Hydrodynamic stability theory of double ablation front structures in inertial confinement fusion.

The aim of inertial confinement fusion is the production of energy by the fusion of thermonuclear fuel (deuterium-tritium) enclosed in a spherical target due to its implosion. In the direct-drive approach, the energy needed to spark fusion reactions is delivered by the irradiation of laser beams that leads to the ablation of the outer shell of the target (the so-called ablator). As a reaction to this ablation process, the target is accelerated inwards, and, provided that this implosion is sufficiently strong a symmetric, the requirements of temperature and pressure in the center of the target are achieved leading to the ignition of the target (fusion). One of the obstacles capable to prevent appropriate target implosions takes place in the ablation region where any perturbation can grow even causing the ablator shell break, due to the ablative Rayleigh-Taylor instability. The ablative Rayleigh-Taylor instability has been extensively studied throughout the last 40 years in the case where the density/temperature profiles in the ablation region present a single front (the ablation front). Single ablation fronts appear when the ablator material has a low atomic number (deuterium/tritium ice, plastic). In this case, the main mechanism of energy transport from the laser energy absorption region (low density plasma) to the ablation region is the electron thermal conduction. However, recently, the use of materials with a moderate atomic number (silica, doped plastic) as ablators, with the aim of reducing the target pre-heating caused by suprathermal electrons generated by the laser-plasma interaction, has demonstrated an ablation region composed of two ablation fronts. This fact appears due to increasing importance of radiative effects in the energy transport. The linear theory describing the Rayleigh-Taylor instability for single ablation fronts cannot be applied for the stability analysis of double ablation front structures. Therefore, the aim of this thesis is to develop, for the first time, a linear stability theory for this type of hydrodynamic structures.

Deep levels in a-plane, high Mg-content MgxZn1-xO epitaxial layers grown by molecular beam epitaxy

Deep level defects in n-type unintentionally doped a-plane MgxZn1���xO, grown by molecular beam epitaxy on r-plane sapphire were fully characterized using deep level optical spectroscopy (DLOS) and related methods. Four compositions of MgxZn1���xO were examined with x���=���0.31, 0.44, 0.52, and 0.56 together with a control ZnO sample. DLOS measurements revealed the presence of five deep levels in each Mg-containing sample, having energy levels of Ec���������1.4���eV, 2.1���eV, 2.6���V, and Ev���+���0.3���eV and 0.6���eV. For all Mg compositions, the activation energies of the first three states were constant with respect to the conduction band edge, whereas the latter two revealed constant activation energies with respect to the valence band edge. In contrast to the ternary materials, only three levels, at Ec���������2.1���eV, Ev���+���0.3���eV, and 0.6���eV, were observed for the ZnO control sample in this systematically grown series of samples. Substantially higher concentrations of the deep levels at Ev���+���0.3���eV and Ec���������2.1���eV were observed in ZnO compared to the Mg alloyed samples. Moreover, there is a general invariance of trap concentration of the Ev���+���0.3���eV and 0.6���eV levels on Mg content, while at least and order of magnitude dependency of the Ec���������1.4���eV and Ec���������2.6���eV levels in Mg alloyed samples.

Band gap control via tuning of inversion degree in CdIn2S4 spinel

Based on theoretical arguments, we propose a possible route for controlling the band-gap in the promising photovoltaic material CdIn2S4. Our ab initio calculations show that the experimental degree of inversion in this spinel (fraction of tetrahedral sites occupied by In) corresponds approximately to the equilibrium value given by the minimum of the theoretical inversion free energy at a typical synthesis temperature. Modification of this temperature, or of the cooling rate after synthesis, is then expected to change the inversion degree, which in turn sensitively tunes the electronic band-gap of the solid, as shown here by screened hybrid functional calculations.

EPIC (Entorno de P��ncreas Artificial con Interfaz Cl��nica)

