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Singh, Jai, O. N. Srivastava, R. S. Tiwari, and P. Kumar. "Structural and optical investigations of low temperature solution based synthesized ZnO and Ag admix ZnO nanoparticles (NPs)." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20574.
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Rubio-Garcia, Javier. "Strategies to yield water dispersible ZnO NPs synthesized by an organometallic approach." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/891/.
Повний текст джерелаАнотація:
Le nombre d'études sur la synthèse et l'application de matériaux semi-conducteurs a augmente au cours des dernières années dû à la dépendance de propriétés physiques et chimiques de ces matériaux avec la taille. Plusieurs applications ont émergées, notamment dans les domaines de la biomédecine, les cellules solaires ou de l'électronique. Parmi les matériaux semi-conducteurs connus, ZnO nanométrique est un bon candidat pour ces applications car il est relativement peu coûteux et respectueux avec l'environnement. Des méthodes physiques et chimiques permettant la production de nanostructures de ZnO ont été décrites dans la littérature. Certaines applications des nanoparticules de ZnO nécessitent des solutions colloïdales et de ce point de vue, les méthodes chimiques sont avantageuses. Dans notre groupe de recherche, une méthode chimique basée sur la décomposition de précurseurs organométalliques en présence d'un agent de stabilisation a été développée. Cependant, cette stratégie ne permet la production de nanoparticules de ZnO uniquement solubles dans les solvants apolaires. Les applications en cosmétiques ou en biomédecine ne sont alors pas possibles. Le but de cette thèse est la modification de la synthèse organométallique pour atteindre des nanoparticules de ZnO solubles dans l'eau: soit par modification des particules synthétisées ou par modifications de la procédure synthèse initialeThere is an ever increasing interest in the synthesis and application of semiconducting materials due to their size-dependent physical and chemical properties (nanometric range). Multiple applications have radically emerged over the last few years including in the areas of biomedicine, solar cells or electronics. Among the semiconducting materials, nanosized ZnO is a good candidate for these applications as it is a relatively inexpensive and environmentally friendly material. Physical and chemical methods allow for the production of ZnO nanostructures. For some applications ZnO nanoparticles (NPs) are required as colloidal solutions and chemical methods are advantageous. In our research group, a chemical method based on the decomposition of organometallic precursors in the presence of a stabilizing agent has been developed. Good control with respect to the average size and the size distribution is achieved. However, this strategy presents as a main drawback the production of ZnO NPs that are only dispersible in non polar solvents. Application for cosmetics or in the field of biomedicine is impeded as a result. The motivation for this Thesis has been to bring about synthetic modification of the organometallic strategy in order to achieve ZnO NPs dispersible in water: either modification of the as-synthesized particles or changes to the synthetic procedure are mandatory
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Villafuerte, Diaz José Guillermo. "Nanofils de ZnO résistifs synthétisés par dépôt en bain chimique pour capteurs piézoélectriques flexibles." Thesis, Université Grenoble Alpes, 2022. http://www.theses.fr/2022GRALI056.
Повний текст джерелаАнотація:
Les NWs de ZnO hautement résistifs sont destinés à être utilisés comme capteurs de pression dans des substrats flexibles. Pour cela, il était important de développer le rôle important des défauts liés à l'hydrogène et à l'azote dans les NWs de ZnO cultivés par CBD, comme cela a été largement étudié dans cette thèse. Le chapitre 1 détaille l'état de l'art de la présente thèse et le chapitre 2 détaille les procédures expérimentales utilisées pour développer les différentes études de cette thèse. Dans le chapitre 3, la conduction électrique de type métallique des NWs de ZnO cultivés spontanément a été attribuée à une forte densité de porteurs de charge libre due aux défauts liés à l'hydrogène (c'est-à-dire le HBC et le VZn-3H agissant comme des donneurs superficiels). Ensuite, le chapitre 4 démontre la capacité d'ingénierie des NWs de ZnO par recuit thermique sous une atmosphère d'oxygène, montrant que la densité des défauts liés à l'hydrogène diminue à ~300 °C, et que l'activation thermique de VZn-NO-H (agissant comme accepteur profond) à ~450 °C favorise une compensation importante. De plus, l'incorporation intentionnelle d'atomes dopants de Sb dans les NWs de ZnO apporte une nouvelle approche en réalisant les croissances dans les régions à faible et à fort pH, comme cela a été fait dans le chapitre 5. Ainsi, le chapitre 6 élucide la modulation complexe entre les défauts liés à l'hydrogène, à l'azote et à l'antimoine dans les différentes conditions de croissance et de recuit. En particulier, le nouveau recuit en deux étapes à 300 °C pendant 4 heures et une heure consécutive à 450 °C illustre la possibilité de diffuser exogène les donneurs d'hydrogène et d'activer thermiquement les défauts liés au VZn-NO-H et au Sb. Enfin, le chapitre 7 montre l'incorporation de ces NWs de ZnO hautement résistifs comme capteurs piézoélectriques flexiblesHighly resistive ZnO NWs are intended for their application as pressure sensors in flexible substrates. To achieve this, it was important to develop the important role of hydrogen- and nitrogen-related defects in ZnO NWs grown by CBD, as it has been extensively studied in this thesis. Chapter 1 details the state-of-the-art of the present thesis and Chapter 2 details the experimental procedures used to develop the different studies of this thesis. In Chapter 3, the metal-like electrical conduction of spontaneously grown ZnO NWs was attributed to a high density of free charge carriers due to hydrogen-related defects (i.e., HBC and VZn-3H acting as shallow donors). Then, Chapter 4 demonstrates the capacity to engineer the ZnO NWs by thermal annealing under an oxygen atmosphere, showing that the density of hydrogen-related defects would decrease at ~300 °C, and the thermal activation of VZn-NO-H (acting as deep acceptor) at ~450 °C would promote an important compensation. Furthermore, the intentional incorporation of Sb dopant atoms in the ZnO NWs bring a novel approach by performing the growths in the low- and high-pH regions, as performed in Chapter 5. Hence, Chapter 6 elucidates the complex modulation between the hydrogen-, nitrogen- and antimony-related defects at the different growth conditions and the different annealing conditions. Particularly, the novel two-step annealing at 300 °C for 4 h and a consecutive 1 h at 450 °C will illustrate the possibility to exo diffuse the hydrogen-donors and thermally activate the VZn-NO-H and Sb-related defects. Finally, Chapter 7 shows the incorporation of these highly resistive ZnO NWs as flexible piezoelectric sensors
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Magnan, Romain. "Oxyde transparent conducteur de ZnO : V à partir d'une cible de nanoparticules : de l’ablation par laser pulsé à un procédé de décharge à barrière diélectrique double fréquence à pression atmosphérique Transparent and conductive vanadium doped zinc oxide thin films by pulsed laser deposition from different targets Atmospheric pressure dual RF-LF frequency discharge: Influence of LF voltage amplitude on the RF discharge behavior Atmospheric pressure dual RF-LF frequency discharge: transition from α to α-γ-mode". Thesis, Perpignan, 2020. http://www.theses.fr/2020PERP0008.
Повний текст джерелаАнотація:
Cette thèse en cotutelle entre la France et le Canada a pour objectif de développer une méthode innovante d’élaboration de couches minces nano-composites de ZnO:V, basée sur la mise en vol et le dépôt de nanoparticules (NPs) de ZnO :V par des Décharges à Barrière Diélectrique (DBDs) double fréquence. Cette méthode de dépôt vise à réduire le coût de production par l’utilisation de nanoparticules synthétisées par méthode sol-gel et de DBDs dans une configuration permettant le dépôt de couches minces en continu à pression atmosphérique. Les travaux se sont déroulés en trois phases :- L’étude des OTC obtenus par ablation laser à partir d’une cible de NPs de ZnO:V(1 %at.) et de cibles métalliques de ZnV. La résistivité la plus faible (4 x 10 4 Ω.cm) est observée pour les dépôt faits à 250 °C à partir d’une cible de Zn :V(3 %at.) alors que les meilleures propriétés optiques sont celles d’une couche mince quasi-amorphe obtenue à 20 °C à partir de la cible de NPs de ZnO:V. Ces couches minces présentent une transmission de 40% dans l’UV à 250 nm, 90% dans le visible et 80% dans le PIR à 2500 nm) avec une résistivité de 6 x 10-2 Ω.cm. - La recherche et l’optimisation d’une source plasma DBD pour mettre en vol des NPs de ZnO:V dans une configuration compatible avec le dépôt de couches minces contrôlées. La démarche a consisté à chercher à accroître le flux et l’énergie des ions à la cathode en appliquant, sur une des électrodes, une tension radiofréquence (5 MHz) qui génère une forte densité d’ions (~2 x 1011/cm3) et sur l’autre électrode une tension basse fréquence (50 kHz) afin de transporter les ions vers la cathode. La première étape a été de bien comprendre la physique de la DBD RF-BF en couplant la caractérisation optique de la décharge et la modélisation fluide 1D. Lorsque la tension BF augmente, la décharge initialement RF en régime α bascule en régime α-γ durant 1/5 du cycle BF. Les résultats montrent qu’en régime γ la décharge est auto-entretenue dans la gaine et le flux d’ions à la cathode est multiplié par un facteur 7 alors que leur énergie s’accroit d’un facteur 4. L’étude expérimentale montre que lorsqu’une cible de NPs interagit avec une DBD RF-BF, des NPs sont mises en vol.- La conception et le test d’une configuration de réacteur DBD comprenant 2 zones plasmas successives : la première pour mettre en vol les NPs d’une cible, la deuxième pour déposer les NPs sur un substrat. Cette dernière est basée sur une DBD double fréquence BF-BF obtenue par application d’une tension 50 kHz qui génère des électrons pour charger les NPs et une tension 1 kHz dont on sait qu’elle peut assurer le transport des NPs chargées du volume vers les surfaces. La faisabilité a été montrée par l’observation de NPs sur le substratThis thesis jointly supervised by France and Canada aims to develop an innovative method for the development of thin nanocomposite layers of ZnO: V, based on the sputtering and deposition of ZnO: V nanoparticles (NPs) using Double Frequency Dielectric Barrier Discharges (DBDs). This deposition method aims to reduce the cost of production by using nanoparticles synthesized by the sol-gel method and DBD in a configuration allowing the deposition of thin films continuously at atmospheric pressure. The work took place in three phases:- The study of TCO obtained by pulsed laser deposition from a target of NPs of ZnO: V (1% at.) and metal targets of ZnV. The lowest resistivity (4 x 10-4 Ω.cm) is observed for the deposits made at 250 ° C from a Zn: V target (3% at.) While the best optical properties are those of a quasi-amorphous thin layer obtained at 20 ° C from the NPs target of ZnO: V. These thin films have a transmission of 40% in UV at 250 nm, 90% in the visible and 80% in the PIR at 2500 nm) with a resistivity of 6 x 10-2 Ω.cm.- Research and optimization of a DBD plasma source to sputter ZnO: V NPs in a configuration compatible with the deposition of controlled thin films. The approach consisted in increase the flow and energy of the ions at the cathode by applying, on one of the electrodes, a radiofrequency voltage (5 MHz) which generates a high density of ions (~ 2 x 1011 / cm3) and on the other electrode a low frequency voltage (50 kHz) in order to transport the ions to the cathode. The first step was to understand the physics of the DBD RF-BF by coupling the optical characterization of the discharge and the 1D fluid modeling. When the LF voltage increases, the initially RF discharge in the α regime switches to the α-γ regime for 1/5 of the LF cycle. The results show that in γ regime the discharge is self-sustaining in the sheath and the flow of ions at the cathode is multiplied by a factor of 7 while their energy increases by a factor of 4. The experimental study shows that when an NPs target interacts with an RF-BF DBD, NPs are brought into flight.- The design and testing of a DBD reactor configuration comprising 2 successive plasma zones: the first to launch the NPs of a target, the second to deposit the NPs on a substrate. The latter is based on a double frequency BF-LF DBD obtained by applying a 50 kHz voltage which generates electrons to charge the NPs and a 1 kHz voltage which we know can ensure the transport of charged NPs from the volume to surfaces. The feasibility was shown by the observation of NPs on the substrate
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Nascimento, JoÃo Paulo Costa do. "Estudo dos Efeitos da AdiÃÃo de Zn2+ e de Ãons Terras-Raras nas Propriedades DielÃtricas e de LuminescÃncia da Matriz CerÃmica Lanbo4." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13113.
