Development and flight evaluation of an augmented stability active controls concept: Executive summary

A pitch active control system (PACS) was developed and flight tested on a wide body jet transport (L-1011) with a flying horizontal stabilizer. Two dual channel digital computers and the associated software provide command signals to a dual channel series servo which controls the stabilizer power actuators. Input sensor signals to the computer are pitch rate, column trim position, and dynamic pressure. Control laws are given for the PACS and the system architecture is defined. Discussions are given regarding piloted flight simulation and vehicle system simulation and vehicle system simulation tests that are performed to verify control laws and system operation prior to installation on the aircraft. Modifications to the basic aircraft included installation of the PACS, addition of a c.g. management system to provide a c.g. range from 25 to 39% mac, and downrigging of the geared elevator to provide the required nose down control authority for aft c.g. flight test conditions. Three pilots used the Cooper-Harper Rating Scale to judge flying qualities of the aircraft with PACS on and off. The handling qualities with the c.g. at 39% mac (41% stability margin) and PACS operating were judged to be as good as the handling qualities with the c.g. at 25% mac (+15% stability margin) and PACS off

Sonic environment of aircraft structure immersed in a supersonic jet flow stream

Test methods for determining the sonic environment of aircraft structure that is immersed in the flow stream of a high velocity jet or that is subjected to the noise field surrounding the jet, were investigated. Sonic environment test data measured on a SCAT 15-F model in the flow field of Mach 1.5 and 2.5 jets were processed. Narrow band, lateral cross correlation and noise contour plots are presented. Data acquisition and reduction methods are depicted. A computer program for scaling the model data is given that accounts for model size, jet velocity, transducer size, and jet density. Comparisons of scaled model data and full size aircraft data are made for the L-1011, S-3A, and a V/STOL lower surface blowing concept. Sonic environment predictions are made for an engine-over-the-wing SST configuration

Children's body mass index, participation in school meals, and observed energy intake at school meals

<p>Abstract</p> <p>Background</p> <p>Data from a dietary-reporting validation study with fourth-grade children were analyzed to investigate a possible relationship of body mass index (BMI) with daily participation in school meals and observed energy intake at school meals, and whether the relationships differed by breakfast location (classroom; cafeteria).</p> <p>Methods</p> <p>Data were collected in 17, 17, and 8 schools during three school years. For the three years, six, six, and seven of the schools had breakfast in the classroom; all other schools had breakfast in the cafeteria. Information about 180 days of school breakfast and school lunch participation during fourth grade for each of 1,571 children (90% Black; 53% girls) was available in electronic administrative records from the school district. Children were weighed and measured, and BMI was calculated. Each of a subset of 465 children (95% Black; 49% girls) was observed eating school breakfast and school lunch on the same day. Mixed-effects regression was conducted with BMI as the dependent variable and school as the random effect; independent variables were breakfast participation, lunch participation, combined participation (breakfast and lunch on the same day), average observed energy intake for breakfast, average observed energy intake for lunch, sex, age, breakfast location, and school year. Analyses were repeated for BMI category (underweight/healthy weight; overweight; obese; severely obese) using pooled ordered logistic regression models that excluded sex and age.</p> <p>Results</p> <p>Breakfast participation, lunch participation, and combined participation were not significantly associated with BMI or BMI category irrespective of whether the model included observed energy intake at school meals. Observed energy intake at school meals was significantly and positively associated with BMI and BMI category. For the total sample and subset, breakfast location was significantly associated with BMI; average BMI was larger for children with breakfast in the classroom than in the cafeteria. Significantly more kilocalories were observed eaten at breakfast in the classroom than in the cafeteria.</p> <p>Conclusions</p> <p>For fourth-grade children, results provide evidence of a positive relationship between BMI and observed energy intake at school meals, and between BMI and school breakfast in the classroom; however, BMI and participation in school meals were not significantly associated.</p

Logarithmic perturbation theory for quasinormal modes

Logarithmic perturbation theory (LPT) is developed and applied to quasinormal modes (QNMs) in open systems. QNMs often do not form a complete set, so LPT is especially convenient because summation over a complete set of unperturbed states is not required. Attention is paid to potentials with exponential tails, and the example of a Poschl-Teller potential is briefly discussed. A numerical method is developed that handles the exponentially large wavefunctions which appear in dealing with QNMs.Comment: 24 pages, 4 Postscript figures, uses ioplppt.sty and epsfig.st

Black Hole Decay and Quantum Instantons

We study the analytic structure of the S-matrix which is obtained from the reduced Wheeler-DeWitt wave function describing spherically symmetric gravitational collapse of massless scalar fields. The complex simple poles in the S-matrix lead to the wave functions that satisfy the same boundary condition as quasi-normal modes of a black hole, and correspond to the bounded states of the Euclidean Wheeler-DeWitt equation. These wave function are interpreted as quantum instantons.Comment: RevTex, 7 pages, no figure; The wave functions of gr-qc/9912115 are newly interpreted as quantum instantons describing a black hole decay. Replaced by the version to be published in Phys. Rev. D, in which the boundary condition on the apparent horizon is clarifie

Antarctic atmospheric boundary layer observations with the Small Unmanned Meteorological Observer (SUMO)

Between&nbsp;January&nbsp;2012 and June&nbsp;2017 a small unmanned aerial system (sUAS), known as the Small Unmanned Meteorological Observer (SUMO), was used to observe the state of the atmospheric boundary layer in the Antarctic. During six Antarctic field campaigns, 116 SUMO flights were completed. These flights took place during all seasons over both permanent ice and ice-free locations on the Antarctic continent and over sea ice in the western Ross Sea. Sampling was completed during spiral ascent and descent flight paths that observed the temperature, humidity, pressure and wind up to 1000&thinsp;m above ground level and sampled the entire depth of the atmospheric boundary layer, as well as portions of the free atmosphere above the boundary layer. A wide variety of boundary layer states were observed, including very shallow, strongly stable conditions during the Antarctic winter and deep, convective conditions over ice-free locations in the summer. The Antarctic atmospheric boundary layer data collected by the SUMO sUAS, described in this paper, can be retrieved from the United States Antarctic Program Data Center (https://www.usap-dc.org, last access: 8&nbsp;March&nbsp;2021). The data for all flights conducted on the continent are available at https://doi.org/10.15784/601054 (Cassano, 2017), and data from the Ross Sea flights are available at https://doi.org/10.15784/601191 (Cassano, 2019). </div

Contamination Control and Assay Results for the Majorana Demonstrator Ultra Clean Components

The MAJORANA DEMONSTRATOR is a neutrinoless double beta decay experiment utilizing enriched Ge-76 detectors in 2 separate modules inside of a common solid shield at the Sanford Underground Research Facility. The DEMONSTRATOR has utilized world leading assay sensitivities to develop clean materials and processes for producing ultra-pure copper and plastic components. This experiment is now operating, and initial data provide new insights into the success of cleaning and processing. Post production copper assays after the completion of Module 1 showed an increase in U and Th contamination in finished parts compared to starting bulk material. A revised cleaning method and additional round of surface contamination studies prior to Module 2 construction have provided evidence that more rigorous process control can reduce surface contamination. This article describes the assay results and discuss further studies to take advantage of assay capabilities for the purpose of maintaining ultra clean fabrication and process design.Comment: Proceedings of Low Radioactivity Techniques (LRT May 2017, Seoul