Active vibration control in building-like structures submitted to earthquakes using multiple positive position feedback and sliding modes

This work deals with the structural and dynamic analysis of a building-like structure consisting of a three-story building with one passive/active vibration absorber. The base of the structure is perturbed using a shaker, providing excitation forces and noisy excitations emulating ground transportation, underground railways and earthquakes, quite common in Mexico City. It is considered a realistic seismic record of 8.1Mw occurred at Mexico City, containing some resonant frequencies of the structure. The mechanical structure is modeled using Euler-Lagrange methodology and validated using experimental modal analysis techniques. The active control scheme is synthesized to actively attenuate the noise and vibration system response, caused by noisy excitation forces acting on the base, by employing Multiple Positive Position Feedback and Sliding Mode Control to improve the closed-loop system response and, simultaneously, attenuate three vibration modes. Simulation and experimental results describe the overall system performance

Dendritic Cells: Location, Function, and Clinical Implications

Dendritic cells (DCs) are antigen-presenting cells derived from bone marrow precursors and form a widely distributed cellular system throughout the body. DCs exert immune-surveillance for exogenous and endogenous antigens and the later activation of naive T lymphocytes giving rise to various immunological responses. Different growth factors and cytokines can modulate the differentiation and function of DCs, GM-CSF, M-CSF, Flt3, and TGF-β, resulting in a large variety of DCs with different functional abilities. Thus, DCs are classified as plasmacytoid DCs (pDCs), conventional DCs (cDCs), and DCs derived from monocytes (mDCs). Functionally, the cDCs may be divided into two states: immature and mature. Immature DCs are specialist in uptaking and processing antigens; in contrast, mature DCs are professional in antigen presentation. It has been observed that immature cDCs can induce immune tolerance while mature cDCs may induce Th2 or Th1 immune responses. It is worth noting that different subpopulations of DCs have the ability to secrete different cytokine patterns, resulting in the induction of different immunological responses. Furthermore DCs are involved in the pathophysiology of several diseases such as contact hypersensitivity, autoimmune diseases, or cancer, but they can also be used as therapeutic tools in these conditions

Enhancing dendritic cell immunotherapy for melanoma using a simple mathematical model

ABSTRACT Background: The immunotherapy using dendritic cells (DCs) against different varieties of cancer is an approach that has been previously explored which induces a specific immune response. This work presents a mathematical model of DCs immunotherapy for melanoma in mice based on work by Experimental Immunotherapy Laboratory of the Medicine Faculty in the Universidad Autonoma de Mexico (UNAM). Method: The model is a five delay differential equation (DDEs) which represents a simplified view of the immunotherapy mechanisms. The mathematical model takes into account the interactions between tumor cells, dendritic cells, naive cytotoxic T lymphocytes cells (inactivated cytotoxic cells), effector cells (cytotoxic T activated cytotoxic cells) and transforming growth factor β cytokine (TGF − β). The model is validated comparing the computer simulation results with biological trial results of the immunotherapy developed by the research group of UNAM. Results: The results of the growth of tumor cells obtained by the control immunotherapy simulation show a similar amount of tumor cell population than the biological data of the control immunotherapy. Moreover, comparing the increase of tumor cells obtained from the immunotherapy simulation and the biological data of the immunotherapy applied by the UNAM researchers obtained errors of approximately 10 %. This allowed us to use the model as a framework to test hypothetical treatments. The numerical simulations suggest that by using more doses of DCs and changing the infusion time, the tumor growth decays compared with the current immunotherapy. In addition, a local sensitivity analysis is performed; the results show that the delay in time “τ ”, the maximal growth rate of tumor “r” and the maximal efficiency of tumor cytotoxic cells rate “aT” are the most sensitive model parameters. Conclusion: By using this mathematical model it is possible to simulate the growth of the tumor cells with or without immunotherapy using the infusion protocol of the UNAM researchers, to obtain a good approximation of the biological trials data. It is worth mentioning that by manipulating the different parameters of the model the effectiveness of the immunotherapy may increase. This last suggests that different protocols could be implemented by the Immunotherapy Laboratory of UNAM in order to improve their results

Chiapas : entre el autoritarismo y la transición democrática, desde Acteal hasta el diálogo EZLN y sociedad civil

Obra cuya intención es dar cuenta de los diversos actores sociales involucrados en el conflicto de Chiapas, a nivel político, económico y sociocultural. El texto recupera un taller de análisis de coyuntura sobre el tema, realizado en agosto de 1998.ITESO, A.C

Post-Franco Theatre

In the multiple realms and layers that comprise the contemporary Spanish theatrical landscape, “crisis” would seem to be the word that most often lingers in the air, as though it were a common mantra, ready to roll off the tongue of so many theatre professionals with such enormous ease, and even enthusiasm, that one is prompted to wonder whether it might indeed be a miracle that the contemporary technological revolution – coupled with perpetual quandaries concerning public and private funding for the arts – had not by now brought an end to the evolution of the oldest of live arts, or, at the very least, an end to drama as we know it