Повний текст джерелаАнотація:
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorCom o rÃpido crescimento de tecnologias sem fio, a indÃstria de telecomunicaÃÃes tem buscado constantemente materiais que possuam excelentes caracterÃsticas dielÃtricas para ser à base de novos dispositivos. Devido a essa demanda sempre crescente, pesquisas em busca de novos e melhores materiais cerÃmicos tÃm ocupado cada vez mais lugar de destaque no interesse da comunidade cientÃfica mundial. O uso de materiais cerÃmicos em busca de materiais fluorescentes tambÃm vem recebendo destaque, jà que materiais desse tipo apresentam diversas aplicaÃÃes, tais como lasers; diodo emissor de luz (LED); como fonte de luz sensores; estocagem de dados Ãticos e atà mesmo na Ãrea mÃdica. Neste trabalho foram estudados as propriedades da matriz cerÃmica LaNbO4 (LNO) modificada pela adiÃÃo de ZnO e tambÃm pela dopagem com Ãons terras-raras Ãrbio; itÃrbio e tÃlio. As amostras de LNO e dopadas foram obtidas atravÃs do mÃtodo reacional do estado sÃlido utilizando Ãxidos precursores seguido de tratamento tÃrmico, enquanto as amostras com ZnO foram obtidas atravÃs da adiÃÃo de determinada quantidade de massa deste sobre o LNO. Os resultados de difraÃÃo de Raios-X e espectroscopia Raman confirmaram a obtenÃÃo da fase cerÃmica LNO e os valores das propriedades dielÃtricas desse material foram prÃximos da literatura. A simulaÃÃo numÃrica realizada para o LNO apresentou bom valor de ganho e alta eficiÃncia, mostrando que esse material pode atuar como DRA. Quanto à adiÃÃo de ZnO, a difraÃÃo de Raios-X mostrou que praticamente nÃo houve mudanÃas no padrÃo de difraÃÃo da fase LNO. Jà com relaÃÃo Ãs propriedades dielÃtricas foi observado que essa adiÃÃo causou aumento nos valores de permissividade e tangente de perda de forma nÃo linear com o aumento da concentraÃÃo de zinco. Nos sistemas contendo Ãons terras-raras a difraÃÃo Raios-X e espectroscopia Raman indicaram que os Ãons dopantes entraram na estrutura cristalina da fase LNO. Na fluorescÃncia foram observadas bandas na regiÃo do verde e vermelho para as amostras com Er3+ e Yb3+, referentes Ãs transiÃÃes dos orbitais 4f do Er3+. Enquanto que para o sistema com Er3+, Yb3+ e Tm3+ foram observadas bandas nas regiÃes do ultra-violeta; azul; verde; vermelho e infravermelho originadas das transiÃÃes dos orbitais 4f do Er3+ e 4f do Tm3+.
With the rapid growth of wireless technologies, the telecommunications industry has constantly searching materials having excellent dielectric characteristics to be based on new devices. Due to this ever increasing demand, research for new and improved ceramic materials have occupied prominent place in the interest of the scientific community worldwide. The use of ceramic materials in search of fluorescent materials also has received attention, since such materials have several applications, such as lasers; light emitting diode (LED); as a source of light sensors; optical data storage and even in the medical field. In this work were studied the properties of LaNbO4 (LNO) matrix modified by adding of ZnO and also by doping with rare-earth ions erbium; ytterbium and thulium. The pure and doped LaNO4 samples were obtained by solid state reaction method using oxide precursor followed by heat treatment, while samples with ZnO was obtained by adding of determined quantity of latter on the LNO. The results of x-ray diffraction and Raman spectroscopy confirmed the formation of the ceramic phase LNO and the values of the dielectric properties obtained of this material were close to the values of the literature. The numerical simulation realized for LNO presented good gain value and a high efficiency, showing that this material can act as a DRA. About the addition of zinc, the x-ray diffraction showed that practically not occured significant changes in the diffraction pattern of LNO phase, being that regarding the dielectric properties was observed that the addition caused increase in the values of the permittivity and loss tangent nonlinearly with the increasing of the concentration of zinc. In the systems containing rare-earth ions the X-ray diffraction and Raman spectroscopy indicated that the dopant ions entered on the crystalline lattice of LNO phase. In the fluorescence were observed bands in the green and red region for the system with Er3+ and Yb3+ , concerning the transitions between the 4f orbitals of Er3+ . While for the system with Er3+ , Yb3+ and Tm3+ were observed bands in the ultraviolet region; blue; green; red and infrared originated of transitions that occur in the 4f orbitals of Er3 + and in the 4f orbitals of Tm3+.
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Gonçalves, Rafael Silva. "Efeitos da interface e da dopagem nas propriedades estruturais, óticas e elétricas de filmes finos de ZnO." Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/5381.
Повний текст джерелаАнотація:
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPqIn this work, we described the structural, morphological, optical and electrical properties of the ZnO thin films undoped and chromium (Cr), copper (Cu), aluminium (Al) doped deposited using magnetron sputtering and co-sputtering method on glasses, Cr and niobium (Nb) substrates. For characterization of the samples were used the X-ray diffraction (XRD), X-ray reflectometry (XRR), UV-Vis spectroscopy in the visible region techniques and IxV plots. This work was divided in two parts, in the study I, ZnO films were grown on glasses substrates and the influence of the substrate temperature, RF power and films thickness at the structural, morphological and optical properties was studied. The results showed that all films grown exhibit characteristic peaks of hexagonal wurtzite phase with axis-c preferential orientation, the films roughness was very influenced by thickness and temperature and the gap energy varied with the films thickness. In the study II, thin films undoped and doped were grown at 300ºC on different substrates and the influence of kind of substrate, dopants, dopant concentration on the structural, morphological, optical and electrical properties was studied. Generally, all samples deposited on Cr substrates exhibit resistance lower than the samples deposited on Nb substrates. For some samples, an unusual behavior was observed at the moment of electrical measurements, after any voltage, different for each sample, the current fell abruptly.
Neste trabalho, descrevemos as propriedades estruturais, morfológicas, ópticas e elétricas de filmes finos de ZnO puros e dopados com cromo (Cr), cobre (Cu) e alumínio (Al) depositados por sputtering e co-sputtering em substratos de vidro, Cr e nióbio (Nb). Foram utilizadas as técnicas de difração de raios X (DRX), reflectometria de raios X (XRR), espectroscopia óptica na região do UV-Vis e curvas de IxV para caracterização das amostras. O trabalho foi dividido em duas etapas, na primeira etapa foram estudados os efeitos da espessura, da temperatura do substrato e da potência RF nas propriedades estruturais, morfológicas e ópticas dos filmes de ZnO crescidos sobre substrato de vidro. Os resultados mostraram que todos os filmes produzidos apresentam picos característicos da fase hexagonal wurtzita com orientação preferencial ao longo do eixo-c, a rugosidade dos filmes foi bastante influenciada pela espessura e temperatura e a energia de gap variou com a espessura dos filmes. Na segunda etapa, filmes finos puros e dopados foram depositados a 300ºC em diferentes substratos. Nesta etapa foram investigados a influência do tipo de substrato e da concentração dos dopantes nas propriedades estruturais, morfológicas, ópticas e elétricas. Os resultados mostraram que a cristalinidade dos filmes de ZnO foi fortemente influenciada pela rugosidade do substrato. De modo geral, todas as amostras depositadas sob substratos de Cr apresentaram resistência menores do que as amostras depositadas sob Nb. Para algumas amostras, um comportamento não usual foi observado no momento das medidas elétricas onde após uma determinada tensão, diferente para cada amostra, a corrente caía abruptamente.
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Silva, Douglas Carlos de Sousa. "Síntese e caracterização de heteroestruturas de Ag2MoO4 e ZnO e investigação da sinergia nas propriedades fotocatalíticas e fotoluminescentes." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7260.
Повний текст джерелаАнотація:
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Nanostructured materials, such as: Ag2MoO4 and ZnO are of great importance because they have unique characteristics and properties, and can be applied in sensors, catalysis, photoluminescence, among other applications. In this work, the Ag2MoO4 and ZnO powders were synthesized separately and in the form of heterostructures, by two different routes, coprecipitation (CP), at room temperature and coprecipitation with subsequent microwave assisted hydrothermal treatment (CPMAHT), at 130 ° C for 30 min, with a heating rate of 10 ° C / min. The heterostructures composed of both materials, Ag2MoO4 and ZnO present in molar proportions ranging from 0.25-2.00%, were synthesized by coprecipitation with subsequent sonochemical processing (CPSP). The Ag2MoO4 samples were obtained with pure cubic phase of spinel type with crystallite size of 143 nm for the sample obtained by CP and 90 nm for the sample obtained by CPTHAM. For the ZnO the hexagonal phase of the wurtzite type, with crystallite sizes of 19 and 49 nm, was obtained for the samples obtained by CP and CPTHAM, respectively. The phases of both Ag2MoO4 and ZnO were observed for the heterostructures obtained by CPSP. The structural and morphological characterization of the obtained materials was performed using X-ray diffraction (XRD) techniques and scanning electron microscopy (SEM). The diffusion reflectance UV-Vis spectroscopy (DRS) was performed to determine the band gap values of the materials. The photoluminescent property was investigated by means of the photoluminescence spectroscopy (PHS) technique, with an improvement in the photoluminescent property of broadband for all the obtained heterostructures. It was also observed that the synergism of the Ag2MoO4 and ZnO materials in the heterostructures resulted in an improvement in the photocatalytic property, leading to a 90% discoloration of the rhodamine B dye in 90 min for the photocatalysis using the Ag2MoO4: 2 ZnO heterostructure.
Materiais nanoestruturados, tais como: o Ag2MoO4 e o ZnO são de grande importância por apresentarem características e propriedades únicas, podendo ser aplicados em sensores, catálise, fotoluminescência, dentre outras aplicações. Neste trabalho, os pós de Ag2MoO4 e ZnO foram sintetizados na sua forma pura por duas rotas diferentes, coprecipitação (CP) a temperatura ambiente e coprecipitação com posterior tratamento hidrotérmico assistido por microondas (CPTHAM), a 130 °C durante 30 min, com taxa de aquecimento de 10 °C/min. Heteroestruturas compostas por ambos os materiais, Ag2MoO4 e ZnO foram obtidas com proporções de 0,25; 0,50; 1 e 2 mols de ZnO para 1 mol de Ag2MoO4. Estas heteroestruturas foram sintetizadas por coprecipitação com posterior processamento sonoquímico (CPPS). As amostras de Ag2MoO4 foram obtidas com fase cúbica pura do tipo espinélio com tamanho de cristalito de 143 nm para a amostra obtida por CP e 90 nm para a amostra obtida por CPTHAM. Para o ZnO foi obtida a fase hexagonal do tipo wurtzita, com tamanhos de cristalito de 19 e 49 nm, para as amostras obtidas por CP e CPTHAM, respectivamente. Foram observadas ambas as fases, tanto do Ag2MoO4 quanto do ZnO para as heteroestruturas obtidas por CPPS. A caracterização estrutural e morfológica dos materiais obtidos foi realizada utilizando das técnicas de difração de raios X (DRX) e microscopia eletrônica de varredura (MEV). A espectroscopia de UV-Vis por reflectância difusa (ERD) foi realizada para determinação dos valores de “band gap” dos materiais. A propriedade fotoluminescente foi investigada por meio da técnica de espectroscopia de fotoluminescência (EFL), sendo observado uma melhora na propriedade fotoluminescente de banda larga para todas as heteroestruturas obtidas. Foi observado também que a sinergia dos materiais Ag2MoO4 e ZnO nas heteroestruturas resultou em uma melhora na propriedade fotocatalítica, levando a uma descoloração do corante rodamina B de 90 % em 90 min para a fotocatálise usando a heteroestrutura Ag2MoO4: 2 ZnO.
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Merissi, Thiago Lima. "A conservação da biodiversidade nos discursos expositivos do Zoo de Barcelona." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/81/81133/tde-24062016-160738/.
