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Facile synthesis of a TiO2-Al2O3-GnPs compound and its application in the photocatalytic degradation of Diuron

Alina De J. Zurita Yduarte Diana J. Gallegos Hernández URIEL ALEJANDRO SIERRA GOMEZ GLADIS JUDITH LABRADA DELGADO SALVADOR FERNANDEZ TAVIZON Pedro Jesús Herrera Franco SRINIVAS GODAVARTHI JOSE GILBERTO TORRES TORRES ADRIAN CERVANTES URIBE CLAUDIA GUADALUPE ESPINOSA GONZALEZ (2022, [Artículo])

"New ternary materials TiO2-Al2O3-GnPs (TAG) were prepared by using an innocuous sol-gel method with a slight modification for the addition of graphene nanoplatelets (GnPs), under room temperature and atmospheric pressure. The materials TiO2-Al2O3-GnPs were prepared with variations of concentration between 0.05 and 1 wt % of GnPs. In this study, we analyzed the physicochemical properties by X-ray diffraction (XRD) and UV-Vis spectroscopy, textural properties by N2 physisorption, morphology by scanning and transmission electron microscopy (SEM, TEM) and a chemical species analysis was carried out by X-ray photoelectron spectroscopic (XPS). The photocatalytic activity of each material was evaluated in the degradation of a model molecule, Diuron, a carcinogenic and cytotoxic herbicide used in farm fields. To determine reaction selectivity and mineralization degree, the photocatalytic reaction was monitored by using UV-Vis spectroscopy and total organic carbon (TOC). In samples with higher GnPs’ concentration, a good enough specific surface area of up to 379 m2/g was observed, and reduced band gap energy (2.8 eV) with respect to TiO2 and mixed oxide (3.2 and 3.1 eV respectively), was obtained. These resulting properties were the key indicator so that the materials could be applied as photocatalysts. In the photocatalytic activity determination, TAG-0.75 was the sample that showed the best results with respect to the mixed oxide; the highest photocatalytic conversion, the reduced average life time, and increased mineralization and reaction selectivity."

Graphene nanoplatelets Mixed oxides Sol-gel Photocatalytic degradation BIOLOGÍA Y QUÍMICA QUÍMICA QUÍMICA

Regional analysis of the wage discrimination in the indigenous workers in Mexico

Christian De la Luz-Tovar SIBYL ITALIA PINEDA SALAZAR (2023, [Artículo, Artículo])

The objective of this research is to estimate and decompose the wage gap between indigenous and non-indigenous workers by region in Mexico, to examine whether there are regional differences in the existing wage inequality that a priori affects the indigenous population and whether these differences can be attributed to the job profile of this group or by systematic labor discrimination against them. Using the data from the 2018 National Household Expenditure Revenue Survey (ENIGH-N) and the Oaxaca-Blinder decomposition, it was found that indigenous workers face a wage gap in all regions of the county. But, this gap is more pronounced in the center and south regions, where, on average, the associated component with labor discrimination has a percentage greater than 56. In contrast, in the north-central and northern regions of Mexico, the residual component is on average less than 33%, which suggests that the wage gap is explained by differences in productivity between groups.                         

Labor economics Ethnicity wage gap Indigenous population Regions Oaxaca-Blinder decomposition Economía laboral Brecha salarial étnica Población indígena Regiones Descomposición de Oaxaca-Blinder CIENCIAS SOCIALES CIENCIAS SOCIALES

Using an incomplete block design to allocate lines to environments improves sparse genome-based prediction in plant breeding

Osval Antonio Montesinos-Lopez ABELARDO MONTESINOS LOPEZ RICARDO ACOSTA DIAZ Rajeev Varshney Jose Crossa ALISON BENTLEY (2022, [Artículo])

