Engineering Commons^™

Current Developments In Space Infrastructure: Space Horizons 2014, Mason Peck

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Mason Peck on "Current Developments in Space Infrastructure: Space Horizons 2014" from February 20, 2014.

Quasars And Pulsars And Masers (Oh, My!), Michael Hecht

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Michael Hecht on "Quasars and Pulsars and Masers (Oh, my!)" from February 19, 2014.

Pocketqubes: Access To Space Infrastructure For Small Organizations, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "PocketQubes: Access to space infrastructure for small organizations" from February 19, 2014.

Pocketqubes: Access To Space Infrastructure For Small Organizations, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "PocketQubes: Access to space infrastructure for small organizations" from February 19, 2014.

Comm-Link Equations - Loose Slides, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Comm-Link Equations" from February 13, 2014.

Computer Data Busses, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Computer Data Busses" from February 13, 2014.

Commincations - Deicibel, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Comminications - Decibel" from February 11, 2014.

Communications - Decibel, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Communications - Decibel" from February 11, 2014.

The Origin Of Interferometric Effect Involving Surface Plasmon Polariton In Scattering Near-Field Scanning Optical Microscopy, Yan Li, Nan Zhou, Edward C. Kinzel, Xifeng Ren, Xianfan Xu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Scattering near-field scanning optical microscopy (s-NSOM) has been developed to characterize optical near field with spatial resolution on the order of 10 nm. In this work we report investigation of the interferometric patterns commonly occurred in s-NSOM measurements. To reveal the origin of such interference patterns, a simple nano slit is used. Comparing the measured result with a simplified analytical model as well as full-field numerical simulations, it is shown that the interference pattern is predominantly formed by the in-plane component of incidence light and surface plasmon polariton (SPP) launched by the nano slit. This result helps to understand the …

Liquid Slosh Analysis Using Smoothed Particle Hydrodynamics, Kristopher S. Field

Doctoral Dissertations and Master's Theses

The purpose of the research described here is to study the implementation of Smoothed Particle Hydrodynamics (SPH) algorithms as an adequate means for propellant slosh simulations in 1g and 0g environments. The dualSPHysics solver has been adapted for propellant slosh simulations. Simulated sloshing liquid frequency and damping ratio data for 1g cases has been compared to existing experiments for both spherical and prismatic container geometries. The 0g case has been studied to determine what further modifications would be required to obtain realistic simulations results. The findings in this research will be used to create a sloshing simulation to determine torques …

Power Storage & Control: Review With Questions, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Power Storage & Control: Review with Questions" from February 4, 2015.

Statistics Based Modeling Of Wind Speed And Wind Direction In Real Time Optimal Guidance Strategies Via Ornstein-Uhlenbeck Stochastic Processes, Kamran Turkoglu

Faculty Publications

No abstract provided.

Test Case Series 3, Tom Van Eekelen, Alexandre Martin, Jean Lachaud, Daniele Bianchi

Ablation Workshop: Code Comparison

Numerical simulation of ablative-material response: code and model comparisons

Femtosecond And Nanosecond Dual-Laser Optical Emission Spectroscopy Of Gas Mixtures, Cheng Hsiang Lin, Zhi Liang, Jun Zhou, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Method Employing an Integrated Femtosecond (Fs) and Nanosecond (Ns) Dual-Laser System Was Developed to Generate Plasma with Desired Radical Species from Gas Mixtures Via a Fs Laser Pulse and Then to Excite Selected Radical Species to Higher Electronic States using a Wavelength-Tunable Ns Laser Pulse. an Optical Spectrometer Was Used to Measure the Emission Spectra and Identify the Transition from the Excited Electronic State to the Ground State. the Proposed Technique Has Been Demonstrated for an N2-CO2 Mixture with Various Time Delays between the Two Fs and Ns Pulses. the Results Have Indicated that the Population of Selected Radical …

Study The Effects Of Core Orientation And Different Face Thicknesses On Mechanical Behavior Of Honeycomb Sandwich Structures Under Three Point Bending, Joshua M. Lister

Master's Theses

This study will present the Experimental, numerical and analytical characterizations of composite sandwich structures needed to optimize structure design. In this study, the effects of varying honeycomb core ribbon orientation and varying face sheet thickness’s have on the flexural behavior of honeycomb sandwich structures was investigated. Honeycomb sandwich panels were constructed using Hexcel 6367 A250-5H carbon fiber face sheets and Hexcel Nomex HRH-10-1/8-5 honeycomb cores. The mechanical properties of the constituent materials were discovered experimentally using ASTM standards and theoretical models using honeycomb mechanics and classical beam and plate theory are described. A failure mode map for loading under three …

Nasa Human Exploration Rover Challenge, Estelle Fortes, Aaron Taylor, Caitlin Talerico, Jessica Chow, Jessica Turcios, Johnnie Perry, Joshua Beck, Juana Cecilia Martin-Gonzalez, Lisa Ferguson, Michaela Branscomb, Mo Sabliny, Raeann Vansickle, Sarah Pearson, Sierra Dryer, Zach Henney, Brenda Haven

Aviation / Aeronautics / Aerospace International Research Conference

NASA's Great Moonbuggy Race, held annually in at the Marshall Space Flight Center in Huntsville, Alabama, is an engineering design challenge that asks teams of student engineers to design a human-­‐powered vehicle capable of traversing a simulated lunar surface. However, there is an interesCng sCpulaCon in the design of the moonbuggy: it must be able to be transported in a 4x4x4 foot cube, echoing the design constraint faced by the engineers who built the Lunar Roving Vehicles used by the astronauts of the later Apollo missions. The vehicle in this proposal, Ocelot, designed by the Society of Women Engineers at …

Applications Of Long-Wave Thermal Infrared Imagers On Unmanned Aerial Systems For First Responders, Nick Harris, Lorenzo Coykendall

Aviation / Aeronautics / Aerospace International Research Conference

The Embry-Riddle Prescott UAS Team will design, build, and test three Unmanned Aerial Systems (UAS) for competing in the student UAS Competition June 18 - 22 in Patuxent River, MD hosted by the Association for Unmanned Vehicle Systems International (AUVSI).

The team will design and build these unmanned aircraft to carry a five-pound payload, sustain flight for at least forty minutes, and be hand-launchable and rugged; they will be constructed from composite materials and will be fully autonomous through the use of open-source autopilots.

Angle Of Attack Equipment In General Aviation Operations, Marshall Pomeroy, Justin Abrams, Shawn Pruchnicki, Seth Young

Aviation / Aeronautics / Aerospace International Research Conference

The Federal Aviation Administration (FAA) in conjunction with the general aviation (GA) industry formed the General Aviation Joint Steering Committee (GAJSC) with the goal to improve overall general aviation safety.

• The GAJSC tasked their technical division, the Safety Analysis Team (SAT), with identifying safety issues present within GA. Upon review of fatal GA accidents between 2001 and 2010, it was concluded that over half of the fatal accidents were a result of loss of control inflight, or LOC-I.

• A Loss of Control Working Group (LOCWG) was formed between the FAA and the GA industry to research and recommend safety improvements. …

Basic Number Sysyems, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Basic Number Systems" from January 14, 2014.

Sse-122 Satellites & Space Systems, Spring 2014, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A syllabus created by Professor Bob Twiggs for Space Science Engineering - Satellites & Space Systems (SSE 122) on January 14, 2014.

Rapid Space Trajectory Generation Using A Fourier Series Shape-Based Approach, Ehsan Taheri

Dissertations, Master's Theses and Master's Reports - Open

With the insatiable curiosity of human beings to explore the universe and our solar system, it is essential to benefit from larger propulsion capabilities to execute efficient transfers and carry more scientific equipment. In the field of space trajectory optimization the fundamental advances in using low-thrust propulsion and exploiting the multi-body dynamics has played pivotal role in designing efficient space mission trajectories. The former provides larger cumulative momentum change in comparison with the conventional chemical propulsion whereas the latter results in almost ballistic trajectories with negligible amount of propellant. However, the problem of space trajectory design translates into an optimal …

Development Of An Ionic Liquid Ferrofluid Electrospray Source And Mode Shape Studies Of A Ferrofluid In A Non-Uniform Magnetic Field, Edmond Joseph Meyer Iv

Dissertations, Master's Theses and Master's Reports - Open

An electrospray source has been developed using a novel new fluid that is both magnetic and conductive. Unlike conventional electrospray sources that required microfabricated structures to support the fluid to be electrosprayed, this new electrospray fluid utilizes the Rosensweig instability to create the structures in the magnetic fluid when an external magnetic field was applied. Application of an external electric field caused these magnetic fluid structures to spray. These fluid based structures were found to spray at a lower onset voltage than was predicted for electrospray sources with solid structures of similar geometry. These fluid based structures were also found …

Experimental And Numerical Study Of Carbon Fiber Oxidation, Francesco Panerai, Nagi N. Mansour, Jean Lachaud, Alexandre Martin

Mechanical Engineering Faculty Publications

The oxidation at high Knudsen number of FiberForm® , the matrix material of NASA's Phenolic Impregnated Carbon Ablator, is investigated both experimentally and numerically. The experimental setup consists of a quartz tube through a clamshell heater. Mass loss and recession of carbon preform samples are measured at temperatures between 700 and 1300 K and pressures around 2000 Pa. A volume average fiber-scale oxidation model is used to model the setup and extract the effective reactivity of the material. New values for carbon fiber reactivity are suggested and discussed.

Landsat-8: Science And Product Vision For Terrestrial Global Change Research, David P. Roy, M. A. Wulder, T. R. Loveland, C. E. Woodcock, R. G. Allen, M. C. Anderson, D. Helder, J. R. Irons, D. M. Johnson, R. Kennedy, T. A. Scambos, C. B. Schaaf, J. R. Schott, Y. Sheng, E. F. Vermote, A. S. Belward, R. Bindschadler, W. B. Cohen, F. Gao, J. D. Hipple, P. Hostert, Desert Research Institute, Reno, Nv, C. O. Justice, Ayse Kilic, V. Kovalskyy, Z. P. Lee, L. Lymburner, J. G. Masek, J. Mccorkel, Y. Shuai, R. Trezza, J. Vogelmann, R. H. Wynne, Z. Zhu

School of Natural Resources: Faculty Publications

Landsat 8, a NASA and USGS collaboration, acquires global moderate-resolution measurements of the Earth's terrestrial and polar regions in the visible, near-infrared, short wave, and thermal infrared. Landsat 8 extends the remarkable 40 year Landsat record and has enhanced capabilities including new spectral bands in the blue and cirrus cloud-detection portion of the spectrum, two thermal bands, improved sensor signal-to-noise performance and associated improvements in radiometric resolution, and an improved duty cycle that allows collection of a significantly greater number of images per day. This paper introduces the current (2012–2017) Landsat Science Team's efforts to establish an initial understanding of …

Estimation Of Crop Gross Primary Production (Gpp): FaparChl Versus Mod15a2 Fpar, Qingyuan Zhang, Yen-Ben Cheng, A. I. Lyapustin, Yujie Wang, Feng Gao, Andrew E. Suyker, Shashi B. Verma, Elizabeth M. Middleton

School of Natural Resources: Faculty Publications

Photosynthesis (PSN) is a pigment level process in which antenna pigments (predominately chlorophylls) in chloroplasts absorb photosynthetically active radiation (PAR) for the photochemical process. PAR absorbed by foliar non-photosynthetic components is not used for PSN. The fraction of PAR absorbed (fAPAR) by a canopy/vegetation (i.e., fAPAR_canopy) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) images, referred to as MOD15A2 FPAR, has been used to compute absorbed PAR (APAR) for PSN (APAR_PSN) which is utilized to produce the standard MODIS gross primary production (GPP) product, referred to as MOD17A2 GPP. In this study, the fraction of PAR …

Evolution Of Perturbations In Flow Field Mechanics, Samantha R. Bell, David Forliti, Nils Sedano, Kriss Vanderhyde

STAR Program Research Presentations

This project explores the stability analysis of a given flow field. Specifically, where the peak disturbance occurs in a flow as this is the disturbance that is most likely to occur. In rocket combustion, it is important to understand where the maximum disturbance occurs so that the mixing of fuel can be stabilized. The instabilities are the results of frequencies in the area surrounding the flow field. The linear stability governing equations are employed to better understand the disturbance. The governing equations for continuity and momentum in the x and y directions are used to form an equation for the …

State-Space Representation Of The Unsteady Aerodynamics Of Flapping Flight, Haithem E. Taha, Muhammad R. Hajj, Philip S. Beran

United States Air Force: Publications

A state-space formulation for the aerodynamics of flapping flight is presented. The Duhamel's principle, applied in linear unsteady flows, is extended to non-conventional lift curves to capture the LEV contribution. The aspect ratio effects on the empirical formulae used to predict the static lift due to a stabilized Leading Edge Vortex (LEV) are provided. The unsteady lift due to arbitrary wing motion is generated using the static lift curve. Then, state-space representation for the unsteady lift is derived. The proposed model is validated through a comparison with direct numerical simulations of Navier-Stokes on hovering insects. A comparison with quasi-steady models …

High-Efficiency Thrust Vector Control Allocation, Jeb S. Orr, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

A generalized approach to the allocation of redundant thrust vector slew commands for multi-actuated launch vehicles is presented, where deflection constraints are expressed as omniaxial or elliptical deflection limits in gimbal axes. More importantly than in the aircraft control allocation problem, linear allocators (pseudoinverses) are preferred for large booster applications to facilitate accurate prediction of the control-structure interaction resulting from thrust vectoring effects. However, strictly linear transformations for the allocation of redundant controls cannot, in general, access all of the attainable moments for which there is a set of control effector positions thatsatisfles the constraints. In this paper, the control …

Gust Mitigation Of Micro Air Vehicles Using Passive Articulated Wings, Adetunji Oduyela, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Birds and insects naturally use passive flexing of their wings to augment their stability in uncertain aerodynamic environments. In a similar manner, micro air vehicle designers have been investigating using wing articulation to take advantage of this phenomenon. The result is a class of articulated micro air vehicles where artificial passive joints are designed into the lifting surfaces. In order to analyze how passive articulation affects performance of micro air vehicles in gusty environments, an efficient 8 degree-of-freedom model is developed. Experimental validation of the proposed mathematical model was accomplished using flight test data of an articulated micro air vehicle …

A Mobile Self-Leveling Landing Platform For Small-Scale Uavs, Stephen Austin Conyers

Electronic Theses and Dissertations

This thesis presents a semi-autonomous mobile self-leveling landing platform designed to launch, recover and re-launch VTOL UAVs without the need for human intervention. The landing platform is rugged, lightweight and inexpensive, making it ideal for civilian applications that require a base station from which a rotorcraft UAV can be launched and recovered on terrain that is normally unsuitable for UAV operations. This landing platform is capable of self-leveling on rough terrain and inclined slopes, and can autonomously operate in remote locations for extended periods of time using large onboard lithium batteries and wireless communication. This thesis discusses the unique design …