Hot melt adhesives (HMA) are a class of adhesives that, unlike solvent-or waterborne counterparts, do not contain organic solvents or other carriers, and are produced and subsequently applied in a molten state. The main components of HMA are polymers, tackifying resins, and a plasticiser. HMA offer a more environmentally friendly option of adhesive materials.  This study was undertaken to investigate the performance of plasticisers based on renewable resources in HMA. Historically, mineral oil-based plasticisers have been used with great success in HMA formulations, offering a performance benchmark. This work selected suitable alternatives from renewable resources, ranging from fully renewable to fully conventional compositions. During the production stage, the compatibility of such plasticisers with the rest of the HMA formulation was studied while rheological methods were used to investigate the impact of different plasticisers on the properties of the final HMA. Adhesive properties were also assessed by loop tack and peel tests on polyethylene terephthalate (PET) and stainless steel (SS) substrates.   It was shown that some of the studied materials from renewable resources could offer a suitable component in the design of a biobased plasticiser, whose performance matched conventional plasticisers, while the ratio of the biobased fraction was up to 70 % and possibly even higher. The findings of this work show the potential of biobased alternatives in making HMA with a higher degree of sustainability. / Smältlim är en klass av lim som, till skillnad från lösningsmedels-eller vattenburna motsvarigheter, inte innehåller organiska lösningsmedel eller andra bärare, och som produceras och appliceras därefter i smält tillstånd. Huvudkomponenterna i HMA är polymerer, klibbgivande hartser och en mjukgörare. smältlim erbjuder ett mer miljövänligt alternativ för limmaterial. Denna studie genomfördes för att undersöka prestandan hos mjukgörare baserade på förnybara resurser i HMA. Historiskt har mineraloljebaserade mjukgörare använts med stor framgång i HMA-formuleringar, vilket ger ett prestandariktmärke. Lämpliga alternativ valdes ut från förnybara resurser, allt från helt förnybara till helt konventionella kompositioner. Under produktionsstadiet studerades kompatibiliteten av sådana mjukgörare med resten av smältlimsformuleringen medan reologiska metoder användes för att undersöka olika mjukgörares inverkan på egenskaperna hos det slutliga limmet. Vidhäftningsegenskaperna utvärderades också genom loop tack test och peel test på polyetylentereftalat (PET) och rostfritt stål (SS) substrat. Det visades att en del av de studerade materialen från förnybara resurser kunde erbjuda en lämplig komponent i designen av en biobaserad mjukgörare, vars prestanda matchade konventionella mjukgörare, medan förhållandet mellan den biobaserade fraktionen var upp till 70 % och möjligen ännu högre. Resultaten av detta arbete visar potentialen hos biobaserade alternativ för att göra HMA med en högre grad av hållbarhet.

22 pp. / Private horse ownership is not for everyone; owning a horse comes with many responsibilities. You must properly house and care for the horse. This care includes the horse's feeding, health care, and hoof care, but these are only part of the equation. You must also provide housing facilities, transportation, and riding equipment. This booklet is an introductory guide to the proper care and cost of owning and maintaining a pleasure horse in Arizona. We discuss how to feed and care for a horse as well as all of the associated costs to expect whether you board your horse or house and care for it privately. The publication has two major sections: (1)maintaining and caring for a horse, and (2) budgeting for the costs of ownership and care. There is also an introduction to getting started and a list of additional resources at the end.

