As blendas de polietileno de baixa densidade (LDPE) com o polietileno linear de baixa densidade (LLDPE) são utilizadas comercialmente com o objetivo de melhorar as propriedades finais dos produtos e o seu processamento, minimizar custos de produção tendo, como seu principal segmento, filmes para embalagens. O LLDPE utilizado neste trabalho foi sintetizado a partir do catalisador de metaloceno (m-LLDPE) que foi projetado para oferecer melhores propriedades mecânicas em relação ao LLDPE sintetizado por catalisador Ziegler-Natta. O m-LLDPE quando comparado ao LLDPE (Ziegler-Natta) apresenta resistência ao impacto do dardo quatro vezes maior e resistência ao rasgo de duas a quatro vezes maior, menor temperatura de selagem e melhor processabilidade. O LDPE tem boa processabilidade, oferece grande estabilidade ao balão durante o processo de extrusão por sopro e apresenta boas propriedades ópticas. Este trabalho reúne a caracterização térmica, vibracional e ensaios físico-químicos e mecânicos, do LDPE, m-LLDPE e as blendas de LDPE/m-LLDPE na proporção em massa de 75/25, 50/50 e 25/75. Na caracterização térmica foram utilizadas as técnicas: termogravimetria (TG), calorimetria exploratória diferencial (DSC) e análise térmica dinâmico-mecânica (DTMA). Na caracterização vibracional utilizou-se a espectroscopia fotoacústica no infravermelho (PAS-IR) e espectroscopia Raman. Foi utilizada a técnica de difração de raios-X (WAXD) para complementação dos resultados. Nos ensaios físico-químicos e mecânicos foram avaliadas as propriedades ópticas, rasgo de Elmendorf, propriedades de tração, resistência ao impacto do dardo e resistência da termossoldagem à tração. Por estas técnicas foram avaliadas as características térmicas e estruturais dos polímeros e seu comportamento nas blendas. Pela técnica de DSC foi possível verificar a imiscibilidade destas blendas. As técnicas PAS-IR, Raman e WAXD apresentam perfis espectrais semelhantes não possibilitando distinção entre as blendas de composição diferentes. Os resultados de DSC, PAS-IR e WAXD mostraram que não ocorrem mudanças significativas no grau de cristalinidade das blendas. Os ensaios de brilho 45° e opacidade mostram as boas propriedades ópticas do LDPE e suas blendas. Os ensaios mecânicos mostram que o m-LLDPE e suas blendas apresenta boas propriedades mecânicas e boa soldabilidade. Foi possível determinar a blenda que é melhor indicada para os vários segmentos do mercado de embalagens. As blendas de LDPE/m-LLDPE mais utilizadas pela indústria são as de 25/75 ou 75/25, para diferentes tipos de aplicação. / Blends of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) are used commercially to improve the final properties of the products and their process, reduce the production cost having as their main segment packing film. The LLDPE used in this work was synthesized with the metallocene catalyst (m-LLDPE), which was projected to offer better mechanical properties in relation to the LLDPE synthesized by Ziegler-Natta catalyst. The m-LLDPE, when compared to the LLDPE (Ziegler-Natta) present dart impact strength four times stronger and the tearing resistance two to four times bigger, lower sealing temperature and good processability. The LDPE has good processability, offers great estability to the baloon during the process of blown extrusion and shows good optical properties. This work brings together the thermal and vibrational characterization, physical chemistry and mechanical tests, of the LDPE, m-LLDPE and the blends of LDPE/m-LLDPE in a 75/25, 50/50 and 25/75 parts by weight. In the thermal characterization several techniques were used: termogravimetry (TG), differential scanning calorimetry (DSC) and dynamic mechanical analyser (DTMA). In the vibrational characterization, the photoacoustic spectroscopy (PAS-IR) and Raman spectroscopy were used. The X-ray diffraction (WAXD) was used to complete the results. The physical chemistry and mechanical tests evaluated optical properties, Elmendorf tearing, tensile strength, dart impact strength, heat sealing strength and hot tack strength. With these techniques the thermal characterization and the polymer structure were evaluated as well as the blend behaviour. Using the DSC technique it was possible to observe that the blends are immiscible. The PAS-IR, Raman and WAXD techniques present spectral profiles not allowing a distinction between the blends with different composition. The results of DSC, PAS-IR and WAXD show that significant changes of crystallization of the blends haven\' t occurred. The gloss 45° and haze show the good optical properties of the LDPE and their blends. The mechanical tests demonstrate the good mechanical properties and soldability of the m-LLDPE and their blends. It was possible to determine the blend that best fit the different segments of the packing market. The most frequently LDPE/m-LLDPE blends used by industry are the 25/75 or 75/25, for different applications.

