Fast ignition by quasimonoenergetic ion beams

The potential of quasimonoenergetic ion beams for fast ignition (FI) of fusion targets is investigated. Lithium, carbon, aluminium and vanadium ions have been considered here to determine the optimal kinetic energy for each ion type. Our calculations show that the ignition energies of those beams impinging on a standard fuel configuration are similar. However, they are obtained for very different ion energies. Assuming that the ions can be focused onto 10 ?m spots, a new irradiation scheme that reduces substantially the ignition energies is proposed. The combination of using intermediate ions, such as 5.5 GeV vanadium, and the new irradiation scheme allows one to reduce the number of ions required for ignition by roughly three orders of magnitude when compared with the standard proton FI scheme.

O 1s excitation and ionization processes in the CO2 molecule studied via detection of low-energy fluorescence emission

Oxygen 1s excitation and ionization processes in the CO2 molecule have been studied with dispersed and non-dispersed fluorescence spectroscopy as well as with the vacuum ultraviolet (VUV) photon?photoion coincidence technique. The intensity of the neutral O emission line at 845 nm shows particular sensitivity to core-to-Rydberg excitations and core?valence double excitations, while shape resonances are suppressed. In contrast, the partial fluorescence yield in the wavelength window 300?650 nm and the excitation functions of selected O+ and C+ emission lines in the wavelength range 400?500 nm display all of the absorption features. The relative intensity of ionic emission in the visible range increases towards higher photon energies, which is attributed to O 1s shake-off photoionization. VUV photon?photoion coincidence spectra reveal major contributions from the C+ and O+ ions and a minor contribution from C2+. No conclusive changes in the intensity ratios among the different ions are observed above the O 1s threshold. The line shape of the VUV?O+ coincidence peak in the mass spectrum carries some information on the initial core excitation

Hybrid Monte Carlo dose algorithm for low energy X-rays intraoperative radiation therapy

Low energy X-rays Intra-Operative Radiation Therapy (XIORT) treatment delivered during surgery (ex: INTRABEAM, Carl Zeiss, and Axxent, Xoft) can benefit from accurate and fast dose prediction in a patient 3D volume.

Shower approach in the simulation of ion scattering from solids

An efficient approach for the simulation of ion scattering from solids is proposed. For every encountered atom, we take multiple samples of its thermal displacements among those which result in scattering with high probability to finally reach the detector. As a result, the detector is illuminated by intensive ���showers,��� where each event of detection must be weighted according to the actual probability of the atom displacement. The computational cost of such simulation is orders of magnitude lower than in the direct approach, and a comprehensive analysis of multiple and plural scattering effects becomes possible. We use this method for two purposes. First, the accuracy of the approximate approaches, developed mainly for ion-beam structural analysis, is verified. Second, the possibility to reproduce a wide class of experimental conditions is used to analyze some basic features of ion-solid collisions: the role of double violent collisions in low-energy ion scattering; the origin of the ���surface peak��� in scattering from amorphous samples; the low-energy tail in the energy spectra of scattered medium-energy ions due to plural scattering; and the degradation of blocking patterns in two-dimensional angular distributions with increasing depth of scattering. As an example of simulation for ions of MeV energies, we verify the time reversibility for channeling and blocking of 1-MeV protons in a W crystal. The possibilities of analysis that our approach offers may be very useful for various applications, in particular, for structural analysis with atomic resolution.

Wake up Radio Architecture for Wireless Sensor Networks Using an Ultra Low Power FPGA

In this paper an implementation of a Wake up Radio(WuR) with addressing capabilities based on an ultra low power FPGA for ultra low energy Wireless Sensor Networks (WSNs) is proposed. The main goal is to evaluate the utilization of very low power configurable devices to take advantage of their speed, flexibility and low power consumption instead of the traditional approaches based on ASICs or microcontrollers, for communication frame decoding and communication data control.

Ultra Low Power FPGA-Based Architecture for Wake-up Radio in Wireless Sensor Networks

In this paper the capabilities of ultra low power FPGAs to implement Wake-up Radios (WuR) for ultra low energy Wireless Sensor Networks (WSNs) are analyzed. The main goal is to evaluate the utilization of very low power configurable devices to take advantage of their speed, flexibility and low power consumption instead of the more common approaches based on ASICs or microcontrollers. In this context, energy efficiency is a key aspect, considering that usually the instant power consumption is considered a figure of merit, more than the total energy consumed by the application.

