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In an iPWR (integral pressurized water reactor), the pressurizer is located at the top of the reactor vessel; this configuration requires the investigation of the mechanisms adopted for the homogenization of boron. In previous work, three representative experiments were conducted in an experimental installation made of stainless steel with a volumetric scale equal to 1:200, representing one-fourth of the pressurizer of an iPWR. The test facility layout was mounted so that the test section was fed with water or saline solutions with different concentrations, representing scenarios of boration or deboration. To determine the concentration at the inlet and outlet of the test section, samples have been collected every 10 min during the experiments representing some scenarios. The main goal in this work was to investigate how well mixing during boron dilution transients in the pressurizer of a small modular reactor can be modelled accurately by CFD (Computational Fluid Dynamics) codes. Two CFD codes were used, the commercial ANSYS CFX and the open source CFD code OpenFOAM. The use of open source software such as OpenFOAM offers a way to CFD gain acceptance in the licensing. The results of the comparison of simulations with an experiment at the test section were presented and showed a very good agreement. It was verified that deviations are less than 4%, both codes can be used to accurately represent this phenomenon. In order to improve future experiments, the dispersion of the solution inside the test section is studied with the aim to propose positions for sensors. A first simple configuration is proposed, but some further simulations will be done to find an optimum configuration.

Background: A lot of studies reported a link between air pollutants and negative health effects, which leads to an increased hospital admissions and outpatient visits. Several factors influence the exposure to intra-urban air pollution, such as traffic and climate. Aims-Objectives: To assess the influenceof air pollutants on total respiratory-related hospital admissions in a 1-year period in Valladolid, Spain. Methods: Hospital admissions in our Pneumology service throughout 2015 were retrospectively analyzed. Correlations between hospital admissions, air pollution data from the week prior to hospital admission(PM10, PM2.5, NO2 and O3 1-week lag), gender and diagnosis-related groups(GRDs) were analyzed by descriptive stadistic, linear correlation and regression, and stratified by trimester to adjust the seasonality of hospital admissions. Results: A total of 999 hospital admissions were analyzed(62.5% males;average age of 70±15.3 years old). The most frequent GRDs were pneumonia(44.8%) and COPD(7.6%). Mean of hospital admissions: daily 2.63 (SD 2.05), weekly 17.96 (SD 8.26) and weekly stratifying by seasons ranged between 27.6(SD 8.55) and 13.30(SD 5.08). The weekly averaged levels of pollutants were PM10 17.81(SD 7.07), PM2.5 11.53(SD 6.3), NO2 24.7(SD 8.3) and O3 48.45(SD 21.6). Weekly, the levels of PM10 and PM2.5 exceeded the limits recommended by WHO(36.5% and 42.3%, respectively). The pollutant levels were not significantly correlated with the number of admissions, neither after stratifying by seasons nor after adjusting for confounding factors. Conclusion: PM10, PM2.5, NO2 and O3 levels in the previous week were not linked with an increased number of respiratory-related hospital admissions in Valladolid.

The current hydrogen production is based on fossil fuels; they have a huge contribution to the atmosphere's pollution. Thermochemical water splitting cycles don't present this issue because the required process heat is obtained from nuclear energy and therefore, the environmental impact is smaller than using conventional fuels. Although, solar hydrogen production could be also used for practical applications because it's lower environmental impact. One of the promising approaches to produce large quantities of hydrogen in an efficient way using nuclear energy is the sulfur–iodine (S–I) thermochemical water splitting cycle. The nuclear source proposed in this paper is a pebble bed gas cooled transmutation facility. Pebble bed very high temperature advanced systems have great perspectives to assume the future nuclear energy. Softwares based on CPS (chemical process simulation) can be used to simulate the thermochemical water splitting sulfur-iodine cycle for hydrogen production. In this paper, a model for analyzing the sulfur-iodine process sensibility respect to the thermodynamics parameters: temperature, pressure and mass flow is developed. Efficiency is also calculated and the influence of different parameters on this value. The behavior of the proposed model for different values of initial reactant's flow, is analyzed.

