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 43 for “"ratchet"”.
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Ratchet models of molecular motors
Transportvorgänge in und von Zellen sind von herausragender Bedeutung für das Überleben des Organismus. Muskeln müssen sich kontrahieren können, Chromosomen während der Mitose an entgegengesetzte Enden der Zelle bewegt und Organellen, das sind von Membranen umschlossene Kompartimente, entlang …
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Leidenfrost Drop Ratchet Impact Dynamics
… the behavior of droplets impacting a micro scale ratchet structure. In particular, we theorize that surface roughness can lead to an inconsistent vapor layer, allowing for propulsion resulting from contact boiling. Additionally, pressure differences in the vapor layer can drive a convective vapor …
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Ratchet dynamics in nonlinear Klein-Gordon systems
… have presented and studied a novel design for a ratchet potential for soliton excitations. The investigation was focused on the ratchet dynamics of nonlinear Klein-Gordon kinks in a periodic and asymmetric lattice of point-like inhomogeneities in the overdamped regime. In addition, we explained …
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Two Examples of Ratchet Processes in Microfluidics
The ratchet effect can be exploited in many types of research, yet few researchers pay attention to it. In this thesis, I investigate two examples of such effects in microfluidic devices, under the guidance of computational simulations. The first chapter provides a brief introduction to ratchet …
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Localization, escape rate and delocalization in kinked ratchet potentials
The particle localization in ratchet potentials with segments of reverse directions, or kinked ratchets, is computationally studied. Kinks localize a particle on on-off pulsating ratchet potentials, forming stable points in the effective potential. Analogous Kramers rate for transition between …
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An Investigation of Compliant Over-running Ratchet and Pawl Clutches
… theory can be used to design over-running ratchet and pawl clutches with reduced part count, lower assembly and manufacturing time while maintaining functionality. An extension of the theory to the micro regime is also briefly addressed. The results of the research show that the ratchet and …
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Development of track-walking DNA nanomotors
… mechanisms and driving methods, including ratchet and burn-the-bridge for the former and fuels, enzymes, light for the latter. These nanowalkers have been applied to nanoscale molecular transportation, chemical synthesis and more. However, the design principles of these artificial …
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Avlastningsyta till bussresenärer för att öka arbetsmöjligheterna med laptop
… are linked through hinges, it forms a frame. Ratchet straps are attached across the frame. The component offers an adjustable surface area. When the component is maximally extended the ratchet straps are stretched out and form a flat surface to enable placement of smaller articles. When the …
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Directed transport without net bias in physics and biology
Ratchets allow for directed transport without net bias. In this context, 'no net bias' means that net potential gradients on the system or non-zero initial velocities are not necessary to achieve a long-term non-zero average velocity. One type of a ratchet is the rocking ratchet, where a particle …
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Directed transport without net bias in physics and biology
Ratchets allow for directed transport without net bias. In this context, 'no net bias' means that net potential gradients on the system or non-zero initial velocities are not necessary to achieve a long-term non-zero average velocity. One type of a ratchet is the rocking ratchet, where a particle …
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Simulation studies of Brownian motors
… motors, the feedback-controlled flashing ratchet and an artificial molecular motor concept, the results of which not only drive experimental considerations but also illuminate physical behaviors that may be applicable to other Brownian motors. A flashing ratchet rectifies the motion of …
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Factors which can affect the preferences of the elderly for hand pruners
… with compound lever, and anvil and blade with ratchet mechanism. Other characteristics included handle design and weight. The Friedman ranking test was used to determine the factors which significantly affected pruner preferences. Of the variables measured, sex, hand size, grip strength, and …
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Peak Mitotic Cyclin Permits Mitotic Exit
… oscillation of cyclin/Cdk activity, suggested 'ratchet' models to explain cell cycle ordering. If the Cdk activating threshold for the first event is greater than the inhibitory threshold for the second, then these thresholds form an activity ratchet that couples the sequence to Cdk oscillation. …
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ACTIVE HIP ACTUATION FOR WALKING BIPED WITH PASSIVE OPTION
… Parallel Ankle Actuator (HPAA) and the Hip Ratchet System (HRS). This study focused on the design and testing of the HRS which achieves hip actuation through the use of a locking mechanism integrated into each hip joint that couples the legs to a shared drive system. The ability to lock and …
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RattleSnake : stochastic folding for chain programmable matter
… arbitrary paths in configuration space and 2) ratchets that are programmed ahead of time and are entirely passive. We developed a chain using the ratchet concept and also constructed a new active, electromechanical chain with reduced cost and improved speed and torque compared to previous …
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Molekulargenetische und zytogenetische Untersuchungen zur paternalen Introgression beim gynogenetischen Amazonenkärpfling, Poecilia formosa
… im Laufe der Generationen anhäufen ("Muller’s ratchet"), und schnelle Anpassung an eine veränderte Umwelt oder neue Abwehrstrategien gegen Parasiten werden erschwert. Der Amazonenkärpfling, Poecilia formosa, stellt einen Organismus dar, dessen Fortpflanzung in Folge eines interspezifischen …
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Development of office paper attachment methodologies
… The concept that was developed and pursued was a ratcheting clip. The ratchet allowed the clip to be tightened, but prevented it from being loosened, unless a release button was pressed. The prototype was built and tested, and the results proved that the ratcheting concept has the potential to …
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PROTON BEAM WRITING OF MICRO/NANO FLUIDIC DEVICES FOR DNA ANALYSIS AND PARTICLE SEPARATION
… confinement and particle separation using a ratchet structure. PBW is a direct write technique can be focused down to sub 30 nm size. Proton beam can penetrate a photoresist very deep with minimal proximity effects allow us to fabricate 3D high aspect ratio molds.
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Exploration of versatile clamping mechanism and brace system for table attachment to lamp posts and poles in urban settings
… inappropriate clamping mechanisms. In choosing a ratchet tie down strap as the final clamping mechanism, further improvements and designs were explored. Ultimately, an all in one table and brace system, involving an unfolding table surface was settled on.
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