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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Développement d’un outil physique orienté conception pour la simulation des excursions de puissance non protégée dans un RNR-Na / Development of a design-oriented tool for unprotected power excursion simulations in a SFR

Herbreteau, Kevin 24 September 2018 (has links)
Ce travail de thèse se place dans le contexte des études d’accidents graves sur les réacteurs à neutrons rapides à caloporteur sodium. Dans le cadre de la démarche de conception et de sûreté, tous les types d’accidents doivent être étudiés afin d’assurer l’exhaustivité de l’analyse de sûreté, en traitant la variabilité des scénarios accidentels et en quantifiant les marges de sûreté. Pour cela, des outils physiques sont développés pour être couplés à des techniques avancées de statistique permettant de répondre rapidement et quantitativement aux questions relatives à la conception du réacteur vis-à-vis des conséquences d’un accident grave et de prendre en compte des incertitudes et de la variabilité des scénarios accidentels. La mise au point de l’outil physique OCARINa (Outil de Calcul analytique Rapide pour les Insertions de réactivité dans un RNR-Na) dédié à la phase primaire du transitoire d’insertion de réactivité non protégée UTOP (Unprotected Transient OverPower) a ainsi fait l’objet de cette thèse. Les travaux ont porté sur l’identification des phénomènes physiques prépondérants, leur modélisation (thermique et thermomécanique), et une contribution à la validation expérimentale et numérique. Enfin, une application de l’intérêt de cet outil a été réalisée à partir de deux études BEPU (Best-Estimate Plus Uncertainties). Elle a permis d’identifier les paramètres les plus influents sur la réponse de l’outil, et de quantifier leur impact vis-à-vis des résultats expérimentaux. / Within the framework of the Generation IV Sodium-cooled Fast Reactor R&D French program, a new physico-statistical approach is currently followed by the CEA for accident transient calculations in complement to the reference mechanistic codes. This approach involves a fast-running description of extended accident sequences coupling physical models for the main phenomena to advanced statistical analysis techniques. A large number of simulations may be performed in a reasonable computational time while describing all the possible bifurcations of the accident transient. In this context, this PhD work deals with the development (models and results assessment) of the physical tool dedicated to the primary phase of the Unprotected Transient OverPower accident called OCARINa (Outil de Calcul analytique Rapide pour les Insertions de réactivité dans un RNR-Na). The accident main phenomena, their modelling (thermal and thermomechanical models) and a contribution to the experimental and numerical validation are described. Finally a demonstration of BEPU studies has been done, resulting in the identification and the impact quantification of the more influent uncertain parameters on experimental results.
2

Near infra red spectroscopy as a multivariate process analytical tool for predicting pharmaceutical co-crystal concentration

Wood, Clive, Alwati, Abdolati, Halsey, S.A., Gough, Timothy D., Brown, Elaine C., Kelly, Adrian L., Paradkar, Anant R 07 June 2016 (has links)
Yes / The use of near infra red spectroscopy to predict the concentration of two pharmaceutical co-crystals; 1:1 ibuprofen – nicotinamide (IBU-NIC) and 1:1 carbamazepine – nicotinamide (CBZ-NIC) has been evaluated. A Partial Least Squares (PLS) regression model was developed for both co-crystal pairs using sets of standard samples to create calibration and validation data sets with which to build and validate the models. Parameters such as the root mean square error of calibration (RMSEC), root mean square error of prediction (RMSEP) and correlation coefficient were used to assess the accuracy and linearity of the models. Accurate PLS regression models were created for both co-crystal pairs which can be used to predict the co-crystal concentration in a powder mixture of the co-crystal and the active pharmaceutical ingredient (API). The IBU-NIC model had smaller errors than the CBZ-NIC model, possibly due to the complex CBZ-NIC spectra which could reflect the different arrangement of hydrogen bonding associated with the co-crystal compared to the IBU-NIC co-crystal. These results suggest that NIR spectroscopy can be used as a PAT tool during a variety of pharmaceutical co-crystal manufacturing methods and the presented data will facilitate future offline and in-line NIR studies involving pharmaceutical co-crystals.
3

