scholarly journals INFLUENCE OF SMALL FRACTION OF POLYGRANULAR FILL OF ROTATING DRUM ON SELF-OSCILLATION SWING

2019 ◽  
pp. 31-37
Author(s):  
Deineka Kateryna
Keyword(s):  
Visual Analysis ◽  
Large Fraction ◽  
Relative Size ◽  
The Self ◽  
Spherical Particles ◽  
Rotating Drum ◽  
Crushed Material ◽  
Maximum Range ◽  
Size Of Particles ◽  
Degree Of Filling

The influence of the structure of two-fractional polygranular fill of a rotating drum on the self-oscillation swing is considered. The pulsating mode of flow of such intrachamber fill is used in the self-oscillating grinding process in a tumbling mill. Spherical particles of non-coherent granular material of 2.2 mm size were used as a large fraction modeling the grinding bodies. Cement was used as the small fraction modeling the particles of the crushed material. The factors of experimental studies were accepted: the gaps between particles of large fraction degree of filling at rest dispersed particles of small fraction 0, 25, 50 and 100%, the relative size of particles of large fraction in the drum chamber 0.519, 0.733, 1.04, 1.47, 2.08, 2.93, 4.15 and 5.87% (drum chamber radius 212, 150, 106, 75, 53, 37.5, 26.5 and 18.75 mm), the chamber degree of filling at rest 25, 35 and 45%. The method of visual analysis of fill motion patterns in the cross section of a rotating chamber and measurement of dilatation was applied.Video of the fill pulsating flow was taken. The magnitude of the self-oscillation swing was estimated by the increase in the difference of the maximum and minimum values of the fill dilatation over one period of pulsating. The maximum range of self-oscillation swing reached the value of 1.36. The change of the self-oscillation swing from zero at the beginning of self-excitation of pulsations to the maximum value with the greatest increase of dilatation was revealed. The effect of a decrease in the maximum range of self-oscillation swing with enhanced fill coherent properties has been registered. The attenuation of the spray of particles of large fraction in the chamber due to the coherent effect of the small fraction was established. An increase in the self-oscillation swing of single-grain fill was found with a decrease in the relative particle size and the chamber degree of filling. A decrease in the self-oscillation swing of two-fractional fill was found with an increase in the content of small fraction, a decrease in the relative size of particles of a large fraction, and an increase in the chamber degree of filling.

scholarly journals THE DRUM ROTATION VELOCITY VALUE WHEN AUTO-OSCILLATION SELF-EXCITATION WITH MAXIMUM SWING OF A POLYGRANULAR INTRACHAMBER FILL

2020 ◽  
pp. 61-69
Author(s):  
Kateryna Deineka ◽  
Yurii Naumenko ◽  
Anatolii Zmiievskyi
Keyword(s):  
Visual Analysis ◽  
Large Fraction ◽  
Relative Size ◽  
Experimental Studies ◽  
Rotation Velocity ◽  
The Self ◽  
Spherical Particles ◽  
Crushed Material ◽  
Fill Fraction ◽  
Degree Of Filling

The influences of the structure of two-fractional polygranular intrachamber fill on the drum rotation velocity value when auto-oscillation self-excitation with maximum swing is considered. The pulsating mode of flow of such intrachamber fill is used in the self-oscillating grinding process in a tumbling mill. Spherical particles of non-coherent granular material of 2.2 mm size were used as a large fraction modeling the grinding bodies. Cement was used as the small fraction modeling the particles of the crushed material. The factors of experimental studies were accepted: the gaps between particles of large fraction degree of filling at rest dispersed particles of small fraction 0, 25, 50 and 100%, the relative size of particles of large fraction in the drum chamber 0.519, 0.733, 1.04, 1.47, 2.08, 2.93, 4.15 and 5.87% (drum chamber radius 212, 150, 106, 75, 53, 37.5, 26.5 and 18.75 mm), the chamber degree of filling at rest 25, 35 and 45%. The method of visual analysis of transient processes of self-oscillating fill flow modes in the cross section of a rotating chamber was applied. Measurements of the drum rotation velocity during fill self-excited self-oscillations were performed. The magnitude of the self-oscillation swing was estimated by the increase in the difference of the maximum and minimum values of the fill dilatation over one period of pulsating. The magnitude of the relative drum rotation velocity at the maximum range of fill self-oscillation swing varied within 0.777-1.4. The effect of a decrease in the relative drum rotation velocity value, when the maximum polygranular intrachamber fill self-oscillations swing, with enhanced fill coherent properties has been registered. A decrease in the relative rotational velocity was established with a decrease in the relative particle size of large fill fraction and an increase in the content of small fill fraction and an increase in the chamber degree of filling. A sharp intensification of the decrease in the relative rotation velocity at a value of the relative size of large particles of less than 0.015 is revealed.

