Разработаны составы масс для производства керамических кордиеритовых субстратов различными способами формования: полусухим и пластическим формованием. Проведенные исследования показывают возможность получения кордиеритовой керамики на основе сырья отечественных месторождений с высоким содержанием кордиерита. / Mass compositions to produce ceramic cordierite substrates by various molding methods have been developed: semi-dry and plastic molding. The conducted studies show the possibility of obtaining cordierite ceramics based on raw materials from domestic deposits with a high content of cordierite.

Polylactic acid (PLA) is an aliphatic polyester, derived from sustainable natural sources that is biodegradable and can be industrially composted. This material has been in the spotlight recently due to its sustainability and properties. However it has been invented in 1932 by Carothers and then patented by DuPont in 1954 (Standau et al. 2019). The properties of this material though limit its use for applications mainly in the medical sector and in some cases single use packaging. In this research, PLA based blends with improved rheological and thermomechanical properties are investigated. The focus is based in proposing strategies in improving these properties based on commercial methods and processing techniques. In this work, commercial grade PLA has been blended with polycaprolactone (PCL) and polybutylene succinate (PBS) in binary and ternary formulations via twin screw extrusion. PCL has been known to act as an impact modifier for PLA, but to cause a corresponding reduction in strength. Results showed that the binary PLA blends containing PBS and PCL, had reduced viscosity, elastic modulus and strength, but increased strain at break and impact strength. Morphological and thermal analysis showed that the immiscibility of these additives with PLA caused these modifications. Incorporation of a small loading of PBS had a synergistic effect on the PLA-PCL blend properties. Miscibility was improved and enhanced mechanical properties were observed for a ternary blend containing 5wt% of both PBS and PCL compared to binary blends containing 10% of each additive. To increase heat resistance of PLA, the material’s crystallinity has to be increased. However PLA has a relatively slow crystallisation rate making it difficult and expensive to be used in commercial applications where heat resistance is needed. For this reason the chiral nature of PLA has been used to investigate the effect of stereochemistry of PLA in crystallisation. Optically pure PDLA was added to its enantiomer in small amounts (up to 15%) and the properties and crystallisation mechanism of these blends was investigated. Results showed that the addition of PDLA accelerated crystallinity and developed a stucture that increased heat resistance, melt strength and stiffness. Finally, a processing model of developing a fully stereocomplex PLA part based in commercial techniques is proposed. Injection moulded PLA showed even higher heat resistance without the need of further processing the product (increasing crystallinity). / Floreon

Bacterial spore peptidoglycan (PG) is very loosely cross-linked relative to vegetative PG. Theories suggest that loosely cross-linked spore PG may have a flexibility which contributes to the attainment of spore core dehydration. The structure of the PG found in fully dormant spores has previously been examined in wild type and many mutant strains. These analyses showed little correlation between the degree of spore PG cross-linking and core dehydration. However, these studies only examined the structure of PG from dormant spores and did not allow for the structural analysis of spore PG during sporulation when actual spore PG synthesis and core dehydration occur. Structural analyses of developing spore PG from wild type Bacillus subtilis and eight mutant strains are included in this study. Structural analyses of developing spore PG suggest the following: a) the germ cell wall PG is synthesized first next to the inner forespore membrane; b) cross-linking is relatively high in the first 10% of spore PG synthesized; b) a rapid decrease in cross-linking is observed during synthesis of the next 20% of the spore PG; and c) this decrease is followed by an eightfold rise in the degree of cross-linking during synthesis of the final 70% of the spore PG. This increasing gradient of cross-linking was previously predicted to contribute to the attainment of spore core dehydration. However, analyses of mutant strains indicate this cross-linking gradient is not required for the attainment of spore dehydration. / Master of Science

