena would not be complete if mistuning is not considered in the analysis. A mistuned bladed-disk means that all its sectors do not share the same mass and stiffness properties, which in reality this is the case. Mistuning can be addressed as probabilistic, taking into account the manufacturing tolerances and wear of the bladed disk, or it can be assessed as deterministic, also known as intentional mistuning.   The latter is achieved to increase the flutter stability by breaking the circumferential traveling waves modes due to energy confinement, and also to have a certain understanding of the forced response amplitude, which helps in designing for worst and best case scenarios.   The ROMs that have been incorporated in the AROMA tool are known as the component mode synthesis (CMS) and subset nominal mode (SNM) approaches. The CMS is split into two branches, these are the fixed- and freeinterface methods known as Craig-Bampton (CB) and Craig-Chang (CC), respectively. An intensive study with numerical and experimental validation has been performed for these three reduction methods. The outcome of the study is that each of these methods have their own drawbacks and benefits depending on the aeromechanical analysis problem. The SNM showed that it produces fast computations, with high level of accuracy when the mistuning level is low. On the other hand, a novel and unique approach, Craig-Chang multisubstructuring (CCMS), demonstrated fast computations and high accuracy when the mistuning level is high.QC 20180514</p

Blade oscillation mechanism for aerodynamic damping measurements at high reduced frequencies

Accurate prediction of aerodynamic damping is essential for flutter and forced response analysis of turbomachinery components. Reaching a high level of confidence in numerical simulations requires that the models have been validated against the experiments. Even though a number of test cases have been established over the past decades, there is still a lack of suitable detailed test data that can be used for validation purposes in particular when it comes to aero damping at high reduced frequencies which is more relevant in the context of forced response analysis. A new transonic cascade test rig, currently undergoing commissioning at KTH, has been designed with the goal to provide detailed blade surface unsteady pressure data for compressor blades profiles oscillating at high reduced frequencies. The paper provides an overview of the blade actuation system employed in the test rig and presents the result of a series of bench tests characterizing the blade vibration amplitudes achieved with this actuation system

Presencia del marcador lmp-1 del virus epstein barr en linfomas de caninos

Epstein Barr virus (EBV) is a humans’ high prevalent virus associated with lymphoid B cells tumors development. In canines, few reports have been published regarding the presence of the virus in dogs but its role in this species remain unclear.  The aim of this study was to determine the presence of LMP-1 protein of EBV in 20 canine lymphomas tissues which were previously diagnosed in a period of time between 2004 -2014.  Lymphomas were reclassified in accordance with the new histopathological classifications for lymphomas and were stained by IHQ with anti-CD79a, anti-CD3 and anti-LMP1; specific antibodies for B lymphocytes, T lymphocytes and EBV biomarker respectively.  As a result, it was found that the most common lymphoma was T-zone lymphoma in 75% of the cases of the study. The distribution of the cases regarding the immunostaining were: 18 positive cases with anti- CD3, 2 positive cases with anti-CD79a and 6 positive cases with anti-LMP-1.  Positive cases of LMP1 as a biomarker of the presence of EBV corresponded to the 30% of the cases of the study. Chi-square test showed statistical significance between the presence of the virus and the presence of lymphomas, which suggests not only that the virus is circulating in the canine population but also that could have implications in the development of the disease. Regarding demographic parameters, only the Golden Retriever breed showed a relationship with the presence of lymphoma, but not with the presence of the virus.El virus Epstein Barr (EBV) es un virus con alta prevalencia en humanos relacionado con tumores de la línea linfoide B. En caninos, pocos reportes se tienen de él, lo que llevó a realizar este estudio en donde se buscó determinar su presencia en tejidos obtenidos de 20 linfomas de caninos cuyo diagnóstico se había realizado durante un periodo de 10 años, entre el 2004 y el 2014. Para iniciar el estudio los linfomas se reclasificaron de acuerdo con las nuevas clasificaciones histopatológicas para linfomas y se inmunomarcaron con los anticuerpos anti-CD79a, anticuerpo específico para linfocito B, anti-CD3, específico para linfocito T y un anti-LMP-1 marcador de la proteína temprana del EBV. Como resultados se encontró que los linfomas más comunes fueron el linfoma nodal de zona T en un 75% de los casos. Al realizar la inmunomarcación se encontraron 18 casos positivos a CD3, 2 casos positivos a CD79a y 6 casos positivos a LMP-1 lo que representa el 30% de positividad del EBV en linfomas. El análisis estadístico aplicado de Ji cuadrado demostró significancia estadística entre la presencia del virus y la presencia del linfoma, lo que sugiere no solamente que el virus está circulando en la población canina sino que además puede tener una relación con la presencia del esta neoplasia. Respecto a las variables demográficas, sólo la raza Golden Retriever mostró relación con la presencia del linfoma, pero no con la presencia del virus

