CFD-Aspen Plus interconnection method. Improving thermodynamic modelling in computational fluid dynamic simulations

Producción CientíficaThermodynamic modelling in CFD is basically limited to the models available in the simulators. The method presented in this paper connects CFD simulators with Aspen Plus which instantaneously calculates and returns the value of any physical property required. Therefore, all the thermodynamic models and compounds available in Aspen Plus can be implemented in CFD simulations. The connection, created via Matlab and Excel-VBA, has been validated solving two identical CFD simulations first selecting a thermodynamic model available in the simulator and then connecting the simulator with Aspen Plus and selecting the same model. The maximum absolute average deviation between the density and viscosity values obtained in both simulations, for the two case studies analyzed, is lower than 0.7% which demonstrates the proper interconnection. The accuracy of the results obtained modeling multicomponent mixtures and supercritical fluids proves the applicability of the method to any scenarios2018-12-31Ministerio de Economía, Industria y Competitividad - FEDER (Proyects CTQ2013-44143-R and CTQ2016-79777-R

Ultrafast heating by high efficient biomass direct mixing with supercritical water

Producción CientíficaThis work analyzes the influence of the mixer configuration on the mixing efficiency in the process of biomass ultrafast hydrolysis by supercritical water. The results of the CFD simulations of a horizontal tee, a vertical tee and a mixing cross, selected as the optimum mixing configurations, together with the experimental results obtained in our hydrolysis plant, are the base to determine the configuration which provides the best mixing performance. Although slightly higher conversions are obtained in those experiments performed with a horizontal tee, the small differences between the results demand a theoretical analysis. Therefore, according to the CFD simulation results, since the mixing cross provides the best flow distribution and temperature homogenization at the outlet of the mixers and because of the great similarity between the residence time distribution curves of the mixers, the mixing cross is selected as the optimum geometry to perform the mixing.Ministerio de Economía, Industria y Competitividad - FEDER (Projects CTQ2013-44143-R and CTQ2016-79777-R

El Cuerpo Humano desde la Perspectiva Japonesa

Un estudio centrado en el cuerpo humano y la cultura japonesa, en el que se desarrollan conceptos de la cultura mencionada a través de partes del cuerpo, de gestos y de comportamientos. Se analizan las implicaciones culturales de filosofías como el código samurái conocido como Bushido, o de prácticas como el suicidio ritual denominado seppuku. Un conjunto de fuentes en cuanto a anatomía, filosofía, medicina tradicional, psicoanálisis y antropología, entre otras, nos permitirán conocer más sobre la cultura japonesa, el cuerpo humano y los significados y conceptos implicados en ambos, así como las diferencias y similitudes existentes entre la cultura japonesa y la cultura Occidental. Para ello, tanto autores occidentales (Ruth Benedict, Andrew Rankin) como autores japoneses (Michitaro Tada, Inazō Nitobe) serán esenciales, aportando puntos de vista diferentes que darán lugar a una mayor diversidad en cuanto a perspectivas se refiere.Universidad de Sevilla. Grado en Estudios de Asia Orienta

Optimización de piezoeléctricos comerciales para su uso en sistemas de Energy Harvesting = Piezoelectric business optimization for use in energy systems harvesting

En este trabajo se caracterizan electromecánicamente materiales piezoeléctricos comerciales individuales y en diferentes configuraciones para su potencial uso en dispositivos detransformación de energía mecánica en eléctrica, con el objetivo de almacenarla y usarla en la alimentación de sistemas electrónicos de bajo consumo. Se plantean modelos optimizados de almacenamiento de dicha energía, teniendo en cuenta 2 posibilidades: captación de energía a partir de vibraciones continuas, incluso de baja intensidad, o captación de energía a partir de impactos. Se estudian diferentes configuraciones y se analiza la viabilidad de los modelos presentados mediante sistemas de vibración de frecuencia controlada y un banco de pruebas de simulación de paso de vehículos, dise˜nado y patentado por el grupo POEMMA R&D. Se enumeran aplicaciones cotidianas en las que pueden usarse los dispositivos en las configuraciones descritas. ABSTRACT. In this work, commercial piezoelectric materials are electromechanically characterized, indifferent configurations for potential use in harvesting devices of mechanical energy, inorder to store and use in the feeding of low power electronic systems. Optimization models considering two different types of mechanical energy are proposed:one for capture energy from continuous vibration, even low intensity and other for capture energy from impacts.Different configurations are discussed, and the feasibility of the models presented is analyzed by frequency vibration systems controlled and a test simulation of passing vehicles, designed and patented by POEMMA R&D group. Everyday applications in which devices in the configurations described may be used are listed

Redefining conventional biomass hydrolysis models by including mass transfer effects. Kinetic model of cellulose hydrolysis in supercritical water