scholarly journals ESTABLISHING THE ROTATION SPEED VARIATION RANGE LIMITS FOR AUTO-EXCITATION OF SELF-OSCILLATING GRINDING IN A TUMBLING MILL

2020 ◽  
Vol 4 ◽  
pp. 32-35
Author(s):  
Kateryna Deineka ◽  
Yurii Naumenko
Keyword(s):  
Visual Analysis ◽  
Rotation Speed ◽  
Relative Size ◽  
Fine Fraction ◽  
Coarse Fraction ◽  
The Self ◽  
Cement Clinker ◽  
Crushed Material ◽  
Degree Of Filling ◽  
Tumbling Mill

The influence of the structure of a two-fraction polygranular feed of the chamber on the value of the drum rotation speed at auto-excitation of self-excited oscillations with a maximum swing is considered. Such a pulsating mode of movement of the charge is used in the self-oscillating process of grinding in a tumbling mill. The coarse fraction simulated the grinding bodies was steel bullets with a relative size ψdb=0.026. The fine fraction, simulated the particles of the crushed material, was a cement clinker with a relative particle size ψdm=0.00013. Variable factors of experimental studies were: the degree of filling the chamber in the state of rest κbr=0.25; 0.29; 0.33 and the degree of filling the gaps between the particles of the coarse fraction with particles of the fine fraction κmbgr=0.0625; 0.375; 0.6875; 1. The method of visual analysis of transient processes of self-oscillating modes of feed behavior in the cross section of the rotating drum chamber is applied. Measurements of the speed limits of the drum rotation were carried out with auto-excitation of self-oscillations of the filling. The magnitude of the self-oscillation swing was estimated by the increase in the difference between the maximum and minimum values of the filling dilatancy for one period of pulsations. An increase in the upper limit of the speed range ψω2 with a decrease in κbr and κmbgr was established. The growth rate of ψω2 increases at low values of κbr and κmbgr. Some increase in the lower limit of the ψω1 range with a decrease in κbr and κmbgr was revealed. An increase in the range of speeds of rotation was recorded at the maximum range of self-oscillations ψω1–ψω2 with a decrease in the connected interaction of the intra-mill filling. This coherent interaction is due to an increase in κbr and κmbgr. The value of the ψω1–ψω2 range varies from 1.01–1.03 at κbr=0.33 and κmbg=1 to 1.22–1.66 at κbr=0.25 and κmbgr=0.0625. The range gets its maximum value with fine and superfine grinding

scholarly journals The effect of the filling degree of the tumbling mill chamber on the bifurcation value of the froude number

2021 ◽  
pp. 21-24
Author(s):  
Kateryna Deineka ◽  
Yurii Naumenko ◽  
Tamara Myronenko
Keyword(s):  
Froude Number ◽  
Visual Analysis ◽  
Relative Size ◽  
Experimental Studies ◽  
Fine Fraction ◽  
Coarse Fraction ◽  
Spherical Particles ◽  
Charge Movement ◽  
Filling Degree ◽  
Tumbling Mill

The influence of the filling degree of the drum chamber on the bifurcation value of the Froude number in the case of self-excitation of self-oscillations of a two-fraction granular charge with a minimum swing is considered. Such a pulsating mode of the charge movement is used in the self-oscillating grinding process in a tumbling mill. The coarse fraction that simulated the milling bodies consisted of spherical particles of an incoherent granular material with a relative size in the chamber ψb=0.00733. The fine fraction, simulating the material to be ground, was cement with a relative particle size ψm≈0.092∙10-3. The value of the adopted analogue of the kinematic viscosity of the two-fraction granular loading approached the value of 10-3 m2/s. The main variable factor in experimental studies was the filling degree of the drum chamber with loading at rest κb=0.25, 0.35, and 0.45. An additional factor was the degree of filling the gaps between the spherical particles of the coarse fraction with particles of the fine fraction κb=0, 0.25, 0.5, and 1. The method of visual analysis through the transparent end wall of the chamber of transient processes of the loading behavior with a smooth change and fixation of the velocity was applied. The bifurcation minimum value of the rotation speed was recorded, at which the steady-state circulation mode of the load movement turns into a transient pulsation one with a minimum swing. A decrease in the bifurcation values of the Froude number Frb on the cylindrical surface of the chamber with an increase in κb has been established. An increase in the intensity of the decrease in Frb with an increase in κm was revealed. The recorded effect is due to an increase in the connected properties of a two-fraction loading during self-excitation of self-excited oscillations with an increase in κb and κm. The numerical values of the boundaries of the range of bifurcation values of the Froude number for a tumbling mill Frb=0.0484–1.17 have been determined. The obtained Frb range corresponds to the Reynolds value in the range Re=40–197. The maximum Frb value is obtained with coarse grinding. An increase in the likelihood of self-excitation of self-oscillations of the intra-chamber loading with a decrease in the fineness of grinding was revealed

