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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Efeito da adi??o de feldspato e/ou res?duo de caulin em formula??es ? base de argila il?tica

Castro, Raimundo Jos? de Sousa 16 November 2010 (has links)
Made available in DSpace on 2014-12-17T14:07:06Z (GMT). No. of bitstreams: 1 RaimundoJSC_TESE.pdf: 1754370 bytes, checksum: 88d2811dd20d4c281cc4bc5a58cfc6fa (MD5) Previous issue date: 2010-11-16 / The red pottery industry in Piau? state is well developed and stands out at the national context for the technical quality of its products. The floor and wall tile industry, however, is little developed since the state has only one company that produces red clay-based ceramic tiles. This thesis aims at using the predominantly illitic basic mass of the above mentioned industry, with the addition of feldspar and/or kaolin residue in order to obtain products of higher technical quality. Kaolin residue consists basically of kaolinite, muscovite mica and quartz; the feldspar used was potassic. In this experiment, basic mass (MB) was used for experimental control and fifteen formulations codified as follows: F2, F4, F8, F16, F32, FR2, FR4, FR8, FR16, FR32, R2, R4, R8, R16 and R32. All raw materials were dry-milled, classified, formulated and then humidified to 10% water. Thereafter, test samples were produced by unixial pressing process in a rectangular steel matrix (60.0 x 20.0 x 5.0) mm3 at (25 MPa). They were fired at four temperatures: 1080?C, 1120?C, 1160?C, with a heating rate of 10?C/min during up to 10 min in an electric oven, and the last one in an industrial oven with a peak of 1140?C, aim ing to confirm the results found in laboratory and, finally, technological tests were performed: MEA, RL, AA, PA, TRF and PF. The results revealed that the residue under study can be considered a raw material with large potential in the industry of red clay-based ceramic tiles, since the results found both in laboratory and in the industry have shown that the test samples produced from the formulations with up to 4% feldspar and those produced with up to 8% feldspar and residue permitted a reduction in the water absorption rate and an increase in the mechanical resistance while those samples produced with up to 4% residue had an increase in the mechanical resistance when compared to those produced from the basic mass and that the formulation with 2% feldspar and residue presented the best technological properties, lowering the sintering temperature down to 1120?C / A ind?stria de cer?mica vermelha do Piau? ? bem desenvolvida e se destaca no contexto nacional pela qualidade t?cnica de seus produtos. J? a ind?stria de revestimento pouco se desenvolveu, visto que o estado possui uma ?nica empresa que produz revestimento de base argilosa vermelha. Esta tese tem por objetivo utilizar a massa b?sica predominantemente il?tica da ind?stria citada, adicionando ? mesma feldspato e/ou res?duo de caulim com o prop?sito de obter produtos de melhores qualidades t?cnicas. O res?duo caulim ? constitu?do basicamente de caulinita, mica moscovita e quartzo; o feldspato utilizado foi o pot?ssico. Para este experimento, utilizou-se a massa b?sica (MB) para controle experimental e quinze formula??es assim codificadas: F2, F4, F8, F16, F32, FR2, FR4, FR8, FR16, FR32, R2, R4, R8, R16 e R32. Todas as mat?rias-primas foram mo?das a seco, caracterizadas, formuladas, depois umidificadas a 10% com ?gua. Em seguida, foram confeccionados corpos-de-prova por prensagem uniaxial em matriz retangular de a?o (60,0 x 20,0 x 5,0) mm? a (24 MPa), os quais foram queimados em quatro temperaturas: 1080?C, 1120?C, 1160?C, com taxa de aqu ecimento de 10?C/min e patamar de 10 min em forno el?trico, e a ?ltima em forno a rolo industrial e pico de 1140?C com o objetivo de validar os resultados encontra dos em laborat?rio; por ?ltimo, foram realizados ensaios tecnol?gicos: MEA, RL, AA, PA, TRF e PF. Os mesmos mostraram que o res?duo estudado pode ser considerado como mat?riaprima de grande potencial para a ind?stria de pisos e revestimentos cer?micos de base argilosa vermelha, j? que tanto os resultados encontrados em laborat?rio como na ind?stria mostram que os corpos-de-prova produzidos a partir das formula??es com feldspato at? 4% e os produzidos com feldspato e res?duo at? 8% permitiram uma redu??o da absor??o de ?gua e aumento da resist?ncia mec?nica, sendo que os corpos-de-prova produzidos com at? 4% de res?duo tiveram aumento da resist?ncia mec?nica, quando comparados aos corpos-de-prova produzidos a partir da massa b?sica e que a formula??o com 2% de feldspato e res?duo apresentou melhores propriedades tecnol?gicas, reduzindo a temperatura de sinteriza??o para 1120?C
22

