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Non-Darcy Flow in Molding Sands

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Open Journal of Applied Sciences 2024年第4期14卷 976-982页

作者： Miguel A. Barron-Meza joan reyes-miranda Daniel Flores-Sanchez Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

Darcy’s law is widely used to describe the flow in porous media in which there is a linear relationship between fluid velocity and pressure gradient. However, it has been found that for high numbers of Reynolds this law ceases to be valid. In this work, the Ergun equation is employed to consider the non-linearity of air velocity with the pressure gradient in casting sands. The contribution of non-linearity to the total flow in terms of a variable defined as a non-Darcy flow fraction is numerically quantified. In addition, the influence of the shape factor of the sand grains on the non-linear flow fraction is analyzed. It is found that for values of the Reynolds number less or equal than 1, the contribution of non-linearity for spherical particles is around 1.15%.

关键词： Darcy’s Law Molding Sands Non-Darcy Flow Reynolds Number Shape Factor

Mathematical Modelling of Einstein’s Rate Equations for Zinc Phosphate Glass with Er3+-Yb3+

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Open Journal of Applied Sciences 2021年第9期11卷 1038-1045页

作者： Frida Lissete Flores Rivera Grethell Georgina Pérez-Sánchez Miguel Angel Barron-Meza joan reyes miranda Dulce Yolotzin Medina Velázquez Division of Basic Science and Engineering Universidad Autónoma Metropolitana México City México

There is a constant growth in the demand of data information transmission capacity, that is, more and more people send data, voice, video signals, among others, through communications networks. Due to the above there is great interest in improving network devices, such as optical amplifiers, which must cover a large bandwidth and generate greater gain than those currently available. For this reason in this work a computational simulation for a Quasi-system was carried out three energy levels of Erbium and Ytterbium varying their concentrations and proving that they are optimal candidates in a zinc phosphate matrix as this type of glass contains properties such as, high transparency, low melting point, high thermal stability, high gain density due to high solubility, low refractive index and low dispersion, which makes them optimal as signal amplifiers. The results confirm that by increasing the doping of the Erbium ion the gain of the amplifier decreases, contrary to the Ytterbium ion that by increasing the doping the gain of the amplifier increases.

关键词： Optical Telecommunications Rare Earths Doping Optical Amplifier Gain

Copper Oxide Inked with Dye Obtained from the Lactarius Indigo Fungus for Energy Production

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Journal of Materials Science and Chemical Engineering 2022年第11期10卷 36-51页

作者： Abigail Bautista Castañeda Maria Guadalupe Montes De Oca Dulce Yolotzin Medina Velazquez Jorge Iván Aldana González Pedro Adrian Martinez Montolla joan reyes miranda Miguel Angel Barron Universidad Autónoma Metropolitana Departamento de Materiales Ciencias Básicas e Ingeniería Reynosa Tamaulipas México Instituto Politécnico Nacional ESIQIE UPALM S/N Col. Mexico City México

The results obtained from the characterization of a copper deposit on indium doped tin oxide (ITO), inked with natural dye extracted from the Lactarius indigo fungus, for use in Gratzel type solar cells are reported. An electrolyte composed of 0.1 M HNO3 and 0.5 M CuSO4 was used, this solution was prepared for copper deposits on the ITO. Cyclic voltammetry was performed at different scan rates to obtain the reduction zone for deposition between potentials of ?100 to ?500 mV. The dye was obtained from the indigo Lactarius fungus from maceration, once the inked deposits were obtained, characterizations were performed, the initial test was to obtain the Ultraviolet-Visible (UV-visible) of the pure dye, and later the same test was performed on the inked oxide. Electrochemical Impedance Spectroscopy (EIS) was performed on the samples, as well as Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM), to characterize the material properties for its application.

