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Análisis estructural y termodinámico de aleaciones autofundentes NiCrSiB

OMAR GONZALEZ ORNELAS MAURICIO NANGO BLANCO DIEGO GERMAN ESPINOSA ARBELAEZ Juan Muñoz Saldaña Luis Alberto Cáceres Díaz (2021)

El uso de las aleaciones base níquel en la industria se ha vuelto cada vez más frecuente debido a sus excelentes propiedades termodinámicas, mecánicas y corrosivas. Su aplicación se ha extendido a la manufactura aditiva, recubrimientos, reparación de superficies, entre muchas otras. Sin embargo, la complejidad de los fenómenos termodinámicos en estos materiales en función de elementos aleantes y las transformaciones de fases hace necesario seguir comprendiendo su comportamiento. En este artículo se evalúan las partículas de polvo de una aleación base níquel autofundente compuesta por Cr, B, Si, Fe y C. Este análisis permite comprender con más detalle el papel del B y el Si al interactuar con la fase y-Ni, ya que generan fases eutécticas que disminuyen el punto de fusión. La estructura cristalina y estabilidad termodinámica se discuten en función del contenido de Fe, Cr, B y Si. El análisis termodinámico permitió identificar que el Fe y el Cr se ubican de manera sustitucional en la subred del Ni de la fase Ni3B a alta temperatura y esto causa un aumento en la constante de red de esta fase. Por su parte, la matriz Y-Ni acepta como elementos sustitucionales al Fe, Cr y Si y presenta transformación orden-desorden en función de la temperatura.

The use of Nickel based alloys on the industry has become more popular and useful because of the excellent thermodynamic, mechanical, and anti-corrosive properties. The use of this alloy has been extended to additive manufacturing, coatings, surface repairing and so many others. Nevertheless, the complexity from the thermodynamic phenomena on these materials, regarding to the alloy elements and the phase transformation makes it necessary to deepen the understanding of their behavior. In this article, the particles from a nickel self-fluxing based alloy powder that contains Cr, B, Si, Fe and C are evaluated. This analysis allows to understand in more detail the role of the B and Si with the interaction with the Y-Ni phase due to the generation of eutectic phases that diminished the fusion point. The crystal structure and thermodynamic stability are discussed in function to the content of Fe, Cr, B and Si. The thermodynamic analysis allows to identify that Fe and Cr locate in substitutional sites on the Ni sublattice from Ni3B phase at high temperature, and this cause an increment on lattice constant for this phase. The Y-Ni matrix allows Fe, Cr and Si as substitutional elements and exhibit an order-disorder transformation as a function of temperature.

Agradecimientos: A las instituciones CIATEQ, CIDESI y CINVESTAV, por haber favorecido con el uso de los equipos de los laboratorios nacionales CONMAD y CENAPROT para el desarrollo de este trabajo. También los autores agradecemos al programa de investigadores Cátedras CONACyT por el soporte científico brindado para el desarrollo de este trabajo.

Article

Aleación auto-fundente NiCrSiB Estructura cristalina Termodinámica computacional NiCrSiB self-fluxing alloy Crystal structure Computational thermodynamics INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE LA CONSTRUCCIÓN PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

Construcción y caracterización de un cristal artificial elástico

FILIBERTO RAMIREZ RAMIREZ (2021)

In order to achieve the main objective, a design of a supercell or basic cell consisting of an array of elastic units will be made. This supercell will be obtained from a locally periodic structure of coupled blocks, whose central block will be deformed; later, the one-dimensional elastic artificial crystal will be built, which will be characterized experimentally and understood from a strong mooring model. The locally proposed system consists of a set of vibrating bars, identical, coupled together, imitating a set of " defectsin a one-dimensional periodic network and with a periodic coupling. It is expected that the acoustic wave amplitudes of this system show similar characteristics to the wave functions of an electron strongly linked in an eective potential generated by a one-dimensional network of atoms. In the locally periodic system that we propose the vibrating elastic units will be coupled together by means of locally periodic rods; since, in these we can control the resonance frequencies and the same frequency of normal resonance. Furthermore, in these rods, the lower energy vibration modes can be isolated from the rest of the excited states. When the resonance frequency of the elastic unit (defect) is in the gap of the coupler (locally periodic rod) the wave amplitude will be located. To generate the emergence of a new band in the second torsion spectrum gap, from an originally periodic system, using the transfer matrix method for torsional waves, six elastic structures formed by 1, 2, 3 and up to 6 were designed. coupled supercell The neighboring levels of the emerging band is separated to a maximum distance of 100 Hz to facilitate its detection. This band is in the frequency range of 26450 to 26650 kHz.

