scholarly journals THE SINTERING PROCESS LIMITS GRINDING QUARTZ POWDER IN A PLANETARY MILL AGO-2 WITH OPTIMAL ENERGO TENSION

2018 ◽  
Vol 14 (4) ◽  
pp. 41-48
Author(s):  
I V Milyukova ◽  
S V Sobyanin
Keyword(s):  
Specific Surface ◽  
Mechanical Activation ◽  
Ultrafine Particles ◽  
Gas Permeability ◽  
Planetary Mill ◽  
Load Factor ◽  
Quartz Powder ◽  
Grinding Media ◽  
Additional Mode ◽  
Average Size

The study of the agglomeration limit of quartz powder grinding at the AGO-2 planetary mill was carried out. For operation, several modes were selected, 3 basic modes with a coefficient of filling grinding media φ=0,5; 0,6; 07, as well as one additional mode with a filling factor φ=0,4 and a smaller proportion of quartz powder. The agglomeration limit for quartz during mechanical activation on AGO-2 is the average powder diameter of 1.5 µm, and the maximum value of the specific surface is 15,000 cm2/g. The paper proposes a method for calculating the energy intensity of the AGO-2 activator, by which it was possible to estimate the optimal mode of treatment of quartz to obtain ultrafine particles with a load factor φ=0,4 and a time of mechanical activation up to 60 seconds. Determination of the average size and specific surface area of the particles after mechanical activation was carried out by the method of gas permeability Of the pocket - Goat using the device PSH-11. Measuring the temperature of the mixture of grinding media and powder in the drum was made contact thermometer TK-5.09, equipped with a thermocouple 3V9-500.

Reactive Milling and Mechanical Alloying in Electroceramics

2010 ◽  
Vol 63 ◽  
pp. 420-424
Author(s):  
Riva Rivas-Marquez ◽  
Carlos Gomez-Yanez ◽  
Ivan Velasco-Davalos ◽  
Jesus Cruz-Rivera
Keyword(s):  
Grain Size ◽  
Mechanical Activation ◽  
Raw Materials ◽  
Planetary Mill ◽  
Fabrication Technique ◽  
Nonlinearity Coefficient ◽  
Grain Sizes ◽  
Zno Varistor ◽  
Reactive Milling ◽  
Good Homogeneity

Using Mechanical Activation it is possible to obtain small grain size and good homogeneity in a ceramic piece. For ZnO varistor devices Mechanical Activation appears to be a good fabrication technique, since good homogeneity and small grain sizes are advantageous microstructural features. The typical formulation is composed by ZnO, Bi2O3, Sb2O3, CoO, MnO2 and Cr2O3 as raw materials, and during sintering, several dissolutions and reactions to form pyrochlore and spinel phases occur. When Mechanical Activation is applied to the entire formulation, it is difficult to know what processes are being mechanically activated due to the complexity of the system. The aim of the present work was to clarify how the mechanical activation is taking place in a typical ZnO varistor formulation. The methodology consisted in the formation of all possible combinations of two out of the five oxides above mentioned and to apply mechanical activation on the mixture of each pair of powders. The results showed that systems containing Bi2O3 are prone to react during mechanical activation. Also, reduction reactions were observed in MnO2. In addition, the powder mixture corresponding to the whole formulation was milled in a planetary mill, pressed and sintered, and varistor devices were fabricated. Improvement in the nonlinearity coefficient and breakdown voltage was observed.

SYNTHESIS AND CHARACTERIZATION OF FERROELECTRIC NANOCRYSTAL POWDERS OF SrBi2Ta2O9 BY A POLYMERIZABLE COMPLEX METHOD

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2514-2519 ◽  
Author(s):  
JIN-BO CHENG ◽  
AI-DONG LI ◽  
QI-YUE SHAO ◽  
YUE-FENG TANG ◽  
DI WU
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Thermal Analyses ◽  
Water Soluble ◽  
Complex Method ◽  
Powder Synthesis ◽  
Conventional Solid State Reaction ◽  
Transmission Electron ◽  
Average Size

