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Slider design is one of the vital tasks in achieving mold development automation. This paper proposes an approach to automating the determination of undercut regions and their releasing directions for complex parts in STL format. The end result of research will provide an impactful tool for manufacturing automation, and further enhance our advance mold design and manufacturing abilities. Specific...
The designs of a 220 GHz folded waveguide traveling wave tube (FWTWT) have been reviewed and studied systematically via 3-D electromagnetic particle-in-cell (EM PIC) simulations. 3-D Cold test simulations using both the CFDTD and FEM methods have been carried out and compared with each other as basis for the hot test simulations. The hot test simulation results show that the gain-bandwidth features...
220 GHz FWTWT designs have been reviewed and studied via 3-D CFDTD PIC simulations. 3-D Cold test simulations using both the CFDTD and FEM methods have been carried out and compared with each other as basis for the hot test simulations. The preliminary simulation results show that the gain-bandwidth features at 220 GHz are achievable while carefully avoiding beam interceptions. It is found that that...
Human sensory systems allow individuals to see, hear, touch, and interact with the surrounding physical environment. Understanding human perception and its limit enables us to better exploit the psychophysics of human perceptual systems to design more efficient, adaptive algorithms and develop perceptually-inspired computational models., In this talk, I will survey some of recent efforts on perceptually-inspired...
Recently, permanent magnet (PM)-brushless direct current motors (BLDCMs) have been widely used in high-performance motor drive applications, thanks to their many attractive advantages, such as higher power and torque density and efficiency, simpler motor assembly and maintenance, lower cost, acoustic noise, and vibration. However, due to cost increase rapidly and restricted exploitation of rare earth...
Understanding and modeling how a crowd behaves in a wide variety of situations is an important problem in many areas. For example, during the planning stages, city, traffic, and evacuation engineers use crowd behavior modeling to predict usage patterns and to do safety analysis of their designs. Several research areas benefit from realistic simulation of crowds such as augmented reality, animation,...
In this work, an algorithm for coupling external circuit elements to electromagnetic (EM) particle-in-cell (PIC) simulations is developed. The circuit equation including an external voltage or current source, resistance, inductance, capacitance, and a dynamic load is solved simultaneously with the EM PIC updaters through an instant measured voltage across the system to obtain the supplied current...
Modeling a gyrotron cavity in 3D and timedomain is very challenging due to the open-end features of cavity structure and higher-order mode excitation employed to achieve high efficiency. In this work, a conformal finite-difference time-domain (CFDTD) method is proposed to simulate a gyrotron cavity and a particle-in-cell (PIC) algorithm is used to describe a gyro electron beam. Our preliminary result...
Low frequency oscillations (LFOs) have been obtained in a 3D time domain simulation for the first time. From our preliminary simulation studies, it is found that not only magnetic compression profile but initial velocity or velocity ratio play an important role in the operation of a MIG electron gun. In addition, the secondary emission effects on the LFOs are also studied. The frequency of LFOs has...
The feasibility of designing and modeling a multistage depressed collector (MDC) using 3D conformal finite-difference time-domain (CFDTD) particle-in-cell (PIC) simulations as implemented in VORPAL has been studied. A simple circuit model employing feedback mechanisms has been implemented to provide stable time-dependent voltages for each stage of the depressed collector and an arbitrary space-time...
With increasingly high currents flowing though CPU sockets in thermally-challenged systems, socket temperatures have recently been projected to approach, and even exceed, their thermal reliability limits. The prediction of socket and board temperatures through modeling and simulation is well-established and refined. The modeling methodology based on CFD simulation accounts for Joule heating power...
Low frequency oscillations (LFOs) have been obtained in a 3D time domain simulation for the first time. From our preliminary simulation studies, it is found that not only magnetic compression profile but initial velocity or velocity ratio play an important role in the operation of a MIG electron gun. In addition, the secondary emission effects on the LFOs are also studied. The frequency of LFOs has...
A progressive die is an effective tool for efficient and economical production of sheet metal parts in large quantities. Nowadays, progressive die designers still spend much of their time on choosing better layouts among feasible ones. This study employs Pro/Web.Link, Hyper Text Markup Language (HTML) and JavaScript to develop an application which helps evaluate automatically strip layouts in Pro/Engineer...
The feasibility of designing a multistage depressed collector using conformal finite-difference time-domain particle-in-cell simulations has been studied. A feedback mechanism is implemented to provide stable time-dependent voltages for each stage of the depressed collector. An arbitrary space-time dependent spent beam distribution can be given in our time-domain simulations. We demonstrate the design...
We present a new interaction handling model for physics-based sound synthesis in virtual environments. A new three-level surface representation for describing object shapes, visible surface bumpiness, and microscopic roughness (e.g. friction) is proposed to model surface contacts at varying resolutions for automatically simulating rich, complex contact sounds. This new model can capture various types...
This study modeled the Left Ventricular (LV) motion using parameters of myocardial twisting angle and shortening of LV long axis. Twenty two sets of the heart's volume-time curve (VTC) were analyzed. The ejection fraction (EF) of each data set was evaluated. The average of EF was 70.96 ?? 5.76%. The accuracy of model simulation was evaluated in each time frame. The average difference of volume between...
A 3-D object representation scheme which uses surfaces as primitives and grammatical production rules as structural relationship descriptors is proposed. Possible selections of surface primitives are discussed. Examples are given to illustrate the object description method.
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