Autor: HECTOR MANUEL HERNANDEZ GARCIA

Determinación de la constante acústico-elástica en aceros cementados 4320 y soldados por el proceso GMAW

MARIO ALBERTO SOLIS ALVAREZ HECTOR MANUEL HERNANDEZ GARCIA FRANCISCO ALFREDO GARCIA PASTOR (2014)

Las ondas acústicas generadas por un equipo de ultrasonido se propagan en dos ondas:

1) longitudinales y 2) transversales. Las primeras, muestran perturbaciones por una

tensión normal y las segundas son perturbadas por tensiones de cizallamiento. Por lo

tanto, en este trabajo de investigación mediante el análisis de las ondas ultrasónicas, se

llevó a cabo la medición de la constante acústico-elástica usando un equipo de

ultrasonido para correlacionar los esfuerzos residuales con las constantes acústicoelástico

durante el calentamiento y enfriamiento de muestras de aceros 4320 soldados por

el proceso GMAW. Los resultados de la constante acústica-elástica muestran que el acero

tiene un valor de 2.37 durante el calentamiento y 2.18 en el enfriamiento. Estos valores

muestran la correlación del efecto del esfuerzo térmico con la velocidad de propagación

de la onda de ultrasonido (viaje) en el acero, es decir, a mayor temperatura, la onda tarda

más en recorrer la muestra de acero, indicando deformación. En contraste, en el

enfriamiento la velocidad de onda es más rápida, el cual indica menor deformación. Cabe

mencionar que la determinación de la constante acústico-elástica se midió en aceros con

granos austeníticos de 8.92 ASTM, previamente medido.

Memoria de congreso

constante acústico-elástica en aceros INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES

Increase in Hardness and Chloride Corrosion Resistance of 6061 Aluminum Alloy by Pulsed Plasma Nitriding

HECTOR MANUEL HERNANDEZ GARCIA JUAN CARLOS DIAZ GUILLEN EVERARDO EFREN GRANDA GUTIERREZ (2013)

Enhancement of hardness and corrosion resistance of aluminum alloys persist as an important challenge in order to increase the lifetime of industrial parts and accessories. This improvement of surface properties must be accomplished by low cost and minimum environmental impact processes. On these considerations, in the present work DC pulsed plasma nitriding at rough vacuum (1.9 torr) was carried out on 6061 aluminum alloy using different N2/Ar mixtures (100/0, 50/50 and 75/50) to sustain the DC glow discharge. Influence of gas mixture on surface morphology, hardness, phases composition and corrosion performance was evaluated through scanning electron microscopy, Vickers micro indentation, X-ray diffraction and potentiodynamic polarization curves (3.5% NaCl), respectively. For the better evaluated case (50N2/50Ar mixture), results show the increase in surface hardness from 113 to 148 HV0.025, and the decrease in the corrosion current value to an a half respect untreated sample. The increasing in hardness and corrosion performance of evaluated aluminum alloy was attributed to the chemical surface modification by formation of a thin layer constituted by cubic and hexagonal aluminum nitrides.

Artículo

Nitruración INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES

Magnesium removal from aluminum molten alloys using silica based minerals and waste from coal-fired power (cenospheres)

FERNANDO CARMONA MUÑOZ HECTOR MANUEL HERNANDEZ GARCIA RITA MUÑOZ ARROYO JOSE CONCEPCION ESCOBEDO BOCARDO (2013)

In this work cenospheres, zeolite, silica or mixtures of them were injected

into amolten aluminumalloy using argon as a carrier gas in order tomeasure

their efficiency as Mg removers. The Mg content of the molten alloy was

measured during the injection period and the produced dross was weighted

for each experiment. The physicochemical characterization and the use of

the thermodynamic software FactSage version 6.2, allowed the

determination of the reaction mechanism between the powders and the

molten aluminum. Cenospheres demonstrated their capacity as Mg

removers with an efficiency similar to silica but lower than that

corresponding to zeolite and zeolite:silicamixtures. The use of a zeolite:silica

mixture (65:35wt%) produced the best results, removing the magnesiumof

the alloy from an initial content of 1wt% to a final content of 0.0072wt%

Artículo

Modificación de materiales INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES

Effects of Silicon Nanoparticles on the Transient Liquid Phase Bonding of 304 Stainless Steel

HECTOR MANUEL HERNANDEZ GARCIA RITA MUÑOZ ARROYO JORGE LEOBARDO ACEVEDO DAVILA FELIPE DE JESUS GARCIA VAZQUEZ FELIPE ARTURO REYES VALDES (2014)

Transient liquid phase (TLP) bonding of 304 stainless steel with nickel based filler metal, BNi-9, was performed to

study the influence of silicon nanoparticles (NPs) on the mechanical and structural properties of the bonding area.

