Machine learning approximations to predict epigenetic age acceleration in stroke patients

Age acceleration (Age-A) is a useful tool that is able to predict a broad range of health outcomes. It is necessary to determine DNA methylation levels to estimate it, and it is known that Age-A is influenced by environmental, lifestyle, and vascular risk factors (VRF). The aim of this study is to estimate the contribution of these easily measurable factors to Age-A in patients with cerebrovascular disease (CVD), using different machine learning (ML) approximations, and try to find a more accessible model able to predict Age-A. We studied a CVD cohort of 952 patients with information about VRF, lifestyle habits, and target organ damage. We estimated Age-A using Hannum\u27s epigenetic clock, and trained six different models to predict Age-A: a conventional linear regression model, four ML models (elastic net regression (EN), K-Nearest neighbors, random forest, and support vector machine models), and one deep learning approximation (multilayer perceptron (MLP) model). The best-performing models were EN and MLP; although, the predictive capability was modest (

Orientaciones para la redición de cuentas en materia de cooperación internacional para el desarrollo para entidades locales de la Comunitat Valenciana

El documento consiste en una guia con orientaciones para favorecer la rendición de cuentas en materia de cooperación para el desarrollo para entidades sociales e instituciones en la Comunitat Valenciana

Orientaciones para la planificación de la cooperacion para el desarrollo en entidades locales de la Comunidad Valenciana

El documento consiste en una guia de orientación para las acciones de diseño y planificación de la cooperación para el desarrollo en el ámbito de la Comunitat Valencina

Over-speed turbine aerodynamics

The event of a HP shaft breakage will foster the rapid acceleration of the turbine. The current research has shown that an over-speed scenario (turbine rotating over design speed) in a contra-rotating turbine layout increases incidence angles in the IPT NGVs. The e↵ect of the over-speed in the IPT performance parameters has been evaluated by means of the capacity and efficiency based on the steady state assumption. The observed trend shows an incidence angle augmenting with the shaft rotational speed causing the capacity and efficiency to diminish for high levels of over-speed. The comparison of the steady and unsteady results reveals an interesting fact. At nominal conditions, the large distance separating the HPT rotor blades and IPT NGVs allows the flow to mix out before entering the IPT stage. Therefore, the transport of the unsteadiness downstream the turbine does not justify the added computational cost to be assumed in an unsteady simulation. The e↵ect of the axial displacement of the HPT rotor as a consequence of the over-speed event has been also assessed. The purpose of this part was to study the influence that the increase of massflow through the tip clearance exerted on the downstream component.Bru Revert, A. (2015). Over-speed turbine aerodynamics. Universitat Politècnica de València. http://hdl.handle.net/10251/62335Archivo delegad

Flow and Ingestion in a Turbine Disc Cavity under Rotationally-Dominated Conditions

An investigation of hot gas ingestion driven by the disc pumping effect in a chute seal was conducted at the Oxford Rotor Facility. Measurements of mean pressure, unsteady pressure and gas concentration have been logged and analysed under different operating conditions. The sensitivity of mean cavity pressure coefficient, frequency spectra of the unsteady pressures and sealing effectiveness to changing conditions of purge flow, annulus flow, rotor disc speed and seal clearance have been studied. The steady pressures revealed the development of two vortices in the cavity, induced by the sharp change in geometry of the stator wall. The increased shear at the interface between these two vortices strengthened the unsteady activity at this location. The addition of mainstream flow improved the sealing capability of the chute seal under certain operating conditions. The excitation of further frequencies when an axisymmetric annulus flow was introduced suggests a complex interaction between annulus and purge flows

Performance of a Turbine Rim Seal Subject to Rotationally-Driven and Pressure-Driven Ingestion

