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Machado, Gilmara de Oliveira. "Preparação e caracterização de CMC e CMC graftizada." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-11092001-160555/.
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Polpa celulósica, para obtenção de carboximetilcelulose (CMC), foi obtida a partir do bagaço de cana-de-açúcar através de separação do material em fração fibrosa e medula, sua pré-hidrólise, posterior polpação soda/antraquinona e etanol/água. A polpa soda/antraquinona da fração fibra foi submetida ao processo de branqueamento para obter um material rico em celulose de alta pureza. A polpa branqueada da fração fibra foi utilizada na preparação da CMC na forma de sal de sódio e lítio. Para reações de enxertia foram utilizadas amostras de CMC preparadas no laboratório e comerciais usando isocianatos comerciais e sintetizados. Tanto a CMC como a CMC enxertada foram caracterizadas através de análises térmicas (DSC, TGA), espectroscopia no infravermelho (IV), ressonância magnética nuclear de carbono 13 (RMN 13C) e por microscopia eletrônica de varredura (MEV) e Espectroscopia Dispersiva de Raios-X (EDX). A análise detalhada dos espectros de IV e RMN 13C indica a formação de ligações uretanas em diferentes números de onda e deslocamentos químicos dependendo da CMC e isocianato utilizado. Também observa-se uma pequena mudança na linha de base da curva de DSC indicando uma possível transição vítrea da CMC que diminui após a enxertia da CMC com isocianato. Micrografias de MEV mostraram mudanças estruturais com as reações e a análise através de (EDX) um aumento no teor de carbono e diminuição no de oxigênio com as graftizações. Medidas de condutividade demonstraram que a NaCMC graftizada com isocianato de poli(óxido de propileno) apresenta condutividade de 10-5 S/cm a 100oC, comparável com outros eletrólitos sólidos poliméricosThe cellulosic pulp obtained from sugar cane bagasse was used to synthesize carboxymethylcellulose (CMC), the substrate for the grafting reactions with mono and di-isocyanathes. The sugar cane bagasse was separated into fiber and non-fiber fractions that then were submitted to the pre-hydrolyses and pulping reactions (sodium hydroxide/anthraquinone and ethanol/water). After that the sodium hydroxide/anthraquinone pulp of the fiber fraction was bleached to obtain a high purity cellulosic material. This cellulose was used to obtain the sodium and lithium salts of CMC (NaCMC and LiCMC respectively). Then these samples were used for grafting reactions with commercial octadecylisocyanate and hexamethylene-diisocyanate and synthesized monoisocyanate of poly(propylene oxide). All the samples were characterized through thermal analyses (DSC/TGA), infra-red spectroscopy (IR), solid state 13C nuclear magnetic resonance (13C-NMR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The thermal analysis indicate a possible glass transition of CMC at about 65oC that decreases for to about 29oC after the grafting reaction with isocyanate. The micrographs show structural changes occurred during the several reactions confirmed by thermal analysis. The detailed analysis of IR and NMR 13C spectra of grafted samples indicated the formation of urethane bonds. Conductivity measurements of NaCMC grafted with the poly(propylene oxide) isocyanate gave the value of 10-5 S/cm at 100oC that is comparable with other polymeric solid electrolytes.
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Cleary, Matthew John. "CMC Modelling of Enclosure Fires." University of Sydney. Aerospace, Mechanical and Mechatronic Engineering, 2005. http://hdl.handle.net/2123/696.
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This thesis describes the implementation of the conditional moment closure (CMC) combustion model in a numerical scheme and its application to the modelling of enclosure fires. Prediction of carbon monoxide (CO) in the upper smoke layer of enclosure fires is of primary interest because it is a common cause of death. The CO concentration cannot be easily predicted by empirical means, so a method is needed which models the chemistry of a quenched, turbulent fire plume and subsequent mixing within an enclosed space. CMC is a turbulent combustion model which has been researched for over a decade. It has provided predictions of major and minor species in jet diffusion flames. The extension to enclosure fires is a new application for which the flow is complex and temperatures are well below adiabatic conditions. Advances are made in the numerical implementation of CMC. The governing combustion equations are cast in a conserved, finite volume formulation for which boundary conditions are uniquely defined. Computational efficiency is improved through two criteria which allow the reduction in the size of the computational domain without any loss of accuracy. Modelling results are compared to experimental data for natural gas fires burning under a hood. Comparison is made in the recirculating, post-flame region of the flow where temperatures are low and reactions are quenched. Due to the spatial flux terms contained in the governing equations, CMC is able to model the situation where chemical species are produced in the high temperature fire-plume and then transported to non-reacting regions. Predictions of CO and other species are in reasonable agreement with the experimental data over a range of lean and rich hood-fire conditions. Sensitivity of results to chemistry, temperature and modelling closures is inves- tigated. Species predictions are shown to be quite different for the two detailed chemical mechanisms used. Temperature conditions within the hood effect the for- mation of species in the plume prior to quenching and subsequently species predic- tions in the post-flame region are also effected. Clipped Gaussian and ß-function probability density functions (PDFs) are used for the stochastic mixture fraction. Species predictions in the plume are sensitive to the form of the PDF but in the post-flame region, where the ß-function approaches a Gaussian form, predictions are relatively insensitive. Two models are used for the conditional scalar dissipation: a uniform model, where the conditional quantity is set equal to the unconditional scalar dissipation across all mixture fraction space; and a model which is consistent with the PDF transport equation. In the plume, predictions of minor species are sensitive to the modelling used, but in the recirculating, post-flame region species are not significantly effected.
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Bruno, Laura. "supplier quality management: caso cmc marine." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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Analisi del parco fornitori dell'azienda CMC Marine attraverso l'analisi delle performance, KPI, Vendor Rating e individuazione delle priorità e delle azioni correttive. "Fil Rouge" dell'elaborato la norma UNI EN ISO 9001:2015
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Khamesan, Ahmad. "Synchronous collaborative concept mapping via CMC." Thesis, University of York, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425458.
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Bottone, Francesco. "Les-CMC for diesel engine combustion." Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529364.
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Lee, Kam-fong. "Enhancing students' collaborative learning through CMC discussion." Click to view the E-thesis via HKUTO, 2003. http://sunzi.lib.hku.hk/hkuto/record/B40040057.
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Kwok, Wing-fai Tommy, and 郭榮輝. "Using CMC to enhance students' collaborative learning." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29604734.
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Lee, Kam-fong, and 李錦芳. "Enhancing students' collaborative learning through CMC discussion." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B40040057.
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Bances, Ricardo M., and Norberto J. Chau. "CMC Complejos de cadenas de R-módulos." Pontificia Universidad Católica del Perú, 2012. http://repositorio.pucp.edu.pe/index/handle/123456789/95810.
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Podsedník, Karel. "Biomechanická studie karpometakarpálního (CMC) kloubu palce ruky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230512.
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This master thesis deals with stress-strain analysis of carpometacarpal (CMC) thumb joint. It is a preliminary study, which was not analysed on BUT Mechanical and biomechanical institute yet. There is a comparative stress-strain analysis of CMC with applied total endoprosthesis and physiological condition. The model of geometry was created based on CT images and processed with using software Catia and Solidworks. The problem was solved in numerical FEM (finite element method) in software Ansys 13.0
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Cuschieri, Thomas. "Complete noncompact CMC surfaces in hyperbolic 3-space." Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/3135/.