A aplicação de pintura de ligação entre camadas asfálticas é prática comum em obras de pavimentos novos ou restaurações, sendo importante para garantir a aderência entre as camadas. Esse tratamento da interface geralmente é feito com emulsão asfáltica, que faz com que a estrutura do pavimento trabalhe como um sistema monolítico, evitando problemas de trincamento precoce por fadiga, ou escorregamentos. Esse trabalho tem como objetivo estudar a variabilidade de comportamento dos revestimentos asfálticos quanto à aderência na interface, tendo em vista a taxa aplicada de pintura de ligação, o tipo de emulsão (convencional ou modificada por polímero), a superfície de contato entre as camadas e a presença, ou não, de um sistema anti-reflexão de trincas (geotêxtil e grelha de fibra de vidro). A aderência foi medida por meio do ensaio de cisalhamento direto Leutner, em amostras produzidas em laboratório e extraídas de pista. Foram produzidas placas com dupla camada de revestimento asfáltico, sendo a camada superior um CBUQ (Concreto Betuminoso Usinado a Quente) e a inferior, ora SAMI (Stress Absorbing Membrane Interlayer), ora CBUQ, variando a taxa de aplicação de pintura de ligação na interface (0,0; 0,25; 0,5 e 0,75 L/m2) e o tipo de emulsão aplicada (RR-1C, RR- 1C-E e RR-2C-E), além de testar duas diferentes dimensões para as amostras cilíndricas ensaiadas (100 e 150 mm de diâmetro). Os ensaios de cisalhamento direto foram feitos com carregamento monotônico, à taxa de deslocamento de 50mm/min e à temperatura de 20ºC. Realizou-se o mesmo ensaio também com velocidade de 1 mm/min para avaliar a influência desse parâmetro nos resultados de aderência para as três emulsões testadas. As amostras de pista, com 100 mm de diâmetro, foram retiradas de um trecho experimental na Rodovia Ayrton Senna (SP- 070), do km 38,000 ao 39,500. Os resultados do teste de aderência em laboratório demonstraram influência do tipo de emulsão, da presença de geotêxtil/grelha na interface, do diâmetro da amostra, da textura superficial entre camadas e da velocidade de ensaio nos valores de tensão cisalhante máxima e na taxa ótima de aplicação de emulsão. Os valores de taxa ótima de pintura de ligação foram maiores quando na presença de geotêxtil na interface e para superfícies de contato com maior macrotextura. Quanto à aderência, as amostras com grelha não apresentaram diferença significativa comparadas ao uso de interface somente com pintura de ligação, enquanto as amostras com geotêxtil na interface resultaram em valores bem 8 inferiores de tensão cisalhante máxima. Para ensaios com diferentes tipos de pintura de ligação, as amostras com emulsão modificada nem sempre apresentaram melhores resultados em relação às amostras com emulsão convencional. / Asphalt tack coat is commonly applied at the interface between asphalt layers during new pavement construction or overlay to ensure proper bond between the layers. This treatment at the interface, usually done with asphalt emulsion, allows the pavement structures to function as a monolithic system, avoiding problems like premature fatigue cracking, or slippage. This study aims to evaluate: (i) the influence of the tack coat type (neat or polymer modified asphalt emulsion), (ii) the application rate, (iii) the surface type, and (iv) the presence, or not, of an anti-reflective cracking interlayer (geotextile and fiber glass grid), in the adhesion properties between asphalt concrete layers. The adhesion between layers was tested through the Leutner shear test in laboratory and field samples. A double-layer system was produced with HMA as the top layer and SAMI (Stress Absorbing Membrane Interlayer), or HMA, as the bottom layer, varying the tack coat type (RR-1C, RR-1C-E e RR-2C-E), the application rate at the interface (0,0; 0,25; 0,50 and 0,75 L/m²) and the samples diameter (100 and 150 mm diameter). It was used the standard shear displacement rate of 50 mm/min, and the test temperature was set at 20°C. The same procedure was run with a displacement rate of 1 mm/min to evaluate its influence on the adhesion of three asphalt emulsions used as the tack coat. An experimental test section was constructed on Rodovia Ayrton Senna (SP-070), from km 38,000 to 39,500, and core samples (100 mm diameter) were extracted. The results of maximum shear stress demonstrate the influence of the tack coat type, the surface type, the sample diameter, the test displacement rate and the presence of a geotextile/grid on the adhesion at the interface between the asphalt layers,. Samples with grid at the interface presented similar results when compared with the samples with only tack coat at the interface. Samples with geotextile, however, presented significant lower values of maximum shear stress. The Leutner results showed that not always the modified asphalt emulsions present higher shear strength when compared to the neat asphalt emulsions.

