Dans ce travail, nous étudions le raffinement de maillage pour des méthodes d'éléments finis mixtes duales pour deux types de problèmes : le premier concerne le problème de l'élasticité linéaire et le second problème celui de l'élastodynamique.<br /> <br /> Pour ces deux types de problèmes et dans des domaines non réguliers, les méthodes d'éléments finis mixtes analysées jusqu'à présent, sont celles qui concernent des méthodes mixtes "classiques". Ici, nous analysons la formulation mixte duale pour les deux problèmes de l'élasticité linéaire et de l'élastodynamique. <br /> Pour le problème d'élasticité, nous sommes concernés premièrement par une analyse a priori d'erreur en utilisant l'approximation par l'élément fini $BDM_1$ stabilisé. Afin de dériver une estimation a priori optimales d'erreur, nous établissons des règles de raffinement de maillage. <br /> Ensuite, nous faisons une analyse d'erreur à posteriori sur un domaine simplement ou multiplement connexe. En fait nous établissons un estimateur résiduel fiable et efficace. Cet estimateur est alors utilisé dans un algorithme adaptatif pour le raffinement automatique de maillage. Pour le problème de l'élastodynamique, nous faisons une analyse a priori d'erreur en utilisant le même élément fini que pour le problème d'élasticité, en utilisant une formulation mixte duale pour la discrétisation des variables spatiales. <br /> Pour la discrétisation en temps nous étudions les deux schémas de Newmark explicite et implicite. Par des règles de raffinement de maillage appropriées, nous dérivons des estimées d'erreur optimales pour les deux schémas numérique.

Cette thèse est un recueil de trois essais, chacun correspondant à un chapitre. Le premier chapitre procède à l'analyse des<br />causes de la faible croissance de l'Afrique en s'appuyant sur l'argument dit « des politiques ». C'est ainsi qu'il convoque la littérature<br />mettant l'accent sur le rôle de l'instabilité des politiques et utilise le modèle de l'économie dépendante comme fondement théorique.<br />Le chapitre explore les effets potentiels de l'instabilité des dépenses publiques et du taux de change réel sur la dynamique de<br />croissance ainsi que les canaux de transmission à travers lesquels ces effets prennent corps. Les résultats de l'analyse empirique<br />révèlent que l'instabilité des dépenses publiques exacerbe l'instabilité du taux de change réel, qui, en retour, exerce un effet négatif<br />tant sur l'investissement que sur la productivité globale des facteurs. Par ailleurs, l'analyse empirique indique, en partie, que<br />l'appréciation du taux de change réel contribue au déclin des secteurs à forte externalités positives, contribuant ainsi à des pertes<br />continues de productivité et à une croissance économique atone. Ces résultats impliquent que la stabilité des dépenses publiques et du<br />taux de change réel est cruciale pour la croissance économique à long-terme du continent.<br />Le second chapitre s'intéresse à la problématique politiques économiques et pauvreté et s'appuie, également, sur le modèle<br />de l'économie dépendante. Le chapitre part des dépenses publiques et, dans une large mesure, du taux de change réel et explore les<br />liens entre ces deux variables et la pauvreté. L'analyse empirique, reposant sur un échantillon de pays africains et non-africains,<br />montre que la dépréciation du taux de change réel favorise les pauvres, à condition que les inégalités de revenus ne soient pas criardes<br />et que les institutions fonctionnent adéquatement. Il découle de ces résultats empiriques que la dépréciation du taux de change réel<br />peut être un puissant outil au service de la réduction de la pauvreté si elle est complémentée par d'autres politiques. Ces politiques<br />comprennent entre autres : faciliter l'accès des pauvres aux facteurs de production et améliorer la qualité des institutions.<br />S'inscrivant dans la droite ligne de la littérature liant les choix de politiques aux régimes politiques, le troisième et dernier<br />chapitre porte un regard sur les implications du processus de démocratisation enclenché en Afrique sur les propriétés cycliques de la<br />politique budgétaire. La principale question à laquelle essaie de répondre ce chapitre est de savoir si les institutions démocratiques ont<br />facilité l'adoption de politiques budgétaires contra-cycliques sur le continent. L'analyse empirique y répond en montrant une<br />corrélation positive entre institutions démocratiques et politiques budgétaires contra-cycliques. De plus, et ce point est sans doute le<br />plus important, les institutions formelles ayant pour vocation de contrebalancer le poids de l'exécutif s'avèrent être le principal facteur<br />qui explique pourquoi les démocraties lissent mieux les cycles économiques que les autocraties.

