Computational approaches and tools for modeling biomass pyrolysis

Thesis (Ph.D.)--University of Washington, 2016-08

Essays in International Finance and Macroeconomics

Thesis (Ph.D.)--University of Washington, 2016-08

Chitosan scaffold as an alternative adsorbent for the removal of hazardous food dyes from aqueous solutions

Hypothesis: The dye adsorption with chitosan is considered an eco-friendly alternative technology in relation to the existing water treatment technologies. However, the application of chitosan for dyes removal is limited, due to its low surface area and porosity. Then we prepared a chitosan scaffold with a megaporous structure as an alternative adsorbent to remove food dyes from solutions. Experiments: The chitosan scaffold was characterized by infrared spectroscopy, scanning electron microscopy and structural characteristics. The potential of chitosan scaffold to remove five food dyes from solutions was investigated by equilibrium isotherms and thermodynamic study. The scaffold–dyes interactions were elucidated, and desorption studies were carried out. Findings: The chitosan scaffold presented pore sizes from 50 to 200 lm, porosity of 92.2 ± 1.2% and specific surface area of 1135 ± 2 m2 g 1. The two-step Langmuir model was suitable to represent the equilibrium data. The adsorption was spontaneous, favorable, exothermic and enthalpy-controlled process. Electrostatic interactions occurred between chitosan scaffold and dyes. Desorption was possible with NaOH solution (0.10 mol L 1). The chitosan megaporous scaffold showed good structural characteristics and high adsorption capacities (788–3316 mg g 1).

Integrability for Relativistic Spin Networks

The evaluation of relativistic spin networks plays a fundamental role in the Barrett-Crane state sum model of Lorentzian quantum gravity in 4 dimensions. A relativistic spin network is a graph labelled by unitary irreducible representations of the Lorentz group appearing in the direct integral decomposition of the space of L^2 functions on three-dimensional hyperbolic space. To `evaluate' such a spin network we must do an integral; if this integral converges we say the spin network is `integrable'. Here we show that a large class of relativistic spin networks are integrable, including any whose underlying graph is the 4-simplex (the complete graph on 5 vertices). This proves a conjecture of Barrett and Crane, whose validity is required for the convergence of their state sum model.

La estructura familiar dibujada por los propios niños/as. Una aproximación al dibujo como mediador social en las relaciones sistémicas familiares

Con esta investigación se pretende analizar la idea de familia que tienen los niños/as en la actualidad y cómo la representan a través del dibujo infantil. El estudio ha sido realizado a partir de un muestreo realizado a niños/as de entre 4 y 6 años, extraído de tres escuelas, dos públicas y una privada en Granada (España). La investigación mantiene un carácter cualitativo. Para la realización del mismo hemos utilizado los siguientes procedimientos: recopilación de 100 dibujos, otras tantas entrevistas grabadas en audio, observación visual y notas de campo. Nos aseguramos así un seguimiento tanto del proceso creativo como de la propia opinión de los infantes. En la investigación, los niños/as mostraron plásticamente una idea de familia nuclear, de cuyos progenitores, el padre fue representado apenas participando en las tareas del hogar; mientras que la madre se representó asociada a las tareas domésticas y al cuidado de sus hijos. Sobre otras realidades familiares, en concreto la familia homosexual, carecen absolutamente de referencias.

Análisis y simulación de un rectificador trifásico controlado Active Front End (AFE)

Este artículo presenta un resultado de investigación financiado con recursos propios en el que se expone un modelo en espacio de estados de un rectificador trifásico controlado active front end. Utilizando este modelo se deriva una ley de control orientado al voltaje (VOC), enfocado en el comportamiento como carga resistiva, factor de potencia unitario, el cual es probado mediante simulación usando el Toolbox SimPowerSystem en Simulink de Matlab®.

Propuesta de un modelo de evaluación bidimensional en Moodle

El modelo de evaluación bidimensional MEB en la educación superior, propuesto en este trabajo mide el conocimiento de estudiantes versus grado de certeza. El análisis de estas dos dimensiones permite al profesor determinar áreas de conocimiento a profundizar con sus estudiantes. La investigación fue descriptiva y correlacional, fueron aplicados métodos científico e inductivo. Las técnicas utilizadas fueron cuestionarios y análisis estadístico y recursos técnicos fueron: sistema de gestión de aprendizaje Moodle, software para análisis matemático MATLAB, EXCEL, laboratorios de la Facultad de Informática y Electrónica (FIE) de la Escuela Superior Politécnica de Chimborazo (ESPOCH), institución donde se llevó a cabo el estudio. El MEB propone la aplicación de cuestionarios de selección múltiple con el mecanismo CBM (Certainty based marking - Marcado basado en la certeza), sobre un aula virtual creada en el sistema Moodle. CBM permite medir por cada pregunta de un cuestionario las dimensiones conocimiento y certeza.

