Warner J.J.,Hill Air force Base |
Clark P.N.,Southwest Research Institute |
Hoeppner D.W.,University of Utah
International Journal of Fatigue | Year: 2014
The increased number of aging aircraft in operation today requires a deeper understanding of fatigue life improvement methods. This research focused on the fatigue life benefit from cold expanded holes with preexisting cracks approximately 1.270 mm (0.050 in.) long under constant amplitude and wing spectrum loading. Holes with preexisting cracks were tested to simulate the worst case scenario of a hole with a crack the size of the detection threshold, 1.270 mm (0.050 in.), present before cold expansion that was not found by Non Destructive Inspection. Test results were compared to crack growth models generated in AFGROW. At high stress levels the AFGROW models yielded non conservative results greater than 150% of the test demonstrated fatigue life.
Kelly P.B.,Hill Air force Base
AUTOTESTCON (Proceedings) | Year: 2012
Testing involves applying stimulus to a device, called the Unit Under Test (UUT), and evaluating the measured response against the expected values. Traditional systems use discrete instruments to supply the stimulus and measure the response, but most devices are part of a larger system and may be a component of a closed control loop. Many devices are designed to respond to the inputs by generating outputs that are dependent on some part of the output being fed back to the inputs through the rest of the system. To be comprehensive, a test of such a device must include stimulus and response that matches, as closely as possible, the way the device is used in the full system. This requires test equipment that can alter the stimulus in response to the UUT's outputs. For low speed systems, software can often accomplish this, which is the traditional approach, but systems that require much faster response than practically accomplished in software are simply not tested in this fashion unless custom test hardware is designed to do it. This drives up the cost of test station and test program design, development, and maintenance, making it prohibitive except where crucial. © 2012 IEEE.
Chase B.,Hill Air force Base
AUTOTESTCON (Proceedings) | Year: 2014
The Air Force A-10C attack aircraft is currently experiencing obsolescence issues with its legacy support equipment. The Portable Automated Test Station Model 70 (PATS-70) replaces over a dozen pieces of obsolete and irreparable flightline support equipment. The PATS-70 is a robust, flightline qualified test set that has gone through rigorous MIL-STD-810G, and MIL-STD-416F environmental testing. While it was developed to function as maintenance support equipment for the A-10C aircraft, it has no A-10 specific components so it can be adapted for maintenance on other aircraft, platforms, or systems. This paper describes the history of the PATS-70 and discusses the advantages to using it to maintain systems throughout the Department of Defense. © 2014 IEEE.
Doucette W.J.,Utah State University |
Hall A.J.,Utah State University |
Gorder K.A.,Hill Air force Base
Ground Water Monitoring and Remediation | Year: 2010
Groundwater contamination associated with an industrial facility in Utah has led to concerns about potential vapor intrusion into residences outside the facility boundary. Trichloroethylene (TCE) is the main contaminant of concern with 1,2-dichloroethane (1,2-DCA) present in some areas. An air-monitoring program implemented to detect vapor intrusion of these compounds found 1,2-DCA in homes outside areas of groundwater contamination, suggesting indoor sources in these cases. Investigative indoor air and product sampling were conducted to isolate consumer products emitting 1,2-DCA and to quantify the emission rates of identified products. The combination of room-by-room air sampling and emission measurements was successfully used to identify molded plastic holiday ornaments, having measured emission rates as high as 0.3 μg 1,2-DCA/min. Subsequent testing of seven comparable retail items found similar 1,2-DCA emissions. Screening-level calculations show that the measured emission rates of 1,2-DCA from these items can lead to indoor concentrations high enough to be of regulatory concern (0.094 to 9.4 μg/m3 based on 10-6 to 10-4 cancer risk levels). © 2009 National Ground Water Association.
Ligrani P.,University of Oxford |
Ligrani P.,Hill Air force Base |
Goodro M.,University of Oxford |
Goodro M.,Saint Louis University |
And 2 more authors.
Journal of Heat Transfer | Year: 2013
Experimental results are presented for a full-coverage film cooling arrangement which simulates a portion of a gas turbine engine, with appropriate streamwise static pressure gradient. The test surface utilizes varying blowing ratio (BR) along the length of the contraction passage which contains the cooling hole arrangement. For the different experimental conditions examined, film cooling holes are sharp-edged and streamwise inclined either at 20 deg or 30 deg with respect to the liner surface. The film cooling holes in adjacent streamwise rows are staggered with respect to each other. Data are provided for turbulent film cooling, contraction ratios of 1, 3, 4, and 5, blowing ratios (at the test section entrance) of 2.0, 5.0, and 10.0, coolant Reynolds numbers Refc of 10,000-12,000, freestream temperatures from 75 °C to 115 °C, a film hole diameter of 7 mm, and density ratios from 1.15 to 1.25. Nondimensional streamwise and spanwise film cooling hole spacings, X/D and Y/D, are 6, and 5, respectively. When the streamwise hole inclination angle is 20 ° spatially averaged and line-averaged adiabatic effectiveness values at each x/D location are about the same as the contraction ratio varies between 1, 3, and 4, with slightly higher values at each x/D location when the contraction ratio Cr is 5. For each contraction ratio, there is a slight increase in effectiveness when the blowing ratio is increased from 2.0 to 5.0 but there is no further substantial improvement when the blowing ratio is increased to 10.0. Overall, line-averaged and spatially averaged-adiabatic film effectiveness data, and spatially averaged heat transfer coefficient data are described as they are affected by contraction ratio, blowing ratio, hole angle , and streamwise location x/D. For example, when = 20 deg, the detrimental effects of mainstream acceleration are apparent since heat transfer coefficients for contraction ratios Cr of 3 and 5 are often higher than values for Cr = 1, especially for x/D > 100. © 2013 by ASME.
Dennison J.R.,Utah State University |
Evans A.,Utah State University |
Fullmer D.,Utah State University |
Hodges J.L.,Hill Air force Base
IEEE Transactions on Plasma Science | Year: 2012
The effects of prolonged exposure to the low Earth orbit space environment and charge-enhanced contamination on optical, thermal, and electron emission and transport properties of common spacecraft materials have been investigated by comparing pre- and postflight characterization measurements. The State of Utah Space Environment and Contamination Study (SUSpECS), deployed in March 2008 on board the Materials International Space Station Experiment (MISSE-6) payload, was exposed for ∼18 months on the exterior of the International Space Station (ISS) and was retrieved in September 2009. A total of 165 samples was mounted on three separate SUSpECS panels on the ram and wake sides on the ISS. Some samples, particularly those exposed to atomic oxygen in the ram direction, showed pronounced effects due to exposure. Biased samples for the charge-enhanced contamination study showed subtle variations in visible and infrared reflectivity. © 2011 IEEE.
Wisnewski A.V.,Yale University |
Stowe M.H.,Yale University |
Nerlinger A.,Yale University |
Opare-Addo P.,Yale University |
And 3 more authors.
Annals of Occupational Hygiene | Year: 2012
Objectives:Isocyanate chemicals essential for polyurethane production are widely used industrially, and are increasingly found in consumer products. Asthma and other adverse health effects of isocyanates are well-documented and exposure surveillance is crucial to disease prevention. Hexamethylene diisocyanate (HDI)-specific serum immunoglobulin G (IgG) was evaluated as an exposure biomarker among workers at a US Air Force Air Logistics Center, which includes a large aircraft maintenance facility.Methods:HDI-specific IgG (HDI-IgG) titers in serum samples (n = 74) were measured using an enzyme-linked immunosorbent assay based upon the biuret form of HDI conjugated to human albumin. Information on personal protective equipment (PPE), work location/tasks, smoking, asthma history, basic demographics, and HDI skin exposure was obtained through questionnaire.Results:HDI-specific serum IgG levels were elevated in n = 17 (23%) of the workers studied. The prevalence and/or end-titer of the HDI-IgG was significantly (P < 0.05) associated with specific job titles, self-reported skin exposure, night-shift work, and respirator use, but not atopy, asthma, or other demographic information. The highest titers were localized to specific worksites (C-130 painting), while other worksites (generator painting) had no or few workers with detectable HDI-IgG.Conclusions:HDI-specific immune responses (IgG) provide a practical biomarker to aid in exposure surveillance and ongoing industrial hygiene efforts. The strategy may supplement current air sampling approaches, which do not assess exposures via skin, or variability in PPE use or effectiveness. The approach may also be applicable to evaluating isocyanate exposures in other settings, and may extend to other chemical allergens. © 2012 The Author 2012. Published by Oxford University Press on behalf of the British Occupational Hygiene Society .
Dunkley R.,Hill Air force Base
AUTOTESTCON (Proceedings) | Year: 2012
Supporting a variety of communication protocols for test support equipment has typically required extensive hardware and Input/Output (I/O) interfaces targeting each protocol specifically. Recent advanced designs in the past ten years have created more dynamic approaches by using Field Programmable Gate Arrays (FPGAs) and embedded hardware to implement or simulate previous hardware I/O designs. The dynamic possibilities of FPGAs have recently been expanded with the introduction of Dynamic Partial Reconfiguration (DPR), which allows part of the FPGA to be reconfigured while the rest of the logic remains static. This paper evaluates the advantages and disadvantages of using DPR to interface with various communication protocols in test equipment. © 2012 IEEE.
Gorder K.A.,Hill Air force Base |
Dettenmaier E.M.,Hill Air force Base
Ground Water Monitoring and Remediation | Year: 2011
A portable gas chromatograph-mass spectrometer (GC/MS) was used to investigate sources of chlorinated volatile organic compound (cVOC) contamination in indoor air at 46 residences around Hill AFB, Utah, that were potentially affected by vapor intrusion. Analytical methods were developed to allow sample turnaround times of less than 10 min and method detection limits (MDLs) generally less than 1 μg/m3 for a selected list of cVOCs. Area-by-area sampling was used to identify the likely vapor source locations. In many cases, individual container/enclosure sampling and subsequent field emission rate measurements from isolated consumer products were used to determine if identified products were likely to be the primary source of vapors in the residence. The portable GC/MS was also used to characterize vapor intrusion in two residences. In one of these two residences, building pressure control was used to enhance vapor entry in order to facilitate the investigation resulting in confirmation of vapor intrusion and identification of a primary route of vapor entry. cVOCs were identified in 42 of the 46 homes investigated, subsurface vapor intrusion was identified in two homes, and two homes had inconclusive results. © 2011, National Ground Water Association.
McHugh T.,Gsi Environmental |
Kuder T.,University of Oklahoma |
Fiorenza S.,British Petroleum |
Gorder K.,Hill Air force Base |
And 2 more authors.
Environmental Science and Technology | Year: 2011
At buildings with potential for vapor intrusion of volatile organic chemicals (VOCs) from the subsurface, the ability to accurately distinguish between vapor intrusion and indoor sources of VOCs is needed to support accurate and efficient vapor intrusion investigations. We have developed a method for application of compound-specific stable isotope analysis (CSIA) for this purpose that uses an adsorbent sampler to obtain sufficient sample mass from the air for analysis. Application of this method to five residences near Hill Air Force Base in Utah indicates that subsurface and indoor sources of tricholorethene and tetrachloroethene often exhibit distinct carbon and chlorine isotope ratios. The differences in isotope ratios between indoor and subsurface sources can be used to identify the source of these chemicals when they are present in indoor air. © 2011 American Chemical Society.