157 research outputs found
Design of a Mechanical Model for Pulsatile Aortic Flow
This project developed a mechanical model for simulating blood flow through the abdominal aorta and iliac arteries. Artificial artery systems were constructed to simulate healthy and diseased states. Measurements of the flow were taken to determine if a change in pressure between states was statistically significant. Data was obtained through LabView and waveform analysis conducted with the Fast Fourier Transform. The ultimate goal of the project was to assess the feasibility of a non-invasive procedure to diagnose early stage atherosclerosis
Blade-Mounted Flap Control for BVI Noise Reduction Proof-of-Concept Test
This report describes a wind tunnel test of the McDonnell Douglas Helicopter Systems (MDHS) Active Flap Model Rotor at the NASA Langley 14- by 22-Foot Subsonic Tunnel. The test demonstrated that BVI noise reductions and vibration reductions were possible with the use of an active flap. Aerodynamic results supported the acoustic data trends, showing a reduction in the strength of the tip vortex with the deflection of the flap. Acoustic results showed that the flap deployment, depending on the peak deflection angle and azimuthal shift in its deployment schedule, can produce BVI noise reductions as much as 6 dB on the advancing and retreating sides. The noise reduction was accompanied by an increase in low frequency harmonic noise and high frequency broadband noise. A brief assessment of the effect of the flap on vibration showed that significant reductions were possible. The greatest vibration reductions (as much as 76%) were found in the four per rev pitching moment at the hub. Performance improvement cam results were inconclusive, as the improvements were predicted to be smaller than the resolution of the rotor balance
Biomechanical modelling of the whole human spine for dynamic analysis
Developing computational models of the human spine has been a hot topic in
biornechanical research for a couple of decades in order to have an
understanding of the behaviour of the whole spine and the individual spinal
parts under various loading conditions. The objectives of this thesis are to
develop a biofidefic multi-body model of the whole human spine especially for
dynamic analysis of impact situations, such as frontal impact in a car crash, and
to generate finite element (FE) models of the specific spinal parts to investigate
causes of injury of the spinal components. As a proposed approach, the
predictions of the multi-body model under dynamic impact loading conditions,
such as reaction forces at lumbar motion segments, were utilised not only to
have a better understanding of the gross kinetics and kinematics of the human
spine, but also to constitute the boundary conditions for the finite element
models of the selected spinal components. This novel approach provides a
versatile, cost effective and powerful tool to analyse the behaviour of the spine
under various loading conditions which in turn helps to develop a better understanding of injury mechanisms
Sensors for ceramic components in advanced propulsion systems: Summary of literature survey and concept analysis, task 3 report
The results of a literature survey and concept analysis related to sensing techniques for measuring of surface temperature, strain, and heat flux for (non-specific) ceramic materials exposed to elevated temperatures (to 2200 K) are summarized. Concepts capable of functioning in a gas turbine hot section environment are favored but others are reviewed also. Recommendation are made for sensor development in each of the three areas
Advanced Knowledge Application in Practice
The integration and interdependency of the world economy leads towards the creation of a global market that offers more opportunities, but is also more complex and competitive than ever before. Therefore widespread research activity is necessary if one is to remain successful on the market. This book is the result of research and development activities from a number of researchers worldwide, covering concrete fields of research
NASA Tech Briefs, March 1992
Topics include: New Product Ideas; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences
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