Recent Submissions

  • Investigation of nanoscale drug particles and their effect on the fluid dynamic properties of the blood

    Slats, Jason L.; Das, Debendra; Zhang, Lei; Misra, Debasmita (2020-05)
    Research has shown that gold nanoparticles increase the efficiency of radiation treatments of cancer by up to 25%. This means patients can be exposed to lower doses of radiation that does more concentrated damage to cancerous cells and less damage to healthy surrounding tissue. Before these nanoparticles can be introduced to the human body, the behavior of these particles in the blood stream must be understood. A model of gold nanoparticle flow through the aortic arch was developed in the present investigation for predicting behavior of these particles in the human body. A set of initial modeling parameters was developed out of existing data pertaining to blood flow rates and viscosities of a blood-mimicking fluid across a temperature range of 30-40 degrees Celsius. The aorta wall was modeled as a no-slip solid surface. Computational fluid dynamic models using ANSYS Fluent across this temperature range have generated general velocity distributions of blood flow through the aortic arch and identifies several areas of possible recirculation. The current state of the model provides preliminary results, which are valuable in generating an accurate model of gold nanoparticles flowing through the aortic arch.
  • MIL-53 (Al) and graphene oxide nanocomposites for dye adsorption

    Serventi, Daniel R; Zhang, Lei; Peterson, Rorik; Zhang, Junqing; Huang, Daisy (2020-05)
    Textile manufacturers produce large amounts of wastewater every year as a result of global demand. Waste dyes are highly resilient against physical processes, insoluble in water, and resistant to detergents. Carcinogenic and mutagenic effects are linked to these dyes, making them a large health hazard. Current dye removal methods are highly complex and inefficient. Thus, a new means of removing textile dyes from wastewater is needed. Nanomaterials are one such possibility, since they exhibit traits unique from bulk materials. One key trait is their surface area to volume ratio. Since the materials are so small, they’re almost able to be considered two dimensional in certain instances. A high surface area is closely linked to adsorption potential, making nanomaterials a promising candidate for dye removal. This project has two portions: material synthesis and adsorption testing. Material synthesis sets up the adsorption testing phase by fabricating enough nanomaterials for testing. The nanomaterials used for this project are MIL-53 (Al) and graphene oxide (GO). MIL-53 (Al) and GO were chosen since they exhibit good stability in water and effective geometrical structures for water filtration. Synthesized composites of the two materials varying in mass of GO will be tested as well. Adsorption testing uses slightly acidic (pH 5.6) methyl blue and methyl orange solutions of varying parts per million (PPM) concentrations. The tests examine effects of initial concentration, duration of exposure, and temperature effects on adsorption potential. Nanomaterials reached equilibrium adsorption after 12 hours of mixing. Most materials efficiently removed up to 90% or greater of dye particles in solutions with initial concentrations of 100 PPM for both dye colors. Increased temperatures reduced adsorption potential of nearly all materials tested for both dye colors.
  • Analysis of ground source heat pumps in sub-Arctic conditions

    Bishop, Stephen; Peterson, Rorik; Daanen, Ronald; Shur, Yuri (2014-05)
    The Purpose of this project is to investigate the factors involved in the application of a ground source heat pump in subarctic conditions. This project originated with the construction of a ground source heat pump (GSHP) built at Cold Climate Housing Research Center's (CCHRC) Research Testing Facility. The GSHP built by CCHRC is an experiment to test the viability of a GSHP with different surface coverings. Specifically, this project will focus on different soil and atmospheric properties to gauge their effect on a GSHP in sub-arctic conditions. The project is primarily broken into 3 main sections which test in simulation: the effects of soil and atmospheric properties on heat flow into soil, the effects of these properties on a hypothetical GSHP and applying this to a simulation of CCHRC's GSHP. Additionally, some mitigation efforts were attem pted in simulation to improve the viability of the GSHP built by CCHRC.
  • Corrosion behavior of titanium dioxide (TiO₂)-coated Al alloy in saline environment

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

    Wright, Zackery; Huang, Daisy; Nicholls, David; Peterson, Rorik; Schnabel, William (2016-05)
    Biomass energy has been a topic of great interest over the previous few years in Alaska; especially when various fuel sources were priced at a record high. Interior Alaska has the potential to utilize woody biomass to offset the use of coal in many of its power generating facilities. In this study, woody biomass in the form of clean aspen (Populus tremuloides) chips was cofired with Usibelli coal at the Aurora Power Plant facility in downtown Fairbanks, Alaska. Biomass was successfully cofired at low average rates of 2.4% and 4.81% of total energy value. Combustion gasses were analyzed using measuring probes in the exhaust stack. The 2.4% biomass test saw, on average, an increase in CO and CO₂ by 95ppm and 2%, respectively. A decrease in NOx of 1ppm was observed. During the 4.81% biomass test, CO increased by 83ppm, NOx decreased by 18ppm, and CO decreased by 1%. Opacity increased by 0.1% during the 2.4% biomass test and 0.17% during the 4.81% biomass test. The challenges facing a small scale facility in Interior Alaska are also presented. The testing exemplified that the use of biomass in stoker/grate boilers in Alaska is technically feasible with relative ease. No technical barriers to cofiring at low levels on an on-going basis were found at the Aurora Power Plant and this conclusion would likely hold true at similar facilities in interior Alaska.
  • Volumetric heat transfer via constructal theory, and its applications in permafrost and hydrogen energy storage

    Kukkapalli, Vamsi Krishna; Kim, Sun Woo; Lin, Chuen-Sen; Das, Debendra (2016-05)
    Constructal theory is widely used as a powerful tool in designing of engineering systems (flow configurations, patterns, geometry). This theory is observed in nature and its principles are applicable to general engineering. Constructal theory encompasses a wide range of space in the "design", drawing from each and every field from engineering to biology. The universal design of nature and the constructal law unify all animate schemata such as human blood circulatory systems, and inanimate systems, such as urban traffic and river basins. The proceeding research applies the overlying theories of constructal theory to the two different systems in order to achieve best thermal performance phenomena. The first is stabilization of roadway embankments in the permafrost regions with design modifications in existing thermosyphon evaporators with tree structure designs, and defining the optimal spacing between two neighboring thermosyphons based on thermal cooling phenomena. This research utilizes constructal law to the generation of tree-shaped layouts for fluid flow, so that the flow structures use the available space in optimally. The intention here is the optimization of geometry of the flow system. This begins with the most simple cases of tree-shaped flows: T- and Y-shaped constructs, the purpose of which is to create a flow connection between one point (defined as a "source" or "sink") to an infinity of points (via a line/area/volume). Empirically speaking, tree-shaped flows are natural examples of selforganization and optimization. By contrast, constructal law is theory which states that flow architectures such as these are the evolutionary results of nature which tend toward greater global flow access. Tree-shaped flows can be derived from this constructal law. The mathematical simulation revealed that there exists an optimal spacing between two neighboring thermosyphons, and the tree structures perform better than the existing configuration in terms of thermal cooling. The second part of the research is to find an effective way to reject heat released from the metal hydride powder to the outer environment during the hydrogen absorption process. The main objective of this investigation is to minimize the time required for the absorption process, and to reduce the hotspot temperature by determining the optimal aspect ratio of rectangular fins, while the total volume of fins used is kept constant. The intension of using constructal theory in this part of research is to find the optimal geometrical parameters (length, width) of the fin structure for better thermal performance of the metal hydride reactor system. The simulations revealed that there exists an optimum aspect ratio of rectangular fins for accelerating heat rejection and lowering the hotspot temperature in a cylindrical metal hydride reactor. Constructal theory is supremely adapted for use in 2-dimensional and 3-dimensional design for heat transfer structures, as it allows for incorporation of minute analysis of the interior structure with the goal of optimizing for heat transfer. In its application in the realm of engineering, every multidimensional solid structure that is to be cooled, heated or serviced by fluid streams must be vascularized. By this definition, 'vascularization' includes, however is not limited to, structures such as trees, geometrical spacing, and solid walls. Here, every geometric detail will be sized and positioned to achieve maximum efficacy from an engineering design point of view. Furthermore, via design morphing we can achieve low resistances in flow structures which are applicable in cooling and heating applications. An example is that of a ground-source heat pump design where the piping design is morphed by constructal law and spaced in an optimal way to achieve maximum thermal efficiency when extracting heat from the ground.
  • Exhaust thimble for arctic environments

    Evans, Mark P.; Peterson, Rorik; Kim, Sun woo; Lin, Chuen-Sen (2016-05)
  • Latching mechanism between UAV and UGV team for mine rescue

    Hoffman, Sarah; Peterson, Rorik; Hatfield, Michael; Lin, Chuen-Sen (2017-08)
    Safety is a concern in the mining industry when a tunnel collapse could result in the casualties and deaths of workers and rescuers due to the hazards posed to them. The Alaska Center for Unmanned Aircraft Systems Integration (ACUASI) is working on a project to increase mine safety by sending an Unmanned Ground Vehicle (UGV) fit with LiDAR sensors and an Unmanned Aircraft Vehicle (UAV) to map the tunnels and to find a collapsed tunnel in an effort to determine the location and condition of trapped workers. The UGV will drive to the collapsed tunnel, at which point the U AV will launch to find any gap in the tunnel that it could fly through to assess the damage. This overall project requires a releasing and latching system to secure the UAV, allow it to launch at the appropriate location, and dock the UAV when its mission is complete or its battery needs recharging. A simple pin-through design was adopted to latch and release the UAV by implementing a Scotch yoke and servo as the actuator. All necessary components were analyzed for stress using two forces, 16 N (maximum takeoff weight of the potential UAV) and 150 N (im pact force of the maximum w eight of the potential UAV from 0.15 m or just under 6 inches). Three sets of properties for PLA were applied in the stress analyses to thoroughly investigate the feasibility of creating the parts out of PLA, a commonly used plastic for 3D printing. These three property sets were found in literature and consisted of bulk values of PLA, empirically determined values of 3D printed PLA, and values calculated using porosity equations. It was found that most components would function satisfactorily without risking fracture except in extreme conditions. The stress analyses for the landing gear illustrated its weaknesses, revealing a potential need for a different material or redesign. The landing gear as it is could be utilized under nominal operation, but it could not withstand any significant impact such as one that might occur in the event of a hard landing. The latching mechanism itself succeeded in securing the UAV. Future work includes redesigning the landing gear, another design concept for a latching mechanism that may prove more reliable, and adjusting the landing pad in the event a different UAV is selected.
  • TEST Master's Projects 9/25/17

    CHISUM (2017-09)
    TEST Master's Projects 9/25/17