关键词： Copper Oxide Ink Dye Energy Production Indigo Milk Mushroom

Luminescent Properties of the Mn2+Ion in Zinc Phosphate Glass

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Open Journal of Applied Sciences 2021年第11期11卷 1212-1217页

作者： Frida Lissete Flores Rivera Dulce Yolotzin Medina Velazquez Gabriela Verenice Arredondo Martínez Jorge Roberto Oliva Uc Carlos Eduardo Rodriguez Garcia Miguel Angel Barron-Meza joan reyes miranda Autonomus Metropolitan University Material Area Mexico City Mexico Potosino Institute for Scientific and Technological Research Advanced Materials Division San Luis Mexico Faculty of Physics-Mathematics Autonomous University of Coahuila Saltillo Mexico

In the development of new optoelectronic devices, mainly those related to solid state technology (SSL), the generation of luminescent materials with high intensity in visible region and low cost is of vital importance. For this reason, this work presents the luminescent properties of zinc phosphate glasses doped with the manganese ion 2+. The manganese ion offers a series of advantages with respect to rare earths, such as a more accessible cost and an intense emission in the red color that make it a great candidate for the generation of new optoelectronic devices. The methodology for the synthesis is presented in this work, as well as its luminescent properties, for concentrations of 2%, 10%, 13% and 15% atomic.

关键词： Luminescence Manganese Advanced Glasses

Blue-Red Tuning Emission of ZnO: Europium Quantum Dots with Different Excitation Wavelengths

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Open Journal of Applied Sciences 2018年第10期8卷 441-445页

作者： Primitivo Ortiz Maldonado Ana K. Chavez-Alvarado Francisco J. Rodríguez Gutierrez joan reyes miranda Dulce Y. Medina Velazquez Miguel A. Barron Elizabeth Garfias García Universidad Autónoma Intercultural de Sinaloa El Fuerte México División de Ciencias Básicas e Ingeniería Universidad Autónoma Metropolitana Reynosa Tamaulipas México

Optoelectronic applications require the development of new fluorescent and efficient luminescent materials, free of toxicity, low in cost, and easy to produce. In this way the synthesis of zinc-oxide (ZnO) quantum dots (QDs) has recently received special attention due to their good optical, electrical and chemical properties with low production costs and blue light emission. In this work ZnO QDs were successfully doped with europium in order to obtain a tunable emission luminescence from blue emission of ZnO to red emission of europium as a function of wavelength excitation. Results show an efficient blue to red tuning when the excitation wavelength was changed from 317 nm to 395 nm, respectively. This opens the possibility of having new optical devices to produce different color emission using the same material.

关键词： Chromaticity Diagram Emission Spectra Europium Luminescence Red-Blue Tuning ZnO Quantum Dots White Light

Unsteady Non-Uniform Flow of Molten Metals in Rectangular Open Channels

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World Journal of Engineering and Technology 2022年第3期10卷 593-604页

作者： Miguel A. Barron joan reyes Dulce Y. miranda Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Mexico City Mexico

In the metallurgical industries, it is very important to characterize the flow of molten metals in open channels given that they are transported through these devices to different plant sections. However, unlike the flow of water which has been studied since ancient times, the flow of molten metals in open channels has received little attention. The unsteady non-uniform flow of blast furnace molten pig iron in a rectangular open channel is analyzed in this work by numerical solution of the Saint-Venant equations. The influence of mesh size on the convergence of molten metal height is studied to determine the proper mesh and time step sizes. A sinusoidal inflow pulse is imposed at the entrance of the channel in order to analyze the propagation of the resulting wave. The influence of the angle of inclination of the channel and the roughness coefficient of the walls on the amplitude and the dynamic behavior of the height of the molten metal are analyzed. Phase portraits of the channel state variables are constructed and interpreted. Numerical simulations show that as the angle of inclination of the channel increases, the amplitude of the formed wave decreases. From 10 degrees onwards, the peak of the wave descends even below the initial height. On the other hand, the roughness coefficient affects the molten pig iron height profiles in an inverse way than the angle of inclination. The amplitude of the formed wave increases as the roughness coefficient increases.

关键词： Molten Metals Flow Non-Uniform Flow Open Channels Pig Iron Transport Saint-Venant Equations Sinusoidal Pulse Unsteady Flow

The Periaqueductal Gray and Its Extended Participation in Drug Addiction Phenomena

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Neuroscience Bulletin 2021年第10期37卷 1493-1509页

作者： Priscila Vazquez-Leon Abraham miranda-Paez Jesus Chavez-reyes Gonzalo Allende Paulino Barragan-Iglesias Bruno A.Marichal-Cancino Departamento de Fisiologia y Farmacologia Centro de Ciencias BasicasUniversidad Autonoma de AguascalientesCiudad Universitaria20131 AguascalientesAgs.Mexico Departamento de Fisiologia Escuela Nacional de Ciencias BiologicasInstituto Politecnico NacionalWilfrido Massieu esq.Manuel Stampa s/n Col.Nueva Industrial Vallejo07738 Gustavo A.MaderoMexico CityMexico

