3-D Modeling and Experimental Studies for a Thermionic Dispenser Cathode Activation Process

2021 ◽  
pp. 1-6
Author(s):  
Nergis Yildiz Angin Atmaca ◽  
Emirhan Postaci ◽  
Hasan Erciyas ◽  
Ozlem Akman Gokcel ◽  
Selahattin Nesil ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Activation Process ◽  
Dispenser Cathode

scholarly journals Use of mechanical activation in the processing of gold-bearing ores and anthropogenic materials

2020 ◽  
Vol 192 ◽  
pp. 02017
Author(s):  
Natalia Litvinova ◽  
Aleksandra Kopylova ◽  
Valentina Stepanova ◽  
Hitachi Tatsumi
Keyword(s):  
Mechanical Activation ◽  
Alkali Metals ◽  
Chemical Elements ◽  
Experimental Studies ◽  
Accessory Mineral ◽  
Complexing Agent ◽  
Activation Process ◽  
Eastern Region ◽  
Trace Impurities ◽  
Gold Bearing

The results of experimental studies on the use of mechanical activation in the processing of ores and anthropogenic materials of the Far Eastern region are presented. The effectiveness of the use of electrophotoactivated solutions and complex reagents at the stage of mineral preparation has been established. Technological solutions have been proposed to reduce the loss of finely dispersed and chemically bonded gold during the processing of gold-bearing materials based on a directed change in the properties of the surface of minerals. The effectiveness of the use of the mechanochemical activation process for various aspects of the technological chain has been experimentally confirmed – a decrease in the sorption properties of materials, development of microcracks in oxidized ores for the penetration of leaching solutions into mineral aggregates, oxidation of the surface of primary ores, and removal of films from the mineral surface. Indicators of technological refractoriness of the studied ores and anthropogenic materials were revealed – a high proportion of chemically bound gold with atoms of basic and accessory mineral-forming elements, the presence of grains of the valuable component covered with oxide films, enclosed in carbonates, quartz and waste rock. The refractoriness of ores is confirmed by a high sorption capacity (the predominance of carbonaceous and clay matter), the presence of trace impurities in gold (Sb, As, Cu, Fe, Hg), which increase the consumption of cyanide during leaching. The material composition is dominated by a significant amount of chemical elements – cyanosides, actively interacting with the main complexing agent of leaching solutions – cyanide of alkali metals.

scholarly journals Research of Mechanochemical Processes of Activation of Building Materials by Air-Impact Method

2021 ◽  
Vol 304 ◽  
pp. 02009
Author(s):  
Igor Kravchenko ◽  
Mihail Erofeev ◽  
Aleksandr Fedorov ◽  
Valeriy Kondrashchenko ◽  
Diana Abdumuminova ◽  
...  
Keyword(s):  
Building Materials ◽  
Initial Period ◽  
Experimental Studies ◽  
Activation Process ◽  
Design Strength ◽  
Concrete Mixtures ◽  
Operational Characteristics ◽  
Proposed Model ◽  
Local Materials ◽  
Control Composition

To increase the specific surface area of the binder and accelerate the strength gain of fast-hardening concrete mixtures, a model has been created for calculating aeroactivators as part of mobile complexes based on new equipment for cement activation, sand enrichment, local materials, and production waste. The proposed model establishes the dependence of the rate of destruction of the dusty shell of particles on the mechanical impact of the beaters and materials` physical and mechanical characteristics. To improve the operational characteristics of the cement aeroactivator, experimental studies were carried out, the results of which made it possible to determine the rational parameters of the developed installation. Based on the test results, it was found that the use of the cement activation process with additives accelerates the hardening process of concrete and mortar mixtures in the initial period, increases the design strength of concretes and mortars by 20–40% in comparison with the strength of the control composition at the same cement consumption, and also reduces the consumption cement up to 17% to obtain concretes and mortars equal to the control composition at the design age.

SEM and Auger microanalysis studies of Cu-Be dynode surfaces at each activation condition

1978 ◽  
Vol 36 (1) ◽  
pp. 524-525
Author(s):  
T. Koshikawa ◽  
Y. Fujii ◽  
E. Sugata ◽  
F. Kanematsu
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Life Time ◽  
Activation Process ◽  
Beam Diameter ◽  
Activation Temperature ◽  
Electron Multiplier ◽  
Activation Condition ◽  
Activation Conditions

The Cu-Be alloys are widely used as the electron multiplier dynodes after the adequate activation process. But the structures and compositions of the elements on the activated surfaces were not studied clearly. The Cu-Be alloys are heated in the oxygen atmosphere in the usual activation techniques. The activation conditions, e.g. temperature and O2 pressure, affect strongly the secondary electron yield and life time of dynodes.In the present paper, the activated Cu-Be dynode surfaces at each condition are investigated with Scanning Auger Microanalyzer (SAM) (primary beam diameter: 3μmϕ) and SEM. The commercial Cu-Be(2%) alloys were polished with Cr2O3 powder, rinsed in the distilled water and set in the vacuum furnance.Two typical activation condition, i.e. activation temperature 730°C and 810°C in 5x10-3 Torr O2 pressure were chosen since the formation mechanism of the BeO film on the Cu-Be alloys was guessed to be very different at each temperature from the results of the secondary electron emission measurements.

3-D reconstruction and analysis of mammalian mitotic spindle structure

1992 ◽  
Vol 50 (1) ◽  
pp. 578-579
Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh
Keyword(s):  
Cross Sections ◽  
Mitotic Spindle ◽  
Experimental Studies ◽  
Video Camera ◽  
Three Dimensions ◽  
Mitotic Spindles ◽  
Black And White ◽  
Reconstruction Methods ◽  
Spindle Structure ◽  
Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

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