Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 108 for “"hopper"”.
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Sodium Fluoride Hopper Crystals
Dental caries is still prevalent despite the current understanding and use of fluoride. Faster dissolving crystals of NaF in a dentifrice could improve the efficacy of current preventative treatments. In this study, crystals of sodium fluoride with a high surface area to volume ratio were prepared …
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Spacecraft Systems Design for LuNaDrone: A Deployable Lunar Hopper
L'abstract è presente nell'allegato / the abstract is in the attachment
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Development of a cold gas propulsion system for the TALARIS hopper
… Artificial Lunar And Reduced gravIty Simulator) hopper is a small prototype flying vehicle developed as an Earth-based testbed for guidance, navigation, and control algorithms that will be used for robotic exploration of lunar and other planetary surfaces. It has two propulsion systems: (1) a …
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Development of modular real-time software for the TALARIS lunar hopper testbed
Hoppers have recently emerged as a viable means for planetary exploration, and as with any new vehicle, significant testing is required to validate guidance, navigation, and control (GNC) algorithms. Furthermore, the structure, organization, and timing of the real-time software must be planned …
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Automatic design of the gravity-reducing propulsion system of the TALARIS Hopper Testbed
… design solutions with that of the MIT TALARIS Hopper Testbed. Earth-based reduced-gravity simulators are platforms that allow hosted vehicles to experience a dynamic environment -from a guidance, navigation, and control perspective- analog to other planetary surfaces. Simulators are used for …
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Unique abilities of hopper spacecraft to enable national objectives for solar system exploration
… conventional and other conceived approaches, hopper spacecraft offer unique advantages in exploring Solar System objects beyond Earth. The present work began with a survey - based on documents from the White House, Congress, NASA, and the international planetary science community - of …
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An analysis of buckling in spherical shells and its design implications for hopper poppers
… was to investigate a key design parameter of a hopper popper: the force it takes to "load," or invert, the popper. A hopper popper is an injection-molded rubber toy in the shape of a hemispherical shell that stores elastic potential energy when inverted. There is new interest for hopper poppers …
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A finite element analysis and redesign of the draftsill casting on a railroad hopper car
… element analysis and redesign of a railroad hopper car draftsill. The purpose of the work was to modify the current draftsill structure to minimize its weight without compromising its current capabilities and foundry production specifications. The intuitive optimization procedure used both …
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Design and development of a frequency hopper based on the DECT system for the 902-928 MHz ISM band
… band. A theoretical design of a slow frequency hopper (SFH) based on an existing DECT RF front end and a custom-designed system controller was developed. An innovative FH synchronization technique that eliminates the need for a separate FH tracking loop and can be implemented completely at …
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Evaluation study for an ammonia-fed and solid-oxide fuel cell powered trailing suction hopper dredger for Van Oord Offshore Contractors
… possibility of a Zero-Emission Trailing Suction Hopper Dredger. For this evaluation study the possibility towards an Ammonia-fed and Solid-Oxide-Fuel-Cell powered hybrid Trailing Suction Hopper Dredger (TSHD) has been researched. This has been done through the analysis of the Power Demand …
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A Reconsideration of the Interpretation and Analysis Typically Applied to Edward Hopper’s Art During the 1940s
… the consideration and appreciation of Edward Hopper’s art focusing on the 1940s. The thesis proposes that Hopper should be categorised as a Modernist. This notion was explored by selecting and critically evaluating literature and original paintings by Hopper. The literature utilised for this …
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Design and development of a multi-shot foam projectile toy
… of the initial work was the development of Hopper Popper ActivationTM, which uses a bistable rubber spring to fire Nerf foam balls. Due to its novel nature and the simplicity of its design, Hopper Popper Activation has since been integrated into a single projectile toy named the Atom …
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Experimental and numerical study of flow characteristics and segregation in flow enhanced systems
… particles and powders are placed in a test hopper. A mesh is placed at the bottom of the hopper to hold the magnetic particles while the powder is discharged through the mesh. It is shown that this method may be used for controlled discharge of cohesive powders and hence may be used also for …
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Mission design for safe traverse of planetary hoppers
Planetary hoppers are a new class of vehicle being developed that will provide planetary surface mobility by reusing the landing platform and its actuators to propulsively ascend, translate, and descend to new landing points on the surface of a planetary body. Hoppers enhance regional exploration, …
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Modeling and vehicle performance analysis of Earth and lunar hoppers
Planetary hoppers-vehicles which travel over the surface as opposed to on it-offer significant advantages over existing rovers. Above all, they are able to travel quickly and can overcome terrain obstacles such as boulders and craters. The Next Giant Leap team in the Google Lunar X- PRIZE …
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Toward building practical privacy enhancing technologies.
… Major: Computer science. Advisor:Prof. Nicholas Hopper. 1 computer file (PDF); ix, 107 pages.
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The geochemistry of the Olivine Melilitetes and related rocks of Namaqualand Bushmanland, South Africa
… the same rock; (b) euhedral and often skeletal (hopper) olivines that are richer in Mg and Ni than HILN olivines in the same rock. Some of the euhedral olivines show abnormal zonation patterns ("unusual" hoppers). Hopper and HILN olivines contain fluid and carbonate inclusions which apparently …
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Use and sizing of rocket hoppers for planetary surface exploration
The utilization of rocket hoppers can provide a valuable means of obtaining enhanced mobility for planetary surface exploration missions. Hoppers offer higher exploration versatility than landers, rovers, or other surface exploration systems through their ability to quickly traverse difficult …
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Order and Asymmetry in Jammed Systems
… flow, we simulated 2D granular flow in a hopper. A hopper is a container with an opening at the bottom. Simulated disks are placed in the hopper with the bottom closed and then released. We developed a new tangential force model to simulate hopper flow, that matches experiments and shows …
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Pressurized Metal Bellows Shock Absorber for Space Applications.
… In contrast to rovers and stationary landers, hoppers explore by making multiple launch and landing hops. They have the advantage of being able to avoid terrain that would cause a rover to become stuck. A hopper may require a landing shock absorber that can reliably operate multiple times in …
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