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In this thesis we study the asymptotic Plateau problem for surfaces with constant mean curvature (CMC) in hyperbolic 3-space H3. We give a new, geometrically transparent proof of the existence of a CMC surface spanning any given Jordan curve on the sphere at infinity of H3, for mean curvature lying in the range (-1,1). Our proof does not require methods from geometric measure theory, and yields an immersed disk as solution. We then study the dependence of the solution surface on the boundary data. We view the set of H-surfaces (CMC surfaces with mean curvature equal to H) as consisting of the conformal H-harmonic maps. We therefore begin by showing smooth dependence on boundary data for H-harmonic maps (with |H| < 1) which solve a Dirichlet problem at infinity. This is achieved by showing that the linearised H-harmonic map operator is invertible as a map between appropriate function spaces. Finally we show smooth dependence on boundary data for H-surfaces which lie in a neighbourhood of the totally umbilic spherical caps {H}. This is achieved by studying the mapping properties of the so-called conformality operator. We use methods from complex geometry to show that the linearisation of this operator at a cap H is an isomorphism for all H ∈ (−1, 1).
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Lindahl, Alexander, and Sanna Malm. "Value Creation Through Synchronous CMC? : The Banks' Perspective." Thesis, Umeå universitet, Företagsekonomi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-92851.
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The development of technology and the Internet have in many ways influenced how companies conduct their business, and what creates a competitive advantage. Previous research have recognized that due to this development, those companies that can create a superior value for the customer will also be the ones that can create a competitive advantage. One industry that has focused a lot on technology during the last couple of years is the banking industry. In fact, this industry was one of the first to adopt and implement technology in their business. The banks have previously used services where there is no physical interaction between customers and employees, such as Internet banking, mobile banking, ATMs etcetera. These services are also known as Self-service technologies (SSTs) and are a well-researched area. Today, there is a new service in the banking industry that has the potential to be “the next big thing” - online advising. This will create a new type of interaction were the customers and employees communicate through the use of a computer software and a computer interface – much like a video exchange. To our knowledge, no bank in Sweden has launched this particular service, which makes the topic very interesting and current to study. In the initial phases of this study, we defined the following research question and purpose that would guide this research: Research Question: How can banks in Sweden use a synchronous CMC service to facilitate value-creation with its customers? Purpose: We aim to understand how a synchronous CMC could facilitate value creation in the banking industry by investigating what types of values online advising could bring about. In addition, by studying similarities between banks, we aim to understand how prepared banks are for the implementation of online advising in terms of opportunities/challenges and if they can use a synchronous CMC to cope with the challenges associated with current SSTs. Online advising relates to the theoretical field of Computer-mediated communications (CMC) where there are no previous studies that answers this research question and purpose. Previous studies within this field have instead focused on other channels of communication, such as email, chat and forums. To fulfil this identified gap, we conducted a study with a qualitative research design and a single case study. After we conducted six semi-structured interviews with a sample that includes the major banks in Sweden we found valuable results. These results indicate that the majority of the banks included are not prepared for a synchronous CMC service - online advising. However, the results showed that this service can facilitate value-creation through saving time and making it more convenient for customers, also known as a cost/sacrifice type of value. Our results further show that a synchronous CMC can cope with the challenge of “isolation”. This means that SSTs can create a human separation that online advising can cope with, as this service creates more of a personal connection between customer and employee.
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Nicoli, Adriana Vietmeier. "Superfícies CMC em variedades tridimensionais : diferencial de Hopf." reponame:Repositório Institucional da UFABC, 2014.
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Orientador: Prof. Dr. Sinuê Dayan Barbero LodoviciDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Matemática, 2014.
O objetivo principal deste texto é apresentar o teorema de Hopf 3.16 nos espaços R3, H3 e S3, resultado clássico sobre superfícies com curvatura média constante (CMC). Antes disto, apresentamos alguns conceitos importantes de Geometria Diferencial, entre eles o Teorema de Gauss-Bonnet 2.13 e o Teorema de Hadamard 2.36. Por fim, de maneira breve, enunciamos o teorema de Hopf em espaços produto (H2XR e S2XR).
The main objective of this paper is to present the Hopf's theorem (3.16) in spaces R3, H3 and S3, a classical result on surfaces with constant mean curvature (CMC). Before this, we present some important concepts of Differential Geometry, including the Gauss- Bonnet Theorem (2.13) and Hadamard's Theorem (2.36). Finally, and briefly, we state the Hopf's theorem in product spaces (H2XR and S2XR).
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Cook, Kathryn. "Learner control and user-interface interactions in CMC courses." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ63620.pdf.
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Franz, Heike. "How computer mediated communication affects information overload in distributed teams." Thesis, Henley Business School, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266546.
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Wilson, Martina E. "Learning and teaching online : structuring computer-mediated communication systems to support interaction at a distance." Thesis, Open University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247054.
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Lee, Ju Young. "The effect of computer-mediated communication (CMC) interaction on L2 vocabulary acquisition a comparison study of CMC interaction and face-to-face interaction /." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1468105.
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Ben, Ramdane Camélia. "Etude et modélisation du comportement mécanique de CMC oxyde/oxyde." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0077/document.
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Les CMC oxyde/oxyde sont de bons candidats pour des applications thermostructurales. Le comportement mécanique et les mécanismes d’endommagement de deux composites alumine/alumine à renforts tissés bi- et tridimensionnels ont été étudiés et comparés. La microstructure de ces CMC à matrice faible a été caractérisée à partir de porosimétrie et de CND, tel que thermographie IR, scan ultrasonore et tomographie X, ce qui a permis de mettre en évidence la présence de défauts initiaux. Le comportement mécanique en traction, ainsi qu’en compression dansle cas du CMC à renfort bidimensionnel, dans la direction des fibres ainsi que dans la direction ±45°, aété étudié à température ambiante. Afin d’exploiter pleinement ces essais, nous avons eu recours à plusieurs méthodes d’extensométrie et de suivi d’endommagement, telles que la thermographie IR et l’émission acoustique. Les propriétés mécaniques à rupture ainsi que le module de Young du CMC à renfort bidimensionnel développé à l’Onera se sont avérées supérieures à celles disponibles dans la littérature. Les mécanismes d’endommagement des matériaux ont été déterminés à partir d’observations post mortem au MEB et d’essais in situ dans un MEB, ce qui a permis d’évaluer la nocivité des défauts initiaux. Enfin, l’étude du comportement mécanique de ces composites a permisde proposer un modèle d’endommagement tridimensionnel qui permettra de poursuivre le développement de ces matériaux grâce à du calcul de structure. A l’issue de cette thèse, des pistes d’amélioration des procédés d’élaboration et de choix d’instrumentation à utiliser pour les futures études, notamment en ce qui concerne le suivi d’endommagement, ont également été proposéesOxide/oxide CMCs are good candidates for thermostructural applications. Themechanical behaviour and damage mechanisms of two alumina/alumina composites with two andthree dimensional woven reinforcements were studied and compared. The microstructure of theseweak matrix CMCs was characterized by porosimetry and NDT methods, such as IR thermography,ultrasound scanning and X-ray tomography, which highlighted initial defects. The mechanicalbehaviour was studied through tensile tests, as well as compression tests in the case of the twodimensionalreinforced CMC. These tests were conducted at room temperature, in the fibres directionsand in the ±45° direction. In order to fully exploit these tests, several extensometry and damagemonitoring methods, such as IR thermography and acoustic emission, were used. Young’s moduli andmaximum stresses and strains of the two-dimensional reinforced CMC developed at Onera appearedto be higher than those available in the literature. The damage mechanisms of the materials weredetermined by post mortem SEM observations and in situ testing in a SEM, which made it possible toassess the nocivity of initial defects. Studying the mechanical behaviour of these composites finallyenabled the development of a three-dimensional damage model that will facilitate the furtherdevelopment of such materials, through finite element analysis. Finally, some improvements regardingthe manufacturing processes and the instrumentation for damage monitoring were suggested forfuture studies
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McHarg, Emma. "Studies in the nature and consequences of Computer-Mediated Ostracism." Thesis, Royal Holloway, University of London, 2012. http://repository.royalholloway.ac.uk/items/a75ee69f-9893-9b86-6b22-6fa1fe305b39/9/.
