scholarly journals Time-Varying Hydraulic Gradient Model of Paste-Like Tailings in Long-Distance Pipeline Transportation

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Li Yang ◽  
Shuai Li ◽  
Xin-min Wang
Keyword(s):  
High Precision ◽  
Hydraulic Gradient ◽  
Time Varying ◽  
Pipeline Transportation ◽  
Shear Tests ◽  
Long Distance ◽  
Bingham Plastic ◽  
Gradient Model ◽  
Plastic Fluid ◽  
Computational Errors

Paste-like tailings slurry (PTLS) is always simplified as a Bingham plastic fluid, leading to excessive computational errors in the calculation of the hydraulic gradient. In the case of paste-like tailings in long-distance pipeline transportation, to explore a high-precision and reliable hydraulic gradient formula, the rheological behavior of paste-like tailings slurry was analyzed, a time-varying hydraulic gradient model was constructed, and a series of laboratory shear tests were conducted. The results indicate that the PTLS shows noticeable shear-thinning characteristics in constant shear tests; the calculated hydraulic gradient declined by about 56%, from 4.44 MPa·km−1 to 1.95 MPa·km−1 within 253 s, and remained constant for the next four hours during the pipeline transportation. Comparing with the balance hydraulic gradient obtained in a semi-industrial loop test, the computational errors of those calculated by using the time-varying hydraulic gradient model, Jinchuan formula, and Shanxi formula are 15%, 78%, and 130%, respectively. Therefore, our model is a feasible and high-precision solution for the calculation of the hydraulic gradient of paste-like tailings in long-distance pipeline transportation.

A hydraulic gradient model of paste-like crude tailings backfill slurry transported by a pipeline system

2016 ◽  
Vol 75 (14) ◽  
Author(s):  
Qiusong Chen ◽  
Qinli Zhang ◽  
Xinmin Wang ◽  
Chongchun Xiao ◽  
Qing Hu
Keyword(s):  
Hydraulic Gradient ◽  
Pipeline System ◽  
Gradient Model

Synthesis and Properties of Fe3O4 Ferrofluids with Narrow Particle Size Distribution

2011 ◽  
Vol 694 ◽  
pp. 575-579
Author(s):  
Jian Hui Zhang ◽  
Hai Bo Sun
Keyword(s):  
Magnetic Particles ◽  
Particle Diameter ◽  
Free Form ◽  
Narrow Particle Size Distribution ◽  
Particle Sizes ◽  
Bingham Plastic ◽  
Plastic Fluid ◽  
Form Model ◽  
The Mean ◽  
Inference Theory

Fe3O4 ferrofluids with uniform magnetic particles were prepared via improved chemical coprecipation technique. A narrow distribution of 8.6-10.8 nm particle sizes was obtained from the magnetization curve using the free-form-model based on Bayesian inference theory. The mean particle diameter about 9.8 nm is consistent with the XRD and SEM results. The hydrodynamic properties of ferrofluids were investigated with different applied magnetic field and shear rate. The experimental results show that diluted ferrofluid and concentrated ferrofluid are Newtonian-fluid and Bingham-plastic fluid, respectively.

scholarly journals Long-Distance Time Transfer in Optical Fiber Networks Using a Cascaded Taming Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ding Chen ◽  
Jiangning Xu ◽  
Yifeng Liang ◽  
Shan Jiang ◽  
Hongyang He
Keyword(s):  
Optical Fiber ◽  
High Precision ◽  
Wavelength Division Multiplexing ◽  
Time Synchronization ◽  
Atomic Clock ◽  
Process Time ◽  
Long Distance ◽  
Time Service ◽  
Time Frequency ◽  
Fiber Link

In order to meet the time service needs of high-precision, long-distance, and multinode optical network, this paper proposes a new time synchronization solution, which combines the wavelength division multiplexing (WDM) technology with cascaded taming clock technology. The WDM technology is used for time synchronization between each pair of master-slave nodes. In the system, there are two wavelengths on the fiber link between the master node and the slave node for transmitting signals. 1 plus per second (PPS) signal, time code signal, and 10 MHz signal are, respectively, and successively, sent to the optical fiber link. By solving the one-way delay through analysis of error contribution and link characteristics of the time transmission process, time synchronization of the master-slave nodes pair is achieved. Furthermore, the authors adopt cascaded taming clock technology to ensure accurate time synchronization of each node. A 700 km long-distance time-frequency synchronization system is constructed in the laboratory. The system uses a cesium atomic clock as the reference clock source and transmits the signals through 8 small rubidium atomic clocks (RB clocks) hierarchically. Results from the experiment show that the long-term time stability is 47.5 ps/104 s. The system’s structural characteristics and the experiment results meet the requirements to allow practical use of high-precision time synchronization in networks. This proposed solution can be applied in various civil, commercial, and military fields.

scholarly journals Development of a distributed hybrid seismic–electrical data acquisition system based on the Narrowband Internet of Things (NB-IoT) technology

