• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 117
  • 14
  • 8
  • 4
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 155
  • 103
  • 79
  • 76
  • 72
  • 54
  • 49
  • 43
  • 34
  • 31
  • 30
  • 21
  • 21
  • 21
  • 19
  • 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

Förändringen av hållbarhetsredovisningens omfattning i årsredovisningar : en kvantitativ studie på svenska börsnoterade bolag.

Ferlin, Malin, Forsström, Louise January 2017 (has links)
Sammanfattning Syfte: Syftet med denna studie är att undersöka om det skett en förändring i mängden redovisning av socialt och miljömässigt ansvarstagande, dvs. hållbarhetsredovisning, i årsredovisningar hos svenska börsnoterade bolag samt undersöka faktorer som kan förklara hållbarhetsredovisning. Metod: Studien har utgått från den positivistiska forskningsfilosofin och använder en deduktiv ansats. För att besvara studiens syfte har en kvantitativ metod använts genom en innehållsanalys samt hypotesprövningar. Populationen består av 142 företag 2012 samt 160 företag 2015 samtliga noterade på Nasdaq OMX Stockholm. Totalt undersöktes 302 årsredovisningar. De data som samlats in är sekundärdata och består av information från årsredovisningar, databaser samt böcker som sedan ställts mot tidigare forskning och teorier. Resultat och slutsats: Studiens resultat visar att det har skett en förändring av socialt och miljömässigt ansvarstagande i företags årsredovisningar. Vårt resultat visar att en positiv förändring av hållbarhetsredovisningen går att utläsa. Dock är denna liten. Studiens statistiska tester visar att det finns ett positivt signifikant samband mellan mängden hållbarhetsredovisning och företags storlek, lönsamhet samt år. Dessutom visar studien att företags bransch har en inverkan på redovisningen men enbart några är signifikanta. Ägarstruktur och kvinnor i styrelsen visar inget signifikant resultat med redovisningen. Uppsatsens bidrag: Studiens praktiska bidrag har kartlagt om det skett en förändring av hållbarhetsrapportering i årsredovisningen hos svenska börsnoterade bolag. Studien påvisar att en positiv förändring har skett mellan 2012 och 2015. Detta kan vara av intresse för de företag som hållbarhetsredovisar. Det teoretiska bidrag denna studie har är att den bidrar med vidare forskning kring variabler som påverkar mängden hållbarhetsredovisning, där lönsamhet och företagsstorlek har en inverkan på hållbarhetsredovisningen. Förslag till fortsatt forskning: Förslag till vidare forskning är att ha ett större spann mellan åren för att tydligare kunna utläsa en förändring. Ytterligare ett förslag är att undersöka rapporteringen på företags separata hållbarhetsrapporter. Till sist ges förslaget om att göra en liknande studie när den nya lagen gällande hållbarhetsredovisning trätt i kraft och blir synlig inom rapporter. / Abstract Aim: The purpose of this study is to examine whether there has been a change in the reporting of social and environmental disclosures, i.e. sustainability reporting, in annual reports of listed swedish corporations and to examine factors that can explain the sustainability report. Method: The study is based on positivist research philosophy and uses a deductive approach. In order to achieve the aim of the study a quantitative method has been used through a content analysis and hypothesis tests. The population consist of 142 companies 2012 and 160 companies 2015, all listed on Nasdaq OMX Stockholm. In total 302 annual reports were examined. The data that has been used are secondary data and the information from annual reports, databases as well as books was then set against previous research and theories. Results and conclusion: The result of the study shows that it has been a change in the reporting of social and environmental reporting in annual reports. Our results indicate that a positive change of sustainability reporting can be seen. However the difference is relatively small. The study’s statistical tests indicate that there is a positive significant correlation between sustainability reporting and company size, profitability and time. In addition the study shows that business sector has an impact on the sustainability reporting but only a few are significant. Ownership structure and women in the board shows no significant results with the sustainability report. Contributions of the thesis: This study's practical contribution is to chart if there has been a change over time of this reporting in the annual reports of swedish listed corporations. The study shows that there has been a change between 2012 and 2015. This result can be of interest for corporations that uses sustaniability reporting. The theoretical contribution of this study is that it contributes with further research on variables that affect the production of sustainability reporting. Where profitability and company size have an impact on this accounting method. Suggestions for further research: Suggestions for future research is to have a wider range between the years in order to be able to read a more accurate difference. Another suggestion is to investigate the reporting on companies separate sustainability reports. A further proposal is to do a similar study when the new law enters into force regarding sustainability reporting and becomes visible within the reports.
22

