C'est dans un contexte marqué par une demande croissante en énergie primaire, une diminution des ressources et dans un souci de protection de l'environnement que le biocarburant de 2ème génération est développé. Cependant, ce biocarburant est non viable économiquement. L’optimisation, le contrôle et la connaissance des cinétiques régissant les procédés de fabrication de ce bioéthanol sont donc des éléments capitaux. Dans cette étude, le potentiel de la calorimétrie isotherme pour surveiller les réactions d'hydrolyse et de fermentation est testé.Les résultats montrent que cette méthode est efficace. En effet, celle-ci a permis de mettre en évidence l'importance du ratio enzyme/substrat pour maximiser le rendement et de déterminer un meilleur cocktail composé de cellulases + cellobiose déshydrogénase (CDH) qui permet la production d'une certaine quantité d'acide gluconique, qui pourrait améliorer l'attractivité de ce biocarburant. Ces mêmes essais ont également permis de déterminer la chaleur de l'hydrolyse de la paille de blé, qui est 32,18 ± 3,18 J.g-1 (gramme de sucres produits).Les mesures obtenues ont été utilisées pour déterminer les constantes cinétiques des cellulases + CDH sur la paille de blé et les résultats montrent que ce cocktail enzymatique est plus rapide à 45 °C dans la gamme de températures testée (40-55°C) avec une vitesse de 7,36 ± 0,62 mmol/L.min.Par ailleurs, les essais avec un calorimètre à échelle laboratoire ont montré que même si celui-ci ne mesure pas avec précision les chaleurs engendrées par les réactions d'hydrolyse et de fermentation, celui-ci donne de bonnes indications sur le déroulement et l'avancement de ces réactions. / Second generation biofuel is developed in a context marked by an increasing demand for primary energy, a decrease in resources and in environmental protection concernsHowever, this biofuel is not economically viable. Optimization, control and knowledge of the kinetics governing this bioethanol production processes are crucial elements.In this study the potential of isothermal calorimetry to monitor hydrolysis and fermentation reactions is tested.The results show that the isothermal calorimetry is an effective method. Indeed this method allowed determining that the substrate/enzyme ratio is an important parameter of the hydrolysis yield.Furthermore it has determined a better enzyme cocktail consisting of Cellulases + Cellobiose Dehydrogenase (CDH) which allows the production of a certain amount of gluconic acid, which could improve the attractiveness of these second-generation biofuels. These same tests also determined the hydrolysis heat of wheat straw which is 32.18 ± 3.18 J.g-1 (gram reducing sugars product).The measurements obtained were used to determine kinetic constants cellulases + CDH on wheat straw and the results show that this enzyme cocktail is faster at 45 ° C in the range of temperatures tested (40 - 55°C) with a speed of 7.36 ± 0.62 mmol/L.min.In addition, testing with a laboratory-scale calorimeter showed that even if this tool does not accurately measure the heat generated by the hydrolysis reaction and fermentation, it gives a good indication of the development and advancement of these reactions.

