Dissertations / Theses on the topic 'Ground characterization'

The optical turbulence, which creates perturbations of the wavefronts coming from the stars, is caused by small-scale fluctuations in the index of refraction of the atmosphere and is a problem for astronomers because it limits the maximum resolution of the ground-based telescopes. One way of identifying the best sites to build astronomical observatories, where the influence of the optical turbulence is as small as possible, is to use the standard meteorological parameters to get a first idea of the potential of a site. In the first part of this thesis the three sites on the Internal Antarctic Plateau that are the most interesting for astronomers (Dome A, Dome C and the South Pole) are investigated using the operational analyses of the ECMWF and a ranking of these three sites is presented. The second part of this thesis focuses on the ability of the mesoscale model Meso-NH to simulate the optical turbulence as well as the wind speed at Mt Graham (AZ, USA). A rich sample of measurements of the vertical distribution of the optical turbulence, the largest sample used in this type of study so far, is used to calibrate the Meso-NH model and to quantify its ability to simulate the optical turbulence. The measurements are distributed over different periods of the year thus making it possible to evaluate the performance of the model in different seasons. Both the vertical distribution of the optical turbulence and the astroclimatic parameters (seeing, wavefront coherence time and isoplanatic angle) are investigated.
Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 708

The goal of the present study is to characterize the ground chip and ground pellet particles with respect to their size, shape, density, flow properties, drying and pyrolysis mass loss. Commercial wood pellets and pulp-quality wood chips are used in this study. These commercial samples are ground in the laboratory using a range of grinder screen sizes. The grinder power input is measured. The ground particles are examined for their size and shape. The ground particles are thermally treated in a micro TGA equipment and in a lab-scale thin-layer drying/pyrolysis equipment. The grinding results show that grinding a whole pellet to the desirable particle sizes for pyrolysis (~1 mm) takes around 1/7 of energy required to grind a whole wood chip to the same mean particle size. Pellet particles are denser, more spherical and shorter than the needle-shape chip particles. The spheroid shape of ground pellet particles lowers the compressibility of bulk, lowers the cohesion among the particles and facilitates their flowability. Higher density and random fiber orientation of the pellet particles prolong the duration of their drying significantly compared to the drying time of thin and long wood chip particles. Further moisture diffusion modeling shows that the moisture diffusion rate inside the pellet particles is half of those inside the chip particles. Although chip and pellet particles show the same level of shrinkage in size of a single particle due to drying, ground pellet particles exhibit a larger reduction in their bed porosity than the bed porosity measured for ground chip particles. Both chip and pellet particles reach their fiber saturation point at a moisture content of around 0.50 (dry basis). The pyrolysis kinetic parameters are determined experimentally and a two-zone kinetic mechanism is modeled and validated using the experimental thin-layer pyrolysis data.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

La thèse présente les résultats expérimentaux obtenus au cours du développement et des essais au sol du modèle de vol de l'horloge à atomes froids PHARAO. PHARAO est le premier étalon primaire de fréquence dédié à des applications spatiales. Il est développé par l'agence spatiale française CNES. PHARAO est un des principaux instruments de la mission spatiale de l'ESA: ACES (Atomic Clock Ensemble in Space). Le lancement est prévu en 2016. La mission est basée sur des comparaisons de très hautes performances en temps et en fréquence, entre PHARAO et un ensemble d’horloges basées au sol, pour effectuer des tests en physique fondamentale. La charge utile sera installée sur une palette extérieure de la Station spatiale internationale. Après une introduction sur les horloges atomiques et un résumé de la mission ACES, l'architecture de PHARAO optimisée pour la microgravité et son fonctionnement sont décrits. Ensuite nous présentons les mesures et l'analyse de la stabilité de fréquence. Au sol la stabilité de fréquence est mesurée à un niveau de 3,1x10-13 t-1/2. Cette valeur est en accord avec les différentes sources de bruit. En microgravité la stabilité atteindra 10-13 t-1/2. Pour terminer les principaux déplacements de fréquence sont analysés. Une étude détaillée est donnée sur les propriétés des blindages magnétiques, leurs hystérésis et la conception d’une compensation magnétique active. L'objectif est de réduire l'incertitude sur l’effet Zeeman du second ordre au niveau de quelques 10-17. La détermination de la température de l’environnement des atomes est également analysée avec l'objectif d'atteindre une incertitude sur le déplacement de fréquence par le rayonnement du corps noir dans la gamme de 10-17. Un budget préliminaire sur l’incertitude de fréquence de l’horloge au sol s’établit à 1,1x 10-15. Ce budget est compatible avec un objectif de 3x10-16 en microgravité. La prochaine étape verra l’assemblage tous les autres instruments ACES pour un lancement prévu en 2016
This thesis presents the experimental results obtained during the development and the ground tests of the flight model of the cold atoms space clock PHARAO. PHARAO, the first Primary Frequency Standard (PFS) for space applications, is developed by the French space agency CNES. It is a main instrument of the ESA space mission ACES: Atomic Clock Ensemble in Space with a launch scheduled on 2016. The mission is based on high performances time and frequency comparisons between a payload including PHARAO and ground based clocks to perform tests in fundamental physics. The payload will be installed on an external pallet of the International Space Station. After an introduction on atomic clocks and a summary on the ACES mission, the PHARAO architecture, optimized for microgravity environment, and its operation is described. It is followed by the measurements and the analysis of the frequency stability. On ground the frequency stability is measured at a level of 3.1 10-13 t-1/2. This value is in agreement with the different sources of noise. In space the frequency stability will reach 10-13 t-1/2. Finally the main frequency shifts are analyzed. A detailed study is given on magnetic shield properties, hysteresis and the design of the active magnetic compensation. The objective is to reduce the uncertainty of the second order Zeeman effect within few 10-17. The temperature determination of the atomic environment is also detailed and the goal is to reach an uncertainty on the blackbody frequency shift in the 10-17 range. A preliminary budget on the frequency accuracy of PHARAO on ground is evaluated at 1.1 10-15. This value is compatible with the expected accuracy budget of 3x10-16 when the clock will operate in microgravity. In the next step all the ACES instruments will be assembled for a launch scheduled on 2016

Ground penetrating radar (GPR) has been used as a railway substructure investigation tool since the late 1990’s and has seen significant development since then. To use GPR as a more effective tool for substructure investigation, a GPR substructure characterization model was developed. This dissertation provides a detailed description of railway track components, track geometry, soil properties and classification and substructure design. The historical background of GPR is discussed together with GPR principles, basic GPR equations, hardware and accessories as well as GPR data collection, processing and interpretation. Other in situ investigation techniques namely the dynamic cone penetrometer (DCP), light weight deflectometer (LWD) , Pencel pressuremeter, surface wave testing, remote video monitoring (RVM), multi-depth deflectometers (MDD) and continuous track modulus measurement techniques are also discussed. A comparison between the different track investigation techniques was also done, with reference to sample rate, cost, effectiveness and value. Two sites in South Africa were selected for the investigation, one with good substructure conditions used for heavy haul coal export close to Vryheid (KN test section) and the other a general freight line with poor substructure conditions near Rustenburg (NT test section). These two sites were selected to develop a GPR substructure characterization model as they provided conditions ranging from poor to very good. This was supported by the analysis of the in situ soil sampling and testing. The calculation of the track substructure modulus from RVM deflection measurements showed three times higher values for the KN test section compared to the NT test section. The subballast and subgrade thickness, the GPR ballast fouling (GBF) index as well as the GPR moisture condition index was used for the classification ranges used in the model. The subballast and subgrade layer roughness values were calculated and used for the substructure classification. The GBF index and the GPR moisture condition roughness were used for the GPR fouling index classification. The GPR deliverables were divided into four classes (i.e. very good, good, moderate and poor). The evaluation of the characterization model showed that a traditional in situ investigation will cost approximately 3.7 times more than that of a GPR investigation. It would also take two thirds of the time to complete the GPR investigation compared to the traditional in situ investigation. The study showed that GPR can be used to develop a substructure characterization model and that it would be more cost effective and efficient than traditional in situ investigation techniques. GPR surveys provide continuous measurements of the track structure condition and can therefore provide a continuous classification unlike the discreet and fragmented nature of in situ investigations. However, in situ tests can be done at certain intervals within the GPR survey or at point where the GPR classification is not clear. The best solution for railway track characterization can therefore be obtained by using GPR and in situ classification in combination.
Dissertation (MEng)--University of Pretoria, 2012.
Civil Engineering
unrestricted

Thesis (M.S. in Aeronautical Engineering)--Naval Postgraduate School, June 1990.
Thesis Advisor(s): Wu, Edward M. Second Reader: Schmidt, Louis V. "June 1990." Description based on title screen as viewed on March 22, 2010. DTIC Identifier(s): Flight Envelope, External Stores, Aerodynamics Stability, Theses, Sidewinder Missiles, P-3 Aircraft, Antisubmarine Aircraft. Author(s) subject terms: Flutter, P-3, Ground Vibration Tests, Flutter Modeling, Modal Modeling. Includes bibliographical references (p. 68). Also available in print.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1999.
Includes bibliographical references (leaves 232-236).
Ground penetrating radar (GPR) surveys are performed to determine geologic structure and to assist in the characterization and eventual modeling of ground water flow beneath the Well-H region of the Aberjona River in Woburn, Massachusetts. Even though cone penetrometer and coring studies provide point source "ground truth" data about the stratigraphy, soil chemistry, and composition of the first seven meters of peat, sand and silt they are time-consuming and labor intensive. The advantage of GPR is its ability to extend point-source ground truth information into two and three dimensions. This dissertation provides an accurate geologic model of one section of the Aberjona wetland by improving the state of three-dimensional GPR imaging. Data fusion, target implantation, and a novel 3-D migration technique are combined to render the subsurface volume accurately to resolutions of about 30 centimeters in all directions. The technique was tested using various synthetically generated models as well as carefully constructed test pits to verify its accuracy and estimate error. For our surveys in the wetland, we verify the accuracy of our method using the large database of "ground truth" information about subsurface structure and soil properties. We use this information along with data collected for this project to assemble what 3-D geological information we can. For example, direct measurements of soil bulk properties are made at various depths in several locations. Borehole conductivity surveys not only confirm core sample measurements, but also give deep conductivity information not otherwise available. Cone penetrometer surveys provide high vertical resolution to map stratigraphic variation. A 3-D resistivity survey provides general information about the conductivity of the site. In addition to ground truth measurements, several different types of radar surveys were employed to estimate soil electrical properties. A new method of Vertical Radar Profiling (VRP) was developed to provide velocity information at different locations and various depths throughout the wetland. Morphing methods were applied as an interpolation tool for surveys with broadly spaced profiles. A fast three dimensional migration algorithm was developed specifically for GPR imaging that incorporates layered velocity information and soil electrical conductivity. Ultimately, this technique is shown to offer a means of mapping larger regions of wetland stratigraphy more accurately than was currently feasible.
by David Bishop Cist.
Ph.D.