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Ostracism has been shown to have a variety of negative effects on the target, though the reported nature of these has varied due to differing manipulations of the phenomenon. The experiments reported attempt to characterise the consequences of computer-mediated (CM) ostracism using a range of approaches. Investigation of on-line social behaviour in Internet chat rooms revealed similar patterns of group behaviour, including ostracism, to those reported in face-to-face communication. Fourier analyses revealed periodic structure to the comments made in CM group communication qualitatively similar to that previously reported in dyadic face-to-face communication. Identity changes and ostracism occurrences were also found to be periodic. The power spectra produced by these analyses revealed that comments, identity changes and ostracism typically showed a gradient of 1/f - 11/, a characteristic common to many physical and biological systems but not previously reported in social communication. Further experiments revealed that level of anonymity did not modulate a reduction in comments made by CM ostracised participants. Thus the partial anonymity conferred by CM communication cannot account for the differential effect of ostracism in CM and face-to-face contexts. Experiments on the effect of ostracism upon cognition revealed that ostracised participants reacted significantly slower on a Strop task, but made fewer errors. Performance on a Remote Associates Task was bifurcated whereby those who accurately estimated the extent of their exclusion performed significantly worse than non-ostracised participants. Ostracised participants who under-estimated their exclusion performed similarly to non-ostracised participants. Many of these findings are consistent with a hypothesis that ostracism may be considered a form of (social) pain whose consequences may be mediated by neural substrates that partially overlap with those implicated in responses to physical pain. The findings suggest that a full characterisation of individual and situational differences in ostracism effects may require a combination of techniques, from neuron-imaging to traditional social psychological methodologies.
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Shamsudin, Sarimah. "Computer-mediated communication (CMC) and English for specific purposes (ESP) : an investigation of the use of synchronous CMC to meet the needs of computer science students." Thesis, University of Warwick, 2008. http://wrap.warwick.ac.uk/2586/.
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The purpose of this research was to investigate whether synchronous computer-mediated communication (CMC) would be an effective tool to meet the English for specific purposes (ESP) needs of language learners. A single tertiary education institution in Malaysia was used as the context of the study. A preliminary investigation was conducted to analyze present and target situation needs and lacks of Computer Science students at Universiti Teknologi Malaysia (UTM). Results revealed Computer Science students at UTM need training and practice in the specific communication skills of interviewing and group discussion for systems analysis and design for their current academic needs and future career as CSPs. In order to be successful CSPs the students need to be competent in both face-to-face and electronic forms of communication which include synchronous CMC to elicit information or conduct group discussions such as joint application design (JAD) with their clients. Findings also indicated that Computer Science students and CSPs who graduated from local universities experienced problems articulating orally in English due to speech anxiety, lack of confidence and lack of practice. A set of tasks called CMC ESP tasks were designed and conducted via a synchronous CMC environment to address these needs and lacks. Prior to the Main Study, I conducted two feasibility studies to find out the practicality and suitability of using CMC tools and CMC task types with Computer Science students at UTM. Seventy-two second year Computer Science students participated in the first feasibility study and tested the practicality of using two synchronous CMC tools: 1) NetMeeting for computer-mediated written interaction and 2) Device Duo for computer-mediated oral interaction. Results suggested it was logistically possible to use both synchronous CMC tools but it was more feasible to use Net Meeting because it can simulate real-time text-based discussions and meetings which are common among CSPs. Twenty-seven first year Computer Science students participated in the second feasibility study which confirmed the usability of several CMC ESP task types for investigating the effects of the CMC ESP method on Computer Science students at UTM. I then conducted a longitudinal study. During the main study, an intact group of 32 first year Computer Science undergraduates were subjected to the CMC ESP method (treatment) as part of the activities in their English for Academic Communication (EAC) module. Students were given pre- and post-treatment oral assessment to find out the short term effect of the CMC ESP method on the development of their interviewing and group discussion skills for systems analysis and design. Findings from these assessments were triangulated with the results of pre- and post-treatment self-assessment attitude questionnaires and the analysis of the chat transcripts from the tasks. Results were encouraging. Participants achieved a significant gain in their overall oral performance and in terms of task fulfilment, language and communication ability in the oral assessment.
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Bueso, Ucles Francisco Javier. "Antistaling properties of amylases, wheat gluten and CMC on corn tortilla." [College Station, Tex. : Texas A&M University, 2003. http://hdl.handle.net/1969.1/19.
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Thesis (Ph.D.)--Texas A&M University, 2003."Major Subject: Food Science and Technology" Title from author supplied metadata (record created on Jul. 18, 2005.) Vita. Abstract. Includes bibliographical references.
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Barba, Pacheco Claudia. "Síntesis de carboximetilcelulosa (CMC) a partir de pastas de plantas anuales." Doctoral thesis, Universitat Rovira i Virgili, 2002. http://hdl.handle.net/10803/8503.
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Palabras clave: materiales lignocelulósicos residuales, chopo, pino, paja de trigo, plantas anuales, abacá, sisal, yute, lino, Miscanthus sinensis, bagazo de caña de azúcar, henequén, pastas de cocción rápida sosa/AQ, pastas IRSP, carboximetilcelulosa, comportamiento reológico, grado de sustitución.El presente trabajo describe la preparación y caracterización de muestras de carboximetilcelulosa (CMC) a partir de diferentes materiales lignocelulósicos tanto residuales como no madereros, así como el estudio de la influencia de las condiciones de preparación de la materia de partida y sus características sobre las propiedades finales de las CMCs obtenidas. La producción de carboximetilcelulosa a partir de estos materiales supone una importante contribución ya que, en la mayoría de los casos, el derivado se obtiene a partir de linters de algodón y madera de pino y eucalipto.
Las muestras de CMC fueron preparadas a partir de pastas procedentes de tres diferentes tipos de cocciones:
Pastas blanqueadas de pino, chopo y paja de trigo, provenientes de procesos de cocción con sosa/antraquinona con tiempos de residencia que abarcaban desde los convencionales de aproximadamente 90 min hasta tiempos de cocción rápidos del orden de 3 min.
Pastas blanqueadas de Miscanthus sinensis, bagazo de caña de azúcar y henequén cocidas mediante el método IRSP (Impregnation Rapid Steam Explosion Process)
Pastas papeleras comerciales y blanqueadas provenientes de procesos convencionales sosa/antraquinona de abacá, sisal, yute y lino
La reacción de eterificación se llevó a cabo siguiendo el procedimiento Druvacell a escala laboratorio para la obtención de CMC con alto grado de pureza. Esta se realizó utilizando siempre las mismas condiciones de operación y relación cuantitativa de los materiales presentes.
Los productos purificados fueron caracterizados en función de su grado de sustitución (DS), pureza, solubilidad, viscosidad intrínseca de soluciones de CMC en NaCl 0.1M, peso molecular y comportamiento reológico de soluciones de CMC a diferentes concentraciones. Se encontró que el DS de las CMCs sintetizadas en el laboratorio dependen en gran medida de la morfología del material lignocelulósico del cual provienen. El método usado para la eterificación de las pastas, da como resultado DS cercanos a 1 después de una eterificación y alrededor de 2 si se aplica un segundo tratamiento de eterificación. Con excepción de las CMCs fabricadas a partir de Miscanthus sinensis y bagazo de caña de azúcar, se obtuvieron DS de 0.75 y 1.45 después de una y dos eterificaciones respectivamente.
La pureza de todas las muestras de CMC superaba el 98%. Los valores del peso molecular y el comportamiento reológico de las soluciones de CMC están relacionados con la viscosidad de las pastas de partida. De esta manera, las pastas que tenían un valor menor de viscosidad generaban CMCs con un comportamiento reológico cercano al newtoniano y por el contrario las CMCs que fueron sintetizadas a partir de pastas con mayor viscosidad, presentaban comportamientos pseudoplásticos. Los resultados relacionados con la caracterización reológica de las muestras de CMC, muestran que es posible obtener derivados de celulosa de pastas no madereras con propiedades diferentes a las obtenidas por materiales comunes como la madera o linters de algodón. Estos nuevos materiales presentan un potencial importante para la producción de derivados de celulosa con características innovadoras para aplicaciones industriales específicas, especialmente la estabilidad de la viscosidad con la temperatura
En general, los experimentos realizados mostraron la viabilidad de obtener CMCs similares a las comerciales partiendo de materiales no convencionales. Además, se confirma la posibilidad de producir derivados de celulosa a partir de pastas de cocción rápida y explosión con vapor, ampliándose de esta manera las opciones de estudio de otros derivados de celulosa de interés industrial.
