Digital Commons Network^™

Grating Lobe Reduction In Aperiodic Linear Arrays Of Physically Large Antennas, William C. Barott, Paul G. Steffes

Publications

We present performance bounds obtained from the optimization of the sidelobe levels of aperiodic linear arrays. The antennas comprising these arrays are large compared to the distance between neighboring antennas, a case not addressed in previously published work. This optimization is performed in pattern-space and is applicable over a wide range of scan angles. We show that grating lobes can be suppressed even when the elemental antennas are several wavelengths in size, provided that the ratio of the antenna size to the average spacing between the antenna center-points does not exceed 80%.

Airport Bird Hazard Management, Flavio A. C. Mendonca Ph.D.

Publications

Aircraft collisions with birds, also commonly referred to as bird strikes, annually cost the commercial aviation industry in Brazil at least $6 million in direct damage and associated costs and hundreds of hours of aircraft down time. Although the economic costs of wildlife strikes are extreme, the cost in human lives lost when aircraft accidents occur as a result of strikes best illustrates the need for management of the wildlife strike problem. Bird strikes have been an increasing problem for the aviation industry. Air travel has become widespread all over the world. The aircraft has played an important role not …

"Sie Kommen" (They're Coming), David Hamilton

ERAU Prescott Aviation History Program

The exciting story of the training, mission briefings and overall planning that lead to the success and failure of major troop carrier operations in World War II. Told by a C-47 pilot who flew ‘pathfinder’ missions on D-Day; supply missions for Bastogne; and for ‘Market Garden’, the invasion of Holland.

Heavy-Fueled Intermittent Ignition Engines: Technical Issues, Jeffrey Arthur Schneider, Timothy Wilson, Christopher Griffis, Peter Pierpont

Publications

This report contains an overview of the technology and engineering issues with nonturbine heavy-fueled engines for general aviation aircraft and Unmanned Aircraft Systems. In recent years, interest in these types of engines has grown, partly due to the cost, safety, and worldwide availability of gasoline fuels. Within 3 to 5 years, up to five engines will seek Federal Aviation Administration certification as heavy-fuel powerplants. Although there has been some progress, there is no universal standard for certification of these engines (under Title 14 Code of Federal Regulations (CFR) Part 33), or their installation into normal category fixed-wing aircraft or rotorcraft …

Unmanned Aircraft System Propulsion Systems Technology Survey, Christopher Griffis, Timothy Wilson, Jeffrey Schneider, Peter Pierpont

Publications

This technology survey is an investigation of various propulsion systems used in Unmanned Aircraft Systems (UAS). Discussed are existing and near-future propulsion mechanisms of UAS, such as reciprocating piston engines, Wankel rotary engines, gas turbine engines, rocket-powered systems, electric motors, and battery-based systems. Also discussed are systems that use proton exchange membrane fuel cells, photovoltaics, ultracapacitors, and propellers. Each system is described in reference to a larger conceptual framework, with instances and profiles of existing UAS employing the system being described. Advantages and disadvantages of each type of propulsion system are identified along with associated technical issues and their respective …

Waves In Inhomogeneous Solids, Arkadi Berezovski, Mihhail Berezovski, Juri Engelbrecht

Publications

The paper aims at presenting a numerical technique used in simulating the propagation of waves in inhomogeneous elastic solids. The basic governing equations are solved by means of a finite-volume scheme that is faithful, accurate, and conservative. Furthermore, this scheme is compatible with thermodynamics through the identification of the notions of numerical fluxes (a notion from numerics) and of excess quantities (a notion from irreversible thermodynamics). A selection of one-dimensional wave propagation problems is presented, the simulation of which exploits the designed numerical scheme. This selection of exemplary problems includes (i) waves in periodic media for weakly nonlinear waves with …

Aviation Safety Information Analysis And Sharing -- General Aviation (Asias -- Ga), Alan J. Stolzer

Publications

A presentation on the collaborative government and industry initiative on data sharing and analysis to proactively discover safety concerns before accidents or incidents occur, leading to timely mitigation and prevention.

Developing Abrasion Test Standards For Evaluating Lunar Construction Materials, Ryan L. Kobrick, David M. Klaus, Kenneth W. Street

Publications

Operational issues encountered by Apollo astronauts relating to lunar dust were catalogued, including material abrasion that resulted in scratches and wear on spacesuit components, ultimately impacting visibility, joint mobility and pressure retention. Standard methods are being developed to measure abrasive wear on candidate construction materials to be used for spacesuits, spacecraft, and robotics. Calibration tests were conducted using a standard diamond stylus scratch tip on the common spacecraft structure aluminum, Al 6061-T6. Custom tips were fabricated from terrestrial counterparts of lunar minerals for scratching Al 6061-T6 and comparing to standard diamond scratches. Considerations are offered for how to apply standards …

Access Mars: Assessing Cave Capabilities Establishing Specific Solutions: Final Report, Abdul Mohsen Al Husseini, Luis Alvarez Sanchez, Konstantinos Antonakopoulos, Jeffrey (Johannes) Apeldoorn, Kenneth Lowell Ashford Jr., Kutay Deniz Atabay, Sara Langston, Et Al.

Publications

The human race has evolved, grown and expanded through the exploration of Earth. After initial steps on the Moon, our next challenge is to explore the solar system. Mars shows potential for both scientific discovery and future human settlement, and so is a prime candidate for the next leap of human exploration. Such a bold endeavor will be a driver for an unprecedented worldwide cooperative effort and the catalyst for a new era of international, intercultural and interdisciplinary human relations. Scientific and technological progress will also accelerate as mankind is ushered into a new era of space exploration.

Currently proposed …

Are Wireless Sensors Feasible For Aircraft?, Thomas Yang, Jianhua Liu, Ilteris Demirkiran

Department of Electrical Engineering and Computer Science - Daytona Beach

Wireless communications is a preferred way of data transmission in many aerospace applications. Replacing some aircraft sensor wiring with wireless communications is a highly desirable but challenging transformation. The related sensors are referred to as aerospace wireless sensors (AWSs). This replacement can lower the weight of aircraft wiring, improve the overall safety of aircraft, simplify the design of aircraft structures, and lower the sensor installation and maintenance cost. The major concern for using AWSs is the potential negative effects on overall reliability and safety of aircraft. In this paper, the feasibility of using AWSs is discussed. In particular, the appropriate …

Gossamer Albatross, Steve Elliott

ERAU Prescott Aviation History Program

Steve Elliott was active in the hobby of hang gliding, and was invited to join the Gossamer Albatross team in 1979. He assisted in its development and testing, and was there in a Zodiac raft when it became the first human powered aircraft to cross the English Channel and win the £100,000 Kremer Prize.

A Technology Survey Of Emergency Recovery And Flight Termination Systems For Uas, Richard Stansbury, Wesley Tanis, Timothy Wilson

Publications

For safe flight in the National Airspace System (NAS), either under the current interim rules or under anticipated longer-term regulatory guidelines facilitating unmanned aircraft system (UAS) access to the NAS, the UAS must incorporate technologies and flight procedures to ensure that neither people nor property in the air, on the ground, or on or in the water are endangered by the failure of an onboard component, by inappropriate unmanned aircraft (UA) response to pilot commands, or by inadvertent entry by the UA into prohibited airspace. The aircraft must be equipped with emergency recovery (ER) procedures and technologies that ensure that …

Safety Management Systems Update And Progress, Alan J. Stolzer

Publications

The Safety Management System (SMS) Day Panel Charge on March 18, 2009, delivered by Dr. Alan Stolzer, was intended to provide participants with references, tools, vocabulary, and encouragement to adopt academic and laboratory curricula that would prepare students for careers in the SMS environment.

Molecular Dynamics Study Of Crystal Plasticity During Nanoindentation In Ni Nanowires, V. Dupont, F. Sansoz

Aerospace Engineering - Daytona Beach

Molecular dynamics simulations were performed to gain fundamental insight into crystal plasticity, and its size effects in nanowires deformed by spherical indentation. This work focused on-oriented single-crystal, defect-free Ni nanowires of cylindrical shape with diameters of 12 and 30 nm. The indentation of thin films was also comparatively studied to characterize the influence of free surfaces in the emission and absorption of lattice dislocations in single-crystal Ni. All of the simulations were conducted at 300 K by using a virtual spherical indenter of 18 nm in diameter with a displacement rate of1 ms1. No significant effect of sample size was …

On The Inside Of Spaceshipone, Dan Linehan

ERAU Prescott Aviation History Program

Hear the inside story of the development, testing and flight of the world’s first privately built and piloted manned spacecraft by the author of “SpaceShip One” An Illustrated History”. Exciting photos, videos and animations will help explain how and why all this took place.

Joint Surveillance Target Attack Radar Systems (Joint Stars) --- The Early Days, George Cusimano

ERAU Prescott Aviation History Program

J-STARS is the airborne, battle management radar platform that was such a resounding success during Desert Storm I . Hear the exciting story of the challenges associated with its early development, from the Flight Test Engineer and Mission Commander who was involved from the very start.

Singular Superposition/Boundary Element Method For Reconstruction Of Multi-Dimensional Heat Flux Distributions With Application To Film Cooling Holes, Mahmood Silieti, Eduardo Divo, Alain J. Kassab

Publications

A hybrid singularity superposition/boundary element-based inverse problem method for the reconstruction of multi-dimensional heat flux distributions is developed. Cauchy conditions are imposed at exposed surfaces that are readily reached for measurements while convective boundary conditions are unknown at surfaces that are not amenable to measurements such as the walls of the cooling holes. The purpose of the inverse analysis is to determine the heat flux distribution along cooling hole surfaces. This is accomplished in an iterative process by distributing a set of singularities (sinks) inside the physical boundaries of the cooling hole (usually along cooling hole centerline) with a given …

Invited Article: Data Analysis Of The Floating Potential Measurement Unit Aboard The International Space Station, Aroh Barjatya, Charles M. Swenson, Donald C. Thompson, Kenneth H. Wright

Publications

We present data from the Floating Potential Measurement Unit (FPMU) that is deployed on the starboard truss of the International Space Station. The FPMU is a suite of instruments capable of redundant measurements of various plasma parameters. The instrument suite consists of a floating potential probe, a wide-sweeping spherical Langmuir probe, a narrow-sweeping cylindrical Langmuir probe, and a plasma impedance probe. This paper gives a brief overview of the instrumentation and the received data quality, and then presents the algorithm used to reduce I-V curves to plasma parameters. Several hours of data are presented from August 5, 2006 and March …

Analyzing The Impact Of A Virtual Machine On A Host Machine, Greg Dorn, Chris Marberry, Scott Conrad, Philip Craiger

Publications

As virtualization becomes more prevalent in the enterprise and in personal computing, there is a great need to understand the technology as well as its ramifications for recovering digital evidence. This paper focuses on trace evidence related to the installation and execution of virtual machines (VMs) on a host machine. It provides useful information regarding the types and locations of files installed by VM applications, the processes created by running VMs and the structure and identity of VMs, ancillary files and associated artifacts.

Bluetooth Hacking: A Case Study, Dennis Browning, Gary C. Kessler

Security Studies & International Affairs - Daytona Beach

"This paper describes a student project examining mechanisms with which to attack Bluetooth-enabled devices. The paper briefly describes the protocol architecture of Bluetooth and the Java interface that programmers can use to connect to Bluetooth communication services. Several types of attacks are described, along with a detailed example of two attack tools, Bloover II and BT Info."--from the article