scholarly journals Hydraulic Fracturing Simulations with Real-Time Evolution of Physical Parameters

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1678
Author(s):  
Qiuping Qin ◽  
Qingfeng Xue ◽  
Zizhuo Ma ◽  
Yikang Zheng ◽  
Hongyu Zhai
Keyword(s):  
Hydraulic Fracturing ◽  
Numerical Simulations ◽  
Real Time ◽  
Time Evolution ◽  
Physical Parameter ◽  
Damage Evolution ◽  
Velocity Variation ◽  
Physical Parameters ◽  
Rock Damage ◽  
Simulation Results

During hydraulic fracturing, expansion of internal micro-fractures deforms the rock to different extents. Numerical studies typically assume fixed parameters; however, in the field site, parameters are likely to vary. Error accumulation underlies deviation of simulation results from actual data. In this study, it was found that the mean velocity of an in-lab active source obtained from the hydraulic fracturing experiment decreased. To explain the effect of physical parameter (velocity) on numerical simulation results, we performed numerical simulations based on the extended finite element method (XFEM) of indoor hydraulic fracturing considering the velocity variation. The simulation results considering the change of the physical parameter (velocity) of the rock sample reflect the rock damage evolution more exactly. Consequently, the real-time evolution of physical parameters during hydraulic fracturing should be considered in numerical simulations. Rock damage evolution can be better captured using the offered modification of physical parameters. The present work provides theoretical guidance for hydraulic fracturing simulations to some extent.

scholarly journals Virtual Belt Algorithm for the Management of Isolated Autonomous Intersection

Algorithms ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 183
Author(s):  
Chentong Bian ◽  
Guodong Yin ◽  
Liwei Xu ◽  
Ning Zhang
Keyword(s):  
Numerical Simulations ◽  
Real Time ◽  
Online Algorithm ◽  
The Real ◽  
Traffic Efficiency ◽  
Simulation Results ◽  
Intersection Management ◽  
Real Time Application

To enhance traffic efficiency, in this paper, a novel virtual belt algorithm is proposed for the management of an isolated autonomous intersection. The proposed virtual belt algorithm consists of an offline algorithm and an online algorithm. Using the offline algorithm, the considered intersection can be modeled as several virtual belts. The online algorithm is designed for the real-time application of the virtual belt algorithm. Compared with the related algorithms, the main advantage of the proposed algorithm is that, there are several candidate trajectories for each approaching vehicle. Thus, there are more opportunities for an approaching vehicle to obtain a permission to pass an intersection, which is effective to improve traffic efficiency. The proposed algorithm is validated using numerical simulations conducted by Matlab and VISSIM. The simulation results show that the proposed algorithm is effective for autonomous intersection management.

A Micro-Cell Size Dependent Damage Law of Concrete

2015 ◽  
Vol 784 ◽  
pp. 200-208
Author(s):  
Shi Xue Liang ◽  
Xiao Dan Ren ◽  
Jie Li
Keyword(s):  
Numerical Simulations ◽  
Cell Size ◽  
Damage Evolution ◽  
Cell Analysis ◽  
Multi Scale ◽  
Size Dependent ◽  
Damage Law ◽  
Simulation Results

A micro-cell size dependent damage law is proposed by the multi-scale damage representation to remedy the mesh sensitivities involving in the numerical simulations. The homogenization based multi-scale damage representation is firstly introduced in obtaining the macro-damage evolution from micro-cell analysis. Then, the micro-cells with different sizes are generated and the corresponding simulations are given. Based on the simulation results, we define the micro-cell size dependent damage law. Finally, the accuracy and efficiency of the proposed damage law are verified by the notched beam simulation results.

STUDY OF THE GRAIN BOUNDARY MIGRATION IN A TRICRISTAL PURE ICE WITH BUBBLES

Anales AFA ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 47-51
Author(s):  
P.I. Achával ◽  
C. L. Di Prinzio
Keyword(s):  
Monte Carlo ◽  
Grain Boundary ◽  
Numerical Simulations ◽  
Triple Junction ◽  
Boundary Migration ◽  
Optical Microscope ◽  
Physical Parameters ◽  
Grain Boundary Migration

In this paper the migration of a grain triple junction in apure ice sample with bubbles at -5°C was studied for almost 3hs. This allowed tracking the progress of the Grain Boundary (BG) and its interaction with the bubbles. The evolution of the grain triple junction was recorded from successive photographs obtained witha LEICA® optical microscope. Simultaneously, numerical simulations were carried out using Monte Carlo to obtain some physical parameters characteristic of the BG migration on ice.

Modulation instability in nonlinear chiral fiber

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Demissie Jobir Gelmecha ◽  
Ram Sewak Singh
Keyword(s):  
Theoretical Model ◽  
Numerical Simulations ◽  
Pulse Propagation ◽  
Modulation Instability ◽  
Constitutive Relations ◽  
Gain Spectrum ◽  
Circularly Polarized ◽  
Left Handed ◽  
Simulation Results ◽  
The Difference

AbstractIn this paper, the rigorous derivations of generalized coupled chiral nonlinear Schrödinger equations (CCNLSEs) and their modulation instability analysis have been explored theoretically and computationally. With the consideration of Maxwell’s equations and Post’s constitutive relations, a generalized CCNLSE has been derived, which describes the evolution of left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) components propagating through single-core nonlinear chiral fiber. The analysis of modulation instability in nonlinear chiral fiber has been investigated starting from CCNLSEs. Based on a theoretical model and numerical simulations, the difference on the modulation instability gain spectrum in LCP and RCP components through chiral fiber has been analyzed by considering loss and chirality into account. The obtained simulation results have shown that the loss distorts the sidebands of the modulation instability gain spectrum, while chirality modulates the gain for LCP and RCP components in a different manner. This suggests that adjusting chirality strength may control the loss, and nonlinearity simultaneously provides stable modulated pulse propagation.

