The Sensitivity Simulation of Different Geometric Pretreatment in Method of Characteristics

2017 ◽  
Author(s):  
Tian XiaoRui ◽  
Zhou Tao ◽  
Li Zichao ◽  
Yu Tao
Keyword(s):  
Computational Efficiency ◽  
Method Of Characteristics ◽  
Azimuthal Angle ◽  
Reactor Core ◽  
Characteristic Line ◽  
Simulation Results ◽  
And Storage

In reactor core physics analysis,the research about the pre-processing of Method of Characteristic (MOC) including the generation and storage of characteristic line,the progress of calculation and the choosing of different quadrature set.In addition,doing some simulations,which is based on OpenMOC code and C5G7-MOX benchmark,about different parameters (including the track spacing,azimuthal angles and polar angles) and calculated its impacts on the computational efficiency and accuracy.the simulation results are as following:setting the track spacing as 0.1 cm or the azimuthal angle number as 4,the simulation results have better accuracy. Whether choosing the Leonard’s optimum quadrature set or the Tabuchi-Yamamoto quadrature set,the number of polar angles have tiny impact on accuracy.

scholarly journals Client-Driven Joint Cache Management and Rate Adaptation for Dynamic Adaptive Streaming over HTTP

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Chenghao Liu ◽  
Miska M. Hannuksela ◽  
Moncef Gabbouj
Keyword(s):  
Rate Adaptation ◽  
Cache Management ◽  
Adaptive Streaming ◽  
Adaptation Algorithm ◽  
Proxy Cache ◽  
Proxy Caches ◽  
Simulation Results ◽  
And Storage ◽  
Media Data ◽  
Adaptation Method

Due to the fact that proxy-driven proxy cache management and the client-driven streaming solution of Dynamic Adaptive Streaming over HTTP (DASH) are two independent processes, some difficulties and challenges arise in media data management at the proxy cache and rate adaptation at the DASH client. This paper presents a novel client-driven joint proxy cache management and DASH rate adaptation method, named CLICRA, which moves prefetching intelligence from the proxy cache to the client. Based on the philosophy of CLICRA, this paper proposes a rate adaptation algorithm, which selects bitrates for the next media segments to be requested by using the predicted buffered media time in the client. CLICRA is realized by conveying information on the segments that are likely to be fetched subsequently to the proxy cache so that it can use the information for prefetching. Simulation results show that the proposed method outperforms the conventional segment-fetch-time-based rate adaptation and the proxy-driven proxy cache management significantly not only in streaming quality at the client but also in bandwidth and storage usage in proxy caches.

Effect of Relative Height between Water Tank and Collector on Performance of Thermosyphon Solar Water Heater

2011 ◽  
Vol 71-78 ◽  
pp. 2736-2739 ◽  
Author(s):  
Sheng Xian Wei ◽  
Cui Qiong Yan ◽  
You Ming Shi
Keyword(s):  
Maximum Efficiency ◽  
Water Tank ◽  
Solar Water Heater ◽  
Relative Height ◽  
Water Heater ◽  
Good Accordance ◽  
Tank Capacity ◽  
National Testing ◽  
Simulation Results ◽  
And Storage

The effect of relative height between the bottom of the tank and the top of the collector on performance has been studied both theoreticaly and experimentally. According to the national testing standard methods, the efficiency of the system was tested. The results show that the simulation results are in good accordance with the experimental ones. The data indicate that the optimum value of relative height is 0.74m with the maximum efficiency of 67.7% for the system with a total area of 1.5m2 and storage water tank capacity of 120L. Increasing or decreasing the relative height within a range of 0.3m has no significant effect on thermal efficiency.

scholarly journals Changes In The Axon Initiation Segment Of Thalamic Neurons In Response To Cyclical Stimulation

2018 ◽  
Author(s):  
Mark Zirkov ◽  
Yelena Kolezeva
Keyword(s):  
Water Potential ◽  
Low Voltage ◽  
Early Disease ◽  
Thalamic Neurons ◽  
Change Rate ◽  
Disease States ◽  
Degenerative Disorders ◽  
Simulation Results ◽  
Free Media ◽  
And Storage

AbstractChanges to the axon initiation segment in frequently firing neurons are known to be important predictors of early disease states. Studying this phenomenon in thalamic neurons is critical to understanding the first insult implicated in multiple neuro-degenerative disorders. To study these changes we used cyclical stimulations using micro-electrodes to the axon initiation segment of mouse thalamic neurons. Numerical simulation results indicate that axon initiation segment water potential fluctuated sinusoidally on high voltage only. Fluctuations in the amplitude and trend were caused by calcium flow and storage resistance, respectively. The change in axon initiation segment-stored water was proportional to the change rate in water potential. Axon initiation segment diameter increased with fluctuations in calcium free media; moreover, it varied slightly under low voltage conditions. Our results indicate that the changes in axon initiation segment diameter were caused by changes in water potential, which can be attributed to subcellular gated calcium channels within the thalamic neurons.

