The restrictions of micro-scale systems are approaching rapidly. In anticipation of this development, nano-scale electronics has become the focus of many researchers and engineers in academia and industry since early 1990s. The basic building blocks of modern integrated circuits have been diodes and transistors with their current-voltage I-V characteristics being of prime significance for the design of complex signal processing and shaping devices and systems. Classical and semi-classical physical principles are no longer powerful enough or even valid to describe the phenomena involved. The application of rich and powerful concepts in quantum theory has become indispensable. These facts have been influential in undertaking this research project. This research is built upon the determination of the Eigenpairs of one and two dimensional positive differential operators with periodic boundary conditions. The Schrödinger equation was solved for positive operators in both one and two dimensions. Fourier series were used to express the derivatives as the summation of Fourier terms. This led to a novel approach for the calculation of the eigenmodels of a perturbed potential well. The perturbation can be done via an electric field applied to the potential well. The research in this thesis includes a thorough understanding of quantum mechanics fundamentals, mastering of different approximation techniques such as the variational technique and results that have been generated and published using the novel techniques.

Finite element models are used frequently in both engineering and scientific research. While they can provide useful information as to the performance of materials, as length scales are decreased more sophisticated model descriptions are required. It is also important to develop methods by which existing models may be verified against experimental findings. The present study evaluates the ability of various finite element models to predict materials behaviour at length scales ranging from several microns to tens of nanometers. Considering this motivation, this thesis is provided in manuscript form with the bulk of material coming from two case studies. Following an overview of relevant literature in Chapter 2, Chapter 3 considers the nucleation of delta-zirconium hydrides in a Zircaloy-2 matrix. Zirconium hydrides are an important topic in the nuclear industry as they form a brittle phase which leads to delayed hydride cracking during reactor start-up and shut-down. Several FE models are used to compare present results with literature findings and illustrate the weaknesses of standard FE approaches. It is shown that standard continuum techniques do not sufficiently capture the interfacial effects of an inclusion-matrix system. By using nano-scale material descriptions, nucleation lattice strains are obtained which are in good agreement with previous experimental studies. The motivation for Chapter 4 stems from a recognized need to develop a method for modeling corrosion behaviour of materials. Corrosion is also an issue for reactor design and an ability to predict failure points is needed. Finite element models could be used for this purpose, provided model accuracy is verified first. In Chapter 4 a technique is developed which facilitates the extraction of sub-micron resolution strain data from correlation images obtained during in-situ tensile deformation. By comparing image correlation results with a crystal plasticity finite element code it is found that good agreement between the two exists. The method outlined is material independent and could be applied to most metallurgical studies. Chapter 5 reviews the findings of each case study and makes suggestions as to the direction of future research. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2013-09-30 16:05:52.934

Strain detecting with carbon nanotube (CNT) networks is one of the encouraging findings in sensor technologies. Two types of CNT based films are available for strain detection, namely CNT composite films and CNT films. Configurations of the CNT networks in these films can be made into random and aligned distributions. Understanding of fundamental knowledge regarding piezoresistive response in CNT networks in particular of the CNT film is not quite available, and this is the motivation of the present thesis. In this thesis, piezoresistive response of CNT networks under in-plane straining was studies in details first. Based on the stick percolation model, the relation between the density and conductance in CNT networks (with randomly distributed) was established and then the models which describe the relation between the density and piezoresistive sensitivity and the relation between density and piezoresistive linearity, respectively, were developed. After that, fabrication of CNT networks with aligned distributions was studied. Likewise, the models as developed for CNT network with random distributions were developed for ones with aligned distributions. Finally, modeling of the stress transfer between the nanotubes and polymer matrix was studied. This study has led to the following conclusions: (1) piezoresistive response in CNT networks of the CNT film follows the stick percolation model with the critical exponent coefficient (α) in the model being 1.938; (2) it is feasible to fabricate aligned CNT networks of varying densities with the technique which combines the spray deposition and externally applied magnetic field; (3) the configuration of CNT networks, in addition to their density, was a primary factor governing their piezoresistive response; (4) slipping occurs at the interface between the nanotube and polymer matrix when the films are subject to in-plane straining. The contributions of this study are: (1) the knowledge along with a percolation model for piezoresistive response of CNT networks of the CNT film, (2) a fabrication technique to align CNT networks of the CNT film, and (3) the knowledge along with a model for interaction between the CNT and polymer substrate in the CNT film.