A influ?ncia da adi??o de caulim, quartzo e feldspato pot?ssico na formula??o de massas cer?micas para telhas: Modelo estat?stico

Ara?jo, Janiara Ferreira de 13 November 2008 (has links)
Made available in DSpace on 2014-12-17T14:57:49Z (GMT). No. of bitstreams: 1 JaniaraFA.pdf: 946913 bytes, checksum: 7a2683c43f2b9a59eaca617cf3e52563 (MD5) Previous issue date: 2008-11-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The production of roof tiles in the state of Rio Grande do Norte accounts for around 60% of the total of ceramic pieces produced. There is a need for investment to improve quality and productivity, thereby promoting technological innovations. Accordingly, the aim of this study is to determine the effect of kaolin, potassium feldspar and quartz in two standard formulations, as well as the effect of sintering temperature on the technological properties of linear firing shrinkage, water absorption and bending rupture stress, by fitting the statistical model and using multiple linear regression to assess the relationship between technological properties and independent variables. The raw materials were characterized using the following techniques: X-ray fluorescence (XRF), X-ray diffraction (XRF), rational analysis (RA), differential thermal analysis (DTA) and granulometric analysis (GA). The test specimens were compacted by uniaxial pressure (25 MPa), dried in a stove at 110 ?C for 24 hours and sinterized at 850 ?C, 950 ?C and 1050 ?C and held isothermal for 30 minutes. The results obtained indicate that the addition of kaolin to two standard formulations (M and R) promoted a reduction in water absorption values and an increase in bending rupture stress values. The sintering temperatures for group M that resulted in the lowest linear firing shrinkage and water absorption values were 850 ?C and 950 ?C, respectively, and the highest bending rupture stress values were reached at a temperature of 950 ?C. In the case of group R, the sintering temperature that obtained the lowest water absorption and linear firing shrinkage values was 850 ?C, and the highest bending rupture stress values were attained at a temperature of 1050 ?C. This work explains the statistical approach used to fit the model that describes the relationship between the technological properties and percentage of kaolin, quartz and feldspar, as well as the models that enable predictions, provided that the lower and upper limits of the percentage of clay minerals, flux and quartz used in this study are respected. Statistica 6 software was used and results were obtained by stepwise forward regression / A produ??o de telha no Estado do Rio Grande do Norte representa cerca de 60 % do total de pe?as cer?micas produzidas. Percebe-se a necessidade de investimento na melhoria da qualidade e da produtividade, promovendo assim inova??es tecnol?gicas. Neste contexto, o objetivo geral deste trabalho ? verificar o efeito da adi??o de caulim, feldspato pot?ssico e quartzo em duas formula??es padr?o, assim como o efeito da temperatura de sinteriza??o nas propriedades tecnol?gicas de retra??o linear de queima, absor??o de ?gua e tens?o de ruptura ? flex?o, atrav?s do ajuste do modelo estat?stico, sendo utilizada a regress?o linear m?ltipla para avaliar a rela??o entre as propriedades tecnol?gicas e as vari?veis independentes. As mat?rias-primas foram caracterizadas atrav?s das seguintes t?cnicas: fluoresc?ncia de raios X (FRX), difra??o de raios X (DRX), an?lise racional (AR), an?lise t?rmica diferencial (DTA) e an?lise granulom?trica (AG). Os corpos-de-prova foram compactados por prensagem uniaxial (25 MPa), e na sequ?ncia secos em estufa a 110 ?C por 24 horas, em seguida sinterizados a 850 ?C, 950 ?C e 1050 ?C, com isoterma de 30 minutos. Os resultadosobtidos indicaram que a adi??o de caulim, em duas formula??es padr?o (M e R) promoveu redu??o nos valores de absor??o de ?gua e aumento nos valores de tens?o de ruptura ? flex?o. As temperaturas de sinteriza??o para o grupo M que proporcionaram os menores valores para a retra??o linear de queima e absor??o de ?gua foram 850 ?C e 950 ?C, respectivamente, e os maiores valores para a tens?o de ruptura ? flex?o foram alcan?ados na temperatura de 950 ?C. No caso do grupo R a temperatura de sinteriza??o que proporcionou os menores valores para absor??o de ?gua e retra??o linear de queima, foi a de 850 ?C, e os maiores valores para a tens?o de ruptura ? flex?o foram atingidosna temperatura de 1050 ?C. Este trabalho descreve a abordagem estat?stica para ajustar o modelo de regress?o linear m?ltipla e apresenta o ajuste do modelo que descreve a rela??o entre as propriedades tecnol?gicas e a porcentagem de caulim, quartzo e feldspato, assim como os modelos que possibilitam a realiza??o de predi??es, desde que n?o sejam ultrapassados os limites inferiores e superiores da porcentagem de argilominerais, fundente e quartzo utilizados neste trabalho. Para isto utilizou-se o software Statistica vers?o 6, obtendo resultados atrav?s da regress?o stepwise forward
23

