1991 — 1994 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Rui: Spectral Methods and Their Combination With the H-P Version of Finite Element Method For Chemically Reacting Flow and Pde's On Nonsmooth Domains @ University of North Carolina At Charlotte
Spectral methods have been widely applied for transient and turbulent flows. However their scope of application has been seriously limited by their inability to treat discontinuous problems and problems on nonsmooth domains. This project intends to reduce these two restrictions of spectral methods. Oscillation-free uniform high order spectral methods to simulate chemically reacting flows, especially the detonation waves and the transition from deflagration to detonation (DDT) will be designed. To ease the domain restrictions, spectral methods and the p- and the h-p version of the finite element methods will be combined. Then the combined method will be applied to general elliptic equations on nonsmooth domains and the results will be used to simulate flows in irregular channels. These methods will be implemented on high performance computers.
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0.954 |
1999 — 2003 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Adaptive Wavelet Element Methods For Highly Parallel Computations @ University of North Carolina At Charlotte
The Adaptive Wavelet element method is a new mathematical method which is fundamentally more appropriate for highly parallel computing than existing methods. This project studies scalable parallel algorithms and simulations based on adaptive wavelet methods for the investigation of combustion flow problems. The project isa driven by the need for large scale simulation capability required by the intrinsic physical property of industrial applications.
The focus of this research is on parallel wavelet simulation of combustion flow problems, which includes the associated algorithmic/mathematical development and software implementation. A new method - the Wavelet Element Method - is introduced based on wavelet and domain decomposition methods. The new method extends the applicability of wavelet methods to combustion problems and other viscous flow problems in more complex geometries and provides a coarse grain parallelism based on domain decomposition. It is efficient, stable, highly accurate, and highly parallel, and it has good data locality. Wavelets support localization in both space and frequency domain which makes adaptive grid generation possible. Wavelet coefficients uniquely indicate the workload variation across subdomains, and parallelism in the wavelet element method comes from two levels - the level of domain decomposition and the level of parallel solution of Spline Wavelet ADI in each subdomain.
Four main tasks will be performed: 1) Develop a two level parallelized wavelet element method, which combines the domain decomposition and wavelet ADI methods, to maximize parallelism, locality, and scalability. 2) Investigate interface conditions among elements (subdomains) in the context of wavelet element and investigate their effects on solution accuracy, workload balance, and communication cost. 3) Study dynamic workload balance based on wavelet coefficients on both domain decomposition level and on ADI wavelet solution in each subdomain. 4) Test the scalable parallel adaptive wavelet element methods on the Deflagration to Detonation Transition Problems for multidimensional premixed flames.
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0.954 |
2000 — 2003 |
Fang, Jiayuan [⬀] Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Development of Efficient and Accurate Numerical Techniques For the Design of Embedded Three Dimensional Rf Components @ University of California-Santa Cruz
This project is on fast and accurate computational techniques for the design of 3D embedded RF components. The numerical method to be investigated is based on a full-wave Mixed Potential Integral Equation formulation that has the capability of providing accurate modeling of 3-D interactions and handling arbitrary multi-layered media with different dielectric constants. Critical mathematical and algorithmic breakthroughs will be explored in the areas of fast calculation of multi-layered dyadic Green's functions over substrate, fast matrix solution of impedance matrices, high order basis functions, and fast frequency sweep techniques. Promising results from our initial investigations indicate that special numerical techniques superior to the techniques used in present software tools can be developed for 3D RF components in multi-layered media, and may lead to significant impact to the design of wireless systems. This project will also provide an opportunity for close interactions among the university team members and National Semiconductor Corporation - the industrial partner. Such an effort will strengthen the graduate education in both engineering and applied mathematics at participating universities, while industry will be benefited by potential fundamental breakthroughs of innovative and exploring research at universities.
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0.954 |
2004 — 2008 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Numerical Methods For Maxwell Equations in Dispersive and Lossy Inhomogeneous Media @ University of North Carolina At Charlotte
This project is to develop accurate and efficient state-of-the art numerical algorithms for electromagnetic scattering in dispersive and lossy inhomogeneous media. Electromagnetic scattering, wave scattering in general, is ubiquitous in scientific and engineering applications. Simulation of wave scattering in dispersive and lossy inhomogeneous media poses two major challenges for fast and accurate computations, namely, the resolution requirement by the large wave number of the problems involved, and the accuracy degeneracy of numerical discretizations due to interfaces of material discontinuities. To address these challenges, the investigator proposed two new approaches: (1) In Time domain: A high order Cartesian grid based Upwinding Embedded Boundary Method for time dependent Maxwell equations in dispersive and lossy inhomogeneous media, and (2) In Frequency Domain: A fast integral method for wave scattering in layered media based on fast calculation algorithms of dyadic Green's functions.