Producción CientíficaConventional kinetic models of cellulose hydrolysis in supercritical water do not accurately represent the operation with concentrated suspensions since they neglect the mass transfer effects. This work proposes a kinetic model which is able to reproduce cellulose hydrolysis at high concentrations providing the opt imum reaction conditions to obtain nanocellulose particles and oligomers of controlled size. The basic idea of the model, which is applicable to other lignocellulosic materials, is that the hydrolysis of the cellulose particles generates an oligosaccharides layer which creates a mass transfer resistance. Therefore, it considers both the diffusion of the water molecules from the bulk phase to the surfaces of the cellulose particles and the superficial hydrolysis kinetics. Experimental points were obtained working with two different cellulose types (Dp=75 μm and Dp=50 μm) at 390 °C and 25 MPa, residence times between 50 ms and 250 ms and initial cellulose suspension concentration from 3% to 7% w/w (1% to 2.3% w/w at the inlet of the reactor). The average deviation between the experimental points and the theoretical values is lower than 10% proving the applicability of the kinetic model. The experimental and theoretical results demonstrated that increasing the total number of cellulose particles, either increasing the initial concentration or decreasing the average particle diameter, reduces the hydrolysis rate

Understanding biomass fractionation in subcritical & supercritical water

Producción CientíficaBiomass fractionation into its individual building blocks poses a major challenge to the biorefinery concept. The recalcitrance of the lignocellulose matrix and the high crystallinity of cellulose make typical feed stocks difficult to separate into their components. Hydrothermal processing fractionates biomass by its hydrolysis. However, a deep knowledge of hydrolysis principles is required since an inappropriate selection of the operating parameters such as an excessive temperature and a long residence times causes dramatic selectivity losses. This review is divided in four main sections which present the fundamentals of lignocellulosic biomass fractionation in hemicelluloses, cellulose and lignin. As the biomass structure plays an important role, a section to study the extraction of the linked phenols that joint lignin and hemicelluloses is included.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA040U16)Ministerio de Economía, Industria y Competitividad - FEDER (Proyect CTQ2013-44143-R)Ministerio de Economía, Industria y Competitividad - FEDER (Proyect CTQ2016-79777-R

Diabetes-specific enteral nutrition formula in hyperglycemic, mechanically ventilated, critically ill patients: a prospective, open-label, blind-randomized, multicenter study

Introduction: Although standard enteral nutrition is universally accepted, the use of disease-specific formulas for hyperglycemic patients is still controversial. This study examines whether a high-protein diabetes-specific formula reduces insulin needs, improves glycemic control and reduces ICU-acquired infection in critically ill, hyperglycemic patients on mechanical ventilation (MV). Methods: This was a prospective, open-label, randomized (web-based, blinded) study conducted at nine Spanish ICUs. The patient groups established according to the high-protein formula received were: group A, newgeneration diabetes-specific formula; group B, standard control formula; group C, control diabetes-specific formula. Inclusion criteria were: expected enteral nutrition >= 5 days, MV, baseline glucose > 126 mg/dL on admission or > 200 mg/dL in the first 48 h. Exclusion criteria were: APACHE II = 40 kg/m(2). The targeted glucose level was 110-150 mg/dL. Glycemic variability was calculated as the standard deviation, glycemic lability index and coefficient of variation. Acquired infections were recorded using published consensus criteria for critically ill patients. Data analysis was on an intention-to-treat basis. Results: Over a 2-year period, 157 patients were consecutively enrolled (A 52, B 53 and C 52). Compared with the standard control formula, the new formula gave rise to lower insulin requirement (19.1 +/- 13.1 vs. 23.7 +/- 40.1 IU/day, p < 0.05), plasma glucose (138.6 +/- 39.1 vs. 146.1 +/- 49.9 mg/dL, p < 0.01) and capillary blood glucose (146.1 +/- 45.8 vs. 155.3 +/- 63.6 mg/dL, p < 0.001). Compared with the control diabetes-specific formula, only capillary glucose levels were significantly reduced (146.1 +/- 45.8 vs. 150.1 +/- 41.9, p < 0.01). Both specific formulas reduced capillary glucose on ICU day 1 (p < 0.01), glucose variability in the first week (p < 0.05), and incidences of ventilator-associated tracheobronchitis (p < 0.01) or pneumonia (p < 0.05) compared with the standard formula. No effects of the nutrition formula were produced on hospital stay or mortality. Conclusions: In these high-risk ICU patients, both diabetes-specific formulas lowered insulin requirements, improved glycemic control and reduced the risk of acquired infections relative to the standard formula. Compared with the control-specific formula, the new-generation formula also improved capillary glycemia

Dielectric behaviour of Hf-doped CaCu3Ti4O12 ceramics obtained by conventional synthesis and reactive sintering