This experimental study considered the performance of a chute rim seal downstream of turbine inlet guide vanes (but without rotor blades). The experimental set up reproduced rotationally-driven ingestion without vanes and conditions of pressure-driven ingestion with vanes. The maximum rotor speed was 9000 rpm corresponding to a rotational Reynolds number of 3x106 with a flow coefficient of 0.48. Measurements of mean pressures in the annulus and the disc rim cavity as well as values of sealing effectiveness deduced from gas concentration data are presented. At high values of flow coefficient (low rotational speeds), the circumferential pressure variation generated by the vanes drove relatively high levels of ingestion into the disc rim cavity. For a given purge flow rate, increasing the disc rotation speed led to a reduction in ingestion shown by higher values of sealing effectiveness despite the presence of upstream vanes. At \u1d448\u1d44e\u1d465(Ω\u1d44f)⁄=0.48, the sealing effectiveness approached that associated with purely rotationally-driven ingestion. A map of sealing effectiveness against non-dimensional purge flow summarises the results and illustrates the combined rotational and pressure-driven effects on the ingestion mechanism. The results imply that flow coefficient is an important parameter in rim sealing and that rotational effects are important in many applications, especially turbines with low flow coefficient

Sealing Performance of a Turbine Rim Chute Seal Under Rotationally-Induced Ingestion

This study focuses on the sealing capability of a turbine rim seal subject to hot gas ingestion driven purely by the rotor disc pumping effect rather than that induced by mainstream features such as vane and rotor blade passing. The aim is to provide useful data for conditions in which rotation dominates, and to clarify the flow physics involved in rim sealing. Experimental measurements of sealing effectiveness for a chute seal are presented for the first time without and with an axial, axisymmetric mainstream flow external to the seal. The test matrix covers a range of rotational Reynolds number, Re , from 1.5x106 to 3x106, and nondimensional flow rate, C , from 0 to 4x104 with the mainstream flow (when present) scaled to match engine representative conditions of axial Reynolds number, Re . Results from steady pressure and gas concentration measurements within the rotor-stator disc cavity and the rim seal gap are presented and compared to published data for other seal designs. Sealing performance of the chute seal is somewhat similar to that of axial clearance seals with the same minimum clearance

Sealing Performance of a Turbine Rim Chute Seal Under Rotationally-Induced Ingestion

This study focuses on the sealing capability of a turbine rim seal subject to hot gas ingestion driven purely by the rotor disc pumping effect rather than that induced by mainstream features such as vane and rotor blade passing. The aim is to provide useful data for conditions in which rotation dominates, and to clarify the flow physics involved in rim sealing. Experimental measurements of sealing effectiveness for a chute seal are presented for the first time without and with an axial, axisymmetric mainstream flow external to the seal. The test matrix covers a range of rotational Reynolds number, Re , from 1.5x106 to 3x106, and nondimensional flow rate, C , from 0 to 4x104 with the mainstream flow (when present) scaled to match engine representative conditions of axial Reynolds number, Re . Results from steady pressure and gas concentration measurements within the rotor-stator disc cavity and the rim seal gap are presented and compared to published data for other seal designs. Sealing performance of the chute seal is somewhat similar to that of axial clearance seals with the same minimum clearance

Wall Modelled Large Eddy Simulations of Axial Turbine Rim Sealing

This paper presents WMLES simulations of a chute type turbine rim seal. Configurations with an axisymmetric annulus flow and with nozzle guide vanes fitted (but without rotor blades) are considered. The passive scalar concentration solution and WMLES are validated against available data in the literature for uniform convection and a rotor-stator cavity flow. The WMLES approach is shown to be effective, giving significant improvements over an eddy viscosity turbulence model, in prediction of rim seal effectiveness compared to research rig measurements. WMLES requires considerably less computational time than wall-resolved LES, and has the potential for extension to engine conditions. All WMLES solutions show rotating inertial waves in the chute seal. Good agreement between WMLES and measurements for sealing effectiveness in the configuration without vanes is found. For cases with vanes fitted the WMLES simulation shows less ingestion than the measurements, and possible reasons are discussed