scholarly journals The effect of cyclical stimulation on the primary neurons of Bombyx Mori

2018 ◽  
Author(s):  
Yeti Zuko ◽  
Kazuo Maeda
Keyword(s):  
Numerical Simulation ◽  
Water Potential ◽  
Bombyx Mori ◽  
Low Voltage ◽  
Primary Neurons ◽  
Change Rate ◽  
Silk Production ◽  
Simulation Results ◽  
Free Media ◽  
And Storage

Changes to the Silkworm axon initiation segment in frequently firing neurons are known to be important predictors of silk production in the Japanese Silkworm (Bombyx Mori). Studying this phenomenon in primary neurons is critical to understanding the regulation of silk production. To study these changes we used cyclical stimulations using micro-electrodes to the Silkworm axon initiation segment of primary neurons. Numerical simulation results indicate that Silkworm axon initiation segment water potential fluctuated sinusoidally on high voltage only. Fluctuations in the amplitude and trend were caused by calcium flow and storage resistance, respectively. The change in Silkworm axon initiation segment-stored water was proportional to the change rate in water potential. Silkworm axon initiation segment diameter increased with fluctuations in calcium free media; moreover, it varied slightly under low voltage conditions. Our results indicate that the changes in Silkworm axon initiation segment diameter were caused by changes in water potential, which can be attributed to subcellular gated calcium channels within the primary neurons.

scholarly journals Coupled DEM-SPH Method for Interaction between Dilated Polyhedral Particles and Fluid

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Shunying Ji ◽  
Xiaodong Chen ◽  
Lu Liu
Keyword(s):  
Numerical Simulation ◽  
Parallel Algorithm ◽  
Granular Materials ◽  
Computational Efficiency ◽  
Dam Break ◽  
Solid Interface ◽  
Fluid Media ◽  
Complex Fluid ◽  
Simulation Results ◽  
The Impact

The discrete element method (DEM) and smoothed particle hydrodynamics (SPH) can be adopted to simulate the granular materials and fluid media respectively. The DEM-SPH coupling algorithm can be developed for the dynamic interaction between the two media. When the particle material is simulated by polyhedral element, a fluid-solid coupling interface would lead to the complex geometry between the granular particle and the fluid. The boundary particle method is traditionally used for the fluid-solid interface but with low computational efficiency. In this paper, the dilated polyhedral element is constructed based on Minkowski sum theory, while the contact force between the elements is calculated by Hertzian contact model. Accordingly the dilated polyhedra based DEM is established. The weakly compressible SPH is adopted to simulate the fluid medium, while the interaction on the geometrically complex fluid-solid interface is evaluated with the repulsive force model which can be determined by the contact detection between SPH particles and solid particles in geometry. This method avoids the storage and calculation of a large number of boundary particles, which can be potentially applied for the complex fluid-solid boundary. In order to improve the computational efficiency, a GPU-based parallel algorithm is employed to achieve high performance computation of SPH. The acceleration of the parallel algorithm is evaluated by the cases of dam break. The numerical simulation of the impact of dam break on cubes is implemented. The simulation results are verified with the corresponding experimental and simulation results. Therefore, the rationality and accuracy of the DEM-SPH coupling method for numerical simulation of the interaction between granular materials and fluid media are illustrated. This method is then adopted for the impact of falling rocks on underwater pipeline. The force of water and rocks on the pipeline is analyzed. This method can be further applied for real engineering problems.

scholarly journals Joint-2D-SL0 Algorithm for Joint Sparse Matrix Reconstruction

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Dong Zhang ◽  
Yongshun Zhang ◽  
Cunqian Feng
Keyword(s):  
Computational Efficiency ◽  
Taylor Expansion ◽  
Sparse Matrix ◽  
Doa Estimation ◽  
Reconstruction Problem ◽  
Reconstruction Accuracy ◽  
Mismatch Problem ◽  
Matrix Reconstruction ◽  
Simulation Results ◽  
Reconstruction Model

Sparse matrix reconstruction has a wide application such as DOA estimation and STAP. However, its performance is usually restricted by the grid mismatch problem. In this paper, we revise the sparse matrix reconstruction model and propose the joint sparse matrix reconstruction model based on one-order Taylor expansion. And it can overcome the grid mismatch problem. Then, we put forward the Joint-2D-SL0 algorithm which can solve the joint sparse matrix reconstruction problem efficiently. Compared with the Kronecker compressive sensing method, our proposed method has a higher computational efficiency and acceptable reconstruction accuracy. Finally, simulation results validate the superiority of the proposed method.

