scholarly journals DEPENDENCE OF THE STABILITY OF THE FERROELECTRIC PHASE OF POTASSIUM NITRATE IN A COMPOSITE WITH BARIUM TITANATE ON THE VOLUME AND SIZE OF INCLUSION PARTICLES

2020 ◽  
pp. 30-36
Author(s):  
NIKITA SERGEEVICH KONTES ◽  
◽  
ELENA VLADIMIROVNA STUKOVA ◽  
IRINA ANATOLYEVNA GOLUBEVA ◽  
OKSANA VASILIEVNA ZOTOVA ◽  
...  
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Barium Titanate ◽  
Ferroelectric Phase ◽  
Volume Fraction ◽  
Potassium Nitrate ◽  
Ferroelectric State ◽  
The Stability

The results of a study of composites (KNO3) 1 -x /(BaTiO3)x (x = 0.1 and 0.2) are presented. It is shown that the stability of the ferroelectric state of potassium nitrate increases with an increase in the volume fraction of inclusions. It was found that the stability of the ferroelectric phase of potassium nitrate in the composite is also influenced by the particle size of the inclusions. It was revealed that the values of the dielectric constant in the region of the ferroelectric phase increase with an increase in the particle size of the inclusions.

scholarly journals The effect of barium titanate admixture on the stability of potassium nitrate ferroelectric phase in (1–x)KNO3 + (x)BaTiO3 composites

2015 ◽  
Vol 1 (3) ◽  
pp. 229-234
Author(s):  
Olga A. Alekseeva ◽  
Alexander A. Naberezhnov ◽  
Elena V. Stukova ◽  
Vadim I. Popkov
Keyword(s):  
Barium Titanate ◽  
Ferroelectric Phase ◽  
Potassium Nitrate ◽  
The Stability

Dielectric Behavior of Barium Titanate/Carbon Fibers Composites

2017 ◽  
Vol 898 ◽  
pp. 2101-2106
Author(s):  
Zhong Yang Wang ◽  
Xin Yan Li ◽  
Run Hua Fan ◽  
Pei Tao Xie ◽  
Kai Sun ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Carbon Fibers ◽  
Percolation Theory ◽  
High Dielectric Constant ◽  
Volume Fraction ◽  
Dielectric Behavior ◽  
Lower Volume Fraction ◽  
Lower Volume ◽  
High Dielectric

Conductor–insulator composites have been extensive researched for high dielectric constant. Most of them concentrated on metal polymers or metal ceramics. Barium titanate–carbon fibers composites were prepared by using a solid state reaction process with carbon fibers contents ranging from7 vol% to 23 vol%. Due to the high-aspect-ratio of carbon fiber, it was easy to produce a conducting network at much lower volume fraction. FESEM images illustrated that the carbon fibers influenced the densification and microstructure of the ceramics. Besides, addition of carbon fibers led to increase in dielectric permittivity, also had effects on the dielectric loss and ac conductivity. The dielectric and conductivity properties as a function of carbon fibers volume fraction were explained by the percolation theory.

scholarly journals Stabilization of the NOP ferroelectric phase in potassium nitrate–barium titanate ferroelectric composites

2017 ◽  
Vol 3 (3) ◽  
pp. 187-191
Author(s):  
Olga A. Alekseeva ◽  
Aleksandr А. Naberezhnov ◽  
Elena V. Stukova ◽  
Valeriy G. Simkin
Keyword(s):  
Barium Titanate ◽  
Ferroelectric Phase ◽  
Potassium Nitrate

scholarly journals Влияние концентрации La на кинетику индуцированного фазового перехода в прозрачной керамике PbMg-=SUB=-1/3-=/SUB=-Nb-=SUB=-2/3-=/SUB=-O-=SUB=-3-=/SUB=--25PbTiO-=SUB=-3-=/SUB=-

2020 ◽  
Vol 62 (4) ◽  
pp. 584
Author(s):  
Л.С. Камзина ◽  
G. Li
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Electric Fields ◽  
Optical Transmission ◽  
Ferroelectric Phase ◽  
Sharp Decrease ◽  
Polar Regions ◽  
Transparent Ceramics ◽  
The Stability ◽  
Over Time

