Universidad La Salle Chihuahua
Recent publications
The use and transformation of biomass into highly valuable products is a key element in circular economy models. The purpose of this research was to characterise the volatile compounds and the temperature at which they are emitted during the thermal decomposition by pyrolysis of algal biomass while looking at three different types: (A1) endemic microalgae consortium, (A2) photobioreactor microalgae consortium and (A3) Caribbean macroalgae consortium. Furthermore, the ultimate (CHON) and proximate (humidity, volatile solids and ashes) compositions of the algal biomass were determined. Some volatile species were identified as having potential industrial interest for use as precursors and intermediaries, such as commercially used aromatic compounds which if not suitably managed can be harmful to our health and the environment. It is concluded that the pyrolysis of algal biomass shows potential for the generation of valuable products. The information generated is useful, especially the temperature at which volatility occurs, in order to access the valuable compounds offered by the algal biomasses, and under the concept of biorefinery convert the issue of biomass disposal into a sustainable source of raw materials.
Introducción: la producción de biogás es una alternativa sostenible para el aprovechamiento energético de los residuos orgánicos. Esta investigación presenta el estudio y modelación de la producción de biogás, generada por la codigestión de excreta de vaca y suero de leche. Método: se realizaron experimentos de Digestión Anaerobia (DA), utilizando reactores herméticos, a temperatura ambiente monitoreados por 75 días consecutivos con base en el método de potencial bioquímico de metano (BMP). Se utilizaron los modelos logísticos: exponencial de crecimiento máximo Gompertz y Richards modificados para representar la cinética del fenómeno de producción de metano. Resultados y discusiones: se determinó la tasa máxima de producción de metano, la duración de la fase lag, y el potencial de producción de metano acumulado. Se comparó la suma de cuadrados residual y el coeficiente de correlación para identificar el modelo matemático que mejor describe el fenómeno. Se encontró que existe un potencial para la generación de biogás y el aprovechamiento de los residuos experimentados en codigestión. Conclusiones: la experimentación y modelación matemática permitió describir el fenómeno de la producción de biogás, con residuos de la industria láctea y de los sistemas pecuarios. Los resultados de la investigación presentan el potencial de incentivar la producción de energía, en el sector agropecuario regional, a partir de la tecnología DA aprovechando los residuos de la industria láctea bajo el concepto de economía circular.
Calcium sulfate (CaSO4) is one of the most common evaporites found in the earth’s crust. It can be found as four main variations: gypsum (CaSO4∙2H2O), bassanite (CaSO4∙0.5H2O), soluble anhydrite, and insoluble anhydrite (CaSO4), being the key difference the hydration state of the sulfate mineral. Naica giant crystals’ growth starts from a supersaturated solution in a delicate thermodynamic balance close to equilibrium, where gypsum can form nanocrystals able to grow up to 11–12 m long. The growth rates are reported to be as slow as (1.4 ± 0.2) × 10−5 nm/s, taking thousands of years to form crystals with a unique smoothness and diaphaneity, which may or may not include solid or liquid inclusions. Conservation efforts can be traced back to other gypsum structures found prior to Naica’s. Furthermore, in the last two decades, several authors have explored the unique requirements in which these crystals grow, the characterization of their environment and microclimatic conditions, and the prediction of deterioration scenarios. We present a state-of-the-art review on the mentioned topics. Beyond the findings on the origin, in this work we present the current state and the foreseeable future of these astounding crystals.
Strengthening of an Al 7075 Alloy with Graphene Synthetized by an Environmental Friendly Method - Eduardo Cuadros-Lugo, Caleb Carreño-Gallardo, Jose Martin Herrera-Ramirez, Claudia López-Meléndez, Daniel Lardizabal-Gutierrez
Fabrication of Al2024 Alloy by Core-shell Structured Ti/B4C Composite Particles - Eduardo Cuadros-Lugo, Caleb Carreño-Gallardo, Ernesto Ledezma-Sillas, Claudia López-Meléndez, Jose Martin Herrera-Ramirez
Influence of Calcination Parameters over the Morphology and Formation of Co3O4 Nanoparticles - H. J. Morales-Rodriguez, Alejandro Faudoa-Arzate, W.M. Chávez-Montes, M. Sánchez-Carrillo, Paula Rebeca Realyvazquez-Guevara, Carlos Arzate-Quintana
Naica's gypsum crystals are a natural wonder thanks to their magnitude and diaphaneity, but they are susceptible to deterioration due to different climatic conditions. Through self-assembled hybrid systems, physical mechanisms for mineral growth and conservation were studied. Based on experimental data from gypsum crystals (CaSO4·2H2O) absorption models we created in the context of Density Functional Theory (DFT) in combination with PBE exchange-correlation functional. Van der Waals interactions, which had high relevance in discovering the most stable geometric configuration, were included. Results involve a systematic approach to bulk, surface, and hybrid assemblies of crystals and common pollutant such as CO2, CH4 and NO2. The inclusion of van der Waals interactions made it possible to obtain molecule-substrate bonds to compare against atomic bonds involved in the growth of the crystalline substrate. Binding energy results were consistent with physisorption interactions and revealed the adverse environmental effects on gypsum and bassanite crystals.