Med olika ISO-standarder och artiklar som bakgrund har   Woolpowers sovsäckslakan Sleeping Bag   Liner:s värmeresistans (isolerande förmåga) undersökts på tre olika   sovsäckar. Med hjälp av en docka med termologiska egenskaper har värden för   värmeresistansen tagits fram. Vidare överfördes värdet till en skala för   temperatur, i vilken komfort-, övergångs- och extremtemperatur erhölls.   Samtliga sovsäckar uppvisade en tydlig ökning i värmeresistansen när   sovsäckslakanet användes, vilket i förlängningen betydde att   temperaturgränserna också förändrades. Ett konkurrerande sovsäckslakan blev även testat. Dels   för att undersöka hur Woolpower står sig mot en av de övriga producenterna på   marknaden, dels för att kritiskt granska den information som förmedlas till   konsumenter av produkten samt för att diskutera huruvida dem graderingarna   som används idag kan förändras för att ge konsumenten tydligare information   om produkten. I jämförelsen mellan Woolpower och konkurrenten visade det sig   att Woolpowers hade en högre ökning av värmeresistansen i samtliga sovsäckar.   Detta öppnar upp för en frågeställning, då konkurrenten påstår   på sin produkt att den potentiellt ska öka sovsäckstemperaturen med upp till   15°C. Enligt föreliggande undersökningsmätningar är lakanet inte i närheten   av detta. Om Woolpowers lakan hade testats med den metod som konkurrenten   använt sig av, hade då resultatet visat på någonting annat? Detta öppnar upp   för ett ifrågasättande av den gradering som används på sovsäckslakan idag och   möjligheterna att införa en separat standard för befintliga och framtida   produkter. / With the   help from different standards and articles, tests have been run on a sleeping   bag liner from the company Woolpower, on three different sleeping bags with   different grading for the temperature. Using a thermal manikin, a value for   the total insulation (heat resistance) was defined, and that value was   translated into different scales for temperature, including comfort-,   transition- and extreme temperature limits. All the sleeping bags show a   clear improvement of the insulation value when using the Woolpower liner,   which means that the grading for the temperature limits also changes. A liner   from a competitor company was also evaluated, not only to compare how well   Woolpower´s liner holds up on the market and how well the temperature that   the competing liner put on their product holds up to the value from this   test, but also to open up for a discussion how the grading of the products   used today can be changed to better fit its purpose. In this comparison   between Woolpower and the other company’s liner, Woolpower have a higher   insulation value in all the sleeping bags. These   questions the reliability of the marking on the liners that are used today,   since the results demonstrated in this study are far from what the product   claims. If Woolpowers liner was tested with the same method, would the result   be any different? It opens the possibility to introduce a separate standard   to determine the heat insulation potentials of the liner so that all the   producers follow the same guidelines. / <p>Betyg 2019-07-12</p>

A pasteurização do leite é obrigatória no Brasil e o sistema lento (65ºC/30 minutos) é o mais empregado na fabricação de queijos. Os parâmetros de tempo e temperatura empregados no mundo foram definidos após estudos sobre a resistência térmica do Mycobacterium tuberculosis e da Coxiella burnetti, reconhecidos como os microrganismos patogênicos, não formadores de esporos e que eventualmente podem estar presentes no leite cru, que apresentam a maior resistência térmica. Entretanto, não há estudos sobre a resistência térmica do M. bovis que circula nos bovinos no Brasil. Este estudo propôs-se a avaliar a resistência térmica (65ºC) de cinco espoligotipos de M. bovis, isolados de bovinos abatidos no estado de São Paulo, em leite integral experimentalmente contaminado. Leite UHT foi contaminado com M. bovis e, então, submetido a tratamento térmico em banho-maria a 65ºC por 30 minutos. Cada espoligotipo foi testado 3 vezes. As amostras foram retiradas do banho nos tempos 0 (o momento em que o leite atingiu 65ºC), 5, 10, 15, 20, 25 e 30 correspondendo ao tempo, em minutos, de tratamento térmico. O leite contaminado também foi analisado, para quantificação da carga inicial. O controle do processo envolveu o acompanhamento da temperatura do leite (um tubo com termômetro) e análise das enzimas fosfatase alcalina e peroxidase ao final do tratamento; para tal, amostras de leite cru foram tratadas juntamente com as amostras-teste. Para quantificação, foi realizada a diluição decimal seriada seguida da semeadura em duplicata em meio Stonebrink-Leslie (37ºC/45dias). Os resultados mostraram que foi na fase de aquecimento que ocorreu a maior taxa de morte. Houve diferença de resistência entre os espoligotipos ao processo que simulou a pasteurização lenta e o BR024 foi o mais resistente. Conclui-se que houve diferença da eficácia da pasteurização, de acordo com o espoligotipo testado, mas que os resultados precisam ser melhor investigados. / Milk pasteurization is mandatory in Brazil and the Low Temperature Long Time - LTLT - Pasteurization (62 to 65°C/30 min.) is normally used for cheese making. Permitted parameters were based on the reports of Myconbacterium bovis/tuberculosis inactivation made up to that time. Since then, just a few studies have been done to determine if the M. bovis in circulation nowadays among bovine population still presents the same pattern of inactivation. In this way, this study verified the behavior of recently isolated M. bovis against LTLT Pasteurization parameters reproduced in water bath. M. bovis isolated from bovines slaughtered in São Paulo State, Brazil. When milk reached 65°C the 0 tube was removed and refrigerated while the others taken out after 5, 10, 15, 20, 25 and 30 minutes and cooled. For controlling heat treatment a thermometer was adapted to one tube with 5 ml each of raw milk which were submitted together to heat treatment and used for analysis of peroxidase and alkaline phosphatase enzymes after 30 minutes of heat treatment. Milk samples were submitted to serial decimal dilution in peptone water (0.1%) and inoculated in the Stonebrink-Leslie media. After 45 days at 37°C, colonies were counted and the result expressed in CFU/ml. The results showed that heating phase determined more inactivation than the holding phase. The resentence was different between the spoligotypes that simulated the low pasteurization and BR024 was more resentence. The results enable us to speculate that in the worst scenario of natural contamination of the milk.