An identification procedure of multi-input Wiener models for the distortion analysis of nonlinear circuits

In this contribution, a system identification procedure of a two-input Wiener model suitable for the analysis of the disturbance behavior of integrated nonlinear circuits is presented. The identified block model is comprised of two linear dynamic and one static nonlinear block, which are determined using an parameterized approach. In order to characterize the linear blocks, an correlation analysis using a white noise input in combination with a model reduction scheme is adopted. After having characterized the linear blocks, from the output spectrum under single tone excitation at each input a linear set of equations will be set up, whose solution gives the coefficients of the nonlinear block. By this data based black box approach, the distortion behavior of a nonlinear circuit under the influence of an interfering signal at an arbitrary input port can be determined. Such an interfering signal can be, for example, an electromagnetic interference signal which conductively couples into the port of consideration. © 2011 Author(s).

Fast-Track Authority and International Trade Negotiations

Fast Track Authority (FTA) is the institutional procedure in the Unites States whereby Congress grants to the President the power to negotiate international trade agreements. Under FTA, Congress can only approve or reject negotiated trade deals, with no possibility of amending them. In this paper, we examine the determinants of FTA voting decisions and the implications of this institutional procedure for trade negotiations. We describe a simple two-country trade model, in which industries are unevenly distributed across con- stituencies. In the foreign country, trade negotiating authority is delegated to the executive, while in the home country Congress can retain the power to amend trade agreements. We show that legislators’ FTA voting behavior depends on the trade policy interests of their own constituencies as well as those of the majority of Congress. Empirical analysis of the determinants of all FTA votes between 1974 (when fast track was first introduced) and 2002 (when it was last granted) provides strong support for the predictions of our model.

Shaping the Dicot Fruit: Molecular and Genomic Approaches to Fruit Development

The fruit is one of the most complex and important structures produced by flowering plants, and understanding the development and maturation process of fruits in different angiosperm species with diverse fruit structures is of immense interest. In the work presented here, molecular genetics and genomic analysis are used to explore the processes that form the fruit in two species: The model organism Arabidopsis and the diploid strawberry Fragaria vesca. One important basic question concerns the molecular genetic basis of fruit patterning. A long-standing model of Arabidopsis fruit (the gynoecium) patterning holds that auxin produced at the apex diffuses downward, forming a gradient that provides apical-basal positional information to specify different tissue types along the gynoecium’s length. The proposed gradient, however, has never been observed and the model appears inconsistent with a number of observations. I present a new, alternative model, wherein auxin acts to establish the adaxial-abaxial domains of the carpel primordia, which then ensures proper development of the final gynoecium. A second project utilizes genomics to identify genes that regulate fruit color by analyzing the genome sequences of Fragaria vesca, a species of wild strawberry. Shared and distinct SNPs among three F. vesca accessions were identified, providing a foundation for locating candidate mutations underlying phenotypic variations among different F. vesca accessions. Through systematic analysis of relevant SNP variants, a candidate SNP in FveMYB10 was identified that may underlie the fruit color in the yellow-fruited accessions, which was subsequently confirmed by functional assays. Our lab has previously generated extensive RNA-sequencing data that depict genome-scale gene expression profiles in F. vesca fruit and flower tissues at different developmental stages. To enhance the accessibility of this dataset, the web-based eFP software was adapted for this dataset, allowing visualization of gene expression in any tissues by user-initiated queries. Together, this thesis work proposes a well-supported new model of fruit patterning in Arabidopsis and provides further resources for F. vesca, including genome-wide variant lists and the ability to visualize gene expression. This work will facilitate future work linking traits of economic importance to specific genes and gaining novel insights into fruit patterning and development.

Diseño de un sistema de control de costos para el proceso de construcción de vivienda popular

El objetivo,para el desarrollo de este proyecto de graduación, es establecer un control de costos en las viviendas de interés social que se desarrollan en el Ecuador, a nivel de proyectos, ejecutados por empresas constructoras o contratistas. Se tomarán datos de la ejecución en campo de viviendas de 42 m2 de construcción, en la comunidad de Macas provincia del Cañar. Se verificarán materiales reales, rendimiento de mano de obra reales y rendimientos de equipo y transporte reales, con el afán de determinar el costo real de la obra. Todos estos datos se registrarán en el modelo desarrollado con lo que se comparará lo ejecutado contra lo programado. En el caso de existir un desfase entre estos dos parámetros, el modelo proyectará un nuevo presupuesto, asegurándose de que los gastos no excedan el financiamiento autorizado para el proyecto. El modelo almacenará datos de rendimientos de mano de obra, precios de materiales, equipos y transporte. Esto permitirá plantear presupuestos para futuros proyectos con precios cada vez más cercanos a los reales en la ejecución del proyecto, ayudando, de manera permanente, a instituciones gubernamentales profesionales de la construcción dedicadas a la proyección de viviendas.

