subject:(Core dynamics)

University of Manchester

1. Sargant, Robert John. Molecular dynamics simulations of elongated molecules.

Degree: PhD, 2012, University of Manchester

URL: https://www.research.manchester.ac.uk/portal/en/theses/molecular-dynamics-simulations-of-elongated-molecules(35c31c02-aa1f-4c87-bab9-db81d813974b).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566525

► The existence of a thermotropic biaxial nematic liquid crystal phase has been a topic of great interest for almost half a century. Of the various… (more)

▼ The existence of a thermotropic biaxial nematic liquid crystal phase has been a topic of great interest for almost half a century. Of the various mesogenic shapes suggested as being able to form this phase, theory has suggested that the V-shaped or "bent-core" molecule is one of the most promising candidates. In this thesis we use a simple mesogenic model of a bent-core molecule, constructed from a number of repulsive Weeks-Chandler-Andersen potentials that are assembled into a rigid V shape. Using this model we explore the spontaneous phase behaviour that occurs in a wide array of different systems of mesogens, using molecular dynamics simulations and isotropic initial conditions. We study the relationship between molecular bend angle and phase behavior for molecules constructed from 11 potentials. We find that the phase behaviour splits into two regions, above and below a critical bend angle. Molecules wider than this angle exhibit isotropic, uniaxial nematic and smectic A phases. Narrower molecules show no uniaxially aligned phases, and instead have a clustered phase with short-range ordering and no global alignment director. Increasing system size improves the smectic layering in the wider molecules, but does not affect the global alignment of the narrower molecules. Our model is extended to include the effect of the arm length of the molecule by changing the number of potentials from which the mesogens are constructed. As the molecule is reduced in size, the critical bend angle is seen to move slowly towards more linear molecules, reducing the size of the parameter space in which uniaxial nematic alignment is possible. At 5 beads, all mesophases are seen to disappear and systems remain isotropic. We also study the behaviour of binary mixtures of bent-core molecules, both of differing arm lengths and of differing bend angles. For arm length mixtures, molecules are seen to remain mixed in the isotropic and nematic phases, and phase separate on transition to a smectic phase. In addition, uniaxial nematic phases are induced in systems that have no nematic phase of their own in isolation. For mixtures of different bend angles, systems remain fully mixed in the smectic phases for differences of up to 10 degrees, and beyond this the two components begin to separate at the nematic–smectic transition.

Subjects/Keywords: 541; liquid crystals; bent-core; molecular dynamics

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APA (6^th Edition):

Sargant, R. J. (2012). Molecular dynamics simulations of elongated molecules. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/molecular-dynamics-simulations-of-elongated-molecules(35c31c02-aa1f-4c87-bab9-db81d813974b).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566525

Chicago Manual of Style (16^th Edition):

Sargant, Robert John. “Molecular dynamics simulations of elongated molecules.” 2012. Doctoral Dissertation, University of Manchester. Accessed January 27, 2021. https://www.research.manchester.ac.uk/portal/en/theses/molecular-dynamics-simulations-of-elongated-molecules(35c31c02-aa1f-4c87-bab9-db81d813974b).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566525.

MLA Handbook (7^th Edition):

Sargant, Robert John. “Molecular dynamics simulations of elongated molecules.” 2012. Web. 27 Jan 2021.

Vancouver:

Sargant RJ. Molecular dynamics simulations of elongated molecules. [Internet] [Doctoral dissertation]. University of Manchester; 2012. [cited 2021 Jan 27]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/molecular-dynamics-simulations-of-elongated-molecules(35c31c02-aa1f-4c87-bab9-db81d813974b).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566525.

Council of Science Editors:

Sargant RJ. Molecular dynamics simulations of elongated molecules. [Doctoral Dissertation]. University of Manchester; 2012. Available from: https://www.research.manchester.ac.uk/portal/en/theses/molecular-dynamics-simulations-of-elongated-molecules(35c31c02-aa1f-4c87-bab9-db81d813974b).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566525

UCLA

2. Cheng, Jonathan. Characterizing convection in geophysical dynamo systems.

Degree: Geophysics & Space Physics, 2015, UCLA

URL: http://www.escholarship.org/uc/item/69z5f5gz

► The Earth’s magnetic field is produced by a fluid dynamo in the molten iron outer core. This geodynamo is driven by fluid motions induced by… (more)

▼ The Earth’s magnetic field is produced by a fluid dynamo in the molten iron outer core. This geodynamo is driven by fluid motions induced by thermal and chemical convection and strongly influenced by rotational and magnetic field effects. While frequent observations are made of the morphology and time-dependent field behavior, flow dynamics in the core are all but inaccessible to direct measurement. Thus, forward models are essential for exploring the relationship between the geomagnetic field and its underlying fluid physics. The goal of my PhD is to further our understanding of the fluid physics driving the geodynamo.In order to do this, I have performed a suite of nonrotating and rotating convection laboratory experiments and developed a new experimental device that reaches more extreme values of the governing parameters than previously possible. In addition, I conduct a theoretical analysis of well-established results from a suite of dynamo simulations by Christensen and Aubert (2006). These studies are conducted at moderate values of the Ekman number (ratio between viscosity and Coriolis forces, ~ 10^−4), as opposed to the the extremely small Ekman numbers in planetary cores (~ 10^−15). At such moderate Ekman values, flows tend to take the form of large-scale, quasi-laminar axial columns. These columnar structures give the induced magnetic field a dipolar morphology, similar to what is seen on planets. However, I find that some results derived from these simulations are fully dependent on the fluid viscosity, and therefore are unlikely to reflect the fluid physics driving dynamo action in the core. My findings reinforce the need to understand the turbulent processes that arise as the governing parameters approach planetary values. Indeed, my rotating convection experiments show that, as the Ekman number is decreased beyond ranges currently accessible to dynamo simulations, the regime characterized by laminar columns is found to dwindle. We instead find a large variety of behavioral regimes ranging from axial columns to fully three-dimensional turbulence. By comparing these to direct numerical simulations and asymptotically-reduced models, we find broad agreement in both the heat transfer scaling properties and flow morphologies in these separate regimes. In particular, large, multi-scale axial vortices emerge consistently in numerical and asymptotic simulations. Such multi-scale structures in the core may be related to the Earth’s dipolar magnetic field structure. I have designed and fabricated a novel laboratory experimental device capable of characterizing these flow regimes in great detail using accurate heat transfer and velocity measurements and high-resolution flow imaging.

Subjects/Keywords: Geophysics; Core dynamics; Dynamo theory; Geophysical fluid dynamics; Rotating convection

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APA (6^th Edition):

Cheng, J. (2015). Characterizing convection in geophysical dynamo systems. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/69z5f5gz

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Cheng, Jonathan. “Characterizing convection in geophysical dynamo systems.” 2015. Thesis, UCLA. Accessed January 27, 2021. http://www.escholarship.org/uc/item/69z5f5gz.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Cheng, Jonathan. “Characterizing convection in geophysical dynamo systems.” 2015. Web. 27 Jan 2021.

Vancouver:

Cheng J. Characterizing convection in geophysical dynamo systems. [Internet] [Thesis]. UCLA; 2015. [cited 2021 Jan 27]. Available from: http://www.escholarship.org/uc/item/69z5f5gz.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Cheng J. Characterizing convection in geophysical dynamo systems. [Thesis]. UCLA; 2015. Available from: http://www.escholarship.org/uc/item/69z5f5gz

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. Lasbleis, Marine. Dynamique et évolution de la graine terrestre : Dynamics and evolution of the Earth’s inner core.

Degree: Docteur es, Sciences de la Terre, 2014, Lyon, École normale supérieure

URL: http://www.theses.fr/2014ENSL0962

►

Les progrès de l'imagerie sismique ces trente dernières années ont permis de révéler la structure complexe de la graine : une anisotropie cylindrique de quelques… (more)

▼

Les progrès de l'imagerie sismique ces trente dernières années ont permis de révéler la structure complexe de la graine : une anisotropie cylindrique de quelques pourcents dont la structure fine présente des variations radiales et latérales. Ce travail de thèse s’est concentré sur les différentes dynamiques susceptibles de provoquer une telle structure. [Il y a autre chose dans cette structure]Nous avons revisité la dynamique induite par la force de Lorentz, discutant les conditions aux limites, la croissance de la graine et la stratification en densité. La déformation n’est raisonnablement suffisante que pour des viscosités inférieures à 1012 Pa.s, dans la fourchette basse des estimations. Les modèles d'écoulements globaux dans la graine peuvent se classer en deux grandes catégories. Pour un profil de densité stable, seul un forçage extérieur, tel que la force de Lorentz, peut induire un écoulement. Dans le cas instable, la dynamique est contrôlée principalement par des instabilités de convection. Les nouvelles estimations de la diffusion thermique limitent les instabilités thermiques à des âges de graine de l'ordre de la centaine de millions d'années. En se focalisant sur deux paramètres, la viscosité et l'âge de la graine, nous avons construit un diagramme de régime qui compare quantitativement les différents modèles proposés dans la littérature. En croisant amplitude du taux de déformation et géométrie attendues, on peut raisonnablement restreindre les domaines qui pourraient engendrer la structure observée. Pourtant, aucun modèle n'est pour l'instant capable d'expliquer à la fois l'amplitude et la géométrie de l'anisotropie sismique et encore moins la dichotomie Est-Ouest. La couche F est une anomalie dans le noyau externe : d’une épaisseur de 200 km environ, à la base du noyau externe, elle présente des vitesses d’ondes sismiques plus faibles que celles prédites pour un noyau liquide parfaitement mélangé. Elle est interprétée comme une zone chimiquement appauvrie, en contradiction avec la cristallisation de la graine qui libère des éléments légers à la surface même de la graine. Nous étudions la possibilité d’une cristallisation en volume dans cette couche. Les particules de fer solides sédimentent en croissant dans un liquide de plus en plus appauvri en éléments légers. Cette neige de fer est stable sous certaines conditions, étudiées ici.

In the past thirty years, our understanding of the inner core structure has increased with the number of seismic studies. Observations reveal a global anisotropy with a cylindrical symmetry and radial and lateral heterogeneities. In this work, I have studied different hypothesis on the dynamics of the inner core to explain these observations. Revisiting the dynamics induced by the Lorentz force, we studied the effect of new boundary conditions, the effect of stratification and growth rate. However, the obtained flow is not strong enough to deform the media for viscosities larger than 1012 Pa.s, in the lower bound of the published inner core estimates. Deformation…

Advisors/Committee Members: Labrosse, Stéphane (thesis director).

Subjects/Keywords: Graine; Noyau; Dynamique; Observations sismiques; Anisotropie sismique; Inner core; Core; Dynamics; Seismic observation; Seismic anisotropy

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APA (6^th Edition):

Lasbleis, M. (2014). Dynamique et évolution de la graine terrestre : Dynamics and evolution of the Earth’s inner core. (Doctoral Dissertation). Lyon, École normale supérieure. Retrieved from http://www.theses.fr/2014ENSL0962

Chicago Manual of Style (16^th Edition):

Lasbleis, Marine. “Dynamique et évolution de la graine terrestre : Dynamics and evolution of the Earth’s inner core.” 2014. Doctoral Dissertation, Lyon, École normale supérieure. Accessed January 27, 2021. http://www.theses.fr/2014ENSL0962.

MLA Handbook (7^th Edition):

Lasbleis, Marine. “Dynamique et évolution de la graine terrestre : Dynamics and evolution of the Earth’s inner core.” 2014. Web. 27 Jan 2021.

Vancouver:

Lasbleis M. Dynamique et évolution de la graine terrestre : Dynamics and evolution of the Earth’s inner core. [Internet] [Doctoral dissertation]. Lyon, École normale supérieure; 2014. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2014ENSL0962.

