Engineering Commons^™

Localized Blood Occlusion Generation In An In-Vitro Circulatory Catheter System, Ryan D. Harris, Qi Yang, Hyowon Lee

The Summer Undergraduate Research Fellowship (SURF) Symposium

Hydrocephalus is a debilitating neurological disorder that involves the accumulation of cerebrospinal fluid in a ventricle of the brain. The implantation of a catheter commonly treats hydrocephalus with drainage. These catheters have a short lifespan due to obstruction from biological materials. Shunt systems have an extremely high failure rate of more than 40% failed within 1 year and up to 85% failed within 10 years. Previously, polymer-based flexible implantable magnetic micro-actuators were developed to clean up the catheter by mechanical vibration. We have demonstrated clearing of bacteria attachment and are proceeding to examine clearing effects on larger clotting materials, such …

Identifying The Pathways And Experiences Of Asian Students' Engineering Major Choice, Christine Chern, Xinrui Xu, Joyce Main

The Summer Undergraduate Research Fellowship (SURF) Symposium

Asian students’ pathways and experiences in engineering are not well-studied. Understanding pathways and experiences can inform students, parents, educators, and policymakers how to better approach the engineering major choice process. This study identifies pathways and experiences of Asian students choosing to major in engineering. Eleven semi-structured interviews of Asian students at a major research institution were analyzed in NVivo using thematic analysis. In this study, 8 Asian students chose engineering as a field of study and subsequently chose an engineering major while 3 chose an engineering major directly. Students following either pathway shared catalyzing interests, such as math and science, …

Atomistic Simulations Of Novel Nanoscale Semiconductor Devices: Resistance Switches And Two-Dimensional Transistors, Joseph P. Anderson, Mahbubul Islam, David Guzman, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

As transistors get smaller, we are achieving record levels of memory density. However, there is a limit to how small transistors can be made before their functionality breaks down. Thus alternatives to traditional transistor technology are needed. The two such technologies we examined are: resistance switching devices, which reversibly grow metal filaments through a dielectric, and two-dimensional transistors, which are capable of breaking through the scalability limit of traditional transistors. In order to design resistance switching devices which create filaments with some level of consistency, the dynamics of the filament formation need to be explored. Herein we model this process …

Modal Phonon Transport Across Interfaces By Non-Equilibrium Molecular Dynamics Simulation, Yang Zhong, Tianli Feng, Xiulin Ruan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Phonons represent the quantization of lattice vibration, responsible for heat transfer in semiconductors and dielectrics. Phonon heat conduction across interfaces is crucially important for the thermal management of real-life devices such as smartphones, electric vehicles, and satellites. Although recent studies have broadly investigated spectral phonon contribution to lattice thermal conductivity, the mechanism of phonon modal transport across interfaces is still not well-understood. Previous models, including the acoustic mismatch model (AMM) and diffuse mismatch model (DMM), only consider elastic process while neglecting inelastic phonon contributions. Herein, we employ spectral Non-Equilibrium Molecular Dynamics Simulation (NEMD) to probe the temperature and heat flux …

Single Cell Epigenetics, Li F. Lin, Chongli Yuan, Oscar F. Sanchez-Medina

The Summer Undergraduate Research Fellowship (SURF) Symposium

Epigenetics refers to the chromatin modifications that can change the expression of phenotypes but does not alter the underlining DNA. These modifications include but are not limited to histone methylation, histone acetylation, and chromatin folding. Studies suggested that methylation can activate or silence the expression of genes; and that histone acetylation can alter the chromatin structure. The changes in chromatin structure can expose hidden transcriptional factor binding sides and thus affect the differentiation potential. Moreover, these histone modifications are affected by the introduction of different metabolites and cellular microenvironment. To achieve a better understanding of how metabolites and environmental chemical …

Study Of Persistent Slip Bands Formed By Low Cycle Fatigue On Nickel-Based Superalloys At Room Temperature, Anjola Uprety, Sae Matsunaga, Michael S. Titus Dr., Michael D. Sangid Dr., Alberto W. Mello Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

The ability of Ni-based superalloys to withstand temperatures in excess of 1100⁰C makes them useful for applications in the hottest components in jet engines, gas turbines, and thrust engines. Increasing the efficiency of these gas turbine engines helps to reduce the fossil fuel consumption and the production of greenhouse gasses. A common mode of failure in these Ni-based superalloys is low cycle fatigue, in which narrow regions of high dislocation density, which are known as persistent slip bands (PSBs), can develop and lead to crack initiation. A detailed understanding of the formation and structure of PSBs has eluded …

A Spatial Stochastic Model Of Ampar Trafficking And Subunit Dynamics, Tyler Vandyk, Matthew C. Pharris, Tamara L. Kinzer-Ursem

The Summer Undergraduate Research Fellowship (SURF) Symposium

In excitatory neurons, the ability of a synaptic connection to strengthen or weaken is known as synaptic plasticity and is thought to be the cellular basis for learning and memory. Understanding the mechanism of synaptic plasticity is an important step towards understanding and developing treatment methods for learning and memory disorders. A key molecular process in synaptic plasticity for mammalian glutamatergic neurons is the exocytosis (delivery to the synapse) of AMPA-type glutamate receptors (AMPARs). While the protein signaling pathways responsible for exocytosis have long been investigated with experimental methods, it remains unreasonable to study the system in its full complexity …

The Effects Of Compaction On Reconstitution Characteristics Of Dairy Powder, Michelle P. Dixon, Rose Prabin Kingsly Ambrose, Dhananjay Ashok Pai

The Summer Undergraduate Research Fellowship (SURF) Symposium

Milk powders are becoming more ubiquitous within the food industry, and they offer consumers a convenient form for direct intake of dairy. The costs associated with dairy are reduced when products are converted to powder, which markedly increases shelf life at ambient temperatures. Creating compacts from powders further improves cost efficiency by reducing volume. However, milk powders typically possess poor rehydration properties, such as a slow dispersion rate and low solubility, and powder compaction additionally prolongs rehydration time, reducing consumer acceptability. Previous studies have shown that modifying dairy products before or during the drying process can improve rehydration properties, but …

Design A Continuously Tunable Microwave Filter With A Generalized Constant And Frequency Mapping Technique, Josh Shao, Runqi Zhang, Dimitrios Peroulis

The Summer Undergraduate Research Fellowship (SURF) Symposium

As the demand for agile and accurate communication increases, the fundamental of communication must be improved to support the needs. Current communication operates on an agreement, that each network company pays government to get licensed a range of frequency on the spectrum, and no others are legally allowed to use. This allows a limited number of users to operates at the same time. As the number of users increase, the spectrum become congested and user experience problem like dropping call. This problem can be solved, if users can be shifted between different licensed frequencies, depending on the capacity of the …

Dynamic Characterization Of Periodic Lattice Of Elastically-Connected Bi-Stable Elements Under Seismic Excitation, Lingwei Meng, Myungwon Hwang, Andres F. Arrieta Ph.D.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Metamaterials are engineered materials, typically in periodic arrangements, which exhibit unconventional or extreme properties not found in nature. Understanding the dynamics of metamaterials enables the design of structures with specific functionalities. The dynamics of metamaterials in linear regime has been relatively well studied in recent years, however the unique phenomena arising from nonlinearities in metamaterials are yet to be explored. In this paper, we focus on an array of bi-stable elements connected by elastic springs under various forms of external excitations acting on the entire system. The general equations of motion are derived to handle any degree-of-freedom (DoF) systems of …

The Response Of Schwann Cells To Weak Dc Electric Fields, Alexander T. Lai, Jianming Li

The Summer Undergraduate Research Fellowship (SURF) Symposium

Schwann cells are glial cells that serve the vital role of supporting neurons in the peripheral nervous system. While their primary function is to provide insulation (myelin) for axons, they also help regenerate injured axons by digesting severed axons and providing scaffolding to guide the regeneration process. This specific role of Schwann cells makes them highly important cellular targets following nerve injury. Although some efforts have been made to encourage Schwann cell migration after nerve damage, the use of electric fields to control cell responses remain unexplored; therefore, this experiment serves to characterize the behavior of Schwann cells to weak …

Pilot Performance With Advance Sensor Technlogies Considerations, Erin R. Groll, Nsikak Udo-Imeh, Steven Landry Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Research on human performance indicates people may discretely shift modes as the difficulty in tasks changes. These modes are referred to as “cognitive control modes.” Cognitive control modes are ways people operate and handle their process of thinking during a series of tasks. However, past work has been confined to subjective reports of these mode changes - objective markers in data of cognitive control modes, which should appear if these mode changes are truly discrete, have not be identified. This work will attempt to identify markers of cognitive control modes in data collected on pilots flying instrument approaches. Specifically, a …

Stability Analysis Of A Flexible Vehicle Model Controlled By Human Pilot Models, Abhishek Ajmani, Anil Bajaj

The Summer Undergraduate Research Fellowship (SURF) Symposium

There is a constant race among automobile manufactures to design safer vehicles while minimizing weight to reduce power consumption. Additionally, organizations like NASA and SpaceX are persistently working toward creating reliable, lightweight rovers to be used on the surface of Mars. However, the lightweight requirement often increases vehicle flexibility, which further develops a tendency toward instability in the lateral (sideways) direction. This investigation develops a mathematical model that represents the dynamics of a flexible vehicle in forward motion, and a heuristic human pilot model is proposed which controls the vehicle. Following such formulation, the combined vehicle and pilot model is …

Secondary Atomization: Drop Breakup In A Continuous Air Jet, Grant S. Sondgeroth, Longchao Yao, Catriona M.L. White, Daniel R. Guildenbecher, Jun Chen, Paul E. Sojka

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding drop breakup will optimize aircraft engine performance, reduce agro-chemical overspray, and improve pharmaceutical tablet efficacy. Large fuel fragments in engines lead to lowered fuel economy and higher pollutant emissions, while small drops yield more agro-spray drift into surrounding residential and environmental zones. Better pharmaceutical tablets will improve drug uptake and patient comfort.

Engineers and scientists are currently unable to predict the number, size, and velocity of fragments formed during important drop breakup processes. Therefore, we are required to measure these quantities. We use digital inline holography (DIH) to record three-dimensional diameter and position data for fragments formed during multi-mode …

Characterization Of Novel Photoresists For Sted-Enhanced Nanolithography, Brandon R. Franz, Paul Somers, Xianfan Xu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Stimulated emission depletion (STED) applied to nanolithography has greatly improved achievable resolutions and quality of nanoscale structures. The special resin used, called a photoresist, is currently the major limiting factor in further improvement in resolution and structure quality. Characterizing new formulations of photoresists and comparing their performance in STED-enhanced nanolithography to the performance of current formulations will allow for greater resolution and structure quality. With each photoresist, line structures are produced with a two-laser system including a writing, or excitation, laser and a depletion, or STED, laser. The line structures are exposed to the STED laser for a short duration …

Comparison Of Pm-Hip To Cast Alloy 625 For Nuclear Applications, Alexander L. Bullens, Keyou Mao, Janelle P. Wharry, Esteban Bautista

The Summer Undergraduate Research Fellowship (SURF) Symposium

PM-HIP, or Powder Metallurgy and Hot Isostatic Pressing, metals have been a low cost alternative to forged and cast structural metals within various industries. The nuclear industry has recently developed interest in PM-HIP alloys, but further research needs to be done to quantify their mechanical properties and characterize the microstructure. Specifically, we must understand the mechanical and microstructural evolution of PM-HIP materials after long-term operation at the elevated temperatures that PM-HIP components will experience in service. We focus on Ni-base alloy Inconel 625, and compare the PM-HIP version to the cast version. Our methodology consists of annealing samples to various …

Comparative Analysis Of Nanoscale Ultrasound Contrast Agents, Elly Y. Lambert, Luis Solorio

The Summer Undergraduate Research Fellowship (SURF) Symposium

Current ultrasound contrast agents utilize microbubbles as a blood pooling agent, but the size inhibits access to small capillaries. The development of nanoscale ultrasound contrast agents can enter small capillaries of tissues and aid in the detection of diseased states. However, current nano-formulations are flushed from the body over a short period of time. We developed a nanoscale ultrasound contrast agent with increased circulation time to allow for better detection of diseased states in the microvasculature of the body. Characterization (zeta potential, size, echogenicity and stability) and pharmacokinetic analysis were conducted on three nanoscale formulations: 1) Liquid based Bovine Serum …

Comparative Analysis Of Impact Attenuation Properties From Soccer Headgear, Kevin G. Mciver, Goutham N. Sankaran, Justin J. Markel, Tom M. Talavage, Larry J. Leverenz, Eric A. Nauman

The Summer Undergraduate Research Fellowship (SURF) Symposium

Athletes suffering from long-term neurocognitive deficiency due to subconcussive impacts is a major concern for football and soccer players today. Football players wear helmets that can help reduce injury risks like skull fractures, and these helmets must meet standard criteria that determinines how well a functional helmet should reduce accelerations of the player’s head. Currently no standard exists for testing soccer headgear despite studies demonstrating soccer players experience similar magnitudes of impacts. In this study, a modal impact hammer was used in conjunction with a Hybrid III 50th percentile test dummy head to simulate impacts experienced by soccer players to …

Burning Surface Temperature Measurements Of Propellants And Explosives Using Phosphor Thermography, Ethan A. Whitaker, Alex D. Casey, Steven F. Son

The Summer Undergraduate Research Fellowship (SURF) Symposium

Temperature measurements of propellants and explosives are necessary to create accurate models which lead to better understanding of energetic characteristics such as burning rate. Previous attempts at measuring surface temperatures of burning propellants and explosives using thermocouples have suffered from large uncertainty. Thermographic phosphor thermography employs ceramic powders called phosphors whose spectroscopic properties can be used to remotely and nearly non-intrusively measure temperature. Improved methods were developed for application of this technique to energetic materials to yield more accurate, two-dimensional temperature measurements. In this study, zinc oxide doped with gallium, a thermographic phosphor, was mixed into HMX and RDX powder, …

Two-Color Polarization Spectroscopy Measurement Of Nitric Oxide, Ziqiao Chang, Aman Satija, Robert P. Lucht

The Summer Undergraduate Research Fellowship (SURF) Symposium

Nitric Oxide (NO) is a greenhouse gas that contributes to smog and acid rain. Commercial combustion engines and turbines are significant sources of NO emission. Two-color Polarization Spectroscopy (PS) will be used to measure the collision-induced resonances of NO in gas mixtures. The effect of collision partners, such as He and Ar, on the line-shape of NO molecule will be studied. This experiment requires the use of two dye laser systems to generate 226nm beam from frequency mixing of 355nm and 622nm. This enhanced the scan range and improved the ease of operation. One dye laser will be used to …

Improving Methods Of Doping On Black Phosphorus, Yuqin Duan, Adam Charnas, Jingkai Qin, Peide Ye

The Summer Undergraduate Research Fellowship (SURF) Symposium

Black phosphorus (BP) is a 2D semiconducting material with high carrier mobility. It is usually p-type due to oxidation states near its valence band. Although achieved through other growth methods, n-type doping has not yet been accomplished through the modern chemical vapor transport (CVT) growth method. To address this issue, small amounts of tellurium were added to Red Phosphorus to act as a dopant during the CVT growth process in addition to tin(Sn) and tin(IV) iodide, which facilitate growth. The chemicals are heated up to 600°C and precisely cooled in a 21-hour process, during which BP crystals should form. After …

How To Enhance Interdisciplinary Competence—Interdisciplinary Problem-Based Learning Versus Interdisciplinary Project-Based Learning, Mirjam Brassler, Jan Dettmers

Interdisciplinary Journal of Problem-Based Learning

Interdisciplinary competence is important in academia for both employability and sustainable development. However, to date, there are no specific interdisciplinary education models and, naturally, no empirical studies to assess them. Since problem-based learning (PBL) and project-based learning (PjBL) are learning approaches that emphasize students’ collaboration, both pedagogies seem suitable to enhance students’ interdisciplinary competence. Based on the principle of constructive alignment and four instructional principles on interdisciplinary learning, this paper proposes that students profit more from interdisciplinary PBL (iPBL) than interdisciplinary PjBL (iPjBL). A pre-post study was conducted with a sample of 95 students participating in iPBL and 183 students …

Biomechanics Of Snoring And Sleep Apnea, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

To understand the mechanisms of snoring and sleep apnea a first-principles biomechanical analysis was done for airflow through branched parallel channels, separated by a freely movable soft palate, and converging to a common channel at the base of the tongue in a “Y-shaped” configuration. Branches of the Y describe slit-like passages on the nasal and oral sides of the soft palate, when the palate is pushed by backward movement of the tongue to form a wedge between the tongue surface and the posterior pharyngeal wall. The common channel of the Y describes the oropharyngeal passage between the base of the …

An Operationalized Model For Defining Computational Thinking, Tony A. Lowe, Sean B. Brophy

School of Engineering Education Graduate Student Series

The Computational Thinking (CT) conceptual framework is entering its second decade of research yet still lacks a cohesive definition by which the field can coalesce. The lack of clear definition makes assessment tool challenging to formulate, pedagogical efforts difficult to compare, and research difficult to synthesize. This paper looks to operationalize differing definitions of CT enhancing the ability to teach then assess the presence of CT. Expanding upon CT definitions, industry practices and processes, and educational theory, we link existing concepts and propose a new element to model an active definition of CT as a theoretical framework to guide future …