Background. The development of home-based screening tests in sleep apnoea-hypopnoea syndrome (SAHS) diagnosis is essential to increase the accessibility to diagnostic facilities. Chronic obstructive pulmonary disease (COPD) is very prevalent among SAHS patients. However, almost all studies assessing home-based screening tests for SAHS excluded patients with COPD. Objectives. To assess the influence of suffering from COPD in the diagnostic performance of an at-home screening test for moderate-to-severe SAHS based on automated analysis of nocturnal oximetry by means of a multilayer perceptron neural network (MLP-NN). Methods. All patients showed moderate-to-high suspicion of suffering from SAHS. The population was divided into a training set (193) and two test sets (NO COPD: 110, COPD: 68). In-laboratory PSG was the gold standard. All patients carried out unsupervised nocturnal oximetry at home. Statistical, spectral and nonlinear features were computed and fed a regression MLP-NN trained to estimate the AHI. Results. The MLP-NN achieved similar concordance (intra-class correlation) between actual and estimated AHI in both NO COPD (0.73) and COPD (0.79) groups. The MLP-NN achieved high sensitivity values both in the NO COPD (97.5%, 80.9%) and in the COPD (86.5%, 84.6%) test sets for the cut-offs 15 and 30 events per hour, respectively. The MLP-NN reached lower specificity both in the NO COPD (24.1%, 70.2%) and in the COPD (37.5%, 69.0%) populations. Conclusions. Suffering from COPD does not affect the performance of a MLP-NN in the diagnosis of moderate-to-severe SAHS using unsupervised nocturnal oximetry at patient9s home.

Background. Paediatric obstructive sleep apnoea-hypopnoea syndrome (OSAHS) has emerged as a frequent and concerning medical condition in the past 2-3 decades. In-laboratory overnight polysomnography (PSG) is the gold standard diagnostic technique but is complex and relatively inaccessible. Objectives. Blood oxygen saturation (SpO 2 ) from nocturnal oximetry could provide essential information in order to simplify the diagnostic process. The goal of this study was to design and assess an automated classifier aimed at detecting OSAHS. Methods. The population under study was composed of 176 children referred to the Sleep Unit due to suspected OSAHS. All children underwent complete in-laboratory PSG as gold standard. An apnoea-hypopnoea index (AHI) greater than or equal to 5 e/h were considered OSAHS positive. The population was randomly divided into training set (60%) and test set (40%). SpO 2 recordings from PSG were processed offline. Three nonlinear measures were derived from nocturnal SpO 2 recordings and used to design a support vector machine (SVM) classifier. Conventional oxygen desaturation index of 3% (ODI3) was used for comparison purposes. Results. The SVM classifier reached 85.7% sensitivity, 81.0% specificity, 4.50 LR+, 0.18 LR-, and 82.9% accuracy in the test set. On the contrary, ODI3 achieved 89.3% sensitivity, 69.1% specificity, 2.89 LR+, 0.16 LR-, and 77.1% accuracy in the same test set. Conclusions. The proposed SVM classifier outperforms the conventional desaturation index ODI3. Therefore, SVMs and nonlinear measures could provide useful tools to assist in the diagnosis of paediatric OSAHS.

Resumen Introduccion La medida de tendencia central (MTC) es una tecnica de analisis no lineal que aplicada a diagramas de diferencias de segundo orden permiten cuantificar el grado de variabilidad de una serie de datos. En el presente estudio, se pretende cuantificar y caracterizar las modificaciones de la frecuencia cardiaca obtenidas por pulsioximetria en pacientes con sospecha clinica de sindrome de apnea hipopnea del sueno (SAHS) mediante la utilizacion de la MTC y valorar su utilidad diagnostica. Pacientes y metodos Se incluyen en el estudio 187 pacientes, realizandose un estudio polisomnografico y pulsioximetrico nocturno. Para la valoracion de la variabilidad de la frecuencia cardiaca, se utilizo la MTC aplicada a graficos de diferencias de segundo orden obtenidos del registro de la frecuencia cardiaca. Resultados Los pacientes con SAHS presentaron una mayor variabilidad de la frecuencia cardiaca que los pacientes sin SAHS (0,449 vs. 0,666, p Conclusiones Los pacientes con SAHS presentan durante la noche una mayor variabilidad de la frecuencia cardiaca, valorada mediante la aplicacion de la medida de tendencia central a diagramas de diferencias de segundo orden de la frecuencia cardiaca. Como metodo de despistaje, la MTC aplicada a la frecuencia cardiaca presentan una sensibilidad y especificidad moderada.

a b s t r a c t Introduction: The measurement of central tendency (MCT) is a non-linear analysis technique which applied to second order differences diagrams enables the degree of variability to be quantified in a data series. In the present study an attempt is made to quantify and characterise the changes in heart rate obtained by pulse oximetry in patients with a clinical suspicion of sleep apnoea/hypoapnoea syndrome (SAHS) using the MCT and to evaluate its diagnostic use. Patients and Methods: A total of 187 patients were included in the study, on whom a nocturnal polysomnographic and pulse oximetry study was performed. To evaluate the variability of the heart rate the MCT applied to graphs of second order differences obtained from the heart rate record. Result: Patients with SAHS had a higher heart rate variablity than patients without SAHS (0.449 vs 0.666, P