Moving-base visual simulation study of decoupled controls during approach and landing of a STOL transport aircraft

The simulation employed all six rigid-body degrees of freedom and incorporated aerodynamic characteristics based on wind-tunnel data. The flight instrumentation included a localizer and a flight director which was used to capture and to maintain a two-segment glide slope. A closed-circuit television display of a STOLport provided visual cues during simulations of the approach and landing. The decoupled longitudinal controls used constant prefilter and feedback gains to provide steady-state decoupling of flight-path angle, pitch angle, and forward velocity. The pilots were enthusiastic about the decoupled longitudinal controls and believed that the simulator motion was an aid in evaluating the decoupled controls, although a minimum turbulence level with root-mean-square gust intensity of 0.3 m/sec (1 ft/sec) was required to mask undesirable characteristics of the moving-base simulator

THE FEDERAL CROP INSURANCE PROGRAM - AN EMPIRICAL ANALYSIS OF REGIONAL DIFFERENCES IN ACREAGE RESPONSE AND PARTICIPATION

The extent to which crop insurance programs have resulted in additional land being brought into production has been a topic of considerable debate. We extend a multi-equation structural model of crop acreage response, insurance participation, CRP enrollment, and input usage developed in Goodwin and Vandeveer (2000) to wheat and barley production in the "Northern Great Plains" region. We also update earlier results for corn and soybean production in the "Heartland" region. Our results confirm earlier findings that increased participation in insurance programs provoke a statistically significant acreage response. This response is, however, relatively modest. We find that cross-the-board decreases of 50% in insurance premiums significantly increase participation but result in acreage increases of about 0.5% for barley and 3.7% for wheat. In the modern period (1997-1998),expanded insurance participation brought about by premium rate reductions has almost no effect on acreage. Our results for the recent period show a shifting in coverage toward revenue insurance.Crop Production/Industries, Risk and Uncertainty,

Life History of Hemlock Woolly Adelgid, \u3cem\u3eAdelges tsugae\u3c/em\u3e Annand, on Eastern Hemlock, \u3cem\u3eTsuga canadensis\u3c/em\u3e (L.) Carriere, in the Southern Appalachians and Assessment of Egg Releases of \u3cem\u3eSasajiscymnus tsugae\u3c/em\u3e (Sasaji and McClure) for Its Management

Studies were conducted in 2005 and 2006 at Baxter Orchard, Great Smoky Mountains National Park, Tennessee to optimize survival of Sasajiscymnus tsugae (St) (Sasaji and McClure) released as eggs on eastern hemlock, Tsuga canadensis (L.) Carriere, for biological control of Adelges tsugae (HWA) Annand. Studies investigated annual abundance and seasonality of HWA lifestages, weekly field and laboratory survival of St, and survival of St egg cohorts of various ages and densities. HWA was determined to be bivoltine on eastern hemlock in Tennessee with an aestivation period between July and October. Lifestages preferred as food by St were present from February through June with peak abundance ca. late March. Weekly survival of St placed in the field and laboratory as eggs was investigated. Less than 10% of St eggs placed in the field between 8 February to 22 March survived because of freezing field temperatures. Survival rose to 30-40% on 30 March and persisted at that level until 7 June, when survival decreased below 10% due to scarcity of food. Studies were conducted to investigate the effect of St egg density on survival of St. Four densities of St eggs (50, 100, 150, and 200 eggs/container) were placed in the field and laboratory. In the laboratory, survival was higher for lower densities of St eggs, implying cannibalism increases with density. Three egg age classes (0-2, 3-5, and 6-8 days old) were used to test the effect of St egg age on survival. St in field cages showed poor survival, likely due to freezing temperatures. However, the oldest (6-8 day) age class showed significantly greater survival in the field than the younger age classes. The two oldest age classes showed significantly greater survival than the youngest (0-2 day) age class in the laboratory. Results of multiple studies over two years support the release of St eggs to enhance biological control efforts against HWA. Studies showed St established as eggs in the field could successfully develop into adults. Survival of St from egg releases is highest when St eggs are released between late March and May, in low densities, and in older age classes

Fixed-base simulation study of decoupled controls during approach and landing of a STOL transport airplane

A fixed-base visual simulation study has been conducted to evaluate the use of decoupled controls as a means for reducing pilot workload during approach and landing of an externally blown jet-flap short take-off and landing (STOL) transport. All six rigid-body degrees of freedom were employed with the aerodynamic characteristics based on wind-tunnel data. The primary piloting task was to use a flight director to capture and maintain a two-segment glide slope, with a closed-circuit television display of a STOL airport used during simulations of the flare and landing. The decoupled longitudinal controls used constant prefilter and feedback gains to provide steady-state decoupling of flight-path angle, pitch angle, and forward velocity. The pilots were enthusiastic about the decoupled longitudinal controls but believed the decoupled concept offered no significant advantage over conventional controls in the lateral mode

Simulator study of stall/post-stall characteristics of a fighter airplane with relaxed longitudinal static stability

A real-time piloted simulation was conducted to evaluate the high-angle-of-attack characteristics of a fighter configuration based on wind-tunnel testing of the F-16, with particular emphasis on the effects of various levels of relaxed longitudinal static stability. The aerodynamic data used in the simulation was conducted on the Langley differential maneuvering simulator, and the evaluation involved representative low-speed combat maneuvering. Results of the investigation show that the airplane with the basic control system was resistant to the classical yaw departure; however, it was susceptible to pitch departures induced by inertia coupling during rapid, large-amplitude rolls at low airspeed. The airplane also exhibited a deep-stall trim which could be flown into and from which it was difficult to recover. Control-system modifications were developed which greatly decreased the airplane susceptibility to the inertia-coupling departure and which provided a reliable means for recovering from the deep stall

SWIRP (Submm-Wave and Long Wave InfraRed Polarimeter); Development and Characterization of a Sub-Mm Polarimeter for Ice Cloud Investigations

A major source of uncertainty in climate models is the presence, shape and distribution of ice particles in the uppermost layers of the clouds. The effects of this component are poorly constrained, turning ice particles into an almost-free variable in many climate models.NASA-GSFC is developing a new instrument aimed at measuring the size and shape of ice particles. The instrument consists of two sub-mm polarimeters (at 220 and 670 GHz) coupled with a long-wave infrared polarimeter at 10 micron. Each polarimeter has identical V-pol and H-pol channels; the axes of polarization are defined geometrically by the orientation of the waveguide elements, and the purity has been measured in the lab. The instrument is configured as a conical scanner, suitable for deployment as a payload on a small satellite or on a high-altitude sub-orbital platform. From a 400 km orbit, the instrument has a 3dB spatial resolution of 20 (10) km at 220 (670) GHz and a swath of 600 km over 180 degrees of view.The BAPTA (Bearing And Power Transfer Assembly) carries heritage from the SSMIS design, now in its 22nd year of on-orbit operation, but with a much reduced SWaP (Size Weight and Power) footprint, suitable for a small satellite.The main components of the instrument have been fabricated and are undergoing final testing prior to their integration as a single unit. The sub-mm channels have dedicated secondary reflectors which illuminate a shared primary reflector. The receiving units are placed behind the focal point of the optical arrangement, so that all beams equally illuminate the primary reflector and are almost co-located on the ground (within a single 220 GHz footprint). Primary and secondary beam patterns have been measured and verified to match the as-designed expectations. A Zytex (TM) window is deployed to protect the secondary reflectors and the feed horns from debris and other contaminants, and to reduce the heat load from the active (hot) IR calibration unit. The insertion loss of Zytex has been measured and is accounted in the calibration equation of the sub-mm channels.The radiometric performance of the sub-mm receivers has been characterized in the lab and under operational conditions of temperature and pressure.This paper discusses the design constraints on the sub-mm components, details of the scientific goals and their flowdown, and describes the characterization of the polarimeters. Options to optimize the layout and distribution of the masses within the assembly, with the goal of making the instrument even more compact and fully-compatible with cubesat-class satellites will be presented

Research as Inquiry: A Discipline Specific Approach to Information Literacy

https://aquila.usm.edu/textbooks/1003/thumbnail.jp

Research as Inquiry: A Discipline Specific Approach to Information Literacy

https://aquila.usm.edu/textbooks/1003/thumbnail.jp

Collaboration during a crisis - the Lighthouse Lab volunteers.

As a group of early-career researchers, we recount our experiences of volunteering at one of the national Lighthouse Labs based at the UK Biocentre in Milton Keynes. We worked together as part of a multidisciplinary team to support the large-scale processing of coronavirus disease 2019 (COVID-19) swabs from across the whole of the UK