Aerospace Engineering Commons^™

On The Unusual Amber Coloration Of Nanoporous Sol-Gel Processed Al-Doped Silica Glass: An Experimental Study, Alvin Chang, Yujuan He, Maria A. Torres Arango, Maoyu Wang, Yang Ren, Zhenxing Feng, Chih-Hung Chang, Knostantinos A. Sierros

Faculty & Staff Scholarship

Silica is the most abundant component on the earth’s surface. It plays an important role in many natural processes. Silica is also a critical material for a wide range of technical applications such as in optics and electronics. In this work, we discuss our recent experimental observation of the unusual amber coloration of aluminum doped sol-gel glass that has not been reported in the past. We characterized Al-doped sol-gel glasses, prepared at different sintering temperature, using a plethora of techniques to investigate the origin of this unusual coloration and to understand their structural and chemical properties. We used these experimental …

Programmed Design Of A Lithium–Sulfur Battery Cathode By Integrating Functional Units, Zhipeng Zeng, Wei Li, Qiang Wang, Xingbo Liu

Faculty & Staff Scholarship

Sulfur is considered to be one of the most promising cathode materials due to its high theoretical specific capacity and low cost. However, the insulating nature of sulfur and notorious “shuttle effect” of lithium polysulfides (LiPSs) lead to severe loss of active sulfur, poor redox kinetics, and rapid capacity fade. Herein, a hierarchical electrode design is proposed to address these issues synchronously, which integrates multiple building blocks with specialized functions into an ensemble to construct a self‐supported versatile cathode for lithium–sulfur batteries. Nickel foam acts as a robust conductive scaffold. The heteroatom‐doped host carbon with desired lithiophilicity and electronic conductivity …

From Statistical Correlations To Stochasticity And Size Effects In Sub-Micron Crystal Plasticity, Hengxu Song, Stefanos Papanikolaou

Faculty & Staff Scholarship

Metals in small volumes display a strong dependence on initial conditions, which translates into size effects and stochastic mechanical responses. In the context of crystal plasticity, this amounts to the role of pre-existing dislocation configurations that may emerge due to prior processing. Here, we study a minimal but realistic model of uniaxial compression of sub-micron finite volumes. We show how the statistical correlations of pre-existing dislocation configurations may influence the mechanical response in multi-slip crystal plasticity, in connection to the finite volume size and the initial dislocation density. In addition, spatial dislocation correlations display evidence that plasticity is strongly influenced …

Gnss/Lidar-Based Navigation Of An Aerial Robot In Sparse Forests, Antonio C. Chiella, Henrique N. Machado, Bruno O.S. Teixeira, Guilherme A.S. Pereira

Faculty & Staff Scholarship

Autonomous navigation of unmanned vehicles in forests is a challenging task. In such environments, due to the canopies of the trees, information from Global Navigation Satellite Systems (GNSS) can be degraded or even unavailable. Also, because of the large number of obstacles, a previous detailed map of the environment is not practical. In this paper, we solve the complete navigation problem of an aerial robot in a sparse forest, where there is enough space for the flight and the GNSS signals can be sporadically detected. For localization, we propose a state estimator that merges information from GNSS, Attitude and Heading …

Scaling Analysis And Experimental Investigation Of A Rotating Detonation Engine, David Thomas Billups

Graduate Theses, Dissertations, and Problem Reports (ETD)

Pressure gain combustion (PGC) technologies, specifically rotating detonation engines (RDEs), are poised to provide the next big leap in gas turbine engine advancement, significantly increasing the thermal. RDEs make use of thermodynamic advantages of isochoric as opposed to isobaric combustion. Theorized to increase thermal efficiency by up to 7% [1], the RDE would have significant impact on reducing anthropogenic carbon emissions. In addition to efficiency gains, the RDE also provides mechanical simplicity and reduced size advantages compared to it’s traditional counterparts and PGC competition.

The United States (U.S.) Department of Energy (DOE) National Energy Technology Laboratory (NETL) maintains and operates …

Immunity-Based Framework For Autonomous Flight In Gps-Challenged Environment, Mohanad Al Nuaimi

Graduate Theses, Dissertations, and Problem Reports (ETD)

In this research, the artificial immune system (AIS) paradigm is used for the development of a conceptual framework for autonomous flight when vehicle position and velocity are not available from direct sources such as the global navigation satellite systems or external landmarks and systems. The AIS is expected to provide corrections of velocity and position estimations that are only based on the outputs of onboard inertial measurement units (IMU). The AIS comprises sets of artificial memory cells that simulate the function of memory T- and B-cells in the biological immune system of vertebrates. The innate immune system uses information about …

Conceptual Design Of Male Uavs, Vincent Spada

Graduate Theses, Dissertations, and Problem Reports (ETD)

The conceptual design process of aircraft involves the creation of a product, in this case UAVS (unmanned aerial vehicles), using the most effective means possible across multiple subdisciplines of Aerospace Engineering. This paper will outline a unique methodology that involves calculating certain design variables such as wing loading, power loading, aspect ratio and cruise altitude in the conceptual design phase for MALE (medium altitude long endurance) UAVs. Aircraft characteristics from MALE UAVs such as the MQ-9 predator and MQ-1 reaper will used for a comparative aircraft study as “jumping off” points in order to carry out the initial calculations. An …

Artificial Immune System For Unmanned Aerial Vehicle Abnormal Condition Detection And Identification, Ryan G. Mclaughlin

Graduate Theses, Dissertations, and Problem Reports (ETD)

A detection and identification scheme for abnormal conditions was developed for an unmanned aerial vehicle (UAV) based on the artificial immune system (AIS) paradigm. This technique involves establishing a body of data to represent normal conditions referred to as “self” and differentiating these conditions from abnormal conditions, referred to as “non-self”. Data collected from simulation of the UAV attempting to autonomously fly a pre-decided trajectory were used to develop and test a scheme that was able to detect and identify aircraft sensor and actuator faults. These faults included aerodynamic control surface locks and damages and angular rate sensor biases. The …

Enabling Robust State Estimation Through Covariance Adaptation, Ryan Magnum Watson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Several robust state estimation frameworks have been proposed over the previous decades. Underpinning all of these robust frameworks is one dubious assumption. Specifically, the assumption that an accurate a priori measurement uncertainty model can be provided. As systems become more autonomous, this assumption becomes less valid (i.e., as systems start operating in novel environments, there is no guarantee that the assumed a priori measurement uncertainty model characterizes the sensors current observation uncertainty).

In an attempt to relax this assumption, a novel robust state estimation framework is proposed. The proposed framework enables robust state estimation through the iterative adaptation of the …

Utilization Of Scale In Keypoint Detection And Feature Description, Andrew P. Rhodes

Graduate Theses, Dissertations, and Problem Reports (ETD)

Ubiquitous availability of inexpensive three dimensional (3D) sensors has led to an abundance of keypoint detection and feature description techniques for point-clouds. While some recent methods utilize color along with geometric information, most only implicitly discuss -- if not completely disregard -- the information provided by scale. Scale is an inherent characteristic of any keypoint or feature that describes its physical size or region of support.

Exploiting information provided by scale facilitates the processes of keypoint detection and feature description. A 3D scale-space, extended from robust and popular 2D methods, is constructed to diffuse a signal on triangulated meshes. Methods …

Improving Solder Joints Formed In Microgravity By Use Of Magnetic Soldering Paste Additives, Aaron Dunkle

Graduate Theses, Dissertations, and Problem Reports (ETD)

With the expansion of the space industry, the need for the capability to repair electronics in space grows. Previous researchers have found that soldering in microgravity has yielded joints of poorer quality than those made on Earth, with increased interior porosity. WVU’s microgravity research team (MRT) constructed an experiment to solder onboard a microgravity aircraft to explore this problem and to test a possible solution. MRT’s experiment collected solder samples both in microgravity and a ground test, which were then cross-sectioned to allow the interior porosity of the joints to be studied. This determined that there was an increase in …

Analytical Cpg Model Driven By Limb Velocity Input Generates Accurate Temporal Locomotor Dynamics, Sergiy Yakovenko, Anton Sobinov, Valeriya Gritsenko

Faculty & Staff Scholarship

The ability of vertebrates to generate rhythm within their spinal neural networks is essential for walking, running, and other rhythmic behaviors. The central pattern generator (CPG) network responsible for these behaviors is well-characterized with experimental and theoretical studies, and it can be formulated as a nonlinear dynam- ical system. The underlying mechanism responsible for locomotor behavior can be expressed as the process of leaky integration with resetting states generating appropriate phases for changing body velocity. The low-dimensional input to the CPG model generates the bilateral pattern of swing and stance modulation for each limb and is consistent with the desired …

Fabrication And Thermoelectric Characterization Of Transition Metal Silicide-Based Composite Thermocouples, Gunes A. Yakaboylu, Rajalekshmi C. Pillai, Katarzyna Sabolsky, Edward M. Sabolsky

Faculty & Staff Scholarship

Metal silicide-based thermocouples were fabricated by screen printing thick films of the powder compositions onto alumina tapes followed by lamination and sintering processes. The legs of the embedded thermocouples were composed of composite compositions consisting of MoSi2, WSi2, ZrSi2, or TaSi2 with an additional 10 vol % Al2O3 to form a silicide–oxide composite. The structural and high-temperature thermoelectric properties of the composite thermocouples were examined using X-ray diffraction, scanning electron microscopy and a typical hot–cold junction measurement technique. MoSi2-Al2O3 and WSi2-Al2O3 composites exhibited higher intrinsic Seebeck coefficients (22.2–30.0 μV/K) at high-temperature gradients, which were calculated from the thermoelectric data of …

Interval Fuzzy Model For Robust Aircraft Imu Sensors Fault Detection, Michele Crispoltoni, Mario Luca Fravolini, Fabio Balzano, Stephane D'Urso, Marcello Rosario Napolitano

Faculty & Staff Scholarship

This paper proposes a data-based approach for a robust fault detection (FD) of the inertial measurement unit (IMU) sensors of an aircraft. Fuzzy interval models (FIMs) have been introduced for coping with the significant modeling uncertainties caused by poorly modeled aerodynamics. The proposed FIMs are used to compute robust prediction intervals for the measurements provided by the IMU sensors. Specifically, a nonlinear neural network (NN) model is used as central prediction of the sensor response while the uncertainty around the central estimation is captured by the FIM model. The uncertainty has been also modelled using a conventional linear Interval Model …

Insights Into The Magnetic Dead Layer In La0.7sr0.3mno3 Thin Films From Temperature, Magnetic Field And Thickness Dependence Of Their Magnetization, N. Mottaghi, M.S. Seehra, R. Trappen, S. Kumari, Chih-Yeh Huang, S. Yousefi, G.B. Cabrera, A.H. Romero, M.B. Holcomb

Faculty & Staff Scholarship

Experimental investigations of the magnetic dead layer in 7.6 nm thick film of La0.7Sr0.3MnO3 (LSMO) are reported. The dc magnetization (M) measurements for a sample cooled to T = 5 K in applied field H = 0 reveal the presence of negative remanent magnetization (NRM) in the M vs. H (magnetic field) measurements as well as in the M vs. T measurements in H = 50 Oe and 100 Oe. The M vs. T data in ZFC (zero-field-cooled) and FC (field-cooled) protocols are used to determine the blocking temperature TB in different H. Isothermal hysteresis loops at differ- ent T …

Parametric Investigation Of Combustion And Heat Transfer Characteristics Of Oscillating Linear Engine Alternator, Mehar Bade, Nigel N. Clark, Matthew C. Robinson, Parviz Famouri

Faculty & Staff Scholarship

An Oscillating Linear Engine Alternator (OLEA) has the potential to overcome the thermal, mechanical, and combustion inadequacies encountered by the conventional slider-crank engines. The linear engines convert the reciprocating piston motion into electricity, thereby eliminating needless crankshaft linkages and rotational motion. As the dead center positions are not explicitly identified unlike crankshaft engines, the linear engine exhibits different stroke and compression ratio every cycle and should manage the unfavorable events like misfire, rapid load changes, and overfueling without the energy storage of a flywheel. Further, the apparatus control and management strategy is difficult for OLEA when compared to conventional engines …

Study Of Material Compatibility For A Thermal Energy Storage System With Phase Change Material, Songgang Qiu, Laura Solomon, Ming Fang

Faculty & Staff Scholarship

The suitability of stainless steel 316L and Inconel 625 for use in a latent heat thermal energy storage (TES) system was investigated. A NaCl–NaF eutectic mixture with a melting temperature of 680 ◦C was used as the phase change material (PCM). Containers were filled with the PCM prior to heating to 750 ◦C, then examined after 100 and 2500 h of high-temperature exposure by analyzing the material surface and cross-section areas. A small amount of corrosion was present in both samples after 100 h. Neither sample suffered significant damage after 2500 h. The undesirable inter-granular grain boundary attack found in …

Air Data Sensor Fault Detection With An Augmented Floating Limiter, Fabio Balzano, Mario Luca Fravolini, Marcello R. Napolitano, Stephane D'Urso, Michele Crispoltoni, Giuseppe Del Core

Faculty & Staff Scholarship

Although very uncommon, the sequential failures of all aircraft Pitot tubes, with the consequent loss of signals for all the dynamic parameters from the Air Data System, have been found to be the cause of a number of catastrophic accidents in aviation history. This paper proposes a robust data-driven method to detect faulty measurements of aircraft airspeed, angle of attack, and angle of sideslip. This approach first consists in the appropriate selection of suitable sets of model regressors to be used as inputs of neural network-based estimators to be used online for failure detection. The setup of the proposed fault …

Learning Local, Quenched Disorder In Plasticity And Other Crackling Noise Phenomena, Stefanos Papanikolaou

Faculty & Staff Scholarship

When far from equilibrium, many-body systems display behavior that strongly depends on the initial conditions. A characteristic such example is the phenomenon of plasticity of crystalline and amorphous materials that strongly depends on the material history. In plasticity modeling, the history is captured by a quenched, local and disordered flow stress distribution. While it is this disorder that causes avalanches that are commonly observed during nanoscale plastic deformation, the functional form and scaling properties have remained elusive. In this paper, a generic formalism is developed for deriving local disorder distributions from field- response (e.g., stress/strain) timeseries in models of crackling …

Performance Trades For Multiantenna Gnss Multisensor Attitude Determination Systems, Nathan A. Tehrani, Jason N. Gross

Faculty & Staff Scholarship

We present various performance trades for multiantenna global navigation satellite system (GNSS) multisensor attitude estimation systems. In particular, attitude estimation performance sensitivity to various error sources and system configurations is assessed. This study is motivated by the need for system designers, scientists, and engineers of airborne astronomical and remote sensing platforms to better determine which system configuration is most suitable for their specific application. In order to assess performance trade-offs, the attitude estimation performance of various approaches is tested using a simulation that is based on a stratospheric balloon platform. For GNSS errors, attention is focused on multipath, receiver measurement …

Electrostatic Potential And Valence Modulation In La0.7sr0.3mno3 Thin Films, Robbyn Trappen, A. C. Garcia- Castro, Vu Thanh Tra, Chih-Yeh Huang, Wilfredo Ibarra-Hernandez, James Fitch, Sobhit Singh, Jingling Zhou, Guerau Cabrera, Ying-Hao Chu, James M. Lebeau, Aldo H. Romero, Mikel B. Holcomb

Faculty & Staff Scholarship

The Mn valence in thin film La0.7Sr0.3MnO3 was studied as a function of film thickness in the range of 1–16 unit cells with a combination of non-destructive bulk and surface sensitive X-ray absorption spectroscopy techniques. Using a layer-by-layer valence model, it was found that while the bulk averaged valence hovers around its expected value of 3.3, a significant deviation occurs within several unit cells of the surface and interface. These results were supported by first principles calculations. The surface valence increases to up to Mn3.7+, whereas the interface valence reduces down to Mn2.5+. The change in valence from the expected …

Study Of Biomimetic Micro And Macro Structures For Drag Reduction, Justin S. Schrout

Graduate Theses, Dissertations, and Problem Reports (ETD)

The ever increasing demand for global travel coupled with increasing costs of fuels have prompted many researchers to study new methods to save fuel to make travel more efficient. One of the proverbial low-hanging fruits for fuel efficiency is aerodynamic drag reduction. Simple changes in the shape or placement of structures on the surface of different types of vehicles have been shown to increase fuel efficiency by reducing drag (e.g., add-on lower and aft wake fairings on tractor trailers which have seen a tremendous rise in popularity on US highways in recent years). Areas of interest in drag reduction have …

Instrumentation And Inertial Navigation Systems Design For Tensegrity Robot Implementations, Scott Edward Harper

Graduate Theses, Dissertations, and Problem Reports (ETD)

One of the major challenges faced when developing missions for the exploration of planetary bodies is the risk these terrains pose on the science platform when using a traditional lander or wheeled rover. One means of developing platforms to traverse these harsh terrains is to utilize mobility systems comprised of tensegrity structures. These structures have the capacity to distribute loads across a network of axially loaded members such that they can be constructed in a very lightweight manner and morph their geometries when required. In literature, there has been significant progress in simulated environments to utilize tensegrity structures as mobility …

Design And Evaluation Of Novel Attitude Estimation System Using Mems Sensors For Indoor Uas, Joshua Bruce Milam

Graduate Theses, Dissertations, and Problem Reports (ETD)

Most small unmanned aerial systems in use today, employ extended Kalman filter sensor fusion algorithms in order to provide accurate estimations of attitude or orientation. These complex algorithms use measurements from GPS receivers and magnetometer sensors that can be rendered useless in GPS denied environments or areas of significant magnetic interference, such as inside buildings or other structures. The complexity of these algorithms makes them inaccessible for some researchers and hobbyists who wish to code their own attitude estimation algorithms. This complexity is also computationally expensive and requires processors that are powerful enough to operate the algorithms along with any …

Thermal-Fatigue And Thermo-Mechanical Equivalence For Transverse Cracking Evolution In Laminated Composites, Javier Cabrera Barbero

Graduate Theses, Dissertations, and Problem Reports (ETD)

Carbon fiber reinforced plastics (CFRP) are potential materials for many aerospace and aeronautical applications due to their high specif strength/weight and a low coeffcient of thermal expansion (CTE) resulting in a high long-term stability. Among candidate structures, the re-entry reusable launch vehicles (RLV), the fuel oxidant storage and transportation at cryogenic temperature, space satellites, and aircraft structure (frame, wings, etc...) can be highlighted. However, CFRP are prone to internal damage as a result of high residual stresses and thermal fatigue loading. In this study, micro-cracking damage evolution in laminated composites subjected to monotonic cooling and thermal cyclic loads is developed …

Space Race - Introduction, Jesse Lackey

Cold War & Space Race

The infographic linked below is a timeline of events in 20^th-century America related to the Cold War, the Space Race, and the Civil Rights Movement. The timeline is designed to put the events in Hidden Figures into historical context. The timeline chronologically compares groundbreaking historical events such as the Civil Rights Act of 1964 and the creation of NASA alongside the historical presence of the three women, Dorothy Vaughan, Katherine Johnson, and Mary Jackson, that the reading is focused around. The book hops around from year to year and is very difficult to follow chronologically. That is part …

Influential Women In Flight - Trading Cards, Becca Stegmann

Women in STEM

For this assignment, I created a collection of trading cards that provide biographies and important information about influential minority women in flight. The front of each card has basic demographic information, including each person’s name, birth date, hometown, and what they are known for. The back of each card has a slightly longer explanation of each person, followed by something they are quoted with saying and some key facts about their lives. The cards can be printed out in color and laminated for longevity if desired.

Women In Engineering, Arianna Frisina

Women in STEM

The timeline consists of significant events of women in engineering. The years range from 1939 to 1974 and contains information from Hidden Figures and a peer-reviewed article that was found on JSTOR. The timeline shows the years that the women (Katherine Johnson, Dorothy Vaughan, Christine Darden, and Mary Jackson) began working for NACA. It also includes the time Christine Darden discovered her passion for math, when Kitty O’Brien Joyner sued the University of Virginia, the year of the Civil Rights Act, when Katherine Johnson was able to attend the editorial meetings, and Mary Jackson enrolling in engineering classes. The year …

Influential Women In Flight - Introduction, Becca Stegmann

Women in STEM

For this assignment, I created a collection of trading cards that provide biographies and important information about influential minority women in flight. The front of each card has basic demographic information, including each person’s name, birth date, hometown, and what they are known for. The back of each card has a slightly longer explanation of each person, followed by something they are quoted with saying and some key facts about their lives. The cards can be printed out in color and laminated for longevity if desired.

Timeline - Space Race, Jesse Lackey

Cold War & Space Race

The infographic attached along with this note is a timeline of several historical events that took place primarily in the 20th century. This timeline will serve as a useful piece in the classroom when one is teaching the reading, Hidden Figures, and looking to pinpoint it and the events related to it within a historical context. The timeline chronologically compares groundbreaking historical events such as the Civil Rights Act of 1964 and the creation of NASA alongside the historical presence of the three women, Dorothy Vaughan, Katherine Johnson, and Mary Jackson, that the reading is focused around.