• Calibration of an on-line analyzer using neural network modeling

      Yu, Shaohai (2003-08)
      The goal of the project was to predict the ash content of raw coal in real time using the Americium-137 and Cesium-241 scintillation counts from an on-line analyzer. Rather than regression methods (that are current industrial practice), neural networks were used to map the scintillation counts to percentage ash. Quick stop training was used to prevent overfitting The noise and sparseness of the data required that the training, calibration and prediction subsets are statistically similar to each other. Therefore, Kohonen networks were first used to detect the features present in the data set. Three subsets were then built such that they had representative members from each feature. Neural network models were developed for the screened coal, the unscreened coal and the combined data respectively. The results show that the performance of the combined model was comparable to the performance with two different models for the screened and unscreened data. Due to the variance in the sample data, the neural networks (screened, unscreened and combined) did not predict individual samples well. The network predictions were, however, accurate on the average. Compared to the common regression approach, neural network modeling demonstrated much better performance in ash prediction based on certain criteria.
    • Calibration of microbolometer infrared cameras for measuring volcanic ash mass loading

      Carroll, Russell C.; Hawkins, Joseph; Thorsen, Denise; Raskovic, Dejan; Hatfield, Michael (2014-08)
      Small spacecraft with thermal infrared (TIR) imaging capabilities are needed to detect dangerous levels of volcanic ash that can severely damage jet aircraft engines and must be avoided. Grounding aircraft after a volcanic eruption may cost the airlines millions of dollars per day, while accurate knowledge of volcanic ash density might allow for safely routing aircraft around dangerous levels of volcanic ash. There are currently limited numbers of satellites with TIR imaging capabilities so the elapsed time between revisits can be large, and these instruments can only resolve total mass loading along the line-of-sight. Multiple small satellites could allow for decreased revisit times as well as multiple viewing angles to reveal the three-dimensional structure of the ash cloud through stereoscopic techniques. This paper presents the design and laboratory evaluation of a TIR imaging system that is designed to fit within the resource constraints of a multi-unit CubeSat to detect volcanic ash mass loading. The laboratory prototype of this TIR imaging system uses a commercial off-theshelf (COTS) camera with an uncooled microbolometer sensor, two narrowband filters, a black body source and a custom filter wheel. The infrared imaging system detects the difference in attenuation of volcanic ash at 11 μm and 12 μm by measuring the brightness temperature at each band. The brightness temperature difference method is used to measure the column mass loading. Multi-aspect images and stereoscopic techniques are needed to estimate the mass density from the mass loading, which is the measured mass per unit area. Laboratory measurements are used to characterize the noise level and thermal stability of the sensor. A calibration technique is developed to compensate for sensor temperature drift. The detection threshold of volcanic ash density of this TIR imaging system is found to be from 0.35 mg/m3 to 26 mg/m3 for ash clouds that have thickness of 1 km, while ash cloud densities greater than 2.0 mg/m3 are considered dangerous to aircraft. This analysis demonstrates that a TIR imaging system for determining whether the volcanic ash density is dangerous for aircraft is feasible for multi-unit Cubesat platforms.
    • Carbon Monoxide Exposure and Human Health

      Joy, Richard W.; Tilsworth, Timothy; Williams, Darrell D. (University of Alaska, Institute of Water Resources, 1975-02)
    • A case/control analysis and comparison of indoor air quality in Alaskan homes

      Dinakaran, Satish; Johnson, Ron; Naidu, Sathy; Lin, Chuen-Sen; Seifert, Rich (2005-08)
      Indoor Air Quality (IAQ) parameters such as CO, CO₂, relative humidity, temperature, radon, particulate matter, formaldehyde, benzene, toluene, hexane, Total Volatile Organic Compounds (TVOC) and microbial matter were monitored before and after remediation in 36 low-income homes in Alaska (Hooper Bay and Fairbanks). The objective was to see if there was any improvement in IAQ with remediation. Hooper Bay homes had significantly higher levels of CO₂ and relative humidity compared to Fairbanks homes both before and after remediation. There was a general reduction in CO₂ with remediation, although it was not statistically significant. When IAQ in two moderate-income homes in Fairbanks was compared with that in the remediated low-income homes, it was observed that indoor CO₂ levels were affected by ventilation rates and per capita floor area. A single zone model to predict concentration of indoor pollutants was constructed, using steady state and transient mass conservation, to predict, metabolically produced CO₂, and particulate matter when no indoor sources were present. The cost of energy to reduce indoor CO₂ levels in one of the homes by increasing ventilation by either using an exhaust-only system or a Heat Recovery Ventilator (HRV) is discussed.
    • A Catalog of Hydroclimatological Data for Alaska's Coastal Zone

      Carlson, Robert F.; Weller, Gunter (University of Alaska, Institute of Water Resources, 1972-05)
      In order to perceive a better understanding of the interrelationships of the coastal zone water we proposed a research project which was to sort out many of the complex variables. The project was not begun due to the lack of sufficient funds. We did, however, begin a limited literature search and listing of hydroclimatological data sources of Alaska's coastal zone. We felt this would be a modest but useful start towards the larger study. It should also have some practical usefulness to others. This data catalog is a result of this initial study. Because of the wide variety of types of agency which collect data and the literally hundreds of sources through which they are reported, it is often quite bewildering for even experienced investigators to sort out what can be found and where. Although we are sure that the catalog is far from complete, we feel that it is a useful beginning towards an attempt to better understand the hydroclimatological processes in Alaska's coastal zone. We wish to invite contributions and criticisms which could lead to an improved and more comprehensive version at some future date.
    • The Characteristics and Ultimate Disposal of Waste Septic Tank Sludge

      Tilsworth, Timothy (University of Alaska, Institute of Water Resources, 1974-11)
    • Characteristics and utilization of fly ash

      Lu, F.C.; Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1971)
      Fly ash produced by four power plants in Fairbanks and vicinity was collected and analyzed. Current fly ash specification and potential users of fly ash in general and in the Fairbanks area in particular were evaluated. A detailed bibliography on utilization of fly ash is appended for reference by producers and potential users of fly ash.
    • Characterization and evaluation of washability of Alaskan coals

      Rao, P.D.; Wolff, E.N. (University of Alaska Mineral Industry Research Laboratory, 1980)
      This report is a result of the second part of a continuing study to obtain washability data for Alaskan coals to supplement the efforts of the U.S. Department of Energy in their ongoing studies on washability of U.S. coals.
    • Characterization and evaluation of washability of Alaskan coals - fifty selected seams from various coal fields

      Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1986)
      FINAL TECHNICAL REPORT: September 30,1976 to February 28,1986
    • Characterization and evaluation of washability of Alaskan coals - phase i - selected seams from Nenana, Jarvis Creek and Matanuska coal fields

      Rao, P.D.; Wolff, E.N. (University of Alaska Mineral Industry Research Laboratory, 1979)
      This report covers the results of a study conducted to obtain washability data for Alaskan coals to supplement the efforts of the U.S. Department of Energy (formerly U.S. Bureau of Mines) in its ongoing studies on washability of U.S. coals.
    • Characterization and evaluation of washability of Alaskan coals - phase iii, selected seams from the northern Alaska, Nulato, Eagle, Nenana, Broad Pass, Kenai, Beluga, and Chignik coal fields

      Rao, P.D.; Wolff, E.N. (University of Alaska Mineral Industry Research Laboratory, 1982)
      This report is a result of the third part of a continuing study to obtain washability date for Alaskan coals, to supplement the efforts of the U.S. Department of Energy in their ongoing studies on washability of U.S. coals. Washability characteristics were determined for fifteen coal samples from the Northern Alaska, Nulato, Eagle, Nenana, Broad Pass, Kenai, Beluga and Chignik coal fields. The raw coals were crushed to 1-1/2 inches, 2/8 inch and 14 mesh topsizes, and float-sink separations were made at 1.30, 1.40 and 1.70 specific gravities.
    • Characterization and evaluation of washability of Alaskan Coals - phase iv, selected seams from the northern Alaska, Chicago Creek, Unalakleet, Nenana, Matanuska, Beluga, Yentna, and Herendeen Bay coal fields

      Rao, P.D.; Wolff, E.N. (University of Alaska Mineral Industry Research Laboratory, 1982)
      This report is a result of the fourth and final part of a study to obtain washability data for Alaskan coals, to supplement the efforts of the U.S. Department of Energy in their ongoing studies on washability of U.S. coals. Washability characteristics were determined for fifteen coal samples from the Northern Alaska, Chicago Creek, Unalakleet, Nenana, Matanuska, Beluga, Yentna and Herendeen Bay coal fields. The raw coal was crushed to 1 1/2 inches, 3/8 inch and 14 mesh top sizes, and float-sink separations were made at 1.30, 1.40 and 1.60 specific gravities.
    • Characterization and fluid flow properties of frozen rock systems of Umiat Oil Field, Alaska

      Godabrelidze, Vasil (2010-12)
      The Umiat field, located in northwestern Alaska between the Brooks Range and the Arctic Ocean, potentially contains the largest accumulation of oil in Naval Petroleum Reserve No.4. Most of the oil is found within the permafrost zone. The main oil-producing zones in the Umiat field are marine sandstones in the Grandstand Formation of the Cretaceous Nanushuk group. Although the temperatures are close to freezing, the oil in the Umiat field remains unfrozen due to its very high API gravity. However, this results in a very unique pore space containing frozen water and oil, posing a particular challenge to characterization and measurement of fluid flow properties necessary for production. The unsteady-state gas-oil relative permeability measurement experiments were conducted in order to obtain critical information about the properties of two-phase fluid flow through the Umiat porous medium. Fluid flow experiments at 22°C and -10°C on representative core samples from the Umiat field showed 61% average decline in oil relative permeability as a result of freezing irreducible water. Capillary pressure measurement experiments were also carried out on selected core samples with an intention of characterizing their pore size distribution. Subsequently obtained data indicates fairly wide range of pore size for Umiat cores.
    • Characterization and implementation of stress dependent resilient modulus of asphalt treated base for flexible pavement design

      Li, Peng; 鹏 李; Liu, Juanyu; Connor, William; Zhang, Xiang; Shur, Yuri; Saboundjian, Stephan (2013-08)
      Asphalt treated base (ATB) is the most commonly used type of stabilized material in pavements because of material availability and relatively low cost in Alaska. The treatment enhances the material's properties to overcome deficiencies in some marginal materials. Resilient modulus (MR) of these materials is an essential pavement design input. Currently, in the Alaska Flexible Pavement Design (AKFPD) Manual, MRS of ATBs were back calculated using testing results of falling weight deflectometer (FWD). There is a need for an accurate laboratory characterization of these materials. In this study, the MRS of hot asphalt treated base (HATB), emulsifed asphalt treated base (EATB), foamed asphalt treated base (FATB), and a mixture of reclaimed asphalt pavement (RAP) and D-1 aggregate at a 50: 50 ratio (RAP 50:50) were measured using repeated triaxial tests. D-1 granular materials used for base course construction were collected from three regions in Alaska. HATB specimens were compacted using Superpave gyratory compactor and three binder contents were used: 2.5%, 3.5% and 4.5%. EATB and FATB specimens were compacted according to ASTM D1557 and three residual binder contents were used: 1.5%, 2.5% and 3.5%. RAP 50:50 was also compacted according to ASTM D1557 and no additional additives were added. MR was measured at three temperatures (i.e. -10°C, 0°C, 20°C for HATB, EATB and FATB; -10°C, -2°C, 20°C for RAP 50:50). The stress-dependent property of MR was successfully characterized by the modified universal soil model, in which the MR was expressed as a function of bulk stress (θ) and octahedral shear stress (τoct). Generally, MR increased with an increase of θ and decreased with an increase of τoct. Stress-dependent patterns of each type of ATB were analyzed and discussed. Predictive equations for MR were developed for all types of ATBs investigated in this study. The equations were based on the modified universal soil model. The material properties (i.e. binder content and percentage fracture surface), temperature and the interactions among them were incorporated into equations. The developed predictive equations had very high coefficient of determination (R²). The R² s of equations HATB_10, EATB_10, FATB_10 and RAP_9, in which the influencing factors and second order interactions among factors were included, were all greater than 99%. These equations can be also used to estimate nonlinear elastic constants of ATBs in the modified universal soil model (i.e. k₁, k₂ and k₃). The stress dependent property of MR was incorporated into pavement structural analysis using the finite element method (FEM) program Abaqus through user defined material that was programmed in the user subroutine. Comparisons were made between pavement responses obtained from nonlinear FEM and traditional linear elastic layered system. The representative MR of ATBs were determined and recommended based on the equivalent critical pavement response of the typical Alaska flexible pavement structure. Predictive equations were developed to estimate the critical pavement responses. The equations were developed through regression analyses using a database generated from 16,848 nonlinear pavement FEM analyses, which covered a variety of pavement structure combinations. These nonlinear pavement analyses were implemented through the function of a parametric study provided in Abaqus FEM package. In total 9 independent variables were included, which were the thickness of the surface course, base course, and subbase, moduli of HMA, subbase and subgrade, and nonlinear elastic constants of ATB (i.e. k₁ k₂ k₃) in the MR model. The interactions among these variables were also included. The R²s of predictive equations were at least 0.9725. The predictive equations can be used for routine pavement analysis and design purposes.
    • Characterization and washability studies of raw coal from the Little Tonzona Field, Alaska

      Rao, P.D.; Walsh, D.E.; Phillips, N.; Charlie, K.G. (University of Alaska Mineral Industry Research Laboratory, 1991)
      Coal occurs in an isolated exposure of Tertiary, non-marine sedimentary rocks along the southwest bank of the Little Tonzona River, near Farewell, Alaska. The Little Tonzona River coal field is located approximately 150 air miles northwest of Anchorage, Alaska, and 210 air miles southwest of Fairbanks, Alaska; near the boundaries of Denali National Park. The Alaska Railroad and the Parks Highway are approximately 100 air miles from the coal field at their nearest point. The village of McGrath, on the Kuskokwim River, is located approximately 90 miles to the west (1). An impressive outcrop of coal-bearing Tertiary sediments is exposed for a distance of more than 275 feet on the west bank of the Little Tonzona River (Figure 1). More than seven coal beds, ranging in thickness from 3 feet ta 30 feet, with a cumulative thickness of over 134 feet, are interbedded with clay beds up to 40 feet thick. The clays are fine textured, extremely plastic, light grey to nearly white bentonites andlor tonsteins. Doyon Ltd., an ANSCA Native Corporation, holds land selections covering the inferred limits of the coal field. During 1980 and 1981, Doyon entered into exploration agreements with McIntyre Mines Inc. of Nevada. The two season exploration program took place from June 1,1980 through August 22,1980 and from May 27,1981 through August 22, 1981. During the 1980 field season, geologic mapping, prospecting, stratigraphy, trenching and bulk sampling of all coal outcrops were performed. This produced a total of 34 samples, which were taken for analysis. In 1981, six diamond drill holes with a cumulative length of 2,935 feet were completed. Core recovery was close to 90%, and a total of 147 coal samples, which represented 802.8 cumulative feet of coal, were taken for analysis. The exploration program confirmed a strike length of over 3 miles to the southwest from the main river bank exposure. Northward extension is unknown at this time. Although outcrop exposure is poor away from the river banks, burnout zones resulting from past coal bed fires form a resistant, recognizable on strike feature in the relatively unindurated Tertialy sequence. The appearance of these burnout zones along strike is often the only surface indication of the buried coal-bearing strata. Well preserved plant fossil impressions in the baked clays date the deposit as probable Miocene (2). Coal characterization and washability studies were performed on all coal samples by the Mineral Industry Research Laboratory of the University of Alaska Fairbanks. This work was conducted under the direction of Dr. P.D. Rao, Professor of Coal Technology.
    • Characterization of Alaska North Slope oils for wax deposition

      Anyanwu, Okechukwu Ndubuisi; Zhu, Tao; Chukwu, Godwin A.; Dandekar, Abhijit; Zhou, Wendy (2007-08)
      Wax deposition during crude oil production is a major problem that has plagued the oil industry for decades especially in cold environments such as Alaska North Slope (ANS) fields, with adverse consequences in huge mitigation cost and lost production. It is therefore imperative to adequately and accurately identify the conditions for wax precipitation and deposition in order to optimize operation of the production systems of ANS. In order to assess ANS crude's potential for wax precipitation, Viscometry and Cross Polarization Microscopy (CPM) are used to determine the temperature at which paraffins begin to precipitate from ANS dead oils. Wax dissolution temperatures (WDT) are also determined by CPM. Results show that wax precipitation is possible at temperatures as high as 41°C (106°F) while it takes up to 50°C (122°F) to get all waxes back into solution. The CPM technique was more sensitive while Viscometry results did not provide a high level of certainty in some samples and therefore appear over-estimated relative to CPM results. Previous thermal history was observed to influence test results. Pour point, viscosity, density and specific gravity have also been measured. Pour point results indicate that oil could form gel in the temperature range 12°C (53.6°C) to less than -31°C ( -23.8°F).
    • Characterization of Alaska's coals

      Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1974)
      Coal characterization is a systematic determination of those properties of coal, or of its constituents, that affect its behavior when used. It will help in planning for recovery and use of the extensive Alaskan coal deposits, which have proven reserves of 130 billion tons. This estimate is of necessity based on widely scattered outcrops and meager drill hole data, and the reserves in the Cook Inlet region and the Northern Alaska field are considered to be several fold this figure.
    • Characterization of Alaskan HMA Mixtures with the Simple Performance Tester

      Li, Peng; Liu, Juanyu (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2014)
    • Characterization of Alaskan Hot-Mix Asphalt containing Reclaimed Asphalt Pavement Material

      Liu, Jenny; Zhao, Sheng; Li, Lin (Center for Environmentally Sustainable Transportation in Cold Climates, 2016-06)
      In order to properly characterize Alaskan HMA materials containing RAP, this study evaluated properties of 3 asphalt binders typically used in Alaska, PG 52-28, PG 52-40, and PG 58-34, and 11 HMA mixtures containing up to 35% RAP that were either produced in the lab or collected from existing paving projects in Alaska. Various binder and mixture engineering properties were determined, including true high binder grades, complex modulus (|G*|), and phase angle (δ) at high performance temperatures, MSCR recovery rate and compliance, BBR stiffness and m-value, DTT failure stress and strain for binders, and dynamic modulus, flow number, IDT creep stiffness and strength for mixtures. Binder cracking temperatures were determined through Thermal Stress Analysis Routine (TSAR) software along with BBR and DTT data. Mixture cracking temperatures were determined with IDT creep stiffness and strength data. It was found that rutting may not be a concern with Alaskan RAP mix, while low-temperature cracking concerns may still exist in RAP mix in Alaska. A savings of $13.3/ton was estimated for a 25% RAP mix, with consideration of Alaskan situations. Many recommendations for future RAP practice and research are recommended based on testing results and cost analysis.
    • Characterization of Asphalt Treated Base Course Material

      Li, Peng; Liu, Juanyu (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2010)