Ultraintense lasers applied to laser fusion material testing: production of ions, X rays and neutrons

Due to the particular characteristics of the fusion products, i.e. very short pulses (less than a few ��s long for ions when arriving to the walls; less than 1 ns long for X-rays), very high fluences ( 10 13 particles/cm 2 for both ions and X rays photons) and broad particle energy spectra (up to 10 MeV ions and 100 keV photons), the laser fusion community lacks of facilities to accurately test plasma facing materials under those conditions. In the present work, the ability of ultraintese lasers to create short pulses of energetic particles and high fluences is addressed as a solution to reproduce those ion and X-ray bursts. Based on those parameters, a comparison between fusion ion and laser driven ion beams is presented and discussed, describing a possible experimental set-up to generate with lasers the appropriate ion pulses. At the same time, the possibility of generating X-ray or neutron beams which simulate those of laser fusion environments is also indicated and assessed under current laser intensities. It is concluded that ultraintense lasers should play a relevant role in the validation of materials for laser fusion facilities.

Vulnerability analysis of RC buildings with wide beams located in moderate seismicity regions

A significant number of short-to-mid height RC buildings with wide beams have been constructed in areas of moderate seismicity of Spain, mainly for housing and administrative use. The buildings have a framed structure with one-way slabs; the wide beams constitute the distinctive characteristic, their depth being equal to that of the rest of the slab, thus providing a flat lower surface, convenient for construction and the layout of facilities. Seismic behavior in the direction of the wide beams appears to be deficient because of: (i) low lateral strength, mainly because of the small effective depth of the beams, (ii) inherent low ductility of the wide beams, generated by high amount of reinforcement, (iii) the big strut compressive forces developed inside the column-beam connections due to the low height of the beams, and (iv) the fact that the wide beams are wider than the columns, meaning that the contribution of the outer zones to the resistance of the beam-column joints is unreliable because there is no torsion reinforcement. In the orthogonal direction, the behavior is worse since the only members of the slabs that contribute to the lateral resistance are the joists and the fa��ade beams. Moreover, these buildings were designed with codes that did not include ductility requirements and required only a low lateral resistance; indeed, in many cases, seismic action was not considered at all. Consequently, the seismic capacity of these structures is not reliable. The objective of this research is to assess numerically this capability, whereas further research will aim to propose retrofit strategies. The research approach consists of: (i) selecting a number of 3-story and 6-story buildings that represent the vast majority of the existing ones and (ii) evaluating their vulnerability through three types of analyses, namely: code-type, push-over and nonlinear dynamic analysis. Given the low lateral resistance of the main frames, the cooperation of the masonry infill walls is accounted for; for each representative building, three wall densities are considered. The results of the analyses show that the buildings in question exhibit inadequate seismic behavior in most of the examined situations. In general, the relative performance is less deficient for Target Drift CP (Collapse Prevention) than for IO (Immediate Occupancy). Since these buildings are selected to be representative of the vast majority of buildings with wide beams that were constructed in Spain without accounting for any seismic consideration, our conclusions can be extrapolated to a broader scenario.

High power beam dump project for the accelerator prototype LIPAc: Cooling design and analysis