The objective of this thesis was to gain a better understanding of the physical process of ground improvement by vibro-replacement and of how the induced changes in ground conditions affect the interpretation of seismic cone penetration testing used to assess its effectiveness. This was achieved by a combination of field testing and monitoring supported by numerical modelling of both the vibro-replacement process and of in situ testing. Field measurements were made of the input motions created by the vibrator and the induced response of the ground. The measured vibrator motions were input to a numerical model of the soil mass and the results of the analysis were compared to the measured data. The results of seismic cone testing before and after treatment at 15 sites and existing chamber test data were analyzed and additional numerical modelling of seismic cone testing in the post-treatment ground conditions was carried out. The study showed that the ground response to the vibrator attenuated with distance due to geometrical spreading and material damping. The direction of the principal horizontal acceleration changed with distance from the vibrator. It was shown that vibro-replacement creates a young, heterogeneous deposit comprising the native soil with increases in density and horizontal stress varying with distance from stiffer stone columns. If the induced heterogeneity is neglected when interpreting in situ test results, there will be some over-estimation of the soil properties close to the cone hole and considerable under-estimation of the average properties of the composite mass. The stiffer stone columns also change the wave propagation regime during down-hole testing and prevent reliable interpretation of the shear wave velocity o f the improved native soil. Analysis of field test data showed that vibro-replacement causes an apparent shift in soil behaviour type classification. The combined effects of changes in density, horizontal stress and time dependent soil stiffness were shown to be important when interpreting seismic cone results. Friction ratio was found not diagnostic of changes in soil conditions. For the soils studied, a correlation was derived between achievable tip resistance and pre-treatment soil behaviour type for several stone column spacings.
Applied Science, Faculty of
Civil Engineering, Department of
Graduate

Carbon-14 was measured in the dissolved organic carbon (DOC) in ground water and compared with ¹⁴C analyses of dissolved inorganic carbon (DIC). Two field sites were used for this study; the Stripa mine in central Sweden, and the Milk River Aquifer in southern Alberta, Canada. The Stripa mine consists of a Precambrian granite dominated by fracture flow, while the Milk River Aquifer is a Cretaceous sandstone aquifer characterized by porous flow. At both field sites, ¹⁴C analyses of the DOC provide additional information on the ground-water age. At the Stripa site the DIC from the recharge area probably precipitates at around the 300 m level of the mine, never reaching the deeper ground waters. In this case, ¹⁴C analyses of the DOC provides a better estimate of the ground-water age. The dilution of the DIC by carbonates and microbial processes in the Milk River Aquifer is so great that geochemical corrections of ¹⁴C data are difficult. This is another example where ¹⁴C analyses of the DOC provide more information on ground-water age. Carbon-14 was measured on both the hydrophobic and hydrophilic organic fractions of the DOC. At the Stripa site, the hydrophobic organic compounds in the V2 borehole ranged from 7,500 to 15,500 years before present, suggesting a young component of ground water. Other hydraulic and isotopic evidence supports relatively recent ground water mixing with older brines in this borehole. The δ¹³C values of the DIC in the V2 borehole are light and similar to the stable carbon isotope values for the DOC, supporting a biogenic origin of the DIC. The organic compounds in the hydrophobic and hydrophilic fractions were also characterized. The DOC may originate from kerogen in the aquifer matrix, from soil organic matter in the recharge zone, or from a combination of these two sources. Carbon-14 analyses, along with characterization of the organics, were used to determine this origin. Carbon-14 analyses of the hydrophobic fraction in the Milk River Aquifer suggest a soil origin, while ¹⁴C analyses of the hydrophilic fraction suggest an origin within the Cretaceous sediments (kerogen) or from the shale in contact with the aquifer.

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
O método GPR Ground Penetrating Radar foi empregado nesta pesquisa visando estimar suas potencialidades como uma metodologia viável para os estudos geológicos, geotécnicos e ambientais em condições brasileiras.Para o alcance deste objetivo foram realizados ensaios em campo procurando avaliar a capacidade deste método na detecção das alterações provenientes da ação intempérica na formação do solo residual, ou seja, estimar a profundidade e espessura dos horizontes pedológicos, e o topo rochoso em um perfil geotécnio. Foram também realizados ensaios em laboratório onde fez-se o monitoramento do efeito da contaminação por hidrocarbonetos em blocos indeformados de solo residual, tanto em condições não saturadas, quanto na zona de saturação, procurando avaliar a aplicabilidade do método GPR na detecção deste tipo de contaminante.Os resultados obtidos permitiram imagear com boa resolução os contrastes bruscos, como o topo da rocha sã e blocos inclusos no solo, mas não a detecção nítida dos horizontes no perfil; e pela análise do monitoramento da contaminação, ainda é recente afirmar que o método GPR possa ser empregado com grande eficiência na detecção de contaminantes orgânicos em solo residual.
The GPR method Ground Penetration Radar was used in this work, aiming at estimating its potentialities as a viable methodology to geological, geotechnical and environmental studies of Brazilian soil-rock conditions.In order to reach this objective, in situ tests have been carried out to evaluate the capability of the method in the detection of characteristics of weathering profiles in residual soils. In this case, the aim was to estimate the depth and width of pedological horizons and the bedrock in a geotechnical profile. Laboratory tests were also carried out in blocks of undisturbed residual soil of gnaissic origin. In these blocks, the effects of contamination by petroleum hydrocarbons were monitored. Both the unsaturated and the vadose zones have been monitored. The main objective in relation to the GPR was to evaluate the applicability of the method in the detection of such contaminants.The results obtained allowed to image gross contacts with good resolution such as soil-intact bedrock contacts and blocks inside soils. However, the clear detection of profile horizons were not well imaged. Regarding the contamination monitoring, it is early to affirm that the GPR method might be employed efficiently in the detection of organic contaminants in residual soils.

This thesis focuses on traction control techniques for electric vehicles with independently driven wheels . The aim is to maximise the grip of each wheel with the ground, improving the performance as well as the stability of the whole vehicle. Hence the estimation of the friction characteristic between tyres and ground is addressed . Accurate estimat ion is required not only to control the wheels at their best working condition but also to predict their behaviour for future manoeuvres. This information could be used to calculate the braking distance or to evaluate the maximum attainable speed during cornering . A detailed knowledge of the friction characteristic would substantially improve the functionality of anti-lock braking system (ABS), anti-slip regulation (ASR), electronic stability control (ESC) and adaptive cruise control (ACC) . Estimation of ground characteristics and traction control for electric vehi­cles have been studied before, although previous research generally relies on driving manoeuvres at the limit of adhesion to obtain meaningful information about the maximum grip offered by the ground. This is not suitable during safe driving on public roads and the present thesis addresses the problem of constantly monitoring the road conditions, and forecasting the loss of adhesion instead of waiting for it . Furthermore, my approach is robust against external forces and can be applied to vehicles on tilted grounds. Hence my novel approach supersedes previous studies that assumed the vehicle on a flat surface, mostly neglecting the effects of rolling resistance and aerodynamic drag. I also propose a framework to take into cons.ideration dynamic effects such as iner­ tial forces and the distribution of the gravitational force. Taking these effects into account would lead to a more reliable estimation, particularly effective on steep or bumpy roads where adhesion loss is more likely to happen . Some of this work resulted in the publication of an IEEE conference paper . My work belongs to a larger project aiming to develop an autonomous elec­tric vehicle whose main targets are economic and environmental sustainability. These targets led us to consider moving some of the computational require­ ments for the automatic guidance to a remote serve, wirelessly communicating with the vehicle. Together with this investigation1 original contributions of the project will include scene understanding solely based on stereo cameras and integration between the visual information and the vehicle dynamic response captured by the vehicle controller . My research is focused on this application, and a considerable amount of energy through my PhD went to the develop­ment of the system required to remotely control the vehicle. An extensive description of the development phase is included in this thesis.

The sustained yield of a well field adjacent to Lower Lake Mary reservoir, south of Flagstaff, Arizona, has been calculated in two separate studies, and the results differ significantly. One reason for the difference is the lack of understanding of the effect that the reservoir has on recharge to the well field. Samples were taken from various surface waters, springs, and production wells in the area surrounding Flagstaff to chemically characterize the waters and to examine the potential recharge source(s) to the Lake Mary well field. Results indicate that nearly all ground waters in the area are calcium-magnesium-bicarbonate in composition, but they differ significantly in total hardness. Isotopic values of the samples indicate that only one well within the Lake Mary well field is definitely receiving significant recharge from the reservoir.

