Дисертації з теми "Collapse models"
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Ferialdi, Luca. "Non-Markovian collapse models." Doctoral thesis, Università degli studi di Trieste, 2010. http://hdl.handle.net/10077/3582.
Повний текст джерелаWe introduce the measurement problem in quantum mechanics and we briefly discuss the solutions proposed in literature. We then focus our attention on models of spontaneous wavefunction collapse. We describe the two most popular models (GRW, CSL) and list other proposals. We analyze in detail a third collapse model (QMUPL), which is particularly simple (but physically meaningful) to be studied in great mathematical detail. We discuss its main properties. We also describe a "finite temperature" version of this model, which includes dissipative terms. These models are Markovian, i.e. the collapse mechanism is driven by a white noise. Since the ultimate goal is to identify the noise responsible for the collapse with a random field in Nature, it becomes important to study non-Markovian generalizations of collapse models, where the collapsing field has a generic correlation function, likely with a cut off at high frequencies. Models of this kind have already been studied, as a generalization of the CSL model. In this thesis we describe in mathematical detail the generalization of the QMUPL model to non-Markovian noises. After having proved, under suitable conditions, the separation of the center-of-mass and relative motions for a generic ensemble of particles, we focus our analysis on the time evolution of the center of mass of an isolated system (free particle case). We compute the explicit expression of the Green's function via the path integral formalism, for a generic Gaussian noise. We analyze in detail the case of an exponential correlation function, providing the exact analytical solution. We next study the time evolution of average quantities, such as the mean position, momentum (which satisfy Ehrefest's theorem) and energy (which is not conserved like in the other collapse models). We also compute the non-Markovian master equation for an harmonic oscillator, according to this model, and compare its structure to the well-known Lindblad structure of Markovian open quantum systems. We eventually specialize to the case of Gaussian wave functions, and prove that all basic facts about collapse models (reduction process, amplification mechanism, etc.), which are known to be true in the white noise case, hold also in the more general case of non-Markovian dynamics. We further analyze the evolution of Gaussian wave function according to the three different realizations of the QMUPL model so far developed (Markovian, non-Markovian and "finite temperature"), comparing their fundamental features. Finally, by analyzing different localization criteria, we set new lower bounds on the parameters of these models, and we compare them with the upper bounds coming from known experimental data.
Nel primo capitolo si introduce il problema della misura in Meccanica Quantistica e si discutono brevemente le soluzioni proposte nella letteratura. Nel capitolo 2 si discutono i modelli di collasso spontaneo della funzione d'onda, con particolare attenzione per i modelli GRW e CSL; si elencano altri modelli. Si analizza in dettaglio anche il modello di riduzione QMUPL, il quale è particolarmente semplice (ma fisicamente significativo) da poter essere studiato dettagliatamente dal punto di vista matematico. Si discutono le sue proprietà principali. Si descrive inoltre una versione "a temperatura finita" di questo modello, che include termini dissipativi. Questi modelli sono Markoviani, ovvero il meccanismo di collasso è guidato da un rumore bianco. Poichè parte significativa della ricerca consiste nell'identificare il rumore responsabile del collasso con un campo stocastico esistente in Natura, diventa importante studiare le generalizzazioni non-Markoviane dei modelli di riduzione, in cui il campo di collasso ha una funzione di correlazione generale, probabilmente con un cutoff ad alte frequenze. Modelli di questo tipo, come la generalizzazione del modello CSL, sono già stati studiati. In questa tesi si descrive in dettaglio la generalizzazione a rumori non-Markoviani del modello QMUPL. Dopo aver provato, sotto particolari condizioni, la separazione del moto del centro di massa da quello relativo per un generico ensemble di particelle, si pone attenzione all'evoluzione temporale del centro di massa di un sistema isolato (particella libera). Si dà l'espressione esplicita per la funzione di Green attraverso il formalismo del path-integral, per un generico rumore Gaussiano. Si analizza in particolare il caso della funzione di correlazione esponenziale, fornendo la soluzione analitica esatta delle equazioni. Successivamente si studia l'evoluzione dei valori medi, in particolare della posizione, del momento (che soddsfa il teorema di Ehrenfest) e dell'energia (che non è conservata come negli altri modelli di riduzione). Si scrive inoltre la master equation non-Markoviana per un oscillatore armonico per questo modello, e si confronta la sua struttura con le ben nota struttura di Lindblad dei sistemi quantistici aperti Markoviani. Ci si specializza al caso di funzioni d'onda Gaussiane, e si prova che tutte le nozioni di base sui modelli di riduzione (processo di collasso, meccanismo di amplificazione, ecc.), che sono note essere vere nel caso Markoviano, valgono anche nel caso più generale di dinamiche non-Markoviane. Infine, si analizza l'evoluzione di funzioni d'onda Gaussiane secondo le tre differenti realizzazioni del modello QMUPL finora analizzate (Markoviana, non-Markoviana e "a temperatura finita"), confrontando le loro caratteristiche fondamentali. Inoltre, analizzando differenti criteri di localizzazione, si individano nuovi limiti inferiori per i parametri di questi modelli, e si confrontano con i limiti superiori che vengono da dati sperimentali noti.
XXII Ciclo
1982
Veal, Andrew Richard. "Models of polymer adsorption and collapse." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277107.
Повний текст джерелаAburihan, Mahmoud. "Time-dependent self-similar star formation and collapse models." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0002/MQ42578.pdf.
Повний текст джерелаDonadi, Sandro. "Electromagnetic Radiation Emission and Flavour Oscillations in Collapse Models." Doctoral thesis, Università degli studi di Trieste, 2014. http://hdl.handle.net/10077/9961.
Повний текст джерелаIn order to solve the measurement problem, collapse models modify the Schroedinger dynamics by adding non linear and stochastic terms. Collapse models provide different predictions compare to Quantum mechanics. In this thesis we focus on two phenomena where the predictions of quantum mechanics and collapse models are different: the electromagnetic radiation emission from charged systems and the flavour oscillations. We analysed both of them and obtained the quantitative deviations from standard quantum behaviour.
Al fine di risolvere il problema della misura, i modelli di collasso spontaneo della funzione d'onda modificano la dinamica data dall'equazione di Schroedinger aggiungendo termini non lineari e stocastici. I modelli di collasso forniscono previsioni differenti rispetto alla meccanica quantistica. In questa tesi studieremo due fenomeni dove le predizioni della meccanica quantistica e dei modelli di collasso sono diverse: l'emissione di radiazione elettromagnetica da sistemi elettricamente non neutri e le oscillazioni dei sapori. Analizzeremo entrambi i fenomeni al fine di ottenere deviazioni quantitative dal comportamento quantistico standard.
XXVI Ciclo
1985
Orifici, Adrian Cirino, and adrian orifici@student rmit edu au. "Degradation Models for the Collapse Analysis of Composite Aerospace Structures." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080619.090039.