A variety of open and closed multi-layered nanoparticle structures have been considered analytically and numerically for their use as scatterers and radiators. These include metamaterial-inspired structures based on dielectrics and metals excited by either plane waves or electric Hertzian dipoles at optical frequencies. Both passive and active (gain impregnated dielectric) materials have been considered. Enhanced and mitigated scattering and radiating effects have been modeled. Nano-antenna and nano-amplifier configurations for optical applications have been emphasized. A review of these modeling efforts will be presented.

Nano-scale fluid flow is unlike transport on the macro-scale. Pressure gradients typically dominate effects on a large scale while thermal gradients contribute negligibly to the motion of fluid. The situation entirely reverses on the nano-scale. At a microscopic level, flows induced by thermal gradients are caused by forces that act on atoms or molecules near an interface. These thermo-osmotic forces cannot, at present, be derived analytically or measured experimentally. Clearly, it would be useful to calculate these forces via molecular simulations, but direct approaches fail because in the steady-state, the average force per particle vanishes, as the thermo-osmotic force is balanced by a gradient in shear stress. In our journey to indirectly calculate the osmotic force, we met another unknown in the field of molecular theory at interfaces: the microscopic pressure tensor. The latter is an open problem since the microscopic pressure near an interface is not uniquely defined. Using local thermodynamics theories, we relate the thermo-osmotic force to the gradient of the microscopic pressure tensor. Yet, because the pressure is not uniquely defined, we arrive at multiple answers for the thermo-osmotic force, where at most one can be correct. To resolve the latter puzzle, we develop a direct, non-equilibrium simulation protocol to measure the thermo-osmotic force, whereby a thermal gradient is imposed and the osmotic force is measured by eliminating the shear force. Surprisingly, we find that the osmotic force cannot be derived from the gradient of well-known microscopic pressure expressions. We, therefore, derive a thermodynamic expression that gets close. In this work, we report the first, direct calculation of the thermo-osmotic force while simultaneously showing that standard microscopic pressure expressions fail to predict pressure gradients.

The purpose of this work was to investigate the use of nanoscale Fe3O4 as a catalytst for destruction of trichloroethylene (TCE) and 1,2-dichloroethane (1,2-DCA) by persulfate in spiked water and soil. First, nanoscale Fe3O4 was prepared by chemical coprecipitation. X-ray powder diffraction (XRD) was used to confirm the crystal structure; And size identification was performed using the scanning electron microscopy (SEM). The effectiveness of using 3 wt% soluble starch (SS) to stabilize nanoscale Fe3O4 was also studied. It was found that SS could effectively disperse the nanoparticles for more than one month. Therefore, SS was chosen to prepare the nanoscale Fe3O4 slurry. The efficiency of nanoscale Fe3O4 as an activator for persulfate remediation of TCE and 1,2-DCA in aqueous solutions (DI water, simulated groundwater, and actual groundwater) was then investigated. The results showed that all test removal efficiency of TCE and 1,2-DCA was more than 95%. Use of the persulfate for destruction of TCE and 1,2-DCA produced some by-products. The primary reaction products were cis-1,2-Dichloroethylene (cis-1,2-DCE) and trans-1,2-Dichloroethylene (trans-1,2-DCE)¡F The secondary daughter prodnct was vinyl chloride (VC). The VC produced is gradually degraded to safer substances (ethene, ethane, and methane). The nanoscale Fe3O4 slurry and the persulfate injection coupled with the electrokinetic (EK) process was tested for remediation of TCE and 1,2-DCA in saturated soil. The results showed that injection of persulfate into the EK reservoir could decrease the electrode polarization, and increase the electroosmotic flow and current density. When persulfate was injected into the cathode reservoir, the derived sulfate radicals would transfer into the soil compartment by ion migration. The injection of persulfate into the cathode reservoir was more efficient than injection of persulfate into the anode reservoir. The removal efficiency for TCE and 1,2-DCA was more than 96% in all tests. The remediation system was assessed for potential application in-situ. Soil was spiked with high TCE and 1,2-DCA and aged for a week. The injection of persulfate and nanoscale Fe3O4 slurry coupled with the EK process was tested for remediation of the aged contaminated soil. The results showed that the target contaminants (TCE and 1,2-DCA) met the Taiwan¡¦s EPA¡¦s control standard. After 30 d of remediation, the by-products (cis-1,2-DCE, trans-1,2-DCE, and VC) had also been removed to below the action limit. A cost analysis was performed in order to demonstrate the economic feasibility of the remediation method in this study. Operating costs (chemicals + electricity bill) of all tests were assessed. The results showed that the costs were 8000-17000 NT$/m3, which is economically reasonable.

