Advanced large-scale and high-speed multiprocessor system for scientific applications

This study aimed to evaluate the effects playing position, match location (home or away), quality of opposition (strong or weak), effective playing time (total time minus stoppages), and score-line on physical match performance in professional soccer players using a large-scale analysis. A total of 10,739 individual match observations of outfield players competing in the Spanish La Liga during the 2018–2019 season were recorded using a computerized tracking system (TRACAB, Chyronhego, New York, USA). The players were classified into five positions (central defenders, players = 94; external defenders, players = 82; central midfielders, players = 101; external midfielders, players = 72; and forwards, players = 67) and the following match running performance categories were considered: total distance covered, low-speed running (LSR) distance (0–14 km · h−1), medium-speed running (MSR) distance (14–21 km · h−1), high-speed running (HSR) distance (>21 km · h−1), very HSR (VHSR) distance (21–24 km · h−1), sprint distance (>24 km · h−1) Overall, match running performance was highly dependent on situational variables, especially the score-line condition (winning, drawing, losing). Moreover, the score-line affected players running performance differently depending on their playing position. Losing status increased the total distance and the distance covered at MSR, HSR, VHSR and Sprint by defenders, while attacking players showed the opposite trend. These findings may help coaches and managers to better understand the effects of situational variables on physical performance in La Liga and could be used to develop a model for predicting the physical activity profile in competition.

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1.5 °C degrowth scenarios suggest the need for new mitigation pathways

Nature Communications ◽

10.1038/s41467-021-22884-9 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Lorenz T. Keyßer ◽

Manfred Lenzen

Keyword(s):

Technological Change ◽

High Speed ◽

Large Scale ◽

High Energy ◽

Climate Mitigation ◽

Intergovernmental Panel ◽

Economic Output ◽

Integrated Assessment Modelling ◽

Negative Emissions ◽

Energy Emissions

Abstract1.5 °C scenarios reported by the Intergovernmental Panel on Climate Change (IPCC) rely on combinations of controversial negative emissions and unprecedented technological change, while assuming continued growth in gross domestic product (GDP). Thus far, the integrated assessment modelling community and the IPCC have neglected to consider degrowth scenarios, where economic output declines due to stringent climate mitigation. Hence, their potential to avoid reliance on negative emissions and speculative rates of technological change remains unexplored. As a first step to address this gap, this paper compares 1.5 °C degrowth scenarios with IPCC archetype scenarios, using a simplified quantitative representation of the fuel-energy-emissions nexus. Here we find that the degrowth scenarios minimize many key risks for feasibility and sustainability compared to technology-driven pathways, such as the reliance on high energy-GDP decoupling, large-scale carbon dioxide removal and large-scale and high-speed renewable energy transformation. However, substantial challenges remain regarding political feasibility. Nevertheless, degrowth pathways should be thoroughly considered.

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Prevention of Mountain Disasters and Maintenance of Residential Area through Real-Time Terrain Rendering

Sustainability ◽

10.3390/su13052950 ◽

2021 ◽

Vol 13 (5) ◽

pp. 2950

Author(s):

Su-Kyung Sung ◽

Eun-Seok Lee ◽

Byeong-Seok Shin

Keyword(s):

Real Time ◽

Graphics Processing Units ◽

High Speed ◽

Large Scale ◽

Civil Engineering ◽

Three Dimensional ◽

Sampled Data ◽

Residential Areas ◽

Terrain Rendering ◽

Mountain Disasters

Climate change increases the frequency of localized heavy rains and typhoons. As a result, mountain disasters, such as landslides and earthworks, continue to occur, causing damage to roads and residential areas downstream. Moreover, large-scale civil engineering works, including dam construction, cause rapid changes in the terrain, which harm the stability of residential areas. Disasters, such as landslides and earthenware, occur extensively, and there are limitations in the field of investigation; thus, there are many studies being conducted to model terrain geometrically and to observe changes in terrain according to external factors. However, conventional topography methods are expressed in a way that can only be interpreted by people with specialized knowledge. Therefore, there is a lack of consideration for three-dimensional visualization that helps non-experts understand. We need a way to express changes in terrain in real time and to make it intuitive for non-experts to understand. In conventional height-based terrain modeling and simulation, there is a problem in which some of the sampled data are irregularly distorted and do not show the exact terrain shape. The proposed method utilizes a hierarchical vertex cohesion map to correct inaccurately modeled terrain caused by uniform height sampling, and to compensate for geometric errors using Hausdorff distances, while not considering only the elevation difference of the terrain. The mesh reconstruction, which triangulates the three-vertex placed at each location and makes it the smallest unit of 3D model data, can be done at high speed on graphics processing units (GPUs). Our experiments confirm that it is possible to express changes in terrain accurately and quickly compared with existing methods. These functions can improve the sustainability of residential spaces by predicting the damage caused by mountainous disasters or civil engineering works around the city and make it easy for non-experts to understand.

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Study on the High-Speed Milling Performance of High-Volume Fraction SiCp/Al Composites

Materials ◽

10.3390/ma14154143 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4143

Author(s):

Youzheng Cui ◽

Shenrou Gao ◽

Fengjuan Wang ◽

Qingming Hu ◽

Cheng Xu ◽

...

