Upgrading of NASA-Ames high-energy hypersonic facilities: A Study

This study reviews facility capabilities of NASA, Ames Research Center to simulate hypersonic flight with particular emphasis on arc heaters. Scaling laws are developed and compared with ARCFLO II calculations and with existing data. The calculations indicate that a 300 MW, 100 atmosphere arc heater is feasible. Recommendations for the arc heater, which will operate at voltages up to 50 kilovolts, and the associated elements needed for a test facility are included

Electric arc apparatus Patent

Electric arc heater with supersonic nozzle and fixed arc length for use in high temperature wind tunnel

The Texas Spoofing Test Battery: Toward a Standard for Evaluating GPS Signal Authentication Techniques

A battery of recorded spoofing scenarios has been compiled for evaluating civil Global Positioning System (GPS) signal authentication techniques. The battery can be considered the data component of an evolving standard meant to define the notion of spoof resistance for commercial GPS receivers. The setup used to record the scenarios is described. A detailed description of each scenario reveals readily detectable anomalies that spoofing detectors could target to improve GPS securityAerospace Engineering and Engineering Mechanic

A Testbed for Developing and Evaluating GNSS Signal Authentication Techniques

An experimental testbed has been created for developing and evaluating Global Navigation Satellite System (GNSS) signal authentication techniques. The testbed advances the state of the art in GNSS signal authentication by subjecting candidate techniques to the strongest publicly-acknowledged GNSS spoofing attacks. The testbed consists of a real-time phase-coherent GNSS signal simulator that acts as spoofer, a real-time softwaredefined GNSS receiver that plays the role of defender, and post-processing versions of both the spoofer and defender. Two recently-proposed authentication techniques are analytically and experimentally evaluated: (1) a defense based on anomalous received power in a GNSS band, and (2) a cryptographic defense against estimation-and-replay-type spoofing attacks. The evaluation reveals weaknesses in both techniques; nonetheless, both significantly complicate a successful GNSS spoofing attackAerospace Engineering and Engineering Mechanic

Paper Session II-C - SPACEHAB: Accommodations For Commercial Microgravity Experimentation

The August 1992 flight of the first SPACEHAB module aboard the Space Shuttle initiates a new era of opportunity for commercial experimentation in a pressurized, crew-tended, microgravity environment. The SPACEHAB module\u27s flexible design allows tailoring of each mission\u27s payload complement to maximize the number of experiments flown within the 3000 pound total payload capacity. Up to 71 lockers, or 51 lockers and 2 racks may be integrated in the module. Two crewmen can perform tasks simultaneously; and a full service Command and Data Management System and Environmental Control System are available to support experiments. In addition to the physical accommodations, a broad spectrum of technical support services are available to provide a user friendly integration process. Spacehab is here to provide your space in Space

Faithful Magistrates and Republican Lawyers: Creators of Virginia\u27s Legal Culture, 1680-1810

That well-known but inadequately understood institution, the county court, was brought to life and placed in clear perspective as an integral part of the life of colonists of every variety of status and calling nearly thirty years ago in Charles Sydnor\u27s classic, albeit impressionistic, study, Gentlemen Freeholders: Political Practices in Washington\u27s Virginia (1952). Sydnor proclaimed that in eighteenth-century Virginia planters, not lawyers, dominated the political scene and thus dispensed with the legal profession. Sydnor\u27s domain was politics; his discussion centered on the county oligarchies. In recent years scholars have recognized the pressing need for a deeper understanding of the operations and impact of the early Virginia bench and bar. To answer this need for research which will take us through the door Sydnor opened but beyond which he only peered, we now have, in A. G. Roeber\u27s new book, a well-crafted guide to this relatively uncharted territory of the Old Dominion\u27s legal history

Census of Law Books in Colonial Virginia By William Hamilton Bryson

A decade ago Stanley Katz asserted that the eighteenth century American lawyer exhibited a surprising familiarity with contemporary English law and a high degree of technical competence, and challenged legal historians to reappraise traditional views of the colonial bar. To a great extent this task has been undertaken, but the legal history of early Virginia still languishes. Anxious to rectify this situation, Professor W. Hamilton Bryson of the University of Richmond School of Law has compiled a census of law books in early Virginia, hoping to shed some light on the law which shaped the lawyers who shaped the nation

Application of Hapke photometric model to three geologic surfaces using PARABOLA bidirectional reflection data

The Geologic Remote Sensing Field Experiment (GRSFE) was conducted in July and September of 1989 to collect data with both ground and airborne instrumentation. A major objective of GRSFE was to collect data which could be used to test radiative transfer models for the extraction of composition and textural surface properties from remotely acquired data. Reported here are the initial results from an application of the Hapke photometric model, using data from the Portable Apparatus for Remote Acquisition of Bidirectional Observations of Land and Atmosphere (PARABOLA), a ground based radiometer with three spectral channels. PARABOLA data was collected in the Lunar Crater Volcanic Field in Nevada, specifically from the region of Lunar Lake, a playa. The Hapke model was found to be inadequate for three relatively common geologic surfaces (a clay-rich, hard packed surface with decimeter sized mudcracks; a cobble site, similar to a playa site, but strewn with basaltic cobbles and pebbles; and a surface mantled basalt lava flow). The model is not at fault; rather, the complexity of most geologic surfaces is not accounted for in the initial assumptions

TB149: Wood Property-Age Relationships of Natural and Plantation-Grown Red Pine

This study examined changes in specific gravity, modulus of rupture, and modulus of elasticity with age for a natural stand and two plantations. It also examined differences in wood properties between the three stands and the effects of important variables on, and their interactions with, wood properties. Wood property data were obtained from microbending specimens selected at breast height from five trees in each stand.https://digitalcommons.library.umaine.edu/aes_techbulletin/1049/thumbnail.jp