Recently, the use of thermite-based pressure waves for applications in cellular transfection and drug delivery have shown significant improvements over previous technologies. In the present study, a new technique for producing thermite-generated pressure pulses using fully-dense nano-scale thermite mixtures was evaluated. This was accomplished by evaluation of a stoichiometric mixture of aluminium (Al) and copper(II)-oxide (CuO) prepared by mechanical alloying. Flame propagation speeds, constant-volume pressure characteristics and underwater pressure characteristics of both a micron-scale and mechanically alloyed mixture were measured experimentally and compared with conventional nano-scale thermites. It was determined that mechanically alloyed mixtures are capable of attaining flame propagation speeds on the same order as nano-scale mixtures, with flame speeds reaching as high as approximately 100 m/s. Constant-volume pressure experiments indicated that mechanically alloyed mixtures result in lower pressurization rates compared with conventional nano-scale mixtures, however, an improvement by as much as an order of magnitude was achieved compared with micron-scale mixtures. Thermochemical equilibrium predictions for pressures observed in constant-volume reactions were found to capture relatively well the equilibrium pressure for both low and high values of relative density. Generally, the predictions over-estimated the measured pressures by approximately 60%. Results from underwater experiments indicated that the mechanically alloyed samples produced peak shock pressures and waveforms similar to those for a nano-scale Al-Bi2O3 mixture reported by Apperson et al. (2008). In an effort to model the pressure signal obtained from the underwater reaction, calculations were performed based on the rate of expansion of the high pressure gas sphere. Predicted pressures were found to agree fairly well in terms of both the peak pressure and pressurization rate. The present study has thus identified the ability for mechanically alloyed thermite mixtures to produce underwater pressure profiles that may be conducive for applications in cellular transfection and drug delivery. Récemment, l'utilisation d'ondes de pression produite par des mélanges de thermite pour des applications dans la transfection cellulaire et l'administration de médicaments ont démontré des améliorations importantes par rapport aux technologies précédentes. Dans l'étude ci jointe, une nouvelle technique pour produire des impulsions de pression générée par un mélange thermite, soumit a de l'alliage mécanique, a été évaluée. Ceci a été accompli par l'évaluation d'un mélange stoechiométrique d' aluminium (Al) et de l'oxyde de cuivre(II) (CuO), préparé par mécanosynthèse. Les vitesses de propagation de la flamme, les caractéristiques de pression pour la combustion à volume constant et les caractéristiques de pression pour la combustion sous l'eau ont été mesurées expérimentalement et comparés avec les thermites conventionnel à l'échelle nano. Nous avons déterminé que les mélanges alliés mécaniquement sont capables d'atteindre des vitesses de propagation de flamme du même ordre que les mélanges à l'échelle nanométrique, atteignant jusqu'à environ 100 m/s. Les expériences de combusition à volume constant, indique que les mélanges alliés mécaniquement induit des taux de pressurisation inférieures à celles des mélanges de nano-échelle conventionnel, cependant, une amélioration de près d'un ordre de grandeur a été atteint par rapport aux mélanges d'échelle micronique. Prédictions thermochimiques des pression de compbustion se sont révélés capable de relativement bien saisir les valeurs observées dans les expériences à volume constant. En règle générale, les prévisions sur-estimé les pressions mesurées par environ 60%. Les résultats des expériences sous-marines ont indiqué que les échantillons alliés mécaniquement ont produit des pressions et des profils d'onde similaires à celles produit par un mélange de Al-Bi2O3 de nano-échelle, comme indiqué par Apperson et al. (2008). Pour modéliser les pressions obtenues dans les expériences sous-marines, des calculs basés sur le taux d'expansion de la bulle de gaz à haute pression ont été obtenus. Les pressions prédites ont été trouvés d'être relativement en accord avec la pression maximale et le taux de pressurisation observé. Cette étude a ainsi identifié la possibilité pour l'utilisation des mélanges de thermites alliés mécaniquement pour produire des profils de pression sous l'eau propices pour des applications de transfection cellulaire et l'administration de médicaments.