Aplica??o da ?gua residu?ria das salinas no tratamento de efluente t?xtil

Albuquerque, Liana Filgueira 03 April 2009 (has links)
Made available in DSpace on 2014-12-17T15:01:47Z (GMT). No. of bitstreams: 1 LianaFA.pdf: 3114958 bytes, checksum: 98adbf744d65a1ab7d9d6e74eb3bea83 (MD5) Previous issue date: 2009-04-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The treatment of colored and alkaline effluent has been a challenge to the textile industry. An alternative to remove the colors of those effluents is applying magnesium chloride as a coagulant agent. The magnesium ion, in high pH, hydrolyzes itself, forming the magnesium hydroxide which has a large adsorptive area and positive electrostatic charges able to act as an efficient coagulant. The bittern wastewater from the salt industries has been studied as a potential font of this magnesium ion. Nowadays, this bittern wastewater is evicted into the sea, without any treatment or other use. This thesis has evaluated the potential of applying the wastewater from the salt industries in the treatment of dyeing effluent containing indigo dye and alkaline pH. All the experiments were made in jar tests simulating the chemical coagulation, flocculation and decantation steps ranging the pH and the concentration of magnesium ion. Were obtained removals between 96% and 76% for turbidity, apparent color, and true color, respectively, using 200mg/L Mg2+. The reduction of costs with acid, when were used the salt industries wastewater, comparing with Al2(SO4)3, was 62%. For the degradation of organic matter remaining in the clarified, around 900 mg/L, was applyed the advanced process of oxidation: photo-Fenton. The preliminary results showed 57% reduction in DOC. According to the results obtained, the salt industries wastewater can be applied, as coagulant, in the physical-chemical treatment of the denim dyeing wastewater, so it is not necessary a previous adjust of pH, efficiently and economically / O tratamento de efluentes coloridos e alcalinos tem sido um desafio para as ind?strias t?xteis. Uma alternativa para a remo??o de cor destes efluentes ? a aplica??o do cloreto magn?sio como coagulante. O ?on magn?sio, em pH elevado, se hidrolisa, formando o hidr?xido de magn?sio que possui larga ?rea adsortiva e cargas eletrost?ticas positivas capazes de agir como um eficiente coagulante. Como fonte deste ?on, tem sido estudada a ?gua residu?ria das salinas, conhecida como ?gua-m?e (A-M), rica em diversos sais. Atualmente, ela ? lan?ada diretamente no mar, sem tratamento ou aproveitamento. Esta tese avaliou a capacidade de aplica??o desta ?gua residu?ria no tratamento de efluente de tinturaria contendo corante ?ndigo e pH alcalino. Os experimentos foram realizados em Testes de Jarro, simulando as etapas de coagula??o, flocula??o e decanta??o, variando o pH e a concentra??o do ?on magn?sio. Foram obtidas remo??es m?dias de 96%, 91% e 76% para turbidez, cor aparente e cor verdadeira, respectivamente, utilizando 200 mg/L Mg2+. A redu??o de custos com ?cido, quando se usou A-M em compara??o com o Al2(SO4)3, foi de 62%. Para a degrada??o da mat?ria org?nica remanescente no clarificado, em torno de 900 mg/L, foi aplicado o processo de oxida??o avan?ada: foto-Fenton. Os resultados preliminares apresentaram redu??es de 57% de carbono org?nico dissolvido (COD). De acordo com os resultados obtidos, a ?gua residu?ria das salinas pode ser aplicada, como coagulante, no tratamento f?sico-qu?mico do efluente de tinturaria de denim, sem ajustes pr?vios de pH, de forma eficiente e econ?mica
24

