No description available.

No description available.

Roads are subjected to mechanical loads from the traffic as well as deteriorating mechanisms originating from the surrounding environment and climate. The damage arising is particularly severe during the winter season, when for example raveling, pot holes and cracks can emerge on the surfaces of asphaltic roads. These winter related damages are difficult to characterize and predict, partly due to the complexity of the asphalt material and partly since they cannot be linked to one single phenomenon but several, such as the (long term) existence of moisture, frost damage and frost heave, low temperature cracking and the embrittlement of the mastic at low temperatures. Further adding to the complexity is the combination of these phenomena which may accelerate the emergence and evolution of the damage mechanisms. This licentiate research project is mainly focusing on the emergence and development of frost damage in the asphalt layer but will include the effect of other damage mechanisms in its continuation. The goal of the project is to develop a multiscale model able to predict the damage development in an asphalt pavement during a desired period of time, to enhance maintenance predictions as well as pavement design choices. This licentiate thesis is the first part of this project and aims to lay the foundation of the multiscale model. To achieve this, a micromechanical model of frost damage in asphalt mixtures has been developed. This model couples the moisture and mechanical damage happening on the short and long term, caused by the infiltration of moisture and the expansion of water turning into ice during temperature drops. Both possible adhesive damage in the mastic-aggregate interface and cohesive damage in the mastic is included. In addition to the developed micromechanical model, this thesis presents the overall concept for the formulation of the multiscale model as well as discusses about its motivations and advantages. / Vägar utsätts både för mekaniska laster från trafiken som kör på vägen samt för nedbrytande mekanismer härstammande från den omgivande miljön och klimatet. Skadorna som uppstår är särskilt stora under vintern, då till exempel stensläpp, potthål och sprickor kan uppstå på ytan av asfalterade vägar. Dessa vinterrelaterade skador är svåra att karakterisera och förutsäga, delvis på grund av det komplexa beteendet hos asfalt och delvis eftersom de inte härstammar från enbart ett fenomen utan flera, såsom existensen av fukt i asfalten (på lång sikt), frostskador, tjällyft, sprickbildning på grund av låg temperatur samt försprödningen av asfalt som sker vid låga temperaturer. Vidare påverkar dessa skademekanismer varandra vilket kan accelerera skadebildningen och utvecklingen, vilket ytterligare ökar komplexiteten. Detta licentiatforskningsprojekt fokuserar till största delen på uppkomsten och utvecklingen av frostskador men kommer även inkludera effekten av andra skademekanismer i dess fortsättning. Målet med detta forskningsprojekt är att utveckla en multiskalemodell som kan förutspå skadeutvecklingen i en asfaltsväg under en önskad tidsperiod, för att förbättra både underhållsprognoser samt designval. Denna licentiatuppsats är den första delen i detta projekt och syftar till att lägga grunden till multiskalemodellen. För att uppnå detta har en mikromekanisk modell av frostskador i asfalt utvecklats. Denna modell kopplar ihop fuktskadan och den mekaniska skadan som sker både på kort och lång sikt, orsakad av infiltrationen av fukt och expansionen av vatten som omvandlas till is vid sjunkande temperatur. Modellen inkluderar de möjliga skadorna som uppstår i både mastics och gränsskiktet mellan mastics och stenmaterialet. Utöver den utvecklade mikromekaniska modellen presenterar denna uppsats det övergripande konceptet för formuleringen av multiskalemodellen samt diskuterar dess motivering och fördelar. / <p>QC20190515</p>

