Tesis (Ingeniería Aeroespacial y Mecánica de Fluidos)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/11335

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Satellite maneuver detection with radar data: Leveraging improved orbital uncertainty characterization for reachability-based metrics
(2024-05-27) Montilla García, José Manuel; Galán Vioque, Jorge Francisco; Vázquez Valenzuela, Rafael; Universidad de Sevilla. Departamento de Matemática Aplicada II (ETSI); Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
La importancia estratégica de la Órbita Baja Terrestre (LEO) ha crecido significativamente con el aumento de despliegues de satélites. Esta región se ha vuelto crucial para la economía espacial, con la Agencia Espacial Europea estimando más de 8500 satélites activos en LEO, que representan solo una fracción del total de objetos en esta banda orbital. La última década ha visto un aumento exponencial en la población de satélites, principalmente debido al advenimiento de mega-constelaciones para Internet global y la reducción de los costes de lanzamiento. Esta tesis profundiza en las complejidades de la detección de maniobras en mitad de los desafíos presentados por la congestión orbital y la basura espacial en LEO. Algunos satélites no comunican la realización de maniobras, lo que hace que sus trayectorias sean impredecibles. La detección de maniobras es fundamental para mantener catálogos orbitales y prever posibles colisiones, necesitando pues de métodos de detección robustos y eficientes. Esta tesis presenta el desarrollo de nuevas métricas y algoritmos para la detección de maniobras en órbita baja terrestre. Se centra en un escenario donde solo se dispone de datos de una única estación de radar, con el objetivo final de crear algoritmos de detección de maniobras para el Radar de Vigilancia y Seguimiento Espacial Español. La estructura sigue la evolución cronológica de la investigación, cada capítulo revisando contribuciones específicas de las etapas del doctorado. Inicialmente, la detección de maniobras se aborda desde el punto de vista del análisis de accesibilidad, estudiando la viabilidad de una métrica de Distancia de Mahalanobis (MD) derivada de un attributable en el espacio de medidas, y su inclusión en un Filtro de Detección de Maniobras. Los métodos desarrollados se prueban en datos reales de satélites con éxito variable, mostrando dónde residen los aspectos críticos del problema. La correcta representación de la incertidumbre bajo largos intervalos de propagación se convierte en el foco de mejora en adelante. Se utilizan mezclas gaussianas para obtener una métrica más realista que tenga en cuenta la evolución no lineal de la distribución de probabilidad del estado orbital, inspirada en la literatura y denominada coste de asociación. Este coste sirve para definir una nueva métrica destinada a detectar la divergencia entre la predicción y el attributable del radar, la variación del coste, aumentando la sensibilidad para detectar mediciones de radar anómalas. Con el fin de aprovechar mejor el conjunto completo de mediciones de radar, se desarrolla más tarde una metodología de Determinación Inicial de Órbita para estimar el estado orbital. Esto se logra ajustando medidas de radar, con un propagador J2 propio, y mejorando su precisión mediante la inclusión de información predicha del plano orbital (método OPOD). Finalmente, OPOD se usa para una métrica de detección de maniobras de estado completo basada en la MD que usa un sistema de coordenadas curvilíneo ideal para esta finalidad, ya que conserva la distribución gaussiana del estado predicho mas tiempo, reduciendo los falsos positivos. En conclusión, esta tesis es una contribución destacada al entendimiento e implementación de la detección de maniobras en LEO. Propone métodos para aprovechar de manera confiable y eficiente la información proporcionada por estaciones de radar, con la esperanza de mejorar la capacidad de dichas operaciones para hacer frente al creciente flujo de satélites en nuestros cielos.
Caracterización de las royas del trigo en Andalucía y uso de sensores remotos para su detección temprana
(2024-01-17) Rodríguez Vázquez, Jaime Nolasco; Apolo Apolo, Orly Enrique; Martínez Moreno, Fernando Bienvenido; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Universidad de Sevilla. Departamento de Agronomía
Las royas son una enfermedad importante en el cultivo del trigo, generando pérdidas de producción y, por tanto, económicas, en el sector cerealista. Podemos distinguir principalmente tres especies que causan tres enfermedades diferentes: roya de la hoja (o parda), amarilla (o lineal) y del tallo (o negra). Hasta la temporada 2019-2020, la roya de la hoja estaba controlada, ya que los cultivares más sembrados en el sur de España tenían genes de resistencia contra ella, y los cultivares susceptibles estaban protegidos con fungicidas. Pero un problema surgió en la primavera de 2020, cuando todos los cultivares de trigo duro comenzaron a infectarse con una roya parecida a la de la hoja. La roya del tallo apenas está presente durante la temporada de cultivo regular, pero puede ser una enfermedad importante en el futuro. Se identificaron las principales razas como Clade IV-B y Clade IV-F, al igual que en la mayor parte de Europa y partes del norte de África. Para esta roya, las resistencias siempre son incompletas.
Contribución para la mejora de procesos en la agroindustria de la aceituna
(2023-12-22) López Gordillo, Miguel Calixto; Madueño Luna, Antonio; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Universidad de Sevilla. Departamento de Agronomía
Esta tesis se ha planteado como una contribución para la mejora de procesos en la agroindustria de la aceituna concretamente dos mejoras en la industria de aceituna de mesa y una en la industria del aceite. Siendo sus objetivos los siguientes: 1. Caracterización del proceso de cocido de la aceituna verde “estilo sevillano” mediante visión artificial. 2. Diferenciación entre aceites de oliva virgen extra (AOVEs) mediante impedancia eléctrica y redes neuronales. 3. Mejora en el funcionamiento de máquinas deshuesadoras, rellenadoras y rodajadoras (DRR) mediante el uso de visión artificial. La metodología seguida ha sido: Partiendo de datos tomados en varias agroindustrias de campañas anteriores (cocido (2017) y deshuesado (2018) y de los datos obtenidos del análisis de aceites comerciales de la campaña de 2022 se han planteado tres hitos: 1. El análisis del cocido de la aceituna de mesa estilo sevillano siguiendo el procedimiento descrito en la patente P201100462/WO2012146799 A1/PCT/ES2012/000104. 2. Clasificado de cuatro AOVEs (ampliado a 18 aceites monovarietales, y dos aceites de control uno de orujo y otro de girasol), mediante redes neuronales. 3. Una mejora en el funcionamiento de las máquinas DRR mediante técnicas de visión artificial que permite ver la correcta selección de calibres de las aceitunas que llegan a la máquina DRR así como la bondad en el ajuste mecánico de la misma a partir del conteo de aceitunas mal posicionadas cuando van a ser deshuesadas.
