Dissertations / Theses on the topic 'Expanded graphite'

The aim of this project was to produce expanded graphite (EO) and modified EO-filled electrically conductive polymer composites and to investigate the effects of different additive modifications and preparation conditions on the microstructure and electrical properties of these composites. Modifications included the use of dry blending and ultrasound to reduce their size, use of various suspension media and surfactants to stabilize particle suspensions. To compare the effectiveness of different filler modification processes on electrical conductivity, unmodified and treated EO were incorporated into polypropylene (PP) by melt mixing and EO based dispersions were used to make polyvinyl alcohol (PV A) composites by solution casting. The PP composites were made using various processing methods and conditions at filler concentrations up to 12 wt%, while the polyvinyl alcohol samples contained graphite concentrations up to 8 wt%. To analyse the crystalline morphology of sample and the dispersion of the filler in the composites samples were analysed by light and electron microscopy, DSC and X-ray diffraction. TOA was also used to investigate the thermal stability of the composites. It was found that the presence of graphite, significantly changed the crystal morphology of PP. Solution mixed PVA samples showed improved dispersion and the particle size was effectively reduced.

Polymer composites formed from layered fillers with high surface volume ratio show enhanced reinforcement. Graphite oxide is a high modulus material that can be separated into thin layers with high surface area. The aim of this study is to prepare polymer layered graphite oxide composites using functionalised polyolefin to enhance compatibility with various forms of layered graphite oxide in varying concentration. Functionalised polyolefins reinforced with layered graphite oxides and expanded graphite oxides were prepared using solution blending and melt blending methods. Three different mixing methods with varying shear intensity were employed to prepare polymer layered graphite oxide composites. The crystalline structure, thermal and mechanical properties of the prepared polymer layered graphite oxide composites was studied. Oxidised graphite prepared from the Staudenmaier method and its exfoliated form were dispersed in poly(ethylene-co-methyl acrylate-co-acrylic acid) (EMAA) via solution blending to prepare EMAA layered composites. The thermal stability was determined using thermogravimetric analysis. The EMAA layered composites showed higher thermal stability in comparison with pure EMAA. The mechanical properties of these EMAA layered composites were determined through dynamic mechanical analysis. Shear modulus, yield stress and storage modulus of EMAA in the presence of graphite oxide fillers decreased. A solution blending method was used to prepare poly(propylene-grafted-maleic anhydride) layered expanded graphite oxide composites (PPMA-EGO). Two types of PPMA-EGO were prepared using different mixing methods - low and high shear were employed. The effects of preparative mixing methods on the PPMA-EGO properties were investigated. The mechanical properties of PPMA-EGO obtained from dynamic mechanical analysis indicated that EGO had a reinforcing effect on the elastic behaviour of PPMA-EGO. This is due to strong interfacial adhesion between PPMA and EGO as a result of hydrogen bonding. The elastic behaviour of PPMA-EGO was affected by the surface area of graphite flakes. Low sheared PPMA-EGO elastic behaviour was found to be higher compared with that of high sheared PPMA-EGO. A melt blending method was used to prepare PPMA-EGO with varying EGO concentration. The interconnected network structure of EGO in the PPMA-EGO was not observed as shown by its scanning electron microscopy images. Thermogravimetric analysis of PPMA-EGO indicates increased decomposition temperature of the PPMA matrix. Dynamic mechanical analysis showed enhanced storage modulus of PPMA-EGO. The maximum elastic modulus of PPMA-EGO was observed at 3 %wt of EGO. The electrical conductivity of PPMA-EGO was measured only for EGO concentrations above 2 %wt. The EGO concentration was found to be the most critical factor in the enhancement of the electrical conductivity of PPMA-EGO. Wide angle X-ray diffraction analysis of all polymer layered graphite oxide composites revealed no change in interlayer spacing of graphite layers, indicating the absence of EMAA intercalation in the graphite layers. The crystallisation temperature and crystallinity of all polymer layered graphite oxide composites were determined using differential scanning calorimetry. The results indicated that graphite oxide and expanded graphite oxides acted as nucleating agents in inducing the crystallisation of functionalised polyolefin in the layered composites. However, the degree of crystallinity of functionalised polyolefin decreased in the layered composites.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O grafite natural é uma fonte de baixo custo e é abundante para obtenção de grafeno. O método que se mostrou mais eficiente para a produção de grafeno em larga escala é o método Hummers modificado, que consiste na oxidação do grafite. Com isso, o objetivo principal deste trabalho foi produzir grafeno a partir do grafite natural pelo método de Hummers modificado, além de produzir nanocompósitos de matriz epoxídica reforçada com o grafeno produzido (GP) e o grafeno comercial (GC). Para a produção dos nanocompósitos foi utilizado à resina epoxídica à base de éter diglicidílico do bisfenol A (DGEBA). Foram obtidos nanocompósitos em concentrações de 0,75; 1,00 e 2,00% m/m de GC e GP, com e sem a utilização de solvente THF no processo de preparação. Os resultados obtidos indicaram um alto grau de oxidação do grafite, comprovando assim que o processo foi eficiente. As análises de Raman e FTIR realizadas no GC e GP mostraram que o GP possui as mesmas características do GC. A adição do GC e GP com e sem adição de THF elevou a estabilidade térmica dos nanocompósitos. A alta concentração de nanoreforços e a não utilização de solvente THF em alguns sistemas pode ter contribuído para a formação de aglomerados nestes nanocompósitos, decorrendo assim em uma diminuição do módulo de Young. Através da análise de impedância foi possível verificar que apenas os nanocompósitos com 2%m/m de GP sem THF apresentou percolação dielétrica. Verifica-se que a produção do grafeno a partir do grafite natural possui potencial para aplicação em nanocompósitos estruturais.