Improvement of Mechanical Properties of an Aluminum Alloy 7075 by Adding Reduced Graphene Oxide Trough Mechanical Milling - Volume 25 Supplement - E Cuadros-Lugo, I Estrada-Guel, JM Herrera-Ramírez, C López-Meléndez, C Carreño-Gallardo
Exploring the Reinforcing Effect of AgcNP and Al2O3NP in Aluminum Alloy 2024 Matrix Composites - Volume 25 Supplement - C. Carreño-Gallardo, E. Cuadros-Lugo, I. Estrada-Guel, C. López-Meléndez, J. M. Herrera-Ramírez
In this paper, multiwalled carbon nanotubes (MWCNTs) were synthesized by spray pyrolysis to be used later as material reinforcement in the production of MWCNTs/Al7075 aluminum composites. Both, MWCNTs and MWCNTs/Al7075 composites were microstructurally and mechanically characterized. Scanning electron microscopy (SEM) analysis shows MWCNTs formed by multiple layers rolled on themselves forming a tube shape with lengths up to 1300 µm and diameters ranging from 55 to 120 nm. MWCNTs were added to the aluminum matrix in different concentrations up to 3.0 wt%. Their dispersion in the aluminum matrix was carried out by ultrasonic/methanol method followed by high-energy mechanical milling process. The effect of MWCNTs on the morphology and mechanical behavior of composites were evaluated. Results indicate that a homogeneous dispersion of CNTs was obtained as a consequence of the dispersion routes used in the production of composites, observing no damage on their morphology. The mechanical behavior of the composites shows a noticeable improvement for MWCNTs concentrations above 2.0 wt%, with ductility similar to that found in the literature for the Al7075 commercial alloy.
The control of a homogeneous distribution of the reinforcing phase in aluminum matrix composites is the main issue during the synthesis of this kind of material. In this work, 2024 aluminum matrix composites reinforced with boron carbide were produced by mechanical milling, using 1 and 2 h of milling. After milling, powdered samples were cold consolidated, sintered and T6 heat treated. The morphology and microstructure of Al2024/B4C composites were investigated by scanning electron microscopy; analysis of X-ray diffraction peaks were used for the calculation of the crystallite size and microstrains by the Williamson–Hall method. The mechanical properties were evaluated by compression and hardness tests. B4C particles were found to be well dispersed into the aluminum matrix as a result of the high-energy milling process. The crystallite size of composites milled for 2 h was lower than those milled for 1 h. The hardness, yield strength and maximum strength were significantly improved in the composites processed for 2 h, in comparison to those processed for 1 h and the monolithic 2024 alloy.
