<p>  </p> <p>Water scarcity is a global problem impacting a majority of the world population. A significant proportion of the global population is deprived of clean drinking water, an impact felt by the rural as well as urban population. Saltwater desalination provides an attractive option to produce clean water. Some technologies to generate potable water include reverse osmosis (RO), multi-stage flash distillation (MSF), vapor compression distillation and multi-effect distillation (MED). Distillation plants such as those in MED often have falling-film evaporators operating at low energy conversion efficiency and hence distillation is performed over multiple stages (or effects). Porous materials can be utilized as evaporators in such plants with the objective of leveraging their superior efficiency. This can potentially decrease the number of effects over which distillation occurs. However, evaporation of high-salinity salt solution eventually results in salt precipitation which can cause fouling and induce structural damages, especially if the precipitates appear within the porous medium. Crystallization-induced structural damages are also of significant concern to building materials and for their role in weathering of historical monuments. It is thus crucial to understand the mechanisms governing salt precipitation in a porous medium.</p> <p>Transport of solute in such a medium is either driven by flow of the solution (advection) or by concentration gradients (diffusion). The dynamics of solute transport is further complicated due to the involvement of a reaction term accounting for any salt precipitation. The relative strengths of these driving forces determine the solute transport behavior during an evaporation-driven process. The wide-scale applications of solute transport and its complicated nature warrant investigation, both experimental and theoretical, of the dependence of solute transport and the subsequent precipitation on the operating conditions and the properties of the porous medium.</p> <p>This dissertation first focuses on developing a novel modeling framework for evaluating the transient behavior of the solute mass fraction profile within the domain of a one-dimensional porous medium, and extending its capability to predict the formation of salt precipitate in the medium.  Experimental investigations are then performed to study the formation of precipitate on sintered porous copper wicks of different particle-size compositions, and developing a mechanistic understanding of the governing principles.</p> <p>A numerical modeling framework is developed to analyze evaporation-driven solute transport. Transient advection-diffusion equations govern the salt mass fraction profile of the solution inside the porous medium. These governing equations are solved to obtain the solute mass fraction profile within the porous medium as well as the effloresced salt crust. Further accounting for precipitation allows a study of the formation and growth of efflorescence and subflorescence. Crystallization experiments are performed by allowing a NaCl solution to evaporate from a porous medium of copper particles and the subflorescence trends predicted by the model are validated. The modeling framework offers a comprehensive tool for predicting the spatio-temporal solute mass fraction profiles and subsequent precipitation in a porous medium.</p> <p>The dependence of efflorescence pattern on the properties of a porous medium is also investigated. Efflorescence patterns are visually observed and characterized on sintered copper particle wicks with spatially unimodal and bimodal compositions of different particle sizes. Efflorescence is found to form earlier and spread readily over a wick made from smaller particles, owing to their lower porosity, while it is limited to certain areas of the surface for wicks composed of the larger particles. A scaling analysis explains the observed efflorescence patterns in the bimodal wicks caused by particle size-induced non-uniform porosity and permeability. The non-uniformity reduces the advective flux in a high-permeability region by diverting flow towards a low-permeability region. This reduction in advective flux manifests as an exclusion distance surrounding a crystallization site where efflorescence is not expected to occur. The dependence of this exclusion distance on the porosity and permeability of the porous medium and the operating conditions is investigated. A large exclusion distance associated with the regions with bigger particles in the bimodal wicks explains preferential efflorescence over the regions with smaller particles. This novel scaling analysis coupled with the introduction of the exclusion distance provides guidelines for designing heterogeneous porous media that can localize efflorescence.</p> <p>Additionally, droplet interactions with microstructured superhydrophobic surfaces as well as soft surfaces were investigated during the course of this dissertation, separate from the above investigations. These investigations involve the interplay of surface energies with electrical or elastic energies and are studied both experimentally and through theoretical models, and therefore are retained as additional chapters in the thesis as being of relevant interest.  Electrowetting experiments are performed on superhydrophobic surfaces with re-entrant structures to study their resilience to the Cassie-to-Wenzel transition. The deformation of soft surfaces caused by forces exerted by microscale droplets is studied and the resulting interaction between multiple droplets is explored. </p>

