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Air Force Institute of Technology

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Articles 1351 - 1380 of 3057

Full-Text Articles in Physical Sciences and Mathematics

M + Ng Potential Energy Curves Including Spin-Orbit Coupling For M = K, Rb, Cs And Ng = He, Ne, Ar, Larry Aaron Blank, David E. Weeks, Gary S. Kedziora Mar 2012

M + Ng Potential Energy Curves Including Spin-Orbit Coupling For M = K, Rb, Cs And Ng = He, Ne, Ar, Larry Aaron Blank, David E. Weeks, Gary S. Kedziora

Faculty Publications

X2Σ+1/2 ⁠, A2Π1/2, A2Π3/2, and B2Σ+1/2 potential energy curves and associated dipole matrix elements are computed for M + Ng at the spin-orbit multi-reference configuration interaction level, where M = K, Rb, Cs and Ng = He, Ne, Ar. Dissociation energies and equilibrium positions for all minima are identified and corresponding vibrational energy levels are computed. Difference potentials are used together with the quasistatic approximation to estimate the position of satellite peaks of collisionally broadened D2 lines. The comparison of potential energy curves for …

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Remote Sensing Phase Fluorimetry Using Mercury Vapor Lamp, Matthew J. Bohn, Michael A. Lundin Mar 2012

Remote Sensing Phase Fluorimetry Using Mercury Vapor Lamp, Matthew J. Bohn, Michael A. Lundin

AFIT Patents

An efficient and portable method for remote detection of a target mineral material through frequency domain fluorimetry, a detection technique that measures the time lag between absorption and emission of photons, thereby determining the lifetime of said target mineral material. As claimed and disclosed in the present invention, mercury vapor lamps, a common source of industrial facility lighting, emit radiation that overlaps the UV/blue absorption spectrum of many fluorophores and may be used as an efficient and portable excitation source for remote frequency domain fluorimetry.

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Electro-Luminescent Display Device, Michael E. Miller, Joseph R. Bietry, Ronald S. Cok Mar 2012

Electro-Luminescent Display Device, Michael E. Miller, Joseph R. Bietry, Ronald S. Cok

AFIT Patents

An electro-luminescent display includes a first array of light-emitting elements. Each of these light-emitting elements has an optical element. A second array of light-emitting elements also includes a second optical element different from the first. One or more row lines are electrically connected to either light-emitting elements in the first array of light-emitting elements or light-emitting elements in the second array of light-emitting elements. One or more column lines provide a data signal to the first and second array of light-emitting elements. A driver circuit delivers common information to the light-emitting elements in both the first and second arrays in …

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Spatial And Spectral Performance Of A Chromotomosynthetic Hyperspectral Imaging System, Randall L. Bostick, Glen P. Perram Mar 2012

Spatial And Spectral Performance Of A Chromotomosynthetic Hyperspectral Imaging System, Randall L. Bostick, Glen P. Perram

Faculty Publications

The spatial and spectral resolutions achievable by a prototype rotating prism chromotomosynthetic imaging (CTI) system operating in the visible spectrum are described. The instrument creates hyperspectral imagery by collecting a set of 2D images with each spectrally projected at a different rotation angle of the prism. Mathematical reconstruction techniques that have been well tested in the field of medical physics are used to reconstruct the data to produce the 3D hyperspectral image. The instrument operates with a 100 mm focusing lens in the spectral range of 400–900 nm with a field of view of 71.6 mrad and angular resolution of …

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Comparative Analysis Of Two Biological Warfare Air Samplers Using Live Surrogate Agents, James C. Enderby Mar 2012

Comparative Analysis Of Two Biological Warfare Air Samplers Using Live Surrogate Agents, James C. Enderby

Theses and Dissertations

The United States Air Force has several high-volume biological air samplers, including the XMX/2L-MIL and the Biocapture 650. Limited information is available on either in terms of its collection of viruses and bacteria. However, previous research on the XMX/2L-MIL has determined that modifications to the secondary flow rate and the use of a virus preserving collection media may provide improved virus collection rates. In this thesis, these modifications were investigated to determine their impact on the collection of viral and bacterial aerosols. Additionally, relative collection rates were compared against those for the Biocapture 650. MS2 bacteriophage was the viral surrogate …