Keywords: waste lignocellulosic materials, poplar, pine, wheat straw, annual plants, abaca, sisal, jute, linen, Miscanthus sinensis, sugar cane, henequen, fast soda/AQ pulps, IRSP pulps, carboxymethylcellulose, rheological behavior, degree of substitution.
In this manuscript we describe the synthesis and characterization of carboxymethylcellulose (CMC) samples from different lignocellulosic residual and non-wood materials. We also describe how the condition of the raw materials affects the preparation and final properties of the CMCs produced. The production of carboxymethylcellulose from these materials is an important contribution because, currently, it is produced from cotton linters and pine and eucalyptus wood.
The CMC samples were prepared from three kinds of cellulose pulps:
Soda/anthraquinone bleached pine, poplar and wheat straw pulps with cooking residence times ranging from 3 to 90 min.
Steam exploded Miscanthus sinensis, sugar cane and henequen pulps cooked by IRSP (Impregnation Rapid Steam Explosion Process).
Commercial bleached paper pulps cooked by the soda/anthraquinone process of abaca, sisal, jute and linen.
High purity carboxymethylcellulose was obtained by the etherification Druvacell process on a laboratory scale, always under the same conditions and with the same chemical amounts.
The final purified products were characterized in terms of their degree of substitution (DS), purity and solubility in concentrated NaOH, CMC intrinsic viscosity in 0.1M NaCl solutions, molecular weight and rheological behavior of CMC samples at different concentrations.
We found that the DS depended on the raw material morphology and properties and not on the cooking temperature of the pulp source. The method we used for the etherification reaction yielded CMCs whose degree of substitution was close to 1 after one etherification reaction, and around 2 when a second etherification reaction was performed at the same conditions. Miscanthus sinensis and sugar cane were the only exceptions because they yielded CMCs with a DS of around 0.75 and 1.45 after one and two etherification treatments.
All CMC samples had purities of over 98%. The molecular weights and the rheological behavior of the CMC solutions were directly related to the viscosity of the pulps. Pulps of lower viscosity therefore produced CMCs whose rheological behavior was similar to Newtonian behavior. On the other hand, the pseudoplastic behavior was obtained from pulps of higher viscosity.
The rheological characterization of the CMC samples shows the viability of obtaining carboxymethylcellulose from non-conventional materials whose characteristics are different from those obtained from common materials such as wood or cotton. These new materials have great potential for producing cellulose derivatives with novel characteristics like temperature stability that make them suitable for specific and tailor-made industrial applications.
Overall, our results show that carboxymethylcelluloses can be obtained from non-conventional materials having similar characteristics to commercial CMC. We also confirm the production of CMC from rapid soda/AQ and IRSP pulps, being posible to extend this study for other cellulose derivatives of industrial interest.
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Zitzen, Michaela. "Topic shift markers in asynchronous and synchronous computer mediated communication (CMC)." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=970670788.
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Triantafyllidis, Antonios. "Large Eddy Simulations of spark ignition processes with the CMC method." Thesis, University of Cambridge, 2009. https://www.repository.cam.ac.uk/handle/1810/252166.
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Tsai, Su-Hsun. "Features of English in CMC and their implications for language learning." Thesis, University College London (University of London), 2001. http://discovery.ucl.ac.uk/10020367/.
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The similarities and differences between written and spoken forms of language have been a focus of interest of many scholars. There is agreement that instead of being a dichotomy or one single continuum, the differences between spoken and written forms can be measured along several dimensions. The coming into existence of computermediated communication (CMC) has made the line of distinction even less obvious. It is technically a writing (key-pressing) behaviour but may be used to carry out spontaneous communication. This study is intended to investigate the special linguistic features of CMC versus non-CMC texts. The study adopts a corpus linguistic approach to analyse a host of 67 linguistic features in synchronous and asynchronous CMC genres and finds interesting differences in the use of these features when used in different temporalities of CMC contexts. A comparison of these features in CMC genres with those in non-CMC texts also reveals some special characteristics of language developed through the use of CMC. The study suggests that, within the general development of CMC, there are emerging genres reflecting particular contexts. As CMC may soon become a major means of communication, and corpus linguistics is an innovative linguistic approach, awareness of CMC is likely to be of increasing importance for language learning. Some pedagogical suggestions are proposed from the experience and findings that have been gained.
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Guillaumat, Laurent. "Microfissuration des CMC : relation avec la microstructure et le comportement mécanique." Bordeaux 1, 1994. http://www.theses.fr/1994BOR10546.
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Les relations entre la microstructure, la microfissuration et le comportement mecanique dans les composites ceramiques ont ete etudiees pour un materiau 2d sic/c/sic. L'analyse en microscopie de l'endommagement de ces materiaux sous sollicitations de traction a revele la presence d'autant de familles de fissures que de constituants, a savoir: une fissuration de la matrice interfil amorcee par les singularites de la macroporosite, puis dans les fils transversaux et enfin dans les fils longitudinaux. Ces trois familles ont une influence selective sur le comportement mecanique. Celui-ci est egalement fortement affecte par les caracteristiques du materiau d'interphase. Les deux premieres familles, en raison de leur propagation importante, diminuent considerablement la rigidite du materiau. Par contre, la localisation de la troisieme famille dans les fils longitudinaux affecte plus particulierement la liaison fibre/matrice. La determination du champ de contraintes par elements finis suivie d'un calcul probabiliste considerant les proprietes mecaniques des constituants du composite et integrant reellement les familles de fissures creees selon les deformations imposees a permis de reconstituer la courbe de comportement de maniere satisfaisante. Enfin, l'analyse d'un composite elementaire constitue d'une seule fibre entouree d'une interphase et d'un depot matriciel d'un double point de vue micromecanique et probabiliste a permis de decrire l'incidence des phenomenes interfaciaux sur les courbes de comportement contraintes-deformations
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Salloum, Caroline, and Emma Jensen. "Ett digitalt engelskklassrum via CMC : Hur påverkar det elevers skriftliga förmåga?" Thesis, Högskolan i Jönköping, Högskolan för lärande och kommunikation, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36362.
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MANCA, BENEDETTO. "DPW potentials for compact symmetric CMC surfaces in the 3-sphere." Doctoral thesis, Università degli Studi di Cagliari, 2019. http://hdl.handle.net/11584/271388.
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Minimal and CMC immersions of a compact surface M in the 3-sphere can be studied via their associated family of flat SL(2, C)-connections on a rank 2 holomorphic vector bundle E over M. However, for surfaces of genus greater than 2 it is a difficult task to describe family of holomorphic flat connections. It is easier to consider a related family of meromorphic flat connections and then reconstruct the associated family of the immersion from it.
The aim of this thesis is to show that it is possible to define a family of meromorphic flat connections on a class of CMC surfaces in S3, from which it is possible to reconstruct the immersion.
We consider CMC surfaces M in the 3-sphere having a group of symmetries which is finite and such that the quotient of the surface by the group is the Riemann sphere.
We show that the surfaces constructed by Lawson in 1970 and by Karcher, Pinkall and Sterling in 1988, belong to this class of surfaces.
We define a holomorphic vector bundle V over the Riemann sphere, equipped with a parabolic structure. We consider a family of logarithmic flat connections on V and we show that such family of logarithmic connections has a prescribed asymptotic.