En el campo de la fusi��n nuclear y desarroll��ndose en paralelo a ITER (International Thermonuclear Experimental Reactor), el proyecto IFMIF (International Fusion Material Irradiation Facility) se enmarca dentro de las actividades complementarias encaminadas a solucionar las barreras tecnol��gicas que a��n plantea la fusi��n. En concreto IFMIF es una instalaci��n de irradiaci��n cuya misi��n es caracterizar materiales resistentes a condiciones extremas como las esperadas en los futuros reactores de fusi��n como DEMO (DEMOnstration power plant). Consiste de dos aceleradores de deuterones que proporcionan un haz de 125 mA y 40 MeV cada uno, que al colisionar con un blanco de litio producen un flujo neutr��nico intenso (1017 neutrones/s) con un espectro similar al de los neutrones de fusi��n [1], [2]. Dicho flujo neutr��nico es empleado para irradiar los diferentes materiales candidatos a ser empleados en reactores de fusi��n, y las muestras son posteriormente examinadas en la llamada instalaci��n de post-irradiaci��n. Como primer paso en tan ambicioso proyecto, una fase de validaci��n y dise��o llamada IFMIFEVEDA (Engineering Validation and Engineering Design Activities) se encuentra actualmente en desarrollo. Una de las actividades contempladas en esta fase es la construcci��n y operaci��n de una acelarador prototipo llamado LIPAc (Linear IFMIF Prototype Accelerator). Se trata de un acelerador de deuterones de alta intensidad id��ntico a la parte de baja energ��a de los aceleradores de IFMIF. Los componentes del LIPAc, que ser�� instalado en Jap��n, son suministrados por diferentes pa��ses europeos. El acelerador proporcionar�� un haz continuo de deuterones de 9 MeV con una potencia de 1.125 MW que tras ser caracterizado con diversos instrumentos deber�� pararse de forma segura. Para ello se requiere un sistema denominado bloque de parada (Beam Dump en ingl��s) que absorba la energ��a del haz y la transfiera a un sumidero de calor. Espa��a tiene el compromiso de suministrar este componente y CIEMAT (Centro de Investigaciones Energ��ticas Medioambientales y Tecnol��gicas) es responsable de dicha tarea. La pieza central del bloque de parada, donde se para el haz de iones, es un cono de cobre con un ��ngulo de 3.5o, 2.5 m de longitud y 5 mm de espesor. Dicha pieza est�� refrigerada por agua que fluye en su superficie externa por el canal que se forma entre el cono de cobre y otra pieza conc��ntrica con ��ste. Este es el marco en que se desarrolla la presente tesis, cuyo objeto es el dise��o del sistema de refrigeraci��n del bloque de parada del LIPAc. El dise��o se ha realizado utilizando un modelo simplificado unidimensional. Se han obtenido los par��metros del agua (presi��n, caudal, p��rdida de carga) y la geometr��a requerida en el canal de refrigeraci��n (anchura, rugosidad) para garantizar la correcta refrigeraci��n del bloque de parada. Se ha comprobado que el dise��o permite variaciones del haz respecto a la situaci��n nominal siendo el flujo cr��tico calor��fico al menos 2 veces superior al nominal. Se han realizado asimismo simulaciones fluidodin��micas 3D con ANSYS-CFX en aquellas zonas del canal de refrigeraci��n que lo requieren. El bloque de parada se activar�� como consecuencia de la interacci��n del haz de part��culas lo que impide cualquier cambio o reparaci��n una vez comenzada la operaci��n del acelerador. Por ello el dise��o ha de ser muy robusto y todas las hip��tesis utilizadas en la realizaci��n de ��ste deben ser cuidadosamente comprobadas. Gran parte del esfuerzo de la tesis se centra en la estimaci��n del coeficiente de transferencia de calor que es determinante en los resultados obtenidos, y que se emplea adem��s como condici��n de contorno en los c��lculos mec��nicos. Para ello por un lado se han buscado correlaciones cuyo rango de aplicabilidad sea adecuado para las condiciones del bloque de parada (canal anular, diferencias de temperatura agua-pared de decenas de grados). En un segundo paso se han comparado los coeficientes de pel��cula obtenidos a partir de la correlaci��n seleccionada (Petukhov-Gnielinski) con los que se deducen de simulaciones fluidodin��micas, obteniendo resultados satisfactorios. Por ��ltimo se ha realizado una validaci��n experimental utilizando un prototipo y un circuito hidr��ulico que proporciona un flujo de agua con los par��metros requeridos en el bloque de parada. Tras varios intentos y mejoras en el experimento se han obtenido los coeficientes de pel��cula para distintos caudales y potencias de calentamiento. Teniendo en cuenta la incertidumbre de las medidas, los valores experimentales concuerdan razonablemente bien (en el rango de 15%) con los deducidos de las correlaciones. Por motivos radiol��gicos es necesario controlar la calidad del agua de refrigeraci��n y minimizar la corrosi��n del cobre. Tras un estudio bibliogr��fico se identificaron los par��metros del agua m��s adecuados (conductividad, pH y concentraci��n de ox��geno disuelto). Como parte de la tesis se ha realizado asimismo un estudio de la corrosi��n del circuito de refrigeraci��n del bloque de parada con el doble fin de determinar si puede poner en riesgo la integridad del componente, y de obtener una estimaci��n de la velocidad de corrosi��n para dimensionar el sistema de purificaci��n del agua. Se ha utilizado el c��digo TRACT (TRansport and ACTivation code) adapt��ndalo al caso del bloque de parada, para lo cual se trabaj�� con el responsable (Panos Karditsas) del c��digo en Culham (UKAEA). Los resultados confirman que la corrosi��n del cobre en las condiciones seleccionadas no supone un problema. La Tesis se encuentra estructurada de la siguiente manera: En el primer cap��tulo se realiza una introducci��n de los proyectos IFMIF y LIPAc dentro de los cuales se enmarca esta Tesis. Adem��s se describe el bloque de parada, siendo el dise��o del sistema de rerigeraci��n de ��ste el principal objetivo de la Tesis. En el segundo y tercer cap��tulo se realiza un resumen de la base te��rica as�� como de las diferentes herramientas empleadas en el dise��o del sistema de refrigeraci��n. El cap��tulo cuarto presenta los resultados del relativos al sistema de refrigeraci��n. Tanto los obtenidos del estudio