Angliavandenilių susidarymo modeliavimas buvo atliktas keliuose gręžiniuose siekiant nustatyti angliavandenilių generacijos amžių. Svarbiausi angliavandenilių ištekliai Baltijos sineklizėje yra susiję su kambro smiltainiais. Telkiniai taip pat surasti ir ordoviko bei silūro karbonatinėse uolienose. Pirmieji naftos modeliavimo darbai Lietuvoje pradėti XX a. paskutiniame dešimtmetyje. Pirmieji modeliai parodė, kad Vakarų Lietuvoje nafta pradėjo generuoti viduriniame devone ir apėmė kambro, ordoviko ir apatinio silūro motinines uolienas. 1D modeliavimas yra svarbus, jis suteikia pagrindinę informaciją apie vieno ar kito naftos ar dujų telkinio evoliucija Baltijos sineklizėje ir didėja susidomėjimas dujų skalūnų paieškose. Angliavandenilių generacijos modeliavimas Baltijos sineklizėje buvo atliktas su programa PetroMod. PetroMod naftos sistemos modeliavimo programa, sujungianti seisminius duomenis, gręžinių duomenis ir geologinę informaciją į vieningą 1D, 2D, 3D modelį. PetroMod programa turi galimybę nustatyti, kaip rezervuare susikaupė angliavandeniliai, įskaitant išteklių šaltinį ir laiką per kurį ištekliai susiformavo, migracijos kelius, kiekius ir angliavandenilio tipą gelmėse ir paviršiuje. Angliavandenilių sistemų modeliavimas yra svarbus komponentas angliavandenilių žvalgyboje – nuo idėjos iki baseino. Programa gali būti pritaikyta bet kurioje paieškų stadijoje, nuo pritaikymo neišžvalgytose teritorijose iki gerai išžvalgytų teritorijų ir apskaičiuoti angliavandenilių... [toliau žr. visą tekstą] / The main hydrocarbon sources of Baltic syneclise are related to Cambrian sandstones. There are also hydrocarbon fields in Ordovician and Silurian carbonate rocks. First hydrocarbon modeling in Lithuanian started in XX century last decade. The modeling showed what in western Lithuania oil started to generate in middle Devonian and took place in Cambrian, Ordovician and Silurian deposits. 1D modeling of hydrocarbon generation is vital and in present days, it’s giving basic information about one or another oil and gas fields evolution in Baltic syneclise and nowadays the importance is growing in shale’s gas evaluation. 1D modeling of hydrocarbon generation in Baltic syneclise was performed with software PetroMod. PetroMod petroleum systems modeling software combines seismic, well, and geological information to model the evolution of a sedimentary basin. The software predicts if, and how, a reservoir has been charged with hydrocarbons, including the source and timing of hydrocarbon generation, migration routes, quantities, and hydrocarbon type in the subsurface or at surface conditions. Petroleum systems modeling is a vital component of exploration risk assessment—from basin to prospect. It can be applied during all stages of exploration, from frontier basins with no well control, to well-explored areas and charge assessments of single prospects or fields. The hydrocarbon generation was estimated in 9 well’s: 4 well’s in western northern part of Lithuania, 2 well’s in middle... [to full text]

We explore the behavior of an integrodifferential equation used to model one-dimensional biological swarms. In this model, we assume the motion of the swarm is determined by pairwise interactions, which in a continuous setting corresponds to a convolution of the swarm density with a pairwise interaction kernel. For a large class of interaction kernels, we derive conditions that lead to solutions which spread, blow up, or reach a steady state. For a smaller class of interaction kernels, we are able to make more quantitative predictions. In the spreading case, we predict the approximate shape and scaling of a similarity profile, as well as the approximate behavior at the endpoints of the swarm (via solutions to a traveling wave problem). In the blow up case, we derive an upper bound for the time to blow up. In the steady state case, we use previous results to predict the equilibrium swarm density. We support our predictions with numerical simulations. We also consider an extension of the original model which incorporates external forces. By analyzing and simulating particular cases, we determine that the addition of an external force can qualitatively change the behavior of the system.