Ferroelectric nanocrystal powders of SrBi2Ta2O9 (SBT) have been first prepared by a polymerizable complex (PC) route. The bismuth powder, strontium carbonate, and water-soluble tantalum oxalate solution were used as starting materials. Thermal analyses (TGA and DSC), x-ray diffraction (XRD), transmission electron microscopy (TEM), and conventional BET method were explored to characterize the structure, morphology, and specific surface area of PC-derived SBT powders calcined at 500-850 °C. As control samples, SBT powders were also fabricated by metalorganic decomposition (MOD) method. The XRD and TEM results indicate that high pure and well crystalline powders can be obtained at 650 °C with a average size of 50 nm. The PC-derived powder has much larger surface area than MOD-derived powder. The BET value of PC and MOD powder at 750 °C for 2h is 6.7 and 1.5m2/g, respectively. The specific surface area of powder prepared by conventional solid-state reaction is quite low, typically less than 1.5m2/g. Therefore, the feasibility of the polymerizable complex route is demonstrated in the powder synthesis of SBT with large surface area.

scholarly journals Polymer Nanocomposites Exploited Under The Arctic Conditions

2016 ◽  
Vol 1 (1) ◽  
pp. 122 ◽  
Author(s):  
A.A. Okhlopkova ◽  
L.A. Nikiforov ◽  
T.A. Okhlopkova ◽  
R.V. Borisova
Keyword(s):  
Molecular Weight ◽  
Mechanical Activation ◽  
High Molecular Weight ◽  
Polymer Matrix ◽  
Planetary Mill ◽  
Layered Silicates ◽  
The Arctic ◽  
Liquid Media ◽  
Arctic Conditions ◽  
Ultra High Molecular Weight

<p>Several technologies of the preparation of nanocomposites based on ultra-high-molecular-weight polyethylene were developed. The first technology is based on mechanical activation of layered silicates with surfactant before addition into polymer matrix. The second technology represents mixing of ultra-high-molecular-weight polyethylene with nanoparticles by joint mechanical activation in a planetary mill. The third technology is based on mixing of ultra-high-molecular-weight polyethylene with nanoparticles in liquid media under continuous ultrasonic treatment. Common features of these technologies are reaching of filler uniform distribution in a polymer matrix and significant improvement in the mechanical properties. Also, supramolecular structure of the composites was studied.</p>

scholarly journals POWER FOR PROCESSING APPLICATION FLOWS AND QUEUE SIZES IN MASS SERVICE SYSTEMS

T-Comm ◽  
2020 ◽  
Vol 14 (9) ◽  
pp. 10-16
Author(s):  
Boris Ya. Lichtzinder ◽  
◽  
Igor A. Blatov ◽  
Keyword(s):  
Queuing Theory ◽  
Load Factor ◽  
Cyclic Process ◽  
Variable Component ◽  
Strongly Correlated ◽  
Processing Application ◽  
Conditional Average ◽  
Multiservice Networks ◽  
Processing Power ◽  
Average Size

The classical queuing theory studies time series processing under the assumption of sampling independence. However, the traffic of modern multiservice networks is usually strongly correlated and the methods of classical theory do not work. In this paper, we consider the cyclic process of queuing, conditional and unconditional mutual correlations. Conditional average values of queues are considered. The concept of processing power of the flow of applications in queuing systems (QS) is introduced. It is shown that the variable component of the indicated power is determined by the change in the load factor and corresponds to the conditional average size of the queue of applications in the QS.

The Obtaining Solid Electrolytes "Ionic Salt-Natural Zeolite"

2021 ◽  
Vol 25 (2) ◽  
pp. 23-27
Author(s):  
O.N. Dabizha ◽  
T.P. Pateyuk
Keyword(s):  
Electrical Conductivity ◽  
Specific Surface ◽  
Mechanical Activation ◽  
Transport Properties ◽  
Natural Zeolite ◽  
Solid Electrolytes ◽  
True Density ◽  
Mechanochemical Method ◽  
Cold Pressing ◽  
Ionic Salt

The technology of obtaining solid electrolytes by mechanochemical method with subsequent cold pressing from inexpensive common clinoptilolite rocks and ionic salts – sodium and ammonium hydrophosphates at varying ratios of the initial components and the duration of mechanical activation is presented. Their physical and transport properties, namely, true density, hygroscopic humidity, specific surface according to Tovarov, volumetric electrical conductivity were found. Promising samples for further research were created, recommended for use as solid electrolytes.

