This thesis presents a detailed analysis of the bRAPID (burnup for RAPID – Real Time Analysis for Particle transport and In-situ Detection) code system, and the implementation and validation of two new algorithms for improved burnup simulation. bRAPID is a fuel burnup algorithm capable of performing full core 3D assembly-wise burnup calculations in real time, through its use of the RAPID Fission Matrix methodology. A study into the effect of time step resolution on isotopic composition in Monte Carlo burnup calculations is presented to provide recommendations for time step scheme development in bRAPID. Two novel algorithms are implemented into bRAPID, which address: i) the generation of time-dependent correction factors for the fission density distribution in boundary nuclear fuel assemblies within a reactor core; ii) the calculation of pin-wise burnup distributions and isotopic concentrations. Time step resolution analysis shows that a variable time step scheme, developed to accurately characterize important isotope evolution, can be used to optimize burnup calculations and minimize computation time. The two new algorithms have been benchmarked against the Monte Carlo code system Serpent. Results indicate that the time-dependent boundary correction algorithm improves fission density distribution calculations by including a more detailed representation of boundary physics. The pin-wise burnup algorithm expands bRAPID capabilities to provide material composition data at the pin level, with accuracy comparable to the reference calculation. In addition, wall-clock time analyses show that burnup calculations performed using bRAPID with these novel algorithms require a fraction of the time of Serpent. / Master of Science / Fuel burnup modeling is an important aspect of nuclear reactor design that provides information about the energy extracted (called burnup) and isotopes created or used in the fuel of a reactor over time. A reactor core is a collection of fuel assemblies, and assemblies are simply a bundle of fuel pins, which contain nuclear fuel such as Uranium. The desire for accurate and fast computer codes to calculate fuel burnup rises each year as engineers working in reactor core design seek to arrange fuel assemblies in an optimal pattern to extract the most energy. State of the art burnup codes exist, however they have certain limitations due to their underlying methodologies. To satisfy this need, the bRAPID algorithm was developed by the Virginia Tech Transport Theory Group (VT³G). bRAPID is a new methodology capable of performing full core fuel burnup calculations in real time. bRAPID is able to calculate the criticality and burnup distribution of a reactor orders of magnitude faster than comparable algorithms, while addressing many of the shortcomings seen in other burnup codes. In this thesis, studies of standard burnup codes are conducted in order to aid in bRAPID analysis: first in the form of a detailed study of the reference Monte Carlo model used in this thesis, and secondly in an investigation of the effect of time step selection – or the time intervals used in burnup calculations – on isotope concentration. Both of these studies are conducted using the benchmark code system, Serpent, with the latter study providing useful insight that can be used for bRAPID database development. This thesis then presents two new algorithms for bRAPID that expand its capability and improve performance. First, an algorithm to more accurately simulate the boundary regions of the core – called the time dependent boundary correction algorithm – is presented and benchmarked. Next, an algorithm to expand bRAPID capability from assembly-wise to pin-wise burnup calculations is implemented and tested. These two algorithms are benchmarked against the Serpent Monte Carlo based burnup code.

"Nearer Than the Eye" est un court roman (147 pages) en anglais dont le sujet est une famille québécoise anglo-francophone demeurant à Québec pendant les années 1990. Une mère dévote a des visions d'anges et dialogue avec une relique qu'elle porte dans sa poche, tout en s'inquiètant de sa sœur toxicomane et de sa fille qui sombre dans un monde de sexe et de la drogue. La femme s'en culpabilise à cause d'un secret enfoui dans son passé, avec lequel elle n'a pas encore fait la paix. En deuxième partie, une dissertation commente la façon dont la culture religieuse québécoise et la foi catholique influencent mon écriture en comparant mon roman avec Wise Blood de Flannery O'Connor, notamment en examinant sa pensée sur la fiction catholique. Je fais référence aux éléments de la grotesque et du réalisme magique applicables aux deux ouvrages, tout en faisant un lien avec la théologie catholique.