Analysis and Detection of Erosion in Wind Turbine Blades

This paper studies erosion at the tip of wind turbine blades by considering aerodynamic analysis, modal analysis and predictive machine learning modeling. Erosion can be caused by several factors and can affect different parts of the blade, reducing its dynamic performance and useful life. The ability to detect and quantify erosion on a blade is an important predictive maintenance task for wind turbines that can have broad repercussions in terms of avoiding serious damage, improving power efficiency and reducing downtimes. This study considers both sides of the leading edge of the blade (top and bottom), evaluating the mechanical imbalance caused by the material loss that induces variations of the power coefficient resulting in a loss in efficiency. The QBlade software is used in our analysis and load calculations are preformed by using blade element momentum theory. Numerical results show the performance of a blade based on the relationship between mechanical damage and aerodynamic behavior, which are then validated on a physical model. Moreover, two machine learning (ML) problems are posed to automatically detect the location of erosion (top of the edge, bottom or both) and to determine erosion levels (from 8% to 18%) present in the blade. The first problem is solved using classification models, while the second is solved using ML regression, achieving accurate results. ML pipelines are automatically designed by using an AutoML system with little human intervention, achieving highly accurate results. This work makes several contributions by developing ML models to both detect the presence and location of erosion on a blade, estimating its level and applying AutoML for the first time in this domain

Uso de técnicas de pronósticos para la planeación del inventario de una PYME comercializadora en Tlaxcala, México

This paper aims to provide forecasting tools that could assist the manager of the SME under analysis to anticipate future sales and make better purchasing decisions that improve inventory levels. The subject of the case study was a retail shop selling construction materials in Tlaxcala. On account of its contribution to 50% of the business´ global profits, we used historical data of Portland cement sales. A comparison was performed among simple heuristics observed in the local environment (the weekly average of the last year, the weekly average of the previous month, and the same amount as the previous week) and forecasting techniques usually applied in the literature (simple linear regression, exponential smoothing, non-linear regression, and regression by neural networks). The results revealed that any forecasted value close, or equal to the mean will be acceptable when the data series follows a normal distribution. It was found that the non-linear model (natural logarithmic regression) fitted the data better due to the variable nature of the demand, the forecasts with values ​​close to the mean, and 88% of correct answers in the trend pattern.La presente investigación tiene como objetivo contribuir con herramientas de pronósticos que asistan al administrador de la PYME bajo análisis a anticipar las ventas futuras para tomar decisiones de compra más acertadas que optimicen los niveles de inventario. El estudio se realiza en una empresa comercializadora de materiales de construcción en Tlaxcala, utilizando los datos históricos de venta del cemento gris por su aportación al 50% de las utilidades globales del negocio. Se compararon tres prácticas observadas en el entorno local (promedio semanal del último año, promedio semanal del mes anterior y misma cantidad que la semana anterior) y cinco técnicas de pronósticos usualmente aplicadas en la literatura (regresión lineal simple, suavización exponencial, regresión no lineal, regresión por redes neuronales y metodología Box-Jenkins). Los resultados revelaron que, cualquier pronóstico cercano o igual a la media resultará aceptable cuando la serie de datos siga una distribución normal. Hallándose que el modelo no lineal (regresión logarítmica natural) se ajustó mejor a los datos por la naturaleza variable de la demanda, los pronósticos con valores cercanos a la media y el 88% de aciertos en el patrón de tendencia

Aplicación de metodología Lean Manufacturing para reducir costos en almacén de la empresa Energía y Fluidos Perú SAC. Lima, 2020

La presente tesis titulada "Aplicación de metodología Lean Manufacturing para reducir costos en almacén de la empresa Energía y Fluidos Perú S.A.C. Lima, 2020", tiene como objetivo principal determinar la influencia del método Lean Manufacturing en la reducción de costos existentes del almacén buscando cumplirlo haciendo uso de la metodología lean, con el fin de poder reducir costos. Este estudio es de tipo aplicada, de enfoque cuantitativo, alcance explicativo, siguiendo el diseño experimental-cuasiexperimental y longitudinal. La muestra es de tipo no probabilístico por conveniencia, recopilados en 16 semanas pre y 16 post test. La técnica para la recolección de datos fue el análisis documental; el instrumento fue el registro tecnológico e información del registro de compras, costos por alquiler de infraestructura, entre otros. Analizamos los datos empleando formulas planteadas en los indicadores utilizando Microsoft Excel-2020 y SPSS version-25, de manera inferencial y descriptivo, pudiendo verificar que las dimensiones evaluadas reducen considerablemente al igual que el CTM y el CTP. La prueba de Wilcoxon acepta que la metodología utilizada influye en los costos de almacen, concluyendo que haciendo uso de las 5s se redujo en S/. 144.73 el CTM y del CTP de S/. 2456.06 a S/. 1694.19

Jacinto de agua, alternativa para el tratamiento de agua dulce en producción agrícola

En este documento se presenta el estudio del tratamiento de agua dulce utilizando jacinto de agua (eichhornia cassipes) llevado a cabo en trabajos realizados en la provincia del guayas y el oro en la que se utilizaron plantas flotantes como filtros biológicos para controlar la calidad del agua. En este ensayo se utilizaron 9 piscinas de 0.3 ha. Destinadas al cultivo de langosta australiana. Se realizaron mediciones de parámetros necesarios para controlar la calidad del agua como oxígeno, temperatura y amonio y evaluaciones de la producción de juveniles de langosta. Las piscinas con lechuguín mostraron niveles de amonio más bajo en relación a los controles de igual manera el oxígeno se mantuvo más estable durante toda la prueba en las piscinas de tratamiento que en los controles. La producción de juveniles/ha/día fue mejor en las piscinas que tenían lechuguín en las esquinas que en el resto de piscinas