Experimental and theoretical study about drop impact on inclined surfaces and substrates with different roughness and wettability
(2023-07-13) Garcia Geijo, Paula; Gordillo Arias de Saavedra, Jose Manuel; Riboux, Guillaume Maurice; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
En esta tesis se abordan tres aspectos relacionados con el impacto de gotas sobre superficies lisas y rugosas, tanto hidrofílicas como hidrófobas. El estudio del impacto de gotas sobre sustratos sólidos puede clasificarse en: i) el análisis de la expansión, conocida como spreading, y posterior retracción (en caso de que la hubiere), y ii) en la determinación de la velocidad crítica a partir de la cual la gota se disgrega en otras más pequeñas (fenómeno denominado splashing). Así, tras una breve introducción de los fenómenos a analizar, el segundo capítulo de esta tesis se dedicará al estudio de la evolución temporal de la expansión de gotas de líquidos de baja viscosidad al impactar sobre superficies lisas e inclinadas, siendo este proceso totalmente semejante al impacto de una gota formando una trayectoria inclinada con respecto a un substrato sólido horizontal. En estas situaciones, el proceso de expansión desarrolla asimetrías que no habían sido cuantificadas hasta la fecha. El tercer y cuarto capítulos están relacionados entre sí. En ellos se realiza un análisis exhaustivo del proceso de splashing en superficies rugosas, tanto hidrofílicas como hidrófobas, y se logra construir un diagrama que permite determinar la velocidad de transición al splash a presión atmosférica en función de las propiedades materiales del líquido, del ángulo de contacto estático, así como de la rugosidad relativa de la superficie. Por tanto, en esta tesis se proporciona una descripción completa de la transición al splash sobre superficies genéricas que posee un claro interés tecnológico.
Development and assessment of AI models based on deep learning algorithms to determine agronomic traits in fruit tree orchards and field crops
(2022-11-23) Apolo Apolo, Orly Enrique; Pérez Ruiz, Manuel; Egea Cegarra, Gregorio; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
It’s been claimed by the scientific community that we will need fifty percent more food by 2050 for a world population of close to 10 billion, resulting in a global crisis which raises the question of whether the global food production system is prepared for these changes. To face these challenges, new higher yielding crop varieties with resistance or tolerance to a wide spectrum of environmental stresses (e.g., drought) are desirable. But at the same time, crop management practices in actual farming systems also need to be improved. Agricultural stakeholders consider that these new challenges can be addressed, at least partly, by the adoption of new technologies, especially those related with remote sensing and data management (e.g., big data and artificial intelligence). Advanced sensors and algorithms may provide accurate and more consistent predictions on plant status and quality than those provided by the human eye. Implementing autonomous techniques in production systems may provide accurate field data to breeders and growers that can potentially increase yield and quality through well-considered management choices. In this thesis, it was stablished as main objective the development and assessment of AI models based on deep learning algorithms to determine agronomic traits in fruit tree orchards and field crops that can provide support to breeders and growers to meet the abovementioned challenges. Three papers published in scientific journals (Q1) were included as the main part of the research. In Chapter 4, Faster R-CNN, a pre-trained model widely used for object detection (e.g., fruits), was trained over a custom dataset labeled to detect oranges in images acquired from UAV (Unmanned Aerial Vehicle) flights. The evaluation of the model in terms of accuracy showed an average standard error (SE) of 6.59 % between visual counting and the model’s fruit detection. The detected fruits were converted to a binary mask using color thresholding to perform fruit size estimations. The promising results obtained indicate that this size estimation method can be employed for size discrimination prior to harvest. Also, a model based on Long Short-term Memory (LSTM) was trained for yield estimation of individual trees and for orchard yield estimation. The actual and estimated yields per tree were compared, resulting in an approximate standard error of SE = 4.53 % and a standard deviation of SD = 0.97 kg. The actual orchard yield and the orchard yield estimated by the model and by a trained technician were compared. The error in the estimation made by the technician was SE = 13.74 %, while the model errors were SE = 7.22 % and SD = 4083.58 kg. In Chapter 5, a Region-Convolutional Neural Network was trained to detect and count the number of apple fruits on individual trees located on the orthomosaic built from RGB images taken from an UAV. The results obtained with the proposed approach were compared with the apple counts made in situ by an agrotechnician, and an R2 value of 0.86 was obtained (MAE: 10.35 and RMSE: 13.56). As only parts of the tree fruits were visible in the top-view images, linear regression was used to estimate the number of total apples on each tree. An R2 value of 0.80 (MAE: 128.56 and RMSE: 130.56) was achieved. With the number of fruits detected and tree position coordinates two shapefiles were generated using a Python script implemented in Google Colab. The point shapefile layer was used to display two yield maps: one with the number of fruits per tree and another with the total number of fruits per tree row. Finally, in Chapter 6, a novel model based on artificial intelligence algorithms and nadir-view red-green-blue (RGB) images acquired with a terrestrial High-Throughput Field Phenotyping Platform (HTFPP) is presented. The model mixes numerical data collected in a wheat breeding field and visual features extracted from the images to make rapid and accurate leaf area index (LAI) estimations. Model-based LAI estimations were validated against LAI measurements determined non-destructively using an allometric relationship obtained in this study. The model performance was also compared with LAI estimates obtained by other classical indirect method based on bottom up digital hemispheric photographs (DHPs) which performs LAI estimations based on gap fraction theory. Model-based LAI estimations were highly correlated with ground-truth LAI. The model performance was slightly better than that of the hemispherical image based method, which tended to underestimate LAI. The results obtained in the three crops showed great potential in terms of estimating yield, fruit size and LAI. These results allow us to affirm that fruit growers and plant breeders can benefit from the implementation of these technologies in their commercial and experimental fields to maximize outputs via optimized orchard and breeding cycle management.
