Papers by José R Nuñez-Alvarez
TELKOMNIKA Telecommunication Computing Electronics and Control, 2025
Production processes in modern industry demand higher levels of quality and efficiency in their p... more Production processes in modern industry demand higher levels of quality and efficiency in their products. The "Hermanos Díaz" Oil Refinery Company of Santiago de Cuba, a fundamental pillar in the economic and social development of the eastern part of the country, has a chemical water treatment plant responsible for supplying processed water to the industry's boilers. The current state of this plant supports the lack of optimal physicalchemical conditions in the water it delivers and, therefore, the gradual deterioration of the boilers. This work conceives an automation solution for the dosing, precipitation, and clarification processes of the chemical water treatment plant. Control systems were designed based on instrumentation proposals, enabling reliable measurements and practical actions. In addition, an algorithm of supervision and automatic control using a programmable programmable logic controller (PLC) is presented, making the plant capable of delivering a product in optimal conditions. Images were designed for local and remote process control using a human-machine interface (HMI) panel and a supervisory control and data acquisition (SCADA) system. Finally, an automation architecture with a decentralized periphery is proposed to ensure safety and accuracy in the system's decision-making through communication protocols.
MethodsX, 2025
This research explores implementing renewable energy technologies for power generation using mult... more This research explores implementing renewable energy technologies for power generation using multi-criteria decision-making (MCDM) methods, including AHP, FAHP, TOPSIS, and FUZZY-TOPSIS. Ten renewable energy alternatives were evaluated across seven geographic regions in Colombia, revealing preference variability depending on the method and scenario.
International Journal of Thermofluids, 2024
This study focuses on the experimental investigation of the efficiency of a humidifier-dehumidifi... more This study focuses on the experimental investigation of the efficiency of a humidifier-dehumidifier (HDH) desalination process. The system employs a closed-air cycle, utilizing a hybrid (solar-electric) air heater to increase the air temperature before entering the humidifier. Additionally, a Vapor Absorption Refrigeration (VAR) system is employed to decrease the temperature of the water before it enters the dehumidifier. The system is suitable for deployment in regions with high temperatures and humidity levels. Tests have been conducted under prevailing weather conditions. Temperature and relative humidity at various stages of the cycle are measured and recorded using a dedicated sensor. This study examines the effects of different parameters, including air mass flow rate (MFR) and air temperature at the humidifier inlet, on fresh water production (FWP), coefficient of performance (COP), and gained output ratio (GOR). The results section presents the experimental findings, which show that the maximum COP, GOR, and FWP achieved values of 2.1, 4.1, and 200 g/h, respectively. Furthermore, an increase in air MFR corresponds to an increase in both COP and FWP, while GOR values show a decrease. Based on the eco-analysis conducted for this investigation, the cost per liter (CPL) was calculated to be 0.
Processes, Nov 14, 2022
The number of injector holes and the fuel-injection pressure in an internal combustion engine can... more The number of injector holes and the fuel-injection pressure in an internal combustion engine can affect engine performance and exhaust emissions. Conversion of a port-injection gasoline engine to an HCNG direct-injection engine improves engine performance and exhaust emissions. In addition, increasing the injection pressure helps to increase engine performance. In this study, AVL Fire software was used to perform simulation by certain adjustments. The injection pressure was applied in mods of 15, 20, and 25 bars, the injector holes numbers were 3 and 6, the compression ratio changed from 10:1 to 14:1, and the amount of hydrogen enrichment to natural gas was in mods of 10%, 20%, 30%, and 40%. This paper discusses the items above with regard to power, torque, combustion chamber pressure, fuel conversion efficiency, and exhaust emissions. The result determined that increasing the number of injector holes improves the performance engine and reduces CO emission so that the contour plots confirmed the balanced distribution of temperature and pressure. According to obtained results, maximum engine performance improved from 2.5% to 5% at different speeds and 30% added hydrogen, 25 bar injection pressure, and 6-hole injectors. The amount of CO decreased by approximately 30%, and NOx increased by about 10%.
Heliyon
The dynamic behavior of the hydraulic actuator in a system for regulating the electrode's... more The dynamic behavior of the hydraulic actuator in a system for regulating the electrode's position is crucial for the operation of a Ladle Furnace. This work aims to identify, model, and control the hydraulic actuator in the Ladle Furnace of ACINOX Las Tunas. For identifying the system, input signals of Pseudo-Random Binary type and black box models were used. As a result, three models were obtained, two reflecting the process's asymmetric behavior according to the upward or downward movement. The third model approximates the process dynamic behavior around the operating point and includes the uncertainty caused by the weight variation during the electrode wear. The models obtained, with a fit greater than 85%, allow a better understanding of the study case behavior. In addition, these allowed the evaluation of the electrode's weight variation and tuning of several controllers. The optimal one was a novel non-linear PI controller of guaranteed robustness. In future works, the use of a non-linear function could be evaluated to compensate for the asymmetric behavior of the process.
