Radial turbine sound and noise characterisation with acoustic transfer matrices by means of fast one-dimensional models

This is the author's version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087419889429.[EN] Estimating correctly the turbine acoustics can be valuable during the engine design stage; in fact, it can lead to a more optimised design of the silencer and aftertreatment, as well as to better prediction of the scavenging effects. However, obtaining the sound and noise emissions of radial turbocharger turbines with low computational costs can be challenging. To consider these effects in a time-efficient manner, the acoustic response of single-entry radial turbines can be characterised by means of acoustic transfer matrices that change with the operating conditions. Exploiting the different time-scales of the acoustic phenomena and the change in the operating point of the turbine, lookup tables of acoustic transfer matrices can be computed. Then, the obtained characterisation can be used in mean-value engine models. This article presents a method for generating these lookup tables by means of fast one-dimensional simulations of thoroughly validated fidelity, in terms of both acoustics and extrapolation capabilities. Due to the inherent behaviour of radial turbines, the number of computations needed to fill the lookup tables is relatively small, so the method can be used as a simple preprocessing phase before mean-value simulation campaigns.Torregrosa, AJ.; García-Cuevas González, LM.; Inhestern, LB.; Soler-Blanco, P. (2021). Radial turbine sound and noise characterisation with acoustic transfer matrices by means of fast one-dimensional models. International Journal of Engine Research. 22(4):1312-1328. https://doi.org/10.1177/1468087419889429S13121328224Broatch, A., Galindo, J., Navarro, R., & García-Tíscar, J. (2014). Methodology for experimental validation of a CFD model for predicting noise generation in centrifugal compressors. International Journal of Heat and Fluid Flow, 50, 134-144. doi:10.1016/j.ijheatfluidflow.2014.06.006Galindo, J., Tiseira, A., Navarro, R., Tarí, D., & Meano, C. M. (2017). Effect of the inlet geometry on performance, surge margin and noise emission of an automotive turbocharger compressor. Applied Thermal Engineering, 110, 875-882. doi:10.1016/j.applthermaleng.2016.08.099Peat, K. S., Torregrosa, A. J., Broatch, A., & Fernández, T. (2006). An investigation into the passive acoustic effect of the turbine in an automotive turbocharger. Journal of Sound and Vibration, 295(1-2), 60-75. doi:10.1016/j.jsv.2005.11.033Torregrosa, A., Galindo, J., Serrano, J. R., & Tiseira, A. (2009). A Procedure for the Unsteady Characterization of Turbochargers in Reciprocating Internal Combustion Engines. Fluid Machinery and Fluid Mechanics, 72-79. doi:10.1007/978-3-540-89749-1_10Torregrosa, A. J., Broatch, A., Navarro, R., & García-Tíscar, J. (2014). Acoustic characterization of automotive turbocompressors. International Journal of Engine Research, 16(1), 31-37. doi:10.1177/1468087414562866Broatch, A., Galindo, J., Navarro, R., García-Tíscar, J., Daglish, A., & Sharma, R. K. (2015). Simulations and measurements of automotive turbocharger compressor whoosh noise. Engineering Applications of Computational Fluid Mechanics, 9(1), 12-20. doi:10.1080/19942060.2015.1004788Broatch, A., Galindo, J., Navarro, R., & García-Tíscar, J. (2016). Numerical and experimental analysis of automotive turbocharger compressor aeroacoustics at different operating conditions. International Journal of Heat and Fluid Flow, 61, 245-255. doi:10.1016/j.ijheatfluidflow.2016.04.003Wallace, F. J., & Adgey, J. (1967). Paper 1: Theoretical Assessment of the Non-Steady Flow Performance of Inward Radial Flow Turbines. Proceedings of the Institution of Mechanical Engineers, Conference Proceedings, 182(8), 22-36. doi:10.1243/pime_conf_1967_182_211_02Piscaglia, F., Onorati, A., Marelli, S., & Capobianco, M. (2018). A detailed one-dimensional model to predict the unsteady behavior of turbocharger turbines for internal combustion engine applications. International Journal of Engine Research, 20(3), 327-349. doi:10.1177/1468087417752525Galindo, J., Fajardo, P., Navarro, R., & García-Cuevas, L. M. (2013). Characterization of a radial turbocharger turbine in pulsating flow by means of CFD and its application to engine modeling. Applied Energy, 103, 116-127. doi:10.1016/j.apenergy.2012.09.013Galindo, J., Tiseira, A., Fajardo, P., & García-Cuevas, L. M. (2014). Development and validation of a radial variable geometry turbine model for transient pulsating flow applications. Energy Conversion and Management, 85, 190-203. doi:10.1016/j.enconman.2014.05.072Avola, C., Copeland, C., Romagnoli, A., Burke, R., & Dimitriou, P. (2017). Attempt to correlate simulations and measurements of turbine performance under pulsating flows for automotive turbochargers. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 233(2), 174-187. doi:10.1177/0954407017739123Galindo, J., Climent, H., Tiseira, A., & García-Cuevas, L. M. (2016). Effect of the numerical scheme resolution on quasi-2D simulation of an automotive radial turbine under highly pulsating flow. Journal of Computational and Applied Mathematics, 291, 112-126. doi:10.1016/j.cam.2015.02.025Serrano, J. R., Arnau, F. J., García-Cuevas, L. M., Dombrovsky, A., & Tartoussi, H. (2016). Development and validation of a radial turbine efficiency and mass flow model at design and off-design conditions. Energy Conversion and Management, 128, 281-293. doi:10.1016/j.enconman.2016.09.032Galindo, J., Navarro, R., García-Cuevas, L. M., Tarí, D., Tartoussi, H., & Guilain, S. (2018). A zonal approach for estimating pressure ratio at compressor extreme off-design conditions. International Journal of Engine Research, 20(4), 393-404. doi:10.1177/1468087418754899Payri, F., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2014). External heat losses in small turbochargers: Model and experiments. Energy, 71, 534-546. doi:10.1016/j.energy.2014.04.096Serrano, J. R., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2015). Turbocharger heat transfer and mechanical losses influence in predicting engines performance by using one-dimensional simulation codes. Energy, 86, 204-218. doi:10.1016/j.energy.2015.03.130Serrano, J. R., Olmeda, P., Tiseira, A., García-Cuevas, L. M., & Lefebvre, A. (2013). Theoretical and experimental study of mechanical losses in automotive turbochargers. Energy, 55, 888-898. doi:10.1016/j.energy.2013.04.042Piñero, G., Vergara, L., Desantes, J. M., & Broatch, A. (2000). Estimation of velocity fluctuation in internal combustion engine exhaust systems through beamforming techniques. Measurement Science and Technology, 11(11), 1585-1595. doi:10.1088/0957-0233/11/11/307Galindo, J., Serrano, J. R., Arnau, F. J., & Piqueras, P. (2009). Description of a Semi-Independent Time Discretization Methodology for a One-Dimensional Gas Dynamics Model. Journal of Engineering for Gas Turbines and Power, 131(3). doi:10.1115/1.2983015Serrano, J. R., Arnau, F. J., Dolz, V., Tiseira, A., & Cervelló, C. (2008). A model of turbocharger radial turbines appropriate to be used in zero- and one-dimensional gas dynamics codes for internal combustion engines modelling. Energy Conversion and Management, 49(12), 3729-3745. doi:10.1016/j.enconman.2008.06.031Serrano, J. R., Tiseira, A., García-Cuevas, L. M., Inhestern, L. B., & Tartoussi, H. (2017). Radial turbine performance measurement under extreme off-design conditions. Energy, 125, 72-84. doi:10.1016/j.energy.2017.02.118Welch, P. (1967). The use of fast Fourier transform for the estimation of power spectra: A method based on time averaging over short, modified periodograms. IEEE Transactions on Audio and Electroacoustics, 15(2), 70-73. doi:10.1109/tau.1967.1161901Serrano, J. R., Arnau, F. J., García-Cuevas, L. M., & Inhestern, L. B. (2019). An innovative losses model for efficiency map fitting of vaneless and variable vaned radial turbines extrapolating towards extreme off-design conditions. Energy, 180, 626-639. doi:10.1016/j.energy.2019.05.062Van Leer, B. (1974). Towards the ultimate conservative difference scheme. II. Monotonicity and conservation combined in a second-order scheme. Journal of Computational Physics, 14(4), 361-370. doi:10.1016/0021-9991(74)90019-9Toro, E. F., Spruce, M., & Speares, W. (1994). Restoration of the contact surface in the HLL-Riemann solver. Shock Waves, 4(1), 25-34. doi:10.1007/bf01414629Courant, R., Friedrichs, K., & Lewy, H. (1928). �ber die partiellen Differenzengleichungen der mathematischen Physik. Mathematische Annalen, 100(1), 32-74. doi:10.1007/bf0144883

