Electrokinetic Research on the Dispersion Behavior of Nano-Ceria Particles in Concentrated Suspensions

2015 ◽  
Vol 645-646 ◽  
pp. 394-399
Author(s):  
Wei Gao ◽  
Qi Long Wei ◽  
Ling Ding ◽  
Xiao Yuan Li ◽  
Chao Wang ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Rheological Properties ◽  
Concentrated Suspensions ◽  
Tem Analysis ◽  
Concentrated Suspension ◽  
Original Solution ◽  
Multi Scale ◽  
Scale Method ◽  
Dispersion Behavior ◽  
Significant Difference

A multi-scale method was developed, which utilized intrinsic relationships among zeta potential of particles, rheological properties of suspensions and particle size distribution (PSD), to analyze dispersion behavior of nanoparticles in concentrated suspensions. It was found that PSD of a kind of nanoceria particles by dynamic light scattering (DLS) method in solution A with concentration 5 wt% accorded well with that by direct TEM analysis, which meant the particles had been dispersed well. However, there had a significant difference when the concentration was increased to 20 wt%. When particles concentration increased from 5 wt% to 20 wt%, zeta potential in solution A changed from-150 mV to-100 mV, while zeta potential in solution B changed from-35mV to-45 mV. Variations of zeta potential of particles accorded well with rheological properties of suspensions too, from phenomenological models. When the suspensions composed by solution A and the nanoparticles with concentration about 20 wt% was diluted with its original solution to 5 wt%, the PSD of nanoceria could be measured indirectly, which accorded well with both that of a suspension prepared directly with near concentration and that from TEM images. Then a method to measure PSD of nanoparticles in concentrated suspension was brought forward.

The zeta potential of kaolin suspensions measured by electrophoresis and electroacoustics

2007 ◽  
Vol 61 (2) ◽  
Author(s):  
R. Greenwood ◽  
B. Lapčíková ◽  
M. Surýnek ◽  
K. Waters ◽  
L. Lapčík
Keyword(s):  
Zeta Potential ◽  
Isoelectric Point ◽  
Anionic Surfactant ◽  
Sodium Dodecyl ◽  
Isomorphic Substitution ◽  
Concentrated Suspensions ◽  
Concentrated Suspension ◽  
Zeta Potentials ◽  
Maximum Value ◽  
Triton X

AbstractThe zeta potentials of kaolin dilute and concentrated suspensions were monitored using the techniques of electrophoresis and electroacoustics, respectively. The effect of addition of salt (KCl), a polymer material (Triton X-100), and an anionic surfactant (sodium dodecyl sulphate, SDS) on the suspension properties was investigated by electrophoresis. Electroacoustics was employed for the measurement of zeta potentials for the highest possible kaolin content in suspension and the effect of dilution. The effect of aging of a freshly prepared sample and kaolin isoelectric point was also studied. Using both techniques it was noted that there was no isoelectric point, just a maximum value in the magnitude of the kaolin suspension zeta potential. These maxima were observed also in the presence of Triton X-100 and SDS. An increase of the concentration of KCl and SDS in suspension shifted the maxima towards more acidic values, while in the presence of Triton X-100 the position of the zeta potential maxima remained constant. Electroacoustic techniques revealed that a freshly prepared concentrated suspension requires about six hours to equilibrate to achieve a steady zeta potential. Diluting the concentrated suspensions led to decrease of the zeta potential as ions bound to the surface desorbed and screened the surface charge. The zeta potential maxima remained unchanged even after heating the powder in an oven at 200°C (to remove any organic material) thereby suggesting that the most likely explanation for the maxima is isomorphic substitution.

Utilization of a Phosphate Ester as a Dispersant for SiAlON Based Ceramics

2007 ◽  
Vol 554 ◽  
pp. 71-77 ◽  
Author(s):  
A. Ceylan ◽  
E. Suvaci ◽  
Hasan Mandal
Keyword(s):  
Zeta Potential ◽  
Rheological Properties ◽  
Powder Mixture ◽  
Sodium Tripolyphosphate ◽  
Phosphate Ester ◽  
Aqueous Dispersions ◽  
Aqueous Suspensions ◽  
Dispersion Behavior

Aqueous dispersions of SiAlON forming powders (Si3N4, AlN and Y2O3) were obtained. Dispersibility of powders was found to be improved by addition of sodium tripolyphosphate. Stable aqueous suspensions of SiAlON forming powders were prepared by using a phosphate ester, sodium tripolyphosphate (STPP, Na5P3O10). Effect of the STPP on rheological properties of the powder mixture was investigated by zeta potential measurements, sedimentation and milling studies. It has been shown that addition of the STPP to the aqueous SiAlON forming powder mixture improves the dispersion behavior significantly. These results suggest that STPP can be utilized as a dispersant in such ceramic systems.

scholarly journals Detection of Myocardial Infarction Using ECG and Multi-Scale Feature Concatenate

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1906
Author(s):  
Jia-Zheng Jian ◽  
Tzong-Rong Ger ◽  
Han-Hua Lai ◽  
Chi-Ming Ku ◽  
Chiung-An Chen ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Network Structure ◽  
Class Imbalance ◽  
Class Imbalance Problem ◽  
Multi Scale ◽  
Imbalance Problem ◽  
Average Accuracy ◽  
Significant Difference ◽  
Electrocardiogram Ecg

