Multiscale Modeling And Simulations Of Defect Clusters In Crystalline Silicon, 2010 University of Pennsylvania
Multiscale Modeling And Simulations Of Defect Clusters In Crystalline Silicon, Sumeet S. Kapur
Publicly Accessible Penn Dissertations
As the device dimension in semiconductor silicon transistors reach sub-20nm, it significantly enhances the tolerance limits on the size and concentration of defects in the underlying crystalline silicon wafer. Understanding the evolution of defect clusters is critical for controlling the defect density and size distribution within crystalline silicon. The objective of this thesis is to develop the computational methodology that quantitatively describes the evolution of defect clusters in crystalline solids at an atomistic level, and provide a mechanistic understanding of underlying physics behind the defect aggregation process.
In first part of the thesis we develop a novel computational method for ...
Simulation Of A Tubular Solid Oxide Fuel Cell Stack Operating On Biomass Syngas Using Aspen Plus, 2010 Technological University Dublin
Simulation Of A Tubular Solid Oxide Fuel Cell Stack Operating On Biomass Syngas Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy
A tubular solid oxide fuel cell (SOFC) stack was modelled and its operation on biomass syn-gas was investigated. The objective of this work was to develop a computer simulation model of a biomass gasification-SOFC (BG-SOFC) system capable of predicting performance under various operating conditions and using diverse fuels. The stack was modelled using Aspen Plus and considers ohmic, activation and concentration losses. It was validated against published data for operation on natural gas. Operating parameters such as fuel and air utilisation factor Uf and Ua, current density j and steam to carbon ratio STCR were varied and found ...
Conference Proceedings 3rd International Scientific Conference On “Energy Systems With It” At Alvsjö Fair In Association With Energitinget March 16-17 2010, Dr. Erik Dahlquist, Dr. Jenny Palm
Dr. Erik Dahlquist
2010 “The Energiting” is performed for the 12th time. The International Scientific conference is arranged for the 3rd time. The organisers are Swedish Energy Agency, Mälardalen University and the Research School for Energy Systems with LiU, KTH, UU and CTH. The first topic will be “Energy systems” covering use of renewable energy sources, energy conversion and process efficiency improvement with new technologies, as well as societal aspects of the introduction of new technologies. The second topic is “Energy and IT”. This covers energy and load management, interaction between production, distribution and “consumption”, usage of data for decision support and control ...
Hydrodynamic Considerations In An External Loop Airlift Reactor With A Modified Downcomer, 2010 Iowa State University
Hydrodynamic Considerations In An External Loop Airlift Reactor With A Modified Downcomer, Samuel T. Jones, Theodore J. Heindel
Mechanical Engineering Publications
Gas holdup and superficial liquid velocity in the downcomer and riser are studied for an external loop airlift reactor with a downcomer-to-riser area ratio of 1:16. Two downcomer configurations are investigated over a range of superficial gas velocities (0.5 ≤ UG ≤ 20 cm/s) using three aeration plate open area ratios (A = 0.62, 0.99, and 2.22%). These results are compared to a bubble column operated with similar operating conditions. Gas holdup in both the riser and downcomer are found to increase with increasing superficial gas velocity. Results show that riser gas holdup varies slightly with ...
Evaluation Of Stochastic Global Optimization Methods For Modeling Vapor-Liquid Equilibrium Data, 2010 National University of singapore
Evaluation Of Stochastic Global Optimization Methods For Modeling Vapor-Liquid Equilibrium Data, Adrian Bonilla-Petriciolet, Gade Pandu Rangaiah, Juan Gabriel Segovia-Hernández
Parameter estimation for vapor–liquid equilibrium (VLE) data modeling plays an important role in design, optimization and control of separation units. This optimization problem is very challenging due to the high non-linearity of thermodynamic models. Recently, several stochastic optimization methods such as Differential Evolution with Tabu List (DETL) and Particle Swarm Optimization (PSO) have evolved as alternative and reliable strategies for solving global optimization problems including parameter estimation in thermodynamic models. However, these methods have not been applied and compared with respect to other stochastic strategies such as Simulated Annealing (SA), Differential Evolution (DE) and Genetic Algorithm (GA) in the ...