La Diabetes Mellitus se define como el trastorno del metabolismo de los carbohidratos, resultante de una producci��n insuficiente o nula de insulina en las c��lulas beta del p��ncreas, o la manifestaci��n de una sensibilidad reducida a la insulina por parte del sistema metab��lico. La diabetes tipo 1 se caracteriza por la nula producci��n de insulina por la destrucci��n de las c��lulas beta del p��ncreas. Si no hay insulina en el torrente sangu��neo, la glucosa no puede ser absorbida por las c��lulas, produci��ndose un estado de hiperglucemia en el paciente, que a medio y largo plazo si no es tratado puede ocasionar severas enfermedades, conocidos como s��ndromes de la diabetes. La diabetes tipo 1 es una enfermedad incurable pero controlable. La terapia para esta enfermedad consiste en la aplicaci��n ex��gena de insulina con el objetivo de mantener el nivel de glucosa en sangre dentro de los l��mites normales. Dentro de las m��ltiples formas de aplicaci��n de la insulina, en este proyecto se usar�� una bomba de infusi��n, que unida a un sensor subcut��neo de glucosa permitir�� crear un lazo de control aut��nomo que regule la cantidad optima de insulina aplicada en cada momento. Cuando el algoritmo de control se utiliza en un sistema digital, junto con el sensor subcut��neo y bomba de infusi��n subcut��nea, se conoce como p��ncreas artificial endocrino (PAE) de uso ambulatorio, hoy d��a todav��a en fase de investigaci��n. Estos algoritmos de control metab��lico deben de ser evaluados en simulaci��n para asegurar la integridad f��sica de los pacientes, por lo que es necesario dise��ar un sistema de simulaci��n mediante el cual asegure la fiabilidad del PAE. Este sistema de simulaci��n conecta los algoritmos con modelos metab��licos matem��ticos para obtener una visi��n previa de su funcionamiento. En este escenario se dise���� DIABSIM, una herramienta desarrollada en LabViewTM, que posteriormente se traslad�� a MATLABTM, y basada en el modelo matem��tico compartimental propuesto por Hovorka, con la que poder simular y evaluar distintos tipos de terapias y reguladores en lazo cerrado. Para comprobar que estas terapias y reguladores funcionan, una vez simulados y evaluados, se tiene que pasar a la experimentaci��n real a trav��s de un protocolo de ensayo cl��nico real, como paso previo al PEA ambulatorio. Para poder gestionar este protocolo de ensayo cl��nico real para la verificaci��n de los algoritmos de control, se cre�� una interfaz de usuario a trav��s de una serie de funciones de simulaci��n y evaluaci��n de terapias con insulina realizadas con MATLABTM (GUI: Graphics User Interface), conocido como Entorno de P��ncreas artificial con Interfaz Cl��nica (EPIC). EPIC ha sido ya utilizada en 10 ensayos cl��nicos de los que se han ido proponiendo posibles mejoras, ampliaciones y/o cambios. Este proyecto propone una versi��n mejorada de la interfaz de usuario EPIC propuesta en un proyecto anterior para gestionar un protocolo de ensayo cl��nico real para la verificaci��n de algoritmos de control en un ambiente hospitalario muy controlado, adem��s de estudiar la viabilidad de conectar el GUI con SimulinkTM (entorno gr��fico de Matlab de simulaci��n de sistemas) para su conexi��n con un nuevo simulador de pacientes aprobado por la JDRF (Juvenil Diabetes Research Foundation). SUMMARY The diabetes mellitus is a metabolic disorder of carbohydrates, as result of an insufficient or null production of insulin in the beta cellules of pancreas, or the manifestation of a reduced sensibility to the insulin from the metabolic system. The type 1 diabetes is characterized for a null production of insulin due to destruction of the beta cellules. Without insulin in the bloodstream, glucose can���t be absorbed by the cellules, producing a hyperglycemia state in the patient and if pass a medium or long time and is not treated can cause severe disease like diabetes syndrome. The type 1 diabetes is an incurable disease but controllable one. The therapy for this disease consists on the exogenous insulin administration with the objective to maintain the glucose level in blood within the normal limits. For the insulin administration, in this project is used an infusion pump, that permit with a subcutaneous glucose sensor, create an autonomous control loop that regulate the optimal insulin amount apply in each moment. When the control algorithm is used in a digital system, with the subcutaneous senor and infusion subcutaneous pump, is named as ���Artificial Endocrine Pancreas��� for ambulatory use, currently under investigate. These metabolic control algorithms should be evaluates in simulation for assure patients��� physical integrity, for this reason is necessary to design a simulation system that assure the reliability of PAE. This simulation system connects algorithms with metabolic mathematics models for get a previous vision of its performance. In this scenario was created DIABSIMTM, a tool developed in LabView, that later was converted to MATLABTM, and based in the compartmental mathematic model proposed by Hovorka that could simulate and evaluate several different types of therapy and regulators in closed loop. To check the performance of these therapies and regulators, when have been simulated and evaluated, will be necessary to pass to real experimentation through a protocol of real clinical test like previous step to ambulatory PEA. To manage this protocol was created an user interface through the simulation and evaluation functions od therapies with insulin realized with MATLABTM (GUI: Graphics User Interface), known as ���Entorno de P��ncreas artificial con Interfaz Cl��nica��� (EPIC).EPIC have been used in 10 clinical tests which have been proposed improvements, adds and changes. This project proposes a best version of user interface EPIC proposed in another project for manage a real test clinical protocol for checking control algorithms in a controlled hospital environment and besides studying viability to connect the GUI with SimulinkTM (Matlab graphical environment in systems simulation) for its connection with a new patients simulator approved for the JDRF (Juvenil Diabetes Research Foundation).