Council of Science Editors:

Lasbleis M. Dynamique et évolution de la graine terrestre : Dynamics and evolution of the Earth’s inner core. [Doctoral Dissertation]. Lyon, École normale supérieure; 2014. Available from: http://www.theses.fr/2014ENSL0962

4. Kang, Ming-Fang. INVESTIGATION OF PASSIVE CYCLONIC GAS-LIQUID SEPARATOR PERFORMANCE FOR MICROGRAVITY APPLICATIONS.

Degree: PhD, EMC - Mechanical Engineering, 2017, Case Western Reserve University School of Graduate Studies

URL: http://rave.ohiolink.edu/etdc/view?acc_num=case1481295717930627

► Gas-liquid separation is a key task for various systems that are utilized onboard the International Space Station, such as active thermal control and waste management.… (more)

▼ Gas-liquid separation is a key task for various systems that are utilized onboard the International Space Station, such as active thermal control and waste management. In most of these system designs, performance is either significantly degraded or the equipment undergoes increased wear if two phase flow is not first separated.Unlike being under the influence of Earth gravity, where gas and liquid separate spontaneously due to buoyancy forces, gas bubbles remain suspended within the liquid under microgravity conditions. In the passive cyclonic separator studied in this research, the gas-liquid mixture is separated by the centrifugal force created by tangentially injecting the two phase fluid into a cylindrical housing. The inertia of the flow itself creates a swirling motion which generates the centrifugal acceleration. Due to the density differences between the two phases, the lower density gas phase moves towards the center of rotation creating a gas core surrounded by an annular liquid film.In such an operation, the separation efficiency is strongly influenced by the gas core behavior and the transport of bubbles within the turbulent liquid annulus. The main focus of the present study is to obtain physical insight into the gas core behavior as well as the bubble dynamics within the liquid film through experimentation and computational modeling.The experimental portion of this work entails the construction and operation of a specific cyclonic two phase separator operated across its useful parameter range under the influence of Earth gravity. The useful operating ranges and separation efficiencies are mapped. The numerical modeling work includes two hybrid-multiphase computational fluid dynamics techniques coupled with large eddy simulation turbulence modeling and are implemented by using the OpenFOAM library.Data analysis and comparison reveal that the injection nozzle design, swirl number, and volumetric gas quality all have a major influence on the gas core size. The control volume analysis reveals the importance of the skin friction coefficient. The trajectories of single gas bubbles are simulated numerically and graphed. It is found that fluid turbulence tends to disperse small gas bubbles in the liquid film resulting in a longer residence time. Advisors/Committee Members: Kamotani, Yasuhiro (Advisor), Kadambi, Jaikrishnan (Advisor).

Subjects/Keywords: Mechanical Engineering; Fluid Dynamics; passive cyclonic gas-liquid separator; gas core; bubble dynamics; OpenFOAM; microgravity

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APA (6^th Edition):

Kang, M. (2017). INVESTIGATION OF PASSIVE CYCLONIC GAS-LIQUID SEPARATOR PERFORMANCE FOR MICROGRAVITY APPLICATIONS. (Doctoral Dissertation). Case Western Reserve University School of Graduate Studies. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=case1481295717930627

Chicago Manual of Style (16^th Edition):

Kang, Ming-Fang. “INVESTIGATION OF PASSIVE CYCLONIC GAS-LIQUID SEPARATOR PERFORMANCE FOR MICROGRAVITY APPLICATIONS.” 2017. Doctoral Dissertation, Case Western Reserve University School of Graduate Studies. Accessed January 27, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1481295717930627.

MLA Handbook (7^th Edition):

Kang, Ming-Fang. “INVESTIGATION OF PASSIVE CYCLONIC GAS-LIQUID SEPARATOR PERFORMANCE FOR MICROGRAVITY APPLICATIONS.” 2017. Web. 27 Jan 2021.

Vancouver:

Kang M. INVESTIGATION OF PASSIVE CYCLONIC GAS-LIQUID SEPARATOR PERFORMANCE FOR MICROGRAVITY APPLICATIONS. [Internet] [Doctoral dissertation]. Case Western Reserve University School of Graduate Studies; 2017. [cited 2021 Jan 27]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=case1481295717930627.

Council of Science Editors:

Kang M. INVESTIGATION OF PASSIVE CYCLONIC GAS-LIQUID SEPARATOR PERFORMANCE FOR MICROGRAVITY APPLICATIONS. [Doctoral Dissertation]. Case Western Reserve University School of Graduate Studies; 2017. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=case1481295717930627

University of Wisconsin – Milwaukee

5. Grunzke, Caleb Todd. Predictability and Dynamics of Warm-Core Mesoscale Vortex Formation with the 8 May 2009 "Super Derecho" Event.

Degree: MS, Mathematics, 2016, University of Wisconsin – Milwaukee

URL: https://dc.uwm.edu/etd/1146

► The predictability and dynamics of the warm-core mesovortex associated with the northern-flank of the 8 May 2009 “Super Derecho” event are examined by coupling… (more)

Subjects/Keywords: Derecho; Dynamics; May 8; 2009; Mesovortex; Predictability; Warm-core; Atmospheric Sciences

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APA (6^th Edition):

Grunzke, C. T. (2016). Predictability and Dynamics of Warm-Core Mesoscale Vortex Formation with the 8 May 2009 "Super Derecho" Event. (Thesis). University of Wisconsin – Milwaukee. Retrieved from https://dc.uwm.edu/etd/1146

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Grunzke, Caleb Todd. “Predictability and Dynamics of Warm-Core Mesoscale Vortex Formation with the 8 May 2009 "Super Derecho" Event.” 2016. Thesis, University of Wisconsin – Milwaukee. Accessed January 27, 2021. https://dc.uwm.edu/etd/1146.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Grunzke, Caleb Todd. “Predictability and Dynamics of Warm-Core Mesoscale Vortex Formation with the 8 May 2009 "Super Derecho" Event.” 2016. Web. 27 Jan 2021.

Vancouver:

Grunzke CT. Predictability and Dynamics of Warm-Core Mesoscale Vortex Formation with the 8 May 2009 "Super Derecho" Event. [Internet] [Thesis]. University of Wisconsin – Milwaukee; 2016. [cited 2021 Jan 27]. Available from: https://dc.uwm.edu/etd/1146.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Grunzke CT. Predictability and Dynamics of Warm-Core Mesoscale Vortex Formation with the 8 May 2009 "Super Derecho" Event. [Thesis]. University of Wisconsin – Milwaukee; 2016. Available from: https://dc.uwm.edu/etd/1146

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

6. Winardi, Leonard. Procedures for predicting pressures inside cores.

Degree: PhD, 2007, University of Alabama – Birmingham

URL: http://contentdm.mhsl.uab.edu/u?/etd,540

►

Core gas defects are among the most aggravating defects because they are difficult to control and may not be found until castings are machined. These… (more)

▼

Core gas defects are among the most aggravating defects because they are difficult to control and may not be found until castings are machined. These defects occur when the pressure in the core is higher than the external pressure acting on the core from the metal-head pressure. The prediction of core and mold gas defects requires a determination of the permeability of the cores and the rate and volume of gas evolved from the cores in contact with molten metal. Techniques were developed for measuring core permeability and gas evolution. Gas permeability was measured at pressure levels that are seen inside cores during casting. The volume and rate of gas evolution from cores submerged in molten metal was also measured. Use of these techniques was demonstrated on commercial cores that were submerged in molten aluminum and iron. The effects of common core-making variables and casting temperatures were determined. Permeability depended mainly on compaction level, with increased density associated with reduced permeability. Coatings decreased permeability, while binder, sand type, and additives had no affect. Gas evolution volumes and rates for cores immersed in molten metal were higher in phenolic urethane cold box cores than in epoxy acrylic cores. Higher binder content, additives, coatings, immersion temperatures, core length, and metal contact area all increased evolved gas volumes and rates. A method for calculating the core pressure in simple geometries was developed and confirmed experimentally. The data generated from the gas evolution measurements were used to build a physical model on binder decomposition and the resultant gas evolution during casting. This model was used to determine the amount of gas evolved from cores at various geometries and temperatures. The model accurately predicted the volume of gas evolved. However, the composition of the gases, the core temperature profile, and more precise interfacial heat transfer and sand thermal conductivity data are also required to match the experimental rate curves.

xvi, 217 p. : ill. (some col.), digital, PDF file

Materials Science and Engineering

Engineering;

Core Gas Pressure Defect Sand Casting

UNRESTRICTED

Advisors/Committee Members: Griffin. Robin D., Andrews, J. Barry <br>, Janowski, Gregg M. <br>, Walsh, Peter M. <br>, Viswanathan, Srinath <br>, Littleton, Harry E..

Subjects/Keywords: Core materials – Fluid dynamics – Mathematical models <; br>; Core materials – Permeability <; br>; Metal castings – Defects

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Winardi, L. (2007). Procedures for predicting pressures inside cores. (Doctoral Dissertation). University of Alabama – Birmingham. Retrieved from http://contentdm.mhsl.uab.edu/u?/etd,540

Chicago Manual of Style (16^th Edition):

Winardi, Leonard. “Procedures for predicting pressures inside cores.” 2007. Doctoral Dissertation, University of Alabama – Birmingham. Accessed January 27, 2021. http://contentdm.mhsl.uab.edu/u?/etd,540.

MLA Handbook (7^th Edition):

Winardi, Leonard. “Procedures for predicting pressures inside cores.” 2007. Web. 27 Jan 2021.

Vancouver:

Winardi L. Procedures for predicting pressures inside cores. [Internet] [Doctoral dissertation]. University of Alabama – Birmingham; 2007. [cited 2021 Jan 27]. Available from: http://contentdm.mhsl.uab.edu/u?/etd,540.

Council of Science Editors:

Winardi L. Procedures for predicting pressures inside cores. [Doctoral Dissertation]. University of Alabama – Birmingham; 2007. Available from: http://contentdm.mhsl.uab.edu/u?/etd,540

7. Szelestey, Peter. Computational Modelling of Fracture and Dislocations.

Degree: 2005, Helsinki University of Technology

URL: http://lib.tkk.fi/Diss/2005/isbn9512275007/

►

Mechanical properties of solids bear great significance because of their importance in various fields of engineering and materials science. Fracture and plasticity are the two… (more)

▼

Mechanical properties of solids bear great significance because of their importance in various fields of engineering and materials science. Fracture and plasticity are the two characteristic mechanisms by which materials permanently deform under external loading. Beside experiments and theoretical model calculation computational modelling greatly contributes to the understanding of these phenomena. This dissertation consists of various studies of topics related to these fields. First, the branching instability of dynamic fracture is studied in a simple lattice model which describes a brittle material at mesoscopic length-scales. It is shown that the presence of anisotropy leads to a variation in the fracture pattern and crack tip velocity oscillations. The second part of the thesis consists of atomic level computational modelling of dislocations using molecular dynamics method. Here, the interatomic potential plays a definite and relevant role. For that reason a semi-empirical, many-body embedded-atom potential is developed which turns out to be especially suitable for dislocation studies in fcc crystals, because of the realistic stacking-fault energies it predicts. Dislocation properties at the atomic level determine the micro-structure and in turn the plastic properties of materials. The static dislocation core structure is determined for dissociated dislocations in nickel and compared to analytical calculations. Furthermore, the effective Peierls stress, characterizing the dislocation mobility, and the variation in the dislocation structure through its motion is investigated for the screw orientation as a function of the separation distance of partials. Finally, the interaction of a dissociated screw dislocation and a vacancy type stacking-fault tetrahedron is studied. A wide variety of dislocation processes are found including bending and jog line formation, depending on the internal structure of the dislocation, the orientation and position of the defect.

Helsinki University of Technology Laboratory of Computational Engineering publications. Report B, ISSN 1455-0474; 45

Advisors/Committee Members: Helsinki University of Technology, Department of Electrical and Communications Engineering, Laboratory of Computational Engineering.

Subjects/Keywords: branching instability; molecular dynamics; EAM potential; dislocation core structure; Peierls stress; dislocation-defect interaction

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APA (6^th Edition):

Szelestey, P. (2005). Computational Modelling of Fracture and Dislocations. (Thesis). Helsinki University of Technology. Retrieved from http://lib.tkk.fi/Diss/2005/isbn9512275007/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Szelestey, Peter. “Computational Modelling of Fracture and Dislocations.” 2005. Thesis, Helsinki University of Technology. Accessed January 27, 2021. http://lib.tkk.fi/Diss/2005/isbn9512275007/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Szelestey, Peter. “Computational Modelling of Fracture and Dislocations.” 2005. Web. 27 Jan 2021.

Vancouver:

Szelestey P. Computational Modelling of Fracture and Dislocations. [Internet] [Thesis]. Helsinki University of Technology; 2005. [cited 2021 Jan 27]. Available from: http://lib.tkk.fi/Diss/2005/isbn9512275007/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Szelestey P. Computational Modelling of Fracture and Dislocations. [Thesis]. Helsinki University of Technology; 2005. Available from: http://lib.tkk.fi/Diss/2005/isbn9512275007/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Brigham Young University

8. Shaw, Ryan Phillip. Application of Subjective Logic to Vortex Core Line Extraction and Tracking from Unsteady Computational Fluid Dynamics Simulations.

