Departamento de Bioingeniería e Ingeniería Aeroespacial
http://hdl.handle.net/10016/9269
2015-12-01T21:57:44ZNumerical simulation of heat transfer in a pipe with non-homogeneous thermal boundary condition
http://hdl.handle.net/10016/22012
Numerical simulation of heat transfer in a pipe with non-homogeneous thermal boundary condition
Antoranz Perales, Antonio; Gonzalo Grande, Alejandro; Flores Arias, Óscar; García-Villalba Navaridas, Manuel
Direct numerical simulations of heat transfer in a fully-developed turbulent pipe flow with circumferentially-varying thermal boundary conditions are reported. Three cases have been considered for friction Reynolds number in the range 180–360 and Prandtl number in the range 0.7–4. The temperature statistics under these heating conditions are characterized. Eddy diffusivities and turbulent Prandtl numbers for radial and circumferential directions are evaluated and compared to the values predicted by
simple models. It is found that the usual assumptions made in these models provide reasonable predictions far from the wall and that corrections to the models are needed near the wall.
2015-10-01T00:00:00ZPotentiation of acute morphine-induced analgesia measured by a thermal test in bone cancer-bearing mice
http://hdl.handle.net/10016/21661
Potentiation of acute morphine-induced analgesia measured by a thermal test in bone cancer-bearing mice
González Rodríguez, Sara; González Llamez, Sara; Hidalgo, Agustín; Baamonde, Ana; Menéndez, Luis
Agonists of mu-opioid receptors are currently used in the management of cancer pain. However, several data suggest that the analgesic effect of morphine can diminish during the development of experimental tumors. By using a thermal test, we have studied whether the analgesic effect evoked by morphine is altered in mice bearing two painful bone tumors. The analgesic effect evoked by systemic morphine remained unaltered after the intratibial inoculation of B16-F10 melanoma cells and was potentiated after the inoculation of NCTC 2472 osteosarcoma cells. Although the number of spinal mu-opioid receptors measured by western blot studies was not augmented in osteosarcoma-bearing mice, the analgesia evoked by intrathecal (i.t.) morphine was also enhanced. The analgesic response produced by the spinal administration of the Gi/o protein activator mastoparan was amplified, whereas the analgesic response evoked by the i.t. administration of the N-type calcium channel blocker ?-conotoxin remained unaltered. The efficacy of the GIRK channel blocker tertiapin-Q to antagonize the analgesic effect produced by a maximal dose of morphine was also increased in osteosarcoma-bearing mice. Our results seem to indicate that the analgesic effect of morphine on thermal nociception can be enhanced in response to the development of particular bone tumors in mice, being this potentiation probably related to a greater efficacy of the transduction system driven by Gi/o proteins and GIRK channels.
2012-06-01T00:00:00ZEn-Route Optimal Flight Planning Constrained to Pass Through Waypoints using MINLP
http://hdl.handle.net/10016/21594
En-Route Optimal Flight Planning Constrained to Pass Through Waypoints using MINLP
Soler, Manuel; Olivares, Alberto; Bonami, Pierre; Staffetti, Ernesto
Abstract: In this paper we study the en-route strategic flight planning of a commercial aircraft constrained to pass through a set of waypoints whose sequence is not predefined. This problem has been solved as an hybrid optimal control problem in which, given the dynamic model of the aircraft, the initial and final states, the path constraints constituting the envelope of flight, and a set of waypoints in the European air space, one has to find the control inputs, the switching times, the optimal sequence of waypoints and the corresponding trajectory of the aircraft that minimize the direct operating cost during the flight. The complete layout of waypoints in the European airspace is reduced and waypoints are gathered into a small number of clusters. The aircraft is constrained to pass through one waypoint inside every cluster of waypoints. The presence of multi point constraints makes the optimal control problem particularly difficult to solve. The hybrid optimal control problem is converted into a mixed integer non linear programming problem first making the unknown switching times part of the state, then introducing binary variable to enforce the constraint of passing through one waypoint inside every cluster, and finally applying a direct collocation method. The resulting mixed integer non linear programming problem has been solved using a branch and bound algorithm. The cases studied and the numerical results show the effectiveness, efficiency and applicability of this method for enroute strategic flight plans definition.
2011-06-14T00:00:00ZA Numerical Framework and Benchmark Case study for Muti-modal Fuel Efficient Aircraft Conflict Avoidance
http://hdl.handle.net/10016/21592
A Numerical Framework and Benchmark Case study for Muti-modal Fuel Efficient Aircraft Conflict Avoidance
Soler, Manuel; Kamgarpour, Maryam; Lygeros, John
Abstract: We formulate fuel optimal conflict free aircraft trajectory planning as a hybrid optimal control problem. The discrete modes of the hybrid system capture the air traffic procedures for conflict resolution, e. g., speed and turn advisories. In order to solve problems of realistic dimension arising from air traffic sector planning, we formulate a numerically tractable approach to solve the hybrid optimal control problem. The approach is based on introducing binary functions for each mode, relaxing the binary functions and including a penalty term on relaxation. The transformed and discretized problem is a nonlinear program. We use the approach on a benchmark case study for resolving conflict while minimizing fuel consumption of 8 Airbus 320 aircraft in a symmetrical set up.
2014-05-26T00:00:00Z