Intern materialhantering på Fläkt Woods AB / Internal material handling at Fläkt Woods AB

Severinsson, Marcus, Karlsson, Andreas January 2012 (has links)
Intern materialhantering är ett ofta bortglömt område inom logistik, ett ämnesområde som annars i takt med den snabba och globala utvecklingen har fått ökad uppmärksamhet de senaste åren. I detta examensarbete studeras den interna materialhanteringen på Fläkt Woods ABs fabrik i Jönköping begränsat till flödet mellan godsmottagning och slutmontering. Syftet med fallstudien är att undersöka vilka problem som finns med den nuvarande interna materialhanteringen samt ge förbättringsförslag för hur den skulle kunna utvecklas för att minimera antalet produktionstopp orsakade av materialbrist. Studien har en abduktiv ansats där datainsamling genom dokumentation, observationer och intervjuer ligger till grund för en flödeskartläggning av tre produktgrupper som företaget bedömt vara mest intressanta att studera. Utifrån flödet identifieras möjliga problem och med hjälp av ett analytiskt ramverk klassificeras dessa för att urskilja de problem som leder till produktionsstopp. Studien visar att dessa handlar om att komponenter av någon anledning är felaktiga/skadade, lagras in/plockas på ett felaktigt sätt eller att det sker felaktigheter vid godsmottagning med avseende på registrering och sortering. Genomförda litteraturstudier ligger till grund för ett teoretiskt ramverk innehållande principer som bör tas i beaktning vid arbetet med intern materialhantering. Ramverket är en utgångspunkt för de förbättringsförslag som tas fram för att lösa de problem som bedöms orsaka produktionsstopp. Övergripande sett hamnar förbättrings­­förslagen inom tre skilda områden. Det första området berör problem orsakade av mänskliga faktorer vilka kan minimeras genom ökad motivation, produktkunskap och helhets­förståelse. Område nummer två täcker fysisk förflyttning av material samt registrering av detta i affärssystemet vilket bör ske på ett standardiserat och mer säkert sätt. Det tredje området innefattar ett behov av utökad mätning och uppföljning av de problem som uppstår i flödet för att få ökad kontroll över vad som sker. Studenterna rekommenderar företaget att, förutom att implementera föreslagna förbättringar, också studera det teoretiska ramverket för att kunna tillämpa detta på ytterligare problem som studien har identifierat men som ligger utanför studiens omfång. / Internal material handling is an area within logistics that receive little attention. Logistics on the other hand has received increased attention in recent years due to the fast and global growth of markets. The aim for this report is to study the internal material handling at Fläkt Woods AB’s factory in Jönköping, Sweden. The study is limited to include activities from receiving goods until the start of final assembly. The purpose with this case study is to identify potential problem within the current setup of the internal material handling system and provide suggestions for improvements in order to minimize downtime in production caused by lack of material. Based on an abductive approach, the data collection performed via documents, observations and interviews lays the foundation for the compilation of a number of flowcharts. These flowcharts describe the flow for three separate product groups which the company previously has identified as most interesting to map. With the flowcharts as a starting point potential problems are identified and, with the use of an own-composed analytical framework, also classified in order to sort out problems that are likely to cause downtime in production. The study states that these problems originate from damaged/defective components, incorrect storing/picking or occur due to errors when recording and sorting newly arrived goods. Literature studies are the basis for a theoretical framework containing a number of principles that should be taken into consideration when handling material internally. This framework is the base on which the presented suggestions for improvements rely. The suggestions can be divided into three separate areas. Problems caused by human factors can be minimized by increased motivation, increased knowledge and a more comprehensive view within the workforce. All kinds of physical movement along with registration in the ERP-system should be conducted in a more standardized and secure way. A need of increased measuring and monitoring has also become evident in order to increase control over different types of undesirable events. Beside implementing the proposed suggestions for improvement the students also advice the company to study the theoretical framework in order to be able to apply it on other problems. This study identifies quite a few other problems, but due to the scope of the study they are not further analyzed.
4