Mathematical Description And Mechanistic Reasoning: A Pathway Toward Stem Integration, Paul J. Weinberg

Journal of Pre-College Engineering Education Research (J-PEER)

Because reasoning about mechanism is critical to disciplined inquiry in science, technology, engineering, and mathematics (STEM) domains, this study focuses on ways to support the development of this form of reasoning. This study attends to how mechanistic reasoning is constituted through mathematical description. This study draws upon Smith’s (2007) characterization of mathematical description of scientific phenomena as ‘‘bootstrapping,’’ where negotiating the relationship between target phenomena and represented relations is fundamental to learning. In addition, the development of mathematical representation presents a viable pathway towards STEM integration. In this study, participants responded to an assessment of mechanistic reasoning while cognitive interviews …

Understanding The Impact Of Strategic Team Formation In Early Programming Education, Tony A. Lowe, Sean B. Brophy

School of Engineering Education Graduate Student Series

This evidence based research looks at the impact of a team-based instruction on learning to program in a first year engineering course designed under the Bauhaus studio model. Each team is formulated with a “more knowledgeable other” [1], or for this paper the “ringer” based on selfreported prior learning. The ringer is intended to support the team through early programming challenges. In addition to the professor and teaching assistants, having a peer mentor can yield higher satisfaction and confidence in learners [2]. Our analysis evaluates learning outcomes as student progress through the term, comparing performance based on the performance and …

Teachers’ Incorporation Of Argumentation To Support Engineering Learning In Stem Integration Curricula, Corey A. Mathis, Emilie A. Siverling, Aran W. Glancy, Tamara J. Moore

Journal of Pre-College Engineering Education Research (J-PEER)

One of the fundamental practices identified in Next Generation Science Standards (NGSS) is argumentation, which has been researched in P-12 science education for the previous two decades but has yet to be studied within the context of P-12 engineering education. This research explores how elementary and middle school science teachers incorporated argumentation into engineering design-based STEM (science, technology, engineering, and mathematics) integration curricular units they developed during a professional development program. To gain a better understanding of how teachers included argumentation in their curricula, a multiple case study approach was conducted using four STEM integration units. While evidence of argumentation …

Students’ Successes And Challenges Applying Data Analysis And Measurement Skills In A Fifth-Grade Integrated Stem Unit, Aran W. Glancy, Tamara J. Moore, Selcen Guzey, Karl A. Smith

Journal of Pre-College Engineering Education Research (J-PEER)

An understanding of statistics and skills in data analysis are becoming more and more essential, yet research consistently shows that students struggle with these concepts at all levels. This case study documents some of the struggles four groups of fifth-grade students encounter as they collect, organize, and interpret data and then ultimately attempt to draw conclusions or make decisions based on these data. The activities in which the students engaged were part of an integrated science, technology, engineering, and mathematics (STEM) unit that had students collecting and analyzing data both in the context of learning science concepts and in the …

Perspectives On Failure In The Classroom By Elementary Teachers New To Teaching Engineering, Pamela S. Lottero-Perdue, Elizabeth A. Parry

Journal of Pre-College Engineering Education Research (J-PEER)

This mixed methods study examines perspectives on failure in the classroom by elementary teachers new to teaching engineering. The study participants included 254 teachers in third, fourth, and fifth grade who responded to survey questions about failure, as well as a subset of 38 of those teachers who participated in interviews about failure. The study first examines the literature about failure in the contexts of engineering and education. Failure is positioned as largely normative and expected in engineering, whereas in education, learning and failure have a more tenuous relationship. Identity, failure avoidance, failure as part of the learning process, growth …

Undergraduate Engineers And Teachers: Can Students Be Both?, Malinda S. Zarske, Maia L. Vadeen, Janet Y. Tsai, Jacquelyn F. Sullivan, Denise W. Carlson

Journal of Pre-College Engineering Education Research (J-PEER)

Today’s college-aged students are graduating into a world that relies on multidisciplinary talents to succeed. Engineering college majors are more likely to find jobs after college that are outside of STEM (science, technology, engineering, and mathematics) fields, including jobs in healthcare, management, and social services. A survey of engineering undergraduate students at the University of Colorado Boulder in November 2012 indicated a desire by students to simultaneously pursue secondary teacher licensure alongside their engineering degrees: 25 percent ‘‘agreed’’ or ‘‘strongly agreed’’ that they ‘‘would be interested in earning grades 7–12 science or math teaching licenses while [they] earn [their] engineering …