The effect of La concentration on the kinetic nature of the induced phase transition in PbMg1/3Nb2/3O3–25PbTiO3 ferroceramics was studied. At temperatures below the Vogel-Fulcher temperature, the time-dependent changes in the dielectric constant and optical transmission in electric fields are studied 0 <E <6 kV / cm. It was found that in an electric field in La-containing transparent ceramics, a sharp decrease in the dielectric constant and optical transmission occurs over time, indicating an induced phase transition and an increase in the fraction of the ferroelectric phase. It has been shown that in undoped La ceramics the changes in the dielectric constant at the same fields are much smaller. It was found that the stability of the induced phase depends on the La concentration: the higher the concentration, the lower the stability. The results obtained are explained by both a varying degree of diffuse of the phase transition and different sizes of polar regions, which depend on the La concentration.

Preparation of Alumina from NaOH-NaAlO2-Na2CrO4-H2O Solutions by Carbonization Process

2013 ◽  
Vol 455 ◽  
pp. 48-53
Author(s):  
Guang Ye Wei ◽  
Jing Kui Qu ◽  
Pei Yu Zhang ◽  
Qiang Guo ◽  
Yu Dong Zheng ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Removal Efficiency ◽  
Volume Fraction ◽  
Seed Particle ◽  
Carbonization Process ◽  
Stability Of Solution ◽  
Alkali Solutions ◽  
The Stability ◽  
Small Content

Alumina was prepared from NaOH-NaAlO2-Na2CrO4-H2O solutions (chromate alkali solutions) by carbonization process. The effect of seed ratio, carbon dioxide (CO2) volume fraction, reaction temperature, and initial sodium hydroxide (NaOH) concentration on the removal efficiency of Al was investigated in detail. High removal efficiency of Al was obtained following the increase of CO2volume fraction and temperature. While, initial NaOH concentration increases the stability of solution and reduces the removal efficiency of Al. Bayerite (Al (OH)3) with small content of Cr (VI) and Na2O was obtained from alkali metal chromate solutions at 50 °C with no seed. Particle size of bayerite (d50) was about 24 μm. Al2O3was obtained after calcination at 1050 °C for 1.5 h.

Development of Dielectric Elastomer Actuators - Part II: Preparation of the High Dielectric Constant Film Actuators Containing BaTiO3 Particles

2012 ◽  
Vol 557-559 ◽  
pp. 1869-1874 ◽  
Author(s):  
Takeshi Fukuda ◽  
Zhi Wei Luo ◽  
Aya Ito
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Volume Fraction ◽  
Breakdown Strength ◽  
Electrical Breakdown ◽  
Dielectric Elastomer ◽  
Dielectric Elastomer Actuators ◽  
Electrical Breakdown Strength ◽  
High Dielectric

Dielectric elastomer actuators with high dielectric constant and flexibility were prepared. These actuators were fabricated by the composite of barium titanate (BaTiO3) and polyester-type thermosetting polyurethane (TSU), which was molecularly-designed to become less hard segment content. In this study, the effects of particle size, volume fraction and manufacturing method of BaTiO3 were investigated. In addition, the mechanically-stretched effect in composites was also evaluated. It turned out that the electrical breakdown strength increased with the increase of particle size of BaTiO3 and in volume fraction as well as the use of BaTiO3 synthesized by the oxalate method. In addition, prestrain of composites also raised the electrical breakdown strength. However, the addition of BaTiO3 to polyurethane didn’t contribute to the actuation under a lower electric field.

scholarly journals Barium Titanate Nanoparticles Formed by Chlorine-Free Ambient Condition Sol Process Using Tetrabutylammonium Hydroxide

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Wooje Han ◽  
Byungwook Yoo ◽  
Hyung-Ho Park
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Barium Titanate ◽  
Ambient Condition ◽  
Molar Ratio ◽  
Diffraction Measurement ◽  
Capping Agent ◽  
Synthetic Control ◽  
Tetrabutylammonium Hydroxide ◽  
Particle Size Range

