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Numerical Simulation of a Batch-Type Reheating Furnace

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World Journal of Engineering and Technology 2018年第4期6卷 713-722页

作者： Francisco J. Nava Miguel A. Barron dulce Y. medina Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

A numerical analysis of a batch-type reheating furnace with and without thermal load was carried out using the Computational Fluid Dynamics technique. The furnace has two premixed burners and methane is used as fuel. Previous to the numerical experiments, a mesh convergence test was carried out and the average internal furnace temperature and the exhaust gases temperature were monitored as function of the number of cells in the discretized system. The influence of the Air/Fuel ratio, the position of the burners, and the thermal load on the average internal temperature, the exhaust gases temperature, and the molar fraction of methane and oxygen in the exhaust gases was numerically explored.

关键词： Air/Fuel Ratio CFD Simulation Exhaust Gas Numerical Simulation Premixed Burner Reheating Furnace Thermal Load

Lance Design for Argon Bubbling in Molten Steel

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World Journal of Engineering and Technology 2020年第3期8卷 317-328页

作者： Servando De la Cruz Miguel A. Barron dulce Y. medina Joan Reyes Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Mexico City Mexico

Three lance designs for argon bubbling in molten steel are presented. Bottom bubbling is considered too. Geometries considered are straight-shaped, T-shaped, and disk-shaped. The bubbling behavior of these lances is analyzed using Computational Fluid Dynamics, so transient three dimensional, isothermal, two-phase, numerical simulations were carried out. Using the numerical results, the bubble distribution and the open eye area are analyzed for the considered lance geometries. The plume volume is calculated from the open eye area and the lance immersion depth using geometrical considerations. Among the three lance designs considered, disk-shaped lance has the bigger plume volume and the smaller mixing time. As the injection lance is deeper immersed, the power stirring is increased and the mixing time is decreased.

关键词： Bottom Injection Bubble Plume Computational Fluid Dynamics Lance Design Molten Steel Open Eye

Influence of Synthesis Parameters on Luminescence of Thenoyltrifluoroacetone Europium Powders

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Journal of Materials Science and Chemical Engineering 2018年第8期6卷 1-8页

作者： dulce Y. medina-velazquez Manuel Barraza Miguel Barron Isaias Hileio Victor Colin División de Ciencias Básicas e Ingeniería Universidad Autónoma Metropolitana-Azcapotzalco Reynosa Mexico

In the last years the development of new luminescent materials was grow highly in order to find efficient materials with low cost of processing. In this way the organic luminescent materials have special attention because its special characteristics, like antenna effect, low temperature processing, possibility to make translation to polymeric and flexible compounds. In this work luminescent powders of TTA:Eu3+ by sol-gel method were synthesized in order to define the synthesis parameters of the highest luminescence. The temperatures of heat treatment were 80°C, 100°C, 200°C and the concentration of Europium where 10%, 20%, 30% and 40% mol (TTA-10Eu, TTA-20Eu, TTA-30Eu, and TTA-40Eu). Fourier Transform Infrared Rays analysis (FTIR) and emission luminescence measures, the best conditions of synthesis were obtained at 40% mol of Europium and 80°C of heat treatment, at 272 nm of excitation. All the samples present the corresponded Eu3+ ion transitions the 5D0 → 7FJ (J = 0, 1, and 2). This confirms the great possibilities of these materials for optoelectronic applications.

关键词： Luminescence Europium Organic Compounds Thenoyltrifluoroacetone Antenna Effect

Synthesis of ZnS:Tm<sup>3+</sup>Nanoparticles by the Polyol Method

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Open Journal of Applied Sciences 2019年第7期9卷 613-619页

作者： Francisco Jesus Rodriguez Joan Reyes dulce Y. medina Miguel Angel Barron Catalina Haro-Perez Ciencias Básicas e Ingeniería Universidad Autónoma Metropolitana Mexico City México

In this work, the synthesis of undoped and Tm-doped ZnS nanoparticles is successfully carried out by the polyol method. From XRD analyses, it was confirmed that both types of particles possess the cubic zinc blend structure of the ZnS, and that the structure is not altered by doping. The crystallite size computed by the Scherrer equation is about 9 ± 1 nm. From photoluminescence analyses, the results show that the excitation spectrum has two excitation peaks at 304 nm and 356 nm;by exciting at 304 nm, a strong blue emission is observed at 420 nm, while exciting at 356 nm the characteristic Tm transition 1G4 → 3H6 is observed at 417 nm. By doping with Tm ions, the emission color changes from pure blue to sky according to the change in CIE coordinates from x = 0.15, y = 0.015 to x = 0.18, y = 0.17, respectively.

