• Significant parameters of mining properties in arctic and subarctic areas of North America

      Hackney, D.A.; Lambert, C. (University of Alaska Mineral Industry Research Laboratory, 1983)
      This paper is a review of those factors unique to mining in the Arctic and subarctic. The information was developed from an exhaustive Literature search and personal visits to several northern mines in North America. The intent is to present a broad overview of many of these factors, to identify and stimulate consideration of parameters that are likely to be overlooked by companies end persons wlthout p rior arctic experience. Topics of discussion include exploration, cold weather plant design, blasting in permafrost, living conditions and employees relations. The appendices are a brief discussion of a number of the arctic and subarctic operations in North America. In brief, minlng in northern regions is practical provided the deposit has sufficient value to support the higher construction, transportation and operating costs associated with the remoteness and cold weather. Hiring and retaining good employees and integrating the native labor force into the operation have proven to be the most difficult problems. Equipment and plant operation are problems more easily solved.
    • SIMD within a register on linear feedback shift registers

      Ott, Karl (2015-04)
      Linear feedback shift registers (LFSRs) are used throughout a subset of cryptography. They have long been deployed as a means to generate a pseudo-random number stream. The random number generation provided by the LFSRs has been utilized in stream ciphers ranging from consumer to military grade. For example GSM privacy relies on the A5/1 stream cipher which in turn relies on LFSRs to generate the keystream. They are deployed because they are easy to construct, yet still provide strong cryptographic properties. The scope of this project is to speed up the simulation of LFSRs. The method of speeding up LFSRs is to use parallel operations to operate on multiple LFSRs at once. This is accomplished by using a method of SIMD. The method is SIMD within a register (SWAR). SWAR uses general purpose machine registers (eg. rax on an x86_64 machine). This means that 64 LFSRs can be simulated at once with one machine register using SWAR. This has the trade-off of latency vs throughput.
    • Simulation and analysis of wellbore stability in permafrost formation with FLAC

      Wang, Kai; Patil, Shirish; Chen, Gang (2015-07)
      Permafrost underlies approximately 80% of Alaska. Permafrost's high sensitivity to temperature variations plays a significant role in the stability of wellbores drilled through permafrost formations. Wellbore instability may cause stuck pipes, lost circulation, and/or collapse of the wellbore, resulting in extra cost and time loss. In order to minimize the influence of the heat produced during drilling, a vertical well is the only choice to penetrate permafrost formation. Fast Lagrangian Analysis of Continua (FLAC) was used in this simulation to test the minimum wellbore pressure to maintain stability in a permafrost formation. Three layers were set in the simulation model: clay, silt, and sand. With the drilling fluid temperature set at 343K and a 267K initial formation temperature, four different thermal times, i.e. 1 week, 1 month, 1 year, and 5 years, were tested to determine the minimum stable pressure. Pore pressure of the formation has the strongest effect on this pressure. And in a short operation period, drilling fluid temperature will not influence the minimum mud pressure value significantly. A regression analysis was conducted on the simulation results, and the minimum wellbore stable pressure was found to be a function of pore pressure, cohesion, frictional angle, temperature difference, conductivity difference, thermal time, and wellbore radius. With the help of this function, engineers could calculate stable pressure for wells in arctic area before drilling based on drilling fluid temperature.
    • Simulation based dimensionless waterflood performance curves for predicting recovery

      Dunn, Michael David (2000-08)
      Predicting waterflood recovery with simulation based dimensionless performance curves has advantages over the more traditional approaches in certain applications. This work discusses the advantages of the type curve approach in moderately mature fields where high resolution history matches are required. The method also has advantages when uncertainty analyses is important. The dimensionless type curve methodology can be applied to many different fields. A case study of a large, complex field is presented to show how the curves are created and how they can be applied. In this field, a study of the geology and stratigraphy indicated that reservoir continuity, permeability variance, and effects of faulting were the most important drivers of recovery efficiency. Simulations were performed on 45 datasets to describe waterflood performance over the range of variation. A spreadsheet program was created to predict recovery of any description, based on interpolations of the simulation results. The dimensionless curves can be used to predict full-field performance, as the basis of an integrated evaluation tool and/or for comparing actual performance to predicted performance. Using correlations to predict recoveries allows for ease of sensitivity analyses, and ease of application by casual users in an organization.
    • Simulation study on injection of CO₂-microemulsion for methane recovery from gas hydrate reservoirs

      Phale, Hemant A. (2006-08)
      Gas-hydrates are crystalline substances in which a solid water lattice accommodates gas molecules, such as methane, in a cage-like structure. A simulation study was conducted, both on 1-D and 2-D reservoir models, using STOMP-HYD simulator to evaluate a set of optimum parameters for methane recovery with simultaneous CO₂ sequestration. A simple 1-D analysis supports the hypothesis of enhanced gas-hydrate recovery using a CO₂-microemulsion injection technique. A series of simulations carried out on the 2-D reservoir model, revealed that the temperature and concentration of CO₂-microemulsion as well as initial CH₄-hydrate saturation in the reservoir are the key parameters in the replacement of CH₄ with CO₂ in the hydrate phase. The results from the 2-D analysis indicated that the moderate microemulsion with a CO₂ concentration in the range of 40% to 50% show good methane recoveries for the reservoir under consideration. Preliminary energy requirement calculations were also carried out to demonstrate the advantages of using the CO₂-microemulsion injection over the thermal stimulation method. These calculations indicated that the energy requirement for CO₂-microemulsion injection is less than 1/10th of that required in case of thermal stimulation method. The results support the hypothesis of using CO₂ microemulsion injection technique for methane recovery from gas-hydrate reservoirs.
    • Single lane live load distribution factor for decked precast / prestressed concrete girder bridges

      Millam, Jason Langdon (2004-08)
      The Alaska Department of Transportation (AKDOT) uses the decked precast, prestressed concrete bulb-tee girder for most of its bridge construction. The live load distribution factor (DF) equations provided by the American Association of State Highway and Transportation Officials (AASHTO) for the decked bulb-tee girder system do not differentiate between a single or multilane loaded condition. This practice results in a single lane load rating penalty for decked bulb-tee girder bridges. The research objective of this thesis is to determine DF simplified equations that accurately predict the distribution factor of the decked bulb-tee girder system when it is only subjected to single lane loading. Eight decked bulb-tee bridges were instrumented. Each bridge was loaded with a single load vehicle to simulate the single lane loaded condition. The experimental data were used to calibrate grillage models of the decked bulb-tee girder system. The calibrated grillage models were used to conduct a parametric study of the bulb-tee girder system subjected to single lane loaded condition. Eight new simplified equations that describe the single lane loaded distribution factor for both shear and moment forces of these bridges are developed in this thesis.
    • Site investigation, and GIS and slope stability analysis of a frozen debris lobe, south-central Brooks Range, Alaska

      Simpson, Jocelyn M.; Darrow, Margaret M.; Hubbard, Trent D.; Daanen, Ronald P.; Huang, Scott L. (2015-08)
      Frozen debris lobes (FDLs) are large masses of soil, rock, incorporated organic material, and ice moving down permafrost-affected slopes in the south-central Brooks Range, Alaska. Here we focus on FDL-A, which is an impending geohazard to the Dalton Highway, located just under 40 m away from the embankment. We present the results of multi-faceted research, including field-based studies, GIS analysis, laboratory testing of soil samples, and slope stability analysis. Subsurface instrumentation indicates that major movement of FDL-A occurs in a shear zone 20.6 to 22.8 m below the ground surface, with temperature-dependent internal flow as a secondary movement mechanism. Field observations indicate the presence of massive, infiltration ice associated with cracks on the surface of the lobe. Surface measurements show an overall average rate of movement of 1.2 cm per day, which is an increase over historic rates. The GIS analysis also provided insight into the movement and instability of FDL-A, and provided groundwork for a GIS protocol to examine catchment and lobe features of all FDLs along the highway corridor. The slope stability analysis required a back analysis to determine soil strength parameters at failure, resulting in cohesion values between 43 to 53 kPa and friction angles between 10° and 16°. The modeling results indicated a high sensitivity to cohesion and pore water pressure. This is critical since the melting of massive ice and thawing of frozen soil will increase pore water pressure and lower shear strength, resulting in the acceleration of FDL-A towards the Dalton Highway.
    • Sixth annual conference on alaskan placer mining

      Walsh, D.E.; Wray, Susan (University of Alaska Mineral Industry Research Laboratory, 1984)
      An abridged format of papers, presentations and addresses given during the 1984 conference held on March 28-29, 1984, compiled and edited by Daniel E. Walsh and M. Susan Wray.
    • Size Effects In Mesoscale Mechanical Testing Of Snow

      Huang, Daisy; Lee, Jonah; Newman, David; Peterson, Rorik; Truffer, Martin (2013)
      Snow is a naturally-occurring, heterogeneous material whose interactions with humans make it desirable for analysis as a geotechnical engineering material. In this study, clean, undisturbed, natural snows of two common types were collected in and around Fairbanks, Alaska and subjected to laboratory testing, and the results were compiled and analyzed. Three types of tests--flat pin indentation, unconfined compression, and cone penetration--were carried out while varying size parameters, and size effects were observed and studied. From flat-pin indentation testing, it was observed that first peak indentation strength initially fell exponentially with increasing indenter cross-sectional area, with the exponent averaging 0.84. Furthermore, the strength eventually rose to a plateau value, and the compression strength of snow could be calculated from this plateau value. This plateau, too, initially depended exponentially on the pin cross-sectional area for smaller pins. From unconfined compression testing, it was observed that as cross-sectional area of a flat pin indenter increased, plateau strength eventually reached that value found from unconfined compression testing. Furthermore, initial strength, plateau strength, and energy absorption density all increased linearly with increasing aspect ratio. From cone penetration testing, it was found that empirical values of snow strength may be obtained on both a micromechanical and macromechanical scale using cone penetration. Size effects, were also observed--smaller cone diameters and larger cone included angles yielded larger values for apparent snow strength. Some of the mechanisms behind all of these size effects are explainable from theory; others must be regarded for now as empirical in nature. In both cases, the results are quite reliable descriptors for a natural material, and may be safely interpolated from.

      Blank, Matt; Dockery, David; Pohl, Christina (2019-03)
      The purpose of this research was to evaluate how characteristics of hydraulic structures, such as slope or size, used at crossings over waterways relate to operation and maintenance (O&M) effort, fish passage, and stream function. Data on O&M concerns, fish passage concerns, and crossing characteristics were collected from 45 road-stream crossings in Prudhoe Bay, Alaska, during lower and higher water periods in both 2014 and 2015 (four events total). Logistic regression and generalized mixed models were used to examine relationships between O&M effort (response) and five explanatory variables. For all data from all years combined, there were no observable associations among O&M and culvert type or constriction ratio. However, lower constriction ratios were observed for sites with O&M needs in the June 2014 data set. The proportion of sites with both fish passage and O&M concerns was 0.52; comparatively, the proportion of sites with no fish passage concern but with O&M concern was 0.35.
    • Sludge Production and Disposal for Small Cold Climate Bio-Treatment Plants

      Tilsworth, Timothy (University of Alaska, Institute of Water Resources, 1972-12)
      Ultimate disposal of wastewater sludge has long been a problem which to a large degree has been ignored. Haney (1971) stated that: "Until process sludge can be handled with minimum environmental impact, we cannot claim to have a viable wastewater treatment process". The relationship of sludge disposal to total treatment processes is emphasized by the fact that sludge handling and disposal represents up to 50 percent of the total treatment capital and operating costs (Burd, 1968). Processing of wastewater sludge will, no doubt, receive increased attention in the future because of environmental concerns for our air, land and water. The present technology for processing wastewater treatment plant sludge is well established and includes conditioning, dewatering, and disposal. Many of these processes are highly sophisticated and relatively expensive. Most of the more advanced processes are unsuitable for small wastewater treatment facilities in Alaska.
    • Small scale implementation of a robotic urban search and rescue network

      Kibler, Steven G. (2012-05)
      With the advancement of robotics technologies, it is now possible to use robots for high risk jobs that have historically been accomplished by humans. One such example is the use of robots for Urban Search and Rescue (USR): finding chemical spills, fires, or human survivors in disaster areas. With the ability to include inexpensive wireless transceivers, it is possible to network numerous robots as part of a swarm that can explore an area much more expeditiously than a single robot can. With the inclusion of wireless capabilities comes the necessity to create a protocol for the communication between robots. Also necessary is the creation of an exploration protocol that allows the network of robots to explore such a building or search area in as little time as possible yet as accurately as possible. This thesis covers the development of such a network of robots, starting with the hardware/software co-design, the individual robots' control mechanisms, and their mapping and communications protocols.
    • Smart FRP Composite Sandwich Bridge Decks in Cold Regions

