• Mapping and predicting the ionospheric effects to communication systems in northern aurora areas using the global positioning system

      Wang, Lingyun (2002-08)
      This thesis focuses on mapping and predicting ionospheric effects to communication systems in northern high latitude areas using GPS (Global Positioning System). The monitoring of ionospheric scintillation and TEC (Total Electron Content) over Fairbanks, Alaska has been achieved by using the GSV4004 GPS Ionospheric Scintillation and TEC Monitor (GISTM), which has been installed on the roof of Duckering Building at UAF since September 2001. The algorithm of acquiring equivalent vertical TEC above Fairbanks from various satellite measurements is given in detail. Both an empirical ionosphere model, IRI, and a physics-based ionosphere model, PIM, are used to verify the TEC real field measurement. Another signal estimation method, BP neural network, is used to forecast the TEC short-term variation, which can give better performance than the other two. The relationships among TEC, amplitude scintillation and phase scintillation are analyzed. Multipath effects and the impact to GPS performance from ionospheric scintillation are discussed. Lastly the TEC and scintillation index mapping around Fairbanks is presented.
    • Mapping impacts of education for wilderness management planning

      Foster, Frederick Anthony (1998)
      Wilderness education is considered a key response to abate physical impacts caused by wilderness recreationists, but education's impacts upon the psychological values of wilderness are unknown. This investigation used a wilderness purism scale to measure how minimum impact instruction affects the intensity and quality of a student's wilderness experience and the relation of these expectations and preferences to appreciation, knowledge, and concern for the environment as a whole, i.e., environmental literacy. A wilderness purism scale, a spatial scale, and wilderness management scale measured how wilderness education affects recreationists' limits of unacceptability in wilderness conditions. Effects of wilderness education on multiple perceptions of wilderness specific to particular groups, are explained. Methods of how these can be collected, organized, and mapped using a GIS approach are demonstrated and techniques to build a wilderness experience typology are outlined. The investigation determined that environmental literacy is correlated with wilderness purism. Student's expectations and ethical perspectives toward wilderness became stronger following wilderness leadership education courses, specifically, their perceptions of wildness, experiential factors, and ethical perspectives of the wilderness experience. Educational programs increased respondents' wilderness perceptions and their desired spatial buffer distances from unacceptable conditions in wilderness. Distances from sights and sounds were found to be critical to wildemess recreationists' wilderness experience relating to sensing unacceptable conditions inside wilderness boundaries and "knowing" that unacceptable (human-made) conditions do not exist. Educators may use the findings to better design and assess their program's effectiveness. Results of the methodology could aid Limits of Acceptable Change (LAC) process for wilderness planning. Wilderness managers may use the protocol to plan for the maintenance of wilderness opportunities to meet increasing demands brought about by education. Management must be prepared to protect suitable conditions for this potentially growing population. If managers zone wilderness accordingly to wilderness purism groups, they can protect vast areas from bio/physical impacts by using the processes described in this study. It is a tool for managing wilderness areas for a range of wilderness experiences which will aid in insuring protection of wildlife, ecosystem integrity, and native biodiversity.
    • Mapping landscape values and forest uses on the Tongass National Forest

      Schroeder, Britta; Verbyla, David; Brinkman, Todd; Fix, Peter (2014-05)
      Throughout the world, humans are often faced with the challenge of sustaining economic development while also promoting environmental stewardship. Such is true for the management history of the Tongass National Forest, where the U.S. Forest Service is transitioning away from harvesting old-growth and moving towards a more economically and environmentally sustainable approach. To measure the preferences of local community members affected by this transition, I conducted an interdisciplinary case study on the Wrangell Ranger District in Southeast Alaska. Community members from Wrangell mapped landscape values, acceptable and unacceptable forest uses. By assessing these landscape values and forest uses with respondents' attitudes towards forest management alternatives, I identify spatial locations of conflicting timber harvest uses and recommend forest management objectives for the district. Through public participation, communities can provide spatially explicit input during the planning process, which creates opportunities for managers to incorporate community needs and better prioritize management objectives.
    • Mapping methods and observations of surficial snow/ice cover at Redoubt and Pavlof volcanoes, Alaska using optical satellite imagery

