5,613 research outputs found

    Microstructure and Modelling of Shear Forming

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    The advent of multiaxial CNC machines has generated renewed interest in flexible incremental forming manufacturing methodologies, such as shear forming. These processes use rotating tools in constant local contact with the workpiece, which is often also rotating, to generate shape. As a consequence, much lower loads than conventional forming are needed to produce components with no need for expensive special tooling. Potential has already been established by demonstrating manufacture of high-value products, e.g. turbine and satellite parts, with high dimensional accuracy from difficult to manufacture materials. Thus, huge opportunities exist for these processes to replace the current method of manufacture for a range of high value components, e.g. eliminating lengthy machining, reducing material waste and process times; or the manufacture of a complicated shape without the development of expensive tooling. However, little is known about the exact deformation conditions during processing and why certain materials are better than others for shear forming, leading to significant trial and error before production. Three alloys were used for this project: Timetal 54M, Jethete M154 and Inconel 718. General microscopy and Electron Backscatter Diffraction were used to measure strains and orientation maps during shear forming and compared with finite element simulations of the process. It was found that in all cases simple shear deformation was dominate but its extent varied through the thickness, with greater levels of deformation at the roller side. A Design of Experiments analysis was also conducted in order to understand the impact of process parameters in the properties of the final workpieces. Such information was the key to develop a reliable Finite Element Model (FEM) that closely resembles the deformation paths of this process. Three methods of damage calculations were embedded in the finite element model and it was found that the forming limit diagram approach had most potential to identify ultimate failure in shear forming, however its use was still not entirely adequate for this process and a different approach was suggested based on previous works found in the literature. Finally, a methodology to test the potential of materials to be shear spun is proposed based on the finite element model developed and these findings

    Sistema de Informacion que Utiliza Datos del Proceso de Fabricacion de un Controlador Logico Programable

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    En la actualidad, las empresas requieren de la obtención de datos precisos, análisis que apoye en la toma de decisiones y en la mejora continua; estos procesos han llegado a formar parte de la visión de negocios de la gerencia empresarial sobre la cual están orientados los objetivos de negocios para poder ser y permanecer competitivos. Las empresas de manufactura tienen la necesidad de obtener y analizar datos relacionados a los procesos de producción para determinar el nivel de eficiencia de estos y en base a la información obtenida tomar decisiones que ayuden a la empresa a mejorar o corregir situaciones que puedan ser de carácter humano, operativo, procedural o de equipo. En este proyecto de desarrollo de software se ha diseñado e implementado un sistema de información, con el método de cascada, para una empresa de manufactura localizada en la frontera norte de México con Estados Unidos en el sector del cuidado de la salud; el sistema utiliza datos desde un controlador lógico programable, en el cual se obtienen datos para su monitoreo como: alarmas de la máquina, conteo de eventos, duración de cada alarma y velocidad de producción. Dando como resultado información de los códigos de producción, turno, día y hora; además de medir de forma precisa la eficiencia de la máquina, así como la detección de tendencias y la creación de alertas oportunas hacia personas técnicas para la solución de problemas. El sistema consta de un análisis de velocidad y carga de trabajo del procesador del PLC, desarrollo de la conexión entre el procesador y el sistema, preparación del sistema para el traspaso de información, programación de la base de datos en Access y el diseño de la interfaz gráfica en Visual Basic. Net. Entre los logros más importantes obtenidos de la implementación del sistema de información se encuentran: Disponibilidad de la información en tiempo real y obtención de datos históricos de las variables de producción del equipo, mejoramiento de las tareas de supervisión y control de procesos, así como el envío de alertas a usuarios específicos para reacción adecuada a eventos de fallas.   Currently, companies require obtaining accurate data, analysis that supports decision-making and continuous improvement; these processes have become part of the business management vision on which business objectives are oriented to be and remain competitive. Manufacturing companies have the need to obtain and analyze data related to production processes to determine their level of efficiency and based on the information obtained, make decisions that help the company improve or correct situations that may be of human, operational, procedural or equipment. In this software development project, with the cascade method, an information system has been designed and implemented, for a manufacturing company located on the northern border of Mexico with the United States in the health care sector; the system uses data from a programmable logic controller, in which data such as: machine alarms, event count, duration of each alarm, and production speed were obtained for monitoring. Resulting in information on the production codes, shift, day and hour; in addition to accurately measuring the efficiency of the machine, as well as the detection of trends and the creation of timely alerts to technical personnel for troubleshooting. The system consists of an analysis of the speed and workload of the PLC processor, development of the connection between the processor and the system, preparation of the system for the transfer of information, programming of the database and the design of a graphical interface in Visual Basic.Net . Among the most important achievements obtained from the implementation of the information system are: Availability of information in real time and obtaining historical data from production variables, improvement of supervision tasks and process control, as well such as sending alerts to specific users for adequate reaction to failure events

