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Vadose zone hydraulic conductivity monitoring by using an arduino data acquisition system


In this work the development of a continuous monitoring system for the hydraulic conductivity is presented. The system uses the measurement of temperatures in geological materials at different depths to calculate the wáter flux rates by using analytical solutions for the Stallman´s heat and fluid transport equation. Data from sensors are filtered and phase and amplitude information is extracted by using Digital Signal Processing techniques, such as DHR inside MATLAB environment. A column test was developed to evaluate the system performance and its results were compared against real infiltration data. Initial result shows a good performance (r- RSME = 0.08). After improvements, the system could be installed in the field to monitor water flux rates and hydraulic conductivity in intermittent rivers and areas considered as a recharge zones to study and quantify infiltration volumes.

Producción Científica de la Universidad Autónoma de Zacatecas UAZ

Conference paper

INGENIERÍA Y TECNOLOGÍA Dynamic Harmonic Regression (DHR) Hydraulic conductivity Stallman equation

Barotropic FRW cosmologies with a Dirac-like parameter


"Using the known connection between Schroedinger-like equations and Dirac-like equations in the supersymmetric context, we discuss an extension of FRW barotropic cosmologies in which a Dirac mass-like parameter is introduced. New Hubble cosmological parameters HK(n) depending on the Dirac-like parameter are plotted and compared with the standard Hubble case H0(n). The new HK(n) are complex quantities. The imaginary part is a supersymmetric way of introducing dissipation and instabilities in the barotropic FRW hydrodynamics."



Classical harmonic oscillator with Dirac-like parameters and possible applications


"We obtain a class of parametric oscillation modes that we call K-modes with damping and absorption that are connected to the classical harmonic oscillator modes through the “supersymmetric” one-dimensional matrix procedure similar to relationships of the same type between Dirac and Schr¨odinger equations in particle physics. When a single coupling parameter, denoted by K, is used, it characterizes both the damping and the dissipative features of thesemodes. Generalizations to severalK parameters are also possible and lead to analytical results. If the problem is passed to the physical optics (and/or acoustics) context by switching from the oscillator equation to the corresponding Helmholtz equation, one may hope to detect the K-modes as waveguide modes of specially designed waveguides and/or cavities."


Quantum-mechanics Supersymmetry Equation Diffraction Modes Light CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA

Modified method of hyperspheres: tracing homotopic bounded paths in nonlinear circuits


The equations describing the behavior of a electronic circuit are nonlinear due to nonlinear

elements and the DC analysis is the first step for analyzing a nonlinear circuit and also to

find the solution, or solutions, of the system of equations. Methods like Newton Raphson

algorithm present disadvantages to solve nonlinear problems besides are not capable to

find multiple solutions. To overcome above problems the homotopy methods can locate

multiple solutions for a system of equations; however homotopy methods convergence

depends of the starting point, the continuous methods and nonlinearities. The homotopy

formulation require suitable path tracking techniques to accurately trace the homotopy

curve, the algorithm to path-tracking used in this work is the spherical algorithm because

it is geometrically clear and this characteristic can facilitate its programming. However

during programming hyperspheres method there were some problems as reversion of the

path on the curve and slow for tracing. In this thesis, two proposed methodologies are used

to solve the above problems, the first proposed methodology is based in calculating the

normal vector to the curve for detecting the problem of reversion then the methodology

is used to avoid the problem of reversion. The second methodology is achieved during the

tracing of the homotopy curve to reduce the number of iterations and the computational

time. Both strategies are implemented and programmed for the hyperspheres method;

also several case studies are solved, and we found satisfactory results for the path tracking


Doctoral thesis

Homotopy method Nonlinear Equation nonlinear Continuation algorithm CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA

Complete gradient refractive index lens schematic human eye model


A new theoretical schematic model of the human eye is introduced. The new

model considers that the human eye crystalline is a gradient index lens composed

by two oblate half spheroids of different heights. By modifying the spherically

symmetric Luneburg model for a gradient index lens, we created a model for the

anterior and posterior half spheroids matching the corresponding geometric and

gradient index boundary conditions at the plane of fusion of the spheroids. We

tested the imaging capabilities of our model and found that it is more realistic

compared with those reported in the literature concluding that the gradient index

is dynamic and cannot be modeled by one single explicit equation.