A aplicação de pintura de ligação entre camadas asfálticas é prática comum em obras de pavimentos novos ou restaurações, sendo importante para garantir a aderência entre as camadas. Esse tratamento da interface geralmente é feito com emulsão asfáltica, que faz com que a estrutura do pavimento trabalhe como um sistema monolítico, evitando problemas de trincamento precoce por fadiga, ou escorregamentos. Esse trabalho tem como objetivo estudar a variabilidade de comportamento dos revestimentos asfálticos quanto à aderência na interface, tendo em vista a taxa aplicada de pintura de ligação, o tipo de emulsão (convencional ou modificada por polímero), a superfície de contato entre as camadas e a presença, ou não, de um sistema anti-reflexão de trincas (geotêxtil e grelha de fibra de vidro). A aderência foi medida por meio do ensaio de cisalhamento direto Leutner, em amostras produzidas em laboratório e extraídas de pista. Foram produzidas placas com dupla camada de revestimento asfáltico, sendo a camada superior um CBUQ (Concreto Betuminoso Usinado a Quente) e a inferior, ora SAMI (Stress Absorbing Membrane Interlayer), ora CBUQ, variando a taxa de aplicação de pintura de ligação na interface (0,0; 0,25; 0,5 e 0,75 L/m2) e o tipo de emulsão aplicada (RR-1C, RR- 1C-E e RR-2C-E), além de testar duas diferentes dimensões para as amostras cilíndricas ensaiadas (100 e 150 mm de diâmetro). Os ensaios de cisalhamento direto foram feitos com carregamento monotônico, à taxa de deslocamento de 50mm/min e à temperatura de 20ºC. Realizou-se o mesmo ensaio também com velocidade de 1 mm/min para avaliar a influência desse parâmetro nos resultados de aderência para as três emulsões testadas. As amostras de pista, com 100 mm de diâmetro, foram retiradas de um trecho experimental na Rodovia Ayrton Senna (SP- 070), do km 38,000 ao 39,500. Os resultados do teste de aderência em laboratório demonstraram influência do tipo de emulsão, da presença de geotêxtil/grelha na interface, do diâmetro da amostra, da textura superficial entre camadas e da velocidade de ensaio nos valores de tensão cisalhante máxima e na taxa ótima de aplicação de emulsão. Os valores de taxa ótima de pintura de ligação foram maiores quando na presença de geotêxtil na interface e para superfícies de contato com maior macrotextura. Quanto à aderência, as amostras com grelha não apresentaram diferença significativa comparadas ao uso de interface somente com pintura de ligação, enquanto as amostras com geotêxtil na interface resultaram em valores bem 8 inferiores de tensão cisalhante máxima. Para ensaios com diferentes tipos de pintura de ligação, as amostras com emulsão modificada nem sempre apresentaram melhores resultados em relação às amostras com emulsão convencional. / Asphalt tack coat is commonly applied at the interface between asphalt layers during new pavement construction or overlay to ensure proper bond between the layers. This treatment at the interface, usually done with asphalt emulsion, allows the pavement structures to function as a monolithic system, avoiding problems like premature fatigue cracking, or slippage. This study aims to evaluate: (i) the influence of the tack coat type (neat or polymer modified asphalt emulsion), (ii) the application rate, (iii) the surface type, and (iv) the presence, or not, of an anti-reflective cracking interlayer (geotextile and fiber glass grid), in the adhesion properties between asphalt concrete layers. The adhesion between layers was tested through the Leutner shear test in laboratory and field samples. A double-layer system was produced with HMA as the top layer and SAMI (Stress Absorbing Membrane Interlayer), or HMA, as the bottom layer, varying the tack coat type (RR-1C, RR-1C-E e RR-2C-E), the application rate at the interface (0,0; 0,25; 0,50 and 0,75 L/m²) and the samples diameter (100 and 150 mm diameter). It was used the standard shear displacement rate of 50 mm/min, and the test temperature was set at 20°C. The same procedure was run with a displacement rate of 1 mm/min to evaluate its influence on the adhesion of three asphalt emulsions used as the tack coat. An experimental test section was constructed on Rodovia Ayrton Senna (SP-070), from km 38,000 to 39,500, and core samples (100 mm diameter) were extracted. The results of maximum shear stress demonstrate the influence of the tack coat type, the surface type, the sample diameter, the test displacement rate and the presence of a geotextile/grid on the adhesion at the interface between the asphalt layers,. Samples with grid at the interface presented similar results when compared with the samples with only tack coat at the interface. Samples with geotextile, however, presented significant lower values of maximum shear stress. The Leutner results showed that not always the modified asphalt emulsions present higher shear strength when compared to the neat asphalt emulsions.