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Security Standards And Best Practice Considerations For Quantum Key Distribution (Qkd), Carole A. Harper Mar 2012

Security Standards And Best Practice Considerations For Quantum Key Distribution (Qkd), Carole A. Harper

Theses and Dissertations

Quantum Key Distribution (QKD) systems combine cryptographic primitives with quantum information theory to produce a theoretic unconditionally secure cryptographic key. However, real-world implementations of QKD systems are far from ideal and differ significantly from the theoretic model. Because of this, real-world QKD systems require additional practical considerations when implemented to achieve secure operations. In this thesis, a content analysis of the published literature is conducted to determine if established security and cryptographic standards and best practices are addressed in real world, practical QKD implementations. The research reveals that most published, real world QKD implementations do not take advantage of established …

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Optimization Of Nanoscale Zero-Valent Iron For The Remediation Of Groundwater Contaminants, Andrew W. E. Mcpherson Mar 2012

Optimization Of Nanoscale Zero-Valent Iron For The Remediation Of Groundwater Contaminants, Andrew W. E. Mcpherson

Theses and Dissertations

Nanoscale zero-valent iron (nZVI) is an emerging tool for the remediation of groundwater contaminants. The nanoparticles are capable of reductively destroying or immobilizing a wide range of contaminants. Their small size results in a high surface area to mass ratio, making them much more reactive compared to their more-coarse predecessors. Small particle size also allows nZVI particles to be injected directly into contaminated areas via a well, limiting the above-ground footprint and allowing access to contaminated areas that are beyond the reach of some conventional methods. nZVI technology has the potential to facilitate remediation in difficult situations, improve remediation outcomes, …

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Analysis Of The Impact Of Data Normalization On Cyber Event Correlation Query Performance, Smile T. Ludovice Mar 2012

Analysis Of The Impact Of Data Normalization On Cyber Event Correlation Query Performance, Smile T. Ludovice

Theses and Dissertations

A critical capability required in the operation of cyberspace is the ability to maintain situational awareness of the status of the infrastructure elements that constitute cyberspace. Event logs from cyber devices can yield significant information, and when properly utilized they can provide timely situational awareness about the state of the cyber infrastructure. In addition, proper Information Assurance requires the validation and verification of the integrity of results generated by a commercial log analysis tool. Event log analysis can be performed using relational databases. To enhance database query performance, previous literatures affirm denormalization of databases. Yet database normalization can also increase …

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Modeling The Impact Of Cracking In Low Permeability Layers In A Groundwater Contamination Source Zone On Dissolved Contamination Source Zone On Dissolved Contaminant Fate And Transport, Katherine W. Sievers Mar 2012

Modeling The Impact Of Cracking In Low Permeability Layers In A Groundwater Contamination Source Zone On Dissolved Contamination Source Zone On Dissolved Contaminant Fate And Transport, Katherine W. Sievers

Theses and Dissertations

The storage and transport of a dense non-aqueous phase liquid (DNAPL) was evaluated using a numerical model. Many DNAPLs are used as solvents by the DoD and industry. The improper disposal and handling of these chemicals has led to long term contamination of groundwater. When spilled, a DNAPL will pool atop low permeability layers and slowly dissolve creating a contaminant plume. The dissolved contaminant within a low permeability layer serves as long-term sources of contamination once the source is removed. In this study, cracks are hypothesized to exist in the low permeability layers, allowing for enhanced transport. A numerical model …

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Analysis Of Leadership In Energy And Environmental Design® Construction In The Air Force, James M. Rozzoni Mar 2012

Analysis Of Leadership In Energy And Environmental Design® Construction In The Air Force, James M. Rozzoni

