• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 123
  • 22
  • 15
  • 13
  • 11
  • 7
  • 3
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 251
  • 47
  • 38
  • 21
  • 20
  • 19
  • 18
  • 18
  • 17
  • 16
  • 16
  • 16
  • 15
  • 14
  • 14
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Design of Controller board for a Lunar Rover

Rejas, Marcos January 2010 (has links)
<p>The Lunar Rover (Roony) is a robotic project group at Mälardalens University composed by students. The objective of this group is to design and build an autonomous robot that has to be able to move by itself through the moon terrain.</p><p>The Lunar Rover is divided in several sub-projects from different knowledge areas; the objective of this electronic thesis is to design a controller board.</p><p> </p><p>The designed board will be able to connect the robot to an external dispositive (via JTAG, or WIFI), and also it will control and connect the different robot’s peripherals.</p><p>The main component of the controller board is the microcontroller AT90CAN128.</p><p>The peripherals are a steeper motor, a LIDAR system (Light Detection And Ranging), a WIFI chip(WIPORT™), a bus can driver, an accelerometer, a LIPO( Lithium-Ion Polymer) battery charger, a Solar photovoltaic cell handler, and sixteen DC motors(four in each leg of the robot).</p><p>Once the logic design has finished, the PCB design is done attending the size limitations of the robot. Once the design has finished, a prototype has been built and tested using ATMEL software.</p>
32

Hybrid simulation of the interaction of solar wind protons with a concentrated lunar magnetic anomaly

Giacalone, J., Hood, L. L. 06 1900 (has links)
Using a two-dimensional hybrid simulation, we study the physics of the interaction of the solar wind with a localized magnetic field concentration, or “magcon,” on the Moon. Our simulation treats the solar wind protons kinetically and the electrons as a charge-neutralizing fluid. This approach is necessary because the characteristic scale of the magcon is of the same order or smaller than the proton inertial length—the characteristic scale in the hybrid simulation. Specifically, we consider a case in which the incident solar wind flows exactly normal to the lunar surface, and the magcon is represented by a simple dipole whose moment is parallel to the surface, with a center just below it. We find that while the magcon causes the solar wind to be deflected and decelerated, it does not completely shield the lunar surface anywhere. However, protons which impact the surface in the center of the magnetic anomaly have energies well below the solar wind ram energy. Thus, in this region, any backscattered neutral particles resulting from the interaction of solar wind protons with the lunar regolith would have energies lower than that of the solar wind. Moreover, very few neutrals, if any, would emanate from within the magcon with energies comparable to the solar wind energy. This may explain recent observations of lunar energetic neutral atoms associated with a strong crustal magnetic anomaly. Our study also finds that a significant fraction of the incoming solar wind protons are reflected back into space before reaching the surface. These particles are reflected by a strong electrostatic field which results from the difference in the proton and electron inertia. The reflected particles are seen at very high altitudes above the Moon, over 200 km, and over a much broader spatial scale than the magcon, several hundred kilometers at least. Our simulation also revealed a second population of reflected particles which originate from the side of the magcon where the interplanetary and magcon magnetic fields are directed opposite to one another, leading to a magnetic topology much like magnetic reconnection. As previously reflected particles move through this region, they are deflected upward, away from the surface, forming a second component. Our simulation has a number of similarities to recent in situ spacecraft observations of reflected ions above and around magcons.
33

Introducing the moon to South African natural science classrooms

Kelfkens, Lesley 08 April 2009 (has links)
This dissertation concerns the the problem that natural science teachers with limited astronomy backgrounds have to teach new curriculum content about lunar motion, phases and eclipses. My study aims to establish: 60 teachers’ knowledge of lunar phenomena through surveys; whether an intervention incorporating models and activities is effective at improving a case study group’s understandings; how the case study teachers use these activities and models in the classroom. My results indicate that the majority of natural science teachers have little formal astronomy education. Only two teachers held a scientific understanding of lunar phenomena. The intervention led towards a more scientific understanding amongst the case study group. Scale is essential for developing an understanding of lunar phenomena and models are extremely beneficial, but participants experience spatial problems when viewing models from an external perspective. I propose in-service training in small groups for building knowledge and increasing confidence for teaching this content.
34