Diverse computer-aided diagnosis systems based on convolutional neural networks were applied to automate the detection of myocardial infarction (MI) found in electrocardiogram (ECG) for early diagnosis and prevention. However, issues, particularly overfitting and underfitting, were not being taken into account. In other words, it is unclear whether the network structure is too simple or complex. Toward this end, the proposed models were developed by starting with the simplest structure: a multi-lead features-concatenate narrow network (N-Net) in which only two convolutional layers were included in each lead branch. Additionally, multi-scale features-concatenate networks (MSN-Net) were also implemented where larger features were being extracted through pooling the signals. The best structure was obtained via tuning both the number of filters in the convolutional layers and the number of inputting signal scales. As a result, the N-Net reached a 95.76% accuracy in the MI detection task, whereas the MSN-Net reached an accuracy of 61.82% in the MI locating task. Both networks give a higher average accuracy and a significant difference of p < 0.001 evaluated by the U test compared with the state-of-the-art. The models are also smaller in size thus are suitable to fit in wearable devices for offline monitoring. In conclusion, testing throughout the simple and complex network structure is indispensable. However, the way of dealing with the class imbalance problem and the quality of the extracted features are yet to be discussed.

scholarly journals Temperature Resistance of Mo3Si: Phase Stability, Microhardness, and Creep Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 564 ◽  
Author(s):  
Olha Kauss ◽  
Susanne Obert ◽  
Iurii Bogomol ◽  
Thomas Wablat ◽  
Nils Siemensmeyer ◽  
...  
Keyword(s):  
Power Law ◽  
Phase Stability ◽  
Gas Turbines ◽  
Constitutive Models ◽  
Creep Properties ◽  
Multi Scale ◽  
Scale Modeling ◽  
Significant Difference ◽  
Before And After ◽  
Multi Phase

Mo-Si-B alloys are one of the most promising candidates to substitute Ni based superalloys in gas turbines. The optimization of their composition can be achieved more effectively using multi-scale modeling of materials behavior and structural analysis of components for understanding, predicting, and screening properties of new alloys. Nevertheless, this approach is dependent on data on the properties of the single phases in these alloys. The focus of this investigation is Mo3Si, one of the phases in typical Mo-Si-B alloys. The effect of 100 h annealing at 1600 °C on phase stability and microhardness of its three near-stoichiometric compositions—Mo-23Si, Mo-24Si and Mo-25Si (at %)—is reported. While Mo-23Si specimen consist only of Mo3Si before and after annealing, Mo-24Si and Mo-25Si comprise Mo5Si3 and Mo3Si before annealing. The latter is then increased by the annealing. No significant difference in microhardness was detected between the different compositions as well as after annealing. The creep properties of Mo3Si are described at 1093 °C and 1300 °C at varying stress levels as well as at 300 MPa and temperatures between 1050 °C and 1350 °C. Three constitutive models were used for regression of experimental results—(i) power law with a constant creep exponent, (ii) stress range dependent law, and (iii) power law with a temperature-dependent creep exponent. It is confirmed that Mo3Si has a higher creep resistance than Moss and multi-phase Mo-Si-B alloys, but a lower creep strength as compared to Mo5SiB2.

Electroacoustic Study of n-Hexadecane/Water Emulsions

2001 ◽  
Vol 54 (8) ◽  
pp. 503 ◽  
Author(s):  
Linggen Kong ◽  
James K. Beattie ◽  
Robert J. Hunter
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Volume Fraction ◽  
Sodium Dodecyl ◽  
Surfactant Solution ◽  
Minimum Size ◽  
Water Mixture ◽  
Concentrated Suspensions ◽  
Minimum Concentration ◽  
Median Diameter

n-Hexadecane-in-water emulsions were investigated by electroacoustics using a prototype of an AcoustoSizer-II apparatus. The emulsions were formed by passing the stirred oil/water mixture through a homogenizer in the presence of sodium dodecyl sulfate (SDS) at natural pH (6–7). With increasing oil-volume fraction, the particle size increased linearly after 5 and also after 20 passages through the homogenizer, suggesting that surface energy was determining particle size. For systems in which the surfactant concentration was limited, the particle size after 20 passages approached the value dictated by the SDS concentration. With ample surfactant present, the median diameter was a linear function of the inverse of the total energy input as measured by the number of passes. There was, however, a limit to the amount of size reduction that could be achieved in the homogenizer, and the minimum size was smaller at smaller volume fractions. Dilution of the emulsion with a surfactant solution of the same composition as the water phase had a negligible effect on the particle size and changed the zeta potential only slightly. This confirms results from previous work and validates the equations used to determine the particle size and zeta potential in concentrated suspensions. The minimum concentration of SDS that could prevent the emulsion from coalescing for the system with 6% by volume oil was 3 mM. For this dilute emulsion, the particle size decreased regularly with an increase in SDS concentration, but the magnitude of the zeta potential went through a strong maximum at intermediate surfactant concentrations.

Wavelet Multi-Scale Solution for Deflection of Thin Rectangular Plates under Temperature

2012 ◽  
Vol 166-169 ◽  
pp. 2871-2875
Author(s):  
Yan Chang Wang ◽  
Ke Liang Ren ◽  
Yan Dong ◽  
Ming Guang Wu
Keyword(s):  
Differential Equations ◽  
Rectangular Plate ◽  
Thermal Environment ◽  
Operational Matrix ◽  
Rectangular Plates ◽  
Thin Rectangular Plate ◽  
Multi Scale ◽  
Scale Method ◽  
The Matrix ◽  
Operational Matrix Of Integration

To consider the deformation of thin rectangular plate under temperature. In this paper, the wavelet multi-scale method was used to solve the thin plate governing differential equations with four different initial or boundary conditions. An operational matrix of integration based on the wavelet was established and the procedure for applying the matrix to solve the differential equations was formulated, and got the deflection of thin rectangular plates under temperature. The result provides a theoretical reference for solving thin rectangular plate deflection in thermal environment using multi-scale approach.

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