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Development of OpenStudio model for CLT hotelCross-laminated timber (CLT), a type of mass timber in which wood is secured in alternating directions, has emerged as an sustainable alternative to concrete or steel with a significantly lower carbon footprint. However, CLT properties depend on its moisture content and most building energy tools do not account for moisture transfer in building envelopes. This study develops a building energy modeling in OpenStudio for a hotel in Fort Jackson, North Carolina, that utilizes CLT to compare against field data. When the data is collected from the hotel, the OpenStudio model will be calibrated to the measurements so that future models can more accurately predict the properties of the building envelope in CLT buildings.
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Mathematical modeling to investigate dual pathway inhibition by anticoagulant and antiplatelet drugsThe purpose of blood coagulation is to halt blood flow from a damaged vessel for the vessel to heal and repair. Blood coagulation occurs as overlapping enzymatic events, which are strongly regulated by platelet surfaces. Coagulation begins when the wall of the blood vessel is injured and ends when aggregated platelets seal the injury. Dual pathway inhibition, in which both antiplatelet and anticoagulant drugs are used in combination, promises therapies for reducing risks of harmful clot development that may lead to coronary and cerebrovascular ischemia. Although information exists concerning the effectiveness and success of dual pathway inhibition therapies, the mechanism remains ambiguous due to a lack of ability to observe detailed biochemical interactions during the dynamic clotting process. Mathematical modeling allows for efficient simulations of the clotting process and provides access to the dynamic concentrations of all proteins, cells, and interactions within the system under the influence of flow. This project builds on a mechanistic mathematical model of flow-mediated coagulation and platelet deposition. A combination of the antiplatelet aspirin and the anticoagulant rivaroxaban is considered in the model, and the clotting process is simulated for various concentrations of drugs and injury types.
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The social impacts of the Gold King mine spill: an interdisciplinary approachOn August 5th, 2015, 3 million gallons of mustard-yellow mine wastewater was unleashed onto Cement Creek, the Animas River, and eventually the mighty San Juan river. In the days, weeks, and months that followed, a glaring question presented itself. Who's to blame? The event brought up long-existing problems and questions about the state of water quality in the San Juan mountains. In this study, we focus on the perspective of 3 of the biggest agents: the town of Silverton, the city of Durango, and the Navajo Nation. Each of these actors have an independent newspaper which presents a valuable look into how the local community perceived this event. By analyzing keywords, impactful quotes, and unique phrasing, we were able to gauge the response to each community over time. According to a preliminary sample of the Durango Herald (Durango's local newspaper), the EPA was the primary group blamed for the spill with no one at fault being the next largest group. This can help us contextualize Durango and La Plata County when comparing this to other impacted areas and historical information. By analyzing the local newspapers in impacted areas, we are able to gain a better idea of both the local impact and perception of the event, leading to more objective, educated understanding of the catastrophe.
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Nanoscale rock-salt structured high-entropy metal oxides for catalysisHigh-entropy materials are a new class of solids that are rapidly growing in scientific interest differ because they are formed and stabilized by the large configurational entropy generated by their multi-elemental composition. Due to the large range of possible multi-elemental configurations, it is possible to tune the chemical and physical properties for specific electronic and catalytic purposes. The focus of this research is the wet chemical synthesis and characterization of nanoscale high-entropy metal oxides with a rock-salt structure. Specifically, this research focuses on high-entropy oxide nanomaterial catalysts that are made from earth-abundant and inexpensive precursor metals. Although there have been recent reports regarding very interesting catalytic properties, the ability to control the structure of this class of materials on the nanoscale remains a challenge. If this class of materials can be tailored in terms of both composition and nanoscale morphology, they offer a path using earth abundant systems to replace current catalytic materials which are generally rare and expensive metals such as platinum, iridium, and rhodium.
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Interaction of 2D particles and phospholipid monolayersThe goal of this project is to understand how 2D particles at fluid-fluid interfaces interact with phospholipid monolayers found in biology, such as the lung surfactant DPPC. In the project, the main objective was to fabricate mono layer graphene to a certain size and shape to study their interactions with microscopy.
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Nanostructured titanium for medical devicesThe bulk and surface properties of pure titanium can be enhanced by nanostructuring to create a new generation of metals for medical implants. The healing response of bone to nanostructured titanium implants can be accelerated 20-fold by altering the metal's crystal size and grain boundary density. In addition, the strength of nanostructured titanium compared to conventional titanium can be increased between 30% to 100%. To incorporate these benefits into medical implants such as spinal rod or dental implants, nanostructuring must be applied to long rods or bars of titanium. One method of nanostructuring titanium is to subject long rods to high shear deformation. However, while this deformation creates nanoscale grains, it also imparts some residual stresses, which must be removed by annealing. In my research, we evaluated the annealing response of nanostructured titanium. Bars of pure titanium nanostructured by High Shear Deformation (HSD) were subjected to 1 hour annealing treatments between 200°C and 375°C. We evaluated the annealing response by measuring the microhardness. We confirmed the unusual phenomenon of "annealing hardening" that is unique to nanostructured metals. Generally, annealing reduces the hardness and strength of pure metals. But in the case of nanostructured titanium annealing can increase the strength. We were able to determine an optimum annealing temperature of 275°C.
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Mathematical mechanics of one-dimensional filaments in three-dimensional spaceA one-dimensional filament is a useful mathematical object for modeling a variety of physical phenomena such as vortex filaments. Through a description of the filament using the tangent, normal, and binormal vectors, we get a more meaningful description of the curve in terms of curvature and torsion. Hasimoto's transformation defines a mapping between a kinematic evolution of a space curve and nonlinear scalar equations evolving its intrinsic curve geometry. Through this transformation, the problem of understanding the time evolution of curves can be greatly simplified, yielding useful equations which arise in other areas of nonlinear physics. In our work, we generalize this transformation on arbitrary flows and test against several existing kinematic flows. We consider the time dynamics of length and bending energy to see that binormal flows are generally length-preserving, and bending energy is fragile and unlikely to be conserved in the general case. By describing a space curve in terms of curve geometry, we can perform a transformation that yields a useful description of the time evolution of the curve. Through a generalization of this transformation, we can better understand how the kinematic equation dictates the behavior of the curve, and how this relates to the modeling of physical phenomena.
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HCOOH decomposition on Pd catalysts for potential use as a liquid H2 carrierFormic acid (HCOOH) has emerged as a promising liquid H2 energy carrier due to its reasonable gravimetric and volumetric H2 densities, low toxicity, low flammability, and ease of handling. HCOOH could enhance the use of H2 fuel due to its ability to stay in a liquid state at a wide range of temperatures and its ease of transportation. Pd-based catalysts have shown to be a selective, stable, and reactive catalyst for HCOOH dehydrogenation due to its high reactivity at near ambient temperatures. This research utilizes in-situ infrared spectroscopy and steady-state kinetic experiments to better understand why Pd-based catalysts are effective by determining what intermediates occur and the overall reaction pathway. A 1 wt% Pd/SiO2 catalyst was prepared using strong electrostatic adsorption. Particle size was adjusted using and oxidative treatment followed by a reductive treatment to try and achieve estimated particle sizes. Mass spectrometry was utilized to understand the effects of particle size on the reaction rates and the overall catalytic performance. Through kinetic analysis, the reaction pathways were narrowed down and supported by using infrared spectroscopy (IR). IR showed no evidence of monodentate formates (HCOOM*), bidentate formates (HCOOB*) or carboxylate (COOH*) intermediates resulting in an intermediate similar in structure to molecular HCOOH. Overall, it was observed that the Pd/SiO2 catalyst was highly selective towards H2 and CO2 products. Future work will include synthesizing varying particle sizes to address the hypothesis that reaction rate increases with decreasing particle size and characterizing the catalyst.
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Global plastic material flow characterizing plastic packaging and plastics lost to the environmentPlastic is one of the most commonly used materials around the world, and its impact on our planet's ecosystems is undeniable. Initiatives to reduce plastic waste have gained much traction over the last five years, but the focus areas of such initiatives don't always align with notable positive impacts. This study aims to recognize the lifetime flow of plastics, from production to end of life, ultimately identifying where plastic reduction efforts can be most impactful. On a global scale, specific data on plastic production and material flow is generally lacking, so calculations relied heavily on data provided in the United Nations' 2015 report about mapping global plastics. By completing a material flow analysis using collected data, a Sankey Diagram was generated with a focus on "Packaging" and "Lost to Environment". This study showed that about 30% of plastic produced goes to packaging, and around 2% of plastic is lost to the environment in its end of life. While the overall percentage of plastic bound for environmental loss is small, it still amounts to over 8 million metric tons of plastic waste. Plastic lost to the environment stems from various sources, making it a difficult issue to tackle, but the importance of addressing this loss is critical. Reducing demand for plastic production through decreased plastic use is one of the most impactful methods to minimize plastic waste, and this study provides knowledge about which plastics pose the greatest threat, thus guiding where efforts should be focused.
