• Economic and Organizational Issues in Alaska Water Quality Management

      Erickson, Gregg K.; Tussing, Arlon R. (University of Alaska, Institute of Water Resources, 1971-09)
    • An economic appraisal of hole cleaning using hydraulic horsepower and jet impact force

      Wright, James Alfred (2001-12)
      In today's competitive business environment, reducing operating cost means dollars to the bottom line. One way that a drilling company can reduce operating cost is by optimizing energy use at the mud pumps. The mud pumps are massive pieces of equipment that are the backbone of the cutting's removal system. Optimizing the hydraulics program is one way to reduce mud pump operating cost. Big hydraulics play an important role in the drilling process. The beneficial action of the fluid's cleaning the bottom hole and the bit teeth, and carrying particles into the annulus is well-established. A variety of hydraulic optimization designs are available, however, in this study the efficiency and cost effectiveness of two methods are compared: Jet Impact force and Hydraulic Horsepower. Both methods have a fundamental objective to maximize the available hydraulics to provide optimum cleaning but Jet Impact method optimizes drilling cost better than Hydraulic Horsepower.
    • Economic assessment of Alaska North Slope hydrate-bearing reservoir regional production development schemes

      Nollner, Stephanie P.; Dandekar, Abhijit; Patil, Shirish; Ning, Samson; Khataniar, Santanu (2015)
      The objective of this project was to evaluate the economic feasibility of producing the upper C sand of the Prudhoe Bay Unit L Pad gas-hydrate-bearing reservoir. The analysis is based on numerical modelling of production through depressurization completed in CM G STARS by a fellow UAF graduate student, Jennifer Blake, (2015). A staged field development plan was proposed, and the associated capital and operating costs were estimated using Siemens's Oil and Gas Manager planning software and costing database. An economic assessment was completed, incorporating the most common royalties, the current taxes laws applicable to conventional gas development, and most recent tariff estimates. The degree of vertical heterogeneity, initial average hydrate saturation, well spacing and well type had a significant impact on the regional gas production profiles in terms of cumulative volume produced, and more importantly, the expediency of gas production. The volume that is economically recoverable is highly dependent on how the field is developed. A field that has higher vertical heterogeneity and corresponding lower average initial hydrate saturation is most economically produced using horizontal wells at 160 acre spacing; the acceleration of gas production outweighs the increased drilling costs associated with the longer wells and tighter well spacing. The choice of development scenario does not impact the project economics significantly given a field that has lower vertical heterogeneity; however, development using horizontal wells at 320 acre spacing is marginally more economic than the alternatives. Assuming a Minimum Attractive Rate of Return of 20%, the minimum gas price that would allow economic production of ANS gas hydrates was found to be $29.83 per million British thermal units; this value is contingent on the reservoir having high average initial hydrate saturation and being developed with horizontal wells at 320 acre spacing. A slightly higher gas price of $36.18 per million British thermal units would allow economic production of a reservoir having low average initial hydrate saturation that is developed with horizontal wells at 160 acre spacing.
    • Economic evaluation of gas to liquids (GTL) product transportation through the Trans Alaska Pipeline Systems (TAPS)

      Ejiofor, Nkemakonam (2003-05)
      The Alaska North Slope is a potential candidate for the Gas to Liquid (GTL) technology. With over 38 Tcf of natural gas reserves stranded on the Alaska North Slope, the GTL technology is considered as a possible method of harnessing the abundant resources. GTL fuels are environmentally friendly (sulfur free) with better ignition and burning properties than conventional petroleum products from crude oil. Evaluating the options of transporting GTL products through the existing Trans Alaska Pipeline System (TAPS) together with crude oil either as a blend of crude oil and GTL (commingled) or as alternate slugs of each product (batching) is the main focus of this study. Economic evaluation using Rate of Return analysis to identify the most favorable mode of transportation of the GTL products was performed. Batching, using the modem tracking and sensor techniques was found to be the most economic method yielding the highest return on investment.
    • Economic evaluation of gas to liquids (GTL), crude oil commingled product transportation through the Trans Alaska Pipeline System (TAPS)

      Ibironke, Adejoke Motunrayo; Patil, Shirish L.; Chukwu, Godwin A.; Khataniar, Santanu A.; Reynolds, Douglas B.; Dandekar, Abhijit (2004-12)
      The Alaska North Slope is a potential candidate for the Gas to Liquid (GTL) technology. With over 38 TCF of natural gas reserves stranded on the Alaska North Slope, the GTL technology is considered as a possible method of harnessing the abundant resources. GTL fuels are environmentally friendly (sulfur free) with better ignition and burning properties than conventional petroleum products from crude oil. Economic evaluation using Rate of Return analysis and the Net Present Value (NPV) to identify the most favorable commingled mode for the transportation of the GTL products was performed. The Crystal Ball software was also used to run sensitivity analysis by using the probabilistic approach to give a clear view of the various scenarios on the project economics. Evaluating the options of transporting GTL products as a blend (Commingled) with the Alaska North Slope Crude Oil through the existing Trans-Alaska Pipeline System (TAPS) is the main focus of this study.
    • Economics of gas to liquids technology for monetization of Alaska North Slope Natural gas reserves

      Ogugbue, Chinenye C. E.; Chukwu, Godwin A.; Khataniar, Santanu; Patil, Shirish; Dandekar, Abhijit Y. (2006-08)
      The proven natural gas reserves of the Alaska North Slope (ANS) have enormous potential as clean-burning energy resources, if they can be effectively and efficiently utilized. These gas resources, exceeding 35 trillion cubic feet (TCF), currently represent a significant proportion of the energy equivalence of proven ANS oil reserves. With ANS located far from potential markets, there is need to evaluate the prospective economics of promising technologies for monetization of these stranded gas reserves. The economics of the chemical conversion of natural gas to synthetic liquid fuels favored by recent advances in FT synthesis techniques, liquid fuel transportation for the Trans Alaskan Pipeline System (TAPS) operations, and increased demand for clean burning diesel fuels, was the main focus of this study. Economic evaluation using Internal Rate of Return (IRR) analysis, Payout Time and the Net Present Value (NPV) to access and compare the economic viability of 3-train and 4-train GTL Projects is performed. Monte-Carlo simulation using the Crystal Ball software was utilized to run sensitivity analysis, incorporating the probabilistic approach, which generated insightful scenarios on the project economics.
    • The effect of capillary pressure on methane gas recovery from gas hydrates: a simulation study

      Stone, Christopher L. (2006-05)
      A simulation study on the effects of capillary pressure on methane gas recovery from methane hydrates was conducted using STOMP-HYD. Four stimulation recovery methods were examined in the study; thermal stimulation, depressurization above the Q-point, depressurization below the Q-point, and CO₂ micro-emulsion injection. Van Genuchten parameters pertaining to moisture retention characteristics for soil types ranging from coarse to fine grained were introduced into the simulations to quantify what role capillary force plays in methane gas recovery. It was observed that greater capillary forces resulted in gas production occurring sooner in all four stimulation cases. It was found that greater aqueous saturations resulted due to the higher capillary forces. The greater aqueous saturation allow for greater heat transfer through the porous media. As a result of greater heat transfer, CH₄ hydrates dissociate sooner in the cases where high capillary forces were observed, lending to faster production rates.
    • The Effect of Load History on Reinforced Concrete Bridge Column Behavior

      Goodnight, Jason; Feng, Yuhao; Kowalsky, Mervyn; Nau, James (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2012)
    • Effect of Radiant Barriers in Wall Construction

      Estes, Mark; Olson, Todd (1988-01)
      The performance of radiant cardboard barriers were tested and evaluated using the DOT&PF guarder hot box. Two types of insulation were used in the testing fiberglass bat and blown cellulose. The test procedure consisted of obtaining temperature measurements at designated positions throughout seven types of wall configurations. These tests showed, that the configuration with 5.5 inches of fiberglass bat insulation compressed to 4 inches with a radiant cardboard barrier allowed the least total heat flux through the wall section. An economic analysis indicated that the use of radiant barriers may be feasible in situations where insulation support is needed or an uninsulated gab is required for wiring or utilities.
    • Effect of Waste Discharges into a Silt-laden Estuary: A Case Study of Cook Inlet, Alaska

      Murphy, R. Sage; Carlson, Robert F.; Nyquist, David; Britch, Robert (University of Alaska, Institute of Water Resources, 1972-11)
      Cook Inlet is not well known. Although its thirty-foot tidal range is widely appreciated, its other characteristics, such as turbulence, horizontal velocities of flow, suspended sediment loads, natural biological productivity, the effects of fresh water inflows, temperature, and wind stresses, are seldom acknowledged. The fact that the Inlet has not been used for recreation nor for significant commercial activity explains why the average person is not more aware of these characteristics. Because of the gray cast created by the suspended sediments in the summer and the ice floes in the winter, the Inlet does not have the aura of a beautiful bay or fjord. The shoreline is inhospitable for parks and development, the currents too strong for recreational activities, and, because of the high silt concentration, there is little fishing. Yet, Cook Inlet, for all its negative attributes, can in no way be considered an unlimited dumping ground for the wastes of man. It may be better suited for this purpose than many bays in North America, but it does have a finite capacity for receiving wastes without unduly disturbing natural conditions. This report was written for the interested layman by engineers and scientists who tried to present some highly technical information in such a manner that it could be understood by environmentalists, concerned citizens, students, decision makers, and lawmakers alike. In attempting to address such a diverse audience, we risked failing to be completely understood by any one group. However, all too often research results are written solely for other researchers, a practice which leads to the advancement of knowledge but not necessarily to its immediate use by practicing engineers nor to its inclusion in social, economic, and political decision-making processes. We hope this report will shorten the usual time lag between the acquisition of new information and its use. Several additional reports will be available for a limited distribution. These will be directed to technicians who wish to know the mathematical derivations, assumptions, and other scientific details used in the study. Technical papers by the individual authors, published in national and international scientific and engineering journals, are also anticipated.
    • The Effectiveness of a Contact Filter for the Removal of Iron from Ground Water

      Kim, Steve W. (University of Alaska, Institute of Water Resources, 1971-01)
      Various types of modified filters were investigated to replace greensand filters which clogged when removing ground water. A properly designed uniform-grain sized filter can increase the filtration time more than ten times that of ordinary sand or greensand filters. The filter medium was obtained by passing commercial filter material between two standard sieves of a close size range, so that the resulting medium was of a uniform size. The head loss rate on such a medium was independent of the filter depth and was inversely proportional to the almost 3/2 power of the grain size. On the other hand, the filter depth was almost linearly proportional to the time of protective action. The effects of the grain size, filter depth, and filter material on the filter run were evaluated with a synthetic iron water; and optimum filter depths for each unisized material were determined. At identical filtration conditions, anthracite had a 70 to 110% longer filter run than the sand medium, and it was attributed to the greater porosity of the former. Expectedly, the time to reach initial leakage of the iron floc was greater with the coarse and more porous medium. but was reduced to an insignificant amount when the filter depth was increased to three to six feet. The performance of unisized filters on permanganate-treated ground water was much better than that of fine-grained greensand. Applicability of experimental data on an existing filtration theory was investigated
    • Effects of electromigration on the reliability of radio frequency microelectro mechanical switches

      Karri, Naveen Kishore (2004-12)
      Radio Frequency (RF) Micro-Electro-Mechanical System (MEMS) switches have many advantages over semiconductor switches. Despite these advantages they are not implemented in reliability demanding space, defense and commercial applications because of reliability concerns. Although some failure modes have been identified so far, other failure modes are still under research. Electromigration, a well-known failure mechanism in interconnects, was recently recognized as a possible cause of failure in micro-switches. However, there have been no instances of electromigration studies in the literature. This thesis presents a preliminary study on the electromigration failure and its impact on the lifetime of MEMS switches. A simulation program that emulates the electromigration process was developed. Parametric studies were performed to study the impact of impact certain parameters on electromigration process. The combined effects of Joule heating and electromigration were analyzed. Unlike passivated interconnects, the micro-switch is cantilevered and suspended in an inert medium without encapsulation. The electromigration lifetime estimation program developed in this thesis is applicable to all such free structures. Joule heating has been demonstrated to be a key factor in the electromigration failure of micro-switches. Results showed that the electromigration process is very slow at the beginning. After a certain time, the resistance is found to increase exponentially, increasing the temperature of the strip drastically toward failure. The same trend is also observed in a gold micro-switch, but with much slower rate of electromigration degradation, indicating a longer lifetime.
    • The Effects of Extreme Floods and Placer Mining on the Basic Productivity of Sub Arctic Streams : A Completion Report

      Morrow, James E. (University of Alaska, Institute of Water Resources, 1971)
      The original proposal for this project was submitted to OWRR in the fall of 1967 and envisioned a two year investigation involving the principal investigator and three graduate student assistants, with a first year budget of nearly $25,000.00. However, the project was approved for only one year, with a total budget of $5,757.00. In addition, even these funds did not become available until August 1968. Because of the lateness of availability and the sharp curtailment of the total amount, it was not possible to purchase any equipment. Hence, measurements of rainfall, current velocity, basic productivity, etc., had to be abondoned. All that could be done was to acquire data on the bottom fauna and some physico-chemical characteristics of the water.
    • The Effects of Load History and Design Variables on Performance Limit States of Circular Bridge Columns