Modeling at the structural scale most often requires the use of beam and shell elements. This simplification reduces modeling complexity and computation requirements but sacrifices the accuracy of through-the-thickness information. Several studies have reported various design approaches for analyzing functionally graded material structures. One of these studies proposed a two-node beam element for functionally graded materials (FGMs) based on first order shear deformable (FOSD) theory. The derivation of governing equations included spatial temperature variation. However, only the constant temperature case was carried through in the element formulation. This investigation explore the effects of spatial temperature variation in the axial and through-the-thickness direction of this proposed element and present a new standard three-node beam finite element modified for structure constructed of FGMs. Also, the influence of the temperature dependency of the thermo-elastic material properties on the thermal stresses distribution was studied. In addition, variations in the layer thicknesses within multilayer beam models were studied to determine the effect on stresses and factor of safety. Finally, based on the specific factor of safety, which combines together the strength and mass of the beam, the best layer thicknesses for the beam models were established. The key contributions expected from this research are: 1. development and implementation of a three-node beam element as a finite element code into the commercial computational tool MATLAB® to analyze thermo-mechanical stresses in structures constructed of functionally graded materials; 2. a strategy to simulate different load cases in structures constructed of functionally graded materials; 3. an analysis of the influence of the FGM interlayer thickness on the factor of safety/specific gravity ratio in structures constructed of functionally graded materials under thermo-mechanical loads; 4. and an analysis/comparison of the advantages/benefits of using structures constructed of functionally graded materials with respect to those constructed with homogenous materials.

Multiphase flow is a familiar phenomenon from daily life and occupies an important role in physics, engineering, and medicine. The understanding of multiphase flows relies largely on the theory of interfaces, which is not well understood in many cases. To date, the Navier-Stokes-Korteweg equations and the Cahn-Hilliard equation have represented two major branches of phase-field modeling. The Navier-Stokes-Korteweg equations describe a single component fluid material with multiple states of matter, e.g., water and water vapor; the Cahn-Hilliard type models describe multi-component materials with immiscible interfaces, e.g., air and water. In this dissertation, a unified multiphase fluid modeling framework is developed based on rigorous mathematical and thermodynamic principles. This framework does not assume any ad hoc modeling procedures and is capable of formulating meaningful new models with an arbitrary number of different types of interfaces. In addition to the modeling, novel numerical technologies are developed in this dissertation focusing on the Navier-Stokes-Korteweg equations. First, the notion of entropy variables is properly generalized to the functional setting, which results in an entropy-dissipative semi-discrete formulation. Second, a family of quadrature rules is developed and applied to generate fully discrete schemes. The resulting schemes are featured with two main properties: they are provably dissipative in entropy and second-order accurate in time. In the presence of complex geometries and high-order differential terms, isogeometric analysis is invoked to provide accurate representations of computational geometries and robust numerical tools. A novel periodic transformation operator technology is also developed within the isogeometric context. It significantly simplifies the procedure of the strong imposition of periodic boundary conditions. These attributes make the proposed technologies an ideal candidate for credible numerical simulation of multiphase flows. A general-purpose parallel computing software, named PERIGEE, is developed in this work to provide an implementation framework for the above numerical methods. A comprehensive set of numerical examples has been studied to corroborate the aforementioned theories. Additionally, a variety of application examples have been investigated, culminating with the boiling simulation. Importantly, the boiling model overcomes several challenges for traditional boiling models, owing to its thermodynamically consistent nature. The numerical results indicate the promising potential of the proposed methodology for a wide range of multiphase flow problems. / text

