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.

scholarly journals Effect of nano-solid particles on the mechanical properties of shear thickening fluid (STF) and STF-Kevlar composite fabric

2021 ◽  
Vol 16 ◽  
pp. 155892502110448
Author(s):  
Mingmei Zhao ◽  
Jinqiu Zhang ◽  
Zhizhao Peng ◽  
Jian Zhang
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Tensile Force ◽  
Shear Thickening ◽  
Solid Particles ◽  
Time Range ◽  
Shear Thickening Fluid ◽  
Pull Out ◽  
Diamond Particles

To analyze the effect of nano-solid particles on the mechanical properties of shear thickening fluid (STF) and its Kevlar composite fabric. In this study, nano-silica and polyethylene glycol (PEG 200) were used as dispersed and continuous phases. Nano-graphite and nano-diamond particles were used as additives to prepare STF and Kevlar composite fabric. Study the friction characteristics and rheological characteristics of STF at different temperatures. Explore the STF’s mechanical response under transient high-speed impact conditions through the split Hopkinson pressure bar experiment. The mechanical properties of STF-Kevlar fabric are studied through yarn pull-out test and burst experiments. The experimental results show that the intermolecular repulsive force of STF is enhanced under a high-temperature environment, and shear thickening effect is reduced. Nano-diamond particles strengthen the contact coupling force and contact probability between the particle clusters, so that the maximum viscosity of the system reaches 1679 Pa s, the thickening ratio reaches 318 times, and the rheological properties of the shear thickening fluid are improved. The results of the SHPB experiment show that the STF can complete a dynamic response within a 50–75 µs time range, and the maximum stress can reach 78 MPa. The bullet’s incident kinetic energy is not only transformed into thermal energy and phase change energy of solid-liquid conversion, but also into frictional energy between particles. The mechanical experiments of STF-Kevlar composite fabrics show that the tensile force value of STF5-Kevlar is the largest (10.3 N/13.5 N), and the tensile force of neat Kevlar was the smallest (4.3 N/4.9 N). The maximum bearing capacity (0.3 kN) and absorption energy (51.8 J) of Neat Kevlar are less than those of STF1-Kevlar (3.2 kN, 116.7 J) and STF3-Kevlar (1.9 kN, 88.2 J), and STF5-Kevlar (4.7 kN, 143.3 J). Fabric’s failure mode is converted from partial yarn extraction to overall deformation and rupture of the fabric. Therefore, by changing the solid additives’ parameters, the STF and the composite fabric’s mechanical properties can be effectively controlled, which provides a reference for preparing the STF and fabric composite materials.

scholarly journals Effectively enhanced structural stability and electrochemical properties of LiNi0.5Mn1.5O4cathode materialsviapoly-(3,4-ethylenedioxythiophene)-in situcoated for high voltage Li-ion batteries

RSC Advances ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 3081-3091 ◽  
Author(s):  
JinFeng Liu ◽  
YuFang Chen ◽  
Jing Xu ◽  
WeiWei Sun ◽  
ChunMan Zheng ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrochemical Properties ◽  
Structural Stability ◽  
High Voltage ◽  
Structure Stability ◽  
Li Ion Batteries ◽  
Li Ion

PEDOT coating on LNMO surface effectively improves it's the crystal structure stability and electrochemical properties.

Shear Thickening Behaviour of Composite Propellant Suspension under Oscillatory Shear

2016 ◽  
Vol 66 (3) ◽  
pp. 222 ◽  
Author(s):  
D. Singh ◽  
G. Dombe ◽  
C. Bhongale ◽  
P. P. Singh ◽  
Mehilal Maurya ◽  
...  
Keyword(s):  
Strain Amplitude ◽  
Loss Modulus ◽  
Shear Thickening ◽  
Rheological Behaviour ◽  
Complex Viscosity ◽  
Solid Particles ◽  
Dynamic Moduli ◽  
Composite Propellant ◽  
Plateau Region ◽  
Temperature Constant

Composite propellant suspensions consist of highly filled polymeric system wherein solid particles of different sizes and shapes are dispersed in a polymeric matrix. The rheological behaviour of a propellant suspension is characterised by viscoplasticity and shear rate and time dependant viscosity. The behaviour of composite propellant suspension has been studied under amplitude sweep test where tests were performed by continuously varying strain amplitude (strain in %, γ) by keeping the frequency and temperature constant and results are plotted in terms of log γ (strain amplitude) vs logGʹ and logGʺ (Storage modulus and loss modulus, respectively). It is clear from amplitude sweep test that dynamic moduli and complex viscosity show marked increase at critical strain amplitude after a plateau region, infering a shear thickening behaviour.