Avalia??o da potencialidade de argilas de queima clara como mat?rias-primas para o desenvolvimento de novos produtos cer?micos

Sales J?nior, Jos? Carlos Calado 20 August 2008 (has links)
Made available in DSpace on 2014-12-17T14:57:46Z (GMT). No. of bitstreams: 1 JoseCCSJ.pdf: 1343903 bytes, checksum: aa2a5fbffd13b95d16ec1f429e355eb5 (MD5) Previous issue date: 2008-08-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The industries of structural ceramics are among the most important production chains in the state of Rio Grande do Norte. The industry and other interest groups to target the replacement of firewood by natural gas. Studies accordingly concluded that simple change does not guarantee products of superior quality, and that the increase in spending on fuel can economically cripple the use of gas for burning the majority of products manufactured by that action. However some proposals of innovations in terms of process and product are being studied in an attempt to justify the use of natural gas in industry, structural ceramics. One of the aspects investigated is the development of ceramic products differentiated, with new designs and greater value added. Inserted in that context, this paper aims to investigate the potential use of clay-firing clear fabrication of the "bricks of apparent joins drought", a new ceramic product with an innovative way. The development of the work was done in three stages. In the initial stage was held the characterization of raw materials, sought information on physical, chemical, mineralogical and mechanical samples. In the second stage five bodies were made using two of the nine ceramic clay characterized the first step. The masses were analyzed and compared with respect to the size distribution, plasticity and technological properties. In the last part of this work was carried out tests on massive bricks manufactured on an industrial scale. The results show that the nine clays can be used in the manufacture of new ceramic products, is the only constituent of mass ceramic or by mixing with other(s) clay(s / As ind?strias de cer?mica estrutural figuram entre as cadeias produtivas mais importantes do estado do Rio Grande do Norte. O setor e outros grupos de interesse almejam a substitui??o da lenha pelo g?s natural. Estudos realizados nesse sentido conclu?ram que a simples mudan?a n?o garante produtos de qualidade superior, e que o aumento no gasto com combust?vel pode inviabilizar economicamente o uso do g?s para queima da maioria dos produtos fabricados por esse seguimento. Entretanto algumas propostas de inova??es em termos de processo e produto v?m sendo estudadas na tentativa de justificar o uso do g?s natural na ind?stria de cer?mica estrutural. Uma das vertentes pesquisadas ? o desenvolvimento de produtos cer?micos diferenciados, com novos designs e maior valor agregado. Inserido nesse contexto, o presente trabalho tem como objetivo investigar a potencialidade do uso de argilas de queima clara para fabrica??o dos tijolos de junta seca , um novo produto cer?mico com forma inovadora. O desenvolvimento do trabalho foi efetuado em tr?s etapas. Na etapa inicial foi realizada a caracteriza??o das mat?rias-primas, buscando obter informa??es em rela??o ?s propriedades f?sicas, qu?micas, mineral?gicas e mec?nicas das amostras. Na segunda etapa foram formuladas cinco massas cer?micas utilizando duas das nove argilas caracterizadas na primeira etapa. As massas foram analisadas e comparadas em rela??o ? distribui??o granulometria, plasticidade e propriedades tecnol?gicas. Na ?ltima parte desse trabalho foi realizado testes em tijolos maci?os fabricados em escala industrial. Os resultados mostram que as nove argilas podem ser utilizadas na fabrica??o dos novos produtos cer?micos, seja como ?nica constituinte da massa cer?mica ou pela mistura com outra(s) argila(s)
23

