Aerospace Engineering Commons^™

Computational Analysis Of Nanostructures Formed In Molten Salt Nanofluids, Vidula B. Pawar

Mechanical and Aerospace Engineering Theses - Archive

Meeting the continuously increasing demand of `clean' energy is the biggest challenge of the energy research field. Amongst the many renewable sources of energy, energy from the Sun is one of the biggest sources in the form of light and heat. Photovoltaic cells and concentrated solar power are few of the solar energy harnessing technologies. Photovoltaic cells use semiconductor materials to directly convert energy from sun into electricity. CSP uses a combination of solar receivers (mirrors or lenses) to concentrate the solar thermal energy which is further converted into electricity using the common thermodynamic cycle. One of the Photovoltaic (PV) …

Thermo-Mechanical Feasibility Study Of Copper And Gold Wirebonds In 3d Electronic Package, Gaurang Naware

Mechanical and Aerospace Engineering Theses - Archive

3 Dimensional (3D) Electronics Packaging has emerged as a revolutionary trend in the micro-electronics industry. It has made possible cost-effective system integration and size scaling while reducing the interconnect delay. The ever increasing demand for better mechanical, thermal, electrical performance, improved reliability and cost effective semiconductor manufacturing technology has encouraged the engineers to replace Gold (Au) by Copper (Cu). In a survey conducted by Semiconductor Equipment and Materials International, to study the industry mood related to wirebond technology, it was observed that 72% of the leading semiconductor companies are considering switching to Cu [1]. The only major concern regarding the …

Fabrication Of Superhydrophobic Polystyrene Surfaces With Tunable Adhesion By Modulating Strain Recovery Temperature, Prasha Sarwate

Mechanical and Aerospace Engineering Theses - Archive

In this work, different superhydrophobic structures were fabricated on the surfaces of polystyrene (PS) blocks, using oxygen reactive ion etch (ORIE) and controllable strain recovery. The PS used here is a thermal shape memory polymer (SMP). Microhills are first generated on the surface of a PS block by ORIE. The PS block is then heated up, which triggers the strain recovery. During this process of recovering its original shape, the PS block gradually reduces its lateral dimensions, while increasing its thickness. Using different recovery temperatures, the surface morphologies can be controlled, which provides an approach to adjust surface wetting properties, …

Rfbr: Radio Frequency Beacon Receiver, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

The Space Dynamics Laboratory at Utah State University (SDL/USU), the Air Force Space and Missile Systems Center (SMC), and the Air Force Research Laboratory (AFRL) have teamed together to provide a portable ground-based radio frequency beacon receiver (RFBR) system capable of characterizing ionospheric parameters, including total electron content (TEC), amplitude, and phase scintillation. The system, derived almost entirely of COTS parts, can be configured to receive RF beacons such as those transmitted by existing on-orbit Coherent Electromagnetic Radio Tomography (CERTO) instrumentation, the upcoming Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC2), or other frequencies from VHF to S-band. By …

Comparative Analysis Of Gps Data, Kiel Von Lindenberg

Undergraduate Journal of Mathematical Modeling: One + Two

The goal of this project is to calculate the distance traveled during a bike ride around the University of South Florida using information gathered by a GPS (Global Positioning System) application on a smartphone. We calculate the route distance in two ways: from latitudes and longitudes using the haversine formula and 2) from velocities and times using the trapezoidal rule. These computed distances were compared to the distance given by the smartphone application.

Rocket Flight Path, Jamie Waters

Undergraduate Journal of Mathematical Modeling: One + Two

This project uses Newton’s Second Law of Motion, Euler’s method, basic physics, and basic calculus to model the flight path of a rocket. From this, one can find the height and velocity at any point from launch to the maximum altitude, or apogee. This can then be compared to the actual values to see if the method of estimation is a plausible. The rocket used for this project is modeled after Bullistic-1 which was launched by the Society of Aeronautics and Rocketry at the University of South Florida.

Tacot V3.0, Jean Lachaud, Tom Van Eekelen, Daniele Bianchi, Alexandre Martin

Ablation Workshop: Code Comparison

No abstract provided.

Energy Deposition Into Heavy Gas Plasma Via Pulsed Inductive Theta-Pinch, Ryan Alan Pahl

Doctoral Dissertations

"The objective of this research is to study the formation processes of a pulsed inductive plasma using heavy gases, specifically the coupling of stored capacitive energy into plasma via formation in a theta pinch coil. To aid in this research, the Missouri Plasmoid Experiment Mk. I (and later Mk. II) was created.

In the first paper, the construction of differential magnetic field probes are discussed. The effects of calibration setup on B-dot probes is studied using a Helmholtz coil driven by a vector network analyzer and a pulsed-power system. Calibration in a pulsed-power environment yielded calibration factors at least 9.7% …

Control Design And Performance Analysis For Autonomous Formation Flight Experiments, Caleb M. Rice

Graduate Theses, Dissertations, and Problem Reports (ETD)

Autonomous Formation Flight is a key approach for reducing greenhouse gas emissions and managing traffic in future high density airspace. Unmanned Aerial Vehicles (UAV’s) have made it possible for the physical demonstration and validation of autonomous formation flight concepts inexpensively and eliminates the flight risk to human pilots. This thesis discusses the design, implementation, and flight testing of three different formation flight control methods, Proportional Integral and Derivative (PID); Fuzzy Logic (FL); and NonLinear Dynamic Inversion (NLDI), and their respective performance behavior. Experimental results show achievable autonomous formation flight and performance quality with a pair of low-cost unmanned research fixed …

Fault-Tolerant Trajectory Tracking Of Unmanned Aerial Vehicles Using Immunity-Based Model Reference Adaptive Control, Brenton K. Wilburn

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation presents the design, development, and simulation testing of an adaptive trajectory tracking algorithm capable of compensating for various aircraft subsystem failures and upset conditions. A comprehensive adaptive control framework, here within referred to as the immune model reference adaptive control (IMRAC) algorithm, is developed by synergistically merging core concepts from the biologically- inspired artificial immune system (AIS) paradigm with more traditional optimal and adaptive control techniques. In particular, a model reference adaptive control (MRAC) algorithm is enhanced with the detection and learning capabilities of a novel, artificial neural network augmented AIS scheme. With the given modifications, the MRAC …

Airmen With Mild Traumatic Brain Injury (Mtbi) At Increased Risk For Subsequent Mishaps, Casserly R. Whitehead, Timothy S. Webb, Timothy S. Wells, Kari L. Hunter

United States Air Force: Publications

Background: Little is known regarding long-term performance decrements associated with mild Traumatic Brain Injury (mTBI). The goal of this study was to determine if individuals with an mTBI may be at increased risk for subsequent mishaps. Methods: Cox proportional hazards modeling was utilized to calculate hazard ratios for 518,958 active duty U.S. Air Force service members (Airmen) while controlling for varying lengths of followup and potentially confounding variables. Two non-mTBI comparison groups were used; the second being a subset of the original, both without head injuries two years prior to study entrance. Results: Hazard ratios indicate that the causes of …

Fabrication Of Glass Fiber-Reinforced Transparent Composites Using Vacuum Assisted Resin Transfer Molding Process, Gregory A. Taylor

Masters Theses

"The most commonly used transparent material is glass. Traditionally, glass is not desired for applications involving a low weight material while preserving high strength such as aerospace and military applications where armor must also be transparent. Some applications may include aircraft canopies and other vehicle windows. Development of a reliable transparent composite would fill a need for many of these applications where a transparent structure must both be strong and lightweight. A transparent polymer reinforced with a glass fiber fabric is a viable solution. To ensure transparency, both fiber and matrix must match in refractive index.

In the present work, …

Parametric Scramjet Analysis, Jongseong Choi

Electronic Theses and Dissertations

The performance of a hypersonic flight vehicle will depend on existing materials and fuels; this work presents the performance of the ideal scramjet engine for three different combustion chamber materials and three different candidate fuels. Engine performance is explored by parametric cycle analysis for the ideal scramjet as a function of material maximum service temperature and the lower heating value of jet engine fuels. The thermodynamic analysis is based on the Brayton cycle as similarly employed in describing the performance of the ramjet, turbojet, and fanjet ideal engines. The objective of this work is to explore material operating temperatures and …

Relative Motion Guidance, Navigation And Control For Autonomous Orbital Rendezvous, Mohamed Okasha, Brett Newman

Mechanical & Aerospace Engineering Faculty Publications

In this paper, the dynamics of the relative motion problem in a perturbed orbital environment are exploited based on Gauss’ variational equations. The relative coordinate frame (Hill frame) is studied to describe the relative motion. A linear high fidelity model is developed to describe the relative motion. This model takes into account primary gravitational and atmospheric drag perturbations. In addition, this model is used in the design of a control, guidance, and navigation system of a chaser vehicle to approach towards and to depart from a target vehicle in proximity operations. Relative navigation uses an extended Kalman flter based on …

Multi-Criteria Decision Making Based On Dsmt-Ahp, Jean Dezert, Jean Marc Tacnet, Mireille Batton-Hubert, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper, we present an extension of the multicriteria decision making based on the Analytic Hierarchy Process (AHP) which incorporates uncertain knowledge matrices for generating basic belief assignments (bba’s). The combination of priority vectors corresponding to bba’s related to each (sub)- criterion is performed using the Proportional Conflict Redistribution rule no. 5 proposed in Dezert-Smarandache Theory (DSmT) of plausible and paradoxical reasoning. The method presented here, called DSmT-AHP, is illustrated on very simple examples.