A pasteurização do leite é obrigatória no Brasil e o sistema lento (65ºC/30 minutos) é o mais empregado na fabricação de queijos. Os parâmetros de tempo e temperatura empregados no mundo foram definidos após estudos sobre a resistência térmica do Mycobacterium tuberculosis e da Coxiella burnetti, reconhecidos como os microrganismos patogênicos, não formadores de esporos e que eventualmente podem estar presentes no leite cru, que apresentam a maior resistência térmica. Entretanto, não há estudos sobre a resistência térmica do M. bovis que circula nos bovinos no Brasil. Este estudo propôs-se a avaliar a resistência térmica (65ºC) de cinco espoligotipos de M. bovis, isolados de bovinos abatidos no estado de São Paulo, em leite integral experimentalmente contaminado. Leite UHT foi contaminado com M. bovis e, então, submetido a tratamento térmico em banho-maria a 65ºC por 30 minutos. Cada espoligotipo foi testado 3 vezes. As amostras foram retiradas do banho nos tempos 0 (o momento em que o leite atingiu 65ºC), 5, 10, 15, 20, 25 e 30 correspondendo ao tempo, em minutos, de tratamento térmico. O leite contaminado também foi analisado, para quantificação da carga inicial. O controle do processo envolveu o acompanhamento da temperatura do leite (um tubo com termômetro) e análise das enzimas fosfatase alcalina e peroxidase ao final do tratamento; para tal, amostras de leite cru foram tratadas juntamente com as amostras-teste. Para quantificação, foi realizada a diluição decimal seriada seguida da semeadura em duplicata em meio Stonebrink-Leslie (37ºC/45dias). Os resultados mostraram que foi na fase de aquecimento que ocorreu a maior taxa de morte. Houve diferença de resistência entre os espoligotipos ao processo que simulou a pasteurização lenta e o BR024 foi o mais resistente. Conclui-se que houve diferença da eficácia da pasteurização, de acordo com o espoligotipo testado, mas que os resultados precisam ser melhor investigados. / Milk pasteurization is mandatory in Brazil and the Low Temperature Long Time - LTLT - Pasteurization (62 to 65°C/30 min.) is normally used for cheese making. Permitted parameters were based on the reports of Myconbacterium bovis/tuberculosis inactivation made up to that time. Since then, just a few studies have been done to determine if the M. bovis in circulation nowadays among bovine population still presents the same pattern of inactivation. In this way, this study verified the behavior of recently isolated M. bovis against LTLT Pasteurization parameters reproduced in water bath. M. bovis isolated from bovines slaughtered in São Paulo State, Brazil. When milk reached 65°C the 0 tube was removed and refrigerated while the others taken out after 5, 10, 15, 20, 25 and 30 minutes and cooled. For controlling heat treatment a thermometer was adapted to one tube with 5 ml each of raw milk which were submitted together to heat treatment and used for analysis of peroxidase and alkaline phosphatase enzymes after 30 minutes of heat treatment. Milk samples were submitted to serial decimal dilution in peptone water (0.1%) and inoculated in the Stonebrink-Leslie media. After 45 days at 37°C, colonies were counted and the result expressed in CFU/ml. The results showed that heating phase determined more inactivation than the holding phase. The resentence was different between the spoligotypes that simulated the low pasteurization and BR024 was more resentence. The results enable us to speculate that in the worst scenario of natural contamination of the milk.

