PHASE II: Develop both analytical, first-principle theories, and random walk models of the radiative and conductive properties of optimized insulator media. Establish model extrapolation strategies for the best available model that minimizes the adverse effect of length scale changes. Optimize scattering, absorption, and morphological stability of heterogeneous porous media for temperatures exceeding 1650K. Transition technology to the industrial constructs.
PHASE III DUAL USE APPLICATIONS: Potential transition partners include the Air Force, DARPA, NASA and the U.S. industrial sector for hypersonic application. Alternative aeronautics markets may also be possible for air-breathing applications, industrial applications such as plasma processing and micro-fabrication techniques.
1. Lee, S. C., White, S., and Cunnington, G. R., 1994, “Effective Radiative Properties of Fibrous Composites Containing Spherical Particles,” J. Thermophysics and Heat Transfer, 8 (3), pp. 400-405.
2. Tetsuo Noguchi and Takeshi Kozuka, Principles of Radiant Heat Transfer. John Wiley & Sons, Inc., New York, 1960.
3. Cunnington, G. R., Lee, S. C., and White, S. M., 1998, “Radiative Properties of Fiber-Reinforced Aerogel: Theory vs Experiment,” J. Thermophysics and Heat Transfer, 12 (1), pp. 17-22. (Also, IV-10)
TITLE: Neutral Particle Dynamics in Transient Plasma to Determine Ground Test Chamber Interactions
TECHNOLOGY AREA(S): Space Platforms
OBJECTIVE: Develop measurement capability to determine neutral particle flow dynamics in plasma far from equilibrium.
DESCRIPTION: The impact of plasma source technology is expanding, ranging from innovative terrestrial applications such as water decontamination and purification, plasma processing, and plasma micro/nano-fabrication techniques to highly efficiency electric propulsion for satellites maneuvering[1,2]. Although the methods of plasma generation and operational environments are diverse, the ability to characterize neutral particle dynamics provides critical information on ionization processes, energy conversion, and interactions with surrounding materials. For plasma far from equilibrium and in extreme environments, the spatial and temporal variation of neutral particle properties drives plasma behavior and instabilities. However the dynamic variation in neutral distribution is extremely difficult to quantify. In many cases the direction of technology advances further exacerbates these challenges, such as the increased power and xenon gas propellant throughput of electric propulsion systems that are pushing the limits of ground test chamber pumping capability. Background pressures of world-class research, test and evaluation (T&E) vacuum chambers used for advanced electric propulsion are four or more orders of magnitude higher than the geostationary earth orbit (GEO) environment, and significant chamber upgrades are cost prohibitive. Historically, background pressures less than 3.0x10-5 torr were considered acceptable for flight qualification of electric propulsion systems. However in some cases, such as a Hall thruster, the elevated background neutral particles have impacted thruster instabilities, performance, lifetime, and exhaust ion plume. Thus, understanding the neutral particle dynamics is critical for T&E.
State-of-the-art neutral diagnostics for a partially ionized gas do not enable high-fidelity interrogation of both spatial and temporal features of the neutral dynamics at sufficient resolution needed to improve predictive plasma models, T&E capabilities, and develop next generation plasma source technologies. The objective is to measure neutral particle number density with measurement resolution of 1-10 microseconds and 1-5 mm in a partially ionized xenon gas. To this end, an innovative neutral particle diagnostic capability may be developed for a Hall thruster plasma source with xenon propellant, where xenon plasma number density is approximately 0.1-5.0x1018 /m3 and electron temperature ranges from 1eV to 40eV . Non-intrusive measurements that do not perturb the plasma, a portable diagnostic configuration, and cost-effective approaches are preferred.
Upon successful technology development, the measurement capability would be demonstrated and transitioned to Air Force research and/or test facilities.
PHASE I: Perform proof-of-concept analysis and experiments that demonstrate the feasibility of the neutral diagnostic measurement technique in partially ionized xenon gas. Identify key requirements for validating the technology, potential challenges, accuracy, limitations, and approach for Phase II demonstration.
PHASE II: Develop a fully functional neutral number density measurement capability with resolution of 1-10 microseconds and 1-5 mm in a partially ionized xenon gas. Demonstrate technology objectives with xenon propellant in a Hall thruster discharge at Air Force facility. Deliverables include diagnostic hardware, measurement uncertainty analysis, calibration technique, documentation, and data.
PHASE III DUAL USE APPLICATIONS: Potential transition partners include the Air Force, NASA and the U.S. industrial sector for commercial satellites. Alternative terrestrial markets may also be possible, industrial applications such as plasma processing and micro-fabrication techniques.