Doctoral thesis

Ray equation Spherical luneburg lens Human eye Optical system Schematic eye CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA

Propiedades físicas y evolución de singularidades ópticas

Saul Isaias De los Santos Garcia (2017)

Al analizar la propagación de campos ópticos es posible detectar alto contenido energético localizado en pequeñas regiones del espacio, conocidas como regiones focales o causticas (RF). Estas se generan en donde las trayectorias del campo óptico convergen mediante un proceso de compresión o confinamiento espacial del frente de onda. Estos procesos de compresión pueden ser inducidos físicamente en el campo óptico por alguna componente óptica por ejemplo una lente o una curva rendija con una determinada curvatura, en este caso el campo óptico es focalizado y la geometría de su región focal es definida por la envolvente de centros de curvatura de la condición de frontera [1]. En el contexto de la óptica contemporánea se han realizado investigaciones sobre los mecanismos de generación de regiones focales así como la síntesis de diversos procesos ópticos asociados a las propiedades físicas de las regiones focales, como un ejemplo se encuentran procesos de vorticidad, bifurcación, corrimientos de fase [2, 3].

Para describir algunos de los efectos en el campo óptico con una región focal (RF) presente, se debe entender que este es generado a través de un proceso no-lineal, debido a que el campo óptico emergente de un punto en la condición de frontera (transmitancia), interacciona con el campo óptico de los puntos adyacentes de esta misma. De esta manera, el campo óptico experimenta compresión generando cambios en su función de amplitud y también en su función de fase dando lugar a procesos de autorregulados los cuales se manifiestan en los cambios de la dirección de propagación

del campo óptico. Cuando este proceso es generado por el paso de un campo óptico a través de una lente de curvatura constante, el proceso de compresión es el mismo para el campo emergente de cualquier punto de la lente siguiendo el principio de Huygens [4], siendo un punto la región focal para este caso. Sin embargo esto cambia cuando la geometría del elemento óptico es irregular, por ejemplo una rendija de función de curvatura monótonamente creciente, en este sistema óptico la compresión que experimenta el campo emergente de un punto en la rendija o condición de frontera será distinta dado que la función de curvatura varía de manera distinta en cada punto.

Doctoral thesis

Optical singularities Differential Geometry Tunable spatial filtering in fields Helmholtz equation CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA OPTICA FÍSICA

Reversible watermarking scheme with watermark and signal robustness for audio

Alejandra Menendez-Ortiz (2017)

In recent years, Internet use has increased the unauthorized distribution of multimedia

content and digital watermarking is a means to protect these contents from illegal

actions. However, conventional watermarking produces distortions to the watermarked

signals that cannot be counteracted, which are not acceptable for applications in the

medical or military field. Reversible watermarking schemes (RWS) allow to counteract

such distortions; although they are fragile, which means that any modification to the

watermarked signals will cause the loss of the embedded watermarks as well as the

original signal.

In this doctoral research, a reversible watermarking scheme with watermark and

signal robustness is proposed. It is a contribution to the state of the art because

there are no such schemes in the literature. A framework is proposed to address

this problem, that was validated through experimental results with images and audio

signals, and it is an abstract construction to solve the research problem. It was assumed

that since the framework proved to be effective for images, it could be followed in the

same way to propose a solution for audio signals.

The framework consists of two stages, namely a fragile reversible one and a selfrecovery

one. The fragile reversible stage allows the insertion of the watermark and

the self-recovery one inserts control information that allows the restoration after the

watermarked signals have been attacked with content replacement. To implement the

framework for audio signals, a reversible watermarking scheme and a self-recovery

scheme had to be proposed. The self-recovery scheme is a contribution to the state of

the art because, to the best of our knowledge, the scheme proposed is the first effort

for this type of media.

The reversible watermarking scheme for audio signals uses the auditory masking

properties of the signals to determine the frequencies where embedding of the watermark

will cause unnoticeable distortions. Moreover, the strategy from the reversible

watermarking scheme proposed was also included in the self-recovery scheme proposed,

and it allowed the insertion of the control information that was required for

perfect restoration of the signals after content replacement was applied. With perfect

restoration, the framework could be completed and tested for audio signals.

En años recientes, el uso de Internet ha incrementado la distribución no autorizada de

contenido multimedia y las marcas de agua digitales han sido utilizadas para proteger

estos contenidos de acciones ilegales. Sin embargo, los esquemas convencionales

producen distorsiones sobre las señales marcadas que no pueden ser contrarrestadas,

lo cual no es aceptable para aplicaciones en los campos médicos y militares. Los

esquemas de marcas de agua reversibles (RWS, por sus siglas en inglés) permiten

contrarestar estas distortiones, aunque son frágiles, lo que significa que cualquier

modificación a las señales marcadas causará la pérdida de las marcas insertadas así

como de las señales originales.