Transformation of spin information into large electrical signals via carbon nanotubes

Spin electronics (spintronics) exploits the magnetic nature of the electron, and is commercially exploited in the spin valves of disc-drive read heads. There is currently widespread interest in using industrially relevant semiconductors in new types of spintronic devices based on the manipulation of spins injected into a semiconducting channel between a spin-polarized source and drain. However, the transformation of spin information into large electrical signals is limited by spin relaxation such that the magnetoresistive signals are below 1%. We overcome this long standing problem in spintronics by demonstrating large magnetoresistance effects of 61% at 5 K in devices where the non-magnetic channel is a multiwall carbon nanotube that spans a 1.5 micron gap between epitaxial electrodes of the highly spin polarized manganite La0.7Sr0.3MnO3. This improvement arises because the spin lifetime in nanotubes is long due the small spin-orbit coupling of carbon, because the high nanotube Fermi velocity permits the carrier dwell time to not significantly exceed this spin lifetime, because the manganite remains highly spin polarized up to the manganite-nanotube interface, and because the interfacial barrier is of an appropriate height. We support these latter statements regarding the interface using density functional theory calculations. The success of our experiments with such chemically and geometrically different materials should inspire adventure in materials selection for some future spintronicsComment: Content highly modified. New title, text, conclusions, figures and references. New author include

Predictors of Hospitalized Exacerbations and Mortality in Chronic Obstructive Pulmonary Disease

Background and Aim Exacerbations of chronic obstructive pulmonary disease (COPD) carry significant consequences for patients and are responsible for considerable health-care costs?particularly if hospitalization is required. Despite the importance of hospitalized exacerbations, relatively little is known about their determinants. This study aimed to analyze predictors of hospitalized exacerbations and mortality in COPD patients. Methods This was a retrospective population-based cohort study.We selected 900 patients with confirmed COPD aged 35 years by simple random sampling among all COPD patients in Cantabria (northern Spain) on December 31, 2011. We defined moderate exacerbations as events that led a care provider to prescribe antibiotics or corticosteroids and severe exacerbations as exacerbations requiring hospital admission.We observed exacerbation frequency over the previous year (2011) and following year (2012). We categorized patients according to COPD severity based on forced expiratory volume in 1 second (Global Initiative for Chronic Obstructive Lung Disease [GOLD] grades 1?4). We estimated the odds ratios (ORs) by logistic regression, adjusting for age, sex, smoking status, COPD severity, and frequent exacerbator phenotype the previous year. Results Of the patients, 16.4%had 1 severe exacerbations, varying from 9.3%in mild GOLD grade 1 to 44%in very severe COPD patients. A history of at least two prior severe exacerbations was positively associated with new severe exacerbations (adjusted OR, 6.73; 95%confidence interval [CI], 3.53?12.83) and mortality (adjusted OR, 7.63; 95%CI, 3.41?17.05). Older age and several comorbidities, such as heart failure and diabetes, were similarly associated. Conclusions Hospitalized exacerbations occurred with all grades of airflow limitation. A history of severe exacerbations was associated with new hospitalized exacerbations and mortality