Повний текст джерелаClark, Paul Campbell. "The onset of gravitational collapse in molecular clouds." Thesis, University of St Andrews, 2005. http://hdl.handle.net/10023/12945.
Повний текст джерелаGaudreault, Mathieu. "Collapse transition of SARWs with hydrophobic interaction on a two dimensional lattice." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112623.
Повний текст джерелаWebster, Mort David, Jeffery Scott, Andrei P. Sokolov, and Peter H. Stone. "Estimating Probability Distributions from Complex Models with Bifurcations: The Case of Ocean Circulation Collapse." MIT Joint Program on the Science and Policy of Global Change, 2006. http://hdl.handle.net/1721.1/32540.
Повний текст джерелаAbstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).
This research was supported in part by the Methods and Models for Integrated Assessments Program of the National Science Foundation, Grant ATM-9909139, by the Office of Science (BER), U.S. Department of Energy, Grant Nos. DE-FG02-02ER63468 and DE-FG02-93ER61677, and by the MIT Joint Program on the Science and Policy of Global Change (JPSPGC).
Harry, Ofonime Akpan. "Behaviour of reinforced concrete frame structure against progressive collapse." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/29623.
Повний текст джерелаReyes, Juan Daniel Bojowald Martin. "Spherically symmetric loop quantum gravity connections to two-dimensional models and applications to gravitational collapse /." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4758/index.html.
Повний текст джерелаBamber, Nicholas Peter. "The real-collapse : initial segments of models of arithmetic and the construction of the reals." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386097.
Повний текст джерелаGeyer, Traver Adelina. "Dynamics and structural evolution of collapse calderas: A comparison between field evidence, analogue and mathematical models." Doctoral thesis, Universitat de Barcelona, 2007. http://hdl.handle.net/10803/1921.
Повний текст джерелаAfter several pioneering works, collapse calderas have been the subject of studies of diverse disciplines. However, some important aspects on caldera dynamics and structure remain poorly understood yet.
First, we have revised important works concerning field data about collapse calderas and summarized the most relevant aspects and results. We have created a database to record existing information about collapse calderas: Collapse Caldera DataBase (CCDB). After an exhaustive analysis of the included information we have observed two types of collapse caldera: type-A and type-B.
Experiments on caldera collapse modelling allow a qualitative study of the structural evolution of a caldera collapse process and suggest which of factors play a more relevant role. Analogue models have verified that caldera collapse formation is influenced by multiple aspects (e.g. regional tectonics). We have performed three types of semi-quantitative analyses of particular interest for volcanic hazard: the measurement of the erupted magma chamber volume fraction required to achieve each step of the collapse process, the estimation of the subsidence pattern and the study of the influence of the roof aspect ratio in the dimensions of the collapse parts at surface.
This work includes also a summary of the most important aspects concerning mathematical models of collapse calderas. In base of a mathematical analysis of the pressure evolution inside the chamber during volcanic cycles, we have defined two collapse caldera end-members: under- and overpressure calderas. We have (1) reproduced numerically some of the analogue experiments set out in this work; (2) studied the influence of the selected geometrical setting (e.g. axial symmetric or three-dimensional) in the obtained results and subsequent interpretations and (3) demonstrated that results obtained with mathematical models not strictly related to collapse caldera processes are also applicable to the study of collapse mechanisms and controlling factors.
Finally, we compare the different results obtained by the three distinct disciplines, in order to propose a genetic classification for collapse calderas and to describe the dynamic and structural evolution of the defined end-members. We distinguish between "Cordilleran type" and "Composite volcano type" calderas. Calderas related to the first group correspond to commonly rhyolitic or dacitic, large plate/piston or trap-door calderas formed from a sill-like overpressurized magma chamber in the presence of a regional extensive stress field and a large scale doming or underplating. These calderas tend to occur in areas of thick or thin continental crust and in evolved transitional thick crust. They are associated with C-type subduction zones and areas of continental rifting. "Composite volcano type" calderas occur at the culmination of a long eruptive cycle in composite volcanoes. They take place at the summit of a long-lived volcanic edifice, which has undergone various periods of magma chamber inflation and deflation and different eruptions. The caldera-forming eruption begins with overpressure inside the chamber that triggers, once overcome the tensile strength of the host rock, magma injection into the host rock and finally, an eruption. Calderas included in this group tend to be smaller and not too voluminous.
Concluding, the combination of field studies with experimental and theoretical/mathematical and modelling allows us to identify and quantify the main factors controlling collapse calderas.
Araujo, Robyn Patrice. "Mathematical modelling of mechanical stresses and vascular collapse in solid tumours." Thesis, Queensland University of Technology, 2003. https://eprints.qut.edu.au/37156/6/37156_Digitised_Thesis.pdf.
Повний текст джерелаSong, Brian Inhyok. "EXPERIMENTAL AND ANALYTICAL ASSESSMENT ON THE PROGRESSIVE COLLAPSE POTENTIAL OF EXISTING BUILDINGS." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281712538.
Повний текст джерелаGardell, Jens. "Benchmark of RELAP5 Check Valve Models against Experimental Data." Thesis, Linköpings universitet, Mekanisk värmeteori och strömningslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-103609.
Повний текст джерелаQin, Wenyi. "Many server queueing models with heterogeneous servers and parameter uncertainty with customer contact centre applications." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33167.
Повний текст джерелаCornacchia, Francesco. "Theoretical and numerical models of innovative cross-sections for flexible pipelines in research and design." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Знайти повний текст джерелаStockinger, Georg [Verfasser], Hans-Thomas [Akademischer Betreuer] Janka, Sherry [Gutachter] Suyu, and Hans-Thomas [Gutachter] Janka. "Three-dimensional Models of Core-collapse Supernovae From Low-mass Progenitors / Georg Stockinger ; Gutachter: Sherry Suyu, Hans-Thomas Janka ; Betreuer: Hans-Thomas Janka." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/121624247X/34.
Повний текст джерелаASCHONITIS, Vasileios. "Assessment of European eel (Anguilla anguilla L.) population dynamics in the Comacchio lagoon using mathematical models and the role of global factors in population collapse." Doctoral thesis, Università degli studi di Ferrara, 2016. http://hdl.handle.net/11392/2403387.
