Study of materials and manufacturing technologies for an antenna distribution network in Ka band

A study for selecting the technology and material manufacturing for the distribution network of a low profile antenna in Ka band in order to provide Internet connection in commercial aircrafts through satellite link. It is presented the general structure of the network focused in new printed technologies for high frequencies such as Substrate Integrated Waveguide or Ridge Gap Waveguide. Simulated results for different dielectric materials in terms of transmission losses are provided

Transporte de pescado con materiales de cambio de fase

Se analiza la pesca en España, planteando algunos de sus problemas como el derivado de la normativa de la Comunidad Europea, sobre la comercialización y el transporte del pescado y marisco con agua y hielo, y se proponen algunas soluciones, como es el empleo de mezclas eutécticas en bolsas o recipientes estancos. Figura 1

Los materiales de cambio de fase en las granjas y en los establos

Se analizan las condiciones climáticas que se requieren en las granjas de aves, en particular: temperatura, velocidades de aire, humedad, renovaciones de aire, en función del tipo de aves: pollos de engorde, ponedoras y para carne. Se revisan los tipos de granjas de aves más empleados y se establecen los sistemas de calefacción y climatización más usados en particular los de enfriamiento evaporativo. Se discuten los peligros más graves que tienen las granjas de aves debido a las temperaturas y las humedades.Se analizan los materiales de cambio de fase (PCM), en particular los que se consideran idóneos para su empleo en la climatización de granjas para aves. Por último se describen posibles soluciones para la climatización de granjas de aves empleando los PCM, concluyendo con un análisis de sus ventajas.Peer reviewe

Design proposal for ridge waveguide and comparison with other technologies in Ka to W bands

A design procedure of Ridge Gap Waveguide technology is proposed. The simulated results for Ka-band and above are compared with other technologies like Substrate Integrated Waveguide, microstrip or classical waveguide in terms of transmission losses

Local uniform stencil (LUST) boundary condition for arbitrary 3-D boundaries in parallel smoothed particle hydrodynamics (SPH) models

This paper presents the development of a new boundary treatment for free-surface hydrodynamics using the smoothed particle hydrodynamics (SPH) method accelerated with a graphics processing unit (GPU). The new solid boundary formulation uses a local uniform stencil (LUST) of fictitious particles that surround and move with each fluid particle and are only activated when they are located inside a boundary. This addresses the issues currently affecting boundary conditions in SPH, namely the accuracy, robustness and applicability while being amenable to easy parallelization such as on a GPU. In 3-D, the methodology uses triangles to represent the geometry with a ray tracing procedure to identify when the LUST particles are activated. A new correction is proposed to the popular density diffusion term treatment to correct for pressure errors at the boundary. The methodology is applicable to complex arbitrary geometries without the need of special treatments for corners and curvature is presented. The paper presents the results from 2-D and 3-D Poiseuille flows showing convergence rates typical for weakly compressible SPH. Still water in a complex 3-D geometry with a pyramid demonstrates the robustness of the technique with excellent agreement for the pressure distributions. The method is finally applied to the SPHERIC benchmark of a dry-bed dam-break impacting an obstacle showing satisfactory agreement and convergence for a violent flow.EPSRC, Reino Unido | Ref. EP/L014890/1Ministry of Education, Universities and Research, Italia | Ref. RBSI14R1GPXunta de Galicia | Ref. ED431C 2017/64Ministerio de Economía y Competividad | Ref. ENE2016-75074-C2-1-

Efficient response of an onshore Oscillating Water Column Wave Energy Converter using a one-phase SPH model coupled with a multiphysics library

In this paper the numerical modelling of an Oscillating Water Column (OWC) Wave Energy Converter (WEC) is studied using DualSPHysics, a software that applies the Smoothed Particle Hydrodynamics (SPH) method. SPH is a Lagrangian meshless method used in a growing range of applications within the field of Computational Fluid Dynamics (CFD). The power take-off (PTO) system of the OWC WEC is numerically modelled by adding a force on a plate floating on top of the free surface inside the OWC chamber. That force is implemented in the multiphysics library Project Chrono, which avoids the need of simulating the air phase that is computationally expensive in the SPH methods. Validation is carried out with experimental data received from the Korea Research Institute of Ship and Ocean Engineering (KRISO) and Ocean Energy Systems (OES) of the International Energy Agency (IEA) Task 10. The numerical and experimental water surface elevation at the centre of the OWC WEC chamber and the airflow speed through the orifice are compared for different wave conditions and different PTO systems (different orifice diameters at the top part of the chamber of the OWC WEC). Results show that DualSPHysics is a valid tool to model an OWC WEC with and without PTO system, even though no air phase is included.Research Foundation - Flanders | Ref. 1SC5421NXunta de Galicia | Ref. ED431C 2021/44Agencia Estatal de Investigación | Ref. IJCI-2017-3259

Effectiveness of a multifactorial intervention in increasing adherence to the mediterranean diet among patients with diabetes mellitus type 2: a controlled and randomized study (EMID Study)