In Vivo Dioxin Favors Interleukin-22 Production by Human CD4+ T Cells in an Aryl Hydrocarbon Receptor (AhR)-Dependent Manner

The transcription factor aryl hydrocarbon receptor (AhR) mediates the effects of a group of chemicals known as dioxins, ubiquitously present in our environment. However, it is poorly known how the in vivo exposure to these chemicals affects in humans the adaptive immune response. We therefore assessed the functional phenotype of T cells from an individual who developed a severe cutaneous and systemic syndrome after having been exposed to an extremely high dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).T cells of the TCDD-exposed individual were studied for their capacity to produce cytokines in response to polyclonal and superantigenic stimulation, and for the expression of chemokine receptors involved in skin homing. The supernatants from T cells of the exposed individual contained a substantially increased amount of interleukin (IL)-22 but not of IL-17A, interferon (IFN)-γ or IL-10 when compared to nine healthy controls. In vitro experiments confirmed a direct, AhR-dependent, enhancing effect of TCDD on IL-22 production by CD4+ T cells. The increased production of IL-22 was not dependent on AhR occupancy by residual TCDD molecules, as demonstrated in competition experiments with the specific AhR antagonist CH-223191. In contrast, it was due to an increased frequency of IL-22 single producing cells accompanied by an increased percentage of cells expressing the skin-homing chemokine receptors CCR6 and CCR4, identified through a multiparameter flow cytometry approach. Of interest, the frequency of CD4+CD25(hi)FoxP3+ T regulatory cells was similar in the TCDD-exposed and healthy individuals.This case strongly supports the contention that human exposure to persistent AhR ligands in vivo induce a long-lasting effect on the human adaptive immune system and specifically polarizes CD4+ T cells to produce IL-22 and not other T cell cytokines with no effect on T regulatory cells

Obstetric–Neonatal Care during Birth and Postpartum in Symptomatic and Asymptomatic Women Infected with SARS-CoV-2: A Retrospective Multicenter Study

Data Availability Statement: Data are available upon reasonable request. All necessary data are supplied and available in the manuscript; however, the corresponding author will provide the dataset upon request. All data relevant to the study are included in the article.Copyright © 2022 by the authors. This study analyses the obstetric–neonatal outcomes of women in labour with symptomatic and asymptomatic COVID-19. A retrospective, multicenter, observational study was carried out between 1 March 2020 and 28 February 2021 in eight public hospitals in the Valencian community (Spain). The chi-squared test compared the obstetric–neonatal outcomes and general care for symptomatic and asymptomatic women. In total, 11,883 births were assisted in participating centers, with 10.9 per 1000 maternities (n = 130) infected with SARS-CoV-2. The 20.8% were symptomatic and had more complications both upon admission (p = 0.042) and during puerperium (p = 0.042), as well as transfer to the intensive care unit (ICU). The percentage of admission to the Neonatal Intensive Care Unit (NICU) was greater among offspring of symptomatic women compared to infants born of asymptomatic women (p < 0.001). Compared with asymptomatic women, those with symptoms underwent less labour companionship (p = 0.028), less early skin-to-skin contact (p = 0.029) and greater mother–infant separation (p = 0.005). The overall maternal mortality rate was 0.8%. No vertical transmission was recorded. In conclusion, symptomatic infected women are at increased risk of lack of labour companionship, mother–infant separation, and admission to the ICU, as well as to have preterm births and for NICU admissions.FISABIO grant number UGP-20-24

Body weight and risk of soft-tissue sarcoma

The relation between body mass (BMI) and soft-tissue sarcoma (STS) risk was evaluated in a case–control study from Northern Italy based on 217 incident STS and 1297 hospital controls. The risk of STS rose with BMI, with multivariate odds ratios of 3.49 (95% confidence interval (CI) 1.06–11.55) among men and 3.26 (95% CI 1.27–8.35) among women with a BMI >30 kg m–2 compared to those with BMI ≤ 20 kg m–2. © 1999 Cancer Research Campaig

