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Air Force Institute of Technology

Faculty Publications

2011

Articles 1 - 12 of 12

Full-Text Articles in Engineering

Jet Propellant 8 Versus Alternative Jet Fuels, Peter Feng, Wayne C. Kinsel, Alfred E. Thal Jr., Charles A. Bleckmann Jul 2011

Jet Propellant 8 Versus Alternative Jet Fuels, Peter Feng, Wayne C. Kinsel, Alfred E. Thal Jr., Charles A. Bleckmann

Faculty Publications

The Air Force is the largest user of jet fuel in the Department of Defense DOD, consuming 2.4 billion gallons per year. In light of environmental impacts associated with using nonrenewable fuel sources and national security concerns regarding dependency on foreign oil, it is no surprise that the United States is paying more attention to alternative fuels. Both DOD and Air Force energy strategies address the need to develop and produce such fuels. The DOD has made a commitment to energy security, establishing an energy initiative that strives to modernize infrastructure, increase utility and energy conservation, enhance demand reduction, and …

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Unintended Consequences: Potential Downsides Of The Air Force's Conversion To Biofuels, Mark N. Goltz, Charles A. Bleckmann, Charles M. Mackay, Khai Vuong, Jerrod P. Mccomb Jul 2011

Unintended Consequences: Potential Downsides Of The Air Force's Conversion To Biofuels, Mark N. Goltz, Charles A. Bleckmann, Charles M. Mackay, Khai Vuong, Jerrod P. Mccomb

Faculty Publications

The desire to reduce US dependence on foreign energy, ongoing environmental concerns, and the rising cost of petroleum have sparked significant development of greener alternative and renewable energy sources such as alcohol-based biofuels. To address these issues, the Department of Defense DOD has moved to diminish its reliance on petroleum for fueling aircraft and ground equipment. The US Air Force, in alignment with DOD objectives, has initiated several goals for reducing its use of energy: (1) decrease the use of petroleum-based fuel by 2 percent annually for the vehicle fleet, (2) increase the use of alternative fuel in motor vehicles …

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Using Nanotechnology To Detect Nerve Agents, Mark N. Goltz, Dong-Shik Kim, Leeann Racz Jul 2011

Using Nanotechnology To Detect Nerve Agents, Mark N. Goltz, Dong-Shik Kim, Leeann Racz

Faculty Publications

Nanotechnology has opened a wide range of opportunities having potential impacts in areas as diverse as medicine and consumer products. In collaboration with researchers at the University of Toledo UT, Air Force Institute of Technology AFIT scientists are exploring the possibility of using a nanoscale organic matrix to detect organophosphate OP nerve agents. Current techniques for detecting OP compounds are expensive and time consuming. Developing a nanoscale organic matrix sensor would allow for direct, real-time sensing under field conditions. This article describes the science behind such a sensor and its possible applications. High-performance sensors are needed to protect Soldiers and …

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Aerospike Rockets For Increased Space Launch Capability, Carl R. Hartsfield, Richard D. Branam, Joshua N. Hall, Joseph R. Simmons Iii Jul 2011

Aerospike Rockets For Increased Space Launch Capability, Carl R. Hartsfield, Richard D. Branam, Joshua N. Hall, Joseph R. Simmons Iii

Faculty Publications

No abstract provided.

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X-Hale: Designing The Atmospheric Surveillance Platforms Of The Future, Christopher M. Shearer Jul 2011

X-Hale: Designing The Atmospheric Surveillance Platforms Of The Future, Christopher M. Shearer

Faculty Publications

Imagine the benefits that battlefield commanders or intelligence analysts could derive from an airborne surveillance platform that would carry a 500-pound payload, operate above the range of small arms fire, remain on station for weeks or even years, cost much less than a satellite, and relocate around the globe to a new region of interest within a couple of weeks. Realizing this concept, known as a high-altitude, long-endurance HALE aircraft, is a 10-to-15-year goal of researchers at the Air Force Institute of Technology AFIT. In order to reach this goal, those researchers are following a developmental path similar to the …

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A Taskable Space Vehicle: Realizing Cost Savings By Combining Orbital And Suborbital Flight, Thomas Co, Jonathan T. Black Jul 2011

A Taskable Space Vehicle: Realizing Cost Savings By Combining Orbital And Suborbital Flight, Thomas Co, Jonathan T. Black

Faculty Publications

The use of space gives the United States distinct advantages in any battlefield environment, but the high cost of space operations increasingly jeopardizes those advantages. Although the United States pioneered much of the current space technology, declining budgets for space research, development, and operations leave our legacy systems vulnerable to adversaries around the world. Other nations formerly incapable of space exploitation are quickly learning to counter US space technologies at surprisingly low costs. In order to reduce the expense of deploying and maintaining a robust space capability, the Department of Defense (DOD) must change the status quo in space operations …

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Achieving The Air Force’S Energy Vision, Frederick G. Harmon, Richard D. Branam, Doral E. Sandlin Jul 2011

Achieving The Air Force’S Energy Vision, Frederick G. Harmon, Richard D. Branam, Doral E. Sandlin

Faculty Publications

The US Air Force is the largest consumer of energy in the federal government, spending 9 billion in 2008 to fuel aircraft and ground vehicles as well as provide energy to installations.1 In that same year, the Air Force s fuel bill of 7 billion amounted to more than half of the US government s total fuel cost.2 Because of the critical and central role that energy plays in completion of the Air Force’s mission, the secretary of the Air Force has developed an Air Force energy plan supported by three pillars Reduce Demand, Increase Supply, and Culture …

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Precision Position, Navigation, And Timing Without The Global Positioning System, Kenneth A. Fisher, John F. Raquet Jul 2011

Precision Position, Navigation, And Timing Without The Global Positioning System, Kenneth A. Fisher, John F. Raquet

Faculty Publications

The NAVSTAR Global Positioning System GPS has revolutionized modern warfare. Since 2005 almost all US precision-guided munitions have used GPS targeting data. Consequently, weapons delivery systems are able to strike enemy targets with precision, often resulting in little or no collateral damage. Furthermore, nearly all military assets, including aircraft, tanks, ships, missiles, mortar rounds, cargo boxes, and dismounted Soldiers rely on the accurate position determination that GPS provides. For military users of this system, two main limitations emerge. First, the system relies on line of sight that is, the satellites must be in view of the receiver s antenna so …

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Wolf Ant, Gilbert L. Peterson, Christopher M. Mayer, Kevin Cousin Jun 2011

Wolf Ant, Gilbert L. Peterson, Christopher M. Mayer, Kevin Cousin

Faculty Publications

Ant colony optimization (ACO) algorithms can generate quality solutions to combinatorial optimization problems. However, like many stochastic algorithms, the quality of solutions worsen as problem sizes grow. In an effort to increase performance, we added the variable step size off-policy hill-climbing algorithm called PDWoLF (Policy Dynamics Win or Learn Fast) to several ant colony algorithms: Ant System, Ant Colony System, Elitist-Ant System, Rank-based Ant System, and Max-Min Ant System. Easily integrated into each ACO algorithm, the PDWoLF component maintains a set of policies separate from the ant colony's pheromone. Similar to pheromone but with different update rules, the PDWoLF policies …

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Ir Nonlinear Absorption Leading To Laser-Induced Damage In Ge & Gasb, Torrey J. Wagner, Matthew J. Bohn, Ronald A. Coutu Jr., L. P. Gonzales, J. M. Murray, K. L. Schepler, S. Guha Jun 2011

Ir Nonlinear Absorption Leading To Laser-Induced Damage In Ge & Gasb, Torrey J. Wagner, Matthew J. Bohn, Ronald A. Coutu Jr., L. P. Gonzales, J. M. Murray, K. L. Schepler, S. Guha

Faculty Publications

Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 μm for the first time. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 μm and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al2O3 anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for ps or ns pulses, respectively. Wavelength-dependant …

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Complementary Metal-Oxide Semiconductor-Compatible Detector Materials With Enhanced 1550 Nm Responsivity Via Sn-Doping Of Ge/Si(100), Richard T. Beeler, Jay Mathews, Mee-Yi Ryu, Yung-Kee Yeo, Jose Menendez, John Kouvetakis May 2011

Complementary Metal-Oxide Semiconductor-Compatible Detector Materials With Enhanced 1550 Nm Responsivity Via Sn-Doping Of Ge/Si(100), Richard T. Beeler, Jay Mathews, Mee-Yi Ryu, Yung-Kee Yeo, Jose Menendez, John Kouvetakis

Faculty Publications

Previously developed methods used to grow Ge1−ySny alloys on Si are extended to Sn concentrations in the 1019−1020 cm−3 range. These concentrations are shown to be sufficient to engineer large increases in the responsivity of detectors operating at 1550 nm. The dopant levels of Sn are incorporated at temperatures in the 370–390 °C range, yielding atomically smooth layers devoid of threading defects at high growth rates of 15–30 nm/min. These conditions are far more compatible with complementary metal-oxide semiconductor processing than the high growth and processing temperatures required to achieve the same …

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Oxygen Vacancies Adjacent To Cu(2+) Ions In Tio(2) (Rutile) Crystals, A. T. Brant, Shan Yang (杨山), Nancy C. Giles, Zafar Iqbal, A. Manivannan, Larry E. Halliburton Apr 2011

Oxygen Vacancies Adjacent To Cu(2+) Ions In Tio(2) (Rutile) Crystals, A. T. Brant, Shan Yang (杨山), Nancy C. Giles, Zafar Iqbal, A. Manivannan, Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to characterize Cu2+ ions substituting for Ti4+ ions in nominally undoped TiO2 crystals having the rutile structure. Illumination at 25 K with 442 nm laser light reduces the concentration of Cu2+ ions by more than a factor of 2. The laser light also reduces the EPR signals from Fe3+ and Cr3+ ions and introduces signals from Ti3+ ions. Warming in the dark to room temperature restores the crystal to its preilluminated state. Monitoring the recovery of the photoinduced changes in the Cu …

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