Listar Theses & Dissertations por título
Mostrando ítems 1716-1735 de 4032
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Fabricación y caracterización de películas de dióxido de vanadio (VO2) depositadas por sputtering con corriente continua pulsada
(2011)Thin films of vanadium dioxide were grown on glass and sapphire substrates by the pulsed-dc sputtering technique. This compound is of great interest because it exhibits a semiconductor (monoclinic phase) to metal (tetragonal ... -
Fabricación Y Caracterización De Películas De Óxido De Zinc Dopado Con Elementos Magnéticos
(2009)Previous Works had predicted that ZnO doped with 3d transition metals can exhibit ferromagnetism at room temperature, which can be used in spintronics applications. Based in this motivation we started preparing targets of ... -
Fabricación y caracterización de películas delgadas de sesquióxido de vanadio (V₂0₃) crecidas sobre sustratos de Si0₂ y Al₂0₃ para los cortes A, M, C y R.
(2017)In this research thin films of vanadium sesquioxide (V₂0₃) were produced by the magnetron sputtering DC technique. The films were deposited on Si0₂ glass substrate and Al₂0₃ crystals in A, M, C and R cuts. The analysis of ... -
Fabricación y caracterización de películas delgadas de sesquióxido de vanadio dopado con cromo
(2018-12-12)Thin V2O3 films were deposited on SiO2 by reactive DC magnetron sputtering. The films deposited under nominally identical conditions exhibited significant differences in electrical characteristics. The samples were ... -
Fabricación y estudios de las propiedades físicas de películas delgadas de sesquioxide de vanadio
(2009)In this work V2O3 thin films were grown on Al2O3(0001??) and LiTaO3 (0001) substrates by using the Pulsed Laser Deposition (P.L.D) technique. The crystal structure of the thin films was studied through X Ray Diffraction ... -
Fabrication and characterization of bioferroelectric composites
(2015)Bio-ferroelectric composites have recently sparked intensive research in order to develop inexpensive and environmental electronic devices such as capacitors, transistors, and actuators. The present research involves the ... -
Fabrication and characterization of chitin-carbon nanotubes composites
(2015)Most polymers by themselves have limitations due to their poor mechanical, thermal and electrical properties compared with metallic and ceramic materials. Therefore, to expand their range of applications these properties ... -
Fabrication and characterization of functionally graded Al/AlB2 matrix composites for high wear aerospace applications using centrifugal casting
(2006)Functionally graded advanced composite materials contain reinforcement particles whose volume fraction varies continuously thereby bearing a non-uniform microstructure with continuously changing properties. Aluminum-based ... -
Fabrication and characterization of porous aluminum and zinc via selective dissolution of AI-Zn alloys
(2013)Chemical dealloying can be used to fabricate porous metals by removing one or more of the species out of an alloy. Generally, a corrosive electrolyte is used to selectively dissolve a noble element. Alloy concentration, ... -
Fabrication and characterization of sintered recycled glass designed for polluted soil filtering
(2014-07)Soil pollution generates diseases, hunger, and agricultural problems. Porous recycled glass beds were produced to study the feasibility of using them for polluted soil filtering. This research discusses structural and ... -
Fabrication and characterization of VO2 thin films using pulsed DC magnetron sputtering
(2015)Vanadium dioxide (VO2) is one of the many oxide phases of vanadium, which exhibits a semiconducting monoclinic stable phase up to 68°C. At temperatures over ~68°C the stable phase for VO2 is tetragonal and exhibits metallic ... -
Fabrication of porous metals via selective phase dissolution of an Al-Cu alloy
(2018-06-01)Through free corrosion in sodium hydroxide, a new porous material was successfully fabricated by removing a single phase of the aluminum-copper alloy. This selective phase dissolution was performed for the eutectic composition ... -
Fabrication of VO2 (B) thin films by pulsed DC reactive magnetron sputtering and characterization at low and high temperatures
(2018)For this work, VO2 (B) thin films were fabricated using pulsed DC magnetron reactive sputtering. The technique belongs to the ionic sputtering methods which allows high deposition rates, high-purity films, excellent ... -
Fabrication, characterization and testing of functionally graded aluminum-based targets for sputtering deposition of hybrid composites
(2011)The fabrication, characterization and testing of sputtering targets were completed for the deposition of hybrid composites. The chemical composition of the target specimens consisted of an aluminum-silicon matrix reinforced ... -
Facies distribution model and sequence stratigraphic model of mid tertiary rocks exposed in east side of Guanica Bay, Puerto Rico
(2013)A sequence stratigraphic model and facies distribution model was created for Middle- Tertiary rocks exposed on the east side of Guánica Bay. The models are based on lithology, fossil content, integrated with microfacies ... -
Facing her fears: Analyzing monsters in the early Female Gothic
(2020-11-04)This thesis focuses on the representation of the monstrous in Female Gothic literature of the late 18th Century and early 19th Century. The focus of this research is on three novels: The Italian by Ann Radcliffe, Zofloya ... -
Factores críticos en ambientes de aprendizaje híbrido: una mirada desde los estudiantes doctorales
(2021-05-10)El aprendizaje híbrido es entendido como la combinación de los mejores elementos del aprendizaje presencial (face-to-face) y del aprendizaje en línea (Chaeruman et al., 2018). Esta investigación indagó las percepciones de ... -
Factores de apoyo social y sintomatología depresiva en adultos mayores de minorías étnicas
(2022-05-13)Introducción: El apoyo emocional y el instrumental han sido identificado como factores protectores para la salud mental. Se han llevado a cabo estudios evaluando el apoyo social con minorías étnicas, pero son escasas las ... -
Factores de calidad de servicio para el sistema de carros públicos
(2010-12)The “Carros Públicos” is a special demand response transit service operating in Puerto Rico. The sustained reduction in the system ridership could be related to its poor quality of service, as perceived by the population, ... -
Factores de riesgo asociados al desarrollo de la depresión postparto en madres residentes de Puerto Rico
(2022-05-26)Trasfondo: En países subdesarrollados con precarias condiciones sociales, económicas y políticas, la depresión postparto (DPP) es más común. La prevalencia de la DPP en estos lugares es más grave, afectando a más del 25% ...