Fluid Mechanics for Biomedical Applications: Weakly Viscoelastic Electrospray, Flow Focusing and Collapsible Channel Models
(2022-09-09) Blanco Trejo, Sergio; Gañán-Calvo, Alfonso M.; Herrada Gutiérrez, Miguel Ángel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Three different research topics are discussed in this thesis: i) weakly-viscoelastic electrospray, ii) the emergence of whipping effect on the Flow Focusing technique, and iii) fluid-structure interaction (FSI) phenomena implementing a 2D collapsible channel model. i) A systematic, theoretical comparison of a Newtonian fluid, and a non-Newtonian one modelled using an Oldroyd-B model was performed, resulting in a better understanding of how the properties of this type of material influence aspects such as meniscus shrinking, the agreement with a 1D-slenderness model, or the minimum flow rate value defining the boundary between electrospray and electrospinning. ii) In order to use Flow Focusing for some applications (e.g. XFEL), chaotic oscillations on the jet, known as whipping, must be avoided. A stability map for axisymmetric and lateral perturbation modes was obtained and compared to previous experimental data, examining the effect of different nozzle geometries on the emergence of the whipping effect and jetting-to-dripping configuration physical boundary. iii) In the last paper, the implemented model overcame some limitations presented in other 2D collapsible channel models, leading to analysis using a non-negligible membrane thickness and large deformations on the flexible wall segment. The multiplicity of solutions and their folding points, and the quantification of the effect of physical parameters such as wall thickness and inertia values on the emergence of self-excited oscillations were investigated.
Technical and Environmental Feasibility of Recycled Plastic Fibres From Food Packaging Wastes as Reinforcement in Concrete
(2022-05-13) Vaccaro, Pietro Antonio; Ayuso Muñoz, Jesús; López Uceda, Antonio; Pérez Galvín, Adela; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
The growing and current concern for the enormous quantities of plastic waste produced each year, and the now inevitable daily use of plastic, has attracted the attention of more and more researchers for many years. Plastic waste can follow different paths in order to be disposed or be recycled or transformed into energy. The plastic packaging sector occupies the first place in Europe with regard to the use of plastic, and for this reason, most of the studied have focused on it in order to find solutions at the end of life of this material. Within plastic packaging, a large part of the market is made up of food plastic packaging. Its countless advantages have been developed in recent years thanks to new technologies and new material products. Among these, it can be found that the films used in food plastic packaging can be monolayer, made with a single material, or multilayer, which instead consist of two or more layers of different materials for each layer. The latter offer numerous advantages over the former because multiple functions and requirements are met at the same time. Simultaneously, however, numerous problems appears when they become waste difficult for managing because their recycling is difficult, due to it is made up of materials with different characteristics. The main objective of this doctoral thesis is to help find a new end-of-life to multilayer food plastic packaging waste and, at the same time, to deal with the use of innovative materials in the engineering and construction sector. This research was addressed on two points: from a technical nature, aiming at ascertaining whether the new material tested, that is the concrete reinforced with recycled plastic fibres (RPF) obtained from multilayer films of industrial waste from food plastic packaging, had the same physical characteristics and mechanical performance compared to ordinary concrete; and from an environmental nature, aiming at assessing the impact on environment that this new material could have based on leaching tests. The research was divided into the following phases: 1. A first theoretical phase of bibliographic and regulatory investigation on the subject of the doctoral thesis, during which a bibliographic compilation and revision of the updated literature on the topic was carried out; 2. A second phase, which was experimental, from a feasibility and technical perspective, that developed through the acquisition of plastic waste from a Spanish company operating in the packaging sector, with which the macro plastic fibres used were obtained and prepared, and then added to the mixture to produce the concrete specimens necessary to be subjected to physical and mechanical tests. The specimens produced were cubic, cylindrical, and prismatic with a fibre content of 2 kg/m3, 4 kg/m3 and 6 kg/m3. Two types of control specimens were also made: a control specimen of concrete without reinforcement, and fibre-reinforced concrete made with a commercial polypropylene fibre with a dosage of 2 kg per m3 of concrete. From the results of the compression and bending tests, the respective resistance values at 7 and 28 days, the modulus of elasticity and the toughness of the material have been obtained. Physical-chemical analyses were also carried out on concrete specimens. 3. And an also final experimental phase were different types of leaching tests were performed: (1) basic characterization on RPF, and (2) maximum availability and (3) leaching test for the manufactured concrete in monolithic state. Following the processing, analysis and comparison of the results obtained from the tests, the following conclusions could be drawn: 1) mechanical: • The physical properties studied were not significantly affected by the addition of recycled plastic fibres; • The addition of RPF produced a certain decrease in compressive and flexural strength, but an improvement in the post-cracking properties of the concrete was achieved; • The increase in toughness index with an increase in the percentage of recycled plastic fibres confirmed their stitching action inside the cement matrix; • The toughness index presented by the concrete with commercial fibres was greater than that with the same dosage of RPF, due to its rougher surface and greater adherence to the cementitious matrix. Furthermore, it should be noted that the toughness index relative to the mixture with 6 kg of recycled plastic fibres per cubic meter of concrete was comparable to that with commercial plastic fibre (PFRC-REF). This suggests that manufacturing RPF with a rougher surface could lead to a reduction in the amount needed to achieve similar toughness index levels to PFRC-REF; 2) environmental: • Waste plastic food packaging, used for the preparation of plastic sheets to be used as fibre reinforcement in concrete, showed low release levels of the elements determined by the Council Decision 2003/33/EC and they were under the inert limits, except for antimony. Hence, they were classified as nonhazardous material; • The low release levels in concrete with RPF confirms that its incorporation into concrete reduced the concentrations in leachates to a minimum. The concentrations of the elements with higher mobility, in the long-term, were much lower than the limits imposed by regulations for “shaped” construction materials, such as Soil Quality Degree (from The Netherlands); • The study carried out to identify the transport and chemical mechanisms, indicated that the release patterns were: wash-off for Sb, Zn (although Zn also presented depletion in the final steps) and Cr in concrete samples with RPF; dissolution for Ba, except for FRC-REF samples; and diffusion for Cr in FRCREF and C-REF samples; • This type of material did not present any possible environmental impact and could be a viable alternative that would help increase the valorization of such types of plastic waste, which is considered as being one of the biggest concerns worldwide.