Orientador: Edvaldo Sabadini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-26T20:28:41Z (GMT). No. of bitstreams: 1 Clinckspoor_KarlJan_M.pdf: 16885506 bytes, checksum: bf5bdbaa99957493be29510c93bbd89d (MD5) Previous issue date: 2015 / Resumo: O papel estrutural de cossolutos derivados de cinamato para a formação de micelas gigantes de surfactantes catiônicos. Micelas gigantes (MG) são estruturas de autoassociação de surfactantes que podem ser formadas pela adição de cossolutos aromáticos, como salicilato, a soluções de surfactantes catiônicos como CTAB e TTAB (brometo de cetiltrimetilamônio e brometo de tetradeciltrimetilamônio). Estudou-se o papel de derivados estruturais do ácido cinâmico (C6H6-CH=CH-COOH), a saber, ácido ortohidroxicinâmico (OHCA), ácido ortometoxicinâmico (OMCA), ácido ortohidroxifenilpropiônico (OHPA), ácido 3-fenilpropiônico (3PPA) na formação de MG de CTAB e TTAB, em pH 6, e também foi estudada a variação de pH de soluções com OHCA, entre pH 6 e 11. As técnicas principais utilizadas foram: Reologia oscilatória, Espalhamento estático de luz (SLS), Calorimetria de titulação isotérmica (ITC), Espalhamento de raio X em baixo ângulo (SAXS) e Microscopia de transmissão eletrônica em temperaturas criogênicas (Cryo-TEM). Variando a estrutura dos cossolutos, foi possível observar que tanto a presença da ligação dupla do cinamato quanto a de uma hidroxila na posição orto contribuem para a formação de MGs. Quando o cossoluto possui esses dois grupos, que é o caso do OHCA, as micelas são formadas em proporções muito baixas de [TTAB]/[Cossoluto], como foi visto por ITC. Quando o cossoluto possui somente um dos grupos, a formação de micelas ocorre em proporções maiores (OHPA, OMCA, Cinamato) e quando possui nenhum dos dois grupos (3PPA), não são formadas micelas gigantes. As estruturas das micelas de cada região do ITC foram inferidas por SLS e ensaios viscosimétricos. Variando-se o pH das soluções de OHCA com TTAB, observou-se que quanto maior o pH, as micelas são formadas em proporções maiores e a entalpia de formação é menor. Por reologia, foi visto que em pH 9, o sistema formado possui um tempo de relaxação muito maior que em pHs 6-8, em pH 10 o sistema não é mais Maxwelliano e em pH 11, a solução é fluída como água. Isso ocorre porque, quanto maior o pH, o OHCA se torna mais hidrofólico e menor é sua partição no interior da micela / Abstract: The structural role of cossolutes derived from cinnamate in the formation of cationic surfactante wormlike micelles. Wormlike micelles (WLM) are surfactant self-assembly structures that can be formed by the addition of aromatic cossolutes, like salicylate, to solutions of cationic surfactants like CTAB and TTAB (cetyltrimethylammonium bromide and tetradecyltrimethylammonium bromide). We studied the structural role of structural derivatives of cinnamic acid (C6H6-CH=CH-COOH), namely, orthohydroxycinnamic acid (OHCA), orthomethoxycinnamic acid (OMCA), orthohydroxyphenylproprionic acid (OHPA), 3-phenylpropionic acid (3PPA) on the formation of wormlike micelles of CTAB and TTAB, at pH 6. We also studied the variation of pH, ranging from 6 to 11, on OHCA WLM. The main techniques used were: Oscillatory rheology, static light scattering (SLS), isothermal titration calorimetry (ITC), small angle x-ray scattering (SAXS) and cryogenic temperature transmission electron microscopy (Cryo-TEM). By varying the structure of the cossolutes, it was possible to see that both the presence of a double bond and an ortho-hydroxyl favor the formation of WLM. When the cossolute has both groups (OHCA), the WLM are formed at very low [TTAB]/[Cossolute], as was seen by ITC. When the cossolute has only one of those groups the WLMs are formed at higher proportions (OHPA, OMCA, Cinnamate) and when it doesn't have either groups (3PPA), no WLMs are formed. The structures at each concentration region were inferred by viscosimetry and SLS. When varying the pH of OHCA, it was observed that the higher the pH, the proportion for the formation of WLM is increased, and the enthalpy of formation is smaller. By rheology it was seen that at pH 9, the system formed has a much higher relaxation time than at pH 6-8, at pH 10 the system isn't Maxwellian and at pH 11, the system is liquid. This occurs because by increasing the pH, the hydrophilicity of OHCA is increased, and smaller is its partition on the WLM palisade / Mestrado / Físico-Química / Mestre em Química