Повний текст джерелаThe European eel (Anguilla anguilla L.) is a catadromous and semelparous species that spends most of its life in fresh water, brackish and coastal habitats (yellow eel stage). When reaching maturity passes to the silver eel stage and migrates to the Sargasso Sea (Atlantic Ocean) in order to spawn and die. The larvae (leptocephalus) drift back using oceanic currents and metamorphose into transparent glass eels when they reach the European coastlines. Records of juvenile stocks indicate a tremendous decline during the last four decades not only for A.anguilla but also for other important eel species like the American eel (Anguilla rostrata L.) and the Japanese eel (Anguilla japonica T. & S.). The eel fishery in the Comacchio Lagoon (Italy), which is one of the oldest organized eel fisheries in the world, also faces large stock decline. Taking into account data about A.anguilla in Comacchio from older surveys and surveys performed during 2011-2012 and other information from the international literature, the following objectives were set in the context of the thesis: a) Development of new length-weight (LWR) and length-age (LAR) relationships of A.anguilla from the Comacchio Lagoon using data of 2011 and comparison with previous surveys. b) A size-age model development based on bootstrapping and Bayesian approaches for the assessment of eel population dynamics in semi-closed lagoons and application of the model for the Comacchio population. c) Analysis of the long-term series of A.anguilla production in the Comacchio and conducting a literature review and analysis about the contribution of local and global stressors on the population collapse. d) The major part of the thesis deals with mathematical models related to eel population dynamics and morphometric characteristics. Such models consist of many bi-variate functions which describe isolated attributes of the populations. For this reason, a supplementary theoretical chapter was included in the thesis and concerns the literature review and synthesis of various types of such functions which can be used in ecological, biological and environmental problems. The results of the thesis showed that the eel stock of Comacchio has undergone 99% feminization, probably due to the population density reduction. The analysis of LWR showed that it was not affected by the reduction of population density and approximates the estimated ones of the late seventies before population collapse. On the other hand, LAR was affected leading to age classes reduction and consequently faster maturation rates (younger, longer and heavier silver eels before their migration). The size-age model was calibrated using the data of 2011 and assessed the survival curve, stock, recruitment and metamorphosis rates (from yellow to silver) of Comacchio population. The model was successfully validated using data from 2012. The modeling approach included a method for correcting errors inserted by net selectivity while a new bi-variate function for estimating survival curve was also incorporated. A bootstrap procedure was used to assess the level of uncertainty for each model parameter using the 95% intervals of the highest posterior density distribution (Bayesian approach). The estimated stocks and recruitment by the model were at least ten times lower from the respective estimations of previous studies using data from the late 80s highlighting the crucial state of the population. The data for the silver eel production from Comacchio Lagoon (equivalent to the total migrating population) cover the period 1781-2013 and constitute the longest annual records in the world about the fishery of the specific fish species. The data include information related to habitat loss and other local stressors of the population (e.g. frost, hypersalinity, floods, pollution events etc). The role of the local stressors on the decline of the local stock was investigated while additional information from the literature was also used to discuss the effects of global stressors (e.g. glass eel harvest for aquaculture, climate-oceanographic changes, habitat loss, pollution and parasitism) on the three eel species A.anguilla, A.japonica, A.rostrata. The population collapse in Comacchio, which started in the ‘70s with no signs of recovery, could not be explained by local stressors. The literature about the global stressors suggested that the three eel species are under a combined threat from various directions. Aquaculture, which depends entirely on wild-caught glass eels, was found to play a key role in the decline of natural stocks. The correlations between European aquaculture production versus the Comacchio yields and other published data from other European eel and glass eel fisheries were found significantly high exposing the crucial role of aquaculture. Conservative estimations using FAO data showed that the current amount of glass eels needed to support aquaculture production in Europe and Asia exceeds the 2×109 specimens. This demand, largely covered by A. anguilla glass eel, can justify eel populations decline since glass eel trade has been expanded at international level. The supplementary theoretical study provided a total of 20 models which can describe symmetric and non symmetric bell-shaped curves, convex and simple sigmoid curves (saturation-growth type), double sigmoid curves (saturation-growth type), bilinear and periodical curves. The models were also modified in order to describe the relative variation of a dependent variable (range of dependent variable between 0-1). Additional guidelines were also provided on how to create a mirror curve based on each one of the aforementioned 20 models.
Ding, Yao. "Evaluation of New Seismic Performance Factors for Special Hybrid Coupled Core Wall Systems with Steel Coupling Beams." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1573225104906633.
Повний текст джерелаHerbauts, Isabelle Manon. "Causal wave function collapse model." Thesis, Queen Mary, University of London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427988.
Повний текст джерелаDavies, Guilherme Izidório. "Análise e modelagem do comportamento colapsível de um solo arenoso." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-25062018-135932/.
Повний текст джерелаThere are many researches that evaluate and discuss the factors which interfere in the collapse of soils. However, not many have been published regarding the influence of the cycles of wetting in the collapsible behavior of the soil, and neither have collapse strains under triaxial load. The present work deals with the collapse behavior of a sandy soil, typical from the center-west of the State of São Paulo, considering the aforesaid aspects and using conventional oedometer, suction controlled oedometer and triaxial compression tests. In conventional oedometer tests, the influence of overburden stress on the induced wetting on collapse strains was characterized. Collapse strains were also measured in triaxial compression tests, varying the ratio of principal stress (▟/□) when the samples are inundated. It was observed that collapse volumetric strains are dependent on confining stress and on ▟/□, and that, axial and radial strains are related to the ratio of ▟/□. The axial collapse strains observed in triaxial compression tests were shown to be lower than the ones measured in conventional oedometer tests. In controlled suction tests, the amount of collapse strains under gradual suction reduction was studied including the influence of suction reversals. It was noted that the initial suction influences the amount of collapse strains, and that, in the cycles of wetting and drying, the strains after the second cycle tended to be negligible. Experimental results from suction controlled oedometer tests were modeled through the model by ALONSO et. al. (1990) and by the adaptations to this model proposed by FUTAI (1997) and MACHADO (1998).
Plunkett, J. William (James William Jr ). "The Roman Pantheon : scale-model collapse analyses." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107867.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 27-31).
The Roman Pantheon is among the largest unreinforced masonry dome ever built and is an unparalleled example of the construction capabilities of the ancient Romans. As one of the most well-known buildings in the world, its preservation remains important because of its cultural and societal significance, and the methods used to assess the safety of historic masonry structures continue to be developed, particularly for three-dimensional vaulted forms. Through a study of the Roman Pantheon, this thesis compares analytical and experimental results on a 1:100 scale model of the variable thickness, hemispherical dome. The model is created using additive manufacturing for accuracy. This thesis, using a physical scale model, quantifies the safety of the Roman Pantheon against the two most probable causes of collapse (i) deformation of the building geometry and (2) seismic activity. The structural behavior of the model is compared to analytical predictions of (1) spreading supports, simulating leaning walls that result from the dome thrust or settling of the foundations, and (2) tilting, a first-order approximation of horizontal ground acceleration. The experimental tests lead to the formation of a mechanism and collapse due to instability. High-speed imagery captures the observed collapse mechanisms and failure limits. Experimental results are compared to analytical predictions for hemispherical masonry domes. The results of the physical experiment demonstrate the potential for digitally fabricated scale models in approximating the behavior of three-dimensional structures with complex geometries. The low cost and rapid approach provides a useful method for validating analytical predictions of the limit states and collapse mechanisms of unreinforced masonry structures.
by J. William Plunkett.
S.M. in Building Technology
Goda, Ibrahim. "Micromechanical models of network materials presenting internal length scales : applications to trabecular bone under stable and evolutive conditions." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0055/document.
