Browsing by Keyword "Modelling"
Now showing 1 - 9 of 9
Results Per Page
Sort Options
Item Applying International Power Quality Standards for Current Harmonic Distortion to Wave Energy Converters and Verified Device Emulators(2019-09-24) Kelly, James; Aldaiturriaga, Endika; Ruiz-Minguela, Pablo; Tecnalia Research & InnovationThe push for carbon-free energy sources has helped encourage the development of the ocean renewable energy sector. As ocean renewable energy approaches commercial maturity, the industry must be able to prove it can provide clean electrical power of good quality for consumers. As part of the EU funded Open Sea Operating Experience to Reduce Wave Energy Cost (OPERA) project that is tasked with developing the wave energy sector, the International Electrotechnical Commission (IEC) developed electrical power quality standards for marine energy converters, which were applied to an oscillating water column (OWC). This was done both in the laboratory and in the real world. Precise electrical monitoring equipment was installed in the Mutriku Wave Power Plant in Spain and to an OWC emulator in the Lir National Ocean Test Facility at University College Cork in Ireland to monitor the electrical power of both. The electrical power generated was analysed for harmonic current distortion and the results were compared. The observations from sea trials and laboratory trials demonstrate that laboratory emulators can be used in early stage development to identify the harmonic characteristics of a wave energy converter.Item Direct route from ethanol to pure hydrogen through autothermal reforming in a membrane reactor: Experimental demonstration, reactor modelling and design: Experimental demonstration, reactor modelling and design(2018-01-15) Spallina, V.; Matturro, G.; Ruocco, C.; Meloni, E.; Palma, V.; Fernández-Gesalaga, E.; Melendez, J.; Pacheco Tanaka, David A.; Viviente Sole, J.L.; van Sint Annaland, M.; Gallucci, F.; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThis work reports the integration of thin (∼3–4 μm thick) Pd-based membranes for H2 separation in a fluidized bed catalytic reactor for ethanol auto-thermal reforming. The performance of a fluidized bed membrane reactor has been investigated from an experimental and numerical point of view. The demonstration of the technology has been carried out over 50 h under reactive conditions using 5 thin Pd-based alumina-supported membranes and a 3 wt%Pt-10 wt%Ni catalyst deposited on a mixed CeO2/SiO2 support. The results have confirmed the feasibility of the concept, in particular the capacity to reach a hydrogen recovery factor up to 70%, while the operation at different fluidization regimes, oxygen-to-ethanol and steam-to-ethanol ratios, feed pressures and reactor temperatures have been studied. The most critical part of the system is the sealing of the membranes, where most of the gas leakage was detected. A fluidized bed membrane reactor model for ethanol reforming has been developed and validated with the obtained experimental results. The model has been subsequently used to design a small reactor unit for domestic use, showing that 0.45 m2 membrane area is needed to produce the amount of H2 required for a 5 kWe PEM fuel-cell based micro-CHP system.Item Laser Texturing and Dissimilar Material Joining(2017) Ukar, E.; Liébana, F.; Andrés, M.; Marcos, I.; Lamikiz, A.; COMPOSITE; COMPUTER_VISIONLaser texturing is a process used to remove material selectively. Metallic parts were processed in order to create a surface texture that enables metal-polymer joining. This kind of dissimilar joining is carried out combining a pressure fixture and heating using a direct diode laser source. In order to reach a good result, it is critical to texture the surface with correct parameters to generate surface features that maximizes the contact between materials and heating enough the materials to soften the polymer but without melting and degrading the material, so, a temperature control system is necessary to get best results. In this work, the texturing capabilities of conventional CW laser source were explored and numerical model was developed in order to simulate and control the process temperature in the joining interface.Item Microstructural Evolution as a Function of Increasing Aluminum Content in Novel Lightweight