The objective of quantitative Performance-Based Earthquake Engineering (PBEE) is designing buildings that meet the specified performance objectives when subjected to an earthquake. One challenge to completely relying upon a PBEE approach in design practice is the open-ended nature of characterizing the earthquake ground motion by selecting appropriate ground motions and Intensity Measures (IM) for seismic analysis. This open-ended nature changes the quantified building performance depending upon the ground motions and IMs selected. So, improper ground motion and IM selection can lead to errors in structural performance prediction and thus to poor designs. Hence, the goal of this dissertation is to propose methods and tools that enable an informed selection of earthquake IMs and ground motions, with the broader goal of contributing toward a robust PBEE analysis. In doing so, the change of perspective and the mechanism to incorporate additional information provided by Bayesian methods will be utilized. Evaluation of the ability of IMs towards predicting the response of a building with precision and accuracy for a future, unknown earthquake is a fundamental problem in PBEE analysis. Whereas current methods for IM quality assessment are subjective and have multiple criteria (hence making IM selection challenging), a unified method is proposed that enables rating the numerous IMs. This is done by proposing the first quantitative metric for assessing IM accuracy in predicting the building response to a future earthquake, and then by investigating the relationship between precision and accuracy. This unified metric is further expected to provide a pathway toward improving PBEE analysis by allowing the consideration of multiple IMs. Similar to IM selection, ground motion selection is important for PBEE analysis. Consensus on the "right" input motions for conducting seismic response analyses is often varied and dependent on the analyst. Hence, a general and flexible tool is proposed to aid ground motion selection. General here means the tool encompasses several structural types by considering their sensitivities to different ground motion characteristics. Flexible here means the tool can consider additional information about the earthquake process when available with the analyst. Additionally, in support of this ground motion selection tool, a simplified method for seismic hazard analysis for a vector of IMs is developed. This dissertation addresses four critical issues in IM and ground motion selection for PBEE by proposing: (1) a simplified method for performing vector hazard analysis given multiple IMs; (2) a Bayesian framework to aid ground motion selection which is flexible and general to incorporate preferences of the analyst; (3) a unified metric to aid IM quality assessment for seismic fragility and demand hazard assessment; (4) Bayesian models for capturing heteroscedasticity (non-constant standard deviation) in seismic response analyses which may further influence IM selection.
Doctor of Philosophy
Earthquake ground shaking is a complex phenomenon since there is no unique way to assess its strength. Yet, the strength of ground motion (shaking) becomes an integral part for predicting the future earthquake performance of buildings using the Performance-Based Earthquake Engineering (PBEE) framework. The PBEE framework predicts building performance in terms of expected financial losses, possible downtime, the potential of the building to collapse under a future earthquake. Much prior research has shown that the predictions made by the PBEE framework are heavily dependent upon how the strength of a future earthquake ground motion is characterized. This dependency leads to uncertainty in the predicted building performance and hence its seismic design. The goal of this dissertation therefore is to employ Bayesian reasoning, which takes into account the alternative explanations or perspectives of a research problem, and propose robust quantitative methods that aid IM selection and ground motion selection in PBEE The fact that the local intensity of an earthquake can be characterized in multiple ways using Intensity Measures (IM; e.g., peak ground acceleration) is problematic for PBEE because it leads to different PBEE results for different choices of the IM. While formal procedures for selecting an optimal IM exist, they may be considered as being subjective and have multiple criteria making their use difficult and inconclusive. Bayes rule provides a mechanism called change of perspective using which a problem that is difficult to solve from one perspective could be tackled from a different perspective. This change of perspective mechanism is used to propose a quantitative, unified metric for rating alternative IMs. The immediate application of this metric is aiding the selection of the best IM that would predict the building earthquake performance with least bias. Structural analysis for performance assessment in PBEE is conducted by selecting ground motions which match a target response spectrum (a representation of future ground motions). The definition of a target response spectrum lacks general consensus and is dependent on the analysts’ preferences. To encompass all these preferences and requirements of analysts, a Bayesian target response spectrum which is general and flexible is proposed. While the generality of this Bayesian target response spectrum allow analysts select those ground motions to which their structures are the most sensitive, its flexibility permits the incorporation of additional information (preferences) into the target response spectrum development. This dissertation addresses four critical questions in PBEE: (1) how can we best define ground motion at a site?; (2) if ground motion can only be defined by multiple metrics, how can we easily derive the probability of such shaking at a site?; (3) how do we use these multiple metrics to select a set of ground motion records that best capture the site’s unique seismicity; (4) when those records are used to analyze the response of a structure, how can we be sure that a standard linear regression technique accurately captures the uncertainty in structural response at low and high levels of shaking?

Asphalt binder modification is a common method of improving Hot-mix Asphalt (HMA) performance by enhancing mix properties and reducing or delaying three general HMA distress types: deformation (rutting and shoving), cracking (from repeated loads and low temperatures) and general deterioration (raveling and stripping).

Since the early 1960’s, a common modified asphalt alternative has employed reclaimed rubber as an economical and environmental friendly method of recycling waste tires while improving asphalt physical and mechanical properties. Pavement network deterioration combined with increasing material costs makes polymer modification of asphalt binder desirable, with reclaimed rubber from waste tires being an attractive alternative which addresses performance, economics and environmental issues.

The primary objective of this dissertation is to demonstrate the importance of proper processing of all types of modified bituminous binders, whether they be virgin (e.g. styrene-butadiene-styrene (SBS) or styrene-butadiene rubber (SBR)), post-consumer polymers (e.g. ground tire rubber (GTR)) or a combination (GTR plus SBS). To achieve this four secondary objectives were identified: 1) characterize GTR using thermo-gravimetric analysis (TGA), 2) improve processing of GTR modified binders, 3) improve testing and specifications of GTR modified binders and 4) evaluate mixes containing GTR modified binders.

A simple efficient instrumental, TGA, method to analyze polymers in binary rubber compounds was developed to quantify the functional polymer content available in GTR. TGA analysis provides a better understanding of the general chemical characteristics of GTR used in modification of asphalt binders for production of asphalt paving mixtures.

Results are presented from efforts to optimize GTR modified binder formulations with respect to how GTR loading, GTR particle size, processing temperature and asphalt cement source affect modified binder properties and ability to meet performance graded binder specifications. These results are the basis to establish recommended processing parameters for formulation and preparation of GTR modified asphalt binders.

GTR modified binders were used in: dense graded asphalt (DGA), stone matrix asphalt (SMA) and open graded friction courses (OGFC) and compared to conventional asphalt cement and styrene-butadiene-styrene (SBS) modified asphalt binders. Mixture performance evaluation with respect to binder effectiveness as it relates to the three general HMA distress types.

Temporally and spatially clustered earthquake sequences along plate boundary zones indicate that patterns of seismicity may be influenced by earthquake-induced stress changes. Many studies invoke Coulomb stress change (CSC) as one possible geo-mechanical mechanism to explain stress interactions between earthquakes, their aftershocks, or large subsequent earthquakes; however, few address the statistical robustness of CSC triggering beyond spatial correlations. To address this, I evaluate the accuracy of CSC predictions in subduction zones where Earth’s largest earthquakes occur and generate voluminous and diverse aftershock sequences. A series of synthetic tests are implemented to investigate the accuracy of inferred stress changes predicted by slip distributions inverted from suites of geodetic observations (InSAR, GPS, seafloor geodetic observations) that are increasingly available for subduction zone earthquakes. Through these tests, I determine that inferred stress changes are accurately predicted at distances greater than a critical distance from modeled slip that is most dependent on earthquake magnitude and the proximity of observations to the earthquake itself. This methodology is then applied to the 2010 Mw 8.8 Maule, Chile earthquake sequence to identify aftershocks that may be used to perform statistically robust tests of CSC triggering; however, only 13 aftershocks from a population of 475 events occurred where confidence in CSC predictions is deemed to be high. The inferred CSC for these events exhibit large uncertainties owing to nodal plane uncertainties assigned to the aftershock mechanisms. Additionally, tests of multiple published slip distributions result in inconsistent stress change predictions resolved for the 13 candidate aftershocks. While these results suggest that CSC imparted by subduction megathrust earthquakes largely cannot be resolved with slip distributions inverted from terrestrial geodetic observations alone, the synthetic tests suggest that dramatic improvements can be made through the inclusion of near-source geodetic observations from seafloor geodetic networks. Furthermore, CSC uncertainties will likely improve with detailed earthquake moment tensor catalogs generated from dense regional seismic networks.

Thesis (S.M. in Geosystems)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2003.
Includes bibliographical references (p. 103-105).
Ground penetrating radar (GPR) surveys are performed to determine the depth to the water table and the tops of wood piles beneath a residential structure at 122 Beacon Street in Back Bay, Boston. The area of Boston known as the Back Bay was once a tidal estuary of the Charles River. During the latter half of the 19th century, the Back Bay was filled to create room for the city's expanding population. Most of the structures built in the Back Bay during this period were residential buildings supported by untreated wood pile foundations. Submerged beneath the water table, untreated wood piles maintain their structural integrity indefinitely. However, recent groundwater fluctuations throughout the Back Bay have exposed the tops of some of the piles, causing the exposed areas to rot. Rotted wood piles weaken a structure's foundation and often result in differential settlement or cracking in walls or foundations. The current method of investigating suspected pile failure is to excavate a foundation and to physically inspect the piles, noting the elevation of the water table. In many cases, foundations may be stabilized by underpinning: replacing rotted wood piles with steel beams or concrete plugs often at great cost to the owner of the building. The research presented in this thesis investigates the usefulness of GPR in determining the proximity of the tops of wood piles relative to the water table. Two different types of radar surveys were used in an attempt to estimate the depth to the water table and the tops of the piles. Data collected from several radar surveys is interpreted and compared with ground truth derived from historical references, water level data from monitoring wells, observations from recent excavations, and the results of a resistivity survey. The results of this study indicate that modifications of this technique may allow more definite interpretation of wood pile foundations than traditional GPR surveys can provide in this type of environment.
by Suzanne O'Neil LeFrançois.
S.M.in Geosystems

Ce travail porte sur la production et la caractérisation de matériaux composites hybrides basés sur un polymère thermoplastique (polyéthylène de haute densité, PEHD), une fibre naturelle (chanvre) et un caoutchouc recyclé provenant de pneus usés (GTR) comme modificateur d'impact. L'addition d'un agent de couplage (polyéthylène maléaté) est également étudiée. Les échantillons sont mélangés par extrusion à double-vis et fabriqués par un moulage en injection. À partir des échantillons obtenus, une caractérisation morphologique et mécanique complète est effectuée. Les résultats montrent que la bonne dispersion est obtenue en raison des bonnes conditions de mélanges sélectionnées et une bonne adhésion interfaciale entre toutes les phases est atteinte en raison de la présence d'anhydride maléique greffée au polyéthylène (MAPE). Enfin, pour des propriétés mécaniques choisies, des modèles de régression non-linéaire sont proposés pour prédire et contrôler les propriétés finales de ces composés par des comparaisons faites sur la base des propriétés de la matrice seule.
Ce travail porte sur la production et la caractérisation de matériaux composites hybrides basés sur un polymère thermoplastique (polyéthylène de haute densité, PEHD), une fibre naturelle (chanvre) et un caoutchouc recyclé provenant de pneus usés (GTR) comme modificateur d'impact. L'addition d'un agent de couplage (polyéthylène maléaté) est également étudiée. Les échantillons sont mélangés par extrusion à double-vis et fabriqués par un moulage en injection. À partir des échantillons obtenus, une caractérisation morphologique et mécanique complète est effectuée. Les résultats montrent que la bonne dispersion est obtenue en raison des bonnes conditions de mélanges sélectionnées et une bonne adhésion interfaciale entre toutes les phases est atteinte en raison de la présence d'anhydride maléique greffée au polyéthylène (MAPE). Enfin, pour des propriétés mécaniques choisies, des modèles de régression non-linéaire sont proposés pour prédire et contrôler les propriétés finales de ces composés par des comparaisons faites sur la base des propriétés de la matrice seule.
This work aims at the production and characterization of hybrid composites based on a thermoplastic polymer (high density polyethylene, HDPE), a natural fiber (hemp) as reinforcement and ground tire rubber (GTR) as an impact modifier. The addition of a coupling agent (maleated polyethylene) is also investigated. The samples are compounded by twin-screw extrusion and produced by injection molding. From the samples obtained, a complete morphological and mechanical characterization is performed. The results show that good dispersion is obtained due to the selected processing conditions and good interfacial adhesion between all the phases is achieved due to the presence of maleic anhydride grafted polyethylene (MAPE). Finally, for selected mechanical properties, nonlinear regression models are proposed to predict and control the final properties of these compounds and comparisons are made based on the neat matrix properties.
This work aims at the production and characterization of hybrid composites based on a thermoplastic polymer (high density polyethylene, HDPE), a natural fiber (hemp) as reinforcement and ground tire rubber (GTR) as an impact modifier. The addition of a coupling agent (maleated polyethylene) is also investigated. The samples are compounded by twin-screw extrusion and produced by injection molding. From the samples obtained, a complete morphological and mechanical characterization is performed. The results show that good dispersion is obtained due to the selected processing conditions and good interfacial adhesion between all the phases is achieved due to the presence of maleic anhydride grafted polyethylene (MAPE). Finally, for selected mechanical properties, nonlinear regression models are proposed to predict and control the final properties of these compounds and comparisons are made based on the neat matrix properties.

