scholarly journals Multifractional Separation of Polydisperse Particles Varying in Shape and Density

2021 ◽  
Vol 27 (2) ◽  
pp. 285-293
Author(s):  
A. N. Kudi ◽  
N. A. Fedosov ◽  
V. V. Sergeev ◽  
A. G. Tarakanov ◽  
V. A. Pronin ◽  
...  
Keyword(s):  
Shear Flow ◽  
Particle Shape ◽  
Bulk Material ◽  
Seed Material ◽  
Functional Capabilities ◽  
Technological Methods ◽  
Diffusion Separation ◽  
Polydisperse Particles

A description of the functional capabilities of the technology of multifraction separation of particles by density and shape in a polydisperse bulk material is given. The technology assumes a consistent and complex use of the effects of quasi-diffusion separation and segregation of particles in a fast shear flow on a gravity slope, as well as the use of traditional technological methods of particle shape calibration. The assessment of the effectiveness of using of multifraction technology for the production of biologically valuable seed material is given.

scholarly journals The Solution of the Problem of Separating a Mixture of Polydisperse Particles of Different Shapes

2020 ◽  
Vol 26 (4) ◽  
pp. 609-618
Author(s):  
A. N. Kudi ◽  
◽  
N. A. Fedosov ◽  
V. V. Sergeev ◽  
V. N. Dolgunin ◽  
...  
Keyword(s):  
Shear Flow ◽  
Granular Material ◽  
Final Stage ◽  
Particle Interaction ◽  
Initial Mixture ◽  
Segregation Effect ◽  
Different Shapes ◽  
Diffusion Separation ◽  
Polydisperse Particles

A technology is proposed for the separation of particles by shape in a polydisperse granular material using the effects of particle interaction in a fast shear flow on a rough slope. The technology involves the fractionation of the initial mixture by the volume of particles using the segregation effect at the first stage and the calibration of the obtained particle fractions by weight using the effect of quasi-diffusion separation (migration) in the gravity flow at the second. The final stage involves the separation of particles by shape by sieve classification of fractions according to a key geometric parameter.

A Novel Method to Order Nanowire Based on Macrofludic System

2014 ◽  
Vol 1015 ◽  
pp. 32-36
Author(s):  
Ting Zhong Xu ◽  
Hebibul Rahman ◽  
Li Bo Zhao ◽  
Yu Long Zhao ◽  
Zhuang De Jiang
Keyword(s):  
Molecular Dynamics ◽  
Shear Flow ◽  
Velocity Gradient ◽  
Rotational Speed ◽  
Md Simulation ◽  
Bulk Material ◽  
Economical Method ◽  
Uniform Velocity ◽  
Novel Method

The rheology of nanowires (NWs) and nanotubes (NTs) in shear flow has been analyzed by molecular dynamics (MD) simulation and macrofludic simulation. A method based on macrofludic system for aligning NWs and NTs is demonstrated. In this method, vortex is generated near the surface of a plane by using a mushroom like turnplate. Then a uniform velocity gradient was generated on the surface of the plane. Through controlling the rotational speed of the turnplate, the rheology of NWs and NTs in suspension can be easily controlled. So it provides a more effective and economical method for the alignment of NWs and NTs, as well as forming the anisotropy NWs and NTs bulk material.

scholarly journals TECHNICAL AND TECHNOLOGICAL MAINTENANCE OF PRECISION SEPARATION OF SEED SUNFLOWER MATERIAL

2019 ◽  
pp. 40-47
Author(s):  
Bakhtiyar Aliyev ◽  
Vitaliy Yaropud
Keyword(s):  
Selection Process ◽  
Technical Equipment ◽  
Operating Modes ◽  
Seed Material ◽  
Cleaning Equipment ◽  
Adaptive Control Systems ◽  
Working Bodies ◽  
Automatic Phenotyping ◽  
Technological Methods ◽  
Varietal Purity