Повний текст джерелаАнотація:
A Educação para a Conservação é um campo de pesquisa que se dedica ao estudo das reflexões éticas e das atitudes humanas direcionadas para com o respeito que se deve ter com o ambiente, principalmente pelo estabelecimento de ações conservacionistas pautadas em interações educativas. Os Zoos, de modo geral, estão inseridos nessa perspectiva, uma vez que se apresentam como instituições de cunho educativo voltadas para a conservação da biodiversidade. No entanto, o discurso expositivo apresentado por esses aparatos culturais no Brasil, muitas vezes, não contempla tais elementos em suas exposições. Por este motivo, buscou-se a análise de exposições zoológicas também no exterior, que contemplassem discursos sobre a conservação da biodiversidade em suas exposições, tendo sido escolhida a exposição do Zoo de Barcelona, Espanha, para a realização desta investigação. A pesquisa teve por objetivos compreender como a conservação da biodiversidade é abordada na exposição deste zoológico catalão, com base na formulação de saberes de referência constituídos a partir de diferentes áreas: os Movimentos Ambientalistas, a Filosofia da Conservação e as Éticas Ambientais. Igualmente, buscou-se compreender como o discurso expositivo sobre conservação encontra-se apresentado nos aparatos expográficos distribuídos ao longo da exposição, bem como em livros e documentos. Compreendendo a investigação como um Estudo de Caso, foram acessados documentos institucionais de acesso público encontrados no site da instituição e textos presentes nos painéis expositivos. As análises foram realizadas com base no referencial teórico da Transposição Didática/Museográfica, que permite o estudo da exposição por ao menos três lógicas: a lógica do discurso; a lógica do espaço; e a lógica do gesto. Além disso, o mesmo referencial prevê o estabelecimento de um saber de referência ou saber sábio pautado no conhecimento epistemológico sobre a conservação da biodiversidade e, nesta pesquisa, no discurso de pesquisadores da área, que foram entrevistados sobre este assunto. Este saber de referência ou saber sábio possibilitou a criação de um conjunto de categorias de análise que pautou a análise do discurso expositivo apresentado pelo Zoo de Barcelona. As categorias criadas foram classificadas em duas dimensões: a dos Valores e a das Ações. Duas categorias, a Antropocêntrica e a Não antropocêntrica constituíram a Dimensão dos Valores e quatro categorias, a Desenvolvimentista, a Sustentabilista, a Sócio-humanística e a Técnico-científica constituíram a Dimensão das Ações. Os resultados apontaram que o discurso expositivo é composto predominantemente por informações Técnico-científicas e Sustentabilistas, ambas as categorias contextualizadas por uma visão não antropocêntrica de valorização da natureza. A forma como o discurso expositivo encontra-se apresentado na parte textual da exposição corrobora a linha conceitual de assuntos abordados nos grandes eventos globais promovidos pela ONU ao longo dos últimos 40 anos, sobre a conservação do meio ambiente. Categorias como a Sócio-humanística, a Antropocêntrica e a Dimensão dos Valores foram pouco abordadas. A categoria Desenvolvimentista não foi encontrada na exposição. Pelas evidências levantadas durante a análise dos dados pode-se concluir que o Zoo de Barcelona apresenta um discurso expositivo conservacionista e que há elementos suficientes na exposição para se apontar o desenvolvimento de uma Educação para a Conservação.Education for Conservation is a research field dedicated to the study of ethical reflections and human attitudes directed towards the respect which must have it for the environment, especially the establishment of conservation actions based on educational interactions. Zoos, in general, are entered in this perspective, as it is presented as an educational institutions type directed to the conservation of biodiversity. Though, the expositive speech presented by this cultural mechanism in Brazil often does not include this kind of elements in its exhibitions. Therefore, it sought the zoo expositions analysis also abroad, that addressed discourses on biodiversity conservation in their expositions, which was chosen the Zoo of Barcelona\' exposition, Spain, to perform this research. The research aimed to understand how biodiversity conservation is addressed in this exposition Catalan zoo, based on the formulation made up from different areas of knowledge reference: the Environmental Movement, the Conservation Philosophy and Environmental Ethics. Also, it sought to understand how the expositive speech on conservation is presented in expographic devices distributed throughout the exhibition, as well as books and documents. Understanding the investigation as a Study\'s Case, it was accessed institutional documents of publicly accessible found on other website and present texts in the exhibition panels. The analysis were performed based on the theoretic framework of Didactic Transposition/ Museographic, allowing the expositive study for at least three logics: the logic of speech; the logic of the space; and the management logic. Moreover, the same reference provides for the establishment of a knowledge reference or wise knowledge, guided the epistemological knowledge about the conservation of biodiversity and, in this study, the area\'s researchers, who were interviewed on this subject. This reference knowledge or wise knowledge allowed creating a set of categories of analysis that guided the analysis of expositive speech presented by the Zoo of Barcelona. The created categories were classified in two dimensions: Values and Actions. Two categories, Anthropocentric and non-anthropocentric composed the Values Dimension and four categories, Developmental, the Sustainable, the Socio-humanistic and technical-scientific formed the Actions Dimension. The results showed that the expositive speech consists mainly of Technical- scientific and Sustainable information, both contextualized categories by a non-anthropocentric vision of nature appreciation. The way the expositive discourse is presented in the textual part of the exhibition confirms the conceptual range of issues addressed in major global events organized by the ONU over the past 40 years on the conservation of the environment. Categories such as socio-humanistic, the Anthropocentric and Dimension Values were rarely addressed. The Developmental category was not found in the exposition. The evidence gathered during the data analysis can be concluded that the Zoo of Barcelona presents a conservation exhibition speech and that there are sufficient elements in the exhibition to point out the development of an Education for Conservation.
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Gomes, Mônica Borges. "Efeito magnetocalórico nos compostos Gd(Zn1-xCdx) e Gd(Pd1-xRhx)." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=684.
Повний текст джерелаАнотація:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorNesta dissertação, calculamos as propriedades magnéticas e termodinâmicas e o efeito magnetocalórico em compostos do tipo Gd(A1-xBBx), onde A e B são elementos não magnéticos. Para tal finalidade, usamos um modelo hamiltoniano de spins localizados, incluindo o acoplamento com um campo magnético externo. A interação spin-spin é tratada na aproximação de campo molecular. O parâmetro de interação de troca indireta entre os spins localizados é calculado como uma função da concentração de impurezas. Para esse fim, usamos um modelo no qual a desordem química é tratada na aproximação do potencial coerente. Aplicamos o modelo para estudar o efeito magnetocalórico nos compostos Gd(Zn1-x Cdx) e Gd (Pd1-xRHx). As variações adiabáticas da temperatura e as variações isotérmicas da entropia calculadas para variações de campo magnético estão em bom acordo com os dados experimentais.
In this work we calculated the magnetic and thermodynamic properties as well as the magnetocaloric effect in the compounds Gd(A1−xBBx), where A and B are non-magnetic impurities. For this purpose, we use a model Hamiltonian of interacting spin including the coupling with an external magnetic field. The spin-spin interaction is treated in the molecular field approximation. The indirect exchange interaction parameter between localized spins is calculated as a function of the impurity concentration. To this end we use a model in which the disorder is treated in the coherent potential approximation. We apply the model to study the magnetocaloric effect in the compounds Gd(Zn1−xCdx) and Gd(Pd1−xRhx). The calculated adiabatic temperature changes and isothermal entropy changes upon magnetic field variations are in good agreement with the available experimental data.
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Silva, Paulo Maria de Oliveira e. "Estudo dos efeitos da adiÃÃo de ZnO e Nb2O5 nas propriedades dielÃtricas da matriz cerÃmicas BaBi4Ti4O15 (BBT) e suas aplicaÃÃes em antenas." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10945.
Повний текст джерелаАнотація:
nÃo hÃCom o rÃpido crescimento das indÃstrias de telecomunicaÃÃes criou-se uma forte necessidade por materiais cerÃmicos para aplicaÃÃes em micro-ondas. Devendo estes materiais apresentar alta permissividade dielÃtrica (εr), elevado fator de qualidade (Q), boa estabilidade tÃrmica (τf Â10 ppm/ÂC) e baixo custo. Com a invenÃÃo de telefones celulares portÃteis, o campo da comunicaÃÃo sem fio passou por um crescimento inovador nas Ãltimas dÃcadas. O sucesso da terceira geraÃÃo (3G) dos serviÃos de comunicaÃÃo de telefonia celular, motiva o desenvolvimento de banda larga de quarta geraÃÃo (4G) de telefones celulares e outros produtos e serviÃos sem fio, como por exemplo, o Bluetooth. Este trabalho consiste no desenvolvimento e caracterizaÃÃo da cerÃmica de titanato de bÃrio-bismuto (BaBi4Ti4O15) com adiÃÃo de Ãxido de niÃbio (Nb2O5) ou Ãxido de zinco (ZnO), visando a diminuiÃÃo da temperatura de sinterizaÃÃo e possivelmente melhorar a densificaÃÃo, e posteriormente, verificar as modificaÃÃes ocorridas nas propriedades do material, como por exemplo, o coeficiente de temperatura da frequÃncia ressonante (τf). As sÃries cerÃmicas foram produzidas usando a reaÃÃo no estado sÃlido, com o uso de moagem mecÃnica de alta energia e tratamento tÃrmico. A caracterizaÃÃo estrutural foi realizada com base na Microscopia EletrÃnica de Varredura (MEV) e Picnometria. As densidades relativas das amostras adicionadas com (ZnO) a de maior concentraÃÃo teve valor de 77% enquanto que o BBT puro o valor foi de 56%. As densidades relativas das amostras adicionadas com (Nb2O5) a de maior concentraÃÃo teve valor de 61% em relaÃÃo ao BBT puro. Foram realizados experimentos para avaliaÃÃo do comportamento elÃtrico e dielÃtrico das amostras, na faixa de Micro-ondas e RadiofrequÃncia (temperatura ambiente e com variaÃÃo de temperatura). Por fim, o material foi testado como uma DRA, e posteriormente os resultados obtidos foram simulados atravÃs do programa HFSS. As caracterÃsticas da DRA da cerÃmica pura sÃo 1,12dBi de ganho e 32,51% de eficiÃncia. A DRA que foi adicionada com 2% de (ZnO) apresentou ganho de 1,16dBi com 33,96% de eficiÃncia, enquanto a que foi adicionada com 5% de (Nb2O5) apresentou 1,41dBi de ganho com 42,21% de eficiÃncia.
With the rapid growth of the telecommunications industry created a strong need for ceramic materials for applications in microwave. These materials should exhibit high dielectric permittivity (εr), high quality factor (Q), good thermal stability (τf Â10 ppm/ÂC) and low cost. With the invention of mobile phones, the field of wireless communication has undergone a revolutionary growth in recent decades. The success of the third generation (3G) services in mobile communication, motivates the development of broadband fourth generation (4G) of mobile phones and other wireless products and services, such as Bluetooth. Nowadays it is well known the use of tablets, which are increasingly gaining market and encouraging the development of new technologies to improve the flow of information. This work involves the development and characterization of the barium bismuth titanate ceramic, (BaBi4Ti4O15) with addition of niobium oxide (Nb2O5) or zinc oxide (ZnO) in order to decrease the sintering temperature and possibly improve the densification and subsequently check the modifications on material properties, such as the temperature coefficient of resonant frequency (τf). The series ceramics were produced using the solid state reaction with the use of high energy mechanical milling and heat treatment. The structural characterization was performed based on Scanning Electron Microscopy (SEM) and Measurement by Pycnometer. The relative densities of the samples with added (ZnO) had the highest concentration value of 77% pure BBT while the value was 56%. The relative densities of the samples spiked with (Nb2O5) had the highest concentration value of 61% compared to pure BBT. Experiments were conducted to evaluate the electrical and dielectric behavior of the samples in the range of Microwave and Radio Frequency (temperature and temperature variation). Finally, the material was tested as a DRA, and then the results were simulated using the HFSS program. The characteristics of the pure ceramic DRA are 1,12dBi gain and 32,51% efficiency. The DRA added with 2% (ZnO ) showed 1.16dBi gain with 33,96% efficiency , while the one that was added with 5% (Nb2O5) showed gain of 1.41dBi with 42,21% efficiency.
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Silva, Paulo Maria de Oliveira. "Estudo dos efeitos da adição de ZnO e Nb2O5 nas propriedades dielétricas da matriz cerâmica BaBi4Ti4O15 (BBT) e suas aplicações em antenas." reponame:Repositório Institucional da UFC, 2013. http://www.repositorio.ufc.br/handle/riufc/7884.