Barium titanate (BaTiO3: BTO) nanoparticles (NPs) were synthesized by chlorine-free ambient condition sol (ACS) process using heat reflux at low temperature of 90°C. The size distribution and morphology of BTO NPs were investigated by varying the concentration of tetrabutylammonium hydroxide (TBAH). The crystalline size of BTO NPs was decreased with increasing the amount of TBAH capping agent (average size changes from 54.3 to 38.7 nm for 0 to 0.5 M TBAH in X-ray diffraction measurement). The particle size of BTO NPs was principally controlled by a synthetic control of butyl chain of TBAH and also a steric effect of excess amount of TBAH. The dielectric constant of BTO NPs was decreased from 152 to 144 at 1 MHz after an adoption of TBAH capping agent with almost uniform dielectric loss (<0.027). But the dielectric constant of BTO NPs synthesized with various molar ratio of TBAH (0.1, 0.3, and 0.5) did not show a distinguished decrease. At the particle size range in this experiment, the dielectric behavior of BTO NPs was found to be mainly dependent on the TBAH ligands at BTO NPs formed during capping process, not on the size of BTO NPs.

A Study of Some Mechanical and Physical Properties for Palm Fiber/Polyester Composite

2020 ◽  
Vol 38 (3B) ◽  
pp. 104-114
Author(s):  
Samah M. Hussein
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Date Palm ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Dielectric Strength ◽  
Palm Fiber ◽  
Mechanical And Physical Properties ◽  
Polyester Composite

This research has been done by reinforcing the matrix (unsaturated polyester) resin with natural material (date palm fiber (DPF)). The fibers were exposure to alkali treatment before reinforcement. The samples have been prepared by using hand lay-up technique with fiber volume fraction of (10%, 20% and 30%). After preparation of the mechanical and physical properties have been studied such as, compression, flexural, impact strength, thermal conductivity, Dielectric constant and dielectric strength. The polyester composite reinforced with date palm fiber at volume fraction (10% and 20%) has good mechanical properties rather than pure unsaturated polyester material, while the composite reinforced with 30% Vf present poor mechanical properties. Thermal conductivity results indicated insulator composite behavior. The effect of present fiber polar group induces of decreasing in dielectric strength, and increasing dielectric constant. The reinforcement composite 20% Vf showed the best results in mechanical, thermal and electrical properties.

scholarly journals Jet Impingement Heat Transfer of Confined Single and Double Jets with Non-Newtonian Power Law Nanofluid under the Inclined Magnetic Field Effects for a Partly Curved Heated Wall

2021 ◽  
Vol 13 (9) ◽  
pp. 5086
Author(s):  
Fatih Selimefendigil ◽  
Hakan F. Oztop ◽  
Ali J. Chamkha
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Particle Size ◽  
Aspect Ratio ◽  
Power Law ◽  
Volume Fraction ◽  
Inclined Magnetic Field ◽  
Magnetic Field Effects ◽  
Power Law Nanofluid ◽  
Power Law Index

Single and double impinging jets heat transfer of non-Newtonian power law nanofluid on a partly curved surface under the inclined magnetic field effects is analyzed with finite element method. The numerical work is performed for various values of Reynolds number (Re, between 100 and 300), Hartmann number (Ha, between 0 and 10), magnetic field inclination (γ, between 0 and 90), curved wall aspect ratio (AR, between 01. and 1.2), power law index (n, between 0.8 and 1.2), nanoparticle volume fraction (ϕ, between 0 and 0.04) and particle size in nm (dp, between 20 and 80). The amount of rise in average Nusselt (Nu) number with Re number depends upon the power law index while the discrepancy between the Newtonian fluid case becomes higher with higher values of power law indices. As compared to case with n = 1, discrepancy in the average Nu number are obtained as −38% and 71.5% for cases with n = 0.8 and n = 1.2. The magnetic field strength and inclination can be used to control the size and number or vortices. As magnetic field is imposed at the higher strength, the average Nu reduces by about 26.6% and 7.5% for single and double jets with n greater than 1 while it increases by about 4.78% and 12.58% with n less than 1. The inclination of magnetic field also plays an important role on the amount of enhancement in the average Nu number for different n values. The aspect ratio of the curved wall affects the flow field slightly while the average Nu variation becomes 5%. Average Nu number increases with higher solid particle volume fraction and with smaller particle size. At the highest particle size, it is increased by about 14%. There is 7% variation in the average Nu number when cases with lowest and highest particle size are compared. Finally, convective heat transfer performance modeling with four inputs and one output is successfully obtained by using Adaptive Neuro-Fuzzy Interface System (ANFIS) which provides fast and accurate prediction results.

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