Simultaneous estimation of the nutritional contribution of fish meal, soy protein isolate and corn gluten to the growth of Pacific white shrimp (Litopenaeus vannamei) using dual stable isotope analysis

The nutritional contribution of the dietary nitrogen, carbon and total dry matter supplied by fish meal (FM), soy protein isolate (SP) and corn gluten (CG) to the growth of Pacific white shrimp Litopenaeus vannamei was assessed by means of isotopic analyses. As SP and CG are ingredients derived from plants having different photosynthetic pathways which imprint specific carbon isotope values to plant tissues, their isotopic values were contrasting. FM is isotopically different to these plant meals with regards to both, carbon and nitrogen. Such natural isotopic differences were used to design experimental diets having contrasting isotopic signatures. Seven isoproteic (36% crude protein), isoenergetic (4.7 kcal g−1) diets were formulated; three diets consisted in isotopic controls manufactured with only one main ingredient supplying dietary nitrogen and carbon: 100% FM (diet 100F), 100% SP (diet 100S) and 100% CG (diet 100G). Four more diets were formulated with varying mixtures of these three ingredients, one included 33% of each ingredient on a dietary nitrogen basis (diet 33FSG) and the other three included a proportion 50:25:25 for each of the three ingredients (diets 50FSG, 50SGF and 50GFS). At the end of the bioassay there were no significant differences in growth rate in shrimps fed on the four mixed diets and diet 100F (k=0.215–0.224). Growth rates were significantly lower (k=0.163–0.201) in shrimps grown on diets containing only plant meals. Carbon and nitrogen stable isotope values (δ13C and δ15N) were measured in experimental diets and shrimp muscle tissue and results were incorporated into a three-source, two-isotope mixing model. The relative contributions of dietary nitrogen, carbon and total dry matter from FM, SP and CG to growth were statistically similar to the proportions established in most of the diets after correcting for the apparent digestibility coefficients of the ingredients. Dietary nitrogen available in diet 33FSG was incorporated in muscle tissue at proportions representing 24, 35 and 41% of the respective ingredients. Diet 50GSF contributed significantly higher amounts of dietary nitrogen from CG than from FM. When the level of dietary nitrogen derived from FM was increased in diet 50FSG, nutrient contributions were more comparable to the available dietary proportions as there was an incorporation of 44, 29 and 27% from FM, SP and CG, respectively. Nutritional contributions from SP were very consistent to the dietary proportions established in the experimental diets.

Proposta de modelagem de qualidade ambiental em áreas metropolitanas, por meio de dados de sensoriamento remoto

Tese (doutorado)—Universidade de Brasília, Instituto de Geociências, Pós-Graduação em Geociências Aplicadas, 2016.

Slow passage through thresholds in quantum dot lasers

A turn on of a quantum dot (QD) semiconductor laser simultaneously operating at the ground state (GS) and excited state (ES) is investigated both experimentally and theoretically. We find experimentally that the slow passage through the two successive laser thresholds may lead to significant delays in the GS and ES turn ons. The difference between the turn-on times is measured as a function of the pump rate of change and reveals no clear power law. This has motivated a detailed analysis of rate equations appropriate for two-state lasing QD lasers. We find that the effective time of the GS turn on follows an -1/2 power law provided that the rate of change is not too small. The effective time of the ES transition follows an -1 power law, but its first order correction in ln is numerically significant. The two turn ons result from different physical mechanisms. The delay of the GS transition strongly depends on the slow growth of the dot population, whereas the ES transition only depends on the time needed to leave a repellent steady state.

Effects of solid poly (ethylene glycols) addition to the solutions of aniline or N,N-dimethylaniline with water:experimental measurements and modelling

In this work, the liquid-liquid and solid-liquid phase behaviour of ten aqueous pseudo-binary and three binary systems containing polyethylene glycol (PEG) 2050, polyethylene glycol 35000, aniline, N,N-dimethylaniline and water, in the temperature range 298.15-350.15 K and at ambient pressure of 0.1 MPa, was studied. The obtained temperature-composition phase diagrams showed that the only functional co-solvent was PEG2050 for aniline in water, while PEG35000 even showed a clear anti-solvent effect in the N,N-dimethylaniline aqueous system. The experimental solid-liquid equilibria (SLE) data have been correlated by the non-random two-liquid (NRTL) model, and the correlation results are in accordance with the experimental results.