Augusto Matraga: um h?r?i al?m do bem e do mal - uma perpectiva tr?gico-ntol?gica

Leit?o, Eduardo Jos? Pereira de S? 19 December 2006 (has links)
Made available in DSpace on 2014-12-17T15:07:05Z (GMT). No. of bitstreams: 1 EduardoJPSL.pdf: 687770 bytes, checksum: ea9efa61b72d97e3eb90288327c79c87 (MD5) Previous issue date: 2006-12-19 / The present dissertation analyses the philosophy of Friedrich Nietzsche (1844-1900) and the short story written by Jo?o Guimar?es Rosa (1908-1967), A hora e vez de Augusto Matraga (1946) seeking to point out the possibility of the philosophic application of some Nietzschean ideas to enlarge the aesthetic value of the short story. It has been especially aimed at applying the concept of the noble superior being described by Nietzsche, the ubermensch, to the hero s ontological nature, Augusto Matraga. Nietzsche s postulates of the will to power, the elements suggested of the trial between Dionysus and Apollo and the ascetic ideal, will be especially relevant to this work, which intends to establish until what point the hero can be conceived as a good ascetic person, in so far as his noble ontological nature trespass the Christian morality, bringing him closer to the man who, according to Nietzsche, is beyond good and evil. Some Heideggerian concepts will also be relevant in order to reinforce the idea that the judgment created about Matraga is just an appearance that does not contemplate his essential Being, contributing to veil his real tragic-ontological valour, what implies that the aesthetic power of the short has been under valued / O presente trabalho tem como objetivo comparar a filosofia de Friedrich Nietzsche (1844-1900) e o conto de Jo?o Guimar?es Rosa (1908-1967), A hora e vez de Augusto Matraga (1946), no intuito de revelar a possibilidade da aplica??o da filosofia nieztscheana para expandir o valor est?tico do conto e possibilitar a compreens?o do protagonista, Augusto Matraga, como o prot?tipo do ser superior nobre descrito por Nietzsche, o ubermensch. Considerando os conceitos do fil?sofo sobre a vontade de pot?ncia, os elementos dionis?aco e apol?neo, bem como o ideal asc?tico, pretende-se estabelecer at? que ponto o protagonista pode ser concebido como um bom asceta, na medida em que, devido a sua natureza ontol?gica nobre, transgride a moral crist? e se aproxima do conceito do homem que est? al?m do bem e do mal. Al?m da filosofia de Nietzsche, usar-se-? alguns postulados filos?ficos de Martin Heidegger (1889-1976) para refor?ar a id?ia de que o ju?zo criado sobre Matraga ? apenas uma apar?ncia que n?o contempla a ess?ncia do seu Ser, contribuindo para camuflar seu car?ter tr?gico-ontol?gico, o que implica na diminui??o da for?a est?tica do conto
25