A transient, one-dimensional, model of the membrane of a proton exchange membrane fuel cell is presented. The role of the membrane is to transport protons from the anode to cathode of the fuel cell while preventing the transport of other reactants. The membrane is modeled assuming mono-phase, multi-species flow. For water transport, the principle driving forces modeled are a convective force, an osmotic force (i.e. diffusion), and an electric force. The first of these results from a pressure gradient, the second from a concentration gradient, and the third from the migration of protons from anode to cathode and their effect (drag) on the dipole water molecules. Equations are developed for the conservation of protons and water, the conservation of thermal energy, and the variation of proton potential within the membrane. The model is solved using a fully implicit finite difference approach. Results showing the effects of current density, pressure gradients, water and heat fluxes, and fuel cell start-up on water concentration, temperature, and proton potential across the membrane are presented. / Master of Science

This dissertation primarily documents the quantification of the interfacial behavior of carbon based nanomaterials, which includes two categories, one is the nanofriction properties evaluation of aligned carbon nanotube carpets, few-layer graphene as well as three types of functionalized graphene nanoribbons, the second is the mechanical characterization of individual functionalized carbon nanofibers and the interfacial fracture toughness quantification in carbon nanotube/polymer derived ceramics nanocomposite. The aligned carbon nanotube carpets have a highly anisotropic friction behavior, which means the friction force are lower for transversely aligned CNTs side than for vertically aligned CNTs surface. We can also tune the friction properties of graphene ribbons by grafting different functional groups. In addition, two narrow angular regions with high friction, separated by a wide angular interval with low friction, were identified between graphene and highly oriented pyrolytic graphite. The distance between the two friction peaks is 61◦, which corresponds well with the 60◦ symmetry of individual atomic layers in the graphite lattice. The technique that involves the usage of mcirodevices and nanoidenter was used to conduct tensile tests on pristine, fluorinated and amino-functionalized carbon nanofibers, which were found to exhibit varied load-bearing abilities and unique fracture modes. The technique was also used to perform single fiber pullout experiments to study carbon nanotube/polymer derived ceramic interface.

The enhancement of strength of nanoscale materials such as face-centered cubic metal nanowires is well known and arises largely from processes mediated by high energy surface atoms. This leads to strong size effects in nanoscale plasticity; ,smaller is stronger. Yet, other factors, such as crystalline defects also contribute greatly to the mechanical properties. In particular, twin boundaries, which are pervasive and energetically favorable defects in face-centered cubic metal nanowires, have been shown to greatly enhance the strength, furthermore this increase in strength has been shown to be directly influenced by the twin density. However, attempts to control the introduction of beneficial defects remains challenging. Additionally, even minor local variations in the crystalline structure or size of metal nanowires may have drastic effects on the yielding of metal nanowires, which are difficult to measure through tensile and bending tests. In this study, atomic force microscopy based nanoindentation techniques are used to measure the local plasticity of Ni-Au bimetallic as well as Cu and Ag metallic nanowires. In the first part of the thesis the hardness of bimetallic nanowires synthesized through template-assisted electrodeposition is measured and found to show significant size-effects. It was found that the nanoindentation hardness was governed by materials properties, the observed indentation size effects were dependent on geometrical factors. The second part of this thesis presents a methodology to control the crystal structure of Ag and Cu nanowires through direct electrodeposition techniques, which were tested directly as grown on the substrate to limit effects of pre-straining. Ag nanowires showed marked size-effects as well as two distinct modes of deformation which we attribute to the defects that arise during crystalline growth. We also show control of the surface microstructure in Cu nanowires which leads to strengths that are more than doubled compared to single crystalline Cu nanowires. Finally, we present support from classic crystal growth theory to justify that the observed plasticity in Ag and Cu nanowires is largely dependent on defects that are nucleated through changes in the growth environment.