Повний текст джерелаАнотація:
SILVA, P. M. O. Estudo dos efeitos da adição de ZnO e Nb2O5 nas propriedades dielétricas da matriz cerâmica BaBi4Ti4O15 (BBT) e suas aplicações em antenas. 2013. 148 f. Tese (Doutorado em Engenharia de Teleinformática) - Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2013.Submitted by Marlene Sousa (mmarlene@ufc.br) on 2014-04-02T12:23:02Z No. of bitstreams: 1 2013_tese_pmosilva.pdf: 5352918 bytes, checksum: c95bbc0a17fa84806fa1decf60d2346c (MD5)
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With the rapid growth of the telecommunications industry created a strong need for ceramic materials for applications in microwave. These materials should exhibit high dielectric permittivity (εr), high quality factor (Q), good thermal stability (τf ±10 ppm/ºC) and low cost. With the invention of mobile phones, the field of wireless communication has undergone a revolutionary growth in recent decades. The success of the third generation (3G) services in mobile communication, motivates the development of broadband fourth generation (4G) of mobile phones and other wireless products and services, such as Bluetooth. Nowadays it is well known the use of tablets, which are increasingly gaining market and encouraging the development of new technologies to improve the flow of information. This work involves the development and characterization of the barium bismuth titanate ceramic, (BaBi4Ti4O15) with addition of niobium oxide (Nb2O5) or zinc oxide (ZnO) in order to decrease the sintering temperature and possibly improve the densification and subsequently check the modifications on material properties, such as the temperature coefficient of resonant frequency (τf). The series ceramics were produced using the solid state reaction with the use of high energy mechanical milling and heat treatment. The structural characterization was performed based on Scanning Electron Microscopy (SEM) and Measurement by Pycnometer. The relative densities of the samples with added (ZnO) had the highest concentration value of 77% pure BBT while the value was 56%. The relative densities of the samples spiked with (Nb2O5) had the highest concentration value of 61% compared to pure BBT. Experiments were conducted to evaluate the electrical and dielectric behavior of the samples in the range of Microwave and Radio Frequency (temperature and temperature variation). Finally, the material was tested as a DRA, and then the results were simulated using the HFSS program. The characteristics of the pure ceramic DRA are 1,12dBi gain and 32,51% efficiency. The DRA added with 2% (ZnO ) showed 1.16dBi gain with 33,96% efficiency , while the one that was added with 5% (Nb2O5) showed gain of 1.41dBi with 42,21% efficiency.
Com o rápido crescimento das indústrias de telecomunicações criou-se uma forte necessidade por materiais cerâmicos para aplicações em micro-ondas. Devendo estes materiais apresentar alta permissividade dielétrica (εr), elevado fator de qualidade (Q), boa estabilidade térmica (τf ±10 ppm/ºC) e baixo custo. Com a invenção de telefones celulares portáteis, o campo da comunicação sem fio passou por um crescimento inovador nas últimas décadas. O sucesso da terceira geração (3G) dos serviços de comunicação de telefonia celular, motiva o desenvolvimento de banda larga de quarta geração (4G) de telefones celulares e outros produtos e serviços sem fio, como por exemplo, o Bluetooth. Este trabalho consiste no desenvolvimento e caracterização da cerâmica de titanato de bário-bismuto (BaBi4Ti4O15) com adição de óxido de nióbio (Nb2O5) ou óxido de zinco (ZnO), visando a diminuição da temperatura de sinterização e possivelmente melhorar a densificação, e posteriormente, verificar as modificações ocorridas nas propriedades do material, como por exemplo, o coeficiente de temperatura da frequência ressonante (τf). As séries cerâmicas foram produzidas usando a reação no estado sólido, com o uso de moagem mecânica de alta energia e tratamento térmico. A caracterização estrutural foi realizada com base na Microscopia Eletrônica de Varredura (MEV) e Picnometria. As densidades relativas das amostras adicionadas com (ZnO) a de maior concentração teve valor de 77% enquanto que o BBT puro o valor foi de 56%. As densidades relativas das amostras adicionadas com (Nb2O5) a de maior concentração teve valor de 61% em relação ao BBT puro. Foram realizados experimentos para avaliação do comportamento elétrico e dielétrico das amostras, na faixa de Micro-ondas e Radiofrequência (temperatura ambiente e com variação de temperatura). Por fim, o material foi testado como uma DRA, e posteriormente os resultados obtidos foram simulados através do programa HFSS. As características da DRA da cerâmica pura são 1,12dBi de ganho e 32,51% de eficiência. A DRA que foi adicionada com 2% de (ZnO) apresentou ganho de 1,16dBi com 33,96% de eficiência, enquanto a que foi adicionada com 5% de (Nb2O5) apresentou 1,41dBi de ganho com 42,21% de eficiência.
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Silva, Ana Paula Bispo da. "Fabricação caracterização dos sistemas vítreos TeO2-ZnO-Na2O e TeO2-Nb2O5-Bi2O3 para dispositivos ópticos nas janelas de 1.3 [micrômetro] e 1.5 [micrômetro]." [s.n.], 1998. http://repositorio.unicamp.br/jspui/handle/REPOSIP/278247.
Повний текст джерелаАнотація:
Orientador: Luiz Carlos BarbosaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
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Resumo: Nesta dissertação apresentamos a síntese dos sistemas vítreos TeO2-ZnO-Na2O e TeO2-Nb2O5-Bi2O3 , visando obter dispositivos ópticos nas janelas de 1.3 e 1.5 mm.As amostras foram dopadas com Érbio, Praseodímio e Itérbio, que emitem nos comprimentos de onda de interesse. Os sistemas foram caracterizados estruturalmente utilizando-se técnicas de difração de raios-x' densimetria e Espectroscopía Raman. A caracterização óptica das amostras foi feita por índice de refração linear, fotoluminescência, tempo de vida de decaimento e Espectroscopía UV-Vis-IV. As propriedades térmicas foram caracterizadas por dilatometria, análise térmica diferencial e viscosidade. Estes sistemas apresentaram alta estabilidade térmica, com a diferença entre as temperaturas de transição vítrea e cristalização em tomo de 100 oC. Na viscosidade de puxamento de fibra, em 105.5 e 106 poise, os sistemas não apresentaram picos de cristalização, o que nos permitiu fazer o puxamento das fibras dopadas com terras raras com sucesso. O alto valor de índice de refração apresentado, 2.2, indica um material óptico não linear importante para aplicações em dispositivos ópticos de chaveamento. Os espectros de fotoluminescência mostraram uma largura de banda de 100 nm, muito mais larga que as de sílica dopada com Er, que têm 30 nm. A alta solubilidade das terras raras nos sistemas vítreos permitiu-nos dopá-los com até 70000 ppm, duas ordens maior do que a suportada pelas fibras comerciais existentes, que têm sua luminescência prejudicada pelo efeito de relaxação cruzada. O tempo de vida de decaimento ficou entre 2 e 4 ms, mostrando que nos sistemas estudados o efeito de relaxação cruzada é bem menor que na sílica. Os resultados mostraram a possibilidade de se fabricar amplificadores ópticos integrados de pequenas dimensões com altas concentrações de terras raras e 3 vezes mais canais que os amplificadores existentes
Abstract: In this thesis we presented the synthesis of the vitreous systems, TeO2-ZnO-Na20 and TeO2-Nb2O5-Bi2O3 , in our search for materials to be used in optical devices in the communication windows of 1.3 and 1.5 mm. The samples were doped with Erbium, Praseodymium and Ytterbiurn, which show light emission in the wanted wavelength windows. These systems were structurally and physically characterized by X-ray diffraction techniques, Raman and density measurements. The optical characterizations of the bulk samples were made by linear refraction index, photoluminescence and photoluminescence decay lifetime measurements and UV-VIS-IR absorption Spectroscopy. The thermal properties were characterized by dilatometry and viscosity measurements. These systems presented a high thermal stability, with a 100° C temperature difference between the crystallization and the softening point temperatures. The viscosity was in the range 105.5 to 106 poise between these temperatures indicating the possibility to draw optical fibers, therefore we developed a capillar suction method to make the nucleous of a core-cladding optical fibers, which allowed us to successfully draw rare earth doped optical fibers. The very high linear refraction index, 2.2, indicates a highly non linear optical material, important for ultrafast optical devices applications. The photoluminescence spectra show light emission in a 100 nm wavelength bandwidth, much larger than the 30 nm usually obtained with Er doped silica fibers. Because of the high rare earth solubility in these systems we have been able to dope our glass up to 70,000 ppm, two orders of magnitude above the usual commercial doped fibers doping levels, which are limited by the luminescence quenching due to cross relaxation effects. The photoluminescence decay lifetime in the range of 2 to 4 ms show that the cross-relaxation effects in these rare earth glass hosts is much smaller than in silica. These results show the possibility to manufacture small, integrated optical amplifiers with very high rare earth concentration with 3 times more wavelength channels than the commercially used amplifiers
Mestrado
Física
Mestre em Física
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Silva, Ana Paula Santos da. "Análise da influência da adição de nanopartículas de ZnO nas propriedades físico-mecânicas e de transferência de calor em painéis de fibras de madeira /." Guaratinguetá, 2018. http://hdl.handle.net/11449/153525.
Повний текст джерелаАнотація:
Orientador: Cristiane Inácio de CamposBanca: Julio Cesar Molina
Banca: André Luis Christoforo
Resumo: O segmento de painéis à base de madeira tem se destacado no setor madeireiro pelo uso de tecnologia moderna em seus equipamentos e uso mais racional da matéria-prima. No entanto, a busca por produtos melhores e mais competitivos é constante tendo em vista o mercado ser bastante exigente. Sendo assim, definiu-se como objetivo deste estudo a adição de nanopartículas de óxido de zinco (ZnO) na fabricação de painéis de fibras de média densidade e avaliar as influências das mesmas nas propriedades físicas e mecânicas dos painéis produzidos com dois adesivos comerciais e ainda verificar a influência das nanopartículas na transferência de calor durante o processo de prensagem. Os painéis foram produzidos com adição de 0,5% e 1% de nanopartículas com base no peso seco de fibras e painéis testemunha com resina ureia-formaldeído (UF) e melamina-formaldeído (MF) e, os mesmos caracterizados a partir da ABNT NBR 15.316-2:2015. Durante o processo de prensagem através de sistema de aquisição de dados acoplado a um termopar foram obtidas as variações de temperatura do colchão ao longo dos dez minutos do ciclo de prensagem. A partir dos resultados pode-se concluir que o uso das nanopartículas na proporção de 0,5% de nanopartículas não indicou grandes interferências nas propriedades físico-mecânicas dos painéis estudados. A adição de 1% de nanopartículas tanto nos tratamentos com MF e UF interferiu de forma negativa na interação com o adesivo e, assim, reduziu as propriedades físicas e mecânic... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The wood-based panels stood out in the wood segment by the use of modern technology in their equipment and more rational use of the raw material. However, the demand for better and more competitive products is constant, given that the market is quite demanding. Thus, the aim of this study was to add zinc oxide (ZnO) nanoparticles in the production of medium density fiberboards and to evaluate their influence on the physical and mechanical properties of the panels produced with two commercial adhesives and to verify the influence of nanoparticles on the heat transfer during the pressing process. The panels were produced with 0.5% and 1% of nanoparticles based on the dry weight of fibers and control panels with ureaformaldehyde (UF) and melamine-formaldehyde resin (MF) and characterized by ABNT NBR 15.316-2:2015. During the pressing process through a data acquisition system coupled to a thermocouple, the temperature variations of the mattress were obtained during the ten minutes of the pressing cycle. From a preliminary analysis of the results it can be concluded that the use of nanoparticles in the proportion of 0.5% of nanoparticles did not indicate large interferences in the physical-mechanical properties of the panels studied. The addition of 1% of nanoparticles in both MF and UF treatments interfered negatively in the interaction with the adhesive and thus reduced the physical and mechanical properties of the panels and assisted the heat transfer from the second pressing cycle
Mestre
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Silva, Ana Paula Santos da [UNESP]. "Análise da influência da adição de nanopartículas de ZnO nas propriedades físico-mecânicas e de transferência de calor em painéis de fibras de madeira." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153525.
Повний текст джерелаАнотація:
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O segmento de painéis à base de madeira tem se destacado no setor madeireiro pelo uso de tecnologia moderna em seus equipamentos e uso mais racional da matéria-prima. No entanto, a busca por produtos melhores e mais competitivos é constante tendo em vista o mercado ser bastante exigente. Sendo assim, definiu-se como objetivo deste estudo a adição de nanopartículas de óxido de zinco (ZnO) na fabricação de painéis de fibras de média densidade e avaliar as influências das mesmas nas propriedades físicas e mecânicas dos painéis produzidos com dois adesivos comerciais e ainda verificar a influência das nanopartículas na transferência de calor durante o processo de prensagem. Os painéis foram produzidos com adição de 0,5% e 1% de nanopartículas com base no peso seco de fibras e painéis testemunha com resina ureia-formaldeído (UF) e melamina-formaldeído (MF) e, os mesmos caracterizados a partir da ABNT NBR 15.316-2:2015. Durante o processo de prensagem através de sistema de aquisição de dados acoplado a um termopar foram obtidas as variações de temperatura do colchão ao longo dos dez minutos do ciclo de prensagem. A partir dos resultados pode-se concluir que o uso das nanopartículas na proporção de 0,5% de nanopartículas não indicou grandes interferências nas propriedades físico-mecânicas dos painéis estudados. A adição de 1% de nanopartículas tanto nos tratamentos com MF e UF interferiu de forma negativa na interação com o adesivo e, assim, reduziu as propriedades físicas e mecânicas dos painéis e, auxiliou a transferência de calor a partir do segundo ciclo de prensagem.
