Arreglos de antenas para radiación tipo Isoflux en satélites LEO con diferentes alturas orbitales

Antenna arrays for Isoflux radiation in LEO satellites at various orbital altitudes

Paulina Díaz De la Paz (2023, [Tesis de maestría])

En los últimos años, las constelaciones de satélites en órbita baja han ganado popularidad como infraestructura para ofrecer el servicio de Internet satelital, y se espera que su presencia siga en aumento. Para minimizar la latencia en la transmisión de datos, estos satélites suelen situarse en el rango inferior y medio de la órbita baja terrestre. Comúnmente, los satélites de estas constelaciones emiten una radiación que consiste en un único haz que concentra la potencia en una sola dirección. Sin embargo, debido a la curvatura de la Tierra, las ondas electromagnéticas radiadas por el arreglo de antenas abordo del satélite viajan distancias diferentes. Las ondas que se desplazan en dirección del nadir del satélite hacen un recorrido más corto en comparación con las que se propagan en las direcciones más distantes a este. Este fenómeno ocasiona pérdidas de potencia en los bordes del área de cobertura. Para compensar estas pérdidas, se propone el uso de arreglos de antenas de radiación tipo Isoflux. Estos arreglos distribuyen la densidad de potencia de manera uniforme en el área de cobertura, aumentando la ganancia en direcciones donde el trayecto es más largo. Lograr este tipo de radiación para satélites en órbita baja se vuelve más desafiante. Debido a la proximidad del satélite a la Tierra, es necesario que la radiación se extienda sobre una gran parte del plano de elevación, requiriendo un haz Isoflux que sobrepasa los 100 grados. Esta tesis presenta 18 diseños de arreglos de antenas para satélites en las alturas orbitales de 340 km, 550 km y 1150 km. Para el diseño de estos arreglos, se emplean las geometrías lineales, planares y anillos concéntricos, tanto periódicas como aperiódicas. La distribución de excitaciones de amplitud y la separación entre elementos de antena se optimizan utilizando algoritmos genéticos. La presente tesis incluye un análisis comparativo de las prestaciones de radiación y cantidad de elementos de los diseños presentados, categorizados por altura orbital.

In recent years, the utilization of low-Earth orbit satellite constellations as infrastructure for providing satellite Internet services has experienced substantial growth. The rise of this trend is likely to continue. These satellites are typically placed in the lower to mid-range of low-Earth orbit in order to reduce latency in data transmission. It is common for the antenna arrays on these satellites to emit a single radiation beam that concentrates power in a singular direction. Due to the curvature of the Earth, the electromagnetic waves radiated by the antenna array travel different distances. Waves traveling in the satellite’s nadir direction cover a shorter distance compared to those propagating in more distant directions. This phenomenon causes power losses at the edges of the coverage area. To compensate for these losses, the use of Isoflux radiation antenna arrays is proposed. These arrays distribute the power density evenly across the coverage area, increasing gain in directions where the path is longer. Achieving such radiation characteristics becomes more difficult for low-Earth orbit satellites. Due to the satellite’s proximity to Earth, radiation needs to extend over a large portion of the elevation plane, requiring an Isoflux beam that exceeds 100 degrees. This thesis presents 18 antenna array designs for satellites at the orbital altitudes of 340 km, 550 km, and 1150 km. Linear, planar, and concentric ring geometries are employed, with both periodic and aperiodic antenna element distributions. The distribution of amplitude excitations and the spacing between antenna elements are optimized using genetic algorithms. This thesis includes a comparative analysis of the radiation performance and the number of elements of the presented designs, categorized by orbital altitude.

arreglos de antenas, radiación Isoflux, satélites LEO, algoritmos genéticos antenna arrays, Isoflux radiation, LEO satellites, genetic algorithms INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA ELECTRÓNICA ANTENAS ANTENAS

Obtención de combustible sostenible de aviación a partir de Aceite de Cocina Usado y lípidos de Coelastrella sp CORE3

STEPHANIE MICHELLE VILLAFAN CACERES (2023, [Tesis de maestría])

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA ENERGÉTICA FUENTES NO CONVENCIONALES DE ENERGÍA FUENTES NO CONVENCIONALES DE ENERGÍA

Object manipulation by collaborative autonomous underwater vehicles driven by a model-free second-order sliding mode controller with finite-time convergence