Many problems are involved with intspecting and evaluating the condition of bridges in the United States. Concrete bridge deck inspection and evaluation presents one of the largest problems. The deterioration of these concrete decks progresses more rapidly than any other bridge component, which leads to early concrete deck replacements that must be done before the bridge superstructure needs to be replaced. The primary cause of deterioration in these concrete bridge decks is corrosion-induced concrete cracking, which frequently results in delaminations. Delamination distress increases the life cycle cost of maintaining a concrete bridge deck, particularly when it is not detected early on. Early detection of delamination distress can facilitate economical repair and rehabilitation work, but bridge engineers must recommend deck replacement if repairs are delayed too long or inspection tools cannot detect delaminations early enough. The Federal Highway Administration has responded to the need for a better bridge deck inspection tool by contracting Lawrence Livermore National Laboratory to develop two new prototype ground penetrating radar systems. These two systems generate three-dimensional data that provide a representation of features that lie below the bridge deck surface. Both of these systems produce large amounts of data for an individual bridge deck, which makes automated data processing very desirable. The primary goal of the automated processing is to characterize bridge deck distress represented in the data. This study presents data collected from sample bridge deck sections using one of the prototype systems. It also describes the development and implementation of appropriate methods for automating data processing. The automated data processing is accomplished using image processing and pattern recognition algorithms developed in the study.
Ph. D.

A new spatially telescoping approach was proposed to improve measurement flexibility and account for hydrologic scale in field studies of groundwater-surface water (GW-SW) interaction. We applied this spatially telescoping approach in a study GW-SW interactions along Lucile Creek, Alaska. Catchment-scale data were used to screen areas of potentially significant GW-SW exchange, indicating groundwater contribution from a deeper regional aquifer along the middle to lower reaches of the stream. This initial assessment was tested using reach-scale estimates of groundwater contribution during base flow conditions. The reach-scale measurements indicated a large increase in discharge along the middle reaches of the stream accompanied by a shift in chemical composition towards a regional groundwater end member. Point measurements of vertical water fluxes were used to evaluate spatial and temporal variability of GW-SW exchange within representative reaches. The spatially telescoping approach identified locations of GW-SW exchange and improved interpretation of reach-scale and point-scale measurements.

A series of five east-west and two north-south hydrostratigraphic cross sections were drawn from drillers' logs of water wells within the southern half of Cache Valley, Utah. These cross-sections demonstrate that ground water flow to streams is restricted by a continuous low- II permeability layer, nearly 100-feet thick. This layer was correlated to the lake-bottom deposits of the Bonneville (30,000 -13,000 years ago) and Little Valley (140,000 - 90,000 years ago) cycles of the ancient Lake Bonneville. The most productive aquifers in the valley, collectively termed the principal aquifer , are in the southeast corner , approximately between Smithfield and Hyrum, and between the eastern valley margin and the valley center. Sands and gravels of the principal aquifer were deposited as alluvial fans and deltas by streams draining the Bear River Range. Ground water chemistry in the principal aquifer system is of the calcium-magnesium bicarbonate type with total dissolved solids (TDS) averaging about 300 ± 100 mg/L. TDS and the relative proportions of sodium, potassium, and chloride increase down flowpath, from recharge areas in the east to discharge areas in the west. Oxygen-18 (18O) and deuterium (D) analyses were performed on precipitation samples at three locations on the east valley benches, four surface water samples from streams entering the valley, and fourteen ground water samples from either wells or springs. Precipitation and surface water values generally plotted along the Global Meteoric Water Line (GMWL), although the precipitation values plotted significantly lower on the GMWL than the surface water values. Of the ground water samples, twelve from the principal aquifer generally clustered near the surface water data points, suggesting that water from streams, rather than infiltrating precipitation, recharges the principal aquifer. Twelve ground water samples were analyzed for tritium. The tritium values of eight samples from wells or springs in the principal aquifer suggest recharge after 1952. Two samples with tritium values dating prior to 1952 are from wells in the principal aquifer, and two are from wells west of the principal aquifer. Four samples were analyzed for 14C. Two of these wells were completed in the principal aquifer and two west of it. Correcting for partial carbon dilution, the age difference between the different areas is on the order of tens of thousands of years.

This report is exploring the possibility of characterizing hot Jupiter atmospheres using ground-based high-resolution spectroscopy. The ESO CRIRES infrared spectrometer is selected as the observing tool. Simulated observations are computed for known transiting systems. The properties of observations (noise, spectral coverage, resolution) are estimated with the CRIRES Exposure Time Calculator. An inverse method is used for reconstructing the transmission spectra of exoplanetary atmospheres and identifying spectral features. The possibility of using this method for non-transiting systems is examined. Three exoplanets are deemed possible to reconstruct the spectrum of.
Den här rapporten studerar möjligheten att karaktärisera heta Jupiter atmosfärer genom att använda markbaserad högupplöst spektroskopi. ESO:s CRIRES infraröda spektrometer används som observeringsvektyg. Simulerade observationer beräknas för kända system där planeten genomgår en transit. Flera aspekter kring observationer (brus, våglängdstäckning, upplösning) uppskattas med CRIRES Exposure Time Calculator. En invers metod används för att rekonstruera exoplanetatmosfärers transmissionsspektrum och för att identifiera spektraldrag. Möjligheten att använda den här metoden för system utan transit utforskas. Tre exoplaneter antas vara möjliga att rekonstruera spektrat från.

A novel non-separable non-stationary stochastic model for the representation and simulation of pulse-like earthquake ground motions (PLGMs), capable to accurately represent peak elastic and inelastic structural responses, is proposed in this work. Further, the model is employed for assessing the performance of several time-frequency representation techniques (the harmonic wavelet transform, the Meyer wavelet packets transform, the S-transform and the empirical mode decomposition) in capturing salient features of pulse-like accelerograms. The significantly higher structural demands posed by PLGMs in comparison with similar intensity pulse-free motions led to comprehensive investigations in order to mitigate the damage experienced in the affected areas, such as those located near seismic faults. In this regard, time-frequency analysis methods are frequently employed for the analysis of signals recorded during these events, due to their adaptability to the specific evolutionary behaviour. Alongside with characterization, stochastic modelling of PLGMs is of interest since it allows for systematic variations of the input parameters in order to enhance the understanding of their influence on the structural behaviour. This is particularly useful since only a limited number of PLGMs are available in the existing earthquake databases. Accordingly, inspired by the time-frequency distribution of their total energy, a versatile PLGM model is defined as a combination of amplitude-modulated stochastic processes. Each process models the time-varying distribution of the energy for adjacent frequency ranges. Two alternative formulations are proposed for representing the low-frequency content characterizing the pulses. Considering a set of pulses from the literature, numerical results show that the pulse models‟ parameters can be calibrated to simulate in average the structural impact of these pulses represented using the model herein defined. Further, the capability of the PLGM model to generate elastic and inelastic spectral responses matching a given field recorded accelerogram in the mean sense is illustrated. The applicability of the proposed model to account for near-fault effects to spectrum compatible representations of the seismic action is illustrated by generating a fully stochastic process compatible with the response spectrum of the European aseismic code (EC8). Furthermore, the model can be employed in various applications including generation of accelerograms for nonlinear dynamic analyses of structures, probabilistic seismic demand analyses or as input in stochastic dynamic techniques such as statistical linearization. Finally, the capability of several time-frequency analysis methods to characterize PLGM accelerograms is evaluated through comparative numerical studies within a novel methodology, namely by considering artificial time-histories as samples of the proposed model. The results highlight the potential of the S-transform to be used for pulse identification/extraction and of the harmonic wavelet transform for record characterization/pulse extraction. Additionally, they confirm that from an engineering perspective the structural natural period is an appropriate and representative parameter for the definition of “pulses”. Overall, these analyses shed light into the challenges experienced when attempting to detect the pulse content in the accelerograms, in an effort to inform best practices for PLGMs characterization.

In this work we present the development of observational techniques and data analysis for the follow-up of RV-detected exoplanet candidates and low-mass companions. We observed the exoplanet candidate systems HD 136118 and HD 33636, for which we present high-cadence radial velocity data obtained with the High Resolution Spectrograph on the Hobby-Eberly Telescope, and relative astrometry with the FGS-1r instrument on the Hubble Space Telescope. We performed a simultaneous analysis of these data in order to characterize the orbit of the companions thoroughly. This establishes the actual mass of HD 136118 b, M$_b$=63$^{+22}_{-13}$M$_J$, in contrast to the minimum mass determined from the radial velocity data only, M$_b$ sin \textit{i} $\sim$12 M$_J$. Therefore, the low-mass companion to HD 136118 is now identified as a likely brown-dwarf residing in the "brown-dwarf desert". Our results for HD 33636 are consistent with those found in the literature. For the latter object we also present experimental infrared interferometric observations with the AMBER instrument at the Very Large Telescope Interferometer. We have identified visibility variations consistent with an additional light with flux ratio of 30\%. This result is incompatible with those obtained from the other two experiments, i.e. a binary system that is composed of a GO V primary star and an M-dwarf companion.
Neste trabalho são desenvolvidas técnicas observacionais e análise de dados para o estudo de candidatos a exoplanetas e companheiras de baixa massa detectados via velocidades radiais. Foram observados os sistemas HD 136118 e HD 33636. As observações incluem medidas de alta-cadência de velocidades radiais com o espectrógrafo de alta resolução do telescópio Hobby-Eberly e medidas astrométricas com o Sensor de Guiagem Fina 1r do telescópio espacial HST. Os dados de ambos experimentos foram analisados simultaneamente para a caracterização completa da órbita das companheiras. O trabalho resultou na determinação da massa verdadeira de HD 136118 b, M$_b$=63$^{+22}_{-13}$M$_J$. Essa massa é relativamente maior que a massa mínima determinada anteriormente via velocidades radiais, M$_b$ sin \textit {i} $\sim$ 12 M$_J$. Portanto, HD 136118 b é identificada como uma provável anã-marrom que reside no "deserto das anãs-marrons". Os resultados obtidos para o sistema HD 33636 são consistentes com os encontrados na literatura. Para HD 33636, ainda foram realizadas medidas interferométricas experimentais no infravermelho com o instrumento AMBER e três telescópios do Very Large Telescope Interferometer . Foram identificadas variações na visibilidade interferométrica que são consistentes com uma luz adicional com razão de fluxos de aproximadamente 30\%. Este resultado é inconsistente com os resultados dos dois primeiros experimentos, ou seja, um sistema binário constituído por uma estrela primária do tipo GO V e uma companheira anã do tipo M.