Emulaci��n de instrumentos de sobremesa mediante Tarjetas de Adquisici��n de Datos

Este proyecto se ha enmarcado en la l��nea de desarrollo del Laboratorio Virtual de electr��nica, desarrollado en la Escuela Universitaria de Ingenier��a T��cnica de Telecomunicaci��n (EUITT), de la Universidad Polit��cnica de Madrid (UPM). Con el Laboratorio Virtual los alumnos de la universidad, de cualquiera de las escuelas de ingenier��a que la componen, pueden realizar pr��cticas de forma remota. Es decir, desde cualquier PC con el software adecuado instalado y a trav��s de Internet, sin requerir su presencia en un laboratorio f��sico. La caracter��stica m��s destacable e importante de este Laboratorio Virtual es que las medidas que se realizan no son simulaciones sobre circuitos virtuales, sino medidas reales sobre circuitos reales: el alumno puede configurar una serie de interconexiones entre componentes electr��nicos, formando el circuito que necesite, que posteriormente el Laboratorio Virtual se encargar�� de realizar f��sicamente, gracias al hardware y al software que conforman el sistema. Tras ello, el alumno puede excitar el circuito con se��ales provenientes de instrumental real de laboratorio y obtener medidas de la misma forma, en los puntos del circuito que indique. La necesidad principal a la que este Proyecto de Fin de Carrera da soluci��n es la sustituci��n de los instrumentos de sobremesa por instrumentos emulados en base a Tarjetas de Adquisici��n de Datos (DAQ). Los instrumentos emulados son: un mult��metro, un generador de se��ales y un osciloscopio. Adem��s, existen otros objetivos derivados de lo anterior, como es el que los instrumentos emulados deben guardar una total compatibilidad con el resto del sistema del Laboratorio Virtual, o que el dise��o ha de ser escalable y adaptable. Todo ello se ha implementado mediante: un software escrito en LabVIEW, que utiliza un lenguaje de programaci��n gr��fico; un hardware que ha sido primero dise��ado y luego fabricado, controlado por el software; y una Tarjeta de Adquisici��n de Datos, que gracias a la escalabilidad del sistema puede sustituirse por otro modelo superior o incluso por varias de ellas. ABSTRACT. This project is framed in the development line of the electronics Virtual Laboratory, developed at Escuela Universitaria de Ingenier��a T��cnica de Telecomunicaci��n (EUITT), from Universidad Polit��cnica de Madrid (UPM). With the Virtual Laboratory, the university���s students, from any of its engineering schools that is composed of, can do practices remotely. Or in other words, from any PC with the correct software installed and through the Internet, without requiring his or her presence in a physical laboratory. The most remarkable and important characteristic this Virtual Laboratory has is that the measures the students does are not simulations over virtual circuits, but real measures over real circuits: the student can configure a series of interconnections between electronic parts, setting up the circuit he or she needs, and afterwards the Virtual Laboratory will realize that circuit physically, thanks to the hardware and software that compose the whole system. Then, the student can apply signals coming from real laboratory instruments and get measures in the same way, at the points of the circuit he or she points out. The main need this Degree Final Project gives solution is the substitution of the real instruments by emulated instruments, based on Data Acquisition systems (DAQ). The emulated instruments are: a digital multimeter, a signal generator and an oscilloscope. In addition, there is other objectives coming from the previously said, like the need of a total compatibility between the real instruments and the emulated ones and with the rest of the Virtual Laboratory, or that the design must be scalable and adaptive. All of that is implemented by: a software written in LabVIEW, which makes use of a graphical programming language; a hardware that was first designed and later manufactured, then controlled by software; and a Data Acquisition device, though thanks to the system���s scalability it can be substituted by a better model or even by several DAQs.