Recently, the use of thermite-based pressure waves for applications in cellular transfection and drug delivery have shown significant improvements over previous technologies. In the present study, a new technique for producing thermite-generated pressure pulses using fully-dense nano-scale thermite mixtures was evaluated. This was accomplished by evaluation of a stoichiometric mixture of aluminium (Al) and copper(II)-oxide (CuO) prepared by mechanical alloying. Flame propagation speeds, constant-volume pressure characteristics and underwater pressure characteristics of both a micron-scale and mechanically alloyed mixture were measured experimentally and compared with conventional nano-scale thermites. It was determined that mechanically alloyed mixtures are capable of attaining flame propagation speeds on the same order as nano-scale mixtures, with flame speeds reaching as high as approximately 100 m/s. Constant-volume pressure experiments indicated that mechanically alloyed mixtures result in lower pressurization rates compared with conventional nano-scale mixtures, however, an improvement by as much as an order of magnitude was achieved compared with micron-scale mixtures. Thermochemical equilibrium predictions for pressures observed in constant-volume reactions were found to capture relatively well the equilibrium pressure for both low and high values of relative density. Generally, the predictions over-estimated the measured pressures by approximately 60%. Results from underwater experiments indicated that the mechanically alloyed samples produced peak shock pressures and waveforms similar to those for a nano-scale Al-Bi2O3 mixture reported by Apperson et al. (2008). In an effort to model the pressure signal obtained from the underwater reaction, calculations were performed based on the rate of expansion of the high pressure gas sphere. Predicted pressures were found to agree fairly well in terms of both the peak pressure and pressurization rate. The present study has thus identified the ability for mechanically alloyed thermite mixtures to produce underwater pressure profiles that may be conducive for applications in cellular transfection and drug delivery. Récemment, l'utilisation d'ondes de pression produite par des mélanges de thermite pour des applications dans la transfection cellulaire et l'administration de médicaments ont démontré des améliorations importantes par rapport aux technologies précédentes. Dans l'étude ci jointe, une nouvelle technique pour produire des impulsions de pression générée par un mélange thermite, soumit a de l'alliage mécanique, a été évaluée. Ceci a été accompli par l'évaluation d'un mélange stoechiométrique d' aluminium (Al) et de l'oxyde de cuivre(II) (CuO), préparé par mécanosynthèse. Les vitesses de propagation de la flamme, les caractéristiques de pression pour la combustion à volume constant et les caractéristiques de pression pour la combustion sous l'eau ont été mesurées expérimentalement et comparés avec les thermites conventionnel à l'échelle nano. Nous avons déterminé que les mélanges alliés mécaniquement sont capables d'atteindre des vitesses de propagation de flamme du même ordre que les mélanges à l'échelle nanométrique, atteignant jusqu'à environ 100 m/s. Les expériences de combusition à volume constant, indique que les mélanges alliés mécaniquement induit des taux de pressurisation inférieures à celles des mélanges de nano-échelle conventionnel, cependant, une amélioration de près d'un ordre de grandeur a été atteint par rapport aux mélanges d'échelle micronique. Prédictions thermochimiques des pression de compbustion se sont révélés capable de relativement bien saisir les valeurs observées dans les expériences à volume constant. En règle générale, les prévisions sur-estimé les pressions mesurées par environ 60%. Les résultats des expériences sous-marines ont indiqué que les échantillons alliés mécaniquement ont produit des pressions et des profils d'onde similaires à celles produit par un mélange de Al-Bi2O3 de nano-échelle, comme indiqué par Apperson et al. (2008). Pour modéliser les pressions obtenues dans les expériences sous-marines, des calculs basés sur le taux d'expansion de la bulle de gaz à haute pression ont été obtenus. Les pressions prédites ont été trouvés d'être relativement en accord avec la pression maximale et le taux de pressurisation observé. Cette étude a ainsi identifié la possibilité pour l'utilisation des mélanges de thermites alliés mécaniquement pour produire des profils de pression sous l'eau propices pour des applications de transfection cellulaire et l'administration de médicaments.