Model Predictive Control Applications to Spacecraft Rendezvous and Small Bodies Exploration
(2021-12-01) Sánchez Merino, Julio César; Gavilán Jiménez, Francisco; Vázquez Valenzuela, Rafael; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
The overarching goal of this thesis is the design of model predictive control algorithms for spacecraft proximity operations. These include, but it is not limited to, spacecraft rendezvous, hovering phases or orbiting in the vicinity of small bodies. The main motivation behind this research is the increasing demand of autonomy, understood as the spacecraft capability to compute its own control plan, in current and future space operations. This push for autonomy is fostered by the recent introduction of disruptive technologies changing the traditional concept of space exploration and exploitation. The development of miniaturized satellite platforms and the drastic cost reduction in orbital access have boosted space activity to record levels. In the near future, it is envisioned that numerous artificial objects will simultaneously operate across the Solar System. In that context, human operators will be overwhelmed in the task of tracking and commanding each spacecraft in real time. As a consequence, developing intelligent and robust autonomous systems has been identified by several space agencies as a cornerstone technology. Inspired by the previous facts, this work presents novel controllers to tackle several scenarios related to spacecraft proximity operations. Mastering proximity operations enables a wide variety of space missions such as active debris removal, astronauts transportation, flight-formation applications, space stations resupply and the in-situ exploration of small bodies. Future applications may also include satellite inspection and servicing. This thesis has focused on four scenarios: six-degrees of freedom spacecraft rendezvous; near-rectilinear halo orbits rendezvous; the hovering phase; orbit-attitude station-keeping in the vicinity of a small body. The first problem aims to demonstrate rendezvous capabilities for a lightweight satellite with few thrusters and a reaction wheels array. For near-rectilinear halo orbits rendezvous, the goal is to achieve higher levels of constraints satisfaction than with a stateof- the-art predictive controller. In the hovering phase, the objective is to augment the control accuracy and computational efficiency of a recent global stable controller. The small body exploration aims to demonstrate the positive impact of model-learning in the control accuracy. Although based on model predictive control, the specific approach for each scenario differs. In six-degrees of freedom rendezvous, the attitude flatness property and the transition matrix for Keplerian-based relative are used to obtain a non-linear program. Then, the control loop is closed by linearizing the system around the previous solution. For near-rectilinear halo orbits rendezvous, the constraints are assured to be satisfied in the probabilistic sense by a chance-constrained approach. The disturbances statistical properties are estimated on-line. For the hovering phase problem, an aperiodic event-based predictive controller is designed. It uses a set of trigger rules, defined using reachability concepts, deciding when to execute a single-impulse control. In the small body exploration scenario, a novel learning-based model predictive controller is developed. This works by integrating unscented Kalman filtering and model predictive control. By doing so, the initially unknown small body inhomogeneous gravity field is estimated over time which augments the model predictive control accuracy.
Caracterización y optimización de la producción de alimentos a través de sistemas acuapónicos de pequeña escala
(2021-09-09) Suárez Cáceres, Gina Patricia; Pérez Urrestarazu, Luis; Fernández Cabanás, Víctor Manuel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Departamento de Agronomía
La acuaponía combina la producción de peces (acuicultura) y de plantas (hidroponía), de forma sostenible y en un marco de economía circular, imitando un ecosistema natural complejo. Aunque las instalaciones acuapónicas llevan más de 50 años desarrollándosey pueden construirse con fines comerciales, la perspectiva del autoconsumo también es importante, debido a su alta proliferación en todo el mundo. Sin embargo, hay escasos conocimientos sobre cómo se lleva a cabo la producción acuapónica a pequeña escala y la presencia de productos acuapónicos en los mercados es todavía muy limitada. Los objetivos de esta tesis son: 1) Evaluar la producción acuapónica de un policultivo de diferentes hortalizas, hierbas y frutas junto con tilapias, para autoconsumo, durante todo un año, teniendo en cuenta las limitaciones climáticas durante el verano y el invierno, probando dos alternativas para reducir el consumo de energía en épocas frías. 2) Determinar el perfil y las motivaciones de los productores acuapónicos, las características de las instalaciones y el rendimiento de la producción en España y América Latina. 3) Caracterizar las preferencias de los potenciales consumidores y su disposición a pagar precios más altos por los productos acuapónicos en países hispanohablantes. Esta investigación proporciona una descripción exhaustiva del funcionamiento y manejo de dos Sistemas Acuapónicos de Pequeña Escala (SAPE), autoconstruidos basándose en modificaciones de los propuestos por la FAO. En ellos se produjeron 62 kg de tilapia y 352 kg de 22 verduras y frutas diferentes durante un año, lo que demostró que una instalación acuapónica a pequeña escala puede proporcionar parte de las frutas, verduras y pescado recomendadas para la subsistencia de una familia de cuatro miembros durante todo el año. En relación al pequeño productor acuapónico medio, el perfil más común es el de un hombre de mediana edad, con cierto nivel de estudios y una renta familiar moderada. Las principales motivaciones para tener una instalación acuapónica fueron la producción de alimentos sanos y de alta calidad, la preocupación por el medio ambiente y la autonomía adquirida. Estas motivaciones condicionaron los fines de las instalaciones acuapónicas (principalmente educativos, para autoconsumo y como afición), que, salvo para pequeñas ventas, no tenían un motivo económico. Por sus características, las instalaciones acuapónicas están especialmente adaptadas a la agricultura urbana (muchas de ellas estaban ubicadas en azoteas) y la mayoría de las estudiadas eran de reciente construcción. La técnica de la película de nutrientes fue el subsistema hidropónico más utilizado, seguido de los lechos de medios, donde se produce mayoritariamente un policultivo de hortalizas de hoja y de fruta y aromáticas. La tilapia fue la especie de pez más frecuentemente empleada. En general, los productores carecen de conocimientos y experiencia adecuados sobre estos sistemas complejos para poder operarlos de forma eficiente y existe una necesidad generalizada de formación, particularmente en gestión de plagas y enfermedades y mantenimiento de la calidad del agua. Por último, en cuanto a los consumidores acuapónicos, casi el 60% de los encuestados sabía qué era la acuaponía, y ese conocimiento estaba relacionado con el nivel académico y la preocupación por el medio ambiente. La mayoría de los participantes consideraron la acuaponía como un sistema de producción de alimentos muy interesante. El consumo de productos acuapónicos estaba motivado principalmente por su calidad, sabor y a laausencia de pesticidas o residuos químicos. En cuanto a la disposición a pagar precios más elevados, se constató una notable influencia de los ingresos del hogar, la preocupación por el medio ambiente y, sobre todo, los conocimientos previos sobre acuaponía. Por lo tanto, sería aconsejable realizar campañas publicitarias que proporcionen información específica sobre este tipo de producción de alimentos para aumentar su grado de aceptación del público en general.
