Study of the optimal approach and detection phases for missions to small asteroids

Nowadays, small asteroids are catching the space community’s attention and interest. Instead of planning expensive missions to planets, missions to small asteroids (<100m) are of interest both because of their lower costs and scientific value. Small asteroids are extremely faint objects that are serendipitously discovered while they are extremely close to the Earth. After a period of only a few days, a newly discovered small object moves far enough from the Earth so that its brightness falls below the detectability threshold of current telescopes. If the length of time that the asteroid has been visible from Earth is not long enough, the uncertainty on its ephemerides may still be high. When a transfer is planned, the spacecraft is sent to a blind point since the asteroid cannot be seen from Earth. It becomes visible only the last days of the rendezvous trajectory. To ensure the meeting between the spacecraft and the object, only asteroids with very accurate ephemerides are targeted. The aim of the project is to gain an insight into optimal approach trajectories in order to ensure that a small object is detected or, failing a total certainty, maximizing the probability to detect it during the close approach. With this aim, the relative motion dynamics in the Hill coordinate frame will be studied and Matlab simulations will be performe

Adiciones y correcciones a la orquidoflora valenciana, VI

Se aportan datos sobre algunos táxones poco abundantes en la Comunidad Valenciana; a destacar la presencia de Barlia robertiana en Monòver, Himantoglossum hircinum en Bocairent, Orchis fragrans en el Parc Natural de la Serra de Mariola y Orchis italica en Castellonet de la Conquesta.It is shown some data about rare taxa at the Valencian Community, specially about Barlia robertiana in Monòver, Himantoglossum hircinum in Bocairent, Orchis fragrans in the Natural Park Serra de Mariola and Orchis italica in Castellonet de la Conquesta

Kinetic Control of Ultrafast Transient Liquid Assisted Growth of Solution-Derived YBa2Cu3O7-x Superconducting Films

Transient liquid assisted growth (TLAG) is an ultrafast non-equilibrium growth process mainly governed by kinetic parameters, which are only accessible through fast in situ characterizations. In situ synchrotron X-ray diffraction (XRD) analysis and in situ electrical resistivity measurements are used to derive kinetic diagrams of YBa2 Cu3 O7- x (YBCO) superconducting films prepared via TLAG and to reveal the unique peculiarities of the process. In particular, diagrams for the phase evolution and the YBCO growth rates have been built for the two TLAG routes. It is shown that TLAG transient liquids can be obtained upon the melting of two barium cuprate phases (and not just one), differentiated by their copper oxidation state. This knowledge serves as a guide to determine the processing conditions to reach high performance films at high growth rates. With proper control of these kinetic parameters, films with critical current densities of 2-2.6 MA cm-2 at 77 K and growth rates between 100-2000 nm s-1 are reached. These growth rates are 1.5-3 orders of magnitude higher than those of conventional methods.The authors acknowledge the European Research Council for the ULTRASUPERTAPE project (ERC-2014-ADG-669504), IMPACT project (ERC-2019-PoC-874964) and EU COST action for CA16218 (NANOCOHYBRI). The authors also acknowledge financial support from Spanish Ministry of Science and Innovation with PID2021-127297OB-C21 and PID2021-127297OB-C22, and from Spanish Ministry of Science, Innovation and Universities through the “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2015-0496 and CEX2019-000917-S), and from the Spanish Ministry of Economy and Competitiveness with the SUMATE project (RTI2018-095853-B-C21, RTI2018-095853-B-C22, co-financed by the European Regional Development Fund, MCIU/AEI/FEDER, UE). They also thank the Catalan Government (2017-SGR-1519) and the Catalan energy network XRE4S (2018 XARDI 00002) for their support. L.S., D.G., and A.K. acknowledge financial support from Spanish Ministry of Science, Innovation and Universities through the FPI grant PRE2019-090621, PRE2018-084537, and PRE2020-091817, respectively. L.So. and J.J. acknowledge financial support from Spanish Ministry for the FPU grants. S.R. thanks the Universitat de Girona for IFUdG grant and A.Q. thanks the Spanish Ministry of Science, Innovation and Universities (“Juan de la Cierva” postdoctoral fellowship [Grant no. IJC2018-035034-I]). The authors thank the Scientific Services at ICMAB and ICN2 Electron Microscopy Division. The authors acknowledge the use of instrumentation as well as the technical advice provided by the National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas” at University of Zaragoza. The authors also acknowledge SOLEIL Synchrotron for provision of synchrotron radiation facilities and are grateful for assistance while using the DiffAbs beamline.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

