L'attractivité des matériaux polymères issus de ressources renouvelables augmente continuellement en raison de la prise de conscience environnementale de la société. Dans ce contexte, l’acide polylactique (PLA) est un biopolymère qui possède d’indéniables atouts (notamment en termes de rigidité et résistance en traction/flexion) permettant d’envisager des applications à grande échelle, par exemple pour l’automobile. Cependant, les applications durables du PLA sont encore considérablement restreintes à cause de sa fragilité et de sa stabilité thermique limitée. Dans cette thèse, nous nous sommes focalisés sur la conception de nouveaux matériaux à base de PLA pour des applications dans l’automobile, en travaillant notamment sur l’amélioration des propriétés thermiques et mécaniques (notamment la ductilité), y compris sous haute vitesse de déformation. Ainsi, la composition optimale permettant d’atteindre le meilleur compromis entre différentes propriétés (ductilité, résistance et rigidité, résilience, stabilité thermique…), tout en étant composée d’au moins 50% de matériaux biosourcés est déterminée. D'autres stratégies visant à améliorer la capacité ou la vitesse de cristallisation des compositions à base de PLA ont également été étudiées. Dans tous ces développements, une attention particulière est portée sur l’étude des interactions entre structure, propriétés et process. / The interest to use polymeric materials derived from renewable resources increases continuously due to considerably improved environmental awareness and the expected depletion of petrochemical ressources. In this regard, Poly(lactic acid), PLA, is a biopolymer that can respond to the demand for such materials for a wide range of applications, thanks to interesting mechanical properties such as high tensile/flexural strength and rigidity, in particular. However, in many cases, durable applications of PLA have been significantly limited by its inherent brittleness and limited thermal stability. In this dissertation, we focused on the design of new biobased PLA materials for automotive parts subjected to severe loading and environmental conditions, by improving thermal and mechanical properties, including under high strain rate loadings. Thus, the most promising compound is selected as the one that offers the best balance between different properties (ductility, strength and stiffness, impact toughness, good thermal stability…) with a content of bio-sourced polymer in the blend at least equal to 50%. Other strategies to improve crystallinity of PLA-based compounds are also studied. In all those developments, a particular attention is paid to the study of structure-process-properties interactions.

<p>  </p> <p>PhoQP is a two-component system that regulates the transcription of ~5% of the genes of <em>Salmonella enterica</em>. The membrane-bound PhoQ protein is phosphorylated in response to low extracellular Mg²⁺ concentration, acid pH, and a number of antimicrobial peptides. The inorganic phosphate bound to PhoQ is transferred to PhoP, which according to the classical model, acts as a typical transcriptional activator of its target genes. However, Will et al. (doi.org/10.1038/ncomms6270) proposed an alternate “counter-silencing” model, according to which genes in the PhoP regulon that were acquired by <em>Salmonella</em> via horizontal transfer are repressed by the generalized DNA-binding protein H-NS at high [Mg²⁺] and are induced at low [Mg²⁺] because the phosphorylated PhoP displaces the H-NS from the promoters and lifts repression. We evaluated this model by examining the transcriptional regulation of the <em>mgtCBRU-cigR </em>operon, which encodes the virulence protein MgtC and the Mg²⁺ transport protein MgtB and is in the SPI-3 pathogenesis island that has been acquired by <em>Salmonella</em> via horizontal transfer. Our main finding was that in the non-pathogenic strain of <em>S</em>. Typhimurium (LT2), induction of the <em>mgtCBRU-cigR</em> operon by Mg²⁺ limitation requires a functional PhoP protein, regardless of the presence or absence of H-NS. Interestingly, the pathogenic strain of <em>S</em>. Typhimurium (ATCC 14028s) revealed PhoP-independent transcription in the absence of H-NS, but only under inducing conditions. Thus, our results do not support the counter-silencing model and are consistent with the canonical view that PhoP is needed as a transcriptional activator of genes in the PhoP regulon.</p>

The thick and woody shell of the fruit of Adansonia species cannot be explained solely by adaptation to zoochory or hydrochory. Since the trunks of Adansonia possess a thick and fire-resistant bark and wildfires occur regularly in its habitat (savannah), we examined with the African Adanonia digitata and the Australian Adansonia gregorii whether the fruit offers protection against high heat typically experienced in wildfires. Heat-resistance tests were conducted by applying a simple heat test based on known temperature and temperature residence times occurring in savannah fires and complemented by tests to reveal the impact of heat on germination since long-term seed dormancy is known for Adansonia. Germination tests with acid treated and heat treated seeds were performed to establish if heat also increased germination rate as effectively as acid treatments have been found to do. Heat was found to increase germination rate, but not as effectively as treatment with acid, therefore fruits exposed to high temperatures experienced in wildfires may have a better chance of germination than fruits that were not exposed to wildfires. The ability of the investigated fruits to protect seeds from high temperatures suggests that wildfires may have played a role in the evolution of the hard-shell structure typically found in Adansonia.