Spray drying is a widely used unit operation for producing particulate products directly from a liquid feed. Important processes that occur inside the spray dryer are droplet formation, droplet drying and interactions between droplets and recycled fines. Various studies have looked at the first two processes, but the latter phenomenon has received less attention. Literature on droplet-particle interaction which aims at quantitatively describing agglomeration in spray drying is scarce and mainly qualitative. For product quality the formation of agglomerates is often desirable. This thesis models and investigates the collisions of individual particles with single droplets. The surface tack of drying droplets has been identified as an important variable for the formation of agglomerates. In this thesis a novel method for measuring tack from the liquid phase has been further improved. The improvements are a more accurate load measurement, an automated control of the tack probe and an improved layout of the sample holder and probe. The key feature of the device is its ability to measure tack of drying droplets, whereas other devices measure tack by wetting a powder. Using our method the tack of a commonly spray dried product, yeast extract, has been measured. From these experiments it was found that with decreasing average moisture content the surface tack increases to a maximum. Below a critical average moisture content the surface of the droplet is dry and the tack rapidly decreases upon further drying. Another important parameter in determining the degree of agglomeration is the degree of penetration. If the particle penetrates the droplet too deeply, the agglomerate structure becomes too dense. To predict the penetration depth, a non-dimensional model has been developed. It describes the penetration of a particle into a liquid droplet during a head-on collision. It is based on a force balance and incorporates surface tension force, viscous force and capillary pressure force. The important parameters determining the collision outcome are the contact angle, the size of the droplet relative to the particle, the Reynolds and Weber numbers. For each contact angle an equilibrium penetration position exists, at this point the surface tension force vector is perpendicular to the penetration direction. Five different penetrations regimes are identified. At low Reynolds numbers, viscous forces dominate and the particle asymptotically travels towards the equilibrium position. Reducing the viscous drag force by increasing the Reynolds number results in initially overshooting the equilibrium position, but the surface tension force pulls the particle back, to attain the equilibrium in an oscillating motion. At even higher Reynolds numbers the particle fully penetrates the droplet, and reaches the centre of the droplet for even higher values for the Reynolds number. The ejection regime is found at high Reynolds number and low Weber numbers and the liquid should be non-wetting. Using the regime maps one is able to identify in which region a spray dryer is operating. Although the full penetration regimes are useful for capturing fines, it should be avoided when agglomeration is desired. The ejection regime should be avoided as well. To validate the model, impact experiments were carried out by dropping glass spheres on the surface of different liquids. These validation experiments were the first attempt to experimentally validate the collision of a single particle with a liquid surface. Besides yeast extract, which has non-Newtonian rheological properties, silicone oils with constant viscosities of 100 mPa•s and 1 Pa•s have been tested. The penetration over time for different impact velocities was determined by analysing high speed camera recordings. The typical penetration times ranged from 0.2 s to 2 s. To obtain accurate location data was recorded at frame rates up to 38 000 frames per second. Glass spheres, with a size of 2 mm were used to allow the visual tracking. Modelling the impacts showed that the model consistently predicted faster penetration times than were observed experimentally. The relative difference increased with increasing viscosity. A parameter fitting exercise showed that better agreement could be obtained by using a higher viscosity and a higher contact angle in the model. With this knowledge the most likely factor influencing the model-experiment mismatch was identified as being the dynamics of wetting of the particle surface. It was also found that using the dynamic contact angle in the model would improve its results. The non-Newtonian characteristics of the yeast extract resulted in the particle rebound and the formation of an air cavity upon impact. The tack measurement technique and penetration model presented in this thesis will be useful tools for the design of spray dryers. Recommendations are made for further model improvement. The experimental validation is the first attempt to validate the presented model. Future improvements are recommended and suggestions are presented.