scholarly journals Poisson Denoising for Astronomical Images

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Fahad Shamshad ◽  
M. Mohsin Riaz ◽  
Abdul Ghafoor
Keyword(s):  
Principal Component Analysis ◽  
Computational Efficiency ◽  
Color Space ◽  
Principal Component ◽  
Color Images ◽  
Temporal Correlations ◽  
Image Patches ◽  
Quantitative Manner ◽  
Simulation Results ◽  
Astronomical Images

A denoising scheme for astronomical color images/videos corrupted with Poisson noise is proposed. The scheme employs the concept of Exponential Principal Component Analysis and sparsity of image patches. The color space RGB is converted to YCbCr and K-means++ clustering is applied on luminance component only. The cluster centers are used for chromatic components to improve the computational efficiency. For videos, the information of both spatial and temporal correlations improves the denoising. Simulation results verify the significance of proposed scheme in both visual and quantitative manner.

A PRELIMINARY CATHENA THERMALHYDRAULIC MODEL OF THE CANADIAN SCWR FOR SAFETY ANALYSIS

2014 ◽  
Vol 3 (01) ◽  
pp. 9-16 ◽  
Author(s):  
D.F. Wang ◽  
S. Wang
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Conceptual Design ◽  
Reactor Core ◽  
International Forum ◽  
Detailed Model ◽  
Tube Type ◽  
Simulation Results ◽  
Supercritical Water Cooled Reactor ◽  
Water Moderator

The supercritical water-cooled reactor (SCWR) is one of six reactor concepts under development in the Generation-IV International Forum (GIF). As a member of GIF, Canada is developing a pressure-tube type SCWR, which has the potential to fulfill all major GIF goals on enhanced safety, sustainability, economics, and proliferation resistance. The system thermalhydraulics code CATHENA will be used in the safety analyses for the Canadian SCWR. Based on the current conceptual design of the Canadian SCWR, a CATHENA idealization has been developed. This model includes all 336 fuel channels with a detailed model of heat transfer in the reactor core. Also modeled are the main pumps, inlet plenum, outlet plenum, turbines, and heavy water moderator. In this paper, the CATHENA idealization of the Canadian SCWR conceptual design is described. Simulation results for steady-state normal operations are also presented for the current Canadian SCWR conceptual design.

Rasterized coarse mesh finite difference acceleration on method of characteristics for a reactor core with a generalized boundary

2021 ◽  
Vol 162 ◽  
pp. 108483
Author(s):  
Ao Zhang ◽  
Ming Dai ◽  
Maosong Cheng ◽  
Jianhui Wu ◽  
Chunyan Zou ◽  
...  
Keyword(s):  
Finite Difference ◽  
Method Of Characteristics ◽  
Reactor Core ◽  
Coarse Mesh

Parametric dependence of lightning impulse behavior of grounding electrodes buried in a dispersive and ionized lossy soil under first- and subsequent-stroke currents

2020 ◽  
Vol 39 (4) ◽  
pp. 757-773 ◽  
Author(s):  
Seyed Sajad Sajadi ◽  
Saeed Reza Ostadzadeh ◽  
Seyed Hossein Hesamedin Sadeghi
Keyword(s):  
Computational Efficiency ◽  
Design Methodology ◽  
Soil Surface ◽  
Effective Length ◽  
Sensitivity Analyses ◽  
Induced Voltage ◽  
Content Type ◽  
Parametric Dependence ◽  
Lightning Impulse ◽  
Simulation Results

Purpose The purpose of this paper is to investigate the simultaneous effects of ionization and dispersion of soil on the impulse behavior of grounding electrodes under first and subsequent stroke currents. Design/methodology/approach A recently introduced technique called improved multi-conductor transmission line (MTL) is simplified for grounding electrodes buried in both-affected soils. Findings The simulation results show that including the two effects simultaneously in highly resistive soils under high-valued subsequent stroke current is recommended. Otherwise, simultaneous effects can be disregard. Originality/value To the best of the authors’ knowledge, there is no research on sensitivity analyses for the simultaneous inclusion of the two effects on the effective length and the induced voltage on the soil surface. To this end, the simplified MTL is applied to the grounding electrodes. The simulation results show that the computational efficiency in comparison with previous methods is, first, considerably increased. Second, the simultaneous effects result in decreasing the soil surface voltage with respect to situations where either ionization or dispersion is taken into account (single-affected soils). In other words, the performance of grounding systems is improved. Third, the effective length in both-affected soil is has a middle value with respect to the single-affected soil. Such findings practically and financially are of importance.

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