The investigator will apply the numerical algorithms developed under this project for the designing of microscale photonic devices with significant impact on the development of next generation optical technologies for cost efficient home internet broadband access, and also the design of ground penetrating radars, which will contribute to the development of modern detection devices for underground mines and industrial contaminants. Moreover, Research results from this project, in the area of new physics and numerical methods, will be incorporated into the applied mathematics and optics curriculum, potential technology transfer of the results to the area optics industrial will be explored through the existing partnership between the Center and area optics companies. The investigator shall participate actively in the Center's technology training programs with area high schools during the course of this research.
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0.954 |
2005 — 2009 |
Cai, Wei Astratov, Vasily (co-PI) [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
High Order Numerical Methods For Light Propagation in Micro-Photonics @ University of North Carolina At Charlotte
ABSTRACT 0513179 Wei Cai U of NC @ Charlotte
This interdisciplinary proposal is to develop high order numerical methods to provide accurate modeling capabilities of light propagation through microphotonics. The problems of light propagation through such devices are closely related to the design of delay lines, optical buffering devices. Due to small scales of those devices and wave nature of the light signals, the accuracy of the numerical methods, especially the phase accuracy of the numerical methods, is critical in obtaining the speed and phase information of light signals through photonic devices. The development of algorithms for modeling of microphotonics such as resonant waveguides will result in advanced capabilities in solving linear and nonlinear Maxwell equations in inhomogeneous media for a wide range of engineering problems. The potential technology applications of this research will provide integration of optical elements on a single chip, to control velocity of light, to provide routing and switching functionality on a micro-scale by incorporating nonlinear optical material into the microspheres/microcylinders. These are the fundamental questions being addressed in the research communities of modern photonics. The major challenge will be the development of highly accurate and efficient numerical algorithms for the solution of linear and nonlinear Maxwell equations in layered and inhomogeneous media. The following topics will be studied: (a) Discontinuous spectral element methods for time dependent nonlinear Maxwell equations, (b) Upwinding Embedded Boundary Methods, (c) Modeling with the developed algorithms for coupled resonator optical waveguide devices. As a main goal of this proposal, we plan to find solutions to the current bottleneck problems in the designing of coupled resonator waveguides with significant impact on the development of next generation optical technologies. This includes optimization of the nanometric separation between microspheres or microcylinders to achieve a trade-off between reduced group velocity of light (desirable property for optoelectronic applications) and reduced efficiency of optical transport. This also includes understanding of the role of the size disorder existing in the presently available ensembles of microspheres and microcylinders. The results of this proposal will be directly implemented into the manufacturing of photonic devices of coupled microspheres or microcylinders in our laboratory. In addition, publicly available codes will be created for calculating of all types of optical spectra (transmission, reflection and scattering) and photonic band structures of coupled resonator waveguides. One graduate student will conduct research toward a Ph.D. degree in either optics or/and applied mathematics, and his/her participation will contribute to the educational components of the newly established Center of Optoelectronics and Optical Communications at the UNC Charlotte. Research results from this proposal, in the area of new physics and mathematical modeling tools, will be incorporated into the optics curriculum now under development at the Center, potential technology transfer of the results to the area optics industrial will be explored through the existing partnership between the Center and area optics companies. The PIs will also actively participate in the Center's technology training programs with the area high schools.
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0.954 |
2006 — 2012 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Career: Bridging Defect Models and Micro-Deformation Experiments
Career: Bridging Defect Models and Micro-Deformation Experiments
Abstract
The synthesis of new materials and structures at micro and nano scales provides the basis for a wide variety of technological innovations with a profound impact on our way of living. Reliable functioning of new devices based on these materials critically depends on the mechanical stability of the structures under processing and working conditions. The objective of this project is to develop theoretical models and simulation tools that reliably predict the inelastic deformation properties of crystals based on the dynamics of defects. These theoretical models will be tightly coupled with new experimental tools that have been developed to characterize mechanical properties at micro and nano scales. The simulation tools developed in this project will be used to create interactive modules that will strengthen high school and undergraduate curriculum. The modules will demonstrate the atomistic origin of materials properties and integrate existing curriculum on physics, chemistry, mathematics and computer science.