The presented diploma thesis deals with the study of interactions between humic acids as the main component of soil organic matter with a model organic pollutant presented by cationic surfactant Septonex (which was expected to interact positively with humic acids due to its charge) through unconventional combination of dialysis and diffusion techniques realized in diffusion cells together with isothermal titration calorimetry capable of elucidating the nature of ongoing reactions from a thermodynamic point of view. The experiments were performed with a humic acid isolated by standard isolation procedure from Leonardite (1S104H) purchased from the International Society for Humic Substances, with humic acids isolated from lignite as well as modal chernozem. The aim of the submited diploma thesis is to assess the influence of carboxyl functional groups in the structure of humic acids to interactions with Septonex. For this reason, said samples of humic acids have been modified by selective methylation of their carboxyl functional groups, which can no longer participate in interactions with ionic substances. Results from diffusion cells and isothermal titration calorimetry confirmed the assumption that Septonex interacted with all types of unmodified humic acids more than with their methylated derivatives. Despite the available literature, it was surprising that the differences in the interaction of humic acids with Septonex were not diametrically different when comparing unmodified humic acids with their methylated derivatives. The extent of these interactions was assessed through the apparent equilibrium constant Kapp determined in the diffusion (dialysis) experiments and from the course of enthalpy curves from isothermal titration calorimetry. After the experiments and their evaluation, it can be concluded that humic acids and Septonex in their interactions, due to their structures, probably apply not only electrostatic interactions, especially through available carboxyl functional groups of humic acids and positively charged hydrophilic parts of Septonex molecules, but also a significant role have a hydrophobic effect, hydrogen bonds and Van der Waals forces.

Early detection of pathogenic bacteria in food, drinking water and medicine products is one of the essential tasks of routine microbiological analysis. Through analytics, outbreaks can be discovered and consequently, countermeasures can be initiated to minimize health and economic damage. Cultivation of pathogens from contaminated specimens is routinely performed in microbiological laboratories worldwide. The procedure is easy to perform, requires little equipment and provides simple quantitative data in colony-forming units (CFUs) per sample volume. Only the time between preparation and confirmation of a positive (contaminated) sample usually extends over several days. The desired goal should be a technique that can retain the simplicity of cultivation while providing real-time information about the sample under investigation for early detection of potential contamination. Therefore, in the framework of this thesis, systematic heat flow measurements were performed on two model strains, Lactobacillus plantarum DSM 20205 and Pseudomonas putida mt-2 KT2440. The influence of cultivation techniques (in liquid, on solid and membrane filter placed onto solid medium) in static ampoule systems on calorimetric detection was investigated. In particular, the effect of contamination level (initial bacterial cell number), substrate amount (nutrients and oxygen), and detection limits were systematically evaluated. In addition, microcalorimetric measurements of Legionella pneumophila ATCC 33152, a waterborne pathogen, were conducted for the first time. Heat flow profiles demonstrated that high contamination levels (> 1000 CFU) were detected within 24 h. Compared to detection times of up to 10 days by ISO 11731:2017, calorimetric detection can serve as an early warning system. With this knowledge, a uniquely manufactured micro(bio-)calorimetric test system was designed to meet the requirements for detecting bacterial contaminations. In particular, the sample vessel geometry and the operating temperature perfectly matched the microbiological analysis. Within this development work, numerical models were established to investigate the temperature distribution of selected compounds as well as the complete calorimetric system. Based on these models, modifications to the test system were numerically simulated in advance to improve the instrument's performance stepwise. This thesis presents the methodological principles and a calorimetric test system designed as an early warning and detection tool for microbiological samples.

The main object of the diploma thesis is study of interaction beetween humic acids and selected metal ions using calorimetric titration. The research about reactivity of humic substances is done comparing the different models used to describe the variety of properties of humic substances. In experimental part the methods of FT-IR spektrometry, potenciometric and conductometric titration are used to recieve the total acidity and carboxylic acidity of lignite humic acid. The optimalization of isothermic titration calorimetry is done to be used within study of reactivity of humic acids, revealing the best correlation with sols of studied humic acid. The basic organic compounds were used including benzoic acid, ftalic acid, salycilic acid, pyrocatechol and phenol as models of bonding groups in humic acids. The reaction enthalpy was calculated from the titration of models and results were compared with semiempiric quantum chemistry calculations following INDO method.

The aim of this graduation thesis is to investigate whether it is possible to design a fluid machine that would utilize a flow resulting from different densities of processing medium, to generate electricity. The thesis focuses on the determination of relations that have influence on the efficiency. The parametres influencing the degree of efficiency have been analyzed. The aim is to reach the highest possible degree of efficiency. Depending on the results, a suitable processing medium can be selected. Within the scope of the thesis, an experiment had been proposed that verified the ground principle of the non-isothermal flow occurence. In conclusion, the outcomes are evaluated with the view of a prospective further developement of the device.