A Comparative Study Of Particle Swarm Optimization And Its Variants For Phase Stability And Equilibrium Calculations In Multicomponent Reactive And Non-Reactive Systems, 2010 Universidad de Guanajuato
A Comparative Study Of Particle Swarm Optimization And Its Variants For Phase Stability And Equilibrium Calculations In Multicomponent Reactive And Non-Reactive Systems, Adrian Bonilla-Petriciolet, Juan Gabriel Segovia-Hernández
Particle swarm optimization is a novel evolutionary stochastic global optimization method that has gained popularity in the chemical engineering community. This optimization strategy has been successfully used for several applications including thermodynamic calculations. To the best of our knowledge, the performance of PSO in phase stability and equilibrium calculations for both multicomponent reactive and non-reactive mixtures has not yet been reported. This study introduces the application of particle swarm optimization and several of its variants for solving phase stability and equilibrium problems in multicomponent systems with or without chemical equilibrium. The reliability and efficiency of a number of particle swarm ...
Harmony Search For Parameter Estimation In Vapor-Liquid Equilibrium Modeling, 2010 Universidad de Guanajuato
Harmony Search For Parameter Estimation In Vapor-Liquid Equilibrium Modeling, Adrian Bonilla-Petriciolet, Juan Gabriel Segovia-Hernandez, Juan Jose Soto-Bernal
This study introduces the application of Harmony Search (HS) method for solving the parameter estimation problem in vapor-liquid equilibrium data modeling. The performance of this novel stochastic optimization strategy has been tested using several sets of binary vapor-liquid equilibrium data with local composition models and the classical approach of least squares. Our results indicate that HS is a promising meta-heuristic for solving global optimization problems in the modeling of phase equilibrium and may offer a better performance than those obtained using current stochastic methods such as the Simulated Annealing or the Particle Swarm Optimization.
Control Properties Of Thermally Coupled Extractive Distillation Sequences, 2010 Universidad de Guanajuato
Control Properties Of Thermally Coupled Extractive Distillation Sequences, Jose De Jesus Ibarra-Sánchez, Juan Gabriel Segovia-Hernandez, Salvador Hernandez, Hector Hernandez-Escoto, Adrian Bonilla-Petriciolet
The structure of the thermally coupled distillation systems offers some control challenges arising from the transfer of vapor (or liquid) streams between the columns. In particular, the presence of recycle streams for coupled schemes has influenced the notion that control problems might be expected during the operation of those systems with respect to the rather well-known behavior of conventional distillation sequences. In this work, we analyze the control properties of thermally coupled extractive distillation schemes. The control properties are analyzed with the application of the singular value decomposition technique and a closed-loop analysis. The results showed that the energy savings ...
Optimization Of An Extractive Dividing Wall Column Using Genetic Algorithms, 2010 Universidad de Guanajuato
Optimization Of An Extractive Dividing Wall Column Using Genetic Algorithms, Cristofer Bravo-Bravo, Juan Gabriel Segovia-Hernandez, Salvador Hernandez, Claudia Gutierrez-Antonio, Adrian Bonilla-Petriciolet, Abel Briones-Ramirez
This work proposes an extractive dividing wall distillation column, optimal designs for which are obtained through a constrained stochastic multiobjective optimization technique. The stochastic procedure allows manipulate 15 variables simultaneously; six are continuous and the rest of them are integer. All resulting optimal designs are rigorous, since the optimization procedure is coupled to Aspen PlusTM. Several case studies are used to show the feasibility of performing extractive separations in dividing wall distillation columns. The numerical performance shows that this method appears to be robust and suitable in the design of intensified distillation systems (with dividing wall).
Prediction Of Steady State Input Multiplicities For The Reactive Flash Separation Using Reaction-Invariant Composition Variables, 2010 Universidad de Guanajuato
Prediction Of Steady State Input Multiplicities For The Reactive Flash Separation Using Reaction-Invariant Composition Variables, Jose Enrique Jaime-Leal, Adrian Bonilla-Petriciolet, Juan Gabriel Segovia-Hernandez, Salvador Hernandez
In this study, we report a new approach for predicting and analyzing steady state input multiplicities in reactive flash separation processes. Necessary conditions are suggested to detect these multiple steady states using reaction-invariant composition variables. Our results suggest that the conditions proposed for identifying the presence of input multiplicities of non-reactive systems are useful for the analysis of reactive systems if transformed composition variables are employed. Performance of our approach is illustrated using MTBE production as case of study.
