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Augmented Lagrangian method for a total variation-based model for demodulating phase discontinuities

RICARDO LEGARDA SAENZ CARLOS FRANCISCO BRITO LOEZA (2020)

In this work, we reformulate the method presented in App. Opt. 53:2297 (2014) as a constrained minimization problem using the augmented Lagrangian method. First we introduce the new method and then describe the numerical solution, which results in a simple algorithm. Numerical experiments with both synthetic and real fringe patterns show the accuracy and simplicity of the resulting algorithm.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA INGENIERÍA Y TECNOLOGÍA Phase demodulation Fringe analysis Inverse problems Variational models

A mean curvature regularized based model for demodulating phase maps from fringe patterns

CARLOS FRANCISCO BRITO LOEZA RICARDO LEGARDA SAENZ ARTURO ESPINOSA ROMERO ANABEL MARTIN GONZALEZ (2018)

We introduce a variational method for demodulating phase maps from fringe patterns. This new method is based on the mean curvature of the level sets of the phase surface that is used for regularization. The performance of the method is illustrated with both synthetic and real data.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA INGENIERÍA Y TECNOLOGÍA Fringe analysis Interferometry High-order regularization Variational models

CFD Analysis of Bed Textural Characteristics on TBR Behavior: Kinetics, Scaling-up, Multiscale Analysis and Wall Effects

JOSE SEBASTIAN URIBE LOPEZ MARIO EDGAR CORDERO SANCHEZ LUIS GUADALUPE ZARATE LOPEZ José Javier Valencia López REYNA NATIVIDAD RANGEL (2018)

A simulation of a trickle bed reactor aided by computational fluid dynamics was implemented. With a Eulerian approach, geometrical characteristics were explicitly considered and two simultaneous heterogeneous reactions were included, hydrodesulphurization (HDS) and hydrodenitrogenation (HDN). This was performed in order to achieve the following: (1) attain further insight into a proper scaling‐up procedure to be able to obtain the same hydrodynamics and kinetics behavior in two reactors of different length and diameter scales; (2) develop a multiscale analysis regarding the communication of information between scales through the construction of a porous microstructure model from which the geometrical information of the microscale is captured by the effective transport coefficients (which affect the overall reactor behavior); (3) investigate the effect of operation conditions variations on hydrodynamics and kinetics; (4) and assess the deviations and further differences observed from average to punctual conversion values and the assumptions from kinetic literature models through a preliminary multiscale analysis. The CFD results were validated against experimental pressure drops data as well as HDS and HDN conversions theoretical data. An excellent agreement was found. The model produces a significant improvement in hydrodynamic parameters prediction, achieving 5 times better accuracy in predicting pressure drops and 50% improvement in holdup prediction. The fully coupled model predicts HDS conversion with 96% accuracy and HDN conversion with 94% accuracy. Results suggest that the best way to obtain similar kinetic and hydrodynamic behavior in TBRs with different length and diameter length scales is by equaling the liquid holdup (εγ) or the mass velocities (L‐G).

Article

TBR CFD simulation catalyst geometry bed porosity scale-up process Kinetics multiscale analysis INGENIERÍA Y TECNOLOGÍA

Análisis modal de brackets metálicos para arneses eléctricos utilizando NX Nastran

Indira Cruz Realeño (2021)

La principal función de un bracket metálico es dar soporte y sujeción a los arneses eléctricos vehiculares, por lo que su desempeño mecánico deberá cumplir con los requerimientos mínimos para evitar rechinido o fallas debido a resonancia. El objetivo de este estudio es determinar la combinación de parámetros de entrada al software NX Nastran, como es el tamaño de elemento, el orden del elemento, el número de elementos a través del espesor del bracket, así como el tipo de elemento de conexión 1D, que permitan obtener la frecuencia natural de los brackets y que aproximen el resultado a una diferencia no mayor al 10% con respecto a los resultados proporcionados por un Centro Especializado de Validación. Las combinaciones de los parámetros de control que mejor aproximen a la validación oficial se obtienen a partir de un diseño de experimentos.