Influ?ncia do tratamento superficial e da ciclagem mec?nica na resist?ncia de uni?o ao cisalhamento entre cer?mica feldsp?tica e resina composta fotopolimerizavel

Dondoni, Marilson 16 March 2011 (has links)
Made available in DSpace on 2015-04-14T13:29:52Z (GMT). No. of bitstreams: 1 430600.pdf: 1425866 bytes, checksum: a6284b0edf71e30994f389b10f22f4b4 (MD5) Previous issue date: 2011-03-16 / A cer?mica ? o material restaurador com melhores propriedades est?ticas utilizado na odontologia. Associada a est?tica, outras in?meras propriedades tornam esse material consagrado na odontologia restauradora. Por?m, a cer?mica possui como limita??o um alto potencial de fratura. A substitui??o total de uma restaura??o fraturada muitas vezes ? invi?vel, principalmente quando a pr?tese est? bem adaptada e a fratura n?o ? extensa. Com isso, pode-se lan?ar m?o de reparar a superf?cie da cer?mica fraturada intra-oralmente com resina composta fotopolimeriz?vel. Este estudo teve o objetivo de avaliar a influ?ncia do tratamento superficial e da cilcagem mec?nica na resist?ncia de uni?o ao cisalhamento entre cer?mica feldsp?tica e resina composta fotopolimeriz?vel. Os tratamentos superficiais utilizados foram: asperiza??o com ponta damantada, condicionamento ?cido, jateamento com ?xido de alum?nio e associa??o de jateamento com condicionamento ?cido. Concluiu-se que para um ?ndice de confian?a de 95%, tanto os tratamentos superficiais utilizados, assim como a ciclagem mec?nica, n?o exerceram influ?ncia na resist?ncia de uni?o entre cer?mica feldsp?tica e resina composta fotopolimeriz?vel.
24

Compara??o da resist?ncia de uni?o ? microtra??o de sistemas cer?micos odontol?gicos bilaminares

