Implementation of the Heated Pulsed Theory using actively heated fiber optics: measurements of soil volumetric water content and soil volumetric heat capacity

Existe una creciente necesidad de hacer el mejor uso del agua para regadío. Una alternativa eficiente consiste en la monitorización del contenido volumétrico de agua (θ), utilizando sensores de humedad. A pesar de existir una gran diversidad de sensores y tecnologías disponibles, actualmente ninguna de ellas permite obtener medidas distribuidas en perfiles verticales de un metro y en escalas laterales de 0.1-1,000 m. En este sentido, es necesario buscar tecnologías alternativas que sirvan de puente entre las medidas puntuales y las escalas intermedias. Esta tesis doctoral se basa en el uso de Fibra Óptica (FO) con sistema de medida de temperatura distribuida (DTS), una tecnología alternativa de reciente creación que ha levantado gran expectación en las últimas dos décadas. Específicamente utilizamos el método de fibra calentada, en inglés Actively Heated Fiber Optic (AHFO), en la cual los cables de Fibra Óptica se utilizan como sondas de calor mediante la aplicación de corriente eléctrica a través de la camisa de acero inoxidable, o de un conductor eléctrico simétricamente posicionado, envuelto, alrededor del haz de fibra óptica. El uso de fibra calentada se basa en la utilización de la teoría de los pulsos de calor, en inglés Heated Pulsed Theory (HPP), por la cual el conductor se aproxima a una fuente de calor lineal e infinitesimal que introduce calor en el suelo. Mediante el análisis del tiempo de ocurrencia y magnitud de la respuesta térmica ante un pulso de calor, es posible estimar algunas propiedades específicas del suelo, tales como el contenido de humedad, calor específico (C) y conductividad térmica. Estos parámetros pueden ser estimados utilizando un sensor de temperatura adyacente a la sonda de calor [método simple, en inglés single heated pulsed probes (SHPP)], ó a una distancia radial r [método doble, en inglés dual heated pulsed probes (DHPP)]. Esta tesis doctoral pretende probar la idoneidad de los sistemas de fibra óptica calentada para la aplicación de la teoría clásica de sondas calentadas. Para ello, se desarrollarán dos sistemas FO-DTS. El primero se sitúa en un campo agrícola de La Nava de Arévalo (Ávila, España), en el cual se aplica la teoría SHPP para estimar θ. El segundo sistema se desarrolla en laboratorio y emplea la teoría DHPP para medir tanto θ como C. La teoría SHPP puede ser implementada con fibra óptica calentada para obtener medidas distribuidas de θ, mediante la utilización de sistemas FO-DTS y el uso de curvas de calibración específicas para cada suelo. Sin embargo, la mayoría de aplicaciones AHFO se han desarrollado exclusivamente en laboratorio utilizando medios porosos homogéneos. En esta tesis se utiliza el programa Hydrus 2D/3D para definir tales curvas de calibración. El modelo propuesto es validado en un segmento de cable enterrado en una instalación de fibra óptica y es capaz de predecir la respuesta térmica del suelo en puntos concretos de la instalación una vez que las propiedades físicas y térmicas de éste son definidas. La exactitud de la metodología para predecir θ frente a medidas puntuales tomadas con sensores de humedad comerciales fue de 0.001 a 0.022 m3 m-3 La implementación de la teoría DHPP con AHFO para medir C y θ suponen una oportunidad sin precedentes para aplicaciones medioambientales. En esta tesis se emplean diferentes combinaciones de cables y fuentes emisoras de calor, que se colocan en paralelo y utilizan un rango variado de espaciamientos, todo ello en el laboratorio. La amplitud de la señal y el tiempo de llegada se han observado como funciones del calor específico del suelo. Medidas de C, utilizando esta metodología y ante un rango variado de contenidos de humedad, sugirieron la idoneidad del método, aunque también se observaron importantes errores en contenidos bajos de humedad de hasta un 22%. La mejora del método requerirá otros modelos más precisos que tengan en cuenta el diámetro del cable, así como la posible influencia térmica del mismo. ABSTRACT There is an increasing need to make the most efficient use of water for irrigation. A good approach to make irrigation as