The objective of this study is to determine the combination of input parameters to the NX Nastran software such as the size of the element, the order of the element, the number of elements through the thickness of the bracket, as well as the type of 1D connection element that allow obtaining the natural frequency of the brackets and that approximate the result to a difference of no greater than 10% to the results provided by an Specialized Validation Center. The combinations of the control parameters that best approximate to official validation are obtained from a design of experiments.

Master thesis

CAE FEM Análisis modal NX Computer engineering Simulation Modal analysis INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE LOS ORDENADORES SIMULACIÓN SIMULACIÓN

Internal ballistics of polygonal and grooved barrels: A comparative study

LUIS ADRIAN ZUÑIGA AVILES USIEL SANDINO SILVA RIVERA ADRIANA HERLINDA VILCHIS GONZALEZ PEDRO ALEJANDRO TAMAYO MEZA WILBERT DAVID WONG ANGEL (2021)

As a parameter important ballistic, the research about polygonal and grooved barrels’ behavior has not been widely carried out. The pressures, velocities, stresses, deformations, and strains generated by the firing of 9 mm × 19 mm ammunition in weapons with polygonal barrels are analyzed numerically and experimentally, compared with those generated in pistols with grooved barrels. The Finite Element Method with equal boundary and loading conditions was used in both types of guns, specifying the actual materials of the projectile and the barrels. Subsequently, experimental tests were carried out on various weapons with 9 mm ammunitions of 115, 122, and 124 gr. The results show that the 9 mm bullet fired in a polygonal barrel undergoes a maximum deformation towards its exterior of 0.178 mm and interior of 0.158 mm, with stress up to 295.85 MPa. Compared with 0.025 mm maximum external deformation and 0.112 mm internal deformation of 9 mm projectiles fired in a grooved barrel, with stress up to 269.79 MPa. The deformation in the polygonal barrel is in a greater area, but the rifling impression left is less deep, making its identification more difficult. Although there are differences in the stresses and strains obtained, similar velocity and pressure parameters are achieved in the two types of barrels. This has application in the development and standardization of new kinds of barrels and weapons.

As a parameter important ballistic, the research about polygonal and grooved barrels’ behavior has not been widely carried out. The pressures, velocities, stresses, deformations, and strains generated by the firing of 9 mm × 19 mm ammunition in weapons with polygonal barrels are analyzed numerically and experimentally, compared with those generated in pistols with grooved barrels. The Finite Element Method with equal boundary and loading conditions was used in both types of guns, specifying the actual materials of the projectile and the barrels. Subsequently, experimental tests were carried out on various weapons with 9 mm ammunitions of 115, 122, and 124 gr. The results show that the 9 mm bullet fired in a polygonal barrel undergoes a maximum deformation towards its exterior of 0.178 mm and interior of 0.158 mm, with stress up to 295.85 MPa. Compared with 0.025 mm maximum external deformation and 0.112 mm internal deformation of 9 mm projectiles fired in a grooved barrel, with stress up to 269.79 MPa. The deformation in the polygonal barrel is in a greater area, but the rifling impression left is less deep, making its identification more difficult. Although there are differences in the stresses and strains obtained, similar velocity and pressure parameters are achieved in the two types of barrels. This has application in the development and standardization of new kinds of barrels and weapons.

Article

Polygonal rifling groove rifling impression on fired bullets transient analysis INGENIERÍA Y TECNOLOGÍA

Obtención del grado de degradación de un suelo por actividades agrícolas en la zona aguacatera michoacana

YOSINIA MARTINEZ MENDEZ (2015)

204 páginas. Maestría en Ciencias e Ingeniería Ambientales.

Consejo Nacional de Ciencia y Tecnología (México).