El desarrollo de modelos matemáticos predictivos de distinto tipos de fenómenos son aplicaciones fundamentales y útiles de las técnicas de Minería de Datos. Un buen modelo se convierte en una excelente herramienta científica que requiere de la existencia y disposición de grandes volúmenes de datos, además de habilidad y considerable tiempo aplicado del investigador para integrar los conocimientos más relevantes y característicos del fenómeno en estudio. En el caso concreto de ésta tesis, los modelos de predicción desarrollados se enfocaron en la predicción contaminantes ambientales como el valor medio de Partículas Finas (PM2.5) presentes en el aire respirable con un tiempo de anticipación de 8 horas y del Ozono Troposférico Máximo (O3) con 24 horas de anticipación. Se trabajó con un interesante conjunto de técnicas de predicción partiendo con herramientas de naturaleza paramétrica tan sencillas como Persistencia, Modelación Lineal Multivariante, así como la técnica semi-paramétrica: Regresión Ridge además de herramientas de naturaleza no paramétrica como Redes Neuronales Artificiales (ANN) como Perceptron Multicapa (MLP), Perceptrón Multi Capa Cuadrática (SMLP), Función de Base Radial (RBF) y Redes Elman, así como Máquinas de Vectores Soporte (SVM), siendo las técnicas no paramétricas las que generalizaron mejor los fenómenos modelizados. / Salazar Ruiz, E. (2008). Desarrollo de modelos predictivos de contaminantes ambientales [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/2504

<p dir="ltr">The Intermontane terranes represent one of the largest composite accreted terranes that built the northern Cordillera. To better understand the interactions between the continental margin of Laurentia and the Intermontane terranes, this study analyzes twelve detrital zircon samples (n=3232) from a Neoproterozoic (?) to Cretaceous metasedimentary stratigraphic section exposed in central Alaska. Distinct detrital zircon populations have been identified and are interpreted to represent four stages in the geologic development of this part of western North America. Stage 1 extends from the Neoproterozoic (?) to the Early Paleozoic, and is characterized by Proterozoic and Archean detrital zircon populations that correlate with Laurentian sources of sediment. We interpret Stage 1 to represent deposition along the northwestern continental margin of Laurentia. Stage 2 extends from the Silurian (?) to the Devonian and is characterized by a dominant Devonian and Silurian detrital zircon population. We interpret Stage 2 to have been deposited in a backarc basin coeval with active volcanism as the Yukon-Tanana terrane was rifted away from the Laurentian continental margin as the Slide Mountain Ocean opened. Stage 3 extends from the Mississippian to the Jurassic and records a shift back to sediment sources with abundant Proterozoic and Archean zircon. We interpret this stage to represent deposition of Laurentian detritus along the eastern margin of the Slide Mountain Ocean basin. Stage 4 is represented by the Lower Cretaceous strata of the Manley basin that contain one major Late Triassic to Early Jurassic detrital zircon population. We interpret this population to be sourced from the syn-collisional and post-collisional Late Triassic to Early Jurassic plutons and related sedimentary basins of the Intermontane terranes that were exhumed and eroded during the closure of the Slide Mountain Ocean and the subsequent collision with the Laurentian continental margin. We interpret the Manley basin as a syn- to post-collisional extensional basin associated with regional detachment faults that formed because of crustal thickening in the collisional zone. From a regional perspective, an extensive clastic wedge prograded northward away from the zone of crustal thickening and can be identified in a series of Mesozoic sedimentary basins that are discontinuously exposed over 1500 km in southern Alaska. Results of our study better delineate the tectonic processes that set the framework for the construction of the Late Mesozoic and Cenozoic Cordilleran orogen.</p>