Adequate supply and availability of nitrogen (N) is a major factor hindering successful revegetation of reclaimed surface mines. Because topsoils are often unrecoverable, “topsoil substitutes”, made up of overburden materials devoid of N, are often used on reclaimed surfaces. Four replications of seven surface treatments were applied to 12 m² plots of 2:1 sandstone:siltstone material on a reclaimed coal surface mine in Wise Co., VA: 1) fertilizer (168 kg/ha N, 147 kg/ha P, and 139 kg/ha K), 2) limed (7.8 Mg/ha), fertilized topsoil (30 cm deep), 3) 112 Mg/ha sawdust + fertilizer + 336 kg/ha slow-release N, and 4-7) lime-treated municipal sewage sludge at rates of 22, 56, 112, and 224 Mg/ha. Nitrogen availability after 40 mo (as determined by aerobic and anaerobic incubations) in sawdust- and sludge-amended soils was two to 20 times higher than in fertilized and topsoil-amended soils. Moisture holding capacity was nearly twice as high in sawdust-amended soils as in all other treatments. Soil nitrate (NO₃⁻) levels (0-20 cm layer) in excess of 75 μg/g were detected in the 112 and 224 Mg/ha sludge plots 28 mo after application. Stem volumes of three-year-old pitch X loblolly pines (<i>Pinus rigida</i> X <i>taeda</i>) were four times larger in soils amended with sawdust + slow-release N and were twice as large in soils amended with 22 and 56 Mg/ha sludge compared to fertilized-only seedlings. Increased seedling mortality was observed in the 112 and 224 Mg/ha sludge treatments, possibly due to high soluble salt levels and/or manganese deficiencies. The availability of N from sawdust + slow-release N or sludge (≤ 56 Mg/ha) is better than that of inorganic fertilizer for sustained tree growth. These amendments are recommended for reclamation to the extent that they are economically available. / M.S.

Yes / We examine whether the inflation rates of the countries that pursueinflation targeting policies have converged as opposed to the expe-rience of the OECD non-inflation targeters. Using a methodologyintroduced by Pesaran (2007a), we examine the stationarity prop-erties of the inflation differentials. This approach has the advantageof avoiding setting arbitrarily a specific country as the benchmarkeconomy. Our results indicate that the inflation rates converge irre-spective of the monetary policy framework.

This problem consists of classifying the four major pastures of the McKamy ranch into McConnell's four categories, by means of examinations based on these qualities and characteristics.

Comme dans la quasi-totalité des pays, les autorités éducatives en Syrie ont des préoccupations quant à l’amélioration de la qualité de l’enseignement et quant aux réformes qu’elles cherchent à mettre en œuvre pour donner aux enseignants la possibilité d’acquérir les nouvelles connaissances et compétences avant et une fois qu’ils exercent leur métier, surtout dans le contexte du changement économique et social de grande ampleur que vit le monde aujourd’hui. La complexification du contexte éducatif a amené les autorités pédagogiques syriennes à accorder une attention particulière aux programmes de la formation initiale et continuée des enseignants. Pour juger de l’efficacité des programmes de formation continue qui existent actuellement en Syrie, la présente thèse s’est fixée comme objectif d’analyser les impacts de ces programmes sur l’amélioration des compétences professionnelles des enseignants. Il ressort des analyses que les programmes de formation continue suivis en Syrie sont positivement corrélés à l’ensemble des compétences professionnelles des enseignants de l’échantillon. Les programmes de formation continue génèrent, d’après les estimations des membres de l’échantillon, une grande différence dans le niveau général de leur travail professionnel. Les analyses ont abouti également à la conclusion que d’autres facteurs jouent dans l’amélioration des compétences des enseignants. L’indicateur de la formation continue est donc statistiquement plus significatif si cette dernière s’adhère aux autres facteurs. / As in nearly all countries, educational authorities in Syria have concerns about improving the quality of education and about there forms they seek to implement to give teachers the opportunity to acquire new knowledge and skills before and once they start teaching, especially in the context of economic and social change of the magnitude the world lives today. The complexity of the educational context has led the Syrian educational authorities to pay particular attention to programs for initial and continuous training of teachers.To assess the effectiveness of continuous training programs that currently exist in Syria, this thesis has set as its objective to analyze the impact of these programs on the improvement of professional skills of teachers. The statistical analysis shows that continuous training programs followed in Syria are positively correlated with all the professional skills of teachers in the sample. The continuous training programs generate, according to the estimates of the sample, a big difference in the overall level of their professional work. The analysis concludes that other factors play also a role in improving the skills of teachers. The indicator of continuous training programs is statistically significant if it adheres to other factors.