It was found that silicon NPs act as a melting point depressant in the brazing process; the formation of silicon TLP

induces the dissolution of elements of the metal filler and promotes a uniform distribution in the bonding area.

Silicon NPs induce the development of smaller eutectic structures in the melting zone; it has been related to

microhardness measurements, which are lower when the silicon NPs are used in the brazing process.

Artículo

Nanopartículas INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA METALÚRGICA

Apparent digestibility coefficient of chickpea, maize, high-quality protein maize, and beans diets in juvenile and adult Nile tilapia (Oreochromis niloticus)

MAGNOLIA MONTOYA MEJIA ALFREDO HERNANDEZ LLAMAS MANUEL GARCIA ULLOA GOMEZ HECTOR GERARDO NOLASCO SORIA ROBERTO GUTIERREZ DORADO HERVEY RODRIGUEZ GONZALEZ (2016)

"The objective of our study was to assess the apparent digestibility of plant ingredients in diets for juvenile (50 g) and adult (220 g) Nile tilapia (Oreochromis niloticus). Dietary dry matter and protein apparent digestibility coefficients of four plant-derived feedstuffs (chickpea, maize, high-quality maize protein, and beans) were tested. The beans diet had the lowest apparent digestibility coefficient of dry matter (ADCDM) (69.41%), while no significant differences were detected in ADCDM among the other diets; ADCDM was significantly higher in adults compared with juveniles (77.02 vs. 73.76%). Apparent dry matter digestibility coefficient of ingredients (ADCI) was significantly higher in the chickpea (70.48%) and high-quality protein maize (71.09%) ingredients, and lower in the beans (52.79%) ingredient. Apparent dry matter digestibility coefficient of ingredients was significantly higher in juveniles compared with adults (72.56 vs. 56.80%). The protein digestibility of diet (ADCCP) was significantly higher in the reference diet (93.68%), while the lowest corresponded to the maize (87.86%) and beans (87.29%) diets. Significantly lower apparent digestibility coefficient of protein (ADCICP ) was obtained with the high quality maize protein (59.11%) and maize (49.48%) ingredients, while higher ADCICP was obtained with the chickpea and beans ingredients (71.31 and 63.89%, respectively). The apparent digestibility coefficient of ingredient crude protein ADCICP was significantly higher in juveniles compared with adults (67.35 vs. 53.46). Digestibility is generally higher in juveniles, and we recommend using chickpea as an ingredient in diets for Nile tilapia."

Artículo

adults, feedstuffs, in vivo digestibility, juveniles, plant ingredients CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS PRODUCCIÓN ANIMAL NUTRICIÓN

Digestibility, growth, blood chemistry, and enzyme activity of juvenile Oreochromis niloticus fed isocaloric diets containing animal and plant by products

MAGNOLIA MONTOYA MEJIA MANUEL GARCIA ULLOA GOMEZ ALFREDO HERNANDEZ LLAMAS HECTOR GERARDO NOLASCO SORIA HERVEY RODRIGUEZ GONZALEZ (2017)

"In this work, we studied the digestibility, growth, blood chemistry, and enzyme activity of Nile tilapia (Oreochromis niloticus) juveniles (0.95±0.18 g) using different animal (fish silage meal, whey meal, bovine blood meal, and red crab meal) and plant (extruded bean, extruded chickpea meal, coconut paste, Jatropha curcas meal, and chickpea meal) dietary byproducts. Nine isocaloric diets (321.92±9.10 kcal g−1) were evaluated for 60 days. The highest digestibility of crude protein values for animal and plant sources were obtained for the whey (93.6) and extruded bean meal (90.5) diets, respectively. The final body weight was higher for the red crab and extruded chickpea meal diets, meanwhile the fish silage and red crab byproducts obtained the highest protein efficiency ratio. Hematocrit was similar among the diets of each byproduct source and presented correlation with growth parameters. The highest glucose, cholesterol, and triglyceride values were obtained for fish silage (138.0, 260.5, and 389.0 mg dL−1, respectively) and whey meal (174.5, 242.3, and 284.0 mg dL−1, respectively) groups. A positive correlation was found between the digestibility of crude protein of ingredients and chymotrypsin activity. Oreochromis niloticus is able to better utilize fish silage, whey, extruded bean, and extruded chickpea byproducts, adjusting its digestive physiology. Such ingredients can be used for formulating cheaper and efficient tilapia diets."

