• Attenuation and Effectiveness of Triclopyr and 2, 4-D Along Alaska Highway Rights-of-Way in a Continental and a Coastal Subarctic Environment

      Barnes, David; Seefeldt, Steve (Alaska University Transportation Center, 2009-12)
      After more than 20 years of only mechanical brush cutting, ADOT&PF evaluated the use of herbicides to manage vegetation that interferes with line-of-sight and maintenance of the roadway. While researchers have investigated herbicide effectiveness and attenuation in more-temperate climates, little study has focused on cold regions. The purpose of this project was to measure the effectiveness and attenuation of two different selective auxin-type herbicides, 2, 4 dichlorophenoxyacetic acid (2,4-D), and 3,5,6-trichloro-2-pyridinyl acetic acid (triclopyr) in two subarctic climates; an extremely cold continental climate and a maritime climate. Conclusions from this study will aid the ADOT&PF in developing a plan for controlling vegetation along highway rights-of-way in Alaska.
    • Attenuation and Effectiveness of Triclopyr and 2,4-D Along Alaska Highway Rights-of-Way in a Continental and a Coastal Subarctic Environment

      Barnes, David L.; Seefeldt, Steve (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2009)
    • Attitude determination for small satellites using gps signal-to-noise ratio

      Peters, Daniel; Raskovic, Dejan; Hawkins, Joseph; Thorsen, Denise (2014-05)
      An embedded system for GPS-based attitude determination (AD) using signal-to-noise (SNR) measurements was developed for CubeSat applications. The design serves as an evaluation testbed for conducting ground based experiments using various computational methods and antenna types to determine the optimum AD accuracy. Raw GPS data is also stored to non-volatile memory for downloading and post analysis. Two low-power microcontrollers are used for processing and to display information on a graphic screen for real-time performance evaluations. A new parallel inter-processor communication protocol was developed that is faster and uses less power than existing standard protocols. A shorted annular patch (SAP) antenna was fabricated for the initial ground-based AD experiments with the testbed. Static AD estimations with RMS errors in the range of 2.5° to 4.8° were achieved over a range of off-zenith attitudes.
    • AUTC Newsletter v1 n1

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2007-04)
    • AUTC Newsletter v2 n1

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2008-06)
    • AUTC Newsletter v2 n2

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2009-03)
    • AUTC Newsletter v3 n1

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2009-05)
    • AUTC Newsletter v3 n2

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2010-02)
    • AUTC newsletter v4 n1

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2010-05)
    • AUTC Newsletter v4 n2

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2010-12)
    • AUTC Newsletter v5 n1

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2011-05)
    • AUTC Newsletter v5 n2

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2012-04)
    • AUTC Newsletter v6 n1

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2012-06)
    • AUTC Newsletter v6 n2

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2013-01)
    • AUTC Newsletter v7 n1

      Alaska University Transportation Center (Alaska University Transportation Center, University of Alaska Fairbanks, 2013-07)
    • Automated processing system for tidal analysis of MF radar winds

      Vemula, Sreenivas (2005-12)
      The medium frequency (MF) radar at Platteville, Colorado (40.18° N, 104.7° W) is used to estimate the zonal and meridional wind motions in the middle atmosphere. This radar has been in operation since January 2000. We currently have four years of wind estimates sampled every five minutes. An automated processing system has been developed in IDL to process these estimates and obtain the monthly mean winds and tidal parameters. The automated processing currently processes the wind estimates in time domain analysis using a least square fitting technique. The criteria for determining when the estimated tidal parameters are valid have been studied along with the error analysis of the data and processing. The diurnal and semidiurnal parameters are obtained using this least square fitting method and these tidal parameters are assumed to be valid only when the condition number is less than 10. In the spectral domain, the fast Fourier transform and Lomb-Scargle periodogram methods have been studied. A test signal is generated and its performance using both FFT and Lomb-Scargle methods are discussed for three different cases which are equivalent to our actual data. The results of the wind estimates from 2000-2003 collected using the MF radar have been processed using the automated processing system. This automated processing system can be used to generate the wind parameters on a 24 hour, 7 day a week basis for an elaborate study. Our data are compared with MF radar data from Saskatoon, Canada and Urbana, lllinois. Most of the time our data are similar to the behavior of GSWM-02 model.
    • Automatic detection of sensor calibration errors in mining industry

      Pothina, Rambabu; Ganguli, Rajive; Ghosh, Tathagata; Lawlor, Orion; Barry, Ronald (2017-12)
      Sensor errors cost the mining industry millions of dollars in losses each year. Unlike gross errors, "calibration errors" are subtle, develop over time, and are difficult to identify. Economic losses start accumulating even when errors are small. Therefore, the aim of this research was to develop methods to identify calibration errors well before they become obvious. The goal in this research was to detect errors at a bias as low as 2% in magnitude. The innovative strategy developed relied on relationships between a variety of sensors to detect when a given sensor started to stray. Sensors in a carbon stripping circuit at a gold processing facility (Pogo Mine) in Alaska were chosen for the study. The results from the initial application of classical statistical methods like correlation, aggregation and principal component analysis (PCA), and the signal processing methods (FFT), to find bias (±10%) in "feed" sensor data from a semi-autogenous (SAG) grinding mill operation (Fort Knox mine, Alaska) were not promising due to the non-linear and non-stationary nature of the process characteristics. Therefore, those techniques were replaced with some innovative data mining techniques when the focus shifted to Pogo Mine, where the task was to detect calibration errors in strip vessel temperature sensors in the carbon stripping circuit. The new techniques used data from two strip vessel temperature sensors (S1 and S2), four heat exchanger related temperature sensors (H1 through H4), barren flow sensor (BARNFL) and a glycol flow sensor (GLYFL). These eight sensors were deemed to be part of the same process. To detect when the calibration of one of the strip vessel temperature sensors, S1, started to stray, tests were designed to detect changes in relationship between the eight temperature sensors. Data was filtered ("threshold") based on process characteristics prior to being used in tests. The tests combined basic concepts such as moving windows of time, ratios (ratio of one sensor data to data from a set of sensors), tracking of maximum values, etc. Error was triggered when certain rules were violated. A 2% error was randomly introduced into one of the two strip vessel temperature data streams to simulate calibration errors. Some tests were less effective than others at detecting the simulated errors. The tests that used GLYFL and BARNFL were not very effective. On the other hand, the tests that used total "Heat" of all the heat exchanger sensors were very effective. When the tests were administered together ("Combined test"), they have a high success rate (95%) in terms of True alarms, i.e., tests detecting bias after it is introduced. In those True alarms, for 75% of the cases, the introduction of the error was detected within 39.5 days. A -2% random error was detected with a similar success rate.
    • Axisymmetric numerical heat transfer analysis of natural gas hydrates reservoir

      Subbaihaannadurai, Vijayagandeeban; Das, Debendra K.; Patil, Shirish L.; Goering, Douglas J. (2004-12)
      Gas hydrates are crystalline substances, occurring in nature under high pressure and low temperature. Numerical studies were conducted on dissociation of gas hydrate to recover natural gas. The model is a cylindrical geometry with a wellbore at the center through which hot water is injected. Through this thermal stimulation technique frozen hydrate reservoir is melted and natural gas is released. The computational fluid dynamics software FLUENT was adopted to generate the model. The initial model was solely comprised of a hydrate layer. This model was refined by adding the overburden and the underburden to the hydrate and exploring the thermal regime of the entire composite medium. Unsteady state results showing the dissociation front propagation with respect to time were calculated. In the first part, the hydrate medium is dissociated by the conduction phenomenon only. In the second part, due to the porous nature of the hydrate medium, both conduction and convection phenomena are considered. This thesis presents the following results obtained from simulations using Fluent. They are: temperature rise within the reservoir with time, temperature profiles in the radial direction, and steady and transient state solutions of the dissociation of gas hydrate with the liquid fraction in the reservoir. Comparison of our results with a finite difference model and a finite element model is also included. Volumes of gas released with respect to time and thermal efficiency ratios are also determined.
    • Baseline geochemical studies for resource evaluation of D-2 Lands - geophysical and geochemical investigations at the Red Dog and Drenchwater Creek mineral occurrences

      Metz, P.A., Robinson, M.S., and Lueck, L. (University of Alaska Mineral Industry Research Laboratory, 1979)
      Major zinc, lead and barite mineralization has been discovered at Red Dog and Drenchwater Creeks in the DeLong Mountains of north-western Alaska. The host rocks for the mineral occurrences are carbonates, cherts, shales, and dacitic volcanic rocks of the Mississippian Lisburne Group. The host rocks are deformed in a narrow belt of imbricate thrust sheets that extend from the Canadian border to the Chukchi Sea. The rocks strike generally east-west and dip to the south. The sulfide minerals occur as stratiform mineralization parallel to bedding planes, as breccia fillings and vein replacements, and as disseminations in the various host rocks. The primary ore minerals are sphalerite, pyrite, pyrrhotite, and galena. Barite occurs as massive beds up to 90 meters (300 feet) thick at Red Dog Creek and as nodules, veinlets, and disseminations at Drenchwater Creek. Close spaced soil sampling, mercury vapor sampling, and magnetic and radiometric surveys were conducted over the areas of exposed sulfide mineralization to test the response of these techniques to these types of deposits in northern Alaska. There is potential for additional deposits of this type in the Lisburne Group of the entire northern Brooks Range. These techniques provide a rapid low cost method for the discovery and preliminary evaluation of these types of mineral occurrences in northern Alaska.
    • Behavior Of Granular Materials Under Cyclic And Repeated Loading

      Minassian, George H.; Raad, Lutfi (2003)
      Granular layers are essential contributors to the structural integrity of the pavement system, their premature deformation radically decrease support of the asphalt concrete surface layer, thus leading to the early deterioration of the overall pavement structure. This research was conducted to better understand the behavior of granular materials when subjected to the complex nature of traffic loading. Long-term triaxial tests were conducted on typical Alaskan base course material using both repeated as well as cyclic loading to also account for the shear reversal effects induced by wheel load. Results show that the shear reversal component of the traffic loads, which have been ignored so far, induces considerable damage to the granular layers. Models were presented to predict the different soil moduli while also accounting the effect of strain hardening or densification due to the repetitive nature of the loads applied. Moreover, a simple yet powerful model was presented to predict accumulated permanent strains as function of the stress state, number of load repetitions and the strength level applied. The results obtained in this study also show a clear indication of the existence of given stress level limit beyond which incremental collapse of the system takes place. Furthermore, regions of instability of granular layers subjected to dynamic loading have been defined using a simple response parameter and monotonic shear strength of the soil. An effort was made to explain the instability zones identified in this research by the shakedown theory.* *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Microsoft Office.