Fracasso, Lisiane Martins 13 January 2014 (has links)
Made available in DSpace on 2015-04-14T13:30:31Z (GMT). No. of bitstreams: 1 454706.pdf: 713974 bytes, checksum: b4c4d030b32ac428abd2ac68d41fed1c (MD5) Previous issue date: 2014-01-13 / The introduction of ceramics in dentistry occurred since the eighteenth century through the use in complete denture. Bilayered systems composed by metal and ceramic emerged from the 60s and the interest in ceramic systems composed by a ceramic infrastructure that provides resistance associated with an aesthetic cover ceramic becomes evident in the last decades of the past century. Thus, different types of ceramics were inserted in the dental commerce. The aim of this study was to evaluate the microtensile bond strength of three systems of all-ceramics: E- max Press, In-Ceram Zirconia and Mark II with its respectively veneering porcelain. Samples were prepared by using a conformer of ceramic samples and included in the center of a ring of polyvinyl chloride (PVC). Three samples of each system were cut into microbars of a square millimeter in cross section. Five specimens of each sample were randomly selected for the microtensile bon strength test (n = 14). An Universal Testing Machine with 0,5mm/min was used for the microtensile bond strength test. Data were statistically analyzed using the G * Power 3.1.7 software. The distribution of normality was analyzed using the Shapiro-Wilk test (E- max Press, p = 0,96; In-Ceram Zirconia, p = 0,25, Mark II, p = 0,56). There were no homogeneity between samples when was used Levene test (p = 0,01). For this reason, the data were submitted to analysis of variance test followed by multiple comparison Games-Howell test. There was statistically significant difference between groups (p = 0,01), and E-max Press (17,88a ? 5,92 MPa) showed higher resistance to the other groups, followed by Mark II (12,98b ? 4,21 MPa) and In-Ceram Zirconia (9.44c ? 2.25 MPa). Therefore, there is a significant difference between the union of infrastructure and coverage in the different systems, which may influence longevity of these restorations. / A introdu??o das cer?micas na odontologia ocorreu a partir do s?culo XVIII atrav?s da utiliza??o das mesmas em pr?tese total. Sistemas bilaminares compostos por metal e cer?mica surgiram a partir da d?cada de 60 e o interesse por sistemas cer?micos bilaminares compostos por uma cer?mica de infra-estrutura que proporciona resist?ncia associada a uma cer?mica de cobertura que oferece est?tica torna-se evidente nas ?ltimas d?cadas do s?culo passado. Assim, diversos tipos de cer?micas foram introduzidas no mercado odontol?gico. O objetivo deste estudo foi avaliar a resist?ncia ? microtra??o de tr?s sistemas de cer?micas puras: E-max Press, In-Ceram Zirc?nia e Mark II com as respectivas cer?micas de cobertura de cada sistema. As amostras foram confeccionadas atrav?s da utiliza??o de um conformador de amostras de cer?micas e inclu?das no centro de um anel de policloreto de vinila (PVC). Tr?s amostras de cada sistema foram cortadas em palitos de um mil?metro quadrado em sua sec??o transversal. Cinco corpos-de-prova de cada amostra foram selecionados aleatoriamente para o teste de microtra??o (n = 14). Para o ensaio de microtra??o foi utilizada uma M?quina de Ensaio Universal com velocidade de 0,5mm/min. Os dados obtidos foram analisados estatisticamente atrav?s do software G* Power 3.1.7. A distribui??o de normalidade foi verificada com o teste Shapiro-Wilk (E-max Press, p = 0,96; In-Ceram Zirc?nia, p = 0,25; Mark II, p = 0,56). N?o foi verificada homogeneidade entre as amostras atrav?s do teste de Levene (p = 0,01). Portanto, os dados foram submetidos ao teste de An?lise de Vari?ncia seguido de teste de Compara??es M?ltiplas Games-Howell. Foi registrada diferen?a estatisticamente significativa entre os grupos (p = 0,01), sendo que E-max Press (17,88a ? 5,92 MPa) apresentou resist?ncia a microtra??o superior aos demais grupos, seguido de Mark II (12,98b ? 4,21 MPa) e In-Ceram Zirc?nia (9,44c ? 2,25 MPa). Portanto, verifica-se uma diferen?a significativa entre a uni?o das cer?micas de infra-estrutura e cobertura nos diferentes sistemas, o que poder? influenciar na longevidade cl?nica destas restaura??es.
25

Fyra studerandes ideal och resurser på grundutbildningen i psykoterapi / Psychotherapy Trainees About Ideals and Resources During Their Studies

Jarl-Åberg, Cecilia January 2015 (has links)
Den här studien undersöker egna resurser och ideal som fyra studerande på den grundläggande utbildningen i psykoterapi vid Sankt Lukas utbildningsinstitut ger uttryck för. Vidare intresserar sig studien för hur de fyra studerandes uttryckta resurser och ideal överensstämmer med CER-modellen av Skovholt och Rønnestad. CER-modellen beskriver vad som gör en psykoterapeut framgångsrik, en så kallad master therapist. Undersökningsmaterialet består av åtta intervjuer som ingår i ett forskningsprojekt som är ett samarbete mellan Sankt Lukas utbildningsinstitut och Psykologiska institutionen vid Stockholms universitet och som fokuserar på frågan: Vad händer med studenter under en psykoterapi- och psykoterapeututbildning? Materialet har bearbetats enligt en deskriptiv metod och har sedan prövats mot CER-modellens kriterier. Resultatet visar på flera uttryckta ideal och resurser som på ett påtagligt vis överensstämmer med kriterierna i CER-modellen. De ideal som tydligast framträder handlar om viljan att lära, att växa som människa, att bli medveten om den egna personen samt att kunna förhålla sig på ett realistiskt sätt till gränssättningar. Resultatet i denna studie visar på en samstämmighet både med tidigare forskning kring vad som anses vara verksamt i psykoterapi och visar på överensstämmelser med CER-modellen och kan med fördel användas av utbildningsinstitut för att aktivt arbeta med att definiera ideal och sammanhang för sina studerande också i syfte att bjuda in till en kritisk diskussion inom professionsgemenskapen om vad dess ideal rymmer och vad de förbiser. / This paper examines the personal resources and ideals expressed by four students at the basic psychotherapy training at the Sankt Lukas institute. Furthermore, the study deals with the correspondence between the expressed resources and ideals of the four students and the CER model by Skovholt and Rønnestad. The CER model describes what it is that makes a psychotherapist successful, a so-called master therapist. The research material consists of eight interviews that are part of a research project, a collaboration between the Sankt Lukas institute and the Department of psychology at Stockholm University, and focuses on the question: What happens to students during psychotherapy and psychotherapist training? The material has been processed in accordance with a descriptive method and then tested against the criteria of the CER model. The result shows several expressed ideals and resources that correspond substantially with the CER model criteria. The ideals that show up most prominently deal with the desire to learn, to grow as a human being, to become aware of oneself, and to be able to realistically relate to the definition of boundaries. The result in this study indicates a concurrence both with previous research on what is considered to be efficient in psychotherapy and with the CER model, and it may very well be used by educational/training institutes in order to actively promote the defining of ideals and contexts to their students, thus also inviting a critical discussion within the professional community on the content of these ideals and what they may overlook.
26