      Rahilly, Kristen E.; Dehn, Jonathan; Pettit, Erin; Webley, Peter (2014-08)
      Alaska is a natural laboratory for the study of how active volcanism interacts with underlying seasonal snow, perennial snow, and glacial ice cover. While over half of the historically active volcanoes in Alaska have some degree of perennial snow or glacial ice, all Alaskan volcanoes have a covering of seasonal snow for a period of time throughout the year. Previous research has centered on how volcanic deposits erode away the underlying snow/ice cover during an eruption, producing volcanic mudflows called lahars. Less emphasis has been placed on how variations in the snow/ice cover substrate effect the efficiency of meltwater generation during a volcanic eruption. Glacial ice, perennial snow, and seasonal snow can all contribute significantly to meltwater, and therefore the variations in the types of snow/ice cover present at Alaskan volcanoes must be analyzed. By examining the changing spatial extent of seasonal snow present at a volcano during multiple Alaskan summers, the approximate boundaries of perennial snow and ice can be mapped as the snow/ice cover consistently present at the end of each ablation season. In this study, two methods of snow/ice cover mapping for Redoubt and Pavlof volcanoes are analyzed for efficiency and accuracy. Identification of the best method allows for mapping of the snow/ice cover consistently present during each Alaskan summer month over at least two different years. These maps can serve as approximations for the snow/ice cover likely to be present at both volcanoes during each summer month. Volcanic deposits produced during the 2009 Redoubt and 2013 Pavlof eruptions are spatially linked to these snow/ice cover maps so that future research can focus on the interaction between deposits and type of snow/ice substrate. Additional observations and conclusions are made regarding how the visible snow/ice cover varies during and after each eruption.
    • Margaret Keenan Harrais: A Biography In Four Voices

      Doetschman, Sarah; Carr, Richard (2011)
      Narrative strategies available to biography are explored through the life of Margaret Keenan Harrais---teacher, educational administrator, judge, and activist. Biography is a particular endeavor requiring flexible inquiry and creative presentation. Margaret is viewed through multiple lenses that explore personhood, encourage readers' introspection, and imply the importance of the individual in history. The four voices indicated in the title of this dissertation are editorial, analytical, sparsely Romantic, and expository. This biography aims to complicate readers' notions of what it means to be a person in relation to other people by focusing closely on selected episodes in Margaret's career; analyzing their historical, social, and literary import; and finally broadening the perspective to include the entirety of Margaret's life. The roles of the biographer and the reader are examined throughout in an attempt to explore the interconnections between biography and autobiography. Margaret's life is presented within the contexts of other women teachers in rural areas, as well as other men and women who wrote about territorial Alaska for a non-Alaskan audience. At heart this biography seeks to experiment with the narrative possibilities available to biographers, and to explore the ways in which the effects of these narratives allow for the contribution to general scholarship on the basis of particular experiences.
    • Marine associated bird and mammal habitat use at the Five Finger Lighthouse Island

      Beraha, Lori (2018-07)
      In summer 2017 I studied the abundance and distribution of marine associated birds and mammals from four observational points on the southernmost of the Five Finger Islands (FFI). My objectives were (1) to identify the areas of highest habitat use by species of conservation concern, and (2) to use this information to make recommendations for an ecosystem-based management plan at the Five Finger Lighthouse Island (FFLI). I found higher relative abundance and higher biodiversity of both birds and marine mammals on the South and West facing sectors compared to the North and East facing sectors. I attribute this to the greater habitat complexity that comprises a near-shore reef, a mixed kelp forest, and a channel between the reef and the side of the island with the highest cliff, areas used extensively for foraging, nesting, traveling, socializing, and resting by many of the documented species. I therefore recommend avoiding development and minimizing anthropogenic disturbance on the southern and western portions of the island including the adjacent reef and channel between the reef and island. As both the FFI ecosystem and the Five Finger Lighthouse (FFL) management continue to evolve in response to changing environmental conditions and human needs, this study provides a useful baseline for future comparison. Continued study and monitoring is also recommended at this site to inform future adaptive management, document changes over time, and engage community stakeholders in science and conservation.
    • Marine mammal and fishery interactions on the Copper River Delta and in Prince William Sound, Alaska

      Matkin, Craig O. (1980-12)
      An assessment of rate of damage to netted fishes and to fishing gear caused by marine mammals, and of rate of incidental catch and kill of marine mammals by fishermen, was undertaken for the salmon drift gillnet fisheries of the Copper River-Prince William Sound area, Alaska, in 1977 and 1978. Amounts of damage to netted fishes ranged from approximately 1.8 to 8.3 percent of the total catch. Damages were attributed to Steller sea lions (Eumetopias jubatus), which also were responsible for the majority of damages to nets, and to harbor seals (Phoca vitulina). Of the approximately 1000 mammals incidentally killed in 1978, about half were harbor seals and 40% were sea lions; the remainder were harbor and Dali porpoises (Phocoena phoccoena and Phocoenoides dalli) and sea otters (Enhydra tutris). Recommendations are made for modification of fishing methods to reduce the damages by and incidental kill of marine mammals.
    • Marine-derived nutrients in riverine ecosystems: developing tools for tracking movement and assessing effects in food webs on the Kenai Peninsula, Alaska

      Rinella, Daniel J. (2010-05)
      Marine-derived nutrients (MDN) delivered by spawning Pacific salmon (Oncorhynchus spp.) contribute to the productivity of riverine ecosystems. Optimizing methods for measuring MDN assimilation in food webs will foster the development of ecologically based resource management approaches. This dissertation aims to better understand relationships among spawning salmon abundance, biochemical measures of MDN assimilation, and the fitness of stream-dwelling fishes. The goals of my first research chapter were (1) to understand the factors that influence stable isotope ([delta]¹³C, [delta]¹⁵N, and [delta]³⁴S) and fatty acid measures of MDN assimilation in stream and riparian biota, and (2) to examine the ability of these measures to differentiate among sites that vary in spawning salmon biomass. For all biota studied, stable isotopes and fatty acids indicated that MDN assimilation increased with spawner abundance. Among Dolly Varden (Salvelinus malma), larger individuals assimilated proportionately more MDN. Seasonal effects were detected for aquatic macroinvertebrates and riparian horsetail (Equisetum fluviatile), but not for Dolly Varden. Of all dependent variables, Dolly Varden [delta]¹⁵N had the clearest relationship with spawner abundance, making this a good measure for monitoring MDN assimilation. Expanding on these results, two chapters examined potential fisheries management applications. The first sought to identify spawner levels above which stream-dwelling Dolly Varden and coho salmon (O. kisutch) parr cease to gain physiological benefits associated with MDN. RNA-DNA ratios (an index of recent growth rate) and energy density indicated saturation responses where values increased rapidly with spawner abundance up to approximately 1 kg/m² and then leveled off. In coho salmon parr, energy density and RNA-DNA ratios correlated significantly with [delta]¹⁵N. These results show strong linkages between MDN and fish fitness responses, while the saturation points may indicate spawner densities that balance salmon harvest with the ecological benefits of MDN. The second application tested a quick and inexpensive method for estimating, spawning salmon abundance based on [delta]¹⁵N in stream-dwelling fishes. Estimates made with coho salmon pair were unbiased, tightly correlated with observed values, and had a mean absolute deviation of 1.4 MT spawner biomass/km. Application of this method would allow estimates of annual escapement to be made on a potentially large number of streams.
    • Marine-entry timing and growth rates of juvenile chum salmon in Alaskan waters of the Chukchi and northern Bering Seas

      Vega, Stacy L.; Sutton, Trent; Adkison, Milo; Murphy, James (2015-08)
      Recent climate change is most pronounced in the Arctic, with many implications for juvenile salmon life-history patterns, such as altered timing of migrations and/or timing and success of life-history stages. The objectives of this study were to determine the timing of marine entry and early marine growth of juvenile Chum Salmon Oncorhynchus keta in the Chukchi and northern Bering seas. Sagittal otoliths were collected from juvenile Chum Salmon in summers 2007, 2012, and 2013 via surface trawls in the southern Chukchi and northern Bering seas. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to discriminate between freshwater and marine environments, and daily growth increments were counted to determine marine-entry dates and growth rates of juvenile Chum Salmon to make temporal and regional comparisons of juvenile characteristics. Marine-entry dates ranged from mid-June to mid-July, with all region and year combinations exhibiting similar characteristics with respect to entry timing, i.e., larger individuals at the time of capture entered the marine environment earlier in the growing season than smaller individuals. Juvenile growth rates were estimated to be, on average, 4.9 % body weight per day in both regions in summers 2007 and 2012, and 6.8% body weight per day in the Chukchi Sea in 2013. This study shows consistent conditions among regions with respect to juvenile Chum Salmon marine-entry timing, with some variation in growth rates. These results provide a novel and more thorough evaluation of juvenile Chum Salmon early life-history characteristics in the Alaskan Arctic and provide a baseline for comparisons with future climate change studies.
    • Market impacts and global implications of U.S. shale development and hydraulic fracturing: an economic, engineering, and environmental perspective

      Umweke, Maduabuchi Pascal; Baek, Jungho; Patil, Shirish; Perkins, Robert; Reynolds, Douglas (2018-05)
      The United States oil industry is experiencing a revolution because of significant oil production from tight oil plays since the mid-2000s. Advancements in horizontal well drilling and hydraulic fracturing are powering this new chapter in oil development. Increased oil production has brought billions of dollars of new revenue to oil companies involved in tight oil exploration and production, new jobs in the oil industry, and more tax revenue to oil regions around the U.S. However, tight oil resources do not only exist in the U.S. An understanding of the U.S. tight oil development experience could bring value to stakeholders within and outside the United States, and provide lessons and templates applicable in other tight oil regions. This research examines the U.S. tight oil experience and draws lessons for aspiring tight oil regions on the engineering, economic, and environmental fronts. On the economic front, I have examined an autoregressive distributed lag (ARDL) model on key oil industry macroeconomic data (West Texas Intermediate oil price, tight oil production, and rig count) from 2007 through 2016, and the impact of oil price on tight oil development for the Bakken, Eagle Ford, Niobrara, and Permian tight oil plays. The results show that oil companies in different plays react differently to oil price signals and do so in relation to oil field development characteristics. In addition, oil production and drilling intensity in the Eagle Ford play is found to be most responsive to oil price increases than the Permian, Bakken, or Niobrara oil plays. The Permian play was most resilient during the 2014 through 2016 oil price plunge. Oil production does not fall in response to a decrease in oil price, equally as it rises in response to oil price increase. Tight oil operators are quicker in bringing drilling rigs to service as prices rise than they take them away in response to falling oil prices, but do reduce drilling significantly in response to an oil price plunge. These results have significant ramifications for operators and assets in the respective oil plays or future plays with similar development characteristics. On the engineering front, I used petroleum engineering oil production forecasting Decline Curve Analysis techniques, the Drillinginfo Software, and historical development data of U.S. plays, to conduct oil production forecast for seven U.S. tight oil plays. Forecast results are shown to be comparable to forecasts by the Energy Information Administration (EIA). Building on previous EIA geologic studies on non-U.S. tight oil plays, and by selecting best analogues from within U.S. tight oil plays, I have completed an economic assessment and uncertainty analysis for 10 non-U.S. tight plays using a simple fiscal tax regime. The results indicate that the Eagle Ford play in Mexico, the Vaca Muerta play in Argentina, and the Qingshankou play in China rank highest among the plays studied. Of oil price, royalty rate, discount rate, well cost, extraction tax, and recovery factor parameters evaluated, results indicate that oil price and well cost are among the biggest drivers of profitability in these plays. On the environmental front, I conducted case studies on the busiest U.S. tight oil plays (Bakken and Eagle Ford) and examined the impact of tight oil development on the environment. Local solutions to environmental challenges alongside environmental regulations are discussed and presented as possible templates for other aspiring plays. Since securing freshwater sources alongside wastewater management emerge as major issues in tight oil development, a cost comparison is conducted for reused water disposal versus one-use water disposal options, for a hypothetical development. Results indicate that on a cost-per-well basis, the reduction in water disposal volume from subsurface frack flowback retention improves water reuse economics; the water reuse option is preferable to one-use water disposal for U.S. oil plays. This result points to potential cost savings for reused water disposal in regions such as the Bakken with few disposal wells.
    • Market opportunities for carbon sequestration in Alaska

      Duval, Jennifer Elizabeth (2004-12)
      Global climate change has been at the forefront of environmental concerns for the last few decades. Based on the success of the United States' sulfur dioxide cap-and-trade program, a market for greenhouse gas emissions has slowly emerged. Russia's recent ratification of the Kyoto Protocol will bring an international market into force in February 2005. This thesis examines the economic theory behind cap-and-trade markets as solutions for environmental problems and discusses the characteristics of the markets for greenhouse gas emissions. The opportunities for Alaska's participation are examined, particularly offsetting diesel emissions from rural generators with wood or alternative energies. The calculations estimate that the rural diesel offset program could potentially earn 274,000 Verified Emissions Reductions annually, which the State of Alaska could sell to buyers to enhance its resource development revenue stream.
    • A market survey of ecotourists in the Valdivian temperate forest ecoregion of Chile

      Harris, Scott (2004-12)
      A survey of ecotourists in the Valdivian Temperate Forests ecoregion of southern Chile is used to determine if the experience and activity preferences of the market match what is being developed at local community-based ecotourism projects. It also compares the motivations of the same market with the motivations outlined in the definition of ecotourism. Survey design was based on a literature review, and observations and key-informant interviews collected in the study area. Ecotourists show strong preferences for the types of accommodations and experiences that exist or are being developed at ecotourism project sites: hostels, camping, low-intensity nature-based activities, pristine environments, and simple marketing schemes. However, market demand for guide services may not meet expectations. Survey respondents who support ecotourism goals fall into a tightly defined cluster, the majority of whom are Chilean. Proponents of ecotourism development in this area have expectations that generally conform to the guidelines presented in the case study literature, and ecotourism can complement the improving, but currently weak, political capacity for conserving native forest biodiversity in this region.
    • Martingales in mark-recapture experiments with constant recruitment and survival

      Humphrey, Patricia Buslee (1995)
      The method known as mark-recapture has been used for almost one hundred years in assessing animal populations. For many years, these models were restricted to closed populations; no changes to the population were assumed to occur through either migration or births and deaths. Numerous estimators for the closed population have been proposed through the years, some of the most recent by Paul Yip which make use of martingales to derive the necessary estimates. The independently derived Jolly-Seber model (1965) was the first to address the open population situation. That method as originally proposed is cumbersome mathematically due to the large number of parameters to be estimated as well as the inability to obtain estimates until the end of a series of capture events since some of the "observed" variables necessary are prospective. It also is cumbersome for the biologist in the field as individual marks and capture histories are required for each animal. Variations have been proposed through the years which hold survival and/or capture probabilities constant across capture occasions. Models based on log-linear estimators have also been proposed (Cormack 1989). This paper builds on the closed population work of Yip in using martingale-based conditional least squares to estimate population parameters for an open population where it is assumed recruitment of new individuals into the population is constant from one capture occasion to the next, and capture and survival probabilities are constant across capture occasions. It is an improvement over most other methods in that no detailed capture histories are needed; animals are simply noted as marked or unmarked. Performance of the estimator proposed is studied through computer simulation and comparison with classical estimators on actual data sets.
    • Masked rituals of the Kodiak Archipelago

      Desson, Dominique; Black, Lydia T.; Pierce, Richard A.; Schweitzer, Peter P.; Morrow, Phyllis; Leer, Jeff (1995)
      The traditional culture of the Alutiiq speakers of the Kodiak Archipelago is not well known, and information on their spiritual and ritual life has been lacking. In this thesis I use ethnographic, ethnohistoric, and iconographic materials to investigate the Koniag traditional world view and belief system and some aspects of the Koniag ritual system. Specifically, I analyze the individual, private masked rituals associated with whaling and the public masked rituals performed during the winter festivals. In the second part, I examine a large sample of surviving Alutiiq masks in order to determine aesthetic canons evident in the work of 19th and 20th century Koniag carvers. Visual preferences in mask making in terms of construction, volumes, shapes, colors, and designs are defined and differences in those preferences between the three Alutiiq speakers' groups of the Kodiak Archipelago, Prince William Sound, and the Alaska Peninsula are discussed.
    • Mass Balances And Dynamic Changes Of The Bering, Malaspina, And Icy Bay Glacier Systems Of Alaska, United States, And Yukon, Canada

      Muskett, Reginald R.; Lingle, Craig (2007)
      The Bering and the Malaspina Glacier systems of south-central Alaska, U.S.A., and southwest Yukon Territory, Canada, in the Saint Elias Mountains constitute the two largest temperate surge-type piedmont glaciers on Earth. This is largest region of glaciers and icefields in continental North America. Determining and understanding the causes of wastage of these two glaciers is important to understanding the linkages of glacier mass balance to climate change, glacier dynamics, and the contributions of the glaciers of northwestern North America to rising sea level. Presented are the first detailed estimate of the net mass balances of the Bering and Malaspina Glacier systems, the effects of glacier dynamics on their accumulation areas, and the wastage of the tidewater glaciers of Icy Bay. The combined wastage of the Bering and Malaspina Glacier systems from 1972 to 2003, 254 +/- 16 km 3 water equivalent over a glacier area of 7734 km2, is equivalent to an area-average mass balance of -1.06 +/- 0.07 m/y over that time period. This represents a contribution to global sea-level rise of 0.70 +/- 0.05 mm, 0.023 +/- 0.002 mm/yr from 1972 to 2003. This is roughly 0.8% of the modern sea-level rise as estimated from tide-gauges and satellites, and roughly 9% of the contribution from non-polar glaciers and ice caps. Glacier wastage has been caused by climate warming (negative mass balance) superimposed on the effects of glacier dynamics. Near-concurrent surge of the three largest glaciers of the Malaspina Glacier piedmont were observed during 1999 to 2002. In addition, the tidewater Tyndall Glacier, whose retreat since 1910 was interrupted in 1964 by a major surge, also surged during 1999 to 2002. These four surges have occurred roughly 23 years after the 1976/77 shift of the Pacific Decadal Oscillation to its current warm-wet phase. Despite the increase of high-elevation snow accumulation observed on Mt. Logan, the accumulation areas of the Bering and Malaspina Glacier systems are being drawn down by the effects of glacier dynamics. Wastage has accelerated since 2000.
    • Mass media theory and women's zines on the world wide web

      Wagaman, Jennifer Elaine (2000-08)
      Two mass media theories, 'Spiral of Silence theory' and 'Uses and Gratifications theory, ' have been used to explain and evaluate media usage from a feminist perspective. These theories both succeed and fail when used to analyze the World Wide Web as a mass medium. In order to effectively examine so-called 'fringe' groups and their publications on the Web, a new theory is needed that considers the more user-driven interface that the Internet and the World Wide Web provide for users. Using a modest case study of women's Web zines, (online underground magazines) this paper attempts to show how some young women use the World Wide Web to publish a different proportion of ideas and opinions than those currently available in the mainstream mass media, and goes on to show that the two current mass media theories used most by feminists are inadequate for the study of the World Wide Web as a mass medium. This paper takes into consideration historical theoretical approaches to the mass media, as well as the social constructionist principles important to looking at the media from a feminist point of view. Finally, it lays a framework of theoretical assumptions that should be considered when examining the Web as a mass medium.
    • Mass transfer study on CO₂ penetration through methane hydrates using CO₂ vapor and a CO₂ nucleated micro-emulsion

      White, Aaron N. (2003-12)
      Gas hydrates are solid inclusion compounds that are made up of ice and large amounts of guest gas molecules. Due to their abundance in nature and the ability to entrap large amounts of natural gas, progress towards tapping this energy resource is on the forefront of research. Much research on the kinetics of formation and decomposition needs to be completed. This study was comprised of the identification of CH₄ and CO₂ through their characteristic Peak Raman shifts, the determination of the mass transfer rates of CO₂ through pre-formed methane hydrate, and an experimental injectant using a dissociated CO₂ micro-emulsion to help destabilize the CH₄ hydrate zone. Identification experiments showed that characteristic peak locations were instrument dependent and that O-H stretch analysis could help in the determination of the phase gas was in. Mass transfer rates were obtained for CO₂ penetration through methane hydrates by a headspace swap in an associated free gas zone. Experimental temperatures of the hydrate zone were 0, 2.5, and 4.5°C. Results indicate that CO₂ can penetrate into CH₄ hydrate zone by dissociating the CH4 from a hydrate phase and stabilizing the mixed CO₂-CH₄ hydrates. The process is slow in the magnitude of 10⁻⁸ meters per second.
    • Massive ice interactions with offshore structures

      Lu, Mingchi (1992)
      The interaction between a multiyear sea ice floe of variable thickness, and an offshore structure, has been examined using a 3-dimensional finite element method. Elastic response within the ice floe was assumed initially, and a uniform loading of the ice floe by the adjacent pack ice was used. As an example of the results for a frozen boundary condition at the ice/structure contact zone, with a central region of the ice floe having its thickness reduced to 50% as compared to the floe thickness at the structure ($\Delta$t/t = 0.5), tensile cracks first form at the top surface in the thinnest area of the floe. The total force on the structure was 108 MN, as compared with 1500 MN which would be present in the case of an ice floe of uniform thickness. Parameters varied were ice/structure contact zone (located in the centric or the eccentric region), the sliding boundary condition, two-dimensional ice thickness variation, variable ice elastic modulus as a function of depth, and viscoelastic ice behavior. Cases of rigid and of compliant structure and foundation were included. In a second part of the study, the ice island loads acting upon a cylindrical rigid structure were analyzed by this 3-dimensional finite element method. A force of 6600 MN was computed to be acting on the structure with a maximum penetration distance of 8.2 m. A different theoretical method based upon multiyear ice field data resulted in a force of 336 MN and a maximum penetration distance of 75 m. The ice forces on the structure are reduced by ice floe thickness variations, and also are affected by the geometries at the ice floe/structure and ice floe/pack ice boundaries. The reduced elastic modulus in the warmer. lower part of an ice sheet promotes ice bending failure and causes lower structure loads.
    • Master's research project : transient migrations and responses to effective change for Mixtec indigenous youth

      Hennessey, Maura A.; Barnhardt, Ray; Gerlach, Craig; Ruppert, James (2014-04)
      This qualitative research was developed not knowing the outcome. The primary goal was to find an indigenous group that resided in the Monterey Bay region of the Central Coast of California. Thanks to the Pajaro Valley Unified School District's Migrant Education Office, this goal was accomplished by the introduction of the Mixtec culture of Oaxaca, in Southern Mexico. The research began by 'hanging out' with the Mixtecs at Adult Education English class building a trust and familiarity. Their primary language is Mixteco,. Lessons were in Spanish to learn English. The project all fell into place after being introduced to Lucia, a trilingual 25 yr. old Mixteca. The secondary goal was in understanding their environmental relationship to identity. Since the Mixtecs are immigrants it was necessary to 1) get acquainted with their history, and homeland 2) attempt to understand purpose and risks to 'sneak across the border' 3) adjustment to life in California. Eight interviews were performed. Seven interviews were in their native language, Mixteco. Lucia's interview was in English and Spanish. A hand held device recorded the interviews. All interview questions were formulated in a partnership with Lucia. The translations are composed genuinely from her indigenous perspective. To acquire first hand photos, three cameras were used by the informants as they worked 'on the job' in the agricultural fields. The interviewees from their personal files donated pictures of their Oaxacan villages. Common themes were identified and are summarized in this report. The data was collected and compiled. The research brought forth a narrative nonfiction, young adult book, requested by the Mixtec students, as the rest of this project lays it out.