Повний текст джерелаA methodology based on micromechanics has been developed to determine the effective behavior of network materials endowed with a discrete architecture at the microscopic level. It relies on the discrete homogenization method, which has been applied to textile monolayers and trabecular bones. The initially discrete topology of the considered network materials results after homogenization at the mesoscopic level in anisotropic micropolar effective continuum, which proves able to capture the observed internal scale effects. Such micromechanical methods are useful to remedy the difficulty to measure the effective mechanical properties at the intermediate mesoscopic level scale. The bending and torsion responses of vertebral trabecular bone beam specimens are formulated in both static and dynamic situations, based on the Cosserat theory. 3D models have been developed for describing the multiaxial yield and brittle fracture behavior of trabecular bone, including the analysis of size-dependent non-classical plastic yield. We have constructed by FE analyses a homogeneous, orthotropic couple-stress continuum model as a substitute of the 3D periodic heterogeneous cellular solid model of vertebral trabecular bone, based on the equivalent strain energy approach. Bone tissues are able to adapt their local density and load bearing capacities as well as their size and shape to mechanical stimuli. We have developed models for combined internal and external bone remodeling in the framework of the thermodynamics of irreversible processes, at both the cellular and macroscopic levels. We lastly combined anisotropic internal remodeling with fatigue continuum damage
Eid, Nicolas. "Contribution méthodologique à l'étude in vitro des modes de dégradation des interfaces collées." Paris 5, 1996. http://www.theses.fr/1996PA05M119.
Повний текст джерелаNassiri, Esmail. "Modelling nonlinear behaviour of two-dimensional steel structures subjected to cyclic loading." Thesis, Queensland University of Technology, 1998.
Знайти повний текст джерелаAngeles, Antolin Linan Maria. "Effects of load modelling on Voltage Impasse Regions (VIR)." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254416.
Повний текст джерелаVIR (Voltage Impasse Regions) är ett fenomen i kraftsystem varsdynamiska förlöp beskrivs av differential-algebraiska ekvationer(DAE). VIR betecknar ett område i tillståndsrummet där går förlorad,dvs Jakobianen av den algebraiska delen av DAE är singulärI tidsdomän-simuleringar (TDS) när en trajektoria träffar VIR,konvergerar TDS inte till en lösning. Då finns ingen anledning attfortsätta med simuleringen. Därför är det viktigt att förstå mekanismernasom introducerar VIR. Det är känt att VIR är relateradetill statiska, icke-linjära lastmodeller. Det var dock okänt vadden kumulativa effekten av flera statiska, icke-linjära belastningarskulle vara.Denna uppsats har vidareutvecklat begreppet VIR genom attgenomföra en strukturerad studie om hur lastmodellering påverkarVIR. För detta ändamål föreslår denna avhandling en kvasidynamiskmetod för att kartlägga VIR i det relativa rotorvinkelrummet.Metoden introducerar ett nytt diskret index som heterVoltage Impasse Region Flag (VIRflag), vilket gör det möjligt attbestämma om den algebraiska delen av DAE är lösbar eller inteoch därmed lokalisera VIR. Ett används för att testa det föreslagnakvasi-dynamiska tillvägagångssättet. VIRflag användes först för attkartlägga VIR för olika belastningskombinationer. Därefter granskasförhållandet mellan konvergensproblem i TDS och korsningenmellan en trajektoria och VIR för att verifiera den föreslagna metoden.Den föreslagna metoden har visat sig vara effektiv vid bestämningav VIR, oberoende av antalet icke-linjära belastningar. Bland destatiska exponentiella belastningsmodellerna har konstanteffektlast(CP) haridentifierats som den som har störst inflytande påVIR;s form. Den konstantströmlasten (CC) inducerar mindre"VIRområdenoch konstantimpedanslasten (CI) kan endast ändra formenav VIR i närvaro av icke-linjära belastningsmodeller.
Morone, Daniel Justin Reese. "Progressive Collapse: Simplified Analysis Using Experimental Data." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354602937.
Повний текст джерелаWang, Joseph Chen-yu. "A one dimensional model of convection in iron core collapse supernovae /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Повний текст джерелаMonasterios, Perez Karin. "Structural adjustment and the collapse of the Bolivian model of accumulation." Ottawa, 1994.
Знайти повний текст джерелаAkah, Ebiji Anthony. "Experimental and Analytical Collapse Evaluation of an Existing Building." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437620552.
Повний текст джерелаVernier, Eric. "Non compact conformal field theories in statistical mechanics." Thesis, Paris, Ecole normale supérieure, 2015. http://www.theses.fr/2015ENSU0005/document.
Повний текст джерелаThe critical points of statistical mechanical systems in 2 dimensions or quantum mechanical systems in 1+1 dimensions (this also includes non interacting systems in 2+1 dimensions) are effciently tackled by the exact methods of conformal fieldtheory (CFT) and integrability, which have witnessed a spectacular progress during the past 40 years. Several problems have however escaped an exact understanding so far, among which the plateau transition in the Integer Quantum Hall Effect,the main reason for this being that such problems are usually associated with non unitary, logarithmic conformal field theories, the tentative classification of which leading to formidable mathematical dificulties. Turning to a lattice approach, andin particular to the quest for integrable, exactly sovable representatives of these problems, one hits the second dificulty that the associated CFTs are usually of the non compact type, or in other terms that they involve a continuum of criticalexponents. The connection between non compact field theories and lattice models or spin chains is indeed not very clear, and in particular it has long been believed that the former could not arise as the continuum limit of discrete models built out of acompact set of degrees of freedom, which are the only ones allowing for a systematic construction of exact solutions.In this thesis, we show that the world of compact lattice models/spin chains with a non compact continuum limit is much bigger than what could be expected from the few particular examples known up to this date. More precisely we propose an exact Bethe ansatz solution of an infinite family of models (the so-called $a_n^{(2)}$ models, as well as some results on the $b_n^{(1)}$ models), and show that all of these models allow for a regime described by a non compact CFT. Such models include cases ofgreat physical relevance, among which a model for two-dimensional polymers with attractive interactions and loop models involved in the description of coupled Potts models or in a tentative description of the quantum Hall plateau transition by somecompact geometrical truncation. We show that the existence of an unsuspected non compact continuum limit for such models can have dramatic practical effects, for instance on the output of numerical determination of the critical exponents or ofMonte-Carlo simulations. We put our results to use for a better understanding of the controversial theta transition describing the collapse of polymers in two dimensions, and draw perspectives on a possible understanding of the quantum Hall plateautransition by the lattice approach
Christenson, Michael P. "Black Spaghetti: A Numerical Model of Gravitational Collapse in 4 + 1 Spacetime." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd907.pdf.
Повний текст джерелаVandamme, Johan Richard. "Novel particle model for the prediction of stability and episodic collapse of coastal cliffs and levees." Thesis, University of Plymouth, 2012. http://hdl.handle.net/10026.1/1027.
