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

Estrategias de Negocios

Los grandes cambios en las esferas del conocimiento, han llevado a todos los sectores a desarrollar estrategias, mecanismos y políticas encaminadas a satisfacer la demanda de productos y servicios de la población. En este ejercicio, las proyecciones empiezan a fallar, desde que se considera como objetivos únicos el incremento de la producción sin considerar las variables del entorno. Es necesario entonces desarrollar mecanismos que permitan conducir el desarrollo y la producción en un marco de eficiencia y sustentabilidad y no solo de productividad. En la observancia de este proceso, las estrategias implementadas en cualquier etapa del desarrollo deben obedecer tanto a los lineamientos y a las políticas establecidas, pero sobre todo equilibrar dichas políticas con procedimientos y metodologías que identifiquen, solucionen y desarrollen la empresa o prestadora de servicios que se trate. Es entonces que el conocimiento general y particular del entorno y su análisis, permitirán el establecimiento y ejecución de estrategias para lograr la dualidad de producción y servicio con eficiencia y sustentabilidad. Las estrategias desarrolladas deben de analizar y ajustarse al entorno en el que los profesionistas se desarrollaran en un futuro, en el área agroindustrial. Dentro de las políticas públicas actuales el fomento a la cultura emprendedora marca uno de los ejes de desarrollo de microempresarios para lo que el conocimiento de estrategias de desarrollo empresarial se convierte en necesidad

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

Current status of research in Colombia organizational and work psychology

A partir de una conceptualización de la psicología de las organizaciones y del trabajo (POT) se describen los temas y problemas del campo a nivel global y el rol de la investigación. Posteriormente se presenta el estado actual de la investigación en POT en Colombia, sus límites y posibilidades futuras. Con base en lo reportado por el sistema de información de COLCIENCIAS, se analizan las características y aspectos comunes de los ocho grupos de investigación en POT, de los cuales dos están categorizados, tres reconocidos y tres registrados. A continuación, se presentan la agenda y reflexiones de los tres encuentros de la Red de Investigadores en POT en Colombia. Se concluye que son grandes los avances, en especial en los dos últimos años. A la vez, preocupan el bajo número de investigadores con nivel de maestría y doctorado en POT y la pobre relación entre los grupos de investigación y las organizaciones-empresas para realizar proyectos de investigación de interés nacional.From the organizational and work psychology (OWP) concept, a description of topics and problems of the field at the global level and the role of research is done. Next, the current state of OWP research in Colombia is presented and its limits and future possibilities. Based on COLCIENCIAS information system, characteristics and communalities of the eight OWP reported groups are analyzed. At this moment there are two categorized groups, three recognized groups and three registered groups. Then, agenda and reflections of the three meetings of the OWP Colombian Researchers Net are presented. It is concluded that there are important achievements, especially in the last two years. At the same time, there is concern about the low number of researchers with PhD and Master Degrees and the poor relation between research groups and organizations to run research projects of national interest

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

Humility : Virgin or Virtue?

This paper considers Marian iconography in which the Virgin is depicted sitting on the ground, known as the Virgin of Humility. The creation of this Marian type coincides with Saint Thomas's systematization of the virtues, which resulted in a decline in the importance of the virtue of Humility. The combination of both cultural traditions has led to a correspondence between the virtue of Humility and the images of the Virgin of Humility. The genesis of this latter type is based on the textual sources and part of the visual representation of Humility, which was replaced during the 14th and 15th centuries

A proposal for an air quality monitoring system for Cartagena de Indias

This paper presents an Air Quality Monitoring System for the city of Cartagena de Indias. The goal of this system is to monitor the air quality in the city and to establish the current state of the air Cartagena's citizen breathe. Data is going to be acquired through a sensor network, and the information is going to be displayed on web or mobile application allowing access from anywhere in the world to anyone that may be interested. It is expected that the availability of this information allows research centers, educational institutions, and government to design plans for prevention and improvement of the air quality in the city based on historical and real-time data. © 2019 Latin American and Caribbean Consortium of Engineering Institutions. All rights reserved

Evaluación de las actividades antibacteriana y antisap de extractos de la parte aérea de Palicourea guianensis (Rubiaceae)

En el presente trabajo se llevó a cabo la evaluación de las actividades antibacteriana y antiSAP (Proteinasa Aspártica Secretada) de Candida albicans de los extractos crudos de n-hexano, diclorometano, acetato de etilo y agua de la parte aérea de Palicourea guianensis; adicionalmente, se realizó un perfil fitoquímico por medio de espectrofotometría ultravioleta (UV) y pruebas características de determinados metabolitos secundarios. La determinación de la actividad antibacteriana se realizó por medio de la técnica de difusión en agar, frente a los microorganismos Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa y Bacillus cereus; los extractos no mostraron resultados positivos a las concentraciones evaluadas. La evaluación de la actividad antiSAP, se determinó mediante cuatro técnicas diferentes: Espectrofluorometría, HPLC, electroforesis SDS-PAGE y RT-PCR en tiempo real, mostrando porcentajes de inhibición del 50% con relación al control positivo, pepstatina A; siendo los más promisorios el extracto en diclorometano y el acuoso. También se estudió de la cinética de inhibición tanto enzimática como a nivel de expresión de genes usando las técnicas de fluorometría y RT-PCR en tiempo real, respectivamente.In the present study was conducted evaluating the antibacterial activities and antiSAP (Secreted aspartic proteinases) of Candida albicans extracts of n-hexane, dichloromethane, ethyl acetate and water from the aerial part of Palicourea guianensis, in addition, was performed a phytochemical profile by ultraviolet spectrophotometry (UV) and evidence of certain secondary metabolites features. Determination of antibacterial activity was performed by the agar diffusion method, against microorganisms Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus, the extracts showed no positive results at concentrations tested. The assessment of antiSAP activity was determined by four different techniques: spectrofluorimetry, HPLC, SDS-PAGE and RT-PCR in real time, showing inhibition percentages of 50% compared to positive control, pepstatin A; the most promising being the dichloromethane extract and the aqueous extract. We also studied the kinetics of inhibition of both, enzymatic and genetic expression level using fluorometry techniques and RT-PCR in real time, respectively. The most promising extracts against antiSAP activity were the dichloromethane extract and the aqueous respectively

Implementación de un OVA sobre educación sexual como estrategia educativa en la Institución Ciudadela Cuba

En vista de las crecientes demandas y necesidades del uso de las herramientas tecnológicas en la vida cotidiana y de la incidencia que estas tienen en la vida de los estudiantes de básica secundaria, se considera pertinente captar la atención y el interés de los jóvenes vinculando Objetos Virtuales de Aprendizaje con educación en métodos anticonceptivos. Teniendo en cuenta que el 54 % de los estudiantes de grado séptimo de la Institución Educativa Ciudadela Cuba abordan el tema de métodos anticonceptivos en el aula, es de suma importancia realizar un OVA donde los estudiantes cuenten con la información necesaria para que hagan uso pertinente de estos. Este proyecto educativo pretende dar a conocer información pertinente y clara sobre métodos anticonceptivos y educación sexual, haciendo uso de un OVA (Objeto Virtual de Aprendizaje). Además, busca generar interés sobre estas nuevas herramientas tecnológicas en relación con la asignatura de educación sexual