efficient as possible is to monitor soil water content (θ) using soil moisture sensors. Although, there is a broad range of different sensors and technologies, currently, none of them can practically and accurately provide vertical and lateral moisture profiles spanning 0-1 m depth and 0.1-1,000 m lateral scales. In this regard, further research to fulfill the intermediate scale and to bridge single-point measurement with the broaden scales is still needed. This dissertation is based on the use of Fiber Optics with Distributed Temperature Sensing (FO-DTS), a novel approach which has been receiving growing interest in the last two decades. Specifically, we employ the so called Actively Heated Fiber Optic (AHFO) method, in which FO cables are employed as heat probe conductors by applying electricity to the stainless steel armoring jacket or an added conductor symmetrically positioned (wrapped) about the FO cable. AHFO is based on the classic Heated Pulsed Theory (HPP) which usually employs a heat probe conductor that approximates to an infinite line heat source which injects heat into the soil. Observation of the timing and magnitude of the thermal response to the energy input provide enough information to derive certain specific soil thermal characteristics such as the soil heat capacity, soil thermal conductivity or soil water content. These parameters can be estimated by capturing the soil thermal response (using a thermal sensor) adjacent to the heat source (the heating and the thermal sources are mounted together in the so called single heated pulsed probe (SHPP)), or separated at a certain distance, r (dual heated pulsed method (DHPP) This dissertation aims to test the feasibility of heated fiber optics to implement the HPP theory. Specifically, we focus on measuring soil water content (θ) and soil heat capacity (C) by employing two types of FO-DTS systems. The first one is located in an agricultural field in La Nava de Arévalo (Ávila, Spain) and employ the SHPP theory to estimate θ. The second one is developed in the laboratory using the procedures described in the DHPP theory, and focuses on estimating both C and θ. The SHPP theory can be implemented with actively heated fiber optics (AHFO) to obtain distributed measurements of soil water content (θ) by using reported soil thermal responses in Distributed Temperature Sensing (DTS) and with a soil-specific calibration relationship. However, most reported AHFO applications have been calibrated under laboratory homogeneous soil conditions, while inexpensive efficient calibration procedures useful in heterogeneous soils are lacking. In this PhD thesis, we employ the Hydrus 2D/3D code to define these soil-specific calibration curves. The model is then validated at a selected FO transect of the DTS installation. The model was able to predict the soil thermal response at specific locations of the fiber optic cable once the surrounding soil hydraulic and thermal properties were known. Results using electromagnetic moisture sensors at the same specific locations demonstrate the feasibility of the model to detect θ within an accuracy of 0.001 to 0.022 m3 m-3. Implementation of the Dual Heated Pulsed Probe (DPHP) theory for measurement of volumetric heat capacity (C) and water content (θ) with Distributed Temperature Sensing (DTS) heated fiber optic (FO) systems presents an unprecedented opportunity for environmental monitoring. We test the method using different combinations of FO cables and heat sources at a range of spacings in a laboratory setting. The amplitude and phase-shift in the heat signal with distance was found to be a function of the soil volumetric heat capacity (referred, here, to as Cs). Estimations of Cs at a range of θ suggest feasibility via responsiveness to the changes in θ (we observed a linear relationship in all FO combinations), though observed bias with decreasing soil water contents (up to 22%) was also reported. Optimization will require further models to account for the finite radius and thermal influence of the FO cables, employed here as “needle probes”. Also, consideration of the range of soil conditions and cable spacing and jacket configurations, suggested here to be valuable subjects of further study and development.