Caracteriza??o de cer?micas porosas de alumina refor?ada com zirc?nia produzidas pelo m?todo da r?plica

Souza, Fernando Barcelos Marcolino de 29 September 2008 (has links)
Made available in DSpace on 2014-12-17T14:57:49Z (GMT). No. of bitstreams: 1 FernandoBMS.pdf: 3386932 bytes, checksum: 168cdc99a75d4f1724f61a337a6c9569 (MD5) Previous issue date: 2008-09-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Porous ceramics have many applications: thermal insulation, catalytic support, materials to fire protection, filters, and others. There are many techniques to production of ceramic filters. One technique to obtain ceramic filters is the replication method. This method consists in the impregnation of polymeric foam with ceramic slurry followed by a heating treatment that will burn out the organic elements and sintering of the material, resulting of a replication of the original foam. To perform their functions ceramic filters must satisfy mechanical requirements and permeability parameters (darcian k1 and no-darcian k2). The permeability and the strength of the ceramic material are dependent of the pore size and pore distribution. To the use at high temperatures the evaluation of mechanical properties in these temperatures is necessary. In this work the mechanical behavior of two commercial porous ceramics (10 and 40 poros per inch) was studied these materials were submitted to compression and four-point flexure test (room temperature, at 1000 ?C, after thermal shock). Density and porosity measurements, permeability tests and microstructural analysis by scanning electronic microscopy (SEM) were realized. The Results showed that the decrease of mechanical strength of these materials, when submitted to thermal shock, occur for propagation of new cracks from cracks pre-existing and the permeability depends of the pore size / As cer?micas porosas possuem uma vasta gama de aplica??es, tais como: isoladores t?rmicos, suporte catal?tico, materiais para prote??o contra fogo, filtros, dentre outras. Existem v?rias t?cnicas para a produ??o de filtros cer?micos, dentre as quais pode-se destacar o m?todo da r?plica, o qual consiste basicamente na impregna??o de uma esponja polim?rica ou natural com uma barbotina cer?mica, seguindo-se um tratamento t?rmico deste material, onde ocorrer? a decomposi??o do material org?nico e sinteriza??o do material cer?mico, resultando em um corpo cer?mico que consiste em uma r?plica da estrutura da esponja impregnada inicialmente. Al?m de par?metros de permeabilidade (darciana k1 e n?o darciana k2), os filtros cer?micos t?m que atender a requisitos mec?nicos, para que assim possam desempenhar bem as suas fun??es. A resist?ncia mec?nica e a permeabilidade dependem do tamanho e da distribui??o dos poros no material. Para utiliza??o em altas temperaturas, a avalia??o das propriedades mec?nicas a estas temperaturas se faz necess?ria. Neste trabalho foi estudado o comportamento mec?nico de duas cer?micas porosas comerciais (10 e 40 poros por polegada linear) ap?s serem submetidas a ensaios de resist?ncia ? compress?o e ? flex?o em 4 pontos (temperatura ambiente, 1000 ?C e ap?s choque t?rmico). Foram realizadas medidas densidade e porosidade, permeabilidade e an?lise da microestrutura destes materiais por microscopia eletr?nica de varredura. Os resultados mostram que os valores de resist?ncia mec?nica destes materiais s?o dependentes dos defeitos pr?-existentes nos filamentos que comp?em a estrutura do material e a permeabilidade ? fun??o do tamanho dos poros
27