    Dark fermentative hydrogen production: from concepts to a sustainable production

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    ABSTRACT: The use of renewable sources and environmentally friendly processes is considered a priority for the construction of a sustainable energy future. The harmful impact of fossil fuels and the fact that we are reaching a disrupting point regarding environmental damage require the rapid implementation of new energy systems and a substantial increase in the use of alternative, unconventional energy sources. Hydrogen (H2) is considered one of the most promising sources as a clean energy vector, because of its high energy density (120 MJ/kg) and carbon-free combustion (Argun and Kargi, 2011). Hydrogen is the simplest and most abundant element on earth; however, it barely exists in nature in its molecular state. Instead, it is almost always found as part of other compounds from which it should be separated, either by thermochemical processes or through biological conversion.info:eu-repo/semantics/publishedVersio

    Efecto de seis dietas en el crecimiento y supervivencia de poslarvas de abulón rojo (Haliotis rufescens) y su híbrido (H. rufescens ♀ × H. fulgens ♂)

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    One of the main bottlenecks in abalone aquaculture is maintaining individuals during the weaning stage, when the natural diet changes from diatoms (postlarvae) to macroalgae (juvenile). During this period, abalone pass through profound morphological and physiological changes, which suitable nutrient requirements must sustain. An inadequate diet can result in adverse effects such as late metamorphosis, starvation, slow growth and even death during this phase. Two strategies have been proposed to increase the growth and survival rates of weaning abalone: (i) extending feeding with benthic diatoms and (ii) abalone hybridization via interspecific crosses. To evaluate the efficiency of the two strategies, we assessed the growth and survival rates of postlarvae of pure red abalone (Haliotis rufescens) and a hybrid obtained by crossing red abalone females with green abalone (H. fulgens) males. Both crosses were supplied with six different diets consisting of either one macroalgae mono-diet (Macrocystis pyrifera or Ulva ohnoi) or a mixture with Navicula incerta. Overall, cross-specific diets achieved better growth rates, suggesting that each cross may need specific food items (nutrients) during weaning. Moreover, pure red abalone generally showed the highest growth rates, while the hybrid abalone showed the highest survival rates with most tested diets. Hence, hybrids appear to be better at withstanding stressful conditions, and their use in aquaculture could reduce losses and increase commercial production.   Uno de los principales cuellos de botella en la acuicultura de abulón es el mantenimiento de los individuos durante la fase de destete, cuando la dieta natural cambia de diatomeas (postlarvas) a macroalgas (juveniles). Durante este período, el abulón pasa por profundos cambios morfológicos y fisiológicos, que deben ser sostenidos por una alimentación adecuada. Una dieta inadecuada puede provocar efectos adversos como: metamorfosis tardía, inanición, crecimiento lento e incluso la muerte durante esta fase. Por ello, se han propuesto dos estrategias para aumentar las tasas de crecimiento y supervivencia del abulón durante la fase de destete: (i) ampliar el período de alimentación con diatomeas bentónicas y (ii) la hibridación de abulones mediante cruces interespecíficos. Para determinar la eficacia de ambas estrategias, se evaluaron las tasas de crecimiento y supervivencia de postlarvas de abulón rojo puro (Haliotis rufescens) y de un híbrido obtenido mediante el cruce de hembras de abulón rojo y machos de abulón azul (H. fulgens). A ambos cruces se les suministraron seis dietas diferentes consistentes en una mono dieta de macroalgas (Macrocystis pyrifera, Ulva ohnoi) o en una mezcla con Navicula incerta. En general, con las dietas específicas para cada cruce se obtuvieron mejores tasas de crecimiento, lo que sugiere que cada cruce requiere alimentos (nutrientes) específicos durante el destete. Además, el abulón rojo puro mostró en general las tasas de crecimiento más altas, mientras que en el abulón híbrido se obtuvieron las mayores tasas de supervivencia con la mayoría de las dietas probadas. Por lo que los híbridos parecen soportar mejor las condiciones de estrés, y su uso en la acuicultura podría ayudar a reducir las pérdidas y aumentar su producción comercial