The Mediterranean diet (MD) is recognized as one of the healthiest dietary patterns and has benefits such as improving glycaemic control among patients with type 2 diabetes (T2DM). Our aim is to assess the effectiveness of a multifactorial intervention to improve adherence to theMD, diet quality and biomedical parameters. The EMID study is a randomized and controlled clinical trial with two parallel groups and a 12-month follow-up period. The study included 204 subjects between 25–70 years with T2DM. The participants were randomized into intervention group (IG) and control group (CG). Both groups received brief advice about healthy eating and physical activity. The IG participants additionally took part in a food workshop, five walks and received a smartphone application for three months. The population studied had a mean age of 60.6 years. At the 3-month follow-up visit, there were improvements in adherence to the MD and diet quality of 2.2 and 2.5 points, compared to the baseline visit, respectively, in favour of the IG. This tendency of the improvement was maintained, in favour of the IG, at the 12-month follow-up visit. In conclusion, the multifactorial intervention performed could improve adherence to the MD and diet quality among patients with T2DM.Regional Health Management through the 2016 grants to carry out research projects in biomedicine, health management and socio-health care (GRS 1276/B/16), the 2016 program for the professional development of nurses in their research activity (BOCYL-D-11022016-2) and the 2015 incentive program for nurses who have completed their residency (ORDER SAN / 360/2015). The study was also co-financed by the Carlos III Health Institute and the European Regional Development Fund (ERDF) (RD 16/0007/0003)

Regular wave seakeeping analysis of a planing hull by smoothed particle hydrodynamics: a comprehensive validation

In this work, the dynamics of a planing hull in regular head waves was investigated using the Smoothed Particle Hydrodynamics (SPH) meshfree method. The simulation of the interaction of such vessels with wave trains features several challenging characteristics, from the complex physical interaction, due to large dynamic responses, to the likewise heavy numerical workload. A novel numerical wave flume implemented within the SPH-based code DualSPHysics fulfills both demands, guaranteeing comparable accuracy with an established proprietary Computational Fluid Dynamics (CFD) solver without sharpening the computational load. The numerical wave flume uses ad hoc open-boundary conditions to reproduce the flow characteristics encountered by the hull during its motion, combining the current and waves while adjusting their properties with respect to the vessel’s experimental towing speed. It follows a relatively small three-dimensional domain, where the potentiality of the SPH method in modeling free-surface flows interacting with moving structures is unleashed. The results in different wave conditions show the feasibility of this novel approach, considering the overall good agreement with the experiments; hence, an interesting alternative procedure to simulate the seakeeping test in several marine conditions with bearable effort and satisfying accuracy is established.Ministerio de Ciencia e Innovación | Ref. PID2020-113245RBI00Xunta de Galicia | Ref. ED431C 2021/44Ministerio de Ciencia e Innovación | Ref. TED2021-129479AI00Xunta de Galicia | Ref. ED481A-2021/337Ministerio de Ciencia e Innovación | Ref. RYC2020-030197-

A DEM approach for simulating flexible beam elements with the Project Chrono core module in DualSPHysics

This work presents a novel approach for simulating elastic beam elements in DualSPHysics leveraging functions made available by the coupling with the Project Chrono library. Such numerical frameworks, belonging to the Meshfree Particle Methods family, stand out for several features, like complex multiphase phenomena, moving boundaries, and high deformations which are handled with relative ease and reasonable numerical stability and reliability. Based on a co-rotating rigid element structure and lumped elasticity, a cogent mathematical formulation, relying on the Euler–Bernoulli beam theory for the structural discretization, is presented and applied to simulating two-dimensional flexible beams with the discrete elements method (DEM) formulation. Three test cases are presented to validate the smoothed particle hydrodynamics-based (SPH) structure model in both accuracy and stability, starting from an equilibrium test, to the dynamic response, and closing with a fluid–structure interaction simulation. This work proves that the developed theory can be used within a Lagrangian framework, using the features provided by a DEM solver, overtaking the initial limitations, and hence applying the results of static theories to complex dynamic problems.Xunta de Galicia | Ref. ED431C 2021/44Xunta de Galicia | Ref. ED481A-2021/337Ministerio de Ciencia, Innovación y Universidades | Ref. IJCI-2017-32592Agencia Estatal de Investigación | Ref. PID2020-113245RB-I0

GPUs, a new tool of acceleration in CFD: efficiency and reliability on smoothed particle hydrodynamics methods

Smoothed Particle Hydrodynamics (SPH) is a numerical method commonly used in Computational Fluid Dynamics (CFD) to simulate complex free-surface flows. Simulations with this mesh-free particle method far exceed the capacity of a single processor. In this paper, as part of a dual-functioning code for either central processing units (CPUs) or Graphics Processor Units (GPUs), a parallelisation using GPUs is presented. The GPU parallelisation technique uses the Compute Unified Device Architecture (CUDA) of nVidia devices. Simulations with more than one million particles on a single GPU card exhibit speedups of up to two orders of magnitude over using a single-core CPU. It is demonstrated that the code achieves different speedups with different CUDA-enabled GPUs. The numerical behaviour of the SPH code is validated with a standard benchmark test case of dam break flow impacting on an obstacle where good agreement with the experimental results is observed. Both the achieved speed-ups and the quantitative agreement with experiments suggest that CUDA-based GPU programming can be used in SPH methods with efficiency and reliability