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Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu 2019 Laboratoire des Signaux et Syst`emes (L2S) CentraleSup´elec-CNRS-Universit´e Paris Sud, 3 rue Joliot- Curie 91192 Gif-sur-Yvette cedex, France.

Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper presents a systematic method to analyse the stability of systems with single delay in which the coefficient polynomials of the characteristic equation depend on the delay. Such systems often arise in, for example, life science and engineering systems. A method to analyze such systems was presented by Beretta and Kuang in a 2002 paper, but with some very restrictive assumptions. This work extends their results to the general case with the exception of some degenerate cases. It is found that a much richer behavior is possible when the restrictive assumptions are removed. The interval of interest for the ...


Additively-Manufactured Hybrid Rocket Consumable Structure For Cubesat Propulsion, Britany L. Chamberlain 2018 Utah State University

Additively-Manufactured Hybrid Rocket Consumable Structure For Cubesat Propulsion, Britany L. Chamberlain

All Graduate Theses and Dissertations

Three-dimensional, additive printing has emerged as an exciting new technology for the design and manufacture of small spacecraft systems. Using 3-D printed thermoplastic materials, hybrid rocket fuel grains can be printed with nearly any cross-sectional shape, and embedded cavities are easily achieved. Applying this technology to print fuel materials directly into a CubeSat frame results in an efficient, cost-effective alternative to existing CubeSat propulsion systems. Different 3-D printed materials and geometries were evaluated for their performance as propellants and as structural elements. Prototype "thrust columns" with embedded fuel ports were printed from a combination of acrylonitrile utadiene styrene (ABS) and ...


Experimental Investigation Of A Green Hybrid Thruster Using A Moderately Enriched Compressed Air As The Oxidizer, Marc Anthony Bulcher 2018 Utah State University

Experimental Investigation Of A Green Hybrid Thruster Using A Moderately Enriched Compressed Air As The Oxidizer, Marc Anthony Bulcher

All Graduate Theses and Dissertations

A hybrid rocket is a propulsion system that uses propellants in two different phases, typically a solid fuel inside the combustion chamber and a separate gaseous or liquid oxidizer stored in a tank. Hybrid rockets are an area of research interest because of their low explosive risk, inexpensive components, and high degree of reliability. In the Propulsion Research Laboratory at Utah State University, pure oxygen is among the top choice for hybrid rocket oxidizers due to its low cost and ease of storage. When paired with a solid fuel known as ABS (acrylonitrile butadiene styrene) plastic, specific impulse values exceed ...


Autonomous Trajectory Planning For Satellite Rpo And Safety Of Flight Using Convex Optimization, Nicholas G. Ortolano 2018 Utah State University

Autonomous Trajectory Planning For Satellite Rpo And Safety Of Flight Using Convex Optimization, Nicholas G. Ortolano

All Graduate Theses and Dissertations

Optimal trajectory planning methods that implement convex optimization techniques are applied to the area of satellite rendezvous and proximity operations. This involves the development of linearized relative orbital motion dynamics and constraints for two satellites, where one maintains a near-circular reference orbit. The result is formulated as a convex optimization problem, where the objective is to minimize the amount of fuel required to transfer from a given initial condition to the desired final conditions. A traditional rendezvous and proximity operations scenario is analyzed, which includes examples of initial approach, inspection, final approach, and docking trajectories. This scenario may include trajectory ...


Toward Building Resilient, Sustainable, And Smart Infrastructure In The 21st Century, Aly Mousaad Aly 2018 Louisiana State University

Toward Building Resilient, Sustainable, And Smart Infrastructure In The 21st Century, Aly Mousaad Aly

Faculty Publications

In recent years, as a result of significant climate change, stringent windstorms are becoming more frequent than before. Given the threat that windstorms bring to people and property, wind/structural engineering research is imperative to improve the resilience of existing and new infrastructure, for community safety and assets protection. The Windstorm Impact, Science and Engineering (WISE) research program at Louisiana State University (LSU) focuses on creating new knowledge applicable to the mitigation of existing and new infrastructure, to survive and perform optimally under natural hazards. To achieve our research goals, we address two imperious challenges: (i) characterization of realistic wind ...