    Efecto de la temperatura y tiempo de almacenamiento en la concentración de algunas fitohormonas y germinación de las semillas del chile piquín Capsicum annuum var. glabriusculum (Dunal) Heiser & Pickersgill

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    The genus Capsicum is an economically important plant around the world. In Mexico, chili cropping is a profitable agricultural business due to its demand in the national and international market. A species of interest is the bird pepper, Capsicum annuum var. glabriusculum (Dunal) Heiser & Pickersgill, whose exploitation is limited only to wild populations. There have been many unsuccessful attempts to cultivate it intensively because of its low germination percentage, since the seed shows non-deep physiological dormancy, a frequent feature in undomesticated wild species. In this study, the effect of temperature and age of bird pepper seed on the concentration of auxins (tryptophan), cytokinins (kinetin) and gibberellins (GA3) and their germinative capacity were analyzed. For this, the germinative capacity of pepper seeds stored at two temperatures (4 and 24°C) and five ages (0, 3, 6, 9 and 12 months) was evaluated. Also, quantification of the phytohormones auxins, cytokinins and gibberellins was performed using high performance liquid chromatography (HPLC). The results show that the content of the three phytohormones had increased through time according to the time of storage (p≤0.05). The highest germination percentage was at 9 months of storage (p≤0.05) and this was the highest content of the three phytohormones; therefore at this age, the seed reached its maturation point; however, at 12 months of storage, germination started diminishing as well as the phytohormone content, indicating that the seed quality and viability was starting to decrease.El género Capsicum es una hortaliza de importancia económica a nivel mundial. En México es una importante actividad económica en el sector agrícola, por ello la importancia del cultivo de variedades que permitan abrir nuevas áreas de oportunidad comercial tanto a nivel nacional como internacional. Una de estas variedades es el chile piquín Capsicum annuum var. glabriusculum (Dunal) Heiser & Pickersgill, cuyo aprovechamiento se reduce únicamente a poblaciones silvestres, ya que se han hecho varios intentos de cultivarla de manera intensiva teniendo como resultado bajos porcentajes de germinación, debido a que la semilla presenta latencia fisiológica no profunda, rasgo característico de especies que aún no han sido domesticadas. En este estudio se propuso conocer el efecto de la temperatura y el tiempo de almacenamiento, sobre el contenido de triptófano (aminoácido precursor de auxinas), citocininas (kinetina) y giberelinas (GA3) presentes en la semilla y su relación en el proceso de germinación. Para evaluar la capacidad de germinación de las semillas de chile piquín, estas se almacenaron a dos temperaturas (4 °C y 24 °C) y cinco tiempos de almacenamiento (0, 3, 6, 9 y 12 meses). Además, se cuantificó el contenido de fitohormonas, auxinas, citicininas y giberelinas utilizándose la técnica de Cromatografía Líquida de Alta Resolución (HPLC). Los resultados muestran que el contenido de las tres fitohormonas se incrementó con respecto al tiempo de almacenamiento. El más alto porcentaje de germinación y concentración de fitohormonas se presentó a los 9 meses de almacenamiento; mientras que, a los 12 meses, la germinación empieza a disminuir, así como el contenido de fitohormonas, indicando que la calidad y viabilidad de la semilla ha empezado a decrecer

