Localization of Virtual Auditory Cues in a High +Gz Environment

: This report describes all SBIR Phase 2 effort to validate a mathematical model mid conduct a design study of the Air Force Dynamic Environment The Dynamic Environment Simulator, or DES, is a three degree-of-freedom centrifuge operated by Armstrong Laboratories at Wright-Patterson AFB. The effort was conducted under Contract F41624-96-C-6027 through the Armstrong Laboratory and was entitled Model Validation and Design Study of the Dynamic Environment Simulator. This Phase 2 project had four primary objectives, which were to: (1) Validate the Phase 1 software model of the DES; (2) Conduct a design study of DES improvements; (3) Perform a cost/benefit analysis of the possible DES improvements; and (4) Demonstrate the commercial potential of the model and the DES.

This paper examines the problem of simulating angular velocity fields that may for example, be experienced by a pilot during a supermaneuverable flight trajectory. The ability to simulate angular velocity fields has important applications in the study of certain physiological effects encountered by pilots during these unusual flight scenarios. The simulations are to be performed using a centrifuge simulator called the Dynamic Environment Simulator (DES) located in the Armstrong Laboratory of Wright-Patterson Air Force Base. Some of the kinematic issues relating to the motion control of the DES are examined in the paper. >

The Air Force Research Laboratory (AFRL) Scholars Program offers stipend-paid summer internship opportunities to undergraduate- and graduate-level university students as well as upper-level high school students who are pursuing or plan to pursue degrees in science, technology, engineering, and mathematics (STEM). Internships through the AFRL Scholars Program are currently offered through the Directed Energy, Space Vehicles, and Munitions Directorates of AFRL with locations at Kirtland Air Force Base, New Mexico, Eglin Air Force Base, Florida, and Maui, Hawaii. Throughout their internships, AFRL Scholars gain valuable hands-on experience working with full-time AFRL scientists and engineers on cutting-edge research and technology. Overall, the selected interns are able to contribute to unique, research-based projects which often contain a strong emphasis in optics and photonics. This paper celebrates the continued success of the AFRL Scholars Program and shares a statistical overview of its growth over the past few years. In particular, the analysis focuses on how these STEM-related internships will hopefully meet the needs of an aging AFRL workforce in the years to come. This paper also provides an overview of two optics and photonics related internships at the undergraduate and graduate levels, respectively. Both interns received the Outstanding AFRL Scholar Award in their respective categories and are currently pursuing careers in optics and photonics based on their experiences as AFRL Scholars.

Differentiating responses of weather files and local climate change to explain variations in building thermal-energy performance simulations

The Air Force Research Laboratory (AFRL) developed an initial plug-and-play capability for spacecraft to better define interfaces, similar to USB on personal computers, in order to simplify spacecraft development and reduce cost and schedule. Much of this improved definition involves standardizing software interfaces between spacecraft components and a spacecraft network. The Spacecraft Avionics Experiment (SAE) was developed and flown as a secondary experiment on the AFRL TacSat-3 spacecraft as the first on-orbit demonstration of the Space Plug-and-Play Architecture (SPA) capability. On numerous occasions during SAE development and test, the modular, reconfigurable SPA interface provided significant cost and schedule savings. SAE consisted of a SPA-USB (SPA-U) network with multiple plug-and-play components with the objective of demonstrating as much core avionics and spacecraft operation as possible in a small secondary payload package. To this end, most elements of a Guidance, Navigation, and Control (GN&C) system were incorporated, to include a sun sensor, rate sensor, temperature sensors, and an AC coupled interconnect experiment. SAE also provided operational backups for TacSat-3 to include a Surrey SGR-05 GPS receiver and a backup high speed SPA-SpaceWire (SPA-S) link between the hyperspectral image processor and the C&DH for payload data transfer. Active GN&C control elements were not included so as not to risk spacecraft stability and control. SAE used built-in self test functions to verify on-orbit performance autonomously. The primary mission of TacSat-3 was to provide hyperspectral imaging data and to receive tasking, collect the data, and downlink to the tactical warfighter in a single flight over theater. TacSat-3 launched on 19 May 2009 and transitioned to the operational user on 12 June 2010. During TacSat-3 on-orbit experimental operations between these dates, SAE performed numerous experiment data collects. Both the SPA-U and SPA-S interfaces operated as designed. One of the SPA-U experiments had a SEU detector on board and no SEUs were observed during experiment operations. SPA-S demonstrated data transfers at 75 Mbps rate with no bit errors observed on orbit. SAE was developed for AFRL by the Space Systems Group at Sierra Nevada Corporation.

Thin-film solar cells offer great promise for increasing the capability of future spacecraft. While their efficiencies are low compared to state of the art crystalline solar cells, they have unique attributes that make them very attractive for space use. These attributes include flexibility, low mass, and low cost production. The attractive attributes of thin-film solar cells will go untapped until space environmental effects on them are well understood. Therefore, on-orbit testing of thin-film solar cells, coupled with ground testing, is needed to provide the data to determine space environmental effects. In response to the need to perform on-orbit testing of thin-film solar cells, the Space Vehicles Directorate of the Air Force Research Laboratory (AFRL) is preparing two flight experiments. The first will be on the AFRL Roadrunner Mission (Experimental Solar Array) and the second will be on the AFRL Deployable Structures Experiment (Thin-Film Photovoltaics Experiment).

: Females are now flying combat aircraft in the Air Force. Questions Of gender differences regarding adaptation and performance)in the high environment (9G) must be studied Scientifically. The Dynamic Environment Simulator, a three- axis centrifuge with closed-loop flight simulation, provides the laboratory to investigate the issues. Results. The eight women in this high-G performance study did not show cardiovascular adaptation to high whereas the eight men did. Both genders showed increased leg calf compliance indicating possible chronic vascular effects. No echocardiographic graphic evidence of heart damage was found The women demonstrated half the strength of the men, but displayed similar G tolerance and endurance. The women showed less oxygen desaturation of brain tissue than the men during high exposure. The women did not perform the simulated air-to-air combat sortie quite as well as the men, though there was no effect of menstrual cycle on their ability to complete the mission There was no effect of high exposure on the length Or the female monthly cycle, regardless of oral contraceptive use. Conclusion. Women demonstrated acceptable tolerance to and performance during simulated high aerial combat, without menstrual effect, even in light of their reduced muscular strength and cardiovascular adaptation as compared to men.

A colored traveling salesman problem (CTSP) is a path optimization problem in which colors are used to characterize diverse matching relationship between cities and salesmen. Namely, each salesman has a single color while every city has one to multiple salesmen’s colors, thus allowing salesmen to visit exactly once the cities of their colors. It is noteworthy that cities’ accessibilities to salesmen may change over time, which usually takes place in the multiwarehouse distribution of online retailers. This work presents a new CTSP with dynamically varying city colors for describing and modeling some scheduling problems with variable city accessibilities. The problem is more complicated than the previously proposed CTSP with varying edge weights. In particular, the solution feasibility changes as the cities change their colors, that is, a feasible original solution path may become no longer feasible after city colors change. A variable neighborhood search (VNS) algorithm is presented to solve the new problem. Specifically, a dynamic environment simulator with an adjustable frequency and amplitude is designed to mimic such color changes. Then, direct-route encoding, greedy initialization, and appropriate population immigrant are proposed to form an enhanced VNS, and then its performance is evaluated. The results of extensive experiments show that the proposed VNS can quickly track the environmental changes and effectively resolve the problem.

: Twenty-two student test pilots have participated in closed-loop tracking indoctrination runs on the Dynamic Environment Simulator. Each pilot flew through a series of profiles up to 6 G in both the conventional upright seat position and a 55 degrees tilt back seat position. The subjective responses and pilot questionnaires are presented.

This project is part of a research effort to design a hydrogen plant and its interface with a nuclear reactor. This project developed a dynamic modeling, simulation and optimization environment for nuclear hydrogen production systems. A hybrid discrete/continuous model captures both the continuous dynamics of the nuclear plant, the hydrogen plant, and their interface, along with discrete events such as major upsets. This hybrid model makes us of accurate thermodynamic sub-models for the description of phase and reaction equilibria in the thermochemical reactor. Use of the detailed thermodynamic models will allow researchers to examine the process in detail and have confidence in the accurary of the property package they use.

: In the past, laboratory simulators have, because of technical limitations, usually been restricted to reproduce isolated segments of the operational environment. The next generation of simulators will provide the ability to create the high-magnitude, complex accelerations of operational environments for exploration of the biomechanics, physiologic, and performance changes resulting from exposure of humans and animals to those environments. A six-degree-of-freedom motion device, operating in the 0-30 cps range to produce complex vibrations with peak loads up to plus or minus 15 g, a dynamic pressure chamber (that will create sound pressure fluctuations of up to 172 db in the 0- 100 cps frequency range), and a dynamic escape simulator (a sophisticated centrifuge) that will permit suprapositioning of sustained acceleration of up to 20 g's with high-magnitude, complex, angular and linear motion and a wide range of atmospheric pressures and temperatures are now under construction. A design study on a horizontal impact research device has been completed. The specific design characteristics and performance range of these devices are compared to the environments produced by operational conditions and to existing laboratory simulation facilities.

I. Introduction Recent results of high acceleration experiments at the University of Washington ram accelerator are presented. Ram accelerators can currently accelerate projectiles up to a velocity of ~ 2.7 km/s, however, many of the potential applications for ram accelerators are dependent on achieving even higher velocities. A research effort is currently underway to maximize the velocity capability of the University of Washington ram accelerator by increasing the sustained acceleration in each stage. For thermally choked operation, thrust will be higher at lower Mach numbers and with propellants having higher levels of chemical energy release. Acceleration at a given thrust can be increased by decreasing the mass of the projectile itself. These characteristics of ram accelerator operation are exploited to demonstrate high velocity capabilities. Previous research into geometry effects identified a low mass projectile configuration which can be accelerated via the thermally choked operating mode to the Chapman-Jouguet detonation velocity. A technique was developed which identifies high acceleration mixtures in relatively few experiments, by comparing the Mach number, chemical heat release, and theoretical acceleration level over a stage of a given length. This technique is utilized to achieve record levels of sustained acceleration. Experiments were performed with the reduced-mass projectile in propellant mixtures of methane, oxygen and helium, staged to minimize the Mach number as the projectile travels down the tube. Average accelerations of 38,000 g over a single 2-m stage and 34,000 g over three 2-m stages have been observed, yielding velocities of 2400 m/s after 6m. These experiments demonstrate a significant improvement in sustained acceleration performance. The ram accelerator is a chemical hypervelocity launcher used to accelerate projectiles to velocities on the order of several kilometers per second.1 It operates on the same operating principles as a conventional supersonic ramjet: a system of shock waves attached to a diffuser compress a fluid to which heat is added via combustion, producing thrust. In a ramjet fuel is added after the air has been decelerated to subsonic speeds. The fuel-air mixture is burned and accelerated to supersonic conditions via a constricting nozzle throat, exhausting out the rear of the engine. In a ram accelerator (Fig. 1), a projectile with a conical nose and tapering rear section is injected into a tube filled with premixed gaseous fuel and oxidizer. The shock waves attached to the projectile compress the propellant mixture, which is then burned. The resulting pressure increase accelerates the projectile down the tube. The combustion stays with the projectile, allowing very high velocities to be attained.

The US Air Force Research Laboratory has actively pursued the development of the Chemical Oxygen-Iodine Laser (COIL) since its invention in 19771. The power scaling potential of the COIL was verified in the late 1980's on the RotoCOlL device, which was later decommissioned. A smaller COIL teststand (ReCOIL) was then upgraded with a rotating-disk oxygen generator and a variable-height slit nozzle to become the principal testbed for continued COIL development. The modified device was named the Research assessment evice Iodine chemical Laser (RADICL). RADICL has supported several major test campaigns during the past 9 years, many of which have been published. These include 2-D gain maps2, iodine dissociation studies3, magnetic gainswitching demonstrations4, mode-locking5, metal cutting/fiber delivery demonstrations, and more recently measurements of water concentration and oxygen yield . Areview of the major results of these test programs and previously unpublished data are presented.

Mass spectrometry is a versatile research tool that has proved to be extremely useful for exploring the fundamental nature of the earth's atmosphere and ionosphere and in helping to solve operational problems facing the Air Force and the Department of Defense. In the past 40 years, our research group at the Air Force Research Laboratory has flown quadrupole mass spectrometers of many designs on nearly 100 sounding rockets, nine satellites, three Space Shuttles and many missions of high-altitude research aircraft and balloons. We have also used our instruments in ground-based investigations of rocket and jet engine exhaust, combustion chemistry and microwave breakdown chemistry. This paper is a review of the instrumentation and techniques needed for space research, a summary of the results from many of the experiments, and an introduction to the broad field of atmospheric and space mass spectrometry in general.

This paper presents the status and results from an ongoing development and flight test program that is investigating both reusable nanosat launch vehicles (RNLV), with an emphasis on fast turn-around operations, and early pathfinding for operationally responsive space. A related objective is enhancing the Technology Readiness Level of candidate launch vehicle technologies whenever they can be accommodated as complementary research experiments. The present program builds upon previous work that featured four flight tests (two conducted in a single day within 3.5 hours) with an earlier prototype RNLV first stage (the Prospector 7) that was developed under a Phase I SBIR sponsored by the Air Force Research Laboratory - Propulsion Directorate with support from the Air Force Space & Missile Systems Center. Recent work that falls under the scope of a follow-on Phase II SBIR contract has focused on developing a next-generation prototype RNLV first stage. The Phase II objective is to improve both the performance environment and operational fidelity of these flight tests, thereby bringing them closer to those anticipated for orbital missions. Milestones during the past two years have included horizontal static fire testing of a new 4.5 klbf-thrust LOX/ethanol first stage engine, vertical static fire testing of this engine with an interim test vehicle (the Prospector 8) and its initial flight demonstration, and integration and an initial static fire test attempt with the next prototype vehicle (the Prospector 9). Among the latter’s most notable design features are two full-scale composite cryogenic propellant tanks. Final integration and operational preparations are gearing up to initiate low-altitude flight testing later this summer.