En esta tesis se estudia experimentalmente las vibraciones de sistemas formados por arreglos de unidades elásticas acopladas, que pueden ser descritas por un modelo de enlace fuerte. Después de haber probado diversos métodos de acoplamiento mecánico, entre dos unidades elásticas, en el sistema se eligió como el más adecuado un subsistema localmente periódico que sería utilizado como acoplador de las mismas, entre sí. Los distintos sistemas elásticos fabricados, bajo diseño específico, se caracterizan por el método de espectroscopia acústica resonante (ARS) y se comparan los resultados experimentales con los obtenidos usando un modelo de enlace fuerte. El objetivo de esta tesis es diseñar y caracterizar un cristal artificial elástico unidimensional con propiedades espectrales de un cristal atómico. Para ello se diseñó primero una supercelda o celda básica unitaria apropiada. Esta supercelda se obtuvo a partir de una estructura localmente periódica de celdas elásticas simples idénticas, uno de cuyos bloques se deforman en longitud, por lo que le denominamos el defecto dentro de la estructura periódica o impureza (ver gura 4.1). Mediante la deformación de la celda simple es posible aislar los modos de vibración de la banda de transmisión y forzarlos a aparecer dentro de las brechas que aparecen en el sistema periódico original (ver figura 3.2). Esto origina que la amplitud de onda torsional se localice dando lugar a una fenomenología análoga a la de los cristales atómicos que son descritos a través de un modelo de enlace fuerte. Habiendo conseguido un diseño que presenta las características adecuadas, tanto para la realización del modelo, como de la medición experimental se construye y se caracteriza experimentalmente.

Doctoral thesis

Crystals. Elasticity. Spectroscopy. Spectrum Analysis--methods. Cristales. QD933 INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES

A classical simulation of nonlinear Jaynes–Cummings and Rabi models in photonic lattices

BLAS MANUEL RODRIGUEZ LARA FRANCISCO SOTO EGUIBAR ALEJANDRO ZARATE CARDENAS Héctor Manuel Moya Cessa (2013)

The interaction of a two-level atom with a single-mode quantized field is one of the simplest models in quantum optics. Under the rotating wave approximation, it is known as the Jaynes-Cummings model and without it as the Rabi model. Real-world realizations of the Jaynes-Cummings model include cavity, ion trap and circuit quantum electrodynamics. The Rabi model can be realized in circuit quantum electrodynamics. As soon as nonlinear couplings are introduced, feasible experimental realizations in quantum systems are drastically reduced. We propose a set of two photonic lattices that classically simulates the interaction of a single two-level system with a quantized field under field nonlinearities and nonlinear couplings as long as the quantum optics model conserves parity. We describe how to reconstruct the mean value of quantum optics measurements, such as photon number and atomic energy excitation, from the intensity and from the field, such as von Neumann entropy and fidelity, at the output of the photonic lattices. We discuss how typical initial states involving coherent or displaced Fock fields can be engineered from recently discussed Glauber-Fock lattices. As an example, the Buck-Sukumar model, where the coupling depends on the intensity of the field, is classically simulated for separable and entangled initial states.

Article

Propagation Coupled Resonators Photonic Crystals Quantum Optics Quantum Electrodynamics Guided Wave Applications CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ÓPTICA

A photonic crystal realization of a phase driven two-level atom

BLAS MANUEL RODRIGUEZ LARA ALEJANDRO ZARATE CARDENAS FRANCISCO SOTO EGUIBAR Héctor Manuel Moya Cessa (2013)

We propose a set of photonic crystals that realize a nonlinear quantum Rabi model equivalent to a two-level system driven by the phase of a quantized electromagnetic field. The crystals are exactly solvable in the weak-coupling regime; their dispersion relation is discrete and the system is diagonalized by normal modes similar to a dressed state basis. In the strong-coupling regime, we use perturbation theory and find that the dispersion relation is continuous. We give the normal modes of the crystal in terms of continued fractions that are valid for any given parameter set. We show that these photonic crystals allow state reconstruction in the form of coherent oscillations in the weak-coupling regime. In the strong-coupling regime, the general case allows at most partial reconstruction of single waveguide input states, and non-symmetric coherent oscillations that show partial state reconstruction of particular phase-controlled states.

