Submitted by Pedro Silva Filho (pfsilva@ipen.br) on 2017-11-17T17:27:31Z No. of bitstreams: 0 / Made available in DSpace on 2017-11-17T17:27:31Z (GMT). No. of bitstreams: 0 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Os elementos de combustível de um reator nuclear de pesquisa tipo MTR (\"Material Testing Reactor\") são, em sua grande maioria, formados por placas de combustível revestidas com alumínio contendo no cerne silicileto de urânio (U3Si2) disperso em matriz de alumínio. Essas placas possuem espessura da ordem de milímetros e comprimentos muito maiores em relação à sua espessura. Elas são dispostas paralelamente no conjunto que forma o elemento combustível, de maneira a formar canais entre elas com poucos milímetros de espessura, por onde escoa o fluido de refrigeração (água leve ou água pesada). Essa configuração, associada à necessidade de um escoamento com altas vazões para garantir o resfriamento das placas em operação, pode gerar problemas de falhas mecânicas das placas de combustível devido às vibrações induzidas pelo escoamento nos canais e, consequentemente, acidentes de proporções graves no caso de velocidade crítica que possa gerar o colapso das placas. Embora não haja ruptura das placas de combustível durante o colapso, as deflexões permanentes excessivas das placas podem causar bloqueio do canal de escoamento no núcleo do reator e levar ao superaquecimento nas placas. Para este trabalho, foram desenvolvidas uma bancada experimental com capacidade para altas vazões volumétricas (Q=100 m3/h) e uma seção de testes que simula um elemento combustível do tipo placa com três canais de resfriamento. A seção de testes foi construída com placas de alumínio e acrílico e foi instrumentada com sensores de deformação, sensores de pressão, um acelerômetro e um tubo de pitot. As dimensões da seção de testes foram baseadas nas dimensões do Elemento Combustível do Reator Multipropósito Brasileiro (RMB), cujo projeto está sendo coordenado pela Comissão Nacional de Energia Nuclear - CNEN. Os experimentos realizados alcançaram o objetivo de chegar à condição de velocidade crítica de Miller com o colapso das placas. A velocidade crítica foi atingida com 14,5 m/s levando a consequente deformação plástica das placas que formam o canal do escoamento. O canal central na entrada da seção de testes apresentou uma abertura de 3 mm em seu centro, causando um grande bloqueio do escoamento nos canais laterais. Este comportamento foi v constatado visualmente durante a desmontagem da seção de testes, ilustrado e discutido na análise de resultados apresentado neste trabalho. O bloqueio dos canais também foi observado por meio de gráficos de queda de pressão e por gráficos das deformações da entrada, centro e saída das placas contra a velocidade média da seção de testes. Observou-se uma queda da resistência hidráulica da seção de testes devido ao aumento da seção transversal de escoamento no canal central e um aumento exponencial das deformações quando da ocorrência da velocidade crítica. Comparativamente, o valor experimental obtido para velocidade crítica na seção de testes foi da ordem de 85% do valor obtido por cálculo com a expressão teórica de Miller. Os experimentos realizados permitiram um melhor entendimento da interação fluido estrutura em elementos de combustível tipo placa como: valores de frequências de vibrações naturais, instabilidade fluido elástica e desenvolvimento de técnicas para a detecção de valores de velocidade crítica. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP / CNPq:481193/2012-0

Nesta dissertação apresentamos uma sequência de atividades não tradicionais, com foco no ensino e na aprendizagem de Geometria, em particular no que se refere às Isometrias no Plano, elaboradas para alunos de Ensino Fundamental, e o resultado de sua aplicação a oito turmas de 9o ano, como forma de desenvolver habilidades de raciocínio desses alunos. Utilizamos para esse experimento o Design Experiment, experimento de ensino fundamentado no aprimoramento contínuo, e a teoria de Van Hiele baseada na tese de doutorado de Adela Jaime-Pastor (1993), com uma série de atividades elaboradas e aplicadas pela professora/pesquisadora envolvendo as translações e as reflexões, através das fases de aprendizagem e níveis de raciocínio que os alunos desenvolvem com a aplicação dessa teoria. Esse experimento foi dividido em dois momentos, aplicação com quatro turmas de 9o ano em 2015 e aplicação com outras quatro turmas de 9o ano em 2016, subdivididos em outras duas situações, atividades sobre translações e atividades sobre reflexões. Os dados desse experimento foram obtidos através das produções dos alunos, que trabalharam em duplas, em sala de aula, registrados por meio de fotos, vídeos e áudios gravados pela própria pesquisadora. Também utilizamos as bonecas de papel de Brigitte Servatius (1997), com as quais foram trabalhadas translações e reflexões. Os alunos participantes do experimento finalizaram-no com noções sólidas das características das isometrias e um visível progresso em seu nível de conhecimento. A forma como as atividades foram realizadas trouxeram reflexos na rotina desses estudantes em sala de aula, tornando evidente que a busca por situações que despertem o interesse dos alunos de forma inovadora pode gerar melhores resultados e a motivação de uma contínua aprendizagem. / In this dissertation we present a sequence of non-traditional activities, focusing on the teaching and learning of Geometry, in particular regarding the Isometrics in the Plan, elaborated for elementary school students, and the result of its application to eight classes of 9th grade , As a way to develop students\' reasoning skills. We used for this experiment the Design Experiment, a teaching experiment based on continuous improvement, and Van Hiele\'s theory based on Adela Jaime-Pastor\'s (1993) doctoral thesis, with a series of activities elaborated and applied by the teacher/researcher involving the translations and the reflections, through the phases of learning and levels of reasoning that the students develop with the application of this theory. This experiment was divided in two moments, application with four classes of 9th grade in 2015 and application with four other groups of 9th grade in 2016, subdivided into two other situations, activities on translations and activities on reflections. The data of this experiment were obtained through the productions of the students, who worked in doubles, in the classroom, recorded through photos, videos and audios recorded by the researcher herself. We also used the paper dolls of Brigitte Servatius (1997), with which we worked on translations and reflections. The students participating in the experiment finalized it with solid notions of the characteristics of the isometries and a visible progress in their level of knowledge. The way the activities were carried out brought reflexes to the routine of these students in the classroom, making it evident that the search for situations that arouse the students\' interest in an innovative way can generate better results and the motivation of continuous learning.

Syftet med denna studie är att undersöka fördröjningsskillnader inom användargränssnitt mellan native­utvecklade appar (utveckling till varje plattform) och appar av typen generated apps. Eftersom arbetet syftar till att bidra med information om prestanda ansågs en experimentell metod vara det bästa valet. Mätning av laddningstider gjordes med hjälp av en videokamera som filmade utförandet av experimenten vilket gjorde metoden simpel och liknar det som en användare kommer att uppleva. Avgränsning till plattformarna Android och iOS gjordes där Xamarin valdes som ramverk inom tekniker som skapar generated apps. Mätdata från experiment som undersökte laddningstider, experiment med användare som hanterade listors respons samt undersökning av CPU­ och minnesanvändning tyder på ett återkommande mönster. Xamarin Forms med XAML är den teknik som presterat sämst under experimenten som sedan följs av Xamarin Forms. Xamarin Android/iOS hade inte lika stora prestandaförluster jämfört med native­utvecklade delar. Generellt hanterar Xamarin Forms telefonens resurser sämre än vad Xamarin Android/iOS och native gör. Resultat från studien kan användas som beslutsstöd vid val av teknik. Studien bidrar även med data som kan användas vid vidare forskning inom området. / The purpose of this study is to examine differences in delay during calculation and presentation of interfaces executing on different techniques. Specifically between native developed apps and generated apps. Since the work aims to contribute with information regarding performance, an experimental method was considered to be the best choice. Measurements of loading times was made with a video camera that captured the execution of the experiments which made the method simple and captures what the users would have experienced. Demarcation to the platforms Android and iOS was made and Xamarin was chosen as the framework for creating generated apps. Data from experiment that examined loading times, experiment with users that dealt with the responsiveness of lists and the analysis of CPU and memory usage indicate a recurring pattern. Xamarin Forms with XAML is the technique that has performed worst during the experiments, followed by Xamarin Forms. Xamarin Android/iOS didn’t have as big performance loss. Xamarin Forms does not manage the phones resources as efficient as Xamarin Android/iOS and native developed apps does. The results from this study can be used as material for making decisions witin organisations when choosing technology for creating apps. The study also contribute with data that can be used by other researchers.

Bönor har visats ha många hälsofrämjande egenskaper, bland annat en fördelaktig fördelning av makronutrienter och vatten, ett lågt kaloriinnehåll, låg fetthalt, långsamma kolhydrater och viktiga mineraler. Samtidigt vill Livsmedelsverket rekommendera en fyrdubbling av intaget av baljväxter hos det svenska folket. Genom att delvis ersätta animaliskt protein med protein från baljväxter menar Livsmedelsverket att intaget av mättat fett och överflödig energi kan minskas, och därmed minskar också risken att drabbas av övervikt och hjärt- och kärlsjukdomar.Syftet med studien är att undersöka vilken attityd en grupp grundskoleelever har till att äta baljväxter, med särskilt fokus på bönor och linser, och att studera hur mycket bönor och linser de äter i dagsläget. Studien vill även pröva ifall eleverna kan få en mer positiv attityd till bönor och linser om de exponeras för olika måltidstillbehör som är baserade på bönor under en tid.Enkäter delades ut före och efter experimentet för att mäta skillnader i attityd mot baljväxter bland skolungdomarna, med frågor om deras attityd till baljväxter samt vegetarisk mat.Resultatet visade en positiv utveckling av attityden till baljväxter. Studiens sammanställda resultat påvisade en förbättrad attityd till baljväxter hos eleverna. Att öka konsumtionen av baljväxter kräver nytänkande kring skapandet av attraktiva rätter eller måltidstillbehör, och arbetet ger flera exempel på hur man kan gå tillväga i framtida försök. / Beans have been proven to habit many healthy qualities, such as a profitable distribution of macro nutrients and water, low contents of calories, low share of fat, presence of slow carbohydrates and important minerals. In addition, Livsmedelsverket (the Swedish National Food Agency) recommends a fourfold increase of the intake of legume for the Swedish population. By partly replacing animal protein with protein from legumes, Livsmedelsverket claim that the intake of saturated fatty acids and superfluous energy may decrease, and thereby reduce the risk to develop obesity or cardiac diseases.The purpose of the study was to examine what attitude a group of elementary school students have towards legumes, with a focus on beans and lentils, and to examine how much beans and lentils they eat in the current situation. The study also want to test if the student can get a more positive attitude towards beans and lentils if they are exposed to different meal accessories based on beans during this period. Envelopes were sent out before and after the experiment, measuring the differences in attitude toward legumes among the students, with questions towards their attitude to legumes and vegetarian food.The results showed an improved attitude towards legumes. The compiled result of the study showed a positive change of attitude amongst the students. Increasing the consumption of legumes requires new ideas in the creating of attractive dishes and side meals, and this study provides several examples of how to continue the work in future projects.

The aim of this thesis is to explore thinking processes of pupils when solving problems of geometric manipulative environment Parquets. I elaborated this environment Parquets and stated characteristic tasks. I have also described, in what mental schemes of mathematical concepts solving tasks may contribute. I made use of pupil's life experiences with the game Ubongo in the presentation of the environment for them. The diploma thesis is presenting the ideas of the constructivist approach to teaching mathematics. Necessary relevant theoretical concepts are defined in the theoretical part. The experiment with third grade, who attended the Math's club is the basis of this diploma thesis. Video recordings were transcribed in the form of a written report and these were analyzed in the aim of diagnosing and describing phenomena that are related to discussions of pupils, their cooperation within the group and the development of mathematical experience, knowledge, skills and abilities of the student, but also the personality and social competences. In the analysis I also pay attention to the role of the experimenter, who was also in the role of a teacher. In conclusion, I made recommendations that could improve the lesson.

Animals affect vegetation in many different ways. In this thesis we have focused on the impact of wild ungulates in the Czech Republic (wild boar, red deer, sika deer, roe deer). These animals affect vegetation with grazing, defoliation, defecation, browsing and other activities. We decided to study the effect of browsing. The animal trails are formed by browsing animals. These trails can be easily recognized due to long-term browsing. They are especially caused by trampling, which affects vegetation in many ways. The aim of this study is to determine how the vegetation of dry-grasslands (Festuco-Brometea) responds to long-term trampling caused by wild ungulates. We found that on trails, there is more bare soil, less litter and lower vegetation. In its close proximity, there is also a slightly greater diversity of plants than in control samples. Species like Plantago media which are growing straight on the trail, have adapted to trampling, while smaller shrubs (eg. Rubus, Crataegus), start to appear 2 meters from the trail. Using Ellenberg values, we found out that heliophile species, which grow on the trails and the species in control samples need more moisture and more nitrogen. Using the experiment with transplanted blocks, we learned how vegetation responds to the introduction/exclusion of...

This diploma thesis deals with chemistry and science after school clubs, which are held in schools or in official public organization called "leisure education centres". Chemistry after school clubs, play an important role in motivating pupils to further study chemistry, enabling them to carry out more experiments, acquiring practical skills, and applying theoretical knowledge. Last but not least, chemistry after school clubs help pupils to spend their leisure time meaningfully. This thesis is divided into the theoretical and practical part. The theoretical part describes the importance of leisure time, motivation for education legal basis for leisure education and other topics related to chemical interest groups. The practical part contains the results and analysis of the questionnaire survey, which was realized mainly among the chemistry teachers. The results of the survey show that the chemistry clubs are mostly focused on the realization of the experiments and the dissemination of the curriculum. And the pupils themselves are primarily interested in establishing of clubs. Most after school clubs aren't organized in leisure education centre. For this reason, they can't use state funding for the clubs, which are organized in leisure education centre.

In this thesis ultrafast exciton dynamics of several colloidal quantum dots have been studied using visible transient absorption spectroscopy. The resultant transient decays and differential transmission spectra were analysed to determine the ultrafast relaxation channels, multiple exciton generation (MEG) efficiency and multi-exciton interactions in the observed materials. All QDs were preliminarily optically characterized using steady state absorption and photoluminescence spectroscopies. In addition, a high repetition infrared femtosecond pump probe experiment was designed and built to detect the picosecond intraband carrier relaxations in quantum dots. Picosecond carrier dynamics of type-II ZnTe/ZnSe and of CuInSe2 and CuInS2 type-I quantum dots were investigated. The common feature of these materials is that they are eco-friendly materials, being alternatives to the toxic Cd- and Pb- based materials. It was found that surface trapping occurred in both cases for electrons in the hot states, and in the minimum of the conduction band for ZnTe/ZnSe core/shell materials. Trion formation was observed in ZnTe/ZnSe core/shell dots at high power and unstirred conditions. The hot and cold electron trapping processes in type-II dots and CuInS2 and CuInSe2 dots shifted, distorted and moderately cancelled the bleach features. In addition, intra-gap hole trapping was observed in CuInS2 and CuInSe2 dots which results in a long decay feature in the recorded transients. MEG competes with Auger cooling, surface mediated relaxation and phonon emission. To enhance the MEG quantum yield, the rival mechanisms were suppressed in well-engineered CdSe/CdTe/CdS and CdTe/CdSe/CdS core/shell/shell and CdTe/CdS core/shell type-II quantum dots. The MEG slope efficiency and threshold for a range of different core size and shell thickness were found to be (142±9)%/Eg and (2.59±0.16)Eg, respectively. The observed threshold was consistent with the literature, whereas, the obtained slope efficiency was about three times higher than the previously reported values. The biexciton interaction energy of the dots stated in the previous paragraph was also studied. To date, time-resolved photoluminescence (TRPL) has been employed to study exciton interactions in type-II quantum dots and large repulsive biexciton interaction energy values between 50-100 meV have been reported. However, unlike the TRPL method, the TA experiment ensures that only two excitons remain in the band edge of the dot. Using this method, large attractive biexciton interaction energies up to ~-60 meV was observed. These results have promising implications regarding enhancing the MEG quantum yield.

Syfte: Syftet med den här studien är att utifrån tidigare forskning ge ett bidrag till förståelsen för hur försäljningspriset påverkas när en köpmäklare finns representerad i en prisförhandling. Metod: Studien är experimentell. Forskningsansatsen utgår från ett deduktivt synsätt med en ontologisk inriktning, och är av explanativ art. Studien är genomförd via ett experiment med 48 stycken simulerade förhandlingar. Givna objekt och givna referenspunkter gavs inför varje enskild förhandling, metodiskt kallade försök. En kontrollgrupp och en experimentgrupp användes för att säkerställa den oberoende variabelns påverkan på den beroende variabeln. Den beroende variabeln likställs med försäljningspriset och den oberoende variabeln med köpmäklarens inverkan. Den procentuella ökningen från utgångspris till försäljningspris i kontrollgruppen ställdes mot den procentuella ökningen från utgångspris till försäljningspris i experimentgruppen för att urskilja köpmäklares representation i prisförhandlingen. Vidare avser forskningsdesignen att korroborera en tidigare studie gjord av Sahin et al. (2013) genom att utveckla och anpassa Sahins et al. (2013) forskningsdesign. En nollhypotes har skapats i avseende att testa den alternativa hypotesen. Resultat och analys: Studiens empiriska resultat anses vara icke signifikant och det kan därmed inte fastställas att en köpmäklares representation i en prisförhandling har en påverkan på försäljningspriset. Således indikerar experimentets genererade värden att enköpmäklare kan ha en viss påverkan på försäljningspriset, men skillnaden mellan kontrollgrupp- och experimentgrupp anses för liten för att resultatet ska kunna anses vara statistiskt signifikant. Detta innebär att en korroborering inte kan anses vara genomförd, utan en falsifiering torde vara ett mer passande begrepp. Vidare kan således inte tidigare forskning stödjas på området. Förslag till vidare forskning: Då den experimentella studien visar en indikation på en representerad köpmäklares påverkan på försäljningspriset torde en studie i större omfattning och skala resultera i en statistiskt signifikant påverkan och därmed förankra ytterligare en forskningsteori. Ett bredare urval i fortsatta studier torde även öka studiens generaliserbarhet. Vidare visar teorigenomgången att en studie av denna art är betydelsefull för forskningsområdet. Uppsatsens bidrag: Arbetets bidrag är att öka förståelsen för köpmäklarens representation i en prisförhandling och dess inverkan på försäljningspriset. Vidare bidrar arbetet med en meta-studie på forskningsområdet och utifrån arbetets empiriska resultat samt tidigare forskning, kan en viss skepsism riktas mot den amerikanska forskningen. Studien ställer en representerad köpmäklare mot avsaknaden av en representerad köpmäklare och fyller därmed det forskningsgap som presenteras. Vidare kan en falsifiering av studien gjord av Sahin et al. (2013) konstateras då det empiriska resultatet inte kan anses vara statiskt signifikant och ett tillägg i debatten om problematiken kring replikering kan således också göras. / Aim: The purpose of this study is, based on previous research, contribute to theunderstanding of how the sales price is affected when a buyer broker is represented in a price negotiation. Method: The study is experimental. The research effort is based on a deductive approach with an ontological orientation and by an explanatory nature. The study was conducted through an experiment with 48 simulated negotiations. Given objects and given reference points were given for each individual negotiation, methodically called attempts. A control group and an experiment group were used to ensurethe independent variable's influence on the dependent variable. The dependent variable is equal to the selling price and the insufficient variable with the effect of the buyer's agent. The percentage increase from the starting price to the selling price of the control group was set against the percentage increase from the starting price to the selling price in the experimental group to distinguish the sales representatives' representation in the price negotiation. Furthermore, the research design relates to corroborating a previous study by Sahin et al. (2013) by developing and adapting Sahins et al. (2013) research design.A zero hypothesis has been created for testing the alternative hypothesis. Result & Conclusion: The empirical results of the study are considered to be non-significant and it can not therefore be established that a buyer broker’s representation in a price negotiation has an effect on the selling price. Thus, the generated values of the experiment indicate that a buyer broker may have a certain effect on the selling price, but the difference between the control group and the experiment group is considered too small to make the result statistically significant. This means that a corroboration can not be considered complete, and a falsification would be a more appropriate term.Furthermore, earlier research can not be supported in this area. Further research: As the experimental study shows an indication of the effect of a representative buyer broker’s effect on the selling price, a study to a greater extent and scale would result in a statistical significance impact and thus anchore a further research theory. A wider selection in further studies would also increase the generalization of the study. Furthermore, the theory review shows that a study of this nature is important for the research area. Contribution of the thesis: The contribution of the work is to increase the understanding of the buyer broker’srepresentation in a price negotiation and its impact on the selling price. Furthermore,thework contributes with a meta-study in the field of research and based on the empirical results of the work and previous research, some skepticism can be directed towards the American research. The study places a buyer broker against the absence of a buyerbroker and thus completes the research gap presented. Furthermore, a falsification of the study made by Sahin et al. (2013) is noted as empirical results can not be considered statistically significant and thus an addition to the debate on the problem of replication can also be done.

The dissertation thesis is focused on the optimization of control parameters of an EDM machine; the subject of optimization is cutting speed and surface topography. The first part of the thesis contains a research study on the technology of electrical discharge machining with the attention paid to the optimization methods use for control parameters of this process. The second part of the thesis is focused on real application of knowledge gained from studied sources. Here, a design of experiment aim at optimizing the parameters of the EDM machine is designed and carried on to maximize the cutting speed with the highest possible surface quallity. The result of the work is to build adequate regression models and find the optimal setting of machine control parameters.