Genomic selection (GS) is a predictive methodology that trains statistical machine-learning models with a reference population that is used to perform genome-enabled predictions of new lines. In plant breeding, it has the potential to increase the speed and reduce the cost of selection. However, to optimize resources, sparse testing methods have been proposed. A common approach is to guarantee a proportion of nonoverlapping and overlapping lines allocated randomly in locations, that is, lines appearing in some locations but not in all. In this study we propose using incomplete block designs (IBD), principally, for the allocation of lines to locations in such a way that not all lines are observed in all locations. We compare this allocation with a random allocation of lines to locations guaranteeing that the lines are allocated to

the same number of locations as under the IBD design. We implemented this benchmarking on several crop data sets under the Bayesian genomic best linear unbiased predictor (GBLUP) model, finding that allocation under the principle of IBD outperformed random allocation by between 1.4% and 26.5% across locations, traits, and data sets in terms of mean square error. Although a wide range of performance improvements were observed, our results provide evidence that using IBD for the allocation of lines to locations can help improve predictive performance compared with random allocation. This has the potential to be applied to large-scale plant breeding programs.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA Bayes Theorem Genome Inflammatory Bowel Diseases Models, Genetic Plant Breeding

Regional analysis of the wage discrimination in the indigenous workers in Mexico

Christian De la Luz-Tovar SIBYL ITALIA PINEDA SALAZAR (2023, [Artículo, Artículo])

The objective of this research is to estimate and decompose the wage gap between indigenous and non-indigenous workers by region in Mexico, to examine whether there are regional differences in the existing wage inequality that a priori affects the indigenous population and whether these differences can be attributed to the job profile of this group or by systematic labor discrimination against them. Using the data from the 2018 National Household Expenditure Revenue Survey (ENIGH-N) and the Oaxaca-Blinder decomposition, it was found that indigenous workers face a wage gap in all regions of the county. But, this gap is more pronounced in the center and south regions, where, on average, the associated component with labor discrimination has a percentage greater than 56. In contrast, in the north-central and northern regions of Mexico, the residual component is on average less than 33%, which suggests that the wage gap is explained by differences in productivity between groups.                         

Labor economics Ethnicity wage gap Indigenous population Regions Oaxaca-Blinder decomposition Economía laboral Brecha salarial étnica Población indígena Regiones Descomposición de Oaxaca-Blinder CIENCIAS SOCIALES CIENCIAS SOCIALES

Obtención de materiales nanocompuestos semiconductorsemiconductor para producción de hidrógeno por fotocatálisis heterogénea

Obtaining semiconductor-semiconductor nanocomposite materials for hydrogen production by heterogeneous photocatalysis

Yilmair Rodríguez Santillán (2023, [Tesis de maestría])

La producción de hidrógeno mediante fotocatálisis heterogénea a través del fotorreformado de metanol ha surgido como una estrategia para abordar los desafíos energéticos y ambientales actuales. Este proceso combina la conversión de una mezcla metanol/agua, con la eficiencia de la fotocatálisis para generar hidrógeno limpio y renovable. Uno de los factores más importantes en el proceso de la fotocatálisis heterogénea, es la capacidad que presenta un semiconductor para absorber luz con energía dentro del rango del espectro visible. El g-C3N4 es uno de los materiales más estudiados recientemente para la producción de hidrógeno, ya que presenta una banda prohibida de 2.7 eV, aparte de una alta estabilidad química y térmica, así como un bajo costo de producción. Sin embargo, el g-C3N4 tiene limitaciones en su eficiencia debido a la rápida recombinación del par electrón/hueco (e- /h+), lo que reduce la tasa de producción de H2. Para superar esta limitación se suelen hacer modificaciones por medio de dopantes o formando uniones con otros semiconductores, como las que se hicieron en este trabajo. El nanocompuesto que se utilizó para la producción de H2 mediante el fotorreformado de metanol es el Pt/MnCo2S4/B-g-C3N4 que consiste en una estructura formada por nitruro de carbono grafítico dopado con boro (B-g-C3N4), sulfuro de manganeso-cobalto (MnCo2S4) y platino (Pt). El B-g-C3N4 actúa como el fotocatalizador clave en la reacción de producción de H2 ya que cuenta con una estructura de banda electrónica adecuada que le permite absorber luz solar y generar pares (e-/h+) para activar la reacción. El MnCo2S4 se empleó para favorecer la separación y migración de los portadores de carga. El papel del Pt fue el de acelerar la reacción de reducción para la formación de la molécula de H2. La serie de fotocatalizadores de Pt/MnCo2S4/B-g-C3N4 que fueron sintetizados, demostraron una alta estabilidad y actividad fotocatalítica en la producción de hidrógeno a partir del fotorreformado de metanol/agua, tanto en condiciones con luz UV como en condiciones con luz visible, permitiendo alcanzar una producción de 947.9 μmol g-1 h-1 y 716.4 μmol g-1 h- respectivamente.

