Digital Commons Network^™

Linear Burn Rate Of Monopropellant For Multi-Mode Micropropulsion, Alex J. Mundahl, Steven P. Berg, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-mode micro propulsion is a technology that can enable rapidly composable small satellites with unprecedented mission flexibility. To maximize mission flexibility a multi-mode micro propulsion monopropellant must be shared between the chemical and electric propulsion modes. Previous research has identified a promising monopropellant that is both readily catalytically exothermically decomposed (chemical mode) and electro sprayable (electric mode). In this work the linear burn rate of this monopropellant is determined and used to aid the design of a microtube catalytic chemical thruster. Experiments with a pressurized fixed volume reactor are used to determine the linear burn rate. Benchmark experiments use a …

Applying Convolutional Neural Networks For The Source Reconstruction, He Ming Yao, Wei E.I. Sha, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a novel source reconstruction method (SRM) based on the convolutional neural network algorithm. The conventional SRM method usually requires the scattered field data oversampled compared to that of target object grids. To achieve higher accuracy, the conventional SRM numerical system is highly singular. To overcome these difficulties, we model the equivalent source reconstruction process using the machine learning. The equivalent sources of the target are constructed by a convolutional neural networks (ConvNets). It allows us to employ less scattered field samples or radar cross section (RCS) data. And the ill-conditioned numerical system is effectively avoided. Numerical examples …

The Rollamo 2018, Missouri University Of Science And Technology

Yearbooks

No abstract provided.

Machine Learning Based Multilevel Fast Multipole Algorithm, Jia Jing Sun, Sheng Sun, Yongpin Chen, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel translator calculation method for the multilevel fast multipole algorithm (MLFMA) is proposed based on a machine learning approach. The generalized regression neural networks are introduced to fit the translation function of MLFMA during the procedure of eletromagnetic scattering analysis. Compared to the traditional method, the new method inherits advantages of the generalized regression neural networks (GRNN) and can approximate the translator with high accuracy simultaneously. As an example, a two-level 2D MLFMA for a perfect electrically conductor (PEC) is finally implemented and the translators are reconstructed by using the proposed model. The numerical results validate …

Machine Learning Based Neural Network Solving Methods For The Fdtd Method, He Ming Yao, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, two novel computational processes are proposed to solve Finite-Difference Time-Domain (FDTD) based on machine learning deep neural networks. The field and boundary conditions are employed to establish recurrent neural network FDTD (RNN-FDTD) model and convolution neural network FDTD (CNN-FDTD) model respectively. Numerical examples from scalar wave equations are provided to benchmark the performance of the proposed methods. The results demonstrate that the newly proposed methods could solve FDTD steps with satisfactory accuracy. According to our knowledge, these are unreported new approaches for machine learning based FDTD solving methods.

Behavior Of Eb Frp Masonry Bond Under Service Temperature, Zuhair Al-Aljaberi, John J. Myers, K. Chandrashekhara

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The interest in advanced composites in repairing and strengthening infrastructure systems has considerably increased, especially as the application externally bonded (EB) fiber reinforced polymer (FRP) has become more well established. Previous research on bond behavior has focused on impact of durability by considering exposure to harsh environmental conditions and testing the specimens after exposure, rather than testing bond performance during exposure. The influence of directly applying temperature on bond behavior represents an open topic that needs to be investigated in more detail. This study is one of the first studies to investigate the bond behavior when the composite is subjected …

Containment Control Of Heterogeneous Systems With Non-Autonomous Leaders: A Distributed Optimal Model Reference Approach, Yongliang Yang, Shusen Cheng, Yixin Yin, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a distributed optimal model reference adaptive control approach for solving containment control of heterogeneous multi-agent systems (MASs) with non-autonomous leaders. First, a fully distributed adaptive observer is designed to provide for each agent the desired reference trajectory by estimating the convex hull spanned by leaders. The distributed observer dynamics serves as a reference model for each follower to synchronize. The global communication graph information or the leader dynamics is not required to design the observer. In contrast to existing model reference adaptive controllers (MRAC) for single-agent systems and containment control solutions for MASs, the proposed MRAC approach …

Investigation Of High Indium-Composition Ingan/Gan Heterostructures On Zno Grown By Metallic Organic Chemical Vapor Deposition, M. Tian, Y. D. Qian, C. Zhang, L. Li, S. D. Yao, I. T. Ferguson, D. N. Talwar, J. Y. Zhai, D. H. Meng, K. Y. He, L. Y. Wan, Z. C. Feng

Electrical and Computer Engineering Faculty Research & Creative Works

The optical properties and film quality for a series of high-In composition InGaN films grown on ZnO substrate by metal-organic chemical vapor deposition (MOCVD) are characterized by using high resolution X-ray diffraction (HRXRD), Rutherford backscattering (RBS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and Raman scattering spectroscopy (RSS). The In composition is evaluated by analyzing the RBS and PL emission spectra. The XPS measurements revealed the diffusion of Zn atoms from the substrate into InGaN films. All the analyses of experimental measurements have shown that the growth temperature played an important role in indium composition as well as of film quality. …

Application Of Improved Fast Dynamic Allan Variance For The Characterization Of Mems Gyroscope On Uav, Qian Zhang, Xueyun Wang, Shiqian Wang, Chaoying Pei

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microelectromechanical systems (MEMS) are core components in unmanned aerial vehicles (UAV). The precision of MEMS sensors is very important when the GPS signal is invalid. However, the precision and performance of MEMS sensors will be degraded by the changing of environment. Therefore, estimation and identification of the various noise terms existing in MEMS sensors are deemed to be necessary. The Allan variance is a common and standard method to analyze MEMS sensors, but it cannot be used to analyze the dynamic characteristics. The dynamic Allan variance (DAVAR) is a sliding version of the Allan variance. It is a practical tool …

Efficient Inverse Design Of Transonic Airfoils Using Variable-Resolution Models And Manifold Mapping, Xiaosong Du, Leifur Leifsson, Slawomir Koziel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents an efficient approach for simulation-based inverse design of airfoil shapes using variable-fidelity computational fluid dynamics models and manifold mapping (MM). Inverse design involves determining an airfoil shape fulfilling a given target performance characteristic. In particular, the pressure coefficient distribution is typically used in aerodynamic inverse design. Such a task can be challenging when using computationally expensive simulations. In the context of local optimization, the MM technique searches for a new design in the vicinity of the current design by constructing a fast multi-fidelity model, which is setup by the available evaluations of each of the high- and …

Outsmart Moore’S Law With Machine Learning, Dustin Tanksley, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Over the last half century, computing has transformed most aspects of society due to a rapid increase in computation power. With the possible end of Moore’s Law in sight, much of this growth could come to an end. This paper will discuss why machine learning will continue growing even after Moore’s Law, and demonstrate why it is a great time to enter the field.

First Search For Nontensorial Gravitational Waves From Known Pulsars, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper …

A Two-Dimensional Simulation Of Grain Structure Growth Within Substrate And Fusion Zone During Direct Metal Deposition, Jingwei Zhang, Lei Yan, Wei Li, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this chapter, a predictive multiscale model based on a cellular automaton (CA)-finite element (FE) method has been developed to simulate thermal history and microstructure evolution during metal solidification for direct metal deposition (DMD) process. The macroscopic FE calculation that is validated by the thermocouple experiment is developed to simulate the transient temperature field and cooling rate of single layer and multiple layers. In order to integrate the different scales, a CA-FE coupled model is developed to combine with thermal history and simulate grain growth. In the mesoscopic CA model, heterogeneous nucleation sites, grain growth orientation and rate, epitaxial growth, …

Green Function Of The Poisson Equation: D = 2, 3, 4, Ulrich D. Jentschura, J. Sapirstein

Physics Faculty Research & Creative Works

We study the Green function of the Poisson equation in two, three and four dimensions. The solution g of the equation ∇→2 g(x→ - x→') = δ(D) (x→ - x→') where x→ and x→' are D-dimensional position vectors, is customarily expanded into radial and angular coordinates. For the two-dimensional case (D = 2), we find a subtle interplay of the necessarily introduced scale L with the radial component of zero magnetic quantum number. For D = 3, the well-known expressions are briefly recalled; this is done in order to highlight the analogy with the four-dimensional case, where we uncover analogies …

Effect Of Thickness On The Structure And Corrosion Performance Of Sputtered Ce-Al-O Coatings On Al 2024-T3 Alloy Substrates, Yuanyuan Liu, Jiamu Huang, Lilu Qin, James B. Claypool, Matthew J. O'Keefe, Yiming Jiang

Materials Science and Engineering Faculty Research & Creative Works

Ce-Al-O coatings with thicknesses between ca. 136 nm and 1094 nm were deposited on Al 2024-T3 alloy substrates using magnetron co-sputtering of independent Al and CeO2 targets. The Ce-Al-O coatings with thicknesses from ca. 136 nm to 490 nm were compact, dense, and did not have distinct X-ray diffraction peaks. The ca. 1094 nm thick Ce-Al-O coating exhibited a columnar-textured outer layer ∼700 nm thick and a dense, ∼390 nm thick inner layer. X-ray photoelectron spectroscopy analysis revealed that the Ce-Al-O coatings contained Ce (III) species, and that the Al/Ce atomic ratio decreased with increasing coating thickness. Electrochemical corrosion data …

Femtosecond Laser-Matter Interactions In Ternary Zinc Phosphate Glasses, J. Hernandez-Rueda, N. W. Troy, P. Freudenberger, Richard K. Brow, D. M. Krol

Materials Science and Engineering Faculty Research & Creative Works

We investigate the interaction of ultrashort laser pulses with ternary zinc phosphate glasses. We explore the viability of ten different glass compositions with different levels of alumina to inscribe optical waveguides via the fs-laser direct writing technique, finding that only samples with [O]/[P] ratios of 3.25 are suitable candidates. We also test a zinc magnesium phosphate glass to fabricate waveguide Bragg gratings in order to generate filters and mirrors with specific spectral properties. Confocal Raman spectroscopy inspection shows that laser-damaged material exhibits a relative intensity decrease and a subtle blue-shift on the 1209 cm-1 Raman peak, which implies a relative …

A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part I: Model Derivation, David W. Mead, Saman Monjezi, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new polydisperse "toy" constitutive model is derived and developed from fundamental principles and ideas governing the nonlinear rheology of linear flexible polymers [Mead et al., J. Rheol. 59, 335-363 (2015)]. Specifically, the new model is comprised of four fundamental pieces. First, the model contains a simple differential description of the entanglement dynamics of discrete entanglement pairs. Second, the model contains a differential description of the ij entanglement pair orientation tensor dynamics. Third, following a similar development by Mead and Mishler [J. Non-Newtonian Fluid Mech. 197, 61-79 and 80-90 (2013).], a diluted stretch tube is constructed to describe the relative …

A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part Ii. Modeling "Shear Modification" Following Cessation Of Fast Shear Flows, David W. Mead, Saman Monjezi, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

The polydisperse Mead-Park (MP) "toy" molecular constitutive model developed in Paper I [Mead et al., J. Rheol. 62, 121-134 (2017)] as well as our previously published work [e.g., J. Rheol. 59, 335-363 (2015)] is used in the "forward" direction to study model polydisperse melts of entangled linear flexible polymers in severe, fast shear flows. The properties of our new model are elucidated by way of numerical simulation of a representative model polydisperse polymer melt in step shear rate and interrupted shear flow. In particular, we demonstrate how the MP model simulates the individual molecular weight distribution (MWD) component dynamics as …

Multi-Objective Optimal Battery Placement In Distribution Networks, Kiana Khalilnejad

Masters Theses

"Due to high penetration of renewable energy resources in today's electricity generation, considerable voltage fluctuations are witnessed in power systems. As an attempt to solve this issue, in this study, multi-objective optimal placement and sizing of distribution-level battery storage system is performed using semidefinite programing. Placement of one or multiple battery system is studied under various objectives including the cost, voltage regulation, reactive power dispatch, renewable resource curtailment, and minimum network power losses. Power flow equations are solved in the form of semidefinite constraints and the rank constraint is ignored. Additionally, combination of these objectives to form a multi-objective problem …

Analyzing Sensor Based Human Activity Data Using Time Series Segmentation To Determine Sleep Duration, Yogesh Deepak Lad

Masters Theses

"Sleep is the most important thing to rest our brain and body. A lack of sleep has adverse effects on overall personal health and may lead to a variety of health disorders. According to Data from the Center for disease control and prevention in the United States of America, there is a formidable increase in the number of people suffering from sleep disorders like insomnia, sleep apnea, hypersomnia and many more. Sleep disorders can be avoided by assessing an individual's activity over a period of time to determine the sleep pattern and duration. The sleep pattern and duration can be …

Ferrite Assisted Geometry-Conformal Magnetic Induction Antenna And Subsea Communications For Auvs, Debing Wei, Li Yan, Xuanheng Li, Jie Wang, Jiefu Chen, Miao Pan, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

This paper designs a novel geometry-conformal antenna for Magnetic Induction (MI)-based subsea wireless communications for autonomous underwater vehicles (AUV). The designed tri-directional antennas can be wrapped directly on the surface of AUVs, such that the AUVs fluid dynamics are well maintained to ensure power efficiency of the vehicles. In addition, ferrite materials are added between the MI antenna and the metallic body surface of the AUVs to overcome the shielding effect and enhance the MI signal strength. The designed MI communication system is implemented in hardware and the effectiveness of the geometry-conformal MI antenna is demonstrated through COMSOL simulations and …

Advanced Ion Management To Improve Oil Recovery In Oil-Wet Carbonate-Sandstone Composite Reservoirs, Ali K. Alhuraishawy, Baojun Bai, Mingzhen Wei, Waleed H. Al-Bazzaz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Waterflooding with different ionic composition called advanced ion management which play a role with ionic composition of injected water to enhance the oil production. In the last decade, many studies pointed out that the composition of injected water could changes rock wettability during waterflooding. The main purpose of this study is to evaluate the effects of SO4 and low salinity water on improving oil recovery in oil-wet carbonate reservoirs. Sulfate ion concentration, low salinity water, rock composition, porosity, and permeability were examined using a designed model. Typical seawater, increase SO₄, two and three times in the seawater, and …

Carbon Black Production, Analyzing And Characterization, Shadha Khalid Jebur

Masters Theses

"Carbon black (CB) plays a significant function in the development of the electrical and mechanical properties of high performance for a tough elastic polymeric substance such as rubber materials. Thus, CB is widely used to manufacture a massive number of products such as reinforcing and pigment phase in automobile tires due to its high ability to increase tire life by reducing the thermal damage. This material is also used in belts, hoses, and other non-tire rubber goods. Before use in valuable materials. CB should first be analyzed and characterized by different instruments to obtain its mechanical properties. A new thermal …

Advanced Process To Embed Optical Fiber Sensors Into Casting Mold For Smart Manufacturing, Raghavender Reddy Jakka

Masters Theses

"Optical fiber sensors embedded in metals with distributed sensing can sense temperature at multiple points with single fiber. This is useful for smart manufacturing like structural health monitoring in aerospace industry and smart molds in manufacturing plants. There is a huge difference in thermal coefficient of expansion for fiber and metal. This is the reason for the increase in sensitivity for embedded fiber sensors. However, at high temperatures, the stress on the fiber increases, eventually damaging the sensor. The fiber-metal interface determines the sensor performance. A tight interface results in high sensitivity and a gap in the interface enhances sensing …

Bifunctional Porous Polymeric Fiber As A Catalyst For N-Phenylglycine Synthesis And Carbonation Of Propylene Oxide To Propylene Carbonate, Ahmed Abdulghani Almuslem

Masters Theses

"In this study, development of a polymeric bi-functional porous catalyst that can be used in various applications such as batch, packed-bed, and continuous flow reactors and the formation of highly important chemicals that have many applications in the industry. With this material many homogenous reactions can be conducted in heterogeneous environment which is more efficient and profitable. The catalyst was formed by grafting hollow fiber with APS then immobilized with Br using 1,2-dibromoprobane (Br/APS/PAI-HFs). The formed catalyst was tested with BET and FTIR to confirm the immobilization of Br. A porous polymeric material Br/APS/PAI-HFs provides the ability for ring opining …

Fluid Flow In A Krogh Cylinder: A Model For A Single Capillary And Surrounding Tissue, Xianjie Qiu

Masters Theses

"A model describing the flow of plasma from the capillaries to the interstitial space in the extravascular tissue and back into the capillaries is constructed and solved. The flow through the tissue or the interstitial spaces is described by the Brinkman equation for porous medium, modified to account for the presence of cells considered as spheres. The flow of blood through the capillaries is considered to be that of a Newtonian fluid. The flow between capillary and tissue is coupled by the permeability of the capillary wall. The nature of flow and its magnitude was found to be highly dependent …

An Investigation Of The Economic Order Quantity Model With Quantity Discounts Under An Environmental Objective, Tiffanie Marie Toles

Masters Theses

"In a sustainable supply chain, retailers are the direct link between customers and products. Retailers play an important role by relaying feedback such as customer satisfaction, inventory improvement, or product improvement to the other key players in a supply chain. Their overall goal is to reduce supply chain costs, such as the cost of ordering product, transporting product, or holding product in inventory. Other costs associated in a supply chain can include environmental and operations costs. It is important to consider these costs due to the impact environmental operations play in the role of how sustainable a supply chain can …

Characterization Of Free-Radical Solution Polymerizations Of Acrylamide Initiated By Persulfate Initiator Systems, Yashu Chen

Masters Theses

”In order to reduce the water production and improve the oil recovery of mature reservoir, various conformance control technologies have been extensively developed. Preformed particle gel (PPG), a cost-effective plugging agent, has been successfully applied to block the high permeability zone and thus to displace the water to up-swept zone.

A common PPG based on polyacrylamide hydrogel have been wildly used. Identifying the parameters that affect gelation performance and understand how these parameters affect the performance is very useful to predict and manipulate the gelation time and to control the performance of gels.

The objective of this research is to …

Universal Wavefront Transmission Through Disordered Media, Jayson Robert Summers

Masters Theses

”When electromagnetic waves propagate through random dielectric media, they scatter in a predictable, deterministic way. The process is also fully reversible. If one sends an exiting wave backward through the same material, it will converge back to its original form and location in the same amount of time it took to originally propagate through the material. Due to this predictability, a great deal of research has went into studying these scattering processes in multimode fibers, diffusers, biological tissues, and other media. Scientists have turned random scattering material into focusing lenses, image transmitters, and highly transmitting media by controlling the impinging …

Reprocessing Of The 2 Hz P-P Data From The Blackfoot 3c-2d Survey With Special Reference To Multicomponent Seismic Processing, Onur Akturk

Masters Theses

"The 3C-2D multicomponent seismic survey was acquired in the Blackfoot Field, which is located 15 km southeast of Strathmore, Alberta. The 2 Hz vertical component data were reprocessed to better image the target reservoir, the Glauconitic sand formation at approximately 1150 ms. The zone of the major reflector at about 1550 ms was also taken into consideration to determine the better seismic section for further processing. The main characteristics of the converted wave processing, such as common conversion point (CCP), asymptotic binning, gamma ratios, receiver statics, rotation of the data, positive/negative offsets, and anisotropy, were also summarized in this study. …