CHARLES UNIVERSITY Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical technology Name of the student: Nikola Hluchníková Title of diploma thesis: Solid dispersions with terbinafine Consultant: PharmDr. Eva Šnejdrová, PhD. The diploma thesis deals with the release of terbinafine base and terbinafine hydrochloride from degradable carrier in three different mediums. The carrier was polyester of lactic acid and glycolic acid branched on polyacrylic acid. The theoretical part is focused on the description of properties of drug substance and branched polyester, the bioavailability of poor soluble substances, the types of polymeric carriers and the release of drugs from solid dispersions, the thermal analysis of polymer, drug and the solid dispersion with the incorporated drug. In the experimental part, solid dispersions were prepared by the melting method, dissolution of the drug in water, phosphate buffer pH 5.5 and pH 7.4 were studied. The amount of released drug was determined spectrophotometrically at 223 nm and HPLC. A thermal analysis of polyester carriers and solid dispersions was performed by the DSC. The amount of drug released was affected by the pH of the environment. Prolonged release of terbinafine hydrochloride is carried out in a pH 7.4 phosphate solution. In case of...

Conventional processes for the manufacture of exfoliated natural vermiculite employ temperatures exceeding 800 °C and the onset temperature is above 450 °C. In many applications, notably fire retardants, it is desirable that exfoliation of vermiculite should occur at temperatures in the range of 200 °C to 350 °C. For this purpose, South African Palabora vermiculite was modified by ion exchange with ammonium and selected alkali metal and alkaline earth metal ions. These expeiments were performed at room temperature using an orbital shaker for 15 days. Another set of experiments was performed by immersing vermiculite in saturated sodium chloride solution for periods up to six months. At the end of every month, sodium-exchanged vermiculite samples were taken for analysis. The thermal expansion and degradation of modified vermiculites were studied using thermo-mechanical analysis (TMA) and thermogravimetric analysis (TGA) respectively. Interlayer composition was studied using cation exchange with ammonium acetate. The leached cations were quantitatively determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Scanning electron microscopy (SEM) was applied to study the samples’ morphology. X-ray diffraction (XRD), infrared (FT-IR) and Raman spectroscopy confirmed that the basic vermiculite crystal structure was left unchanged during inorganic modification in both sets of experiments. It was confirmed that the blowing agent in the neat vermiculite was the interlayer water. In the exchanged vermiculite with ammonium ions, it was found that ammonia and water were the blowing agents and they were simultaneously released during thermal degradation. However, ammoniumvermiculite did not show a relatively better thermal expansion ratio, despite the presence of both ammonia and water in the interlayer. In the increasing ionic potential series: Na-vermiculite, Ba-vermiculite, Ca-vermiculite and Mg-vermiculite, it was found that the onset expansion temperature also increased dramatically. Exchange with relatively low ionic potential species, namely sodium, potassium and ammonium, lowered the exfoliation onset temperature of vermiculite to below 300 °C. PORTUGUESE : Processos convencionais de produção da vermiculita natural exfoliada empregam temperaturas que excedem 800 °C e a temperatura inicial de expansão está acima de 450 °C. Em muitas aplicações, particularmente em áreas onde se deseja extinção de fogo, é desejável que a exfoliação da vermiculite ocorra na região entre 200 °C e 350 °C. Assim, a vermiculita proveniente de Palabora, África do Sul, foi quimicamente modificada com cloretos de amónio, de metais alcalinos e de metais alcalino-terrosos previamente seleccionados. As experiências foram realizadas à temperatura ambiente sob agitação constante por 15 dias. Outro desenho experimental foi executado por imersão da vermiculita em solução saturada de cloreto de sódio durante 6 meses. Mensalmente foram retiradas alíquotas de vermiculita modificada para a devida análise. A expansão e degradação térmicas das amostras da vermiculita modificada foram estudadas usando análises termo-mecânica (TMA) e termogravimétrica (TGA). O método de extracção de catiões usando acetato de amónio foi aplicado em todas as amostras e os extractos foram analisados usando plasma inductivamente acoplado ligado ao espectroscópio óptico de emissão (ICP-OES). A morfologia das amostras foi comparada usando microscopia electronica (SEM). Difracção por raios-X (XRD), espectroscopia de infravermelho (FT-IR) e Raman, confirmaram a manutenção da estrutura cristalina da vermiculita durante a reacção de troca iónica em ambas experiências. Na vermiculita nativa foi confirmada a libertação de água antes e durante a exfoliação. Na amostra de vermiculita-NH4 foi detectado amoníaco, para além da água, e ambos foram libertos simultaneamente durante a degradação térmica. Entretanto, vermiculita-NH4 não exibe uma relativamente melhor expansão térmica apesar da presença de água e amónia entre as camadas da vermiculita. Na seguinte série crescente the potencial iónico: vermiculita-Na, vermiculita-Ba, vermiculita-Ca e vermiculita-Mg, a temperatura inicial de exfoliação também é proporcionalmente crescente. Trocas catiónicas da vermiculita natural pelos seguintes iões de baixo potencial iónico: sódio, potássio e amónio resultaram na redução da temperatura inicial de exfoliação para temperaturas abaixo de 300 °C. / Dissertation (MSc)--University of Pretoria, 2011. / Chemistry / unrestricted

