On equilibrium existence in infinite horizon economies

In sequential economies with finite or infinite-lived real assets in positive net supply, we introduce constraints on the amount of borrowing in terms of the market value of physical endowments. We show that, when utility functions are either unbounded and separable in states of nature or separable in commodities, these borrowing constraints not only preclude Ponzi schemes but also induce endogenous Radner bounds on short-sales. Therefore, we obtain existence of equilibrium. Moreover, equilibrium also exists when both assets are numerarie and utility functions are quasilinear in the commodity used as numerarie.Equilibrium, Infinite horizon incomplete markets, Infinite-lived real assets.

Infinite horizon economies with borrowing constraints

We consider infinite horizon economies with incomplete financial markets. Securities are in positive net supply and may be infinite-lived. We establish existence of equilibria by requiring borrowing constrains instead of portfolio restrictions..Equilibrium, Infinite horizon incomplete markets, Infinite-lived real assets.

Passenger Exposure to Magnetic Fields due to the Batteries of an Electric Vehicle

In electric vehicles, passengers sit very close to an electric system of significant power. The high currents achieved in these vehicles mean that the passengers could be exposed to significant magnetic fields. One of the electric devices present in the power train are the batteries. In this paper, a methodology to evaluate the magnetic field created by these batteries is presented. First, the magnetic field generated by a single battery is analyzed using finite elements simulations. Results are compared to laboratory measurements, taken from a real battery, in order to validate the model. After this, the magnetic field created by a complete battery pack is estimated and results are discussed

“Diseño de un sistema de gestión por procesos en el departamento de recursos humanos para el manejo integral de los criterios de las certificaciones FLO y FLOR Ecuador en el área”

El presente proyecto se desarrolló en la empresa PONTE TRESA S.A. y en él se encuentran desarrollados temas de la Teoría de Procesos y Comportamiento Organizacional. Se realizó una investigación diagnóstica en donde se evidenció que la empresa PONTE TRESA S.A. aplicaba una gran cantidad de certificaciones de las que algunas, como FLO y FLOR ECUADOR, eran similares. La gestión independiente de éstas, hacían que los responsables realicen funciones repetitivas. Es por esto que se propuso integrar el manejo de las certificaciones comunes en un Sistema de Gestión. La investigación documental, en donde se visualizó la realidad institucional, llegó entre otras a las siguientes conclusiones: La empresa contaba con un organigrama desactualizado. La empresa no contaba con un mapeo de procesos a pesar de que algunos criterios de las certificaciones solicitaban a la organización trabajar bajo esta filosofía. La empresa estaba manejando independientemente el cumplimiento de los criterios de las certificaciones a pesar de que dos de alguna de ellas eran similares. Es en este momento dónde el proyecto se materializa ya que la propuesta se vuelve clara: brindar a la empresa PONTE TRESA S.A. de un Sistema de Gestión por Procesos, para el Departamento de Recursos Humanos, con el fin de conjugar el manejo de los criterios de la Certificaciones FLO y FLOR ECUADOR en lo que se relaciona a los subsistemas de Talento Humano. El reto comienza con el levantamiento, actualización de información obsoleta y elaboración de propuestas para que las personas encargadas puedan analizarlas y aprobarlas, por ejemplo, se planteó un nuevo esquema de Organigrama Funcional el mismo que al ser contrastado con la práctica se evidenció ser el real, quedando así definida una estructura, facilitando la comprensión de la organización. Esta propuesta fue validada y aprobada. Posteriormente, el autor necesitó realizar una amplia investigación respecto a la filosofía de la gestión por procesos y entre varios autores definir que conceptos y prácticas eran los adecuados para su aplicación en el proyecto definiendo así un fuerte sustento teórico que soporta el resultado obtenido. Se destaca la Teoría de Procesos, el manejo del cambio, los conceptos y criterios de las certificaciones FLO Y FLOR ECUADOR, un Estudio Situacional en el que se visualizó los factores internos y externos que influyen sobre la Empresa, un análisis FODA general de PONTE TRESA S.A. y la ejecución de la propuesta en donde a más de establecer el manual de proceso se incluyó un Plan de Gestión del Cambio para reducir la resistencia. En los resultados obtenidos, que se pueden verificar en los ANEXOS, se encuentra un producto de calidad, realizado por un proyectista cuya motivación se basa en su vocación de servicio organizacional, interés por la gestión de procesos y la obtención de su título de Psicólogo Organizacional