The success of regenerative cardiac therapy requires reestablishing a capable blood supply via vasculature. The objective of this study was to develop an optimal scaffold formulation for de novo collateral vessel growth of aortic grafts using modified fibrin clots. This ex vivo vascular outgrowth model can be used to interrogate the complex cell or tissue interactions on the angiogenic front as vessels are formed. Based on formulation constraints, the methods used here may provide a clinically applicable option for guided collateral formation. Once understood, the methods and procedures can be tested and modified as necessary for in vivo, in situ regenerative therapy. Aortic segments from wild-type (C57BL/6J) and apolipoprotein-E deficient (ApoE) atherosclerosis-prone mice were cultured in a 3D environment created by various formulations of PEGylated fibrin. Aortic outgrowth was assessed and the optimal formulation was chosen to test the formation of de novo vascular circuits -- the first step necessary for collateral artery formation. The cultures were examined by conventional and confocal microscopy as well as by optical coherence tomography. Experiments testing the relationship between fibrin PEGylation and aortic vascular outgrowth showed that PEGylating fibrinogen prior to clot formation increased outgrowth over non-PEG control (n=6, p<.05) at lower fibrin concentrations. Lowering fibrin concentration to 10, 5, or 2.5mg/ml resulted in significantly higher outgrowth that was 1.92, 2.04, or 2.20 times that of 20mg/ml PEGylated fibrin gels. When multiple aortic segments are cultured in proximity, microvascular outgrowths visually anastamose suggesting that aorta-aorta conduits can be formed in fibrin based hydrogels. Anastomosing circuits appeared between wild-type aortic segments as well as between wild-type and atherosclerotic prone ApoE knockout segments. Fibrin gels, with or without PEGylation, form scaffolds suitable for regenerative vascular outgrowth ex vivo in normal and atherogenic environments. PEGylating fibrin prior to thrombin-initiated polymerization will allow the incorporation of growth factors or other bioactive components, making this a customizable therapy for guided collateral formation. Additionally, the incorporation of PEG itself does not limit and may actually increase the outgrowth from aortic segments in lower density gels. Finally, PEGylated fibrin gels offer an environment that will promote vascular extensions that visually anastamose, making this a viable model for ex vivo collateral formation. / text

This thesis describes the application of multivariate methods in a novel approach to the formulation of tablets for direct compression. It begins with a brief historical review, followed by a basic introduction to key aspects of tablet formulation and multivariate data analysis. The bulk of the thesis is concerned with the novel approach, in which excipients were characterised in terms of multiple physical or (in most cases) spectral variables. By applying Principal Component Analysis (PCA) the descriptive variables are summarized into a few latent variables, usually termed scores or principal properties (PP’s). In this way the number of descriptive variables is dramatically reduced and the excipients are described by orthogonal continuous variables. This means that the PP’s can be used as ordinary variables in a statistical experimental design. The combination of latent variables and experimental design is termed multivariate design or experimental design in PP’s. Using multivariate design many excipients can be included in screening experiments with relatively few experiments. The outcome of experiments designed to evaluate the effects of differences in excipient composition of formulations for direct compression is, of course, tablets with various properties. Once these properties, e.g. disintegration time and tensile strength, have been determined with standardised tests, quantitative relationships between descriptive variables and tablet properties can be established using Partial Least Squares Projections to Latent Structures (PLS) analysis. The obtained models can then be used for different purposes, depending on the objective of the research, such as evaluating the influence of the constituents of the formulation or optimisation of a certain tablet property. Several examples of applications of the described methods are presented. Except in the first study, in which the feasibility of this approach was first tested, the disintegration time of the tablets has been studied more carefully than other responses. Additional experiments have been performed in order to obtain a specific disintegration time. Studies of mixtures of excipients with the same primary function have also been performed to obtain certain PP’s. Such mixture experiments also provide a straightforward approach to additional experiments where an interesting area of the PP space can be studied in more detail. The robustness of a formulation with respect to normal batch-to-batch variability has also been studied. The presented approach to tablet formulation offers several interesting alternatives, for both planning and evaluating experiments.