    Differences Between Intact and Ovariectomized Hemiparkinsonian Rats in Response to L-DOPA, Melatonin, and L-DOPA/Melatonin Coadministration on Motor Behavior and Cytological Alterations

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    Parkinson?s disease (PD) higher incidence has been observed in postmenopausal women compared to premenopausal women, suggesting estrogen neuroprotective effect. L-DOPA (LD) chronic treatment causes dyskinesia; evidences indicate that LD increases the preexisting oxidative stress condition. This study determines melatonin ability, alone or in combination with LD (LD/Mel) to protect dopaminergic loss induced by 6-OHDA in a rat PD model in ovariectomized (OVX) and intact (with ovaries (W/OV)) rats on motor behavior and cytological alterations, comparing with LD-only treated rats. LD/Mel-treated rats showed dyskinesia decrease (score 5–7.5) and had the best performance in the staircase test (five pellets) throughout all studies. The beam walking time was 20–35 s, showing good coordination (as control group (20–38 s)), dopaminergic cells increase of 22.8% (W/OV rats) and 27.2% (OVX rats) in the contralateral side as well as 100% conservation in the contralateral dendritic spines. Our results suggest that LD/Mel co-administration and estrogen presence result in an efficient treatment to reduce dyskinesia through the conservation of some dopaminergic cells, which imply a well-preserved neuropil of a less denervated striatum. We assume that these results are because of a synergistic effect between LD, melatonin and estrogens

    Description of Genetic Variants in BRCA Genes in Mexican Patients with Ovarian Cancer: A First Step towards Implementing Personalized Medicine

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    Abstract Gynecologic cancers are among the leading causes of death worldwide, ovarian cancer being the one with the highest mortality rate. Olaparib is a targeted therapy used in patients presenting mutations in BRCA1 and BRCA2 genes. The aim of this study was to describe BRCA1 and BRCA2 gene variants in Mexican patients with ovarian cancer. Sequencing of BRCA1 and BRCA2 genes from tumors of 50 Mexican patients with ovarian cancer was made in a retrospective, non-randomized, and exploratory study. We found genetic variants in 48 of 50 cases. A total of 76 polymorphic variants were found in BRCA1, of which 50 (66%) had not been previously reported. Furthermore, 104 polymorphic variants were found in BRCA2, of which 63 (60%) had not been reported previously. Of these polymorphisms, 5/76 (6.6%) and 4/104 (3.8%) were classified as pathogenic in BRCA1 and BRCA2, respectively. We have described the genetic variants in BRCA1 and BRCA2 of tumors from Northeast Mexican patients with sporadic ovarian cancers. Our results showed that the use of genetic testing helps recognize patients that carry pathogenic variants which could be beneficial for personalized medicine treatments. Keywords: BRCA; ovarian cancer; personalized therapy; sequencin

    DIMENSIONAMIENTO DE CRISTALES DE AZÚCAR A PARTIR DE PROCESAMIENTO DE IMÁGENES (SIZING OF SUGAR CRYSTALS BY IMAGE PROCESSING)