Degree: MS, 2012, Brigham Young University

URL: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3988&context=etd

► Presented here is a novel tool to extract and track believable vortex core lines from unsteady Computational Fluid Dynamics data sets using multiple feature extraction… (more)

▼ Presented here is a novel tool to extract and track believable vortex core lines from unsteady Computational Fluid Dynamics data sets using multiple feature extraction algorithms. Existing work explored the possibility of extracting features concurrent with a running simulation using intelligent software agents, combining multiple algorithms' capabilities using subjective logic. This work modifies the steady-state approach to work with unsteady fluid dynamics and is designed to work within the Concurrent Agent-enabled Feature Extraction concept. Each agent's belief tuple is quantified using a predefined set of information. The information and functions necessary to set each component in each agent's belief tuple is given along with an explanation of the methods for setting the components. This method is applied to the analyses of flow in a lid-driven cavity and flow around a cylinder, which highlight strengths and weaknesses of the chosen algorithms and the potential for subjective logic to aid in understanding the resulting features. Feature tracking is successfully applied and is observed to have a significant impact on the opinion of the vortex core lines. In the lid-driven cavity data set, unsteady feature extraction modifications are shown to impact feature extraction results with moving vortex core lines. The Sujudi-Haimes algorithm is shown to be more believable when extracting the main vortex core lines of the cavity simulation while the Roth-Peikert algorithm succeeding in extracting the weaker vortex cores in the same simulation. Mesh type and time step is shown to have a significant effect on the method. In the curved wake of the cylinder data set, the Roth-Peikert algorithm more reliably detects vortex core lines which exist for a significant amount of time. the method was finally applied to a massive wind turbine simulation, where the importance of performing feature extraction in parallel is shown. The use of multiple extraction algorithms with subjective logic and feature tracking helps determine the expected probability that an extracted vortex core is believable. This approach may be applied to massive data sets which will greatly reduce analysis time and data size and will aid in a greater understanding of complex fluid flows.

Subjects/Keywords: Feature Extraction; Feature Tracking; Vortex Core Lines; Computational Fluid Dynamics; Subjective Logic; Mechanical Engineering

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APA (6^th Edition):

Shaw, R. P. (2012). Application of Subjective Logic to Vortex Core Line Extraction and Tracking from Unsteady Computational Fluid Dynamics Simulations. (Masters Thesis). Brigham Young University. Retrieved from https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3988&context=etd

Chicago Manual of Style (16^th Edition):

Shaw, Ryan Phillip. “Application of Subjective Logic to Vortex Core Line Extraction and Tracking from Unsteady Computational Fluid Dynamics Simulations.” 2012. Masters Thesis, Brigham Young University. Accessed January 27, 2021. https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3988&context=etd.

MLA Handbook (7^th Edition):

Shaw, Ryan Phillip. “Application of Subjective Logic to Vortex Core Line Extraction and Tracking from Unsteady Computational Fluid Dynamics Simulations.” 2012. Web. 27 Jan 2021.

Vancouver:

Shaw RP. Application of Subjective Logic to Vortex Core Line Extraction and Tracking from Unsteady Computational Fluid Dynamics Simulations. [Internet] [Masters thesis]. Brigham Young University; 2012. [cited 2021 Jan 27]. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3988&context=etd.

Council of Science Editors:

Shaw RP. Application of Subjective Logic to Vortex Core Line Extraction and Tracking from Unsteady Computational Fluid Dynamics Simulations. [Masters Thesis]. Brigham Young University; 2012. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3988&context=etd

Tampere University

9. Garomssa, Habtamu Diriba. The state of entrepreneurialism in a public university in Ethiopia: Status, challenges and opportunities .

Degree: 2016, Tampere University

URL: https://trepo.tuni.fi/handle/10024/99635

► Over the past few decades the entrepreneurial university model has emerged as mechanism of maintaining balance with the increasingly shifting HE environment. Against this background… (more)

Subjects/Keywords: entrepreneurial university; dynamics; knowledge transfer; steering core; development periphery; academic heartland; culture; diversification.

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APA (6^th Edition):

Garomssa, H. D. (2016). The state of entrepreneurialism in a public university in Ethiopia: Status, challenges and opportunities . (Masters Thesis). Tampere University. Retrieved from https://trepo.tuni.fi/handle/10024/99635

Chicago Manual of Style (16^th Edition):

Garomssa, Habtamu Diriba. “The state of entrepreneurialism in a public university in Ethiopia: Status, challenges and opportunities .” 2016. Masters Thesis, Tampere University. Accessed January 27, 2021. https://trepo.tuni.fi/handle/10024/99635.

MLA Handbook (7^th Edition):

Garomssa, Habtamu Diriba. “The state of entrepreneurialism in a public university in Ethiopia: Status, challenges and opportunities .” 2016. Web. 27 Jan 2021.

Vancouver:

Garomssa HD. The state of entrepreneurialism in a public university in Ethiopia: Status, challenges and opportunities . [Internet] [Masters thesis]. Tampere University; 2016. [cited 2021 Jan 27]. Available from: https://trepo.tuni.fi/handle/10024/99635.

Council of Science Editors:

Garomssa HD. The state of entrepreneurialism in a public university in Ethiopia: Status, challenges and opportunities . [Masters Thesis]. Tampere University; 2016. Available from: https://trepo.tuni.fi/handle/10024/99635

University of Exeter

10. Hole, Nicola. The policy implications of everyday energy consumption : the meanings, temporal rhythms and social dynamics of energy use.

Degree: PhD, 2014, University of Exeter

URL: http://hdl.handle.net/10871/16551

► Traditional research into pro-environmental behaviour change has a tendency to be focussed on either the context in which practices are enacted or the cognitive processes… (more)

Subjects/Keywords: 550; Energy policy; Energy consumption; Practice Theory; Social dynamics; Social capital; Core economy

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APA (6^th Edition):

Hole, N. (2014). The policy implications of everyday energy consumption : the meanings, temporal rhythms and social dynamics of energy use. (Doctoral Dissertation). University of Exeter. Retrieved from http://hdl.handle.net/10871/16551

Chicago Manual of Style (16^th Edition):

Hole, Nicola. “The policy implications of everyday energy consumption : the meanings, temporal rhythms and social dynamics of energy use.” 2014. Doctoral Dissertation, University of Exeter. Accessed January 27, 2021. http://hdl.handle.net/10871/16551.

MLA Handbook (7^th Edition):

Hole, Nicola. “The policy implications of everyday energy consumption : the meanings, temporal rhythms and social dynamics of energy use.” 2014. Web. 27 Jan 2021.

Vancouver:

Hole N. The policy implications of everyday energy consumption : the meanings, temporal rhythms and social dynamics of energy use. [Internet] [Doctoral dissertation]. University of Exeter; 2014. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10871/16551.

Council of Science Editors:

Hole N. The policy implications of everyday energy consumption : the meanings, temporal rhythms and social dynamics of energy use. [Doctoral Dissertation]. University of Exeter; 2014. Available from: http://hdl.handle.net/10871/16551

University of Washington

11. Lee, Andrew J. Real-Time Core-Hole Dynamics in X-ray Spectroscopy.

Degree: PhD, 2015, University of Washington

URL: http://hdl.handle.net/1773/27560

► While experimental developments have enabled the study of core-hole dynamics in X-ray spectroscopy, theoretical methods for dynamical effects are still underdeveloped. Additionally, traditional theoretical methods… (more)

Subjects/Keywords: core-hole; dynamics; real-time; TDDFT; XANES; XAS; Condensed matter physics; Quantum physics; Physics; physics

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APA (6^th Edition):

Lee, A. J. (2015). Real-Time Core-Hole Dynamics in X-ray Spectroscopy. (Doctoral Dissertation). University of Washington. Retrieved from http://hdl.handle.net/1773/27560

Chicago Manual of Style (16^th Edition):

Lee, Andrew J. “Real-Time Core-Hole Dynamics in X-ray Spectroscopy.” 2015. Doctoral Dissertation, University of Washington. Accessed January 27, 2021. http://hdl.handle.net/1773/27560.

MLA Handbook (7^th Edition):

Lee, Andrew J. “Real-Time Core-Hole Dynamics in X-ray Spectroscopy.” 2015. Web. 27 Jan 2021.

Vancouver:

Lee AJ. Real-Time Core-Hole Dynamics in X-ray Spectroscopy. [Internet] [Doctoral dissertation]. University of Washington; 2015. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/1773/27560.

Council of Science Editors:

Lee AJ. Real-Time Core-Hole Dynamics in X-ray Spectroscopy. [Doctoral Dissertation]. University of Washington; 2015. Available from: http://hdl.handle.net/1773/27560

12. Hellio, Gabrielle. Modèles stochastiques de mesures archéomagnétiques : Stochastic modeling of archeomagnetic measurements.

Degree: Docteur es, Terre solide, 2015, Université Grenoble Alpes (ComUE)

URL: http://www.theses.fr/2015GREAU004

►

Cette thèse porte sur la construction de modèles stochastiques, régionaux et globaux du champ magnétique sur les quatre derniers millénaires à l'aide de mesures archéomagnétiques.… (more)

▼

Cette thèse porte sur la construction de modèles stochastiques, régionaux et globaux du champ magnétique sur les quatre derniers millénaires à l'aide de mesures archéomagnétiques. Ces données présentent une répartition spatiale et temporelle très inhomogène, et sont caractérisées par de fortes incertitudes sur la mesure et sur la date. La reconstruction du champ constitue alors un problème inverse mal posé. Afin de déterminer la solution la plus adaptée, une information a priori sur le modèle doit être choisie. Elle consiste généralement en une régularisation arbitraire du champ magnétique (lissage en temps et en espace). Contrairement aux études précédentes, nous utilisons les statistiques temporelles du champ magnétique, dérivées des données d'observatoires, satellitaires et paléomagnétiques pour définir l'information a priori via des fonctions d'auto-covariances. Ces statistiques sont confirmées par des résultats issus de simulations numériques. Cette méthode bayésienne permet de s'affranchir de l'utilisation de fonctions supports arbitraires comme les splines pour l'interpolation temporelle. Le résultat final consiste en un ensemble de réalisations possibles du champ magnétique dont la dispersion caractérise l'incertitude sur le modèle. Afin de prendre en compte les erreurs de datation, nous développons par ailleurs une méthode basée sur l'utilisation de Markov Chain Monte Carlo (MCMC). Elle nous permet d'explorer de manière efficace l'espace des dates possibles et ainsi de sélectionner les modèles les plus probables. Cette méthode est une amélioration de la méthode de bootstrap classique, qui donne le même poids à des tirages aléatoires de dates présentant des probabilités très variables. Les ensembles de réalisations sélectionnés par la méthode MCMC aboutissent à la construction d'une densité de probabilités en lieu et place d'une courbe unique. La méthode bayésienne combinée à la méthode Markov Chain Monte Carlo nous a permis de construire des courbes régionales présentant des variations plus rapides que celles obtenues par d'autres études. Les courbes représentées sous forme de densités de probabilités ne sont pas nécessairement gaussiennes, et la méthode permet d'affiner l'estimation de l'âge de chacune des observations. La méthode bayésienne a été utilisée pour la construction de modèles globaux pour lesquels le dipôle axial présente des variations plus rapides que celui obtenu par de précédentes études. D'autre part, le champ magnétique obtenu pour les époques les plus récentes est raisonnablement similaire à celui construit à partir de mesures directes (satellites, observatoires, historiques) malgré des données beaucoup moins nombreuses et une répartition beaucoup moins homogène. Les modèles issus de cette étude offrent une alternative aux modèles existants régularisés, et pourront servir dans un objectif d'assimilation de données avec des modèles de la dynamique dans le noyau terrestre.

The aim of this thesis is to build stochastic models of the magnetic field for the last four millenia from…

Advisors/Committee Members: Jault, Dominique (thesis director), Gillet, Nicolas (thesis director), Bouligand, Claire (thesis director).

Subjects/Keywords: Géomagnétisme; Dynamique du noyau; Problème inverse; Archéomagnétisme; Geomagnetism; Core dynamics; Inverse problem; Archeomagnetism; 550

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hellio, G. (2015). Modèles stochastiques de mesures archéomagnétiques : Stochastic modeling of archeomagnetic measurements. (Doctoral Dissertation). Université Grenoble Alpes (ComUE). Retrieved from http://www.theses.fr/2015GREAU004

Chicago Manual of Style (16^th Edition):

Hellio, Gabrielle. “Modèles stochastiques de mesures archéomagnétiques : Stochastic modeling of archeomagnetic measurements.” 2015. Doctoral Dissertation, Université Grenoble Alpes (ComUE). Accessed January 27, 2021. http://www.theses.fr/2015GREAU004.

MLA Handbook (7^th Edition):

Hellio, Gabrielle. “Modèles stochastiques de mesures archéomagnétiques : Stochastic modeling of archeomagnetic measurements.” 2015. Web. 27 Jan 2021.

Vancouver:

Hellio G. Modèles stochastiques de mesures archéomagnétiques : Stochastic modeling of archeomagnetic measurements. [Internet] [Doctoral dissertation]. Université Grenoble Alpes (ComUE); 2015. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2015GREAU004.