关键词： Luminescence Zinc Sulfide Blue Emission

Synthesis of Tenoltrifluoroacetone Composite Doped with Terbium, Dysprosium and Europium Encapsulated in Silica Oxide Matrix

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Journal of Surface Engineered Materials and Advanced Technology 2020年第4期10卷 63-74页

作者： Yazmin Francisco dulce medina Miguel Barron Joan Reyes Pedro Adrian Martinez Angel de Jesus Morales Elizabeth Garfias Universidad Autónoma Metropolitana Departamento de Materiales Ciencias Básicas e Ingeniería Reynosa Tamaulipas México Instituto Politécnico Nacional ESIQIE UPALM S/N Mexico City México

The synthesis of the thenoyltrifluoroacetone compound doped with terbium, dysprosium and europium encapsulated in a silica matrix (TTA:Tb:Dy:Eu@SiO2) were performed by the sol-gel method. The precursors to obtain the vitreous phase (SiO2) were: Tetraethylorthosilicate (TEOS, C8H2O4Si, 98%, Aldrich), and ethyl alcohol (CH3CH2OH, 99.5%, Meyer), distilled water and 0.05 ml of hydrochloric acid (HCl, Meyer). The sample with molar ratio 20:80 TTA:Tb:Dy:Eu@SiO2 has the best emission intensity. Thermogravimetric analysis (TGA) shown that silica encapsulated samples decompose at lower temperatures than pure TTA:Tb:Dy:Eu luminescent material. Fourier Transform Infrared (IR-TF) shown the characteristic Si-O-Si bands that are presented at a wavelength of 1049, 853 and 440 cmǃ confirming that the luminescent material is encapsulated in a silica matrix, finally X-ray diffraction (XRD) shown that TTA:Tb:Dy:Eu@SiO2 composite is amorphous.

关键词： Synthesis Luminescence Composite Sol-Gel Terbium Dysprosium and Europium

Red, White and Blue Light Emission from Europium Doped Al2O3 Confined into a Silica Matrix

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Open Journal of Applied Sciences 2018年第8期8卷 338-345页

作者： Joan Reyes dulce Y. medina Miriam Aguilar Miguel A. Barron Elizabeth Garfias Angel de Jesus Morales Ciencias Básicas e Ingeniería Universidad Autónoma Metropolitana-Azcapotzalco Reynosa México Instituto Politécnico Nacional ESIQIE Mexico City México

The main drawbacks of fluorescent activated lanthanide luminescent materials in practical optoelectronic applications are the high cost of raw material and the limitation of a specific color depending on the lanthanide ion. In this work, the synthesis of red, white and blue light emitting composite powders of Al2O3:Eu3+@SiO2 were successfully synthesized by the hydrolysis and condensation reactions of TEOS as the raw precursor of silica matrix on the Al2O3:Eu3+ surface. With the aim to change the CIE coordinates different weight ratios of Al2O3:Eu3+/SiO2 powders from 13Al/87Si to 5Al/95Si were prepared. Besides, various excitation wavelength from 280 to 340 nm was used in order to change the ratio intensity;Ired/Iblue, between the red emission coming from the 5D0→7F2 transition of Eu3+ ions and the blue band of silica matrix. Chemical evolution of the hydrolysis and condensation reaction of TEOS were conducted by FTIR spectroscopy. The results indicate that from 500°C a complete TEOS to SiO2 transformation is carried out.

关键词： Luminescent Lanthanide Luminescence White Emission Aluminium Oxide

Lithium Recovery from Electrodes in Cellphone Batteries through the Leaching Process with Organic Agents Assisted by Ultrasound

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Journal of Materials Science and Chemical Engineering 2018年第9期6卷 1-5页

作者： Pedro A. Martínez Juan C. Orozco Alejandro Alonso Rosa M. Luna Miguel A. Barron dulce Y. medina Elizabeth Garfias-García División de Ciencias Básicas e Ingeniería Universidad Autónoma Metropolitana Reynosa Tamaulipas México

The present work proposes a mean for recovery of metals used in current ion-lithium batteries, like lithium, cobalt and nickel, using organic agents and ultrasound instead of the more aggressive and less environment friendly method with sulfuric acid. This is especially useful in those countries that doesn’t have lithium deposits and have a growing demand of such batteries, reducing the economic loss this represents. During the process, variables such as temperature, leaching agent concentration and ultrasound frequency were modified, using concentrations of 0.5 M (molar), 1 M and 1.5 M of sodium citrate, temperatures of 25°C, 55°C and 60°C and also ultrasound frequencies of 20 KHz, 30 KHz and 40 KHz. It was found that the best combination of these variables that yielded the most quantity of the desired metal was 0.5 M concentration for both lithium and nickel, while using 60°C and no ultrasound with Li and 55°C and 40 KHz for Ni. For Co the best variables discovered were 1.5 molar concentration, 60°C and 40 KHz.

关键词： Lithium Leaching Organic Agents Ion-Lithium Batteries Ultrasound Leaching Sodium Citrate

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

Synthesis of Tenoltrifluoroacetone Composite Doped with Terbium, Dysprosium and Europium Encapsulated in Silica Oxide Matrix

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