The thesis is aimed at the characterization of carbon nanotubes and silver nanowires by Scanning Probe Microscopy, namely Scanning Tunneling Microscopy (STM), Atomic Force Microscopy (AFM), Conductive AFM (CAFM) and Scanning Near-Field Optical Microscopy (SNOM). Carbon nanotubes were analyzed by STM, AFM and CAFM microscopy. In a designed apparatus the silver nanowires were fabricated by template assisted deposition and were analyzed with respect to their geometry (AFM), local conductivity (CAFM) and optical properties (SNOM, microreflex spectroscopy). It was found that preferential type of carbon nanowires depends on the fabrication process. The measurements of local conductivity of the nanotubes revealed the similarity with the STM measurements. The AFM measurements of silver nanowires confirmed their growth inside the pores of polycarbonate template. Single nanowires exhibits the semiconducting behavior according to I--V measurement and localized plasmon resonances.

Les dispositifs magnéto-optiques (MO) sont les éléments de base des isolateurs optiques, éléments essentiels pour les lasers et LIDAR. Ils sont également utilisés pour l'imagerie, le stockage ou les capteurs. Une structuration périodique du matériau magnétique est un moyen pour en améliorer les performances, et ainsi réduire la taille des composants intégrés ou améliorés la sensibilité des capteurs associés. Cependant, la mise en œuvre des matériaux magnéto-optiques habituels au sein des platefo1mes d'optique intégrée est rendue difficile par la forte température de cristallisation (- 7000C) qu'ils requièrent. En utilisant un processus sol-gel basse température, une matrice de silice peut être dopée par des nanoparticules magnétiques (C0Fe204) pour produire un matériau qui présente une excellente compatibilité avec les substrats photoniques. Dans ce travail, ce matériau composite a été utilisé pour imprégner un réseau grâce à un dépôt en une seule étape à une température inférieure à 100 °C. Il s'agit d'un réseau lD ShN4 sur verre. Des simulations numériques, basées sur les méthodes RCW A, et réalisées à 1,55 µm ont permis de déterminer les paramètres adéquats pour obtenir un réseau résonnant, simultanément pour les polarisations TE et TM, à incidence normale. Les simulations MO ont démontré que ce type de structure permet d'obtenir l'exaltation de tous les effets magnéto-optiques classiques (Kerr et Faraday). Le facteur de mérite théorique obtenu est comparable voir supérieur à ceux rapportés dans la littérature qui utilisent des matériaux MO classiques. Ces améliorations ont été confirmées par des réalisations et caractérisations expérimentales. Par exemple, une augmentation de la rotation de Faraday d'un facteur 3,5 a été obtenue par rapport à un film mince de référence. Le facteur de mérite correspondant était comparable voir supérieur à ceux présentés dans la littérature prouvant la grande efficacité de notre structure. Les résultats de ce travail sont la première démonstration d'une augmentation de tous les effets MO avec un seul dispositif / Magneto-optical (MO) devices are the basic elements of optical isolators essential for lasers an1 LIDAR, and are also employed for aircraft imaging, data storage or sensing. A periodic structuration of the core magnetic material is a way to enhance its MO behavior, and is thus useful to reduce the footprint of integrated devices or to improve the sensitivity of related sensors. However, the processing of efficient magnetic materials on photonic platforms is still challenging, because classical MO materials require an annealing temperature as high as 700°C. Using a sol-gel process, a silica matrix can be doped by magnetic nanoparticles (C0Fe204) to produce a MO material which possess a full compatibility with photonic substrates. In this work, this composite material was incorporated into an already structured template through a single step deposition at low temperature. The template was a 1-D SiJN4 grating on glass. Numerical simulations, based on RCW A methods, have been carried out to identify the suitable values of the grating period and the line-space ratio which produce a guided-mode resonance at 1.55 µm simultaneously for TE and TM polarizations, at normal incidence. MO simulations demonstrated that an enhancement of magneto-optical effects is obtained in transmission or reflection for every orientation of the applied magnetic field (Kerr or Faraday effects). The theoretical figure of merit for these structures were comparable or higher than those reported in literature which use classical MO materials. These enhancements were confirmed by experimental realizations and measurements. For instance, a Faraday rotation enhancement of 3.5 times was demonstrated compared to the reference thin-film. The c01Tesponding figure of merit was comparable or higher than those reported in literature proving the high efficiency of our structure. The results of this work are the 1st demonstration of an enhancement of every MO effect with a single device