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    Resumen En este trabajo se determinaron las áreas superficiales y los volúmenes de cristales de azúcar capturados en un microscopio. El área superficial se determina a partir del análisis de imágenes, para ello se determinan los bordes de los cristales que se muestren completos y ortorrómbicos en la pantalla. Con la determinación de las áreas de los cristales se crea una relación dentro del programa para generar el valor del volumen. El procesamiento aquí mostrado puede ser empleado en línea o procesando un video pregrabado. En este caso, para grabar se utilizó un celular que grababa a través de la mirilla de un microscopio mientras los cristales pasabas por una celda de cristal. El análisis cuenta con un error del 0.8016% en comparación al método mie, utilizado en un MasterSizer. Palabras clave: Procesamiento imagen, cristales, dimensionamiento. Abstract In this work, the surface areas and volumes of sugar crystals captured under a microscope were determined. The surface area is determined from image analysis by determining the edges of the crystals that appear complete and orthorhombic on the screen. With the determination of the crystal areas a relation is created within the program to generate the volume value. The processing shown here can be employed online or by processing a pre-recorded video. In this case, a cell phone was used to record through a microscope scope while the crystals were passing through a crystal cell. The analysis has an error of 0.8016% compared to the mie method used in MasterSizer. Keywords: Image processing, crystals, sizing.>/em

    Vejez y vulnerabilidad. Retratos de casos y perfiles de estudio en contextos diversos: grandes regiones, localidades rurales y territorios migrantes

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    México está inmerso en una acelerada transición demográfica, es el séptimo lugar entre los países con envejecimiento acelerado en Latinoamérica, con 9.7% de adultos mayores de 60 años (CONAPO, 2013). La investigación en nuestro país en torno a los sectores envejecidos tiene ya más de un cuarto de siglo, y ha contribuido al desarrollo de los estudios sobre este grupo de la población bajo las tendencias no sólo locales y regionales, sino también internacionales; respondiendo a las necesidades sociales que se modifican a través de la historia.Desde el área de especialización de cada autor, se pone particular atención en las condiciones de la vida cotidiana y las estrategias que se generan para enfrentar y reducir la vulnerabilidad, así como en los retos que se afrontarán por e l tendiente proceso de envejecimiento de la población, principalmente en los ámbitos socioculturales y de salud.Universidad Autónoma del Estado de Méxic

    ROCK Inhibitor Y-27632 Suppresses Dissociation-Induced Apoptosis of Murine Prostate Stem/Progenitor Cells and Increases Their Cloning Efficiency

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    Activation of the RhoA/ROCK signaling pathway has been shown to contribute to dissociation-induced apoptosis of embryonic and neural stem cells. We previously demonstrated that approximately 1 out of 40 Lin−Sca-1+CD49fhigh (LSC) prostate basal epithelial cells possess the capacities of stem cells for self-renewal and multi-lineage differentiation. We show here that treating LSC cells with the ROCK kinase inhibitor Y-27632 increases their cloning efficiency by 8 fold in an in vitro prostate colony assay. Y-27632 treatment allows prostate colony cells to replate efficiently, which does not occur otherwise. Y-27632 also increases the cloning efficiency of prostate stem cells in a prostate sphere assay and a dissociated prostate cell regeneration assay. The increased cloning efficiency is due to the suppression of the dissociation-induced, RhoA/ROCK activation-mediated apoptosis of prostate stem cells. Dissociation of prostate epithelial cells from extracellular matrix increases PTEN activity and attenuates AKT activity. Y-27632 treatment alone is sufficient to suppress cell dissociation-induced activation of PTEN activity. However, this does not contribute to the increased cloning efficiency, because Y-27632 treatment increases the sphere-forming unit of wild type and Pten null prostate cells to a similar extent. Finally, knocking down expression of both ROCK kinases slightly increases the replating efficiency of prostate colony cells, corroborating that they play a major role in the Y-27632 mediated increase in cloning efficiency. Our study implies that the numbers of prostate cells with stem/progenitor activity may be underestimated based on currently employed assays, supports that dissociation-induced apoptosis is a common feature of embryonic and somatic stem cells with an epithelial phenotype, and highlights the significance of environmental cues for the maintenance of stem cells
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