The thick and woody shell of the fruit of Adansonia species cannot be explained solely by adaptation to zoochory or hydrochory. Since the trunks of Adansonia possess a thick and fire-resistant bark and wildfires occur regularly in its habitat (savannah), we examined with the African Adanonia digitata and the Australian Adansonia gregorii whether the fruit offers protection against high heat typically experienced in wildfires. Heat-resistance tests were conducted by applying a simple heat test based on known temperature and temperature residence times occurring in savannah fires and complemented by tests to reveal the impact of heat on germination since long-term seed dormancy is known for Adansonia. Germination tests with acid treated and heat treated seeds were performed to establish if heat also increased germination rate as effectively as acid treatments have been found to do. Heat was found to increase germination rate, but not as effectively as treatment with acid, therefore fruits exposed to high temperatures experienced in wildfires may have a better chance of germination than fruits that were not exposed to wildfires. The ability of the investigated fruits to protect seeds from high temperatures suggests that wildfires may have played a role in the evolution of the hard-shell structure typically found in Adansonia.

The diploma thesis deals with the development of polymeric repair mortars in two qualitative levels ECONOMY and PREMIUM, designed especially for heavy engineering plants and the energy industry. In order to effectively withstand difficult industrial conditions, the developed materials should meet the highest requirements such as increased chemical and heat resistance, excellent adhesion to the concrete substrate, minimal shrinkage and other physical and mechanical properties. The PREMIUM level is aimed to achieve maximum physical and mechanical properties. Within the economy version, the emphasis is placed not only on very good properties, but also the possibility capability of reducing price of the resulting material. The partial aim of this work is the efficient use of secondary raw materials, mainly based on industrial waste in the form of fillers to the developed polymeric repair mortars.

This diploma thesis discusses fouling processes and mechanisms of industrial heat exchangers, with focus on shell side fouling of heat transfer area by flue gases, and eventually taking fouling into account, or more precisely its modeling and predicting by calculation. Thermal-hydraulic design of heat exchanger is focused mainly on shell side, as flue gases are dominant process medium in terms of fouling and heat transfer. Based on available operational data of evaluated industrial heat exchanger, specific process has been developed to determine by calculation, or more precisely predict change of fouling factor throughout operational period of heat exchanger. Usage and various options of this specific calculation technique are being discussed in conclusion, whether there is a potential to use this technique regarding more complex operational inputs or prediction of fouling process for different operational regime of heat exchanger.

