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A cartonboard package is often sealed and closed with an adhesive – either a hot-melt adhesive (adhesives that are applied in a molten state on the cartonboard) or a dispersion adhesive (adhesives that are applied as water-based dispersions). This thesis focuses on the process of hot-melt gluing, and how material properties and process conditions affect the performance of the adhesive joint. Requirements vary depending on how the package is to be used. A package that is only supposed to protect the product during transport differs from one that is supposed to attract consumers and facilitate their use of the product. If a package has been opened, due to external or internal forces that cause a fracture in the adhesive joint, the consumer may choose another package instead. A fracture of the adhesive joint may occur in several different ways; for example, a cohesive fracture in the adhesive, an interfacial fracture between the adhesive and one of the cartonboard surfaces, and a cohesive fracture in the cartonboard. The traditional way of testing the adhesive joint is to subjectively evaluate the fibre tear after manually tearing the joint apart. The primary interest of this study has been to find an objective method that can characterise the adhesive joint – that is, its strength and joint characteristics. The work has principally concentrated on physical experiments where the Y-peel method has been evaluated and further developed, including the construction of a laboratory adhesive applicator. Adhesive joint failure is analysed and correlated to the force-elongation curve during Y-peel testing in order to explore various mechanisms of the failure. The force versus elongation curves are transformed into a force versus inelastic deformation curve for the adhesive joint. The inelastic deformation of the adhesive joint is defined as the inelastic opening of the adhesive joint perpendicular to the cartonboard surface. The dissipative descending energy has been used to characterise the adhesive joint. High descending dissipative energy showed high resistance against final failure of the joint. This correlates very well with the manual fibre-tear test. Characteristic force-elongation curves in Y-peel testing – that is, the shape of the curve – have been analysed, and four main failure modes have been identified. The finite element method has been used to predict mechanical behaviour in the ascending part of the force-elongation curve. When it comes to local behaviour, a high stiffness adhesive results in bending behaviour while a low results in shearing, but on a global scale, no big difference was detected on the ascending part of the force-elongation curve. The new laboratory adhesive applicator and finite element method can be used to objectively design the interaction between the adhesive and the cartonboard for a specific application. This can be achieved by modifying the cartonboard, the adhesive or the process parameters.

The circumpolar Arctic is experiencing dramatic environmental changes that are already impacting tundra ecosystems and northern communities that are intimately linked to the land. Increasing permafrost degradation, shrub encroachment, larger and more frequent fires, and increasing human development have significant effects on biotic and abiotic conditions in the lower Peel River watershed, NT. To understand and respond to rapid environmental changes, diverse knowledge perspectives are needed, so my M.Sc. research uses scientific and social scientific approaches to investigate environmental change in the lower Peel River watershed. I investigated the impacts of the Dempster highway on plants, soils and permafrost in the Peel Plateau by conducting field surveys at sites dominated either by tall alder (Alnus crispa) shrubs or by dwarf shrubs, at 30 m and 500 m from the highway. At each site I measured vegetation composition, alder growth, soil nutrients, litter and organic layer thickness, active layer thickness, and snow depth. We found that alder growth and recruitment were enhanced adjacent to the Dempster Highway, and dramatic alterations to plant community composition, soil properties and ground temperatures were observed where alder shrubs had formed closed canopies. Tall shrub sites adjacent to the road exhibited lower abundance of understory vegetation including mosses, greater litter and organic soil thickness, higher nutrient availability, and deeper snowpack. Biotic and abiotic changes associated with road effects feedback with alder canopy development, and have important implications for permafrost conditions adjacent to the roadbed, and potentially on road bed performance. This research contributes to our understanding of environmental changes caused by the highway and their consequences for infrastructure stability and pan-Arctic changes in vegetation cover. In a separate but complementary effort, I worked with Teetl’it Gwich’in land users and youth from Fort McPherson, NT to map observations of environmental conditions and changes. In the pilot year of a community-based environmental monitoring program, we employed participatory multimedia mapping with Teetl’it Gwich’in land users and youth from Fort McPherson, NT. I accompanied Gwich’in monitors on trips on the land to document environmental conditions and changes. Observations made by land users were documented using photos, videos and audio taken by youth, and land users provided detailed information about each observation in follow-up interviews. I compiled observations (photo/video, GPS location, and interview audio and transcript) into a web-based map where the public will be able to see changes on the land in the images and words of Gwich’in land users. The online map will provide a medium for local residents to communicate their knowledge and concerns about the environment, and will be useful for land management and planning, environmental monitoring, and adaptation. / Graduate / 0768 / 0329 / 0326 / hkgill@uvic.ca

High aspect ratio polymeric micro-patterns are ubiquitous in many fields ranging from sensors, actuators, optics, fluidics and medical. Second generation PDMS molds are replicated against first generation silicon molds created by deep reactive ion etching. In order to ensure successful demolding, the silicon molds are coated with a thin layer of C[subscript 4]F[subscript 8] plasma polymer to reduce the adhesion force. Peel force and demolding status are used to determine if delamination is successful. Response surface method is employed to provide insights on how changes in coil power, passivating time and gas flow conditions affect plasma polymerization of C[subscript 4]F[subscript 8]. / Singapore-MIT Alliance (SMA)