Use of Inkjet Printing to Obtain YBa2Cu3O7-x Thick Films by TLAG-CSD Process

En aquesta tesis es presenta una nova metodologia de deposició IJP per a la preparació de capes gruixudes de YBCO basades en solucions de precursors sense fluor (FF). L'avantatge es basa en l'alt rendiment dels precursors FF si s'utilitzen en combinació amb el creixement TLAG (creixement assistit per líquid transitori de capes CSD) amb creixements ultraràpids (> 1000 nm/s). L'ús de diferents additius, estratègies de deposició i evaporació, juntament amb l'ànalisi de les propietats reològiques de la solució i anàlisi termogravimètric per la identificació de les vies de descomposició dels precursors i de mecanismes de tensió, s'han realitzat mitjançant tècniques de caracterització avançada in-situ, per tal d'obtenir deposicions homogènies i capes pirolitzades de precursors sense defectes i amb gruixos elevats per aconseguir capes de ~1000 nm. de supercondcutor YBCO. Aquesta Tesi es distribueix en els següents capítols: • Capítol 2: Descripció dels materials i mètodes utilitzats al llarg de la tesi. • Capítol 3: Deposició d'impressió d'injecció de tinta amb aparell construit al laboratori. Descripció del procediment, anàlisi i discussió dels resultats. Ús de tècniques de caracterització in-situ amb la intenció d'aconseguir mostres gruixudes sense defectes utilitzant velocitats ràpides de deposició. • Capítol 4: Deposició d'impressió d'injecció de tinta mitjançant una metodologia discreta. Descripció del procediment i de les eines de caracterització utilitzades per a la correcta optimització del procés per assegurar una bona homogeneïtat de les capes gruixudes sense defectes. Descripció d'experimentació d'alt rendiment (HTE) i estudis combinatoris químics. • Capítol 5: Deposició d'impressió d'injecció de tinta mitjançant una metodologia amb una velocitat de deposició més ràpida i contínua per obtenir mostres gruixudes sense defectes, amb o sense escalfament del substrat, sobre monocristalls i substrats CCs. Discussió dels resultats obtinguts mitjançant tècniques de caracterització in-situ. Avaluació de la compatibilitat del mètode de creixement TLAG per a capes gruixudes a través de metodologies inkjet de impressió de tinta. La combinació de les tecnologies d'impressió d'injecció de tinta (Inkjet Printing) i el procés TLAG-CSD permet la fabricació de capes superconductores de YBCO de manera reproducible i d'alt rendiment, reduint així el cost del procés de fabricació, d'interès per al mercat.En esta tesis se presenta una nueva metodología de deposición IJP para la preparación de capas gruesas de YBCO basadas en soluciones de precursores sin flúor (FF). La ventaja se basa en el alto rendimiento de los precursores FF si se utilizan en combinación con el crecimiento TLAG (crecimiento asistido por líquido transitorio de capas CSD) con crecimientos ultrarrápidos (>1000 nm/s). El uso de diferentes aditivos, estrategias de deposición y evaporación, junto con el análisis de las propiedades reológicas de la solución y análisis termogravimétrico para la identificación de las vías de descomposición de los precursores y mecanismos de tensión, se han realizado mediante técnicas de caracterización avanzada in-situ, a fin de obtener deposiciones homogéneas y capas pirolizadas de precursores sin defectos y con grosores elevados para conseguir capas de ~1000 nm. de supercondcutor YBCO. Esta Tesis se distribuye en los siguientes capítulos: • Capítulo 2: Descripción de los materiales y métodos utilizados a lo largo de la tesis. • Capítulo 3: Deposición de impresión de inyección de tinta con aparato construido en el laboratorio. Descripción del procedimiento, análisis y discusión de resultados. Empleo de técnicas de caracterización in-situ con la intención de conseguir muestras gruesas sin defectos utilizando velocidades rápidas de deposición. • Capítulo 4: Deposición de impresión de inyección de tinta mediante una metodología discreta. Descripción del procedimiento y de las herramientas de caracterización utilizadas para la correcta optimización del proceso para asegurar una buena homogeneidad de las gruesas capas sin defectos. Descripción de experimentación de alto rendimiento (HTE) y estudios combinatorios químicos. • Capítulo 5: Deposición de impresión de inyección de tinta mediante una metodología con una velocidad de deposición más rápida y continua para obtener muestras gruesas sin defectos, con o sin calentamiento del sustrato, sobre monocristales y sustratos CCs. Discusión de los resultados obtenidos mediante técnicas de caracterización in situ. Evaluación de la compatibilidad del método de crecimiento TLAG para capas gruesas a través de metodologías inkjet de impresión de tinta. La combinación de las tecnologías de impresión de inyección de tinta (Inkjet Printing) y el proceso TLAG-CSD permite la fabricación de capas superconductoras de YBCO de forma reproducible y de alto rendimiento, reduciendo así el coste del proceso de fabricación, de interés para el mercado.A novel drop-on-demand IJP deposition methodology for the preparation of thick YBCO films based on Fluorine-free (FF) precursor solutions is presented. The advantage relies on the high throughput advantages of the FF precursors if used in combination with TLAG growth (Transient Liquid Assisted Growth of CSD layers) with ultrafast growth rates (>1000 nm/s). The use of different additives, deposition and evaporation strategies, together with the rheological properties of the solution, its thermogravimetric analysis, such as the decomposition pathways of the precursors and the identification of stress-relief mechanisms, have been analysed using advanced in-situ characterization techniques in order to obtain homogenous depositions and defect-free pyrolized films with high thicknesses (~1000 nm. YBCO films). The work of this Thesis is distributed and described in the following chapters: • Chapter 2: Description of Materials and Methods used throughout the thesis. • Chapter 3: Inkjet Printing deposition on the homemade apparatus. Description of the procedure, analysis and discussion of the results. Use of in-situ characterization techniques with the intention to achieve crack-free thick samples at fast rates of deposition. • Chapter 4: Inkjet Printing deposition using a discrete grid methodology. Description of the procedure and the characterization tools used for the correct optimization of the process to ensure good film homogeneity and crack-free thick layers. Description of high-throughput experimentation (HTE) and chemical combinatorial studies. • Chapter 5: Inkjet Printing deposition using a continuous grid methodology to obtain defect-free thick samples, with or without substrate heating, over single crystals and CCs substrates. Discussion of the results by using in-situ characterization techniques. Evaluation of the compatibility of the TLAG growth method for thick inkjet printed films. The combination of Inkjet Printing technologies and TLAG-CSD allows the fabrication of YBCO films with high throughput in a reproducible way, thus reducing the cost of a scalable industrial process of superconducting coated conductors of interest for the market