Council of Science Editors:

Hellio G. Modèles stochastiques de mesures archéomagnétiques : Stochastic modeling of archeomagnetic measurements. [Doctoral Dissertation]. Université Grenoble Alpes (ComUE); 2015. Available from: http://www.theses.fr/2015GREAU004

13. Loudon, Andrew Howard. Microbial dynamics and core microbiome of red-backed salamanders (Plethodon cinereus).

Degree: 2013, James Madison University

URL: https://commons.lib.jmu.edu/master201019/263

► Beneficial cutaneous bacteria on amphibians can protect against the lethal fungal disease chytridiomycosis, which has decimated many amphibian species. The stability of these bacterial communities… (more)

Subjects/Keywords: community dynamics; core microbiome; host-bacteria interactions; microbiomes; Plethodon cinereus; Batrachochytrium dendrobatidis; Biology

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APA (6^th Edition):

Loudon, A. H. (2013). Microbial dynamics and core microbiome of red-backed salamanders (Plethodon cinereus). (Masters Thesis). James Madison University. Retrieved from https://commons.lib.jmu.edu/master201019/263

Chicago Manual of Style (16^th Edition):

Loudon, Andrew Howard. “Microbial dynamics and core microbiome of red-backed salamanders (Plethodon cinereus).” 2013. Masters Thesis, James Madison University. Accessed January 27, 2021. https://commons.lib.jmu.edu/master201019/263.

MLA Handbook (7^th Edition):

Loudon, Andrew Howard. “Microbial dynamics and core microbiome of red-backed salamanders (Plethodon cinereus).” 2013. Web. 27 Jan 2021.

Vancouver:

Loudon AH. Microbial dynamics and core microbiome of red-backed salamanders (Plethodon cinereus). [Internet] [Masters thesis]. James Madison University; 2013. [cited 2021 Jan 27]. Available from: https://commons.lib.jmu.edu/master201019/263.

Council of Science Editors:

Loudon AH. Microbial dynamics and core microbiome of red-backed salamanders (Plethodon cinereus). [Masters Thesis]. James Madison University; 2013. Available from: https://commons.lib.jmu.edu/master201019/263

University of Maryland

14. Triana, Santiago Andres. Inertial waves in a laboratory model of the Earth's core.

Degree: Physics, 2011, University of Maryland

URL: http://hdl.handle.net/1903/11480

► A water-filled three-meter diameter spherical shell built as a model of the Earth's core shows evidence of precessionally forced flows and, when spinning the inner… (more)

Subjects/Keywords: Physics; Geophysics; fluid dynamics; inertial waves; liquid core; precession; rotation; spherical-Couette

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APA (6^th Edition):

Triana, S. A. (2011). Inertial waves in a laboratory model of the Earth's core. (Thesis). University of Maryland. Retrieved from http://hdl.handle.net/1903/11480

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Triana, Santiago Andres. “Inertial waves in a laboratory model of the Earth's core.” 2011. Thesis, University of Maryland. Accessed January 27, 2021. http://hdl.handle.net/1903/11480.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Triana, Santiago Andres. “Inertial waves in a laboratory model of the Earth's core.” 2011. Web. 27 Jan 2021.

Vancouver:

Triana SA. Inertial waves in a laboratory model of the Earth's core. [Internet] [Thesis]. University of Maryland; 2011. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/1903/11480.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Triana SA. Inertial waves in a laboratory model of the Earth's core. [Thesis]. University of Maryland; 2011. Available from: http://hdl.handle.net/1903/11480

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

15. Cruz, Fabiana Sanches. Estudo do escoamento de gás no interior de ciclones através da técnica de fluidodinâmica computacional.

Degree: Mestrado, Engenharia Química, 2013, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/3/3137/tde-30072013-220253/ ;

►

Neste trabalho, buscou-se investigar a aplicação de uma modelagem RANS, com a utilização do modelo de turbulência das Tensões de Reynolds (RSTM), na modelagem do… (more)

▼

Neste trabalho, buscou-se investigar a aplicação de uma modelagem RANS, com a utilização do modelo de turbulência das Tensões de Reynolds (RSTM), na modelagem do escoamento de gás no interior de ciclones, especialmente na simulação do movimento periódico do vórtice, conhecido como Precessing Vortex Core (PVC), com apoio da Fluidodinâmica Computacional. Utilizou-se o pacote de CFD de código aberto OpenFOAM, e as simulações foram realizadas em regime transiente. Dois modelos RSTM foram testados, o modelo LRR com os valores padrões para as constantes e uma modificação das constantes do termo de redistribuição. Compararam-se os resultados obtidos com dados da literatura e verificou-se que ambos os modelos representaram o campo médio de velocidade. No entanto, somente o modelo LRR conseguiu reproduzir o campo de flutuações de velocidade. Detectou-se o movimento de precessão do vórtice, que pode ser visualizado através de imagens sequenciais do escoamento, e uma frequência característica do movimento pode ser calculada através do Espectro de potência.

The flow field of a gas cyclone was simulated with a RANS model using Computational Fluid Dynamics (CFD) and the Precession of the Vortex Core (PVC) was investigated. The CFD simulations were carried out using the open source code OpenFOAM and the simulations were performed in a transient regime. Two Reynolds Stress Turbulence Models (RSTM) were investigated - the LRR model with standard constants and another with modified constants in the pressure-strain term. The results obtained by the models were compared with values of mean velocity taken from the literature and predictions were satisfactory. However, only the LRR model with standard constants predicted with precision the fluctuation velocity field. The precessing vortex was detected and illustrated by the flow field visualization and a characteristic frequency was calculated by Power Spectrum Density.

Advisors/Committee Members: Paiva, José Luis de.

Subjects/Keywords: Ciclone; Computational fluid dynamics; Cyclone; Fluidodinâmica computacional; Modelos de turbulência; Precessing vortex core; Turbulence; Turbulence models; Turbulência; Vórtice de precessão

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APA (6^th Edition):

Cruz, F. S. (2013). Estudo do escoamento de gás no interior de ciclones através da técnica de fluidodinâmica computacional. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/3/3137/tde-30072013-220253/ ;

Chicago Manual of Style (16^th Edition):

Cruz, Fabiana Sanches. “Estudo do escoamento de gás no interior de ciclones através da técnica de fluidodinâmica computacional.” 2013. Masters Thesis, University of São Paulo. Accessed January 27, 2021. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-30072013-220253/ ;.

MLA Handbook (7^th Edition):

Cruz, Fabiana Sanches. “Estudo do escoamento de gás no interior de ciclones através da técnica de fluidodinâmica computacional.” 2013. Web. 27 Jan 2021.

Vancouver:

Cruz FS. Estudo do escoamento de gás no interior de ciclones através da técnica de fluidodinâmica computacional. [Internet] [Masters thesis]. University of São Paulo; 2013. [cited 2021 Jan 27]. Available from: http://www.teses.usp.br/teses/disponiveis/3/3137/tde-30072013-220253/ ;.

Council of Science Editors:

Cruz FS. Estudo do escoamento de gás no interior de ciclones através da técnica de fluidodinâmica computacional. [Masters Thesis]. University of São Paulo; 2013. Available from: http://www.teses.usp.br/teses/disponiveis/3/3137/tde-30072013-220253/ ;

University of Michigan

16. Das, Sambit. Large Scale Electronic Structure Studies on the Energetics of Dislocations in Al-Mg Materials System and Its Connection to Mesoscale Models.

Degree: PhD, Mechanical Engineering, 2019, University of Michigan

URL: http://hdl.handle.net/2027.42/153417

► Computational modeling of dislocation behavior is vital for designing new lightweight metallic alloys. However, extraordinary challenges are posed by the multiscale physics ranging over a… (more)

▼ Computational modeling of dislocation behavior is vital for designing new lightweight metallic alloys. However, extraordinary challenges are posed by the multiscale physics ranging over a vast span of interacting length-scales from electronic-structure and atomic-scale effects at the dislocation core (< 10^-9 {rm m}) to long-ranged elastic interactions at the continuum scale (sim 10 upmu). In particular, quantification of the energetics associated with electronic-structure effects inside the dislocation core and its interaction with the external macroscopic elastic fields have not been explored due to limitations of current electronic-structure methods based on the widely used plane-wave based discretization. This thesis seeks to address the above challenges by developing computational methodologies to conduct large-scale real-space electronic-structure studies of energetics of dislocations in Aluminum and Magnesium, and use these results to develop phenomenological connections to mesoscale models of plasticity like discrete dislocation dynamics (DDD), which study the collective behavior of the dislocations at longer length scales (sim 1 – 15 upmu). First, a local real-space formulation of orbital-free Density Functional Theory is developed based on prior work, and implemented using finite-element discretization. The local real-space formulation coupled with bulk Dirichlet boundary conditions enables a direct computation of the isolated dislocation core energy. Studies on dislocations in Aluminum and Magnesium suggest that the core-size – region with significant contribution of electronic effects to dislocation energetics – is around seven to eleven times the magnitude of the Burgers vector. This is in stark contrast to prior displacement field based core size estimates of one to three times the magnitude of the Burgers vector. Interestingly, our study further indicates that the core-energy of the dislocations in both Aluminum and Magnesium is strongly dependent on external macroscopic strains with a non-zero slope at zero external strain. Next, the computed dislocation core energetics is used to develop a continuum model for an arbitrary aggregate of dislocations in an infinite isotropic elastic continua. This model, which accounts for the core energy dependence on macroscopic deformation provides a phenomenological approach to incorporate the electronic structure effects into mesoscale DDD simulations. Application of this model to derive nodal forces in a discrete dislocation network, leads to additional configurational forces beyond those considered in existing DDD models. Using case studies, we show that even up to distances of 10-15 nm between the dislocations, these additional configurational forces are non-trivial in relation to the elastic Peach-Koehler force. Furthermore, the core force model is incorporated into a DDD implementation, where significant influence of core force on elementary dislocation mechanisms in Aluminum such as critical stress of a Frank-Read source and structure of a… Advisors/Committee Members: Gavini, Vikram (committee member), Qi, Liang (committee member), Aubry, Sylvie (committee member), Garikipati, Krishnakumar R (committee member).

Subjects/Keywords: Electronic structure; Real-space; Finite-elements; Dislocation core; Discrete dislocation dynamics; Materials Science and Engineering; Mechanical Engineering; Engineering

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APA (6^th Edition):

Das, S. (2019). Large Scale Electronic Structure Studies on the Energetics of Dislocations in Al-Mg Materials System and Its Connection to Mesoscale Models. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/153417

Chicago Manual of Style (16^th Edition):

Das, Sambit. “Large Scale Electronic Structure Studies on the Energetics of Dislocations in Al-Mg Materials System and Its Connection to Mesoscale Models.” 2019. Doctoral Dissertation, University of Michigan. Accessed January 27, 2021. http://hdl.handle.net/2027.42/153417.

MLA Handbook (7^th Edition):

Das, Sambit. “Large Scale Electronic Structure Studies on the Energetics of Dislocations in Al-Mg Materials System and Its Connection to Mesoscale Models.” 2019. Web. 27 Jan 2021.

Vancouver:

Das S. Large Scale Electronic Structure Studies on the Energetics of Dislocations in Al-Mg Materials System and Its Connection to Mesoscale Models. [Internet] [Doctoral dissertation]. University of Michigan; 2019. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/2027.42/153417.

Council of Science Editors:

Das S. Large Scale Electronic Structure Studies on the Energetics of Dislocations in Al-Mg Materials System and Its Connection to Mesoscale Models. [Doctoral Dissertation]. University of Michigan; 2019. Available from: http://hdl.handle.net/2027.42/153417

17. Sargant, Robert John. Molecular Dynamics Simulations of Elongated Molecules.

Degree: 2012, University of Manchester

URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:182611

► The existence of a thermotropic biaxial nematic liquid crystal phase has been a topic of great interest for almost half a century. Of the various… (more)

▼ The existence of a thermotropic biaxial nematic liquid crystal phase has been a topic of great interest for almost half a century. Of the various mesogenic shapes suggested as being able to form this phase, theory has suggested that the V-shaped or "bent-core" molecule is one of the most promising candidates. In this thesis we use a simple mesogenic model of a bent-core molecule, constructed from a number of repulsive Weeks-Chandler-Andersen potentials that are assembled into a rigid V shape. Using this model we explore the spontaneous phase behaviour that occurs in a wide array of different systems of mesogens, using molecular dynamics simulations and isotropic initial conditions. We study the relationship between molecular bend angle and phase behavior for molecules constructed from 11 potentials. We find that the phase behaviour splits into two regions, above and below a critical bend angle. Molecules wider than this angle exhibit isotropic, uniaxial nematic and smectic A phases. Narrower molecules show no uniaxially aligned phases, and instead have a clustered phase with short-range ordering and no global alignment director. Increasing system size improves the smectic layering in the wider molecules, but does not affect the global alignment of the narrower molecules. Our model is extended to include the effect of the arm length of the molecule by changing the number of potentials from which the mesogens are constructed. As the molecule is reduced in size, the critical bend angle is seen to move slowly towards more linear molecules, reducing the size of the parameter space in which uniaxial nematic alignment is possible. At 5 beads, all mesophases are seen to disappear and systems remain isotropic. We also study the behaviour of binary mixtures of bent-core molecules, both of differing arm lengths and of differing bend angles. For arm length mixtures, molecules are seen to remain mixed in the isotropic and nematic phases, and phase separate on transition to a smectic phase. In addition, uniaxial nematic phases are induced in systems that have no nematic phase of their own in isolation. For mixtures of different bend angles, systems remain fully mixed in the smectic phases for differences of up to 10 degrees, and beyond this the two components begin to separate at the nematic–smectic transition. Advisors/Committee Members: Masters, Andrew.

