Aujourd'hui, la durabilité des structures en matériau cimentaire est un des facteurs importants dans les domaines du génie civil et du génie industriel. Elle est influencée non seulement par les chargements mécaniques mais aussi par l'environnement (pollution, pluie...). Ces influences deviennent plus importantes quand on doit garantir une durée de service du matériau pendant une grande période. Le mécanisme de dégradation chimique du matériau cimentaire consiste à une décalcification progressive au cours du temps en contact avec un environnement agressif (par exemple l’attaque par les chlorures, par les sulfates, les cycles gel-dégel, l’alcali-réaction). Cette dégradation provoque la variation de la porosité du béton qui modifie les propriétés physico-chimiques et mécaniques. D'une part cette variation de porosité accélère le processus de transport de matières et entraîne une accélération de la dissolution des hydrates (notamment la portlandite). D'autre part, ceci induit une modification des propriétés mécaniques, notamment le retrait. En plus, les sollicitations mécaniques créent des microfissures qui peuvent être des facteurs accélérant le processus de dégradation chimique. Ce travail de thèse est réalisé pour étudier le phénomène physico-chimique de la carbonatation sur les matériaux cimentaires comme les mortiers et les pâtes de ciment à la base CEM I et CEM III. Le but principal de cette étude est de caractériser expérimentalement et numériquement les effets du dioxyde de carbone (CO2) sur la durabilité et les propriétés mécaniques d’un matériau cimentaire. Dans la partie expérimentale, nous prenons en compte quelques paramètres importants tels que : le retrait, la variation de la porosité et de la masse en fonction de différentes teneurs en dioxyde de carbone (CO2) : 5%, 10%, 13%, 15%, 17%, 20%. Le modèle numérique basé sur l’approche physico-chimique de Bary et Sellier (2004) nous permet de valider les paramètres qui influencent le phénomène de carbonatation en matériau cimentaire comme le taux de saturation en eau, la pression partielle de dioxyde de carbone (CO2), la concentration en ions calcium et la porosité. Ceci confirme que les transferts de dioxyde de carbone (CO2) en phase gazeuse couplent avec les transferts de l’eau liquide et des ions du calcium Ca2+ en solution aqueuse au cours de la carbonatation. / Today, the durability of structures in cementitious materials is an important factor in the areas of civil engineering and industrial engineering. It is influenced not only by mechanical loads but also by the environment (pollution, rain ...). These influences become more important when one has to guarantee a service life of materials for a great period. The mechanism of chemical degradation of the cementitious material is a progressive decalcification over time in contact with aggressive environments (e.g. attack by chlorides, by sulfates, freeze-thaw cycles, alkali reaction). This degradation causes the variation in the porosity of the concrete that modifies the physico-chemical and mechanical properties. On the one hand, the change in porosity accelerates the transport of substances and causes an acceleration of the dissolution of hydrates (notably portlandite). Moreover, this induces a change in mechanical properties, especially shrinkage of carbonation. In addition, the mechanical stress creating microcracks that may be factors accelerating the process of chemical degradation. This work is carried out to study the physicochemical phenomenon of carbonation on cement-based materials such as mortars and cement pastes based on CEM I and CEM III. The main purpose of this study is to characterize experimentally and numerically the effects of carbon dioxide (CO2) on the mechanical properties and durability of cementitious material. In the experimental part, we take into account some important parameters such as shrinkage, variation of porosity and variation of mass in terms of different concentrations of carbon dioxide (CO2): 5%, 10%, 13%, 15%, 17%, 20%. The numerical model based on the physico-chemical approach by Bary and Sellier (2004) allows us to validate the parameters that influence the carbonation in cementitious material as rate of water saturation, partial pressure of carbon dioxide (CO2), calcium ion concentration and porosity. This confirms that the transfer of carbon dioxide (CO2) in gas phase couple with transfers of liquid water and calcium ions Ca2 + in aqueous solution during carbonation.

