9,562 research outputs found
Neural circuitry at age 6 months associated with later repetitive behavior and sensory responsiveness in autism
Humanizing the Enslaved of Fort Monroe’s Arc of Freedom
Fort Monroe, located in Hampton, Virginia, was a United States Army post until its deactivation in 2011. President Barack Obama proclaimed Fort Monroe a national monument due to its complex history, including its ties to slavery and emancipation. This paper outlines an ongoing research project designed to identify and humanize both the enslaved who helped build the fort and those who were declared as contraband there during the American Civil War. Housed in the National Archives and Records Administration in Philadelphia, Pennsylvania, the United States Army Engineer Records from 1819 to 1866 is the main area of focus for this research project. After reviewing portions of this extensive collection, hundreds of people have been identified by first and last name and further analysis has provided a window into the lives of those who labored and sought refuge at the fort. When completed, the final product from this research will include digitally accessible databases of transcribed documents that will be available to the public at the Fort Monroe Visitor and Education Center. It is hoped that these resources will facilitate additional genealogical connections and help to humanize and commemorate the individuals associated with the Fort Monroe Arc of Freedom
Flight investigation of a vertical-velocity command system for VTOL aircraft
A flight investigation was undertaken to assess the potential benefits afforded by a vertical-velocity command system (VVCS) for VTOL (vertical take-off and landing) aircraft. This augmentation system was conceived primarily as a means of lowering pilot workload during decelerating approaches to a hover and/or landing under category III instrument meteorological conditions. The scope of the investigation included a determination of acceptable system parameters, a visual flight evaluation, and an instrument flight evaluation which employed a 10 deg, decelerating, simulated instrument approach task. The results indicated that the VVCS, which decouples the pitch and vertical degrees of freedom, provides more accurate glide-path tracking and a lower pilot workload than does the unaugmented system
Flight investigation of V/STOL height- control requirements for hovering and low- speed flight under visual conditions
Flight test of V/STOL height control requirement for hovering and low speed flight under visual condition
Convective response of a wall-mounted hot-film sensor in a shock tube
Shock tube experiments were performed in order to determine the response of a single hot-film element of a sensor array to transiently induced flow behind weak normal shock waves. The experiments attempt to isolate the response due only to the change in convective heat transfer at the hot-film surface mounted on the wall of the shock tube. The experiments are described, the results being correlated with transient boundary layer theory and compared with an independent set of experimental results. One of the findings indicates that the change in the air properties (temperature and pressure) precedes the air mass transport, causing an ambiguity in the sensor response to the development of the velocity boundary layer. Also, a transient, local heat transfer coefficient is formulated to be used as a forcing function in an hot-film instrument model and simulation which remains under investigation
Flight investigation of manual and automatic VTOL decelerating instrument approaches and landings
A flight investigation was undertaken to study the problems associated with manual and automatic control of steep, decelerating instrument approaches and landings under simulated instrument conditions. The study was conducted with a research helicopter equipped with a three-cue flight-director indicator. The scope of the investigation included variations in the flight-director control laws, glide-path angle, deceleration profile, and control response characteristics. Investigation of the automatic-control problem resulted in the first automated approach and landing to a predetermined spot ever accomplished with a helicopter. Although well-controlled approaches and landings could be performed manually with the flight-director concept, pilot comments indicated the need for a better display which would more effectively integrate command and situation information
Beam and polarization reconfigurable microstrip antenna based on parasitics
This paper presents a dual‐notch polarization and beam reconfigurable microstrip antenna. It uses parasitics which incorporate switches to steer its beam away from boresight and dual notches which, again, incorporate switches to reconfigure between linear and circular polarization. The antenna is a low profile microstrip patch antenna which only uses a single feed, allowing it to be compact and simple in terms of its structure
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