The theoretical part of the diploma thesis describes basic composition of the rubber stock and the methods used for its processing. It summarizes current knowledge about building tack. The experimental part of the thesis deals with the methods of accelerated aging proposal, which have been used for testing UV radiation, ozone, temperature and humidity effect on tack. After bringing two samples together by defined pressure, the tack was determined by T-peel test. Surfaces of the samples were characterized by scanning electron microscopy and infrared spectroscopy. The aditivation of the rubber stock was done in order to compare the effects of tackifiers on accelerated aging.

Doctor of Philosophy / Department of Civil Engineering / Mustaque Hossain / A Superpave asphalt mixture with 4.75-mm nominal maximum aggregate size (NMAS) is a promising, low-cost pavement preservation treatment for agencies such as the Kansas Department of Transportation (KDOT). The objective of this research study is to develop an optimized 4.75-mm NMAS Superpave mixture in Kansas. In addition, the study evaluated the residual tack coat application rate for the 4.75-mm NMAS mix overlay. Two, hot-in-place recycling (HIPR) projects in Kansas, on US-160 and K-25, were overlaid with a 15- to 19-mm thick layer of 4.75-mm NMAS Superpave mixture in 2007. The field tack coat application rate was measured during construction. Cores were collected from each test section for Hamburg wheel tracking device (HWTD) and laboratory bond tests performed after construction and after one year in service. Test results showed no significant effect of the tack coat application rate on the rutting performance of rehabilitated pavements. The number of wheel passes to rutting failure observed during the HWTD test was dependent on the aggregate source as well as on in-place density of the cores. Laboratory pull-off tests showed that most cores were fully bonded at the interface of the 4.75-mm NMAS overlay and the HIPR layer, regardless of the tack application rate. The failure mode during pull-off tests at the HMA interface was highly dependent on the aggregate source and mix design of the existing layer material. This study also confirmed that overlay construction with a high tack coat application rate may result in bond failure at the HMA interface. Twelve different 4.75-mm NMAS mix designs were developed using materials from the aforementioned but two binder grades and three different percentages of natural (river) sand. Laboratory performance tests were conducted to assess mixture performance. Results show that rutting and moisture damage potential in the laboratory depend on aggregate type irrespective of binder grade. Anti-stripping agent affects moisture sensitivity test results. Fatigue performance is significantly influenced by river sand content and binder grade. Finally, an optimized 4.75-mm NMAS mixture design was developed and verified based on statistical analysis of performance data.

Adhesion between different objects is happening everywhere. Without it, simple procedures like walking or holding something in a hand or attaching a postage stamp would be impossible. The life itself depends on adhesion on all levels, starting from the interactions between the living cells. Adhesion between two substrates is a complex phenomenon, which at present is still not well understood. There are several factors determining the strength of adhesion: (i) molecular interactions at interface, (ii) mechanical properties of adhesive, and (iii) area of contact between adhesive and probing surface. Two surfaces are tacky when they possess the right balance between these factors. Controlling the adhesion of materials is important in many fields ranging from industrial purposes to biomedical applications and everyday usage. There is a demand for “smart” materials with integrated functionalities that make them responsive, switchable, biocompatible, anti-bacterial, more energy efficient, or autonomous. In particular, materials for such cutting-edge applications like cell culture, drug delivery, tissue engineering, biosensors, anti/biofouling, microfluidics, climbing robots, sport equipment and many others require adjustable/tuneable adhesive properties. Many efforts were directed towards fabrication of materials with either weak or strong adhesion depending on the field of application. However, design of “smart” surfaces with reversibly switchable/controllable adhesion is still a highly challenging task. Therefore, the thesis aims on design of smart polymeric materials with responsive / adaptive adhesion properties. For this, fabrication and investigation of two types of switchable polymer layers based on stimuli-responsive polymer brushes will be performed. The first group is dealing with thermoresponsive polymer brushes: poly-(N-isopropylacrylamide) and two types of biocompatible polyethylene glycol-based systems. These polymer layers undergo phase transition below and above LCST between hydrophilic and hydrophobic states. The second part of the work is related to solvent-responsive comb-like and block copolymer brushes consisted of hydrophilic PEG and hydrophobic PDMS biocompatible and biodegradable polymers.