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1 |
2006 — 2009 |
Cai, Wei Melosh, Nicholas [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Experimental and Computational Nanowire Tensile Testing
Abstract (0556032)
We propose to develop an AFM-based nanowire tensile test apparatus together with an experimentally validated computational tool, to obtain fundamental understanding on the mechanical properties of nanowires. The proposal features close integration of theory and experiment to validate and illuminate the results in a manner that would not be possible from a single study alone. This tool set will be essential for a wide array of research and industrial fields with interests in nanowires and nanomaterials, including resonators, composites, nanofluidics, and electrical junctions.
The broader impact of this proposal includes establishing mechanical design guidelines for nanowires and providing a set of computational tools to calculate the behavior of nanowire devices and nanowire/metal interfaces in new applications. These tools will enable a wide range engineers and researchers to confidently implement nanowire designs, a key building block of nanotechnology. The educational plan include the development of a large-scale version of the AFM style tensile test and simplified version of computational codes, demonstrating the concepts of stress, strain, and AFM operation to high school and undergraduate students.
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2007 — 2010 |
Cai, Wei |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Fast and Accurate Numerical Methods of Electrostatic Interactions in Biomolecules @ University of North Carolina Charlotte
[unreadable] DESCRIPTION (provided by applicant): Electrostatic interactions play an essential role in molecular and cellular processes that include signal transmission at synaptic junctions, ion-transport, molecular recognition, and stability and function of DNA, RNA and proteins. Of paramount biological importance is the collective behavior of ions, molecules, and macromolecules having inhomogeneous charge distributions in the aqueous crowded environment of a living cell. Central to this environment is water, which is a complex solvent with non-bulk properties near ions, molecules and water-biopolymer interfaces. The main challenge for modeling electrostatics, as the core calculation of Molecular Dynamics and Monte Carlo simulations, is to balance the accuracy of interactions among charges and the efficiency required for realistic biological systems. For all-atom simulations the Ewald method is currently the most accurate method for large enough system where periodic boundary effects are negligible. Unfortunately, the simulation of a macromolecule requires a large simulation volume, making the Ewald method and similar methods too expensive while a smaller system size compromises accuracy. Meanwhile, modeling the solvent using continuum electrostatics is much faster, but accuracy is compromised by neglecting molecular scale inhomogeneity, such as atomic details near the surface of the solute. [unreadable] [unreadable] [unreadable]
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0.954 |
2007 — 2010 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Collaborative Research: Numerical Computations of Parasitic Parameters With Spectral Stochastic Collocation Methods For Nano-Vlsi Technologies @ University of North Carolina At Charlotte
As the VLSI technology scales down to 45nm feature size and below, the lithography process no longer produces the ideal shape/dimension of circuit components in a silicon wafer. Geometrical parameter variations at 70nm technology can reach as much as 35%, and become increasingly severe as the feature size continues to decrease. The corresponding electrical parameter variations will significantly affect the performance and function of a VLSI circuit. Therefore, computing and analyzing the statistical properties of parasitic parameters in a silicon wafer become inevitable to the emerging nanometer scale VLSI technology. This grant aims to develop stochastic computational methods to address more general stochastic variables with distributions more realistic in nanometer VLSI technology. This project will develop efficient algorithms using sparse grid spectral stochastic collocation method and compute interconnect capacitance and inductance using Wiener-Askey chaos basis and construct proper stochastic computational methods for non-Gaussian random variables. The intellectual merit comes from the development of sophisticated stochastic theories and efficient computing algorithms for the state-of-the-art engineering problems. This research will lay out basic guidelines and ideas and test the methods on realistic engineering problems. The broader impact of the research opens a new research direction in computing parasitic parameters with random process variations. The result of this research will have a great impact on the parasitic parameter extraction, circuit simulation and design of future nanometer scale VLSI circuits. It will lead to practical and efficient algorithms and CAD tools. Research of this project will be integrated into the graduate education of the Ph.D. students in applied mathematics and electrical engineering, and the developed software will be made public.
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0.954 |
2008 — 2010 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Travel Fellowship For Young Researchers to Dislocations 2008 International Conference
Abstract Young Researcher Travel Fellowship for Dislocations 2008 International Conference
Wei Cai, PI
Crystal dislocations are fundamental carriers of plastic deformation in crystalline materials and a good understanding of their behavior forms the scientific basis for improving the ability to manufacture new materials of high mechanical strength. To facilitate information exchange and academic discussions, the ?Dislocations 200X? international conference series was established in 2000 and has since become the major world forum on crystal dislocations taking place every four years on average. The purpose of this project is to establish a Travel Fellowship program to support 12 young outstanding researchers to attend the ?Dislocations 2008? conference to be held in Hong Kong, during October 13-17, 2008.
At the Dislocations 2008 conference, the cutting-edge research on the fundamental mechanisms of plastic deformation will be discussed. The close interaction between experimentalist and theorists, and the organized discussion sessions, are likely to lead to new ideas and scientific breakthroughs. The Travel Fellowship program enabled by this project will attract many young researchers to attend this conference, enabling them to engage in direct communications with the scientists of older generations. Without such a direct inter-generational communication there is a risk that the younger researchers may become disconnected from the wide and rich body of knowledge and experience accumulated by the older generations of dislocation scientists. Underrepresented groups in sciences and engineering, especially women, will be attracted and supported through the selection of speakers and fellowship awardees.
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1 |
2009 — 2013 |
Cai, Wei Mcintyre, Paul (co-PI) [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Catalyzed Nucleation and Growth of Semiconductor Nanowires
Technical. This project addresses locally catalyzed nucleation and growth of semiconductor nanowires (NWs); the approach combines simulation and modeling with in situ and ex situ ex-periments. The closely coupled computational and experimental approach should help to gain fundamental understanding of mechanisms of NW structure evolution and how they can be con-trolled. Atomistic modeling and controlled experiments on NW nucleation and growth kinetics will be carried out so as to provide direct comparisons. The following questions related to metal-catalyzed NW synthesis will be addressed: Q1. What is the mechanism of NW nucleation on dif-ferent substrates and how does it relate to the observed deep sub-eutectic nucleation reported in some catalyst-NW systems? Q2. What mechanisms control normal NW growth and result in growth abnormalities (e.g. kinking)? Q3. What is the mechanism of the termination of NW growth (catalyst nanoparticle solidification)? Using the Si/Ge NW system as a test bed, in situ and ex situ measurements during CVD growth at controlled temperature and pressure conditions will be compared with numerical predictions, validating and guiding the development of compu-tational methods to overcome time scale challenges in the modeling of nucleation events. The latter is a well known major limit to the range of applicability of atomistic simulations to date. The new understanding gained is expected to benefit the broader field of atomistic modeling due to the common occurrence of nucleation events in physical, chemical and biological processes. Non-Technical. The project addresses fundamental research issues in a topical area of elec-tronic/photonic materials science having technological relevance. This basic research, being con-ducted within the context of worldwide efforts among academic and industrial labs to use semi-conductor NWs in new devices, is expected to have strong technological impact. Results ob-tained through this project on NW synthesis may have impact on the development of these and other emerging technologies. The prospect of new science and technology breakthroughs enabled by semiconductor NWs attracts strong interest in such research among undergrads, graduate stu-dents, and faculty. The PIs plan to leverage this 'excitement' and build on it in their education and outreach activities. Specific initiatives will be pursued in: 1) science education outreach to under-represented minorities through a collaboration with a high school science teacher; 2) un-dergraduate experiences in both computational and experimental components of the proposed re-search; and 3) undergraduate and graduate course module development based on research find-ings.
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1 |
2010 — 2014 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Numerical Methods For Wave Propagations in Inhomogeneous Media @ University of North Carolina At Charlotte
In this proposal, the PI will develop numerical methods and their mathematical analysis, ultimately their implementations in studying wave phenomena in nano-electronics, coupled arrays of quantum dots, and phase shift masks in lithography. Propagation of classical electromagnetic and quantum waves plays a key role in these physical and engineering systems. In order to gain a quantitative understanding of the wave phenomena in those systems, accurate and efficient numerical simulations are needed with appropriately designed numerical algorithms. The targeted applications motivate our research with the following three proposed numerical methods: [1] An adaptive conservative cell average spectral method for Wigner equations in electron transport of nano-electronics; [2] A fast integral solver for quantum wave scattering in 3-D quantum dots in layered media [3] A parallel spectral element method based on eigen-oscillations for complex Helmholtz equations. The potential technology impact of this research is to understand the physics involved and provide design guidelines for nano-electronics such as nano-MOSFETs, phase shift masks, and quantum dots.