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Universidade Federal do Rio Grande do Norte
Epoxy based nanocomposites with 1 wt % and 3 wt % of nanographite were processed by high shear mixing. The nanographite was obtained by chemical (acid intercalation), thermal (microwave expansion) and mechanical (ultrasonic exfoliation) treatments. The mechanical, electrical and thermal behavior of the nanocomposites was determined and evaluated as a function of the percentage of reinforcement. According to the experimental results, the electrical conductivity of epoxy was not altered by the addition of nanographite in the contents evaluated. However, based on the mechanical tests, nanocomposites with addition of 1 wt.% and 3 wt.% of nanographite showed increase in tensile strength of 16,62 % and 3,20 %, respectively, compared to the neat polymer. The smaller increase in mechanical strength of the nanocomposite with 3 wt.% of nanographite was related to the formation of agglomerates. The addition of 1 wt.% and 3 wt.% of nanographite also resulted in a decrease of 6,25 % and 17,60 %, respectively, in the relative density of the material. Thus, the specific strength of the nanocomposites was approximately 33,33 % greater when compared to the neat polymer. The addition of 1 wt.% and 3 wt.% of nanographite in the material increased the mean values of thermal conductivity in 28,33 % and 132,62 %, respectively, combined with a reduction of 26,11 % and 49,80 % in volumetric thermal capacity, respectively. In summary, it has been determined that an addition of nanographite of the order of 1 wt.% and 3 wt.% produced notable elevations in specific strength and thermal conductivity of epoxy
Nanocomp?sitos a base de resina ep?xi e nanografite foram processados por mistura de alto cisalhamento, com concentra??es de 1 % e 3 % p/p de refor?o. O nanografite foi obtido atrav?s de tratamentos: qu?mico (intercala??o ?cida), t?rmico (expans?o por microondas) e mec?nico (esfolia??o por ultrassom). Os comportamentos mec?nico, el?trico e t?rmico dos materiais obtidos foram analisados em fun??o da porcentagem de refor?o. De acordo com os resultados obtidos, n?o foram verificadas altera??es na condutividade el?trica do ep?xi com a adi??o de nanografite, nos percentuais estudados. Entretanto, com base nos ensaios mec?nicos observou-se que os nanocomp?sitos com adi??o de 1 % p/p e 3 % p/p de grafite expandido apresentaram aumento na resist?ncia ? tra??o de 16,62 % e 3,20 % respectivamente, em rela??o ao pol?mero puro. O menor aumento de resist?ncia mec?nica para os nanocomp?sitos com 3 % p/p de nanografite foi relacionado com a forma??o de aglomerados. A adi??o de 1 % p/p e 3% p/p de nanografite tamb?m resultou em uma diminui??o de 6,25 % e 17,60 %, respectivamente, na densidade relativa do pol?mero. Portanto, a eleva??o da resist?ncia espec?fica dos nanocomp?sitos foi de aproximadamente 33,33% para os dois nanocomp?sitos, em rela??o ao pol?mero puro. A adi??o de 1 % p/p e 3 % p/p de nanografite no material aumentou os valores m?dios de condutividade t?rmica em 28,33 % e 132,62 %, respectivamente, combinado com uma redu??o de 26,11 % e 49,80 %, respectivamente, na capacidade t?rmica volum?trica. Em resumo, verificou-se que uma adi??o de nanografite da ordem de 1 % e 3 % p/p produziram eleva??es not?veis na resist?ncia mec?nica espec?fica e condutividade t?rmica do ep?xi

La récupération de chaleur fatale est un véritable challenge pour l’amélioration de l’efficacité énergétique. Le stockage par chaleur latente est une solution qui répond à cet enjeu. Nous nous intéressons aux procédés industriels avec un rapport puissance sur énergie élevé. L’un des procédés identifiés est la stérilisation de produits agroalimentaires. Cependant, les matériaux à changement de phase, peu conducteurs, ne permettent pas d’obtenir des puissances thermiques suffisantes pour ces applications. L’amélioration de la surface d’échange ou l’augmentation de la conductivité thermique du matériau sont alors nécessaires. Un premier dispositif expérimental de stockage thermique comparant différentes techniques d’intensification des transferts a été réalisé. Le concept à base de paraffine et de Graphite Naturel Expansé (GNE) s’est montré le plus performant par rapport à des solutions de type ailettes ou poudre de graphite. La caractérisation thermique du matériau composite GNE/paraffine sélectionné a été réalisée par plusieurs méthodes. Des valeurs de conductivité thermique effective de l’ordre 20 W.m-1.K-1 ont été obtenues. Dans un second temps, un démonstrateur de 100kW/6kW.h est dimensionné et réalisé. Ce dispositif testé sur un procédé de stérilisation existant permet une économie d’énergie de 15%, conforme aux prévisions. L’identification de la conductivité thermique plane du matériau et l’influence de la résistance thermique de contact sont réalisées à l’aide d’un dispositif expérimental, couplé à un modèle numérique. Enfin, le développement d’un dispositif de vieillissement permet l’étude de la stabilité thermique de ce matériau
Waste heat recovery is a challenge for the improvement of energy efficiency. Latent heat storage is a solution that addresses this issue. We focus on industrial processes with high energy on power ratios. One of the identified processes is the sterilization of food products. However, phase change materials, which have low thermal conductivities, do not provide sufficient thermal powers for these applications. The improvement of the heat exchange surface or the increase in thermal conductivity of the material are then necessary. A first experimental thermal storage comparing various heat transfer intensification techniques was achieved. The concept based on paraffin and Expanded Natural Graphite (ENG) has proven to be the most efficient compared to solutions using fins or graphite powder. The thermal characterization of the selected composite material ENG/paraffin was performed by several methods. Effective thermal conductivities values of about 20 W.m-1.K-1 were obtained. In a second step, a 100kW/6kW.h demonstrator is designed and realized. This device tested on an existing sterilization process provides an energy saving of 15%, as expected. The identification of the planar thermal conductivity of the composite material and the influence of the thermal contact resistance are carried out using an experimental device, coupled to a numerical model. Finally, an aging device is used to study the thermal stability of this material

This diploma thesis deals with an issue of lithium-ion batteries, primarily with negative (anode) electrode materials. Natural graphite in two forms, namely flake and expanded graphite, is used in the thesis as active electrode material. It is concerned with study of their capacity and output characteristics depending on the pressing pressure and discharging current. The first part of thesis consists of theory and describes basic principles and the composition of lithium-ion batteries. Materials, their characteristics used in production and theoretical description of measurement techniques are presented then. The second part of the thesis is focused on production, assembling and measurement of the characteristics of the produced electrodes. The aim of the thesis is finding the effects of changes of pressing pressure on the capacity, stability during cycling and stability at higher loads.