No description available.

This master thesis was performed in order to investigate arsenic stabilization in step-wise amended soil. Object of the work - soil which taken from the former wood impregnation industrial site in Forsmo, Sweden. It is contaminated with chromate-zinc-arsenate (CZA). Method of the work - three different amendments were used: zerovalent iron (Fe), fly-ash (FA) and peat (P). The test was performed in three weeks. During the first week, four mixtures (with each single additive and with all together) and blank soil was observed. During the second and third weeks test was performed step-wise adding amendments to soil+Fe mixture. Moisture was kept constant all the time. After each week extractions were made and later investigated by doing electrical conductivity, redox potential and pH tests. For elemental composition ICP-OES analysis was performed. The results of the work - the best result to stabilize arsenic were achieved by adding single iron. Stabilisation using iron, fly-ashes and peat elevated As leaching compared to non-amended soil. Step-wise amendment did not have a significant difference from single amelioration neither to arsenic, nor to other heavy metals investigated. / Darbo tikslas - įvertinti pakopinės stabilizacijos poveikį arseno bei kitų sunkiųjų metalų (SM) judrumui užterštame dirvožemyje. Darbo objektas - chromuotu cinko arsenatu užterštas dirvožemis, paimtas iš buvusios medienos apdirbimo aikštelės Forsmo vietovėje, Švedijoje. Darbo metodika - tyrimui buvo naudoti trejopi priedai: geležis (0), lakieji pelenai ir durpės. Tyrimas atliktas per tris savaites. Pirmosios savaitės metu buvo stebimi keturi dirvožemio ir jo priedų mišiniai bei kontrolinis dirvožemio mėginys. Vėliau dirvožemio ir geležies mišinys buvo pakopiniu būdu papildomas lakiaisiais pelenaisi ir durpėmis. Iš visų mišinių padarytos ištraukos ir jose matuojamas elektrinis laidumas, oksidacijos-redukcijos potencialas, pH; atlikta elementinė analizė. Darbo rezultatai - efektyviausiai arseną stabilizuoja geležis. Stabilizacija, naudojant lakiuosius pelenus ir durpes, padidino arseno išsiplovimą iš dirvožemio, lyginant su kontroliniu dirvožemio mėginiu. Pakopinė stabilizacija nebuvo efektyvesnė už vienkartinę stabilizaciją nei arseno, nei kitų tirtų sunkiųjų metalų atžvilgiu.