CaCu3(Ti4xHfx)O12 ceramics (JC = 0.04, 0.1 and 0.2) were prepared by conventional synthesis (CS) and through reactive sintering (RS), in which synthesis and sintering of the material take place in one single step. The microstructure and the dielectric properties of Hf-doped CCTO (CCTOHf) have been studied by XRD, FE-SEM, AFM, Raman and impedance spectroscopy (IS) in order to correlate the structure, microstructure and the electrical properties. Samples prepared by reactive sintering show slightly higher dielectric constant than those prepared by conventional synthesis in the same way than the pure CCTO. Dielectric constant and dielectric losses decrease slightly increasing Hf content. For CCTOHf ceramics with x> 0.04 for CS and x> 0.1 for RS, a secondary phase HfTi04 appears. As expected, the reactive sintering processing method allows a higher incorporation of Hf in the CCTO lattice than the conventional synthesis one

Multiscale entropy analysis of unattended oximetric recordings to assist in the screening of paediatric sleep apnoea at home

Producción CientíficaUntreated paediatric obstructive sleep apnoea syndrome (OSAS) can severely affect the development and quality of life of children. In-hospital polysomnography (PSG) is the gold standard for a definitive diagnosis though it is relatively unavailable and particularly intrusive. Nocturnal portable oximetry has emerged as a reliable technique for OSAS screening. Nevertheless, additional evidences are demanded. Our study is aimed at assessing the usefulness of multiscale entropy (MSE) to characterise oximetric recordings. We hypothesise that MSE could provide relevant information of blood oxygen saturation (SpO2) dynamics in the detection of childhood OSAS. In order to achieve this goal, a dataset composed of unattended SpO2 recordings from 50 children showing clinical suspicion of OSAS was analysed. SpO2 was parameterised by means of MSE and conventional oximetric indices. An optimum feature subset composed of five MSE-derived features and four conventional clinical indices were obtained using automated bidirectional stepwise feature selection. Logistic regression (LR) was used for classification. Our optimum LR model reached 83.5% accuracy (84.5% sensitivity and 83.0% specificity). Our results suggest that MSE provides relevant information from oximetry that is complementary to conventional approaches. Therefore, MSE may be useful to improve the diagnostic ability of unattended oximetry as a simplified screening test for childhood OSAS.Sociedad Española de Neumología y Cirugía Torácica (SEPAR) project 153/2015Junta de Castilla y León (Consejería de Educación) y el Fondo Europeo de Desarrollo Regional (FEDER), projects (RTC-2015-3446-1) y (TEC2014-53196-R)Ministerio de Economía y Competitividad (MINECO) y FEDER, y el proyecto POCTEP 0378_AD_EEGWA_2_P de la Comisión Europea. L.National Institutes of Health (NIH) grant 1R01HL130984-01Ministerio de Asuntos Económicos y Transformación Digital, grant IJCI-2014-2266

Medical nutrition therapy and clinical outcomes in critically ill adults: a European multinational, prospective observational cohort study (EuroPN)

BACKGROUND: Medical nutrition therapy may be associated with clinical outcomes in critically ill patients with prolonged intensive care unit (ICU) stay. We wanted to assess nutrition practices in European intensive care units (ICU) and their importance for clinical outcomes. METHODS: Prospective multinational cohort study in patients staying in ICU ≥ 5 days with outcome recorded until day 90. Macronutrient intake from enteral and parenteral nutrition and non-nutritional sources during the first 15 days after ICU admission was compared with targets recommended by ESPEN guidelines. We modeled associations between three categories of daily calorie and protein intake (low:  20 kcal/kg; > 1.2 g/kg) and the time-varying hazard rates of 90-day mortality or successful weaning from invasive mechanical ventilation (IMV). RESULTS: A total of 1172 patients with median [Q1;Q3] APACHE II score of 18.5 [13.0;26.0] were included, and 24% died within 90 days. Median length of ICU stay was 10.0 [7.0;16.0] days, and 74% of patients could be weaned from invasive mechanical ventilation. Patients reached on average 83% [59;107] and 65% [41;91] of ESPEN calorie and protein recommended targets, respectively. Whereas specific reasons for ICU admission (especially respiratory diseases requiring IMV) were associated with higher intakes (estimate 2.43 [95% CI: 1.60;3.25] for calorie intake, 0.14 [0.09;0.20] for protein intake), a lack of nutrition on the preceding day was associated with lower calorie and protein intakes (− 2.74 [− 3.28; − 2.21] and − 0.12 [− 0.15; − 0.09], respectively). Compared to a lower intake, a daily moderate intake was associated with higher probability of successful weaning (for calories: maximum HR 4.59 [95% CI: 1.5;14.09] on day 12; for protein: maximum HR 2.60 [1.09;6.23] on day 12), and with a lower hazard of death (for calories only: minimum HR 0.15, [0.05;0.39] on day 19). There was no evidence that a high calorie or protein intake was associated with further outcome improvements. CONCLUSIONS: Calorie intake was mainly provided according to the targets recommended by the active ESPEN guideline, but protein intake was lower. In patients staying in ICU ≥ 5 days, early moderate daily calorie and protein intakes were associated with improved clinical outcomes. Trial registration NCT04143503, registered on October 25, 2019. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13054-022-03997-z