[EN] The development of new and more complex polymeric materials involves challenging problems to basic sciences. The relationship between structure and molecular dynamics assumes great importance for the future development of novel technologies based on such polymers. Thus, the understanding of how small changes in the chemical structure affect the properties of the material is essential to progress in the technological and scientific area. An in-depth analysis of the molecular mobility leads to establish the structure-properties relationships. On this basis, the main aim of the present work is to study the molecular mobility of two different families of polymeric materials. For this purpose, the experimental techniques mainly used were Differential Scanning Calorimetry (DSC) and Dielectric Relaxation Spectroscopy (DRS). The first family of polymers characterized was a series of chemically cross-linked copolymers composed by Vinylpyrrolidone (VP) and Butyl Acrylate (BA) monomers. In the first place, the influence of the monomer molar ratio (XVP/YBA) on the copolymer properties was studied. Thus, a Fourier Transform Infrared Spectroscopy (FTIR) analysis verified dipole-dipole interactions between amide groups. The influence of these interactions on several parameters related to the molecular mobility was evidenced by the DSC, DRS and Dynamic Mechanical Analysis (DMA) techniques. Secondly, the effect of the cross-link density on the molecular dynamics of 60VP/40BA copolymers was analyzed using DSC and DRS. One single glass transition was detected by DSC measurements. The DRS analysis showed that an increase of the cross-linking produced a typical effect on the alpha process dynamics. However, the beta process, which possessed typical features of pure JG relaxation, unexpectedly lost the intermolecular character for the highest cross-linker content. The fastest gamma process was relatively unaffected. The second family of polymeric materials studied was a series of segmented polycarbonatediol polyurethane (PUPH) modified with different amounts of expanded graphite (EG) conductive filler. Scanning Electron Microscopy (SEM), X-ray diffraction measurements and FTIR analysis demonstrated a homogeneous dispersion of the EG filler in the matrix. DRS was used to study the dielectric properties of the PUPH/EG composites. The dielectric permittivity of the composites showed an insulator to conductor percolation transition with the increase of the EG content (2030 wt%). The addition of expanded graphite to the matrix caused a dramatic increase in the electrical conductivity of ten orders of magnitude, which is an indication of percolative behavior.
[ES] El desarrollo de nuevos materiales poliméricos de mayor complejidad produce un desafío cada vez mayor en el área de las ciencias básicas. La relación entre la estructura y la dinámica molecular resulta de gran importancia para el desarrollo de nuevas tecnologías basadas en estos materiales poliméricos. Así, una mayor comprensión de cómo pequeños cambios en la estructura química afectan a las propiedades de los materiales resulta esencial para el progreso científico y tecnológico. Un análisis en profundidad de la movilidad molecular permite establecer las relaciones estructura-propiedades. Partiendo de esta base, el principal objetivo del presente trabajo es el estudio de la movilidad molecular de dos familias diferentes de materiales poliméricos. Para ello, las técnicas experimentales utilizadas fueron principalmente la Calorimetría Diferencial de Barrido (DSC) y la Espectroscopia de Relajación Dieléctrica (DRS). La primera familia de polímeros caracterizada fue una serie de copolímeros entrecruzados químicamente compuestos por los monómeros Vinilpirrolidona (VP) y Acrilato de Butilo (BA). En primer lugar, se estudió la influencia de la proporción molar de monómero (XVP/YBA) en las propiedades del copolímero. A través de un análisis por Espectroscopia de Infrarrojo por Transformada de Fourier (FTIR), se verificó la existencia de interacciones dipolo-dipolo entre los grupos amida. Mediante el análisis por DSC, DRS y Análisis Dinamomecánico (DMA), se evidenció la influencia de estas interacciones en diferentes parámetros relacionados con la movilidad molecular. En segundo lugar, se analizó el efecto de la densidad de entrecruzamiento en la dinámica molecular de los copolímeros 60VP/40BA usando DSC y DRS. A través de las medidas de DSC se observó una única transición vítrea para todos los entrecruzamientos. El análisis por DRS mostró como el incremento en entrecruzante produjo el típico efecto en la dinámica del proceso alpha, pero sin embargo, el proceso beta, que tenía las características típicas de una relajación JG, perdió de forma inesperada su carácter intermolecular para el mayor contenido en entrecruzante. El proceso gamma no se vio afectado. La segunda familia de materiales poliméricos estudiada fue una serie de poliuretanos segmentados (PUPH) modificados con diferentes cantidades de grafito expandido (EG), utilizado como relleno conductivo (desde 0 a 50% en peso). El análisis de los resultados obtenidos mediante Microscopía Electrónica de Barrido (SEM), Difracción de Rayos X y FTIR demostró la homogénea dispersión del relleno de EG en la matriz de PUPH. La técnica DRS se usó para estudiar las propiedades dieléctricas de los materiales compuestos PUPH/EG. La permitividad dieléctrica de los materiales mostró una transición de percolación desde aislante a conductor al incrementarse el contenido en EG (rango de 20-30% en peso). La adición de grafito expandido a la matriz de PUPH causó un incremento significativo en la conductividad dieléctrica de diez órdenes de magnitud, lo que indica el comportamiento de percolación.
[CAT] El desenvolupament de nous materials polimèrics de major complexitat produeix un desafiament cada vegada major en l'àrea de les ciències bàsiques. La relació entre l'estructura i la dinàmica molecular resulta de gran importància per al desenrotllament de noves tecnologies basades en aquests materials polimèrics. Així, una major comprensió de com petits canvis en l'estructura química afecten a les propietats dels materials, resulta essencial per al progrés científic i tecnològic. Un anàlisis en profunditat de la mobilitat molecular permet establir les relacions estructura-propietats. Partint d'aquesta base, el principal objectiu del present treball és l'estudi de la mobilitat molecular de dues famílies diferents de materials polimèrics. Per a això, les tècniques experimentals utilitzades van ser principalment la Calorimetria Diferencial de Rastreig (DSC) i l'Espectroscòpia de Relaxació Dielèctrica (DRS). La primera família de polímers caracteritzada va ser una sèrie de copolímers entrecreuats químicament compostos pels monòmers Vinilpirrolidona (VP) i Acrilat de Butilo (BA) . En primer lloc, es va estudiar la influència de la proporció molar de monòmer (XVP/YBA) en les propietats del copolímer. A través d'una anàlisi per Espectroscòpia d'Infraroig per Transformada de Fourier (FTIR), es va verificar l'existència d'interaccions dipol-dipol entre els grups amida. Mitjançant l'anàlisi per DSC, DRS i Anàlisi Dinamomecánico (DMA), es va evidenciar la influència d'aquestes interaccions en diferents paràmetres relacionats amb la mobilitat molecular. En segon lloc, es va analitzar l'efecte de la densitat d'entrecreuament en la dinàmica molecular dels copolímers 60VP/40BA mitjançant DSC i DRS. A través de les mesures de DSC es va observar una única transició vítria per a tots els continguts d'agent entrecreuant . L'anàlisi per DRS va mostrar com l'increment en agent entrecreuant va produir l'efecte esperat en la dinàmica del procés alfa. En canvi, el procés beta, que tenia les característiques típiques d'una relaxació JG, va perdre de forma inesperada el seu caràcter intermolecular per al major contingut en agent entrecreuant. El procés més ràpid gamma no es va veure afectat. La segona família de materials polimèrics estudiada va ser una sèrie de poliuretans segmentats (PUPH) modificats amb diferents quantitats de grafit expandit (EG) , utilitzat com a farcit conductiu (des de 0 a 50% en pes). L'anàlisi dels resultats obtinguts per mitjà de Microscòpia Electrònica de Rastreig (SEM), Difracció de Rajos X i FTIR va mostrar la dispersió homogènia del EG en la matriu de PUPH. La tècnica DRS es va utilitzar per a estudiar les propietats dielèctriques dels materials compostos PUPH/EG. La permitivitat dielèctrica dels materials va mostrar una transició de percolació des d'aïllant a conductor amb l'increment de contingut en EG (20-30% en pes). L'addició d'EG a la matriu de PUPH va causar un increment significatiu en la conductivitat dielèctrica, de deu ordes de magnitud.
Redondo Foj, MB. (2015). A contribution to the study of the molecular mobility in polymeric materials by Thermal and Dielectric Analysis [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59457
TESIS

This thesis deals with lithiation of negative electrode li-ion batteries. In this thesis is used several electrode materials: carbon, FeCl3, lithiated carbon electrodes and silicon carbide. Reduction of irreversible capacity lithium-ion batteries leads to increased capacity and also we can use new materials as a positive electrode. Thesis deals with the differences in the properties of materials using lithiation and their use in practice

This thesis is comprised of a portfolio of musical compositions with accompanying media and a written commentary. In each of the seven compositions, the timbral palettes of musical instruments have been expanded through unconventional physical manipulation. The written commentary presents, in detail, specific examples of how this has been achieved. Alongside descriptions of the work in question, select aspects of other composers' music that approach a similar aesthetic are also referred to. In addition, the fundamental role technology has played in the creation or realisation of certain pieces is addressed. Also included are descriptions of the various customised notational systems used throughout the portfolio. It is outlined how each of these systems has been constructed in a clear and practical manner and, where possible, has incorporated elements derived from the lingua franca in order to communicate the required information as efficiently as possible to the performers.

L’utilisation de l’algèbre pour résoudre des problèmes de graphes a conduit au développement de trois branches : théorie spectrale des graphes, géométrie et combinatoire des groupes et études des invariants de graphes. La notion de graphe d’expansions (invariant de graphes) est relativement récente, elle a été développée afin d’étudier la robustesse des réseaux de télécommunication. Il s’avère que la construction de familles infinies de graphes expanseurs est un problème difficile. Cette thèse traite principalement de la construction de nouvelles familles de tels graphes. Les graphes expanseurs possèdent des nombreuses applications en informatique, notamment dans la construction de certains algorithmes, en théorie de la complexité, sur les marches aléatoires (random walk), etc. En informatique théorique, ils sont utilisés pour construire des familles de codes correcteurs d’erreur. Comme nous l’avons déjà vu les familles d’expanseurs sont difficiles à construire. La plupart des constructions s'appuient sur des techniques algébriques complexes, principalement en utilisant des graphes de Cayley et des produit Zig-Zag. Dans cette thèse, nous présentons une nouvelle méthode de construction de familles infinies d’expanseurs en utilisant les G-graphes. Ceux-ci sont en quelque sorte une généralisation des graphes de Cayley. Plusieurs nouvelles familles infinies d’expanseurs sont construites, notamment la première famille d’expanseurs irréguliers
Applying algebraic and combinatorics techniques to solve graph problems leads to the birthof algebraic and combinatorial graph theory. This thesis deals mainly with a crossroads questbetween the two theories, that is, the problem of constructing infinite families of expandergraphs.From a combinatorial point of view, expander graphs are sparse graphs that have strongconnectivity properties. Expanders constructions have found extensive applications in bothpure and applied mathematics. Although expanders exist in great abundance, yet their explicitconstructions, which are very desirable for applications, are in general a hard task. Mostconstructions use deep algebraic and combinatorial approaches. Following the huge amountof research published in this direction, mainly through Cayley graphs and the Zig-Zagproduct, we choose to investigate this problem from a new perspective; namely by usingG-graphs theory and spectral hypergraph theory as well as some other techniques. G-graphsare like Cayley graphs defined from groups, but they correspond to an alternative construction.The reason that stands behind our choice is first a notable identifiable link between thesetwo classes of graphs that we prove. This relation is employed significantly to get many newresults. Another reason is the general form of G-graphs, that gives us the intuition that theymust have in many cases such as the relatively high connectivity property.The adopted methodology in this thesis leads to the identification of various approaches forconstructing an infinite family of expander graphs. The effectiveness of our techniques isillustrated by presenting new infinite expander families of Cayley and G-graphs on certaingroups. Also, since expanders stand in no single stem of graph theory, this brings us toinvestigate several closely related threads from a new angle. For instance, we obtain newresults concerning the computation of spectra of certain Cayley and G-graphs, and theconstruction of several new infinite classes of integral and Hamiltonian Cayley graphs

This thesis deals with the replacement of the lid gasket of the primary collector of the steam generator VVER 1000. Original sealing by nickel rings is replaced by kammprofile gasket with expanded graphite layers. The thesis compare the properties of both types of gaskets and the new and the original configuration of flange joint which have been calculated according to EN 1591. The results are compared and conclusions arising therefrom are presented. The work includes results of FEM analysis of the new configuration of the flange joint. There is also a description of the main components of the nuclear power plants VVER 1000 primary circuit in the introductory part which focused on the construction and operation of the steam generator and its primary collector.

Presented work investigates the problem of secondary lithium-ion cells and the different available cathode materials. We have prepared samples of LiFePO4 with the addition of different kinds of carbon materials such as Super P, Vulcan and expanded graphite. We have always created the sample with and without surfactant. Developed samples were compared by measuring electrochemical methods (cyclic voltammetry, charge and discharge cycles and impedance spectroscopy). We also modeled the three-point cell for measuring electrochemical electrode materials.

This is a study about how I produced a graphic novel to introduce a model of the self that is informed by complexity theory to an audience of comic book and graphic novel enthusiasts. Because this model of the self has the potential to preserve, extend, and/or reinforce character strengths that are operationalized as virtuous behavior, and that also function as inner resources in times of adversity, my study explores storytelling by sequential art as a communication method that some counselors and educators might use to counsel and educate large segments of popular culture. Also, more generally, I explore the possibility that productions combining entertainment and preventive information might have commercial value on their own and also improve wellbeing and increase embodied social capital without the need of traditional institutional funding. Under the theoretical frameworks of Complexity Theory and Poetic Logic, I combined Active Imagination, Narrative, Writing, Poetic, and Arts-based methods of inquiry, to research the literary and artistic forms by which I could create a compelling mythopoeic story to indirectly educate about the potential of the self. The results of this investigation show that the production of an instrument aiming at these goals can be completed, however, future studies are needed to assess the effectiveness of this production as a prevention tool and as a commercially viable product in the entertainment marketplace. While the results of this investigation are not generalizable, they may inspire other counselors and educators to communicate with larger audiences their expert knowledge of human nature as a form of preventive public counseling.

This diploma thesis is engaged in replacement of gasket ion filter used in the ion filter of continuous cleaning TC SV01 of rector coolant in nuclear power plants with VVER 440 reactor. Original nickel gasket is replaced by kammprofile gasket with expanded graphite. Calculation results are compared with each other and are described as suggestions for further calculation. The first part included a detailed description of the primary coolant water chemistry, along with a description of the function and structure of ion filter.

This diploma work is engaged in replacement of gasket main dividing plane of reactor coolant pumps in nuclear power plant Paks. Of the newly suggested gasket is kammprofile gasket with expanded graphite layer. This work contain suggestion and calculation of new sealing a knot and calculation existing sealing the knot. Results are confrontacion and sequentially is discussed influence on main dividing plane HCČ 317 by use the new and the existing gasket. In this work is contained description brief of legislation. This legislation must keep by design components dedicated for nuclear equipment. Next this work contain view of the most important sealing knots used in primary system of Nuclear Power Plant type VVER 440.

Ma thèse se situe à l'intersection de \textit {la théorie des groupes géométrique} et \textit{la théorie des groupes mesurée}. Une question majeure dans la théorie des groupes géométrique est d'étudier la classe de quasi-isométrie (QI) et la classe d'équivalence mesurée (ME) d'un groupe, respectivement. $L^p$-équivalence mesurée est une relation d'équivalence qui est définie en ajoutant des contraintes géométriques avec d'équivalence mesurée. En plus, QI est une condition géométrique. Il est une question naturelle, si deux groupes sont QI et ME, si elles sont $L^p$-ME pour certains $p>0$. Dans mon premier article, en collaboration avec R. Tessera, nous répondons négativement à cette question pour $p\geq 1$, montrant que l'extension centrale canonique d'un groupe surface de genre plus élevé ne sont pas $L^1$-ME pour le produit direct de ce groupe de surface avec $\mathbb{Z}$ (alors qu'ils sont à la fois quasi-isométrique et équivalente mesurée).Dans mon deuxième papier, j'ai observé un lien général entre la géométrie des expandeurs, defini comme une séquence des quotients finis ( l'espace de boîte) d'un groupe finiment engendré, et les propriétés mesurée theorique du groupe. Plus précisément, je l'ai prouvé que si deux <> sont quasi-isométrique, les groupes correspondants doivent être <>, une notion qui combine à la fois QI et ME. Je prouve aussi une version de ce résultat pour le plongement grossière, ce qui permet de distinguer plusieurs classe des expandeurs. Par exemple, je montre que les expandeurs associé à $SL(m, \mathbb{Z})$ ne grossièrement plongent à les expandeurs associés à $SL_n(\mathbb{Z})$ si $m>n$
My thesis lies at the intersection of \textit{geometric group theory} and \textit{measured group theory}. A major question in geometric group theory is to study the quasi-isometry (QI) class and the measure equivalence (ME) class of a group, respectively. $L^p$-measure equivalence is an equivalence relation which is defined by adding some geometric constraints with measure equivalence. Besides, quasi-isometry is a geometric condition. It is a natural question if two groups are QI and ME, whether they are $L^p$-ME for some $p>0$. In my first paper, together with R. Tessera, we answer this question negatively for $p\geq 1$, showing that the canonical central extension of a surface group of higher genus is not $L^1$-ME to the direct product of this surface group with $\mathbb{Z}$ (while they are both quasi-isometric and measure equivalent). In my second paper, I observed a general link between the geometry of expanders arising as a sequence of finite quotients (box space) of a finitely generated group, and the measured theoretic properties of the group. More precisely, I proved that if two box spaces' are quasi-isometric, then the corresponding groups must be `uniformly measure equivalent', a notion that combines both quasi-isometry and measure equivalence. I also prove a version of this result for coarse embedding, allowing to distinguish many classes of expanders. For instance, I show that the expanders associated to $SL(m,\mathbb{Z})$ do not coarsely embed inside the expanders associated to $SL_n(\mathbb{Z}$ if $m>n$

碩士
國立中興大學
物理學系所
103
In general liquid-phase-exfoliation(LPE) process, the graphite intercalation compounds(GICs) can expand the interspace between the graphite layers and separate graphite into graphene flakes with high intensity sonication. In our research, we use a process combine LPE process and electrochemical expansion to exfoliate graphite into few-layer graphene flakes(FLG) with higher yields quickly, and we use spin-coating to put few layer graphene on the substrate. The morphology and thickness of few layer graphene can be investigated by scanning electron microscope(SEM) and atomic force microscope(AFM). The lattice structure can be identified by X-ray diffraction and selected area diffraction of transmission electron microscope(TEM). The composition can be measured by Raman spectrum and X-ray photoelectron spectroscopy(XPS). Finally, we use conductive AFM to measure the electrical properties of graphene flakes. And the results show the good quality of graphene flakes which are 5 ~ 10 layers can be applied on electronic devices.

碩士
環球科技大學
生物技術研究所
103
In this study, a Ball milling and Incipient Wetness Impregnation( IWI) preparation of boron-containing expanded graphite (BEG) and nickel (boron) expanded graphite (NiBEG), can expect boron (Ni) was impregnated to expanded graphite (EG) in. Can be learned from the research results, each holding temperature expandable graphite different time, the best conditions are holding temperature for one hour of EG-1h, so the subsequent experiments with this EG as a precursor experiment. Preparation of the boron-containing expanded graphite into incipient wetness method and ball milling, synthesis and distinguish two-step synthesis and step synthesis. Experimental results show that boron and a boron difference is, the boron-containing expanded graphite (BEG) to increase heat resistance, and is displayed in the XRD impregnated with boron to make more lattice signal becomes stronger, while milling Law two-step synthesis (BEG-BT) of the strongest signals, so the subsequent preparation of nickel condition that is expandable graphite holding temperature for one hour, and ball milling method and two-step synthesis prepared a nickel (boron) expanded graphite (NiBEG-BT and NiEG-BT). Eventually expanded graphite boron is to prepare boron diamond explosion method. Expectations to do using boron diamond electrode material biological sensors.

碩士
義守大學
材料科學與工程學系
104
In this paper, we report a facial method for fabricating stable conductive superhydrophobic films from expanded graphite (EG)/carbon nanotube (CNT)/polymer composites. This method possesses the advantages of being both simple and inexpensive as well as utilizing non-fluorine-containing compounds. The as-prepared EG/CNT/polymer composites exhibit a good superhydrophobicity with a high water contact angle (162o). A sliding angel of 6o for a 6 L droplet indicates excellent non-sticking behavior. Furthermore, the superhydrophobic EG/CNT/polymer composites had excellent environmental stability with regard to both heating and organic solvent treatment in terms of the contact angle to water. Such superhydrophobic coatings have potential applications in microfluidic devices, liquid transportation, and nonwetting surfaces.

碩士
國立臺灣師範大學
化學系
105
Aluminum is not only the most abundant metal on Earth, but also safe to deal with in comparison to other kind of metal-ion battery. It contains the transfer of three electrons in redox reaction of aluminum. Furthermore, the density of aluminum is around four times larger than the one of lithium, indicating that under the same volume, aluminum provides almost four times greater volumetric capacity than lithium. In our previous study, we found that the aluminum-ion batteries with natural flake graphite as cathode material contains high capacity and high stability. In this work, we investigate the cathodic performance of expanded graphite with natural flake graphite as the precursor. We discovered that under a high current density of 1000 mA/g, the battery also contains high capacity and high stability.Moreover, the galvanostatic curves and the cyclic voltammogram of this work are the same as the previous one.From in-situ XRD and in-situ raman spectroscopy, it shows the intercalation/deintercalation of AlCl4- ions into/out of to expanded graphite. The SEM image also reveal the structural difference of expanded graphite between before and after charging-discharging.

It is unclear whether all intercalation techniques truly lead to the insertion of atoms between the graphite layers, or also lead to other effects which contribute to expansion. The objective of this project is to better understand the effects caused by different intercalation methods. Three intercalation methods were explored to determine the method which incurs the least damage to the surface and microstructure of the graphite intercalated compounds, yet achieves the best intercalation and therefore expansion. All the main findings are summarised below:  The gas phase sample had virtually no mass loss at the point where expansion took place. Therefore the intercalation was very efficient, producing large expansion without significant mass loss.  The mass loss that only occurs at the sublimation of iron chloride (320 ºC) indicates the excessive "un-intercalated" or residual iron chloride.  After oxidation, before purification, the gas phase sample has 25 % residual mass; this also proves the presence of impurities and residual iron chloride in the exfoliated sample. For the Hummers and electrochemical samples, expansion and mass loss occur over a wide temperature range, this indicates that graphite oxide was formed rather than the theoretically expected "insertion of atoms between the sheets".  The mass losses before 200 ˚C of the samples of the Hummers and electrochemical methods are more evidence that graphite oxide and graphite surface complexes with oxygen were produced.  The Hummers and electrochemical intercalation methods show similar expansion and mass loss curves, therefore it can be concluded that the reaction mechanism for both these methods is alike.  The gas phase method yields the best expansion of 250 % using the TMA, whereas both the other methods deliver approximately 220 %.  Using microwave expansion the electrochemical intercalation method yields the best bulk volume expansion of 1500 %, with the gas phase sample delivering a volume expansion of 1450 %. The Hummers samples are extremely damaged. This is clear from the several and deep oxidation pits visible throughout the basal plane of these samples. The basal plane and the edges are even eroded before purification and oxidation. This intercalation technique employs oxidisers in the preparation method which additionally oxidises the samples. This explains why the Hummers method renders the most damage. The residual material on the gas phase sample acts as catalysts making the sample very reactive and consequently damaging the surface during oxidation. The partially oxidised purified gas phase sample visibly shows the pits and roughened edges. There are two “types” of intercalation. The first intercalation “type” is the actual insertion of atoms or molecules between the graphite layers, whereas the other “type” of intercalation is the production of graphite oxide. The compound comprises carbon, oxygen and hydrogen, obtained by treating graphite with strong oxidisers. The functional groups usually found in graphite oxide are carbonyl (C=O), hydroxyl (-OH), phenol amongst others and also some impurities of sulphur when sulphuric acid is used. Both these intercalation types lead to expansion. It is recommended that a more efficient method for removal of residual material in the gas phase samples be explored. It is also recommended that more research be done to determine the reaction mechanisms during the three different intercalation methods. The graphite surface complexes of the intercalated compounds and the evolved gases during expansion should be analysed.
Dissertation (MEng)--University of Pretoria, 2015.
tm2015
Chemical Engineering
MEng
Unrestricted

碩士
國立虎尾科技大學
材料科學與綠色能源工程研究所
97
PEMFC is an electrical device which directly converts chemical energy of fuel and oxidant to electricity. Compare to a heat engine or a rechargeable battery, PEMFC has high efficiency of energy transform. The main capability of a bipolar in fuel cell is to distribute fuel and oxidant to the membrane electrode and to provide electrically connection between neighboring single cells, and the cost reduction of bipolar is one of the key factors the industrialization of PEMFC. In this research, the bipolar plates are made of expanded graphite. The purpose of this paper is to study the influence of various manufacture processes on the mechanical and electrical properties of the expanded graphite bipolar plates made by stamping method. The density of the chose graphite bipolar plates is 1.6 g /cm3. The characteristic IV curves and IP curves of the fuel cells are obtained from the corresponding tests. The experimental results show that fuel cell has the best performance and optimal operating condition when the operating temperature of 45℃ is achieved in the cell. The results also reveal that the great current density of 2577.6 mA/cm2 occurs at 0.254 V, and the highest power density of 807.94 mW/cm2 occurs at 0.406 V. It is proved that the expanded graphite bipolar plate is available to be the bipolar plates of PEMFC by way of these test results.

碩士
國防大學理工學院
化學工程碩士班
102
A composite based on magnetic iron particle and expanded graphite is preparing by an explosion method and introduce into polyethylene (PE) and colloidal silicone rubber (RTV-615) to measure the infrared and millimeter wave shielding effectiveness with thermal imager and network analyzer. Microwave absorbing properties are investigate by measuring reflection loss in the 2 ~ 40 GHz microwave frequency using the free space method. The effects of structure, media material type (Carbonyl iron powder、Fe3O4) and weight ratio on the electromagnetic properties of magnetic expanded graphite are investigated. Another, the magnetic expanded graphite is introduced into the smoke container for dynamic testing with thermal imager. The spectroscopic characterizations of the formation processes of magnetic expanded graphite are examined using FTIR, XRD, SEM and VSM. These results could be a valuable reference for the shielding effect of high frequency electromagnetic wave and infrared. The results showed that the magnetic expanded graphite composites have good spectral masking properties and evenly dispersed, as the new good infrared (8~14 µm) and millimeter wave (2-40 GHz) interference materials.