The main theorem of the thesis shows that the family of logarithmic connections on V can be used to define a DPW potential on the CMC surface satisfying the necessary properties to reconstruct the immersion of the surface M into the 3-sphere via loop group factorisation.
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Abchiche, Bruno. "Augmentation de la limite élastique des composites à matrice céramique : SiC/SiC ou SiC/MAC." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14903/document.
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Les matériaux composites connaissent un large succès. En effet les Composites à Matrice Céramique (CMC) fonctionnant à haute température ont des performances inégalées en termes de fatigue thermomécanique. La durée de vie des CMC est pourtant limitée en raison de l'apparition précoce de fissures matricielles, ouvrant autant de portes à des environnements agressifs, entraînant un abattement prématuré des propriétés mécaniques. Arriver à retarder la fissuration matricielle devient donc une étape clé pour une future importante utilisation des CMC dans l'aéronautique ou l'aérospatial. Les travaux de cette thèse se sont inscrits dans cette logique, où pour protéger les fibres et l'interphase de l'oxydation et de la corrosion, les propriétés de la matrice céramique ont tenté d'être modifiées par l'incorporation de nanofibres en leur sein et par l'émoussement de leurs macropores résiduelsAbstract
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Tranquart, Bastien. "Vers un matériau virtuel pour l’optimisation qualitative d’une nouvelle famille de CMCs." Thesis, Cachan, Ecole normale supérieure, 2012. http://www.theses.fr/2012DENS0014/document.
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Ces travaux portent sur le développement d’un matériau virtuel pour la simulation et l’optimisation des matériaux à microstructure hétérogène, en particulier des composites à matrice céramique de nouvelle génération. Pour ce faire une modélisation du fil est mise en place, au travers d’une démarche intégrée qui prend en compte la complexité de la microstructure et de sa variabilité issues du procédé de fabrication. La démarche proposée repose sur deux étapes : i) la construction d’une morphologie synthétique du fil, basée sur l’étude de micrographies et ii) une méthode de simulation multiéchelle inspirée de la méthode des éléments finis généralisée. L’originalité de cette dernière provient de l’utilisation de motifs, sorte de situations physiques ou topologiques élémentaires, pour décrire à la fois la microstructure et la cinématique locale. La démarche est validée et appliquée à diverses sections de fil synthétiques 2D, pour lesquelles le choix des motifs est discuté. L’extension au traitement de tronçon 3D du fil, ainsi qu’à la simulation de la fissuration à l’aide d’une méthode discrète est discutée et des premiers éléments de réponse sont apportésThe thesis work focus on the development of a virtual material for heterogeneous materials simulation and optimization, especially in the case of now generation of ceramic-matrix composites. To do that, a model at the scale of the yarn is built up, by using an integrated approach that account for the complexity of the microstructure and its variability arising from the manufacturing process. This approach is made of two steps: i) the construction of a synthetic yarn, using micrographics studies and ii) a multiscale approach based on the generalized finites elements method. The originality of that method come from the use of pattern, sort of typical physical or topological situation, that describe both the local structure and kinematic. The approach is validated and applied to various 2D cross-sections of synthetic yarns, for which the choice of patterns is discussed. Extension to 3D section of the yarn, together with the simulation of the fracture in a discrete manner, is discussed and first elements of answer are proposed
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Shahzad, Eram, and Junaid Khan. "Role of Computer Mediated Communication (CMC) in growing trading organization in Pakistan." Thesis, Linnéuniversitetet, Institutionen för datavetenskap, fysik och matematik, DFM, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-18061.
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In third world countries like Pakistan, companies are growing their trading business with remarkable pace. Increase in business volume has raised the challenges to keep growth sustainable. Communication is one of the biggest challenges for most of small size trading and marketing companies in the region. Face-to-face communication is only type of communication available in companies for inter departmental and intra departmental communication. Although face-to-face is one of the best type of communication but it is not possible to have face-to-face communication all the time with all employees especially when volume of company is growing with remarkable pace. In result company faces challenges like information delay, information lost or communication handicap. These challenges affect efficiency and effectiveness of company. We performed qualitative survey with directors and employees of Abuzar Marketing and Trading Company to develop deep understanding with communication problem to eliminate it. Analyzing empirical data and literature, it is found that Computer Mediated Communication (CMC) provides synchronous and asynchronous types of communication, which could help the company to overcome communication challenges with several other potential benefits e.g. knowledge sharing, employees training, democracy in batter manners. Since every company in region is facing similar problem, general recommendation and precautions are made to introduce computer mediated communication (CMC).
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Ding, Lingping. "Using CMC to facilitate English language learning in a Chinese tertiary context." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530839.
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Sze, Pui-shan Carol, and 史佩珊. "Using computer-mediated communication (CMC) to enhance students' participation in group discussion." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29604515.
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Nualas, Florence. "Fonctionnement en oxydation de matériaux composites céramiques (CMC) dans des environnements aéronautiques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00993488.
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Les composites à matrice céramique (CMC) sont destinés à remplacer les superalliages comme constituants de l'architecture des chambres de combustion des moteurs aéronautiques. Dans ces conditions, la durée de vie de ces matériaux diminue fortement du fait de leurs dégradations par oxydation. Pour pallier à ce problème, des CMC à matrice autocicatrisante sont élaborés. Ils possèdent la particularité de s'auto-protéger vis-à-vis de l'oxydation par la formation d'oxyde passivant limitant la diffusion des espèces oxydantes au sein des fissures matricielles. Dans le cadre de ces travaux de thèse, la durabilité d'un composite SiC/[Si-B-C] est évaluée. Son comportement en oxydation/corrosion est alors étudié entre 450 et 1000°C sous air à des pressions partielles d'humidité variables. Une approche multi-échelle (échelle constituants et composite) est envisagée pour comprendre les différents mécanismes mis en jeu lors de la non-cicatrisation/cicatrisation du matériau.
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Cárdenas, Carlos Wilson Rodríguez. "Genericity of bumpy metrics, bifurcation and stability in free boundary CMC hypersurfaces." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-15022019-111803/.
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In this thesis we prove the genericity of the set of metrics on a manifold with boundary M^{n+1}, such that all free boundary constant mean curvature (CMC) embeddings \\varphi: \\Sigma^n \\to M^{n+1}, being \\Sigma a manifold with boundary, are non-degenerate (Bumpy Metrics), (Theorem 2.4.1). We also give sufficient conditions to obtain a free boundary CMC deformation of a CMC inmersion (Theorems 3.2.1 and 3.2.2), and a stability criterion for this type of immersions (Theorem 3.3.3 and Corollary 3.3.5). In addition, given a one-parametric family, {\\varphi _t : \\Sigma \\to M} , of free boundary CMC immersions, we give criteria for the existence of smooth bifurcated branches of free boundary CMC immersions for the family {\\varphi_t}, via the implicit function theorem when the kernel of the Jacobi operator J is non-trivial, (Theorems 4.2.3 and 4.3.2), and we study stability and instability problems for hypersurfaces in this bifurcated branches (Theorems 5.3.1 and 5.3.3).Nesta tese, provamos a genericidade do conjunto de métricas em uma variedade com fronteira M^{n+1}, de modo que todos os mergulhos de curvatura média constante (CMC) e fronteira livre \\varphi : \\Sigma^n \\to M^{n+1}, sendo \\Sigma uma variedade com fronteira, sejam não-degenerados (Métricas Bumpy), (Teorema 2.4.1). Nós também fornecemos condições suficientes para obter uma deformação CMC e fronteira livre de uma imersão CMC (Teoremas 3.2.1 and 3.2.2), e um critério de estabilidade para este tipo de imersões (Teorema 3.3.3 and Corolario 3.3.5). Além disso, dada uma família 1-paramétrica, {\\varphi _t : \\Sigma \\to M} , de imersões de CMC e fronteira livre, damos os critérios para a existência de ramos de bifurcação suaves de imersões CMC e fronteira livre para a familia {\\varphi_t}, por meio de o teorema da função implícita quando o kernel do operador Jacobi J é não-trivial, (Teoremas 4.2.3 and 4.3.2), e estudamos o problema da estabilidade e instabilidade para hipersuperfícies em naqueles ramos de bifurcação (Teoremas 5.3.1 and 5.3.3).