The numerical methods developed in this research will be used for the engineering design of quantum devices with significant impact on maintaining US technology preeminence in the development of new VLSI microchips, and next generation X-ray lithography in microchip manufacturing. Also, graduate students trained in this project will provide skilled workforce in the competitive high technology job market as well as potential academic researchers.
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0.954 |
2012 — 2016 |
Cai, Wei Mcintyre, Paul (co-PI) [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Structural Transitions During Catalyzed Growth of Semiconductor Nanowires
Technical Description: This computational and experimental research project aims to answer several fundamental questions in the Au-catalyzed vapor-liquid-solid growth of Ge and Si nanowires. In particular, what mechanisms control kinking of nanowires and how does metastable hexagonal-close packed Au form when growth terminates? A three-dimensional continuum phase field model connects atomistic simulations and experimental observations, which use both ex-situ and in-situ characterization methods, and a rapid thermal chemical vapor deposition system. The project also investigates methods of controlling growth to avoid defects and to facilitate synthesis of abrupt doped junctions and axial Si-Ge heterostructures.
Non-technical Description: This project has a broader impact on a wide range of materials research problems in which a close connection between atomistic modeling and experiments is desirable. Results of this project provide lecture materials on atomistic simulations, thermodynamics and kinetic processes in materials synthesis. The project engages undergraduates through summer research. The science education outreach activity introduces San Jose-area high-school students to crystal growth concepts through interactive Android Apps based on a two-dimensional phase field model.
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1 |
2013 — 2015 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
A Parallel Poisson/Helmholtz Solver Using Local Boundary Integral Equation and Random Walk Methods @ University of North Carolina At Charlotte
The objective of this project is to develop a new type of scalable elliptic solvers with high parallel scalability, and a fundamentally new approach in solving Poisson or modified Helmholtz equations in 3-D is proposed. The solution of these equations constitutes a major computational cost for many computational engineer problems such as incompressible flows by projection methods, electrostatic potential problems in molecular biology, and enforcing divergence free constraints of magnetic field in plasma MHD simulations, etc. The approach proposed is based on combining deterministic local boundary integral equation methods and random Brownian walk probabilistic representations of PDE solutions, resulting in straightforward parallel non-iterative solvers for the Dirichlet-to Neumann mappings of the elliptic PDEs, thus the complete solutions of the PDEs with the help of the FMM.
The high performance computers nowadays use many cores in the order of hundreds of thousands designed for parallel implementations. The challenging for algorithms designers is to develop highly scalable and parallel methods to solve the mathematical equations coming from the representations of real world science and engineering problems. The development of the proposed algorithm in this project is a step toward to achieving such a degree of scalability and parallelism for problems, such as flow-structure interactions and electrostatics in computational biology and plasmas. The idea of using both random and deterministic methods in the proposed method is fundamentally different from traditional purely deterministic methods such as multi-grid and domain decomposition methods, and has the potential to produce high impact in the field of scientific and engineering computing at extreme scale.
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0.954 |
2014 — 2015 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Student Travel: 7th International Conference On Multiscale Materials Modeling; Berkeley, California; 6-10 October 2014
This award supports student travel to the 7th International Conference on Multiscale Materials Modeling, October 6 - 10, 2014 in Berkeley, California. Multiscale modeling of materials has emerged as a central theme to address the complexities in the prediction of material behavior. This conference will bring together a range of scientists from around the world and from different sub disciplines to exchange ideas on this topic. The development of multi scale materials for materials is of significance for the goals of the Materials Genome Initiative.
This award provides financial assistance for graduate students and post doctoral researchers to attend the conference by partially supporting their attendance cost. It is expected that about half of such attendees from US institutions will be supported. By providing such financial assistance this award contributes to the goal of broadening the participation in the discipline.
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2016 — 2019 |
Cai, Wei Chen, Duan (co-PI) [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
High Order and Efficient Numerical Methods For Simulating Electromagnetic Phenomena @ University of North Carolina At Charlotte
New materials with special properties are necessary in the search for new clean energy sources and advanced medical devices. Electromagnetic phenomena play a key role in the design of new materials such as meta-materials and conducting materials. Meta-materials, assembled with blocks of meta-atoms of naturally available components, have provided a wide range of new possibilities to design man-made materials with special properties. Novel devices using meta-materials have been proposed including perfect lens and sub-diffraction-limited imaging for medical applications, light harvest in clear energy solar cells. In addition, understanding the conducting flow of a charged system is essential for studying confined nuclear thermal reactions for the exploration of new clean energy sources.