The wood-based panels stood out in the wood segment by the use of modern technology in their equipment and more rational use of the raw material. However, the demand for better and more competitive products is constant, given that the market is quite demanding. Thus, the aim of this study was to add zinc oxide (ZnO) nanoparticles in the production of medium density fiberboards and to evaluate their influence on the physical and mechanical properties of the panels produced with two commercial adhesives and to verify the influence of nanoparticles on the heat transfer during the pressing process. The panels were produced with 0.5% and 1% of nanoparticles based on the dry weight of fibers and control panels with ureaformaldehyde (UF) and melamine-formaldehyde resin (MF) and characterized by ABNT NBR 15.316-2:2015. During the pressing process through a data acquisition system coupled to a thermocouple, the temperature variations of the mattress were obtained during the ten minutes of the pressing cycle. From a preliminary analysis of the results it can be concluded that the use of nanoparticles in the proportion of 0.5% of nanoparticles did not indicate large interferences in the physical-mechanical properties of the panels studied. The addition of 1% of nanoparticles in both MF and UF treatments interfered negatively in the interaction with the adhesive and thus reduced the physical and mechanical properties of the panels and assisted the heat transfer from the second pressing cycle
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Berger, Danielle [UNESP]. "Efeito da pressão na obtenção e nas propriedades óticas e sensoras de filmes finos à base de 'SN''O IND. 2' com a adição de 'ZNO'." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/108496.
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000747644.pdf: 3893310 bytes, checksum: ecfe700891aaef7aad573147e7f29c92 (MD5)Neste trabalho foram obtidos filmes finos de SnO2 com adição de ZnO (1% mol; 1,5% mol; 2% mol) depositados por spin coating. Foi realizado estudo pela diferença do tratamento térmico a 330°C por 32h após obtenção de fase cristalina a 550°C por 2h. O tratamento térmico dos filmes finos a 330°C por 32h em forno convencional e em forno sob pressão de 2MPa em ar foi comparado quanto a suas propriedades óticas e sensoras. Para filmes finos tratados termicamente a 330°c por 32h observou-se que a adição de ZnO tem influência no tamanho de grão de 8nm (± 3 nm) para 6nm (± 3 nm). Entretanto para os filmes finos sob pressão de 2 MPa em ar há um aumento do tamanho de grão. Nos filmes finos de SnO2 e ZnO o tratamento térmico a 330°c por 32hsob pressão de 2 MPa em ar tem grande influência no tamanho de grão e na espessura. Obteve-se fase cristalina tetragonal cassiterita para SnO2 e fase cristalina hexagonal wurtzita zincita para ZnO. Nos filmes finos de SnO2 + 1,5% em mol de ZnO e SnO2 + 2% em mol de ZnO o tratamento térmico a 330°C por 32h sob pressão de 2 MPa em ar aparece uma fase secundária de Zn2SnO4 como consequência de menor solubilidade de ZnO em SnO2. As propriedades óticas de fotoluminescência indicaram que o tratamento térmico a 330°C por 32h sob pressão de 2 MPa em ar leva a um deslocamento para a região em menores comprimento de onda (violeta) onde predominam defeitos rasos como vacâncias de oxigênio. Para os filmes finos com adição de ZnO há uma tendência ao aumento do Egap e maior ordenamento da estrutura. Nas propriedades sensoras obteve-se melhor resposta do gás hidrogênio (H2) para o filme fino de ZnO tratado termicamente a 330°c por 32h sob pressão de 2 MPa em ar onde há aumento de área superficial específica para reações de adsorção e dessorção do gás H2.
In this work thin films of SnO2 with addition of ZnO using 1% mol, 1,5% mol and 2% mol deposited in Si substrate by spin coating were obtained. A study by different thermal treatment at 330°c for 32h was realized after obtaining crystalline phase at 550°C for 2h. The thermal treatment in thin films at 330°c for 32h in a furnace conventional and in a furnace under pressure of 2MPa was compared to the optical and sensor properties. For the thin films thermically treated at 330°c for 32h in normal conditions of the atmospheric pressure it was observed that when we add ZnO in SnO2 the grain size decrease from 8nm (± 3 nm) para 6nm (± 3 nm). However for the thin films thermically treated under pressure of 2MPa in air there was an increase in the grain size. In the thin films of SnO2 and ZnO the thermal treatment at 330°c for 32h under pressure of 2 MPa in air has a great influence in the thickness and the grain size. The thin films crystallize in tetragonal phase cassiterite to SnO2 and crystallize in hexagonal wurtzite phase zincite to ZnO. In the thin films SnO2 + 1% mol ZnO, SnO2 + 1,5% mol ZnO and SnO2 + 2% mol ZnO the thermal treatment at 330°C for 32h under pressure of 2MPa in air the second phase of the Zn2SnO4 appears as a consequence of a minor solubility of ZnO in the SnO2. The optical properties of photoluminescence show the thermal treatment at 330°c for 32h under pressure of 2MPa in air leads to a violet shift where shallow defects are predominantly in this region like oxygen vacancies. For the thin films with ZnO addicted there is a tendency to increase the Egap and major structure ordering. In the sensor properties was obtained a better response to hydrogen gas (H2) for the ZnO thin films thermically treated at 330°c for 32h under pressure of 2 MPa in air there is an increase the specific surface area to adsorption and desorption reaction with H2 gas.
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Leite, Camila Marcon de Carvalho. "Zinco para arroz e soja: doses, aproveitamento pelas culturas, fitodisponibilidade e formas desse elemento no solo." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-20062016-111348/.
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A deficiência de Zn no solo causa efeitos indesejáveis na produção agrícola, pois a baixa disponibilidade deste micronutriente para as plantas promove a diminuição da atividade enzimática, além da deficiência deste elemento na alimentação, que pode levar ao estado de subnutrição. Tendo em vista a problemática do Zn no sistema solo-planta e suas variações nos compartimentos do solo, é importante a avaliação de sua fitodisponibilidade e as frações do solo que este elemento está associado. O objetivo deste trabalho foi avaliar a fitodisponibilidade e a compartimentalização de Zn no solo, para as culturas de arroz (Oryza sativa L.) e soja (Glycine max L. Merrill) e avaliar o efeito das doses de Zn sobre a nutrição e exportação deste nutriente pela cultura. Utilizou-se como plantas teste as culturas de arroz e soja para avaliar o efeito das doses de Zn sobre a nutrição e translocação deste nutriente até os grãos. Para tanto, uma amostra de um Latossolo Vermelho, textura argilosa da região de Piracicaba (SP) foi utilizada e ZnCl2 (marcado com 65Zn) como fonte. O experimento foi conduzido em casa de vegetação em DIC, com cinco doses de Zn (0, 1, 2, 4 e 8 mg kg-1 de solo), com quatro repetições. O experimento foi conduzido até a formação de grãos e foi realizada determinação de Zn por Espectrômetria de Absorção Atômica após digestão nitroperclórica e contagem do 65Zn nas partes da planta: parte aérea (PA) e panícula (P), para arroz e PA, vagem (V) e grão (G), para soja. Calculou-se a quantidade de Zn proveniente da fonte (Znpf) nas partes das plantas e o aproveitamento do Zn da fonte pelas culturas (Ap). Nas amostras de solo foram realizadas extrações por DTPA (ZnDTPA) e Mehlich-1 (ZnM1) em duas subamostragens (t1 e t2), antes da semeadura e florescimento, respectivamente. O fracionamento de Zn foi realizado em amostras de t2 nas frações: trocável (ZnTroc); ligado a carbonatos (ZnCarb); a matéria orgânica (ZnMO); a óxidos (ZnOxi) e residual (Znres). Adicionalmente, foi realizada análise do teor pseudo-total de Zn (ZnPST). Os dados obtidos foram submetidos à análise de variância pelo teste-F a 95 % de probabilidade, ajuste das variáveis em função das doses por regressões e teste de média e análises de correlações entre as principais variáveis respostas. O Zn acumulado total na planta se ajustou à regressão linear em função do aumento das doses, entretanto ao analisar as partes separadamente, só houve diferença entre as doses para a variável PA em ambas as culturas. O Znpf total nas plantas apresentou incremento com a adição das doses crescentes de Zn ao solo, entretanto, eu aproveitamento foi baixo, 12 e 8,75 % para arroz e soja, respectivamente. As doses de ZnCl2 adicionadas ao solo, aumentaram a concentração de Zn presente nas frações ZnTroc > ZnMO > ZnCarb, em ordem decrescente. O Zn total acumulado nas plantas de arroz e soja apresentam correlações crescentes para os extratores DTPA e M1 nas duas subamostragens (t1 e t2), em função das doses avaliadas. O Zn extraído pelo DTPA ou M1, apresentaram correlação significativa com o Zn extraído nas frações, na ordem decrescente, ZnTroc > ZnCarb > ZnMOZn deficiency in soil causes undesirable effects on agricultural production because the low availability of this micronutrient for plants promotes the decrease in enzymatic activity besides the deficiency of this element in food, which can lead to a state of malnutrition. Considering the problem of Zn in soil-plant system and its variations in soil compartments, it is important to evaluate its bioavailability and forms in soil which this element is associated. The objective of this study was to evaluate Zn bioavailability and compartmentalization in the soil, to the rice (Oryza sativa L.) and soybean (Glycine max L. Merrill) crops and evaluate the effect of Zn levels on nutrition and exportation of this nutrient by the crops. As test plant rice and soybeans were used to evaluate the effect of Zn rates on nutrition and the nutrient translocation to the grains. For this purpose, a sample of an Oxisol (FAO), an clay texture from Piracicaba (SP) region, was used and ZnCl2 (labelled with 65Zn) as a source. The experiment was conducted in a greenhouse in CRD, with five rates of Zn (0, 1, 2, 4 and 8 mg kg-1 soil), with four repetition. The experiment was conducted until the formation of grains and Zn analyzis were performed by Atomic Absorption Spectrophotometery after nitricperchloric digestion and 65Zn counting of parts: shoot (PA) and panicle (P) for rice and PA, beans pods (Pd) and grains (G) for soybeans. The amount of Zn derived from the source (Znpf) was calculated in the plant parts and the recovery of the Zn by the crops (Ap). In the soil samples, extractions were performed by DTPA (ZnDTPA) and Mehlich-1 (ZnM1) methods in two sub samples (t1 and t2) prior to seeding and flowering, respectively. The Zn fractionation was performed on samples of t2 in the fractions: exchangeable (ZnTroc); linked to carbonates (ZnCarb); to organic matter (ZnMO); to oxides (ZnOxi) and residual (Znres). Additionally, analysis of the pseudo-total content of Zn (ZnPST) was performed. Data obtained was subjected to analysis of variance by the F-test at 95% probability, adjusting the variables depending on the rates for regression and average test and analysis of correlations between the main variables. The total cumulative Zn in the plant set to the linear regression in terms of increasing rates, however when analyzing the parts separately, just the PA showed differences between doses, for both crops. The total Znpf increased with the increasing rates, however its recoveries were low, approximately 12% for rice and 8.75 % for soybean. The ZnCl2 rates in soil increased the Zn concentration in the fractions: ZnTroc > ZnMO > ZnCarb, in descending order. The total cumulative Zn in the rice and soybean plants are growing correlations for extractors DTPA and M1 for two sub samples (t1 and t2), depending on the rates evaluated. The Zn extracted by DTPA or M1 were significantly correlated with Zn extracted in fractions in descending order: ZnTroc > ZnCarb > ZnMO
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Nascimento, João Paulo Costa do. "Estudo dos Efeitos da Adição de Zn2+ e de Íons Terras-Raras nas Propriedades Dielétricas e de Luminescência da Matriz Cerâmica Lanbo4." reponame:Repositório Institucional da UFC, 2014. http://www.repositorio.ufc.br/handle/riufc/17473.