Keyword(s):

High Speed ◽

Large Scale ◽

Volume Fraction ◽

Simulation Analysis ◽

Cutting Temperature ◽

High Volume ◽

Cutting Parameters ◽

High Volume Fraction ◽

High Wear Resistance ◽

Element Analysis

Compared with other materials, high-volume fraction aluminum-based silicon carbide composites (hereinafter referred to as SiCp/Al) have many advantages, including high strength, small change in the expansion coefficient due to temperature, high wear resistance, high corrosion resistance, high fatigue resistance, low density, good dimensional stability, and thermal conductivity. SiCp/Al composites have been widely used in aerospace, ordnance, transportation service, precision instruments, and in many other fields. In this study, the ABAQUS/explicit large-scale finite element analysis platform was used to simulate the milling process of SiCp/Al composites. By changing the parameters of the tool angle, milling depth, and milling speed, the influence of these parameters on the cutting force, cutting temperature, cutting stress, and cutting chips was studied. Optimization of the parameters was based on the above change rules to obtain the best processing combination of parameters. Then, the causes of surface machining defects, such as deep pits, shallow pits, and bulges, were simulated and discussed. Finally, the best cutting parameters obtained through simulation analysis was the tool rake angle γ0 = 5°, tool clearance angle α0 = 5°, corner radius r = 0.4 mm, milling depth ap = 50 mm, and milling speed vc= 300 m/min. The optimal combination of milling parameters provides a theoretical basis for subsequent cutting.

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Catalytic production of impurity-free V3.5+ electrolyte for vanadium redox flow batteries

Nature Communications ◽

10.1038/s41467-019-12363-7 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 5

Author(s):

Jiyun Heo ◽

Jae-Yun Han ◽

Soohyun Kim ◽

Seongmin Yuk ◽

Chanyong Choi ◽

...

Keyword(s):

High Speed ◽

High Performance ◽

Large Scale ◽

Catalytic Reduction ◽

Continuous Production ◽

Vanadium Redox Flow Battery ◽

Manufacturing Cost ◽

Chemical Production ◽

High Manufacturing Cost ◽

Vanadium Redox

Abstract The vanadium redox flow battery is considered one of the most promising candidates for use in large-scale energy storage systems. However, its commercialization has been hindered due to the high manufacturing cost of the vanadium electrolyte, which is currently prepared using a costly electrolysis method with limited productivity. In this work, we present a simpler method for chemical production of impurity-free V3.5+ electrolyte by utilizing formic acid as a reducing agent and Pt/C as a catalyst. With the catalytic reduction of V4+ electrolyte, a high quality V3.5+ electrolyte was successfully produced and excellent cell performance was achieved. Based on the result, a prototype catalytic reactor employing Pt/C-decorated carbon felt was designed, and high-speed, continuous production of V3.5+ electrolyte in this manner was demonstrated with the reactor. This invention offers a simple but practical strategy to reduce the production cost of V3.5+ electrolyte while retaining quality that is adequate for high-performance operations.

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Numerical Modeling and Simulation Analysis of Temperature Field of Disc Brake on Trains

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.199-200.1492 ◽

2011 ◽

Vol 199-200 ◽

pp. 1492-1495 ◽

Cited By ~ 1

Author(s):

Guo Shun Wang ◽

Rong Fu ◽

Liang Zhao

Keyword(s):

Temperature Field ◽

Temperature Gradient ◽

High Speed ◽

Large Scale ◽

Working Condition ◽

Constant Speed ◽

Brake Disc ◽

Disc Brake ◽

Brake Pad ◽

Finite Element Software

The simulation calculation on the temperature field of the disc brake system on high-speed trains under the working condition of constant speed at 50Km/h is made. A steady-state calculation model is established according to the actual geometric size of a brake disc and a brake pad, and the analog calculation and simulation on the temperature field of the brake disc and the brake pad by using the large-scale nonlinear finite element software ABAQUS are carried out. The distribution rules of the temperature field of the brake disc and the brake pad under the working condition of constant speed are made known. The surface temperature of the brake disc at friction radius is the highest, with a band distribution for temperature. There exists a temperature flex point in the direction of thickness, of which the thickness occupies 15% of that of the brake disc; due to the small volume of the brake pad, the temperature gradient of the whole brake pad is not sharp, and larger temperature gradient occurs only on the contact surface.

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Steady longitudinal vortices in supersonic turbulent separated flows

Journal of Fluid Mechanics ◽

10.1017/s0022112010006105 ◽

2011 ◽

Vol 672 ◽

pp. 451-476 ◽

Cited By ~ 14

Author(s):

ERICH SCHÜLEIN ◽

VICTOR M. TROFIMOV

Keyword(s):

High Speed ◽

Large Scale ◽

Roughness Element ◽

Vortex Generator ◽

Vortex Pair ◽

Leading Edge ◽

Separated Flows ◽

Vortex Generators ◽

Longitudinal Vortices ◽

Oil Flow

Large-scale longitudinal vortices in high-speed turbulent separated flows caused by relatively small irregularities at the model leading edges or at the model surfaces are investigated in this paper. Oil-flow visualization and infrared thermography techniques were applied in the wind tunnel tests at Mach numbers 3 and 5 to investigate the nominally 2-D ramp flow at deflection angles of 20°, 25° and 30°. The surface contour anomalies have been artificially simulated by very thin strips (vortex generators) of different shapes and thicknesses attached to the model surface. It is shown that the introduced streamwise vortical disturbances survive over very large downstream distances of the order of 104 vortex-generator heights in turbulent supersonic flows without pressure gradients. It is demonstrated that each vortex pair induced in the reattachment region of the ramp is definitely a child of a vortex pair, which was generated originally, for instance, by the small roughness element near the leading edge. The dependence of the spacing and intensity of the observed longitudinal vortices on the introduced disturbances (thickness and spanwise size of vortex generators) and on the flow parameters (Reynolds numbers, boundary-layer thickness, compression corner angles, etc.) has been shown experimentally.

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