Adhesion between different objects is happening everywhere. Without it, simple procedures like walking or holding something in a hand or attaching a postage stamp would be impossible. The life itself depends on adhesion on all levels, starting from the interactions between the living cells. Adhesion between two substrates is a complex phenomenon, which at present is still not well understood. There are several factors determining the strength of adhesion: (i) molecular interactions at interface, (ii) mechanical properties of adhesive, and (iii) area of contact between adhesive and probing surface. Two surfaces are tacky when they possess the right balance between these factors. Controlling the adhesion of materials is important in many fields ranging from industrial purposes to biomedical applications and everyday usage. There is a demand for “smart” materials with integrated functionalities that make them responsive, switchable, biocompatible, anti-bacterial, more energy efficient, or autonomous. In particular, materials for such cutting-edge applications like cell culture, drug delivery, tissue engineering, biosensors, anti/biofouling, microfluidics, climbing robots, sport equipment and many others require adjustable/tuneable adhesive properties. Many efforts were directed towards fabrication of materials with either weak or strong adhesion depending on the field of application. However, design of “smart” surfaces with reversibly switchable/controllable adhesion is still a highly challenging task. Therefore, the thesis aims on design of smart polymeric materials with responsive / adaptive adhesion properties. For this, fabrication and investigation of two types of switchable polymer layers based on stimuli-responsive polymer brushes will be performed. The first group is dealing with thermoresponsive polymer brushes: poly-(N-isopropylacrylamide) and two types of biocompatible polyethylene glycol-based systems. These polymer layers undergo phase transition below and above LCST between hydrophilic and hydrophobic states. The second part of the work is related to solvent-responsive comb-like and block copolymer brushes consisted of hydrophilic PEG and hydrophobic PDMS biocompatible and biodegradable polymers.

[pt] Em veículos de competição com velocidades elevadas, o principal objetivo é chegar em primeiro lugar, o que significa percorrer um determinado número de voltas em uma trajetória fechada fazendo algumas manobras para cumprir o circuito no menor tempo possível, dentro das limitações impostas pelas caracteristicas dinâmicas e de condução destes veículos. A otimização é uma metodologia que pode ser usada para reproduzir trajetórias e técnicas de condução usadas pelos pilotos de corrida, e também para investigar os efeitos de vários parâmetros nas condições limites da estabilidade veicular. Neste trabalho, inicialmente é apresentado o desenvolvimento de um modelo dinâmico do veículo considerando as caracterítiscas suficientes para análise da trajetória, influenciada por parâmetros geométricos e físicos pertinentes. Em seguida é definido o problema de obtenção da trajetória empregando procedimentos de otimização, de modo a determinar como um veículo irá percorrer um traçado, considerando como função objetivo o tempo de percurso, que deverá ser mínimo, e tendo como restrições as condições dinâmicas do veículo e geométricas da pista, implementando rotinas que são usadas em conjunto com os algoritmos existentes na Optimization Toolbox do Matlab. Finalmente apresenta-se o comportamento do veículo, representado pelo modelo desenvolvido anteriormente em uma malha de controle de trajetória, de modo a comparar o comportamento assim obtido com aquele previsto pelo procedimento de otimização. / [en] High speed competition vehicles are required to cover a determined number of laps in a closed trajectory circuit in a time that is the least possible, in the limits of the governing dynamic and driving characteristics of these vehicles. Optimization is a methodology that can be used in order to simulate trajectories and driving techniques of used by the competition pilots and to investigate the effects of several parameters in limit conditions of car stability. In this work it is first presented the development of the vehicle model considering the sufficient characteristics for trajectory analysis, influenced by pertinent geometric and physical parameters. In continuation, the problem of the optimal trajectory is defined using optimization procedures, in order to determine how a vehicle will follow the path, considering as an objective function the time to follow it, that must be the minimum, and having as constraints the vehicle dynamic conditions and the path geometry, implementing routines that are used with the Matlab´s Optimization Toolbox. Finally the behavior of the vehicle is presented, represented by the model developed previously in a trajectory control loop, in such a way to compare the resulting behavior with the one predicted by the optimization procedure.