The reconversion of port spaces in the cities and surroundings of the ports in Panama. Statistical study of traffic and its impact, proposal for improvement

Panama is a country with a privileged geographical and climatic position, which has allowed it to develop as a center/hub of the Americas. The economy is mainly based on the service sector that includes the Panama Canal, and ports and related activities such as the Colon Free Zone, tourism and airport services, and the International Banking Center. As part of Panama's port logistics development, there is a container transfer system from the Pacific to the Atlantic by road or rail. Currently, the road infrastructure does not have perfect conditions, consequently this does not allow it to generate good logistics performance between the final destinations and the different ports that they serve. For this reason, the ports around the Atlantic and Pacific entrances of the Panama Canal have specialized in the movement of containerized cargo and have developed one of the most recognized transshipment centers in Central America. The objective of the study presented in this initial research proposal is to carry out a bibliographic review. Know the literature that has been written about the main effects on the maritime or access zone, the land or maneuvering zone, and the liaison zones with land transport, which are causing a delay in the mobilization of trucks, in the Panamanian Pacific. The methodology of this work was to carry out an exhaustive bibliographical review of the literature on the effects of waiting times, described by the media, magazines of the maritime sector, and especially how the institutions have generated improvement plans for a development to long-term needs of the sector maritime. The results obtained are the contributions of all those involved in the maritime sector, both the private sector and the state, who seek to improve the process that is currently being developed in the Pacific ports. In conclusion, a series of recommendations of the contributions of the private sector and state institutions are proposed, such as the strengthening of the legal framework, improving the management, exploitation, and promotion of infrastructure, are the goal in which the two sectors agree. Who are analyzing the problems suffered by the infrastructure of the Pacific ports.Postprint (author's final draft

Análisis del cumplimiento de los objetivos de energía y clima para el año 2030 en la Unión Europea. Caso de estudio: el estado español

La Unión Europea, movida por el creciente interés de la sociedad por la sostenibilidad en la actividad del ser humano, pretende abordar el problema del cambio climático y la contaminación en el futuro estableciendo objetivos para mejorar diferentes problemáticas climáticas y energéticas: la reducción de emisiones de gases de efecto invernadero producidas por la actividad de los seres humanos, el uso de fuentes de energía renovables y la mejora de la eficiencia energética y el ahorro de energía. Este trabajo pretende realizar una diagnosis del estado de cumplimiento de los principales objetivos de la Unión Europea para 2030 en un caso de estudio: el Estado español. Para ello revisar la situación de las tres problemáticas principales tratadas por esos objetivos en diferentes niveles de enfoque: un enfoque mundial y un enfoque de la Unión Europea en su conjunto. De esta manera, conocer el estado del arte de las problemáticas a estudiar y utilizar esa información para la diagnosis centrada en el Estado español, con la que lograr exponer la realidad del caso de estudio ante los objetivos de 2030, en la actualidad y en el futuro, y realizar propuestas de mejora, en caso de ser necesarias, para mejorar la perspectiva de futuro del cumplimiento de los objetivos en 203

Spatial structure and velocity fluctuations in turbulent bubble jets in microgravity

We study the dynamics of turbulent jets of bubbles created by the injection of a slug flow into a quiescent cavity, both theoretically and experimentally using data from drop tower experiments. The generated bubble jets exhibit a remarkably low degree of coalescence leading to virtually monodisperse suspensions of spherical bubbles. The turbulence of the jet is responsible for the spatial spreading of the bubble distribution in roughly conical jets. We propose a stochastic model for the dispersion of bubbles in the jet, in which the trajectories of individual bubbles can be computed from the stationary solution of a k-epsilon model. Bubble concentration behaves to a good approximation as a passive scalar with a non-homogeneous diffusion. Numerical integration of the model compares well with the experimental data.Peer ReviewedPostprint (published version

Monodisperse bubble suspensions in turbulent flows in microgravity. Drop Tower experiments

Peer ReviewedPostprint (published version

Bubble dynamics in turbulent duct flows: Lattice-Boltzmann simulations and drop tower experiments

Lattice-Boltzmann simulations of a turbulent duct flow have been carried out to obtain trajectories of passive tracers in the conditions of a series of microgravity experiments of turbulent bubble suspensions. The statistics of these passive tracers are compared to the corresponding measurements for single-bubble and bubble-pair statistics obtained from particle tracking techniques after the high-speed camera recordings from drop-towers experiments. In the conditions of the present experiments, comparisons indicate that experimental results on bubble velocity fluctuations are not consistent with simulations of passive tracers, which points in the direction of an active role of bubbles. The present analysis illustrates the utility of a recently introduced experimental setup to generate controlled turbulent bubble suspensions in microgravity.Peer ReviewedPostprint (author's final draft

Generation and control of monodisperse bubble suspensions in microgravity

A new experimental setup for the generation of homogeneous, monodisperse bubble suspensions in turbulent duct flows in microgravity has been designed and tested in drop tower experiments. The setup provides independent control of bubble size, void fraction and degree of turbulence. The device combines several slug-flow injectors that produce monodisperse bubble jets, with a turbulent co-flow that ensures homogeneous spatial spreading. Bubble separation in the scale of the most energetic eddies of the flow, and bubble size sufficiently smaller, ensure that turbulence is most efficient as a mechanism for spatial spreading of bubbles while preventing coalescence, thus optimizing the homogeneous and monodisperse character of the suspension. The setup works in a regime for which bubbles are spherical, but sufficiently large compared to the turbulent dissipative scales to allow for two-way coupling between bubbles and carrying flow. The volume fraction is kept relatively small to facilitate particle tracking techniques. To illustrate the potential uses of the method we characterize the statistics of bubble velocity fluctuations in steady regimes and we characterize the transient relaxation of the buoyancy-driven pseudo-turbulence when gravity is switched-off.We acknowledge the support from ESA for the funding of the drop tower experiments that provided the raw data analyzed and the ZARM crew, in particular to Dieter Bischoff, for their valuable support all along the experiments and their hospitality. We acknowledges financial support from Ministerio de Economia y Competividad (Spain) under projects FIS2013-41144-P, FIS2016-78507-C2-2-P (J.C.), FIS2015-66503-C3-2-P (L.R.-P., also financed by FEDER, European Union), ESP2014-53603-P (X.R.), and Generalitat de Catalunya under projects 2014-SGR-878 (J.C.), 2014-SGR-365 (X.R.). P.B. acknowledges Ministerio de Ciencia y Tecnología (Spain) for a pre-doctoral fellowshipPreprin

Microbubble injector: an experimental quantitative characterization

Peer Reviewe

Characterization of the performance of an injector for the controlled generation of microbubbles

We perform a characterization of a recently reported microbubble injector in conditions relevant to microgravity. Injection of bubbles is based on the generation of a slug flow in a capillary T-junction, whose operation is robust to changes in the gravity level. We address questions regarding the performance under different working regimes. In particular, we focus on the regimes found within a large range of gas and liquid injection flow rates. The injection performance is characterized by measuring bubble generation frequency. We propose curves obtained empirically for the behavior of generation frequency and crossover between regimes.Peer Reviewe

Characterization of the performance of an injector for the generation of controlled microbubbles

Peer Reviewe

Experimental characterization of a microbubble injector

Peer Reviewe