The computational simulation of electromagnetic phenomena is challenging, owing to the demand of highly accurate and efficient numerical methods that not only represent the correct physics in the magnetic induction equation but also resolve the multiple scattering and local field enhancements from random objects in meta-materials. To meet these requirements, the PIs will accomplish the following two tasks in this project: (1) to develop a highly efficient volume integral equation method for Maxwell equations for very accurate computation of multiple scatterings of large number of regular or random objects employed in the construction of meta-materials; (2) to devise a high order constrained transport finite element method for the magnetic induction equations in the magneto-hydrodynamics problem so the global divergence free condition on the magnetic field is preserved. The research findings will be disseminated through journal publications and software tool development.
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0.954 |
2017 — 2020 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Path Integral Monte Carlo Methods For Computing Polarizability Tensors of Nano-Materials and Electrical Impedance Tomography @ Southern Methodist University
This research project aims to develop improved efficient numerical methods for two application areas: highly accurate simulation of the electric and magnetic properties of nanometer-scale materials, and electrical impedance tomography. In both areas, numerical computations with traditional methods are challenging, if not impossible. This project aims to develop novel computational methods based on probabilistic representations of solutions to the partial differential equations under study. Results of the project are expected to have wide applicability, from the development of solar cells to the detection of cancer.
This project concerns the development of highly accurate and efficient numerical methods to simulate the electric and magnetic polarizability tensors of nanoparticles of complex shapes as in nanowires, quantum dots, and DNA, and fast algorithms for electrical impedance tomography (EIT). Due to the geometric complexities of nanoparticles, numerical computations with traditional mesh-based discretization methods such as finite element and boundary element methods face great challenges, if not impossibility. To meet these challenges, in this project, path integral Monte Carlo (PIMC) methods, based on Feynman-Kac probabilistic representations of solutions to partial differential equations, will be studied for material science applications as well as EIT problems. Compared with traditional grid-based numerical methods, the PIMC methods offer the capability of handling objects with highly irregular geometries arising from materials science applications on the one hand, and provide local solutions of partial differential equations over electrodes in forward problems in EIT on the other hand.
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0.954 |
2021 — 2025 |
Cai, Wei |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Collaborative Research: Dmref: Developing Damage Resistant Materials For Hydrogen Storage and Large-Scale Transport
With the promise of a hydrogen economy being closer to reality than it has even been, there is an important need for the design, development, and deployment of appropriate materials that can support and sustain the promise of a hydrogen-based infrastructure. One of the important scientific challenges associated with developing a hydrogen-compatible infrastructure is an understanding of the fundamentals of hydrogen-induced degradation in materials and developing appropriate hydrogen-resistant materials for storage and transport applications. By developing a computationally driven multi-scale modeling platform that will be informed by, and integrated with, experiments, this Designing Materials to Revolutionize and Engineer our Future (DMREF) project aims to accelerate the pace at which the controlling mechanisms of hydrogen embrittlement are discovered. As envisioned by the Materials Genome Initiative (MGI), this project will aim to enable the faster development of hydrogen-resistant materials for the energy transportation sector as it transitions from the transport of fossil fuels to hydrogen-based sources. Beyond the field of hydrogen storage and transport, the fundamental insights obtained from this project could also be helpful in designing fatigue- and corrosion-resistant sub-surface steel structures with longer lifetimes, which could enable materials designs for many other industries as well.
This project aims to advance fundamental knowledge of crack tip processes that control damage accumulation and propagation under fatigue loading and the role of hydrogen in making the material more susceptible to fracture. It is hypothesized that the controlling mechanisms occur in the plastic zone around the crack tip, over a length scale of about 1 to 10 microns, which is too small for continuum theory to be predictive and too large for atomistic simulations to handle by brute force. Such a knowledge gap at the mesoscale will be closed through a tightly coupled experimental-computational program. Computational efforts will build upon the recent advances made in atomistic simulations, dislocation dynamics simulations, with insights on crystal plasticity and continuum-level modeling. The experimental efforts will leverage improved and unique capabilities that include nanoindentation, x-ray tomography (in conjunction with Brookhaven National Laboratory), and in situ testing in hydrogen environments (to be conducted at Sandia National Laboratory). By combining modeling and experiments over multiple length-scales, an experimentally validated multi-scale model for hydrogen effects on fatigue evolution in ferritic steels could be established. Insights obtained from this project have the potential to lead to the development of reliable engineering roadmaps for life prediction and risk assessment for hydrogen storage and transport structures.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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