Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Aerospace Engineering (855)
- Manufacturing (333)
- Materials Science and Engineering (186)
- Electrical and Computer Engineering (108)
- Physical Sciences and Mathematics (105)
-
- Chemical Engineering (80)
- Mining Engineering (55)
- Ceramic Materials (51)
- Metallurgy (51)
- Civil and Environmental Engineering (49)
- Nuclear Engineering (46)
- Computer Sciences (45)
- Petroleum Engineering (44)
- Chemistry (29)
- Operations Research, Systems Engineering and Industrial Engineering (29)
- Engineering Mechanics (27)
- Engineering Science and Materials (27)
- Physics (24)
- Architectural Engineering (19)
- Architecture (19)
- Social and Behavioral Sciences (19)
- Applied Mechanics (17)
- Structural Materials (16)
- Mechanics of Materials (15)
- Biology (13)
- Life Sciences (13)
- Energy Policy (12)
- Public Affairs, Public Policy and Public Administration (12)
- Keyword
-
- Additive manufacturing (69)
- Optimal Control (43)
- Additive Manufacturing (39)
- Neurocontrollers (30)
- Nonlinear Control Systems (28)
-
- Control System Synthesis (21)
- Adaptive Control (20)
- Laser metal deposition (16)
- Stability (16)
- Mechanical properties (14)
- Feedback (13)
- Neural Nets (13)
- Neural Networks (13)
- Microstructure (12)
- Composites (11)
- Robots (11)
- 3D printers (10)
- Deposition (10)
- Finite Element Analysis (10)
- Learning Systems (10)
- Machine learning (10)
- Solid Freeform Fabrication (10)
- Aluminum (9)
- Finite element analysis (9)
- Machine Learning (9)
- Residual stress (9)
- Bioactive glass (8)
- Directed energy deposition (8)
- Distributed Parameter Systems (8)
- Dynamic Programming (8)
- Publication Year
- Publication
-
- Mechanical and Aerospace Engineering Faculty Research & Creative Works (1144)
- Masters Theses (544)
- Doctoral Dissertations (206)
- Materials Science and Engineering Faculty Research & Creative Works (66)
- UMR-MEC Conference on Energy / UMR-DNR Conference on Energy (59)
-
- Electrical and Computer Engineering Faculty Research & Creative Works (31)
- Opportunities for Undergraduate Research Experience Program (OURE) (28)
- Civil, Architectural and Environmental Engineering Faculty Research & Creative Works (22)
- Miners Solving for Tomorrow Research Conference (13)
- NASA-Missouri Space Grant Consortium (12)
- Undergraduate Research Conference at Missouri S&T (12)
- Chemistry Faculty Research & Creative Works (11)
- Engineering Management and Systems Engineering Faculty Research & Creative Works (9)
- Biological Sciences Faculty Research & Creative Works (8)
- Chemical and Biochemical Engineering Faculty Research & Creative Works (8)
- Computer Science Faculty Research & Creative Works (8)
- Professional Degree Theses (7)
- UMR-DNR Conference on Energy (7)
- Mining Engineering Faculty Research & Creative Works (5)
- Psychological Science Faculty Research & Creative Works (5)
- Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works (4)
- Mathematics and Statistics Faculty Research & Creative Works (4)
- Physics Faculty Research & Creative Works (4)
- Missouri S&T’s Peer to Peer (2)
- Bachelors Theses (1)
- Honors Academy (1)
- PSMRC Faculty Research (1)
- Publication Type
Articles 721 - 750 of 2222
Full-Text Articles in Mechanical Engineering
Development Of A Hybrid Manufacturing Process For Precision Metal Parts, Leon Hill, Todd E. Sparks, Frank W. Liou
Development Of A Hybrid Manufacturing Process For Precision Metal Parts, Leon Hill, Todd E. Sparks, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper summarizes the research and development of a hybrid manufacturing process to produce fully dense metal parts with CNC-level precision. High performance metals, such as titanium alloys, nickel superalloys, tool steels, stainless steels, etc. can benefit from this process. Coupling the additive and the subtractive processes into a multi-axis workstation, the hybrid process, can produce and repair metal parts with accuracy. The surface quality of the final product is similar to the industrial milling capability. To achieve such a system, issues of the metal deposition process and the automated process planning of the hybrid manufacturing process will be discussed.