Presencia del marcador lmp-1 del virus epstein barr en linfomas de caninos

El virus Epstein Barr (EBV) es un virus con alta prevalencia en humanos relacionado con tumores de la línea linfoide B. En caninos, pocos reportes se tienen de él, lo que llevó a realizar este estudio en donde se buscó determinar su presencia en tejidos obtenidos de 20 linfomas de caninos cuyo diagnóstico se había realizado durante un periodo de 10 años, entre el 2004 y el 2014. Para iniciar el estudio los linfomas se reclasificaron de acuerdo con las nuevas clasificaciones histopatológicas para linfomas y se inmunomarcaron con los anticuerpos anti-CD79a, anticuerpo específico para linfocito B, anti-CD3, específico para linfocito T y un anti-LMP-1 marcador de la proteína temprana del EBV. Como resultados se encontró que los linfomas más comunes fueron el linfoma nodal de zona T en un 75% de los casos. Al realizar la inmunomarcación se encontraron 18 casos positivos a CD3, 2 casos positivos a CD79a y 6 casos positivos a LMP-1 lo que representa el 30% de positividad del EBV en linfomas. El análisis estadístico aplicado de Ji cuadrado demostró significancia estadística entre la presencia del virus y la presencia del linfoma, lo que sugiere no solamente que el virus está circulando en la población canina sino que además puede tener una relación con la presencia del esta neoplasia. Respecto a las variables demográficas, sólo la raza Golden Retriever mostró relación con la presencia del linfoma, pero no con la presencia del virus.Epstein Barr virus (EBV) is a humans’ high prevalent virus associated with lymphoid B cells tumors development. In canines, few reports have been published regarding the presence of the virus in dogs but its role in this species remain unclear.  The aim of this study was to determine the presence of LMP-1 protein of EBV in 20 canine lymphomas tissues which were previously diagnosed in a period of time between 2004 -2014.  Lymphomas were reclassified in accordance with the new histopathological classifications for lymphomas and were stained by IHQ with anti-CD79a, anti-CD3 and anti-LMP1; specific antibodies for B lymphocytes, T lymphocytes and EBV biomarker respectively.  As a result, it was found that the most common lymphoma was T-zone lymphoma in 75% of the cases of the study. The distribution of the cases regarding the immunostaining were: 18 positive cases with anti- CD3, 2 positive cases with anti-CD79a and 6 positive cases with anti-LMP-1.  Positive cases of LMP1 as a biomarker of the presence of EBV corresponded to the 30% of the cases of the study. Chi-square test showed statistical significance between the presence of the virus and the presence of lymphomas, which suggests not only that the virus is circulating in the canine population but also that could have implications in the development of the disease. Regarding demographic parameters, only the Golden Retriever breed showed a relationship with the presence of lymphoma, but not with the presence of the virus

Dominance of Three Sublineages of the SARS-CoV-2 Delta Variant in Mexico

In this study, we analyzed the sequences of SARS-CoV-2 isolates of the Delta variant in Mexico, which has completely replaced other previously circulating variants in the country due to its transmission advantage. Among all the Delta sublineages that were detected, 81.5 % were classified as AY.20, AY.26, and AY.100. According to publicly available data, these only reached a world prevalence of less than 1%, suggesting a possible Mexican origin. The signature mutations of these sublineages are described herein, and phylogenetic analyses and haplotype networks are used to track their spread across the country. Other frequently detected sublineages include AY.3, AY.62, AY.103, and AY.113. Over time, the main sublineages showed different geographical distributions, with AY.20 predominant in Central Mexico, AY.26 in the North, and AY.100 in the Northwest and South/Southeast. This work describes the circulation, from May to November 2021, of the primary sublineages of the Delta variant associated with the third wave of the COVID-19 pandemic in Mexico and highlights the importance of SARS-CoV-2 genomic surveillance for the timely identification of emerging variants that may impact public health