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NASCIMENTO, João Paulo Costa do. Estudo dos Efeitos da Adição de Zn2+ e de Íons Terras-Raras nas Propriedades Dielétricas e de Luminescência da Matriz Cerâmica Lanbo4. 2014. 81 f. Dissertação (Mestrado em química)- Universidade Federal do Ceará, Fortaleza-CE, 2014.Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-06-02T18:00:57Z No. of bitstreams: 1 2014_dis_jpcnascimento.pdf: 3867260 bytes, checksum: a43b3c86b0d84d66400215ddf8961d74 (MD5)
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With the rapid growth of wireless technologies, the telecommunications industry has constantly searching materials having excellent dielectric characteristics to be based on new devices. Due to this ever increasing demand, research for new and improved ceramic materials have occupied prominent place in the interest of the scientific community worldwide. The use of ceramic materials in search of fluorescent materials also has received attention, since such materials have several applications, such as lasers; light emitting diode (LED); as a source of light sensors; optical data storage and even in the medical field. In this work were studied the properties of LaNbO4 (LNO) matrix modified by adding of ZnO and also by doping with rare-earth ions erbium; ytterbium and thulium. The pure and doped LaNO4 samples were obtained by solid state reaction method using oxide precursor followed by heat treatment, while samples with ZnO was obtained by adding of determined quantity of latter on the LNO. The results of x-ray diffraction and Raman spectroscopy confirmed the formation of the ceramic phase LNO and the values of the dielectric properties obtained of this material were close to the values of the literature. The numerical simulation realized for LNO presented good gain value and a high efficiency, showing that this material can act as a DRA. About the addition of zinc, the x-ray diffraction showed that practically not occured significant changes in the diffraction pattern of LNO phase, being that regarding the dielectric properties was observed that the addition caused increase in the values of the permittivity and loss tangent nonlinearly with the increasing of the concentration of zinc. In the systems containing rare-earth ions the X-ray diffraction and Raman spectroscopy indicated that the dopant ions entered on the crystalline lattice of LNO phase. In the fluorescence were observed bands in the green and red region for the system with Er3+ and Yb3+ , concerning the transitions between the 4f orbitals of Er3+ . While for the system with Er3+ , Yb3+ and Tm3+ were observed bands in the ultraviolet region; blue; green; red and infrared originated of transitions that occur in the 4f orbitals of Er3 + and in the 4f orbitals of Tm3+.
Com o rápido crescimento de tecnologias sem fio, a indústria de telecomunicações tem buscado constantemente materiais que possuam excelentes características dielétricas para ser à base de novos dispositivos. Devido a essa demanda sempre crescente, pesquisas em busca de novos e melhores materiais cerâmicos têm ocupado cada vez mais lugar de destaque no interesse da comunidade científica mundial. O uso de materiais cerâmicos em busca de materiais fluorescentes também vem recebendo destaque, já que materiais desse tipo apresentam diversas aplicações, tais como lasers; diodo emissor de luz (LED); como fonte de luz sensores; estocagem de dados óticos e até mesmo na área médica. Neste trabalho foram estudados as propriedades da matriz cerâmica LaNbO4 (LNO) modificada pela adição de ZnO e também pela dopagem com íons terras-raras érbio; itérbio e túlio. As amostras de LNO e dopadas foram obtidas através do método reacional do estado sólido utilizando óxidos precursores seguido de tratamento térmico, enquanto as amostras com ZnO foram obtidas através da adição de determinada quantidade de massa deste sobre o LNO. Os resultados de difração de Raios-X e espectroscopia Raman confirmaram a obtenção da fase cerâmica LNO e os valores das propriedades dielétricas desse material foram próximos da literatura. A simulação numérica realizada para o LNO apresentou bom valor de ganho e alta eficiência, mostrando que esse material pode atuar como DRA. Quanto à adição de ZnO, a difração de Raios-X mostrou que praticamente não houve mudanças no padrão de difração da fase LNO. Já com relação às propriedades dielétricas foi observado que essa adição causou aumento nos valores de permissividade e tangente de perda de forma não linear com o aumento da concentração de zinco. Nos sistemas contendo íons terras-raras a difração Raios-X e espectroscopia Raman indicaram que os íons dopantes entraram na estrutura cristalina da fase LNO. Na fluorescência foram observadas bandas na região do verde e vermelho para as amostras com Er3+ e Yb3+, referentes às transições dos orbitais 4f do Er3+. Enquanto que para o sistema com Er3+, Yb3+ e Tm3+ foram observadas bandas nas regiões do ultra-violeta; azul; verde; vermelho e infravermelho originadas das transições dos orbitais 4f do Er3+ e 4f do Tm3+.
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Apicella, Fernandez Sergio. "Surface energy modification of metal oxide to enhance electron injection in light-emitting devices : charge balance in hybrid OLEDs and OLETs." Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-25097.
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Organic semiconductors (OSCs) present an electron mobility lower by several orders of magnitude than the hole mobility, giving rise to an electron-hole charge imbalance in organic devices such as organic light-emitting diodes (OLEDs) and organic light-emitting transistors (OLETs). In this thesis project, I tried to achieve an efficient electron transport and injection properties in opto-electronic devices, using inorganic n-type metal oxides (MOs) instead of organic n-type materials and a polyethyleneimine ethoxylated (PEIE) thin layer as electron transport (ETLs) and injection layers (EILs), respectively. In the first part of this thesis, inverted OLEDs were fabricated in order to study the effect of the PEIE layer in-between ZnO and two different emissive layers (EMLs): poly(9,9-dioctylfluorene-alt-benzothiadiazole) polymer (F8BT) and tris(8-hydroxyquinolinato) aluminum small molecule (Alq3), based on a solution and thermal evaporation processes, respectively. Different concentrations (0.80 %, 0.40 %) of PEIE layers were used to further study electron injection capability in OLEDs. After a series of optimizations in the fabrication process, the opto-electrical characterization showed high-performance of devices. The inverted OLEDs reported a maximum luminance over 104 cd m-2 and a maximum external quantum efficiency (EQE) around 1.11 %. The results were attributed to the additional PEIE layer which provided a good electron injection from MOs into EMLs. In the last part of the thesis, OLETs were fabricated and discussed by directly transferring the energy modification layer from OLEDs to OLETs. As metal oxide layer, ZnO:N was employed for OLETs since ZnO:N-based thin film transistors (TFTs) showed better performance than ZnO-based TFTs. Finally, due to their short life-time, OLETs were characterized electrically but not optically.
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Lima, Fabrício Ferreira. "Interação fósforo e zinco no mamoeiro ‘tainung 01’, em neossolo quartzarênico." reponame:Repositório Institucional da UFC, 2009. http://www.repositorio.ufc.br/handle/riufc/8487.
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LIMA, F. F. Interação fósforo e zinco no mamoeiro ‘tainung 01’, em neossolo quartzarênico. 2009. 46 f. Dissertação (Mestrado em Agronomia/Fitotecnia) - Centro de Ciências Agrárias, Universidade Federal do Ceará, Fortaleza, 2009.Submitted by Francisco Lacerda (lacerda@ufc.br) on 2014-07-02T20:54:56Z No. of bitstreams: 1 2009_dis_fflima.pdf: 604187 bytes, checksum: 55126ebb57d9a8f367e20196d5f375e8 (MD5)
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Carried out an experiment under field conditions, in Russas, CE, in order to evaluate the response of papaya (Carica papaya L.) to phosphorus and zinc fertilization under irrigation for one year of cultivation. The experiment was a NEOSSOLO QUARTZARÊNICO, using a randomized block design in a factorial design with five doses of P2O5 (105, 157.5, 210, 315 and 420 kg / ha) and five Zn (0, 3.12, 6.24, 12.48 and 18.72 kilograms / ha), with four replications, totaling 25 treatments and 100 plots. The variables were: P and Zn in soil from 0 to 20 and 20 to 40 cm depth, content of P and Zn in the leaf (petiole), plant height, girth and productivity. The nutrient content in soil and leaf, plant height and stem diameter were evaluated after six months of planting. Productivity was assessed on the first six months of production (1 st year of cultivation). Aside from stem diameter, all other variables were influenced by the levels of P2O5 and Zn, with interaction between the two nutrients in their effect on plant height, concentration of P and Zn in the soil, P concentration in leaves and productivity. The plant height increased linearly with increasing fertilizer with phosphorus and zinc. Phosphorus decreased availability of soil Zn, but did not influence the levels of Zn in the plant. Since the Zn influenced the content of P in the soil and the leaf. The highest yield was related to doses of 293 kg / ha P2O5 and 9.83 kg / ha of Zn.
Realizou-se um experimento em condições de campo, em Russas, CE, com o objetivo de avaliar a resposta do mamoeiro sob irrigação (Carica Papaya L.) à adubação com fósforo e zinco, durante um ano de cultivo em solo NEOSSOLO QUARTZARÊNICO. O delineamento experimental utilizado foi o de blocos ao acaso, em um esquema fatorial 5 x 5 (105; 157,5; 210; 315; e 420 kg de P2O5/ha) e (0; 3,12; 6,24; 12,48 e 18,72 kg de Zn/ha), com quatro repetições. As variáveis avaliadas foram: conteúdos de P e Zn no solo nas camadas de 0 a 20 e 20 a 40 cm de profundidade, teor de P e Zn na folha (pecíolo), altura da planta, circunferência do caule e produtividade. Os teores dos nutrientes no solo e na folha, altura de planta e diâmetro do caule foram avaliados após seis meses do plantio. A produtividade avaliada foi referente aos seis primeiros meses de produção (1° ano de cultivo). Com exceção do diâmetro do caule, todas as outras variáveis foram influenciadas P (P2O5) e Zn, havendo interação entre os dois nutrientes no seu efeito sobre a altura da planta, concentração de P e Zn no solo, teor de P na folha e produtividade. A altura da planta aumentou linearmente com o incremento da adubação com fósforo e zinco. O fósforo diminuiu a disponibilidade de Zn no solo, porém não influenciou os teores de Zn na planta. Já o Zn influenciou os conteúdos de P tanto no solo como na folha. A máxima produtividade foi relacionada às doses de 293 kg/ha de P (P2O5) e 9,83 kg/ha de Zn.
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Pouillard, Violette. "En captivité. Politiques humaines et vies animales dans les jardins zoologiques du XIXe siècle à nos jours : ménagerie du Jardin des Plantes, zoos de Londres et Anvers." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209127.
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Suivant les récents développements historiographiques dans le champ de l’histoire des animaux, cette thèse aborde l’histoire des jardins zoologiques du côté des bêtes elles-mêmes. Elle examine donc non seulement les politiques humaines de gestion des animaux de zoo, mais aussi leurs influences sur les corps et les comportements des animaux, et leurs évolutions mutuelles. L’examen débute à la fondation du jardin zoologique, c’est-à-dire au moment de la création de la ménagerie parisienne du Jardin des Plantes en 1793, et se centre, outre sur cette institution originelle, sur le jardin zoologique de Londres, créé en 1828, et celui d’Anvers, fondé en 1843.
Pour écrire l’histoire des animaux de zoo, la thèse mobilise une méthodologie qui mêle des indicateurs descriptifs – témoignages sur les corps et comportements animaux, sur les infrastructures de captivité, sur les soins et l’alimentation dont bénéficient les bêtes, – et quantitatifs – étude sérielle sur la longue durée des entrées et sorties d’animaux ainsi que des longévités des primates et des grands félins. L’évolution de ces différents indices est examinée au sein d’un cadre chronologique régi par les politiques des gestionnaires de zoos. Ainsi, après une première partie débutant à la fondation des institutions étudiées, une seconde s’ouvre au début du XXe siècle, alors que le marchand allemand Carl Hagenbeck ouvre en 1907 un zoo privé à Stellingen, près de Hambourg, qui popularise un nouveau type de présentation des bêtes, par lequel celles-ci sont exposées durant la journée en plein air et séparées du public par des fossés. Enfin, une troisième partie s’amorce à partir des années 1950, lorsque les zoos s’attellent à la mise en œuvre d’une nouvelle fonction, celle de protection des espèces ex situ, s’ajoutant aux trois autres traditionnellement endossées (récréative, éducative, scientifique).
L’examen des vies des bêtes sous l’influence des politiques humaines aboutit à élaborer une nouvelle chronologie des zoos, qui distingue un long XIXe siècle, dévoreur de vies animales ;une seconde phase, hygiéniste, à partir de l’entre-deux-guerres, caractérisée par les volontés des gestionnaires de rationaliser les conditions de captivité, mais dont les incidences sur les vies animales sont toutefois réduites ;enfin une troisième, attentive aux animaux, du milieu des années 1970 à nos jours, qui permet la naissance d’une nouvelle économie animale des zoos, qui voit l’atténuation des ponctions en milieu naturel pour la plupart des taxons (spécifiquement les mammifères et les oiseaux).
Ce faisant, l’étude met aussi en évidence, à rebours des discours finalistes de l’historiographie officielle, des permanences, immanentes à la captivité des animaux dans le contexte des zoos. Il s’agit d’une part de l’expression par les bêtes de comportements anormaux dans des proportions qui dépassent le niveau anecdotique ;il s’agit d’autre part de l’approvisionnement en milieu naturel, qui, bien qu’en déclin dans le contexte du bouleversement de l’économie animale, persiste jusqu’à nos jours en nombre important pour les taxons moins considérés, soit les poissons et les invertébrés, et se réincarne en de nouveaux avatars pour les autres (ponctions dans le cadre des programmes de protection, captures scientifiques, )./
Following in the footsteps of recent developments in the French historiography, this dissertation aims at balancing the attention given to humans and animals. The research therefore focuses on human policies concerning the management of animals kept in zoological gardens, as well as on their consequences on the bodies and behaviors of animals, and on mutual influences between humans and animals.