Návrh inspekčního sloupu pro kontroly stavu použitého jaderného paliva / Design of equipment of spent nuclear fuel assemblies

Šimek, Ondřej January 2018 (has links)
The diploma thesis aim to the design of equipment for ŠKODA JS a.s., which is part of a new inspection stand (N-SIO). This equipment is an inspection column that provides the possibility to inspect spent fuel assemblies at the operation of the Temelín nuclear power plant. This master thesis is also a summary of the whole design of the new inspection stand and a description of the individual inspection components and devices. One of the parts of the thesis is also a basic strength analysis and a drawing of the main assembly of inspection equipment.
26

Herdeiros de m?rtires: a representa??o do Monaquismo Erem?tico Copta em Atan?sio de Alexandria e Jer?nimo de Estrid?o (S?culos III-IV) / nheritors of martyrs: the representation of Monasticism Coptic hermit in Athanasius of Alexandria and Jerome Stridon (Centuries III-IV)

Oliveira, Jorge Gabriel Rodrigues de 20 April 2016 (has links)
Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-18T10:49:20Z No. of bitstreams: 1 2016 - Jorge Gabriel Rodrigues de Oliveira.pdf: 1803407 bytes, checksum: 14d3e313e5d9cd8d6206d683acccc3ca (MD5) / Made available in DSpace on 2016-10-18T10:49:20Z (GMT). No. of bitstreams: 1 2016 - Jorge Gabriel Rodrigues de Oliveira.pdf: 1803407 bytes, checksum: 14d3e313e5d9cd8d6206d683acccc3ca (MD5) Previous issue date: 2016-04-20 / This research aims to demonstrate the process of developing a martyr stereotype for the hermit Copts monks, through which we believe we can analyze the hagiographic representation drawn to these religious, from textual traces found in primary sources Vita Antonii (357) and Vita Pauli (374-379), written, respectively, by Athanasius of Alexandria (296-373) and Jerome of Stridon (347-420), about the desert monks Anthony the Great (251- 356) and Paul of Thebes (228-330). We understand that the martyrdom of the content is present in this stereotype monastic hermit Copt, introduced by the authors of the sources, this will allow us greater strength in proving our hypothesis about the development of a patristic representation, which aimed to raise the monks as the authentic successors of the martyrs and establishes guidelines and patristic models defined for these religious and those who followed them. / Nesta pesquisa pretende-se demonstrar o processo de elabora??o de um estere?tipo de m?rtir para os monges eremitas coptas, atrav?s do qual acreditamos ser poss?vel analisar a representa??o hagiogr?fica elaborada para esses religiosos, a partir de vest?gios textuais encontrados nas fontes prim?rias Vita Antonii (357) e Vita Pauli (374-379), de autoria, respectivamente, de Atan?sio de Alexandria (296-373) e Jer?nimo de Estrid?o (347-420), acerca dos monges Ant?o do deserto (251-356) e Paulo de Tebas (228-330). Entendemos que se o conte?do do mart?rio estiver presente neste estere?tipo mon?stico erem?tico copta, introduzido pelos autores das fontes, isto nos permitir? maior solidez na comprova??o de nossa hip?tese acerca da elabora??o de uma representa??o patr?stica, que visava al?ar os monges como os aut?nticos sucessores dos m?rtires, al?m de estabelecer diretrizes e modelos patr?sticos definidos para esses religiosos e aqueles que os seguiam.
27