Study of the production of drops and their impact on surfaces. Application to the development of an additive manufacturing technique for metals
(2021-09-01) Muñoz Sánchez, Beatriz Natividad; Gañán-Calvo, Alfonso M.; Montanero Fernández, José María; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Drops are constantlyand spontaneouslyproduced in nature, but varied industrial fields (such as biotechnology, chemical engineering, pharmacy, food industry or microbiology) require dropsto be producedin a controlled manner.Furthermore, many applications in these fields benefit whendroplets arevery smallinsize, on the micrometer and even nanometer scale.Consequently, physics of fluids on the submillimeter scale has been intensively developedin the last decades. Within this area, droplet-based microfluidics has demonstrated to be a leading platform to generate and manipulate a wide range of fluid microentities.On the other hand,the impact of droplets happens to becritically important inmany of the scenarios where they are produced, so this phenomenon should be exploredtogether with droplet delivery.Thisapplication-driventhesis, by compilinga series of8 published articles, addresses the controlled production of droplets by severaldroplet-based methods,and their impact onsurfaces.Paper I produces droplets by both Drop on Demandand direct dripping(gravitational) in order to study their impact over moving liquid surfaces.Since a particularly interesting application is the development of additive manufacturing for metals, Paper II produces droplets in direct jettingmode with that potential use.The next contributions (Paper III, Paper IV and Paper V) aim to generate and characterize PDMS microparticles mainly to develop blood analogue fluids. In this case, needle focusingwas used to produce intermediate-state PDMS precursor droplets that will be later cured into solid particles.A common factor among the aforementioned droplet production techniques is the presence of an orifice or nozzle, which becomesa key element to achieve the fragmentation of a continuous liquid phase into droplets. Therefore, nozzle manufacturing was studiedin this thesis through Paper VI and Paper VII.Finally, the major role played by surface tension at microfluidic scales and its dominance on capillary breakup of jets into droplets requires its value to be accurately known. Paper VIII measures the interfacial tensionbetween two immiscible liquids of similar density, with the consequent application to droplet production methods relying on such value.
Assessment and optimization of felt living walls in terms of water retention performance and artificial lighting
(2021) Kaltsidi, Maria Pinelopi; Fernández Cañero, Rafael; Pérez Urrestarazu, Luis; Universidad de Sevilla. Departamento de Ciencias Agroforestales; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Living walls, also referred as green walls or vertical gardens, are becoming a new reality worldwide, mainly in urban areas where the need to increase and enhance green spaces is of vital importance. Green infrastructures, such as living wall systems, can act as additional tools for improving the densely built cities' sustainability or even as a unique choice, in combination with green roof technology, in the case of the complete absence of appropriate terrestrial open spaces where community gardens, parks, urban forests and natural meadows could be installed. Thus, there are various commercial living wall systems and companies R&D departments promoting several innovative technologies. One of their objectives is to enable an adequate development of the living wall vegetation cover with low cost and maintenance needs, ensuring an aesthetically successful and high quality performance in the long term. During the current doctoral thesis, Fytotextile®, a patented felt- based system, and its evolutions were studied in order to assess and optimize their performance in indoor and outdoor living wall installations. Therefore, two studies were conducted in order to evaluate the water management performance of four felt- based living wall systems and to optimize the living wall systems in terms of auxiliary illumination needs. The first study, entitled “Improving the performance of felt- based living wall systems in terms of irrigation management” and published in the journal Urban Forestry & Urban Greening, focused on filling the knowledge gap on the performance of the commercial felt- based living wall system´s irrigation in terms of water management. Hence, the performance of the Fytotextile® commercial living wall system and of three new evolutions based on it was assessed based on the water retention capacity, drying speed and drainage rate, as well as plant performance. The results of the present study highlight (a) the potential of the materials used on felt- based living wall systems to contribute to the improvement of water management with a sustainable approach, (b) the importance of the implementation of the appropriate irrigation schedules and (c) the limited research on the specific field. Specifically, the Fytotextile system with a very highly absorbent engineered polymer fibre blanket (Fytotextile 4) and 4 mm thick geotextile, revealed the most increased capacity to store irrigation water compared to the other three Fytotextile systems. Fytotextile with 4mm thick geotextile (Fytotextile 2) produced the smallest drainage volume in all irrigation schedules. However, all Fytotextile types seemed to be adequate to house the three different vegetation types used (Erodium x variabile 'Roseum', Carex oshimensis 'Evergold', Lavandula dentata), maintaining an elevated aesthetically result in the short term. Erodium x variabile 'Roseum' presented the most satisfactory performance in all Fytotextile systems while Lavandula dentata the least robust. Finally, it is suggested the construction of living walls with suitable and tested materials that can support long life systems with the minimum losses in terms of water and materials (e.g. vegetation, geotextiles) in order to be effective in delivering the desired results. During the second study, entitled “Assessment of different LED lighting systems for indoor living walls” and published in the journal Scientia Horticulturae, six commercial light- emitting diode (LED) lamps (Aster and Dahlia of Ignia Green, Logar CMH, CLH and Forum of Lledó, CF- UT01 of Panda Grow) for indoor installations were evaluated to determine their suitability and efficiency in the performance of living wall systems. CF- UT01 was the only projector designed for plant growth. The evaluation of the illumination was based on lighting pattern, temperature/ water consumption and effect on vegetation performance, along with the observers’ perception for the visual quality of the light. Specifically, two indoor studies were carried out using the Fytotextile® system completely sheltered from sun exposure and two commonly used plant types in indoor living walls (Soleirolia soleirolii and Spathiphyllum wallisii). According to the findings of this study, Illuminance (as luminous flux per unit area) and PPFD were found to be positively correlated to the height of the module for each pocket. Logar CLH Superflood lamp presented the highest value for both traits, while the lowest values were attributed to CF- UT01 lamp. The living wall receiving the Dahlia illumination exhibited the most elevated average daily water consumption and Logar CMH Superflood the lowest. CF- UT01 projector was the only one not characterized as suitable for indoor living walls. Aster and Logar CMH Superflood performed poorly when placed farther from the module and Dahlia was the one that received the highest preference among questionees. Finally, it is highlighted that parameters such as the projector distance from the living wall infrastructure, its orientation, beam angle, energy consumption and the preferable visual quality of the light by the public should also be taken into consideration when evaluating the efficiency of lighting systems.
