Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 6 of 6
Full-Text Articles in Entire DC Network
A Two-Dimensional Simulation Of Grain Structure Growth Within Substrate And Fusion Zone During Direct Metal Deposition, Jingwei Zhang, Lei Yan, Wei Li, Frank W. Liou
A Two-Dimensional Simulation Of Grain Structure Growth Within Substrate And Fusion Zone During Direct Metal Deposition, Jingwei Zhang, Lei Yan, Wei Li, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this chapter, a predictive multiscale model based on a cellular automaton (CA)-finite element (FE) method has been developed to simulate thermal history and microstructure evolution during metal solidification for direct metal deposition (DMD) process. The macroscopic FE calculation that is validated by the thermocouple experiment is developed to simulate the transient temperature field and cooling rate of single layer and multiple layers. In order to integrate the different scales, a CA-FE coupled model is developed to combine with thermal history and simulate grain growth. In the mesoscopic CA model, heterogeneous nucleation sites, grain growth orientation and rate, epitaxial growth, …
Probabilistic Simulation Of Solidification Microstructure Evolution During Laser-Based Metal Deposition, Jingwei Zhang, Frank W. Liou, William Seufzer, Joseph William Newkirk, Zhiqiang Fan, Heng Liu, Todd E. Sparks
Probabilistic Simulation Of Solidification Microstructure Evolution During Laser-Based Metal Deposition, Jingwei Zhang, Frank W. Liou, William Seufzer, Joseph William Newkirk, Zhiqiang Fan, Heng Liu, Todd E. Sparks
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A predictive model, based on a Cellular Automaton (CA) - Finite Element (FE) method, has been developed to simulate microstructure evolution during metal solidification for a laser based additive manufacturing process. The macroscopic FE calculation was designed to update the temperature field and simulate a high cooling rate. In the microscopic CA model, heterogeneous nucleation sites, preferential growth orientation and dendritic grain growth kinetics were simulated. The CA model was able to show the entrapment of neighboring cells and the relationship between undercooling and the grain growth rate. The model predicted the dendritic grain size, structure, and morphological evolution during …
Numerical Simulation Of The Evolution Of Solidification Microstructure In Laser Deposition, Zhiqiang Fan, Todd E. Sparks, Frank W. Liou, Anand Jambunathan, Yaxin Bao, Jianzhong Ruan, Joseph William Newkirk
Numerical Simulation Of The Evolution Of Solidification Microstructure In Laser Deposition, Zhiqiang Fan, Todd E. Sparks, Frank W. Liou, Anand Jambunathan, Yaxin Bao, Jianzhong Ruan, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A predictive model is developed to simulate the evolution of the solidification microstructure during the laser deposition process. The microstructure model is coupled with a comprehensive macroscopic thermodynamic model. This model simulates dendritic grain structures and morphological evolution in solidification. Based on the cellular automata approach, this microstructure model takes into account the heterogeneous nucleation both within the melt pool and at the substrate/melt interface, the growth kinetics, and preferential growth directions of dendrites. Both diffusion and convection effects are included. This model enables prediction and visualization of grain structures during and after the deposition process. This model is applied …
Efficient And Robust Delay-Insensitive Qca (Quantum-Dot Cellular Automata) Design, Minsu Choi, Myungsu Choi, Zachary D. Patitz, Nohpill Park
Efficient And Robust Delay-Insensitive Qca (Quantum-Dot Cellular Automata) Design, Minsu Choi, Myungsu Choi, Zachary D. Patitz, Nohpill Park
Electrical and Computer Engineering Faculty Research & Creative Works
The concept of clocking for QCA, referred to as the four-phase clocking, is widely used. However, inherited characteristics of QCA, such as the way to hold state, the way to synchronize data flows, and the way to power QCA cells, make the design of QCA circuits quite different from VLSI and introduce a variety of new design challenges. The most severe challenges are due to the fact that the overall timing of a QCA circuit is mainly dependent upon its layout. This issue is commonly referred to as the "layout =timing" problem. To circumvent the problem, a novel self-timed circuit …
Qca-Based Majority Gate Design Under Radius Of Effect-Induced Faults, Zachary D. Patitz, Nohpill Park, Minsu Choi, Fred J. Meyer
Qca-Based Majority Gate Design Under Radius Of Effect-Induced Faults, Zachary D. Patitz, Nohpill Park, Minsu Choi, Fred J. Meyer
Electrical and Computer Engineering Faculty Research & Creative Works
This paper presents reliable QCA cell structures for designing single clock-controlled majority gates with a tolerance to radius of effect-induced faults, for use as a basic building component for carry look-ahead adder. Realizable quantum computing is still well in the future due to the complexity of the quantum mechanics that govern them. In this regard, QCA-based system design is a challenging task since each cell''s state must interact with all the cells that are in its energy-effective range in its clocking zone, referred to as its radius of effect. This paper proposes a design approach for majority gates to overcome …
Teaching Nanotechnology By Introducing Crossbar-Based Architecture And Quantum-Dot Cellular Automata, Minsu Choi, Nohpill Park
Teaching Nanotechnology By Introducing Crossbar-Based Architecture And Quantum-Dot Cellular Automata, Minsu Choi, Nohpill Park
Electrical and Computer Engineering Faculty Research & Creative Works
The end of photolithography as the driver for Moore's law is predicted within seven to twelve years and six different emerging technologies (mostly nanoscale) are expected to replace the current CMOS-based system integration paradigm. As nanotechnology is emerging, (1) there is a strong need for well-educated nanoscale systems engineers by industry, and (2) research and education efforts are also called to overcome numerous nanoscale systems issues. This paper is to propose a way to teach nanotechnology by introducing two emerging technologies: crossbar-based nanoarchitecture and quantum-dot cellular automata.