      Hulsey, J. Leroy; Qiao, Pizhong; Fan, Wei; McLean, David (Alaska University Transportation Center, 2011)
    • Snow Survey Results for the Central Alaskan Arctic, Arctic Circle to Arctic Ocean: Spring 2013

      Stuefer, Sveta; Homan, Joel; Gieck, Robert; Youcha, Emily (2014-02)
      Many remote areas of Alaska lack meteorological data; this is especially true for solid precipitation. Researchers at the University of Alaska Fairbanks, Water and Environmental Research Center have been collecting end-of-winter snow cover observations (depth, density, snow water equivalent and ablation) since the year 2000. These observations do not document the total snowfall during the winter, but provide quantitative estimate of cold season precipitation on the ground at winter’s end after sublimation and redistribution by wind. This report provides summary of snow cover data collected during cold season of 2012–2013. There are two main areas of study. One includes drainage areas of the western Sagavanirktok, Kuparuk, Itkillik, Anaktuvuk and Chandler Rivers located north of the continental divide in the Brooks Range. While the number of sites has varied each year, we visited 76 sites in April of 2013 on the North Slope of Alaska. Second study area was established in 2012 in the drainage areas of the Kogoluktuk, Mauneluk, Reed, Alatna, and Koyukuk Rivers south of the Brooks Range. Fifty seven new snow survey sites were visited south of the Brooks Range in April 2013. The cold season of 2012-2013 experienced heavy snowfalls (record amounts since 2000) north of the Brooks Range. This was the first year of data collection south of the Brooks Range, thus no comparison can be made. SWE averaged over entire study area was 13.1 cm in 2013, ranging from 1.2 cm to 35.2 cm. Generally, higher SWEs were found in the western portion of the study area. Ablation was later than normal in spring 2013. Ablation window extended from May 8, 2013 in the far south of the study area to middle June at higher elevations on the north side of the Brooks Range.
    • Snowmelt -frozen soil characteristics for a subarctic setting

      Kane, Douglas L.; Seifert, Richard D.; Fox, John D.; Taylor, George S. (University of Alaska, Institute of Water Resources, 1978-01)
      The pathways of soil water in cold climates are influenced, in addition to the normal forces, by the presence of permafrost and the temperature gradients in the soil system, whereas the infiltration of surface water into the soil system is a function of moisture levels, soil type and condition of the soil (whether it is frozen or not). Snowfall, with subsequent surface storage over a period of several months, typifies Alaskan winters. This snowfall often accounts for 50 per cent or more of the annual precipitation, with ablation occurring over a time span of 2 to 3 weeks in the spring. The melt period represents an event when large quantities of water may enter the soil system; the possibilities exist for recharging the groundwater system, or else generating surface runoff. The objective of this study was to determine the magnitude of potential groundwater recharge from snowmelt. Instrumentation was installed and monitored over two winter seasons to quantify the accumulation and ablation of the snowpack. Thermal and moisture data were collected to characterize the snow pack and soil conditions prior to, during, and following the ablation. Lysimeters were installed at various depths to intercept soil water. The volume of potential areal recharge for 1976 was 3.5 cm and for 1977 was 3.0 cm, which represented about 35 per cent of the maximum snowpack content. It is concluded that permafrost-free areas can contribute significantly to groundwater recharge during snowmelt ablation.
    • Snowmelt hydrology in the upper Kuparuk watershed, Alaska: observations and modeling