Studies on the adoption of digitalization and high technology for precision agriculture
(2020-09-07) Lombardo, Stefania; Vieri, Marco; Pérez Ruiz, Manuel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
The study investigates which are the effective approaches for the introduction in the use of new technologies in sustainable precision agriculture and what the necessary networks are for effective technology adoption. At the European level, some studies and research are starting to be carried out to analyze these factors and the actors in the field. The limit of these studies is given by the fact that during the technological revolutions, chaotic situations are determined that do not allow a systematic analysis that a scientific approach requires. It is a fact that new strategies and new approaches are needed for innovations to be introduced with new methodologies not only at research level or on large farms but at small companies level. European countries are responding differently both in terms of speed and actions in terms of introducing innovations. However, the urgency to ensure that to maintain quality and quantity and security we must move from technology is real and cannot be postponed, compared to the forecasts for the development of the planet in environmental and economic and social terms. The innovation of agriculture is not only technological with an eye to the use of technologies but is realized in its sustainability only if it is also economic and social. Therefore innovations cannot be introduced only from a technical point of view but they also influence the economic dynamics of resource and profit management, the planning of corporate planning - with the need to introduce new first-approach tools such as the business model canvases or more structured like lean farming- and social, from the point of view of the typology, quality and quantity not only of the workers that serve to ensure that a system linked to the analogical becomes digital but also from the new role that begin to have the a community of producers and consumers and training and consultancy that is going to change but has not yet fully realized the evolutionary process necessary in the production-consumption model nowadays known.
Probabilistic Aircraft Conflict Detection and Resolution under the Effects of Weather Uncertainty
(2020-09-30) Hernández Romero, Eulalia; Rivas Rivas, Damián; Valenzuela Romero, Alfonso; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
This PhD thesis addresses the problem of aircraft conflict detection and resolution (CD&R) considering weather uncertainty. The general framework of this study is the development of methodologies to integrate weather uncertainty into the Air Traffic Management planning process. The study considers the analysis of both a single pair of aircraft and multi-aircraft conflict scenarios, with two- and three-dimensional trajectories. The weather uncertainty data is retrieved from Probabilistic Weather Forecasts, in particular Ensemble Prediction Systems. Different methodologies to probabilistic CD&R are described, and their applicability is presented and discussed. Firstly, an approach to statistically quantify the severity of aircraft conflicts subject to wind forecast uncertainty is presented. The conflicts are characterized by two indicators: conflict intensity and conflict probability. The conflict intensity is measured by the distance of closest approach between the aircraft. The probability of conflict is obtained in terms of the probability density function of the distance of closest approach, which is obtained from the probability density functions of the wind components using the Probabilistic Transformation Method. The case of two en-route aircraft flying at constant altitude and subject to the same random wind is considered first, and results are presented to analyze the influence the wind uncertainty and the traffic configuration have on the conflict detection problem. Then, this methodology is extended to the problem of three-dimensional multi-segment trajectories and a numerical application is presented. Secondly, a probabilistic method for conflict detection and resolution considering the effects of wind forecast uncertainty is presented. The wind components are modeled as random variables, described by a joint probability density function. The probabilistic conflict detection problem is tackled again using the Probabilistic Transformation Method. The probabilistic conflict resolution consists in modifying the aircraft trajectories so that the probability of conflict between any pair of aircraft be less than a predefined safety threshold. This problem is formulated as a constrained nonlinear programming problem, where the optimality criterion is the minimization of the deviation of the aircraft resolution trajectories from their nominal trajectories and the safety condition, i.e. keeping the conflict probability below a threshold, is enforced as a problem constraint. The case of multiple en-route aircraft flying with constant airspeed and flight level is considered, where they follow approaching multi-segment trajectories and are affected by the same uncertain wind. Numerical results are presented for a particular application and the cost of the resolution process is analyzed. Lastly, a methodology to tackle the problem of strategic aircraft conflict detection and resolution, up to 60 minutes in advance, considering wind and temperature uncertainties is presented. The problem of hundreds of aircraft flying multi-segment 3D trajectories is considered. The conflict detection is based on ensemble trajectory prediction, and it is performed using an efficient grid-based procedure. A metaheuristic approach based on the Simulated Annealing algorithm is developed to solve the conflicts. The proposed CR method generates resolution trajectories by modifying the location of the route waypoints (vectoring), with the objective of lowering the probabilities of the conflicts while also minimising the deviation from the nominal paths. The methodology is then applied to a realistic case study that considers the actual flight plans for hundreds of aircraft in the European airspace; numerical results are presented and analyzed. The work presented in this thesis constitutes a step toward the development of future decision support tools for air traffic controllers that integrate weather uncertainties, expanding the capabilities of conflict detection tools currently in use in Europe and contributing to reduce the negative impact of weather on the safety and efficiency of the air traffic.