En este trabajo se presenta el estudio del avance de la degradación a causa de las malas prácticas agrícolas que se realizan y el uso excesivo de agroquímicos de algunos suelos de los municipios que abarcan una zona aguacatera en el estado de Michoacán y que está afectando la producción del aguacate. Para ello se presentan resultados de la caracterización física y química del suelo de una zona aguacatera en el cual se realizan actividades agrícolas convencionales sin control, asimismo un suelo con actividad agrícola orgánica y un suelo con vegetación original que funcionará como testigo. Se ha obtenido la concentración de metales totales nutrientes y contaminantes en el suelo degradado, en el orgánico y en el testigo, asimismo, se ha efectuado un estudio de aniones importantes como los fosfatos, nitrógeno total y orgánico.

Master thesis

Soil degradation. Soils--Analysis. Degradación del suelo. Cultivos y suelos. S623 S591 INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS INGENIERÍA Y TECNOLOGÍA DEL MEDIO AMBIENTE INGENIERÍA DE LA CONTAMINACIÓN

Natural Disasters and Economic Growth: a synthesis of empirical evidence

Fernando Antonio Ignacio González (2021)

Natural disasters pose a serious threat globally and, in the future, their frequency and severity are expected to increase due to climate change. Empirical evidence has reported conflicting results in terms of the impact of disasters on economic growth. In this context, the present work seeks to synthesize the recent empirical evidence related to this topic. More than 650 estimates, from studies published in the last five years (2015-2020), are used. Meta-analysis and meta-regression techniques are employed. The review includes three sources (Scopus, Science Direct, and Google Scholar). The results identified the existence of a negative and significant combined effect (-0.015). Developing countries are especially vulnerable to disasters. The negative impact is greater for disasters that occurred in the last decade -in relation to previous disasters-. These findings constitute a call for attention in favor of mitigation and adaptation policies.

Article

Artículo

disasters growth GDP meta-analysis meta-regression desastres crecimiento PIB meta-análisis meta-regresión CIENCIAS SOCIALES CIENCIAS SOCIALES

Electrochemical and microstructural analysis of a modified gas diffusion layer for a PEM water electrolyzer

Julio César Cruz Arguello GLISERIO ROMELI BARBOSA POOL Beatriz Escobar Morales zakaryaa zarhri DANNA LIZETH TREJO ARROYO BLANDY BERENICE PAMPLONA SOLIS LEOPOLDO GOMEZ BARBA (2020)

Water electrolysis is an electrochemical process capable of producing high-purity hydrogen (H2 ≈ 100%). However, due to high anodic operating potentials, which are greater than 1.8 V in acidic media, they tend to degrade the components that are currently designed. One of the main components is the gas diffusion layer (GDL) of a proton exchange membrane water electrolyzer (PEMWE). A commonly used carbon GDL is coal. However, the acid medium increases the potential to 1.4 V, which causes the GDL to become oxidized and degrade; the above result is due to the generation of carbon products that poison the electrode and the blocking of active sites, all of which decrease the performance of the cell. In this work, the results of a morphological study on a modified titanium porous matrix are presented. The analysis includes the determination of the microstructural influence on mass transport through numerical simulation and statistical electrochemical characterization techniques. Two different microstructural attacks are performed to modify the porous matrix. These attacks consist of an acidic mixture of 17 and 27% v/v HCl/H2SO4 and an attack by a 0.1 M oxalic acid solution; these attacks were performed at different times. Afterward, the GDLs were characterized by scanning electron microscopy (SEM) at different magnifications to determine significant microstructural differences between the three matrices (the two that are modified and the one without modification) and their stochastic reconstruction. Subsequently, a surface area characterization is performed by the BET absorption technique to calculate the porosity of the different matrices.

Article

WATER ELECTROLYSIS MICROSTRUCTURAL ANALYSIS GAS DIFFUSION LAYER POROUS MATRIX MICROSTRUCTURAL ATTACK CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO HIDROLOGÍA CALIDAD DE LAS AGUAS CALIDAD DE LAS AGUAS