Artículo

alternative byproducts, digestive response, formulated diets, growth performance, Nile tilapia, physiology BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) FISIOLOGÍA ANIMAL

EVALUACIÓN DE LA POBLACIÓN NATURAL Y HABITAT DE PALMA AZUL (Yucca rigida) EN MAPIMI, DURANGO, MÉXICO

[EVALUATION OF NATURAL POPULATIONS AND HABITAT OF BLUE PALM (Yucca rigida) IN MAPIMÍ, DURANGO, MÉXICO]

ARNOLDO FLORES HERNANDEZ JOSE ANTONIO HERNANDEZ HERRERA LUIS MANUEL VALENZUELA NUÑEZ BERNARDO MURILLO AMADOR EDGAR OMAR RUEDA PUENTE JOSE LUIS GARCIA HERNANDEZ HECTOR GENARO ORTIZ CANO (2011)

"El aprovechamiento, conservación y propagación de la palma azul (Yucca rigida) tiene grandes perspectivas en el norte de México, ya que es una especie ornamental importante, endémica de la Comarca Lagunera. Este estudio se realizó en el 2007 en poblaciones naturales de palma azul (Yucca rigida) en el municipio de Mapimí, Durango, México. El objetivo fue caracterizar el hábitat y evaluar la población con base en diferentes altitudes (rodales) detectados, considerando densidad poblacional y las características de altura de planta, número de ramificaciones, diámetro de tallo (área basal), número de frutos por planta, número de semillas por fruto y porcentaje de germinación. Los resultados muestran que Yucca rigida prefiere suelos poco profundos y se encuentra asociada a vegetación desértica rosetófila y micrófila en altitudes de 1200 a 1300 msnm. Se encontró una densidad poblacional de 890 plantas ha-1 y conforme aumenta la altitud del sitio, la altura de planta y el diámetro del tallo (área basal) tienden a incrementar. Se observó un porcentaje reducido de semillas inmaduras, lo que indica que el polinizador tiene buena eficiencia, y aunado a la polinización cruzada favorece la mayor diversidad de estas plantas. Es necesario ampliar las investigaciones que permitan cuantificar el potencial de la planta e implementar actividades de conservación de la variabilidad genética de esta población."

"The improvement, conservation and propagation of Yucca have high perspectives in the North of México; due it is an important ornamental plant, endemic of the Comarca Lagunera. This study was developed in 2007 in natural populations of blue palm (Yucca rigida) in the municipality of Mapimí, Durango, México. The objective was to characterize the habitat and natural populations in different altitude, based on population density and the characteristics of plant height, number of branches, stem diameter, number of fruit per plant, number of seeds per fruit and germination percentage. Results showed that growth of Yucca rigida occurs on shallow soils. It is associated with desert vegetation such as rosetophylla and microphylla, about 1200 to 1300 meter above the sea level. During this study, was found a population density of 890 plants ha-1, and the plant height and stem diameter showed a tendency to increase when the altitude increased. A low percentage of immature seeds were found, showing that the pollinizer has a good efficiency, moreover offer a high biodiversity of plants, due to the crossed pollination, determining the diversity of population. It is necessary to increase the number of researches to quantify the plant potential and to conservation of genetic variability of this population."

Artículo

vegetación, recursos bióticos, zonas desérticas, ecología vegetation, biotic resources, desert zones, ecology CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS AGRONOMÍA PROPAGACIÓN DE VEGETALES

Enhancing Ecoefficiency in Shrimp Farming through Interconnected Ponds

RAMON HECTOR BARRAZA GUARDADO JOSE ALFREDO ARREOLA LIZARRAGA Anselmo Miranda-Baeza MANUEL JUÁREZ GARCÍA RAMÓN CASILLAS HERNÁNDEZ (2015)