Cast Irons(2021-10-18) Obregon, Alejandro; Sanchez, Jon Mikel; Eguizabal, David; Garcia, Jose Carlos; Arruebarrena, Gurutze; Hurtado, Iñaki; Quintana, Ion; Rodriguez, Patxi; PROMETAL; CIRMETALIn the context of the development of new lightweight materials, Al-alloyed cast irons have a great potential for reducing the weight of the different part of the vehicles in the transport industry. The correlation of the amount of Al and its effect in the microstructure of cast irons is not completely well established as it is affected by many factors such as chemical composition, cooling rate, etc. In this work, four novel lightweight cast irons were developed with different amounts of Al (from 0 wt. % to 15 wt. %). The alloys were manufactured by an easily scalable and affordable gravity casting process in an induction furnace, and casted in a resin-bonded sand mold. The microstructural evolution as a function of increasing Al content by different microstructural characterization techniques was studied. The hardness of the cast irons was measured by the Vickers indentation test and correlated with the previously characterized microstructures. In general, the microstructural evolution shows that the perlite content decrease with the increment of wt. % of Al. The opposite occurs with the ferrite content. In the case of graphite, a slight increment occurs with 2 wt. % of Al, but a great decrease occurs until 15 wt. % of Al. The addition of Al promotes the stabilization of ferrite in the studied alloys. The hardness obtained varied from 235 HV and 363 HV in function of the Al content. The addition of Al increases the hardness of the studied cast irons, but not gradually. The alloy with the highest hardness is the alloy containing 7 wt. % Al, which is correlated with the formation of kappa-carbides and finer perlite.Item Modelling of Light Mg and Al Based Alloys as “in situ” Composites(SPRINGER INT PUBLISHING AG, GEWERBESTRASSE 11, CHAM, CH-6330, SWITZERLAND, 2017-10-26) Parashkevova, Ludmila; Egizabal, Pedro; Todorov, Michail; Georgiev, Ivan; Georgiev, Krassimir; Georgiev, Ivan; Tecnalia Research & InnovationThe present paper is aimed to further elucidate the microstructure properties relationship of light alloys containing additional hard particles. The materials studded are magnesium alloys from the system AZ (Mg–Al–Mn–Zn) and mechanically alloyed aluminum reinforced with carbide and oxide particles. Strengthening and hardening phenomena in Metal Matrix Multiphase heterogeneous Materials (MMMM) are considered in this study from the view point of mechanics of nano- and micro-composites. A semi-analytical approach is adopted taking into account the manufacturing processing and microstructure features. Multilevel homogenization procedure is performed, accounting for size effects. In the model applied the metal matrix is considered as an elastic–plastic micropolar media and the hard phases (precipitations Mg17Al12, TiC, Al4C3, Al2O3) are treated as conventional elastic Cauchy materials. Experimentally observed dependence of the characteristic matrix length on the volume fraction of the hardening phases is modeled and numerically simulated in the case of ball-milled Al alloyed with Al4C3 and Al2O3. For AZ alloys the impact of intermetallic phase Mg17Al12 is discussed in the frame of presented composite model and the strengthening effect of the addition of small amount of TiC is estimated.Item Modelling the Component-based Architecture and Safety Contracts of ArmAssist in Papyrus for Robotics(Institute of Electrical and Electronics Engineers Inc., 2021-06) Martinez, Jabier; Ruiz, Alejandra; Garzo, Ainara; Keller, Thierry; Radermacher, Ansgar; Tonetta, Stefano; Tecnalia Research & Innovation; SWT; Quantum; Medical TechnologiesHealthcare robots are increasingly being used and the way they are engineered they still have several challenges regarding reference models and validation. In this experience report we focus on the ArmAssist robotic system and how it can be modelled including safety considerations for validation in early design phases. ArmAssist is an upper-limb robotic system for stroke rehabilitation based on serious games. The open-source tool Papyrus for Robotics was used for modelling the robotic system in close collaboration with neurorehabilitation domain experts. Papyrus