Nano-manufacturing is receiving significant attention in industry due to the ever-growing interest in nanotechnology in research institutions. It is hypothesized that single-step or direct-write nano-scale machining might be achieved by coupling nano-probe field emission with radiation transfer. A laser may be used to heat a workpiece within a microscopic region that encloses an even smaller nanoscopic region subjected to a focused electron beam. The electron-beam supplies marginal heat sufficient to remove a minute volume of material by evaporation or sublimation. Experimentally investigating this hypothesis requires an estimate of the power needed in the electron-beam. To this end, a detailed numerical study is conducted to study the possibility of using the nano-probe field emission for nano-machining. The modeling effort in this case is divided into two parts. The first part deals with the electron-beam propagation inside a target workpiece. The second part considers the temperature increase due to the energy transfer between the electron-beam and the workpiece itself. A Monte Carlo/Ray Tracing technique is used in modeling the electron-beam propagation. This approach is identical to that of a typical Monte Carlo simulation in radiative transfer, except that proper electron scattering properties are employed. The temperature distribution inside a gold film is predicted using the heat conduction equations. Details of the various numerical models employed in the simulation and a series of representative results will be presented in this dissertation.

Molecular transport through hollow cores of crystalline carbon nanotubes (CNTs) are of considerable interest from the fundamental and application point of view. This dissertation focuses on understanding molecular transport through a membrane platform consisting of open ended CNTs with ~ 7 nm core diameter and ~ 1010 CNTs/cm2 encapsulated in an inert polymer matrix. While ionic diffusion through the membrane is close to bulk diffusion expectations, gases and liquids were respectively observed to be transported ~ 10 times faster than Knudsen diffusion and ~ 10000-100000 times faster than hydrodynamic flow predictions. This phenomenon has been attributed to the non-interactive and frictionless graphitic interface. Functionalization of the CNT tips was observed to change selectivity and flux through the CNT membranes with analogy to gate-keeper functionality in biological membranes. An electro-chemical diazonium grafting chemistry was utilized for enhancing the functional density on the CNT membranes. A strategy to confine the reactions at the CNT tips by a fast flowing liquid column was also designed. Characterization using electrochemical impedance spectroscopy and dye assay indicated ~ 5-6 times increase in functional density. Electrochemical impedance spectroscopy experiments on CNT membrane/electrode functionalized with charged macro-molecules showed voltage-controlled conformational change. Similar chemistry has been applied for realizing voltage-gated transport channels with potential application in trans-dermal drug delivery. Electrically-facilitated transport ( a geometry in which an electric field gradient acts across the membrane) through the CNT and functionalized CNT membranes was observed to be electrosmotically controlled. Finally, a simulation framework based on continuum electrostatics and finite elements has been developed to further the understanding of transport through the CNT membranes.