Este trabalho apresenta o estudo de um sistema polimérico bi-componente formado por Poli(Ácido carboxílico)-Poli(Eter-poliol), constituído primariamente de um polímero acrílico polimerizado pelo processo de polimerização em solução aquosa por mecanismo de radicais livres ao qual foi adicionado seqüencialmente, um Poli(Eter-poliol), ambos de baixo peso molecular médio. Tal sistema tem por finalidade atuar como dispersante-ligante em sistema cerâmico à base de caulim CADAM, uma vez que este sistema apresenta propriedades termoplásticas e termorrígidas a diferentes temperaturas. Foram sintetizados 03 protótipos de um sistema polimérico e o critério para escolha teve como base o pH do sistema em sentido generalizado, isto é, compreendendo as diversas fases de preparação dos polímeros e sua aplicação final. É do conhecimento comum que a reação de esterificação entre grupos COOHOH requer catálise ácida para ocorrer, o qual usualmente é realizada em pH abaixo de 4 e, neste ensaio, este pH ácido é devido à presença de ácido para-toluenosulfônico, que atua como catalisador de esterificação. Em tal intervalo de pH, em virtude do ponto isoelétrico do caulim ser comumentemente abaixo de 4, a estabilização da dispersão de caulim por repulsão eletrostática utilizando polímeros sintéticos é improvável de ocorrer, razão pela qual buscou-se mecanismos alternativos para obtenção de uma tal estabilização, entre os quais o mecanismo estérico surge como opção. O sistema polimérico do presente estudo apresenta-se na forma de uma solução aquosa sendo, de fato, uma mistura homogênea de um copolímero de ácido acrílico, N- metiloacrilamida e metacrilato de metoxipolietileno glicol e um poli(eter-poliol). O poli(eter-poliol) e N-metilolacrilamida presentes no sistema polimérico são principais fontes de grupo hidroxila para reação de poliesterificação e formação de ligações cruzadas à temperatura de 150 a 200 °C. No estado termoplástico o sistema polimérico produzido pela mistura poli(ácido carboxílico)-poli(eter-poliol) pode ser utilizado como dispersante de argilas com especial fóco sobre caulim como tratado neste trabalho. A propriedade dispersante pode ser atribuida à presença de grupos carboxílicos e metoxipolietilenoglicol aleatoriamente distribuídos ao longo da cadeia polimérica e, também, ao baixo peso molecular médio. A temperaturas entre 150 a 200 °C, o polímero é reticulado (crosslinked) por reação de poliesterificação, catalisada por ácido, entre grupos carboxila e grupos hidroxila, sendo as hidroxilas provenientes tanto de poliol como de N-metilolacrilamida (NMAM). Assim, do ponto de vista térmico comporta-se como termorrígido, sendo nesta condição insolúvel em água e adequado atuar como ligante na manufatura de materiais cerâmicos. Medidas de mobilidade eletroforética e viscosidade são aplicadas à caracterização de caulim e do sistema polimérico a fim de avaliar a potencialidade de aplicação como dispersante desta argila. Também, as transições dos estados termoplásticos para termorrigidos foram determinadas por análise termogravimétrica (TG) e análise dinâmico mecânica (DMA) nos polímeros isoladamente e depois com medidas de resistência mecânica do sistema caulim/polímero. O sistema apresentou comportamento dispersante em água e ligante após cura. Um sistema polimérico assim sintetizado foi propriamente curado por calor tornando- se, na forma termorrígida, um ligante para peças cerâmicas com propriedades mecânicas de alto desempenho, como resistência a flexão no estado cru (green strenght). / This work presents the study of a polymeric bi-component system made from Poly(carboxylic acid)-Poly(ether-polyol) primarily constituted of an acrylic acid polymerized through the process of aqueous solution polymerization by free radical mechanism, to which a poly(ether-polyol) has been sequentially added, both of them of low average molecular weight. Such a system has the aim to act as dispersing-binding balance on CADAM kaolin targeting to evaluate the applicability potential or the preparation of ceramic bodies as this polymeric system presents thermoplastic and thermosetting properties at different temperatures. Were made the synthesis of 03 polymeric system prototypes which criteria for choice was based on pH of the system at whole sense, that is, regarding the several steps for polymers preparation and its final application. It is knowledge that esterification reaction between COOH-OH groups requires acid catalyst to occur, which usually is done at pH below 4 and, in this work this pH is due to p-toluene sulfonic acid that act as esterification catalyst. In this range of pH, due to the isoeletric point of kaolin to be below 4 the electrostatic stabilization of dispersion is unlikely to occur, from which reason was looked for an alternative mechanism to achieve the dispersion stabilization, among them the steric mechanism arises an option. The polymeric system of this study is the form of an aqueous solution, which actually is a homogeneous blend of a copolymer of acrylic acid, N-Methylolacrylamide Methoxypolyethyleneglycol Methacrylate (MPEGMA) and Poly(ether-polyol). The Poly(etherpolyol) and the N-Methylolacrylamide presents at the polymeric system are the main sources of hydroxyl groups to enhance the polyesterification reaction for further crosslinking at temperatures from 160 to 200 °C. At the thermoplastic state the polymeric system made by Poly(carboxilic acid)poly(ether-polyol) macromolecules may be used as clay dispersant focusing on kaolin for this work. The dispersant property may be attributed to the carboxylic and methoxypolyethyleneglycol group randomly distributed along the polymeric chain backbone and, also to the low average molecular weight. At temperatures between 150 to 200 °C, the polymer is crosslinked by polyesterification reaction catalized by acid between carboxyl groups and hydroxyl groups, in such way that hydroxyls groups comes both from the polyol base polymer and NMethylolacrylamide (NMAM) present at first polymer backbone. Thus, through a thermal standpoint it behaves as thermoset being that, under this condition, water insoluble and adequate to act as binder for manufacturing of ceramic materials. Electrophoretic mobility and viscosity measurements were applied for the characterization of kaolin and the polymeric system targeting to the evaluation its potential application as a dispersant for this clay. Also, the transitions from the thermoplastic to the thermoset state have been determined by thermo-gravimetric analysis (TG) and dynamicmechanical analysis (DMA) for the Poly(carboxylc acid)poly(ether-polyol) polymers alone and further by mechanical resistance measurements for a clay-polymer system. The system has presented both dispersant behavior on aqueous media and binder just afterward cure. A polymeric system thus synthesized was properly cured by heat turning and then, at the thermoset state, become suitable for act as a binder for ceramic bodies with high performance mechanical properties measured as flexural resistance at green strength.