Optimal Attitude Control Of A Two-Cubesat Virtual Telescope In A Highly Elliptical Orbit, reza pirayeshshirazinezhad 2018 University of New Mexico - Main Campus

Optimal Attitude Control Of A Two-Cubesat Virtual Telescope In A Highly Elliptical Orbit, Reza Pirayeshshirazinezhad

Shared Knowledge Conference

This paper investigates a novel approach for attitude control of 2 satellites acting as a virtual telescope. The Virtual Telescope for X-ray Observations (VTXO) is a mission exploiting 2 6U-CubeSats operating in a precision formation. The goal of the VTXO project is to develop a space-based, X-ray imaging telescope with high angular resolution precision. In this scheme, one CubeSat carries a diffractive lens and the other one carries an imaging device to support a focal length of 100 m. In this mission, the attitude control algorithms are required to keep the two spacecraft in alignment with the Crab Nebula observations ...


Pulsed Fiber Optics Lasers As Highly Sensitive Sensors, Hanieh Afkhamiardakani 2018 University of New Mexico

Pulsed Fiber Optics Lasers As Highly Sensitive Sensors, Hanieh Afkhamiardakani

Shared Knowledge Conference

An interferometer or resonator is a device in which optical beams of specific frequencies circulate with minimal losses. These losses are completely compensated by the gain inside a laser resonator. A small perturbation introduced inside the laser can affect its frequency, which in turns becomes a metric of that perturbation. The perturbation is usually caused by an electric or magnetic field, rotation, acceleration, nonlinear index of refraction etc. Tiny changes of optical frequency are monitored by superimposing the laser field and a reference field (from the same laser) on a detector. This technique requires creating a laser in which two ...


Enhancing Your Intelligence Agency Information Resource Iq: Pt. 4: National Geospatial Intelligence Agency (Ngia), National Intelligence University (Niu), And National Reconnaissance Office (Nro), Bert Chapman 2018 Purdue University

Enhancing Your Intelligence Agency Information Resource Iq: Pt. 4: National Geospatial Intelligence Agency (Ngia), National Intelligence University (Niu), And National Reconnaissance Office (Nro), Bert Chapman

Libraries Faculty and Staff Presentations

Webinar presentation on publicly accessible information resources produced by the U.S. National Geospatial Intelligence Agency (NGIA), National Intelligence University (NIU), and National Reconnaissance Office. Places significant emphasis on missions of these agencies, their historical accomplishments, coverage of their educational activity, and information on the technologies they have used and are currently using to fulfill their institutional objectives.


Study Of Differential Diffusion Using Backward Trajectories In Turbulence, Adyasha Mohanty 2018 Georgia Institute of Technology

Study Of Differential Diffusion Using Backward Trajectories In Turbulence, Adyasha Mohanty

Georgia Undergraduate Research Conference (GURC)

Molecular diffusion due to turbulent dispersion plays a crucial role in pollutant spreading and flame stabilization. Molecules in fluid flow undergo Brownian motion at a rate determined by their molecular diffusivity or Schmidt number (Sc). In this research we investigate differential diffusion of molecules for two sets of molecular pairs, one in high diffusivity regime (Sc of 0.001 and 0.01) and one in the low diffusivity regime (Sc of 100 and 1000) that provides us statistical relations between properties of each diffusing substance due to different molecular diffusivities. Direct numerical simulation with parallel computing is first used to ...


Liquid Jet Penetration And Breakup In A Free Supersonic Gas Jet, Hansen Jones 2018 Louisiana State University

Liquid Jet Penetration And Breakup In A Free Supersonic Gas Jet, Hansen Jones

LSU Master's Theses

In the testing of today’s rocket engines, both on large scale vertical test stands and smaller subscale horizontal component testing stands, it is extremely important to be able to accurately quantify and mitigate the thermal and acoustic loads the engines will generate on test stand infrastructure. Due to the large number of parameters that must be considered for many cases, development of a multi-phase computational code is under way to properly analyze and design water spray cooling systems used at NASA’s Stennis Space Center (SSC) and across other NASA centers. As such, a small-scale experiment has been conducted ...


Computational Aerodynamics And Anatomical Characterization Of Laryngotracheal Stenosis In Children, William Poynot 2018 Louisiana State University

Computational Aerodynamics And Anatomical Characterization Of Laryngotracheal Stenosis In Children, William Poynot

LSU Master's Theses

Laryngotracheal stenosis (LTS) is a health condition in which an obstruction in the upper trachea can cause breathing difficulties and increased incidence of infection, among other symptoms. Occurring most commonly due to intubation in infants, LTS often requires corrective surgery. Currently, clinical methods of assessing the blockage region are simplistic and subjective, and it is challenging to determine the most effective surgical strategy for any given patient. In the present work, a comprehensive methodology is proposed for characterizing the stenosis region both in terms of its anatomical parameters and its corresponding aerodynamic properties. The combination of computational fluid dynamics (CFD ...


The Subject Librarian Newsletter, Engineering And Computer Science, Spring 2018, Buenaventura "Ven" Basco 2018 University of Central Florida

The Subject Librarian Newsletter, Engineering And Computer Science, Spring 2018, Buenaventura "Ven" Basco

Buenaventura "Ven" Basco

No abstract provided.


The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2017, Buenaventura "Ven" Basco 2018 University of Central Florida

The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2017, Buenaventura "Ven" Basco

Buenaventura "Ven" Basco

No abstract provided.


Julia Language Ephemeris And Physical Constants Reader For Solar System Bodies, Julia Mihaylov, Renee Spear 2018 Embry-Riddle Aeronautical University

Julia Language Ephemeris And Physical Constants Reader For Solar System Bodies, Julia Mihaylov, Renee Spear

Undergraduate Research Symposium - Prescott

This presentation was the forerunner a second paper by the authors for the AAS/AIAA conference in January 2019, and is not available for download. For a description of the first presentation, see the authors' Discovery Day 2018 - Presentation.

Publicly released in 2012, the Julia language is a relatively new, open source dynamic language. One major benefit of Julia is its combined capabilities of both dynamic and static coding languages. It nearly matches the computational efficiency of static languages, such as FORTRAN or C, and exceeds that of dynamic languages, such as MATLAB or Python. Additionally, unlike Python, Julia was ...


Design Of A Heavy Lift Rc Aircraft - Society Of Automotive Engineers (Sae) Aero Design® West Competition Team, Jiyoung Hwang, Phillip Nielsen 2018 Embry-Riddle Aeronautical University

Design Of A Heavy Lift Rc Aircraft - Society Of Automotive Engineers (Sae) Aero Design® West Competition Team, Jiyoung Hwang, Phillip Nielsen

Undergraduate Research Symposium - Prescott

The SAE Aero West design competition challenges undergraduate students to design and build an RC aircraft that will fly with the maximum number of passengers and luggage possible. The ERAU SAE team focuses on simulation-based research and project methods such as Computational Fluid Dynamics (CFD), aircraft optimization, and Finite Element Analysis (FEA). Designing and manufacturing a well-designed heavy lift aircraft and competing with other groups will give experience in solving engineering problems. The Aerodynamics team is currently focusing on score optimization, aircraft performance and configuration. The propulsion team is constructing a test rig to test various propellers and motors to ...


Design Of A Thrust Stand For Low Power Electric Propulsion, John Norton 2018 Embry-Riddle Aeronautical University

Design Of A Thrust Stand For Low Power Electric Propulsion, John Norton

Undergraduate Research Symposium - Prescott

Electric propulsion (EP) has been gaining popularity due to the high efficiencies and specific impulse. These thrusters all follow the same general idea of converting stored electrical potential energy to kinetic energy for the craft; typically, this is accomplished by the acceleration of gas particles through three main methods, electrothermal, electromagnetic, and/or electrostatic. The specific impulse is the change of momentum per unit of propellant expended. While chemical propulsion produces a high change in momentum, they use much more propellant mass than an electric thruster. EP devices will typically produce very low thrust, which makes it difficult to measure ...


Eagle Aero Sport: Student-Built Aircraft, Rachael Bradshaw, Nick Bartholet 2018 Embry-Riddle Aeronautical University

Eagle Aero Sport: Student-Built Aircraft, Rachael Bradshaw, Nick Bartholet

Undergraduate Research Symposium - Prescott

Eagle Aero Sport (EAS) is the first student operated aircraft build team at Embry-Riddle Aeronautical University. Our team allows students to gain hands-on experience in all aspects of aircraft production including: aircraft assembly, design engineering, management of production operations, finance, marketing, and team building skills. Through research, and consulting with the Experimental Aircraft Association, our airplane of choice is the Van’s RV-12. EAS is modifying the airplane to add real time flight test instrumentation for research. These instruments will gather data for aerodynamic, structural, as well as aircraft performance experiments. Presently, EAS is progressing with Build Team 60% complete ...


Intelligent Strain Sensing On A Smart Composite Wing Using Extrinsic Fabry-Perot Interferometric Sensors And Neural Networks, Kakkattukuzhy M. Isaac, Donald C. Wunsch, Steve Eugene Watkins, Rohit Dua, V. M. Eller 2018 Missouri University of Science and Technology

Intelligent Strain Sensing On A Smart Composite Wing Using Extrinsic Fabry-Perot Interferometric Sensors And Neural Networks, Kakkattukuzhy M. Isaac, Donald C. Wunsch, Steve Eugene Watkins, Rohit Dua, V. M. Eller

Donald C. Wunsch

Strain prediction at various locations on a smart composite wing can provide useful information on its aerodynamic condition. The smart wing consisted of a glass/epoxy composite beam with three extrinsic Fabry-Perot interferometric (EFPI) sensors mounted at three different locations near the wing root. Strain acting on the three sensors at different air speeds and angles-of-attack were experimentally obtained in a closed circuit wind tunnel under normal conditions of operation. A function mapping the angle of attack and air speed to the strains on the three sensors was simulated using feedforward neural networks trained using a backpropagation training algorithm. This ...


Detection And Classification Of Impact-Induced Damage In Composite Plates Using Neural Networks, Rohit Dua, Steve Eugene Watkins, Donald C. Wunsch, K. Chandrashekhara, Farhad Akhavan 2018 Missouri University of Science and Technology

Detection And Classification Of Impact-Induced Damage In Composite Plates Using Neural Networks, Rohit Dua, Steve Eugene Watkins, Donald C. Wunsch, K. Chandrashekhara, Farhad Akhavan

Donald C. Wunsch

Artificial neutral networks (ANN) can be used as an online health monitoring systems (involving damage assessment, fatigue monitoring and delamination detection) for composite structures owing to their inherent fast computing speeds, parallel processing and ability to learn and adapt to the experimental data. The amount of impact-induced strain on a composite structure can be found using strain sensors attached to composite structures. Prior work has shown that strain-based ANN can characterize impact energy on composite plates and that strain signatures can be associated with damage types and severity. This paper reports the extension of this approach for damage classification using ...


Brake Update For Champ And Chief, James Spee 2018 University of Redlands

Brake Update For Champ And Chief, James Spee

James Spee

This is an update to a previous article in Aeronca Aviator about converting 1940's vintage Aeronca aircraft from mechanical brakes to modern hydraulic brakes. This article solves the need of Aeronca Chief owners for a bolt on conversion that maintains their original brake pedals and hides the hydraulic system under the floorboards.

Aeronca Aviator is the newsletter of the Aeronca Aviators Club, a support group for owners of vintage aircraft produced in Middletown and Cincinnati, Ohio, from the 1930s to the early 1950s.


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