One of the most difficult tasks towards designing earthquake resistant structures is the determination of critical earthquakes. Conceptually, these are the ground motions that would induce the critical response in the structures being designed. The quantification of this concept, however, is not easy. Unlike the linear response of a structure, which can often be obtained by using a single spectrally modified ground acceleration history, the nonlinear response is strongly dependent on the phasing of ground motion and the detailed shape of its spectrum. This necessitates the use of a suite (bin) of ground acceleration histories having phasing and spectral shapes appropriate for the characteristics of the earthquake source, wave propagation path, and site conditions that control the design spectrum. Further, these suites of records may have to be scaled to match the design spectrum over a period range of interest, rotated into strike-normal and strike-parallel directions for near-fault effects, and modified for local site conditions before they can be input into time-domain nonlinear analysis of structures. The generation of these acceleration histories is cumbersome and daunting. This is especially so due to the sheer magnitude of the data processing involved. The purpose of this thesis is the development and documentation of PC-based computational tools (hereinafter called EQTools) to provide a rapid and consistent means towards systematic assembly of representative strong ground motions and their characterization, evaluation, and modification within a performance-based seismic design framework. The application is graphics-intensive and every effort has been made to make it as user-friendly as possible. The application seeks to provide processed data which will help the user address the problem of determination of the critical earthquakes. The various computational tools developed in EQTools facilitate the identification of severity and damage potential of more than 700 components of recorded earthquake ground motions. The application also includes computational tools to estimate the ground motion parameters for different geographical and tectonic environments, and perform one-dimensional linear/nonlinear site response analysis as a means to predict ground surface motions at sites where soft soils overlay the bedrock. While EQTools may be used for professional practice or academic research, the fundamental purpose behind the development of the software is to make available a classroom/laboratory tool that provides a visual basis for learning the principles behind the selection of ground motion histories and their scaling/modification for input into time domain nonlinear (or linear) analysis of structures. EQTools, in association with NONLIN, a Microsoft Windows based application for the dynamic analysis of single- and multi-degree-of-freedom structural systems (Charney, 2003), may be used for learning the concepts of earthquake engineering, particularly as related to structural dynamics, damping, ductility, and energy dissipation.
Master of Science

Sources of high nitrate concentrations in ground water from the western part of the Salt River Valley in central Arizona historically have not been well identified. This thesis presents chemical and isotopic data for surface and ground water collected in the study area during 1990. These data are used to characterize general ground-water chemistry in the study area and to evaluate the applicability of 87 and delta11B data to identify different types of nitrate sources. Ground water from northern and southern regions in the study area are differentiated by major ion compositions, metal concentrations, pH, and 3 and 87 data. 87 data identify ground-water flowpaths in the study area. delta11 and delta7Li values are useful for the identification of sewage treatment outflow. delta7Li data may also identify leachates from manure. Effects from a halite deposit on ground water are also distinctive.

The power/ground plane structure within an electronic system not only delivers power, but also provides return path for the currents associated with the propagating signals. The cavity resonances within the power/ground plane structure affect the signal integrity of the system at high frequencies. The chip complexity and clock speed continue to increase and new structures, such as meshed planes and electromagnetic bandgap structures, are used in plane pair structure design. The signal integrity analysis of the power/ground plane structure becomes exceedingly important and challenging.The primary goal of this research is an in-depth investigation of the impact of the cavity resonances associated with the plane pair structure on the signal integrity. This includes development of modeling, simulation, and measurement methodologies for accurate and efficient characterization or prediction of the time/frequency domain electrical characteristics of power/ground plane pair structures. This research is divided into three parts. First, new SPICE compatible models are proposed for the new structures, such as the meshed plane and EBG embedded plane pair designs, so that the power/ground plane designs with these new structures can be simulated efficiently. Second, the accuracy of the simulation results is vital. The behavior of the benchmark structures is simulated and simulation results are verified either experimentally or by comparing with those from tools that are proven to be accurate. Third, high frequency measurement data is vulnerable to all parasitic parameters. The factors that affect the accuracy of measured data are investigated and methods to improve the accuracy of the measured data are proposed and verified.

Hedgehog related genes have been shown to play a major role in development in all deuterostomes. In C.elegans, such genes have been found where the similarity is restricted to the C-terminal domain. This work has focused on the hedgehog related C.elegans proteins called ground (grd), ground-like (grl), and wart (wrt) which appear to form a unique structural family.These proteins are cysteine rich and have conserved cysteine patterns which, together with thethought that they are secreted, are expected to be in disulfide form. Since the extracellular environment is very oxidizing and due to the conserved cysteine pattern, disulfide bonds are thought to play a big part in the folding and stabilization of these proteins. The stability of the protein and the formation of a disulfide bond are related through a thermodynamic cycle, which insures that the stabilization of the protein by the disulfide is reflected by the identical stabilization of the disulfide by the protein. Practically, there are numerous parameters that can be used to try to achieve the correct disulfide bonds and folding, when doing in vitro trials, some of which were used in this project. C.elegans proteins grd-5, grd-13, grl-24, wrt-3 and wrt-5 were studied in this project. All of the proteins were expressed and purified with success, with theexception of grl-24. All constructs formed inclusion bodies. Some refolding attempts were performed on grd-13 and wrt-3. The presence of a disulfide bond in refolded grd-13 was demonstrated using chemical fragmentation. In general, these attempts did not give correctly folded proteins but provide a foundation to continue experiments aimed at producing a native-like protein for structural and functional studies.

The objective of this study is to evaluate the regional differences between the worldwide based NGA-W1 ground motion models and available Turkish strong ground motion dataset and make the required adjustments in the NGA-W1 models. A strong motion dataset using parameters consistent with the NGA ground motion models is developed by including strong motion data from Turkey. Average horizontal component ground motion is computed for response spectral values at all available periods using the GMRotI50 definition consistent with the NGA-W1 models. A random-effects regression with a constant term only is used to evaluate the systematic differences in the average level of shaking. Plots of residuals are used to evaluate the differences in the magnitude, distance, and site amplification scaling between the Turkish dataset and the NGA-W1 models. Model residuals indicated that the ground motions are overestimated by all 5 NGA-W1 models significantly, especially for small-to-moderate magnitude earthquakes. Model residuals relative to distance measures plots suggest that NGA-W1 models slightly underestimates the ground motions for rupture distances within 100-200 km range. Models including the aftershocks over-predict the ground motions at stiff soil/engineering rock sites. The misfit between the actual data and model predictions are corrected with adjustments functions for each scaling term. Turkey-Adjusted NGA-W1 models proposed in this study are compatible with the Turkish strong ground motion characteristics and preserve the well-constrained features of the global models. Therefore these models are suitable candidates for ground motion characterization and PSHA studies conducted in Turkey.

Radio magnetotellurics (RMT), crosshole ground penetrating radar (GPR), and crosshole electrical resistance tomography (ERT) were applied in a range of hydrogeological applications where geophysical data could improve hydrogeological characterization. A profile of RMT data collected over highly resistive granite was used to map subhorizontal fracture zones below 300m depth, as well as a steeply dipping fracture zone, which was also observed on a coinciding seismic reflection profile. One-dimensional inverse modelling and 3D forward modelling with displacement currents included were necessary to test the reliability of features found in the 2D models, where the forward models did not include displacement currents and only lower frequencies were considered. An inversion code for RMT data was developed and applied to RMT data with azimuthal electrical anisotropy signature collected over a limestone formation. The results indicated that RMT is a faster and more reliable technique for studying electrical anisotropy than are azimuthal resistivity surveys. A new sequential inversion method to estimate hydraulic conductivity fields using crosshole GPR and tracer test data was applied to 2D synthetic examples. Given careful surveying, the results indicated that regularization of hydrogeological inverse problems using geophysical tomograms might improve models of hydraulic conductivity. A method to regularize geophysical inverse problems using geostatistical models was developed and applied to crosshole ERT and GPR data collected in unsaturated sandstone. The resulting models were geologically more reasonable than models where the regularization was based on traditional smoothness constraints. Electromagnetic geophysical techniques provide an inexpensive data source in estimating qualitative hydrogeological models, but hydrogeological data must be incorporated to make quantitative estimation of hydrogeological systems feasible.

Efficiency of probabilistic seismic hazard analysis mainly depends on the individual successes of its complementing components
such as source characterization and ground motion intensity prediction. This study contributes to major components of the seismic hazard workflow including magnitude &ndash
rupture dimension scaling relationships, and ground motion intensity prediction. The study includes revised independent models for predicting rupture dimensions in shallow crustal zones, accompanied by proposals for geometrically compatible rupture area-length-width models which satisfy the rectangular rupture geometry assumption. Second main part of the study focuses on developing a new ground motion prediction model using data from Turkish strong ground motion database. The series of efforts include, i) compilation and processing of a strong motion dataset, ii) quantifying parameter uncertainties of predictive parameters such as magnitude and source to site distance
and predicted accelerations due to uncertainty in site conditions and response, as well as uncertainty due to random orientation of the sensor, iii) developing a ground response model as a continuous function of peak ground acceleration and shear wave velocity, and finally, iv) removing bias in predictions due to uneven sampling of the dataset. Auxiliary components of the study include a systematic approach to source characterization problem, with products ranging from description of systematically idealized and documented seismogenic faults in Anatolia, to delineation, magnitude-recurrence parameterization, and selection of maximum magnitude earthquakes. Last stage of the study covers the development of a custom computer code for probabilistic seismic hazard assessment which meets the demands of modern state of practice.