      Goodnight, Jason Chad; Feng, Yuhao; Kowalsky, Mervyn J.; Nau, James M. (2015-01)
      This report discusses a research program aimed at defining accurate limit state displacements which relate to specific levels of damage in reinforced concrete bridge columns subjected to seismic hazards. Bridge columns are designed as ductile elements which form plastic hinges to dissipate energy in a seismic event. To satisfy the aims of performance based design, levels of damage which interrupt the serviceability of the structure or require more invasive repair techniques must be related to engineering criteria. For reinforced concrete flexural members such as bridge columns, concrete compressive and steel tensile strain limits are very good indicators of damage. Serviceability limit states such as concrete cover crushing or residual crack widths exceeding 1mm may occur during smaller, more frequent earthquakes. While the serviceability limit states do not pose a safety concern, the hinge regions must be repaired to prevent corrosion of internal reinforcing steel. At higher ductility demands produced by larger less frequent earthquakes, reinforcing bar buckling may lead to permanent elongation in the transverse steel, which diminishes its effectiveness in confining the concrete core. Bar buckling and significant damage to the core concrete represent the damage control limit states, which when exceeded lead to significant repair costs. Furthermore, rupture of previously buckled bars during subsequent cycles of loading leads to rapid strength loss. The life safety or collapse prevention limit state is characterized by fracture of previously buckled bars. The goal of the experimental program is to investigate the impact of load history and other design variables on the relationship between strain and displacement, performance strain limits, and the spread of plasticity. The main variables for the thirty circular bridge column tests included: lateral displacement history, axial load, longitudinal steel content, aspect ratio, and transverse steel detailing. A key feature of the experiments is the high fidelity strain data obtained through the use of an optical 3D position measurement system.Column curvature distributions and fixed-end rotations attributable to strain penetration of reinforcement into the footing were quantified. The following sequence of damage was observed in all of the cyclically loaded experiments: concrete cracking, longitudinal steel yielding, cover concrete crushing, confinement steel yielding, longitudinal bar buckling, and fracture of previously buckled reinforcement. The first significant loss in strength occurred when previously buckled reinforcement fractured. The measured data was used to refine strain limit recommendations. Particular attention was paid to the limit state of longitudinal bar buckling, since it limited the deformation capacity of all of the cyclically loaded specimens. Empirical expression were developed to predict the compressive strain at cover crushing, the compressive strain at spiral yielding, and the peak tensile strain prior to visible buckling after reversal of loading. In design, limit state curvatures are converted to target displacements using an equivalent curvature distribution. The Modified Plastic Hinge Method was developed to improve the accuracy of strain-displacement predictions. Key aspects of the proposed model which differentiate it from the current method include: (1) a decoupling of column flexure and strain penetration deformation components, (2) a linear plastic curvature distribution which emulates the measured curvature profiles, and (3) separate plastic hinge lengths for tensile and compressive strain-displacement predictions. In the experiments, the measured extent of plasticity was found to increase due to the combined effects of moment gradient and tension shift. The proposed tension hinge length was calibrated to match the upper bound of the measured spread of palsticity. The proposed compressive hinge length only contains a term related to the moment gradient effect. Expressions which describe the additional column deformation due to strain penetration of reinforcement into the adjoining member were developed. When compared to the current technique, the Modified Plastic Hinge Method improved the accuracy of both tensile and compressive strain-displacement predictions. Abstract for Volume 3: This report presents the numerical portion of the research project on the impacts of loading history on the behavior of reinforced concrete bridge columns. In well-detailed reinforced concrete structures, reinforcing bar buckling and subsequent bar rupture serve as common failure mechanisms under extreme seismic events. Engineers often use a strain limit state which is associated with bar buckling as the ultimate limit state, but the relationship between the strain demand and resultant bar buckling is not well understood. Past research has indicated large impact of the cyclic loading history on the strain demand to achieve reinforcing bar buckling. On the other hand, sectional analysis is widely implemented by engineers to relate strain to displacement. However, the cyclic load history also has potential impact on the relationship between strain limits and displacement limits. As a result, it is important to study the seismic load history effect on the strain limit state of reinforcing bar buckling and on the relationship between local strain and structural displacement. In addition, Performance-Based Earthquake Engineering (PBEE) strongly depends on an accurate strain limit definition, so a design methodology needs to be developed to identify the strain limit for reinforcing bar buckling including the seismic load history effect. Two independent finite element methods were utilized to accomplish the goal of this research work. First, fiber-based analysis was utilized which employed the Open System for Earthquake Engineering Simulation (OpenSees). The fiber-based method was selected because of its accuracy in predicting strains and its computational efficiency in performing nonlinear time history analysis (NTHA). The uniaxial material models in fiber-based sections were calibrated with data from material tests. In addition, strain data and force-deformation response from large scale testing assists selection of element types and integration schemes to ensure accuracy. The advanced beam-column elements and material models in OpenSees resulted in a very accurate prediction of strain at local sections as well as global dynamic response of structures. A number of nonlinear time history analyses with 40 earthquake ground motions were conducted to investigate the effect of seismic load history on relationship between structural displacement and strain of extreme fiber bars at the critical section. The second finite element model was established with solid elements to predict bar buckling. The model included a segment of reinforcing bar and its surrounding elements, such as spiral turns and concrete. This model separates itself from previous bar buckling research by utilizing actual sectional detailing boundary conditions and plastic material models instead of the simplified bar-spring model. The strain history is considered as the demand on this model. A series of strain histories from the experimental tests and fiber-based analyses were applied to the finite element model to study their impacts on the strain limit for reinforcing bar buckling. Initial analytical investigations have shown significant impact of load history on the strain demand to lead to reinforcing bar buckling in the plastic hinge region. This is also confirmed in the experimental observation which only included a limited number of load histories. The parametric study extended the range of load history types and also studied the effect of reinforcement detailing on bar buckling. On the other hand, analyses with fiber-based models showed that the load history rarely impacts the relationship between local strain and structural displacement. A design approach was developed to include the load history effect on the strain limit state of bar buckling.
    • Effects of Permafrost and Seasonally Frozen Ground on the Seismic Response of Transportation Infrastructure Sites