Graphene as reinforcement agent in aluminum alloy 7075 matrix composite by using mechanical milling - Volume 24 Supplement - E. Cuadros-Lugo, I. Estrada-Guel, M. Herrera-Ramírez, C. López-Meléndez, C. Carreño-Gallardo
Nano-Mechanical and Piezoelectric Properties on PZT Thin Films - Volume 24 Supplement - D. E. Olivas-Ortega, J. Ramos-Cano, R. P. Talamantes-Soto, C. Lopez-Melendez, A. Hurtado-Macias
Graphene oxide (GO) and reduced graphene oxide (RGO) has been studied recently in fields like electronics, energy storage, biomedical applications, biosensors and as a reinforcement for metallic and polymeric matrixes. Graphene oxide can be obtained by using the dry ice method (CO2 atmosphere) [1]. This method produce magnesium chloride (MgCl2) and hydrochloric acid (HCl) as waste after obtaining the graphene oxide [2], which makes it more environment friendly compared to the Brodie method, Staudenmaier method and Hummers method, which require the use of oxidants such as concentrated sulfuric acid (H2SO4), nitric acid (HNO3) and potassium permanganate (KMnO4) which latter become toxic wastes. A classification of graphene-based materials can be performed. Initially, monolayer graphene is the one-atom-thick material in which sp 2 bonded carbon atoms are hexagonally-arranged. Few-layer graphene is the material consisting of 2-5 sheets of graphene, while multi-layer graphene consists of 5-10 layers of graphene. Moreover, graphite nanoplatelets also consist of graphene sheets but their lateral dimensions/thickness are higher than those of many-layer graphene (more than 10 layers, less than 100 nm thickness) [3]. The multilayer graphene oxide was obtained by burning metallic Mg inside a CO2 atmosphere in a cavity of dry ice. The product of the chemical reaction is a powder mixture of unreacted metallic Mg, MgO and graphene oxide which latter was cleaned in a 1:1 solution of HCl and deionized water and vacuum filtered to remove the MgCl2 produced doe the reaction of the HCl with the MgO and the metallic unreacted Mg. The graphene oxide obtained was submitted to a thermic reduction process in a Thermolyne 21100 tube furnace at 850°C in a 200 cm 3 /min flow atmosphere of 95/5 Ar-H for 1h. GO and RGO powders were characterized by XRD using a Panalytical X'Pert PRO diffractometer and by TEM using a Hitachi TEM77000. Fig. 1 shows the DRX patterns of graphene oxide and reduce graphene oxide, in which can be clearly seen the decrease of the graphene oxide reflection due to the reduction process mentioned before. Also, it can be seen a low intensity reflection of MgO which can be derivate from some residues in the cleaning process with HCl. Transmission electron microscope (TEM) images of graphene oxide and reduce graphene oxide are shown in Fig. 2. Fig. 2a shows multi-layer graphene oxide with a 7 layers structure. In fig. 2b it is noted a multi-layer reduce graphene oxide structure with an average thickness of 0.43nm. The multilayer graphene oxide and reduced graphene oxide obtained by the dry ice method and thermal reduction have a potential application in composite materials as well as in other applications. Being environmentally friendly and having a low cost production process make this method a good alternative to fabricate graphene [4]. https://www.cambridge.org/core/terms. https://doi.10.1017/s1431927618009145
Effect of Multiwall Carbon Nanotubes (MWCNs) Reinforcement on the Mechanical Behavior of Synthesis 7075 Aluminum Alloy Composites by Mechanical Milling - Volume 23 Issue S1 - C. Carreño-Gallardo, E. Uriza-Vega, I. Estrada-Guel, M. Herrera-Ramírez, R. Martínez-Sánchez, C. Lopez-Meléndez, E. Martínez-Franco
Mechanical Behavior on Microstructure of B4C Particles Reinforced 2024 Aluminum Matrix Composite Obtained by Mechanical Milling - Volume 23 Issue S1 - C. Carreno-Gallardo, I. Estrada-Guel, M. Herrera-Ramirez, R. Martinez-Sanchez, C. Lopez-Melendez
Synthesis and Characterization of Carbon Nanotubes Via Spray Pyrolysis Method - Volume 23 Issue S1 - E. Uriza-Vega, M. Herrera-Ramírez, C. Lopez-Meléndez, I. Estrada-Guel, E. Martínez-Franco, R. Martínez-Sánchez, C. Carreño-Gallardo
The present work deals with the study of some aluminum (Al) composites reinforced with metallized-graphite (MG) particles prepared by mechanical milling and powder metallurgy routes. Density, morphology evolution and mechanical performance of composites were investigated as a function of MG concentration and milling time. The as-milled powders were characterized by X-ray diffraction and optical/electron microscopy; meanwhile, the mechanical testing was carried out on cylindrical specimens prepared from powders by powder metallurgy. Evidence reveals that high-energy ball milling induce a homogeneous dispersion of graphite nanoparticles in the Al matrix; this is related to an enhancement of hardness and strength response of studied composites. The composite sample with 0.5% MG addition (in weight) reached an increase of 40% on hardness and 50% on strength (compared with pure Al sample); nevertheless an adverse effect was observed with longer milling and/or higher MG concentration.
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49 members
C. López-Meléndez
  • Parque de Innovación La Salle Chihuahua
Hector Alfredo Lopez-Aguilar
  • Facultad de Ingeniería
Oscar Chávez-Acosta
  • Parque de Innovación La Salle