This thesis tackles issues of particular interest regarding analysis and design of passive components at the mm-wave and Terahertz (THz) bands. Innovative analysis techniques and modeling of complex structures, design procedures, and practical implementation of advanced passive devices are presented. The first part of the thesis is dedicated to THz passive components. These days, THz technology suffers from the lack of suitable waveguiding structures since both, metals and dielectric, are lossy at THz frequencies. This implies that neither conventional closed metallic structures used at microwave frequencies, nor dielectric waveguides used in the optical regime, are adequate solutions. Among a variety of new proposals, the Single Wire Waveguide (SWW) stands out due to its low attenuation and dispersion. However, this surface waveguide presents difficult excitation and strong radiation on bends. A Dielectric-Coated Single Wire Waveguide (DCSWW) can be used to alleviate these problems, but advantages of the SWW are lost and new problems arise. Until now, literature has not given proper solution to radiation on bends and, on the other hand, rigorous characterization of these waveguides lacks these days. This thesis provides, for the first time, a complete modal analysis of both waveguides, appropriated for THz frequencies. This analysis is later applied to solve the problem of radiation on bends. Several structures and design procedures to alleviate radiation losses are presented and experimentally validated. The second part of the thesis is dedicated to mm-wave passive components. These days, when implementing passive components to operate at such small, millimetric wavelengths, to ensure proper metallic contact and alignment between parts results challenging. In addition, dielectric absorption becomes significant at mm-wave frequencies. Consequently, conventional hollow metallic waveguides and planar transmission lines present high attenuation so that new topologies are being considered. Gap Waveguides (GWs), based on a periodic structure introducing an Electromagnetic Bandgap effect, result very suitable since they do not require metallic contacts and avoid dielectric losses. However, although GWs have great potential, several issues prevent GW technology from becoming consolidated and universally used. On the one hand, the topological complexity of GWs difficulties the design process since full-wave simulations are time-costly and there is a lack of appropriate analysis methods and suitable synthesis procedures. On the other hand, benefits of using GWs instead of conventional structures are required to be more clearly evidenced with high-performance GW components and proper comparatives with conventional structures. This thesis introduces several efficient analysis methods, models, and synthesis techniques that will allow engineers without significant background in GWs to straightforwardly implement GW devices. In addition, several high-performance narrow-band filters operating at Ka-band and V-band, as well as a rigorous comparative with rectangular waveguide topology, are presented. / Esta tesis aborda problemas actuales en el análisis y diseño de componentes pasivos en las bandas de onda milimétrica y Terahercios (THz). Se presentan nuevas técnicas de análisis y modelado de estructuras complejas, procedimientos de diseño, e implementación práctica de dispositivos pasivos avanzados. La primera parte de la tesis se dedica a componentes pasivos de THz. Actualmente no se disponen de guías de onda adecuadas a THz debido a que ambos, metales y dieléctricos, introducen grandes pérdidas. En consecuencia, no es adecuado escalar las estructuras metálicas cerradas usadas en microondas, ni las guías dieléctricas usadas a frecuencias ópticas. Entre un gran número de recientes propuestas, la Single Wire Waveguide (SWW) destaca por su baja atenuación y casi nula dispersión. No obstante, como guía superficial, la SWW presenta difícil excitación y radiación en curvas. El uso de un recubrimiento dieléctrico, creando la Dielecric-Coated Single Wire Waveguide (DCSWW), alivia estos inconvenientes, pero las ventajas anteriores se pierden y nuevos problemas aparecen. Hasta la fecha, no se han encontrado soluciones adecuadas para la radiación en curvas de la SWW. Además, se echa en falta una caracterización rigurosa de ambas guías. Esta tesis presenta, por primera vez, un análisis modal completo de SWW y DCSWW, adecuado a la banda de THz. Este análisis es aplicado posteriormente para evitar el problema de la radiación en curvas. Se presentan y validan experimentalmente diversas estructuras y procedimientos de diseño. La segunda parte de la tesis abarca componentes pasivos de ondas milimétricas. Actualmente, estos componentes sufren una importante degradación de su respuesta debido a que resulta difícil asegurar contacto metálico y alineamiento adecuados para la operación a longitudes de onda tan pequeñas. Además, la absorción dieléctrica incrementa notablemente a estas frecuencias. En consecuencia, tanto guías metálicas huecas como líneas de transmisión planares convencionales presentan gran atenuación, siendo necesario considerar topologías alternativas. Las Gap Waveguides (GWs), basadas en una estructura periódica que introduce un efecto de Electromagnetic Bandgap, resultan muy adecuadas puesto que no requieren contacto entre partes metálicas y evitan las pérdidas en dieléctricos. No obstante, a pesar del potencial de las GWs, varias barreras impiden la consolidación y uso universal de esta tecnología. Por una parte, la compleja topología de las GWs dificulta el proceso de diseño dado que las simulaciones de onda completa consumen mucho tiempo y no existen actualmente métodos de análisis y diseño apropiados. Por otra parte, es necesario evidenciar el beneficio de usar GWs mediante dispositivos GW de altas prestaciones y comparativas adecuadas con estructuras