Magnetism and geology of the moon

Tiedeken, Staci L. 01 January 2017 (has links)
Since different parts of the Moon display varying magnetic field strengths, our goal was to determine whether these differences are due to specific geological characteristics. We found that older materials tend to be more magnetic than younger materials. Additional statistical studies found that the mare regions of the Moon are less magnetic than the plains and terra regions. We did not find a simple relationship between lunar magnetism and crustal thickness, and this is inconsistent with the hypothesis that thicker crust is more magnetic since there is additional material. Thus, it is not just a matter of the amount of magnetic material that determines the magnetic field strength of the lunar crust. Our results demonstrate that magnetism and crustal thickness have a complex relationship, with multiple distinct groups corresponding to various regions of the Moon. The lunar maria formed a particularly distinct group, consisting of low magnetism and thin crust, while the lunar highlands consist of thick crust but typical magnetic field values. The ejecta thickness and magnetic field distributions for specific craters showed that larger impact basins have a thicker and more widespread ejecta blanket than smaller craters. We did not find a consistent pattern of magnetic field enhancements near specific craters, but evidence for these strong magnetic signatures was present for Mare Crisium and Mare Nectaris. These results may support the hypothesis that ejecta materials are carriers of magnetism, and this may be the reason for their tendency to have higher magnetic field strengths.
35

Comparison of track reconstruction algorithms for the Moon Shadow Analysis in IceCube

Kim, Kwang Seong January 2013 (has links)
No description available.
36

Design of Controller board for a Lunar Rover

Rejas, Marcos January 2010 (has links)
The Lunar Rover (Roony) is a robotic project group at Mälardalens University composed by students. The objective of this group is to design and build an autonomous robot that has to be able to move by itself through the moon terrain. The Lunar Rover is divided in several sub-projects from different knowledge areas; the objective of this electronic thesis is to design a controller board.   The designed board will be able to connect the robot to an external dispositive (via JTAG, or WIFI), and also it will control and connect the different robot’s peripherals. The main component of the controller board is the microcontroller AT90CAN128. The peripherals are a steeper motor, a LIDAR system (Light Detection And Ranging), a WIFI chip(WIPORT™), a bus can driver, an accelerometer, a LIPO( Lithium-Ion Polymer) battery charger, a Solar photovoltaic cell handler, and sixteen DC motors(four in each leg of the robot). Once the logic design has finished, the PCB design is done attending the size limitations of the robot. Once the design has finished, a prototype has been built and tested using ATMEL software.
37

Fluid and particle simulations of the interaction of the solar wind with magnetic anomalies on the surface of the Moon and Mars /

Harnett, Erika Megan. January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 133-140).
38

Stratigraphy and structure of the Cleomedes quadrangle of the moon

Binder, Alan Bruce, 1939- January 1967 (has links)
No description available.
39

Infrared colorimetry of the moon

Cruikshank, Dale P. January 1968 (has links)
No description available.
40

Lunar Surface Geology From Analysis of Impact Craters and Their Ejecta

Bart, Gwendolyn Diane January 2007 (has links)
Analysis of impact craters and their ejecta addresses someunanswered questions about the lunar surface. First I estimatethe regolith depth on the south farside of the Moon to be about40 m, which is significantly deeper than the nearside regolith,estimated to be 3-16 m. This result is obtained by studyinghundred meter diameter flat floored craters, using the method ofQuaide and Oberbeck (J. Geophys. Res., 1968, 73, 5247-5270). This measurement has implications for the formation of the lunarregolith, and for interpretation of samples returned in thefuture by astronauts or automated sample return missions.Next, I report the discovery of a method that distinguishesbetween primary and distant secondary craters in high resolutionplanetary images. For a given crater size, the largest bouldersof secondary craters are significantly larger than those ofprimary craters. The ability to identify distant secondarycraters will help constrain primary production rates of smallcraters and improve surface age determination of small areasbased on small crater counts.Third, I characterize the distributions of boulders ejected from18 lunar impact craters. I find that in large craters, thelargest boulders are preferentially ejected at low velocities(closer to the crater), whereas the largest boulders from smallcraters are ejected over a wider range of ejection velocities. Also, for a given crater size, deeper regolith reduces themaximum ejection velocity attained by a boulder ejected from acrater. I show that this is a logical result of the streamlinesof excavation in an impact when there are no coherent boulders inthe regolith. Cumulative plots of the boulders have slopessteeper than -2, as do secondary craters. This result isexpected because ejecta fragments produce secondary craters.Finally, I describe the morphology of some lunar crater walllandslides that strongly resemble martian gullies, despite thelack of geologically active water on the Moon today or in thepast. The lunar features indicate that alcove-channel-apronmorphology, attributed on Mars to seepage of liquid water, canalso form via a dry landslide mechanism. Therefore alcove-channel-apron morphology is not diagnostic of water carvedgullies.

Page generated in 0.0473 seconds