Realizing Structural Color Generation With Aluminum Plasmonic V-Groove Metasurfaces, W. Wang, D. Rosenmann, D. Czaplewski, Xiaodong Yang, Jie Gao
Realizing Structural Color Generation With Aluminum Plasmonic V-Groove Metasurfaces, W. Wang, D. Rosenmann, D. Czaplewski, Xiaodong Yang, Jie Gao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Magnetic Control Of Lateral Migration Of Ellipsoidal Microparticles In Microscale Flows, R. Zhou, C. A. Sobecki, J. Zhang, Yanzhi Zhang, Cheng Wang
Magnetic Control Of Lateral Migration Of Ellipsoidal Microparticles In Microscale Flows, R. Zhou, C. A. Sobecki, J. Zhang, Yanzhi Zhang, Cheng Wang
Mathematics and Statistics Faculty Research & Creative Works
No abstract provided.
Klein Tunneling Near The Dirac Points In Metal-Dielectric Multilayer Metamaterials, L. Sun, Jie Gao, Xiaodong Yang
Klein Tunneling Near The Dirac Points In Metal-Dielectric Multilayer Metamaterials, L. Sun, Jie Gao, Xiaodong Yang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Broadband Polarization Conversion With Anisotropic Plasmonic Metasurfaces, W. Cao, Xiaodong Yang, Jie Gao
Broadband Polarization Conversion With Anisotropic Plasmonic Metasurfaces, W. Cao, Xiaodong Yang, Jie Gao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Structural Vs.. Compositional Disorder In Thermal Conductivity Reduction Of Sige Alloys, Jihui Nie, Raghavan Ranganathan, Zhi Liang, Pawel Keblinski
Structural Vs.. Compositional Disorder In Thermal Conductivity Reduction Of Sige Alloys, Jihui Nie, Raghavan Ranganathan, Zhi Liang, Pawel Keblinski
Mechanical and Aerospace Engineering Faculty Research & Creative Works
We Use Equilibrium Molecular Dynamics Simulations to Determine the Relative Role of Compositional and Structural Disorder in a Phononic Thermal Conductivity Reduction by Studying Three 50-50 SiGe Alloy Structures: Ordered Alloys, Disordered Alloys, and Amorphous Alloys, as Well as Pure Amorphous Si and Ge Structures for Reference. While Both Types of Disorders Significantly Reduce Thermal Conductivity, Structural Disorder is Much More Effective to This Aim. the Examination of Phonon Lifetimes in Disordered Alloys Shows High Values in a Low Frequency Regime Governed by Umklapp Scattering that Are Reduced Rapidly with Increasing Frequency Following Rayleigh Scattering Behavior. the Local Properties Analysis …
Solvent Based 3d Printing Of Biopolymer/Bioactive Glass Composite And Hydrogel For Tissue Engineering Applications, Krishna Kolan, Yong Liu, Jakeb Baldridge, Caroline Murphy, Julie A. Semon, D. E. Day, Ming-Chuan Leu
Solvent Based 3d Printing Of Biopolymer/Bioactive Glass Composite And Hydrogel For Tissue Engineering Applications, Krishna Kolan, Yong Liu, Jakeb Baldridge, Caroline Murphy, Julie A. Semon, D. E. Day, Ming-Chuan Leu
Biological Sciences Faculty Research & Creative Works
Three-dimensional (3D) bioprinting is an emerging technology in which scaffolding materials and cell-laden hydrogels may be deposited in a pre-determined fashion to create 3D porous constructs. A major challenge in 3D bioprinting is the slow degradation of melt deposited biopolymer. In this paper, we describe a new method for printing poly-caprolactone (PCL)/bioactive borate glass composite as a scaffolding material and Pluronic F127 hydrogel as a cell suspension medium. Bioactive borate glass was added to a mixture of PCL and organic solvent to make an extrudable paste using one syringe while hydrogel was extruded and deposited in between the PCL/borate glass …
Effect Of Wall Cooling On Boundary-Layer-Induced Pressure Fluctuations At Mach 6, C. Zhang, Lian Duan, M. Choudhari
Effect Of Wall Cooling On Boundary-Layer-Induced Pressure Fluctuations At Mach 6, C. Zhang, Lian Duan, M. Choudhari
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Design And Analysis Of Adaptive Control Systems Over Wireless Networks, Ali Albattat, Benjamin Gruenwald, Tansel Yucelen
Design And Analysis Of Adaptive Control Systems Over Wireless Networks, Ali Albattat, Benjamin Gruenwald, Tansel Yucelen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper, we study the design and analysis of adaptive control systems over wireless networks using event-triggering control theory. The proposed event-triggered adaptive control methodology schedules the data exchange dependent upon errors exceeding user-defined thresholds to reduce wireless network utilization and guarantees system stability and command following performance in the presence of system uncertainties. Specifically, we analyze stability and boundedness of the overall closed-loop dynamical system, characterize the effect of user-defined thresholds and adaptive controller design parameters to the system performance, and discuss conditions to make the resulting command following performance error sufficiently small. An illustrative numerical example is …
Novel Layered Double Hydroxides-Hydroxyapatite/Gelatin Bone Tissue Engineering Scaffolds: Fabrication, Characterization, And In Vivo Study, Fateme Fayyazbakhsh, Mehran Solati-Hashjin, Abbas Keshtkar, Mohammad Ali Shokrgozar, Mohammad Mehdi Dehghan, Bagher Larijani
Novel Layered Double Hydroxides-Hydroxyapatite/Gelatin Bone Tissue Engineering Scaffolds: Fabrication, Characterization, And In Vivo Study, Fateme Fayyazbakhsh, Mehran Solati-Hashjin, Abbas Keshtkar, Mohammad Ali Shokrgozar, Mohammad Mehdi Dehghan, Bagher Larijani
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Developing Porous Biodegradable Scaffolds through Simple Methods is One of the Main Approaches of Bone Tissue Engineering (BTE). in This Work, a Novel BTE Composite Containing Layered Double Hydroxides (LDH), Hydroxyapatite (HA) and Gelatin (GEL) Was Fabricated using Co-Precipitation and Solvent-Casting Methods. Physiochemical Characterizations Showed that the Chemical Composition and Microstructure of the Scaffolds Were Similar to the Natural Spongy Bone. Interconnected Macropores Ranging over 100 to 600 Μm Were Observed for Both Scaffolds While the Porosity of 90 ± 0.12% and 92.11 ± 0.15%, as Well As, Young's Modulus of 19.8 ± 0.41 and 12.5 ± 0.35 GPa Were …
Stair Negotiation Made Easier Using Novel Interactive Energy-Recycling Assistive Stairs, Yun Seong Song, Sehoon Ha, Hsiang Hsu, Lena H. Ting, C. Karen Liu
Stair Negotiation Made Easier Using Novel Interactive Energy-Recycling Assistive Stairs, Yun Seong Song, Sehoon Ha, Hsiang Hsu, Lena H. Ting, C. Karen Liu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Here we show that novel, energy-recycling stairs reduce the amount of work required for humans to both ascend and descend stairs. Our low-power, interactive, and modular steps can be placed on existing staircases, storing energy during stair descent and returning that energy to the user during stair ascent. Energy is recycled through event-triggered latching and unlatching of passive springs without the use of powered actuators. When ascending the energy-recycling stairs, naive users generated 17.4 ± 6.9% less positive work with their leading legs compared to conventional stairs, with the knee joint positive work reduced by 37.7 ± 10.5%. Users also …
Validation Of Adaptive Control Laws Using Optimization And Trajectory Sensitivity, Mario Luca Fravolini, Antonio Ficola, Fabio Radicioni, Tansel Yucelen, Ehsan Arabi
Validation Of Adaptive Control Laws Using Optimization And Trajectory Sensitivity, Mario Luca Fravolini, Antonio Ficola, Fabio Radicioni, Tansel Yucelen, Ehsan Arabi
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper it is proposed an easy-to-use verification and validation method for adaptive control laws that relies on time domain simulations. The problem is set as a trajectory falsification problem that is the search of closed loop trajectories that, starting from a set of admissible initial conditions, reach a set of unsafe states. The falsification is placed as a nonlinear optimization problem whose decision variables are the initial condition of the states and the uncertain parameters of the system. The falsification is performed iteratively using the local gradient of the sensitivity function derived from a linearized model of the …
A Decentralized Adaptive Control Architecture For Large-Scale Active-Passive Modular Systems, Benjamin C. Gruenwald, Ehsan Arabi, Tansel Yucelen, Animesh Chakravarthy, Drew Mcneely
A Decentralized Adaptive Control Architecture For Large-Scale Active-Passive Modular Systems, Benjamin C. Gruenwald, Ehsan Arabi, Tansel Yucelen, Animesh Chakravarthy, Drew Mcneely
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Decentralized control of large-scale active-passive modular systems is considered. These systems consist of physically interconnected and generally heterogeneous modules, where local control signals can be only applied to a subset of these modules (i.e., active modules) and the rest are not subject to any control signals (i.e., passive modules). Using a set-theoretic adaptive control approach predicated on restricted potential functions, we design decentralized command following control architectures for each active module such that they can effectively perform their tasks with strict performance guarantees in the presence of unknown physical interconnections between modules and module-level system uncertainties. The efficacy of the …
An Algorithm For Enlarging The Region Of Attraction Using Trajectory Reversing, Nilay Kant, Dhrubajit Chowdhury, Ranjan Mukherjee, Hassan K. Khalil
An Algorithm For Enlarging The Region Of Attraction Using Trajectory Reversing, Nilay Kant, Dhrubajit Chowdhury, Ranjan Mukherjee, Hassan K. Khalil
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Trajectory reversing is a method commonly used for estimating the region of attraction of stabilized equilibria. Using a discrete set of points obtained by trajectory reversing, this paper presents an algorithm for estimation and mathematical representation of the region of attraction using convex hulls. Several two-dimensional examples are presented to illustrate the usefulness of the algorithm. The method provides larger estimates compared to that obtained by existing algorithms, but its main advantage lies in its applicability to higher-order systems. The mathematical representation of the region of attraction is useful in applying the Impulse Manifold Method, which was developed for stabilization …
Enlarging The Region Of Attraction Of Equilibria Of Underactuated Systems Using Sum Of Squares And Impulse Manifold Method, Dhrubajit Chowdhury, Nilay Kant, Ranjan Mukherjee, Hassan K. Khalil
Enlarging The Region Of Attraction Of Equilibria Of Underactuated Systems Using Sum Of Squares And Impulse Manifold Method, Dhrubajit Chowdhury, Nilay Kant, Ranjan Mukherjee, Hassan K. Khalil
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper presents an algorithm to enlarge the estimate of the Region of Attraction of stable equilibria of underactuated systems. To achieve this, we use a combination of the Sum of Squares (SOS) method and the Impulse Manifold Method (IMM). Initially, the SOS method is used to optimize the control input u(x) in order to obtain an enlarged Region of Attraction. The IMM is then applied on enlarged Region of Attraction obtained using SOS to further enlarge it. The IMM is implemented using high gain feedback and to demonstrate the efficacy of our algorithm, we present simulation results where an …
Swing-Up Of The Inertia Wheel Pendulum Using Impulsive Torques, Nilay Kant, Ranjan Mukherjee, Hassan K. Khalil
Swing-Up Of The Inertia Wheel Pendulum Using Impulsive Torques, Nilay Kant, Ranjan Mukherjee, Hassan K. Khalil
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The swing-up control problem of the inertia wheel pendulum is revisited in this paper. As different from existing methods, purely impulsive control inputs are used for swing-up. A mathematical formulation of the problem indicates that swing-up can be achieved using impulsive inputs applied at two discrete time instants. Two different swing-up schemes are presented and validated using numerical simulations where the impulsive inputs are approximated by high-gain feedback. The results of numerical simulations establish a direct link between high wheel velocities during swing-up and control strategies that take the pendulum directly to the upright configuration. They also indicate that the …
Quasistatic Error Modeling And Model Testing For A 5-Axis Machine, H-W. Ko, P. Bazzoli, Jared Adam Nisbett, L. Ma, Douglas A. Bristow, Robert G. Landers, Y. Chen, S. Kapoor, P. F. Ferreira
Quasistatic Error Modeling And Model Testing For A 5-Axis Machine, H-W. Ko, P. Bazzoli, Jared Adam Nisbett, L. Ma, Douglas A. Bristow, Robert G. Landers, Y. Chen, S. Kapoor, P. F. Ferreira
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Intensity Control Of Individual Dbd Plasma Filament. I. Experiment With A Needle Electrode, M. C. Paliwoda, J. L. Rovey
Intensity Control Of Individual Dbd Plasma Filament. I. Experiment With A Needle Electrode, M. C. Paliwoda, J. L. Rovey
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Filamentary volume dielectric barrier discharge (DBD) produces patterned plasma structures that are currently being explored for reconfigurable metamaterial applications. In this work, the presence and intensity of a single filament (within an array of filaments) are controlled by biasing a low voltage needle electrode by less than 7% of the driving voltage. The current, voltage, and time-averaged normalized light intensity were measured while varying the needle voltage through self-biasing resistors. For a 7.5 kV, 3.2 kHz DBD in air, the needle-controlled filament intensity varies from 80% to 0% of the light intensity of surrounding filaments. When the biased voltage prevents …
Infrared Metasurfaces Created With Off-Normal Incidence Microsphere Photolithography, Chuang Qu, Edward C. Kinzel
Infrared Metasurfaces Created With Off-Normal Incidence Microsphere Photolithography, Chuang Qu, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Fabricating metasurfaces over large areas at low costs remains a critical challenge to their practical implementation. This paper reports on the use of microsphere photolithography (MPL) to create infrared metasurfaces by changing the angle-of-incidence of the illumination to steer the photonic jet. The displacement of the photonic jet is shown to scale with the diameter of the microsphere while the exposure dose scales with the square of the microsphere diameter. This process is robust in the presence of local defects in the microsphere lattice. The paper demonstrates patterning split ring resonators and tripole based metasurfaces using MPL, which are fabricated …
Intensity Control Of Individual Dbd Plasma Filament. Ii. Fundamental Physical Mechanism, M. C. Paliwoda, J. L. Rovey
Intensity Control Of Individual Dbd Plasma Filament. Ii. Fundamental Physical Mechanism, M. C. Paliwoda, J. L. Rovey
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Filamentary volume dielectric barrier discharge (DBD) produces patterned plasma structures that are currently being explored for reconfigurable metamaterial applications. Previous work has demonstrated control of the presence and intensity of a single DBD plasma filament (within an array of filaments) by biasing a low voltage needle electrode. The results were attributed to redistributed charge inside the DBD due to the modified electric field created by the needle electrode. In the present work, results from a 3D electrodynamic field simulation bolster this argument. Results show that increasing needle bias voltage causes changes in the transverse electric field structure, resulting in redistribution …
Fabrication And Characterization Of Alₓcofenicu₁₋ₓ High Entropy Alloys By Laser Metal Deposition, X. Chen, L. Yan, S. Karnati, Y. Zhang, Frank W. Liou
Fabrication And Characterization Of Alₓcofenicu₁₋ₓ High Entropy Alloys By Laser Metal Deposition, X. Chen, L. Yan, S. Karnati, Y. Zhang, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Phonon Interference In Crystalline And Amorphous Confined Nanoscopic Films, Zhi Liang, Thomas E. Wilson, Pawel Keblinski
Phonon Interference In Crystalline And Amorphous Confined Nanoscopic Films, Zhi Liang, Thomas E. Wilson, Pawel Keblinski
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Using Molecular Dynamics Phonon Wave Packet Simulations, We Study Phonon Transmission Across Hexagonal (H)-BN and Amorphous Silica (A-SiO2) Nanoscopic Thin Films Sandwiched by Two Crystalline Leads. Due to the Phonon Interference Effect, the Frequency-Dependent Phonon Transmission Coefficient in the Case of the Crystalline Film (Si|h-BN|Al Heterostructure) Exhibits a Strongly Oscillatory Behavior. in the Case of the Amorphous Film (Si|a-SiO2|Al and Si|a-SiO2|Si Heterostructures), in Spite of Structural Disorder, the Phonon Transmission Coefficient Also Exhibits Oscillatory Behavior at Low Frequencies (Up to ∼1.2 THz), with a Period of Oscillation Consistent with the Prediction from the Two-Beam …
Work Zone Simulator Analysis: Driver Performance And Acceptance Of Missouri Alternate Lane Shift Configurations, Suzanna Long, Ruwen Qin, Dincer Konur, Ming-Chuan Leu, S. Moradpour, S. Thind, H. Nadathur
Work Zone Simulator Analysis: Driver Performance And Acceptance Of Missouri Alternate Lane Shift Configurations, Suzanna Long, Ruwen Qin, Dincer Konur, Ming-Chuan Leu, S. Moradpour, S. Thind, H. Nadathur
Engineering Management and Systems Engineering Faculty Research & Creative Works
The objective of this project is to evaluate MoDOT’s alternate lane shift sign configuration for work zones. The single signproposed by MoDOT provides the traveler with enough information to let them know that all lanes are available to shift around thework zone, whereas the MUTCD signs require drivers to see two signs. This research simulation project evaluates the drivers’ laneshifting performance and acceptance of the alternate lane shift sign proposed by MoDOT to be used on work zones as compared tothe MUTCD lane shift signs. Based on the study results, no difference was observed between MUTCD lane shift sign andMoDOT …
3d Bioprinting Of Stem Cells And Polymer/Bioactive Glass Composite Scaffolds For Bone Tissue Engineering, Caroline Murphy, Krishna Kolan, Wenbin Li, Julie A. Semon, D. E. Day, Ming-Chuan Leu
3d Bioprinting Of Stem Cells And Polymer/Bioactive Glass Composite Scaffolds For Bone Tissue Engineering, Caroline Murphy, Krishna Kolan, Wenbin Li, Julie A. Semon, D. E. Day, Ming-Chuan Leu
Biological Sciences Faculty Research & Creative Works
A major limitation of using synthetic scaffolds in tissue engineering applications is insufficient angiogenesis in scaffold interior. Bioactive borate glasses have been shown to promote angiogenesis. There is a need to investigate the biofabrication of polymer composites by incorporating borate glass to increase the angiogenic capacity of the fabri-cated scaffolds. In this study, we investigated the bioprinting of human adipose stem cells (ASCs) with a polycaprolac-tone (PCL)/bioactive borate glass composite. Borate glass at the concentration of 10 to 50 weight %, was added to a mixture of PCL and organic solvent to make an extrudable paste. ASCs suspended in Matrigel …
Retarding Field Energy Analyzer For High Energy Pulsed Electron Beam Measurements, J. Hu, Joshua L. Rovey, W. Zhao
Retarding Field Energy Analyzer For High Energy Pulsed Electron Beam Measurements, J. Hu, Joshua L. Rovey, W. Zhao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Resilient Control Of Active-Passive Networked Multiagent Systems In The Presence Of Persistent Disturbances, Dzung Tran, Tansel Yucelen, John Daniel Peterson
Resilient Control Of Active-Passive Networked Multiagent Systems In The Presence Of Persistent Disturbances, Dzung Tran, Tansel Yucelen, John Daniel Peterson
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An active-passive networked multiagent system consists of agents subject to inputs (active agents) and agents without any inputs (passive agents). Specifically, this class of networked multiagent systems utilizes a novel form of dynamic consensus filters, where the states of all agents converge to the average of the exogenous inputs applied only to the active agents, and it has broad practical applications including, for example, real-time situational awareness and data gathering using sensor networks and distributed control of multirobot systems. In this paper, we focus on active-passive networked multiagent systems that are subject to constant and/or harmonic exogenous disturbances. In particular, …
Molecular Simulation Of Steady-State Evaporation And Condensation: Validity Of The Schrage Relationships, Zhi Liang, Thierry Biben, Pawel Keblinski
Molecular Simulation Of Steady-State Evaporation And Condensation: Validity Of The Schrage Relationships, Zhi Liang, Thierry Biben, Pawel Keblinski
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Accuracy, or Even the Validity, of the Schrage Relationships Expressing the Rate of Evaporation and Condensation in Terms of Local Interfacial Thermodynamics Properties and the Mass Accommodation Coefficient is a Subject of Significant Discussion. in This Work, We Carry Out Molecular Dynamics (MD) Simulations of Evaporation and Condensation of Fluid Ar in a Nanochannel. by Adjusting the Temperature Difference, ΔT, between the Evaporating and Condensing Surfaces, We Control the Steady-State Evaporation and Condensation Fluxes (JMD). We Find that Across a Wide ΔT Range Studied, JMD is Always in Excellent Agreement with the Prediction from the Exact Schrage Relationships. Furthermore, …
Assessment Of Multimode Spacecraft Micropropulsion Systems, Steven P. Berg, Joshua L. Rovey
Assessment Of Multimode Spacecraft Micropropulsion Systems, Steven P. Berg, Joshua L. Rovey
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Multimode spacecraft micro propulsion systems that include a high-Thrust chemical mode and high-specific impulse electric mode are assessed with specific reference to CubeSat-sized satellite applications. Both cold-gas butane propellant and ionic liquid chemical monopropellant modes are investigated alongside pulsed plasma, electrospray, and ion electric thruster modes. These systems are studied by varying electric propulsion usage percent and calculating the payload mass fraction and thruster burn time for missions requiring 250, 500, and 1000 m/s delta-V. Systems involving chemical monopropellants have the highest payload mass fractions for a reference mission of 500 m/s delta-V and 6U-sized CubeSat, where 1U is a …
Probabilistic Analysis And Verification Framework For Adaptive Flight Control, Mario Luca Fravolini, Tansel Yucelen, Marcello Napolitano
Probabilistic Analysis And Verification Framework For Adaptive Flight Control, Mario Luca Fravolini, Tansel Yucelen, Marcello Napolitano
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A crucial aspect that could facilitate the applications of adaptive control systems in aerospace applications is the development of effective validation and verification procedures. Most of the existing analysis and design frameworks for adaptive controllers are based on the Lyapunov direct method. One well-known drawback of this approach is the conservatism in the estimation of the uniform ultimate boundedness region with little practical utility. To overcome this limitation, a probabilistic framework for the design of uniform ultimate boundedness regions is proposed where uncertain parameters and adaptive controls are considered as random variables. In this framework, the design is translated into …
Plume Characterization Of Electric Solid Propellant Pulsed Microthrusters, Matthew S. Glascock, Joshua L. Rovey, Shae Williams, Jason Thrasher
Plume Characterization Of Electric Solid Propellant Pulsed Microthrusters, Matthew S. Glascock, Joshua L. Rovey, Shae Williams, Jason Thrasher
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Electric solid propellants are an attractive option for propulsion because they are ignited only by an applied electric current. This leads to capabilities such as on-demand throttling and reignition in chemical combustion operation, and it lends itself to application in electric propulsion. In this work, the plasma plume created by electric solid propellant pulsed micro thrusters is investigated using a nude Faraday probe, a triple Langmuir probe, and residual gas analysis. The thrusters are tested at a vacuum level of 2 x 10-5torr. Results indicate an average plume electron temperature of 1.7 eV and a density of 1011 to 1014cm-3. …