A dynamic model in which multiple consumers of a single nutrient may coexist in a fluctuating environment is given. Only one consumer can persist in a fixed environment, but coexistence may be produced by effects of a fluctuating environmental variable on nutrient utilization differing between consumers. An approximate solution is given for the non-autonomous Lotka-Volterra-Verhulst ordinary differential equations of the model together with heuristic sufficient conditions for construction of a persistent multispecies consumer community. Computational examples demonstrate persistence of an idealized example community for periodic and random environmental fluctuation. Two further examples demonstrate that environmental fluctuation can produce coexistence when environmental variables, standing crops, assimilation efficiencies, primary productivity, utilization rates, and respiration rates are comparable to a tropical grassland, and an oligotrophic temperate lake. The sensitivity of model solutions to functional variations of the component species may be rapidly and accurately calculated. This allows the identification and estimation of unknown species functional responses from time series data of biomasses and a measured environmental variable. Unknown functions of an environmental variable are approximated by a Tchebycheff polynomial expansion in that variable. Unknown coefficients of these expansions are the parameters of the model. These parameters are determined by the unconstrained minimization of the squared deviations of the logarithm of biomass observations and model differential equation solution using a Quasi-Newton algorithm. This least squares estimator was applied to a one year biomass time series of four zooplankton grazers, phytoplankton, and average lake temperature of a small oligotrophic lake. Application of the model to this grazer zooplankton community gives evidence of partial stabilization due to environmental fluctuation in a natural community. It is concluded that environmental variation, which is often assumed on theoretical grounds to be destabilizing, should rather be considered as one of the bases of community persistence. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Interconnects constitute a dominant source of circuit delay for modern chip designs. The variations of critical dimensions in modern VLSI technologies lead to variability in interconnect performance that must be fully accounted for in timing verification. However, handling a multitude of inter-die/intra-die variations and assessing their impacts on circuit performance can dramatically complicate the timing analysis. In this thesis, three practical interconnect delay and slew analysis methods are presented to facilitate efficient evaluation of wire performance variability. The first method is described in detail in Chapter III. It harnesses a collection of computationally efficient procedures and closed-form formulas. By doing so, process variations are directly mapped into the variability of the output delay and slew. This method can provide the closed-form formulas of the output delay and slew at any sink node of the interconnect nets fully parameterized, in-process variations. The second method is based on adjoint sensitivity analysis and driving point model. It constructs the driving point model of the driver which drives the interconnect net by using the adjoint sensitivity analysis method. Then the driving point model can be propagated through the interconnect network by using the first method to obtain the closedform formulas of the output delay and slew. The third method is the generalized second-order adjoint sensitivity analysis. We give the mathematical derivation of this method in Chapter V. The theoretical value of this method is it can not only handle this particular variational interconnect delay and slew analysis, but it also provides an avenue for automatical linear network analysis and optimization. The proposed methods not only provide statistical performance evaluations of the interconnect network under analysis but also produce delay and slew expressions parameterized in the underlying process variations in a quadratic parametric form. Experimental results show that superior accuracy can be achieved by our proposed methods.

Haydn¡¦s variation play an very importment role in the development of variations. Haydn not only continue C.P.E. Bach¡¦s variation technique, but also has innovations both in variation form and variation¡¦s technique. Haydn writes twenty-one keyboard variations, most of them are written as melodic variation with fixed harmony. The form of variation of Haydn can be divided into four types- strophic variations, rondon variations, alternating variations and ABA variations. All these variations are based on subject¡¦s recurrence, and the theme contrast to the subject. Strophic variations was the type that haydn most often use. Haydn¡¦s keyboard variation can be divided into independent keyboard variations and variation¡¦s movement in the keyboard sonata. Haydn have five independent keyboard variations, most of them were sectional variations. There are sixteen variation¡¦s movements, most of them are continuous variations. Most of the time, they are place in the finale. The subject in Haydn¡¦s keyboard variation all have two sections, which divided by repeat sign. Haydn seems prefer using up-beat and dotted rhythm in his subject. Beside writing variations in Allegro movement, he also writes variation in Adagio and Andante movement. In this thesis includes four chapters. The first chapter is to discuss variaion¡¦s development in the classical period. The second chapter is to sort out and analyze the type of Haydn¡¦s keyboard variations. The third chapter is to analyze the variation technique in Haydn¡¦s keyboard variations. The fourth chapter is conclusion.