Article

Photonic crystals Classical and quantum physics Classical simulation of quantum optics CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ÓPTICA

Amorphous silicon-liquid crystals device forphotonic applications

ÁNGEL FUENTES GARCIA María del Carmen Grados Luyando JULIO CESAR RAMIREZ SAN JUAN RUBEN RAMOS GARCIA (2013)

We demonstrate that an hydrogenated amorphous silicon (a:SiH)-liquid crystals hybrid device could be used for the recording of high resolution (0.8-2 µm) dynamic holograms. A maximum diffraction efficiency of 3.3% was obtained at low power (1.5 mW) He-Ne laser. The nonlinear refractive index change at 0.6 W/cm2 is n2~1x10−2 cm2 /W, although small compared to that obtained in dye-doped liquid crystal, is equal to the reported in pure liquid crystal although with much higher power density (~50 W/cm2 ). The device operates in the red to near-infrared part of the spectrum which makes it attractive due to its potential applications in telecommunications and military applications.

Article

Nonlinear optics Diffraction gratings Holography Liquid crystals CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ÓPTICA

Signatures of long-lived spiral patterns.

ERIC EMMANUEL MARTINEZ GARCIA (2013)

Azimuthal age/color gradients across spiral arms are a signature of long-lived spirals. From a sample of 19 normal (or weakly barred) spirals where we have previously found azimuthal age/color gradient candidates, 13 objects were further selected if a two-armed grand-design pattern survived in a surface density stellar mass map. Mass maps were obtained from optical and near-infrared imaging, by comparing with a Monte Carlo library of stellar population synthesis models that allowed us to obtain the mass-to-light ratio in the J-band, (M=L)J , as a function of (g - i) versus (i - J) color. The selected spirals were analyzed with Fourier methods in search for other signatures of long-lived modes related to the gradients, such as the gradient divergence toward corotation, and the behavior of the phase angle of the two-armed spiral in different wavebands, as expected from theory. The results show additional signatures of long-lived spirals in at least 50% of the objects.

Article

Galaxies: kinematics and dynamics Galaxies: photometry Galaxies: spiral Galaxies: stellar content Galaxies: structure CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA

Construction of Social Sustainability in Milk Production Systems in Central Mexico

MONICA ELIZAMA RUIZ TORRES Ana Lorga da Silva CARLOS MANUEL ARRIAGA JORDAN FRANCISCO ERNESTO MARTINEZ CASTAÑEDA (2021)

Objective: To build mathematical models to evaluate the social sustainability of small-scale milk production systems. Design/Methodology/Approach: Thirty small-scale cowsheds were analyzed. Two models were built using multivariate regression, estimated with ordinary least squares and considering the factors that producers perceive as important for social sustainability. Results: The first model (ER) included tangible variables and the second intangible variables (SR). Both models explained more than 80% of the variables associated with social sustainability. Study Limitations/Implications: The results represent an effort to link the statistical analysis with qualitative data that is difficult to quantify. Conclusions: The ER and SR models represent a proposal for counting immaterial indicators so they can be incorporated into the sustainability analysis. Both models could be a methodological proposal to connect statistical data with purely qualitative data such as perception

This study is part of the project with key 129449/2009 financed by CONACyT

Article

Livestock production mathematical models ethnography social structures CIENCIAS SOCIALES

Mass-metallicity relation explored with CALIFA: I. Is there a dependence on the star-formation rate?⋆

Fernando Fabián Rosales Ortega (2013)

We studied the global and local M-Z relation based on the first data available from the CALIFA survey (150 galaxies). This survey provides integral field spectroscopy of the complete optical extent of each galaxy (up to 2−3 effective radii), with a resolution high enough to separate individual HII regions and/or aggregations. About 3000 individual HII regions have been detected. The spectra cover the wavelength range between [OII]3727 and [SII]6731, with a sufficient signal-to-noise ratio to derive the oxygen abundance and star-formation rate associated with each region. In addition, we computed the integrated and spatially resolved stellar masses (and surface densities) based on SDSS photometric data. We explore the relations between the stellar mass, oxygen abundance and star-formation rate using this dataset. We derive a tight relation between the integrated stellar mass and the gas-phase abundance, with a dispersion lower than the one already reported in the literature (σ∆log(o/H) = 0.07 dex). Indeed, this dispersion is only slightly higher than the typical error derived for our oxygen abundances. However, we found no secondary relation with the star-formation rate other than the one induced by the primary relation of this quantity with the stellar mass. The analysis for our sample of ~3000 individual HII regions confirms (i) a local mass-metallicity relation and (ii) the lack of a secondary relation with the star-formation rate. The same analysis was performed with similar results for the specific star-formation rate. Our results agree with the scenario in which gas recycling in galaxies, both locally and globally, is much faster than other typical timescales, such like that of gas accretion by inflow and/or metal loss due to outflows. In essence, late-type/disk-dominated galaxies seem to be in a quasi-steady situation, with a behavior similar to the one expected from an instantaneous recycling/closed-box model.