Passenger Exposure to Magnetic Fields in Electric Vehicles

In electric vehicles, passengers sit very close to an electric system of significant power, usually for a considerable amount of time. The relatively high currents achieved in these systems and the short distances between the power devices and the passengers mean that the latter could be exposed to relevant magnetic fields. This implies that it becomes necessary to evaluate the electromagnetic environment in the interior of these vehicles before releasing them in the market. Moreover, the hazards of magnetic field exposure must be taken into account when designing electric vehicles and their components. For this purpose, estimation tools based on finite element simulations can prove to be very useful. With appropriate design guidelines, it might be possible to make electric vehicles safe from the electromagnetic radiation point of view

Energy Storage Systems for Electric Vehicles: Performance Comparison based on a Simple Equivalent Circuit and Experimental Tests

The decision to select the most suitable type of energy storage system for an electric vehicle is always difficult, since many conditionings must be taken into account. Sometimes, this study can be made by means of complex mathematical models which represent the behavior of a battery, ultracapacitor or some other devices. However, these models are usually too dependent on parameters that are not easily available, which usually results in nonrealistic results. Besides, the more accurate the model, the more specific it needs to be, which becomes an issue when comparing systems of different nature. This paper proposes a practical methodology to compare different energy storage technologies. This is done by means of a linear approach of an equivalent circuit based on laboratory tests. Via these tests, the internal resistance and the self-discharge rate are evaluated, making it possible to compare different energy storage systems regardless their technology. Rather simple testing equipment is sufficient to give a comparative idea of the differences between each system, concerning issues such as efficiency, heating and self-discharge, when operating under a certain scenario. The proposed methodology is applied to four energy storage systems of different nature for the sake of illustration

Switched Reluctance Drives with Degraded Mode for Electric Vehicles

There are many types of electrical machines suitable for electric vehicles. Nowadays, most manufacturers and researchers tend towards two major alternatives: permanent magnet synchronous machines and induction machines. However, these are not the only competitive candidates. Reluctance machines, which have been well-known for some decades already, present some interesting advantages. For instance, switched reluctance machines are intrinsically redundant and fault-tolerant, which makes them attractive for applications in which robustness is compulsory. In this sense, switched reluctance drives can keep working even when one of their phases loses its functionality for any reason. In an electric vehicle, this would mean being able to keep driving the vehicle even after some failures, although with reduced performance (in degraded mode). In this chapter, switched reluctance drives for traction applications are analyzed, focusing on their capability to operate in degraded mode (with m-1 phases available)

Design Parameter Analysis of Point Absorber WEC via an Evolutionary-Algorithm-Based Dimensioning Tool

Wave energy conversion has an essential difference from other renewable energies since the dependence between the devices design and the energy resource is stronger. Dimensioning is therefore considered a key stage when a design project of Wave Energy Converters (WEC) is undertaken. Location, WEC concept, Power Take-Off (PTO) type, control strategy and hydrodynamic resonance considerations are some of the critical aspects to take into account to achieve a good performance. The paper proposes an automatic dimensioning methodology to be accomplished at the initial design project stages and the following elements are described to carry out the study: an optimization design algorithm, its objective functions and restrictions, a PTO model, as well as a procedure to evaluate the WEC energy production. After that, a parametric analysis is included considering different combinations of the key parameters previously introduced. A variety of study cases are analysed from the point of view of energy production for different design-parameters and all of them are compared with a reference case. Finally, a discussion is presented based on the results obtained, and some recommendations to face the WEC design stage are given

Evaluation of the Magnetic Field Generated by the Inverter of an Electric Vehicle

In hybrid and electric vehicles, passengers sit very close to an electric system of significant power, which means that they may be subjected to high electromagnetic fields. The hazards of long-term exposure to these fields must be taken into account when designing electric vehicles and their components. Among all the electric devices present in the power train, the electronic converter is the most difficult to analyze, given that it works with different frequencies. In this paper, a methodology to evaluate the magnetic field created by a power electronics converter is proposed. After a brief overview of the recommendations of electromagnetic fields exposure, the magnetic field produced by an inverter is analyzed using finite element techniques. The results obtained are compared to laboratory measurements, taken from a real inverter, in order to validate the model. Finally, results are used to draw some conclusions regarding vehicle design criteria and magnetic shielding efficiency