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Bezerra, Kelton Silva. "Um teorema de rigidez para hipersuperfÃcies cmc completas em variedades de Lorentz." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=4823.
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O objetivo deste trabalho à apresentar um teorema de classificaÃÃo para hipersuperfÃcies completas e de curvatura mÃdia constante em variedades de Lorentz de curvatura seccional constante, sob certas limitaÃÃes da curvatura escalar. Para isto usaremos a fÃrmula de Simons, que nos dà uma relaÃÃo entre as transformaÃÃes de Newton Pr e o laplaciano da norma ao quadrado do operador de Weingarten Ã, e um princÃpio do mÃximo devido H. Omori e S. T. Yau. Como primeira aplicaÃÃo obtemos uma classificaÃÃo das hipersuperfÃcies tipo-espaÃo completas e de curvatura mÃdia constante no espaÃo de De Sitter, com curvatura escalar R maior ou igual a 1. ConcluÃmos tambÃm que toda hipersuperfÃcie tipo-espaÃo completa e de curvatura mÃdia constante positiva do espaÃo de Lorentz-Minkowski, com curvatura escalar nÃo-negativa, à um cilindro sobre uma curva plana e, a menos de isometrias, determinamos tal curva.Our aim in this work is to show a classification theorem for complete CMC hipersurfaces in Lorentz manifolds of constant sectional curvature, under certains bounds on the scalar curvature. To this end we use Simons formula, wich gives a relation between Newton transformations and the Laplacian of the squared norm of the Weingarten operator A, as well as a maximum principle due to H. Omori and S. T. Yau. We obtain, as a first application, a classification of complete spacelike CMC hypersurfaces of the De Sitter space, having scalar curvature R maior ou igual a 1. We also conclude that all complete spacelike hypersurfaces with positive constant mean curvature and nonegative scalar curvature in the Lorentz-Minkowski space are cylinders over a plane curve and, up to isometries, we determine this curve.
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Lima, Miriam Bastos Reis Maia. "Perfil do professor mediador: estudo de caso nas licenciaturas no IFAM - CMC." Instituto Federal do Amazonas, 2016. http://repositorio.ifam.edu.br/jspui/handle/4321/51.
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Submitted by Layde Queiroz (layde.queiroz@ifam.edu.br) on 2018-04-19T21:23:16Z
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Perfil do professor mediador estudo de caso nas licenciaturas no ifam cmc.pdf: 4265529 bytes, checksum: 5cda9b9b97f5a53dc4fd10b1a545fa6e (MD5)Made available in DSpace on 2018-04-19T21:23:16Z (GMT). No. of bitstreams: 1 Perfil do professor mediador estudo de caso nas licenciaturas no ifam cmc.pdf: 4265529 bytes, checksum: 5cda9b9b97f5a53dc4fd10b1a545fa6e (MD5) Previous issue date: 2016-07-29
Este estudo objetivou a construção de uma ferramenta que auxilie na identificação do perfil do professor mediador cuja pesquisa está inserida na linha dos Processos Formativos de Professores, os quais tratam da investigação de focos temáticos de ordem estrutural, organizacional, didática e pedagógica referentes aos processos formativos de professores em instituições de ensino tecnológico, considerando assim, os impactos e repercussões decorrentes da organização do trabalho pedagógico do professor que atua nesta modalidade de ensino. Trata-se de uma pesquisa de natureza quanti-qualitativa, a partir de uma abordagem descritiva. A fundamentação teórica aborda a Pedagogia da Mediação, a Experiência de Aprendizagem Mediada (EAM) e o perfil do professor mediador. A pesquisa partiu dos estudos de Vygotsky sobre a zona de desenvolvimento proximal (ZDP), do paradigma de Feuerstein, concernente ao perfil do professor mediador e da proposta didática cognitivo-construtivista, cujo foco foi identificar as competências didáticas que são demandadas do professor, enquanto mediador do processo ensino/aprendizagem. Com estes fundamentos, ao longo do presente estudo, a autora construiu e aplicou um questionário, por meio do qual os professores puderam avaliar a própria práxis. O perfil sócio demográfico dos 36 participantes também fez parte da investigação visando à caracterização dos profissionais, sua formação e prática pedagógica. Os professores participantes trabalham nos Cursos de Graduação em Licenciaturas do Instituto Federal de Educação, Ciência e Tecnologia do Amazonas (IFAM) – Campus Manaus Centro (CMC) localizado na cidade de Manaus, Estado do Amazonas. Como procedimentos metodológicos, realizou-se a análise quantitativa das características do professor mediador, por meio de um conjunto de respostas dadas ao questionário, bem como a análise de conteúdo de três questões subjetivas. O questionário ProfMed foi o produto gerado por este trabalho. Percebeu-se, por parte dos pesquisados, a valorização e empenho na busca da formação continuada, uma vez que o grupo pesquisado apresentou um nível elevado de mediação quanto ao perfil didático: 56% alcançou boa mediação e 44% ótima, o que é compatível com a formação e o tempo de experiência dos professores participantes da pesquisa. No entanto, vale ressaltar que tais resultados não são corroborados pela auto avaliação expressa dos professores, haja vista que houve omissão do parecer sobre seu próprio desempenho por 70% dos participantes. Contudo, através das respostas às perguntas abertas, os professores demonstraram consciência, compromisso e dedicação no desempenho de suas funções.
This study aimed to construct a tool that helps assess the mediator profile. This research is in the line of Formative Processes of Teachers. It deals with research thematic foci of structural, organizational, didactic and pedagogical regarding the formation processes of 56 teachers in technological education institutions, thus considering the impacts and repercussions of the organization of the pedagogical work of the teacher who operates this type of education. It is a quantitative and qualitative research, from a descriptive approach. The theoretical approaches to pedagogy of mediation, the Mediated Learning Experience (MLE) and the mediator profile. The research came from Vygotsky's studies of the Zone of Proximal Development(ZPD), the Feuerstein paradigm concerning the profile of the mediator and cognitive constructivist didactic proposal, whose foci was to identify the educational skills demanded of the teacher as mediator of the teaching / learning process. On these grounds, throughout this study, the author constructed and applied a questionnaire, through which teachers could evaluate their own practice. The demographic profile member of the 36 participants was also part of research to characterize the professionals, their training and teaching practice. Participating teachers work in undergraduate courses in Federal Institute of Education, Science and Technology of Amazonas (IFAM) - Manaus Campus Center (CMC) located in the city of Manaus, state of Amazonas. As methodological procedures, we carried out a quantitative analysis of the facilitator characteristics, through a set of replies to the questionnaire and the analysis of contents of three subjective questions. The ProfMed questionnaire was the product generated by this work. It was noticed, the respondents, appreciation and commitment to the pursuit of continuing education, since the research group presented a high level of mediation as the educational profile: 56% achieved good mediation and 44% good, which is compatible with training and long experience of the teachers participating in the survey. However, it is noteworthy that these results are not expressed by the self-assessment of teachers, given that there was omission of opinion on their performance by 70% of participants. However, through the answers to open questions, teachers demonstrated awareness, commitment and dedication in the performance of their duties.
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Nowacki, Brenna M. "Verification and Calibration of State-of-the-Art CMC Mechanistic Damage Model." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1461761780.
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Trist, Nathan David. "The relationship between trapezium union, CMC joint instability and function following pollicisation." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11941.
