<p>A key aspect of color change is altering perceived value or intensity. This dissertation presents a methodology to achieve value change through mechanical means via the deflection of bistable structures. We create the Mechxel, two methods of mechanical pixel-based, reversible color change using 3D printed switchable multistability and bistable switch panels that augment the projected area a viewer perceives which enables the creation of image and character tessellation.</p> <p>Switchable multistability (SMS) arises from the combination of pre-strain and shape memory, allowing us to access multiple elastically programmed shapes at elevated temperatures with fast morphing and low actuation forces, while retaining high stiffness at room temperature. We design and manufacture SMS Mechxels using fused deposition modeling (FDM) 3D printing on the Ultimaker 3D printer in a bilayer layup of polylactic acid (PLA) with a [90/0] print direction while iteratively miniaturizing the physical size to enhance the resolution while also reducing the size of the overall tessellated display. Leveraging SMS properties programmed into each Mechxel, the projected area to a viewer will vary between the unit’s stable states, creating a difference in perceived value of coloration due to changes in area. To ease the tessellation process, we also introduce a tessellation user interface that maps images to their tessellated equivalent to reduce tessellation trial and error. This interface also calculates the number of Mechxels required in their respective states and the final physical size of the display. We then carry out image processing to justify this change in value between stable states and run preliminary optical character recognition.</p> <p>Inspired by mechanical bistable mechanisms, the bistable switch Mechxels utilize changes in a surface’s projected area to a viewer via changes in the angle of a bistable tile using a 5-by-5 grid for character replication and display. Comprising of three main components – two bistable switches, a colored tile and a base, design considerations were made to create an easy to assemble and replaceable 3D printed grid system that could be interacted with by audiences or easily electromechanically actuated. Using pixel-by-pixel comparisons and Sorensen-Dice coefficient, characters using the typeface Silkscreen were documented on these tiled grids yielding high similarity and low error when compared to their digital reference images in various positions and orientations. We also experiment with transitional waves as a promising means of actuation to change the Mechxel between their stable states.</p> <p>The Mechxels considered in this research introduce a new means of purely mechanical color change, character, and image display either leveraging the elastic properties of shape memory polymers (SMPs) or bistable mechanisms. With potential applications in passive morphing architecture, adaptive camouflage, and interactive aesthetic, Mechxels opens the door to limitless design possibilities through a new perspective into color change.</p>

Engineering designers commonly make sequential information acquisition decisions such as selecting designs for performance evaluation, selecting information sources, deciding whom to communicate with in design teams, and deciding when to stop design exploration. There is significant literature on normative decision making for engineering design, however, there is a lack of descriptive modeling of how designers actually make information acquisition decisions. Such descriptive modeling is important for accurately modeling design decisions, identifying sources of inefficiencies, and improving the design process. To that end, the research objective of the dissertation is to understand how designers make sequential information acquisition decisions and identify models that provide the best description of a designer’s decisions strategies. For gaining this understanding, the research approach consists of a synthesis of descriptive theories from psychological and cognitive sciences, along with empirical evidence from behavioral experiments under different design situations. Statistical Bayesian inference is used to determine how well alternate descriptive decision models describe the experimental data. This approach quantifies a designer's decision strategies through posterior parameter estimation and Bayesian model comparison. <br><br>Two research studies, presented in this dissertation, focus on assessing the effects of monetary incentives, fixed budget, type of design space exploration, and the availability of system-wide information on information acquisition decisions. The first study presented in this dissertation investigates information acquisition by an individual designer when multiple information sources are available and the total budget is limited. The results suggest that the student subjects' decisions are better represented by the heuristic-based models than the expected utility(EU)-based models. <br>While the EU-based models result in better net payoff, the heuristic models used by the subjects generate better design performance. The results also indicate the potential for nudging designers' decisions towards maximizing the net payoff by setting the fixed budget at low values and providing monetary incentives proportional to the saved budget.<br><br>The second study investigates information acquisition through communication. The focus is on designers’ decisions about whom to communicate with, and how much to communicate when there is interdependence between subsystems being designed. This study analyzes team communication of NASA engineers at a mission design laboratory (MDL) as well as of engineering students designing a simplified automotive engine in an undergraduate classroom environment. The results indicate that the rate of interactions increases in response to the reduce in system-level design performance in both settings. Additionally, the following factors seem to positively influence communication decisions: the pairwise design interdependence, node-wise popularity (significant with NASA MDL engineers due to large team size), and pairwise reciprocity.<br><br>The dissertation work increases the knowledge about engineering design decision making in following aspects. First, individuals make information acquisition decisions using simple heuristics based on in-situ information such as available budget amount and present system performance.<br>The proposed multi-discipline approach proves helpful for describing heuristics analytically and inferring context-specific decision strategies using statistical Bayesian inference. This work has potential application in developing decision support tools for engineering design. Second, the comparison of communication patterns between student design teams and NASA MDL teams reveals that the engine experiment preserves some but not all of the communication patterns of interest. We find that the representativeness depends not on matching subjects, tasks, and context separately, but rather on the behavior that results from the interactions of these three dimensions. This work provides lessons for designing representative experiments in the future.

<p>Engineering engagement programs use service learning and community engagement pedagogies that require a real-world situated problem in which the community partners who experience those problems are integral to those spaces. Despite community partners being integral to engineering engagement programs, research on community partner perspectives is vastly unrepresented in literature Therefore, the goal of this work is to investigate engineering engagement programs from the perspective of the community partners by answering the research question: what meaning do community partners make of their experience in engineering engagement programs? This study describes a qualitative research inquiry in which interviews with three community partners from three different engineering engagement programs were conducted and analyzed for community partner meaning. Using a framework developed by Zittoun and Brinkmann for meaning making, this study presented several themes associated with pragmatic, semantic, and existential meanings made by community partners within this study (2012).</p><p>Findings from this study suggest implications for expansions of existing frameworks of constituents and components of engineering engagement programs, as well as potential opportunities to more deeply engaging community partners the assessment of student contributions and trajectories as a function of participation in EEPs. Additionally, findings from this study suggest an opportunity to investigate communication and thinking between students and community partners to better support the experience of the community partner (and potentially, the learning of the students). Lastly, findings from this study suggest that participation in EEPs presents the opportunity for community partners to learn by doing which can be more deeply investigated to begin addressing the gap in the literature associated with community partners in research on engineering engagement spaces.</p>

The facilitator model for dual credit offers a way for student to earn directly transcripted credit to colleges and universities, overcoming many barriers faced by other dual credit models. Successful implementation of this model requires high degree of involvement from the cooperating institution. This IRB approved qualitative case study explored the needs of five teacher facilitators in both summer professional development and on-going support throughout the school year when implementing a facilitator model for dual credit with open-ended design coursework. Code-recode and axial coding techniques were applied to over 90 hours of transcribed data, artifacts, and observations from a seven month period to find emerging themes and offer recommendations for implementation.

<div> <p>A residential botanical air filtration system (Biowall) to investigate the potential for using phytoremediation to remove contaminants from indoor air was developed. A full scale and functioning prototype was installed in a residence located in West Lafayette, Indiana. The prototype was integrated into the central Heating, Ventilating, and Air Conditioning (HVAC) system of the home. This research evaluated the Biowall operation to further its potential as an energy efficient and sustainable residential air filtration system.<br></p> <p> </p> <p>The main research effort began after the Biowall was installed in the residence. A field evaluation, which involved a series of measurements and data analysis, was conducted to identify treatments to improve Biowall performance. The study was conducted for approximately one year (Spring 2017-Spring 2018). Based on the initial data set, prioritization of systems in need of improvement was identified and changes were imposed. Following a post-treatment testing period, a comparison between the initial and final performances was completed with conclusions based on this comparison. </p> <p> </p> <p>The engineering and analysis reported in this document focus on the air flow path through the Biowall, plant growth, and the irrigation system. The conclusions provide an extensive evaluation of the design, operation, and function of the Biowall subsystems under review.</p> </div> <br>