scholarly journals Establishing the effect of a simultaneous reduction in the filling load inside a chamber and in the content of the crushed material on the energy intensity of self-oscillatory grinding in a tumbling mill

2021 ◽  
Vol 1 (1 (109)) ◽  
pp. 77-87
Author(s):  
Kateryna Deineka ◽  
Yuriy Naumenko
Keyword(s):  
Energy Intensity ◽  
Large Fraction ◽  
Fine Fraction ◽  
Sharp Decrease ◽  
Dynamic Effect ◽  
The Self ◽  
Cement Clinker ◽  
Solid Loading ◽  
Oscillatory Process ◽  
Crushed Material

The effect of a simultaneous change in the degree of filling a chamber with load κbr and in the content of the crushed material κmbgr on the efficiency of the self-oscillatory grinding process has been estimated. Using a method of numerical modeling based on the results of experimental visualization of the flow has helped establish an emergent dynamic effect of the sharp increase in the self-oscillatory action of two-faction loading at a joint reduction in κbr and κmbgr. A significant decrease in the passive quasi-solid loading motion zone has been detected, as well as an increase in the active pulsation zone and a growth of dilatancy. The manifestation of the effect is enhanced by the simultaneous interaction of increasing the scope of self-oscillations and weakening the coherent properties of particles in a loose large fraction under the influence of the particles of fine fraction. A significant decrease in the values of the inertial loading parameters has been established: maximum dilatancy υmax, the relative scale of self-oscillations ψRυ, the maximum share of the active part of κfammax, and the generalized complex degree of dynamic activation Ka. A 2.65-time growth of υmax was detected, ψRυ increased by 5 times, κfammax ‒ by 4.36 times, Ka ‒ by 18.4 times, at a joint decrease in κbr from 0.45 to 0.25, in κmbgr ‒ from 1 to 0. The synergistic technological effect of a sharp decrease in the specific energy intensity Еo/Еs has been established, as well as an increase in the relative performance Co/Cs in the self-oscillatory grinding, due to a significant increase in the dynamic action of loading, which is exacerbated by the joint interaction of reduced κbr and κmbgr. The process of the self-oscillatory grinding of cement clinker has been investigated. A 62 % reduction in Еo/Еs and a 125 % increase in Co/Cs were detected at a joint decrease in κbr from 0.45 to 0.25, in κmbgr ‒ from 1 to 0.125. The established effects make it possible to substantiate the parameters for the energy-efficient self-oscillatory process of grinding in tumbling mills with a conventional structure

scholarly journals Political Storytelling on Instagram: Key Aspects of Alexander Van der Bellen’s Successful 2016 Presidential Election Campaign

2017 ◽  
Vol 5 (4) ◽  
pp. 15-25 ◽  
Author(s):  
Karin Liebhart ◽  
Petra Bernhardt
Keyword(s):  
Political Communication ◽  
Presidential Election ◽  
Digital Storytelling ◽  
Visual Analysis ◽  
The Self ◽  
Election Campaigns ◽  
Relevant Factor ◽  
One Year ◽  
Key Aspects ◽  
Presidential Election Campaign

This article addresses the strategic use of Instagram in election campaigns for the office of the Austrian Federal President in 2016. Based on a comprehensive visual analysis of 504 Instagram posts from Green-backed but independent presidential candidate Alexander Van der Bellen, who resulted as winner after almost one year of campaigning, this contribution reconstructs key aspects of digital storytelling on Instagram. By identifying relevant image types central to the self-representation of the candidate, this article shows how a politician makes use of a digital platform in order to project and manage desired images. The salience of image types allows for the reconstruction of underlying visual strategies: (1) the highlighting of the candidate’s biography (<em>biographical strategy</em>), (2) the presentation of his campaign team (<em>team strategy</em>), and (3) the presentation of the candidate as a legitimate office holder (<em>incumbent strategy</em>). The article thus sheds light on visual aspects of digital storytelling as relevant factor of political communication.