unidimensional, como los obtenidos de las simulaciones fluidodin��micas 3D mediante el empleo del c��digo ANSYS-CFX. En el quinto cap��tulo se presentan los resultados referentes al an��lisis de corrosi��n del circuito de refrigeraci��n del bloque de parada. El cap��tulo seis se centra en la descripci��n del montaje experimental para la obtenci��n de los valores de p��rdida de carga y coeficiente de transferencia del calor. Asimismo se presentan los resultados obtenidos en dichos experimentos. Finalmente encontramos un cap��tulo de ap��ndices en el que se describen una serie de experimentos llevados a cabo como pasos intermedios en la obtenci��n del resultado experimental del coeficiente de pel��cula. Tambi��n se presenta el c��digo inform��tico empleado para el an��lisis unidimensional del sistema de refrigeraci��n del bloque de parada llamado CHICA (Cooling and Heating Interaction and Corrosion Analysis). ABSTRACT In the nuclear fusion field running in parallel to ITER (International Thermonuclear Experimental Reactor) as one of the complementary activities headed towards solving the technological barriers, IFMIF (International Fusion Material Irradiation Facility) project aims to provide an irradiation facility to qualify advanced materials resistant to extreme conditions like the ones expected in future fusion reactors like DEMO (DEMOnstration Power Plant). IFMIF consists of two constant wave deuteron accelerators delivering a 125 mA and 40 MeV beam each that will collide on a lithium target producing an intense neutron fluence (1017 neutrons/s) with a similar spectra to that of fusion neutrons [1], [2]. This neutron flux is employed to irradiate the different material candidates to be employed in the future fusion reactors, and the samples examined after irradiation at the so called post-irradiative facilities. As a first step in such an ambitious project, an engineering validation and engineering design activity phase called IFMIF-EVEDA (Engineering Validation and Engineering Design Activities) is presently going on. One of the activities consists on the construction and operation of an accelerator prototype named LIPAc (Linear IFMIF Prototype Accelerator). It is a high intensity deuteron accelerator identical to the low energy part of the IFMIF accelerators. The LIPAc components, which will be installed in Japan, are delivered by different european countries. The accelerator supplies a 9 MeV constant wave beam of deuterons with a power of 1.125 MW, which after being characterized by different instruments has to be stopped safely. For such task a beam dump to absorb the beam energy and take it to a heat sink is needed. Spain has the compromise of delivering such device and CIEMAT (Centro de Investigaciones Energ��ticas Medioambientales y Tecnol��gicas) is responsible for such task. The central piece of the beam dump, where the ion beam is stopped, is a copper cone with an angle of 3.5o, 2.5 m long and 5 mm width. This part is cooled by water flowing on its external surface through the channel formed between the copper cone and a concentric piece with the latter. The thesis is developed in this realm, and its objective is designing the LIPAc beam dump cooling system. The design has been performed employing a simplified one dimensional model. The water parameters (pressure, flow, pressure loss) and the required annular channel geometry (width, rugoisty) have been obtained guaranteeing the correct cooling of the beam dump. It has been checked that the cooling design allows variations of the the beam with respect to the nominal position, being the CHF (Critical Heat Flux) at least twice times higher than the nominal deposited heat flux. 3D fluid dynamic simulations employing ANSYS-CFX code in the beam dump cooling channel sections which require a more thorough study have also been performed. The beam dump will activateasaconsequenceofthe deuteron beam interaction, making impossible any change or maintenance task once the accelerator operation has started. Hence the design has to be very robust and all the hypotheses employed in the design mustbecarefully checked. Most of the work in the thesis is concentrated in estimating the heat transfer coefficient which is decisive in the obtained results, and is also employed as boundary condition in the mechanical analysis. For such task, correlations which applicability range is the adequate for the beam dump conditions (annular channel, water-surface temperature differences of tens of degrees) have been compiled. In a second step the heat transfer coefficients obtained from the selected correlation (Petukhov- Gnielinski) have been compared with the ones deduced from the 3D fluid dynamic simulations, obtaining satisfactory results. Finally an experimental validation has been performed employing a prototype and a hydraulic circuit that supplies a flow with the requested parameters in the beam dump. After several tries and improvements in the experiment, the heat transfer coefficients for different flows and heating powers have been obtained. Considering the uncertainty in the measurements the experimental values agree reasonably well (in the order of 15%) with the ones obtained from the correlations. Due to radiological reasons the quality of the cooling water must be controlled, hence minimizing the copper corrosion. After performing a bibligraphic study the most adequate water parameters were identified (conductivity, pH and dissolved oxygen concentration). As part of this thesis a corrosion study of the beam dump cooling circuit has been performed with the double aim of determining if corrosion can pose a risk for the copper beam dump , and obtaining an estimation of the corrosion velocitytodimension the water purification system. TRACT code(TRansport and ACTivation) has been employed for such study adapting the code for the beam dump case. For such study a collaboration with the code responsible (Panos Karditsas) at Culham (UKAEA) was established. The work developed in this thesis has supposed the publication of three articles in JCR journals (���Journal of Nuclear Materials��� y ���Fusion Engineering and Design���), as well as presentations in more than four conferences and relevant meetings.

