927 research outputs found
Energy efficiency in discrete-manufacturing systems: insights, trends, and control strategies
Since the depletion of fossil energy sources, rising energy prices, and governmental regulation restrictions, the current manufacturing industry is shifting towards more efficient and sustainable systems. This transformation has promoted the identification of energy saving opportunities and the development of new technologies and strategies oriented to improve the energy efficiency of such systems. This paper outlines and discusses most of the research reported during the last decade regarding energy efficiency in manufacturing systems, the current technologies and strategies to improve that efficiency, identifying and remarking those related to the design of management/control strategies. Based on this fact, this paper aims to provide a review of strategies for reducing energy consumption and optimizing the use of resources within a plant into the context of discrete manufacturing. The review performed concerning the current context of manufacturing systems, control systems implemented, and their transformation towards Industry 4.0 might be useful in both the academic and industrial dimension to identify trends and critical points and suggest further research lines.Peer ReviewedPreprin
Economic model predictive control for optimal operation of combined heat and power systems
© 2019. ElsevierThe use of decentralized Combined Heat and Power (CHP) plants is increasing since the high levels of efficiency they can achieve. Hence, to determine the optimal operation of these systems in the changing energy market, the time-varying price profiles for both electricity as well as the required resources and the energy-market constraints should be considered into the design of the control strategies. To solve these issues and maximize the profit during the operation of the CHP plant, this paper proposes an optimization-based controller, which will be designed according to the Economic Model Predictive Control (EMPC) approach. The proposed controller is designed considering a non-constant time step to get a high sampling frequency for the near instants and a lower resolution for the far instants. Besides, a soft constraint to met the market constraints for the sale of electric power is proposed. The proposed controller is developed based on a real CHP plant installed in the ETA research factory in Darmstadt, Germany. Simulation results show that lower computational time can be achieved if a non-constant step time is implemented while the market constraints are satisfied.Peer ReviewedPostprint (author's final draft
Optimal operation of combined heat and power systems: an optimization-based control strategy
The use of decentralized Combined Heat and Power (CHP) plants is increasing since the high levels of efficiency they can achieve. Thus, to determine the optimal operation of these systems in dynamic energy-market scenarios, operational constraints and the time-varying price profiles for both electricity and the required resources should be taken into account. In order to maximize the profit during the operation of the CHP plant, this paper proposes an optimization-based controller designed according to the Economic Model Predictive Control (EMPC) approach, which uses a non-constant time step along the prediction horizon to get a shorter step size at the beginning of that horizon while a lower resolution for the far instants. Besides, a softening of related constraints to meet the market requirements related to the sale of electric power to the grid point is proposed. Simulation results show that the computational burden to solve optimization problems in real time is reduced while minimizing operational costs and satisfying the market constraints. The proposed controller is developed based on a real CHP plant installed at the ETA research factory in Darmstadt, Germany.Peer ReviewedPostprint (author's final draft
An optimization-based control strategy for energy efficiency of discrete manufacturing systems
In order to reduce the global energy consumption and avoid highest power peaks during operation of manufacturing systems, an optimization-based controller for selective switching on/off of peripheral devices in a test bench that emulates the energy consumption of a periodic system is proposed. First, energy consumption models for the test-bench devices are obtained based on data and subspace identification methods. Next, a control strategy is designed based on both optimization and receding horizon approach, considering the energy consumption models, operating constraints, and the real processes performed by peripheral devices. Thus, a control policy based on dynamical models of peripheral devices is proposed to reduce the energy consumption of the manufacturing systems without sacrificing the productivity. Afterward, the proposed strategy is validated in the test bench and comparing to a typical rule-based control scheme commonly used for these manufacturing systems. Based on the obtained results, reductions near 7% could be achieved allowing improvements in energy efficiency via minimization of the energy costs related to nominal power purchased.Peer ReviewedPostprint (author's final draft
Cardiopulmonary resuscitation in prone position and COVID-19