Повний текст джерелаCorral, Jofré Gonzalo Andrés. "Re-analysis of deep excavation collapse using a generalized effective stress soil model." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/60759.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 137-138).
This thesis re-analyzes the well-documented failure of a 30m deep braced excavation underconsolidated marine clay. Prior analyses of the collapse of the Nicoll Highway have relied on simplified soil models with undrained strength parameters based on empirical correlations and piezocone penetration data. In contrast, the current research simulates the engineering properties of the key Upper and Lower Marine Clay units using a generalized effective stress soil model, MIT-E3, with input parameters calibrated using laboratory test data obtained as part of the post-failure site investigation. The model predictions are evaluated through comparisons with monitoring data and through comparisons with results of prior analyses using the Mohr-Coulomb (MC) model. The MIT-E3 analyses provide a modest improvement in predictions of the measured wall deflections compared to prior MC calculations and give a consistent explanation of the bending failure in the south diaphragm wall and the overloading of the strut-waler connection at the 9th level of strutting. The current analyses do not resolve uncertainties associated with performance of the JGP rafts, movements at the toe of the north-side diaphragm wall or discrepancies with the measured strut loads at level 9. However, they represent a significant advance in predicting excavation performance based directly on results of laboratory tests compared to prior analyses that used generic (i.e., non site-specific) design isotropic strength profiles.
by Gonzalo Andrés Corral Jofré.
Civ.E.
Gambarotto, Pietro. "Formation of dark matter halos. Statistics and dynamics of the ellipsoidal collapse model." Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3424900.
Повний текст джерелаNel quadro del modello cosmologico standard, la formazione delle strutture è descritta attraverso il collasso di perturbazioni di densità con una distribuzione iniziale generalmente assunta come gaussiana. Queste fluttuazioni erano inizialmente piccole e sono cresciute successivamente per effetto della gravità. In un universo ΛCDM la formazione delle strutture cosmiche è guidata dal collasso della materia oscura che porta alla formazione di aloni virializzati. La materia barionica cade dentro alle buche di potenziale create da questi aloni, si raffredda e conduce alla formazione di stelle e galassie, trasformando la sua energia cinetica in energia termica (White and Rees 1978; Blumenthal et al. 1984). Successivamente, le strutture crescono in modo gerarchico, dalle più piccole alle più grandi. Quindi, aloni contenenti galassie massicce si formano tramite l’accrescimento di aloni più piccoli da parte dell’alone principale. Il collasso e la successiva formazione di aloni di materia oscura è dovuto unicamente alla gravità; per questo motivo la sua descrizione è semplice in linea di principio e coinvolge un alto numero di particelle. Un modo efficace di analizzare la formazione di questi aloni passa per l’utilizzo di simulazioni a N corpi. Con questo approccio non si ricerca una soluzione analitica, bensì viene fatto evolvere un gran numero di particelle soggette alla sola interazione gravitazionale. È così possibile simulare una regione di universo e analizzare il moto delle particelle e la formazione di strutture collassate. La struttura di questo lavoro è la seguente: • Capitolo 1: Presentiamo il modello cosmologico standard per la formazione delle strutture cosmiche e descriviamo brevemente le proprietà statistiche dei campi di fluttuazionelinearielacrescitadiperturbazionilineariallalucedellateoriadiJeans. • Capitolo 2: Descriviamo i principali approcci analitici allo studio delle perturbazioni in regime non lineare. Prima di tutto presentiamo l’approssimazione di Zel’dovich applicabile al caso di un regime quasi lineare. e descriviamo i due principali modelli dinamici per lo studio del collasso delle strutture: il modello di collasso sferico e il modello di collasso ellissoidale. Più avanti descriviamo due approcci analitici per la determinazione la statistica degli aloni a partire dal campo di fluttuazioni iniziale: il modello degli excursion sets e il formalismo dei picchi. Descriviamo anche brevemente alcuni tentativi di fondere assieme questi due approcci. • Capitolo 3: Descriviamo il metodo principale utilizzato per lo studio di strutture fortemente non lineari: le simulazioni a N corpi. Descriviamo inoltre le caratteristiche principali delle simulazioni numeriche utilizzate in questo lavoro. Infine, descriviamo le proprietà principali degli aloni di materia oscura, concentrandoci sul contributo dato a questo campo dalle simulazioni numeriche. • Capitolo 4: Inizialmente descriviamo i diversi metodi per l’identificazione di aloni e i criteri di rilassamento usati in questo lavoro. Successivamente descriviamo come sono stati calcolati i parametri del collasso ellissoidale a partire dagli autovalori del tensore di deformazione smussati su diverse scale. L'ultima sezione del capitolo è infine dedicata allo studio di una descrizione della distribuzione dei tempi di formazione dei soli aloni rilassati. • Capitolo 5: Descriviamo il metodo usato per l’identificazione dei picchi nei campi iniziali e presentiamo una descrizione statistica dei picchi suddetti. Successivamente analizziamo la funzione di correlazione tra i centri di massa dei protoaloni e i picchi e le valli nella distribuzione dei parametri di interesse. L'ultima parte del capitolo è dedicata all'analisi di un’alternativa al formalismo dei picchi per l’identificazione della formazione degli aloni. Infatti, il collasso sferico e quello ellissoidale mancano di un termine di dipolo presente invece nella teoria delle perturbazioni. Studiamo dunque i punti dove il dipolo iniziale svanisce e li relazioniamo ai centri di massa dei protoaloni. • Capitolo 6: Nella prima parte presentiamo una descrizione statistica dei parametri Lagrangiani, svolgendo un opportuno confronto coi risultati di altri autori. Successivamente indaghiamo la correlazione tra i parametri lagrangiani δL e qL e i redshift di formazione degli aloni z50 in funzione della massa universale ν e del redshift di identificazione. • Capitolo 7:Mentre nel precedente capitolo abbiamo descritto parametri smussati su una sola scala, la scala lagrangiana degli aloni, passiamo ora all’analisi dei profili. Primariamente costruiamo i profili lagrangiani attorno al centro di massa dei protoaloni e mostriamo come correlano con il parametro di shear e il redshift di formazione. Successivamente studiamo la relazione tra i profili lagrangiani e i profili euleriani e mostriamo che l’effetto dello shear lagrangiano e del tempo di formazione ancora presente nei profili finali. Infine studiamo l’evoluzione dei profili delle particelle dell’alone a diversi tempi cosmici.
