Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.571709
Title: Manipulation of nanoparticles by pushing operations using an Atomic Force Microscope (AFM)
Author: González Romo, Mario Javier
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2012
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Abstract:
This thesis presents new paradigms for a particular class of non-prehensile manipulators of nanoscale objects that are limited to modelling accurately the relative motion of objects using continuous mechanics where the contact area is not presented. This restrictions results in models which have low accuracy and a lack of understanding about the real motion of the nanoscale object. The newly developed paradigms are focused on three topics: characterisation and analysis of forces present during motion at nanoscale in two dimensional space; characterisation and analysis of the quasi-static motion of nanoscale objects using the the instantaneous centre of rotation iCOR; and characterisation and analysis of the quasi-static,impulsive and dynamic motion of nanoscale objects using motion constraints and the iCOR. For characterisation and analysis of forces present on objects being manipulated at nanoscale, new models to characterise rolling and sliding motion are introduced. For the sliding case a relation between friction load (force and torque) and slip motion (displacement and rotation) for rigid nano-object sliding on a flat and a rough surface, where the distribution of the normal contact forces is assumed to be known a priori and the friction is assumed to be independent of slip rate is introduced. Every point of frictional contact is assumed to obey Coulomb’s friction law. A developed set of equations are solved, performing high accuracy integration techniques such as the Bulirsch-Stoer Method implemented on a computing programming language such as FORTRAN. The full relation between the frictional load and the slip motion for a nano-object can thus be described by its iCOR. A new methodology to model the quasi-static motion of nanoscale objects is presented from which are derived equations that can be used to approximate the trii bological parameters of the nano-objects being manipulated for known and unknown contact pressure distributions. The characterisation of the tribological parameters, such as the coefficient of friction μ, is obtained from generated maps using the applied force or the observed iCOR location of the nano-object being manipulated. The approach has several advantages, including simplicity, robustness, and an ability to simulate classes of systems that are difficult to simulate using spatial mechanics. The final part of this thesis introduces a novel constraint-based method in combination with a minimum force principle to locate the iCOR position for nano-objects at quasi-static motion. Furthermore, the iCOR location for impulsive and dynamic motion cases are introduced. The results generated by modelling these cases can describe the full motion of the manipulated nano-object and generate knowledge of their tribological parameters.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.571709  DOI: Not available
Keywords: TJ Mechanical engineering and machinery
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