convencionales. Esta tesis presenta diversos métodos de análisis eficientes, modelos, y técnicas de diseño que permitirán la síntesis de dispositivos GW sin necesidad de un conocimiento profundo de esta tecnología. Asimismo, se presentan varios filtros de banda estrecha operando en las bandas Ka y V con altas prestaciones, así como una comparativa rigurosa con la guía rectangular. / Aquesta tesi aborda problemes actuals en relació a l'anàlisi i disseny de components passius en les bandes d'ona mil·limètrica i Terahercis. Es presenten noves tècniques d'anàlisi i modelatge d'estructures complexes, procediments de disseny, i implementació pràctica de dispositius passius avançats. La primera part de la tesi es focalitza en components passius de THz. Actualment no es disposen de guies d'ona adequades a THz causa que tots dos, metalls i dielèctrics, introdueixen grans pèrdues. En conseqüència, no és adequat escalar les estructures metál·liques tancades usades en microones, ni les guies dielèctriques usades a freqüències òptiques. Entre un gran nombre de propostes recents, la Single Wire Waveguide (SWW) destaca per la seua baixa atenuació i quasi nul·la dispersió. No obstant això, com a guia superficial, la SWW presenta difícil excitació i radiació en corbes. L'ús d'un recobriment dielèctric, creant la Dielecric-Coated Single Wire Waveguide (DCSWW), alleuja aquests inconvenients, però els avantatges anteriors es perden i nous problemes apareixen. Fins a la data, no s'han trobat solucions adequades per a la radiació en corbes de la SWW. A més, es troba a faltar una caracterització rigorosa d'ambdues guies. Aquesta tesi presenta, per primera vegada, un anàlisi modal complet de SWW i DCSWW, adequat a la banda de THz. Aquest anàlisi és aplicat posteriorment per evitar el problema de la radiació en corbes. Es presenten i validen experimentalment diverses estructures i procediments de disseny. La segona part de la tesi es centra en components passius d'ones mil·limètriques. Actualment, aquests components pateixen una important degradació de la seua resposta a causa de que resulta difícil assegurar contacte metàl·lic i alineament adequats per a l'operació a longituds d'ona tan menudes. A més, l'absorció dielèctrica incrementa notablement a aquestes freqüències. En conseqüència, tant guies metàl·liques buides com línies de transmissió planars convencionals presenten gran atenuació, sent necessari considerar topologies alternatives. Les Gap Waveguides (GWs), basades en una estructura periòdica que introdueix un efecte de Electromagnetic Bandgap, resulten molt adequades ja que no requereixen contacte entre parts metàl·liques i eviten les pèrdues en dielèctrics. No obstant, tot i el potencial de les GWs, diverses barreres impedixen la consolidació i ús universal d'aquesta tecnologia. D'una banda, la complexa topologia de les GWs dificulta el procés de disseny atés que les simulacions d'ona completa consumeixen molt de temps i no existeixen actualment mètodes d'anàlisi i disseny apropiats. D'altra banda, és necessari evidenciar el benefici d'utilitzar GWs mitjançant dispositius GW d'altes prestacions i comparatives adequades amb estructures convencionals. Aquesta tesi presenta diversos mètodes d'anàlisi eficients, models, i tècniques de disseny que permetran la síntesi de dispositius GW sense necessitat d'un coneixement profund d'aquesta tecnologia. Així mateix, es presenten diversos filtres de banda estreta operant en les bandes Ka i V amb altes prestacions, així com una comparativa rigorosa amb la guia rectangular. / Berenguer Verdú, AJ. (2017). Analysis and design of efficient passive components for the millimeter-wave and THz bands [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84004

The content of this work was to carry out construction-technical survey of timber structures of the existing building in order to design an appropriate procedure for their reconstruction. The survey showed construction in an unsatisfactory to disrepair, so further work also includes the static calculation of new structures proposed instead of the current. Timber structure in the building has form of staircase, roof and ceiling construction. Newly designed the following types of stairs and roof trusses from which the lower belts are used as ceiling beams. The new proposal also includes possible roofing, roofing options, developed one of them. The work also includes drawings, bill of materials and cost estimate staircase structure and truss. Specialization in the field of civil engineering is represented by drawings of the new truss and passport (view of current state) whole object on parcel ST.74 / 1, land Tišnov (okr.Brno-venkov), the content of which was the basis for this work.

This research work concentrate on developing digital soil maps to support field based plant phenotyping research. We have developed soil organic matter content (OM), cation exchange capacity (CEC), natural soil drainage class, and tile drainage line maps using topographic indices and aerial imagery. Various prediction models (universal kriging, cubist, random forest, C5.0, artificial neural network, and multinomial logistic regression) were used to estimate the soil properties of interest.