Le domaine des problèmes inverses est une discipline qui se trouve à la frontière des mathématiques appliquées et de la physique et qui réunit les différentes solutions pour résoudre les problèmes d'optimisation mathématique. Dans le cas de la déconvolution 1D, ce domaine apporte un formalisme pour proposer des solutions avec deux grands types d'approche: les problèmes inverses avec régularisation et les problèmes inverses bayésiens. Sous l'effet du déluge de données, les géosciences et la planétologie nécessitent des algorithmes de plus en plus plus complexe pour obtenir des informations pertinentes. Dans le cadre de cette thèse, nous proposons d'apporter des connaissances dans trois problèmes de déconvolution 1D sous contrainte avec régularisation dans le domaine de l'hydrologie, la sismologie et de la spectroscopie. Pour chaque problème nous posons le modèle direct, le modèle inverse, et nous proposons un algorithme spécifique pour atteindre la solution. Les algorithmes sont définis ainsi que les différentes stratégies pour déterminer les hyper-paramètres. Aussi, des tests sur des données synthétiques et sur des données réelles sont exposés et discuté du point de vue de l'optimisation mathématique et du point de vue du domaine de l'application choisi. Finalement, les algorithmes proposés ont l'objectif de mettre à portée de main l'utilisation des méthodes des problèmes inverses pour la communauté des Géosciences. / The inverse problem field is a domain at the border between applied mathematics and physics that encompasses the solutions for solving mathematical optimization problems. In the case of 1D deconvolution, the discipline provides a formalism to designing solutions in the frames of its two main approaches: regularization based inverse problems and bayesian based inverse problems. Under the data deluge, geosciences and planetary sciences require more and more complex algorithms for obtaining pertinent information. In this thesis, we solve three 1D deconvolution problems under constraints with regularization based inverse problem methodology: in hydrology, in seismology and in spectroscopy. For every of the three problems, we pose the direct problem, the inverse problem, and we propose a specific algorithm to reach the solution. Algorithms are defined but also the different strategies to determine the hyper-parameters. Furthermore, tests on synthetic data and on real data are presented and commented from the point of view of the inverse problem formulation and that of the application field. Finally, the proposed algorithms aim at making approachable the use of inverse problem methodology for the Geoscience community.