Zuccon, Alexandre. "Análise do ligamento redondo na instabilidade não traumática do quadril estudo experimental em coelhos /." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153010.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Introdução: A luxação do quadril em uma criança pode interferir com a função dessa articulação, causando dor, limitação de movimento, entre outras consequências. Na redução aberta da articulação, diversas estruturas anatômicas são abordadas como o ligamento redondo (LR) que, tradicionalmente, é ressecado. Porém, existe controvérsia a respeito de sua importância funcional. Objetivo: Comparar através de análise biomecânica, bioquímica e histológica o LR de quadris instáveis (luxados e subluxados) com o ligamento de quadris normais. Métodos: Estudo experimental com coelhos esqueleticamente imaturos, utilizando um modelo para luxação do quadril. Oitenta e oito coelhos foram submetidos à fixação do joelho de uma das patas traseiras em extensão, o que leva à instabilidade do quadril ipsilateral, devido ao desequilíbrio muscular e à alteração em posicionamento no membro. Dezenove coelhos morreram, 28 foram excluídos por não evoluírem com a luxação e 5 foram excluídos pela impossibilidade de identificação do LR. Dos 36 coelhos que compuseram a amostra, estratificamos as análises em quantitativas: biomecânica (12 coelhos), zimografia (8 coelhos), histologia (14 coelhos) e qualitativa: imuno-histoquímica (2 coelhos). Realizamos análise estatística para comparação entre o lado luxado e o controle de cada coelho quanto às análises quantitativas. Resultados: No ensaio biomecânico, a média da força máxima do ligamento redondo no lado luxado foi de 43,25 ± 16,25N e 46,62 ± 15,56N para o lado normal (p=0,594) e a média da deformação máxima foi de 3,94 ± 1,88mm para o lado luxado e 4,55 ± 1,19mm para o normal (p = 0,328). Histologicamente foi quantificada a celularidade, mostrando em média, para o ligamento do lado luxado, 6,83 ± 3,47 células por campo e 3,87 ± 2,13 para o lado normal (p<0,001), além de 74,3 ± 10,5% de ocupação por colágeno no lado luxado e 84,5 ± 9,5% no lado normal (p<0,001). Na zimografia, a quantidade de metaloproteinase 2 (MMP2) em forma ativa foi 481,8 ± 228UA, em média, para o lado luxado e de 294,4 ± 78UA para o lado normal (p=0,068). Conclusão: Embora tenham ocorrido alterações significativas no LR dos quadris instáveis do ponto de vista histológico e com diferença importante na zimografia, esta sem significância estatística, isso não foi observado no ensaio biomecânico, no qual não houve diferença estatística entre os lados.
In the open reduction, used in the treatment of the hip dislocation in children, several structures are approached, such as the round ligament (RL) that has traditionally been resected. However, there is controversy regarding its possible maintenance as well as its functional importance. The aim of this study was to compare the RL properties of stable and unstable hips. Methods: Experimental study with young rabbits using a model for congenital hip dislocation. Eighty-eight rabbits underwent fixation of the knee of one hind leg in extension, which leads to ipsilateral hip instability. Nineteen rabbits died and 28 were excluded because they did not develop dislocation. Five additional rabbits also excluded because they did not present the RL. Thirty-six rabbits composed the sample that was stratified for quantitative analysis: biomechanical (12 rabbits), zymography (8 rabbits), histology (14 rabbits) and qualitative: immunohistochemistry (2 rabbits). We performed statistical analysis for comparison between the unstable side and the control of each rabbit. Results: Biomechanical assay showed the mean maximal strength of the RL on the unstable side was 43.25 ± 16,25N and 46.62 ± 15,56N for the control side (p = 0.594) and the mean maximum deformation was 3.94 ± 1,88mm for the unstable side and 4.55 ± 1,19mm for the control (p = 0.328). Histologically, there was an increase in cellularity on the unstable side showing, on average, 6.83 ± 3,47 cells per field and 3.87 ± 2,13 for the control side (p <0.001), in addition to 74.3 ± 10,5% of collagen occupancy on the unstable side and 84, 5 ± 9,5% on the control side (p <0.001). In zymography, the amount of metalloproteinase 2 (MMP-2) was 481.8 ± 228UA, on average, for the unstable side and 294.4 ± 78UA for the control side (p = 0.068). Conclusions: Although there were significant changes in the RL of the unstable hips from the histological analysis and there were an important diference in zymography without statistical significance, that was not observed in the biomechanical test.
Schulz, Roman. "Algoritmy pro zjednodušování modelů." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235967.
Повний текст джерелаHupka, Dušan. "Techniky "level of detail" v knihovně OpenSceneGraph." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2014. http://www.nusl.cz/ntk/nusl-236099.
Повний текст джерелаAlpsten, Freja. "Investigation of a Collapsed Cone Superposition Algorithm for dosimetry in brachytherapy." Thesis, Stockholms universitet, Fysikum, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-195490.
Повний текст джерелаMuñoz, Méndez María Elena. "El lugar del modelo y el modelo de lo puro — de Cézanne al collage." Tesis, Universidad de Chile, 2010. http://www.repositorio.uchile.cl/handle/2250/101265.
Повний текст джерелаLo, Reuben Bing Quan. "A multidisciplinary engineering geological investigation of cliff collapse at Redcliffs in the 22nd February and 13 June 2011 earthquakes." Thesis, University of Canterbury. Geological Sciences, 2013. http://hdl.handle.net/10092/8733.
Повний текст джерелаHicks, Peter Daniel. "A thermodynamic model of rainwater and magmatic vapour flow in a porous medium : triggering of a volcanic lava dome collapse." Thesis, University of East Anglia, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445213.
Повний текст джерелаZorzi, Luca. "From Deep Seated Gravitational Movements to Rock Avalanches: the role of failure mechanism in sudden rock collapse." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3423128.
Повний текст джерелаQuesto progetto di ricerca ha come focus la comprensione dei meccanismi di deformazione e di collasso (dall'innesco alla prpagazione della rottura) che governano Deformazioni Gravitative Profonde di Versante (DGPV) e valanghe di roccia (rock avalanches) in versanti rocciosi. In particolare, l'attenzione primaria di questo lavoro è indirizzata ai meccanismi di propagazione della rottura, alla loro influenza sulla stabilità dei versanti ed alle dinamiche del collasso. Lo scopo principale è migliorare le conoscenze ed i modelli relativi ai meccanismi di fratturazione e di rottura progressiva in ammassi rocciosi foliati, attraverso un approccio multidisciplinare che prevede l'analisi delversante con tecniche geologico - strutturali, geomorfologhiche, geomeccaniche e di modellazione numerica. Cause innascanti e meccanismi di rottura progressiva sono stati analizzati prendendo come caso studio un collasso gravitativo di grandi dimensioni nelle Alpi orientali (la rock avalanche della Val Ridanna). Il versante sinistro della Val Ridanna (Sterzing/Vipiten, Alto Adige, Italia), collocato geologicamente nelle unità cristalline della falda Austroalpina del prisma orogenetico delle Alpi, mostra evidenze un'evoluzione gravitativa quaternaria di tipo differenziale, la quale è fortemente controllata dall'assetto geologico duttile/fragile delle unità metamorfiche costituenti il versante. Indagini di terreno, unita ad una dettagliata analisi del modello digitale del terreno ottenuti da acquisizioni LiDAR, ha permesso di riconoscere differenti deformazioni gravitative all'interno del versante studio. La parte centarle della valle è caratterizzata da un evidente accumulo derivante da un collasso gravitativo di tipo rock avalanche; lungo il verante, ad ovest ed ad est dell'area sorgente della rock avalanche, due DGPV, riconosciute per la prima volta grazie a questo lavoro, coinvolgono il versante. Il presente lavoro mostra come l'assetto duttile/fragile agisca da un lato come fattore predisponente alle deformazioni gravitative riconosciute; dall'altro controlla direttamente le modalità evolutive delle deformazioni stesse. Si ritiene che i risultati ottenuti da questa tesi di dottorato possano contribuire al miglioramento delle conoscenze sull'evoluzione di DGPV in rocce metamorfiche polideformate, in particolare per quanto concerne i meccanicsmi che governano l'evoluzione parossistica di un ammasso roccioso in deformazione lenta.