      Dean, Kelsey M.; Stuefer, Svetlana; Verbyla, David; Schnabel, William (2019-08)
      The Fourth National Climate Assessment Report (2018) indicates that Alaska has been warming at a rate two times greater than the global average with the Arctic continuing to be experiencing higher rates of warming. Snowmelt driven runoff is the largest hydrologic event of the year in many Alaska Arctic river systems. Changes to air temperature, permafrost, and snow cover impact the timing and magnitude of snowmelt runoff. This thesis examines the variability in hydrometeorological variables associated with snowmelt to better understand the timing and magnitude of snowmelt runoff in headwater streams of Arctic Alaska. The objectives of this thesis are to: (1) use observational data to evaluate trends in air temperature, precipitation, snow accumulation, and snowmelt runoff data; (2) relate precipitation, snow cover, and air temperature to snowmelt runoff using the physically-based Snowmelt Runoff Model (SRM) to test the applicability of the model for headwater streams in the Arctic. The focus of this study is the Upper Kuparuk watershed area, located in Alaska on the north side of the Brooks Range, where several monitoring programs have operated long enough to generate a 20-year climate record, 1993-2017. Long-term air temperature, precipitation, and streamflow data collected by the University of Alaska Fairbanks at the Water and Environmental Research Center and other agencies were used for statistical analysis and modeling. While no statistically significant trends in snow accumulation and snowmelt runoff were identified during 1993-2017, observations highlight large year-to-year variability and include extreme years. Snow water equivalent ranges from 5.4 to 17.6 cm (average 11.0 cm), peak snowmelt runoff ranges from 3.84 to 50.0 cms (average 22.4 cms), and snowmelt peak occurrence date ranges from May 13 to June 5 for the Upper Kuparuk period of record. The spring of 2015 stands out as the warmest, snowiest year on record in the Upper Kuparuk. To further investigate the runoff response to snowmelt in 2015, remote sensing snow data was analyzed and recommended parameters were developed for SRM use in the Upper Kuparuk watershed. Recommended parameters were then applied to 2013 snowmelt runoff as a test year. Model results varied between the two years and provide good first-order approximation of snowmelt runoff for headwater rivers in the Alaska Arctic.
    • A Software-Defined Radio Transmitter for Variable-Coded Modulation on a CubeSat

      Mullet, John; Thorsen, Denise L.; Raskovic, Dejan; Bossert, Katrina (2020-05)
      The large volume of satellites sharing the same spectrum and the complexities of communications in Low-Earth Orbit (LEO) pose challenges to the downlink of large volumes of data on a platform that is bandwidth, power, and time limited. LEO satellites operate in a highly variable communications environment due to variations in inter-satellite or satellite-to-ground geometries, weather, and interference. Therefore, there is motivation for implementing satellite communication techniques that manage these issues to increase the data throughput. One such technique is variable-coded modulation which shows improvement by taking advantage of the dynamic nature of a satellite link. As part of the Air Force Research Laboratory University Nanosatellite Program, and in collaboration with NASA, this project focuses on the development of an S-band software defined radio for CubeSats that utilizes variable-coded modulation defined by the Digital Video Broadcasting-Satellite-Second Generation standard. This project defense discusses the initial development and testing using GNU Radio, and the challenges for full implementation, as well as the current status of the transmitter, and future work.
    • Soil Stabilization Manual 2014 Update

      Hicks, R. Gary; Connor, Billy; McHattie, Robert (Alaska University Transportation Center, 2014-12)
      Soil Stabilization is used for a variety of activities including temporary wearing curses, working platforms, improving poor subgrade materials, upgrading marginal materials, dust control, and recycling old roads containing marginal materials. There are a number methods of stabilizing soils including modifying the gradation, the use of asphalt or cement stabilizers, geofiber stabilization and chemical stabilization. Selection of the method depends on the soil type, environment and application. This manual provide tools and guidance in the selection of the proper stabilization method and information on how to apply the method. A major portion of this manual is devoted to the use of stabilizing agents. The methods described here are considered best practices for Alaska.
    • Solar Assisted Culvert Thawing Device Phase I

      Zarling, John P. (1981-11)
      A solar assisted culvert thawing device has been designed, constructed, and installed as an alternate method for the prevention and control of roadway flooding and icing. The proposed solar thawing device is a maintenance-free system and relieves the labor-intensive and expensive culvert thawing methods presently used
    • Solar Assisted Culvert Thawing Device Phase II

      Zarling, John P.; Murray, Douglas H. (1983-05)
      A reflective type concentrating solar collector system has been designed, constructed and installed on an ice plugged roadway culvert as a means of melting a channel for water flow. The system consisted of four reflecting collectors, a circulating pump, and a thaw pipe mounted in the culvert. Photovoltaic panels were used as the source of power for the pump. A design analysis and performance characteristics are given for the solar collectors, circulating pump, and photovoltaic panels.