Subjects/Keywords: liquid crystals; bent-core; molecular dynamics

…structure of a bent-core mesogenic molecule… …for bent-core molecules in the Onsager limit by Teixeira et al… …for bent-core molecules made from hard spherocylinder dimers with L/D = 5 by Lansac et al… …63 3.1 3.2 8 3.3 A representation of an 11-bead bent-core molecule and a set of… …1.31. . . . . . . . . . . . . . 101 4.1 A front and side view of a 7-bead bent-core…

10 more images…

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APA (6^th Edition):

Sargant, R. J. (2012). Molecular Dynamics Simulations of Elongated Molecules. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:182611

Chicago Manual of Style (16^th Edition):

Sargant, Robert John. “Molecular Dynamics Simulations of Elongated Molecules.” 2012. Doctoral Dissertation, University of Manchester. Accessed January 27, 2021. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:182611.

MLA Handbook (7^th Edition):

Sargant, Robert John. “Molecular Dynamics Simulations of Elongated Molecules.” 2012. Web. 27 Jan 2021.

Vancouver:

Sargant RJ. Molecular Dynamics Simulations of Elongated Molecules. [Internet] [Doctoral dissertation]. University of Manchester; 2012. [cited 2021 Jan 27]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:182611.

Council of Science Editors:

Sargant RJ. Molecular Dynamics Simulations of Elongated Molecules. [Doctoral Dissertation]. University of Manchester; 2012. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:182611

Cranfield University

18. Alagbe, Solomon Oluyemi. Experimental and numerical investigation of high viscosity oil-based multiphase flows.

Degree: PhD, 2013, Cranfield University

URL: http://dspace.lib.cranfield.ac.uk/handle/1826/10495

► Multiphase flows are of great interest to a large variety of industries because flows of two or more immiscible liquids are encountered in a diverse… (more)

Subjects/Keywords: Minimum Transport Condition (MTC); Heavy oil; Water assisted flow; Core annular flow; Computational Fluid Dynamics (CFD); Probability Density Function (PDF)

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APA (6^th Edition):

Alagbe, S. O. (2013). Experimental and numerical investigation of high viscosity oil-based multiphase flows. (Doctoral Dissertation). Cranfield University. Retrieved from http://dspace.lib.cranfield.ac.uk/handle/1826/10495

Chicago Manual of Style (16^th Edition):

Alagbe, Solomon Oluyemi. “Experimental and numerical investigation of high viscosity oil-based multiphase flows.” 2013. Doctoral Dissertation, Cranfield University. Accessed January 27, 2021. http://dspace.lib.cranfield.ac.uk/handle/1826/10495.

MLA Handbook (7^th Edition):

Alagbe, Solomon Oluyemi. “Experimental and numerical investigation of high viscosity oil-based multiphase flows.” 2013. Web. 27 Jan 2021.

Vancouver:

Alagbe SO. Experimental and numerical investigation of high viscosity oil-based multiphase flows. [Internet] [Doctoral dissertation]. Cranfield University; 2013. [cited 2021 Jan 27]. Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/10495.

Council of Science Editors:

Alagbe SO. Experimental and numerical investigation of high viscosity oil-based multiphase flows. [Doctoral Dissertation]. Cranfield University; 2013. Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/10495

Cranfield University

19. Alagbe, Solomon Oluyemi. Experimental and numerical investigation of high viscosity oil-based multiphase flows.

Degree: PhD, 2013, Cranfield University

URL: http://dspace.lib.cranfield.ac.uk/handle/1826/10495 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.693477

► Multiphase flows are of great interest to a large variety of industries because flows of two or more immiscible liquids are encountered in a diverse… (more)

Subjects/Keywords: 620.1; Minimum Transport Condition (MTC); Heavy oil; Water assisted flow; Core annular flow; Computational Fluid Dynamics (CFD); Probability Density Function (PDF)

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Alagbe, S. O. (2013). Experimental and numerical investigation of high viscosity oil-based multiphase flows. (Doctoral Dissertation). Cranfield University. Retrieved from http://dspace.lib.cranfield.ac.uk/handle/1826/10495 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.693477

Chicago Manual of Style (16^th Edition):

Alagbe, Solomon Oluyemi. “Experimental and numerical investigation of high viscosity oil-based multiphase flows.” 2013. Doctoral Dissertation, Cranfield University. Accessed January 27, 2021. http://dspace.lib.cranfield.ac.uk/handle/1826/10495 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.693477.

MLA Handbook (7^th Edition):

Alagbe, Solomon Oluyemi. “Experimental and numerical investigation of high viscosity oil-based multiphase flows.” 2013. Web. 27 Jan 2021.

Vancouver:

Alagbe SO. Experimental and numerical investigation of high viscosity oil-based multiphase flows. [Internet] [Doctoral dissertation]. Cranfield University; 2013. [cited 2021 Jan 27]. Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/10495 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.693477.

Council of Science Editors:

Alagbe SO. Experimental and numerical investigation of high viscosity oil-based multiphase flows. [Doctoral Dissertation]. Cranfield University; 2013. Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/10495 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.693477

University of Florida

20. Cooley, Katie Doone. Defoliation Frequency and Location Effects on Root-Rhizome Mass, Herbage Accumulation, and Canopy Characteristics of Rhizoma Peanut Entries Differing in Growth Habit.

Degree: MS, Agronomy, 2018, University of Florida

URL: https://ufdc.ufl.edu/UFE0054121

► Grasslands occupy nearly 40% of USA land area and, in addition to supplying feed for livestock, provide valuable services to society including storing carbon in… (more)

▼ Grasslands occupy nearly 40% of USA land area and, in addition to supplying feed for livestock, provide valuable services to society including storing carbon in soil, minimizing soil erosion, purifying water by removing excess nutrients, and providing wildlife habitat. Most grasslands in the southeastern US are comprised of warm-climate grass species that are dependent on nitrogen fertilizer and have relatively low nutritional value for livestock. Inclusion of legumes in mixture with grasses can increase nutritive value and benefit nutrient cycling and soil quality. Rhizoma peanut (RP; Arachis glabrata Benth.) is a long-lived legume in the US Gulf Coast Region, providing an array of ecosystem services. Most current RP cultivars were selected for upright growth and hay production, but newer introductions and selections exist that are lower growing with potential for grazing or ornamental use. Data describing key forage responses are lacking for these entries, and evaluation of productivity, nutritive value, and persistence is needed in different soil environments and under different cutting regimes. Also needed is a better understanding of root-rhizome accumulation, which is a large contributor to soil carbon storage. One study compared the response of 14 RP entries to two defoliation frequency treatments, including one harvest per year at season end vs. two harvests per year occurring at mid-season and end of the growing season. A single defoliation event per year resulted in significant reductions in herbage accumulation (HA) and nutritive value for most RP entries relative to harvests at both the middle and end of the growing season. Herbage accumulation was not affected by defoliation frequency for the entry Quincy-Beta, perhaps because of its disease tolerance. Greater defoliation frequency decreased root-rhizome mass and non-structural carbohydrate pool, a response of particular importance to producers using RP fields both for forage and as a source of rhizomes for planting material. A second study compared the 14 RP entries growing in a well-drained soil at Quincy, Florida and in a seasonally flooded soil at Hague, Florida. Well-drained soil at Quincy was more favorable to RP entries in general than seasonally-saturated soil at Hague, which led to many entries having greater HA at Quincy than Hague. The entry Ona 33 had nearly the same HA at both locations, and it is considerably better adapted to seasonally-saturated soils than all RP entries currently being used commercially. A third study reports on the design and use of a modified ingrowth core for measuring root accumulation rate. Increasing the mesh size of the fabric to 4 mm and using a wire frame cage to support the core allowed it to maintain its geometry over 100-d deployment periods and detect differences among RP entries. Finally, results of these studies suggest there is opportunity to select new RP cultivars that are adapted to wetter soils and are well suited for grazing and ornamental uses while maintaining high levels of forage production,… Advisors/Committee Members: SOLLENBERGER,LYNN E (committee chair), DUBEUX,JOSE CARLOS (committee member), SILVEIRA,MARIA LUCIA (committee member).

Subjects/Keywords: arachis – belowground – biomass – carbon – core – cultivar – defoliation – drainage – dynamics – forage – frequency – glabrata – ingrowth – legume – nutritive – peanut – rhizoma – root – soil – value

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APA (6^th Edition):

Cooley, K. D. (2018). Defoliation Frequency and Location Effects on Root-Rhizome Mass, Herbage Accumulation, and Canopy Characteristics of Rhizoma Peanut Entries Differing in Growth Habit. (Masters Thesis). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0054121

Chicago Manual of Style (16^th Edition):

Cooley, Katie Doone. “Defoliation Frequency and Location Effects on Root-Rhizome Mass, Herbage Accumulation, and Canopy Characteristics of Rhizoma Peanut Entries Differing in Growth Habit.” 2018. Masters Thesis, University of Florida. Accessed January 27, 2021. https://ufdc.ufl.edu/UFE0054121.

MLA Handbook (7^th Edition):

Cooley, Katie Doone. “Defoliation Frequency and Location Effects on Root-Rhizome Mass, Herbage Accumulation, and Canopy Characteristics of Rhizoma Peanut Entries Differing in Growth Habit.” 2018. Web. 27 Jan 2021.

Vancouver:

Cooley KD. Defoliation Frequency and Location Effects on Root-Rhizome Mass, Herbage Accumulation, and Canopy Characteristics of Rhizoma Peanut Entries Differing in Growth Habit. [Internet] [Masters thesis]. University of Florida; 2018. [cited 2021 Jan 27]. Available from: https://ufdc.ufl.edu/UFE0054121.

Council of Science Editors:

Cooley KD. Defoliation Frequency and Location Effects on Root-Rhizome Mass, Herbage Accumulation, and Canopy Characteristics of Rhizoma Peanut Entries Differing in Growth Habit. [Masters Thesis]. University of Florida; 2018. Available from: https://ufdc.ufl.edu/UFE0054121

Virginia Tech

21. Ruscio, Jory Zmuda. Molecular Modeling: Elucidation of Structure/Function Relationships of Proteins and DNA at the Atomic Resolution.

Degree: PhD, Genetics, Bioinformatics, and Computational Biology, 2007, Virginia Tech

URL: http://hdl.handle.net/10919/27219

► While experiments provide valuable information about biological molecules, current technology cannot yet monitor atomic fluctuations at relevant time scales. Theoretical computational simulations are able to… (more)

Subjects/Keywords: nucleosome core particle; myoglobin; beta-glucosidases; molecular dynamics

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APA (6^th Edition):

Ruscio, J. Z. (2007). Molecular Modeling: Elucidation of Structure/Function Relationships of Proteins and DNA at the Atomic Resolution. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/27219

Chicago Manual of Style (16^th Edition):

Ruscio, Jory Zmuda. “Molecular Modeling: Elucidation of Structure/Function Relationships of Proteins and DNA at the Atomic Resolution.” 2007. Doctoral Dissertation, Virginia Tech. Accessed January 27, 2021. http://hdl.handle.net/10919/27219.

MLA Handbook (7^th Edition):

Ruscio, Jory Zmuda. “Molecular Modeling: Elucidation of Structure/Function Relationships of Proteins and DNA at the Atomic Resolution.” 2007. Web. 27 Jan 2021.

Vancouver:

Ruscio JZ. Molecular Modeling: Elucidation of Structure/Function Relationships of Proteins and DNA at the Atomic Resolution. [Internet] [Doctoral dissertation]. Virginia Tech; 2007. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10919/27219.