scholarly journals A low-temperature hydrothermal synthesis of submicron spherical BaF2

RSC Advances ◽  
2021 ◽  
Vol 11 (63) ◽  
pp. 40051-40058
Author(s):  
Xiao Li ◽  
Yuxiang Zhao ◽  
Bo Li ◽  
Shuxuan Wang ◽  
Xingwu Zou
Keyword(s):  
Hydrothermal Synthesis ◽  
Low Temperature ◽  
Hydrothermal Method ◽  
Self Assembly ◽  
The Self ◽  
Spherical Particles

BaF2 submicron spherical particles, formed by the self-assembly of nanocubes, were prepared by a low-temperature hydrothermal method with the aid of EDTA-2Na.

Modeling of Interaction Layers from Conductive Microparticles with TE Electromagnetic Wave

2013 ◽  
Vol 646 ◽  
pp. 245-248
Author(s):  
Anton Anzulevich ◽  
Leonid But’ko ◽  
Sergey Moiseev ◽  
Il’ya Zotov
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Radiation ◽  
Incident Radiation ◽  
Spherical Particles ◽  
Metal Powders ◽  
Micro Particles ◽  
Wave Heating ◽  
Powder Metals ◽  
Size Of Particles

Dependences of distribution, penetration, reflection and absorption of microwaves in the layers of conductive micro-particles on the frequency of the incident radiation and size of particles are obtained and investigated. Layers of conductive spherical particles as the shell, and without it are accepted in our work as the most common model of powder metals. So, this study allows to describe and classify features of electromagnetic wave heating of various metal powders and to predict the performance, in which it will be effective heating of metal powders by electromagnetic radiation.

Evaluation of Deformation Behavior of Silica-Filled Rubber under Monotonic and Cyclic Straining

2013 ◽  
Vol 535-536 ◽  
pp. 185-188
Author(s):  
Yoshihiro Tomita ◽  
Shinya Nakata ◽  
Masato Naito ◽  
Kisaragi Yashiro
Keyword(s):  
Coupling Agent ◽  
Deformation Behavior ◽  
Volume Fraction ◽  
Relative Size ◽  
Distribution Patterns ◽  
Deformation Characteristics ◽  
Filled Rubber ◽  
Size Of Particles ◽  
Cyclic Straining ◽  
Mechanisms Of Deformation

To clarify the essential deformation characteristics of silica-filled rubber, we construct the finite element homogenization models of silica-filled rubber with newly proposed nonaffine molecular chain network model of rubber. These models can reflect the generation of complicated inter-fillers connecting phases where the characteristics of rubber are intricately changed depending on the volume fraction of silica coupling agent and relative size of particles and their location. The results obtained clarified the essential physical enhancement mechanisms of deformation resistance and hysteresis loss for rubber filled with silica with different distribution patterns under diffrent rate of deformation. The volume fraction of coupling agent essentially affects the deformation behavior of silica filled rubber which suggests the high controlability of the material characteristics of silica filled rubber as compared with carbon black filled rubber.

Masculine Bodies, Selfies, and the (Re)configurations of Intimacy

2017 ◽  
Vol 21 (1) ◽  
pp. 112-130 ◽  
Author(s):  
Begonya Enguix ◽  
Erick Gómez-Narváez
Keyword(s):  
Qualitative Data ◽  
Visual Analysis ◽  
The Self ◽  
Self Management ◽  
Body Parts ◽  
Structured Interviews

This article is part of a research about the use of selfies in two different apps, Grindr and Instagram. We are interested in exploring how selfies relate to masculine bodies and produce different negotiations of intimacy. Selfies are personal, bodily centered, and highly visible. Understanding their production can contribute to the discussion on the digital exposure of intimacy and on the (self) management of masculine bodies. We consider selfies as discursive media that merge the visual and the discursive. Through their practice, users actively negotiate their masculine bodies and their intimacies and question and/or affirm hegemonies. Based on visual analysis and qualitative data obtained from observation and structured interviews, our results point out to the active production of selfies in relation to the different apps and to different styles of bodies that (in)visibilize different body parts and/or emotional traits. Selfies (re)present hegemonic, resistant, and emergent bodies with different understandings of intimacy.

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