Article

Galaxy: abundances Galaxies: ISM Galaxies: fundamental parameters Galaxies: spiral Galaxies: structure Galaxies: evolution CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA

Sensado de materiales con estructuras de microondas

ROSARIO PEÑALOZA DELGADO (2018)

En este trabajo se describe el diseño de un sensor para medir permitividad dieléctrica compleja de materiales con microondas. Este circuito es basado en tecnologías novedosas de la literatura; guías de onda integradas en sustrato (Substrate Integrated Waveguide “SIW”), método de perturbación de cavidad (Cavity perturbation technique “CPT”) y epsilon cercano a cero (Epsilon near zero, “ENZ”). Este nuevo sensor utiliza una guía de onda integrada en sustrato para la caracterización de las propiedades dieléctricas. La estructura es miniaturizada usando la técnica de Epsilon Near Zero. Esta técnica ya ha sido reportada. Sin embargo, se demuestra que se puede obtener una estructura con alto Q aumentando el espesor del túnel y modificando el acoplamiento externo. Además, esta estructura está diseñada para ser reconfigurable a dos frecuencias de 2.4 GHz y 3.5 GHz mediante el uso de interruptores de metal líquido, donde los resultados experimentales son muy similares a los valores reportados en la literatura para las muestras medidas.

In this work describes the design of a measure the complex dielectric permittivity of materials with microwaves. This circuit is sensor to based on novel technologies of literature; integrated substrate waveguide "SIW", cavity disturbance technique "CPT" and Epsilon near zero "ENZ". This novel sensor using substrate integrated waveguide is presented for dielectric properties characterization. The structure is miniaturized using Epsilon Near Zero technique. This technique has already been reported. However, it is demonstrated that a high Q structure can be obtained by increasing the tunnel thickness and modifying the external coupling. In addition, this structure is designed to be reconfigurable to two frequencies 2.4 GHz and 3.5 GHz by using liquid metal switches. Cavity perturbation technique is used to measure the dielectric permittivity of some liquids, where the experimental results are very close to the values reported in the literature for the measured samples.

Master thesis

CIS- Maestría en Ingeniería Eléctrica (Instrumentación y Sistemas Digitales) INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS INGENIERÍA Y TECNOLOGÍA ELÉCTRICAS Permitividad dieléctrica compleja - Medición SIW (Guías de Onda Integradas en Sustrato) CPT (Método de Perturbación de Cavidad) Sensores para medir permitividad dieléctrica compleja – Diseño Estructuras de microondas Complex dielectric permittivity - Measurement SIW (Substrate Integrated Waveguide) CPT (Cavity Perturbation Technique) Sensor to Measure the complex dielectric permittivity – Design Microwave structures

OH Maser Sources in W49N: Probing Magnetic Field and Differential Anisotropic Scattering with Zeeman pairs using the VLBA

Eduardo Mendoza Torres (2013)

Our analysis of a VLBA 12-hour synthesis observation of the OH masers in awell-known star-forming region W49N has yielded valuable data that enables usto probe distributions of magnetic fields in both the maser columns and the inter-vening interstellar medium (ISM). The data consisting of detailed high angular-resolution images (with beam-width ∼20 milli-arc-seconds) of several dozen OH maser sources or spots, at 1612, 1665 and 1667 MHz, reveal anisotropic scatter broadening, with typical sizes of a few tens of milli-arc-seconds and axial ratios between 1.5 to 3. Such anisotropies have been reported earlier by Desai, Gwinn & Diamond (1994) and interpreted as induced by the local magnetic field parallel tothe Galactic plane. However, we find a) the apparent angular sizes on the averagea factor of about 2.5 less than those reported by Desai et al. (1994), indicating significantly less scattering than inferred earlier, and b) a significant deviation inthe average orientation of the scatter-broadened images (by ∼10 degrees) from that implied by the magnetic field in the Galactic plane. More intriguingly, for afew Zeeman pairs in our set, significant differences (up to 6σ) are apparent in thescatter broadened images for the two hands of circular polarization, even when apparent velocity separation is less than 0.1 km s⁻¹. This may possibly be the first example of a Faraday rotation contribution to the diffractive effects in the ISM. Using the Zeeman pairs, we also study the distribution of magnetic field inthe W49N complex, finding no significant trend in the spatial structure function.In this paper, we present the details of our observations and analysis leading tothese findings, discuss implications of our results for the intervening anisotropic magneto-ionic medium, and suggest the possible implications for the structure of magnetic fields within this star-forming region.

Article

Masers ISM: molecules Magnetic fields Individual (W49N) Radio lines: ISM Structure function CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA