• Coping with bear country

      Greci, Dana (2001-12)
      'Coping with Bear Country' is a work of creative non-fiction, a genre in which non-fiction writers use dramatic techniques usually employed by fiction writers and poets (such as narration, dialogue, and detailed description) to look at their subjects. 'Coping with Bear Country' draws on the styles of nature writing, personal essay, and memoir, combining descriptions of natural history and tales of adventure with a look towards emotional landscapes reflected within them. At its most physical level, 'Coping with Bear Country' looks at the 'bearish' qualities of the complex land called Alaska, and at how a person simultaneously might both struggle against and embrace them. At this level, the work's focus is the author's personal struggle to make a home in a challenging land. But at its deepest level, 'Coping with Bear Country' digs more deeply, asking universal questions, exploring how faith takes root when we face our limitation and fear.
    • The cornerstone on Troth Yeddha': stories of Alaska Native college students

      Itoh, Taiyo; Topkok, Sean Asiqluq; Green, Carie; Hogan, Maureen; Hyslop, Polly (2020-05)
      Since the late 19th century, higher education has played three different roles in the Alaska Native rights movement: nurturing Native political leaders towards the Alaska Native Claims Settlement Act (1891-1971), teaching Alaska Native peoples how to manage their land and resources (1971-1990), and developing Native academic leadership from within universities (1991-2013). The previous studies revealed Alaskan universities' inadequate and discriminatory responsesto Alaska Native peoples' educational needs/wants after the 1960s, and further identified a wide range of factors affecting Alaska Native college students' academic achievement and wellbeing. The historical examination and the literature review collectively delineate Alaska Native peoples' experiences with universities in the past. In order to understand the status quo of Alaska Native higher education, three Alaska Native college students were interviewed about their college experiences and thoughts on higher education during the spring of 2019. All three students mentioned the benefit of having an Indigenous community on campus, and giving back as a reason to pursue postsecondary education. Each student also had a unique perspective that the other students did not share, which included the importance of Alaska Native language courses for cultural well-being, place identity crisis caused by the relocation from a home village to an urban campus, and the prejudice against the services Alaska Native college students receive. These findings can be used as a starting point for a discussion on how to improve higher education for future generations of Alaska Native peoples. As the very persons experiencing the long-standing effect of colonization, Alaska Native college students have a strong power to transform higher education. Hearing their stories is the key to achieving multicultural higher education and creating an equitable society in Alaska.
    • Correcting Oil-Water Relative Permeability Data For Capillary End Effect In Displacement Experiments

      Qadeer, Suhail (1988)
      By neglecting the effect of capillary forces, the relative permeabilities calculated by the method of Johnson, Bossler, and Neumann or Jones and Roszelle from low rate displacement experiments are in error.<p> In this study, steady state and displacement experiments were carried out. A history matching package along with a fully implicit numerical simulator and a Welge type model were developed and the displacement data were analyzed by history matching to quantify these errors. A modified centrifuge drainage bucket was used to obtain drainage and imbibition capillary pressure data.<p> The results show that in the case of drainage the non-wetting phase end point relative permeabilities and saturation exponents increase with an increase in rate. However the saturation exponent for the wetting phase decreases with rate. The wetting phase end point relative permeability stayed more or less constant with rate. In the case of imbibition these parameters did not indicate any meaningful rate dependent trend. <p>
    • Correlation Between Teacher Turnover Rates In The State Of Alaska And Standardized Test Scores In The Area Of Mathematics On The Standards Based Assessments/High School Qualifying Exam

      Roehl, Roy F., Ii; Brayboy, Bryan; Barnhardt, Raymond; Noble, Diane; Rickard, Anthony; Strange, Anthony (2010)
      This study utilized bivariate correlations, partial correlations, multivariate analysis including Hotelling-T, and observed power to investigate the possible correlations and connections of teacher turnover in Alaska's public school system to performance on the standards-based assessment of the Alaska High School Qualifying Exam (HSQE). The study focused on the results in the content area of mathematics involving the 10th grade standards-based assessment (SBA). Results from the study indicate two primary correlations exist as applied to the proficiency levels on the mathematics portion of the 10th grade mathematics SBA, teacher turnover and percent Alaska Native of school population. The results indicate that teacher turnover is statistically significant with an inverse relationship in relation to standards-based test scores, and the students most likely being impacted by teacher turnover are located in Alaska school districts that have large Alaska Native student populations.
    • Correlation of microstructure and thermo-mechanical properties of a novel hydrogen transport membrane

      Zhang, Yongjun; 张咏君; Bandopadhyay, Sukumar; Trainor, Tom; Balachandran, Uthamalingam; Nag, Nagendra (2014-05)
      A key part of the FutureGen concept is to support the production of hydrogen to fuel a 'hydrogen economy,' with the use of clean burning hydrogen in power-producing fuel cells, as well as for use as a transportation fuel. One of the key technical barriers to FutureGen deployment is reliable and efficient hydrogen separation technology. Most Hydrogen Transport Membrane (HTM) research currently focuses on separation technology and hydrogen flux characterization. No significant work has been performed on thermo-mechanical properties of HTMs. The objective of the thesis is to understand the structure-property correlation of HTM and to characterize (1) thermo mechanical properties under different reducing environments and thermal cycles (thermal shock), and (2) evaluate the stability of the novel HTM material. A novel HTM cermet bulk sample was characterized for its physical and mechanical properties at both room temperature and at elevated temperature up to 1000°C. Microstructural properties and residual stresses were evaluated in order to understand the changing mechanism of the microstructure and its effects on the mechanical properties of materials. A correlation of the microstructural and thermo mechanical properties of the HTM system was established for both HTM and the substrate material. Mechanical properties of both selected structural ceramics and the novel HTM cermet bulk sample are affected mainly by porosity and microstructural features, such as grain size and pore size-distribution. The Young's Modulus (E-value) is positively correlated to the flexural strength for materials with similar crystallographic structure. However, for different crystallographic materials, physical properties are independent of mechanical properties. Microstructural properties, particularly, grain size and crystallographic structure, and thermodynamic properties are the main factors affecting the mechanical properties at both room and high temperatures. The HTM cermet behaves more like an elastic material at room temperature and as a ductile material at temperature above 850°C. The oxidation and the plasticity of Pd phase mainly affected the mechanical properties of HTM cermet at high temperature, also as a result of thermal cycling. Residual stress induced in the HTM by thermo cycles also plays a very critical role in defining the thermo-mechanical properties.
    • Corrosion behavior and residual stress of microarc oxidation coated AZ31 magnesium alloy for biomedical applications

      Gu, Yanhong; Bandopadhyay, Sukumar; Severin, Kenneth P.; Chen, Cheng-fu; Kim, Sunwoo (2012-08)
      Mg alloys are potentially new biomaterials for bone repair or replacement. Appropriate coating is, however, needed to make the Mg alloy more resistant to corrosion. In this research, protective microarc oxidation (MAO) coatings were produced on AZ31 Mg alloys in sodium phosphate electrolyte. The coatings were produced under varying pulse frequency, applied voltage, oxidation time and electrolyte concentrations. This research analyzed the effects of the above four MAO process control parameters on the residual stresses and the corrosion behavior. Optimization of the MAO control parameters would allow production of AZ31 Mg alloy with high corrosion resistance. It is well accepted that residual stress and corrosion behavior are two significant factors in the development of AZ31 Mg alloys. The residual stresses in the MAO coatings were evaluated by the X-ray diffraction (XRD)-sin²ψ method. A predictive model of the residual stresses is proposed and a principal components analysis (PCA) was conducted to determine the contribution of the MAO control parameter on the residual stresses. Long-term corrosion behavior of MAO-coated Mg alloys was evaluated by the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The porosity of the samples after various immersion durations was evaluated by the potentiodynamic polarization method. The pre- and post- corrosion microstructures and the phase composition of MAO-coated samples were studied. Post-corrosion phase identification showed that hydroxyapatite (HA) was formed on the surface of the samples. The ratio of Ca/P in HA was determined by the X-Ray Fluorescence (XRF) technique. The degradation of the MAO-coated AZ31 alloys is reduced due to the MAO coating and the formation of a corrosion product layer. A predictive model of the corrosion current density is proposed and a PCA was conducted to determine the contributions of the individual MAO control parameter on the corrosion rate. The corrosion process and mechanism of MAO-coated AZ31 alloys in SBF were modeled based on the electrochemical corrosion results and the pre- and post-corrosion surface analysis. It is believed that under optimized control parameters, the MAO-coated AZ31 Mg alloy is superior implant material for biomedical applications.
    • Corrosion behavior of microarc oxidation and polycaprolactone coatings applied to AZ31 magnesium alloy evaluated in simulated body fluid and balanced salt solution

      Wilke, Benjamin M.; Zhang, Lei; Peterson, Rorik; Zhang, Junqing; Chen, Cheng-fu (2015-08)
      Recent research in orthopedic implant materials has focused on the use of magnesium alloys as a base material due to its mechanical properties similar to that of human bone. Rapid corrosion of magnesium materials in aqueous environments poses a significant hurdle to their application as a biomedical implant. A variety of coatings have been shown to improve the corrosion resistance of magnesium based materials in simulated body fluid environments including microarc oxidation and polymer coatings. However, formulation and corrosion rates vary significantly between solution types. Furthermore, in vivo results have shown that many common in vitro solutions over estimate corrosion rates. In addition to variations between solutions needing to be resolved, there has been little work performed to characterize large sample corrosion under stress. This is an essential step in evaluating concept performance at a macro scale, for application as a human implant. The experiments performed and presented in this thesis primarily involve the comparison of conventional simulated body fluid (c-SBF) and Earle's balanced salt solution (EBSS). Samples evaluated in these environments are microarc oxidation (MAO) coated AZ31 magnesium alloy and polycaprolactone dip-coated AZ31. MAO coated samples were created for a range of process settings to observe the effect of processing on corrosion performance. A dependence of MAO coating thickness on process voltage was found which augmented the initial corrosion resistance values observed via electrochemical testing. Both MAO and PCL coatings were found to improve the corrosion resistance of the samples as compared to uncoated AZ31. It was found that all variations (MAO, PCL, and uncoated) showed a reduced corrosion rate in EBSS as compared to c-SBF. This corrosion reduction was apparent through potentiodynamic scanning, electrochemical impedance spectroscopy, and visual inspection. Preliminary mechanical corrosion results, in the form of constant extension testing, showed no dependence of corrosion on stress level. Future work may be aimed towards expanding modes of mechanical testing and further refining simulated body fluids to fit with in vivo test results.
    • Corrosion behavior of titanium dioxide (TiO₂)-coated Al alloy in saline environment

      Rabbey, Md Fazlay; Zhang, Lei; Zhang, Junqing; Huang, Daisy; Peterson, Rorik (2018-08)
      Al alloys have been used in many applications, however, they are susceptible to corrosion when exposed in saline environment. In this work, TiO₂ nanoellipsoids with aspect ratios (AR) of 1, 2, 4 and 6 were synthesized, TiO₂ coatings of AR 1, AR2, AR4, and AR6 were fabricated on AA2024-T3 Al alloy substrate, and their corrosion behaviors in the saline environment were investigated by analyzing the scanning electron microscope (SEM) imaging, potentiodynamic polarization scans and electrochemical impedance spectroscopy. TiO₂-coated Al samples showed better corrosion performance compared to the bare Al sample. Among the coated samples, TiO₂ AR6 coated samples showed lower corrosion rate compared to other samples. Although TiO₂ nanoellipsoids coatings show good corrosion resistance, it is noted that TiO₂ coatings are porous, which allows the penetration of corrosive media through the pores to reach the surface of the substrate. A polystyrene (PS)-TiO₂ AR6 nanocomposite coating was fabricated, where the pores of the coatings were sealed by polystyrene, which is expected to further improve the corrosion resistance of TiO₂ coatings.
    • Coseismic deformation from the 2002 Denali Fault earthquake: contributions from synthetic aperture radar speckle tracking

      Elliott, Julie (2005-08)
      The technique of speckle tracking can provide coseismic surface offsets for an earthquake in regions where other geodetic data are not available. These offsets can be used to map the surface deformation and create slip distribution models. This thesis uses speckle tracking to study the 2002 Mw7.9 Denali Fault earthquake, with emphasis on the central section of the rupture. The Denali Fault earthquake began with a thrust event on the Susitna Glacier fault before rupturing unilaterally west to east on the Denali and Totschunda faults with overwhelmingly right-lateral strike-slip motion. A slip distribution estimated from a combination of speckle tracking data from the central section of the rupture, GPS data, and geologic data displays highly variable slip, with four major patches of high slip along the Denali fault. Compared to the primarily GPS-derived model of Hreinsdóttir [2005], the combined model is better constrained along the central rupture and predicts slip values much closer to the geologic offset measurements. A significant releasing bend in the fault just west of the pipeline can be correlated to a patch of high slip and the second-largest pulse of moment release along the rupture, suggesting that fault geometry plays an important role in earthquake mechanics.
    • Coseismic Deformation Of The 2001 El Salvador And 2002 Denali Fault Earthquakes From Gps Geodetic Measurements

      Hreinsdottir, Sigrun; Freymueller, Jeffrey T. (2005)
      GPS geodetic measurements are used to study two major earthquakes, the 2001 MW 7.7 El Salvador and 2002 MW 7.9 Denali Fault earthquakes. The 2001 MW 7.7 earthquake was a normal fault event in the subducting Cocos plate offshore El Salvador. Coseismic displacements of up to 15 mm were measured at permanent GPS stations in Central America. The GPS data were used to constrain the location of and slip on the normal fault. One month later a MW 6.6 strike-slip earthquake occurred in the overriding Caribbean plate. Coulomb stress changes estimated from the M W 7.7 earthquake suggest that it triggered the MW 6.6 earthquake. Coseismic displacement from the MW 6.6 earthquake, about 40 mm at a GPS station in El Salvador, indicates that the earthquake triggered additional slip on a fault close to the GPS station. The MW 6.6 earthquake further changed the stress field in the overriding Caribbean plate, with triggered seismic activity occurring west and possibly also to the east of the rupture in the days to months following the earthquake. The MW 7.9 Denali Fault earthquake ruptured three faults in the interior of Alaska. It initiated with a thrust motion on the Susitna Glacier fault but then ruptured the Denali and Totschunda faults with predominantly right-lateral strike-slip motion unilaterally from west to east. GPS data measured in the two weeks following the earthquake suggest a complex coseismic rupture along the faults with two main regions of moment release along the Denali fault. A large amount of additional data were collected in the year following the earthquake which greatly improved the resolution on the fault, revealing more details of the slip distribution. We estimate a total moment release of 6.81 x 1020 Nm in the earthquake with a M W 7.2 thrust subevent on Susitna Glacier fault. The slip on the Denali fault is highly variable, with 4 main pulses of moment release. The largest moment pulse corresponds to a MW 7.5 subevent, about 40 km west of the Denali-Totschunda fault junction. We estimate relatively low and shallow slip on the Totschunda fault.
    • Cosmic dust

      Manalang, Maria Belina S.; Mollett, David L.; Mason, Charles W.; Jones, Zoe Marie; Croskrey, Wendy E. (2015-12)
      My thesis is a body of work collectively entitled Cosmic Dust. It consists of different series of paintings that I've produced as a Master of Fine Arts student here at University of Alaska Fairbanks. These series are the Drip Paintings, Celestial Objects, and Ellipsoids. Elements from different series sometimes combine to form hybrid paintings. Although I have categorized my paintings into these three series, they have many elements in common. They are all related to natural phenomena involving continuous cycles and the effects of gravitational force.
    • Counterhistory in the literature of Juárez

      Burger, Hans (2011-05)
      Counterhistory in the Literature of Juárez deals with three novels portraying a series of unsolved murders in the city of Juárez, Mexico, including Stella Pope Duarte's If I Die in Juárez, Alicia Gaspar de Alba's Desert Blood: The Juarez Murders, and Roberto Bolano's 2666. The author argues that each novel creates an alternate historical record of the murders, as well as conditions in the city at large, which counters the understanding of the crimes which has been imposed by hegemonic forces in the Mexican and American governments. Because of their oppositional tactics, the author terms all three novels counterhistories, a word with complex and sometimes contradictory meanings in both literary criticism and metahistorical thought. The author explores various ideas of counterhistory and documents the ways each novel fulfills a counterhistorical purpose, as well as the ways in which the unique qualities of the novelistic form empower the creation of oppositional and polemical meanings.
    • Counting seals: estimating the unseen fraction using a covariate and capture-recapture model

      Moran, John R. (2003-08)
      We evaluated the influences of environmental covariates on the proportion of harbor seals (Phoca vitulina richardsi) ashore on Tugidak Island using a series of photographic capture-recapture experiments and ground based counts. We used general linear models to examine the significance of combinations of covariates including quadratics terms. Time of day, tide height, rate of tide change, surf, and wind speed significantly influenced the number of seals ashore during the molting period. The model including all significant covariates best explained the probability of seals being hauled out. We observed a decline in the local population using the haulout suggesting that seasonal migration affects the number of seals ashore. The relationship between covariates and the number of seals hauled out on Tugidak Island differ in some respects from those reported at other sites in Alaska, implying that a region wide application of a single correction factor to counts of hauled out harbor seals may not adequately account for seals at sea.
    • Coupling the effects of dissolved organic matter and nutrient Stoichiometry with nutrient uptake in boreal forest headwater streams

      Fjare, Dana; Jones, Jeremy; Harms, Tamara; Kielland, Knut (2015-08)
      Discontinuous permafrost affects the hydrology and distribution of vegetation in boreal forest watersheds, which in turn influence stream water chemistry. I investigated how loss of discontinuous permafrost with projected climate change might affect nutrient cycling in boreal forest headwater streams. I hypothesized that 1) the carbon, nitrogen, and phosphorus (C:N:P) ratio in dissolved organic matter (DOM) affects nutrient uptake due to stoichiometric constraints on autotrophic and heterotrophic nutrient assimilation, and 2) labile DOM affects nutrient uptake by increasing heterotrophic production. I tested my hypotheses using a series of instantaneous nutrient additions in nine headwater streams, with a factorial design manipulating both nutrient stoichiometry and DOM source. DOM was added as either acetate or leachate from birch leaves. Ambient nutrient uptake velocity (Vf-amb) was within the upper range of previously published literature values, ranging from 4.1-67.2 mm/min for N, 4.0-25.0 mm/min for P, and 4.2-34.5 mm/min for acetate. Uptake efficiency was similar for N and P added alone, in co-additions, and with DOM. Acetate and birch-DOM had similar effects on nutrient uptake, because both were sources of highly labile carbon. In 30-day laboratory bioavailability assays, birch and acetate-DOM exhibited ≥ 70% carbon loss. Vf-amb was in part explained by ambient stream chemistry, with Vf-amb for N weakly positively correlated with ambient P concentration, while Vf-amb for P and acetate was weakly negatively correlated with ambient N and ambient dissolved organic carbon, respectively. Consequently, inorganic nutrient availability may affect uptake of solutes as well as DOM lability. High demand for nutrients in boreal forest headwater streams suggests that uptake could increase concurrently with greater inorganic nutrient flux following a loss in permafrost extent.
    • Cowboy professionalism: a cultural study of big-mountain tourism in the last frontier

      Wagner, Forest J.; Cole, Terrence; Ehrlander, Mary; Heyne, Eric (2017-08)
      Geographical features and cultural traits may influence the character of big-mountain tourism in Alaska. For example, Alaska's wild landscape, rich climbing and skiing history, and cultural mythos of wilderness and frontier fostered its status as a major destination for niche big-mountain tourism. Growth in the industry since the 1980s has been phenomenal, though a change threatens the identity of mountain guides of the region, demanding they accept international standards for their self-regulating and uniquely Alaskan version of big-mountain tourism. This research project explored big-mountain niche tourism in Alaska, considering the influences of wilderness and frontier concepts on the tourism culture and examining guides' and clients' motivations for participation in the industry. I queried clients and guides at two guiding services, the Alaska Mountaineering School and its Denali mountain climbers, and Alaska Powder Descents and its Coast mountain heli-skiers. The quantitative client survey assessed participant motivations for engaging in big-mountain tourism, for hiring a guide, and for travelling to engage in mountain tourism. The qualitative guide interview asked guides their motivations for working in big-mountain tourism, their experience with the management of big-mountain risk, and changes they had observed over time in the industry. I am a professional mountain guide and instructor in Alaska and use this experience as a third data point. The findings showed that Alaska's big-mountain tourism offers individuals a transcendental, sublime, yet physical encounter, one that is part of a globalized political and economic system. Except for the guides themselves, the high mountains are generally accessible only to those who are at the high end of the socioeconomic spectrum. Gender is also a defining characteristic of the industry, as the guiding ranks and the clientele in Alaska's big-mountain tourism are overwhelmingly male. For guides, the frontier mythos of intrepid and rugged individualism is a powerful motivator, an identity construction that relates well with the depictions of the region in early literature, and in images promoted by the tourism industry. Clients on the other hand may come to Alaska because it is geographically exceptional, but they are not as enamored of the frontier ideology that resonates so deeply with many permanent residents.
    • Creating, communicating and measuring strategic objectives through the application of a balanced scorecard: the case of the University of Alaska Fairbanks Police Department

      McGee, Sean Eric; Duke, Rob; Berry, Kevin; May, Jeffrey (2015-08)
      This project served to align the vision and mission of the University of Alaska Fairbanks Police Department with the needs of the University community through the employment of a balanced scorecard. The balanced scorecard itself is a strategic performance management framework that enables organizations to identify, manage and measure strategic objectives. While there have been instances where police agencies have attempted to implement the balanced scorecard in the past, these police agencies have been very large, and they failed to achieve the level of granularity in their balanced scorecard necessary to effectively identify and manage true strategic objectives. In case of the University of Alaska Fairbanks Police Department, the balanced scorecard served to answer four fundamental questions: how will they sustain their ability to change and improve, what business processes must they excel at, how should they be perceived by their community, and how can they be responsible stewards of the funds that they are given?
    • Creep of grouted anchors in ice-rich silt

      Chen, Liangbiao (2011-05)
      Creep is a critical consideration for designing anchors in ice-rich silt. In this study, creep was evaluated for grouted anchors in ice-rich silt by laboratory tests. A total of nineteen staged-load pullout tests were conducted on smooth grouted anchors. The anchors were loaded until either a tertiary creep stage or the capacity of the load system was reached. Soil temperatures evaluated in this study ranged from 32 °F to 26.6 °F. It was found that the onset of tertiary creep for smooth anchors was around 0.03 inches, which was much smaller than that suggested in the literature for rough anchors (1.0 inch). Given the same shear stress and soil temperature, the observed creep displacement rates for smooth anchors were greater than those given by the existing design guidelines for rough anchors. A new creep model was proposed in which soil temperature was included as an additional variable. Model parameters were developed as a function of soil temperature and moisture contents by using the test data. The model predictions were compared with the laboratory tests. It was found that the creep displacement rates decreased with the decreasing of soil moisture contents and temperature. Based on the analysis of laboratory test data, design charts were provided to give the allowable pullout capacity for smooth anchors in ice-rich silt.
    • Critical Parameters In Magmatic Degassing

      Mongrain, Joanna; Larsen, Jessica (2008)
      Decompression experiments conducted at pressures up to 200MPa and temperatures of 825�C-880�C on hydrated K-phonolite and rhyolite melts were used to explore the critical parameters controlling nucleation, exsolution and degassing behavior. Experiments on the low viscosity/surface tension K-Phonolite melt highlighted the role of melt properties. Although the sample porosities deviated below equilibrium values for pressures less than ~40MPa, the melt exsolved water in equilibrium over all the pressures and decompression rates studied. Melt shearing is proposed to have caused bubble deformation and alignment, lowering the porosity at which extensive permeability develops and significant degassing occurs compared to rhyolite. Experiments on a rhyolite melt decompressed slowly from 100 MPa and then held at 10 MPa for up to 900 s highlighted the critical parameters controlling the formation and stability of a highly vesicular magma: bubble number density, bubble size distribution and porosity. The porosity of the interconnected, highly vesicular network decreased during "Stage I" degassing and the bubble size distribution evolved from a unimodal population to include a population of much larger bubbles. During Stage II degassing, the network collapsed. Pre-collapse and collapse degassing rates were obtained and a coalescence-induced coalescence model proposed to explain the rapid destabilization. The ability of a melt to efficiently exsolve volatiles and the ease of bubble coalescence are both a function of the initial distribution of nucleated bubbles. The development of a new method for quantifying this distribution using spatial statistics will allow future researchers to explore the underlying controls on nucleation such as melt structure and the occurrence of a prior nucleation event. To investigate the critical parameters controlling shallow dike intrusion and therefore magmatic ascent rate, the fracture mechanics of intrusion into homogeneous and layered (weak sandstone/strong granite) particle models under lithostatic, compressive and extensional regimes were examined. Although the scale of the model intrusions were an order of magnitude greater than field observations, extensive microfracturing across the weaker layers, parallel dike jointing in the stronger layers and a length scale dependence to fracture toughness were observed suggesting that the use of a particle code is a promising approach to intrusion modeling.