1. Malik, M. A., “Water Purification by Plasmas: Which Reactors are Most Energy Efficiency,” Plasma Chemistry and Plasma Processing, February 2010, Vol. 30, Issue 1, pp 21-31.
2. Perez-Martinez, C., Guilet, S., Gogneau, N., Gegou, P., Gierak, J., and Lozano, P.C., “Development of ion sources from ionic liquids for microfabrication,” Journal of Vacuum Science and Technology B 28, L25 (2010).
3. Randolph, T., Kim, K., Kaufman, H., Kozubsky, K., Day, M., “Facility Effects on Stationary Plasma Thruster Testing," Proceedings of the 23rd International Electric Propulsion Conference, Seattle, WA (Electric Rocket Propulsion Society, Fairview Park, OH, 1993), IEPC Paper No. 93-093.
4. Brown, D. L., Larson, C. W., Nakles, M. R., Gallimore, A. D., "Investigation of Low Discharge Voltage Hall Thruster Operating Modes and Ionization Processes,” 31st International Electric Propulsion Conference, IEPC-2009-074, Ann Arbor, MI, September 20-24, 2009.
5. Reid, B. M., and Gallimore, A. D., "Langmuir Probe Measurements in the Discharge Channel of a 6-kW Hall Thruster," 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, AIAA-2008-4920, Hartford, CT, Jul. 20-23, 2008.
KEYWORDS: neutral diagnostic, plasma, partially-ionized, Hall thruster
TITLE: Validation of Low Hydrogen Embrittlement (LHE) Alkaline Zinc Nickel Electroplating for Steel and Aluminum Electrical Connectors, Back-Shells and Components
TECHNOLOGY AREA(S): Materials/Processes
OBJECTIVE: Demonstrate environmentally friendly, low-hydrogen embrittlement (LHE) alkaline zinc nickel plating for replacing cadmium plating on steel and aluminum electrical connectors, back-shells and components for aircraft system components.
DESCRIPTION: Many of the electrical connectors currently used by DoD contain cadmium (Cd). Additional components on some DoD weapons systems require a ground path for static discharge (i.e., C-5 fuel tank vent caps). These components also require Cd plating due to highly corrosive environments. Cadmium is a known carcinogen. Furthermore, the cadmium is typically coated conversion coated with a hex-chromate which is also hazardous. Both the cadmium plating process and its subsequent conversion coating have been proven to be toxic (unlike other processes such as chromium plating, where a hazardous process yields a non-hazardous coating).
In January 2007, the U.S. President signed Executive Order (EO) 13423, Strengthening Federal Environmental, Energy, and Transportation Management, requiring government agencies to reduce the quantity of toxic and hazardous chemicals and materials that are acquired, used, or disposed. Cadmium is among the chemicals to be reduced by the DoD. Additionally, wastewater discharge from cadmium electroplating baths must meet effluent limitations dictated by regulations under the Clean Water Act, and any sludge from wastewater treatment must be managed as hazardous waste under the Resource Conservation and Recovery Act (RCRA). As a result of these regulations, the use of cadmium significantly raises the maintenance costs throughout the life of the plated parts. A cost-benefit analysis was conducted to analyze the cost impact of using an alternative coating in place of cadmium electroplating versus the costs of implementing a full medical surveillance program. Based on data from NADEP Cherry Point, elimination of cadmium electroplating would save the facility more than $20,000 per employee per year. The costs-per-square-inch for plating varies from facility to facility, but similar cost savings is anticipated at other DoD depots.
Due to these increasing costs, regulatory pressure, and risk to personnel performing these processes, the sustainability of the DoD’s surface treatment capability is somewhat threatened. Therefore, this effort seeks to gain approval for the use of Low Hydrogen Embrittlement (LHE) Alkaline Zn-Ni on aluminum and steel electrical connectors and other components with electrical/ground path critical applications. It is anticipated that the successful implementation of this alternative coating will not only comply with the requirements of EO 13423, but will also reduce total life-cycle costs of the weapon system.
PHASE I: Demonstrate plating technique to apply LHE alkaline Zn-Ni plating on aluminum and demonstrate the feasibility of replacing cadmium plating with a LHE alkaline zinc nickel plating on steel and aluminum electrical connectors, back-shells and components on aircraft and propeller system components.
PHASE II: Further develop, optimize and implement the approach from Phase I and demonstrate the process improvements with LHE alkaline zinc nickel electrical application development and test articles designed in Phase I. Mechanical and environmental properties, as well as process techniques, will be optimized and validated. Component alloy qualification testing and actual part service evaluation testing will be conducted.
PHASE III DUAL USE APPLICATIONS: The elimination of cadmium is beneficial for both military and commercial aircraft applications. Any aircraft currently utilizing cadmium plating on electrical connectors, back-shells and components for aircraft system components will have applications for this approach.
1. MIL-STD-870 Cadmium Plating, Type II, Class 2.
2. MIL-STD-1500 Cadmium Plating, Type II, Class 1.
3. AMS-QQ-P-416 Cadmium Plating, Type II, Class 2.
OBJECTIVE: The objective of this topic is to increase the depot energy efficiency by utilizing electrical energy produced by testing generators.
DESCRIPTION: The Air Force tests and repairs both airborne and ground power generators. The generators are mainly AC with one 277V DC generator. Several generators are run, sometimes for several hours at a time, to perform test and repair functions. There is an opportunity here to capture the power being created by the test generators. The Air Force desires to capture the test energy to enhance facilities energy efficiency and have a positive environmental impact.
The generator tests must conform to and meet technical order (TO) requirements. Essentially the generators are run/tested at 0-, 25-, 50- and 100-percent loads for a certain amount of time. The critical requirement is to be able to accurately apply the load while the test stand monitors the generator. There are both resistive and reactive elements to the loads that must be applied.
The AC generators produce either 120V or 208V output at either 60Hz or 400Hz. The size of the generators range form 10kW up to 900kW. The facility has both 120V and 208V electrical power.
PHASE I: Develop a solution that meets above requirements and conduct preliminary business case analysis (BCA) to determine implementation costs, including a return-on-investment (ROI) calculation that compares anticipated savings to expected costs. Proof-of-concept prototype(s) shall be developed to demonstrate conformance to the requirements. Investigate/prepare paper work for required certifications.
PHASE II: Proof-of-concept prototype(s) shall be refined to a flight-ready article and shall undergo testing to validate all requirements. This process may require multiple iterations before a final design is selected. Refine BCA/ROI based on the final design. Obtain certifications/authorization to put energy into the building / power grid.
PHASE III DUAL USE APPLICATIONS: If cost effective, implement developed technology.
1. DoD Directive 4140.25, DoD Management Policy for Energy Commodities and Related Services,
April 12, 2004.
2. DoD Directive 5126.46, Defense Energy Information System, December 2, 1987.
3. DoD Directive 5134.15, Assistant Secretary of Defense for Operational Energy Plans and Programs, May 17, 2011.
4. DoD Instruction 4170.10, Energy Management Policy, August 8, 1991.
5. Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance, October 5, 2009.
6. Energy Policy Act of 2005 (EPAct 2005), Public Law 109-58, August 8, 2005.
7. Energy Independence and Security Act (EISA) of 2007, Public Law 110-140, December 19, 2007.
8. U.S. Air Force Energy STRATEGIC PLAN, March 2013.
9. Energy Reduction at U.S. Air Force Facilities Using Industrial Processes, Copyright 2013.
OBJECTIVE: Find an automated method of identifying alloys (in a production environment) prior to processing in a chemical cleaning/stripping solution.
DESCRIPTION: The current process for identifying alloy groups is time consuming and prone to human error. It requires the technician to examine the part, identify a part number, and then compare that part number to a list of part numbers to determine the alloy(s) present in the part. Misidentification of the part happens far too often, resulting in the parts being placed in the wrong chemical solution, resulting in damage to the part. Every part that is placed in the wrong solution must be evaluated by an engineer, and can result in the part being condemned for further use. The parts needing to be cleaned usually contain dirt on them or have various coatings on them that hinder the ability to identify the alloy(s). Titanium, aluminum, and magnesium are the alloys that cause concern, because the various chemical solutions used can damage these alloys.
Evaluate methods available for detecting the following alloys (at a minimum): titanium, aluminum, and magnesium in aircraft and aircraft engine parts in a production (not laboratory) environment. Successful methods should correctly identify the alloy(s) in a matter of seconds, not minutes, with a very high probability of detection. Parts to be tested should have various coatings and them and can possibly be dirty. The coatings and dirt would be such that you would find on a typical aircraft part or typical aircraft engine after it has been in use for hundreds or even thousands of hours.
PHASE I: Research and develop concept demonstration that shows technology proposed addresses the above requirements
PHASE II: Prototype the detection method first in a laboratory and then in a production environment at Tinker AFB, Oklahoma. Conduct multiple trials and refine the method by testing it against various aircraft and aircraft engine parts (of all sizes and types) to ensure that it works regardless of part being tested.
PHASE III DUAL USE APPLICATIONS: Transition the method to AFMC for use in its facilities at Tinker AFB, Oklahoma; Hill AFB, Utah; and Warner-Robins AFB, Georgia, as well as any other Air Force or DoD facilities that could benefit from it.
1. Process Order 86-005.
2. Technical Order 2-1-1-11.
KEYWORDS: material sensor technology, chemical cleaning, chemical stripping, alloys, titanium, magnesium, aluminum, coatings
TITLE: Additive Manufacturing Technique for Replacement of Complex Castings
TECHNOLOGY AREA(S): Materials/Processes
OBJECTIVE: Research and develop agile/additive manufacturing technologies for Air Force to replace traditionally complex cast tooling or the current cast parts with high precision tolerances and intricate internal features that cannot be machined.
DESCRIPTION: Many aerospace systems require intricate castings of aluminum or steel parts with multiple internal surfaces that are very difficult to make resulting in a very high first article failure rate. In addition, many are needed in low volume making production runs extremely costly and time consuming to manufacture. A technology is being sought that has the ability to employ additive manufacturing techniques to resolve the manufacturing complexity, cost and time issues created through the traditional casting approach. This technique must produce parts accurate to 0.0005 inches with an objective of 0.001-inch threshold for the entire part. The technology must be capable of placing material with properties meeting or exceeding the material properties currently used in each application. These materials include, but are not limited to A356-T6 Al, 7075-T651 AL, CRE Steel (15-5PH and 17-4PH), 4140 and 4340 Steel. Secondary manufacturing procedures, such as heat treatment or protective finishing, are allowed to achieve final properties. The bounding box for most parts is 18 in x 18 in x18 in or less though some parts would require a larger capacity of approximately 24 in x 24 in x 36 in. The final operation should be as automated as possible and require very little user training. The technology must leverage information from a fully annotated solid model to define its finished shape.
Limitations of current casting techniques drive high cost and schedule requirements for many aerospace system components especially when purchased at low volume. Additive manufacturing has demonstrated strong potential for being utilized as a replacement but has not yet been demonstrated for the size, strength and volume of these applications. This project will most likely require new innovative equipment and processes to be developed to demonstrate the ability of the technology to meet the requirements of each phase.
To support this effort an Agile/Additive Manufacturing government team will be identified and assigned from across the Air Force Sustainment Center, Air Force Life Cycle Management Center, and Air Force Research Laboratory to assist in the Phase I effort. The team will assist in part selection and in providing any supportive part technical information that is available. In many cases it may be necessary to reverse engineer the part and create the data needed.
PHASE I: Research and develop a scoped effort to explain how agile/additive manufacturing can replace current casting tooling and selected casted parts without the need for cast tooling in a concept demonstration. The final report can detail requirements for any proposed Phase II continued development to meet tolerance objects shown above.
PHASE II: Based on the Phase I concept, continue the research/development for prototype demonstration on selected cast tooling and cast parts jointly agreed on by proposer and the government support team. Final report will document results, benefits, any airworthiness test requirements and transition plan required to complete transition into production capability.
PHASE III DUAL USE APPLICATIONS: The technology developed during Phase II will allow enhancements to expand to more complex cast tooling or parts with tighter tolerances.
1. Y. Liu, D. W. Lipke, Y. Zhang, K. H. Sandhage, “The Kinetics of Incongruent Reduction of Tungsten Carbide (WC) via Reaction with a Hafnium-Copper (Hf-Cu) Melt,” Acta Mater., 57, 3924-3931 (2009).
TITLE: Acoustic Emission of Frangible, Composite, Concrete and Metallic Radar Towers
TECHNOLOGY AREA(S): Materials/Processes
OBJECTIVE: Research and develop the acoustic emission (AE) technology into a non-destructive inspection (NDI) sustainment/inspection tool. This technology will be applied to towers (composite and metallic), as well as the composite concrete foundations.
DESCRIPTION: Advanced radar notification is a critical item for warfighter capabilities. The ongoing sustainment and inspections of these facilities is critical to the warfighter capabilities. Many of the radar sites throughout the world are over 50 years old and have had very little NDI inspections. For five years the NDI Program Office (NDIPO) at Hill AFB, Utah, has been involved in a sustainment/inspection program. In the past five years of inspections, there have been very little inspection breakthroughs. Due to lack of access to welds and the difficult location of many parts of the towers, no standard methods have been developed. Visual inspection of welds using a bore scope and pulse echo ultrasonic on assembly bolts have been the extent of inspection capability. An NDI inspection method that is more sensitive than visual inspection will be a vast improvement for the reliability of the NDI inspections.
The AE technology will allow the placement of sensors at selected locations on the towers. The natural stress of the radar rotation will provide a mechanism to cause an acoustic emission. The acoustic emission instrumentation shall capture and provide data for permanent record and analysis. This same NDI method has an application on fiberglass reinforced plastic (FRP) towers that are being installed present day. There is also some potential that the method may offer some data on the composite concrete foundations for many of these towers.