Il est maintenant bien établi que les cirrus ont un impact important sur le climat. Cependant, l'estimation de cet effet est difficile car notre connaissance des propriétés microphysiques de ce type de nuage est encore incertaine. L'objectif de cette thèse est donc d’améliorer notre compréhension de la microphysique complexe du cirrus composé principalement de cristaux de glace de forme irrégulière et d'estimer ainsi un contenu en glace (ice water content, IWC) plus précis. Pour cela, nous avons développé un algorithme permettant de restituer le profil vertical d'IWC du cirrus. La méthodologie considère une synergie entre les mesures d'un lidar et celles d'un radiomètre infrarouge thermique (IRT) effectuées depuis le sol, via une méthode d'estimation optimale. Ce travail s’est déroulé en trois étapes: (1) Le contenu en glace intégré verticalement (ice water path, IWP) est estimé à partir des mesures passives IRT. (2) L'information sur la distribution verticale d'IWC à l'intérieur du nuage est obtenue avec les mesures actives du lidar. Cette restitution dépend fortement du rapport entre la rétrodiffusion et l'extinction des cristaux de glace obtenu avec un modèle microphysique. La fonction de phase du modèle utilisée pour définir ce rapport ne prend pas en compte le pic de rétrodiffusion. Nous montrons que cette hypothèse aboutit à des résultats non réalistes par rapport aux mesures IRT. (3) Par conséquent, les deux types d’informations sont combinées en synergie pour estimer, lors de la restitution des profils verticaux d'IWC, un facteur correctif permettant de rendre compte de ce pic de rétrodiffusion. Finalement, les résultats et les hypothèses associées sont discutés
There is a broad consensus that cirrus clouds strongly influence the climate of the Earth. However, their net radiative effect is still poorly quantified nowadays due to an insufficient knowledge of their microphysical properties. This thesis aims to improve our understanding of the complex microphysics of this cloud type mainly composed of irregularly shaped ice crystals and thereby improve estimates of the ice water content (IWC). For this purpose, we developed an algorithm to retrieve vertical profiles of the IWC of cirrus clouds. The methodology combines the measurements of a ground-based lidar and a thermal infrared (TIR) radiometer in a common optimal estimation framework. It follows three steps: (1) An algorithm to retrieve the vertically integrated amount of ice (ice water path, IWP) from the passive TIR measurements is established. (2) The information about the vertical distribution of the IWC inside the cloud is obtained from the active lidar measurements. These retrievals strongly depend on the backscatter-to-extinction ratio of the ice crystals which is obtained from a bulk ice microphysical model. The scattering phase function of this model used to define the backscatter-to-extinction ratio assumes a flat ending without backscattering peak. We show that this assumption is unrealistic since it results in the retrieval of IWC profiles which are inconsistent with the TIR measurements. (3) Consequently, both types of measurements are combined in a synergistic algorithm allowing to estimate together with the IWC profiles a correction factor for the phase function in backscattering direction. Finally, the retrieval results and associated hypotheses are discussed

Este trabalho tem como objetivo a caracterização de um sistema de solos, evidenciando os parâmetros que possam esclarecer sua dinâmica e contribuir para a definição de critérios que possam determinar a aptidão destes solos como receptores de efluentes. Trata-se de uma área experimental de estudos, contígua à Estação de Tratamento de Esgoto do município de Lins (SP), onde efluentes são gerados a partir do tratamento de esgoto por sistema de lagoas de estabilização. Nesta área, vem sendo aplicada a técnica de irrigação com efluentes (fertirrigação). Os solos, situados ao longo de uma vertente com ligeira inclinação, foram caracterizados através de análises morfológicas, granulométricas, químicas, mineralógicas e micromorfológicas, realizadas em amostras coletadas em seis trincheiras abertas ao longo de duas topossequências, dispostas segundo o eixo de maior declive da vertente. Os solos são desenvolvidos a partir dos sedimentos arenosos da Formação Adamantina (Grupo Bauru) e constituem um sistema Latossolo – Argissolo, onde a transição Bw – Bt ocorre lateralmente do topo para a base da vertente. Foram identificadas quatro fases pedogenéticas nesta associação de solos. As duas primeiras, argiluviação e adensamento de partículas, responsáveis pela formação dos horizontes texturais, foram superpostas pelos processos de latossolização e hidromorfismo, atuantes na dinâmica atual destes solos. Análises micromorfológicas mostraram tratar-se de solos com intensa porosidade, caracterizada pelo empilhamento dos grãos do esqueleto quartzoso, amplamente predominante, e pelo arranjo entre os microagregados granulares. A permeabilidade é ainda favorecida pela intensa ação da mesofauna. Os solos são distróficos, com alta saturação por alumínio e compostos por caolinita e óxidos de ferro. Por se constituirem num sistema frágil, a disposição de quaisquer tipos de resíduos nestes solos, requer o monitoramento constante de suas propriedades, tanto para a manutenção, quanto para a recuperação da qualidade desta cobertura pedológica.
The purpose of this study is to characterize a soil system, identifying the properties which can elucidate its dynamics and to define criterions for the ability of these soils to constitute an effluent disposal land. The experimental area is located nearby the Sewage Treatment Station (STS), in Lins (SP) and the effluent is proceeded for secundary treatment. In this area, is being applied the technique of fertirrigation. The soils are situated on a downslope and were characterized beside morphological, particle size, chemicals, mineralogicals and micromorphologicals analyses on samples collected in six profiles along two toposequences, across the axis of maximun gradient on downslope. These soils are expanded from sandstones of Adamantina Formation (Bauru Group) and compose an Oxisol-Ultisol system. The Bw-Bt transition accurs laterally, from the upper to the lowest part of downslope. It was recognized four pedogenetic phasis. Both first, argilluviation and compressed layer, explain the formation of argillic horizons and were superimposed from latossolization and hydromorphism, both last actuating on the actual dynamics of these soils. Micromorphological analysis showed that these soils are too porous, characterized for packing of skeletic grains and between granular aggregates. The permeability is increased by the activity of mesofaunal. These soils are dystrophics, have high aluminium saturation and are composed for kaolinite and iron oxides. This system is fragile, thus, the deposal of any kind of residues on these soils, needs the constant warning of all of their properties, so to the maintenance and also the recover of the quality of this pedologic cover.