Procalcitonin levels in acute exacerbation of COPD admitted in ICU: a prospective cohort study

<p>Abstract</p> <p>Background</p> <p>Antibiotics are recommended for severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD) admitted to intensive care units (ICU). Serum procalcitonin (PCT) could be a useful tool for selecting patients with a lower probability of developing bacterial infection, but its measurement has not been investigated in this population.</p> <p>Methods</p> <p>We conducted a single center prospective cohort study in consecutive COPD patients admitted to the ICU for AECOPD between September 2005 and September 2006. Sputum samples or tracheal aspirates were tested for the presence of bacteria and viruses. PCT levels were measured at the time of admittance, six hours, and 24 hours using a sensitive immunoassay.</p> <p>Results</p> <p>Thirty nine AECOPD patients were included, 31 of which (79%) required a ventilator support at admission. The median [25%–75% interquartile range] PCT level, assessed in 35/39 patients, was: 0.096 μg/L [IQR, 0.065 to 0.178] at the time of admission, 0.113 μg/L [IQR, 0.074 to 0.548] at six hours, and 0.137 μg/L [IQR, 0.088 to 0.252] at 24 hours. The highest PCT (PCTmax) levels were less than 0.1 μg/L in 14/35 (40%) patients and more than 0.25 μg/L in 10/35 (29%) patients, suggesting low and high probability of bacterial infection, respectively. Five species of bacteria and nine species of viruses were detected in 12/39 (31%) patients. Among the four patients positive for <it>Pseudomonas aeruginosa</it>, one had a PCTmax less than 0.25 μg/L and three had a PCTmax less than 0.1 μg/L. The one patient positive for <it>Haemophilus influenzae </it>had a PCTmax more than 0.25 μg/L. The presence or absence of viruses did not influence PCT at time of admission (0.068 vs 0.098 μg/L respectively, <it>P </it>= 0.80).</p> <p>Conclusion</p> <p>The likelihood of bacterial infection is low among COPD patients admitted to ICU for AECOPD (40% with PCT < 0.1 μg/L) suggesting a possible inappropriate use of antibiotics. Further studies are necessary to assess the impact of a procalcitonin-based therapeutic strategy in critically ill COPD patients.</p

Cardiac tumours in children

Cardiac tumours are benign or malignant neoplasms arising primarily in the inner lining, muscle layer, or the surrounding pericardium of the heart. They can be primary or metastatic. Primary cardiac tumours are rare in paediatric practice with a prevalence of 0.0017 to 0.28 in autopsy series. In contrast, the incidence of cardiac tumours during foetal life has been reported to be approximately 0.14%. The vast majority of primary cardiac tumours in children are benign, whilst approximately 10% are malignant. Secondary malignant tumours are 10–20 times more prevalent than primary malignant tumours. Rhabdomyoma is the most common cardiac tumour during foetal life and childhood. It accounts for more than 60% of all primary cardiac tumours. The frequency and type of cardiac tumours in adults differ from those in children with 75% being benign and 25% being malignant. Myxomas are the most common primary tumours in adults constituting 40% of benign tumours. Sarcomas make up 75% of malignant cardiac masses. Echocardiography, Computing Tomography (CT) and Magnetic Resonance Imaging (MRI) of the heart are the main non-invasive diagnostic tools. Cardiac catheterisation is seldom necessary. Tumour biopsy with histological assessment remains the gold standard for confirmation of the diagnosis. Surgical resection of primary cardiac tumours should be considered to relieve symptoms and mechanical obstruction to blood flow. The outcome of surgical resection in symptomatic, non-myxomatous benign cardiac tumours is favourable. Patients with primary cardiac malignancies may benefit from palliative surgery but this approach should not be recommended for patients with metastatic cardiac tumours. Surgery, chemotherapy and radiotherapy may prolong survival. The prognosis for malignant primary cardiac tumours is generally extremely poor