A Hierarchical Integration of Person-Centered Comorbidity Models: Structure, Stability, and Transition Over Time

2017 ◽  
Vol 5 (4) ◽  
pp. 595-612 ◽  
Author(s):  
Hyunsik Kim ◽  
Nicholas R. Eaton
Keyword(s):  
Structural Stability ◽  
Group Structure ◽  
Latent Transition Analysis ◽  
Structure Stability ◽  
Transition Analysis ◽  
Empirically Supported ◽  
Diagnostic Time ◽  
Latent Transition ◽  
Nationally Representative ◽  
Over Time

Person-centered analyses of mental disorder comorbidity typically identify a single optimal latent group structure. We took an alternate approach, modeling every estimable comorbidity class model in a nationally representative sample ( N = 34,653) and integrating them into a single overarching hierarchy, providing a full multilevel accounting of various person-centered comorbidity structures. We then investigated the structural stability of this hierarchy across two waves of data collection, and the stability of, and transition between, comorbidity classes over time using latent transition analysis. Findings suggested that comorbidity classes were structured into an interpretable hierarchy. Evidence for robust structural stability of the hierarchy over time was found, regardless of assessment time points and diagnostic time frames used. Latent transition analysis provided evidence for both continuity and change of comorbidity group membership. We discuss how person- and variable-centered models provide complementary perspectives toward empirically supported classification.

Correlation between stability, structural indicators and organic matter in soils used for growing malting barley

2013 ◽  
Vol 61 (3) ◽  
pp. 237-246 ◽  
Author(s):  
J. Prieto Méndez ◽  
O. Acevedo Sandoval ◽  
F. Prieto García
Keyword(s):  
Organic Matter ◽  
Size Distribution ◽  
Structural Stability ◽  
Close Association ◽  
Negative Relationship ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Simple Random Sampling ◽  
Structure Stability ◽  
Malting Barley

Soil structure stability depends on several factors and its assessment is conducted using different methods and prediction indices. One of the indicators is soil organic matter (SOM), since this helps to keep mineral particles together against destabilizing forces such as wetting and raindrop impact. However, previous studies have emphasized the relationship between aggregate stability and SOM content without considering its type or quality. Therefore, in this study the association between the quality and content of SOM and the structural stability of the surface layer was evaluated in three soils used for growing malting barley in the southern part of Hidalgo State, Mexico. With simple random sampling nine observation points were selected in each soil, where samples were taken in order to determine the stable aggregate size distribution, particle size distribution, content and fractionation of SOM, and the prediction indices of surface sealing and crusting derived from these characteristics. The soils showed low structural stability (except in Apan), as shown by the percentage runoff recorded in the field. There was a close association between the size (from 4 to 2 mm and <0.25 mm) of water-stable aggregates and the different fractions of SOM, while the fulvic acid (FA) fraction had a negative relationship with smaller aggregates (R = −0.84). Finally, it was found that only the FAO crusting index was able to predict the structural stability level in the soil.

Thixotropic Strength and Thixotropic Criteria in Semi-Solid Processing

2008 ◽  
Vol 141-143 ◽  
pp. 319-323 ◽  
Author(s):  
W.C. Keung ◽  
Y.F. Lee ◽  
Wei Wei Shan ◽  
Shou Jing Luo
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Shape Factor ◽  
Shear Thickening ◽  
Solid Material ◽  
Solid Content ◽  
Solid Particles ◽  
Thixotropic Behavior ◽  
Semi Solid ◽  
Constant Shear Rate

Thixotropy is essential to semi-solid processing, and because of it the semi-solid material is characterized by ‘shear shinning’. Here, thixotropic strength and thixotropic criteria in semi-solid processing are put forward based on related theories and experiments, and thixotropic mechanism and its influencing factors are also investigated. The results are as follows: 1) the term of thixotropic strength means that with constant shear rate at semi-solid temperature, the semi-solid body begins to flow when the shear stress reach a certain value. This value of shear stress is defined as the thixotropic strength; 2) Thixotropic behavior happens with ‘shear thinning’ because of the deagglomeration of solid particles, while ‘shear thickening’ happens because of the agglomeration at the same time. With increasing shear time, the shear stress increases first and then decreases rapidly to reach a stable value. 3) There are three important factors that influence ‘thixotropic strength’: temperature (hence solid content), initial microstructure (including size, shape factor and uniformity of solid particles) and shear rate.

First-Principles Calculation of Carbides in Niobium Microalloyed Medium and High Carbon Steels

2012 ◽  
Vol 468-471 ◽  
pp. 1798-1801
Author(s):  
Dong Wang ◽  
Jian Chun Cao ◽  
Xiao Long Zhou ◽  
Dong Wei Zhao ◽  
Lei Deng
Keyword(s):  
Structural Stability ◽  
Structure Type ◽  
Carbon Steels ◽  
Binding Energies ◽  
First Principles Calculation ◽  
Structure Stability ◽  
Low Carbon ◽  
High Carbon ◽  
Plane Wave Method ◽  
The Difference

The binding energies, formation energies and DOS (density of state) of several carbides(Fe3C, Fe2C, Fe5C2, NbC) in Nb micro-alloyed steels are investigated using the first-principle pseudo potential plane-wave method. The results show that the structure type with the strongest alloying ability and the highest structure stability is NbC with fcc structure. After compared the DOS of these different structure types, the results show that the discrepancy in structural stability of carbides can be attributed to the difference in the bonding electron numbers at Feimi level. The less the valence electrons at Feimi level are, the better the structural stability of carbides. Therefore, the theory predicts that the existence form of Nb in medium and high carbon steels are the same as low carbon steels. Nb is still the effective alloying element in medium and high carbon steels.

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