<p>Aging public infrastructure in North America continues to challenge engineers and scientists to develop repair and rehabilitation strategies that are practical, durable and cost effective. Of specific interest is the state of concrete and concrete repair in buildings and civil engineering infrastructures that are in deteriorating condition. In particular, cracks pose a threat to the durability and ultimately the structural integrity of concrete. Cracks in concrete may form for several reasons, e.g. plastic shrinkage, thermal contraction, mechanical loading or as a result of overloading. Once formed, cracks present a combination of problems to the service life and performance of the structure. Therefore cracks must be repaired for the following reasons: to prevent the ingress of deleterious agents such as water, other liquids, vapour, gas, chemicals and biological agents; to either restore or increase the structural load-bearing capacity of the cracked concrete member; to restore the aesthetic condition of the structure.</p> <p>The effectiveness of two different repair methods, crack injections and cementitious overlays, were examined. Two repair materials, a low viscosity epoxy and polyurethane were injected into the cracks, and a thin polymer-modified cementious overlay was applied on the cracked surface. Two types of cement were used, an ordinary Portland cement and a blended cement with 8% silica fume. The specimen properties were evaluated using non-destructive testing, prior to being subjected to a series of freeze-thaw conditioning regimes. From the experimental program, it was determined that the epoxy injection repair was more effective in restoring the air tightness than the thin overlay. The polyurethane material was unsuccessful. Following the freeze-thaw regimes, an overall improvement of conditions for all three repairs was observed, with the cementitious overlay seeing the greatest improvement in air tightness. These results indicate that the on-going cement hydration mechanism had a greater effect on the performance in comparison to the deleterious effects of the environmental loads.</p> / Master of Applied Science (MASc)

For repairing concrete transportation infrastructure, such as pavements and bridges, much importance is placed on early-age strength gain as this has a major impact on scheduling and opening to traffic. However, the long-term performance and durability of such repair materials are often not satisfactory, thus resulting in future repairs. This research project focuses on the evaluation of the durability of various rapid-setting cementitious materials. The binders studied in this project include calcium aluminate cement (CAC), calcium sulfoaluminate cement (CSA), Type III portland cement, alkali-activated fly ash (AAFA) , and various prepackaged concrete materials. In addition, selected CAC and CSA mixtures were further modified with the use of a styrene-butadiene latex. The durability aspects studied include freezing-and-thawing damage and the implications of air entrainment in these systems, alkali-silica reaction, sulfate attack, and permeability of the concrete matrix and potential corrosion. / text

Thermal resistance per unit thickness for Vacuum Insulation Panel (VIP) is 5 to 10 times higher than conventional insulation materials. This makes VIP an attractive option for retrofitting exterior building envelopes. Insulation can be added in an exterior wall either on the interior side, exterior side or in the available stud cavity. VIP has high vapor diffusion resistance factor and could lead to moisture management risk in the wall layers because of the steep temperature gradient in the wall generated due to very high thermal resistance of VIP. VIP is a relatively new insulation material for building envelope construction, thus the hygrothermal or moisture management performance of VIP-insulated exterior building envelopes need to be critically analyzed before its application. This study aims to evaluate the moisture management risk associated with wood-frame stucco-cladded exterior walls retrofitted with VIP using a 2-D hygrothermal simulation tool WUFI-2D. Eight North American locations were considered, based on Moisture Index (MI) which varied between 0.13 and 1.17, and two different indoor hygrothermal loading conditions as prescribed by the ASHRAE 160P and EN 13788, respectively. The outputs from hygrothermal simulations (water content, relative humidity and temperature) were critically analysed and expressed further using freeze-thaw cycles and RHT indices. The results show that the appropriately designed VIP retrofitted walls can have superior moisture management performance as compared to conventional stucco-cladded wall. / Graduate

