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Effect of the Substitution of Sand by Rubber of Waste Tires on the Mechanical Properties of Hydraulic Concrete and Exposure to Gamma Radiation

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Journal of Minerals and Materials Characterization and Engineering 2021年第3期9卷 245-256页

作者： Jesús M. Colín de la Cruz Carmen Gabriela Guzmán Fermín Castillo Mejía Benjamin Leal Acevedo osvaldo flores cedillo Isabel Gamboa de Buen Arturo Molina Ocampo Horacio Martínez Valencia Facultad de Ciencias Químicas e Ingeniería Universidad Autónoma del Estado de Morelos Cuernavaca México Laboratorio de Espectroscopia Instituto de Ciencias Físicas Universidad Nacional Autónoma de México Cuernavaca México Instituto de Ciencias Nucleares Universidad Nacional Autónoma de México México City México Centro de Investigación en Ingeniería y Ciencias Aplicadas UAEM Cuernavaca México

For a long time and until now, rubber is the most used material for the manufacture of tires for motor vehicles. Unfortunately, once the tire meets its life cycle, the remaining rubber cannot be recycled, so the tires are discarded in collection centers and often in clandestine dumps. This represents a serious environmental problem because, in one case, these waste tires become breeding grounds for insects and wildlife that is harmful to humans. In the second case, the tires are burned, releasing highly damaging gases into the atmosphere. On the other hand, concrete is worldwide the construction material par excellence. It is basically composed of cement, gravel and sand. Mixing these three components in different proportions, their mechanical strength in compression can be increased. However, due to its fragile nature, concrete, once a crack is formed, it rapidly advances by fragmenting the material and producing its rapid collapse. In the present work, in order contribute to the care of the environment as well as to modify the fracture mode of the concrete, rubber particles obtained from waste tires were used as sand substitute in hydraulic concrete. In addition, rubber modified samples concrete were lately exposed to 70 kGy of gamma radiation in order to study the effects of this radiation on the mechanical deformation of concrete. The results showed a decrease in the mechanical properties of the concrete with rubber particles with respect to the traditional concrete itself. However, such decreases were offset by the fact that samples with rubber addition do not collapses as fast as the free rubber samples. The acquired data pave the way for research with great benefits, such as the use of recycled tires in concrete for its fracture mode modification in a beneficial way, as well as a possible decrease in the cost of concrete.

关键词： Hydraulic Concrete Scrap Tire Rubber Strength Gamma Radiation Mechanical Properties

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Cutaneous Dengue Virus Inoculation Triggers Strong B Cell Reactions but Contrastingly Poor T Cell Responses

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Virologica Sinica 2020年第5期35卷 575-587页

作者： Edith Marcial-Juárez Julio García-Cordero Raúl Antonio Maqueda-Alfaro Rafael Eduardo Saucedo-López Luvia Enid Sánchez-Torres Leticia cedillo-Barrón Leopoldo flores-Romo Department of Cell Biology Center for Advanced Research(CINVESTAV-IPN)The National Polytechnic Institute07360 Mexico CityMexico Department of Molecular Biomedicine Center for Advanced Research(CINVESTAV-IPN)The National Polytechnic Institute07360 Mexico CityMexico Immunology Department The National School of Biological Sciences(ENCB-IPN)The National Polytechnic Institute11340 Mexico CityMexico

Dengue is a global health problem without current specific treatment nor safe vaccines *** severe dengue is related to pre-existing non-neutralizing dengue virus(DENV)antibodies,the role of T cells in protection or pathology is *** cutaneous DENV infection in immunocompetent mice we previously showed the generation of PNA+germinal centers(GCs),now we assessed the activation and proliferation of B and T cells in draining lymph nodes(DLNs).We found a drastic remodelling of DLN compartments from 7 to 14 days post-infection(dpi)with greatly enlarged B cell follicles,occupying almost half of the DLN area compared to*24%in na?ve *** clusters of proliferating(Ki-67+)cells inside B follicles were found 14 dpi,representing*33%of B cells in DLNs but only*2%in noninfected *** GCs,we noticed an important recruitment of tingle body macrophages removing apoptotic *** contrast,the percentage of paracortex area and total T cells decreased by 14–16 dpi,compared to *** randomly distributed Ki-67+T cells were found,similar to non-infected ***69 expression by CD4+and CD8+T cells was minor,while it was remarkable in B cells,representing 1764.7%of change from basal levels 3 *** apparent lack of T cell responses cannot be attributed to apoptosis since no significant differences were observed compared to noninfected *** study shows massive B cell activation and proliferation in DLNs upon DENV *** contrast,we found very poor,almost absent CD4+and CD8+T cell responses.