Evaluación de la distribución del agua en sistemas de riego por aspersión estacionarios con viento
(2020-02-07) Salvatierra Bellido, Benito; Montero Martínez, J.; Pérez Urrestarazu, Luis; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
En la agricultura de regadío, el parámetro que califica mejor la calidad del riego es la uniformidad del riego. El riego por aspersión presenta una cierta dificultad para calcular la uniformidad de riego en función del diseño, debido a las variables que intervienen en su funcionamiento. Por tanto, estos sistemas de riego requieren de una gran atención en cuanto a la innovación sobre su análisis del riego. Este trabajo se ha iniciado identificando esta necesidad y ha perseguido desarrollar una metodología de análisis de la uniformidad del riego por aspersión para situaciones reales que se den en campo y a través de una base experimental. Con este objetivo, se ha partido de las metodologías existentes y de la tecnología disponible, para obtener una herramienta experimental que cubra las necesidades de conocimiento de la calidad de riego de los sistemas de riego por aspersión estacionarios. Con estas bases, se comenzó, en una primera fase, el diseño y montaje de un banco de pruebas de aspersores que de manera ágil simulara las condiciones reales de riego al aire libre, para así tener una herramienta de análisis capaz de ofrecer valores finales de la calidad de riego en todas las situaciones de riego existentes. Esta tarea ha sido la que ha ocupado la gran parte del desarrollo experimental de este trabajo y ha culminado con el prototipo de un banco automático de ensayos de aspersores con viento. Junto a ello se desarrolló las herramientas correspondientes de análisis de los datos que se obtienen y la puesta a punto final y las necesidades de mantenimiento para el correcto funcionamiento del prototipo. Una vez dispuesto el sistema se continuó con la segunda fase, la adquisición de información con múltiples ensayos de aspersores y cubriendo la demanda de los modelos de aspersores más representativos en el sector. Gracias a la aplicación particular de las metodologías y las herramientas desarrolladas para el tratamiento de datos (superposición de diseños, simulación de múltiples direcciones de viento, y de puesta a punto y calibración del propio banco automático de ensayos), se ha conseguido que el banco automático de ensayo de aspersores sea una herramienta operativa para cualquier iniciativa de mejora en la optimización del agua en riego por aspersión. Los resultados obtenidos sobre el desarrollo del banco automático de aspersores con viento fueron de 29.160 valores de uniformidad de aspersores de uso más frecuente en la agricultura de cultivos herbáceos. Con estos resultados se generó una base de datos con gran capacidad para obtener información y facilidad de ser procesada con los resultados obtenidos directamente de los ensayos. A su vez, estos ensayos permitirán, para situaciones no ensayadas, utilizar una metodología de interpolación de datos experimentales que cubra todas las casuísticas de riego de los aspersores ensayados. En una tercera fase se cuantificó la influencia de las variables que afectan al riego por aspersión en función al tipo de aspersor utilizando el modelo estadístico de regresión lineal múltiple. Al poder ser aplicada a cualquier grupo de aspersores o de situaciones, esta metodología permitirá tomar decisiones estratégicas en relación con diseños, presiones de trabajo, localizaciones óptimas, regímenes de viento, etc. En el estudio abordado se analizaron de manera independiente los siguientes grupos de aspersores: de impacto convencionales con boquillas hexagonales, de impacto con boquillas de bayoneta y rotativos. Para ello, se estudiaron los comportamientos de distintos grupos en relación con todas las variables más relevantes: presencia de boquilla secundaria, velocidad y dirección del viento, presión, distancia entre aspersores y ramales de riego y disposición del marco de riego. En una fase final, y habiendo caracterizado el funcionamiento de gran número de aspersores y detectada la demanda del sector de riego por el ahorro energético, se completó el trabajo con una línea específica e innovadora, en la cual se usó el banco automático de ensayo de aspersores para estudiar el riego por aspersión en condiciones de baja presión. El objetivo perseguido en este desarrollo fue la selección de aquellos aspersores y circunstancias en las con presiones más bajas a las convencionales, obteniéndose buenos valores de uniformidad de riego. El estudio, no sólo se limitó a un análisis de la base de datos de los resultados generados con el banco automático de ensayos, sino que además se hicieron ensayos en campo con evaluaciones múltiples y simultáneas de los aspersores seleccionados para la baja presión (250 y 200 kPa). Finalmente, se estudió el comportamiento de los aspersores seleccionados en toda una campaña de riego con presiones de 200 kPa frente a aspersores en régimen de presión de 300 kPa aproximadamente. La conclusión de esta fase fue la viabilidad del riego a baja presión con aquellos aspersores obtenidos de la base de datos de ensayos del banco automático de ensayos de aspersores con viento.
Global stability analysis of two-fluid flows
(2019-09-11) Carrión Matamoros, Luis Miguel; Herrada Gutiérrez, Miguel Ángel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
The present thesis is a compendium of seven studies devoted to the numerical analysis of nonlinear dynamics and global linear stability of two-fluid flows separated by a continuous interface. The computationally efficient numerical technique developed by Herrada and Montanero [J. Comput. Phys., vol. 306, pp. 137–147, Feb. 2016] is implemented to study the dynamics of capillary one-fluid systems. Instead of using approximation techniques to simplify the two-fluid flows Navier-Stokes equations, the application of this method has the capability of modelling the complete set of governing equations for both fluids in order to obtain the hydrodynamics behavior and the global linear stability analysis.
Development of methodologies to quantify spatial-temporal variability of arable crops for irrigation and fertilization management.
(2019-07-05) Quebrajo Moya, Lucía; Pérez Ruiz, Manuel; Egea Cegarra, Gregorio; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
La creciente preocupación por el papel de la agricultura en la gestión sostenible de los recursos naturales (agua, tierra y atmósfera), combinada con la necesidad de satisfacer la demanda mundial de alimentos, crea una necesidad inmediata de mejorar los sistemas de producción. La conversión de los biosistemas agrícolas en elementos productivos altamente eficientes, económicamente rentables y sostenibles requiere la adopción de tecnología y el uso de datos veraces, repetibles y procesables. En los últimos años, ya se están aplicando e implementando sobre el terreno importantes avances tecnológicos, como los sistemas de posicionamiento globales (GPS), los monitores de rendimiento, las tecnologías de tasa variable (VRT) y otros sensores. Esta tecnología se está incorporando a la producción de cultivos en todas sus fases: siembra, fertilización, control de plagas y malas hierbas, riego, recolección, etc., para obtener la máxima información posible de cada una de ellas y permitir un manejo preciso y específico. Los avances en las diferentes estrategias y decisiones que se toman diariamente en los sistemas de producción son claves para obtener la máxima rentabilidad al menor coste posible, que es el principal objetivo de cualquier productor. El objetivo principal de esta tesis doctoral es desarrollar nuevas metodologías de información de manejo específico para caracterizar la variabilidad espacial y temporal en rasgos clave del suelo y del cultivo en dos cultivos herbáceos de gran importancia económica en Andalucía, la remolacha azucarera de siembra otoñal y el trigo duro de invierno. Dado que la remolacha azucarera es un cultivo de regadío y el trigo duro es normalmente un cultivo de secano, este trabajo se ha centrado en el desarrollo de herramientas para optimizar la gestión del riego de la remolacha azucarera y la fertilización del trigo duro. Por un lado, se ha evaluado la viabilidad de utilizar un sensor óptico portátil y económico para (1) estimar la respuesta del rendimiento del trigo a la fertilización con N y (2) generar mapas de prescripción de las recomendaciones de aplicación de N para los campos de trigo comerciales. Por otra parte, las imágenes capturadas con una cámara térmica montada en un vehículo aéreo no tripulado (UAV) se utilizaron para evaluar su potencial para caracterizar la variabilidad espacio temporal del estado hídrico de la remolacha azucarera cuando se cultiva en condiciones heterogéneas de gestión del suelo y del agua.