In this thesis an alternative exterior wall construction for a specific building isinvestigated. The focus has been on investigating the material straw as a possiblecomponent in the future project Kulturborgen in Skåne, Sweden.Straw is a bio-based building material which, with a consideration to the climate crisis,has become a viable alternative intended to minimize carbon dioxide emissions from thebuilding sector. Through a compilation of the latest research on the material, theproperties of straw are presented in the theory chapter. Previous studies have shown thepotential of straw to be used as a load-bearing frame in house construction. However, dueto an adaptation to existing blueprints, the focus in this project has been on using straw asonly an insulating material together with load bearing I-joists. By modeling in AutodeskRevit and making calculations on the structure's load bearing capacity and thermalinsulation, a solution on an outer wall has been presented. The work culminates in aproposal for detailed drafts for a specific building that can become the basis for a possiblefurther development. / Halm är en restprodukt från odling av säd och andra grödor och räknas ur miljösynpunkttill ett mer hållbart alternativ än de konventionella byggnadsmaterial som producerasidag. Växtbaserade byggnadsmaterial som halm kan utgöra kolsänkor tack vare sinförmåga att fånga upp koldioxid från atmosfären och med tanke på en störreklimatmedvetenhet har biobaserade material blivit ett aktuellt alternativ ämnat attminimera koldioxidutsläppet från byggbranschen. Tidigare studier visar att halm har godaförutsättningar att användas som ett isolerande material tack vare sin lågavärmekonduktivitet. Halm kan även användas som en självbärande stomme eftersom denhar en hög lastöverföringsgrad. I kombination med en regelkonstruktion av annat materialkan halmen användas enbart som ett isolerande skikt mellan reglarna.Kulturborgen är ett storskaligt byggnadskomplex projekterat som en ringborg med ettöppet torg i mitten. Den byggnad som har studerats i detta examensarbete är enbart en deli komplexet, nämligen ett vandrarhem i två plan. I arbetet undersöks de möjligheter somfinns när en betongväggkonstruktion ersätts med ett biobaserat alternativ samt vilkakonsekvenser det kan få för projekteringen.I detta examensarbete undersöks en alternativ ytterväggskonstruktion för Kulturborgen.Fokus har varit att undersöka materialet halm som en möjlig beståndsdel i det framtidaprojektet Kulturborgen i Skåne, där den ursprungliga planen var att uppföra byggnadenmed prefabricerade betongelement.I en sammanställning av den senaste forskningen om materialet har halmens egenskaperoch tillämpning inom byggbranschen redovisats i ett teorikapitel. Olika metoder för attanvända halm som ett byggnadsmaterial har också tagits upp med avsikt att undersökavilken byggnadsmetod som passar bäst för Kulturborgen.På grund av anpassning till befintliga ritningar på Kulturborgen har användningen avhalm i detta projekt behandlats som enbart ett isoleringsmaterial där halmen är ett 400mm isolerande skikt i kombination med lättreglar med en bärande funktion. Lättreglarvaldes därför att de tack vare sitt I-tvärsnitt har en lägre andel trä än en regel med ettrektangulärt tvärsnitt. Detta gör att lättreglar är materialbesparande och ett lägre U-värdekan erhållas.En modell har tagits fram genom användning av programmet Autodesk Revit.Beräkningar på lättreglar har gjorts för att säkerställa att byggnaden klarar av alla lasterden utsätts för. U-värdesberäkningar utfördes för att kontrollera att vägguppbyggnadensom valdes fick ett U-värde som låg under 0,15 W/m2K, vilket hamnar inom en rimliggräns för en yttervägg. Slutligen har en lösning på en ytterväggskonstruktion presenterats.Arbetet mynnar ut i ett förslag på detaljlösningar för Kulturborgens vandrarhem ochdessa kan ligga till grund för en eventuell vidareutveckling.

Исследовано влияние состояния поверхностей оптических сборок склеенных из стекол ЛК7 и ТФ7 на технические характеристики сборок, склеенных клеем «Бальзамин М», при воздействии различных климатических условий, их деформации, а также на прочность клеевого соединения при равномерном отрыве сборок, изготовленных из стекла К8, склеенных клеем «Бальзамин М». / The influence of the state of the surfaces of optical assemblies glued from LK7 and TF7 glasses on the technical characteristics of assemblies glued with "Balzamin M" glue, under the influence of various climatic conditions, their deformation, as well as on the strength of the adhesive bond with uniform tearing of assemblies made of K8 glass glued with "Balzamin M" glue.

The diploma thesis is partly dedicated to energetic efficiency of buildings and describes possibilities how to evaluate energetic efficiency of buildings in the Czech Republic. We also get to know with distribution of thermal insulators by material base and use in construction. There are also mentioned methods how to determine thermal insulations characteristics of heat insulations, so called heat conductivity coefficient. The last and the crucial chapter of theoretic part is dedicated to thermal-reflective insulations. There are mentioned some of the basic characteristics of insulations, material composition and heat transfer mechanism in their structure as well. Practical part describes measurement of thermal resistance of chosen samples of thermal-reflective insulations per measuring device on the principal of Hot Box method. In the next step was determined emissivity of aluminium foils which forms the surface of chosen samples of thermal-reflective insulations. In the end of thesis are defined possibilities of use thermal-reflective insulations in building structures especially in passive and low-energy buildings in climatic conditions of the Czech Republic.

The subject of this thesis is a design of a newly built guesthouse on a bicycle path in the village Spálené Poříčí. The building is designed in a gently sloping terrain towards the west. The main entrance faces the south. It is an object without a basement and with two above ground floors. The structure of the building is a transverse wall system made of ceramic fittings. Other walls are also made of ceramic fittings. The entire building is based upon the stripe foundations and footings. Pension is covered in the part of the accommodation and in the restaurant part with a gable roof. For the restaurant, a terrace is designed on the west side of the building. In this thesis, static and building equipments are solved. The building is also evaluated in the terms of lighting, thermal, acoustic requirements and the fire safety of building is also solved.