Hydrogen production through heterogeneous photocatalysis via methanol photoreforming has emerged as a strategy to address current energy and environmental challenges. This process combines the conversion of a methanol/water mixture with the efficiency of photocatalyst to generate clean and renewable hydrogen. One of the most crucial factors in the heterogeneous photocatalysis process is the semiconductor's ability to absorb light within the visible spectrum energy range. Recently, g-C3N4 has been extensively studied for hydrogen production due to its 2.7 eV bandgap, high chemical and thermal stability, and low production cost. However, g-C3N4 has limitations in its efficiency due to the rapid recombination of electron/hole pairs (e-/h+), which reduces the H2 production rate. To overcome this limitation, modifications are often made through dopants or forming junctions with other semiconductors, as is done in this study. The nanocomposite used for hydrogen production via methanol photoreforming is Pt/MnCo2S4/B-g-C3N4, which consists of a structure composed of borondoped graphitic carbon nitride (B-g-C3N4), manganese-cobalt sulfide (MnCo2S4) and platinum (Pt). B-gC3N4 acts as the critical photocatalyst in the H2 production reaction. It possesses an appropriate electronic band structure that absorbs solar light and generates electron-hole pairs (e-/h+) to activate the reaction. MnCo2S4 was used to promote the separation and migration of charge carriers. The role of Pt is to accelerate the reduction reaction to form H2 molecules. The series of synthesized Pt/MnCo2S4/B-g-C3N4 photocatalysts demonstrated high stability and photocatalytic activity in hydrogen production via methanol/water photoreforming, both under UV and visible light conditions, achieving a production rate of 947.9 μmol g-1 h-1 and 716.4 μmol g-1 h-1, respectively.

hidrógeno, fotocatálisis, fotorreformado, metanol, nanocompuesto hydrogen, photocatalyst, photoreforming, methanol, nanocomposite INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

Impact of automation on enhancing energy quality in grid-connected photovoltaic systems

Virgilio Alfonso Murillo Rodríguez NOE VILLA VILLASEÑOR José Manuel Robles Solís OA Guirette-Barbosa (2023, [Artículo])

Rapid growth in the integration of new consumers into the electricity sector, particularly in the industrial sector, has necessitated better control of the electricity supply and of the users’ op-erating conditions to guarantee an adequate quality of service as well as the unregulated dis-turbances that have been generated in the electrical network that can cause significant failures, breakdowns and interruptions, causing considerable expenses and economic losses. This research examines the characteristics of electrical variations in equipment within a company in the industrial sector, analyzes the impact generated within the electrical system according to the need for operation in manufacturing systems, and proposes a new solution through automation of the regulation elements to maintain an optimal system quality and prevent damage and equipment failures while offering a cost-effective model. The proposed solution is evaluated through a reliable simulation in ETAP (Energy Systems Modeling, Analysis and Optimization) software, which emulates the interaction of control elements and simulates the design of electric flow equipment operation. The results demonstrate an improvement in system performance in the presence of disturbances when two automation schemes are applied as well as the exclusive operation of the capacitor bank, which improves the total system current fluctuations and improves the power factor from 85.83% to 93.42%. Such a scheme also improves the waveform in the main power system; another improvement result is when simultaneously operating the voltage and current filter together with the PV system, further improving the current fluctuations, improving the power factor from 85.83% to 94.81%, achieving better stability and improving the quality of the waveform in the main power grid.

This article belongs to Special Issue Advances and Optimization of Electric Energy System.

Power quality Capacitor bank Voltage and current filter Photovoltaic system INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS OTRAS ESPECIALIDADES TECNOLÓGICAS OTRAS OTRAS