Environmentální gramotnost žáků 2. stupně základní školy v České republice, Slovensku, Polsku a Německu / Environmental Literacy of Second Grade's Pupils at Primary School in the Czech Republic, Slovakia, Poland and Germany

Svobodová, Silvie January 2021 (has links)
Environmental Literacy of ISCED 2 Pupils in the Czech Republic, Slovakia, Poland and Germany Mgr. Ing. Silvie Svobodová ABSTRACT The concept of environmental literacy is based primarily on the principles of environmental education. It is a measure of environmental knowledge, attitudes, sensitivity and environmentally responsible behavior. It represents a relatively broad multidimensional construct, which can be summarized into three main dimensions (cognitive, affective and conative). This dissertation is focused on the environmental literacy of ISCED 2 pupils in the Czech Republic and selected Central European countries. The main contribution of the work lies in the construction and verification of a sophisticated authorial analytical tool for comprehensive testing of environmental literacy and its application in the Czech Republic, Slovakia, Poland, Austria and Germany. The tool is based on a range of tools established and published abroad, the applicability of which in the Czech environment has been verified, namely the Middle School Environmental Literacy Survey and 2 Major Environmental Values. The research analyzed the relationship between the dimensions of environmental literacy and the identified significant determinants that can fundamentally predict the level of environmental literacy, in the...
5

Energy Storage System Requirements For Shipboard Power Systems Supplying Pulsed Power Loads

Duvoor, Prashanth 15 December 2007 (has links)
Energy storage systems will likely be needed for future shipboard power systems that supply loads with high power variability such as pulsed power loads. The power generation in shipboard power systems may not be sufficient to satisfy the energy demands of the pulsed power load systems operating in conjunction with other ship service loads. Two fundamental items in evaluating the requirements of an energy storage system are the energy storage capacity and the ratings of the power conversion equipment that interfaces the energy device to the power system. The supply current of pulsed power load systems is aperiodic and cannot be described in terms of active power. Also, the RMS value and thus apparent power are only defined for periodic quantities. Therefore traditional methods of rating power equipment cannot be used. This thesis describes an approach to determine the ratings of an energy storage interface and the energy storage capacity of an energy storage device as a function of load and supply parameters. The results obtained using the proposed approach are validated with the results obtained from the simulation model of the generator supplying a pulsed power load in conjunction with an energy storage system. The energy storage system requirements for various pulsed power load profiles are obtained using the proposed approach. The method used for determining the ratings of an energy storage system utilizes an orthogonal decomposition of pulsed power load system supply current evaluated within a sliding window. The signals obtained from the decomposition are also useful in generating the control reference signals for the energy storage interface. Although the approach and methods are focused on a particular structure of the pulsed power load system, they may be generalized for use in any type of configuration of a pulsed power load system.
6

Geology as a Georegional Influence on Quercus Fagaceae Distribution in Denton and Coke Counties of Central and North Central Texas and Choctaw County of Southeastern Oklahoma, Using GIS as an Analytical Tool.

Maxey, George F. 12 1900 (has links)
This study elucidates the underlying relationships for the distribution of oak landcover on bedrock and soil orders in two counties in Texas and one in Oklahoma. ESRI's ArcGis and ArcMap was used to create surface maps for Denton and Coke Counties, Texas and Choctaw County, Oklahoma. Attribute tables generated in GIS were exported into a spreadsheet software program and frequency tables were created for every formation and soil order in the tri-county research area. The results were both a visual and numeric distribution of oaks in the transition area between the eastern hardwood forests and the Great Plains. Oak distributions are changing on this transition area of the South Central Plains. The sandy Woodbine and Antlers formations traditionally associated with the largest oak distribution are carrying oak coverage of approximately 31-32% in Choctaw and Denton Counties. The calcareous Blackland and Grand Prairies are traditionally associated with treeless grasslands, but are now carrying oak and other tree landcover up to 18.9%. Human intervention, including the establishment of artificial, political and social boundaries, urbanization, farming and fire control have altered the natural distribution of oaks and other landcover of this unique georegion.
7

Développement d'un outil de pré dimensionnement de structures sandwich soumises à des impacts à vitesse intermédiaire

Mavel, Sébastien 04 October 2012 (has links)
Dans le cadre du développement d’un outil semi-analytique de pré-dimensionnement de structures sandwich soumises à des impacts à vitesse intermédiaire (<20m.s-1), nous proposons la détermination d’une solution efficace, basée sur les séries de Fourier avec des conditions aux limites générales. Les équations gouvernantes qui permettent de décrire la réponse transitoire élastique de plaques stratifiées orthotropes avec prise en compte d’une loi non linéaire de contact hertzien sont développées en utilisant un schéma de discrétisation temporelle explicite. Pour les conditions aux limites générales, la solution en séries de Fourier est complétée par une série mixte de polynômes-cosinus, qui permet d’aboutir à la solution, tout en permettant à la série de satisfaire les équations d’équilibres ainsi que les conditions limites, de façon exacte en augmentant le nombre de termes de la série. Afin de tenir compte des phénomènes physiques locaux lors de l’impact de structure sandwich, la plasticité et la rupture locale de la plaque anti-perforation sont introduites dans une formulation modifiée du contact de Hertz et l’écrasement de l’âme du sandwich est ajouté dans l’équation d’équilibre du projectile. Les solutions obtenues par cette méthode sont en accord avec les résultats par modélisation éléments finis de plaques composites multicouches impactées par un projectile. Une campagne expérimentale d’impact de type « box corner » sur des plaques sandwich de 1m², a servi de référence expérimentale et permis la validation de ce modèle complet. Finalement, le couplage de ce modèle à un optimiseur basé sur les techniques de plans d’expériences et de surfaces de réponses (métamodèles), nous a permis de choisir la meilleure structure d’absorption d’énergie (matériaux et géométrie) pour des structures plaques soumises à des impacts de 7kJ. Un test sur un véhicule réel avec la configuration structurelle choisie, nous a permis de valider l’outil final de pré-dimensionnement et de confirmer la qualité des résultats numériques obtenus par ce modèle semi-analytique. / A semi-analytical tool for the design of sandwich structures under intermediate speed loadings impact (<20m.s-1) is proposed by using an efficient solution based on the Fourier series with general boundary conditions. The governing equations, which describe dynamic elastic response of orthotropic laminates and include the non linear Hertzian contact law, are derived by means of explicit time discretization. For the general boundary conditions, the Fourier series solution is supplemented with mixed polynomial-cosine series, which allows derivation of the classical solution by letting the series satisfy exactly the governing differential equation and the boundary conditions with increased values of terms series. To take local physical behavior during sandwich structure impact into account, local plasticity and failure of the protection plate are introduced in a modified form of the Hertzian contact and the compression of the foam is added in the equilibrium equation of the projectile. The solutions obtained with this new method are close to those found by finite element simulations for impact on multilayers composite structures. An experimental campaign with one square meter sandwich structures impacted by corner box projectile is then used to validate the whole model. Finally, the best sandwich structure for energy absorption under a 7kJ impact (material and geometry) is chosen by coupling the model with an optimizer based on the metamodel approach. This solution is applied to a real vehicle and the results confirm the quality of the design of the structure.
8

Aféra Spiegel z roku 1962 a krize kolem České televize na přelomu let 2000/2001 pohledem vybraných konceptů demokratické konsolidace / The Affair "Spiegel" from 1962 and the Czech Television-Crisis from the turn of 2000 and 2001 in Perspective of Selected Concepts of Democratic Consolidation

Benda, Marek January 2016 (has links)
This master thesis deals with the affair Spiegel from 1962 and the Czech Television-Crisis from the turn 2000 and 2001. Both cases are compared by the conceptual approach of democratic consolidation from the Juan Linz's and Alfred Stepan's work The Problems of Democratic Transition and Consolidation (Baltimore, 1996). The analysis aims to find out whether German Federal Republic in 1962 and the Czech Republic on the start of the third millennium fulfilled the first three Linz's and Stepan's criteria of a consolidated democracy. The theoretical chapter highlights some of alternative approaches and discussions about democratic consolidation as an analytical tool in comparative politics.

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