Influence of the Mechanical Activation of Fly Ash on Strength of Ground Concrete Based on Waste Production

2021 ◽  
Vol 25 (11) ◽  
pp. 36-41
Author(s):  
D.V. Bespolitov ◽  
N.A. Konovalova ◽  
O.N. Dabizha ◽  
P.P. Pankov ◽  
E.A. Rush
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Mechanical Activation ◽  
Equilibrium Condition ◽  
Mechanical Characteristics ◽  
Road Construction ◽  
Waste Production ◽  
Direct Use ◽  
Silicon Oxygen ◽  
Physical And Mechanical Characteristics

The possibility of utilization of inactive fly ash in road concrete compositions by bringing of ash into a non-equilibrium condition with increased reactivity by mechanical activation in a vibration eraser is investigated. It was revealed that the optimal content of binder and fly ash in samples of soil concrete was 8 and 10 wt. %, respectively. It is shown that, due to mechanical activation, the specific surface area of fly ash increases by 2 times, dehydration and carbonization occur and silicon is replaced by aluminum in silicon-oxygen tetrahedra. It has been established that an increase of the content of crystalline carbonate phases is the reason for an increase in the strength of ground concrete. It is determined that the introduction of mechanoactivated fly ash into the composition of soil concretes contributes to increasing their physical and mechanical characteristics to the maximum strength grade M100. This indicates the competitiveness of ground concrete and the possibility of direct use of inactive fly ash in road construction.

Mechanochemical Synthesis of Intermetallic Compounds in the Gallium–Iridium System

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940067
Author(s):  
P. Vitiaz ◽  
N. Lyakhov ◽  
T. Grigoreva ◽  
E. Pavlov
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Activation ◽  
Intermetallic Compounds ◽  
High Energy ◽  
Planetary Mill ◽  
X Ray Diffraction ◽  
X Ray ◽  
Active Liquid ◽  
Scanning Electron

The interaction between a solid inert metal Ir and an active liquid metal Ga during mechanical activation in a high-energy planetary mill is studied by X-ray diffraction and scanning electron microscopy with high-resolution energy dispersive X-ray microanalysis. The effect of mechanical activation on the formation of GaxIry intermetallic compounds and GaxIry/Ir composites and their solubility in acids was investigated. The subsequent extraction of Ga from intermetallic compounds and composites in the mixture of concentrated acids [Formula: see text] makes it possible to produce nanoscale Ir.

Fabrication and Characterization of Cu Doped CeO2 by Hydrothermal Process for Antimicrobial Activity

2019 ◽  
Vol 391 ◽  
pp. 114-119 ◽  
Author(s):  
Yeon Bin Choi ◽  
Jeong Hun Son ◽  
Dong Sik Bae
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Hydrothermal Process ◽  
Antibacterial Properties ◽  
Reaction Times ◽  
X Ray Diffraction ◽  
Spherical Type ◽  
Average Size

Cu doped CeO2 nanopowder was synthesized by hydrothermal process at 180°C for 2~10h. The average size and distribution of the synthesized Cu doped CeO2 nanopowder was controlled by reaction times. The crystallinity of the synthesized Cu doped CeO2 nanoparticles was investigated by X-ray diffraction (XRD). The morphology of the synthesized Cu doped CeO2 nanoparticles was observed by FE-SEM. The specific surface area of the synthesized Cu doped CeO2 nanoparticles was measured by BET. The crystal size of the synthesized Cu doped CeO2 nanoparticles decreased with decreasing reaction times. The average size of the synthesized Cu doped CeO2 nanoparticles was below 10nm and narrow, respectively. The shape of the synthesized Cu doped CeO2 nanoparticles was spherical type. The specific surface area of the synthesized Cu doped CeO2 nanoparticles increased with decreasing reaction times. Antibacterial properties of Cu doped CeO2 were analyzed by MIC method. The synthesized Cu doped CeO2 nanopowders showed antibacterial properties against E.coli and B.sub bacteria.

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