JOSUE GONZALEZ GARCIA (2023, [Artículo])

https://orcid.org/0000-0001-5657-380X

The use of Autonomous Underwater Vehicles (AUV) has expanded in recent years to include them in inspection, maintenance, and repair missions. These missions require the automation of tasks such as autonomous navigation and station-keeping, which are pretty challenging due to the complexity of the vehicle itself and the underwater environment. Traditional control strategies have been used to deal with those problems before, but their performance is limited since they do not consider non-linearities, external disturbances, or model uncertainties. Non-traditional controllers have been explored too, but have shortcomings such as being model-based, parameter-dependant, or so. Additionally, the nature of some objects implies the involvement of multiple vehicles to manipulate them, making the manipulation mission even harder. Collaboration of AUVs is a strong challenge since underwater communications are limited or null. An advanced control strategy dealing with the trajectory tracking and the station-keeping problem would be desirable for simplicity and robustness. If this controller could also help coordinate multiple vehicles without requiring them to communicate with each other, it would make collaborative manipulation tasks reachable. For this purpose, a model-free high-order Sliding Mode Controller (SMC) is presented in this project. Unlike other control approaches, the proposed control strategy achieves finite-time convergence to a practical zero error in a time-base that the user can arbitrarily define. This characteristic will be used to coordinate the navigation of two AUVs to manipulate an object underwater. The performance of the proposed controller was evaluated by numerical simulations and experiments in a semi-Olympic swimming pool and compared with classic and state-of-the-art control strategies regarding trajectory tracking and station-keeping problems. Results have shown that the proposed controller can achieve finite-time convergence of the tracking errors to a practical zero value in the predefined time-base. Results also demonstrated that the convergence time could be arbitrarily selected by the user and achieved by the controller resulting in, as far as the author knows, the first controller with this characteristic for AUVs navigation. The simulations and experiments also showed that the proposed controller outperformed classical and state-of-the-art controllers regarding the Root Mean Square of the tracking errors and energy consumption. Finally, the proposed model-free high-order SMC coordinated two BlueROV2 vehicles in a collaborative manipulation mission without vehicle-to-vehicle communication. Numerical simulation results confirmed that the proposed controller could manage the vehicles to follow a predefined coordinated trajectory to approach, grip, transport, and release an object without communicating with each other.

Doctor of Philosophy In Engineering Science

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE LA INSTRUMENTACIÓN INGENIERÍA DE CONTROL INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA NAVAL VEHÍCULOS SUBMARINOS

EFFICIENT FLUORESCENT AND PHOSPHORESCENT OLEDs BY SPIN COATING TECHNIQUE AND A NEW ANODE BASED ON CONDUCTIVE PEDOT:PSS

Luis Abraham Lozano Hernández (2020, [Tesis de doctorado])

"Fluorescent and phosphorescent Organic Light Emitting Diode (OLED) devices were fabricated by solution process and optimized. From their basic characterization (J-V-L curves, electroluminescence spectra) external quantum efficiency (EQE) was calculated. Two small molecule, carbazole derivatives (CZ-1 and CZ-2), previously reported and used for OLEDs showed very good luminances (~ 4000 cd/m2) and current densities (< 200 mA/cm2) resulting in a high EQE (9.5 %). Likewise, fluorescent OLEDs based in the new polymer PF-2F presented an acceptable performance even on a simple architecture with a good EQE (2.6 %), photoluminescence quantum yield (PLQY) about 1 and excellent properties of processability. The influence of its CF3 group in the optical, chemical, electronic and mechanical properties in OLEDs was determined.

Also, a new family of three fluorescent oligomers (BT-F32, BT-F42 and BT-F52) with excellent properties in solution, high PLQY (~1) and highly luminescent, were used in simple and multilayer OLEDs achieving a very high luminance (29 499 cd/m2). These oligomers have different chain lengths, which influence the device luminance, efficiency and their lifetime. Lifetime was monitored and the stretched exponential decay (SED) model was used in order to obtain the device half-life (LT50). Also, phosphorescent devices, based on a host/guest system (PVK:Ir(ppy)3), were prepared, the influence of the electron transport layer (ETL) into the electron/hole ratio was analyzed.

By using a new proposed method, a PEDOT:PSS anode was developed and applied in rigid and flexible substrates, with low sheet resistance (40 Ω/□) and acceptable transmittance (> 85%). This new proposed method consists in volume evaporation, in which basically the loss of water induces closeness among the conductive fractions of PEDOT. This PEDOT:PSS anode easy of fabricating following an economical procedure could be applied not just in OLEDs but in other optoelectronic devices such as organic photovoltaic cells (OPVs), perovskite solar cells (PeSCs), etc."

