Engineering

Bowden, Lucy; Monroe, Jacquelyn; Bowden, Anton E.; Jensen, Brian D. (Brigham Young University)
Faculty Advisor: Bowden, Anton (Engineering, Mechanical Engineering); Jensen, Brian (Engineering, Mechanical Engineering)

Previously our lab has shown that carbon-infiltrated carbon nanotube (CI-CNT) surfaces enhance osseointegration and resist biofilm formation, making them attractive possibilities as orthopedic implant materials. For these applications, CI-CNTs and their underlying substrate material must be able to withstand aqueous physiologic conditions. Due to microstructural changes that occur during CI-CNT production, we hypothesized that stainless steel substrate materials experience a loss of their protective, passivating layer, subsequently corroding when immersed in a simulated biological environment. The purpose of the study was to compare corrosion resistance of CI-CNT coated stainless steel substrates to bare stainless steel control samples after two days of incubation in different physiological analog media.

CI-CNTs were grown on 316L stainless steel samples which were sonicated for 20 minutes in isopropyl alcohol and given a 2 minute heat treatment in air at 800°C, followed by a 20 minute growth at the same temperature in ethylene and argon. Carbon infiltration was done for 5 minutes in the same gases at 900°C. The samples were autoclaved and placed into different media including deionized water, phosphor buffered saline solution (PBS), and DMEM culture media. The samples were then incubated for 48 hours at 37°C.

Macroscopic observation showed no obvious signs of corrosion (e.g., discoloration of the liquid media, cloudiness, physical changes in sample appearance) for any of the control samples, or for CI-CNT coated samples in deionized water. In contrast, the CI-CNT coated samples immersed in PBS and culture media exhibited significant discoloration and a cloudy appearance. Subsequent SEM images of the CI-CNT coated samples which had been immersed in culture media and PBS showed foreign residue. Energy dispersive x-ray analysis characterized this residue as having markedly higher levels of sodium and phosphorus than a baseline CI-CNT coated stainless steel sample. SEM images of the bare stainless steel samples and the CI-CNT samples cultured in deionized water showed no signs of corrosion or residue.

Our preliminary results illustrate that media containing salts initiated corrosion of CI-CNT coated stainless steel samples, likely due to disruption of the passivating layer in the substrate. Future work will explore methods for re-establishing the passivating layer in stainless steel materials.

Kjar, Andrew; Heap, Mitchell; Wadsworth, Ian; Vargis, Elizabeth; Britt, David (Utah State University)
Faculty Advisor: Britt, David (College of Engineering, Biological Engineering Department); Vargis, Elizabeth (College of Engineering, Biological Engineering Department)

Quercetin is a flavonoid that exhibits antiviral activity against cytomegalovirus infection, the leading cause of non-genetic sensorineural hearing loss in infants. However, delivering quercetin as an antiviral treatment is challenging as it is sparingly soluble in water and highly susceptible to oxidation once solubilized. This study investigated quercetin encapsulation in micelles formed from self-assembled nanocariiers of differing hydrophobic and hydrophilic chain lengths (specifically, F127, P123, and F68). Samples were investigated weekly for two months using UV-vis spectroscopy and dynamic light scattering to determine quercetin chemical stability and micelle size, respectively. Free quercetin and F68-encapsulated quercetin oxidized within one week in PBS, while quercetin encapsulated by Pluronics F127 and P123 remained stable and encapsulated over two months. Pluronics F127 and F68 have similar PEO chain lengths, but the lower hydrophobic PPO content of F68 was insufficient to allow quercetin-loaded F68 to form stable carriers. As a consequence, F68 also did not protect quercetin against oxidation. The decreased PEO chain length of P123 did not inhibit micelle formation nor oxidative protection. These data suggest the length of the hydrophilic chain is not a determining factor in the chemical stability of encapsulated quercetin. Instead, shielding effects appear to correlate to longer hydrophobic segment lengths, as in F127 and P123.

Conclusions: The ability of the selected Pluronics to encapsulate quercetin in stable micelles and inhibit oxidation was highly dependent on PEO/PPO ratios. This work indicates selection of the appropriate delivery vehicle is necessary to improve quercetin's efficacy as an antiviral and antioxidant for inhibiting CMV and associated SNHL.

Burrows, Tessa; Paterson, Chase; Harris, Tom; Jones, Justin; Elizabeth, Vargis (Utah State University)
Faculty Advisor: Vragis, Elizabeth (College of Engineering, Biological Engineering Department)

Age-related macular degeneration (AMD) is the leading cause of vision loss and blindness in developed nations. To better treat this disease, an accurate model of the retina is needed to study how its healthy and diseased functions. Modeling Bruch's membrane (BM) — a semipermeable layer separates the specialized cells in the retina from blood vessels and becomes more thick and brittle with age — can aid in identifying how the cells associated with AMD, retinal pigmented epithelial (RPE) cells, grow and respond to stress. This project identifies how the brittleness and thickness of a synthetic BM affects cell function and stress factor production in RPE cells. Previous research compared the growth of RPE cells on Transwell membranes and recombinant spider silk proteins (rSSPs) to model BM, and found rSSPs membranes to support RPE growth. Using rSSPs, nonporous membranes with thicknesses of approximately 36 and 50 µm were fabricated to simulate a thicker and more brittle, aged BM. Control assessments were performed with Transwell support membranes, and with 15 µm rSSPs membranes which have been found to support the growth of RPE cells. RPE cells (ARPE-19) were grown on the membranes to confluency and the permeability of the membrane-cell complex was assessed with a size dependent permeability assay with fluorescent dyes of varying molecular weight. Preliminary results found that 36 and 50 µm membranes have a lower permeability coefficient with 7 days of cell growth and a 10 kDa dye. This project is ongoing, and future work includes protein staining to determine the formation of tight junctions and the expression of vascular growth factors associated with AMD. Differences in permeability across the thicker cell-membrane complexes suggest RPE cells have a reduced ability to transport waste across BM. Using rSSPs provides a tunable substrate to quantify the importance of BM in AMD.

Gibbons, Andrew; Clingo, Kelly; Emmett, Darian; Fullwood, David; Bowden, Anton (Brigham Young University)
Faculty Advisor: Fullwood, David (Brigham Young University, Ira A. Fulton College of Engineering; Engineering and Technology); Bowden, Anton (Brigham Young University, Ira A. Fulton College of Engineering; Engineering and Technology)

Spine dysfunctions such as stenosis and herniated discs have traditionally been diagnosed using X-ray or MRI imaging techniques; but these methods capture a snapshot of the problem, without revealing the positional dependence of the causes and effects. In order to provide a richer dataset to physicians, an NIH-funded project has begun with the aim of tracking details of spinal motion for people with healthy and symptomatic backs. Novel nanocomposite strain gauges will be used to capture skin deformation during typical back motion, and correlate these data with back motions that are known to reveal chronic subcutaneous trauma. This paper focuses on the optimal placement of strain gauges for maximum resolution of the underlying biomechanics.

An array of reflective markers was placed on a healthy individual's lower back between the L5 and T10 vertebrae. A QUALISYS motion capture lab was then used to determine the coordinates of these markers during flexion, rotation, flexion with rotation, and side bending. These motions were repeated 3 times for 10 seconds. The distances between markers were calculated for each motion and the strain values between resting and flexed positions were determined. Initial validation was performed by comparing a maximum tensile strain of 0.54, between the L5 and L1 vertebrae in flexion, with a previously reported value of 0.5 in the literature.

This paper will report the development of an optimal arrangement of sensors for resolving the relevant biomechanics of the spine, based upon a detailed analysis of the optical marker results. Future work will utilize these results to develop a skin mounted, wearable sensor array that can measure the real-time kinematics of the spine and compare them with a database of healthy and low back pain subjects using a machine-learning paradigm. We hope to use the system to identify mechanical sources of low-back pain.

Jacobs, Matt (Brigham Young University)
Faculty Advisor: George, Andy (Engineering, School of Technology); Miles, Mike (Engineering, School of Technology)

Composites are unique materials in many respects. When fabric woven from carbon fibers is joined with a thermoset resin in a controlled environment, it results in a very strong material. One aspect of this construction that provides great strength lies in the crosslinked chains of plastic polymers, which form strong bonds as the resin cures. It's a two-edged sword, though. Although the resin and the composite are quite strong together, they are very difficult to pull apart once they're formed, in order to be able to use again in the future. As such, composite structures formed with industry-standard thermoset resins have a single-use lifespan. The cheapest thing to do to dispose of them is to simply throw them away. However, by isolating the dry fibers by burning off the resin (a process called pyrolysis), the fibers are able to be processed again in useful ways — they are reclaimed. My research focuses on pyrolysis and ways to optimize its process. I aim to showcase its environmentally-friendly capabilities through making new composite structures with fibers reclaimed via pyrolysis to lessen landfill waste.

For the experimental phase of the research, a roll of unprocessed carbon fiber material will be selected for producing 4 test groups:
Virgin-sized carbon fibers
Fibers that have undergone pyrolysis
Fibers infused to part and reclaimed with pyrolysis, oxygen-free environment
Fibers infused to part and reclaimed with pyrolysis, ambient air environment

Fiber samples will then be processes into 3mm length fibers. Fibers will then be introduced to Matrix at TBD% Fiber volume content, following which, dog bones will be molded from samples for tensile testing. Dog bones will then be tensile tested and analyzed at fracture point.

Response variables involved include:
Oxygen vs deoxygenated atmosphere (during pyrolysis),
Bath vs spray vs no application (method of sizing).
Control variables include:
Fiber & Sizing,
Fiber resin ratio,
Fiber Length,
Pyrolysis Time & Temp.

Post-pyrolysis fibers will then be chopped, blended with plastic (polymer TBD) and extruded, cut into pellets, and injection molded into dog-bones for tensile testing. The resulting mechanical properties of the carbon fiber reinforced plastic compared with standard injection molding polymers as well as fully-cured composite.

Although uncertainties exist in the viability of sizing application and surface treatment for composites recycling, building upon previous work in pyrolysis and utilizing the unique resources available at BYU (composites lab, ready access to aerospace-grade fibers, industry standard processing equipment, scanning electron microscopes, etc.), the work's importance and potential for contributions to the field are clear.

(Pace, Jenessa; Ence, Elodie; Kunz, Allison; Stevens, Rebecca; Kunz, Amber; Cooper, Izaak; Nelson, Alicia; Asplund, Alyssa; Stock, Julianna) (Brigham Young University)
Faculty Advisor: Williams, Gustavious (Ira A. Fulton College of Engineering and Technology, Civil and Environmental Engineering)

Photogrammetry using Unmanned Aerial Vehicles (UAV) has become more relevant to water resources issues. The models generated can be highly accurate and detailed. The use of ground truth is an integral part of ensuring the accuracy of such models. Ground truth based on GPS-obtained data of visual targets gathered in the field prior to UAV data collection are used to improve post processing accuracy. Proper spacing of ground truth is primarily dependent on the flight path of the UAV during data collection, flight height, and image resolution.
One developing task is creating models of full-pool bathymetric maps for reservoirs - using UAVs for above the waterline and sonar for below. Due to their erratic shapes, capturing the shorelines of reservoirs requires erratic flight paths. Planning ground truth spacing requires special care.
To determine proper ground truth spacing we completed a field survey at Starvation Reservoir, near Duchesne, Utah. We selected a two mile stretch along the north side of the reservoir to test various ground truth spacings. We flew the test stretch with two flights, one taking nadir photos and one with the photos taken at an angle of about 30 degrees, more normal to the shoreline. The primary placement of ground truth points was approximately 0.25 miles apart. After the data was recorded, we created models using Metashape software using different ground truth spacing, using spacings of 0.25, 0.5 and 1 mile. We used Cloud Compare software to determine the error between each model. We assumed that the model generated using 0.25 points/mile was "truth". We used this preliminary information to determine that for bathymetry maps, a ground truth spacing of 1 mile/point was acceptable, we are continuing our research to refine this finding.

Mark Langeveld (University of Utah)
Faculty Advisor: Langeveld, Mark (University of Utah, Engineering)

Introduction:

The risk of getting type 2 diabetes has been widely found to be associated with lower socioeconomic position across countries. Not only the financial burden but also the clinicians often having the long waitlists for one-on-one assessment of chronic disease patient's behavior makes it difficult for timely treatment and monitoring supplies. Among the top 10 diseases that are causes of death, Diabetes is the most self-manageable chronic disease. Type 2 diabetes patients often require insulin therapy as well as self-managing on eating well and exercising. A mobile app can be applied as a self-managing mechanism that treats chronic complications of diabetes. I will describe my work to analyze five commercially available mobile apps that are effective in improving diabetes-related outcomes.

Method:

I analyzed with technology reviews of iterative mobile app design of each mobile app(Glucose Buddy, Diabetes care4Life, Diabetes Diary, BlueStar Diabetes, Gather Health) and reviewing comments from peer and public review. I organized the findings by test process with diabetes patients through three categories for this report: 1. App features (on which platform that the app is available, what the app does, cost, etc.) 2. App usability and quality of tracking presented as an average of three scores given by the University of Utah healthcare researchers 3. Summary of the evidence from the evaluation of each category of patients who are motivated and who were not: monitoring glycemic control, glucose control, blood pressure, HbA1c improvement, weight, and diabetes treatment satisfaction

Result:

The record comprised 30 patients, of which 10 completed the mobile app module for 6 weeks. Demographics were similar for users and nonusers. Of the application users, the behavior improvement of pre-test and posttest scores were better for users compared with non-users (+1.8%). Of the users, 92% reported that the application had significant improvement (p < 0.05) in an outcome compared with HbA1c and glycemic control. The usability score of each app evaluated by healthcare researchers was (Glucose Buddy: 72.3 (out of 100), Diabetes care4Life: 45, Diabetes Diary: 16, BlueStar Diabetes: 85, Gather Health: 60) Without additional support from a health care provider, 5 mobile apps demonstrated an improvement in fasting blood glucose, 2-hour post-breakfast blood glucose, diabetes knowledge, and self-care behaviors compared with controls.

Conclusion:

I have analyzed and created a prototype of a mobile app that fills the gap between efficacy, cost, and features from the limited statistical evidence. Patients were satisfied with the use of the mobile health app for Diabetes, and the use of the program significantly improved their behavior and knowledge retention. Tailoring the traceable evaluation of mobile app to patient preferences and needs and updating the tools could empower and guide the patients to effective mobile apps in improving diabetes outcomes.

Parkinson, Bethany; Andrews, David; Magleby, Spencer (Brigham Young University)
Faculty Advisor: Magleby, Spencer (Brigham Young University, Mechanical Engineering)

Increasing worldwide urbanization is leading to a rising population of people living in apartments. Apartments typically have short leases, which lead to a high turnover rate, or number of renters that move in per year. For example, the 2018 turnover rate in New York City was 30.5%. People who move this often usually buy cheap furniture each time they change apartments, because carrying furniture on public transportation is impractical. The goal of our research is to create furniture that allows people who move often to avoid re-purchasing furniture. This goal leads to three design requirements. First, the furniture should be easily collapsed and deployed. This permits the furniture to be conveniently stored and transported. Ideally, the furniture could be deployed with one hand. Second, the furniture should be inexpensive, both in manufacturing processes and material selection. Lastly, the furniture should be aesthetically pleasing. We have utilized origami as a method to achieve these design objectives, because it can be deployed in one motion.

There are significant challenges to designing and implementing origami-inspired furniture. For example, any joints between the legs, seat, table, and back of the furniture need to allow not only for the furniture to be stable in its deployed state, but also to be flat in its non-deployed state. Additionally, the employed joints must account for the thickness of the material. Each type of joint that is adaptable to thick materials was therefore considered and analyzed in the specific loading situation of a chair. Using these criteria and three unique types of joints, a variety of chairs were conceptualized. After prototyping, each type of chair was expanded to create an entire family of furniture, including a table, stool, and couch. The principles and design approaches developed in this project have generated origami-inspired furniture that is easily transportable, functional, inexpensive, comfortable, and aesthetic.

Mehr, Judd; Alvarez, Eduardo; Cardoza, Adam; Ning, Andrew (Brigham Young University)
Faculty Advisor: Ning, Andrew (Brigham Young University, Mechanical Engineering)

Wind power is an attractive alternative energy source because it is sustainable, clean and cost effective. However, wind energy is difficult to harvest because wind is irregular, seasonal, and often far away from urban areas. Several organizations have sought to solve this problem by designing wind harvesting aircraft, called windcraft. Windcraft are aircraft that are tethered to the ground, propel themselves into the air, enter steady flight in a crosswind, and allow the propellers to spin freely. The wind keeps the windcraft aloft and forces the propellers to turn backwards, turning them into turbines. Power generated from the turbines is sent down the tether and stored. Windcraft provide several advantages beyond those of conventional wind turbines, including high portability due to its smaller weight.

This research employs aerodynamic analysis to determine the forces on the turbines and lifting surfaces of a windcraft modeled after the Makani M600, an 8-rotor prototype produced by Makani Technologies. The analysis is a combination of modeling methods with varying fidelity, including the vortex lattice, vortex particle, and blade element momentum methods. The vortex lattice method models the lifting surface as a sheet of vortices that have the same capability to push on the oncoming flow as the lifting surface would. The vortex particle method uses a set of discretized fluid motion equations in a form that allows for the solution of the strength of the vortex at each point in the flow. The blade element momentum method uses two theories, the blade element theory and the momentum theory, to calculate the power, thrust and axial air velocity of a propeller or turbine. The modeling methods are validated by using experimental data from The Mexico Project and NASA. We implement basic design space exploration to display this model's compatibility with design optimization.

Pulsipher, Kyle; Despain, Dillon; Wood, David; Fullwood, David T.; Bowden, Anton E. (Brigham Young University)
Faculty Advisor: Bowden, Anton (Brigham Young University - Ira A. Fulton College of Engineering, Mechanical Engineering); Fullwood, David (Brigham Young University - Ira A. Fulton College of Engineering, Mechanical Engineering)

Design and Testing of Flexible Wiring Systems in Biomechanical Devices
Kyle Pulsipher, Dillon Despain, David Wood, David T. Fullwood, Anton E. Bowden
A major challenge to wearable electronic devices is the implementation of required wiring and hardware that can accommodate large deformations and strain. For example, several current biomechanical engineering projects utilize a nanocomposite, wide-range, wearable strain sensing technology developed at BYU. Our research challenge was to create a wearable system of conductive links between a multi-sensor system and a microcontroller, while keeping the system low-profile, inexpensive, and functional when experiencing strains of at least 60%.

Several solutions were hypothesized and tested, including experimental silicone composite solutions with dispersed conductive nanofillers. Mechanical solutions were also contemplated, in the form of geometrically positioning a traditional wire in such a way that it could strain the required amount.

Our final solution utilizes a fine-gauge wire shaped into a sine curve, whose period and amplitude are controlled, such that the stretched length (the arc length of the sine curve) is a required strain factor longer than the period of the function. The wire is coated in an elastic silicone body that maintains the wire at the unstrained shape and length. Our implementation provides 130% of the wiring system and accommodates 16 independent sensor connections.

The wiring system is positioned in such a way that the wires are hidden in the artistic form of the sensing system. This electrical structure is both highly practical and aesthetically pleasing.