Strateginis valdymas yra pagrindinė magistrinio darbo „Bioetanolio gamybos verslo įmonės valdymo strategijos modeliavimas“ tema. Strateginis valdymas yra pateikiamas ne tik kaip teorinis procesas, susidedantis iš strateginės analizės, strategijos formavimo ir strategijos ��gyvendinimo etapų, bet ir praktinis modelis, taikytinas bioetanolio gamybos verslo atveju. Bioetanolio verslas Lietuvos rinkoje yra pakankamai nauja veiklos sritis, pasižyminti nedideliu konkurentų skaičiumi ir nesuformuotais produkcijos realizavimo kanalais. Dėl šios priežasties didžioji dalis bioetanolio produkcijos yra eksportuojama. Tačiau palanki teisinė aplinka, sąlygoja geras vystymosi ir plėtros tendencijas ir vietinėje rinkoje. Siekiant suformuoti tikslingą bioetanolio gamybos verslo strateginio valdymo modelį, yra atlikti tiek teoriniai, tiek empiriniai tyrimai. Jų rezultatai sudarė sąlygas ne tik pasirinkti greito įsiskverbimo į vietinę rinką ir eksporto per prekybos tarpininkus strategijas, bet ir parengti veiksmų (finansų, marketingo, gamybos, organizacinių) programas bei įvertinti finansines-investicines strateginio valdymo įgyvendinimo proceso galimybes ir identifikuoti įgijamus konkurencinius pranašumus rinkoje. / Strategic management is the main Master‘s “Modelling of management strategy in business of bioethanol industry” thesis. Strategic management is considered not only as theoretical process, including strategic analysis, strategy formulation and strategy implementation stages, but also as practical model, applicable in bioethanol industry. Bioethanol industry is quite new activity field in Lithuanian market, characterized by a little number of competitors and unformed distribution channels of production. For that reason the vast majority of bioethanol production is being exported. But favourable legal enviroment causes good development and expansion tendencies in local market as well. To form a model of strategic management of bioethanol industry, it have been made and defined theoretical and empirical researches. The results caused both an opportunity to select a fast infiltration to local market and export by sales agents strategies and to formulate such operational programmes as finance, marketing, organizational and production. There is also a possibility to evaluate financial opportunities of implementation of strategic management process and to indicate the main competitive advantages in the market.

Modélisation des équations électromagnétiques 3D couplées avec les circuits d'alimentation électrique et le déplacement de parties mobiles, dans le cas de machines électriques tournantes. La formulation choisie utilise, comme inconnue principale, le potentiel vecteur magnétique nonjaugé, int~rpolé sur des éléments finis d'arête. Le caractère compatible de la formulation est assuré par l'introduction d'un potentiel vecteur électrique pour représenter le courant source, tant pour les inducteurs filaires maillés que pour les inducteurs filaires non-maillés. Le circuit électrique d'alimentation est analysé par la méthode des potentiels électriques intégrés dans le temps et les systèmes électrique et magnétique sont résolus simultanément. La connexion entre les parties mobiles est les parties fixes se fait par une technique d'interpolation des maillages, adaptée aux éléments d'arête. Des méthodes numériques spécifiques ont été développées et implantées, notamment pour l'intégration en pas-à-pas dans le temps du système temporel du premier ordre et pour la résolution du système matriciel résultant. L'ensemble des développements effectués a été validé sur un moteur à réluctance variable.

