Thesis (Ph. D.)--Carleton University, 2004. / Includes bibliographical references (p. 281-299). Also available in electronic format on the Internet.

Thesis (M.S.)--University of Nevada, Reno, 2007. / "December, 2007." Includes bibliographical references (leaves 207-215). Online version available on the World Wide Web.

Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Atmospheric Science." Includes bibliographical references (p. 98-108).

Thesis (M.S.)--Villanova University, 2009. / Chemistry Dept. Includes bibliographical references.

Thesis (M.S.)--Brigham Young University. Dept. of Sociology. / Bibliography: leaves 91-95.

Thesis (M.Sc.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 69-79.

Thesis (M.A.)--Brigham Young University. Dept. of English, 2005. / Includes bibliographical references.

Ultra High Molecular Weight Polyethylene (UHMWPE) has been used as a ski sole material for many years due to its good tribological properties, good wear resistance and low friction coefficient. Recent studies have showed improved performance on wear rate and hydrophobicity with nanoparticle reinforced UHMWPE. In this study, different kinds of nano-composite UHMWPE’s were tested on snow to investigate if they are suitable as a ski sole material and to find the type of nano-composite UHMWPE that has the greatest potential. Further, the mechanisms of hydrophobicity and its influence on the friction level were examined. The friction coefficient was measured in a ski test rig and simple demonstrations under a microscope were made to simulate how water is dragged along the ski sole in contact with wet snow. Mechanical properties were measured with a CSM Nanoindentation Instrument and surface topography was examined in a Wyko Optical Profiler. The cross-linked UHMWPE material showed the lowest friction coefficient on snow. The hydrophobic demonstrations, together with the ski test results, questions the suggestion that high hydrophobicity enhances the ski glide. Nanoindentation was proved to give valuable data for mechanical properties, but it should be questioned whether it is a good technique for comparing different nano-composite UHMWPE materials. The ski tests show the importance of the characteristics of snow.

This study aimed to examine the possible conflicts between a rapidly growing snow mobile tourism and landowners of the region Funäsfjällen in the west of Sweden, close to the border of Norway. The newspapers of early 2018 was filled with landowner’s complaints about snowmobile users riding in areas where it was illegal and considered destructive by the landowners in big parts of northern Sweden. The landowners of the area of Funäsfjällen now threatened to tear up the agreement they had with the snowmobile trail. The method which was used in collecting opinions from landowners was through interview questions. Furthermore, the report is supposed to describe the current trends in snowmobile driving and sales, as well as describe the forest in the area. The study shows that land owners are overall positive to snow mobile tourism, but still showed that a majority of the landowners had been thinking about the trail agreement, and was prepared to tear it up if they did not see any improvements concerning destruction from free riding. Earlier studies showed that snow mobile sales from the latest years made new records, selling about 2 000 more units than average over the last ten years, where a majority of these were so called mountain snow mobiles, made for climbing steep hills and through deep snow. This study shows that the land owners experience an increase of general snow mobile tourism in the area. An earlier study published in the early 2000 showed that the problematic and destructive free riding had decreased quite a lot since the snow mobile trail in Funäsfjällen was opened. In this study though, it seems as something has changed over time, and the land owners now experience quite a big increase of illegal free riding in the area during the last five years, and that the economic compensation from the trail was not enough to cover the potential costs from the snow mobiles destruction on the land. The study also shows that the type of forest in the area was found to be a low productive one, where felling of trees needs a special permit from Skogsstyrelsen.

L'étude de la neige est un domaine important de la recherche en hydrologie et en météorologie. Il a été démontré que les propriétés physiques de la neige peuvent être récupérées en utilisant des capteurs à micro-ondes actifs. Cela nécessite une compréhension de l'interaction entre les ondes électromagnétiques (EM) et les milieux naturels. Dans ce but, le travail est divisé en deux étapes: étudier numériquement tous les modèles physiques de l'interaction onde-neige et développer un algorithme de diffusion inverse afin d’estimer la profondeur de la neige à partir de mesures de rétrodiffusion par un radar à des fréquences et angles d'incidence différents. L’objectif de la première partie consiste à effectuer les calculs de diffusion à l’aide d’un simulateur électromagnétique bien connu Ansoft High Frequency Structure Simulator (HFSS). Les simulations numériques prennent en considération: la permittivité effective de la neige, les phénomènes de diffusion surfacique dans des structures en couche des milieux homogènes (air-neige-sol) avec interfaces rugueuses ainsi que les phénomènes de diffusion volumique en traitant de la neige comme milieu dense. Par suite, le problème critique dans cette partie est de tester la validité des modèles théoriques à travers une configuration numérique adéquate.Dans la deuxième partie de ce travail, l'étude est étendue pour développer une méthode de récupération pour estimer l'épaisseur de la neige au-dessus du sol en utilisant la technique de mesures en rétrodiffusion en bande L et X (1,5 et 10 GHz) à des angles d'incidence différents. Le signal rétrodiffusé par la neige est influencé par: la diffusion surfacique, la diffusion volumique et les effets du bruit du système radar. Pour cela, le coefficient de rétrodiffusion du milieu est modélisé statistiquement en ajoutant un blanc bruit de fond gaussien (WGN) dans la simulation. Cet algorithme de diffusion inverse nécessite deux étapes de calcul. La première étape consiste à estimer la densité de la neige en utilisant le coefficient de rétrodiffusion co-polarisé en bande L à incidence normale. La deuxième étape consiste à estimer l'épaisseur de la neige à partir de coefficients de rétrodiffusion co-polarisés dans la bande X en utilisant deux différents angles d'incidence. Pour une variance de bruit de fond de 0,02, toutes les valeurs récupérées ont une erreur inférieure à 2% pour une gamme de profondeur de la neige de [50-300] cm. Cet algorithme a été vérifié par simulation à l'aide d’un logiciel de conception au niveau système, SystemVue. / Study of snow is an important domain of research in hydrology and meteorology. It has been demonstrated that snow physical properties can be retrieved using active microwave sensors. This requires an understanding of the interaction between electromagnetic (EM) waves with natural media. The objective of this work is two-fold: to study numerically all physical forward models concerning the EM wave interaction with snow and to develop an inverse scattering algorithm to estimate snow depth based on radar backscattering measurements at different frequencies and incidence angles. For the first part, the goal is to solve the scattering calculations by means of the well-known electromagnetic simulator Ansoft High Frequency Structure Simulator (HFSS). The numerical simulations include: the effective permittivity of snow, surface scattering phenomena in layered homogeneous media (air-snow-ground) with rough interfaces, and volume scattering phenomena when treating snow as a dense random media. So, the critical issue for the first part of this thesis is testing the validity of theoretical models through a careful numerical setup.For the second part, the study is extended to develop a retrieval method to estimate snow thickness over ground from backscattering observations at L- and X-band (1.5 and 10 GHz) using multiple incidence angles. The return signal from snow over ground is influenced by: surface scattering, volume scattering, and the noise effects of the radar system. So, the backscattering coefficient from the medium is modelled statistically by including a white Gaussian noise (WGN) into the simulation. This inversion algorithm involves two steps. The first is to estimate snow density using L-band co-polarized backscattering coefficient at normal incidence. The second is to estimate snow depth from X-band co-polarized backscattering coefficients using two different incidence angles. For a 0.02 noise variance, all retrieved values have an error less than 2% for a snow depth range of [50-300] cm. This algorithm was verified by simulating using Agilent’s SystemVue electronic system level design software.