Co2 capture in power plants-using the oxy-combustion principle

In the C02 capture from power generation, the energy penalties for the capture are one of the main challenges. Nowadays, the post-combustion methods have energy penalties 10wer than the oxy combustion and pre-combustion technologies. One of the main disadvantages of the post combustion method is the fact that the capture ofC02at atmospheric pressure requires quite big equipment for the high flow rates of flue gas, and the 10w partial pressure of the CO2generates an important 10ss of energy. The A1lam cyc1e presented for NETPOWER gives high efficiencies in the power production and 10w energy penalties. A simulation of this cyc1e is made together with a simulation of power plants with pre-combustion and post-combustion capture and without capture for natural gas and forcoa1. The simulations give 10wer efficiencies than the proposed for NETPOWER For natural gas the efficiency is 52% instead of the 59% presented, and 33% instead of51% in the case of using coal as fuel. Are brought to light problems in the CO2compressor due the high flow ofC02that is compressed unti1300 bar to be recyc1ed into the combustor.

An architecture for a heterogeneous private IaaS management system

Cloud computing and, more particularly, private IaaS, is seen as a mature technology with a myriad solutions tochoose from. However, this disparity of solutions and products has instilled in potential adopters the fear of vendor and data lock-in. Several competing and incompatible interfaces and management styles have given even more voice to these fears. On top of this, cloud users might want to work with several solutions at the same time, an integration that is difficult to achieve in practice. In this paper, we propose a management architecture that tries to tackle these problems; it offers a common way of managing several cloud solutions, and an interface that can be tailored to the needs of the user. This management architecture is designed in a modular way, and using a generic information model. We have validated our approach through the implementation of the components needed for this architecture to support a sample private IaaS solution: OpenStack

Neutronics and activation of the preliminary reaction chamber of HiPER reactor based in a SCLL blanket

The HiPER reactor design is exploring different reaction chambers. In this study, we tackle the neutronicsand activation studies of a preliminary reaction chamber based in the following technologies: unpro-tected dry wall for the First Wall, self-cooled lead lithium blanket, and independent low activation steelVacuum Vessel. The most critical free parameter in this stage is the blanket thickness, as a function ofthe6Li enrichment. After a parametric study, we select for study both a ?thin? and ?thick? blanket, with?high? and ?low?6Li enrichment respectively, to reach a TBR = 1.1. To help to make a choice, we com-pute, for both blanket options, in addition to the TBR, the energy amplification factor, the tritium partialpressure, the203Hg and210Po total activity in the LiPb loop, and the Vacuum Vessel thickness requiredto guarantee the reweldability during its lifetime. The thin blanket shows a superior performance in thesafety related issues and structural viability, but it operates at higher6Li enrichment. It is selected forfurther improvements. The Vacuum Vessel shows to be unviable in both cases, with the thickness varyingbetween 39 and 52 cm. Further chamber modifications, such as the introduction of a neutron reflector,are required to exploit the benefits of the thin blanket with a reasonable Vacuum Vessel.

Ion acceleration in underdense plasmas by ultra-short laser pulses

We report on the ion acceleration mechanisms that occur during the interaction of an intense and ultrashort laser pulse ( �� > �� I 2 1018 W cm���2 m2) with an underdense helium plasma produced from an ionized gas jet target. In this unexplored regime, where the laser pulse duration is comparable to the inverse of the electron plasma frequency ��pe, reproducible non-thermal ion bunches have been measured in the radial direction. The two He ion charge states present energy distributions with cutoff energies between 150 and 200 keV, and a striking energy gap around 50 keV appearing consistently for all the shots in a given density range. Fully electromagnetic particle-in-cell simulations explain the experimental behaviors. The acceleration results from a combination of target normal sheath acceleration and Coulomb explosion of a filament formed around the laser pulse propagation axis

New steps in the development of the second generation TEC GESMEY

The paper shows the results of the new steps that have been done in the development of the tidal energy converter GESMEY. These are the design, construction and trials into the sea of a 1/10 scale prototype and also the construction with the same scale of the buoy BOSCEM, that anchors the device and lets it in the correct work position and depth, along the two directions of the flow that the daily tidal cycle have. Inside the paper is described the objectives and the methodology of the experimental trials that were ca rry out the last summer with the scale prototype. GESMEY is a new type of tidal energy converter (TEC) that has the capability to exploit currents in waters over forty meters by itself and it gets only using its internal ballast system the necessary equilibrium between hy drostatics and hydrodynamics forces to make the emersion and the immersion procedures without any other help. Finally the paper shows the description of the results obtained over the performance of the devices along the immersion, emersion and floating transport manoeuvres and afterwards the results, that were obtained along the generation power tests that were carried out, are shown.