Méthode non destructive de détermination de profils de concentrations en spectroscopie ESCA par distributions angulaires

Pijolat, Michèle 11 July 1979 (has links) (PDF)
Le but de ce travail a été de rechercher les possibilités de la technique ESCA dans la détermination de profils de concentrations sur les cent premiers angströms d'un matériau. La première idée a été d'utiliser la méthode classique de l'abrasion par un bombardement d'ions. Nous avons établi un formalisme permettant d'améliorer la résolution, mais celle-ci reste néanmoins mauvaise à cause des perturbations amenées par l'interaction des ions avec la surface. Cette méthode ne peut cependant pas être écartée car elle donne néanmoins l'allure du profil avec une mauvaise résolution. On a donc cherché une alternative en définissant le principe d'une nouvelle méthode non destructive qui consiste à effectuer une distribution angulaire des électrons analysés. L'extraction du profil passe par une méthode numérique d'optimisation puissante (méthode du Simplexe), mais nécessite d'imposer une contrainte sur la forme du profil, ce qui restreint actuellement le domaine d'applications aux profils monotones (interfaces, diffusions, oxydation, ...). Les études en simulations, puis les applicitions expérimentales (interfaces Ag-Pd, Ag-Al2O3 et SiO2-Si) sont satisfaisantes. Ii est permis de conclure qu'il est possible de déterminer des profils de concentrations par distribution angulaire, à condition d'avoir au préalable bien caractérisé le système à étudier. A cet effet la technique de l'abrasion ionique peut être un moyen d'obtenir la forme du profil en première approximation. Bien que la mise en oeuvre expérimentale de la méthode se soit avérée délicate pour obtenir une mesure fiable et reproductible de rapports d'intensités, et que l'extraction du profil nécessite un temps de calcul d'ordinateur non négligeable, cette nouvelle méthode est capable d'apporter une information de qualité, destinée plutôt d'ailleurs à des études fondamentales qu'à des applications industrielles directes. L'état de la surface de l'échantillon est en effet un critère important de la validité du résultat (nécessité de surfaces peu rugueuses et homogènes, l'analyse n'étant pas ponctuelle), et il convient donc dans la mesure du possible d'utiliser la méthode des distributions angulaires sur des échantillons appropriés pour que la notion de profil fin reste réaliste; l'idéal serait de pouvoir contrôler leur surface par d'autres méthodes, comme la microscopie électronique. De plus, la précision sur la mesure des rapports d'intensités pourrait être améliorée avec un appareillage mieux approprié (spectromètre mobile par exemple). On a vu que les principales limitations observées semblent provenir du fait que l'information sur les concentrations est masquée par l'atténuation exponentielle des électrons; cependant il n'est pas impossible qu'il existe des moyens permettant d'éliminer les solutions aberrantes sans qu'il soit nécessaire d'imposer une contrainte aussi rigide qu'actuellement. Il resterait donc à étendre cette méthode à toutes les formes de profils (notamment dans le but d'étudier le cas particulier intéressant de la ségrégation à la surface d'alliages), et ceci en intervenant surtout au niveau du traitement numérique. D'autre part, il serait intéressant à notre avis de tenter de mettre en oeuvre une autre méthode, à laquelle nous avons déjà fait allusion, basée sur la variation de la profondeur analysée avec l'énergie cinétique des électrons, en utilisant soit plusieurs sources ponctuelles de rayons X, soit le rayonnement synchrotron. Bien que la tentative de Spicer dont nous avons parlé se situe dans des conditions plutôt défavorables, cette dernière reste néanmoins envisageable en utilisant une gamme plus étendue d'énergies excitatrices (de quelques centaines d'eV à quelques KeV).

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