      Yang, Zhaohui Joey; Dutta, Utpal; Xu, Gang; Hazirbaba, Kenan (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2010)
    • The effects of placer mining on the environment in Central Alaska

      Wolff, E.N.; Thomas, B (University of Alaska Mineral Industry Research Laboratory, 1982)
      Within the Tolovana Mining District, as a result of placer mining, 800 acres of land have been disturbed (0.25% of the land area) and 4 million cubic yards of much have been transported down the Tolovana River through the subsiding Minto Flats. This has increased the rate of sedimentation of the lakes adjacent to the Tolovana River. Mine tailings are about 50% revegetated by natural species. Approximately 60 million cubic yards of muck must be removed to mine the Livengood deposits. A large area of settling ponds will be needed if the deposit is stripped by hydraulic means, or a large area for stacking overburden if mechanical stripping is required. The Crooked Creek area, mined for 80 years has 1,900 acres disturbed (0.7% of the land area) and 200,000 cubic yards of much has been stripped. No correlation is apparent between mining and the non-anadromous fish population, although sport fishing is considered by some to be not as good as a result of mining. Portions of the stream system observed to be impacted with mud showed evidence of having been periodically flushed out. Slave analysis and trace element analysis were applied in an attempt to trace sediments back to their sources, but were not successful. Mining is the pioneer industry around which much of the State of Alaska developed. The transportation network required by the mining industry benefits sportsmen, the tour industry, and directly increases the value of adjacent land. The profit from mining brought much of the early population to the state, and will be a steady source of revenue in years to come.
    • Effects of Reading Text While Driving: A Driving Simulator Study

      Prevedouros, Panos; Miah, M. Mintu; Nathanail, Eftihia (2020-02)
      Although 47 US states make the use of a mobile phone while driving illegal, many people use their phone for texting and other tasks while driving. This research project summarized the large literature on distracted driving and compared major outcomes with those of our study. We focused on distraction due to reading text because this activity is most common. For this research project, we collected simulator observations of 203 professional taxi drivers (175 male, and 28 female) working at the same Honolulu taxi company, using the mid-range driving simulator VS500M by Virage. After a familiarization period, drivers were asked to read realistic text content relating to passenger pick up displayed on a 7-inch tablet affixed to the dashboard. The experimental scenario was simulated on a two-lane rural highway having a speed limit of 60 mph and medium traffic. Drivers needed to follow the lead vehicle under regular and text-reading conditions. The large sample size of this study provided a strong statistical base for driving distraction investigation on a driving simulator. The comparison between regular and text-reading conditions revealed that the drivers significantly increased their headway (20.7%), lane deviations (354%), total time of driving blind (352%), maximum duration of driving blind (87.6% per glance), driving blind incidents (170%), driving blind distance (337%) and significantly decreased lane change frequency (35.1%). There was no significant effect on braking aggressiveness while reading text. The outcomes indicate that driving performance degrades significantly by reading text while driving. Additional analysis revealed that important predictors for maximum driving blind time changes are sociodemographic characteristics, such as age and race, and past behavior attributes.
    • Effects of Reservoir Clearing on Water Quality in the Arctic and Subarctic: Completion Report

      Smith, Daniel W.; Justice, Stanley R. (University of Alaska, Institute of Water Resources, 1975-01)