Physical Sciences and Mathematics Commons^™

Spatial Instability Of Electrically Driven Jets With Finite Conductivity And Under Constant Or Variable Applied Field, Saulo Orizaga, Daniel N. Riahi

Applications and Applied Mathematics: An International Journal (AAM)

We investigate the problem of spatial instability of electrically driven viscous jets with finite electrical conductivity and in the presence of either a constant or a variable applied electric field. A mathematical model, which is developed and used for the spatially growing disturbances in electrically driven jet flows, leads to a lengthy equation for the unknown growth rate and frequency of the disturbances. This equation is solved numerically using Newton’s method. For neutral temporal stability boundary, we find, in particular, two new spatial modes of instability under certain conditions. One of these modes is enhanced by the strength Ω of …

Project: F.U.N.B.O.E. (Follow-Up Nucleate Boiling On-Flight Experiment), Getaway Special Team 2009

Education and Outreach

No abstract provided.

Sixth Grade Lesson Plan: Heat Moves, Getaway Special Team 2009

Education and Outreach

No abstract provided.

Third Grade Lesson Plan: Where Does Heat Come From?, Getaway Special Team 2009

Education and Outreach

No abstract provided.

Reinforcement-Learning-Based Output-Feedback Control Of Nonstrict Nonlinear Discrete-Time Systems With Application To Engine Emission Control, Peter Shih, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement-learning-based output adaptive neural network (NN) controller, which is also referred to as the adaptive-critic NN controller, is developed to deliver the desired tracking performance for a class of nonlinear discrete-time systems expressed in nonstrict feedback form in the presence of bounded and unknown disturbances. The adaptive-critic NN controller consists of an observer, a critic, and two action NNs. The observer estimates the states and output, and the two action NNs provide virtual and actual control inputs to the nonlinear discrete-time system. The critic approximates a certain strategic utility function, and the action NNs minimize the strategic utility …

Fifth Grade Lesson Plan: Solid, Liquid, And Gas, Getaway Special Team 2009

Education and Outreach

No abstract provided.

Efficient Simulation Of Fluid Flow, David Hannasch, Monika Neda

Undergraduate Research Opportunities Program (UROP)

We are computationally investigating fluid flow models for physically correct predictions of flow structures. Models based on the idea of filtering the small scales/structures and also the Navier-Stokes equations which are the fundamental equations of fluid flow, are numerically solved via the continuous finite element method. Crank-Nicolson and fractional-step theta scheme are used for the discretization of the time derivative, while the Taylor-Hood and Mini elements are used for the discretization is space. The effectiveness of these numerical discretizations in time and space are examined by studying the accuracy of fluid characteristics, such as drag, lift and pressure drop.

A Study Of Decision Analysis Methods In Aerospace Technology Assessments, Sharon Monica Jones

Engineering Management & Systems Engineering Theses & Dissertations

Managers of aerospace technology programs and projects are faced with the challenge of making technology portfolio decisions under conditions of limited data, rapidly changing macro level factors and organizational uncertainties. To help make these technology investment decisions, some aerospace managers and analysts have used techniques from the field of decision analysis. In addition, there have been a limited number of research studies of real decision problems.

This dissertation presents the results of a non-experimental examination of the use of decision analysis methods for the assessment of aerospace technology portfolios. A web-based survey instrument was developed based on the results of …

Strongly Coupled Computation Of Material Response And Nonequilibrium Flow For Hypersonic Ablation, Alexandre Martin, Iain D. Boyd

Alexandre Martin

A one-dimensional material response implicit solver with surface ablation and pyrolysis is strongly coupled to LeMANS, a CFD code for the simulation of weakly ionized hypersonic flows in thermo-chemical non-equilibrium. Using blowing wall boundary conditions and a moving mesh algorithm, the results of a strongly coupled solution of a re-entry problem are presented, using the well defined case of the IRV-2 vehicle. Results are compared to other coupled codes and show good agreement with published numerical results.