This diploma thesis is focused on the design of a rotating rectifier for a synchronous generator. Based on defined requirements, the new rotating rectifier concept has been created that allows a greater current range than existing rectifier used by Siemens Electric Machines s.r.o. The thesis is divided into five parts. The first part deals with the search of existing rotating rectifiers and other design possibilities. The requirements for the rotating rectifier were defined in the second part of the thesis. The following section deals with both electrical design of rectifier elements and varistors. The fourth part of the diploma thesis describes the thermal analysis. On the basis of thermal analysis the operating conditions of the rotating rectifier were determined. The last part of the thesis is devoted to mechanical and modal analysis. Based on these analyses, the strength and operability of the new rotating rectifier concept were verified.

The presented diploma thesis deals with the evaluation of the influence of the addition of 30, 60 and 90 % of recycled material on the structure and mechanical properties of high-density polyethylene (HDPE), where recycled material represents both HDPE from a several years old part and material multiple reprocessed by extrusion. The changes of supramolecular structure were examined by calorimetric measurement, which did not indicate degradation of the material due to multiple extrusion. Mechanical properties were investigated by tensile tests and dynamic-mechanical analysis. Both measurements showed the same trend, where the first and second pass of the material through the extruder led to improved mechanical properties, e.g. to increase stiffness, while the influence of the third and fourth passes through the extruder had not a significant effect on the mechanical properties. In terms of the structure and mechanical properties, a positive effect of the combination of material after the second extrusion passing (30%) with virgin material was recorded.