International Journal of Power Electronics and Drive Systems (IJPEDS)
Three speed-control strategies for DC and AC drives are presented in this study: a proportional i... more Three speed-control strategies for DC and AC drives are presented in this study: a proportional integral derivative (PID) control strategy; an internal model control (IMC); and a state-space control by pole assignment with full state observer (ESSO). The three strategies are applied to a case study, demonstrating the potential of each one. Experimental identification was used to obtain the drive models used for the synthesis of the controllers. The three strategies showed satisfactory results when compared with the requirements imposed on the system, in addition to the good rejection of disturbances. However, the IMC strategy showed itself to be a little softer and with no maximum overshoot, which in some cases and some applications is usually a restriction.
Lubricants
A single effect LiBr–H2O absorption refrigeration system coupled with a solar collector and a sto... more A single effect LiBr–H2O absorption refrigeration system coupled with a solar collector and a storage tank was studied to develop an assessment tool using the built-in App Designer in MATLAB®. The model is developed using balances of mass, energy, and species conservation in the components of the absorption cooling system, taking into account the effect of external streams through temperature and pressure drop. The whole system, coupled with the solar energy harvesting arrangement, is modeled for 24 h of operation with changes on an hourly basis based on ambient temperature, cooling system load demand, and hourly solar irradiation, which is measured and recorded by national weather institutes sources. Test through simulations and validation procedures are carried out with acknowledged scientific articles. These show 2.65% of maximum relative error on the energy analysis with respect to cited authors. The environmental conditions used in the study were evaluated in Barranquilla, Colo...
International Journal on Engineering Applications (IREA)
Currently, in Ecuador, the participation of photovoltaic energy is practically symbolic. In the p... more Currently, in Ecuador, the participation of photovoltaic energy is practically symbolic. In the province of Manabí, generation continues to be carried out through the intensive use of fossil fuel, which is expensive, inefficient, and polluting. This happens in a territory with optimal potential. Hence, the objective of the work is to demonstrate the feasibility of introducing a photovoltaic microgrid through the case study. Due to its simplicity and versatility, a methodology was applied to generalize experiences in other territories with similar geographical and climatic conditions. Field research was applied, and the method corresponds to the descriptive-deductive method, using a Geographic Information System (GIS) as a geographic information manager. The PVsyst 6.8.6 tool was used for the technical design of the installation, and the HOMER software was used for the economic feasibility analysis. The results demonstrate the relevance of introducing the photovoltaic microgrid in the distributed generation mode to increase the quality of service and the system's efficiency, reduce energy costs, promote the preservation of natural resources, and reduce CO2 emissions environment.
Journal of Engineering Science and Technology Review
IOP Conference Series: Materials Science and Engineering, 2021
The current research was carried out to analyze the economic feasibility and contribution to home... more The current research was carried out to analyze the economic feasibility and contribution to homes and buildings automation in the field of environmental protection. The objective that led this study was to explore and investigate the increase in comfort and safety, as well as, the reduction in the electrical energy consumption, so that, it is possible to achieve greater energy efficiency in the No 3 building at the Technical University of Manabí (UTM) in Ecuador. In order to, investigate deeply the economic feasibility; it is relevant to be aware of the electric power and automation equipment cost that will be integrated into the Z-wave protocol. Moreover, the electric bill study contracted by the UTM this was developed initially with the monetary value of the electric power, which was regulated by the Electricity Control Agency. On regards to the environmental analysis, it was shown that the projection uses of the domotic system in the teaching building No. 3, not only reflected s...
International Journal of Energy Economics and Policy, 2020
Journal of Engineering Science and Technology Review, 2021
Journal of Physics: Conference Series, 2021
The applications of multi-agent systems (MAS) are growing increasingly in the industrial field du... more The applications of multi-agent systems (MAS) are growing increasingly in the industrial field due to the advantages inherent to their characteristics and properties, the use of distributed automation architectures, which have satisfactorily solved control problems that its complexity and dynamic behavior have not been properly resolved with other approaches under these conditions, intelligent agents must meet the requirements of current automation systems, such as autonomy, flexibility, reconfiguration, in concurrent and collaborative systems, which traditionally do not have been designed to satisfy these characteristics. In the present work, a distributed architecture is proposed for the design of an intelligent agent in a Human-Machine Interface (HMI) for the supervision of the filtering stage of a water purification plant, characterized by the ability to collaborate with the other agents that make up the entire plant. For the projection and design of the system, the Unified Mode...
Journal of Physics: Conference Series, 2021
The rapid development of Information and Communication Technologies (ICT) and high-capacity hardw... more The rapid development of Information and Communication Technologies (ICT) and high-capacity hardware components make it necessary to achieve a strong integration of automatic systems based on new paradigms on intelligent distributed architectures, where require highly complex supervision and control tasks, due to the generated requirements of the new production systems, the high number of variables to control and the advancement of technologies, especially in industries where continuous processes have been established. In the present work, a distributed hierarchical modular architecture is proposed for a supervision system, based on multi-agent systems (MAS), oriented to the management of processes in the filtration stage of a water purification plant, using a methodology to the implementation of intelligent agents that allow to project, design, verify and validate the system. This methodology is fundamentally based on the use of the Unified Modeling Language (UML) for its projectio...
