213 research outputs found
Six Degree of Freedom Morphing Aircraft Dynamical Model with Aerodynamics
Morphing aircraft are envisioned to have multirole capability where the ability
to change shape allows for adaptation to a changing mission environment. In order to
calculate the properties of many wing configurations efficiently and rapidly, a model
of a morphing aircraft is needed. This paper develops an aerodynamic model and
a dynamic model of a morphing
flying wing aircraft. The dynamic model includes
realistic aerodynamic forces, consisting of lift, drag, and pitching moment about the
leading edge, calculated using a constant strength source doublet panel method. The
panel method allows for the calculation of aerodynamic forces due to large scale
shape changing effects. The aerodynamic model allows for asymmetric configurations
in order to generate rolling and yawing moments. The dynamic model calculates
state information for the morphing wing based on the aerodynamic forces from the
panel method. The model allows for multiple shape changing degrees-of-freedom
for the wing, including thickness, sweep, dihedral angle, and chord length. Results
show the model provides a versatile and computationally efficient tool for calculating
the aerodynamic forces on the morphing aircraft and using these forces to show the
associated states
Garbage, Garbage Everywhere!
Grade Level(s): 9-12In order to get students to see that they can do simple things to help the environment, a study of the relationship between trash/garbage and soil will be undertaken.La Porte High School; La Porte, Indian
Data user's note: Apollo 15 lunar photography
Brief descriptions are given of the Apollo 15 mission objectives, photographic equipment, and photographic coverage and quality. The lunar photographic tasks were: (1) ultraviolet photography of the earth and moon; (2) photography of the gegenschein from lunar orbit; (3) service module orbital photographic tasks; and (4) command module photographic tasks
The Strategic Challenges of Urban Warfare
With urbanization on the rise, policymakers cannot ignore urban conflicts. In the aftermath of the Cold War, several scholars were of the opinion that primitive modes of fighting, such as close combat, would cease to be used. However, as urban spaces have increasingly become battlefields in the 21st century, there has been a retrogression to a brutal and bloody mode of fighting. This return of primitivism affects the tactics that the military can use in urban warfare, which makes it a daunting strategic challenge. A combined focus on policy, strategy, and operations is necessary to improve thinking about how exactly to engage in urban warfare. Since this is a low-tech military problem, high-tech advances do not provide viable solutions. Israel\u27s Operation Protective Edge and the joint Iraqi and American fight for eastern Mosul are assessed in this thesis in their policy, strategy, and operational dimensions. Finally, I present conclusions and recommendations suggesting that we concentrate on honing our capabilities and knowledge in order to successfully engage in urban warfare while staying true to liberal democratic values. Such an approach will provide policymakers with more strategic options for dealing with urban warfare
Japanese Attitudes Toward Defense and Security Issues
Since President Nixon enunciated the Guam Doctrine in 1969, Japanese defense policy has emerged as a major issue in US relations with Japan
Electron barrier interaction in a vacuum tunneling probe
A model for dealing with energy and momentum exchanges between ballistic
electrons in a vacuum barrier in a tunneling probe used as an electromechanical
transducer is studied and its physical significance in devices of size
comparable to the mean free path of the tunneling electrons is discusse
Observation of Modulated Quadrupolar Structures in PrPb3
Neutron diffraction measurements have been performed on the cubic compound
PrPb3 in a [001] magnetic field to examine the quadrupolar ordering.
Antiferromagnetic components with q=(1/2+-d 1/2 0), (1/2 1/2+-d 0) (d~1/8) are
observed below the transition temperature TQ (0.4 K at H=0) whose amplitudes
vary linear with H and vanish at zero field, providing the first evidence for a
modulated quadrupolar phase. For H<1 T, a non-square modulated state persists
even below 100 mK suggesting quadrupole moments associated with a Gamma3
doublet ground state to be partially quenched by hybridization with conduction
electrons.Comment: Physical Review Letters, in press. 4 pages, 4 figure
Six Degree of Freedom Morphing Aircraft Dynamical Model with Aerodynamics
Morphing aircraft are envisioned to have multirole capability where the ability
to change shape allows for adaptation to a changing mission environment. In order to
calculate the properties of many wing configurations efficiently and rapidly, a model
of a morphing aircraft is needed. This paper develops an aerodynamic model and
a dynamic model of a morphing
flying wing aircraft. The dynamic model includes
realistic aerodynamic forces, consisting of lift, drag, and pitching moment about the
leading edge, calculated using a constant strength source doublet panel method. The
panel method allows for the calculation of aerodynamic forces due to large scale
shape changing effects. The aerodynamic model allows for asymmetric configurations
in order to generate rolling and yawing moments. The dynamic model calculates
state information for the morphing wing based on the aerodynamic forces from the
panel method. The model allows for multiple shape changing degrees-of-freedom
for the wing, including thickness, sweep, dihedral angle, and chord length. Results
show the model provides a versatile and computationally efficient tool for calculating
the aerodynamic forces on the morphing aircraft and using these forces to show the
associated states
A computational approach for understanding adaptation in vertebrate hair cells
Thesis (Ph. D.)--Harvard-MIT Program in Health Sciences and Technology, 2012.Pages 157 and 158 blank. Cataloged from PDF version of thesis.Includes bibliographical references (p. 150-156).Vertebrate hair cells respond to mechanical stimuli with an inward current that is carried by extracellular cations through mechanically-gated transmembrane ion channels called transduction channels, located in the hair cell's specialized apical surface called the stereocilia. The current is characterized as having a rapid onset and adapting exponentially with a fast and slow time constant. The fast component is usually attributed to calcium binding directly to the transduction channels to promote channel reclosure. Myosin-1C, an unconventional myosin motor protein that is also modulated by calcium, adjusts the tension applied to the transduction channel to cause slow adaptation. Neither adaptation typically acts completely to restore the transduction current back to the baseline level. Recent evidence has suggested that the transduction channel is further away from myosin-IC than previously believed, creating a spatial separation that changes the nature of the calcium feedback. I developed a computational model to explore the motion of vertebrate hair cells simultaneously with calcium diffusion within the cell. The model is also capable of simulating many other experimental techniques that are commonly applied to hair cells. The results of the model suggest a fundamentally different viewpoint for understanding adaptation in vertebrate hair cells. Calcium can create unique responses from different transduction channels within the same hair cell. The implications of these findings help to explain the incompleteness of adaptation as well as implicate myosin-1C for fast adaptation as well as slow adaptation. In addition, groundwork for better understanding stereocilia-based amplification in the mammalian cochlea was developed. Experimental predictions were created to test these theories.by Paul D. Niksch.Ph.D
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