The eastern subterranean termite, Reticulitermes flavipes, is the most widely dispersed termite in North America. The genus Reticulitermes spp. is responsible for 80% of total termite damage caused to urban structures each year. Little is known about the genetic structure of termites, particularly at the colony level. Evidence for what genetically defines a termite colony is a hotly debated topic in current literature due to the implications such findings would have regarding current lawsuits against pest control operations. Information on termite genetic structure is sparse. In this study, the genetic variation and gene flow among Texas populations of R. flavipes at the statewide level and city level was examined. A 324-337 base pairs segment of the mtDNA, AT-rich region was a polymerase chain reaction amplified from 104 different termite specimens from 12 Texas cities. The DNA extracts were then subjected to PCR amplification using specific primers and it was then sequenced. Using the sequence data and appropriate statistical measures it was found that, at the statewide level, nucleotide and haplotypic diversity is low. Gene flow was found to be low on a statewide basis. At the city level nucleotide and haplotypic diversity was high. The findings of this study provide insights into termite genetic structure.

No description available.

Inaug.-Diss.--Leipzig. / Vita. "Literatur": p. [5]-11.

Silozi came into existence in the early 1800s when Sikololo speakers (Makololo) from South Africa came in contact with the Siluyana speakers (Luyi) in Barotseland. Today the language is spoken by over 700 000 people in Zambia, Namibia, Botswana, Angola and Zimbabwe collectively. Of the wealth of scholarship on the Malozi and their language, most focused on development and structure. Silozi dialect variation is yet to be explored in depth. This is a study of dialect variation in cross-border Silozi. The focus is on the lexicon and the morphosyntactic structures of the Silozi varieties spoken in the towns of Katima Mulilo (Namibia) and Mongu (Zambia). As an example of mixed-methods research, the data collection was conducted using the language documentation and description approach (see Lüpke, 2010; Himmelman, 1998). The data comprised of lexicon and sample sentences elicited via structured interviews from 70 participants. In addition, metalinguistic questions were used to collect information on essential language use patterns during data analysis. The findings confirmed that Silozi is the official language in Katima Mulilo, but Chisubiya and Chifwe are the dominant lingua francas. Contrastingly, in Mongu, Silozi is the main Bantu language, with others spoken minimally. A consequence of this is that the Katima Mulilo variety contained more lexical borrowings from other Bantu languages compared to Mongu. However, both varieties borrowed more lexicon from English than from the Bantu languages. Morphosyntactically, the Katima Mulilo variety contains grammatical features from Chisubiya that are not present in the Mongu variety. Chisubiya plays a central role in the differences that emerge between the two varieties. Overall, the Mongu variety appeared to be more stable and less susceptible to change. This thesis thus illustrates that there is nuanced variation in cross-border Silozi. Language contact and migration are shown to have been significant factors in ongoing language change in cross-border dialects.

No description available.