碩士
國立清華大學
材料科學工程學系
100
Recently, due to the rapid developments in miniaturization of electronic devices and integrated micro/nano-electro-mechanical systems (MEMs/NEMs), thermal managements in nanoscale have become a critical issue. Traditionally, the carbon-based materials are regarded as the potential candidates due to the high thermal conductivity. Therefore, they are extensively applied to the field of composites for enhancing the thermal conductivity and other properties of polymers. In this study, we used expanded graphite (EG) prepared by using chemical intercalation method and commercial diamond powder (DP) as reinforcements, silicone as polymer matrix. First, we fabricated EG/Silicone composite specimens by three-roll mill. Second, we used hexane as solvent to disperse DP uniformly in silicone, and fabricated DP/Silicone composite specimens by electrical-magnetic stirring. Finally, we combined above-mentioned methods to fabricate EG/DP/Silicone composites specimens. In experimental design, we filled different dimension degree and grain size of reinforcements in Silicone. We measured the thermal diffusivities of composites by laser flash method, in order to calculate the thermal conductivities of composites. The effects on the mechanisms of heat conduction were also discussed. In the other hand, we used four-point probe analysis system and thermogravimetric analysis to characterize the electric insulativity and thermal stability, respectively. Finally, we observed the morphology of crossection of composites by field emission scanning electron microscope. In this study, we used expanded graphite and diamond powder with particle size between 150-180 μm as filler filled into silicone together with 3 wt% and 50 wt%, respectively. In this case, we can obtain the highest thermal conductivity, 2.41 W/m∙K.

碩士
逢甲大學
纖維與複合材料學系
104
In this study, we choose one brittle material: polycarbonate and one ductile materials: Styrene–Butadiene, and filling 0 to 5 wt% expanded graphite to reinforce their mechanical properties, the study also discusses the influence of the thickness on the mechanical properties of composite. We discusses expanded graphite/ polycarbonate and expanded graphite/ Styrene–Butadiene two composites three-point flexural, density, Shaw hardness, thermal conductivity and falling weight impact which the falling weight impact using a 9 mm pistol and 7.62 mm rifle bullet. The experimental results show that the appropriate lifting plate thickness help to improve the strength of the sheet / thickness ratio. In the performance of three-point flexural strength and impact resistance filling 0.1 wt% expanded graphite are optimum ratio, it can increase the flexural strength of about 5%, impact strength 15%.About the expanded graphite/ styrene–butadiene optimum ratio are 0.4 wt%, it can increase the flexural strength of about 16.5%, impact strength 25%.

碩士
國防大學理工學院
材料科學與工程碩士班
104
We studied the synthesis of exfoliated graphite/metal oxides (Ag2O, CuO, ZnO) for resistance the germs and toxic chemicals. The synthesized exfoliated graphite/metal oxides were characterized by SEM, XRD, ICP spectroscopy to examine the structure and physical properties. Zone of inhibition testing and the plate-counting method were used in this study to examine the antibacterial activity of the exfoliated graphite/metal oxides against Gram-negative Escherichia coli and Pseudomonas aeruginosa, and Gram-positive Staphylococcus aureus and Bacillus subtilis. Furthermore, 2-chlor-oethyl ethyl sulfide (2-CEES) was chosen to study the decontaminating efficacy of the exfoliated graphite/metal oxides with NMR. The objective of the study was to develop and evaluate these exfoliated graphite/metal oxides that can protect against simulants of chemical and biological warfare agents. Excellent antibacterial and catalytic toxic chemical degradation effects were obtained. Keywords: Exfoliated graphite, Metal oxide, Antibacterial, Degradation of toxic chemicals.

碩士
國立臺北科技大學
有機高分子研究所
96
In this study, Aluminum Tri-hydroxide, Magnesium Hydroxide and expanded graphite were used as halogen-free flame retardants to blend into polyurethane (DPU). Flame tests such as L.O.I. tester, Cone-calorimeter were employed to evaluate the best combination ratio between metal hydroxides and expanded graphite at a fixed additive amount of halogen-free flame retardant. The effect of addition halogen-free flame retardant and mechanical properties of PU were also investigated in this study. In addition, the synergistic effect of metal hydroxide and expanded graphite on flame retardant mechanism of PU was proposed. Experimental results indicated that flame retarded PU films which containing metal hydroxide or expanded graphite could gain a higher L.O.I. value. For specific optical density test, these films possessed the lower values of specific optical density. The lower values of pk-Heat release rate were also shown on cone calorimeter test for these films. To all of these flame retarded films, the DPU/ATH100 was found to be with better mechanical properties. Besides, DPU/ATH100 composite films presented better results in softness test, and this could be considered as an excellent candidate for a range of textile applications. Furthermore, for surface resistivity test, the lower surface resistivity index was obtained. Because of the addition of expanded graphite, it showed effective antistatic ability that might inhibit the burning from static electricity effect. Those films shown the better performance on fire retardancy and extinction coefficient were DPU/ATH100 and DPU/ATH60/EG40. The synergistic effect of metal hydroxide and expanded graphite on flame retardancy was investigated. The physical phenomena such as decreasing temperature and gas diluting were counted on contribution of the decomposition of metal hydroxides during its heating up. Moreover, the expanded graphite formed compact insulating layers after heating which would successfully restrain the transmission of heat and gas. It could be the reason that the better synergistic effect on flame retardancy was obtained.

博士
國立臺灣科技大學
應用科技研究所
104
Magnetic graphene (MGC) composite derived from stage-1 FeCl3–graphite intercalation compounds (GIC) was thermally treated up to 75 min at 400 °C and for 2 min at 900 °C in air. The heat treatments of the composite induced the cubical expansion of graphene with the enlargement of inter-graphene distances. Heating played a considerable role in the increase in surface area that reached 17.2 m2 g−1 during the nondefective inter-graphene exfoliation. Accordingly, the specific capacitance of MGC composite increased up to 840% of its initial value upon heating of pristine MGC composite in comparison with its value before heat treatment. Moreover, MGC heated at 900 °C (MGC-900) was hybridized with polyaniline through in situ polymerization of aniline to achieve a specific capacitance of 253 F g−1 at 5 mV s−1. Heat treatment and hybridization with a conductive polymer can effectively produce an efficient-expanded MGC composite with enhanced electrochemical activity and relatively high energy density. Separately, MGC-900 was heated at 2000 °C in vacuum atmosphere, yielding a massive expansion with well-separated layers. This exfoliation produced very thin layers including single and few-layer graphene with a surface area of 53 m2g-1. The exfoliated composite (MGC-900-2000) showed boosted electrochemical performance, with capacitive performance increasing 18 times the original value prior to heating. Additionally, the electrochemical performance of MGC under the effect of magnetic field was investigated. Various magnetic field gradients were thoroughly examined, and the effective DC power was 105 W. Capacitive performance was 40 times higher than the original value. Furthermore, when MGC-900-PANI was investigated, the capacitive routine reached 521 Fg-1 at the same scan rate. These results clearly showed the synergistic effect of the applied magnetic field on graphene exfoliation by improving its electrochemical performance. These three different experiments showed various methods of defect-less graphene exfoliation to promote its synthesis procedure as well as electrochemical performance. Moreover, the electrochemical performance under magnetic field could inaugurate a plethora of the magnetic field in energy science and technology applications.