Council of Science Editors:

Ruscio JZ. Molecular Modeling: Elucidation of Structure/Function Relationships of Proteins and DNA at the Atomic Resolution. [Doctoral Dissertation]. Virginia Tech; 2007. Available from: http://hdl.handle.net/10919/27219

University of Texas – Austin

22. Zhang, Liang, 1986. Theoretical study of correlation between structure and function for nanoparticle catalysts.

Degree: PhD, Chemistry, 2014, University of Texas – Austin

URL: http://hdl.handle.net/2152/28338

► The science and technology of catalysis is more important today than at any other time in our history due to the grand energy and environment… (more)

▼ The science and technology of catalysis is more important today than at any other time in our history due to the grand energy and environment challenges we are facing. With the explosively growth of computation power nowadays, computer simulation can play an increasingly important role in the design of new catalysts, avoiding the costly trail-and-error attempts and facilitating the development cycle. The goal to inverse design of new materials with desired catalytic property was once far off, but now achievable. The major focus of this dissertation is to find the general rules that govern the catalytic performance of a nanoparticle as the function of its structure. Three types of multi-metallic nanoparticles have been investigated in this dissertation, core-shell, random alloy and alloy-core@shell. Significant structural rearrangement was found on [email protected] and [email protected] nanoparticle, which is responsible for a dramatic improvement in catalytic performance. Nonlin- ear binding trends were found and modeled for random alloy nanoparticles, providing a prescription for tuning catalytic activity through alloying. Studies of ORR on Pd/Au random alloy NP and hydrogenation reaction on Rh/Ag random alloy NP revealed that binding on individual ensemble should be in- vestigated when large disparity of adsorbate affinity is presented between two alloying elements. In the alloy-core@shell system, I demostrated a general linear correlations between the adsorbate binding energy to the shell of an alloy-core@shell nanoparticle and the composition of the core. This relation- ship allows for interpolation of the properties of single-core@shell particles and an approach for tuning the catalytic activity of the particle. A series of promising catalysts were then predicted for ORR, HER and CO oxidation. As a first attempt to bridge the material gap, bimetallic nano clus- ter supported on CeO₂(111) was investigated for CO oxidation. A strong support-metal interaction induces a preferential segregation of the more reac- tive element to the NC-CeO₂ perimeter, generating an interface with the Au component. (Au-Cu)/CeO₂ was found to be optimal for catalyzing CO oxida- tion via a bifunctional mechanism. O₂ preferentially binds to the Cu-rich sites whereas CO binds to the Au-rich sites. A method called distributed replica dynamics (DRD) is proposed at last to utilize enormous distributed computing resources for molecular dynamics simulations of rare-event in chemical reac- tions. High efficiency can be achieved with an appropriate choice of N [subscript rep] and t [subscript rep] for long-time MD simulation. Advisors/Committee Members: Henkelman, Graeme (advisor).

Subjects/Keywords: Nanoparticles; Catalysis; Alloy; Core-shell; DFT; ORR; Structure-function correlation; Metal-support interaction; Accelerated molecular dynamics

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APA (6^th Edition):

Zhang, Liang, 1. (2014). Theoretical study of correlation between structure and function for nanoparticle catalysts. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/28338

Chicago Manual of Style (16^th Edition):

Zhang, Liang, 1986. “Theoretical study of correlation between structure and function for nanoparticle catalysts.” 2014. Doctoral Dissertation, University of Texas – Austin. Accessed January 27, 2021. http://hdl.handle.net/2152/28338.

MLA Handbook (7^th Edition):

Zhang, Liang, 1986. “Theoretical study of correlation between structure and function for nanoparticle catalysts.” 2014. Web. 27 Jan 2021.

Vancouver:

Zhang, Liang 1. Theoretical study of correlation between structure and function for nanoparticle catalysts. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2014. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/2152/28338.

Council of Science Editors:

Zhang, Liang 1. Theoretical study of correlation between structure and function for nanoparticle catalysts. [Doctoral Dissertation]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/28338

Delft University of Technology

23. Ho, Lim Chi (author). Minimization of drainage time of filled PET bottle with initial rotation: A numerical study.

Degree: 2020, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:ea1e3c18-8844-42ed-81e2-b7fcef59d100

► The drainage time of liquid-filled PET bottles can be greatly reduced by pre-rotating the bottle with a certain angular velocity. Depending on the magnitude of… (more)

▼ The drainage time of liquid-filled PET bottles can be greatly reduced by pre-rotating the bottle with a certain angular velocity. Depending on the magnitude of the angular velocity, up to four different flow regimes can be distinguished during the emptying of a bottle: bubble regime, transition regime, vortex regime and the swirl regime. At zero or low pre-rotation, the flow is in the so-called bubble regime in which the intermittent downward liquid flow is accompanied by an upward motion of irregularly shaped air bubbles into the bottle. At sufficiently high pre-rotation, the picture is completely different. After initial transient behaviour in which the flow is first in the bubble regime, the flow undergoes transition towards a so-called vortex regime. This is characterized by regular downward motion of liquid along the bottle wall in a free-surface vortex and accompanying upward motion of air through the nozzle core. Finally, close to the end of the drainage process another transition towards a so-called swirl regime takes place, in which the last bit of liquid swirls around in the bottle before being slowed down sufficiently to exit the bottle through the nozzle opening. Dimensional analysis indicates that for a specific bottle geometry the non-dimensional total drainage time td/td,0, where td,0 is a characteristic drainage time scale for stationary low-viscosity fluids in the bubble regime, depends primarily on 3 non-dimensional numbers: (1) the rotation number, Π (2) the Morton number, Mo, and (3) the E¨otvos number, Eo. The former represents the characteristic ratio of centrifugal to hydrostatic forces inside the liquid phase. The objective of this study is to determine the relationship between the non-dimensional drainage time and Π and gain insight in the influence of E¨otvos and Morton onto this. To this purpose, a parametric CFD study of a model PET bottle has been conducted and the results have been compared with previous preliminary experiments performed in our group. The numerical study is divided into three categories, each discussing the influence of one of the dimensionless parameters. The influence of the Π-number was studied by altering the initial rotational velocity of the bottle. It was found that at some critical Π-number, the drainage time was minimal. A further increase beyond the critical Π-number resulted in a longer drainage time, due to the stronger centrifugal force acting on the liquid layer. It was found through an analytical solution and verified with the numerical results that the rate at which the Π-number grows in relation to the dimensionless drainage time is to the power 3 for the laminar case and to the power 3/2 for the turbulent case. Below the critical value, the flow is expected to remain in the so-called bubble regime, also increasing the drainage time. Furthermore, the onset of the vortex regime was expected to occur at a constant value of Π. This was also verified with the numerical results and a strong correlation was found between the onset and the corresponding… Advisors/Committee Members: Breugem, W.P. (mentor), Pourquie, M.J.B.M. (mentor), Delfos, R. (graduation committee), Delft University of Technology (degree granting institution).

Subjects/Keywords: Air-core vortex; Bubble regime; Mutli-phase numerical study; PET bottle; Computational Fluid Dynamics; Siwrling flow

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APA (6^th Edition):

Ho, L. C. (. (2020). Minimization of drainage time of filled PET bottle with initial rotation: A numerical study. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:ea1e3c18-8844-42ed-81e2-b7fcef59d100

Chicago Manual of Style (16^th Edition):

Ho, Lim Chi (author). “Minimization of drainage time of filled PET bottle with initial rotation: A numerical study.” 2020. Masters Thesis, Delft University of Technology. Accessed January 27, 2021. http://resolver.tudelft.nl/uuid:ea1e3c18-8844-42ed-81e2-b7fcef59d100.

MLA Handbook (7^th Edition):

Ho, Lim Chi (author). “Minimization of drainage time of filled PET bottle with initial rotation: A numerical study.” 2020. Web. 27 Jan 2021.

Vancouver:

Ho LC(. Minimization of drainage time of filled PET bottle with initial rotation: A numerical study. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2021 Jan 27]. Available from: http://resolver.tudelft.nl/uuid:ea1e3c18-8844-42ed-81e2-b7fcef59d100.

Council of Science Editors:

Ho LC(. Minimization of drainage time of filled PET bottle with initial rotation: A numerical study. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:ea1e3c18-8844-42ed-81e2-b7fcef59d100

University of Lund

24. Oghbaie, Shabnam. Dissociation dynamics of highly excited molecules: Theory and Experiment.

Degree: 2017, University of Lund

URL: https://lup.lub.lu.se/record/f5d90cd0-24cc-4e91-9638-145ee6567423 ; https://portal.research.lu.se/ws/files/23811350/Kappa.pdf

► This thesis presents studies on dissociation of two model molecules: Butadiene and Cyclopropane. Tunable synchrotron radiation was used to ionize or excite the molecules in… (more)

▼ This thesis presents studies on dissociation of two model molecules: Butadiene and Cyclopropane. Tunable synchrotron radiation was used to ionize or excite the molecules in the gas phase, and the momentum correlation of the resulting fragment ions were measured using a 3D momenta coincident ion spectroscopy. The experimental results were interpreted with the aid of ab-initio quantum calculation. This allows us to gain insight into the fundamental processes behind the molecular dissociation, that how correlated electronic and nuclear dynamics drive molecular dissociation.Tunable XUV-radiation was used to doubly ionize molecules to different states.By Comparing experimental and theoretical values for appearance energy and kinetic energy released of the dissociation channels, electronic gateway state of each dissociation channels were identified. By analysing the momentum vector of ion pairs as a function of photon energy and internal energy sharing in the dissociative double ionization channels, mechanisms of double ionization (direct or indirect) processes were investigated. The studies shed light on the electron-electron and electron-nuclear correlation effects in the molecules.Tunable X-rays were used to selectively excite a localized core electron to different valence orbitals, and the subsequent autoionization and dissociation processes were studied by analysing the correlated momentum of ionic fragments. In butadiene, the dependence of molecular dissociation on the initial site of core-hole was studied for the chemically shifted terminal and central carbon core-electrons excitation.In cyclopropane the dependence of molecular dissociation on the changing of the molecular bonding character was studied for different core-to-valence excitation.The studies indicated the importance of the ultra-fast nuclear dynamics initiatedwithin a few femtosecond core-hole lifetime changing the picture of electron-electron correlation in autoionization processes and leading to specific dissociation channels.

Subjects/Keywords: Natural Sciences; Molecular dissociation; core-electron excitation; double ionization; femtoseconds molecular dynamics; Isomerization; symmetry breaking; momentum imaging; site-selective dissociation; butadiene; cyclopropane; nuclear dynamics; Auger decay

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APA (6^th Edition):

Oghbaie, S. (2017). Dissociation dynamics of highly excited molecules: Theory and Experiment. (Doctoral Dissertation). University of Lund. Retrieved from https://lup.lub.lu.se/record/f5d90cd0-24cc-4e91-9638-145ee6567423 ; https://portal.research.lu.se/ws/files/23811350/Kappa.pdf

Chicago Manual of Style (16^th Edition):

Oghbaie, Shabnam. “Dissociation dynamics of highly excited molecules: Theory and Experiment.” 2017. Doctoral Dissertation, University of Lund. Accessed January 27, 2021. https://lup.lub.lu.se/record/f5d90cd0-24cc-4e91-9638-145ee6567423 ; https://portal.research.lu.se/ws/files/23811350/Kappa.pdf.

MLA Handbook (7^th Edition):

Oghbaie, Shabnam. “Dissociation dynamics of highly excited molecules: Theory and Experiment.” 2017. Web. 27 Jan 2021.

Vancouver:

Oghbaie S. Dissociation dynamics of highly excited molecules: Theory and Experiment. [Internet] [Doctoral dissertation]. University of Lund; 2017. [cited 2021 Jan 27]. Available from: https://lup.lub.lu.se/record/f5d90cd0-24cc-4e91-9638-145ee6567423 ; https://portal.research.lu.se/ws/files/23811350/Kappa.pdf.

Council of Science Editors:

Oghbaie S. Dissociation dynamics of highly excited molecules: Theory and Experiment. [Doctoral Dissertation]. University of Lund; 2017. Available from: https://lup.lub.lu.se/record/f5d90cd0-24cc-4e91-9638-145ee6567423 ; https://portal.research.lu.se/ws/files/23811350/Kappa.pdf

Brigham Young University

25. Mortensen, Clifton H. A Computational Fluid Dynamics Feature Extraction Method Using Subjective Logic.

Degree: MS, 2010, Brigham Young University

URL: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3207&context=etd

► Computational fluid dynamics simulations are advancing to correctly simulate highly complex fluid flow problems that can require weeks of computation on expensive high performance clusters.… (more)

▼ Computational fluid dynamics simulations are advancing to correctly simulate highly complex fluid flow problems that can require weeks of computation on expensive high performance clusters. These simulations can generate terabytes of data and pose a severe challenge to a researcher analyzing the data. Presented in this document is a general method to extract computational fluid dynamics flow features concurrent with a simulation and as a post-processing step to drastically reduce researcher post-processing time. This general method uses software agents governed by subjective logic to make decisions about extracted features in converging and converged data sets. The software agents are designed to work inside the Concurrent Agent-enabled Feature Extraction concept and operate efficiently on massively parallel high performance computing clusters. Also presented is a specific application of the general feature extraction method to vortex core lines. Each agent's belief tuple is quantified using a pre-defined set of information. The information and functions necessary to set each component in each agent's belief tuple is given along with an explanation of the methods for setting the components. A simulation of a blunt fin is run showing convergence of the horseshoe vortex core to its final spatial location at 60% of the converged solution. Agents correctly select between two vortex core extraction algorithms and correctly identify the expected probabilities of vortex cores as the solution converges. A simulation of a delta wing is run showing coherently extracted primary vortex cores as early as 16% of the converged solution. Agents select primary vortex cores extracted by the Sujudi-Haimes algorithm as the most probable primary cores. These simulations show concurrent feature extraction is possible and that intelligent agents following the general feature extraction method are able to make appropriate decisions about converging and converged features based on pre-defined information.