Forcing microbubbles in microfluidics
(2019-06-11) Arcos González Turmo, Irene de; Castro Hernández, Elena De; Gañán-Calvo, Alfonso M.; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
The present thesis is a compilation of three studies in the field of microfluidic, more concretely, the generation of microbubbles and the effect that different applied forces have on them. A microbubble generation state of the art in terms of applications, employed fluids, working regimes and microfluidic devices is introduced in the first place. Several microfluidic devices: cross junction, TJunction, planar and axisymmetric flow focusing are compared with regard to their operational woking regime -bubbling, jetting or squeezing- and achievable microbubble size, as well as their fundamental advantages and limitations. In the second chapter, a novel swirl flow-focusing microfluidic axisymmetric device for the generation of monodisperse microbubbles at high production rates is presented. By forcing a swirl effect on the liquid stream, a more stable production, as well as a microbubble size reduction -up to 57% compared to the axisymmetric flow focusing-, is achieved due to the enhanced gas meniscus stability. The swirl is shown to expand the bounds of the jetting mode inhibiting the bubbling mode. An experimental study is performed for various blade angles -0º, 40º, 60º and 80º- and numerous gas to liquid flow rate ratios, validating previous numerical simulations and previous flow-focusing scaling law proposed by Gañán- Calvo [Gañán-Calvo, Physical Review E, 2004, 69(2), 027301]. Chips with 60º blades exhibit the best combination of swirl effect and robustness against perturbations. Chapter three is devoted to the active control of microbubble size on planar flow-focusing devices by means of an acoustic streaming or mechanical excitation. Few numerical studies have been reported so far, despite the invaluable information that computational analysis can through on this topic. In this chapter, the microbubble generation is numerically analyzed for an ample range of acoustic accelerations and frequencies and for several contact angles. A bubble volume change of 20% when sweeping between 25º and 120º was observed. The addition of an acoustic excitation showed a correlation between the frequency and the highest amplitude that the system can absorbed without collapsing. Likewise, bubble size increases with the excitation amplitude. A theoretical framework for the physics and parametric description of that tuning is also presented. Finally, the effect of the acoustic excitation, not on bubble generation, but on a pinned microbubble in the low-energy regime is experimentally analyzed. Here, the goal is not to modify the bubble size, but to characterize liquid properties based on the bubble oscillation for medical diagnosis application. The novel Digital Holographic Microscope (DHM) is used for measuring the bubble interface movement and an unwrapping and mode recognition code is specifically developed for this chapter. Modes shapes and resonance frequencies were identified and related to the liquid surface tension to obtain a surface tension approximation. At the moment, further noise-reduction procedures as well as a viscosity relation to the bubble oscillation are being developed.
Micro/nano liquid ejection via electrohydrodynamic fields and gaseous streams. Application in structural biology with xfel
(2019-06-11) Cruz-Mazo, Francisco; Gañán-Calvo, Alfonso M.; Montanero Fernández, José María; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Fragmentación de corrientes gaseosas y de masas líquidas en flujos naturales y de interés tecnológico
(2019-04-05) Sánchez Quintero, Enrique Jesús; Gordillo Arias de Saavedra, José Manuel; Riboux Acher, Guillaume; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
New strategies for row-crop management based on cost-effective remote sensors
(2017-09-12) Martínez Guanter, Jorge; Agüera Vega, Juan; Pérez Ruiz, Manuel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Agricultural technology can be an excellent antidote to resource scarcity. Its growth has led to the extensive study of spatial and temporal in-field variability. The challenge of accurate management has been addressed in recent years through the use of accurate high-cost measurement instruments by researchers. However, low rates of technological adoption by farmers motivate the development of alternative technologies based on affordable sensors, in order to improve the sustainability of agricultural biosystems. This doctoral thesis has as main objective the development and evaluation of systems based on affordable sensors, in order to address two of the main aspects affecting the producers: the need of an accurate plant water status characterization to perform a proper irrigation management and the precise weed control. To address the first objective, two data acquisition methodologies based on aerial platforms have been developed, seeking to compare the use of infrared thermometry and thermal imaging to determine the water status of two most relevant row-crops in the region, sugar beet and super high-density olive orchards. From the data obtained, the use of an airborne low-cost infrared sensor to determine the canopy temperature has been validated. Also the reliability of sugar beet canopy temperature as an indicator its of water status has been confirmed. The empirical development of the Crop Water Stress Index (CWSI) has also been carried out from aerial thermal imaging combined with infrared temperature sensors and ground measurements of factors such as water potential or stomatal conductance, validating its usefulness as an indicator of water status in super high-density olive orchards. To contribute to the development of precise weed control systems, a system for detecting tomato plants and measuring the space between them has been developed, aiming to perform intra-row treatments in a localized and precise way. To this end, low cost optical sensors have been used and compared with a commercial LiDAR laser scanner. Correct detection results close to 95% show that the implementation of these sensors can lead to promising advances in the automation of weed control. The micro-level field data collected from the evaluated affordable sensors can help farmers to target operations precisely before plant stress sets in or weeds infestation occurs, paving the path to increase the adoption of Precision Agriculture techniques.

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