Les variations de nombre de copies (CNVs) sont des séquences supérieures à 1kb ayant subi une délétion, une duplication ou une inversion de fragments d'ADNs et sont présents avec une fréquence de 12% dans le génoe humain. Leur caractérisation ainsi que leur association dans les maladies complexes sont, à ce jour, en plein essor. Nous avons donc entrepris l'étude des CNVs de gènes candidats dans les familles de patients atteints de polyarthrite rhumatoïde (PR) en utilisant plusieurs outils de biologie moléculaire. Les CNVs de quatre gènes candidats (GSTMI, GSTT1, FCGR3B et CCL3L1) ont été investigués par PCR classique, qPCR ou Droplet Digital PCR (ddPCR). Mais très vite, la PCR classique a montré qu'elle n'est pas applicable à tous les gènes et que la qPCR était peu sensible et reproductible. Par contre, grâce à la ddPCR, nous avons tout d'abord pu quantifier avec précision les CNVs des gènes GSTM1, FCGR3B et CCL3L1. Par la suite, nous avons pu identifier les génotypes en nombre de copies pour le gène GSTM1 et mettre en évidence une duplication en tandem qui a été confirmée par une Lone Range PCR. La transmission des CNVs au sein des familles étudiées nous a ensuite permis d'identifier tous les génotypes en nombre de copies du gène FCGR3B et certains génotypes du gène CCL3LI. Des événements de recombinaison de novo ont été mis en évidence pour le gène FCGR3B ainsi que des duplications en tandem transmises des parents aux patients pour les trois gènes investigués par ddPCR. Aucune association n'a été mise en évidence entre la PR et les CNVs des quatre gènes candidats. Néanmoins, une transmission préférentielle de la délétion du gène GSTT1 a été mise en évidence, après stratification dans le sous-groupe de patients séropositifs pour le facteur rhumatoïde. Des tendances non significatives ont été observées dans les sous-groupes de cas index avec un âge de début de la maladie inférieur à 40 ans, avec présence de modules (pour le gêne GSTM1), et avec la présence d'auto-anticorps (pur les gènes FCGR3B et CCL3L1). En conclusion, le développement de l'utilisation d'une technologie de pointe et l'accès à des échantillons familiaux sont des atouts indispensables pour caractériser les variants génomiques de nombre de copies, facteurs de risque potentiels des maladies complexes. / Copy number variations (CNVs) are sequences up to 1kb resulting from deletion, duplication and inversion of DNA regions ans are present with a frequency of 12% in the human genome. CNVs characterization and association to complex diseases are still subjects of controversies. We then enhanced the study of CNV's for candidate genes in rhemuatoid arthritis (RA) families, with different methodologies. CNVs of our candidate genes (GSTM1, GSTT1, FCGR3B et CCL3L1) were investigated with standard PCR, quantitative PCR (qPCR) or with Droplet Digital PCR (ddPCR). First we found that standard PCR was not applicable for all genes and that the qPCR was not sensitive and reproductible for CNVs quantification. Second, the ddPCR methodology allowed us to quantify CNVs of GSTM1, FCGR3B, and CCL3L1 with high resolution and to characterize copy number genotypes og GSTM1 gene, leading to the identification of tandem duplicated copies. A long range PCR confirmed this result. CNVs transmission in families allowed the identification of all copy number genotypes for FCGR3B gene and some of CCL3L1 with high resolution and to characterize copy numbers genotypes of GSTM1 gene, leading to the identification of tandem duplicated copies. A long Range PCR confirmed this result. CNVs transmission in families allowed the identification of all copy number genotypes for FCGR3B gene and some of CCL3L1 genotypes. De novo recombination events were highllighted for FCGR3B gene and transmission of the duplication from one parent to the offspring was observed for all genes characterized by ddPCR. No association between RA and candidate genes CNVs was found, but after stratification, we observed a significant preferential transmission of GSTT1 deletion in the subgroup of patients seropositive for rheumatoid factor. We also showed a non-significant tendency in the subgroups of patient with an age at onset inferior to 40 years, with presence of nodules (for GSTM1 gene), and with presence of auto-antibodies (for FCGR3B and CCL3L1 gene). In conclusion, digital PCR is currently the most adequate methodology to accurately genotype CNVs. Analysis of familial sample leads to the identification of duplication events and to the characterization of genotypes, essential for CNVs association in complex diseases.