碩士
國立臺北科技大學
有機高分子研究所
97
In this study, the submicron natural graphite (NG) and expanded graphite (EG) powders were added during the process of PMMA (Poly(Methyl Methacrylate)) in-situ polymerization to fabricate composites. In this experiment, the natural graphite powder was mixed and saturated with acids consisting of concentrated sulfuric acid, hydrogen peroxide and nitric acid to form the graphite intercalated compound (GIC). The mixed acid was an intercalant. The mixture was carefully washed and filtrated with deionized water until the pH level of the solution reached 6. After being dried at 60 ℃in a vacuum oven for 12 h, the GIC was rapidly expanded at 750 ℃ in a muffle furnace to form expanded graphite (EG). Then, it was in the course of synthesizing methyl methacrylate to form PMMA, the submicron natural graphite (NG) and expanded graphite (EG) powders with different particle sizes (3μm and 40μm) and amounts were added. To understand the composite properties, PMMA/ graphite composites were investigated by ATR-FTIR, which shows neither new groups were made nor phenomenon of displacement. The basic thermal properties of PMMA and graphite composites were investigated by thermogravimetric analyzer (TGA) and the thermal conductivity were evaluated by quick thermal conductivity meter. To consider the endurance of composites, the mechanical properties were also investigated. The dispersibility of filler in PMMA and graphite composites was obtained by studying the scanning electron microscopy (SEM).

碩士
國立高雄應用科技大學
化學工程與材料工程系博碩士班
105
The study is divided into two parts: the first part is the preparation of expanded mesocarbon microbeads (eMCMBs) by chemical oxidation of MCMB graphite powder. The eMCMBs were attached to the skeleton of nickel foam through electrophoretic deposition. After heat treatment in reducing atmosphere, the eMCMBs were converted into reduced eMCMBs (reMCMBs). The nickel foam with attached reMCMBs could be used as a highly conductive skeleton to support nickel cobaltite nanoflakes. The reMCMBs were fluffy spherical structure which could accommodate electrolyte solution, afforded current collector, and function as a stress buffer to alleviate electrode damage. Microwave synthesis of thin nickel cobaltite film with mesoporous could provide large amounts of pores for penetration of electrolyte solution, a huge interfacial area for facile redox reactions, and short transport distance for ions and electrons. Nickel cobaltite grown around nickel foam with attached reMCMBs could deliver a high specific capacitance of 260 mF cm-2 at 1.25 mA cm-2, greater than that grown around nickel foam (140 mF cm-2) and good capacitance retention (about 94％ after 2000 cycles). The second part is to deposit graphene oxide on nickel foam as skeleton to support active materials. The nickel cobaltite composite electrode was prepared by hydrothermal synthesis, followed by heat treatment in reducing atmosphere. The GO was converted into reduced GO (rGO). The interlayer distance of rGO was increased after treatment. The nickel cobaltite grown on rGO could increase the contact area between electrode and electrolyte. Nickel cobaltite grown around nickel foam with attached rGO could deliver a high specific capacitance of 680 mF cm-2 at 5 mA cm-2 and capacitance retention of about 70% after 1000 galvanostatic charge-discharge cycles.

Dissertação de Mestrado em Design e Multimédia apresentada à Faculdade de Ciências e Tecnologia
A ideia de sistemas no mundo do design não é recente. Com a criação dos primeiros manuais de identidade gráfica — onde os designers descrevem, até ao mais ínfimo detalhe, todas as regras e directrizes visuais para garantir as melhores práticas de uma marca — o conceito de sistemas no mundo design foi-se adensando.Nos dias de hoje, a utilização de sistemas no design é, sobretudo, focada no desenvolvimento de interfaces de produtos digitais e, foi neste quadro e contexto, que surgiram os design systems1. Um design system é uma coleção de componentes reutilizáveis que são guiados por estilos, padrões e regras. Quando utilizados em simultâneo, permitem a criação de qualquer número de layouts/apalicações, todos coerentes e consistentes entre si, oferecendo uma metodologia de pensar o design de forma sistemática. No entanto, esta forma ou metodologia é estritamente focada no design de interfaces e o estudo da optimização deste conhecimento e da sua utilização e aplicação a outras áreas como, por exemplo, o design gráfico, é ainda muito incipiente. A presente dissertação propõe-se a desenvolver um sistema de identidade gráfica para a empresa Dodoc. Para a criação deste sistema é importante desenvolver, em primeiro lugar, uma nova abordagem sobre a identidade de marca da empresa. Resumidamente o sistema encontra-se divido em duas plataformas, a plataforma de design e a plataforma de documentação e o seu desenvolvimento passou pela definição do seu propósito, por toda a criação dos elementos que o constituem e respectiva documentação. A criação e desenvolvimento do sistema de identidade da marca Dodoc irá ajudar a criar um universo gráfico coerente, garantindo que a marca se mantém forte e completa, capaz de crescer e de se maximizar sem descurar os valores e ideias partilhados pela empresa.
The idea of ​​systems in the design world is not new. With the creation of the first graphic identity manuals—in which designers compile a set of rules or visual guidelines to secure the best practises of a brand—the concept of systems in the design world has increased.Nowadays, the use of systems in design is, above all, focused on the development of digital product interfaces, and it was in this context that design systems emerged. A design system is a collection of reusable components that are guided by styles, patterns, and rules. When assembled together it is possible to build any number of layouts/applications, which are coherent and consistent with each other, offering a systemic design methodology. However, this form or methodology is strictly focused on the design of interfaces. The research for its usability and optimising it to other areas such as, graphic design, is still very incipient.This dissertation proposes to develop a graphic identity system for Dodoc company. To develop this system, it is important to firstly develop a new approach on the company’s brand identity. Starting by dividing it into two platforms, the design platform and the documentation platform, its development went through the definition of its purpose, the creation of all the elements that constitute it and respective documentation.The design and maturing of Dodoc brand system will support building a coherent graphic universe, ensuring that the brand remains strong and solid, capable of growing and maximising itself without neglecting the values ​​and ideas shared by the company.