Au cours de ces dernières années, le problème de la recherche de requêtes fréquentes dans les bases de données est un problème qui a suscité de nombreuses recherches. En effet, beaucoup de motifs intéressants comme les règles d'association, des dépendances fonctionnelles exactes ou approximatives, des dépendances fonctionnelles conditionnelles exactes ou approximatives peuvent être découverts simplement, contrairement au méthodes classiques qui requièrent plusieurs transformations de la base pour extraire de tels motifs.Cependant, le problème de la recherche de requêtes fréquentes dans les bases de données relationnelles est un problème difficile car, d'une part l'espace de recherche est très grand (puisque égal à l'ensemble de toutes les requêtes pouvant être posées sur une base de données), et d'autre part, savoir si deux requêtes sont équivalentes (donc engendrant les calculs de support redondants) est un problème NP-Complet.Dans cette thèse, nous portons notre attention sur les requêtes de type projection-selection-jointure, et nous supposons que la base de données est définie selon un schéma étoile. Sous ces hypothèses, nous définissons une relation de pré-ordre (≼) entre les requêtes et nous montrons que :1. La mesure de support est anti-monotone par rapport à ≼, et2. En définissant, q ≡ q′ si et seulement si q ≼ q′ et q′ ≼ q, alors toutes les requêtes d'une même classe d'équivalence ont même support.Les principales contributions de cette thèse sont, d'une part d'étudier formellement les propriétés du pré-ordre et de la relation d'équivalence ci-dessus, et d'autre part, de proposer un algorithme par niveau de type Apriori pour rechercher l'ensemble des requêtes fréquentes d'une base de données définie sur un schéma étoile. De plus, cet algorithme a été implémenté et les expérimentations que nous avons réalisées montrent que, selon notre approche, le temps de calcul des requêtes fréquentes dans une base de données définie sur un schéma étoile reste acceptable, y compris dans le cas de grandes tables de faits. / The problem of mining frequent queries in a database has motivated many research efforts during the last two decades. This is so because many interesting patterns, such as association rules, exact or approximative functional dependencies and exact or approximative conditional functional dependencies can be easily retrieved, which is not possible using standard techniques.However, the problem mining frequent queries in a relational database is not easy because, on the one hand, the size of the search space is huge (because encompassing all possible queries that can be addressed to a given database), and on the other hand, testing whether two queries are equivalent (which entails redundant support computations) is NP-Complete.In this thesis, we focus on projection-selection-join queries, assuming that the database is defined over a star schema. In this setting, we define a pre-ordering (≼) between queries and we prove the following basic properties:1. The support measure is anti-monotonic with respect to ≼, and2. Defining q ≡ q′ if and only if q ≼ q′ and q′ ≼ q, all equivalent queries have the same support.The main contributions of the thesis are, on the one hand to formally sudy properties of the pre-ordering and the equivalence relation mentioned above, and on the other hand, to prose a levewise, Apriori like algorithm for the computation of all frequent queries in a relational database defined over a star schema. Moreover, this algorithm has been implemented and the reported experiments show that, in our approach, runtime is acceptable, even in the case of large fact tables.

Orientador: John Fredy Franco Baquero / Resumo: O planejamento bem-sucedido de redes de distribuição requer uma metodologia que inclua um modelo de rede preciso que considere não apenas os custos econômicos, mas também os custos associados à confiabilidade do sistema. Considerando estas duas características essenciais, esta tese propõe modelos matemáticos que permitam incluir a avaliação da confiabilidade dentro do problema do planejamento de expansão de sistemas de distribuição com múltiplos estágios, visando expandir os ativos de rede (ramos e subestações) e minimizar os custos de confiabilidade do sistema. Em relação às características da rede, o modelo de planejamento proposto utiliza um fluxo de potência AC não-linear e não convexo, que é convertido em um problema convexo usando reformulação cônica, técnicas de linearização por partes, com o intuito de obter tratabilidade computacional usando técnicas clássicas de otimização. Além disso, a avaliação de confiabilidade convencional baseada em simulação é implementada de forma equivalente por meio de expressões algébricas dentro do modelo matemático. Vários casos de estudo são usados ​​para demostrar a eficácia da metodologia de planejamento proposta. / Abstract: Successful planning of distribution networks requires a methodology that includes an accurate network model that considers not only the economic costs but also the costs associated with system reliability. Considering these two essential characteristics, this thesis proposes mathematical models that include reliability assessment within multi-stage expansion planning problem of distribution systems, aiming at expanding network assets (branches and substations) and minimizing reliability costs of the system. In relation to the network characteristics, the proposed planning model uses a non-convex nonlinear AC power flow, which is converted into a convex problem using conic reformulation and piece-wise linearization, to obtain the computational treatability using classical optimization techniques. In addition, conventional simulation-based reliability assessment is implemented equivalently through algebraic expressions. Several benchmarks are used to demonstrate the effectiveness of the proposed planning methodology. / Doutor