The objective of this master’s thesis is to simulate thermo-mechanical behaviour of nuclear fuel in a pressurized water reactor during a reactivity initiated accident. An important part of this work is focused on examination of processes which occur during such accident and on creation of a detailed overview of material properties of nuclear fuel and fuel cladding which are necessary for simulations that closely reflect reality. Simulations in this thesis examine cases of fresh or irradiated nuclear fuel for two types of fuel cladding, Zircaloy-4, a material that is currently used in nuclear reactors, and ceramic matrix composite material made of SiC. The thesis also presents comparison of results with a corresponding international benchmark and an assessment of the influence of selected input parameters on obtained results.

Dan Beaty (1937-2002) was a prolific composer, pianist, researcher, educator, and writer. His large compositional output included chamber works, choral works, songs, orchestral pieces, electronic music, and keyboard works. Beaty was well versed in traditional Western music as well as the more avant-garde and perplexing idioms of the twentieth century. Beaty's compositions reflect the many fascinating, if not always popular, musical trends of his time. His music encompasses styles from serial to jazz, shows compositional influences from Arnold Schoenberg to Indonesian music, and demonstrates thought-provoking and highly intellectual craftsmanship. This document explores several of Beaty's songs through a discussion of the composer's life and compositional process. Songs included in this document are Three Weeks Songs, October, November, A Sappho Lyric, Love Song, That Night When Joy Began, and War Lyrics. This document was written to accompany the author's DMA Lecture-Recital at the University of North Texas. Unfortunately, Beaty's vocal music was never published and is mostly unknown. One goal of the project was to initiate interest in Beaty's songs. Through this document, Lecture-Recital, and additional performances, considerable strides have been made to bring Beaty's songs to new audiences throughout the United States. In addition, the author has received permission from the Beaty family to publish Dan Beaty's songs.

Indiana University-Purdue University Indianapolis (IUPUI) / Understanding the mechanical properties of peripheral nerves is essential for chronically implanted device design. The work in this thesis aimed to understand the relationship between local deformation responses to global strain changes in peripheral nerves. A custom-built mechanical testing rig and sample holder enabled an improved cyclical uniaxial tensile testing environment on rabbit sciatic nerves (N=5). A speckle was placed on the surface of the nerve and recorded with a microscope camera to track local deformations. The development of a semi-automated digital image processing algorithm systematically measured local speckle dimension and nerve diameter changes. Combined with the measured force response, local and global strain values constructed a stress-strain relationship and corresponding elastic modulus. Preliminary exploration of models such as Fung and 2-Term Mooney-Rivlin confirmed the hyperelastic nature of the nerve. The results of strain analysis show that, on average, local strain levels were approximately five times smaller than globally measured strains; however, the relationship was dependent on global strain magnitude. Elastic modulus values corresponding to ~9% global strains were 2.070 ± 1.020 MPa globally and 10.15 ± 4 MPa locally. Elastic modulus values corresponding to ~6% global strains were 0.173 ± 0.091 MPa globally and 1.030 ± 0.532 MPa locally.

Structures made of the thermoplastic polymer polyether ether ketone (PEEK) are widely used in dynamically-loaded applications due to their high-temperature resistance and high mechanical properties. To design these dynamic applications, in addition to the well-known stiffness and strength properties the vibration-damping properties at the given frequencies are required. Depending on the application, frequencies from a few hertz to the ultrasonic range are of interest here. To characterize the frequency-dependent behavior, an experimental approach was chosen and applied to a sample polymer PEEK. The test setup consists of a piezoelectrically driven base excitation of the polymeric specimen and the non-contact measurement of the velocity as well as the surface temperature. The beam’s bending vibrations were analyzed by means of the Timoshenko theory to determine the polymer’s storage modulus. The mechanical loss factor was calculated using the half-power bandwidth method. For PEEK and a considered frequency range of 1 kHz to 16 kHz, a storage modulus between 3.9 GPa and 4.2 GPa and a loss factor between 9 103 and 17 103 were determined. For the used experimental parameters, the resulting mechanical properties were not essentially influenced by the amplitude of excitation, the duration of excitation, or thermal degrad.ation due to self-heating, but rather slightly by the clamping force within the fixation area.