Journal of Physics: Conference Series, 2021
This article proposes a control of lighting and electrical loads, suitable for smart homes, using... more This article proposes a control of lighting and electrical loads, suitable for smart homes, using embedded systems with low-cost wireless communication modules. The system is based on a distributed intelligent home automation architecture, to work autonomously or interconnect wirelessly to a larger system. It has a set of sensors that allow you to ration the use of electricity through automatic switching off the lights or electrical devices, allowing the lighting to be regulated. It has several modules that communicate to a central node wirelessly, and an interface based on a mobile application. UML and Petri Nets were used for the projection, modelling and validation of the system, its implementation was developed in C/C ++ language for 32-bit microcontrollers. Tests of the prototype showed stable behavior, fast communications and sufficient coverage for a single-family house, whose performance is higher to other similar works found in the scientific community.
Ocean & Coastal Management, 2020
Although public participation (PP) has influenced some integrated coastal zone management (ICZM) ... more Although public participation (PP) has influenced some integrated coastal zone management (ICZM) programs around the world, researchers have rarely analyzed this component specifically inside an ICZM cycle. Furthermore, the approach for integrating environmental energy planning tools within the ICZM Programs for the Small Island Developing States (SIDS) has presented an ongoing challenge for specialists involved in management issues. In Cuba, plans for coastal development are supported by land use planning activities and environmental planning tools. However, the functions and outputs of those tools are "non-obvious", precluding sufficient integration among them. As these aforementioned actions have not been systematically carried out in the Cuban territory, and the systems of inter-institutional relationships with local communities have presented some insufficiencies, the national marine-terrestrial interphase has suffered some negative environmental impacts impossible to be solved by the national authorities. Designing a new methodology that incorporates PP and environmental energy planning tools in the stages of an ICZM program is the objective of this article. The methodology was named MePuPa and has improved current tools for land use planning and ICZM in Cuba. Previously selected "Local Indicators of Environmental Sustainability", applied in two geo-systemic units in the southeastern region of Cuba, were used to demonstrate the methodology. The qualitative and qualitative methods in the proposed MePuPa were also applied. Finally, the MePuPa methodology was tested for four of its five stages. Six advantages and five learned lessons were identified during the Preparation to Proposal stages. MePuPa resulted in a useful local management tool for environmental energy planning, ICZM, economic and agricultural activities, strategic ecosystems recovery, as well as improvements to the governance and decision-making processes in one SIDS.
IEEE Access, 2021
Many studies applying Brain-Computer Interfaces (BCIs) based on Motor Imagery (MI) tasks for reha... more Many studies applying Brain-Computer Interfaces (BCIs) based on Motor Imagery (MI) tasks for rehabilitation have demonstrated the important role of detecting the Event-Related Desynchronization (ERD) to recognize the user's motor intention. Nowadays, the development of MI-based BCI approaches without or with very few calibration stages session-by-session for different days or weeks is still an open and emergent scope. In this work, a new scheme is proposed by applying Convolutional Neural Networks (CNN) for MI classification, using an end-to-end Shallow architecture that contains two convolutional layers for temporal and spatial feature extraction. We hypothesize that a BCI designed for capturing event-related desynchronization/synchronization (ERD/ERS) at the CNN input, with an adequate network design, may enhance the MI classification with fewer calibration stages. The proposed system using the same architecture was tested on three public datasets through multiple experiments, including both subject-specific and non-subject-specific training. Comparable and also superior results with respect to the state-of-the-art were obtained. On subjects whose EEG data were never used in the training process, our scheme also achieved promising results with respect to existing non-subject-specific BCIs, which shows greater progress in facilitating clinical applications.
IOP Conference Series: Materials Science and Engineering, 2020
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Papers by José R Nuñez-Alvarez
La presente guía de laboratorio de máquinas eléctricas rotativas alimentadas con Corriente Alterna (CA) contiene un grupo de prácticas enumeradas y organizadas por orden de complejidad para realizarse durante el semestre académico en el marco de la asignatura de Máquinas Eléctricas II. Adicionalmente, contiene el listado de instrumentos necesarios y tareas experimentales para la realización de la misma, arribando a las conclusiones de la práctica.
Estamos seguro que estas guías facilitarán el proceso de enseñanza y aprendizaje de nuestros estudiantes aportando herramientas que favorezcan la adquisición de conocimientos y habilidades significativas.
mantener informada de forma eficaz a los tomadores de decisiones, y a la población en general, mediante el uso de un sistema de alertas por amenazas meteorológicas extremas. Para su diseño se realizó una investigación sobre los Sistemas de Alertas Tempranas (SAT) e instituciones de vigilancia de estos eventos en Cuba, así como, sobre la estructura del funcionamiento, descripción conceptual y formas de articulación de las tecnologías de la información. Se demostraron además los vínculos existentes entre los SAT y los programas de Manejo Integrado de Zonas Costeras (MIZC).
Como resultado principal del capítulo se desarrolla una herramienta informática web que integra y visualiza múltiples alertas tempranas ante
fenómenos climáticos extremos de corta y prolongada duración, contribuyendo a una adecuada gestión en la reducción del riesgo de desastres.