Estudo da formula??o de massas cer?micas provenientes da regi?o do Serid?-RN para fabrica??o de telhas

Andrade, Felipe Lira Formiga 06 March 2009 (has links)
Made available in DSpace on 2014-12-17T14:57:50Z (GMT). No. of bitstreams: 1 FelipeLFA.pdf: 4959653 bytes, checksum: 0da7f126d56ee6a849bfaf9a5d53da1d (MD5) Previous issue date: 2009-03-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This work has for objective study compared the characteristics and technological properties of ceramic bodies from the region of Serid?-RN. The region under study has identified 23 cities where they were 80 ceramics industries. To define the universe of search, there was a survey of pottery that are part of APL Serid? next to the IEL. The characteristics and operating conditions of ceramics industries of the region were identified through a socio-economic questionnaire applied locally, which addressed issues such as: profiles of companies, production process etc. The analysis of information collected from 24 companies identified in seven cities shows that the vast majority of industries is small, with family structure, obsolete equipment and labo, little qualified. Most of the pottery works with low technical knowledge, poor control of the production process and product technology. The raw collected were submitted to analysis of X ray diffraction, chemical composition, termical analysis, particle size distribution and plasticity. Then were produced five formulations and made by uniaxial pressure at 25 MPa for firing in temperatures varying from 850 to 1050 ?C. The firing technological properties evaluated were: mass loss to fire, lineal shrinkage, apparent density, apparent porosity, water absorption and flexural strength (3 points). The results indicated that the raw materials from the region have significant similarities in the composition chemical and mineralogical. Furthermore, it indicates the possibility of the use of cycles of firing faster and efficient than the current, limited to some clay mass burning of certain conditions / Este trabalho teve como objetivo estudar comparativamente as caracter?sticas e propriedades tecnol?gicas de massas cer?micas para telhas da regi?o do Serid?-RN. A Regi?o em estudo possui 23 munic?pios onde foram identificadas 80 ind?strias cer?micas. Para defini??o do universo da pesquisa, fez-se um levantamento das olarias que fazem parte da APL Serid? junto ao IEL do Estado. As caracter?sticas e condi??es de funcionamento das ind?strias cer?micas da regi?o foram identificadas atrav?s de um question?rio s?cio-econ?mico aplicado in loco, que abordava aspectos como: perfil das empresas, processo produtivo etc. A an?lise das informa??es coletadas em 23 empresas identificadas em sete munic?pios permite concluir que a grande maioria das ind?strias ? de pequeno porte, com estrutura familiar, equipamentos obsoletos e m?o-de-obra pouco qualificada. Grande parte das olarias opera com baixo conhecimento t?cnico, prec?rios controles do processo produtivo e tecnol?gico dos produtos. As mat?rias-primas coletadas foram submetidas a ensaios de difra??o de raios X, composi??o qu?mica, an?lise t?rmica, distribui??o de tamanho de part?culas e plasticidade. Em seguida foram produzidas cinco formula??es e confeccionados corpos-de-prova por prensagem uniaxial a 25 MPa para queima variando de 850 ?C a 1050?C. As propriedades tecnol?gicas de queima avaliadas foram: perda de massa ao fogo, retra??o linear, massa espec?fica aparente, porosidade aparente, absor??o de ?gua e carga de ruptura ? flex?o (3 pontos). Os resultados indicaram que as mat?rias-primas provenientes da regi?o apresentam significativas semelhan?as quanto ? composi??o qu?mica e mineral?gica. Al?m disso, indica-se a possibilidade da utiliza??o de ciclos de queima mais r?pidos e eficientes que os atuais, limitando algumas massas argilosas para certas condi??es de queima
28

