scholarly journals On Contraction of Three-Dimensional Multiple Shear Mechanism Model for Evaluation of Large Scale Liquefaction Using High Performance Computing

Geosciences ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 38
Author(s):  
Wataru Hotta ◽  
Shunichi Suzuki ◽  
Muneo Hori

For more reliable evaluation of liquefaction, an analysis model of higher fidelity should be used even though it requires more numerical computation. We developed a parallel finite element method (FEM), implemented with the non-linear multiple shear mechanism model. A bottleneck experienced when implementing the model is the use of vast amounts of CPU memory for material state parameters. We succeeded in drastically reducing the computation requirements of the model by suitably approximating the formulation of the model. An analysis model of high fidelity was constructed for a soil-structure system, and the model was analyzed by using the developed parallel FEM on a parallel computer. The amount of required CPU memory was reduced. The computation time was reduced as well, and the practical applicability of the developed parallel FEM is demonstrated.

Author(s):  
Vinay Sriram ◽  
David Kearney

High speed infrared (IR) scene simulation is used extensively in defense and homeland security to test sensitivity of IR cameras and accuracy of IR threat detection and tracking algorithms used commonly in IR missile approach warning systems (MAWS). A typical MAWS requires an input scene rate of over 100 scenes/second. Infrared scene simulations typically take 32 minutes to simulate a single IR scene that accounts for effects of atmospheric turbulence, refraction, optical blurring and charge-coupled device (CCD) camera electronic noise on a Pentium 4 (2.8GHz) dual core processor [7]. Thus, in IR scene simulation, the processing power of modern computers is a limiting factor. In this paper we report our research to accelerate IR scene simulation using high performance reconfigurable computing. We constructed a multi Field Programmable Gate Array (FPGA) hardware acceleration platform and accelerated a key computationally intensive IR algorithm over the hardware acceleration platform. We were successful in reducing the computation time of IR scene simulation by over 36%. This research acts as a unique case study for accelerating large scale defense simulations using a high performance multi-FPGA reconfigurable computer.


2018 ◽  
Vol 7 (12) ◽  
pp. 467 ◽  
Author(s):  
Mengyu Ma ◽  
Ye Wu ◽  
Wenze Luo ◽  
Luo Chen ◽  
Jun Li ◽  
...  

Buffer analysis, a fundamental function in a geographic information system (GIS), identifies areas by the surrounding geographic features within a given distance. Real-time buffer analysis for large-scale spatial data remains a challenging problem since the computational scales of conventional data-oriented methods expand rapidly with increasing data volume. In this paper, we introduce HiBuffer, a visualization-oriented model for real-time buffer analysis. An efficient buffer generation method is proposed which introduces spatial indexes and a corresponding query strategy. Buffer results are organized into a tile-pyramid structure to enable stepless zooming. Moreover, a fully optimized hybrid parallel processing architecture is proposed for the real-time buffer analysis of large-scale spatial data. Experiments using real-world datasets show that our approach can reduce computation time by up to several orders of magnitude while preserving superior visualization effects. Additional experiments were conducted to analyze the influence of spatial data density, buffer radius, and request rate on HiBuffer performance, and the results demonstrate the adaptability and stability of HiBuffer. The parallel scalability of HiBuffer was also tested, showing that HiBuffer achieves high performance of parallel acceleration. Experimental results verify that HiBuffer is capable of handling 10-million-scale data.


Author(s):  
Hui Huang ◽  
Jian Chen ◽  
Blair Carlson ◽  
Hui-Ping Wang ◽  
Paul Crooker ◽  
...  

Due to enormous computation cost, current residual stress simulation of multipass girth welds are mostly performed using two-dimensional (2D) axisymmetric models. The 2D model can only provide limited estimation on the residual stresses by assuming its axisymmetric distribution. In this study, a highly efficient thermal-mechanical finite element code for three dimensional (3D) model has been developed based on high performance Graphics Processing Unit (GPU) computers. Our code is further accelerated by considering the unique physics associated with welding processes that are characterized by steep temperature gradient and a moving arc heat source. It is capable of modeling large-scale welding problems that cannot be easily handled by the existing commercial simulation tools. To demonstrate the accuracy and efficiency, our code was compared with a commercial software by simulating a 3D multi-pass girth weld model with over 1 million elements. Our code achieved comparable solution accuracy with respect to the commercial one but with over 100 times saving on computational cost. Moreover, the three-dimensional analysis demonstrated more realistic stress distribution that is not axisymmetric in hoop direction.


NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050062
Author(s):  
Zhaolei Meng ◽  
Xiaojian He ◽  
Song Han ◽  
Zijian Hu

Carbon materials are generally employed as supercapacitor electrodes due to their low- cost, high-chemical stability and environmental friendliness. However, the design of carbon structures with large surface area and controllable porous structure remains a daunt challenge. In this work, a three-dimensional (3D) hybrid aerogel with different contents of MoS2 nanosheets in 3D graphene aerogel (MoS2-GA) was synthesized through a facial hydrothermal process. The influences of MoS2 content on microstructure and subsequently on electrochemical properties of MoS2-GA are systematically investigated and an optimized mass ratio with MoS2: GA of 1:2 is chosen to achieve high mechanical robustness and outstanding electrochemical performance in the hybrid structure. Due to the large specific surface area, porous structure and continuous charge transfer network, such MoS2-GA electrodes exhibit high specific capacitance, good rate capability and excellent cyclic stability, showing great potential in large-scale and low-cost fabrication of high-performance supercapacitors.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Jing Ning ◽  
Maoyang Xia ◽  
Dong Wang ◽  
Xin Feng ◽  
Hong Zhou ◽  
...  

Abstract Recent developments in the synthesis of graphene-based structures focus on continuous improvement of porous nanostructures, doping of thin films, and mechanisms for the construction of three-dimensional architectures. Herein, we synthesize creeper-like Ni3Si2/NiOOH/graphene nanostructures via low-pressure all-solid melting-reconstruction chemical vapor deposition. In a carbon-rich atmosphere, high-energy atoms bombard the Ni and Si surface, and reduce the free energy in the thermodynamic equilibrium of solid Ni–Si particles, considerably catalyzing the growth of Ni–Si nanocrystals. By controlling the carbon source content, a Ni3Si2 single crystal with high crystallinity and good homogeneity is stably synthesized. Electrochemical measurements indicate that the nanostructures exhibit an ultrahigh specific capacity of 835.3 C g−1 (1193.28 F g−1) at 1 A g−1; when integrated as an all-solid-state supercapacitor, it provides a remarkable energy density as high as 25.9 Wh kg−1 at 750 W kg−1, which can be attributed to the free-standing Ni3Si2/graphene skeleton providing a large specific area and NiOOH inhibits insulation on the electrode surface in an alkaline solution, thereby accelerating the electron exchange rate. The growth of the high-performance composite nanostructure is simple and controllable, enabling the large-scale production and application of microenergy storage devices.


1993 ◽  
Vol 16 (12) ◽  
pp. 843-846 ◽  
Author(s):  
J.C. Gerlach ◽  
K. Klöppel ◽  
C. MÜller ◽  
N. Schnoy ◽  
M.D. Smith ◽  
...  

Utilizing a modified culture technique for hepatocytes, a high performance suspension culture is possible in which hepatocytes spontaneously form cell aggregates. The aggregates of 20-100 cells have been histologically confirmed to hold a three-dimensional structure, they show a long-term external metabolism and a survival time comparable with standard adhesion cultures. This technique has several advantages in the construction of large scale bioreactors for hybrid liver support systems.


Author(s):  
Seshu Nimmala ◽  
Solomon Yim ◽  
Stephan Grilli

This paper presents an accurate and efficient three-dimensional computational model (3D numerical wave tank), based on fully nonlinear potential flow (FNPF) theory, and its extension to incorporate the motion of a laboratory snake piston wavemaker, to simulate experiments in a large-scale 3D wave basin (i.e. to conduct “virtual” or numerical experiments). The code is based on a higher-order boundary element method combined with a Fast Multipole Algorithm (FMA). Particular efforts were devoted to making the code efficient for large-scale simulations using high-performance computing platforms to complement experimental 3D wave basins. The numerical simulation capability can serve as an optimization tool at the experimental planning and detailed design stages. To date, waves that can be generated in the NWT include solitary, Cnoidal, and Airy waves. In this paper, we detail the model, mathematical formulation, and wave generation. Experimental or analytical comparisons with NWT results are provided for several cases to assess the accuracy and applicability of the numerical model to practical engineering problems.


2017 ◽  
Vol 25 (02) ◽  
pp. 1750011 ◽  
Author(s):  
Xuan Quang Duong ◽  
Jae Dong Chung

A three-dimensional simulation of a compressor dehumidifier was conducted by applying a porous model for condenser and evaporator, and a moving reference frame for the fan. A physical model was simulated for the unit cell of the actual shape of a fin-tube, and the parameters of viscous resistance and initial resistance were obtained. With these values, the porous model showed close agreement with the physical model within a reasonable computation time. A uniform flow across the evaporator and the condenser is desirable for high performance of the dehumidifier. Surface averaged velocity, standard deviation of velocity, and uniformity were chosen as indicators of the design object. A case study showed that two factors, (i) reducing the space between the evaporator and the condenser and (ii) introducing a cover to reduce the by-passing air flow, have the strongest influence on the air distribution in this dehumidifier.


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