The peel test is a commonly used testing method for adhesive strength evaluation. The test involves peeling a pressure sensitive tape away from a substrate and measuring the peel force that is applied to rupture the adhesive bond. In the present study, the mechanics of the peel test is analyzed based on a cohesive zone model. Cohesive failure is assumed to prevail in the vicinity of the peel front, that is, the adhesive fails not by debonding from the adherends but by splitting of the adhesive itself. Generally, the failure of the adhesive is accompanied with a process of cavitation and fibrillation. Therefore, the cohesive zone is modeled as a continuous fibrillated region. A Maxwell model is employed to characterize the viscoelastic behavior of the adhesive. The governing equation and boundary conditions that describe the mechanics of the peel test are derived. Numerical results are obtained under steady state conditions. The model predicts the peel force in terms of the peel rate, the peel angle, the nature of the adhesive, and the properties of the backing and the substrate. The traction distribution on the substrate surface is found to depend on various test parameters. Finally, finite element analysis is performed using the commercial software package ABAQUS. The results from FEA are compared with those from the mathematical method to evaluate the validity of the present model. The effective range of the present model is found to be related to the ratio of the critical fibril length to the extent of the cohesive zone. Given the nature of the adhesive as well as the properties of the backing and the substrate, the proposed model is able to predict the peel force and the traction distribution in terms of the peel rate and the peel angle, and thus provides a measure of the strength of the adhesive bond.

The peel test is a commonly used testing method for adhesive strength evaluation. The test involves peeling a pressure sensitive tape away from a substrate and measuring the peel force that is applied to rupture the adhesive bond. In the present study, the mechanics of the peel test is analyzed based on a cohesive zone model. Cohesive failure is assumed to prevail in the vicinity of the peel front, that is, the adhesive fails not by debonding from the adherends but by splitting of the adhesive itself. Generally, the failure of the adhesive is accompanied with a process of cavitation and fibrillation. Therefore, the cohesive zone is modeled as a continuous fibrillated region. A Maxwell model is employed to characterize the viscoelastic behavior of the adhesive. The governing equation and boundary conditions that describe the mechanics of the peel test are derived. Numerical results are obtained under steady state conditions. The model predicts the peel force in terms of the peel rate, the peel angle, the nature of the adhesive, and the properties of the backing and the substrate. The traction distribution on the substrate surface is found to depend on various test parameters. Finally, finite element analysis is performed using the commercial software package ABAQUS. The results from FEA are compared with those from the mathematical method to evaluate the validity of the present model. The effective range of the present model is found to be related to the ratio of the critical fibril length to the extent of the cohesive zone. Given the nature of the adhesive as well as the properties of the backing and the substrate, the proposed model is able to predict the peel force and the traction distribution in terms of the peel rate and the peel angle, and thus provides a measure of the strength of the adhesive bond.

The Peel Watershed Planning Process began in the Yukon and Northwest Territories in 2004. This thesis describes the Peel Watershed Planning Commission and the main interests influencing the planning process. I explore the explanatory potential of several theories draw from urban political economy -- John Logan and Harvey Molotch’s growth machine thesis, Clarence Stone’s regime theory, and Bob Jessop and Neil Brenner’s account of rescaling the state – and suggest that each of these theories can be used to explain certain aspects of Peel Watershed politics. Then I turn to the assimilationist literature on First Nations in Canada – represented by the 1969 White Paper, Tom Flanagan’s First Nations?, Second Thoughts and Frances Widdowson and Albert Howard’s Disrobing the Aboriginal Industry – and contrast it with an alternative literature, represented especially by Paul Nadasdy’s Hunters and Bureaucrats. I argue that these literatures draw attention to aspects of the politics of planning that are neglected in the urban political economy literature, but are of obvious importance in the context of the Peel Watershed. Although questions of community preservation and wealth accumulation are central to the Peel Watershed planning process, worldviews and ways of life are also at stake. This suggests that we have to look at the politics of planning in very broad terms. / Graduate

Thesis--University of Missouri. / Vita. Includes bibliographical references (leaves [224]-234).

This work was performed as a preliminary transdermal drug delivery (TDD) study to investigate the diffusion characteristics and effects of skin surfactants in vitro of four active ingredients on a poly(dimethyl siloxane) polycarbonate copolymer membrane. A Franz-type diffusion cell and various receptor solutions were used. The adhesive used was comprised of a polyisobutylene-based pressure sensitive adhesive manufactured by Adhesives Research Inc. High performance liquid chromatography was used to analyze the diffusion characteristics of these systems. In addition, the effects of two skin surfactants (sodium lauryl sulfate and dimethyl sulfoxide) on the adhesive were also investigated. Results from peel testing and thermal analysis showed that the peel strength, glass transition, and softening temperature of the adhesive was greatly reduced with the addition of the surfactants. / Master of Engineering

The analysis of peeling tape or a bandage from skin is a challenging problem. Skin is a very complex material made of many layers with anisotropic material properties. Adhesives that bond tapes or patches to skin must attach to skin through moisture and skin movement, but then be removed with little skin trauma. A computer model of peeling from skin apparently has not been developed previously. With experiments and the application of mechanics, research was conducted to analyze adhesion to skin. Numerous peeling experiments were performed on human subject arms using 2.54-cm-wide pressure sensitive tape Durapore™ by 3M. Various rates, angles, and dwell times were tested. Testing machines recorded peel force and the displacement of the end of the tape. A range of maximum and average peeling force values were noted for human subjects, along with the influence of angle, rate, order of testing, dwell time, and subject. Also, rigid substrates were tested for comparison with human skin. Computer models were also developed to simulate peeling and skin behavior. Initial models dealt with peeling from a rigid surface, and intermediate models concerned plucking skin. The final model involved peeling a piece of tape from skin, the overall goal of this research. The skin and tape were modeled as they behave during peeling. With the final model, the peel angle, debonding moment, normal force on the skin, and net shear force tangential to the skin were analyzed. Results from the experiments and computer models of this research will increase knowledge of skin behavior and could contribute to improvements in the design of adhesives that contact the skin. / Master of Science