The study begins with the birth of the zoological garden, i.e. the creation of the Jardin des Plantes Menagerie in 1793, and focuses on this institution as well as on the London Zoo, created in 1828, and the Antwerp Zoo (1843).
In order to write the history of zoo animals, the method uses both descriptive indicators – testimonies on animals bodies and behaviors, on captive environments, on animal cares, handling and food, – and quantitative indicators – long-term study of the arrivals and departures, births and deaths of animals and of the longevity of Primates and Pantherinae in captivity. The evolution of these indicators takes place in a chronological framework based on the policies designed to manage zoo animals. The first part begins with the foundation of the zoological gardens. The second one starts at the beginning of the 20th century, when German dealer Carl Hagenbeck opened a zoo in Stellingen, near Hamburg (1907) which popularized a new way to display the animals, in open-air enclosures separated from the public by ditches. The third part starts in the 1950’s, when zoos implemented a new function, one of ex situ conservation, in addition to their other traditional recreative, educative and scientific missions.
This study of animal lives under human influence results in a new chronology of zoological gardens, discerning a long 19th century, that consumed animal lives, a second phase, hygienist, from the interwar period, marked by the managers’ willingness to rationalize the conditions of captivity, without much influence on animals lives and longevity, and a third one, from the mid-1970’s to the present time, characterized by increased attention to zoo animals and their well-being, allowing the birth of a new animal economy of zoological gardens, by which in situ captures decline for most taxa (specifically mammals and birds).
The dissertation also shows, in opposition with the finalist discourses of the official historiography, somes continuities, immanent to animal captivity in the context of zoological gardens. Abnormal behaviors in animals especially appear in proportions exceeding the anecdotal level. Another important phenomenon pointing to continuities is the collecting in the wild which, although it declined at the same rhythm that the new animal economy developed, has persisted to this day, profusely for the least considered taxa (fishes and invertebrates), and resurfacing in new iterations for mammals, birds, reptiles and amphibians (capture for purposes of conservation, for scientific collecting, ).
Doctorat en Histoire, art et archéologie
info:eu-repo/semantics/nonPublished
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Schiavo, Simona. "Toxic effect of different metal bearing nanoparticles (ZnO NPs, TiO2 NPs, SiO2 NPs, Ag NPs) toward marine phytoplankton." Tesi di dottorato, 2016. http://www.fedoa.unina.it/10837/1/schiavo_simona_28.pdf.
Повний текст джерелаАнотація:
Abstract
The advent of nanotechnology and the commercialization of several nanoparticle-containing-products call to a thorough assessment of the environmental risks derived from the exposure to these new materials. The most important criticisms of new nano-structured materials are represented by the emerging properties, the absence of a dedicate regulation, the increasing world-market, the implementation of the application fields. At “nano” size, materials show different physicochemical properties compared to the same material of larger size (bulk material), particularly with respect to conductivity, density, hardness, surface area and surface layer composition. At the same time, these novel properties of nanoparticles (NPs) generate special concerns about their potential hazards to humans and other organisms when released into the environment.
In this context, studies on the potential toxicity of NPs in different biological systems are urgently needed in order to define adequate guidelines for toxicity studies and to harmonize the production of new and safe materials. Since marine environment represents the ultimate sink for any materials discharged into the environment, the effect on marine organisms should be considered a critical point in the definition of NP toxicity.
In coastal ecosystems, microalgae play a key role as primary producers and, being at the base of the aquatic food web, any modification of their growth could affect higher trophic levels additionally, phytoplankton represents an excellent aquatic model for the study of the effects of pollutant exposure at population level due to a short generation time and high sensitivities. For all these reasons, they could be considered as key targets for NPs toxicity.
In this PhD thesis marine phytoplankton have been used in order to assess the potential toxicity and the mode of action of different metal bearing NPs: ZnO, SiO2, TiO2, and Ag. Several endpoint such as population growth inhibition, microscopy observations, cytotoxicity and evaluation of DNA damage are evaluated in the aim of understand the different interaction among algae/NPs and how this interaction could be related to the toxic mechanisms.
The comparison among the tested nanomaterial toxicity pattern highlighted that the algae population growth inhibition occurred through specific pathways related to different physicochemical NP behavior in seawater.
ZnO seems to exert its toxic action upon algae by a punctual and continuous ion release from aggregates in proximity of algae cell wall. In addition, in the case of Ag NPs, the toxicity is related to the ion release but to a greater extend respect to ZnO NP. For SiO2 a cascade of effects (ROS production-DNA damages-growth inhibition) are evidenced suggesting a toxicity starting from oxidative stress generation. TiO2, instead, firstly acts on DNA structure and then, being not soluble in seawater, after internalization during cell division or cell wall destruction, gives place to activation of cellular signals destabilizing DNA structure. These results underline the importance and the necessity of further long-term toxicological experiments. In addition, more attention should be paid on how the toxic effects induced by NPs has impact on the food chain.
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CHAUDHARY, SHRUTIKA. "PHYCOSYNTHESIS OF ZINC OXIDE NANOPARTICLES FROM CHLORELLA SP. AND ITS CHARACTERIZATION AND APPLICATION." Thesis, 2023. http://dspace.dtu.ac.in:8080/jspui/handle/repository/19899.
Повний текст джерелаАнотація:
Chlorella sp. are bio-factory of several bioactive compounds which aid in the formation
of many nanoparticles (NPs). The bioactive compounds present in algae are fucoxanthin,
carotenoid, phycocyanin, etc. These bioactive compounds help in the diminution of
metal precursor to their respective metal/metal oxide NPs. NPs synthesized from
Chlorella sp. are biocompatible, ecofriendly, and non-toxic. “Phycosynthesis” is the
term given to the synthesis NPs from algal species. ZnO NPs are very versatile because
they possess biomedical properties like antimicrobial, anti-cancerous, and anti-diabetic
activity. Moreover, they also have the ability to degrade pollutants such as heavy metals
and dyes. In this report, biological synthesis ZnO NPs is performed from extract of
Chlorella sp. and characterized using UV-vis spectrophotometer, Zeta sizer to identify
the charge and the hydrodynamic size of the ZnO NPs. These ZnO NPs were then used
to identify their antibacterial property against E.coli.
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Hsu, Chih-Ting, and 許志廷. "Utilizing Multiphoton Microscopy to Investigate Chemically Enhanced Transdermal Delivery Depth of ZnO NPs." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/64481481198223782591.
Повний текст джерелаАнотація:
碩士國立臺灣大學
物理研究所
97
Multiphoton microscopy , using longer wavelength of near infrared light as excitation light source has deeper penetration and less photodamage.Besides , it can capable all visible autofluorescence and second harmonic generation , making us observe specimens through autofluorescence and second harmonic generation directly without slicing and dying . Hence , I hope to apply this technology of nonlinear optical microscopy to observe and analysize in skin . The aim of this research is to utilizing multiphoton microscopy to investigate chemically enhanced transdermal delivery depth of ZnO NPs and the distribution of ZnO NPs in the stratum corneum . First , we chose the nude mice skin to avoid the autofluorescence of hair . The skin was incubated in the diffusion cell with four diffusion solution for 12 hours . Then we used the data to investigate the penetration depth and the distribution of ZnO NPs . We also can quantify the transport properties of the ZnO NPs under chemical enhancers . In this work, the results demonstrate that ZnO NPs mainly distribute in the stratum corneum . The chemical enhancements didn’t increase the penetration depth obviously. ZnO NPs penetrate beyond SC, not into the dermis.
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Tang, Tsung-Yeh, and 湯宗曄. "Preparation and photocatalytic activity of Ag2O nps and Ag2O/Ag-ZnO nano-composites." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/48145774380481253382.
Повний текст джерела
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Chia-ChengYeh and 葉家呈. "Localized surface-plasmon effects of Au NPs on UV electroluminescence properties of n-ZnO/p-GaN heterojunction light emitting diodes." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/78481282681123973547.
Повний текст джерелаАнотація:
碩士國立成功大學
光電科學與工程學系
104
This paper demonstrates that both intensities of photoluminescence (PL) and electroluminescence (EL) from the band edge emission of ZnO submicron spheres can be improved by the use of localized surface-plasmon resonance (LSPR) Au nanoparticles (NPs). Conversely, the use of LSPR reduces the green emission from the surface defect of ZnO. The origin of such luminescence enhancement is attributed to the LSPR, where electrons transfer between a conduction band and defect level through the LSPR. Time-resolved PL measurement results reveal that the spontaneous rate is increased as a result of the coupling between ZnO excitons and Au NPs LSPR. The other reason for the enhancement of PL from the near-band-edge emission of ZnO is the exciton-LSP coupling between Au NPs and ZnO. A six-fold ultraviolet EL enhancement was achieved from the Au NPs decorated device. Different deposited sequences of Au NPs in an n-ZnO/p-GaN layer were made to understand the selective enhancement of EL. Enhancement such as the ones demonstrated in this paper should be considered in the future when designing the highly efficient solid state emitters.
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Panigrahi, Sharbani. "Structure, microstructure and physical properties of ZnO based nanocomposites." Thesis, 2019. http://hdl.handle.net/10821/8317.
Повний текст джерелаАнотація:
thesis entitled “Structure, microstructure and physical properties of ZnO
based nanocomposites” deals mainly with the structural, photoluminescence and
photoconductivity properties of different ZnO-based nanocomposite materials in various
forms. These properties have been discussed by analyzing the role of defect states and band
alignment of the composite materials in controlling the optical and opto electrical properties of the materials. Among all the wide band gap semiconductors, nanostructured ZnO (Eg ̴ 3.37 eV) has been paid a great attention by the scientific world due to its high exciton binding energy (60 meV) which is much higher as compared to GaN and ZnSe having the same semiconductor properties of ZnO and also because its ability to grow in different forms of nanostructures by cheaper synthesis methods. In this work, the nanocomposite structures have been grown by using different chemical synthesis processes and the properties of the composite nanostructures have been compared to the as-grown ZnO nanostructures synthesized by aqueous chemical growth (ACG) and sol-gel techniques. The characterizations of the as-grown and nanocomposite samples have been done using the techniques such as xray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), photoluminescence (PL), photoconductivity
measurements etc. The entire thesis consists of ten (10) chapters. It starts with a general introduction and ends with a summary of the results. A brief review on the past and recent works on ZnO based nanocomposites reported in the literature has been presented before the respective chapters. Experimental techniques used for characterizations of the samples have also been described in detail.The research was carried out under the supervision of Prof. Durga Basak of the Solid State Physics division under SPS [School of Physical Sciences]
The research was being conducted under CSIR fellowship and research grant
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"Functional epigenetics identifies novel KRAB-ZNF tumor suppressors in ESCC, NPC and multiple tumors." Thesis, 2010. http://library.cuhk.edu.hk/record=b6075041.
Повний текст джерелаАнотація:
First, expression profiling of ZNFs with CpG islands at 10 clusters of Chr19 was examined in a panel of NPC and ESCC cell lines by semi-quantitative RT-PCR, with adult normal tissues - larynx and esophagus as controls. Several down-regulated genes were identified, and I further focused on 5 candidates: ZNF382, ZNF545, ZFP30, ZNFT1 and ZNFT2. These genes were frequently downregulated in NPC, ESCC, lung, gastric, colon and breast carcinomas. Their promoters were frequently methylated in multiple downregulated cell lines but less in non-tumor cell lines as revealed by methylation-specific PCR (MSP) and bisulfite genomic sequencing (BGS). Their expression could be restored by pharmacologic or genetic demethylation, suggesting that DNA methylation was directly involved in their silencing. The frequent methylation of these genes indicated they could act as potential biomarkers.In conclusion, several novel candidate TSGs epigenetically silenced in tumor cells were identified in this study. Their downregulation by promoter methylation was tumor-specific, which could be use as epigenetic biomarkers for diagnosis.
More functional studies were done for ZNF382 and ZNF545, I found that ectopic expression of ZNF382 and ZNF545 in tumor cells lacking endogenous expression could inhibit tumor cell clonogenicity, proliferation and induce apoptosis. I found that ZNF382 suppressed tumorigenesis through mediating heterochromatin formation, as ZNF382 was revealed to be co-localized and interacts with heterochromatin protein. For ZNF545, I found that it is a transcriptional repressor. I further showed that ZNF545 was located in the nucleus and sequestered in the nucleolus. ZNF545 could inhibit tumorigenesis at least partially through downregulating the transcription of target genes or regulating nucleolus function such as ribosome biogenesis.