Un nouvel contexte de sécurité en Europe a fait place à l’ère bipolaire au cours des années 1990. La chute du communisme découvre une Europe scindée entre les pays occidentaux et les pays de l’Europe orientale, une région positionnée au carrefour des civilisations, tributaire encore aux défis, dangers et risques qui accompagnent la chute de l’empire soviétique. Au début des années 1990, un nouveau paradigme de sécurité, surnommé le « paradigme de sécurité gelé » remplace l’ancien paradigme de la bipolarité, spécifique à la guerre froide. Le manque de coopération entre les pays de la région devient la principale caractéristique de l’époque, au début et lors du moment unipolaire. Le tableau de la sécurité régionale nous montre deux camps avec des conceptions apparemment irrémédiables : d’un part, les pays appartenant à l’ancien système communiste, chacun avec les propres craintes vis-à-vis d’un possible revirement de la Russie et chacun avec une forte orientation pro-occidentale. D’autre part il existe une Russie désireuse de rétablir la sphère d’influence perdue et de regagner la gloire impériale, en utilisant de plus en plus une nouvelle méthode de coercition, l’arme énergétique. Dans cette équation de pouvoir, il est intéressant de poursuivre l’évolution et le rôle de la Roumanie, un pays de faille, appartenant par la langue et par la culture à la civilisation occidentale et par religion à la civilisation orthodoxe. En définitive, par son positionnement stratégique, et par sa volonté de retrouver son identité européenne perdue lors du communisme, la Roumanie deviendra l’une des importants piliers de la défense otaniene dans cette part du continent. / A new security environment in Europe replaced the bipolarity era since the ‘90th. The fall of communism reveals a Europe divided between Western countries and the Eastern Europe, region located at the crossroads of civilizations, tributary to the challenge, risks and hazards accompanying the Soviet collapse. Early ’90th, a new security paradigm, the “paradigm of freeze security” replaces the old one of bipolarity during the Cold War. The lack of cooperation among the countries in the region is the main characteristic of the period, from the beginning and during unipolar moment. The picture of regional security show us two camps having apparently irremediable ideology: on the one hand, countries belonging to the former Soviet empire, each of them having their own concern about a possible sudden change of Russia, but with a strong Western orientation, and on the other hand, the existing Russian empire willing to reestablish a sphere of influence and to regain lost imperial glory, using increasingly a more and new coercion weapon – the energy weapon. In this equation of power, is interesting to observe the evolution and Romania role, a buffer security zone, by the language and culture belonging of Western civilization and by religion of Orthodox civilization. Ultimately, by its strategic position and desire to find again, its European identity, lost during Communism era, Romania will become one of the important pillars of NATO defense, in this part of the continent.

Doctor of Philosophy / Department of Plant Pathology / Megan Kennelly / Large patch, caused by the fungus Rhizoctonia solani anastomosis group (AG) 2-2 LP, is the most common and severe disease of zoysiagrass (Zoysia spp). Despite the importance of this disease, few studies have examined pathogen biology, cultivar susceptibility, cultural controls, and chemical controls. The objectives of this dissertation were: (1) Characterize large patch isolates based on anastomosis pairing, in-vitro mycelial growth rates, nuclear counts, virulence, PCR, and amplified fragment length polymorphism (AFLP); (2) Determine the effects of cultivation (aerification, verticutting, and sand topdressing) on disease severity; (3) Evaluate different fall and spring applications of the fungicides flutolanil, azoxystrobin, and triticonazole; (4) Evaluate the susceptibility of fifteen new zoysiagrass germplasm lines from parental crosses including Z. japonica, Z. matrella, and Z. pacifica. All the R. solani isolates from large patch-infected zoysiagrass from Kansas belonged to AG 2-2 LP. Variations were observed among the isolates in their average number of nuclei per cell, mycelial growth rates and virulence. There was also variation in the amplified fragment length polymorphism (AFLP) DNA fingerprints, suggesting possible underlying genetic differences of biological significance among members of AG 2-2 LP. Cultivation did not affect soil moisture or temperature. Cultivation also did not reduce patch sizes, nor influence turf recovery rate from large patch. From 2009 to 2011, spring and fall N fertility was consistently associated with lower percentages of diseased turf in both cultivated and non-cultivated plots at Manhattan and Haysville. In general, two fall applications of fungicide did not reduce disease compared to one fall application. Fungicides applied in the fall when thatch temperatures ranged from 17.8oC to 23.2oC reduced disease compared to untreated controls. Early spring applications reduced disease compared to later spring applications. In germplasm screening studies, all progeny had similar disease levels compared to Meyer in the growth chamber, but only 6 consistently had disease levels as low as Meyer in the field. Growth chamber results did not correlate to field results.