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Recent advances in the use of thermal proxies provide a window into how faults slip during earthquakes. Faults have a similar large-scale structure with a fault core, where earthquakes nucleate, and a surrounding damage zone, but complexities in fault zone architecture and rheology influence earthquake propagation. For example, changes in thickness of slipping layers in the fault core, compositional heterogeneity, and fault surface topography can influence fault strength and either facilitate or arrest a rupture. A further barrier to our understanding of earthquake behavior is in constraining the frictional energy that goes into the earthquake energy budget. Earthquakes can propagate when the energy available at the rupture tip is greater or equal to the energy being expended through radiation of seismic waves, permanent deformation within the process zone, and heat through friction. By quantifying the total energy involved in coseismic slip we can gain a more complete picture of the energy required for rupture propagation and how this may vary across faults. Although fracture and radiated energy can be constrained seismologically, thermal energy requires quantification by other means, and up until recently only few estimates existed for frictional energy. In this thesis I utilize biomarker thermal maturity to quantify temperature rise across multiple faults and explore what this can tell us about earthquake behavior. In chapters two through four, I focus on three large faults of varying structural and rheological complexity. Beginning with the Muddy Mountain thrust of southeast Nevada in Chapter two, I identify thermal evidence of coseismic slip in principal slip zones (PSZs) along this exhumed fault. I show that considerable heterogeneity in the thickness of slipping layers occurs a long a fault and that this has a large effect on coseismic temperature rise and hence fault strength, due to the effect of high temperature dynamic weakening mechanisms. In Chapter three, I move on to the creeping central deforming zone of the San Andreas fault, and show that it has experienced many large earthquakes that are clustered in a 4 m-wide zone adjacent to an actively creeping region. This work shows that the central San Andreas fault and other creeping faults can host seismic slip and should be included in seismic hazard analyses. Furthermore, I demonstrate the potential of K/Ar dating as a tool to constrain the age of earthquakes and find that these central San Andreas fault events are as young as ~3.3 Ma. In Chapter four, I focus on the Hikurangi Subduction zone, which has hosted large earthquakes and regular slow slip events in the past. Here, using drill core collected through the Pāpaku fault, a splay fault of the Hikurangi megathrust, I find evidence of temperature rise in the fault zone and deep hanging wall. Coupled forward models of heat generation and biomarker reaction kinetics estimate that displacement during these earthquakes was likely 11-15 m. These and other splay faults along the margin may pose considerable seismic and tsunami hazard to near-shore communities in the North Island of New Zealand. In Chapter five I explore what we have learned about fault behavior from biomarkers and other thermal proxies. I include measurements from five new faults and compile observations and measurements from past studies to explore how coseismic slip is localized across fault zones and put together a database of frictional energy estimates. Coseismic slip can broadly be described by two different scales of earthquake localization and that this is a function of total displacement, and to a lesser extent, material contrast across the fault. I see that frictional energy is relatively similar across faults of different displacement, depth, and maturity, and conclude that frictional energy is limited by the onset of dynamic weakening. Finally, I put together constraints on the energies involved in the budget to produce the first complete view of the earthquake energy budget and provide estimates of the total energy required for earthquake rupture across different faults.