En Power Transfer Unit (PTU) eller vinkelväxel i ett drivsystem för allhjulsdrift är enväxellåda med en hypoid-växel som drevsats. PTUn ar placerad mellan fordonets transmissionoch kardanaxel och används för att fördela momentet från drivsystemet mellanalla hjulen. De dynamiska egenskaperna hos vinkelväxeln är kopplade till de ljud ochvibrationer som uppfattas i bilen, speciellt tonalt ljud som växelvin. Källan till dennavibration kan relateras till transmissionsfelet i växeln. Transmissionsfelet beror pa faktorersom geometri, rotationshastighet och statiskt moment. Om faktorernas inverkankan identieras skapar det möjligheter att reducera felet genom designförändringar. 1D ellersystem-simulering ar en förenklad beskrivning av det dynamiska beteendet av systemet.Det är en flexibel metod som kan ge en uppskattning av systemets egenskaper iett tidigt skede och kan användas i såväl tids- som frekvensdomönen.Denna studie syftar till att bygga en 1-D system-modell av en PTU och studera dessdynamiska beteende. De typer av analyser och resultat som ar möjliga att få från en dynamisk1-D modell av en specic produkt har utvärderats. Befintliga komponenter frånmjukvarans bibliotek har används for att bygga en förenklad modell med lumpade massorav den fysiska systemet. Simuleringar har utförts både i tidsdomänen och frekvensdomänen.System-modellen är mycket användbar för modelling av hela system och av hur delarnaväxelverkar i ett tidigt skede av produktutvecklingen. Beräkningen av nivån på transmissionsfeletsgrundtonen stämmer väl med tillgängliga mätresultat. Rotationshastigheternasvariation då kopplingen kopplar i och ur vinkelväxeln illustrerar tydligt kopplingensinverkan på dynamiken i systemet. Det var dessutom möjligt att erhålla systemets torsionsegenfrekvenseroch modformer från den linjära frekvensanalysen. / A Power Transfer Unit (PTU) of an All-Wheel Drive system is a hypoid gearbox whichis a driveline component, used to distribute power from the powertrain to all the wheelsof a vehicle. The gearbox dynamics is closely related to the gearbox noise and vibration,especially tonal noise like gear whine. The source of this vibration is referred to as thetransmission error in the unit. Transmission error is attributed to various geometricaland operating conditions, which if mapped mathematically, allows the designer to reducethe error by varying the design parameters. The demand in the automotive industry toreduce time to market is high. A lot of time can be saved if system performance can beassessed at the concept stage, even before the detailed design. This is where system-levelsimulation plays a key role. 1-D or system simulation technique studies the dynamicbehaviour of the system in one dimension. This greatly simplies the model and allowsfor the exibility to get early estimates of the system behaviour with respect to time andfrequency. Here, such a system model is built for a hypoid gear based driveline system.This work aims to build a 1-D system model of the PTU and study the dynamic behaviourof the response. The evaluation helps in understanding the capabilities on 1-D systemmodel in simulating a specialised product dynamic characteristics. LMS AMESim wasthe commercial tool used in building the system model. Existing components from thesoftware library were used to build a sketch of a simplied, lumped mass model of thephysical system. The model was then simulated in both the time domain and frequencydomain through a temporal and linear analysis respectively.It is observed that the system model is very useful in early modelling of a system and itsinteractive eects. The fundamental harmonic of the transmission error is predicted wellin the system model. The clutch connect/disconnect behaviour can also be seen in therotary velocity response of the gear. The system eigenfrequencies and mode shapes wereobtained from the linear analysis.

"In the past decade nanomaterials have attracted the interest of scientists and engineers all over the world due to their unique properties. Through their devoted experimental efforts, limited advances have been made on the synthesis of nanomaterials, the integration of nanomaterials into the structures of larger scales, and the property study of nanomaterials to explore possible applications. Despite the huge amount of money, resources, and effort invested in nanomaterials, several challenges still remain as obstacles on the way towards the successful large scale use of nanomaterials to benefit human life and society. For example, the need for low-cost, robust, and highly productive manufacturing methods and the demand for efficient integration of nanomaterials with materials and devices of larger length scales are still left unmet. The objective of this work was to utilize cost-efficient nanofabrication methods such as template-assisted fabrication, electrodeposition, and chemical vapor deposition to fabricate nanomaterials, integrate nanomaterials with larger structures to form a hierarchical composite, and explore the application of unique nanostructured electrode in lithium-ion batteries. Thus the thesis consists of three main parts: (1) fabrication of one-dimensional inorganic nanomaterials such as metal nanowires, metal nanorods, and carbon nanotubes with good control over shape and dimension; (2) synthesis of hierarchical carbon nanofibers on carbon microfibers and/or glass microfibers; and (3) development of nanostructured anodes to improve high-rate capability of lithium-ion batteries by adapting nanorod arrays as miniature current collectors. "