The impact of mineral dust upon climate, ecosystems and air quality represents a major scientific and societal issue. The aim goals of the present Ph.D. Thesis are to evaluate the behaviour and to improve the forecasting skills of a regional dust model and to characterize the desert dust content in Northern Africa, Europe and Middle East. An aerosol characterization was performed using long-term series of aerosol optical depth (AOD) from AERONET sun photometers. The results showed that mineral dust was the most important constituent in Northern Africa and Arabia. Small particles were abundant in sites close to urban and industrial areas of Continental and Eastern Europe and Middle East, and important contributions of biomass burning were observed in the sub-Sahel region in winter. Desert dust transport to Southern Europe was observed from spring to autumn and decreasing with latitude with contributions above 40% to the aerosol column load. Dust models are essential to complement dust-related observations, understand the dust processes and predict the impact of dust on air quality. Despite that the BSC-DREAM8b model has reached a level of delivering reliable operational dust forecasts, it is necessary to conduct an extensive evaluation of its behaviour. The BSC-DREAM8b and the original DREAM models and different research model versions were evaluated over Northern Africa, Mediterranean and Middle East using AERONET measurements and seasonal averages from satellite aerosol products. The model evaluation highlighted that BSC-DREAM8b and DREAM strongly underestimated the dust fields in the Sahel during winter and overestimated dust concentrations during spring rainy events in the Mediterranean. The introduction of new dry deposition scheme and an updates in the wet deposition scheme improved the long-range transport, although significant underestimation remained in the Sahel in winter. The inclusion of a preferential source mask improved the localization of the main North African sources and the long-range dust transport to Europe and Atlantic regions. The inclusion of a more physically-based dust emission scheme with a new soil texture database led to reasonably good results at source areas and subsequent long-range transport. In this case, the use of a preferential source mask didn¿t introduce significant improvements. The long-range dust transport over Europe was evaluated and analysed with an annual simulation of the CALIOPE air quality modelling system. CALIOPE includes CMAQ which calculates biogenic, anthropogenic and sea salt aerosol; and BSC-DREAM8b which provides desert dust. For the evaluation, we used daily PM10, PM2.5 and aerosol components from the EMEP/CREATE network; total, coarse and fine AOD from AERONET and seasonal averages from satellite aerosol products. Overall CALIOPE could reproduce reasonably well the daily variability of the main components and the seasonal aerosol patterns in Europe. However, the PM and AOD levels were underestimated. The most underestimated aerosol components were carbonaceous matter and secondary inorganic aerosols (SIA). A simple model bias correction based on the chemical composition observations was applied to the model simulation to provide an estimation of the spatial and seasonal distribution of aerosols over Europe. The simulated aerosol concentrations presented maximum values over the industrialized and populated areas of the Po Valley and the Benelux regions. SIA were dominant in the fine fractions representing up to 80% of the aerosol budget in latitudes beyond 40ºN. A second maximum was detected over Eastern and Southern Europe. High values in Southern Europe were linked to Saharan dust transport which contributed up to 40% of the total aerosol mass. Maxima dust seasonal concentrations were found between spring and early autumn. These results showed that desert dust is the main responsible of the exceedances of the PM10 EU air quality threshold in large areas south of 45ºN.
Una gran quantitat de pols que és mobilitzada en les regions àrides del planeta, és injectada a l’atmosfera sota condicions meteorològiques favorables. A partir de mesures terrestres i de satèl·lit, a més a més d’estimacions obtingudes a partir de models, es calcula que en tot el planeta s’emeten entre centenars i milers de megatones de pols per any. L’impacte que té la pols mineral en el clima, els ecosistemes i la qualitat de l’aire, i per tant, en la salut humana i les activitats econòmiques, representa una qüestió social i científica de gran rellevància. La font més important d’emissió de pols mineral a nivell global és la regió del Sàhara. Els principals objectius de la present tesi doctoral són el d'avaluar el comportament i el de millorar les capacitats de predicció d'un model regional de pols així com el de caracteritzar el contingut de pols desèrtica en el nord d'Àfrica, Orient Mitjà i Europa. En aquest marc de treball, el model regional de pols BSC-DREAM8b i els fotòmetres de la xarxa internacional AERONET són les principals eines que seràn utilitzades en el transcurs de la present investigació. La comparació entre valors observats i simulats no pot ser adequadament entesa si les mesures no estan separades en els seus components fonamentals. Així, es va dur a terme una caracterització d'aerosols per al nord d'Àfrica, Europa i Orient Mitjà. Aquesta caracterització està basada en sèries d'espessor òptic d'aerosols (AOD; Aerosol Optical Depth en anglès) dels fotòmetres de la xarxa AERONET. L'anàlisi d'aquesta base de dades es va realitzar aplicant el mètode de Gobbi i co-autors. Aquest mètode gràfic permet deduir diferents propietats òptiques i físiques dels aerosols (com són el radi efectiu del mode fi i la contribució de les fraccions fines i gruixudes a l’AOD), a més a més, de diferenciar entre diferents processos que fan augmentar el valor de l’AOD com són la humidificació i/o coagulació de les fraccions fines o l'increment de partícules més gruixudes a causa de la presència de núvols. Els resultats van mostrar que la pols mineral és l'aerosol més important al nord d'Àfrica i Aràbia. En estacions properes a zones urbanes i industrials de regions continentals i de l'est d'Europa i Orient Mitjà es van observar partícules fines associades a fonts antropogèniques. També es van detectar importants contribucions en les fraccions fines degudes a la crema de biomassa a la zona del sub-Sahel durant l'hivern. El transport de pols desèrtica cap al sud d'Europa està associat a determinats patrons meteorològics estacionals. Com a resultat, en zones del sud d'Europa, la pols desèrtica es va observar entre primavera i tardor, i la seva contribució (que va arribar superar el 40%) decreixia cap a latituds més al nord. En aquest darrer cas, la pols desèrtica acostumava a trobar-se barrejada amb altres tipus d'aerosols d'origen antropogènic Els models de pols són essencials per complementar les observacions, entendre els processos associats al cicle de la pols i predir el seu impacte en les concentracions en superfície del material particulat (PM; Particulate Matter en anglès). En particular, els models regionals són adequats per a la simulació d'episodis individuals d’instrusió de pols desèrtica. Actualment, el model de pols BSC-DREAM8b és mantingut i desenvolupat en el Barcelona Supercomputing Center – Centre Nacional de Supercomputació (BSC-CNS). En els darrers anys, el model ha proporcionat prediccions diàries de concentracions de pols desèrtica en dos dominis: Nord d'Àfrica-Europa – Europa - Orient Mitjà i Àsia. A pesar que el BSCDREAM8b ha arribat a aconseguir una qualitat de pronòstic operacional capaç de reproduir els episodis d'intrusió saharians més importants que afecten al Mediterrani i Europa, és necessari avaluar el seu comportament en regions font de pols. En aquest context, el model BSC-DREAM8b i la seva versió original, DREAM, així com diferents versions experimentals, van ser avaluats per a un cicle estacional complet utilitzant les dades de la xarxa AERONET i promitjos estacionals de productes d'aerosols de diferents satèl·lits pel Nord d'Àfrica, Orient Mitjà i Europa. Els resultats de l'avaluació del model van mostrar que tant el BSC-DREAM8b com el DREAM subestimaven les concentracions de pols a la regió del Sahel durant l'estació hivernal del Harmattan. Per contra, importants sobreestimacions en l'oest del Mediterrani es van detectar coincidint amb episodis plujosos a la primavera. L’inclusió d'un nou esquema de deposició seca a més de l'actualització de la relació de rentat en l'esquema de deposició humida del model, van aconseguir millores en el transport a llarga distància, en particular sobre el Mediterrani malgrat que les subestimacions a la zona del Sahel van continuar sent persistents a l'hivern. La introducció d'una màscara de fonts preferents basada en la topografia del terreny en l'esquema d'emissió va millorar la localització de les principals regions font en el Nord d'Àfrica. Com a conseqüència, es van observar millores en el transport de llarga distància cap a Europa i les regions Atlàntiques. La inclusió d'un nou esquema d'emissió (que inclou parametritzacions físiques més complexes) a més d'una nova base de dades de textura de sòls va aconseguir bons resultats en regions font així com en regions afectades pel transport de pols a llarga distància. En aquest cas, l’introducció d'una màscara de fonts preferents en l'esquema d'emissió no va mostrar significants millores en comparació dels valors observats. A Europa, es poden trobar diferents tipus d'aerosols associats a diferents fonts d'emissió (tant naturals com antropogèniques) que s’han de tenir en compte quan s'analitzen les contribucions dels aerosols sobre el continent europeu. El transport de pols sahariana cap a sud d'Europa va ser avaluat i analitzat mitjançant una simulació del sistema de modelització de qualitat de l'aire CALIOPE. El sistema de modelització CALIOPE integra un conjunt de models dels quals el BSC-DREAM8b i el model fotoquímic CMAQ proporcionen les estimacions d'aerosols. Per a l'avaluació de CALIOPE es van utilitzar diverses fonts de dades de xarxes en superfície (com la xarxa europea de qualitat de l'aire EMEP/CREATE i la xarxa de AERONET) i mitjanes estacionals de productes d'aerosols de satèl.lits. L'avaluació va mostrar que malgrat subestimar les concentracions d'aerosols, CALIOPE va ser capaç de capturar les variabilitats diàries observades en les estacions en superfície així com reproduir els patrons estacionals observats en els productes de satèl·lit. L'avaluació dels aerosols per components va mostrar que les espècies químiques amb major subestimació pel que fa a les observacions estaven associades a les fraccions fines de carbó elemental i orgànic així com els aerosols secundaris inorgànics (nitrats, sulfats i amoni). Com a resultat, es va aplicar un senzill mètode de correcció de l’error als resultats de la simulació basat en les observacions de la composició química per tal de mostrar una estimació espaial i temporal de la distribució dels diferents aerosols presents a Europa. L'anàlisi de d’aquesta simulació va mostrar que les màximes concentracions d'aerosols es localitzen a les zones poblades i industrialitzades del Benelux i de la Vall del Po. Aquests màxims estan associats a les fraccions fines compostes d'aerosols secundaris inorgànics (observant-se contribucions de més del 80%). Màxims secundaris es van detectar a l'est i sud d'Europa. Les altes concentracions en el sud d'Europa s’associaven al transport de pols sahariana que contribuïa en més d'un 40% al total de la massa en columna. Prop de la superfície, les màximes concentracions estacionals associades al transport de pols (> 30 microg/m3) van ser observades entre primavera i estiu. A més a més, els resultats de la simulació anual d'aerosols per Europa va mostrar que el transport de pols sahariana és el principal responsable de la superació del límit diari de PM10 establert per la Unió Europea (50 microg/m3) en extenses àrees al sud dels 45ºN.

Tunable diode laser absorption spectroscopy using an external cavity diode laser operating in the infra-red has been developed to monitor CO2 in the freestream of the Longshot hypervelocity facility at the Von Karman Institute for Fluid Dynamics. The Longshot facility offers a unique European facility for ground testing and numerical validation applications, however, some of the traditional data rebuilding aspects are in question. A non-intrusive absorption

sensor could significantly aid in improving the knowledge of freestream static values thereby improving the models used in data rebuilding and numerical simulation. The design of such a sensor also expands the spectroscopic capabilities of the Von Karman Institute.

The absorption sensor is designed around the single P12 (00001)-(30013) rovibrational transition near 1.6µm (6218.09cm-1 specifically) which yields relatively weak direct absorption levels at about 3.5% per meter for typical Longshot freestream conditions. However, when handled carefully, adequate signal-to-noise can be acquired to exploit significant flow information. By being able to operate in this range, total sensor cost can be easily an a factor of two or more cheaper than sensors designed for the deeper infrared. All sensor elements were mounted to a compact portable optics bench utilizing single-mode optical fibers to allow for quick installation at different facilities by eliminating tedious optical realigning. Scans at 600Hz were performed over 20ms of the 40ms test time to extract core static temperature, pressure and velocity.

These results are compared with the current state of the Longshot data rebuild method. The non-uniform flow properties of the shear layer and test cabin rested gas accumulation was of an initial concern. The temperature and density gradients along with significant radial velocity components could result in DLAS temperature, pressure and velocity that are significantly different than that of the target freestream inviscid core values. Fortunately, with the proper selection of the P12 rotational number, this effect could be more or less ignored as the higher temperature and lower density gas of this region is relatively transparent.

Ultimately, acquired temperature and density were moderately accurate when compared to Longshot rebuilt results owing primarily to the baseline extraction which poses issues for such low absorption signals. However, the extracted velocity data are quite accurate. This is a definite puls for the sensor as the freestream enthalpy of cold hypersonic facilities is dictated primarily by the kinetic energy contribution. Being able to compare velocity gives insight to the level of vibration non-equilibrium in the flow. The velocity of the DLAS and the Longshot rebuild are quite close. This adds more weight to the argument that vibrational excitation is very low (if present at all) in the free stream and that the van de derWaals equation of state usage and constant specific heat assumption might be an adequate model for the data rebuild after all.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

The anisotropy of the Biscayne Aquifer which serves as the source of potable water for Miami-Dade County was investigated by applying geophysical methods. Electrical resistivity imaging, self potential and ground penetration radar techniques were employed in both regional and site specific studies. In the regional study, electrical anisotropy and resistivity variation with depth were investigated with azimuthal square array measurements at 13 sites. The observed coefficient of electrical anisotropy ranged from 1.01 to 1.36. The general direction of measured anisotropy is uniform for most sites and trends W-E or SE-NW irrespective of depth. Measured electrical properties were used to estimate anisotropic component of the secondary porosity and hydraulic anisotropy which ranged from 1 to 11% and 1.18 to 2.83 respectively. 1-D sounding analysis was used to models the variation of formation resistivity with depth. Resistivities decreased from NW (close to the margins of the everglades) to SE on the shores of Biscayne Bay. Porosity calculated from Archie's law, ranged from 18 to 61% with higher values found along the ridge. Higher anisotropy, porosities and hydraulic conductivities were on the Atlantic Coastal Ridge and lower values at low lying areas west of the ridge. The cause of higher anisotropy and porosity is attributed to higher dissolution rates of the oolitic facies of the Miami Formation composing the ridge. The direction of minimum resistivity from this study is similar to the predevelopment groundwater flow direction indicated in published modeling studies. Detailed investigations were carried out to evaluate higher anisotropy at West Perrine Park located on the ridge and Snapper Creek Municipal well field where the anisotropy trend changes with depth. The higher anisotropy is attributed to the presence of solution cavities oriented in the E-SE direction on the ridge. Similarly, the change in hydraulic anisotropy at the well field might be related to solution cavities, the surface canal and groundwater extraction wells.