Vista del arco de triunfo y de la ciudad de Cabanes [Material gráfico] =Vue de l'arc de triomphe et de la ville de Cabanes=View of the triumphal Arch and the city of Cabanes

Estampado en la misma hoja con: "Detalles geometrales del Arco de Cabanes"

Double ion implantation and pulsed laser melting processes for third generation solar cells

In the framework of the third generation of photovoltaic devices, the intermediate band solar cell is one of the possible candidates to reach higher efficiencies with a lower processing cost. In this work, we introduce a novel processing method based on a double ion implantation and, subsequently, a pulsed laser melting (PLM) process to obtain thicker layers of Ti supersaturated Si. We perform ab initio theoretical calculations of Si impurified with Ti showing that Ti in Si is a good candidate to theoretically form an intermediate band material in the Ti supersaturated Si. From time-of-flight secondary ion mass spectroscopy measurements, we confirm that we have obtained a Ti implanted and PLM thicker layer of 135 nm. Transmission electron microscopy reveals a single crystalline structure whilst the electrical characterization confirms the transport properties of an intermediate band material/Si substrate junction. High subbandgap absorption has been measured, obtaining an approximate value of 104 cm−1 in the photons energy range from 1.1 to 0.6 eV.

Detalles geometrales de una mezquita árabe en Sn. Felipe [Material gráfico] = Détails géométraux de l'Arc d'une mosquée arabe à St. Philippe = General deatils of an arabe mosque at St. Philip

Detalles de la fachada, planta y corte transversal

Auscultación de presas de hormigón con láser escáner terrestre y modelización de las deformaciones del paramento