Les personnes âgées sont souvent victimes de dénutrition pouvant conduire à de multiples dégradations de la santé. La prévention de cet état de dénutrition est une des principales préoccupations des autorités de santé. C’est dans cet objectif que le projet OPTIFEL a conçu de nouveaux produits alimentaires optimisés, afin d’améliorer l’alimentation des personnes âgées, en tenant compte de leurs besoins et souhaits, tout en préservant leur sécurité sanitaire. Bacillus cereus est une bactérie pathogène sporulée capable de se développer dans des conditions variables comme le froid, l’absence d’oxygène, des bas pH ainsi que des matrices alimentaires diverses. Elle est l’une des principales causes de Toxi-Infection Alimentaire Collective (TIAC) surtout en Institut Médico-Sociaux (IMS). Ce travail de thèse avait donc pour objectif de déterminer le comportement de B. cereus à différentes étapes de la vie d’un produit alimentaire. La conservation au froid peut permettre la multiplication de souches psychrotolérantes de B. cereus qui peuvent alors représenter un risque d’infection pour le consommateur. Les conditions anaérobies réduisent la capacité d’adaptation de B. cereus au froid et aux bas pH. La composition de l’aliment et sa préparation influence également le comportement de B. cereus, comme nous l’avons constaté avec un bouillon de carotte dans lequel la présence d’oxygène crée un effet létal pour la bactérie. Certaines souches psychrotolérantes de B. cereus sont capables de produire de la toxine émétique appelée céréulide. Nous avons montré que cette production peut se faire à partir de 8°C et atteindre des concentrations pouvant causer des intoxications à partir de 10°C. S’il est produit dans l’aliment, le cereulide ne serait pas détruit lors de la préparation de l’aliment. Par contre les cellules végétatives de B. cereus sont très thermosensibles et celles qui auraient pu se développer pourront être détruites par un réchauffage du produit avant sa consommation. Ce travail a permis de définir les paramètres importants pour limiter le risque d’infection alimentaire par B. cereus. / Elderlies are often victims of undernutrition which can lead to multiple health damages. Prevention of this state of undernutrition is one of the main concerns of health authorities. With this objective, the OPTIFEL project designed new optimized foodstuffs, to improve foods for elderlies, by taking into account their needs and wishes, while preserving their safety. Bacillus cereus is a spore-forming bacterial pathogen able to grow in various conditions as low temperature, absence of oxygen, low pH and in different types of food. It is one of the main causes of foodborne outbreaks, particularly in socio-medical institutions. The aim of this work was to determine the behavior of B. cereus at different steps of the life of the food product. Cold storage can allow multiplication of psychrotolerant B. cereus strains that can represent a risk of infection for consumers. Anaerobic conditions reduce the adaptation capacity of B. cereus at low temperature and low pH. The composition and the preparation of the food product also influence the behavior of B. cereus, as we showed with carrot broth in which oxygen created a lethal effect for the bacterium. Certain psychrotolerant B. cereus strains are able to produce an emetic toxin named cereulide. We showed that this production starts at 8 °C and can reach at 10 °C concentrations sufficient to cause intoxications. If this toxin is produced in food, it would not be destroyed during the food preparation. In contrast, vegetative cells of B. cereus are very heat-sensitive and those who would have been able to develop could be destroyed by a reheating of the food product before its consumption. This work allowed the identification of important parameters to limit the risk of foodborne disease by B. cereus.

Lightweight refractory products are materials used for the construction of certain parts of industrial furnaces, especially for iron, but also in other sectors where is operated with high temperatures. There are special requests on refractories. The theoretical part contains an overview of used raw materials, production and properties of lightweight refractory products and description of not burnable lightener - chemical additives VUPPOR I and information about previously conducted trials dealing with these topics. The practical part is divided into four parts, which are evaluated by tests which were performed on a refractory clay with chemical additive Vuppor I (samples are lightened and not lightened) - it was primarily a test of sensitivity to drying, density, compressive strength, thermal insulating properties, etc.

This master thesis deals with the development of an expansive anchor material. This material is intended especially for the engineering and power industry where the operating conditions cause thermal stresses of the anchor. In order to meet the requirements for a firm and secure connection of the anchored part, it is necessary to achieve excellent physical-mechanical properties of the developed material such as high compressive strength, high tensile strength based on the base, and resistance to thermal stresses till 200 ° C. All of these processes must be achieved after the ageing of the cement material. Due to the current trend of modern materials that are environmentally friendly, the use of partial replacements for Portland cement is used as a substitute for a primary binder.

Thermal insulating refractories are an integral part of each thermal unit since they reduce its energy consumption. The current phenomenon of saving in both environmental and financial aspects reflects in searching for such possibilities to produce at lower manufacturing and material costs. One of the possible ways is to valorise waste materials. The theoretical part then deals with the division of refractory materials, classification of thermal insulation refractory materials and manufacturing technologies. The experiment is focused on the production of insulating refractory materials made from plastic dough with a possibility of using sawdust and materials made by pressing mixture moist, with a focus on coal bottom ash. Both of these technologies will be tested for the possibility of modification by using mixed clays and of increasing the strength by using clays with lower sintering temperature.