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Forty-four pollicisations were assessed radiologically for union and stability of the trapezium as well as for stability of the carpometacarpal (CMC) joint. These parameters were compared with conventional clinical measures for strength, range of motion and function. The union rate of the trapezium was 82%. For those with non-union, the relative risk of trapezial instability was 35.0. Patients with trapezial union demonstrated significantly higher grip strength. For those with union, the relative risk of instability at the CMC joint was 1.4. Those with a stable CMC joint demonstrated significantly higher grip strength and functional results. This study suggests that the aim of obtaining union of the new trapezium is of benefit in the procedure of pollicisation.
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Akayoglu, Sedat. "An Analysis Of Text Based Cmc Of Advanced Efl Learners In Second Life." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614173/index.pdf.
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In the study, it was aimed at determining the discourse patterns of text-based CMC in Second Life in terms of social presence, negotiation of meaning and turn distribution of the students.
During the data collection procedure, 54 freshman students participated in the study. Some reading and writing tasks were carried out in Second Life. During the data analysis, the taxonomy adapted by Akayoglu &Altun (2008) was used for negotiation of meaning and the taxonomy prepared by Rourke, Anderson, Garrison and Archer (2001) was used for social presence. Finally, the words uttered by each student were counted and the equality of turn distribution of the students was measured using Gini Coefficient. At the end of the study, it was found that the most frequently used social presence function was &ldquo
expression of emotions&rdquo
and the least frequently used function was &ldquo
quoting from others&rsquo
messages&rdquo
. In terms of negotiation of meaning functions, the most frequently used function was &ldquo
confirmation&rdquo
and the least frequently used function was &ldquo
reply vocabulary&rdquo
. As for the third research question, the numbers of the words uttered by the students were counted and Gini Coefficient was calculated. At the end of this analysis, it was seen that there was equality in all sessions in terms of turn distribution of the students as it was hypothesized in literature. The findings of this study might be helpful for students, educators and researchers who are willing to attend to and design language courses in Second Life. They might better understand the context.
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Langener, Tobias [Verfasser]. "A Contribution to Transpiraton Cooling for Aerospace Applications Using CMC Walls / Tobias Langener." München : Verlag Dr. Hut, 2011. http://d-nb.info/1015604986/34.
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Siwaborworn, Papakorn [Verfasser], and Andreas [Akademischer Betreuer] Kronenburg. "Conservative LES-CMC modelling for turbulent jet flames / Papakorn Siwaborworn. Betreuer: Andreas Kronenburg." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2014. http://d-nb.info/1047098288/34.
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陳佩璋 and Pui-cheung Esther Chan. "An investigation into the use of CMC in vocational education: a case study." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31256144.
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Yates, Simeon J. "The textuality of computer-mediated communication : speech, writing and genre in CMC discourse." Thesis, Open University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359488.
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Acquarone, Valeria de Matos. "Caracterização reologica de soluções de CMC : viscoelasticidade e influencia de caracteristicas da molecula." [s.n.], 1997. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256460.
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Orientadores: Florencia Cecilia Menegalli, Alfredo de Almeida VitaliDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Foram determinadas as propriedades reológicas em estados estacionário e dinâmico de soluções de amostras comerciais de CMC. As curvas de escoamento de nove amostras (três viscosidades intrínsecas: 6400, 8300, 18600 ml/g e três concentrações em peso: 0,5, 1,0 e 1,5%) foram obtidas em um reômetro de cone e placa a 20°C, fazendo-se três rampas logarítmicas de cisalhamento crescente e decrescente. As soluções mostraram um comportamento pseudoplástico e os parâmetros índice de consistência, k, e índice de comportamento, n, foram calculados. As curvas mostraram uma leve dependência com o tempo. Os dados de viscosidade aparente reduzida, eliminando os efeitos de concentração e peso molecular, foram sobrepostos em uma única curva, e o modelo de Carreau foi ajustado aos dados experimentais. Os espectros mecânicos das nove amostras foram obtidos em ensaios dinâmicos feitos em um reômetro capilar nas temperaturas de 5 a 40°C. As faixas de viscoelasticidade linear foram identificadas em varreduras de deformação. Os dados foram reduzidos à temperatura de referência de 20°C, usando o "método das variáveis reduzidas" e sobrepostos em curvas condensadas. Os espectros não revelaram platôs de elasticidade, indicando que os emaranhamentos são formados e destruídos pela deformação, num fenômeno totalmente físico, e não são devidos a interações químicas mais fortes. A dependência do ponto de emaranhamento com a concentração e o peso molecular é discutida. Foram obtidos espectros típicos de comportamento de soluções diluídas e semi-diluídas e a sobreposição de ?ap(?) e ?'(?) foi possível conforme prevê a regra de Cox-Merz. A viscosidade newtoniana máxima, ?0, mostrou uma dependência do tipo Arrhenius com a temperatura e as "energias de ativação para o escoamento" forma calculadas. O modelo constitutivo de Bird-Carreau foi usado para predizer a viscosidade aparente, ?ap, a viscosidade dinâmica, ?', e a viscosidade elástica dividida pela freqüência, ?"/?. O modelo ajustou bem os dados experimentais de ?ap e ?', mas subestimou os valores de ?"/? a baixas freqüências. A viscosidade intrínseca, [?], foi determinada usando um viscosímetro Cannon-Fenske a 20°C. O coil overlap parameter, c[?], se correlacionou bem com a viscosidade específica ?sp e a transição da região diluída para a semi-diluída se deu a uma concentração crítica c * ¿4/[?], correspondendo a ?sp¿4.
Abstract: The steady and dynamic shear rheological properties of commercial CMC solutions were measured. The flow curves of nine samples (three intrinsic viscosities [?]: 6400, 8300 and 18600 rnl/g and three concentrations by weight: 0,5, 1,0 and 1,5%) were obtained with a cone-plate rheometer at 20°C in three log-ramps increasing and decreasing shearing. All the samples showed power-law flow behaviour with nl (shear-thinning) and the parameters consistency index, k, and flow index, n, were determined. It was observed a slight timedependence. A master curve was plotted for the apparent viscosity and the Carreau model was fitted. The mechanical spectra of the same samples were obtained with a capillary rheometer in the temperature range of 5 to 40°C. The linear viscoelastic ranges were determined in strain sweep tests. Master curves were plotted with both storage and loss moduli at a reference temperature of 20°C using an empirical method, known as the "method of reduced variables". These curves did not show elastic plateaus, indicating that the entanglements formed are based on physical aggregation rather than chemical binding. The dependence of the entanglement point on concentration and molecular weight was discussed. Typical diluted and semi-diluted solution-like mechanical spectra were obtained, with good Cox-Merz superposition of ?ap(?) and ?'(?). The Bird-Carreau constitutive model was used to predict the steady shear viscosity, ?ap, the dynamic viscosity, ?', and the elastic viscosity divided by trequency, ?"/?. The model was able to predict experimental data for ?ap and ?', but ?"/? was not successfully simulated in the low trequency region. The temperature dependence of the zero-shear rate viscosity, ?0, was described as an "Arrhenius dependence" and the "activation energies for flow" were calculated. The transition from dilute to semi-dilute solution behaviour was studied. These experiments were performed at 20°C with a capillary Cannon-Fenske viscometer. The intrinsic viscosities, [?], of the three samples were determined. The coil overlap parameter, c[?], correlated well with the zero-shear rate specific viscosity (?sp). The critical concentration c * was aproximately 4/[?], when ?sp¿4.
Mestrado
Mestre em Engenharia de Alimentos
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Silva, Filho Leonardo Nogueira da. "A presença da grafia da CMC síncrona em textos escolares em língua materna." Pontifícia Universidade Católica de São Paulo, 2008. https://tede2.pucsp.br/handle/handle/13961.
