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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 518-526页

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

The flow of liquids in open channels has been studied since ancient Rome. However, the vast majority of published reports on flow in open channels are focused on the transport of drinking water and sewage disposal. The literature on the transport of molten metals in open channels is quite scarce. In this work, the uniform flow of pig iron and molten aluminum in rectangular open channels is studied. Specific energy curves are constructed and critical heights are analytically determined. The transition from subcritical to supercritical flow is analyzed as a function of the angle of inclination of the channel and the roughness of its walls. Manning’s equation is applied to the pig iron flow using data reported in the literature for molten aluminum. The need to correct the roughness coefficient for pig iron is observed in order to obtain results consistent with those previously reported.

关键词： Critical Height Froude Number Molten Metal Flow Open Channel Rectangular Channel Uniform Flow

A Straightforward Mathematical Model of Hot Metal Desulphurization

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Open Journal of Applied Sciences 2020年第6期10卷 318-327页

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

A straightforward kinetic model for the hot metal desulphurization process is presented. The model contains some of the most important parameters and variables that govern the process. The inputs, outputs and parameters of a desulphurization program employed at industry are discussed. The model is able to cope with different injection policies of desulphurizers such as mono- injection, co-injection or multi-injection. When compared to the rotary impeller method, results of this model shows that the weight of lime consumed in the lance injection method is lesser than that consumed in the rotary impeller method for the same conditions of the hot metal charge.

关键词： Desulphurization Hot Metal Kinetic Model Lance Injection Rotary Impeller

Bubbling to Jetting Transition during Argon Injection in Molten Steel

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World Journal of Engineering and Technology 2020年第4期8卷 605-616页

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

Bubbling to Jetting Transition is of the outmost importance in metallurgical processes given that the flow regime influences the refining rates, the refractory erosion, and the blockage of injection nozzles. Bubbling to jetting transition during subsonic bottom injection of argon in molten steel is studied here. The effect of the molten steel height, the injection velocity, the nozzle diameter, and the molten steel viscosity on the jet height and the bubbling to jetting transition is numerically analyzed using Computational Fluid Dynamics. Five subsonic argon injection velocities are considered: 5, 25, 50, 100 and 150 m/s. Three values of the metal height are taken into account, namely 1.5 m, 2 m and 2.5 m. Besides, three values of the nozzle diameters are considered: 0.001 m, 0.005 m and 0.01 m. Finally, three values of the molten steel viscosity are supposed: 0.0067, 0.1 and 1 kg/(m·s). It is observed that for the argon-molten steel system, the bubbling to jetting transition occurs for an injection velocity less than 25 m/s and that for the range of viscosities considered, the molten steel viscosity does not exert significant influence on the jet height and the bubbling to jetting transition. Due to the jet instability at subsonic velocities, a second transition, namely jetting to bubbling, is appreciated.

关键词： Argon Injection Bubbling to Jetting Transition CFD Injection Velocity Jet Height Molten Steel Nozzle Diameter

Analysis of Molten Metal Distribution in the Mold of a Horizontal Centrifugal Casting

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Open Journal of Applied Sciences 2020年第7期10卷 444-454页

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

It is numerically studied the influence of the angular velocity, the molten metal viscosity, and the mold wall roughness on the molten metal distribution in the mold of a horizontal centrifugal casting process. The undesirable raining phenomenon sometimes arises in horizontal centrifugal casting. It occurs when the molten metal rains or falls from the top of the mold to the bottom while the mold is rotating. Using Computational Fluid Dynamics simulations, the conditions for the emergence of the raining phenomenon were explored in this work. For the system considered, angular velocities less than 77 rad/s cause the emergence of the raining phenomenon and accumulation of the molten metal in the lower part of the mold, whereas angular velocities greater than 77 rad/s produce a constant thickness of the molten metal and prevent raining.

关键词： Angular Velocity Centrifugal Casting Computational Fluid Dynamics Molten Metal Viscosity Wall Roughness

Interaction between a Liquid Surface and an Impinging Gas Jet

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World Journal of Engineering and Technology 2021年第4期9卷 793-803页

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

The water-air and Wood’s metal-air systems are modeled by means of Computational Fluid Dynamics to study the interaction between a liquid surface and an impinging air jet under the near field blowing conditions. The effect of the air jet velocity, the height of the injection lance, and the density of the liquid on the depth of the formed cavity is numerically studied. The CFD results of the cavity depth are compared with results previously reported by other authors. The emergence of the splashing phenomenon is predicted in terms of the critical velocity for each liquid-air system. Besides, the blowing number indicates that the drop generation rate is not significant for jet velocities below the critical velocity, and therefore neither the splashing is significant.

关键词： Cavity Depth CFD Impinging Gas Jet Lance Height Liquid-Gas Interaction Splashing

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

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

Application of a Pulsed Electric Field to Modify the Free Energy of the Active Site of an Azoreductase

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Journal of Applied Mathematics and Physics 2024年第1期12卷 249-255页

作者： Jesus Magyber de Jesus miranda Pedro Guillermo reyes-Romero Jorge Mulia-Rodríguez Daniel Osorio-González Molecular Biophysics Laboratory Faculty of Sciences Autonomous University of State of Mexico Toluca Mexico Advanced Physics Laboratory Faculty of Sciences Autonomous University of State of Mexico Toluca Mexico

The Gibbs free energy is strongly related to the stability and catalytic function of an enzyme through the energetic changes that occur in the chemical reactions the enzyme catalyzes. In this in silico study, a pulsed electric field was applied to an azoreductase, and its effect on the Gibbs free energy of molecular docking with two dyes was measured. We propose that certain stimuli from a pulsed electric field favor the structural stability of the enzyme by promoting an arrangement in the active site, potentially leading to an enhancement of enzymatic activity overall.

关键词： Pulsed Electric Field Molecular Dynamics Docking Azoreductase

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