"The future development of shrimp farming needs to improve its ecoefficiency. The purpose of this studywas to evaluate water quality, flows, and nitrogen balance and production parameters on a farm with interconnected pond design to improve the efficiency of the semi-intensive culture of Litopenaeus vannamei ponds. The study was conducted in 21 commercial culture ponds during 180 days at densities of 30–35 indm−2 and daily water exchange <2%. Our study provides evidence that by interconnecting ponds nutrient recycling is favored by promoting the growth of primary producers of the pond as chlorophyll 𝑎. Based on the mass balance and flow of nutrients this culture system reduces the flow of solid, particulate organic matter, and nitrogen compounds to the environment and significantly increases the efficiency of water (5 to 6.5m3 kg−1 cycle−1), when compared with traditional culture systems. With this culture system it is possible to recover up to 34% of the total nitrogen entering the system, with production in excess of 4,000 kg ha−1 shrimp. We believe that the production system with interconnected ponds is a technically feasible model to improve ecoefficiency production of shrimp farming."

Artículo

Shrimp, farm BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) DESARROLLO ANIMAL

Efecto de la adición de nanopartículas de tungsteno sobre la microestructura de una aleación base Co unida por el proceso brazing

MARCELA NOHEMI IBARRA CASTRO HECTOR MANUEL HERNANDEZ GARCIA JOSE MANUEL ALMANZA ROBLES RITA MUÑOZ ARROYO PEDRO PEREZ VILLANUEVA FELIPE ARTURO REYES VALDES (2015)

Muestras fracturadas de aleación de cobalto fueron unidas por el proceso brazing con y sin la

impregnación superficial de nanopartículas de tungsteno, con el fin de observar el efecto de

estas nanopartículas sobre la microestructura de la unión. El material de aporte seleccionado

para este trabajo fue la pasta BCo-1, la cual fue caracterizada por Microscopia Electrónica de

Barrido (MEB) y Espectroscopia de Fluorescencia de Rayos-X. Las muestras fracturadas se

generaron a partir de ensayos de flexión de probetas de 10 mm. x 10 mm. x 60 mm. Dichas

fracturas fueron inspeccionadas por MEB. La impregnación de las nanopartículas de tungsteno

se llevó a cabo colocando las muestras fracturadas de cobalto dentro de una mezcla de 0.5 gr.

de las nanopartículas con 100 ml. de etanol, la cual fue colocada en el equipo de ultrasonido

durante 15 minutos. El proceso brazing se realizó en un horno tubular de alta temperatura con

atmosfera de argón a 1200 °C por 60 minutos. Las muestras soldadas fueron observadas en el

Microscopio Óptico y MEB. La interacción de las nanopartículas de tungsteno con el material de

aporte en la zona de fusión modifico el tamaño y la morfología de las fases formadas,

observándose fases con una microestructura más fina y uniformemente distribuida.

Ítem publicado en memoria de congreso

Modificación de materiales por nanopartículas INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES

Co-based alloy brazing incorporating tungsten nanoparticles

MARCELA NOHEMI IBARRA CASTRO HECTOR MANUEL HERNANDEZ GARCIA JOSE MANUEL ALMANZA ROBLES RITA MUÑOZ ARROYO JORGE LEOBARDO ACEVEDO DAVILA CARLOS ALBERTO GUEVARA CHAVEZ LOURDES SANTIAGO BAUTISTA (2015)

Tungsten nanoparticles (NP's) were impregnated in fractured samples of a Co-based alloy in order to evaluate their effect over the microstructure of the joint during a brazing process. The structure and morphology of the tungsten NP's were characterized by high resolution transmission electron microscopy (TEM). The brazing filler metal selected for this work was Nicrobraz 210 and it was characterized by scanning electron microscopy (SEM) and Spectrometry X-Ray Fluorescence. Cracks were generated in Co-based alloy rectangular samples of 10 mm x 10mm x 60 mm by bending them with a mechanical testing machine; these fractures were inspected by SEM. For the impregnation of the cracks with NP's, a mixture of 0.5 g of tungsten NP's in 100 ml of ethanol was sonicated for 15 min. This sonicating time promotes the diffusion of tungsten inside the microcracks. The 210-S filler metal was used in the cracked samples with and without tungsten NP's impregnation. The brazing process was conducted in a sealed tube furnace under an Ar gas flow at 1200 °C for 60 min.Brazed samples were analyzed by optical microscope and SEM. The interaction of tungsten nanoparticles with the metallic filler in the melting zone modified the size and the morphology of the formed phases into a finer and uniformly distributed microstructure.

Artículo

modificación de materiales por nanopartículas INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES