Strain-gage bridge calibration and flight loads measurements on a low-aspect-ratio thin wing

Strain-gage bridges were used to make in-flight measurements of bending moment, shear, and torque loads on a low-aspect-ratio, thin, swept wing having a full depth honeycomb sandwich type structure. Standard regression analysis techniques were employed in the calibration of the strain bridges. Comparison of the measured loads with theoretical loads are included

System analysis and integration studies for a 15-micron horizon radiance measurement experiment

Systems analysis and integration studies for 15-micron horizon radiance measurement experimen

Flight assessment of a large supersonic drone aircraft for research use

An assessment is made of the capabilities of the BQM-34E supersonic drone aircraft as a test bed research vehicle. This assessment is made based on a flight conducted for the purpose of obtaining flight test measurements of wing loads at various maneuver flight conditions. Flight plan preparation, flight simulation, and conduct of the flight test are discussed along with a presentation of the test data obtained and an evaluation of how closely the flight test followed the test plan

Transonic shock-induced dynamics of a flexible wing with a thick circular-arc airfoil

Transonic shock boundary layer oscillations occur on rigid models over a small range of Mach numbers on thick circular-arc airfoils. Extensive tests and analyses of this phenomena have been made in the past but essentially all of them were for rigid models. A simple flexible wing model with an 18 pct. circular arc airfoil was constructed and tested in the Langley Transonic Dynamics Tunnel to study the dynamic characteristics that a wing might have under these circumstances. In the region of shock boundary layer oscillations, buffeting of the first bending mode was obtained. This mode was well separated in frequency from the shock boundary layer oscillations. A limit cycle oscillation was also measured in a third bending like mode, involving wind vertical bending and splitter plate motion, which was in the frequency range of the shock boundary layer oscillations. Several model configurations were tested, and a few potential fixes were investigated

Experimental flutter boundaries with unsteady pressure distributions for the NACA 0012 Benchmark Model

The Structural Dynamics Div. at NASA-Langley has started a wind tunnel activity referred to as the Benchmark Models Program. The objective is to acquire test data that will be useful for developing and evaluating aeroelastic type Computational Fluid Dynamics codes currently in use or under development. The progress is described which was achieved in testing the first model in the Benchmark Models Program. Experimental flutter boundaries are presented for a rigid semispan model (NACA 0012 airfoil section) mounted on a flexible mount system. Also, steady and unsteady pressure measurements taken at the flutter condition are presented. The pressure data were acquired over the entire model chord located at the 60 pct. span station

The benchmark aeroelastic models program: Description and highlights of initial results

An experimental effort was implemented in aeroelasticity called the Benchmark Models Program. The primary purpose of this program is to provide the necessary data to evaluate computational fluid dynamic codes for aeroelastic analysis. It also focuses on increasing the understanding of the physics of unsteady flows and providing data for empirical design. An overview is given of this program and some results obtained in the initial tests are highlighted. The tests that were completed include measurement of unsteady pressures during flutter of rigid wing with a NACA 0012 airfoil section and dynamic response measurements of a flexible rectangular wing with a thick circular arc airfoil undergoing shock boundary layer oscillations

In-Flight Testing of MEMS Pressure Sensors for Flight Loads Determination

The determination and monitoring of structural loads during flight is an important partof every certification program. It must be proved to the certification authorities that the loads occurring during specific flight maneuvers do not exceed the permissible component loads. Usually conventional strain gauges are used to determine structural loads, however an elaborate calibration process is necessary to determine these loads from the measuredstrains. Recent advances in sensor technology allow determining aerodynamic loads directly from pressure distributions measured by MEMS based sensors. When compared to strain gauges this measurement method has several advantages over conventional strain gauges interms of installation and calibration costs. Flight tests were carried out with the DLR researchglider aircraft Discus-2c in order to compare and investigate the loads determined with the two measuring methods. For this purpose a wing glove equipped with 64 MEMS pressure sensors on the airfoil surface was constructed. Different maneuvers with varying loads were performed during the test flights. A first evaluation of steady flight maneuvers shows that theloads determined from the measured pressure distribution are in very good accordance with the ones determined from the strain gauge measurements. This paper gives an overview of the flight test setup and the data analysis process, results from evaluations of trimmed wings-level flight and steady turn maneuvers are presented and discussed

Bolstering Confidence in Obesity Prevention and Treatment Counseling for Resident and Community Pediatricians

Objective- To assess whether equipping resident pediatricians and community pediatricians with both training and practical tools improves their perceived confidence, ease, and frequency of obesity related counseling to patients. Methods- In 2005-2006, resident pediatricians (n = 49) and community pediatricians (n=18) received training regarding three evidence-based obesity prevention/treatment tools and responded to pre-and post-intervention questionnaires. We analyzed changes in reported mean confidence, ease, and frequency of dietary, physical activity, and weight status counseling. Results- Baseline scores of confidence, ease, and frequency of counseling were higher in community pediatricians than residents. Mean scores increased significantly in the combined group, among residents only, and trended towards improvement in the community pediatricians following the intervention. Means for "control" questions were unchanged. Conclusion- Training and tools for residents and community pediatricians improved their confidence, ease, and frequency of obesity-related counseling. Practice Implications- This study demonstrates that when feasible and appropriate tools and training were provided through a simple intervention, physicians gained confidence and ease and increased their counseling frequency. The results here suggest that widespread implementation of such educational interventions for community practitioners and practitioners in training could change the way physicians counsel patients to prevent the often frustrating problem of childhood obesity. Originally published Patient Education and Counseling, Vol. 73, No. 2, Nov 200

Validation of deep learning techniques for quality augmentation in diffusion MRI for clinical studies

The objective of this study is to evaluate the efficacy of deep learning (DL) techniques in improving the quality of diffusion MRI (dMRI) data in clinical applications. The study aims to determine whether the use of artificial intelligence (AI) methods in medical images may result in the loss of critical clinical information and/or the appearance of false information. To assess this, the focus was on the angular resolution of dMRI and a clinical trial was conducted on migraine, specifically between episodic and chronic migraine patients. The number of gradient directions had an impact on white matter analysis results, with statistically significant differences between groups being drastically reduced when using 21 gradient directions instead of the original 61. Fourteen teams from different institutions were tasked to use DL to enhance three diffusion metrics (FA, AD and MD) calculated from data acquired with 21 gradient directions and a b-value of 1000 s/mm2. The goal was to produce results that were comparable to those calculated from 61 gradient directions. The results were evaluated using both standard image quality metrics and Tract-Based Spatial Statistics (TBSS) to compare episodic and chronic migraine patients. The study results suggest that while most DL techniques improved the ability to detect statistical differences between groups, they also led to an increase in false positive. The results showed that there was a constant growth rate of false positives linearly proportional to the new true positives, which highlights the risk of generalization of AI-based tasks when assessing diverse clinical cohorts and training using data from a single group. The methods also showed divergent performance when replicating the original distribution of the data and some exhibited significant bias. In conclusion, extreme caution should be exercised when using AI methods for harmonization or synthesis in clinical studies when processing heterogeneous data in clinical studies, as important information may be altered, even when global metrics such as structural similarity or peak signal-to-noise ratio appear to suggest otherwise