Power Optimization of Multi-fluid Transportation Systems

6th IFAC/IFIP/IFORS/ IMACS Symposium on Information Control Problems in Manufacturing Technology, 26/09/1989. madrid.This paper presents an algorithm for optimizing the energy operating costs in multi-fluid transportation systems. The algorithm works in two steps. The first one consists of the computation of a function that measures the estimated minimum cost to the goal node. This computation involves the use of Bellman’s optimality principle and some heuristic rules in order to avoid the combinatorial explosion. During the second step the optimum trajectory is obtained with the help of the function mentioned above and using an accurate simulation of the transportation system. The algorithm is applied to a model of an oil pipeline system

Optimal Operation of Pipeline Transportation Systems

11th Triennial World Congress. Tallinn. Estonia. USSR. 1990This paper presents a simulator of an oil pipeline for scheduling purposes. The simulator includes an algorithm for optimizing the energy operating costs. The optimization algorithm works in two steps. The first one consists of the computation of a function that measures the estimated mininltun cost to the goal node. This computation involves the use of Bellman's optimality principle and of some heuristic rules in order to avoid the combinatorial explosion. During the second step the optinltmum trajectory is obtained with the help of the function mentioned above and using an accurate simulation of the transportation system. The simulation considers those aspects which are relevant t.o the optimization problem and takes into account the following factors: topology and topography of the network. non-linear characteristics of pumps and pipelines, variable demands of consumers, time changing prices of electrical energy and hydraulic equations throughout the system. The simulator is being used by CAMPSA (the major oil distribution company in Spain) Some results obtained with an oil pipeline system in Northern Spain are presented in the paper

Crystallisation of amorphous Al-Y-Ni-(Cu)alloys

The nanocrystallisation behaviour and subsequent intermetallics formation of an amorphous Al88-Y4-Ni8 alloy has been studied. A 1 at% of Al or Ni was also substituted by Cu and its effect studied. Differential scanning calorimetry has been used to measure the thermal stability of these amorphous alloys. Transmission electron microscopy showed the smaller size of the nanocrystals obtained during primary crystallisation when Cu is added. Using three-dimensional atom probe, it has been checked that Cu is homogeneously distributed in the amorphous matrix, not contributing to a heterogeneous nucleation around Cu clusters during the formation of nanocrystals. Transmission electron microscopy and X-rays diffraction are used to study the controversial intermetallics occurrence at higher temperatures. The sequence and characteristics of the intermetallics appearing in these alloys were sensitive to the presence of Cu. The evolution of these intermetallics, up to 600 ºC, has been studied. Findings are compared with previous studies.Ministerio de Economía y Competitividad DPI2015-69550-C2-2-

Synthesis and characterization of in situ-reinforced Al–AlN composites produced by mechanical alloying

This research is focused on the production of aluminum matrix composites (AMCs) reinforced with various percentages of aluminum nitride (AlN). For this purpose, aluminum powder was milled at room temperature for a total time of 5 hours. The percentage of reinforcement is varied by milling under different periods of vacuum followed by ammonia gas flow. X-ray diffraction analysis showed the benefits of using a combined milling atmosphere to form, after the heat treatment of the powder, a higher amount of AlN. Results showed that the period in vacuum determines the greater or lesser capacity to absorb nitrogen during the ammonia gas period. Even using shorter vacuum milling periods, the AlN formed after sintering can be increased.Ministerio de Economía, Comercio y Empresa DPI2015-69550-C2-1-

Consolidation by MF-ERS of mechanically alloyed Al powder

The aim of this work is to study the viability of producing, by medium-frequency electrical resistance sintering (MF-ERS), compacts from mechanically alloyed aluminium powders. The MF-ERS process was carried out using different values of current intensity (6, 8, 10 and 11 kA) and dwelling (heating) times (400, 700 and 1000 ms). Results were compared with compacts processed by the conventional cold pressing and sintering route (850 MPa and 650 C-1h). Depending on the processing route different properties were obtained. The final porosity of the MF-ERS compacts (23.6e7%) can be as low, under the tougher tested sintering conditions, as that of the conventionally produced compacts (6%). The compacts obtained by MF-ERS are less ductile, with lower compression strength than that obtained by the conventional route. Furthermore, a similar electrical resistance and higher microhardness can be reached by the MF-ERS process, despite the duration of the consolidation process is only a fraction of that of the conventional process.Ministerio de Economía y Competitividad DPI2015-69550-C2-1-PFondo Europeo de Desarrollo Regional (FEDER) DPI2015-69550-C2-2-

Modelling and Simulation of the Electrical Resistance Sintering Process of Iron Powders

In this paper, the process known as Electrical Resistance Sintering under Pressure is modelled, simulated and validated. This consolidation technique consists of applying a high-intensity electrical current to a metallic powder mass under compression. The Joule efect acts heating and softening the powders at the time that pressure deforms and makes the powder mass to densify. The proposed model is numerically solved by the fnite elements method, taking into account the electrical–thermal–mechanical coupling present in the process. The theoretical predictions are validated with data recorded by sensors installed in the electrical resistance sintering equipment during experiments with iron powders. The reasonable agreement between the theoretical and experimental curves regarding the overall porosity and electrical resistance suggests that the model reproduces the main characteristics of the process. Also, metallographic studies on porosity distribution confrm the model theoretical predictions. Once confrmed the model and simulator efciency, the evolution of the temperature and the porosity felds in the powder mass and in the rest of elements of the system can be predicted. The infuences of the processing parameters (intensity, time and pressure) as well as the die material are also analyzed and discussed.Fondo Europeo de Desarrollo Regional (FEDER) DPI2015- 69550-C2-1-PMinisterio de Educación y Ciencia DPI2015-69550-C2-2-

Entorno de soporte para el autoaprendizaje en el diseño de circuitos digitales

El diseño de circuitos digitales forma parte de las competencias básicas de los nuevos Grados en Ingeniería Informática e Ingeniería de Telecomunicaciones. Un obstáculo importante para el aprendizaje de dichas competencias es que las herramientas académicas existentes para el diseño de circuitos no permiten validar si un diseño se ajusta a la especificación de partida. En este artículo, se describe un entorno de autoaprendizaje para que los estudiantes puedan realizar ejercicios de diseño de circuitos y recibir un feedback continuo