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Interfacial characterization of oil-water systemsIn the process of producing and transporting crude oil, the occurrence of flow assurance dispersions/solids (water-in-crude oil emulsions, gas hydrates, asphaltenes) can reduce and even arrest the flow of hydrocarbons. By characterizing the interface of the oil and water, the behavior of multi-phase dispersions can be analyzed. This analysis can be used to find the stability of different dispersions. This research work focused on using several oils and brines, in order to characterize oil-water interfaces at conditions similar to field conditions. By creating emulsions with the oils and brines, emulsion stability could be determined by measuring the amount of separated water and the average droplet size. Larger droplet sizes indicated less stable emulsions. The water - oil interfacial tension is used to estimate the interfacial activity of natural surfactants. In general, a lower interfacial tension indicated the presence of more interfacially active natural surfactants, and thus a higher tendency to produce stable water - in - crude oil emulsions . This high interfacial activity has strong implications towards a low gas hydrate plugging risk of oil in the field. Using this information, the strategies to reduce gas hydrate plugging problems in the oil and gas industries can be optimized to reduce the amount of chemicals used, lowering the environmental impact.
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Evaluating surface reconstruction meshes without ground truthingCreating surface reconstructions from point clouds is common in computer graphics, vision, and video games. The most common way to evaluate the quality of surface reconstruction is to compare it to a ground truth mesh. However, this is not always possible. A novel method for evaluating surface reconstructions without ground truthing using simple computational geometry will be examined.
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Characterization of low-cost methane sensors for outdoor useMethane is known as a major greenhouse gas and there are not many economical ways of measuring smaller methane concentrations. Currently, small concentration methane sensing technology is expensive and difficult to apply on a large scale. A lack of inexpensive methane-sensing technologies leaves many small leaks in various machines undetectable. BPX Energy (Denver, CO) partnered with the Colorado Fuel Cell Center at Colorado School of Mines to characterize inexpensive, linearly applicable methane sensors for greenhouse gas detection. In this effort, the team at the Colorado Fuel Cell Center has created a testing apparatus featuring an environmental chamber to quantify sensor response over a range of known methane concentrations, operating temperatures, and humidities. Gas composition is regulated using mass flow controllers. Chamber temperature and humidity are measured by an Arduino interfacing with additional data acquisition hardware. Sensor response is measured using National Instrument's PCI analog-to-digital tools. The control and data collection are fully controlled by a LabView script designed to execute scripted tests. The research includes extensive data collection, curve fitting and analysis. In addition to characterizing sensor response to changes in humidity and temperature, the large set of sensors examined provides insight to the consistency of sensor outputs, and precision between sensors.
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Pairwise entanglement networks as a probe into non-equilibirum quantum dynamicsFollowing a sudden change of system parameters known as a quantum quench, the state of a quantum system can exhibit out-of-equilibrium dynamics. When the quench is across a critical point, a dynamical phase transition can occur, indicated by non-analytic behavior in a quantity known as Loschmidt echo. However, measuring the Loschmidt echo requires measurement of the entire quantum state, which is experimentally challenging, even for a moderate system size of a few tens of quantum particles. To address the challenge of detecting dynamical phase transitions, we investigate the possibility of using only information from two-body reduced states of a quantum many-body system for identifying dynamical phase transitions. These two-body reduced states allow us to calculate a network of different pairwise entanglement measures, including connected correlations, concurrence, and mutual information. As the measurement of all two-body reduced states only requires resources quadratic in system size, obtaining pairwise networks of these entanglement measures is experimentally practical. Upon attaining the pairwise networks, we directly examine the weighted adjacency matrices using network science and spectral graph analysis. Our results show that concurrence, an entanglement monotone, oscillates in phase with the rate function. As an example of our procedure, we consider a long-range transverse field Ising model with power-law interactions in the coupling strength. We further show that our methods may provide a considerably more efficient method for probing dynamical phase transitions in a large quantum many-body system. This work also paves the way for characterizing the role of pairwise entanglement in identifying critical phenomena.
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Systematic review of rigorous research in teaching introductory circuitsSystematic review is a meta-analytical framework for quantitatively searching, sorting, and synthesizing scholarly research on a particular topic. Systematic review techniques have recently gained traction in the field of engineering education. A systematic review performed over a specific area of practice can consolidate results from many studies into a synthesis of best practices. This paper presents the best practices for teaching introductory circuits which were identified through a systematic review of prior research. Relevant publications were identified and appraised with a set of coding criteria generated by the researchers. The coding results were examined and used to write a mixed-methods synthesis of consensus, disagreement, quality, and limitations amongst studies identified by the systematic literature review. The results of the review may inform educational techniques employed in post-secondary introductory circuits courses.
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Modelling thin-film transistors for understanding material properties and improving electronic device performanceAs new materials continue to develop through theoretical and experimental findings, it is desirable to have a reliable method of testing the materials to better understand their unique properties. Reliable computer modelling of electronic devices composed of these materials provides an inexpensive means of determining how a material will perform. Here we demonstrate the use of a computer software to accurately model electronic devices. We focus on amorphous silicon thin-film transistors and relate what is observed computationally to published experimental and theoretical results. We show that the computer models can be used to accurately study materials for applications in advanced electronic devices. We then discuss opportunities in new materials discovery that this type of modelling might permit.