Se está produciendo en la geodesia un cambio de paradigma en la concepción de los modelos digitales del terreno, pasando de diseñar el modelo con el menor número de puntos posibles a hacerlo con cientos de miles o millones de puntos. Este cambio ha sido consecuencia de la introducción de nuevas tecnologías como el escáner láser, la interferometría radar y el tratamiento de imágenes. La rápida aceptación de estas nuevas tecnologías se debe principalmente a la gran velocidad en la toma de datos, a la accesibilidad por no precisar de prisma y al alto grado de detalle de los modelos. Los métodos topográficos clásicos se basan en medidas discretas de puntos que considerados en su conjunto forman un modelo; su precisión se deriva de la precisión en la toma singular de estos puntos. La tecnología láser escáner terrestre (TLS) supone una aproximación diferente para la generación del modelo del objeto observado. Las nubes de puntos, producto del escaneo con TLS, pasan a ser tratadas en su conjunto mediante análisis de áreas, de forma que ahora el modelo final no es el resultado de una agregación de puntos sino la de la mejor superficie que se adapta a las nubes de puntos. Al comparar precisiones en la captura de puntos singulares realizados con métodos taquimétricos y equipos TLS la inferioridad de estos últimos es clara; sin embargo es en el tratamiento de las nubes de puntos, con los métodos de análisis basados en áreas, se han obtenido precisiones aceptables y se ha podido considerar plenamente la incorporación de esta tecnología en estudios de deformaciones y movimientos de estructuras. Entre las aplicaciones del TLS destacan las de registro del patrimonio, registro de las fases en la construcción de plantas industriales y estructuras, atestados de accidentes y monitorización de movimientos del terreno y deformaciones de estructuras. En la auscultación de presas, comparado con la monitorización de puntos concretos dentro, en coronación o en el paramento de la presa, disponer de un modelo continuo del paramento aguas abajo de la presa abre la posibilidad de introducir los métodos de análisis de deformaciones de superficies y la creación de modelos de comportamiento que mejoren la comprensión y previsión de sus movimientos. No obstante, la aplicación de la tecnología TLS en la auscultación de presas debe considerarse como un método complementario a los existentes. Mientras que los péndulos y la reciente técnica basada en el sistema de posicionamiento global diferencial (DGPS) dan una información continua de los movimientos de determinados puntos de la presa, el TLS permite ver la evolución estacional y detectar posibles zonas problemáticas en todo el paramento. En este trabajo se analizan las características de la tecnología TLS y los parámetros que intervienen en la precisión final de los escaneos. Se constata la necesidad de utilizar equipos basados en la medida directa del tiempo de vuelo, también llamados pulsados, para distancias entre 100 m y 300 m Se estudia la aplicación del TLS a la modelización de estructuras y paramentos verticales. Se analizan los factores que influyen en la precisión final, como el registro de nubes, tipo de dianas y el efecto conjunto del ángulo y la distancia de escaneo. Finalmente, se hace una comparación de los movimientos dados por los péndulos directos de una presa con los obtenidos del análisis de las nubes de puntos correspondientes a varias campañas de escaneos de la misma presa. Se propone y valida el empleo de gráficos patrón para relacionar las variables precisión o exactitud con los factores distancia y ángulo de escaneo en el diseño de trabajos de campo. Se expone su aplicación en la preparación del trabajo de campo para la realización de una campaña de escaneos dirigida al control de movimientos de una presa y se realizan recomendaciones para la aplicación de la técnica TLS a grandes estructuras. Se ha elaborado el gráfico patrón de un equipo TLS concreto de alcance medio. Para ello se hicieron dos ensayos de campo en condiciones reales de trabajo, realizando escaneos en todo el rango de distancias y ángulos de escaneo del equipo. Se analizan dos métodos para obtener la precisión en la modelización de paramentos y la detección de movimientos de estos: el método del “plano de mejor ajuste” y el método de la “deformación simulada”. Por último, se presentan los resultados de la comparación de los movimientos estacionales de una presa arco-gravedad entre los registrados con los péndulos directos y los obtenidos a partir de los escaneos realizados con un TLS. Los resultados muestran diferencias de milímetros, siendo el mejor de ellos del orden de un milímetro. Se explica la metodología utilizada y se hacen consideraciones respecto a la densidad de puntos de las nubes y al tamaño de las mallas de triángulos. A shift of paradigm in the conception of the survey digital models is taking place in geodesy, moving from designing a model with the fewer possible number of points to models of hundreds of thousand or million points. This change has happened because of the introduction of new technologies like the laser scanner, the interferometry radar and the processing of images. The fast acceptance of these new technologies has been due mainly to the great speed getting the data, to the accessibility as reflectorless technique, and to the high degree of detail of the models. Classic survey methods are based on discreet measures of points that, considered them as a whole, form a model; the precision of the model is then derived from the precision measuring the single points. The terrestrial laser scanner (TLS) technology supposes a different approach to the model generation of the observed object. Point cloud, the result of a TLS scan, must be treated as a whole, by means of area-based analysis; so, the final model is not an aggregation of points but the one resulting from the best surface that fits with the point cloud. Comparing precisions between the one resulting from the capture of singular points made with tachometric measurement methods and with TLS equipment, the inferiority of this last one is clear; but it is in the treatment of the point clouds, using area-based analysis methods, when acceptable precisions have been obtained and it has been possible to consider the incorporation of this technology for monitoring structures deformations. Among TLS applications it have to be emphasized those of registry of the cultural heritage, stages registry during construction of industrial plants and structures, police statement of accidents and monitorization of land movements and structures deformations. Compared with the classical dam monitoring, approach based on the registry of a set of points, the fact having a continuous model of the downstream face allows the possibility of introducing deformation analysis methods and behavior models that would improve the understanding and forecast of dam movements. However, the application of TLS technology for dam monitoring must be considered like a complementary method with the existing ones. Pendulums and recently the differential global positioning system (DGPS) give a continuous information of the movements of certain points of the dam, whereas TLS allows following its seasonal evolution and to detect damaged zones of the dam. A review of the TLS technology characteristics and the factors affecting the final precision of the scanning data is done. It is stated the need of selecting TLS based on the direct time of flight method, also called pulsed, for scanning distances between 100m and 300m. Modelling of structures and vertical walls is studied. Factors that influence in the final precision, like the registry of point clouds, target types, and the combined effect of scanning distance and angle of incidence are analyzed. Finally, a comparison among the movements given by the direct pendulums of a dam and the ones obtained from the analysis of point clouds is done. A new approach to obtain a complete map-type plot of the precisions of TLS equipment based on the direct measurement of time of flight method at midrange distances is presented. Test were developed in field-like conditions, similar to dam monitoring and other civil engineering works. Taking advantage of graphic semiological techniques, a “distance - angle of incidence” map based was designed and evaluated for field-like conditions. A map-type plot was designed combining isolines with sized and grey scale points, proportional to the precision values they represent. Precisions under different field conditions were compared with specifications. For this purpose, point clouds were evaluated under two approaches: the standar "plane-of-best-fit" and the proposed "simulated deformation”, that showed improved performance. These results lead to a discussion and recommendations about optimal TLS operation in civil engineering works. Finally, results of the comparison of seasonal movements of an arc-gravity dam between the registered by the direct pendulums ant the obtained from the TLS scans, are shown. The results show differences of millimeters, being the best around one millimeter. The used methodology is explained and considerations with respect to the point cloud density and to the size of triangular meshes are done.