Theses and Dissertations

The Air Force uses the Leadership in Energy and Environmental Design (LEED) rating system as a third party verification system to ensure sustainable and resource-conscious facilities. The Federal Government has implemented several mandates in recent years that require certain milestones be met for energy reduction, water conservation, renewable energy use, and so forth. This research aims to determine how the Air Force has implemented LEED through credit analysis, and to better understand why LEED is being used in this way. Using a database of 172 military construction projects, the research evaluates the frequency of credit usage individually and by category. …

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Emissions From Simulated Open Burning Of Deployed Us Military Waste, Brian D. Woodall Mar 2012

Emissions From Simulated Open Burning Of Deployed Us Military Waste, Brian D. Woodall

Theses and Dissertations

U.S. military forces have relied primarily on open burning as an expedient method of volume reduction and treatment of solid waste during the conflicts in Afghanistan and Iraq. This study is the first effort to characterize a broad range of pollutants and their emission factors during the burning of military waste and the effects that recycling efforts, namely removing plastics, might have on emissions. Piles of simulated military waste were constructed, burned, and emissions sampled at the U.S. Environmental Protection Agency (EPA) Open Burn Testing Facility (OBTF), Research Triangle Park, NC. Three tests contained polyethylene terephthalate (PET #1 or PET) …

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Magnesium Object Manager Sandbox, A More Effective Sandbox Method For Windows 7, Martin A. Gilligan Mar 2012

Magnesium Object Manager Sandbox, A More Effective Sandbox Method For Windows 7, Martin A. Gilligan

Theses and Dissertations

A major issue in computer security is limiting the affects a program can have on a computer. One way is to place the program into a sandbox, a limited environment. Many attempts have been made to create a sandbox that maintains the usability of a program and effectively limits the effects of the program. Sandboxes that limit the resources programs can access, have succeeded. To test the effectiveness of a sandbox that limits the resources a program can access on Windows 7, the Magnesium Object Manager Sandbox (MOMS) is created. MOMS uses a kernel mode Windows component to monitor and …

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Scalable Wavelet-Based Active Network Stepping Stone Detection, Joseph I. Gilbert Mar 2012

Scalable Wavelet-Based Active Network Stepping Stone Detection, Joseph I. Gilbert

Theses and Dissertations

Network intrusions leverage vulnerable hosts as stepping stones to penetrate deeper into a network and mask malicious actions from detection. This research focuses on a novel active watermark technique using Discrete Wavelet Transformations to mark and detect interactive network sessions. This technique is scalable, nearly invisible and resilient to multi-flow attacks. The watermark is simulated using extracted timestamps from the CAIDA 2009 dataset and replicated in a live environment. The simulation results demonstrate that the technique accurately detects the presence of a watermark at a 5% False Positive and False Negative rate for both the extracted timestamps as well as …

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An Analysis Of Error Reconciliation Protocols For Use In Quantum Key Distribution, James S. Johnson Mar 2012

An Analysis Of Error Reconciliation Protocols For Use In Quantum Key Distribution, James S. Johnson

Theses and Dissertations

Quantum Key Distribution (QKD) is a method for transmitting a cryptographic key between a sender and receiver in a theoretically unconditionally secure way. Unfortunately, the present state of technology prohibits the flawless quantum transmission required to make QKD a reality. For this reason, error reconciliation protocols have been developed which preserve security while allowing a sender and receiver to reconcile the errors in their respective keys. The most famous of these protocols is Brassard and Salvail's Cascade, which is effective, but suffers from a high communication complexity and therefore results in low throughput. Another popular option is Buttler's Winnow protocol, …

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Evaluation Of Malware Target Recognition Deployed In A Cloud-Based Fileserver Environment, G. Parks Masters Mar 2012

Evaluation Of Malware Target Recognition Deployed In A Cloud-Based Fileserver Environment, G. Parks Masters

Theses and Dissertations

Cloud computing, or the migration of computing resources from the end user to remotely managed locations where they can be purchased on-demand, presents several new and unique security challenges. One of these challenges is how to efficiently detect malware amongst files that are possibly spread across multiple locations in the Internet over congested network connections. This research studies how such an environment will impact the performance of malware detection. A simplified cloud environment is created in which network conditions are fully controlled. This environment includes a fileserver, a detection server, the detection mechanism, and clean and malicious file sample sets. …

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Evaluation Of Traditional Security Solutions In The Scada Environment, Robert D. Larkin Mar 2012

Evaluation Of Traditional Security Solutions In The Scada Environment, Robert D. Larkin

Theses and Dissertations

Supervisory Control and Data Acquisition (SCADA) systems control and monitor the electric power grid, water treatment facilities, oil and gas pipelines, railways, and other Critical Infrastructure (CI). In recent years, organizations that own and operate these systems have increasingly interconnected them with their enterprise network to take advantage of cost savings and operational benefits. This trend, however, has introduced myriad vulnerabilities associated with the networking environment. As a result, the once isolated systems are now susceptible to a wide range of threats that previously did not exist. To help address the associated risks, security professionals seek to incorporate mitigation solutions …

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Collisional Dynamics, Lasing And Stimulated Raman Scattering In Optically Pumped Cesium And Potassium Vapors, Kirk C. Brown Mar 2012

Collisional Dynamics, Lasing And Stimulated Raman Scattering In Optically Pumped Cesium And Potassium Vapors, Kirk C. Brown

Theses and Dissertations

This dissertation explores collisional dynamics, lasing and stimulated Raman scattering in cesium and potassium vapors. The spin orbit mixing and quenching cross sections of several buffer gas species are measured. The ne-structure mixing cross sections for He, CH4 and C2H6 are 14±3, 35±6 and 73±10 °A2, respectively. The 2P3/2 state is quenched more rapidly than the 2P1/2 state. A pulsed blue laser operating via direct excitation of the cesium 72P3/2 state is demonstrated. A theoretical model is extended and compared with experimental results. The maximum output …

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Positron Lifetime Modulation By Electric Field Induced Positronium Formation On A Gold Surface, Daniel J. Higgins Mar 2012

Positron Lifetime Modulation By Electric Field Induced Positronium Formation On A Gold Surface, Daniel J. Higgins

Theses and Dissertations

The purpose of this project is to study the lifetime and annihilation mode of positrons, the antimatter counterpart to electrons, and the formation rate of positronium on a gold surface modified by gold nanoparticles under the influence of radial electric fields measured using two independent systems. The positron annihilation photon pair/triplet spectroscopy system uses a sodium iodide ring detector segmented into six detection regions providing rough position sensitivity to measure the ratio of two to three photon positron annihilation events. An increased rate of three photon annihilation events and a decreased rate of two photon annihilation events are observed when …

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Matrix Determination Of Reflectivity Of Hidden Object Via Indirect Photography, Simon S. Ferrel Mar 2012

Matrix Determination Of Reflectivity Of Hidden Object Via Indirect Photography, Simon S. Ferrel

Theses and Dissertations

Indirect photography is a recently demonstrated technique which expands on the principles of dual photography and allows for the imaging of hidden objects. A camera and light source are collocated with neither having line-of-sight access to the hidden object. Light from the source, a laser, is reflected off a visible non-specular surface onto the hidden object, where it is reflected back to the initial non-specular surface and collected by the camera. This process may be repeated numerous times for various laser spot positions to yield slightly different camera images due to a variation in the illumination of the object. These …

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Electrical And Optical Characterization Of Si-Ge-Sn, Merle D. Hamilton Mar 2012

Electrical And Optical Characterization Of Si-Ge-Sn, Merle D. Hamilton

Theses and Dissertations

The electrical characterization of boron-doped p-Si0.08Ge0.90Sn0.02/p-Ge(100) and p-Si0.112Ge0.86Sn0.028/n-Si(100) with various epilayer thicknesses was measured using the Hall effect. The room temperature sheet carrier concentration ranged from 1.21 x 1013 – 1.32 x 1016 cm-2. The room temperature mobilities were measured to be between 166 and 717 cm2/V·s, depending on sample composition. In the low temperature regime, the mobility was mainly affected by ionized impurity scattering. In the high temperature regime, the mobility was mainly affected by …

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Comparative Statistical Analysis Of Auroral Models, Cory T. Lane Mar 2012

Comparative Statistical Analysis Of Auroral Models, Cory T. Lane

Theses and Dissertations

The location of the equatorward boundary of the auroral oval provides an appropriate means to measure the accuracy of auroral models. In this study, the equatorward boundary is represented by the location at which the energy flux data measured by DMSP satellites exceeds 0.4 erg/cm2/s. The MLAT coordinates obtained from more than 4,000 orbits through the polar region of the Northern Hemisphere comprise the data set used to compare to the outputs of five auroral models. These models are: the original Hardy auroral model of 1985 (OH), the OVATION Prime model (OP), the 2008 adaptation to the Hardy …

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Durability Of Mwcnt Composites Under Electron And Neutron Irradiation, Quan-Hai T. Lu Mar 2012

Durability Of Mwcnt Composites Under Electron And Neutron Irradiation, Quan-Hai T. Lu

Theses and Dissertations

Electromagnetic interference shielding effectiveness and conductive properties of carbon nanotube containing composites intended for use as satellite surface materials have been investigated following electron and neutron irradiation. The MWCNT composites were irradiated to fluence levels of 1016 electrons/cm2 with 500 keV electrons. Increase in EMI-SE and conductivity was observed following electron irradiation in two of the samples. The sample with alternating layers of MWCNT and glass had a decrease in conductivity and an increase in EMI-SE post irradiation. This would suggest that the different layered configuration does play a role in the durability of the composite. Having multiple …

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Design And Characterization Of A Three-Dimensional Positron Annihilation Spectroscopy System Using A Low-Energy Positron Beam, Stephen M. Jimenez Mar 2012

Design And Characterization Of A Three-Dimensional Positron Annihilation Spectroscopy System Using A Low-Energy Positron Beam, Stephen M. Jimenez

Theses and Dissertations

Previous forays by AFIT into positron research have resulted in the development of a new positron annihilation spectroscopy (PAS) technique and the procurement of a low-energy positron beam system. The primary purpose of this research was to design and build a state-of-the-art PAS laboratory at AFIT capable to address a myriad of DoD solid-state and surface physics questions. The main objectives were to acquire and assemble utilities to operate a positron beam, assemble and configure an ultra-high vacuum (UHV) system for samples, design and build an interface with a magnetic field to propagate positrons onto samples, and create a new …

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Neutron Detection Using Amorphous Boron-Carbide Hetero-Junction Diodes, Thomas P. Mcquary Mar 2012

Neutron Detection Using Amorphous Boron-Carbide Hetero-Junction Diodes, Thomas P. Mcquary

Theses and Dissertations

The high energy products of the 10B(n,α)7Li neutron capture reaction were explored as a means of thermal neutron detection in thin film amorphous boron carbide (a--B5C:Hx) on n-type silicon hetero-junction diodes. Pulse height spectroscopy was conducted on the diodes while they were subjected to a moderated plutonium-beryllium (PuBe) source. Neutron capture could not be confirmed experimentally in any of the devices tested. Device modeling was performed to investigate the cause for the diode detector's negative response. A 1.47 MeV α particle produced transient current of 10-7 A and the induced was 4.7 …

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Cesium Absorption Spectrum Perturbed By Argon: Observation Of Non-Lorentzian Far Wings, Gordon E. Lott Mar 2012

Cesium Absorption Spectrum Perturbed By Argon: Observation Of Non-Lorentzian Far Wings, Gordon E. Lott

Theses and Dissertations

The purpose of this research was to observe the core and far wing absorption spectra of the D1 and D2 lines of cesium (Cs) perturbed by argon (Ar). A 1.33 m scanning monochromator with a PMT detector was used to measure the spectra from 8300 Å to 9100 Å. A heat pipe was used to control the Cs concentration and Ar pressure allowing for a broad range of spectra to be collected. Spectra were collected for heat pipe temperatures of 50, 75, 100, 125, 150 and 175 °C, corresponding to Cs concentrations of approximately 6×1011, 4×10 …

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The Focusing Of Light Scattered From Diffuse Reflectors Using Phase Modulation, Jessica M. Schafer Mar 2012

The Focusing Of Light Scattered From Diffuse Reflectors Using Phase Modulation, Jessica M. Schafer

Theses and Dissertations

“Indirect photography" was recently demonstrated for imaging hidden scene information through the collection and radiometric modeling of light reflecting off of visible reflecting surfaces. The ability to focus the beam that reflects off the visible surface to a tight spot on the hidden object is theorized to simulate a direct line of sight from the light source to the object, reducing the radiometric model to that of the previously demonstrated dual photography. Experiments involving the focusing of light transmitted through highly scattering media have been adapted to the case of reflection. The focusing of a HeNe laser reflected off diffusely …

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Characterization Of A Hyperspectral Chromotomographic Imaging Ground System, Chad B. Su'e Mar 2012

Characterization Of A Hyperspectral Chromotomographic Imaging Ground System, Chad B. Su'e

Theses and Dissertations

A field-deployable hyperspectral chromotomographic imager has been developed and tested as a risk-reduction prototype to assist design of a space-based system. The instrument uses a high-speed video camera looking through a rotating direct-vision prism to simultaneously observe the full field of view in all visible wavelength channels. The chromotomographic process multiplexes the spectral and spatial so an advanced reconstruction algorithm is required to separate the spectral channels. A physics-based model of the instrument was developed to assist in future trade-space choices for design of the spaced-based system. Additionally, the model is used for the development and assessment of the filtered …

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Spectral And Spatial Coherent Emission Of Thermal Radiation From Metal-Semiconductor Nanostructures, Shane N. Mcconnell Mar 2012

Spectral And Spatial Coherent Emission Of Thermal Radiation From Metal-Semiconductor Nanostructures, Shane N. Mcconnell

Theses and Dissertations

The spectral and spatial radiative properties of coherent thermal emission in the mid- and far-IR through the use of micro and nano-structured metal-semiconductor materials were designed and demonstrated experimentally. Using an implementation of the Rigorous Coupled Wave Analysis and Computer Simulation Technology (CST), two structures were designed to selectively emit at mid- and far-IR wavelengths, a 1-D truncated multilayer resonator and a 3-D hybrid photonic crystal (PC)-multilayer. A High Impulse Power Magnetron Sputtering (HIPIMS) deposition technique was used to fabricate two silver-germanium-silver (Ag-Ge-Ag) resonating structures with layer thicknesses of 6-240-160 nm for one sample and 6-700-200 nm for the other. …

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Security Verification Of Secure Manet Routing Protocols, Matthew F. Steele Mar 2012

Security Verification Of Secure Manet Routing Protocols, Matthew F. Steele

Theses and Dissertations

Secure mobile ad hoc network (MANET) routing protocols are not tested thoroughly against their security properties. Previous research focuses on verifying secure, reactive, accumulation-based routing protocols. An improved methodology and framework for secure MANET routing protocol verification is proposed which includes table-based and proactive protocols. The model checker, SPIN, is selected as the core of the secure MANET verification framework. Security is defined by both accuracy and availability: a protocol forms accurate routes and these routes are always accurate. The framework enables exhaustive verification of protocols and results in a counter-example if the protocol is deemed insecure. The framework is …

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A Black Hole Attack Model For Reactive Ad-Hoc Protocols, Christopher W. Badenhop Mar 2012

A Black Hole Attack Model For Reactive Ad-Hoc Protocols, Christopher W. Badenhop

Theses and Dissertations

Net-Centric Warfare places the network in the center of all operations, making it a critical resource to attack and defend during wartime. This thesis examines one particular network attack, the Black Hole attack, to determine if an analytical model can be used to predict the impact of this attack on ad-hoc networks. An analytical Black Hole attack model is developed for reactive ad-hoc network protocols DSR and AODV. To simplify topology analysis, a hypercube topology is used to approximate ad-hoc topologies that have the same average node degree. An experiment is conducted to compare the predicted results of the analytical …

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