Graduation theses consist of two parts. The first one, theoretical is focused on piece of knowledge regarding nodular iron history, its mechanical properties, chemistry, production and heat treatment. Theoretical part also includes information relating to graphite and white irons that relate closely with nodular iron. Important chapter is description of isothermal refining which is the subject of these theses. The second, experimental part is focused on isothermal refining of nodular iron casting. Description of the casting introduces this section, material specification, production and application. Following chapters describe preliminary conditions for isothermal refining that is applied on every single specimen made of the casting. These specimens have been tested mechanically. Optimal procedure of isothermal refining is applied on whole the casting and characterized final mechanicals. Final mechanical properties after casting isothermal refining has been analyzed and confronted with literature.

Vliv hyaluronanu na micelizaci tenzidů byl studován různými fyzikálně-chemickými metodami. Byly zvoleny dva kationaktivní tenzidy, a to tetradecyltrimethylammonium bromid (TTAB) a cetyltrimethylammonium bromid (CTAB). Metoda izotermické titrační kalorimetrie byla využita pro stanovení entalpie micelizace, tenziometrie popisuje povrchové vlastnosti daných vzorků. Byl sledován také vliv různé molekulové hmotnosti použitého hyaluronanu a délka alkylového řetězce tenzidu na agregační chování daného systému. Výsledkem jsou hodnoty kritické micelární nebo agregační koncentrace tenzidu. V neposlední řadě se diskutuje využití agregátů hyaluronan-tenzid jako možné nosiče pro cílenou distribuci léčiv.

<div>Pathogen identification at the point of use is critical in preventing disease transmission and enabling prompt treatment. Current rapid diagnostic tests suffer from high rates of false negatives because they are not capable of detecting the inherently low concentrations of pathogens found in early stages of infection or in environmental reservoirs. The gold standard method for timely pathogen identification is a nucleic acid amplification assay called polymerase chain reaction. Although polymerase chain reaction is extremely sensitive and specific, it requires expensive laboratory equipment and trained personnel to perform the sample preparation, cyclical heating, and amplicon analysis. Isothermal nucleic acid amplification assays are better suited for field use because they operate at a single temperature and are robust to common sample matrix inhibitors. Thus, there is a need to translate isothermal amplification assays to the point of use for rapid and sensitive detection of pathogens in complex samples.</div><div><br></div><div>Here, I outline an approach to bring laboratory-based sample preparation, assays, and analyses to the point of use via portable platforms. First, I characterize a loop-mediated isothermal amplification assay and combine it with lateral flow immunoassay for simple, colorimetric interpretation of results. Next, I optimize an ambient-temperature reagent storage method to eliminate cold-chain requirements and precision pipetting steps. I then incorporate loop-mediated isothermal amplification, lateral flow immunoassay, and reagent drying into two different integrated paperfluidic platforms and demonstrate their ability to separately detect bacteria and viruses in complex sample matrices. Finally, I couple loop-mediated isothermal amplification with particle diffusometry to optically determine pathogen presence by tracking the Brownian motion of particles added to an amplified sample. The combined loop-mediated isothermal amplification and particle diffusometry method is first characterized on a microscope and then translated to a smartphone-based platform. Each of these portable platforms are broadly applicable because they can be easily modified for identification of other pathogens at the point of use.</div>

Ultra-high performance concrete (UHPC) has progressively gained interest because of its favorable strength and durability properties. Literature shows that curing temperature has a significant effect on the resultant mechanical properties of UHPC, generally resulting in increased compressive strength. However, limited datasets are currently available to ascertain the degree of change related to compressive strength as a function of curing temperature and conditions. This study investigates the effect of isothermal and submerged curing temperature conditions, ranging from 10°C to 90°C, on the compressive strength and elastic modulus development of UHPC and generates a numerical model to capture these effects. The extent and rate of compressive strength development in Cor-Tuf UHPC was found to increase with curing temperature, while only the rate of elastic modulus development increased with curing temperature. The numerical model shows reasonable agreement when compared with the experimental results and was successfully implemented in finite element analysis software.