Study of the optimal approach and detection phases for missions to small asteroids

Nowadays, small asteroids are catching the space community’s attention and interest. Instead of planning expensive missions to planets, missions to small asteroids (<100m) are of interest both because of their lower costs and scientific value. Small asteroids are extremely faint objects that are serendipitously discovered while they are extremely close to the Earth. After a period of only a few days, a newly discovered small object moves far enough from the Earth so that its brightness falls below the detectability threshold of current telescopes. If the length of time that the asteroid has been visible from Earth is not long enough, the uncertainty on its ephemerides may still be high. When a transfer is planned, the spacecraft is sent to a blind point since the asteroid cannot be seen from Earth. It becomes visible only the last days of the rendezvous trajectory. To ensure the meeting between the spacecraft and the object, only asteroids with very accurate ephemerides are targeted. The aim of the project is to gain an insight into optimal approach trajectories in order to ensure that a small object is detected or, failing a total certainty, maximizing the probability to detect it during the close approach. With this aim, the relative motion dynamics in the Hill coordinate frame will be studied and Matlab simulations will be performe

Study of the optimal approach and detection phases for missions to small asteroids

Nowadays, small asteroids are catching the space community’s attention and interest. Instead of planning expensive missions to planets, missions to small asteroids (<100m) are of interest both because of their lower costs and scientific value. Small asteroids are extremely faint objects that are serendipitously discovered while they are extremely close to the Earth. After a period of only a few days, a newly discovered small object moves far enough from the Earth so that its brightness falls below the detectability threshold of current telescopes. If the length of time that the asteroid has been visible from Earth is not long enough, the uncertainty on its ephemerides may still be high. When a transfer is planned, the spacecraft is sent to a blind point since the asteroid cannot be seen from Earth. It becomes visible only the last days of the rendezvous trajectory. To ensure the meeting between the spacecraft and the object, only asteroids with very accurate ephemerides are targeted. The aim of the project is to gain an insight into optimal approach trajectories in order to ensure that a small object is detected or, failing a total certainty, maximizing the probability to detect it during the close approach. With this aim, the relative motion dynamics in the Hill coordinate frame will be studied and Matlab simulations will be performe

Optimization of the SD2 memory system

As far as is evidenced, man has sought the answers to his deepest questions by observing the sky. The findings and studies that have been made in this way have helped us know the planet where we live and our situation in the universe. From Greeks to now, through Galileo, Kepler or the Hubble telescope, look out was key to better know the Earth. The Rosseta Mission is the best example of this strategy. It is know that there are comets that have similar features with the Earth at its younger phase. So, the goal of the mission is to land on a comet surface and make a study about its composition and properties. In this way it could be increased the knowledge about how was the Earth, and furthermore, what were the conditions that allowed the emergence of life on it. The objective of this project is work on the optimization of one subsystem of this mission. It is known that the space missions have all their resources optimized in order to reach their goals (the power consumption, the heat, the memory, etc.). So, in that case, it is important to work on the optimization of the memory consumption of the SD2 subsystem