The development of a tumor from a normal cell is a complex and multi-step process. A large number of oncogenes, tumor suppressor genes (TSGs) and signal transduction pathways are involved in this process. Tumor-specific methylation of TSGs in multiple tumors indicated that it could be used as epigenetic biomarker for molecular diagnosis and therapeutics.
The functions of KRAB-containing proteins are critical to cell differentiation, proliferation, apoptosis and neoplastic transformation. A large number of ZNF genes are located in 10 clusters at chromosome 19. Some of the KRAB-ZNF may function as potential TSGs with epigenetic alterations. Thus, I try to identify silenced novel KRAB-ZNF candidate TSGs through screening chromosome 19.
Cheng, yingduan.
Adviser: Tao Qian.
Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: .
Thesis (Ph.D.)--Chinese University of Hong Kong, 2010.
Includes bibliographical references (leaves 110-136).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
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Δροσερός, Νικόλαος. "Οπτικές ιδιότητες κβαντικών τελειών CuInS2 /ZnS με τεχνικές φασματοσκοπίας σταθερής κατάστασης και χρονικής ανάλυσης". Thesis, 2015. http://hdl.handle.net/10889/8636.
Повний текст джерелаАнотація:
Στην παρούσα Ειδική Ερευνητική Εργασία ερευνώνται οι οπτικές ιδιότητες των νανοκρυσταλλικών κβαντικών τελειών CuInS2/ZnS, γνωστές ως CIS/ZnS QDs, τόσο με τη χρήση φασματοσκοπίας σταθερής κατάστασης όσο και με τη χρήση φασματοσκοπίας χρονικής ανάλυσης με την τεχνική Time Correlated Single Photon Counting. Ειδικότερα, διερευνώνται οι μηχανισμοί που εμπλέκονται στη διαδικασία της εκπομπής φωτός, η επίδραση που έχει η πολικότητα του διαλύτη και η συγκέντρωση των κβαντικών τελειών, όταν είναι διαλυμένες εντός διαλύματος, καθώς και η αλληλεπίδραση μεταξύ των κβαντικών τελειών όταν είναι εναποτιθέμενες σε υμένια, είτε με την τεχνική drop-casting είτε με spin-coating.
Τόσο η αύξηση της συγκέντρωσης των κβαντικών τελειών όσο και η αύξηση της πολικότητας του διαλύτη προκάλεσε τη μετατόπιση του εξιτονικού ώμου και του μήκους κύματος μέγιστης εκπομπής προς το ερυθρό, στα φάσματα σταθερής κατάστασης. Επίσης η μετατόπιση της φωτοφωταύγειας των CIS/ZnS QDs προς το ερυθρό ήταν μεγαλύτερη στα υμένια που είχαν παρασκευασθεί με την τεχνική drop-casting από τα υμένια με το ίδιο υπόστρωμα που είχαν παρασκευασθεί με την τεχνική spin-coating.
Με χρήση φασματοσκοπίας χρονικής ανάλυσης, ανιχνεύθηκε η ύπαρξη τριών μηχανισμών στα διαλύματα με χρόνους ζωής 1-3, 20-40 και 200-300 ns, ενώ στα υμένια προστέθηκε ένας επιπλέον μηχανισμός με χρόνο ζωής από μερικές εκατοντάδες ps έως 4 ns. Ο χαρακτήρας της αποδιέγερσης των QDs στα υμένια κυμαίνεται μεταξύ διεκθετικού και τετραεκθετικού ανάλογα με το δείγμα και το μήκος κύματος ανίχνευσης. Το περίεργο χαρακτηριστικό του νέου μηχανισμού που ανιχνεύθηκε στα υμένια είναι ότι γίνεται πιο γρήγορος και πιο αποδοτικός καθώς το μήκος κύματος ανίχνευσης αυξάνει. Ένας παρόμοιος μηχανισμός δεν έχει αναφερθεί σε άλλες εργασίες με CIS/ZnS QDs, ενώ έχει αναφερθεί σε παλιότερες εργασίες με PbS QDs τόσο σε διαλύματα όσο και σε στερεά υμένια. Η μετατόπιση των πυκνών υμενίων προς το ερυθρό σε σχέση με τα αραιά αποτελεί ένδειξη της ύπαρξης μεταφοράς ενέργειας μεταξύ QDs διαφορετικών μεγεθών.In this Master Thesis, the optical properties of CuInS2/ZnS nanocrystal quantum dots are investigated. For this purpose both steady state and time resolved spectroscopy, specifically the Time Correlated Single Photon Counting technique, were used. The photoluminescence properties of CuInS2/ZnS quantum dots, commonly known as CIS/ZnS QDs, either dissolved in solutions of different concentrations and solvent polarities or deposited on films made by spin-coating or drop-casting are studied. Either in the absorption and the photoluminescence steady state spectra, a red-shift both in the excitonic transition and the wavelength of the maximum intensity was observed as the concentration of the CIS/ZnS QDs or the polarity of the solvent increased. In films, a red-shifted photoluminescence spectrum is observed for films made by drop-casting compared to those prepared by spin-coating, having the same substrate material. By using time-resolved photoluminescence spectroscopy a three-exponential decay was observed in solutions, with time constants 1-3, 20-40 and 200-300 ns, while decays in films, apart from the three mechanisms also observed in solutions, also exhibit a fast decay component with a lifetime varying from some hundreds of ps until 4 ns. The attitude of the decay in films varies from two-exponential to four-exponential and it depends on the samples and the detection wavelength. The strange characteristic of the new mechanism which was detected in films is that its lifetime becomes shorter and its pre-exponential factor increases with the detection wavelength. To the best of our knowledge, such a faster decay as the emission wavelength increases has never been reported for CIS/ZnS QDs, but it has been reported for PbS QDs either diluted in solution or deposited in polymeric matrices. The time resolved photoluminescence spectra in the drop-casted films experience a larger transient red-shift than the spin-coated ones, indicative of a possible energy transfer among adjacent QDs with different diameters.
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Marques, Carolina Fidalgo. "Perovskite Photovoltaic Materials: towards a flexible and low cost solar cell technology." Master's thesis, 2017. http://hdl.handle.net/10362/23414.
Повний текст джерелаАнотація:
The exploitation of solar energy has become a necessity for sustainable development. One of the approaches has been the use of photovoltaic materials to convert this never-ending energy source in electrical energy. For this approach to be reliable, it ought to combine high efficiency with low production costs, while also promising flexible devices. Perovskite structured compounds act as the light harvesting material in solar cells and can be produced using simple methods such as solvent-engineering and spin coating. This work focuses on the study of perovskite compounds ABX3, where A is methylammonium or caesium cations, B is a lead cation and X is a halide ion such as bromine, chlorine and iodine. These films were produced via spin coating and the solvent-mix used was DMF:DMSO in different ratios (2:3, 3:2 and 4:1). The influence of toluene dropping during the spinning process was also studied. The careful tuning of these processes allowed the formation of poly-crystalline perovskite films, deposited on top of Glass/FTO/ZTO-NPs, that presented optical absorbance values between 80-90% and optical bandgaps of 1.5 eV for MAPbI3 and 1.7 eV for MAPbI2Br0.85Cl0.15, as expected from the state-of-art materials.
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Costa, Cristiana Andreia Cruchinho da. "A eficácia da educação ambiental nos campos de férias em Portugal - O caso de estudo do ATL do Zoo." Master's thesis, 2019. http://hdl.handle.net/10362/76562.
Повний текст джерелаАнотація:
A Educação Ambiental (EA) tem vindo a ganhar importância ao longo dos anos e a experiência demonstra que é essencial o envolvimento de toda a comunidade, não ficando confinada ao ensino formal. Tendo em consideração que os campos de férias são locais que proporcionam aprendizagens ao mesmo tempo que divertem os jovens, esta dissertação tem dois objetivos:
1. Investigar os métodos de EA nos campos de férias em Portugal;
2. Avaliar a eficácia da EA praticada no campo de férias ATL do Zoo – Verão 2018, relativamente à alteração de atitudes e comportamentos ambientais dos participantes.
Recorreu-se a uma metodologia baseada em questionários: um questionário para os campos de férias, ao qual responderam 42 entidades; questionários para o ATL do Zoo, envolvendo 425 participantes e 70 Encarregados de Educação (EE). O questionário destinado aos participantes contém 25 itens sobre atitudes e comportamentos ambientais, tendo sido aplicado em dois momentos: antes e depois da frequência do campo de férias. O questionário para os EE permitiu aferir as mudanças de atitudes e comportamentos ambientas.
Os resultados permitiram concluir que existe um esforço por parte dos organizadores de campos de férias para abordar temáticas ambientais nas suas atividades, mesmo que o “ambiente” não seja o foco dos seus programas. Mas a avaliação de eficácia dessas atividades é praticamente inexistente. A avaliação de eficácia realizada no ATL do Zoo permitiu concluir que este proporciona alterações positivas em temas como a redução da utilização de plástico descartável, a separação de resíduos e a diminuição de consumo de alimentos com impacto negativo nos seres vivos. O facto de as atividades serem desenvolvidas numa “sala de aula viva” proporciona a aproximação dos jovens com a Natureza.
Espera-se que os resultados obtidos nesta dissertação contribuam para a dinamização de atividades de EA nos campos de férias e da respetiva avaliação de eficácia, contribuindo para a mudança positiva de atitudes e comportamentos de quem as recebe, objetivo último da EA.
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Nascimento, Guilherme João Rodrigues. "O planeamento e gestão de risco no projeto de migração de armazéns na NOS, S.A." Master's thesis, 2016. http://hdl.handle.net/10071/13222.
Повний текст джерелаАнотація:
Classificação JEL: L810 - Retalho e Grossista; Armazenagem; Comércio Online e M110 - Gestão de ProduçãoAtualmente, existe uma grande pressão sobre os mercados e sobre as empresas para que consigam dar resposta às exigências de uma economia cada vez mais competitiva. Neste sentido, as fusões permitem aumentar a diversificação e capacidade de resposta a estas exigências. O trabalho que aqui se apresenta resulta da fusão (ZON e Optimus) que originou a NOS, onde a integração de armazéns foi um marco crucial. A Migração de Armazéns é um projeto complexo e com um elevado nível de risco devido ao volume de stock a movimentar bem como ao fato de não haver paragem da normal operação logística. Logo, um planeamento e gestão eficazes são fundamentais para o sucesso deste projeto. Assim, os objetivos deste trabalho são proceder à Iniciação e Planeamento do Projeto de “Migração de Armazéns” com especial enfoque no Planeamento e Gestão do Risco e comparar o Planeamento com a Execução. No que respeita à metodologia foram realizadas entrevistas, focus group e revisão narrativa da literatura recorrendo posteriormente a metodologias de identificação e planeamento do risco como o Diagrama de Ishikawa, a Risk Breakdown Structure, a Matriz de Probabilidade e Impacto ou a Árvore de Decisão. Como resultados, de relevar que não existiu impacto para a satisfação do consumidor, o cronograma sofreu uma ligeira adaptação e orçamento não revelou desvios negativos. Relativamente ao risco, o facto de ter sido efetuado um planeamento detalhado, tendo sido delineadas e aplicadas estratégias diferenciadas para os riscos considerados médios e altos, foi um dos fatores de sucesso do projeto.
Currently there is a great pressure on markets and companies so they can meet the demands of an economy increasingly competitive. In this sense, mergers occur more frequently, allowing increase diversification and responsiveness to these requirements. The work presented here is the result of the merger between ZON and Optimus resulting in NOS, here the integration of warehouses was a crucial milestone. The Warehouses Migration is a complex project with a high level of risk due to the volume of stock to be migrated as well as the fact that business as usual does not stop. As such, planning and affective management are critical to the sucess of this project. The objectives of this work are to proceed Initiation and Planning “Warehouse Migration” Project with special focus on Risk Management and Planning and compare the planning with the effective execution. With regard to the methodology there were conducted exploratory interviews, focus group and literature narrative review using subsequent risk identification and planning methods such as Ishikawa Diagram, the Risk Breakdown Structure, Probability-Impact Matrix and Decision Tree. As results, we reveal that there was no impact to the final consumer, the schedule suffered a slight adaptation and the budget revealed no negative deviations. As regards to risk, the fact that it was made a careful planning of it, having been designed and implemented different strategies to the risks considered medium and high, was one of the factors that contributed to Warehouse Migration Project had been success.
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Andrade, Inês di Giovine Fernandes Freire de. "A derrogação da obrigação de lançamento de oferta pública de aquisição em caso de fusão : o caso NOS." Master's thesis, 2018. http://hdl.handle.net/10400.14/29128.
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