Estudo das vari?veis de processamento das mat?rias-primas da regi?o do crato - ce na fabrica??o de produtos cer?micos por extrus?o e por prensagem

Santos, Getulio de Moura 10 July 2010 (has links)
Made available in DSpace on 2014-12-17T14:57:55Z (GMT). No. of bitstreams: 1 GetulioMS.pdf: 1235965 bytes, checksum: 2c47ca0471a5470d046cd558e9c9cca4 (MD5) Previous issue date: 2010-07-10 / The limits to inform is about the character stico of basic, quimica, mineralogical and mechaniques of matlaughed material used in the manufacturing process the product certified in economic region the Cariri, specifically in the city of Crato, Cear? state, motivated the development of this work, since in this region the exist ing economic context that a general appear as important in the production chains. Were made twentyfive soils-test specimen collection and the study was performed to differentiate the mat laugh materials of variaveis processing of mathing raw materials in the factory The product mica monkeys by extrusion and pressing. The results were obtained ap s as analyzes: grain size, index of plasticity, fluoresce incidence X-ray difration the X-ray, and analyzes thermicals and properties technological. through s of curves gresifica returned to was a comparison between the retro the linear, absorb to water, porosity and bulk density. the results show that the excellent distribution and character acceptable available for the processing of the structure color dark red. needing, therefore, of the mixture of a less plastic clay with thick granulation, that works as plasticity reducer. In spite of the different resignation forms for prensagem and extrusion, the characteristics of absorption of water and rupture tension the flexing was shown inside of the patterns of ABNT / A limita??o de informa??es sobre as caracter?sticas f?sicas, qu?micas, mineral?gicas e mec?nicas da mat?ria-prima usada no processo de fabrica??o dos produtos cer?micos na regi?o do Cariri, mais precisamente na cidade do Crato, estado do Cear?, motivou o desenvolvimento deste trabalho, visto que nesta regi?o existem cer?micas que num contexto geral figuram como cadeias produtivas importantes no estado. Foram confeccionados vinte e cinco corpos-de-prova da amostra coletada para cada m?todo de conforma??o e foi realizado o estudo das vari?veis de processamento das mat?riasprimas na fabrica??o de produtos cer?micos por extrus?o e prensagem. Os resultados foram obtidos ap?s as an?lises de: granulometria, ?ndice de plasticidade, fluoresc?ncia de raios X, difra??o de raios X, an?lises t?rmicas e propriedades tecnol?gicas. Atrav?s das curvas de gresifica??o obteve-se um comparativo entre a retra??o linear de queima, absor??o de ?gua, porosidade e massa espec?fica aparente. Os resultados mostram que a mat?ria-prima tem excelente distribui??o e caracter?sticas aceit?veis para o processamento de pe?as estruturais de cor escura a vermelha, necessitando, pois, da mistura de uma argila menos pl?stica com granula??o grossa, que funciona como redutor de plasticidade. Apesar das diferentes formas de conforma??o por prensagem e extrus?o, as caracter?sticas de absor??o de ?gua e tens?o de ruptura a flex?o mostrou-se dentro dos padr?es da ABNT
29

An?lise da adi??o de res?duo oriundo do tratamento de esgotos em massa cer?mica utilizada para fabrica??o de telhas