Low-Intensity Pulsed Ultrasound Improves the Functional Properties of Cardiac Mesoangioblasts

Cell-based therapy is a promising approach for many diseases, including ischemic heart disease. Cardiac mesoangioblasts are committed vessel-associated progenitors that can restore to a significant, although partial, extent, heart structure and function in a murine model of myocardial infarction. Low-intensity pulsed ultrasound (LIPUS) is a noninvasive form of mechanical energy that can be delivered into biological tissues as acoustic pressure waves, and is widely used for clinical applications including bone fracture healing. We hypothesized that the positive effects of LIPUS on bone and soft tissue, such as increased cell differentiation and cytoskeleton reorganization, could be applied to increase the therapeutic potential of mesoangioblasts for heart repair. In this work, we show that LIPUS stimulation of cardiac mesoangioblasts isolated from mouse and human heart results in significant cellular modifications that provide beneficial effects to the cells, including increased malleability and improved motility. Additionally, LIPUS stimulation increased the number of binucleated cells and induced cardiac differentiation to an extent comparable with 5´-azacytidine treatment. Mechanistically, LIPUS stimulation activated the BMP-Smad signalling pathway and increased the expression of myosin light chain-2 together with upregulation of β1 integrin and RhoA, highlighting a potentially important role for cytoskeleton reorganization. Taken together, these results provide functional evidence that LIPUS might be a useful tool to explore in the field of heart cell therapy

Tolerance of Arc repressor to multiple-alanine substitutions

Arc repressor mutants containing from three to 15 multiple-alanine substitutions have spectral properties expected for native Arc proteins, form heterodimers with wild-type Arc, denature cooperatively with Tms equal to or greater than wild type, and, in some cases, fold as much as 30-fold faster and unfold as much as 50-fold slower than wild type. Two of the mutants, containing a total of 14 different substitutions, also footprint operator DNA in vitro. The stability of some of the proteins with multiple-alanine mutations is significantly greater than that predicted from the sum of the single substitutions, suggesting that a subset of the wild-type residues in Arc may interact in an unfavorable fashion. Overall, these results show that almost half of the residues in Arc can be replaced by alanine en masse without compromising the ability of this small, homodimeric protein to fold into a stable, native-like structure.

Dual regulation of open-complex formation and promoter clearance by Arc explains a novel repressor to activator switch.

In studies of variants of the P(ant) promoter of bacteriophage P22, the Arc protein was found not only to slow the rate at which RNA polymerase forms open complexes but also to accelerate the rate at which the enzyme clears the promoter. These dual activities permit Arc, bound at a single operator subsite, to act as an activator or as a repressor of different promoter variants. For example, Arc activates a P(ant) variant for which promoter clearance is rate limiting in the presence and absence of Arc but represses a closely related variant for which open-complex formation becomes rate limiting in the presence of Arc. The acceleration of promoter clearance by Arc requires occupancy of the operator subsite proximal to the -35 region and is diminished when Arc bears a mutation in Arg-23, a residue that makes a DNA-backbone contact in the operator complex.

Toward a mechanism for GroEL.GroES chaperone activity: an ATPase-gated and -pulsed folding and annealing cage.