The goal of the thesis was to design a piston manufactured by conventional method and subsequently adjusted one for additive manufacturing. Beside the designs, thermo-structural model was created for both pistons, considering maximal loading of the engine. Analysis evaluation showed the possibility of further application of the new technology in comparison to current one, within automotive industry.

Hydratace patří mezi nejdůležitější faktory ovlivňující sekundární strukturu a tím i funkci molekul v živých systémech. Díky vysoké afinitě tvoří molekuly vody specifické struktury jejichž složení a fyzikální vlastnosti jsou ovlivněny přítomností studované látky. Hyaluronan patří mezi biomolekuly s obrovskou schopností vázat a zadržovat vodu. Cílem této práce bylo prozkoumat hydratační vlastnosti hyaluronanu o různé molekulové hmotnosti a vyčíslit množství molekul vody v jednotlivých hydratačních vrstvách. V první části práce byla využita metoda diferenční kompenzační kalorimetrie. V druhé části diplomové práce, na základě rozdílné kompresibility, byla vázaná voda studována metodou vysoko rozlišovací ultrazvukové spektroskopie.

The degree of polymerization (DP) is the main factor which plays a role in cellulose aging. The adverse consequence of cellulose fibers aging is the deterioration of mechanical and optical properties. Viscometry is a technique which is frequently used for determination of degree of polymerization of cellulose fibers. The aim of the work was to determine the degree of polymerization of cotton fabrics and to investigate the dependence of DP on number of washing and dying. Next task was to investigate if there exists a corellation between DP and results from thermal and thermo-oxidative degradation studied by methods of thermal analysis. First, the traditional viscometry was employed to determine DP of cellulose fibers. It has been demonstrated that number of washing and dying decreases the DP. In the second part the differential scanning calorimetry (DSC) and thermogravimetry (TG) were used. DSC provided values of combustion heat and TG allowed the detail evaluation of degradation steps; obtained results were further used for correlation with DP. Methods of thermal analysis revealed differences between cotton wool and treated fabrics. Combustion heat did not show any correlation with DP. In contrast, results from TG suggested some promising correlations which could be used for the prediction of cotton fabrics DP using thermal analysis in the future.

Tato diplomová práce je zaměřena na porovnání termo-oxidační a chemické stability kovových komplexů huminových kyselin. Pro tyto experimenty byly vybrány tři prvky reprezentující skupinu těžkých kovů (kobalt, měď a nikl). Použitá huminová kyselina byla extrahována z Jihomoravského lignitu. Pro přípravu komplexů byly využito různě koncentrovaných roztoků kovů, aby bylo možné pozorovat vliv jejich počáteční koncentrace na obě studované stability připravených komplexů. Chemická stabilita kovových komplexů byla posuzována z hlediska uvolňování kovových iontů ze struktury huminové kyseliny do dvou různých extrakčních činidel (HCl, MgCl2). Termo-oxidační chování bylo zkoumáno pomocí technik termické analýzy: diferenční kompenzační kalorimetrie (DSC) a zejména termogravimetrické analýzy (TGA). Výsledky této práce přinášejí hlubší poznatky o problematice interakce kovů s humifikovanou částí půdní organické hmoty, využitelné k osvětlení problematiky kovových polutantů v životním prostředí a prohloubení žádoucích znalostí procedur jako jsou dekontaminace půdy a remediace.

The master thesis is focused on the preparing a binder system based on strontium ytritte cement and examining the physicochemical properties of the obtained system. The course of the process was evaluated using methods calorimetry, thermal analysis, X-ray diffraction analysis and scanning electron microscopy.