Dpto. Ingeniería Mecánica, Energética y de Materiales - Mekanika, Energetika eta Materialen Ingeniaritza Saila

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Compound Petri nets and alternatives aggregation Petri nets: two formalisms for decision-making support
(SAGE, 2016) Latorre Biel, Juan Ignacio; Jiménez Macías, Emilio; Pérez de la Parte, Mercedes; Sáenz Díez, Juan Carlos; Martínez Cámara, Eduardo; Blanco Fernández, Julio; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
Decision-making in technological systems, such as communication networks, manufacturing facilities and supply chains, constitutes a common requirement able to lead companies galore to success or failure. This article presents a decisionmaking methodology, where the feasible structural configurations to be analysed are chosen heuristically in the frame of a single optimization problem. For stating the optimization problem and solving it efficiently, appropriate formalisms would be used. Compound Petri nets, a particular kind of parametric Petri nets, and alternatives aggregation Petri nets, are two Petri net–based formalisms able to integrate in the same model different alternative structural configurations. Moreover, even having different characteristics that might make them useful for different applications, both formalisms present common features, such as including a set of exclusive entities and the possibility of developing compact Petri net models, by the removal of redundant information. This article is also focused on the transformation algorithm between compound Petri nets and alternatives aggregation Petri nets. This algorithm is devoted to transform a model described by one of the formalisms into an equivalent model, that is, with the same behaviour, represented using the other formalism. Finally, several application examples are given for illustrating the steps of the transformation algorithm.
Open Access
Control of discrete event systems by means of discrete optimization and disjunctive colored PNs: application to manufacturing facilities
(Hindawi, 2014) Latorre Biel, Juan Ignacio; Jiménez Macías, Emilio; Pérez de la Parte, Mercedes; Blanco Fernández, Julio; Martínez Cámara, Eduardo; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
Artificial intelligence methodologies, as the core of discrete control and decision support systems, have been extensively applied in the industrial production sector. The resulting tools produce excellent results in certain cases; however, the NP-hard nature of many discrete control or decision making problems in the manufacturing area may require unaffordable computational resources, constrained by the limited available time required to obtain a solution. With the purpose of improving the efficiency of a control methodology for discrete systems, based on a simulation-based optimization and the Petri net (PN) model of the real discrete event dynamic system (DEDS), this paper presents a strategy, where a transformation applied to the model allows removing the redundant information to obtain a smaller model containing the same useful information. As a result, faster discrete optimizations can be implemented.This methodology is based on the use of a formalism belonging to the paradigmof thePNfor describingDEDS, the disjunctive colored PN. Furthermore, the metaheuristic of genetic algorithms is applied to the search of the best solutions in the solution space. As an illustration of the methodology proposal, its performance is compared with the classic approach on a case study, obtaining faster the optimal solution.
Open Access
Environmental impact analysis of natural cork stopper manufacturing
(MDPI, 2022) Flor Montalvo, Francisco Javier; Martínez Cámara, Eduardo; García Alcaraz, Jorge Luis; Jiménez Macías, Emilio; Latorre Biel, Juan Ignacio; Blanco Fernández, Julio; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
For both wine makers and customers, natural cork stoppers are a symbol of quality. More-over, they are essential for maintaining the organoleptic properties of bottled wines throughout their lifespan. This research relied on the life-cycle assessment (LCA) methodology to analyze the relationship between the efficient usage of cork planks and the environmental impact of the cork stopper manufacturing industry. The goals of this research were to analyze and determine the environmental impact of producing 1 kg of natural cork stoppers. The analysis considered cork stoppers of two sizes—24 × 44 mm and 26 × 44 mm—and two manufacturing methods—punching and turning. Our findings indicated that the 24 × 44 mm cork stoppers produced with the punching method had a slightly lower environmental impact (1.36 kg CO2 eq/kg) across the ten analyzed impact categories. Conversely, 26 × 44 mm turned corks had the highest impact on the environment (1.49 kg CO2 eq/kg). Additionally, a comparison of same-sized punched and turned cork stoppers showed that the former had a lower environmental impact. This phenomenon is directly related to plank usage. In conclusion, there is a clear relationship between environmental impact and the efficient usage of raw material. In turn, an efficient usage of raw material depends on both the manufacturing method and stopper size.
Open Access
Methodology for energy demand reduction of potato cold storage process
(Wiley, 2022) Sáenz Baños, Mercedes Irache; Latorre Biel, Juan Ignacio; Martínez Cámara, Eduardo; Jiménez Macías, Emilio; Longo, Francesco; Blanco Fernández, Julio; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
In order to maintain the quality of the potatoes over time, it is necessary to store them under certain storage conditions, which minimize losses both of quality and product, preferably without using chemical treatments. Conservation chambers consume a considerable amount of energy. Between 60% and 70% of the electricity consumed is used in refrigeration. Good insulation reduces the need for cooling the potato since its optimum storage temperature for consumption is around 4–7 C and relative humidity is 85%–90%. This research studies potatoes’ cold storage process to minimize the cost in the product value chain and to ensure its competitiveness in the market. A model is developed to assess energy consumption and propose measures to reduce energy, environmental, and economic costs. All this to reduce their impact within the value chain of potato consumption. Practical Applications: In this case study, different energy efficiency measures applied to the cold storage of potatoes have been implemented: replacement or improvement of the performance of refrigeration equipment, insulation and infiltrations in the refrigeration chamber, control of the product entry temperature, thermal conditioning through free-cooling, improvements in lighting equipment, technical management, and supervision of facilities, and thermographic control. The set of actions implemented has allowed to obtain a reduction in energy demand, standardized through the developed reference line, by 16.41% compared to previous years.

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