Brezzi, Lorenzo. "Calibration strategies of a depth-integrated numerical model for the propagation of flow-like landslides." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3421799.
Повний текст джерелаOggigiorno, i modelli numerici ricoprono un ruolo di fondamentale importanza per lo studio di fenomeni fisici e naturali. Essi diventano via via sempre più complessi grazie all’aumento del numero di equazioni differenziali implementate in ciascun modello al fine di tener conto dei differenti aspetti che caratterizzano il fenomeno oggetto studio. Conseguentemente cresce anche il numero dei parametri da valutare per adattare i risultati ottenuti dal modello numerico alle misure reali. Tra tutti i fenomeni naturali che si possono considerare, i frane sono indiscutibilmente molto importanti. Tra i diversi tipi di frane, le colate sono una tipologia che si presenta sempre con maggior frequenza a causa dei cambiamenti climatici in atto e con effetti molto dannosi. Quando, poi, la velocità raggiunta in questi fenomeni diventa elevata, aumenta il loro potere distruttivo. I rischi e i danni che ne possono nascere non sono trascurabili, in modo particolare quando le colate avviene in prossimità di aree residenziali. Gli effetti catastrofici che ne possono scaturire spaziano dalla distruzione di edifici e infrastrutture, fino ad arrivare alla ancor più tragica perdita di vite umane. Quando si studia un movimento di colata, tre processi devono essere presi in considerazione: il meccanismo di innesco, la fase di propagazione ed infine il deposito. Questa tesi riguarda principalmente lo studio degli ultimi due processi che si verificano, cioè, quando il materiale ha già iniziato il suo movimento. Le fasi di propagazione e di arresto sono qui analizzate utilizzando un modello numerico sviluppato integrando le equazioni di Saint Venant per il flusso di un materiale monofase omogeneo in acque basse. Il modello è stato applicato sia per la simulazione di esperimenti di laboratorio sia per riprodurre un debris flow avvenuto nel nord Italia nel 2010. Quando si utilizza un modello numerico, la fase di calibrazione rappresenta un’operazione essenziale affinché si possano ottenere buoni risultati. I parametri utilizzati dal codice devono essere attentamente definiti in modo che il modello possa riprodurre il fenomeno fisico con elevata accuratezza. Quando i parametri hanno un significato fisico, risulta necessario controllare se il loro utilizzo, considerando le approssimazioni che il modello inevitabilmente comporta, permette di produrre risultati affidabili. A volte, tuttavia, i parametri che devono essere inseriti nel modello prescindono dalla natura fisica del caso in esame, ed hanno solamente un significato in termini matematici. Quando questo avviene, risulta ancor più importante calibrare il modello, cercando di cogliere l’intera complessità del fenomeno. Se la strategia di calibrazione non tiene conto dei vari aspetti che caratterizzano il caso di studio, infatti, i parametri ottenuti tramite back-analysis potrebbe non aver alcun senso. Questa tesi si pone l’obiettivo di sottolineare la complessità che può contraddistinguere il processo di calibrazione. Dopo aver deciso quale modello numerico utilizzare ed averne comprese possibilità e limitazioni, lo studio di casi di studio differenti permette di evidenziare le criticità e le problematiche che la back-analysis può presentare. A tale scopo, in questo lavoro vengono considerati principalmente tre casi di studio. Il primo riguarda il collasso di una colonna di materiale coesivo su di un piano orizzontale. Successivamente la procedura è applicata ad un gruppo di prove in canaletta condotte con diverse miscele di argilla e sabbia. Infine, viene analizzata la colata detritica avvenuta nel 2010 lungo il torrente Rotolon, situato in nella parte nord-occidentale del Veneto. È importante sottolineare che tutti i test di laboratorio sono stati eseguiti appositamente per la successiva applicazione della back-analysis, prestando quindi particolare attenzione alle modalità di acquisizione dei dati. Per tutti e tre i casi, è stata ricercata ed applicata una strategia di calibrazione per ridurre l’incertezza nell’identificazione dei parametri ottimali.
Wergin, Vivian Vanessa [Verfasser], Jürgen [Akademischer Betreuer] Beckmann, Günter [Gutachter] Amesberger, Jürgen [Gutachter] Beckmann, and Clifford J. [Gutachter] Mallett. "Collective sport team collapse - a process model / Vivian Vanessa Wergin ; Gutachter: Günter Amesberger, Jürgen Beckmann, Clifford J. Mallett ; Betreuer: Jürgen Beckmann." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1200547772/34.
Повний текст джерелаEby, Joshua. "Phenomenology and Astrophysics of Gravitationally-Bound Condensates of Axion-Like Particles." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1504868633515325.
Повний текст джерелаJesus, Thales Eduardo Silva de. "Imageamento digital de paleocavernas colapsadas com georadar." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/18821.
Повний текст джерелаIn this study, the methodological procedures involved in digital imaging of collapsed paleocaves in tufa using GPR are presented. These carbonate deposits occur in the Quixer? region, Cear? State (NE Brazil), on the western border of the Potiguar Basin. Collapsed paleocaves are exposed along a state road, which were selected to this study. We chose a portion of the called Quixer? outcrop for making a photomosaic and caring out a GPR test section to compare and parameterize the karst geometries on the geophysical line. The results were satisfactory and led to the adoption of criteria for the interpretation of others GPR sections acquired in the region of the Quixer? outcrop. Two grids of GPR lines were acquired; the first one was wider and more spaced and guided the location of the second grid, denser and located in the southern part of the outcrop. The radargrams of the second grid reveal satisfactorily the collapsed paleocaves geometries. For each grid has been developed a digital solid model of the Quixer? outcrop. The first model allows the recognition of the general distribution and location of collapsed paleocaves in tufa deposits, while the second more detailed digital model provides not only the 3D individualization of the major paleocaves, but also the estimation of their respective volumes. The digital solid models are presented here as a new frontier in the study of analog outcrops to reservoirs (for groundwater and hydrocarbon), in which the volumetric parameterization and characterization of geological bodies become essential for composing the databases, which together with petrophysical properties information, are used in more realistic computer simulations for sedimentary reservoirs.