Los pacientes con infección grave por COVID-19 requieren frecuentemente estar en posición decúbito prono 1 Además, estos pacientes con ventilación mecánica tienen más requerimiento de soporte vasopresor (95,4 % vs. 1,5 %) y mayor riesgo de arritmias auriculares (17,7 % vs. 1,9 %) 2. Un estudio en Wuhan, China, informó que el 17,9 % sufrió paro cardiaco intrahospitalario; los ritmos de paro fueron asistolia (89,7 %), actividad eléctrica sin pulso (4,4 %) y ritmos desfibrilables (5,9 %) 3 Con el fin de disminuir los efectos hemodinámicos secundarios a los cambios de posición 4, se sugiere realizar maniobras de reanimación cardiopulmonar (RCP) en prono (RCP invertida) 5; esta técnica, descrita en 1989 por McNeil, ha demostrado ser exitosa 6,7 efectuando las compresiones precordiales inversas con la velocidad y amplitud usualPatients with severe COVID-19 infection frequently require to be in prone position. 1 Furthermore, these patients with mechanical ventilation need additional vasopressor support (95.4 % vs. 1.5 %) and exhibit a higher risk of developing atrial arrhythmias (17.7 % vs. 1.9 %). 2 A study conducted in Wuhan, China, reported that 17.9 % of the patients experienced intrahospital cardiac arrest; the arrest rhythms were asystole (89.7 %), pulseless electrical activity (4.4 %) and defibrillatable rhythms (5.9 %). 3 In order to reduce the hemodynamic effects secondary to changes in position 4 cardiopulmonary resuscitation (CPR) maneuvers in prone position are recommended (inverted CPR) 5; this technique was described in 1989 by McNeil, and has proven to be successful 6,7 doing the inverse precordial compressions at the usual rate and amplitudeRevista Nacional - Indexad
Caracterización del Programa de Campesino a Campesino (PCaC) de la UNAG en las Estrategias de Reproducción de las Unidades Domesticas Campesinas, en el municipio San Dionisio, 2009
La presente investigación se realizó en las 23 comunidades afiliadas al Programa PCaC de UNAG, ubicadas en el Municipio de San Dionisio en el departamento de Matagalpa durante el año 2009, tomando como parámetro de medición los componentes del Programa PCaC san Dionisio y las estrategias de reproducción campesina. El propósito de la presente investigación consistió en caracterizar del Programa de Campesino a Campesino (PCaC) en las Estrategias de Reproducción de las Unidades Domesticas Campesinas, Municipio San Dionisio, 2009. Para ello fue necesario Caracterizar los componentes del Programa de Campesino a Campesino aplicados a Unidades Domésticas Campesinas y luego identificar las Estrategias de Reproducción de las Unidades Domésticas Campesinas afiliados al PCaC. El estudio se aborda desde la perspectiva de los tipos de estudio descriptivos-transversales, con la aplicación de un diseño de investigación de campo donde la población estuvo formada por 683 familias, de las cuales se tomo una muestra quedando un tamaño muestral de 88 productores. Los resultados obtenidos de este estudio beneficiarán al Programa de Campesino a Campesino, a las 23 comunidades en estudio como base de información y planificación de proyectos sociales; a estudiantes y docentes como un material de investigación de igual forma a instituciones interesadas con el tema. Con el estudio se determino que el Programa PCaC tiene mayor incidencia en las estrategias agrícola a través de sus componentes el 70% de los productores trabajan en actividades agrícola
Responsabilidad patrimonial de la dministración sanitaria. Especial referencia a los daños causados durante la pandemia COVID-19
La responsabilidad patrimonial de la Administración Pública se configura
principalmente en el Ordenamiento Jurídico español a través de dos
referencias normativas. En primer lugar, el artículo 106.2 de la Constitución
Española y, por otro lado, el Capítulo IV de la Ley 40/2015, de Régimen
Jurídico del Sector Público.
De otra parte, el procedimiento a seguir para exigir esta responsabilidad, se
encuentra regulado en la Ley 39/2015, de Procedimiento Administrativo
Común de las Administraciones Públicas. Sin embargo, sus elementos
definitorios no encuentran un mayor desarrollo normativo.
Es por ello que el presente proyecto se centra en su interpretación doctrinal
y jurisprudencial para tratar de analizar en profundidad cada uno de sus
elementos configuradores.
Finalmente, este estudio contiene una breve reflexión sobre los
fallecimientos sucedidos durante la pandemia del COVID-19 bajo el ámbito
competencial de las autoridades sanitarias, como consecuencia de la falta de
medios y organización, y la posible responsabilidad patrimonial de las
mismas debido a la gestión realizada.Patrimonial responsibility of Public Administration is configured mainly in
the Spanish Legal System through two normative references. First, article
106.2 of the Spanish Constitution and, on the other hand, Chapter IV of Law
40/2015, on the Legal Regime of the Public Sector.
Also, the procedure to follow to demand this responsibility is regulated in
Law 39/2015, of Common Administrative Procedure of Public
Administrations. However, its defining elements do not find further
normative development.
That is why this project focuses on its doctrinal and jurisprudential
interpretation to try to analyze in depth each of its shaping elements.