Development of a management system for virtual machines on private clouds

Cloud computing and, more particularly, private IaaS, is seen as a mature technol- ogy with a myriad solutions to choose from. However, this disparity of solutions and products has instilled in potential adopters the fear of vendor and data lock- in. Several competing and incompatible interfaces and management styles have increased even more these fears. On top of this, cloud users might want to work with several solutions at the same time, an integration that is difficult to achieve in practice. In this Master Thesis I propose a management architecture that tries to solve these problems; it provides a generalized control mechanism for several cloud infrastructures, and an interface that can meet the requirements of the users. This management architecture is designed in a modular way, and using a generic infor- mation model. I have validated the approach through the implementation of the components needed for this architecture to support a sample private IaaS solution: OpenStack.

X-ray microtomography analysis of the damage micromechanisms in 3D woven composites under low-velocity impact

3D woven composites reinforced with either S2 glass, carbon or a hybrid combination of both and containing either polyethylene or carbon z-yarns were tested under low-velocity impact. Different impact energies (in the range of 21���316 J) were used and the mechanical response (in terms of the impact strength and energy dissipated) was compared with that measured in high-performance, albeit standard, 2D laminates. It was found that the impact strength in both 2D and 3D materials was mainly dependent on the in-plane fiber fracture. Conversely, the energy absorption capability was primarily influenced by the presence of z-yarns, having the 3D composites dissipated over twice the energy than the 2D laminates, irrespective of their individual characteristics (fiber type, compaction degree, porosity, etc.). X-ray microtomography revealed that this improvement was due to the z-yarns, which delayed delamination and maintained the structural integrity of the laminate, promoting energy dissipation by tow splitting, intensive fiber breakage under the tup and formation of a plug by out-of-plane shear.

Positional Accuracy in Smart-Phones and Its Effect on LBS Applications.

Location-based services (LBS) highly rely on the location of the mobile user in order to provide the service tailored to that location. This location is calculated differently depending on the technology available in the used mobile device. No matter which technology is used, the location will never be calculated 100% correctly; instead there will always be a margin of error generated during the calculation, which is referred to as positional accuracy. This research has reviewed the eight most common positioning technologies available in the major current smart-phones and assessed their positional accuracy with respect to its usage by LBS applications. Given the vast majority of these applications, this research classified them into thirteen categories, and these categories were also classified depending on their level criticality as low, medium, or high critical, and whether they function indoor or outdoor. The accuracies of different positioning technologies are compared to these two criteria. Low critical outdoor and high critical indoor applications were found technologically covered; high and medium critical outdoor ones weren?t fully resolved. Finally three potential solutions are suggested to be implemented in future smartphones to resolve this technological gap: Real-Time Kinematics Global Positioning System (RTK GPS), terrestrial transmitters, and combination of Wireless Sensors Network and Radio Frequency Identification (WSN-RFID).

Dual Active Bridge based Battery Charger for Plug-in Hybrid Electric Vehicle with Charging Current Containing Low Frequency Ripple

High power density is strongly preferable for the on-board battery charger of Plug-in Hybrid Electric Vehicle (PHEV). Wide band gap devices, such as Gallium Nitride HEMTs are being explored to push to higher switching frequency and reduce passive component size. In this case, the bulk DC link capacitor of AC-DC Power Factor Correction (PFC) stage, which is usually necessary to store ripple power of two times the line frequency in a DC current charging system, becomes a major barrier on power density. If low frequency ripple is allowed in the battery, the DC link capacitance can be significantly reduced. This paper focuses on the operation of a battery charging system, which is comprised of one Full Bridge (FB) AC-DC stage and one Dual Active Bridge (DAB) DC-DC stage, with charging current containing low frequency ripple at two times line frequency, designated as sinusoidal charging. DAB operation under sinusoidal charging is investigated. Two types of control schemes are proposed and implemented in an experimental prototype. It is proved that closed loop current control is the better. Full system test including both FB AC-DC stage and DAB DC-DC stage verified the concept of sinusoidal charging, which may lead to potentially very high power density battery charger for PHEV.

Obtaining an intermediate band photovoltaic material through the Bi insertion in CdTe

Defect interaction can take place in CdTe under Te and Bi rich conditions. We demonstrate in this work through first principles calculations, that this phenomenon allows a Jahn Teller distortion to form an isolated half-filled intermediate band in the host semiconductor band-gap. This delocalized energy band supports the experimental deep level reported in the host band-gap of CdTe at a low bismuth concentration. Furthermore, the calculated optical absorption of CdTe:Bi in this work shows a significant subband-gap absorption that also supports the enhancement of the optical absorption found in the previous experimental results.