En esta investigación doctoral, se propone un esquema reversible de marcas de

agua con robustez de la marca y de la señal. Es una contribución al estado del arte

porque tales esquemas no existen en la literatura. Se propone un marco conceptual

para abordar el problema, éste fue validado a través de resultados experimentales con

imágenes y señales de audio, y éste es una abstracción para resolver el problema de

investigación. Se partió de la suposición que, dado que el marco conceptual demostró

ser efectivo para imágenes, éste podría utilizarse de la misma manera para una solución

en señales de audio.

El marco conceptual consiste en dos etapas, una frágil reversible y otra autorecuperable;

la etapa frágil reversible permite insertar la marca de agua y la etapa autorecuperable

inserta información de control que permite la restauración después que las

señales marcadas han sido atacadas con reemplazo de contenido. Para implementar el

marco para señales de audio, un esquema reversible de marcas agua y un esquema

auto-recuperable para señales de audio tuvieron que ser propuestos. El esquema

auto-recuperable es una contribución al estado del arte, dado que éste es el primer

esquema de este tipo para señales de audio.

El esquema reversible de marcas de agua para señales de audio utiliza las propiedades

de enmascaramiento auditivo para determinar las frecuencias donde la inserción de

la marca produce distorsiones que no son notorias. Aún más, la estrategia usada

por el esquema reversible de marcas de agua también fue incluida en el esquema

auto-recuperable propuesto, misma que permitió la inserción de la información de

control requerida para la restauración perfecta de las señales después que el ataque de

reemplazo de contenido.

Doctoral thesis

Optical singularities Differential Geometry Tunable spatial filtering in fields Helmholtz equation INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE LOS ORDENADORES INTELIGENCIA ARTIFICIAL

A rapid method for interfacial tension calculation between rock plug and crude oil based on contact angles, application for EOR


"Interfacial tension and contact angle are two specific important parameters to take decisions for enhanced oil recovery, for instance, proper chemicals to use for surface tension reduction, expected wettability of solids, interaction between crude oil and rock. For this purpose, the article presents a method for easy calculation of the solid-liquid interfacial tension based on contact angle measurements applying Neumann's correlation and Young's equation. The main idea stands on the calculation of the rock parameters, like wettability, with known substances and extend these results to crude oils. It was possible, based on the results obtained, to establish a relationship between solid-liquid interfacial tension and contact angle for the crude oil – rock system, which can definitively be used for the calculation of interfacial tension of any other fluid spread out on the same kind of rock. A linear regression was obtained with an accuracy as good as R2 = 0.9989. Viscosity as a function of contact angle could also be obtained for the studied crude oils in the same kind of rock."


Contact angle Interfacial tension Neumann's correlation Viscosity Young's equation INGENIERÍA Y TECNOLOGÍA INGENIERÍA Y TECNOLOGÍA

Traveling wave solutions for wave equations with two exponential nonlinearities

Stefan C. Mancas Haret Codratian Rosu MAXIMINO PEREZ MALDONADO (2018)

"We use a simple method that leads to the integrals involved in obtaining the travelling-wave solutions of wave equations with one and two exponential nonlinearities. When the constant term in the integrand is zero, implicit solutions in terms of hypergeometric functions are obtained, while when that term is nonzero, all the basic travelling-wave solutions of Liouville, Tzitzéica, and their variants, as as well sine/sinh-Gordon equations with important applications in the phenomenology of nonlinear physics and dynamical systems are found through a detailed study of the corresponding elliptic equations."


Dodd-Bullough Dodd-Bullough-Mikhailov Liouville Equation sine-Gordon sinh-Gordon Tzitzéica Weierstrass Function CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA FÍSICA

Supersymmetry of FRW barotropic cosmologies


"Barotropic FRW cosmologies are presented from the standpoint of nonrelativis-tic supersymmetry. First, we reduce the barotropic FRW system of differential equations to simple harmonic oscillator differential equations. Employing the fac-torization procedure, the solutions of the latter equations are divided into the two classes of bosonic (nonsingular) and fermionic (singular) cosmological solutions. We next introduce a coupling parameter denoted by K between the two classes of solutions and obtain barotropic cosmologies with dissipative features acting on the scale factors and spatial curvature of the universe. The K-extended FRW equations in comoving time are presented in explicit form in the low coupling regime. The standard barotropic FRW cosmologies correspond to the dissipa-tionless limit K = 0."


Supersymmetry FRW barotropic cosmology Riccati equation CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA