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Solar Thermal Adsorption Refrigerator
Clayton Douglas Rosso, Quinn T. Whisler
The Solar Thermal Absorption Refrigerator (STAR) uses no electricity to cool refrigerated items including vaccines and perishable food to be used in remote areas with unreliable electricity. This process exploits adsorptive refrigeration using ethanol and activated carbon. Evaporative cooling of ethanol under vacuum takes heat away from the refrigerated objects turning the liquid ethanol into vapor. The ethanol gas absorbs onto activated carbon. During the desorption process, heating the activated carbon evaporates the ethanol which condenses to start the cycle over again. The system runs adsorption and desorption to create a refrigeration cycle. After sitting dormant for multiple years, the STAR apparatus was repaired and tested to determine whether or not the working pair of ethanol and activated carbon is viable. The first part of the cycle, adsorption, was evaluated for the amount of ethanol evaporated and the lowest working temperature. Tests running desorption were conducted to determine the amount of ethanol returned. The group tested multiple treatment procedures to remove possible contaminants on the activated carbon. SEM imaging and SDT testing were performed on the activated carbon to determine the concentrations of contaminants and how they affect heating and cooling of the carbon.
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Spectral Control in Bandpass Filters Using Dispersion Relations in Metallo-dielectric Structures
Guo Chen
In previous work, we introduced an analytical approach that utilizes the dispersion relation within an infinite periodic multilayer structure to predict the performance of finite multilayer structures. We validated the accuracy of our predictions by demonstrating numerical agreement with other established simulation methods, such as the transfer matrix method, and through experimental confirmation using fabricated multilayer metallo-dielectric structures. In this work, we employ dispersion relations to illustrate that metallo-dielectric (MD) structures, as opposed to a multilayer dielectric-dielectric (DD) structures, efficiently yields a sharp-edge transmittance spectrum profiles, and provides convenient control over both sides of the bandpass cut-off edges. Our approach also enables the calculation of effective permittivity without relying on traditional homogenization techniques. Furthermore, based on the predicted frequency response from dispersion relations and through the introduction of dielectric gaps between two identical 3-layer MDM structures, we demonstrate, using the transfer matrix method, the potential for further engineering the transmittance spectrum of bandpass filters in the visible and near-IR. The capability to achieve a sharp-edge filter with a limited number of layers further underscores the cost-effectiveness of such bandpass filters.
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Sub-Wavelength Waveguide Michelson Interferometer Sensors
Kurugamage Nuwan Asela Perera
We experimentally demonstrated an asymmetric path enhanced Michelson interferometer sensor with subwavelength waveguides in a silicon-on-insulator (SOI) platform with bulk sensitivity ~775nm/RIU. Numerical simulations indicate feasibility to achieve high sensitivity ~70,000nm/RIU in optimized device geometries. Phase sensitivity is recorded as 72,678 rad/RIU. cm for biotin-streptavidin conjugate detection. By monitoring intensity changes in interferometers, our device can potentially reach a limit of detection of 1.1×10-6 RIU.
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Surface Reinforcement Strategies for Polymer-based 3D Printing with Industrial Robotic Arm
Ajith Kumar Veeraboina
Additive manufacturing (AM) technology is rapidly advancing across diverse fields. For instance, the use of robotic arms in various AM processes has led to significant gains in printing flexibility and manufacturing scalability. However, despite these advancements, there remains a notable research gap concerning the mechanical properties of parts 3D-printed with robotic arms. This study focuses on developing a robotic fused filament fabrication (FFF) 3D-printing process with a layer resolution of 50 μm to 200 μm. We propose a novel planar tool path strategy that can vary contour layer thickness within an infill layer to improve mechanical strength by minimizing air gaps between contours. SEM images suggest this new tool path strategy leads to a meaningful reduction in void area fraction within contours, confirmed by a nearly 6% increase in ultimate tensile strength. In addition, we also propose a strategy for creating a non-planar tool path along axial direction for thin-shell 3D models, utilizing planar slicing. This strategy includes segmentation of the point cloud and printing non-planar layers on top of the printed planar layers in a systematic order. This approach might guarantee bonding between deposited polymer paths in different directions. Therefore, yields a significant improvement in mechanical properties.
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The Effects of Fatigue on Landing Forces in Competitive Female Irish Dancers
Anna Robinson
Lower extremity injuries are highly prevalent within the Irish dance population, yet research surrounding potential determinants is scarce. Many movements, particularly jumps, in Irish dance are constituted by a one-foot landing with the ankle in a plantarflexed position and the knee fully extended. This unique landing technique is contrary to other forms of dance, such as ballet, where landings typically allow for some knee flexion in a plie-like position. Subsequently, this aesthetic constraint requires large amounts of strength and balance, in addition to forcing the structures of the foot and ankle to absorb the entire shock of the landing. This study aims to determine the effect that fatigue has on landing forces following the 360 spin move, which is characterized by the dancer jumping off the ground from their lead foot, making a full 360° turn in the air before landing on the opposite foot. Since fatigue has been shown to play a role in ground reaction force, in addition to overall center of pressure, this study focuses on establishing how the lower extremities react when trying to stop the turning motion following this jump. Through having competitive female Irish dancers perform the 360 spin under both fatigued and non-fatigued trials with all landings taking place on a force plate, the changes in ground reaction force and center of balance can be determined. The results from this study will be able to direct future research in establishing additional injury risks associated with the Irish dance technique in order to correctly aim injury prevention measures.
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Thermal 3D Point Cloud Generation and Model Reconstruction for Energy Auditing
Qingyu Ren
Maintaining efficient energy usage in buildings or infrastructure is vital to the sustainable development program. The infrared (IR) thermography technique is widely used in thermoelastic behavior analysis and contactless temperature detection. However, the current thermal information is restricted in 2D space (i.e., image), depth and geometric information of the construction is missing. Geometric information and thermodynamics in the 3D space of building or infrastructure are essential for building energy auditing and infrastructure defect inspection. Though LiDAR is a possible solution, its costs, portability, and difficulty in merging additional data may bring more challenges to users. The aim of this project is to generate 3D RGB-IR point cloud models through monitoring over time, then the model can be used for simulation and energy consumption analysis and further applied in emergency response or city thermal behavior analysis. In recent years with advancements in computer vision, and the improvement of computation, structure from motion became an active method in 3D optical imaging. On the other hand, thermal cameras have low resolution compared with RGB cameras, we propose to map thermal information onto 3D reconstructed model. Efficiently and effectively merging 3D point clouds constructed from RGB images collected by ordinary cameras and corresponding infrared images from a co-calibrated thermal imager. This effort is cutting-edge and crucial as low-cost, accurate, and portable 3D thermal reconstruction solutions have significant potential in building energy auditing and infrastructure inspection/maintenance.
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Using MotionGen to Help Teach Concepts from Machine Theory
Luke C. Lococo, Kahra Gikanga Loding, Ryan Joseph Rotsching, Benjamin Michael Schaiper
Researchers in Mechanical Engineering at SUNY Stony Brook have recently developed a free-access, online tool called MotionGen which enables users to virtually synthesize and assemble 2-dimensional mechanisms. Designers can then animate the mechanisms and observe the motion to assess performance. The course MEE 321 Theory of Machines, a requirement in the University of Dayton Mechanical Engineering curriculum, focuses on the analysis and use of these systems. MotionGen provides a new resource for bringing the static images from that course's content to life via animations. MotionGen assists students in gaining exposure to functioning mechanisms by helping visualize how linkages move, thus building a stronger understanding of the fundamental concepts for the course. A student team has created a significant number of short videos which range from simple mechanisms in motion to example videos breaking down complicated concepts like the “seize and fix” methodology for assessing degrees of freedom.
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