Subjects/Keywords: Clifton Mortensen; feature extraction; subjective logic; computational fluid dynamics; agent-based data mining; vortex core; massive data set post-processing; Mechanical Engineering

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APA (6^th Edition):

Mortensen, C. H. (2010). A Computational Fluid Dynamics Feature Extraction Method Using Subjective Logic. (Masters Thesis). Brigham Young University. Retrieved from https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3207&context=etd

Chicago Manual of Style (16^th Edition):

Mortensen, Clifton H. “A Computational Fluid Dynamics Feature Extraction Method Using Subjective Logic.” 2010. Masters Thesis, Brigham Young University. Accessed January 27, 2021. https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3207&context=etd.

MLA Handbook (7^th Edition):

Mortensen, Clifton H. “A Computational Fluid Dynamics Feature Extraction Method Using Subjective Logic.” 2010. Web. 27 Jan 2021.

Vancouver:

Mortensen CH. A Computational Fluid Dynamics Feature Extraction Method Using Subjective Logic. [Internet] [Masters thesis]. Brigham Young University; 2010. [cited 2021 Jan 27]. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3207&context=etd.

Council of Science Editors:

Mortensen CH. A Computational Fluid Dynamics Feature Extraction Method Using Subjective Logic. [Masters Thesis]. Brigham Young University; 2010. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3207&context=etd

26. Zmerli, Moustafa. Étude de la dynamique de photodissociation de molécules ionisées en couche interne par spectroscopie de moment : Photodissociation dynamics of ionized molecules in inner-shell by momentum spectroscopy.

Degree: Docteur es, Chimie physique et Chimie analytique, 2019, Sorbonne université

URL: http://www.theses.fr/2019SORUS430

►

Nous avons étudié expérimentalement la relaxation d'un système atomique ou moléculaire après l'ionisation en couche interne par un photon X (2-12 keV). Les différents processus… (more)

▼

Nous avons étudié expérimentalement la relaxation d'un système atomique ou moléculaire après l'ionisation en couche interne par un photon X (2-12 keV). Les différents processus de désexcitation ont été étudiés par la mesure en coïncidence du vecteur vitesse des électrons et des ions émis permettant d'avoir accès aux corrélations vectorielles entre l’émission électronique et les ions formés. Des nouveaux résultats expérimentaux sur l’argon combinés avec le modèle théorique développé par nos collaborateurs ont montré l'existence effective du transfert de moment angulaire dû au PCI entre le photoélectron et l’électron Auger. Ensuite, la dynamique de fragmentations à trois corps de CS2 a été interprétée à l’aide d’une combinaison des observables géométriques et cinématiques. Nous avons montré qu’il est possible de séparer les différents types de fragmentation dans le cas où il s’agit d’une voie mixte. Puis, nous avons montré la présence des voies concertées massives après la dissociation de CH3I. Nous avons également observé la formation des ions multiplement chargés où la charge totale induite est arrivée jusqu’à +15 par l’absorption d’un photon unique. Enfin, la comparaison des données expérimentales avec des simulations de modèle d’explosion coulombienne nous a permis d’estimer le déplacement moyen de la molécule durant la relaxation.

We experimentally studied the relaxation of atomic and molecular systems following core-shell photoionization in tender X-ray regime (2-12 keV). The various processes of de-excitation have been studied by the coincidence measurements of the velocity vector of emitted electrons and ions allowing access to the vector correlations between the electrons and ions. New experimental results on argon combined with theoretical model developed by our collaborators have shown the effective existence of angular momentum transfer due to the Post-collision interaction (PCI) between the photoelectron and the Auger electron. Then, the CS2 three-body fragmentation dynamics was interpreted using a combination of geometric and kinematic observables. We have shown that it is possible to separate the different types of fragmentation in case of the mixed pathway. We also showed the presence of massive concerted pathways after the dissociation of CH3I molecule. Moreover, we have observed the formation of multiply charged ions where the total charge induced has reached +15 by single photon absorption. Finally, the comparison of experimental data with Coulomb explosion model allowed us to estimate the average displacement of the molecule during relaxation.

Advisors/Committee Members: Simon, Marc (thesis director), Guillemin, Renaud (thesis director).

Subjects/Keywords: Coïncidence; Spectroscopie de moment; COLTRIMS; PEPIPIPICO; Dynamique de fragmentation; Photodissociation; Distribution angulaire; Explosion coulombienne; Momentum spectroscopy; Dissociation dynamics; Core-shell photoionization; 543.54; 541.3

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APA (6^th Edition):

Zmerli, M. (2019). Étude de la dynamique de photodissociation de molécules ionisées en couche interne par spectroscopie de moment : Photodissociation dynamics of ionized molecules in inner-shell by momentum spectroscopy. (Doctoral Dissertation). Sorbonne université. Retrieved from http://www.theses.fr/2019SORUS430

Chicago Manual of Style (16^th Edition):

Zmerli, Moustafa. “Étude de la dynamique de photodissociation de molécules ionisées en couche interne par spectroscopie de moment : Photodissociation dynamics of ionized molecules in inner-shell by momentum spectroscopy.” 2019. Doctoral Dissertation, Sorbonne université. Accessed January 27, 2021. http://www.theses.fr/2019SORUS430.

MLA Handbook (7^th Edition):

Zmerli, Moustafa. “Étude de la dynamique de photodissociation de molécules ionisées en couche interne par spectroscopie de moment : Photodissociation dynamics of ionized molecules in inner-shell by momentum spectroscopy.” 2019. Web. 27 Jan 2021.

Vancouver:

Zmerli M. Étude de la dynamique de photodissociation de molécules ionisées en couche interne par spectroscopie de moment : Photodissociation dynamics of ionized molecules in inner-shell by momentum spectroscopy. [Internet] [Doctoral dissertation]. Sorbonne université; 2019. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2019SORUS430.

Council of Science Editors:

Zmerli M. Étude de la dynamique de photodissociation de molécules ionisées en couche interne par spectroscopie de moment : Photodissociation dynamics of ionized molecules in inner-shell by momentum spectroscopy. [Doctoral Dissertation]. Sorbonne université; 2019. Available from: http://www.theses.fr/2019SORUS430

KTH

27. Hansell, Markus. Dynamic analyses of hollow core slabs : Experimental and numerical analyses of an existing floor.

Degree: Structural Engineering and Bridges, 2020, KTH

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278539

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For intermediate floors in residential and office buildings, as well as in parking garages and malls, there is a wide use of hollow core… (more)

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For intermediate floors in residential and office buildings, as well as in parking garages and malls, there is a wide use of hollow core concrete slabs in Sweden today. Hollow core slabs are precast and prestressed concrete elements with cylindrical-shaped voids extending along the length of the slab. These structural elements have the advantage compared to cast-in-situ concrete slabs that they have a high strength, due to the prestressing, and that the voids allow for a lower self-weight. Additionally, the voids allow for a reduction in the use of concrete material. These characteristics offer possibilities to build long-span floors with slender designs. However, a consequence of the slenderness of the slabs is that such floors have an increased sensitivity to vibrations induced by various dynamic loads. In residential and office buildings vibrations are primarily caused by human activity, and therefore concerns related to the serviceability of such floors are raised. These vibrations are often not related to problems with structural integrity, but rather to different aspects of comfort of the residents or workers. The aim of this thesis is to provide additional information regarding the dynamic behavior of hollow core floors. An experimental modal analysis has been performed on an existing floor in an office building. The dynamic properties in the form of natural frequencies, mode shapes, damping ratios and frequency response functions were derived and analyzed from these measurements. Subsequently, several finite element models were developed, aiming to reproduce the experimental dynamic behavior of the studied floor. The measurements initially showed some unexpected dynamic responses of the floor. For this reason, more advanced methods of signal analyses were applied to the data. The analyses showed that the slab has some closely spaced modes and that the modes of the floor are complex to a certain degree. The finite element models were studied with different configurations. In particular, the effect the model size, boundary conditions, material properties and potential structural discontinuities have on the dynamic response of the slab was studied. Sufficiently good agreement has been achieved between the experimental and numerical results in terms of natural frequencies and mode shapes. The acceleration amplitude responses of the numerical models were generally higher than the ones obtained from the measurements, which leads to difficulties in matching of the frequency response functions.

Håldäck i betong används idag i stor utsträckning som bjälklag i bostads- och kontorsbyggnader, liksom i parkeringsgarage och köpcentra. Håldäcksbjälklag består av prefabricerade och förspända betongelement, med cylindriska hål som sträcker sig i plattans längsriktning. Dessa konstruktionselement har fördelen, jämfört med platsgjutna betongplattor, att de har en hög hållfasthet på grund av förspänningen och att hålen möjliggör en lägre egenvikt. Dessutom gör hålen att en mindre mängd betongmaterial behövs. Dessa…

Subjects/Keywords: Hollow core slab; Structural dynamics; Signal analysis; Mode shape; Frequency response function; Complex mode; FE-model; Håldäcksbjälklag; Strukturdynamik; Signalanalys; Modform; Frekvenssvar; Komplex mod; FE-modellering.; Building Technologies; Husbyggnad

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APA (6^th Edition):

Hansell, M. (2020). Dynamic analyses of hollow core slabs : Experimental and numerical analyses of an existing floor. (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278539

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Hansell, Markus. “Dynamic analyses of hollow core slabs : Experimental and numerical analyses of an existing floor.” 2020. Thesis, KTH. Accessed January 27, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278539.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Hansell, Markus. “Dynamic analyses of hollow core slabs : Experimental and numerical analyses of an existing floor.” 2020. Web. 27 Jan 2021.

Vancouver:

Hansell M. Dynamic analyses of hollow core slabs : Experimental and numerical analyses of an existing floor. [Internet] [Thesis]. KTH; 2020. [cited 2021 Jan 27]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278539.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hansell M. Dynamic analyses of hollow core slabs : Experimental and numerical analyses of an existing floor. [Thesis]. KTH; 2020. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278539

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

28. Guénolé, Julien. Étude par simulations à l'échelle atomique de la déformation de nanofils de silicium : Atomistic simulation study of the deformation of silicon nanowires.

Degree: Docteur es, Milieux denses, matériaux et composants, 2012, Poitiers

URL: http://www.theses.fr/2012POIT2321

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L'étude des nano-objets en matériau semi-conducteur a révélé des propriétés mécaniques exceptionnelles, différentes de celles observées dans le massif. Outre l'intérêt technologique majeur qu'ils représentent… (more)

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L'étude des nano-objets en matériau semi-conducteur a révélé des propriétés mécaniques exceptionnelles, différentes de celles observées dans le massif. Outre l'intérêt technologique majeur qu'ils représentent à travers la miniaturisation toujours plus poussée des systèmes électroniques, leurs caractéristiques intrinsèques en font des objets particulièrement bien adaptés pour des études fondamentales. Dans ce contexte, nous avons étudié le déclenchement de la plasticité dans les nano-fils de silicium, les premiers stades de la plasticité étant en effet déterminants pour l'évolution ultérieure du système. Le silicium est ici considéré comme un semi-conducteur modèle. Pour cette étude, nous avons utilisé des simulations atomistiques qui sont parfaitement appropriées à l'analyse détaillée de la structure atomique des nano-objets. Après avoir contextualisé notre étude tant du point de vue de l'expérience que de celui des simulations, nous présentons les techniques numériques que nous avons utilisées. Nous décrivons ensuite l'étude de la déformation de nano-fils monocristallins, révélant notamment le rôle majeur des surfaces et l'activation d'un système de glissement jamais observé dans le silicium massif. Ce système de glissement est analysé en détail, et son activation est expliquée notamment au moyen de calculs ab initio. Enfin, nous avons considéré la déformation de nano-fils coeur-coquille cristal-amorphe et mis en évidence un comportement différent de celui observé pour les nano-fils monocristallins. Ainsi, des défauts natifs à l'interface cristal-amorphe semblent agir comme des germes favorisant la nucléation de la première dislocation qui va initier la plasticité.