The periaqueductal gray(PAG)is a complex mesencephalic structure involved in the integration and execution of active and passive self-protective behaviors against imminent threats,such as immobility or flight from a *** activity is also associated with the integration of responses against physical discomfort(e.g.,anxiety,fear,pain,and disgust)which occurs prior an imminent attack,but also during withdrawal from drugs such as morphine and *** PAG sends and receives projections to and from other well-documented nuclei linked to the phenomenon of drug addiction including:(i)the ventral tegmental area;(ii)extended amygdala;(iii)medial prefrontal cortex;(iv)pontine nucleus;(v)bed nucleus of the stria terminalis;and(vi)*** models have suggested that the PAG contributes to the modulation of anxiety,fear,and nociception(all of which may produce physical discomfort)linked with chronic exposure to drugs of *** produced by the major pharmacological classes of drugs of abuse is mediated through actions that include participation of the *** support of this,there is evidence of functional,pharmacological,***/or genetic alterations in the PAG during the impulsive/compulsive intake or withdrawal from a *** to its small size,it is difficult to assess the anatomical participation of the PAG when using classical neuroimaging techniques,so its phys-iopathology in drug addiction has been underestimated and poorly *** this theoretical review,we discuss the involvement of the PAG in drug addiction mainly via its role as an integrator of responses to the physical discomfort associated with drug withdrawal.

关键词： Periaqueductal gray Reward circuit Antireward circuit Alcohol Caffeine Cannabis Opioids Stimulants

Effect of the Density of Molten Metal on the Raining Phenomenon in Horizontal Centrifugal Casting

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Open Journal of Applied Sciences 2024年第7期14卷 1918-1926页

作者： Miguel A. Barron joan reyes Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

In this work the influence of the density of the molten metal on the emergence of the raining phenomenon in the horizontal centrifugal casting process is numerically studied. Transient 2D numerical simulations were carried out using Computational Fluid Dynamics software. Three molten metals with different density, namely aluminum, iron and lead, and three angular frequencies, namely 50, 66 and 77 rad/s were considered. It is found that the density of the molten metal significantly affects the emergence, transient or permanent, of the rain phenomenon. However, the magnitude and duration of the rain phenomenon depend on the angular frequency of the rotating mold. Likewise, since gravitational forces affect the metal according to its density, the value of the critical rotation speed of the mold is also affected.

关键词： Angular Frequency Centrifugal Force Computational Fluid Dynamics Critical Rotation Speed G Factor Horizontal Centrifugal Casting Molten Metal Density

Analysis of the Flow of a Molten Slag in an Open Channel Using Transient and Steady-State Solutions of the Saint-Venant Equations

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World Journal of Engineering and Technology 2024年第4期12卷 976-986页

作者： Miguel A. Barron joan reyes Aristeo Garrido Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

In recent years, metallurgical slags have been increasingly used as materials for the manufacture of cement, pavement and filling material. The transport of the molten slag to the receiving pots is carried out through open channels. The transient and steady-state flow of a molten slag in a rectangular open channel is numerically analyzed here. For the transient flow, the Saint-Venant equations were numerically solved. For the steady-state flow, the derivatives in time and space in the Saint-Venant equations were set equal to zero and a polynomial of degree 3 is obtained whose roots are the slag height values. It was assumed that the viscosity of the slag has an Arrhenius-type behavior with temperature. Four values of temperature values, namely 1723.15, 1773.15, 1823.15, 18873.15 ˚K, and five values of the angle of inclination of the channel, namely 1, 2, 3, 4, 5 degrees, are considered. Numerical results show that the steady-state values of the height and velocity of the molten slag depend strongly on the temperature of the slag and the angle of inclination of the channel. As the slag temperature and channel angle increase, the value of the steady-state slag height decreases. The value of the steady-state slag velocity increases as the slag temperature and channel inclination angle increase.

关键词： Molten Slag Open Channel Phase-Portrait Saint-Venant Equations Steady State Transient Solution