Store And Forward Routing For Sparse Pico-Satellite Sensor Networks With Data-Mules, Trevor Joseph Koritza

Master's Theses

Satellites are playing an increasingly important role in collecting scientific information, providing communication services, and revolutionizing navigation. Until recently satellites were large and very expensive, creating a high barrier to entry that only large corporations and government agencies could overcome. In the past few years the CubeSat project at California Polytechnic University in San Luis Obispo (Cal Poly) has worked to refine the design and launching of small, lightweight, and less expensive satellites called pico-satellites, opening space up to a wider audience. Now that Cal Poly has the launch logistics and hardware under control, a new problem has arisen. These …

Turn Constrained Path Planning Problems, Victor M. Roman

UNLV Theses, Dissertations, Professional Papers, and Capstones

We consider the problem of constructing multiple disjoint paths connecting a source point s to a target point t in a geometric graph. We require that the paths do not have any sharp turn angles. We present a review of turn constrained path planning algorithms and also algorithms for constructing disjoint paths. We then combine these techniques and present an O(nlogn) time algorithm for constructing a pair of edge disjoint turn constrained paths connecting two nodes in a planar geometric graph. We also consider the development of a turn constrained shortest path map in the presence of …

Characterization Of Microwave Cavity Discharges In A Supersonic Flow, Dareth Janette Drake

Physics Theses & Dissertations

A partially ionized gas is referred to as either a plasma or a discharge depending on the degree of ionization. The term discharge is usually applied to a weakly ionized gas, i.e. mostly neutrals, where as a plasma usually has a larger degree of ionization. To characterize a discharge the plasma parameters, such as the rotational temperature, vibrational temperature, and electron density, must be determined. Detailed characterization of supersonic flowing discharges is important to many applications in aerospace and aerodynamics. One application is the use of plasma-assisted hydrogen combustion devices to aid in supersonic combustion. In conditions close to the …

Microgravity Experiments For The Iss, Justin Koeln, Jan Sojka

Posters

The Get Away Special (GAS) team is a microgravity research team known for leading Utah State University to the impressive distinction of flying more experiments in space than any other university in the world. The following experiments were designed by the GAS team after receiving the opportunity to develop and experiment to be performed by a Space Flight Participant aboard the International Space Station (ISS).

Cooperative Unmanned Aerial Surveillance Control System Architecture, Theodore T. Diamond, Adam L. Rutherford, Jonathan B. Taylor

Theses and Dissertations

Intelligence, surveillance and reconnaissance (ISR) is a high-demand Department of Defense mission performed by unmanned aircraft systems (UASs) at the tactical and theater levels. Coordinating UASs through cooperative control offers the advantages of persistence, distributed and adaptable sensor coverage, and reduced revisit time on points of interest. The purpose of this thesis is to apply systems engineering principles to the problem of developing a flexible, common control system for cooperative UAS surveillance at the tactical level. The AFIT team developed a concept of operations (CONOPS) encompassing various users and surveillance tasks. The team then used the scenarios in the CONOPS …

Waypoint Generation Based On Sensor Aimpoint, Shannon M. Farrell

Theses and Dissertations

Secretary of Defense Robert M. Gates has emphasized a need for a greater number of intelligence, surveillance, and reconnaissance (ISR) assets to support combatant commanders and military operations globally. Unmanned systems, especially MAVs, used as ISR platforms provide the ability to maintain covertness during missions and help reduce the risk to human life. This research develops waypoint generation algorithms required to keep a point of interest (POI) in the field of view (FOV) of a fixed sensor on a micro air vehicle (MAV) in the presence of a constant wind.
Fixed sensors, while cheaper and less prone to mechanical failure …

Predicting Solar Protons: A Statistical Approach, Jonathan C. Spaulding

Theses and Dissertations

A small fraction of solar flares are accompanied by high energy (>10 MeV) protons. These events can cause degradation or failure of satellite systems and can be harmful to humans in space or in high altitude flight. For risk management purposes, the Air Force is interested in predicting these events. Several algorithms exist to do this operationally, but none predict when these events will occur with much accuracy. Here, we analyzed 3610 M1 and greater flares including 106 with proton events from the GOES sensors from 1 Jan 1986 to 31 Dec 2004 to produce new results, including a …

Hyperspectral Imaging Of A Turbine Engine Exhaust Plume To Determine Radiance, Temperature, And Concentration Spatial Distributions, Spencer J. Bowen

Theses and Dissertations

The usefulness of imaging Fourier transform spectroscopy (IFTS) when looking at a rapidly varying turbine engine exhaust scene was explored by characterizing the scene change artifacts (SCAs) present in the plume and the effect they have on the calibrated spectra using the Telops, Inc.-manufactured Field-portable Imaging Radiometric Spectrometer Technology, Midwave Extended (FIRST-MWE). It was determined that IFTS technology can be applied to the problem of a rapidly varying turbine engine exhaust plume due to the zero mean, stochastic nature of the SCAs, through the use of temporal averaging. The FIRST-MWE produced radiometrically calibrated hyperspectral datacubes, with calibration uncertainty of 35% …

Using Agent-Based Modeling To Evaluate Uas Behaviors In A Target-Rich Environment, Joseph A. Van Kuiken

Theses and Dissertations

The trade-off between accuracy and speed is a re-occurring dilemma in many facets of military performance evaluation. This is an especially important issue in the world of ISR. One of the most progressive areas of ISR capabilities has been the utilization of Unmanned Aircraft Systems (UAS). Many people believe that the future of UAS lies in smaller vehicles flying in swarms. We use the agent-based System Effectiveness and Analysis Simulation (SEAS) to create a simulation environment where different configurations of UAS vehicles can process targets and provide output that allows us to gain insight into the benefits and drawbacks of …

Architecting Human Operator Trust In Automation To Improve System Effectiveness In Multiple Unmanned Aerial Vehicles (Uav), Eric A. Cring, Adam G. Lenfestey

Theses and Dissertations

Current Unmanned Aerial System (UAS) designs require multiple operators for each vehicle, partly due to imperfect automation matched with the complex operational environment. This study examines the effectiveness of future UAS automation by explicitly addressing the human/machine trust relationship during system architecting. A pedigreed engineering model of trust between human and machine was developed and applied to a laboratory-developed micro-UAS for Special Operations. This unprecedented investigation answered three primary questions. Can previous research be used to create a useful trust model for systems engineering? How can trust be considered explicitly within the DoD Architecture Framework? Can the utility of architecting …

Probabilistic Estimation Of Rare Random Collisions In 3-Space, Timothy Holzmann

Theses and Dissertations

A study of risk assessment for artillery fire randomly colliding with fixed wing aircraft is presented. The research lends itself to a general study of collision models. Current models of object collisions fall under one of three categories: the historical model, the gas particle model, and the satellite model. These three vary in data requirements and mathematical representation of the impact event. The gas particle model is selected for its flexibility and robust estimation. However, current mathematical development in the literature does not include certain spatial and dynamic components necessary for a general encounter (collision) model. These are derived in …

Using Predictive Rendering As A Vision-Aided Technique For Autonomous Aerial Refueling, Adam D. Weaver

Theses and Dissertations

This research effort seeks to characterize a vision-aided approach for an Unmanned Aerial System (UAS) to autonomously determine relative position to another aircraft in a formation, specifically to address the autonomous aerial refueling problem. A system consisting of a monocular digital camera coupled with inertial sensors onboard the UAS is analyzed for feasibility of using this vision-aided approach. A three-dimensional rendering of the tanker aircraft is used to generate predicted images of the tanker as seen by the receiver aircraft. A rigorous error model is developed to model the relative dynamics between an INS-equipped receiver and the tanker aircraft. A …

Rembrant: Research On The Effects Of Microgravity On The Brazil Nut Problem, Getaway Special Team 2009

Reports and Proposals

No abstract provided.

Gathering Leadership Momentum Across Great Distances: Creating An Online Community Of Practice, Erin L. Davis, Danielle Theiss-White

Erin Davis

At the 2007 Mountain Plains Library Association Leadership (MPLA) Institute, held in New Mexico, USA, eight academic librarians formed an online multi-state, multigenerational community of practice. MPLA is a twelve-state library association within the United States. Using Google Groups™, the members formed an online environment called the MPLA Community of Practice for continuing development of the leadership skills presented at the Institute. These early-career librarians represent diverse educational backgrounds and work in libraries serving varied populations with differing disciplinary emphases.

The group meets monthly with each member preparing and facilitating online discussions, complete with personal assessments, topical readings, and questions. …

Funboe Factsheet, Getaway Special Team 2009

Reports and Proposals

No abstract provided.

Ipas: International Paper Airplanes In Space, Getaway Special Team 2009

Reports and Proposals

No abstract provided.

Sides: Space Italian Dressing Experimental Setup, Getaway Special Team 2009

Reports and Proposals

No abstract provided.

Invited Article: Data Analysis Of The Floating Potential Measurement Unit Aboard The International Space Station, Aroh Barjatya, Charles M. Swenson, Donald C. Thompson, Kenneth H. Wright

Publications

We present data from the Floating Potential Measurement Unit (FPMU) that is deployed on the starboard truss of the International Space Station. The FPMU is a suite of instruments capable of redundant measurements of various plasma parameters. The instrument suite consists of a floating potential probe, a wide-sweeping spherical Langmuir probe, a narrow-sweeping cylindrical Langmuir probe, and a plasma impedance probe. This paper gives a brief overview of the instrumentation and the received data quality, and then presents the algorithm used to reduce I-V curves to plasma parameters. Several hours of data are presented from August 5, 2006 and March …

Gathering Leadership Momentum Across Great Distances: Creating An Online Community Of Practice, Erin Dini-Davis, Danielle Theiss-White

Library Faculty & Staff Publications

At the 2007 Mountain Plains Library Association Leadership (MPLA) Institute, held in New Mexico, USA, eight academic librarians formed an online multi-state, multigenerational community of practice. MPLA is a twelve-state library association within the United States. Using Google Groups™, the members formed an online environment called the MPLA Community of Practice for continuing development of the leadership skills presented at the Institute. These early-career librarians represent diverse educational backgrounds and work in libraries serving varied populations with differing disciplinary emphases. The group meets monthly with each member preparing and facilitating online discussions, complete with personal assessments, topical readings, and questions. …

Semi-Automated Frame Transformations Using Fft Analysis On 2-D Images, Francisco Javier Osuna

Open Access Theses & Dissertations

Cassini entered Saturn's orbit on July 1, 2004 beginning a four-year exploration of Saturn. In 2008 the mission was extended, and Cassini continues to collect and transmit images and data collected during its mission. In order to accurately interpret images, it is necessary to know the location and orientation of the camera provided the field of view when the image was collected. While the mission managers provide initial estimates of this orientation, scientific analysis requires better estimates than the initial data provided. Navigation is a process for improving the estimation of the true camera pointing vector as determined by features …

Volume Viscosity In Fluids With Multiple Dissipative Processes, Allan J. Zuckerwar, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

The variational principle of Hamilton is applied to derive the volume viscosity coefficients of a reacting fluid with multiple dissipative processes. The procedure, as in the case of a single dissipative process, yields two dissipative terms in the Navier-Stokes equation: The first is the traditional volume viscosity term, proportional to the dilatational component of the velocity; the second term is proportional to the material time derivative of the pressure gradient. Each dissipative process is assumed to be independent of the others. In a fluid comprising a single constituent with multiple relaxation processes, the relaxation times of the multiple processes are …