OLEDs Fluorescence Phosphorescence PEDOT:PSS Polymer Anode INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA ELECTRÓNICA DISPOSITIVOS SEMICONDUCTORES DISPOSITIVOS SEMICONDUCTORES

Validación del uso de energía renovable para su aplicación en el subsector agrícola

JOSE JASSON FLORES PRIETO Olga Xochitl Cisneros Estrada (2013, [Documento de trabajo])

Desarrollo tecnológico para la desalación de agua salobre con generación híbrida de paneles solares y aerogeneradores – Sistema de bombeo solar para riego presurizado – Sistema de desalación solar por nanofiltración – Referencias bibliográficas.

Energía solar Tecnología apropiada Desalación Nanofiltración Riego Informes de proyectos INGENIERÍA Y TECNOLOGÍA

Physical exertions recognition using surface electromyography and inertial measurements for occupational ergonomics

HUGO GUSTAVO GONZALEZ HERNANDEZ (2022, [Tesis de maestría])

Automation of ergonomic risk level assessments using predictive models is limited to the recognition of certain activities with the intention of calculating some ergonomic risk factors, this means that the predictive models are only useful to recognize the activities that were taught. In this thesis, a framework was developed to automatically recognize the physical exertions done by an

operator during a manual work task towards the automation of Job Strain Index (JSI) assessment. The framework includes the use of a wearable device that captures surface electromyography (sEMG) signals and inertial measurements called Mindrove armband, and provides the data treatments that maximized the training accuracy of a Cubic Support Vector Machine (CSVM) model, which was responsible for predicting the exertions depending on the behavior of the data. To determine the best data treatments, full factorial experiments were designed and analyses of variance (ANOVA) were performed. Thus, the best data treatments to obtain a maximum average training accuracy of 93.29% and testing accuracy of 94.31% of the CSVM were the filtering of raw signals with a 4th order Butterworth filter, the rectification of sEMG signals, the outliers' removal in data via Hampel identifier, the computation of the RMS envelope and normalization of sEMG, the zero calibration for inertial measurements, and the extraction of 126 statistical features. Additionally, the Visual Signal Analyzer App (SIANA) was developed for data processing, which works under the proposed framework. Automatic recognition of any physical exertion means that an automated JSI can

be applied to any manual work task, thereby identifying more quickly the risk level of a work task in order to modify it to avoid occupational diseases and accidents.

Master of Science in Engineering

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA INDUSTRIAL EQUIPO INDUSTRIAL

Síntesis y caracterización de biocarbones obtenidos a partir del Eichhornia crassipes y dopados con heteroátomos de nitrógeno

MONICA GUADALUPE RUIZ SALAZAR (2024, [Tesis de maestría])

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA ENERGÉTICA ENERGÍA ENERGÍA

Agua, gobierno y minería: ¿Por qué el medio ambiente no es prioridad en la agenda pública?

ANA MARIA HERRERA CRUZ JUAN ANTONIO BARRON SEVILLA (2022, [Artículo])

Valorar la escasez del agua, la regulación gubernamental y a la minería, es poner en la balanza la famosa relación costo beneficio. No es necesario ser un erudito para saber cuál es la elección de nuestros gobiernos Prevaleciendo en este caso la economía y un aparente desarrollo contra la preservación del medio ambiente. Lo que resulta urgente es un nuevo planteamiento de prioridades para la resolución de problemas que aquejan el acceso al agua como derecho humano.

ESCASEZ DEL AGUA IMPACTO MINERO MEXICO POLITICAS AMBIENTALES INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA MINERA OTRAS OTRAS

Los retos de la adopción tecnológica en el sector hídrico de Latinoamérica

ROBERTO ROMERO PEREZ DENISE SOARES (2014, [Libro])

Esta publicación concentra las ponencias presentadas en el seminario-taller, llevado a cabo en la Ciudad de México en diciembre de 2013 y que tuvo como objetivo el intercambio de experiencias entre especialistas en proceso de adopción social de tecnologías en el sector hídrico de Latinoamérica.

Recursos hídricos Tecnología apropiada Transferencia de tecnología América Latina CIENCIAS SOCIALES

Desarrollo, adaptación y evaluación de tecnologías alternativas

AXEL FALCON ROJAS LILIANA GARCIA SANCHEZ Edson Baltazar Estrada Arriaga (2020, [Documento de trabajo])

En este proyecto se evalúa el sistema de tratamiento de aguas residuales del modelo experimental de la casa ecológica rural del Instituto Mexicano de Tecnología del Agua, la cual cuenta con un humedal artificial horizontal como etapa principal del tratamiento. Con esta evaluación se busca generar distintas configuraciones del sistema que puedan adaptarse a las necesidades y espacios disponibles de las zonas rurales y periurbanas de México.

Tecnologías apropiadas Tratamiento de aguas residuales INGENIERÍA Y TECNOLOGÍA