A Short Method To Calculate Reactive Residue Curve Maps, 2010 Universidad de Guanajuato
A Short Method To Calculate Reactive Residue Curve Maps, Marcelino Carrera-Rodriguez, Juan Gabriel Segovia-Hernandez, Adrian Bonilla-Petriciolet
Reactive residue curve maps (RRCM) are useful for the design of reactive distillation columns as a tool to establish feasible zones of reaction-separation. The calculation of RRCM usually involves great computational effort due to the nonlinearity of the model equations and its iterative nature for the determination of reactive phase equilibrium. In this study, a simplified method for the generation of RRCM is presented. This method is based on the application of reaction-invariant composition variables and assumes that the phase equilibrium constants and the relative volatilities are independent of the temperature. These assumptions allow avoiding iterative calculations for obtaining a ...
Simulation Of A Magnetophoretic Device For The Separation Of Colloidal Particles In Magnetic Fluids, Seif-Eddeen K. Fateen
Seif-Eddeen K Fateen
No abstract provided.
Grafika Inżynierska Ćw., 2010 Wroclaw University of Technology
Grafika Inżynierska Ćw., Wojciech M. Budzianowski
No abstract provided.
Projektowanie Procesów Biotechnologicznych Proj., 2010 Wroclaw University of Technology
Projektowanie Procesów Biotechnologicznych Proj., Wojciech M. Budzianowski
No abstract provided.
Projektowanie I Optymalizacja Procesów Proj., 2010 Wroclaw University of Technology
Projektowanie I Optymalizacja Procesów Proj., Wojciech M. Budzianowski
No abstract provided.
Metody Numeryczne Lab., 2010 Consulting Services
Metody Numeryczne Lab., Wojciech M. Budzianowski
No abstract provided.
Odnawialne Źródła Energii W., 2010 Wroclaw University of Technology
Odnawialne Źródła Energii W., Wojciech M. Budzianowski
No abstract provided.
Molecular Dynamics Simulation Of Poly(Ethylene Terephthalate) Oligomers, 2009 University of Tennessee - Knoxville
Molecular Dynamics Simulation Of Poly(Ethylene Terephthalate) Oligomers, David Keffer, Qifei Wang, Simioan Petrovan, J. Thomas
Molecular dynamics simulations of poly(ethylene terephthalate) (PET) oligomers are performed in the isobaric−isothermal (NpT) ensemble at a state point typical of a finishing reactor. The oligomer size ranges from 1 to 10 repeat units. We report thermodynamic properties (density, potential energy, enthalpy, heat capacity, isothermal compressibility, and thermal expansivity), transport properties (self-diffusivity, zero-shear-rate viscosity, thermal conductivity), and structural properties (pair correlation functions, hydrogen bonding network, chain radius of gyration, chain end-to-end distance) as a function of oligomer size. We compare the results with existing molecular-level theories and experimental data. Scaling exponents as a function of degree of polymerization ...
Molecular Simulations Of H2 Adsorption In Metal-Porphyrin Frameworks (Mpfs): A Potential New Material Evaluation, 2009 University of Tennessee - Knoxville
Molecular Simulations Of H2 Adsorption In Metal-Porphyrin Frameworks (Mpfs): A Potential New Material Evaluation, Ruichang Xiong, David Keffer
Path integral grand canonical Monte Carlo (PI-GCMC) simulations using standard force fields are carried out to calculate the adsorption of H2 in five metal-porphyrin frameworks (MPFs), a new class of metal organic framework (MOF)-type materials. These simulations are performed at 77 K and room temperature (300 K). The adsorption isotherms of H2 in IRMOF-1 and IRMOF-10 are also calculated as a comparison. All calculations indicate that all MPFs adsorbed a higher weight fraction of H2 than both IRMOF-1 and IRMOF-10, with one exception (MPF-2). The gravimetric hydrogen capacities are still well short of practical goals. The MPFs provide additional ...
Molecular Simulation Images, 2009 University of Tennessee - Knoxville
Molecular Simulation Images, David Keffer
These animations and interactive structures are created from various molecular dynamics simulations and quantum calculations. In order to view the interactive structures, you need the free "Chime" Plug-in. In order to view the movie files (in avi format), you will require the following codec: TSCC codec. This work has been supported by DOE BES, AFOSR, NSF and ACS PRF.