Improving Scoliosis Rehabilitation, Ryan Neufeld

Mechanical and Aerospace Engineering Theses - Archive

Scoliosis, a disease that mainly affects children, is a deformity of the spinal column in all three dimensions. Treatment for scoliosis aims at straightening the spine with minimal discomfort to the patient. Current treatments involve wearing a polymeric brace that based on its design, exerts force on the spine in order to straighten it. The shape of the brace and the locations where the brace should apply forces are defined based on the experience of the orthotics specialist. Currently used braces are not equipped with sensors to monitor the loads generated and possibly aid in the rehabilitation process. The rehabilitation …

Computational Study Of Data Center Hotspot Mitigation With Snorkels As An Alternative Rack-Level Containment Strategy, Chris Onyiorah

Mechanical and Aerospace Engineering Theses - Archive

One of the major concerns of companies around the world is business continuity and with that comes the need to prevent operational dysfunction by keeping their information systems available and functional. IT professionals therefore, are constantly striving towards network sustainability by boosting the cooling cycle and infrastructure in data centers, while also reducing overall energy consumption. The combination of increasing IT workloads and packaging densities place stringent requirements on data center cooling systems and so, various traditional airflow management technologies have been implemented that propose significant energy savings and potential reduction in net annual cost for running data centers.In this …

Data Center Cooling Augmentation Using Micro-Encapsulated Phase Change Material, Ruddhi Shashikumar Deshmukh

Mechanical and Aerospace Engineering Theses - Archive

The ever increasing information technology heat load and data center cooling energy are the main reasons to investigate the performance of microencapsulated phase change slurry over other heat transfer fluids. In recent years, more effort is being made on the development of a new technique to use the phase change materials as pump-able heat transfer fluid and as heat storage system. Thermal Energy Storage (TES) using Phase Change Materials for data centers offers a very effective method of cutting electric power costs for owners and easing demand on the power grid. Thermal storage systems have been around for decades and …

Phoresis Of A Solid Particle In Real Fluid, Yuan Ting Wu

Mechanical and Aerospace Engineering Dissertations - Archive

For micro- and nano-scale particles driven by interfacial non-contact forces in fluid, known as phoresis, this dissertation provides a general formulation and a systematic investigation. It starts with an analytical continuum-mechanics formulation that covers various important aspects of an interfacial structure, including viscosity and mass density variations as well as a body force field, in real fluid. It then reduces to specific solutions due to characteristic mechanisms. A closed-form analytical solution to the case of viscosity variation (which manifests itself as Navier's slip boundary condition) is derived. Furthermore, a novel mechanism for thermophoretic mobility driven by near-surface phase transition is …

Moving Obstacle Detection And Avoidance For Unmanned Ground Vehicle, Gangadhar Rajashekaraiah

Mechanical and Aerospace Engineering Theses - Archive

This thesis presents the development and implementation of an autonomous obstacle avoidance algorithm for UGV (Unmanned Ground Vehicle). The research improves the prior work by enhancing the obstacle avoidance capability to handle moving obstacle as well as stationary obstacles. A mathematical representation of the area of operation with obstacles is formulated by PTEM (Probabilistic Threat Exposure Map). The PTEM quantifies the risk in being at a position in an area with different types of threat. Threat in this context means UGV getting close to or running into stationary and moving obstacles. A LRF (Laser Range Finder) sensor mounted on the …

Computational Flow Analysis Of A Flapping Micro-Flyer Wing For Cycle-Averaged Force Production, Nitesh Rajendra Rajput

Mechanical and Aerospace Engineering Theses - Archive

Human engineers have been trying long to mimic creations of nature for their own benefits. One such area of interest is the insect based micro flapping wing flyers for their wide employment in commercial as well as military applications. These micro air vehicles (MAVs) are capable of performing acts that can be too dangerous for humans to perform, such as tactical reconnaissance in a combat zone. The maneuverability required of these MAVs call for a careful design and thorough study of their aerodynamic performance. This research goal is to provide an estimation of the forces generated during the flapping motion …

Scaling Laws For Radial Foil Bearings, Srikanth Honavara Prasad

Mechanical and Aerospace Engineering Theses - Archive

The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort(time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings …

Precipitation, Orientation And Composition Effects On The Shape Memory Properties Of High Strength Nitihfpd Alloys, Emre Acar

Theses and Dissertations--Mechanical and Aerospace Engineering

NiTiHf high temperature shape memory alloys are attractive due to their high operating temperatures (>100 ^oC) and acceptable transformation strain compared to NiTi. However, NiTiHf has limitations due to their lack of ductility and low strength, resulting in poor shape memory properties. In this study, Pd has been added to NiTiHf alloys in an attempt to improve their shape memory behavior. A combined approach of quaternary alloying and precipitation strengthening was used.

The characterization of a Ni_45.3Ti_29.7Hf₂₀Pd₅ (at. %) polycrystalline alloy was performed in compression after selected aging treatments. Transmission electron …

A Design Pathfinder With Material Correlation Points For Inflatable Systems, Jared T. Fulcher

Theses and Dissertations--Mechanical and Aerospace Engineering

The incorporation of inflatable structures into aerospace systems can produce significant advantages in stowed volume to mechanical effectiveness and overall weight. Many applications of these ultra-lightweight systems are designed to precisely control internal or external surfaces, or both, to achieve desired performance. The modeling of these structures becomes complex due to the material nonlinearities inherent to the majority of construction materials used in inflatable structures. Furthermore, accurately modeling the response and behavior of the interfacing boundaries that are common to many inflatable systems will lead to better understanding of the entire class of structures. The research presented involved using nonlinear …

Filtered-Dynamic-Inversion Control For Fixed-Wing Unmanned Aerial Systems, Jon Mullen

Theses and Dissertations--Mechanical and Aerospace Engineering

Instrumented umanned aerial vehicles represent a new way of measuring turbulence in the atmospheric boundary layer. However, autonomous measurements require control methods with disturbance-rejection and altitude command-following capabilities. Filtered dynamic inversion is a control method with desirable disturbance-rejection and command-following properties, and this controller requires limited model information. We implement filtered dynamic inversion as the pitch controller in an altitude-hold autopilot. We design and numerically simulate the continuous-time and discrete-time filtered-dynamic-inversion controllers with anti-windup on a nonlinear aircraft model. Finally, we present results from a flight experiment comparing the filtered-dynamic-inversion controller to a classical proportional-integral controller. The experimental results show …

Multidimensional Modeling Of Pyrolysis Gas Transport Inside Orthotropic Charring Ablators, Haoyue Weng

Theses and Dissertations--Mechanical and Aerospace Engineering

During hypersonic atmospheric entry, spacecraft are exposed to enormous aerodynamic heat. To prevent the payload from overheating, charring ablative materials are favored to be applied as the heat shield at the exposing surface of the vehicle. Accurate modeling not only prevents mission failures, but also helps reduce cost. Existing models were mostly limited to one-dimensional and discrepancies were shown against measured experiments and flight-data. To help improve the models and analyze the charring ablation problems, a multidimensional material response module is developed, based on a finite volume method framework. The developed computer program is verified through a series of test-cases, …

Load Transfer In An Isolated Particle Embedded Within An Epoxy Matrix, Erik Durnberg

Electronic Theses and Dissertations

Particulate composites are widely used in many aerospace applications such as protective coatings, adhesives, or structural members of a body and their mechanical properties and behavior have gained increasing significance. The addition of modifiers such as alumina generally leads to improved mechanical properties. This addition also enables the non-invasive study of the load transfer between the particle and the matrix. Understanding the load transfer between the particulate and the matrix material is the first step to understanding the behavior and mechanical properties of the composite as a whole. In this work, samples with an isolated alumina particle embedded in an …

Ignition Studies Of Diisopropyl Ketone, A Second-Generation Biofuel, Owen Pryor

HIM 1990-2015

This thesis focuses on ignition of diisopropyl ketone (DIPK), a new biofuel candidate that is produced by endophytic conversion. The ignition delay times behind reflected shockwaves were modeled in a high-pressure shock tube. The ignition delay times were compared to other biofuels and gasoline surrogates. Parametric studies of the ignition delay experiments were performed between 1-10 atm and 900 -1200K. An OH optical sensor was developed in conjunction for the ignition delay experiments. The OH optical sensor uses a microwave discharge lamp to generate light at 308 nm that will then be shined through the combustion reaction. Using Beer-Lambert law …

Nondestructive Analysis Of Advanced Aerospace Materials Via Spectroscopy And Synchrotron Radiation, Albert Manero

Electronic Theses and Dissertations

Advanced aerospace materials require extensive testing and characterization to anticipate and ensure their integrity under hostile environments. Characterization methods utilizing synchrotron X-Ray diffraction and spectroscopy can decrease the time required to determine an emerging material's readiness for application through intrinsic information on the material response and failure mechanisms. In this study, thermal barrier coating samples applicable to turbine blades of jet engines were studied using Raman and Photoluminescence spectroscopy as well as Synchrotron X-ray diffraction while Kevlar based fiber composites applicable to ballistic resistant armor were studied using Raman spectroscopy to investigate the mechanical state and corresponding damage and failure …

Keeping The Skies Safe, Massood Towhidnejad, Andrew J. Kornecki

Department of Electrical Engineering and Computer Science - Daytona Beach

Professors Massood Towhidnejad and Andrew Kornecki shine a light on how their lab is helping government and the aviation industry to enhance the safety and security of software-intensive systems.