Lima, Andressa Dantas de 30 April 2009 (has links)
Made available in DSpace on 2014-12-17T15:03:20Z (GMT). No. of bitstreams: 1 AndressaDL.pdf: 2033503 bytes, checksum: bb95c834e7758cc771aaa11779a97e45 (MD5) Previous issue date: 2009-04-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Sludge of Wastewater Treatment Plants (WTPs) disposal is a problem for any municipality, for this reason the amount of sludge production is now a key issue in selecting treatment methods. It is necessary to investigate new applications for this waste type, due to the restrictions imposed by the environmental organs. The raw materials used in the Red Ceramic, are generally very heterogeneous, for this reason, such materials can tolerate the presence of different types of wastes. In Rio Grande do Norte, the roof tiles production corresponds to 60,61% from the total of ceramic units produced. Due to the importance of the ceramic industry of roof tiles for the state, allied to the environmental problem of the sludge disposal, this work had for objective to verify the possibility of the incorporation of sewage sludge in ceramic body used for production of roof tiles. In the research, sludge originating from drying beds of WTP of the Central Campus from UFRN and clays originating from a ceramic industry from Goianinha/RN were used. The raw materials were characterized by techniques of: analysis of particles distribution by diffraction to laser; real density; consistence limits; chemical analysis by X-ray fluorescence; mineralogical analysis by X-ray diffraction; organic matter; and solids content. Five batches of roof tiles were manufactured in the approximate dosages of 2%, 4%, 6%, 8% and 10%. To evaluate the properties of each final product, tests of water absorption, impermeability, bending strength, leachability and solubility were accomplished. The roof tiles manufactured with sludge presented characteristics similar to the roof tiles without sludge in relation to the environmental risk. The results showed that it is possible to use approximately up to 4% of sludge in ceramic bodies for production of roof tiles. However, it is observed that the high amount of organic matter (71%) present in the sludge is shown as factor that limits the sludge incorporation in ceramic bodies, worsening the quality of the roof tiles. It is necessary the use of mixtures of different raw materials under point of view of the granulometry and of the other chemical and mineralogical properties for the obtaining of a satisfactory mass to the production of ceramic roof tiles / A disposi??o de lodo de Esta??es de Tratamento de Esgotos (ETEs) ? um problema para qualquer municipalidade, por isso a quantidade de lodo produzido ? hoje um assunto fundamental na sele??o de m?todos de tratamento. Faz-se necess?rio investigar novas aplica??es para esse tipo de res?duo, face ?s restri??es impostas pelos ?rg?os ambientais. As mat?rias-primas utilizadas na Cer?mica Vermelha, em geral, s?o muito heterog?neas, por isso podem tolerar a presen?a de tipos diferentes de res?duos. No Rio Grande do Norte, a produ??o de telhas corresponde a 60,61% do total de pe?as cer?micas produzidas. Dada a import?ncia da ind?stria cer?mica de telhas para o estado, aliada ? problem?tica ambiental da disposi??o de lodo, este trabalho teve por objetivo verificar a possibilidade da incorpora??o de lodo de esgotos em massa cer?mica utilizada para fabrica??o de telhas. Foram utilizados na pesquisa lodo proveniente dos leitos de secagem da ETE do Campus Central da UFRN e argilas provenientes de uma ind?stria cer?mica de Goianinha/RN. As mat?rias-primas foram caracterizadas por t?cnicas de: an?lise de distribui??o de part?culas por difra??o ? laser; densidade real; limites de consist?ncia; an?lise qu?mica por fluoresc?ncia de raios X; an?lise mineral?gica por difra??o de raios X; mat?ria org?nica; e teor de s?lidos. Foram fabricados cinco lotes de telhas nas dosagens aproximadas de 2%, 4%, 6%, 8% e 10%. Para avaliar as propriedades de cada produto final, foram realizados ensaios de absor??o de ?gua, impermeabilidade, carga de ruptura ? flex?o, lixivia??o e solubiliza??o. As telhas fabricadas com lodo apresentaram caracter?sticas semelhantes ?s telhas sem lodo no que diz respeito ao risco ambiental. Os resultados mostraram que ? poss?vel utilizar aproximadamente at? 4% de lodo em massas cer?micas para fabrica??o de telhas. Contudo, observa-se que a elevada quantidade de mat?ria org?nica (71%) presente no lodo mostra-se como fator limitante na incorpora??o de lodo em massas cer?micas, comprometendo a qualidade das telhas. Destaca-se a necessidade de utiliza??o de misturas de diferentes mat?rias-primas do ponto de vista granulom?trico e das outras propriedades qu?micas e mineral?gicas para a obten??o de uma massa satisfat?ria ? produ??o de telhas cer?micas
30

Caractérisation des recombinases XerC et XerD de Proteus mirabilis

Villion, Manuela January 2005 (has links)
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Page generated in 0.0448 seconds