L’objectif général de cette thèse a été d’étudier le potentiel de billes à base de molécules d’α-cyclodextrine et d’huile de soja, pour l’administration orale de principes actifs peu solubles dans l’eau.Nous avons tout d’abord vérifié qu’il était possible d’encapsuler dans les billes des molécules actives (la progestérone et l’indométacine) autres que les rétinoïdes et le diazépam, avec une teneur élevée et un rendement de fabrication satisfaisant. L’étude du comportement des billes nues lyophilisées, en termes de stabilité et de libération dans des milieux digestifs simulés, nous a permis de proposer un mécanisme de libération de la molécule encapsulée qui se déroule en plusieurs étapes: i) hydratation des billes, ii) dissolution de la matrice hydrophile d’α-cyclodextrine, iii) libération de gouttelettes d’huile contenant le principe actif puis de la fraction dissoute dans l’huile par un phénomène de partage, iiii) fragmentation des billes fragilisées et libération totale de l’huile. La présence de sels biliaires dans le milieu, accélère à la fois la libération et la quantité dissoute, en fragilisant les billes et en réduisant la valeur du coefficient de partage du principe actif entre l’huile et le milieu digestif. Nous avons montré in vitro et in vivo qu’il est possible de moduler la libération d’un principe actif à partir d’une même formulation de départ, en jouant sur l’organisation du système (émulsion sèche, billes nues, billes coquées par un nouvel ajout d’α-cyclodextrine sur les billes nues). Les études in vivo chez le rat ont révélé que l’émulsion sèche se comporte comme une forme à libération immédiate, les billes coquées comme une forme à libération prolongée et les billes nues comme une forme à libération intermédiaire. Enfin, la libération du principe actif encapsulé peut également être modulée en modifiant le mode de séchage des billes. Comparativement à la lyophilisation, le séchage à l’étuve modifie les propriétés des billes en augmentant leur résistance dans les milieux digestifs simulés et prolonge la libération de la molécule encapsulée. / The general aim of this thesis was the study of the potential of beads, made of α-cyclodextrin and soybean oil, for the oral delivery of poorly water soluble drugs. We have first verified that it was possible to encapsulate in beads, active molecules (progesterone and indomethacin), other than retinoid and diazepam, with a high drug loading and a satisfying yied. The study of the behaviour of freeze-dried naked beads, in terms of stability and drug release in simulated gastro-intestinal fluids, allowed to propose a mechanism for the release of the encapsulated drug, involving several steps: i) hydration of the freeze-dried beads, ii) dissolution of α-CD hydrophilic matrix, iii) release of oily droplets containing the active drug and then of the fraction of drug dissolved in oil, following a partition phenomenon, iiii) fragmentation of the weakened beads and at last the total release of oil. The presence of bile salts in the medium accelerates both the release and the dissolved amount, by weakening the beads and reducing the partition coefficient value of the active molecule between oil and digestive medium.We have shown in vitro as well as in vivo that it is possible to modulate the release of a model drug from the same initial formulation, according to the degree of organization of the system (dry emulsion, naked beads, coated beads obtained by an additional amount of α-cyclodextrine to the preformed naked beads). In vivo studies in rats have highlighted that dry emulsion behaves as a fast release formulation, the coated beads as a sustained release formulation and the naked beads as an intermediate one. Finally, the release of the encapsulated drug can also be modulated by modifying the drying method of the beads. Compared to freeze-drying, oven-drying modifies the properties of the beads by increasing their resistance in simulated gastro-intestinal fluids and sustaining the release of the encapsulated drug.