关键词： Dengue virus(DENV) B and T cells proliferation Lymphocyte activation Lymph nodes In vivo cutaneous infection Immunocompetent mice

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Failure Analysis of Austenitic Stainless Steel Implant Screws and Prospection of Chemical Composition Using Artificial Intelligence

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World Journal of Engineering and Technology 2022年第1期10卷 98-118页

作者： Alfonso Monzamodeth Román-Sedano Bernardo Campillo Fermín Castillo osvaldo flores Facultad de Química Universidad Nacional Autónoma de México Ciudad de México México Instituto de Ciencias Físicas Universidad Nacional Autónoma de México Cuernavaca Morelos México

In this work, austenitic stainless steel screws employed in a locking compression plate for veterinarian use were investigated. These types of implants are widely utilized in bone fractures healing. Two surgical screws were extracted due to the observation of slight superficial red rust colorizing on one of the screw implants, visual evidence of probable screw rusting. From the same implant, another screw was extracted simultaneously without visual evidence of rusting. In order to characterize and analyze the different behavior of both screws, the chemical composition was characterized by atomic absorption and energy dispersive X-ray spectroscopy (EDS) coupled to a scanning electron microscope (SEM). Also, the screws were studied by metallography, optical microscopy (OM), Vickers microhardness tests, and SEM analysis. On the other hand, a prospection for alloy chemical composition limits of these types of implants was performed based on the Schaeffler-Delong diagram and the ASTM F-138 standard. To analyze the effect of the chemical composition, heat treatment, microstructure, pitting resistance equivalent number (PRE) and stacking fault energy (SFE), a genetic algorithm (GA) and an artificial neural network (ANN) were used. In accordance with the elemental analysis, the surgical screws do not fulfill the ranges of the chemical composition established by the ASTM F-138 standard. Furthermore, there were found differences between the microstructures of the screws. In regard to the prospection, the results of GA and ANN support the proposed chemical composition region on the Schaeffler-Delong diagram. The corrosion failure was associated with severe plastic deformation and the presence of precipitates. The proposal can minimize the cause of failures in these types of austenitic stainless steel implants.

关键词： Implant Screw Failure Analysis Genetic Algorithm Artificial Neural Network Austenitic Stainless Steel

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A Study of the Structural, Optical and Electrical Properties of SnS Thin Films Modified by Plasma

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材料科学与工程（中英文B版） 2013年第6期3卷 352-358页

作者： Aar6n Gomez Horacio Martinez Manuela Calixto-Rodriguez David Avellaneda Pedro Guillermo Reyes osvaldo flores Laboratorio de Fisica Avanzada Facultad de Ciencias Universidad Autonoma del Estado de Mexico Estado de Mexico Mexico Laboratorio de Espectroscopia Instituto de Ciencias Fisicas Universidad Nacional Aut6noma de Mdxico Cuernavaca MorelosMdxico Intituto de Energia Renovable Universidad Nacional Aut6noma de Mdxico Cuernavaca Morelos M~xico Facultad de Ingenieria Meconica y Electrica Universidad Autonoma de Nuevo Leon Mexico

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Effect of Microwave Power on the Zn2SnO4 Synthesis and Its Use for Photodegradation of Phenol

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Journal of Chemistry and Chemical Engineering 2014年第8期8卷 794-799页

作者： Edson Luiz Foletto Marcio Antonio Mazutti Adriano Cancelier Erico Marion de Moraes flores Edson Irineu Muller Leticia Severo Fagundes Pereira osvaldo Chiavone-Filho Andre Gundel Department of Chemical Engineering Federal University of Santa Maria Santa Maria 97105-900 Brazil Department of Chemistry. Federal University of Santa Maria Santa Maria 97105-900 Brazil Department of Chemical Engineering Federal University of Rio Grande do Norte Natal 59066-800 Brazil Department of Physics Federal University of Pampa Bage 96413-170 Brazil

Spinel structure Zn2SnO4 was successfully synthesized by microwave-assisted hydrothermal process. The effects of the microwave power on the formation and physical properties of the Zn2SnO4 particles are discussed. The products were characterized by X-ray diffraction, atomic force microscopy, infrared spectroscopy, and N2 adsorption. The results indicated that the microwave power had important influence on the formation of the spinel phase. The results also revealed that the physical properties of Zn2SnO4 particles did not change with the increase of the microwave power above 600 W, with 20 min of reaction time. Furthermore, the photocatalytic activity of the Zn2SnO4 particles for the phenol degradation under sunlight was also investigated.

关键词： Zn2SnO4 zinc stannate synthesis microwave porous material photocatalysis.

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