Fast ignition driven by quasi-monoenergetic ions: Optimal ion type and reduction of ignition energies with an ion beam array

Fast ignition of inertial fusion targets driven by quasi-monoenergetic ion beams is investigated by means of numerical simulations. Light and intermediate ions such as lithium, carbon, aluminum and vanadium have been considered. Simulations show that the minimum ignition energies of an ideal configuration of compressed Deuterium-Tritium are almost independent on the ion atomic number. However, they are obtained for increasing ion energies, which scale, approximately, as Z2, where Z is the ion atomic number. Assuming that the ion beam can be focused into 10 ?m spots, a new irradiation scheme is proposed to reduce the ignition energies. The combination of intermediate Z ions, such as 5.5 GeV vanadium, and the new irradiation scheme allows a reduction of the number of ions required for ignition by, roughly, three orders of magnitude when compared with the standard proton fast ignition scheme.

Energy efficiency evaluation of zero energy houses

Given the global energy and environmental situation, the European Union has been issuing directives with increasingly demanding requirements in term of the energy efficiency in buildings. The international competition of sustainable houses, Solar Decathlon Europe (SDE), is aligned with these European objectives. SDE houses are low energy solar buildings that must reach the near to zero energy houses��� goal. In the 2012 edition, in order to emphasize its significance, the Energy Efficiency Contest was added. SDE houses��� interior comfort, functioning and energy performance is monitored. The monitoring data can give an idea about the efficiency of the houses. However, a jury comprised by international experts is responsible for carrying out the houses energy efficiency evaluation. Passive strategies and houses services are analyzed. Additionally, the jury's assessment has been compared with the behavior of the houses during the monitoring period. Comparative studies make emphasis on the energy aspects, houses functioning and their interior comfort. Conclusions include thoughts related with the evaluation process, the results of the comparative studies and suggestions for the next competitions.

Effect of level of fiber of the rearing phase diets on egg production, digestive tract traits, and body measurements of brown egg-laying hens fed diets differing in energy concentration

This research studied the effects of additional fiber in the rearing phase diets on egg production, gastrointestinal tract (GIT) traits, and body measurements of brown egg-laying hens fed diets varying in energy concentration from 17 to 46 wk of age. The experiment was completely randomized with 10 treatments arranged as a 5 �� 2 factorial with 5 rearing phase diets and 2 laying phase diets. During the rearing phase, treatments consisted of a control diet based on cereals and soybean meal and 4 additional diets with a combination of 2 fiber sources (cereal straw and sugar beet pulp, SBP) at 2 levels (2 and 4%). During the laying phase, diets differed in energy content (2,650 vs. 2,750 kcal AMEn/kg) but had the same amino acid content per unit of energy. The rearing diet did not affect any production trait except egg production that was lower in birds fed SBP than in birds fed straw (91.6 and 94.1%, respectively; P < 0.05). Laying hens fed the high energy diet had lower feed intake (P < 0.001), better feed conversion (P < 0.01), and greater BW gain (P < 0.05) than hens fed the low energy diet but egg production and egg weight were not affected. At 46 wk of age, none of the GIT traits was affected by previous dietary treatment. At this age, hen BW was positively related with body length (r = 0.500; P < 0.01), tarsus length (r = 0.758; P < 0.001), and body mass index (r = 0.762; P < 0.001) but no effects of type of diet on these traits were detected. In summary, the inclusion of up to 4% of a fiber source in the rearing diets did not affect GIT development of the hens but SBP reduced egg production. An increase in the energy content of the laying phase diet reduced ADFI and improved feed efficiency but did not affect any of the other traits studied.