2019 ◽  
Vol 8 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Wenhao Li ◽  
Qisheng Zhang ◽  
Qimao Zhang ◽  
Feng Guo ◽  
Shuaiqing Qiao ◽  
...  
Keyword(s):  
Internet Of Things ◽  
Data Acquisition ◽  
High Precision ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Geophysical Prospecting ◽  
Long Distance ◽  
Data Acquisition Board ◽  
Acquisition Processes ◽  
Electrical Data

Abstract. The ambiguity of geophysical inversions, which is based on a single geophysical method, is a long-standing problem in geophysical exploration. Therefore, multi-method geophysical prospecting has become a popular topic. In multi-method geophysical prospecting, the joint inversion of seismic and electric data has been extensively researched for decades. However, the methods used for hybrid seismic–electric data acquisition that form the base for multi-method geophysical prospecting techniques have not yet been explored in detail. In this work, we developed a distributed, high-precision, hybrid seismic–electrical data acquisition system using advanced Narrowband Internet of Things (NB-IoT) technology. The system was equipped with a hybrid data acquisition board, a high-performance embedded motherboard based on field-programmable gate array, an advanced RISC machine, and host software. The data acquisition board used an ADS1278 24 bit analog-to-digital converter and FPGA-based digital filtering techniques to perform high-precision data acquisition. The equivalent input noise of the data acquisition board was only 0.5 µV with a sampling rate of 1000 samples per second and front-end gain of 40 dB. The multiple data acquisition stations of our system were synchronized using oven-controlled crystal oscillators and global positioning system technologies. Consequently, the clock frequency error of the system was less than 10−9 Hz at 1 Hz after calibration, and the synchronization accuracy of the data acquisition stations was ±200 ns. The use of sophisticated NB-IoT technologies allowed the long-distance wireless communication between the control center and the data acquisition stations. In validation experiments, it was found that our system was operationally stable and reliable, produced highly accurate data, and it was functionally flexible and convenient. Furthermore, using this system, it is also possible to monitor the real-time quality of data acquisition processes. We believe that the results obtained in this study will drive the advancement of prospective integrated seismic–electrical technologies and promote the use of IoT technologies in geophysical instrumentation.

scholarly journals Airborne Integrated Navigation System Based on SINS/GPS/TAN/EOAN

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Junjun Tang ◽  
Peijuan Li
Keyword(s):  
High Precision ◽  
Navigation System ◽  
Integrated Navigation ◽  
Long Distance ◽  
Integrated Navigation System ◽  
Long Time ◽  
Federated Kalman Filter ◽  
Entropy Weighted ◽  
Navigation Errors ◽  
Navigation Information

Considering the drawbacks that GPS signal is susceptible to obstacles and TAN becomes useless in some area when without any terrain data or with a featureless terrain field, to realize long-distance and high-precision navigation, a navigation system based on SINS/GPS/TAN/EOAN is presented. When GPS signal is available, GPS is used to correct errors of SINS; when GPS is unavailable, a terrain selection method based on the entropy weighted gray relational decision-making method is use to distinguish terrain into matchable areas and unmatchable areas; then, for the matchable areas, TAN is used to correct errors of SINS, for the unmatchable areas, EOAN is used to correct errors of SINS. The principles of SINS, GPS, TAN, and EOAN are analyzed, the mathematic models of SINS/GPS, SINS/TAN, and SINS/EOAN are constructed, and finally the federated Kalman filter is used to fuse navigation information. Simulation results show that the trajectory of SINS/GPS/TAN/EOAN is close to the ideal one in both matchable area or unmatchable area and whose navigation errors are obviously reduced, which is important for the realization of long-time and high-precision positioning.

scholarly journals Effect of Anionic Polyacrylamide on the Structural Stability of Thickened Tailings Slurry in Pipeline Transportation

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Shi Wang ◽  
Shuai Li ◽  
Jian-chun Qin ◽  
Guang-zhe Xiao ◽  
Guo-chun Yang ◽  
...  
Keyword(s):  
Structural Stability ◽  
Shear Thickening ◽  
Solid Particles ◽  
Structure Stability ◽  
Pipeline Transportation ◽  
Shear Tests ◽  
Hindered Settling ◽  
Fine Tailings ◽  
Thickened Tailings ◽  
Anionic Polyacrylamide

Taking the superfine tailings slurry (STS), fine tailings slurry (FTS), and unclassified tailings slurry (UTS) of a gold mine as examples, a series of laboratory shear tests were conducted to investigate the effect of anionic polyacrylamide (APAM) on the structural stability of the thickened tailings slurry in pipeline transportation. Experimental results showed that the FTS and UTS had shear-thinning and shear-thickening characteristics in the constant shear tests, respectively. After addition of APAM, when the shear rate was 30 s−1, standard deviations of apparent viscosity of FTS, UTS, and STS were 66.67%, 61.40%, and 35.33% lower, respectively. APAM enhances the strength of the flocculent structures, inhibits the hindered settling of the coarse-particle tailings, improves the structure stability of the solid particles on the structural plane, and assists pipeline transportation of the thickened tailings slurry.

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