The study of semiconductor nano-objets has revealed amazing mechanical properties, different from what is commonly observed in bulk. Besides the technological interest of these objects, due to the ever more pronounced miniaturization of electronic devices, their intrinsic specificities make them particularly well suited for fundamental studies. During this thesis, we have thus studied the onset of plasticity in silicon nanowires, the first stages of plasticity being indeed deciding for the subsequent evolution of the system. Silicon is here considered as a model semiconductor. For that study, we have used atomistic simulations, which are well appropriate for the detailed analysis of the nano-objects atomic structure. We first recall the context of that study, both from the experiments and simulations points of view. We then present the numerical methods used. Thestudy of the deformation of monocrystalline nanowires is then described; it reveals in particular the deciding role of surfaces, and the activation of one slip system never observed in bulk silicon. This slip system is analyzed in details, and its activation is explained notably thanks to ab initio calculations. Finally, crystalline-amorphous core-shell silicon nanowires are considered; and shownto exhibit a different behavior from that of monocrystalline nanowires. Indeed, native defects at…

Advisors/Committee Members: Brochard, Sandrine (thesis director), Godet, Julien (thesis director).

Subjects/Keywords: Dislocation; Semi-conducteurs; Silicium; Plasticité; Déformation; Nanofil; Cœur-coquille; Simulation; Dynamique moléculaire; Dislocation; Semiconductors; Silicon; Plasticity; Deformation; Nanowire; Core-shell; Simulation; Molecular dynamics; 620.1

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Guénolé, J. (2012). Étude par simulations à l'échelle atomique de la déformation de nanofils de silicium : Atomistic simulation study of the deformation of silicon nanowires. (Doctoral Dissertation). Poitiers. Retrieved from http://www.theses.fr/2012POIT2321

Chicago Manual of Style (16^th Edition):

Guénolé, Julien. “Étude par simulations à l'échelle atomique de la déformation de nanofils de silicium : Atomistic simulation study of the deformation of silicon nanowires.” 2012. Doctoral Dissertation, Poitiers. Accessed January 27, 2021. http://www.theses.fr/2012POIT2321.

MLA Handbook (7^th Edition):

Guénolé, Julien. “Étude par simulations à l'échelle atomique de la déformation de nanofils de silicium : Atomistic simulation study of the deformation of silicon nanowires.” 2012. Web. 27 Jan 2021.

Vancouver:

Guénolé J. Étude par simulations à l'échelle atomique de la déformation de nanofils de silicium : Atomistic simulation study of the deformation of silicon nanowires. [Internet] [Doctoral dissertation]. Poitiers; 2012. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2012POIT2321.

Council of Science Editors:

Guénolé J. Étude par simulations à l'échelle atomique de la déformation de nanofils de silicium : Atomistic simulation study of the deformation of silicon nanowires. [Doctoral Dissertation]. Poitiers; 2012. Available from: http://www.theses.fr/2012POIT2321

University of Lund

29. Qenawy, Mohamed. Ultrafast Photoinduced Processes in Core and Core–Shell Quantum Dots for Solar Cell Applications “Tiny Crystals for Big Applications”.

Degree: 2015, University of Lund

URL: https://lup.lub.lu.se/record/5051679 ; https://portal.research.lu.se/ws/files/5516980/5051929.pdf

► The balance between our demands of energy and the energy we are consuming is not in equilibrium anymore. Therefore, the search for other energy resources… (more)

▼ The balance between our demands of energy and the energy we are consuming is not in equilibrium anymore. Therefore, the search for other energy resources is indispensable. Sustainable energy sources offer the alternative to the fossil fuels. Within many types of sustainable energy sources, solar energy offers more than the total global energy consumption. Solar cells are the smart conversion tools to harvest the incident photons and create electricity out of these photons. Solar cells have passed through different generations where two important factors control the solar cells market. The solar cell efficiency and price play the cornerstones in the solar cell marketing. Third generation of solar cells aims to maximize the price–performance equation by using cheap materials without compromising efficiency. Nanomaterials have emerged as the promising building blocks to harvest the solar light in the third generation of the solar cells. Among them, quantum dots (QDs) can be used as viable candidate due to their superb features such as high extinction coefficient, a tunable absorption edge, and the possibility to generate and collect multiple excitons by using single, high energy photon. Both the behaviors of photoexcited electrons and holes determine the overall efficiency of QD based solar cells. This thesis presents a systematic study of the ultrafast photoinduced charge dynamics in QD solar cell materials including the charge transfer, exciton migration, carrier trapping and their influence on real solar cell performance. The materials investigated start with conventional neat core CdSe QDs and extend to gradient Cd1-xSe1-yZnxSy core–shell (CS) QDs. The latter are used to obtain improved optical and device performance. The electron injection from CdSe into ZnO nanowires were first observed to be very fast (few ps). This fast electron injection encourages us to study the possibility to inject multiple electrons from a QD under high excitation conditions. We revealed that a competition between electron injection and Auger recombination occurs. Compared with electrons, the photoinduced holes are more likely to be trapped. However, such trap states sometimes can be radiative with long lifetime up to tens of microseconds in oleic acid capped CdSe QDs. In this scenario, the hole injection in p-type QD solar cells are proved to be less efficient (<10%) compared with electron injection in n-type counterparts. It is highly affected by the surface trapping sites induced by the linker exchange process. The hole injection can then be improved by passivating the surface trap sites using core shell structures. Besides electron or hole injection, exciton migration can also occur via Förster resonant energy transfer (FRET). We found that FRET between QDs would enable to make use of the absorption of light by the indirectly attached QDs in QD-sensitized metal oxide (MO) anodes. In well-organized multi-sized QD mixtures, the energy transfer is even more pronounced. We experimentally observed the FRET process in randomly arranged…

Subjects/Keywords: Atom and Molecular Physics and Optics; Quantum dots; core–shell; electron injection; hole injection; hole trapping; exciton migration; solar cells; ultrafast dynamics; time-resolved spectroscopy.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Qenawy, M. (2015). Ultrafast Photoinduced Processes in Core and Core–Shell Quantum Dots for Solar Cell Applications “Tiny Crystals for Big Applications”. (Doctoral Dissertation). University of Lund. Retrieved from https://lup.lub.lu.se/record/5051679 ; https://portal.research.lu.se/ws/files/5516980/5051929.pdf

Chicago Manual of Style (16^th Edition):

Qenawy, Mohamed. “Ultrafast Photoinduced Processes in Core and Core–Shell Quantum Dots for Solar Cell Applications “Tiny Crystals for Big Applications”.” 2015. Doctoral Dissertation, University of Lund. Accessed January 27, 2021. https://lup.lub.lu.se/record/5051679 ; https://portal.research.lu.se/ws/files/5516980/5051929.pdf.

MLA Handbook (7^th Edition):

Qenawy, Mohamed. “Ultrafast Photoinduced Processes in Core and Core–Shell Quantum Dots for Solar Cell Applications “Tiny Crystals for Big Applications”.” 2015. Web. 27 Jan 2021.

Vancouver:

Qenawy M. Ultrafast Photoinduced Processes in Core and Core–Shell Quantum Dots for Solar Cell Applications “Tiny Crystals for Big Applications”. [Internet] [Doctoral dissertation]. University of Lund; 2015. [cited 2021 Jan 27]. Available from: https://lup.lub.lu.se/record/5051679 ; https://portal.research.lu.se/ws/files/5516980/5051929.pdf.

Council of Science Editors:

Qenawy M. Ultrafast Photoinduced Processes in Core and Core–Shell Quantum Dots for Solar Cell Applications “Tiny Crystals for Big Applications”. [Doctoral Dissertation]. University of Lund; 2015. Available from: https://lup.lub.lu.se/record/5051679 ; https://portal.research.lu.se/ws/files/5516980/5051929.pdf

30. Guillotte, Maxime. Étude des propriétés mécaniques de l'or sous forme de nanofil et de structure nanoporeuse par dynamique moléculaire : Study of the mechanical properties of gold in the form of nanowire and nanoporous structure by molecular dynamics.

Degree: Docteur es, Milieux denses, matériaux et composants, 2019, Poitiers

URL: http://www.theses.fr/2019POIT2294

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Dans cette thèse nous avons étudié en détail les propriétés mécaniques de l’or sous forme de nanofils et de structures nanoporeuses revêtues ou non de… (more)

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Dans cette thèse nous avons étudié en détail les propriétés mécaniques de l’or sous forme de nanofils et de structures nanoporeuses revêtues ou non de silicium amorphe (a-Si). Ces travaux ont été effectués par dynamique moléculaire. Nous avons dans un premier temps étudié la déformation cyclique de nanofils d’or (NF-Au) et de nanofils cœur-coquille or-silicium amorphe (NF-AuSi). Ces simulations ont montré que le NF-Au est déformé au cours des cycles par deux mécanismes prépondérants : le maclage extensif puis le glissement d’un unique plan atomique. Le cyclage a pour effet d’altérer progressivement la morphologie de la structure en augmentant le nombre et la taille des défauts créés en surface. La déformation cyclique du NF-AuSi montre que le revêtement de a-Si délocalise la plasticité le long de la structure et permet de mieux conserver la morphologie initiale du cœur. Nous avons ensuite développé une méthode originale de génération de l’or nanoporeux. Cette méthode a été validée par la comparaison structurale et mécanique avec des résultats expérimentaux. Puis nous avons étudié la déformation en traction et en compression de différentes structures générées par cette méthode. Nous avons dans les deux cas mis en évidence les mécanismes de déformation des ligaments. En traction, nous avons apporté de nouveaux résultats permettant de mieux comprendre pourquoi l’or nanoporeux est fragile alors que l’or massif est ductile. En particulier, nous avons étudié comment s’opère la fracture en cascade des ligaments par transfert de contrainte entre ceux-ci. En compression nous avons entre autres montré que l’effondrement des pores et la création de joints de grains est responsable de l’augmentation de la contrainte à la transition écoulement-densification. Les simulations de traction et de compression des mêmes structures mais revêtues de silicium amorphe montrent plusieurs résultats intéressants. Par exemple, la résistance des structures est augmentée d’un facteur 2 à 4. De plus, le revêtement a pour effet de délocaliser la plasticité ce qui augmente la ductilité notamment en traction. En compression, la transition écoulement-densification est avancée probablement en raison de la diminution de la taille des pores causée par le revêtement.

In this thesis we have studied in detail the mechanical properties of gold nanowires and nanoporous gold with and without an amorphous silicon coating (a-Si). This work was done using molecular dynamics simulation. We first studied the cyclic deformation of gold nanowires (Au-NW) and gold-silicon core-shell nanowires (AuSi-NW). These simulations showed that the Au-NW is deformed during cyclic loading by two main mechanisms: extensive twinning and the slip of a single atomic plane. Cycling gradually alters the morphology of the structure by increasing the number and size of defects created on the surface. The cyclic deformation of the AuSi-NW shows that the a-Si coating delocalizes the plasticity along the structure and allows to better preserve the initial morphology of the core. We then…

Advisors/Committee Members: Pizzagalli, Laurent (thesis director), Godet, Julien (thesis director).

Subjects/Keywords: Dynamique moléculaire; Or nanoporeux; Nanofils d'or; Silicium amorphe; Propriétés mécaniques; Nanostructures coeur-Coquille; Molecular dynamics; Nanoporous gold; Gold nanowires; Amorphous silicon; Mechanical properties; Core-Shell nanostructures; 620.1

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Guillotte, M. (2019). Étude des propriétés mécaniques de l'or sous forme de nanofil et de structure nanoporeuse par dynamique moléculaire : Study of the mechanical properties of gold in the form of nanowire and nanoporous structure by molecular dynamics. (Doctoral Dissertation). Poitiers. Retrieved from http://www.theses.fr/2019POIT2294

Chicago Manual of Style (16^th Edition):

Guillotte, Maxime. “Étude des propriétés mécaniques de l'or sous forme de nanofil et de structure nanoporeuse par dynamique moléculaire : Study of the mechanical properties of gold in the form of nanowire and nanoporous structure by molecular dynamics.” 2019. Doctoral Dissertation, Poitiers. Accessed January 27, 2021. http://www.theses.fr/2019POIT2294.

MLA Handbook (7^th Edition):

Guillotte, Maxime. “Étude des propriétés mécaniques de l'or sous forme de nanofil et de structure nanoporeuse par dynamique moléculaire : Study of the mechanical properties of gold in the form of nanowire and nanoporous structure by molecular dynamics.” 2019. Web. 27 Jan 2021.

Vancouver:

Guillotte M. Étude des propriétés mécaniques de l'or sous forme de nanofil et de structure nanoporeuse par dynamique moléculaire : Study of the mechanical properties of gold in the form of nanowire and nanoporous structure by molecular dynamics. [Internet] [Doctoral dissertation]. Poitiers; 2019. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2019POIT2294.

Council of Science Editors:

Guillotte M. Étude des propriétés mécaniques de l'or sous forme de nanofil et de structure nanoporeuse par dynamique moléculaire : Study of the mechanical properties of gold in the form of nanowire and nanoporous structure by molecular dynamics. [Doctoral Dissertation]. Poitiers; 2019. Available from: http://www.theses.fr/2019POIT2294

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Open Access Theses and Dissertations