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Previous issue date: 2008-05-16Secretaria da Educação do Estado de São Paulo
This study aims at (1) describing and interpreting the presence of synchronous CMC spelling in school texts produced in Portuguese, taken as the phenomenon on focus; and (2) identifying the representations teachers of Portuguese have about this specific way of communicating. The research topic is justified by the need mother tongue teachers have to position themselves in terms of accepting or rejecting this kind of spelling in texts produced at school. The investigation is theoretically grounded on studies about the written language origin and development (Massini-Cagliari & Cagliari, 1999; Higounet, 2003; Aguiar, 2005); the writing acquisition process (Ferreiro, 2001) and textual production orientations (Brasil, 2001); writing in virtual environments (Rheingold, 1996; Crystal, 2004; Possenti, 2006; Freitag & Fonseca e Silva, 2006); and concepts of representation (Moscovici, 1978, 1995, 2003; Minayo, 1995; Freire & Lessa, 2003). The methodologic approach adopt was the hermeneuticphenomenological one (van Manen, 1990; Freire, 2007). The description and interpretation of the target phenomenon were undertaken through textual registers obtained in interviews and hermeneutic conversations the researcher had with the five Portuguese teachers enrolled in the investigation. The results of this research reveal that the teachers do not allow students to use synchronous CMC spelling in those texts in which the dominant linguistic pattern is required. However, they tend to be more flexible when writing regards informal texts. The research outcomes also provide evidence to claim that text types and facility are the themes that constitute the phenomenon of lived experience focused on in this study
Este trabalho tem por objetivos: (1) descrever e interpretar o fenômeno da presença da grafia da CMC síncrona em textos escolares, e (2) identificar as representações que professores de língua materna têm sobre ele. Essa pesquisa justifica-se pela necessidade de um posicionamento do professor de língua portuguesa em relação ao uso que se faz, atualmente, de uma grafia típica de salas de bate-papo (do tipo MSN) em produções textuais escolares. Fundamentam teoricamente este trabalho, estudos sobre: origem e evolução da escrita (Massini-Cagliari & Cagliari, 1999; Higounet, 2003; Aguiar, 2005); o processo de aquisição da escrita (Ferreiro, 2001) e orientações sobre produção textual (Brasil, 2001); a escrita em ambiente virtual (Rheingold, 1996; Crystal, 2004; Possenti, 2006; Freitag & Fonseca e Silva, 2006); e conceitos de representação (Moscovici, 1978, 1995, 2003; Minayo, 1995; Freire & Lessa, 2003). A abordagem metodológica adotada foi a hermenêuticofenomenológica (van Manen, 1990; Freire, 2007). A descrição e interpretação do fenômeno em foco foi feita por meio de registros textuais, coletados por meio de entrevistas e conversas hermenêuticas, mantidas com os cinco professores de língua portuguesa que participaram da investigação. Os resultados da pesquisa revelam que os professores participantes não permitem o uso da grafia da CMC síncrona em textos escolares que exigem a variante escrita culta; contudo, alguns admitem essa grafia em textos que consideram informais. Os resultados também permitem afirmar que tipos de texto e praticidade são os temas que constituem o fenômeno investigado neste estudo
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Chan, Pui-cheung Esther. "An investigation into the use of CMC in vocational education : a case study /." Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?
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Porcionato, Rodrigo. "Um anel CMC tangente a duas esferas idênticas é uma superfície de Delaunay." reponame:Repositório Institucional da UFABC, 2013.
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GIANCHANDANI, PARDEEP KUMAR. "Joining of Ceramics and Ceramic Matrix Composites (CMC) for Aerospace and Energy Applications." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2711092.
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SiC-based ceramics and composites (SiC, C/SiC & SiC/SiC) are more and more extensively used as advanced materials for aerospace and energy applications. Existing applications are expanding continuously and require advanced materials, design and joining technologies.
The objective of this thesis was to join SiC-based ceramic matrix composites (CMC), ceramics (SiC, Mullite, Alumina) and SiC-based ceramic foams for aerospace and energy applications.
The research was aimed to develop strong, oxidation resistant and high temperature stable joints.
A novel joining technique defined “RM-Wrap” (RM=Mo, Nb, Ta, W Refractory Metals) has been developed within this thesis. The developed technique is a novel brazing technology named RM-Wrap after the metal used as a wrap to contain one or more silicon foils (e.g. Mo-Wrap when a Mo wrap is used to contain a Si foil).
It is a pressure-less joining technology performed at 1450 oC, under an inert environment (Argon flow).
Joining materials are in-situ formed composites made of refractory metals silicides (MoSi2, NbSi2, TaSi2 and WSi2) embedded in a silicon matrix.
RM-Wrap is a highly tailorable joining technique: the quantity of each phase can be modified and more than one refractory metals can be used together. RM-Wrap has been very effective in joining both coated and uncoated CMC, porous and non-porous materials: ceramics (oxide and non-oxide), CMC (SiC-based) and highly porous substrates (SiC foams) having porosity higher than 80% have been soundly joined.
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The joint morphology (interphase and interface) and elemental composition of the joining material was investigated in detail using FESEM and EDS which showed uniform, continuous and crack free joints. XRD investigation confirms the formation of metal silicides. Oxidation resistance of joints was carried out at 1100 oC for 30 minutes (for CMC joints) and 6 hours (for monolithic ceramic joints) in the air; prior and post oxidation examination of joint morphology showed no morphological change and joints remained firmly joined.
Sandwich structures have been developed by Mo-wrap joining two C/SiC as “skins” to the “core” SiC foam. Sandwich structures were tested for thermal shock resistance from RT to 1100 oC in the air for 2 minutes. Three cycles on a single sandwich structure were performed, which remained joined and the joining material composition unchanged.
Joints were mechanically tested in three different modes (i) compression, (ii) tensile and (iii) torsion. Joint strength was higher than the interlaminar shear strength of composites as the fracture was always observed in composites.
In case of monolithic ceramic (SiC) a mixed failure (cohesive and adhesive) was found, which suggest that the joint strength is comparable to ceramic one.
Micro- and nanoindentation tests were also carried out on joining materials.
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Colombo, Simone. "Computer-Mediated Communication as Situated Phenomenon in Massive Multiplayer Online Servers : A Minecraft-based investigation." Thesis, Umeå universitet, Institutionen för psykologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185133.
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The present study investigated Computer-Mediated Communication (CMC) as situated phenomenonin Massive Multiplayer Online (MMO) servers. The popular videogame of Minecraft was chosen as a testbed to examine CMC within its simulated environment. Previous research on videogames explored CMC without considering the role of the server. This research suggests that the onlineserver represents an integral part of the digital environment, in which communication is situated. Data were collected from four servers that shared the same game play mode. A total of 11,658 chatmessages were collected and analyzed with Basic Content Analysis based on word frequencies. Codes were developed and sorted into three predetermined categories: socioemotional positive, socioemotional negative and task area. Results showed that communication significantly differed between almost all servers. Furthermore, it also appeared that in three of the four servers, communication varied between the two weeks of recordings. Future research on CMC is encouraged to consider the role of the online servers. The social construct that may be represented by the MMO servers ought to be explored more thoroughly.I föreliggande studie så undersöks datormedierad kommunikation (CMC) som fenomen baserat iMMO-servrar (Massive Multiplayer Online). Detta utförs genom det populära TV-spelet Minecraft. Tidigare forskning har fokuserat på CMC utan att överväga olika servrar som faktorer. Resultatet av föreliggande studie indikerar att online-servern väsentligen hör ihop med den digitala miljön, där den kontextuella kommunikationen sker. Datainsamling skedde från fyra servrar som har överensstämmande spellägen. Totalt 11 658 chatmeddelanden samlades in samt analyserades genom innehållsanalys vilket baserades på ordfrekvens. Koder utvecklades och sorterades i tre förutbestämda kategorier: socioemotionell positiv, socioemotionell negativ och ”task area”. Resultatet indikerar att kommunikationen skiljde sig signifikant mellan servrar. Dessutom såvarierade kommunikationen mellan de två veckorna av insamlade data på tre av fyra servrar. Framtida forskning rörande CMC bör vidare överväga serverns roll. Därutöver bör det sociala konstrukt som framkommit ur MMO-servrar vidare utforskas.