for Robotics includes new functionalities that we contributed for contract-based design at component and system level, allowing to make explicit and validate the safety considerations using formal languages. In our case, the assertions are expressed in OCL and Othello. We present the resulting model and a discussion from domain experts.Item Modelling the optimum hot workability of TiB reinforced Ti-6Al-4 V alloy by stability maps(2016-02-17) García de Cortázar, Maider; Peñalba, Felix; Silveira, Elena; Gómez-Mitxelena, Xabier; Carsí, Manuel; Ruano, Oscar A.; Tecnalia Research & Innovation; CIRMETAL; Caracterización y Validación. Materiales; EXTREMATHot workability of Ti-6%Al-4%V and two whisker discontinuously reinforced materials, Ti-6%Al-4%V/1.2%TiB and Ti-6%Al-4%V/8.9%TiB, have been investigated. Hot uniaxial compression tests were carried out using a computer controlled thermomechanical simulator Gleeble machine at temperatures in the range 850 °C to 950 °C and strain rates ranging from 1 to 50 s−1. The microstructures and the compression test results were compared among the three materials. The Ti-6%Al-4%V/8.9%TiB material presented extensive cracking after deformation. In contrast, the Ti-6%Al-4%V/1.2%TiB material showed an interesting compromise between flow stress and workability. The parameters of the Garofalo equation were calculated for the three materials revealing apparent activation energies that increased with increasing TiB content. The modelling is carried out by stability maps that gives the temperature at a given strain rate to obtain optimal workability and the stresses that has to bear the equipment. Taken 5 s−1 as a reference strain rate, the temperature required to obtain a quality product increased from about 1143 K (870 °C) for the Ti-6-4 alloy without TiB to 1228 K (955 °C) for the 1.2%TiB and to 1283 K (1010 °C) for the 8.9%TiB material. Therefore, the production of parts of the TiB composites should be conducted at a higher forming temperature to avoid the presence of cracksItem OES Task 10 WEC heaving sphere performance modelling verification(CRC Press, 2018-09-12) Nielsen, K.; Wendt, F.; Yu, Y.-H.; Ruehl, K.; Touzon, Imanol; et al.OES Task 10 Modelling, Verification and Validation of Wave Energy Converters (WECs) is a task under the IEA Technology Collaboration Program for Ocean Energy Systems (OES). The long-term goals are to assess the accuracy of, and establish confidence in, the use of numerical WEC models, to determine a range of validity of existing computational modelling tools, to identify uncertainty related to simulation meth-odologies and finally to define future research. To some extent, this project builds on the experience from a similar effort carried out to verify modelling of wind turbines as part of the IEA Wind Task 30 on wind OC3-OC5.Item Self-healing Multi-Cloud Application Modelling(ACM Digital Library, 2017-08-29) Rios, Erkuden; Iturbe, Eider; Palacios, Maria Carmen; CIBERSEC&DLTCloud computing market forecasts and technology trends confirm that Cloud is an IT disrupting phenomena and that the number of companies with multi-cloud strategy is continuously growing. Cost optimization and increased competitiveness of companies that exploit multi-cloud will only be possible when they are able to leverage multiple cloud offerings, while mastering both the complexity of multiple cloud provider management and the protection against the higher exposure to attacks that multi-cloud brings. This paper presents the MUSA Security modelling language for multi-cloud applications which is based on the Cloud Application Modelling and Execution Language (CAMEL) to overcome the lack of expressiveness of state-of-the-art modelling languages towards easing: a) the automation of distributed deployment, b) the computation of composite Service Level Agreements (SLAs) that include security and privacy aspects, and c) the risk analysis and service match-making taking into account not only functionality and business aspects of the cloud services, but also security aspects. The paper includes the description of the MUSA Modeller as the Web tool supporting the modelling with the MUSA modelling language. The paper introduces also the MUSA SecDevOps framework in which the MUSA Modeller is integrated and with which the MUSA Modeller will be validated.