Free GroEL binds denatured proteins very tightly: it retards the folding of barnase 400-fold and catalyzes unfolding fluctuations in native barnase and its folding intermediate. GroEL undergoes an allosteric transition from its tight-binding T-state to a weaker binding R-state on the cooperative binding of nucleotides (ATP/ADP) and GroES. The preformed GroEL.GroES.nucleotide complex retards the folding of barnase by only a factor of 4, and the folding rate is much higher than the ATPase activity that releases GroES from the complex. Binding of GroES and nucleotides to a preformed GroEL.denatured-barnase complex forms an intermediately fast-folding complex. We propose the following mechanism for the molecular chaperone. Denatured proteins bind to the resting GroEL.GroES.nucleotide complex. Fast-folding proteins are ejected as native structures before ATP hydrolysis. Slow-folding proteins enter chaperoning cycles of annealing and folding after the initial ATP hydrolysis. This step causes transient release of GroES and formation of the GroEL.denatured-protein complexes with higher annealing potential. The intermediately fast-folding complex is formed on subsequent rebinding of GroES. The ATPase activity of GroEL.GroES is thus the gatekeeper that selects for initial entry of slow-folding proteins to the chaperone action and then pumps successive transitions from the faster-folding R-states to the tighter-binding/stronger annealing T-states. The molecular chaperone acts as a combination of folding cage and an annealing machine.

Induction of antigen-specific cytolytic T cells in situ in human melanoma by immunization with synthetic peptide-pulsed autologous antigen presenting cells.

Human melanoma cells can process the MAGE-1 gene product and present the processed nonapeptide EADPTGHSY on their major histocompatibility complex class I molecules, HLA-A1, as a determinant for cytolytic T lymphocytes (CTLs). Considering that autologous antigen presenting cells (APCs) pulsed with the synthetic nonapeptide might, therefore, be immunogenic, melanoma patients whose tumor cells express the MAGE-1 gene and who are HLA-A1+ were immunized with a vaccine made of cultured autologous APCs pulsed with the synthetic nonapeptide. Analyses of the nature of the in vivo host immune response to the vaccine revealed that the peptide-pulsed APCs are capable of inducing autologous melanoma-reactive and the nonapeptide-specific CTLs in situ at the immunization site and at distant metastatic disease sites.

Kinetics of hydrogen bond breakage in the process of unfolding of ribonuclease A measured by pulsed hydrogen exchange.

A sensitive test for kinetic unfolding intermediates in ribonuclease A (EC 3.1.27.5) is performed under conditions where the enzyme unfolds slowly (10 degrees C, pH 8.0, 4.5 M guanidinium chloride). Exchange of peptide NH protons (2H-1H) is used to monitor structural opening of individual hydrogen bonds during unfolding, and kinetic models are developed for hydrogen exchange during the process of protein unfolding. The analysis indicates that the kinetic process of unfolding can be monitored by EX1 exchange (limited by the rate of opening) for ribonuclease A in these conditions. Of the 49 protons whose unfolding/exchange kinetics was measured, 47 have known hydrogen bond acceptor groups. To test whether exchange during unfolding follows the EX2 (base-catalyzed) or the EX1 (uncatalyzed) mechanism, unfolding/exchange was measured both at pH 8.0 and at pH 9.0. A few faster-exchanging protons were found that undergo exchange by both EX1 and EX2 processes, but the 43 slower-exchanging protons at pH 8 undergo exchange only by the EX1 mechanism, and they have closely similar rates. Thus, it is likely that all 49 protons undergo EX1 exchange at the same rate. The results indicate that a single rate-limiting step in unfolding breaks the entire network of peptide hydrogen bonds and causes the overall unfolding of ribonuclease A. The additional exchange observed for some protons that follows the EX2 mechanism probably results from equilibrium unfolding intermediates and will be discussed elsewhere.

Nagorno-Karabakh and the arc of crises on Europe's borders. EPC Policy Brief, 3 February 2016

For more than two decades, Azerbaijan and Armenia have been locked in a stalemate over the Nagorno-Karabakh. The protracted conflict remains the biggest impediment to security, stability and prosperity in the South Caucasus. The EU has put itself on the sidelines of the conflict resolution process, allowing the Organization for Security and Co-operation in Europe (OSCE) Minsk Group (MG), of which Russia, France and the US are co-chairs, to take centre stage. In this Policy Brief, Amanda Paul and Dennis Sammut argue that the EU should play a more active role in the conflict resolution process, taking the lead with innovative initiatives and using its soft power skills and experience. A recent review of the European Neighbourhood Policy recognises that protracted conflicts continue to hamper development in the region. This new approach now needs to be given substance, before the conflict further escalates and becomes another crisis on Europe’s border the already burdened Union cannot cope with.