This thesis, conducted in collaboration with IKEA Components, explores the rate-temperature dependence of polyoxymethylene (POM) thermoplastic using dynamic mechanical thermal analysis (DMTA). A force-controlled DMTA study was carried out, and the experimental data were processed to derive the complex, storage, and loss modulus. Master curves were constructed using the time-temperature superposition (TTS) method, comparing the Arrhenius and William-Landel-Ferry (WLF) equations. Additionally, a master curve was manually created by shifting isothermal material properties. This manual curve was then compared to those generated using standard equations. The study found that the storage modulus was the dominant phenomenon in POM, with the loss modulus showing distortion likely due to measurement noise. Results indicated a slight softening of the storage modulus with increased cyclic loading. The manually constructed master curve was more coherent compared to those derived from the Arrhenius and WLF equations.

Additives, incorporated in film coating formulations, and their process parameters are generally selected using a trial-and-error approach. However, coating problems and defects, especially those associated with aqueous coating systems, indicate the necessity of embracing a quality-by-design approach to identify the optimum coating parameters. In this study, the feasibility of using thermal and rheological measurements to help evaluate and design novel coating formulations has been investigated. Hydroxypropyl methylcellulose acetate succinate (HPMCAS), an enteric coating polymer, was used as the film forming polymer. Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), and Parallel Plate Shear Rheometery (PPSR) were used to evaluate the effect of different plasticisers on the performance of HPMCAS. The results illustrate that, for identical formulations, the DSC and DMA methods yielded up to 40% differences in glass transition temperature (Tg) values. Moreover, Tg measured using loss modulus signals were always 20-30 oC less than those measured using tan delta results in DMA testing. Absolute and relative Tg values can significantly vary depending on the geometry of the samples, clamp size, temperature ramping rate and the frequency of the oscillations. Complex viscosity data for different formulations demonstrated a variable shear thinning behaviour and a Tg independent ranking. It is, therefore, insufficient to rely purely on Tg values to determine the relative performance of additives. In addition, complex viscosity results, obtained using both the DMA and PPSR techniques at similar temperatures, are shown to be comparable. The results from both techniques were therefore used to produce continuous master curves for the HPMCAS formulations. Additionally, step strain tests showed that HPMCAS chains do not fully III disentangle after 105 seconds as predicted by the Maxwell model. Finally, in situ aqueous-based coating experiments proved that mixtures of triethyl acetyl citrate and acetylated monoglyceride (TEAC/AMG), even without cooling of the suspension, do not cause blocking of the spray nozzle whereas triethyl citrate (TEC) based formulae did. TEAC (alone or in a combination with AMG) exhibits superior wettability to HPMCAS than TEC/AMG formulations and can be used to enhance the efficiency and film quality of the dry coating process.

Composites are the materials which can be used for a wide variety of applications andproducts such as sports equipment, aerospace and marine because of light and stiffnessproperties. Composites are often made from thermoset resin with glass fibers.In this study, two ways of recycling composites were evaluated, which are microwavepyrolysed composites (MGC) and mechanical composites (GC). These glass fibers weregoing to be compounded with Polypropylene (PP) or Maleic Anhydride ModifiedPolypropylene (MAPP) and then injection moulded the sample by Micro-compounder.In order to get better adhesion to the polymer, a coating was added. The Neoxil 5682-polypropylene water emulsion was evaluated.The samples were characterized by Tensile Testing, Thermogravimetric Analysis (TGA),Different Scanning Calorimetry (DSC), and Dynamic Mechanical Analysis (DMA) to find aoptimum combination of recycled glass fiber reinforced polymer.Microwave pyrolysis is a new research area. The glass fiber, polymer oil and gas can beobtained by heating the composite with microwaves to in an inert atmosphere. The polymeroil can be distillated and then evaluated with GC-MS; in order to obtain the chemicalcompositions.Keywords: Composites, grinded and microwave pyrolyse composites (MGC), grindedcomposites (GC), Polypropylene (PP), Maleic Anhydride Modified Polypropylene (MAPP),Micro-compounder, Tensile Testing, Thermogravimetric Analysis (TGA), Different ScanningCalorimetry (DSC), and Dynamic Mechanical Analysis (DMA), Microwave pyrolysis,polymer oil, distillation, GCMS Analysis. / Program: MSc in Resource Recovery - Sustainable Engineering