Óleos essenciais (OEs) constituem misturas complexas de várias moléculas voláteis hidrofóbicas produzidas pelo metabolismo secundário de plantas. Eles são empregados em diversos setores industriais, como por exemplo, o farmacêutico, alimentício, cosmético, agricultura e pecuária, em virtude de suas comprovadas ações bactericida, virucida, fungicida, antiparasitária, inseticida, analgésica, sedativa, anti-inflamatória, espasmolitica e anestésica local. Também têm sido utilizados na proteção de alimentos (como antioxidantes e conservantes), e incorporados em embalagens ativas. Os OEs podem apresentar problemas de instabilidade quando expostos ao calor, umidade, oxigênio e luminosidade. A reduzida solubilidade em água e sua elevada volatilidade são outras limitações para seu uso. A microencapsulação e nanoencapsulação dos OEs são estratégias viáveis e eficientes à proteção e modulação da liberação dos compostos bioativos, promovendo o aumento da estabilidade físico-química, proteção contra fatores ambientais, redução da volatilidade, aumento da solubilidade, biodisponibilidade, atividade biológica, redução da toxicidade, entre outros. A encapsulação em carreadores lipídicos micro e nanoestruturados tem recebido significativa atenção nos setores farmacêutico e alimentício, em face de várias vantagens, como baixa toxicidade, facilidade de escalonamento, baixo custo de produção e capacidade de encapsular compostos hidrofílicos e lipofílicos. Este trabalho teve como objetivo estudar a formação e secagem de sistemas lipídicos micro e/ou nanoestruturados contendo óleo essencial de Lippia sidoides, empregando diferentes processos tecnológicos e avaliar a influência destes nas propriedades apresentadas pelo produto líquido e seco obtido (propriedades físico-químicas, estabilidade, atividade antimicrobiana e retenção do timol, composto ativo majoritário no OE). Os resultados mostraram que a composição das formulações, as condições e o processo de secagem tiveram efeitos significativos nas propriedades físico-químicas e na estabilidade do produto, além de influenciarem também a retenção de timol. Este trabalho permitiu obter informações relevantes sobre os processos de secagem das formulações lipídicas por spray drying e liofilização e também sobre as características apresentadas pelos pós obtidos / Essential oils (EOs) are complex mixtures of various volatile molecules (hydrophobic) produced by the plants secondary metabolism. Essential oils have high importance in various industrial sectors, such as pharmaceutical, food, cosmetic, health, agriculture and livestock; mainly due to its proved biological activity as bactericidal, virucidal, fungicidal, antiparasitic, insecticidal, analgesic, sedative, anti-inflammatory, spasmolytic and local anesthetic activities. Essential oils have also been used in food protection (as antioxidants and preservatives), and embedded in active food packaging. It is also characteristic of EOs present problems of instability when exposed to heat, moisture, oxygen and light. The reduced water solubility and high volatility are another limitation for the use of EOs. The micro and nanoencapsulation technologies of EOs arises as a viable and effective solution, increasing the product physicochemical stability, furnishing protection against environmental factors, reducing volatility, modulate the release, increasing bioavailability, reducing toxicity, among others. Encapsulation in lipid carriers has received significant attention in the pharmaceutical and food sectors, mainly due to the several attributed advantages such as low toxicity, capability to encapsulate hydrophilic and lipophilic compounds, low production costs and easy scale up. The objective of this work was to study the formation and drying of micro and/or nanostructured lipid systems loaded with essential oil of Lippia sidoides using different technological processes and to evaluate their influence on the properties presented by the liquid and dry product obtained (physicochemical properties, stability, antimicrobial activity and retention of thymol, major active compound in EO). The results showed that the composition of the formulations, the conditions and the drying process had significant effects on the physicochemical properties and the stability of the product, besides also influencing the retention of thymol. This work allowed to obtain relevant information on the drying processes of the lipid formulations by spray and freeze drying and also on the characteristics presented by the obtained powders