scholarly journals A modular framework to generate robust biped locomotion: from planning to control

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Mohammadreza Kasaei ◽  
Ali Ahmadi ◽  
Nuno Lau ◽  
Artur Pereira
Keyword(s):  
Numerical Simulations ◽  
Predictive Control ◽  
Biped Locomotion ◽  
Input Output ◽  
Dynamics Model ◽  
Biped Robots ◽  
The Core ◽  
Simulation Results ◽  
Reference Trajectories ◽  
Modular Framework

AbstractBiped robots are inherently unstable because of their complex kinematics as well as dynamics. Despite many research efforts in developing biped locomotion, the performance of biped locomotion is still far from the expectations. This paper proposes a model-based framework to generate stable biped locomotion. The core of this framework is an abstract dynamics model which is composed of three masses to consider the dynamics of stance leg, torso, and swing leg for minimizing the tracking problems. According to this dynamics model, we propose a modular walking reference trajectories planner which takes into account obstacles to plan all the references. Moreover, this dynamics model is used to formulate the controller as a Model Predictive Control (MPC) scheme which can consider some constraints in the states of the system, inputs, outputs, and also mixed input-output. The performance and the robustness of the proposed framework are validated by performing several numerical simulations using MATLAB. Moreover, the framework is deployed on a simulated torque-controlled humanoid to verify its performance and robustness. The simulation results show that the proposed framework is capable of generating biped locomotion robustly.

scholarly journals Measurement of Physical Parameters of Water Quality in Real-Time Based on Arduino

2021 ◽  
Vol 1751 ◽  
pp. 012067
Author(s):  
Junaidi ◽  
T M Putra ◽  
A Surtono ◽  
G A Puazi ◽  
S W Suciyati ◽  
...  
Keyword(s):  
Water Quality ◽  
Real Time ◽  
Physical Parameters

scholarly journals Spatiotemporal Patterns Formed by a Discrete Nutrient-Phytoplankton Model with Time Delay

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Feifan Zhang ◽  
Wenjiao Zhou ◽  
Lei Yao ◽  
Xuanwen Wu ◽  
Huayong Zhang
Keyword(s):  
Steady State ◽  
Time Delay ◽  
Numerical Simulations ◽  
Functional Response ◽  
Bifurcation Analysis ◽  
Discrete Model ◽  
Continuous Model ◽  
Spatiotemporal Patterns ◽  
Homogeneous Steady State ◽  
Simulation Results

In this research, a continuous nutrient-phytoplankton model with time delay and Michaelis–Menten functional response is discretized to a spatiotemporal discrete model. Around the homogeneous steady state of the discrete model, Neimark–Sacker bifurcation and Turing bifurcation analysis are investigated. Based on the bifurcation analysis, numerical simulations are carried out on the formation of spatiotemporal patterns. Simulation results show that the diffusion of phytoplankton and nutrients can induce the formation of Turing-like patterns, while time delay can also induce the formation of cloud-like pattern by Neimark–Sacker bifurcation. Compared with the results generated by the continuous model, more types of patterns are obtained and are compared with real observed patterns.

Accurate Simulation of the Four Modes of Post-Die Extrudate Shape Distortion

2021 ◽  
Vol 36 (1) ◽  
pp. 69-78
Author(s):  
M. Gupta
Keyword(s):  
Layer Structure ◽  
Die Design ◽  
Velocity Variation ◽  
Shape Distortion ◽  
Exit Velocity ◽  
Extrusion Die ◽  
Combined Flow ◽  
Extruded Product ◽  
Simulation Results ◽  
Extrudate Distortion

Abstract A combined flow, thermal and structural analysis is employed to simulate post-die extrudate distortion in different profile dies. All four factors which can cause extrudate distortion, namely, nonuniform exit velocity distribution, extrudate shrinkage, extrudate draw down, and deformed shape of the calibrator or sizer profile, are simulated. To analyze the effect of exit velocity variation on extrudate distortion, the parameterized geometry of a simple profile die is optimized using an extrusion die optimization software. The simulation results presented for a bi-layer profile die successfully demonstrate how gradually changing profile shape in successive calibrators/sizers can be used to simplify the die design for extrusion of complex profiles. The predicted extrudate shape and layer structure for the bi-layer die are found to accurately match with those in the extruded product.

scholarly journals Nanometre-Scale Visualization of Chemical Parameter Changes by T1-Weighted ODMR Imaging Using a Fluorescent Nanodiamond

Chemosensors ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 68
Author(s):  
Takahiro Fujisaku ◽  
Ryuji Igarashi ◽  
Masahiro Shirakawa
Keyword(s):  
Magnetic Resonance ◽  
Laser Pulse ◽  
Real Time ◽  
Physical Parameters ◽  
Biological Processes ◽  
Chemical Parameter ◽  
Ph Conditions ◽  
Optically Detected ◽  
Life Phenomena ◽  
Selection Of

The dynamics of physical parameters in cells is strongly related to life phenomena; thus, a method to monitor and visualize them on a single-organelle scale would be useful to reveal unknown biological processes. We demonstrate real-time nanometre-scale T1-weighted imaging using a fluorescent nanodiamond. We explored optically detected magnetic resonance (ODMR) contrast at various values of interval laser pulse (τ), showing that sufficient contrast is obtained by appropriate selection of τ. By this method, we visualized nanometre-scale pH changes using a functionalized nanodiamond whose T1 has a dependence on pH conditions.

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