Finally, this study contains a brief reflection on the deaths that occurred
during the COVID-19 pandemic under the jurisdiction of the health
authorities, as a consequence of the lack of means and organization, and the
possible patrimonial responsibility of Public Administration due to the
management done
Eficacia de los programas de intervención dirigidos a los/las cuidadores/as familiares de personas con la enfermedad de Alzheimer: una revisión sistemática
La enfermedad de Alzheimer (EA) está presente en millones de
personas en el mundo, originando un gran impacto no solo en la población que
la tiene sino también en sus cuidadores familiares, provocándoles problemas
de salud físicos y psicológicos relativos a su rol. Por esta razón, es importante
velar porque tengan una adecuada calidad de vida. Esta revisión sistemática
pretende examinar la eficacia de los diferentes programas de intervención
dirigidos a la mejora del bienestar de los cuidadores familiares de las personas
con EA. El presente análisis se ha basado en 20 estudios que cumplen con los
criterios de inclusión establecidos previamente y han sido seleccionados de las
bases de datos “PsycINFO (EBSCO)”, “PsycArticles” y “PubMed”. Como
resultado, se ha comprobado que las intervenciones llevadas a cabo en los
estudios analizados han obtenido resultados positivos en la mejora de la
calidad de vida de los cuidadores, siendo las cognitivo – conductuales las más
efectivas.Alzheimer's disease (AD) is present in millions of people around the
world, having a great impact not only on the people who have the disease but
also on their family caregivers, causing them physical and psychological health
problems related to their role. For this reason, it is important to ensure that they
have an adequate quality of life. This systematic review aims to examine the
effectiveness of different intervention programmes aimed at improving the wellbeing of family caregivers of people with AD. The present analysis was based
on 20 studies that met the previously established inclusion criteria and were
selected from the databases "PsycINFO (EBSCO)", "PsycArticles" and
"PubMed". As a result, it has been found that the interventions carried out in the
studies analysed have obtained positive results in improving the quality of life of
caregivers, with cognitive - behavioural interventions being the most effective
Local Governance in Mexico. The Case of Nuevo Leon 2015-2021
The purpose of this paper is to provide some theoretical and empirical elements to measure the level of governance using an empirical case that will focus on the analysis of the 2015-2021 administration of the Government of the State of Nuevo Le n The governance model is evaluated based on the weighting of the degree of effectiveness efficiency and legitimacy that can be observed from the analysis of state public management and the evaluation of some public policies For the development of the project the World Bank s governance index is used as a reference which includes the measurement of six variable
The Importance of Health and Social Protection Assets in the Economic Welfare of Households in Mexico
This paper seeks determines how the possession of health and social protection assets affects the probability of a household belonging to a given quintile of a proposed asset ownership index. An ordered logistic regression model was constructed. As a dependent variable, the quintile of each household was used according to the index. This research is based on 48 explanatory variables from the 2020 National Income and Expenses Survey. It confirms that health and social protection assets are relevant in the location of households in a quintile according to its socioeconomic condition. Estimated marginal effects and predictions for every quintile, show that the effect of the assets varies according to the quintile. Ownership of specific assets increase the likelihood of belonging to the higher quintiles. The possession of a voluntary pension fund is the most relevant asset. The empirical results obtained may contribute to design more efficient inequality-reducing public policies by promoting its acquisition and thereby encouraging social mobility. Main limitations of this research are related with the small number of health and social-protection related variables in the survey.importancia de los activos de salud y protección social en el bienestar económico de los hogares en MéxicoEste artículo busca determina cómo la posesión de activos de salud y protección social afecta la probabilidad de pertenencia de un hogar a un determinado quintil de un índice de activos propuesto. Se construyó un modelo de regresión logística ordenada. Como variable dependiente se usó el quintil de cada hogar según el índice propuesto. Se usaron 48 variables explicativas de la Encuesta Nacional de Ingreso y Gasto de los Hogares 2020. Se confirma que los activos de salud y protección social son relevantes en la ubicación de los hogares en un quintil según su condición socioeconómica. Los efectos marginales estimados y las predicciones para cada quintil muestran que el efecto de los activos varía según el quintil y que determinados activos aumentan la probabilidad de pertenecer a los quintiles más altos. La posesión de un fondo de pensiones voluntario es el activo más relevante. Los resultados empíricos obtenidos pueden contribuir al diseño políticas públicas más eficientes para reducir la desigualdad al promover su adquisición e incentivar la movilidad social. Las principales limitaciones de esta investigación se relacionan con el número reducido de variables de salud y protección social en la encuesta
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