Nesse trabalho s?o apresentados os procedimentos metodol?gicos envolvidos no imageamento digital de paleocavernas colapsadas em tufas carbon?ticas que ocorrem na borda oeste da Bacia Potiguar com GPR. Foi mapeada uma ?rea em Quixer? (CE) e selecionado um afloramento em um corte de estrada, denominado de Afloramento Quixer?. Foi escolhida uma por??o deste afloramento para confec??o de um fotomosaico e levantamento de uma se??o-teste com o GPR para a compara??o e parametriza??o das geometrias c?rsticas aflorantes e imageadas na linha geof?sica. Os resultados foram satisfat?rios e permitiram a ado??o de crit?rios para a interpreta??o das paleocavernas colapsadas em outras se??es GPR, levantadas na regi?o do afloramento. Foram adquiridas duas malhas de linhas GPR, a primeira mais ampla e espa?ada norteou a loca??o da segunda, mais adensada, na por??o sul do Afloramento Quixer?. Nos radargramas foram interpretadas e parametrizadas as geometrias das principais paleocavernas colapsadas. Para cada malha foi elaborado um modelo de s?lido digital do Afloramento Quixer?, sendo que o primeiro modelo permitiu o reconhecimento da distribui??o geral das tufas e a localiza??o das paleocavernas colapsadas, enquanto o segundo modelo digital, por ser mais detalhado, possibilitou n?o apenas a individualiza??o 3D das principais paleocavernas, mas tamb?m o c?lculo dos seus respectivos volumes. Os modelos de s?lidos digitais s?o aqui apresentados como uma nova fronteira no estudo de afloramentos an?logos a reservat?rios (h?dricos ou petrol?feros), na qual a parametriza??o e a caracteriza??o volum?trica dos corpos geol?gicos passam a ser fundamental para compor bancos de dados, que conjuntamente com informa??es de propriedades petrof?sicas s?o utilizados em simula??es computacionais mais real?sticas de reservat?rios.
Bezerril, Leonardo Mafra. "O Modelo de Ising inomog?neo: uma interrup??o cont?nua entre as redes quadrada e triangular." Universidade Federal do Rio Grande do Norte, 2007. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16536.
Повний текст джерелаConselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The ferromagnetic and antiferromagnetic Ising model on a two dimensional inhomogeneous lattice characterized by two exchange constants (J1 and J2) is investigated. The lattice allows, in a continuous manner, the interpolation between the uniforme square (J2 = 0) and triangular (J2 = J1) lattices. By performing Monte Carlo simulation using the sequential Metropolis algorithm, we calculate the magnetization and the magnetic susceptibility on lattices of differents sizes. Applying the finite size scaling method through a data colappse, we obtained the critical temperatures as well as the critical exponents of the model for several values of the parameter α = J2 J1 in the [0, 1] range. The ferromagnetic case shows a linear increasing behavior of the critical temperature Tc for increasing values of α. Inwhich concerns the antiferromagnetic system, we observe a linear (decreasing) behavior of Tc, only for small values of α; in the range [0.6, 1], where frustrations effects are more pronunciated, the critical temperature Tc decays more quickly, possibly in a non-linear way, to the limiting value Tc = 0, cor-responding to the homogeneous fully frustrated antiferromagnetic triangular case.
Investigamos o diagrama de fases do modelo de Ising, com intera??es feromagn?ticas e antiferromagn?ticas, emuma rede bidimensional inomog?nea caracterizada por duas constantes de troca (J1 e J2), a qual permite interpolar cont?nuamente as redes quadrada (J2 = 0) e triangular (J2 = J1) uniformes. Utilizando o m?todo de simula??o de Monte Carlo, atrav?s da din?mica deMetropolis aplicada de forma seq?encial, calculamos a magnetiza??o e a susceptibilidade para redes de diversos tamanhos e aplicando t?cnicas de escalonamento para tamanhos finitos obtemos, atrav?s de um colapso de dados, valores para a temperatura cr?tica e expoentes cr?ticos em fun??o do par?metro α = J2 J1, contido no intervalo [0, 1]. No caso ferromagn?tico observamos que a temperatura cr?tica Tc cresce linearmente com α em todo o intervalo de varia??o deste par?metro, enquanto no caso antiferromagn?tico, o comportamento linear (decrescente) de Tc ? observado somente para pequenos valores de α; no intervalo [0.6, 1], onde os efeitos de frustra??o s?o mais pronunciados, a temperatura cr?tica sofre uma redu??o mais significativa, possivelmente n?o linear, para seu valor limite Tc = 0, que corresponde ? rede triangular homog?nea, antiferromagn?tica, completamente frustrada.
Rezende, Bruna Luiza de Faria. "Modelos de colonização e colapso." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7779.
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In this work a basic immigration process was investigated which starts with a single colony with a single individual at the origin of a homogeneous tree with the other empty vertices. The process colonies are established at the vertices of the graph and each one grows during a random time, according to a process of general counting until a disaster that annihilates part of the population occurs. After the collapse a random amount of individuals survives and attempts to establish, in a independent manner, new colonies in a neighboring vertices. After a time these formed colonies also suffer catastrophes and the process is repeated. It is important to emphasize that the time until the disaster of each colony is independent of the others. Here this general process was studied under two methods, Poisson growth with geometric catastrophe and Yule growth with binomial catastrophe. That is, in each colony the population grows following a Poisson (or Yule), process during a random time, considered here exponential, and soon after that time its size is reduced according to the geometric (or binomial) law. Conditions were analyzed in the set of parameters so that these processes survived and limits were established that were relevant for the probability of survival, the number of colonies generated during the process and the range of the colonies in relation to the initial point.
Neste trabalho foi investigado um processo básico de imigração o qual é iniciado com uma única colônia com um único indivíduo na origem de uma árvore homogênea com os demais vértices vazios. As colônias do processo se estabelecem nos vértices do grafo e cada uma cresce durante um tempo aleatório, de acordo com um processo de contagem geral até ocorrer um desastre que aniquila parte da população. Após o colapso uma quantidade aleatória de indivíduos sobrevive e tenta estabelecer, de forma independente, novas colônias em vértices vizinhos. Depois de um tempo essas colônias formadas também sofrem catástrofes e o processo se repete. É importante enfatizar que o tempo até o desastre de cada colônia independe do das demais. Aqui esse processo geral foi estudado sujeito a dois métodos, crescimento de Poisson com catástrofe geométrica e crescimento de Yule com catástrofe binomial. Ou seja, em cada colônia a população cresce seguindo um processo de Poisson (ou Yule), durante um tempo aleatório, considerado aqui exponencial, e logo após esse tempo seu tamanho é reduzido de acordo com a lei geométrica (ou binomial). Foram analisadas condições no conjunto de parâmetros para que esses processos sobrevivam e foram estabelecidos limites relevantes para a probabilidade de sobrevivência, o número de colônias geradas durante o processo e o alcance das colônias em relação ao ponto inicial.