Wu Student Presentation Competition March 29, 2019, 9 am in room H-111, reception to follow in the library
2019 WSPC Student Abstracts
Pulsed laser deposition of layered thin films for medical imaging
A thin-film, storage phosphor plate has been developed containing multiple transparent layers of orthorhombic phase barium chloride nanocrystals doped with europium, separated by nano-layers of a host glass. These transparent films are synthesized by pulsed laser deposition using a composite target. Manipulation of target movement allows for precision control of layer composition. This synthesis method can result in a higher concentration of luminescent centers compared to glass ceramic plates synthesized via the melt-quench method. Heat treatments were necessary to ensure the barium chloride is present in the orthorhombic phase. Performance characteristics of these films will be reported.
Background Oriented Schlieren
Invented just before the turn of the 21st century, Background Oriented Schlieren (BOS) is an optical diagnostic technique that has recently gained prominence within the aerospace community. BOS is simple to set up, requiring only a camera, a background containing a randomized dot pattern, and a light source. The technique quantifies the density gradients across a test region by imaging background distortions caused by changes in the index of refraction within the test media. The development, implementation, and usage of the BOS technique are presented and compared to other optical diagnostics more commonly used at UTSI.
Initial Characterization of a Hypersonic Boundary-Layer Transition with Quantitative Optical Flow Diagnostics
Boundary-layer transition on hypersonic flows represents a primary national research interest, due to its extreme effect on surface heating on a hypersonic vehicle. Experimental data characterizing the state of the boundary layer is required to validate modeling and design efforts; however, this data is historically difficult to gather without intrusive diagnostics, which may disturb flow to a non-negligible extent. In this study, optical flow diagnostics are used to characterize the state of the boundary layer on an axisymmetric model in Mach 4 flow. This preliminary work supports a future study of the dynamics of transitional shock/boundary layer interactions.
Investigation of Unsteady Pressure Loads Generated by Swept Shock-wave/Boundary-layer interactions using Unsteady Pressure-sensitive Paint
An investigation of fin-induced swept shock-wave/turbulent boundary-layer interactions (SWTBLI) is underway in order to characterize the influence of gaps between the fin and tunnel surface representative of a realistic control surface installation. Unsteady pressure loads generated by shock/boundary layer interactions associated with these configurations are notorious for posing a threat to the structural integrity of hypersonic vehicles. Unsteady pressure-sensitive paint (uPSP) will be used to provide a global pressure distribution around and under a fin model installed in a Mach 2 wind tunnel to explore the evolution of the interaction with varying surface gap scale.
Synthesis and Characterization of Iron Nanoparticles for Biomedical Applications
Magnetic nanoparticles have many biomedical applications including drug delivery, theranostic and hyperthermia treatments, and as magnetic resonance imaging (MRI) contrast agents. Due to their higher magnetic saturation, monometallic iron nanoparticles have an edge over the current industry standard – iron oxide nanoparticles. Monometallic iron nanoparticles were synthesized through a reduction reaction before being coated for biocompatibility. Transmission electron microscopy (TEM), dynamic light scattering (DLS), and Mossbauer spectroscopy were utilized to characterize the coated and uncoated iron nanoparticles. Stability and relaxivity experiments of the as-made nanoparticles were performed to evaluate their potential use as an MRI contrast agent.
The Dynamic Stability of Satellite Formations in Planetary Orbital Environments.
The stability of dynamically networked formations is at the heart of the science of autonomy. It is paramount for the system to have the ability to detect unstable interactions early and compensate or stabilize them before they disrupt the operation of the fully networked formation. This presentation will use a system of satellites in passive relative orbits (PROs), to show that instabilities can arise from closed chain virtual connections between stable members. The presentation will also discuss the use of adaptive-key-component controllers as stability restoring devices.
Estimating Onset Voltage for High and Low Aspect Ratio Electrospray Emitters
An important part of the design process of electrospray emitters is the ability to arrive at preliminary estimates of onset voltage for given geometries. Much previous work has relied on equations derived for a theoretical geometry that is often not similar to that used in practice. The research presented here focuses on determining the onset voltage of emitter needles whose aspect ratios are either sufficiently small or large to cause a significant deviation from this prediction. Simulations have been performed on both single and arrays of emitters in an attempt to form a more generalized estimate of emitter onset voltage.
Computational Study of Controlled Laminar Separation Effects on Transition
Laminar-turbulent transition is a source of unsteadiness and a design driver for high speed vehicles. Thus, there is significant interest in the influence of laminar separation bubbles on the transition process. Assisting with this interest, the present work is designing an experimental base configuration exhibiting well-behaved boundary layer growth with no separation at the tip and limited separation elsewhere along the body using the finite volume solver HPCMP CREATEâ„¢ Kestrel. More details will be provided pending release by AFOSR.
Highly Resolved, Multi-Aspect Analysis of a Mach 1.5 Jet
The flowfield of a supersonic jet is typically characterized as having regions with shocks and expansion waves, viscous and inviscid flow, and regions with high shear and vorticity. Studying this type of flow requires measurement techniques with high spatial and temporal resolution, sensitivity, and dynamic range. Ultra-high speed (~100,000 fps) Schlieren imaging is used to study the flow exhausting from a Mach 1.5 nozzle at various supply pressures. A detailed analysis using several techniques will be presented, and the data quantified from the flow visualizations will be compared with archival results from conventional measurements.
Vortex Generators as Passive Flow Control on a Crossing Shock-Wave/Boundary-Layer Interaction
High-speed air-breathing vehicles are a current topic of research interest and are a common area where shockÂ-wave/boundary-layer interactions occur. The Inlet geometry of such a vehicle is represented in this experiment with two sharp fins to create a crossing shock-wave/boundary-layer interaction. To examine inlet performance, vortex generators are being investigated as a form of passive flow control to reduce separation and increase inlet performance. These micro-vortex generators, which are a sub boundary-layer height, are mounted on the surface of the test section and are being investigated using oil flow, high-speed Kulites, and infrared thermography.
Synthesis and Testing of Sodium and Iron Based Compounds for Use as Ion Battery Cathodes
As the demand for ion batteries grows, a more cost effective ion battery is needed in order to keep ion battery prices at their current level. To achieve this, we propose that the lithium and cobalt currently used in commercial battery cathodes be replaced with sodium and iron. These elements are cheaper, more abundant, and have the potential to achieve similar levels of performance to commerciallithium based cathodes. We have synthesizeq aru:f tested several sodium and iron based compounds for use as ion battery cathode material in an effort to make a competitive sodium ion battery.