Gemstone Team Research
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Item INVESTIGATING METHODS OF BLOOD PRESSURE MEASUREMENT: COMPARING CORRELATIONS OF MULTIPLE PULSE TRANSIT TIMES TO BLOOD PRESSURE(2019) Anand, Aman; Ashai, Shereen; Bent, Michael; Foster, Jackson; Goldberg, Ryan; Murray, Eric; Sandoval, Jonathan; Stein, David; Weatherly, Sarah; Youngs, Nick; Hahn, Jin-OhCurrently, one in three American adults suffer from high blood pressure, a condition known as hypertension, yet only half have their condition under control (CDC, 2016). Methods of continuous blood pressure measurement have been examined by the team over the past few years. Using five hemodynamic interventions to fluctuate blood pressure, blood pressure data was gathered from 35 healthy adult participants. This data was useful in measuring pulse transit time and determining optimal locations for biosensor placement. Participants were also surveyed to collect public opinion on potential health monitoring devices for future development. Furthermore, the potential of using mobile device applications was examined as an alternative method of retrieving signals and calculating blood pressure. The results from this project indicate that for a mobile device application, the best signals to use for estimating blood pressure are PPG maximum to ECG R-wave, having an average correlation of - r = 0.73 for the systolic blood pressure and -r = 0.71 for the diastolic blood pressure.Item GENETIC MODIFICATION OF PROBIOTIC ESCHERICHIA COLI TO PRODUCE OMEGA-3 FATTY ACIDS(2019) Greenberg, Julianna; Kalla, Neha; Kambhampati, Roja; Murphy, Erin; Qadri, Aasheen; Reveiz, Mateo; Biswas, DebabrataOmega-3 (Ω-3) fatty acids are an essential component of the human diet that have been linked to reduced risk of both neurological and cardiovascular diseases in humans; however, Ω-3 fatty acids are far underconsumed in the typical American diet. The expense of fatty fish such as salmon makes obtaining Ω-3 fatty acids difficult for much of the population and plant alternatives have proven to be insufficient sources of this vital nutrient. To address aforementioned issues, probiotic bacteria will be modulated to produce Ω-3 for the potential application in fermented food products like yogurt. This new application would not only increase access to Ω-3, but also provide a significant environmental benefit through reduced overfishing and ocean contamination currently associated with the mass production of fish products for their Ω-3 benefits.Item DESIGN AND FABRICATION OF A PHOTONIC MEMRISTOR USING A METAMATERIAL(2019) Lay, Daniel; Liu, Thomas; Shulman, Phillip; Yahya, Humza; Ouyang, MinA memristor is a nonlinear circuit element whose impedance depends on the history of current through the device. Photonic circuits are circuits that use photons rather than electrons to transfer signals. Memristors, then, exist in photonic circuits. With this in mind, we proposed, designed, and constructed the analogue of a memristor for use in a photonic circuit, in the infrared regime. The design focuses on an array of silver pillars, of varying pitch. The team's simulations indicate that changes in the pitch of the array modify the transmittance of infrared-regime light rays. After conducting these simulations, the team constructed a five-by-fi ve array of polymer rods, with height 3.5 μm and pitch 5 μm, and coated in 100 nm of gold. We then immersed the array in various PNIPAm solutions. PNIPAm expands with increasing temperature around 32 °C, and so is thought to change the pitch of the array. This is the first use of a PNIPAm-based polymer to attempt to achieve a variable pitch, for use in a photonic memristor.Item MODELING POWER CONSUMPTION AND OPERATION IN A BISTABLE ELECTROWETTING-BASED DISPLAY(2019) Chatterjee, Trinish; Chowdhury, Nazifa; Ittner, Jason; Jiao, Alexander; Nguyen, David; Singh, Karam; Weatherford, Alexander; Abshire, PamelaTeam VOLTAGE is an undergraduate research team based in University of Maryland’s Gemstone research program. Their objective is to advance research related to modeling e-paper technologies. Experimentation with electrowetting display fabrication techniques, followed by modeling based on measured parameters is performed. Both numerical and circuit-based simulations are performed. Numerical simulations demonstrate correlations between pixel size, alpha constant, actuation voltage, and power consumption. Circuit-based simulations demonstrate a method for determining power consumption of an electrowetting-based display and give an accurate power consumption for a specified display.Item DEVELOPMENT OF AN ADDITIVELY MANUFACTURED RIGID SPACESUIT COMPONENT FOR LONG DURATION MISSIONS(2019) Bartlett, Harrison; Bowser, Joseph; Callejon Hierro, Carlos; Garner, Sarah; Guloy, Lawrence; Hnatov, Christina; Kalman, Jonathan; Sosis, Baram; Akin, DavidLong duration human exploration of Mars will pose demands on spacesuits that current designs are unable to overcome, including the need for in-situ replacement and repair of suit components. Advancements in additive manufacturing (AM) technologies provide capabilities to repair or replace rigid pressure garments on-site and on-need. This thesis focuses on a potential application for in-situ hard suit manufacturing: the integration of AM components into a functional spacesuit arm. Material tests were conducted and top candidates were selected for the joint segment components. AM bearing con figurations were tested under operational loads and seals were incorporated for pressure retention. Selected components were integrated into a hard suit arm, which was compared to the Shuttle-era EMU arm through human tests in a pressurized glove-box. The results indicate that further re finement of hard suits has the potential to match the performance of operational EMU models while reducing the logistical issues with current spacesuits.Item SUSTAINABLE GREYWATER FILTRATION ON A RESIDENTIAL SCALE(2019) Alving, Denise; Arnold, Ry; Hunsicker, John; Kebede, Yoseph; Sean, Naimi; Perry, John; Rudman, Shaina; Adomaitis, Raymond A.This project proposes a sustainable greywater filtration system for residential-scale water reuse. Recycled greywater can be used in toilet water, outdoor irrigation, car washing, and clothes washing, reducing the demand for potable water. Although pilot-scale systems have been demonstrated for greywater recycling, residential-scale applications remain unexplored, as treatment options on a residential scale are limited. This project designed and implemented a residential-scale greywater filtration system into reACT, the University of Maryland’s 2017 Solar Decathlon House. The system was constructed within the constraints of the Solar Decathlon, with an emphasis on sustainability. It used several filtration methods, including micron, mineral sand, activated carbon, and ultraviolet disinfection. Multi-phase water testing was conducted to evaluate pH, turbidity, chemical oxygen demand, total organic carbon, and total nitrogen. The prototype proved capable of functioning in a real-world setting and filtering water to meet several non-potable urban reuse standards.Item ALTERNATIVE SUBSTRATES FOR RESTORATION OF THE CHESAPEAKE BAY’S EASTERN OYSTER, CRASSOSTREA VIRGINICA: AN EVALUATION USING ADDITIVE MANUFACTURING AND ELECTROLYSIS MINERAL ACCRETION(2019) Arrington, Myles; Auerbach, Aaron; Gold-Pastor, Nellie; Mengers, Nathan; Schiksnis, Cara; Simon, Caroline; Paynter, KennedyOver the past century, the population of the Chesapeake Bay’s eastern oyster, Crassostrea virginica, has collapsed dramatically, endangering the ecology of the bay and economy of the surrounding area. Declining shell numbers limit the growth of current oyster populations and have led to the use of alternative substrate material as a method for oyster restoration. Motivated by successful coral reef restoration efforts and the emerging field of additive manufacturing, we tested the use of electrolysis mineral accretion and Fused Deposition Modeling (FDM) to create artificial substrate for oyster spat settlement and survival. To start, we employed electrolysis mineral accretion with the goal of creating a sustainable and adequate amount of calcium carbonate (CaCO3) substrate. Mineral accretion rates were restrictive in our closed system, and we were unable to create sufficient substrate to test settlement. Second, we used 3D scanning and FDM to print artificial oyster shells identical to their natural counterparts, using a filament containing CaCO3. Using 3D printed oyster shells, we tested the importance of physical structure versus the presence of intrinsic biochemical cues in oyster settlement rates. Our results indicated that the oyster spat did not achieve significant survival on the printed material. Similarly, the use of the biochemical cue L-DOPA was insufficient in encouraging larval settlement on printed shells, indicating the significant role played by the underlying shell composition. The results indicate that the biochemical properties of the substrate take precedence over the geometric similarity to natural shells, a finding which should guide future methodology in oyster restoration.Item VARIABLE FENESTRATION OF A 3D NANOPRINTED LIVER SINUSOID ON A CHIP(2019) Brainerd, Cara; Gorti, Viswanath; Janes, Morgan; Jones, Katherine; Khayat, Shireen; Liu, Andrew; Noonin-Shueh, Madeleine; Rao, Sahana; Sochol, Ryan D.Here we report a novel strategy for engineering liver sinusoids with designed fenestrae that yield near uniform microfuidic flow conditions along the length of the microstructure - capabilities enabled by the use two-photon direct laser writing (DLW). To better model organ systems, researchers have increasingly investigated the use of DLW as a promising means for mimicking both architectures and length scales of physiological components. DLW-based approaches could enable liver sinusoids to be recreated in vitro; however, recent efforts to construct permeated tubules exhibit dramatic decreases in fluid flow through the pores downstream. To overcome such issues, here we applied microfluidic circuit theory and in-situ DLW (isDLW) to manufacture liver sinusoids that included fenestrae with distinct sizes to better maintain a consistent fenestra-specifi c flow profi le. Specifically, fenestrae radii were increased from 0.75 μm to 2.01 μm over the length of a 510-μm sinusoid. Theoretical results revealed that the flow rate through the fenestrae could be more maintained along the length of the optimized sinusoid versus the unoptimized sinusoid with uniform fenestrae which results in inconsistent fluid flow. Preliminary results revealed successful isDLW fabrication of the optimized sinusoid, with proof-of-concept microfluidic flow demonstrations that suggest that the presented strategy could benefit numerous biomedical applications. These results suggest the potential of this design strategy for liver on-a-chip modeling, and given the numerous anatomical structures similar to the presented fenestrated sinusoid, this approach could be extended to model additional organ systems of the body for disease modeling and drug screening.Item AN IMMERSIVE EXPERIENCE: VISUALIZING LARGE-SCALE CLIMATE DATA USING VIRTUAL REALITY AND INFRARED HAND-TRACKING TECHNOLOGY(2019) Corrales, Theodore; Estes, Erin; Ho, Kevin; Hom, Austin; Muthupari, Mughilan; Pan, Justin; Shen, Justin; Penny, StephenRecently, interest in understanding Earth’s climate has risen in light of anthropogenic climate change. However, effective climate data visualization tools for studying climate remain largely outdated.We proposed the use of virtual reality to more effectively visualize climate data, implemented a prototype climate visualization tool using Unreal Engine, and conducted a focus group to gain expert insight and advice for evaluating and improving our visualization tool. Our regional view displayed the temperature of the Chesapeake Bay, surrounded by topographic data in one cohesive visualization, while our global view transformed and displayed climate data on a virtual globe using a perceptually-uniform color texture and incorporated an animated particle field to visualize vectorized data. Finally, we used the Leap Motion Controller to facilitate interaction with the visualizations through hand gestures. Overall, participants found that three-dimensional visualizations were more intuitive than two-dimensional visualizations and suggested areas for further improvement in the future.Item SUSTAINABLE LOW ENERGY DESALINATION OF ROAD SALT RUNOFF USING ION EXCHANGE RESINS(2019) Bandyopadhyay, Surjo; Firer, Danielle; Hamilton, Amanda; Krasnoff, Gregory; Kraus, Harrison; McKenna, Eric; Quartner, Evan; Umeozulu, Somachukwu; Brubaker, KayeNaCl is used to deice roads during winter storms, but the resulting salty runoff has detrimental environmental effects. A novel low-energy approach for desalinating snowmelt runoff using ion exchange resins was explored. Strong-acid cation and strong-base anion resins were tested in parallel gravity flow columns to determine their efficacy in removing Na+ and Cl− from saline solutions of varying concentrations (0%, 1%, 5%, 10% w/w). Ion exchange was quantified via pH measurements of column effluent samples. Cation resin capacity was positively correlated with influent Na+ concentration, while removal efficiency was negatively correlated with Na+ concentration. Neither the anion resins’ capacity nor removal efficiency followed any correlation with Cl− concentrations. More 1% influent solution compared to 5% or 10% was required to exhaust both resins. Future research should confirm current findings, test resins in realistic field conditions, explore resin regeneration, and examine engineering efficacy in a field setting.