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission provides unique measurements of vertical profiles of aerosols and clouds and their properties during day and night-time over all types of surfaces. This information has the potential to significantly improve our understanding of the properties and effects of aerosol and clouds. This dissertation presents the results of a comprehensive analysis of CALIPSO lidar (version 2 and version 3.01) data in conjunction with A-Train satellite and ground-based observations aimed at characterizing mineral aerosol in East Asia and other major dust sources. The specific objectives were to characterize the spatial distribution and properties of atmospheric dust in the dust source regions using new CALIOP (version 3.01) data in conjunction with satellite MODIS, OMI, and CloudSat data and ground-based meteorological and lidar data; investigate changes in the vertical distribution and properties of dust during mid- and long-range transport; perform a modeling of the optical properties of nonspherical dust particles, and assess the radiative forcing and heating/cooling rates of atmospheric dust by performing radiative transfer modeling constrained by satellite data in major dust source regions.

[EN] Over time, due to multiple operational and maintenance activities, the networks of water supply systems (WSSs) undergo interventions, modifications or even are closed. In many cases, these activities are not properly registered. Knowledge of the paths and characteristics (status and age, etc.) of the WSS pipes is obviously necessary for efficient and dynamic management of such systems. This problem is greatly augmented by considering the detection and control of leaks. Access to reliable leakage information is a complex task. In many cases, leaks are detected when the damage is already considerable, which brings high social and economic costs. In this sense, non-destructive methods (e.g., ground penetrating radar - GPR) may be a constructive response to these problems, since they allow, as evidenced in this thesis, to ascertain paths of pipes, identify component characteristics, and detect primordial water leaks. Selection of GPR in this work is justified by its characteristics as non-destructive technique that allows studying both metallic and non-metallic objects. Although the capture of information with GPR is usually successful, such aspects as the capture settings, the large volume of generated information, and the use and interpretation of such information require high level of skill and experience. This dissertation may be seen as a step forward towards the development of tools able to tackle the problem of lack of knowledge on the WSS buried assets. The main objective of this doctoral work is thus to generate tools and assess their feasibility of application to the characterization of components of WSSs from GPR images. In this work we have carried out laboratory tests specifically designed to propose, develop and evaluate methods for the characterization of the WSS buried components. Additionally, we have conducted field tests, which have enabled us to determine the feasibility of implementing such methodologies under uncontrolled conditions. The methodologies developed are based on techniques of intelligent data analysis. The basic principle of this work has involved the processing of data obtained through the GPR to look for useful information about WSS components, with special emphasis on the pipes. After performing numerous activities, one can conclude that, using GPR images, it is feasible to obtain more information than the typical identification of hyperbolae currently performed. In addition, this information can be observed directly, e.g. more simply, using the methodologies proposed in this doctoral work. These methodologies also prove that it is feasible to identify patterns (especially with the preprocessing algorithm termed Agent race) that provide fairly good approximation of the location of leaks in WSSs. Also, in the case of pipes, one can obtain such other characteristics as diameter and material. The main outcomes of this thesis consist in a series of tools we have developed to locate, identify and visualize WSS components from GPR images. Most interestingly, the data are synthesized and reduced so that the characteristics of the different components of the images recorded in GPR are preserved. The ultimate goal is that the developed tools facilitate decision-making in the technical management of WSSs, and that such tools can even be operated by personnel with limited experience in handling non-destructive methodologies, specifically GPR.
[ES] Con el paso del tiempo, y debido a múltiples actividades operacionales y de mantenimiento, las redes de los sistemas de abastecimiento de agua (SAAs) sufren intervenciones, modificaciones o incluso, son clausuradas, sin que, en muchos casos, estas actividades sean correctamente registradas. El conocimiento de los trazados y características (estado y edad, entre otros) de las tuberías en los SAAs es obviamente necesario para una gestión eficiente y dinámica de tales sistemas. A esta problemática se suma la detección y el control de las fugas de agua. El acceso a información fiable sobre las fugas es una tarea compleja. En muchos casos, las fugas son detectadas cuando los daños en la red son ya considerables, lo que trae consigo altos costes sociales y económicos. En este sentido, los métodos no destructivos (por ejemplo, ground penetrating radar - GPR), pueden ser una respuesta a estas problemáticas, ya que permiten, como se pone de manifiesto en esta tesis, localizar los trazados de las tuberías, identificar características de los componentes y detectar las fugas de agua cuando aún no son significativas. La selección del GPR, en este trabajo se justifica por sus características como técnica no destructiva, que permite estudiar tanto objetos metálicos como no metálicos. Aunque la captura de información con GPR suele ser exitosa, la configuración de la captura, el gran volumen de información, y el uso y la interpretación de la información requieren de alto nivel de habilidad y experiencia por parte del personal. Esta tesis doctoral se plantea como un avance hacia el desarrollo de herramientas que permitan responder a la problemática del desconocimiento de los activos enterrados de los SAAs. El objetivo principal de este trabajo doctoral es, pues, generar herramientas y evaluar la viabilidad de su aplicación en la caracterización de componentes de un SAA, a partir de imágenes GPR. En este trabajo hemos realizado ensayos de laboratorio específicamente diseñados para plantear, elaborar y evaluar metodologías para la caracterización de los componentes enterrados de los SAAs. Adicionalmente, hemos realizado ensayos de campo, que han permitido determinar la viabilidad de aplicación de tales metodologías bajo condiciones no controladas. Las metodologías elaboradas están basadas en técnicas de análisis inteligentes de datos. El principio básico de este trabajo ha consistido en el tratamiento adecuado de los datos obtenidos mediante el GPR, a fin de buscar información de utilidad para los SAAs respecto a sus componentes, con especial énfasis en las tuberías. Tras la realización de múltiples actividades, se puede concluir que es viable obtener más información de las imágenes de GPR que la que actualmente se obtiene con la típica identificación de hipérbolas. Esta información, además, puede ser observada directamente, de manera más sencilla, mediante las metodologías planteadas en este trabajo doctoral. Con estas metodologías se ha probado que también es viable la identificación de patrones (especialmente el pre-procesado con el algoritmo Agent race) que proporcionan aproximación bastante acertada de la localización de las fugas de agua en los SAAs. También, en el caso de las tuberías, se puede obtener otro tipo de características tales como el diámetro y el material. Como resultado de esta tesis se han desarrollado una serie de herramientas que permiten visualizar, identificar y localizar componentes de los SAAs a partir de imágenes de GPR. El resultado más interesante es que los resultados obtenidos son sintetizados y reducidos de manera que preservan las características de los diferentes componentes registrados en las imágenes de GPR. El objetivo último es que las herramientas desarrolladas faciliten la toma de decisiones en la gestión técnica de los SAAs y que tales herramientas puedan ser operadas incluso por personal con una experiencia limitada en el manejo
[CAT] Amb el temps, a causa de les múltiples activitats d'operació i manteniment, les xarxes de sistemes d'abastament d'aigua (SAAs) se sotmeten a intervencions, modificacions o fins i tot estan tancades. En molts casos, aquestes activitats no estan degudament registrats. El coneixement dels camins i característiques (estat i edat, etc.) de les canonades d'aigua i sanejament fa evident la necessitat d'una gestió eficient i dinàmica d'aquests sistemes. Aquest problema es veu augmentat en gran mesura tenint en compte la detecció i control de fuites. L'accés a informació fiable sobre les fuites és una tasca complexa. En molts casos, les fugues es detecten quan el dany ja és considerable, el que porta costos socials i econòmics. En aquest sentit, els mètodes no destructius (per exemple, ground penetrating radar - GPR) poden ser una resposta constructiva a aquests problemes, ja que permeten, com s'evidencia en aquesta tesi, per determinar rutes de canonades, identificar les característiques dels components, i detectar les fuites d'aigua quan encara no són significatives. La selecció del GPR en aquest treball es justifica per les seves característiques com a tècnica no destructiva que permet estudiar tant objectes metàl·lics i no metàl·lics. Tot i que la captura d'informació amb GPR sol ser reeixida, aspectes com ara la configuració de captura, el gran volum d'informació que es genera, i l'ús i la interpretació d'aquesta informació requereix alt nivell d'habilitat i experiència. Aquesta tesi pot ser vista com un pas endavant cap al desenvolupament d'eines capaces d'abordar el problema de la manca de coneixement sobre els actius d'aigua i sanejament enterrat. L'objectiu principal d'aquest treball doctoral és, doncs, generar eines i avaluar la seva factibilitat d'aplicació a la caracterització dels components de los SAAs, a partir d'imatges GPR. En aquest treball s'han dut a terme proves de laboratori específicament dissenyats per proposar, desenvolupar i avaluar mètodes per a la caracterització dels components d'aigua i sanejament soterrat. A més, hem dut a terme proves de camp, que ens han permès determinar la viabilitat de la implementació d'aquestes metodologies en condicions no controlades. Les metodologies desenvolupades es basen en tècniques d'anàlisi intel·ligent de dades. El principi bàsic d'aquest treball ha consistit en el tractament de dades obtingudes a través del GPR per buscar informació útil sobre els components d'SAA, amb especial èmfasi en la canonades. Després de realitzar nombroses activitats, es pot concloure que, amb l'ús d'imatges de GPR, és factible obtenir més informació que la identificació típica d'hipèrboles realitzat actualment. A més, aquesta informació pot ser observada directament, per exemple, més simplement, utilitzant les metodologies proposades en aquest treball doctoral. Aquestes metodologies també demostren que és factible per identificar patrons (especialment el pre-processat amb l'algoritme Agent race) que proporcionen bastant bona aproximació de la localització de fuites en SAAs. També, en el cas de tubs, es pot obtenir altres característiques com ara el diàmetre i el material. Els principals resultats d'aquesta tesi consisteixen en una sèrie d'eines que hem desenvolupat per localitzar, identificar i visualitzar els components dels SAAS a partir d'imatges GPR. El resultat més interessant és que els resultats obtinguts són sintetitzats i reduïts de manera que preserven les característiques dels diferents components registrats en les imatges de GPR. L'objectiu final és que les eines desenvolupades faciliten la presa de decisions en la gestió tècnica de SAA, i que tals eines poden fins i tot ser operades per personal amb poca experiència en el maneig de metodologies no destructives, específicament GPR.
Ayala Cabrera, D. (2015). Characterization of components of water supply systems from GPR images and tools of intelligent data analysis [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59235
TESIS
Premiado