Meloksikamas, (4-hidroksi-2-metil-N-(5-metil-2-tiazolil)-2H-1,2-benzotiazin-3-karboksamid-1,1-dioksidas), yra nesteroidinis vaistas nuo uždegimo (NVNU), selektyvus ciklooksigenazės-II (COX-II) inhibitorius ir naudojamas reumatoidiniam artritui, osteoartritui ir kitoms sąnarių ligoms gydyti. Jis yra žymiai efektyvesnis ir sukelia mažiau šalutinių poveikių virškinamąjam traktui lyginant su kitais tradiciniais nesteroidiniais vaistais nuo uždegimo (NVNU). Gydomoji meloksikamo paros dozė (15 mg) yra viena mažiausių lyginant su kitais tradiciniais nesteroidiniais vaistais nuo uždegimo (NVNU). Europoje ir Lietuvoje yra registruotos tik peroralinės ir parenteralinės meloksikamo vaistų formos. Todėl siekiama sukurti transdermalines meloksikamo vaistų formas. Šio darbo tikslas – sukurti meloksikamo išsiskyrimo iš tirpalų pro dializės membraną in vitro metodą ir įvertinti išsiskyrusio meloksikamo kiekį. Tyrimo metu buvo naudojamas 1 proc. meloksikamo propileno glikolio tirpalas. Dializės membrana - regeneruotos celiuliozės. Akceptorinis tirpalas – buferinis tirpalas, kurio pH reikšmė 8,5. Palaikoma temperatūra - 37°C. Bandiniai buvo imami po 15, 30, 60, 120, 180 ir 300 minučių. Išsiskyręs meloksikamo kiekis iš bandinių kiekybiškai buvo vertinamas efektyviosios skysčių chromatografijos (HPLC) metodu. Didžiausias meloksikamo srautas (346, 963 µg/cm²/h) buvo po 15 minučių nuo eksperimento pradžios. Vėliau meloksikamo srautas mažėjo. Mažiausias meloksikamo srautas (67,401 µg/cm²/h)... [toliau žr. visą tekstą] / Meloxicam, (4-hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1, 2-benzothiazine-3-carbox-amide-1, 1-dioxide), a non-steroidal anti-inflammatory drug (NSAID) and selective cyclooxygenase-II (COX-II) inhibitor, is used in the treatment of rheumatoid arthritis, osteoartritis and other joint diseases. It has comparable efficiency and greater gastric tolerability in comparison to conventional non-steroidal anti-inflammatory drugs (NSAIDs). The efficiency dose of meloxicam (15 mg/day) is one of the lowest in the non-steroidal anti-inflammatory drugs (NSAIDs). There are registered only oral and parenteral formulations of meloxicam in Europe and Lithuania. So it is strive to create transdermal formulations of meloxicam. The aim of the present work was to develop in vitro meloxicam release through dialysis membrane method and measure the amount of released meloxicam. On release of meloxicam from 1 % meloxicam propylene glycol solution was used regenerated cellulose dialysis membrane. As acceptor fluid was used buffer pH 8,5. Temperature was controlled at 37°C. Samples 1 ml were withdrawn at intervals of 15, 30, 60, 120, 180 and 300 min. The quantitative determination of meloxicam in samples was performed by high performance liquid chromatography (HPLC). The maximum flux of meloxicam (346,963 µg/cm²/h) was after 15 min from the beginning of the experiment. Later on meloxicam flux was on the decrease. The minimum flux of meloxicam (67,401 µg/cm²/h) was after 300 min from the beginning of... [to full text]

Baigiamajame magistro darbe „Marketingo strategija plėtojant lauko vaizdo reklamos verslą“ išskiriama lauko vaizdo reklamos verslo problema, jos plėtojimo aktualijos. Nagrinėjama marketingo strategijos sąvoka. Išanalizavus ir susiteminus literatūrą marketingo strategijos planavimo, formulavimo ir įgyvendinimo klausimu, pateiktas teorinis marketingo strategijos modelis, tinkantis lauko vaizdo reklamos verslui. Išorinės reklamos rinkoje aplinka nuolat kinta, aštrėja įmonių konkurencinė kova, todėl darbe siekiama išanalizuoti lauko vaizdo reklamos verslo ypatumus, marketingo aplinką ir nustatyti palankias ir negatyvias rinkos tendencijas. Taip pat atliekama tipinės lauko vaizdo reklamos �����monės vidinės aplinkos analizė, įvertinamas marketingo komplekso efektyvumas ir nustatomos įmonės stipriosios ir silpnosios veiklos pusės. Remiantis išorine, įmonės aplinkos analizėmis ir atliktų tyrimų duomenimis, suformuluojama marketingo strategija, skirta lauko vaizdo reklamos verslui, kuri suteiktų pranašumų rinkoje. Darbo pabaigoje pateikiamos baigiamojo magistro darbo išvados. Darbo apimtis – 101 p. teksto be priedų, 33 iliustr., 15 lent., 86 bibliografiniai šaltiniai. Atskirai pridedami darbo priedai. / Master thesis “Marketing Strategy Developing Business of Outdoor Video Screens Advertisement” sets out to examine the specifics of market strategy planning, formulation ant implementation, to display opportunities of publicity. The author of thesis, according to analysis of theory, suggests the theoretical model of marketing strategy suitable for outdoor video advertisement. The rapidly changing environment in advertising business and growth of competition between enterprises in the outdoor advertisement sector is creating new requirements for companies. Therefore, the thesis seeks to assess outdoor video advertisement business market environment and determine its opportunities and threats. Also thesis examines business internal capabilities, assesses marketing mix and determines strengths and weaknesses. Then, using situation analysis results, a marketing strategy is being developed, which would improve the outdoor video advertisement business marketing performance. Marketing strategy is being presented by implementation model. Finally the conclusions are proposed. It is proposed marketing competitive strategy model for an outdoor video advertisement servise development. The volume of thesis is 101 p. of text without appendixes, 33 figures, 15 tables, 86 sources of literature. Appendixes are included separately.