To obtain homogeneous genetic seed of sunflower parent components, which by varietal and sowing qualities, must have a varietal purity of 99.6-99.9%, it is necessary to ensure their precise (exact) separation according to the morphological and physico-mechanical properties in the complex. Based on the necessary requirements for the technological processes of cleaning and separation of seed mixture, a rational precision technological line has been developed for the processes of separation of seed material of sunflower, which includes automation of technical equipment. Also, to increase the efficiency of the sunflower breeding process, a device for automatic phenotyping of seeds has been added to the developed production line, which makes it possible to significantly intensify and reduce the selection process and improve the design of the crossing program due to bioinformative data analysis and sorting of seeds. As a result of the analysis of technological methods for the separation of sunflower seed material and their technical support, it has been established that the main trends in the development of precision seed cleaning equipment are the creation of adaptive control systems that allow dynamic optimization of operating modes of the working bodies without operator intervention.

The stress tensor in a two-dimensional granular shear flow

1986 ◽  
Vol 164 ◽  
pp. 107-125 ◽  
Author(s):  
Charles S. Campbell ◽  
Ailing Gong
Keyword(s):  
Shear Flow ◽  
Stress Tensor ◽  
Bulk Material ◽  
Shear Plane ◽  
Particle Packing ◽  
Simple Shear Flow ◽  
Two Dimensional ◽  
High Particle ◽  
Dense Packings ◽  
Kinetic Mode

A computer simulation is used to make a detailed study of the stress tensor in a simple shear flow of two-dimensional disks. The stresses are shown to arise from two momentum-transfer mechanisms: the 'streaming’ or kinetic mode. By which momentum is carried by particles are they move through the bulk material: and the collisional mode, by which momentum is transferred from one point to another in the material by interparticle collisions. As might be expected, the results show that the streaming mode dominates at disperse packings and the collisional mode dominates at dense packings. The friction coefficient, the ratio of shear to normal forces, is shown to decrease at high particle packing for both the collisional and streaming modes of transport. Normal-stress differences are observed within the shear plane and are evident in both the streaming and collisonal parts.

Lattice imaging and pore structure of β ferric oxyhydroxide

1978 ◽  
Vol 36 (1) ◽  
pp. 264-265
Author(s):  
T. Baird ◽  
J.R. Fryer ◽  
S.T. Galbraith
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bulk Material ◽  
Model Structure ◽  
Bulk Crystals ◽  
Lattice Imaging ◽  
Thin Sections ◽  
Ferric Oxyhydroxide ◽  
Resolution Electron ◽  
Hydrolysis Of

Introduction Previously we had suggested (l) that the striations observed in the pod shaped crystals of β FeOOH were an artefact of imaging in the electron microscope. Contrary to this adsorption measurements on bulk material had indicated the presence of some porosity and Gallagher (2) had proposed a model structure - based on the hollandite structure - showing the hollandite rods forming the sides of 30Å pores running the length of the crystal. Low resolution electron microscopy by Watson (3) on sectioned crystals embedded in methylmethacrylate had tended to support the existence of such pores.We have applied modern high resolution techniques to the bulk crystals and thin sections of them without confirming these earlier postulatesExperimental β FeOOH was prepared by room temperature hydrolysis of 0.01M solutions of FeCl3.6H2O, The precipitate was washed, dried in air, and embedded in Scandiplast resin. The sections were out on an LKB III Ultramicrotome to a thickness of about 500Å.

Precipitation in Al + 4% Cu Epitaxial Films

1968 ◽  
Vol 26 ◽  
pp. 384-385
Author(s):  
S. Herd ◽  
S. M. Mader
Keyword(s):  
Solid Solution ◽  
Bulk Material ◽  
Epitaxial Films ◽  
Detectable Change ◽  
Cu Films ◽  
Solution Treated ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Diffraction Patterns ◽  
Deposited Films

Single crystal films in (001) orientation, about 1500 Å thick, were produced by R-F sputtering of Al + 4 wt % Cu onto cleaved KCl at 150°C substrate temperature. The as-deposited films contained numerous θ-CuAl2 particles (C16 structure) about 0.1μ in size. They were transferred onto Mo screens, solution treated and rapidly cooled (within about ½ min) so as to retain a homogeneous solid solution. Subsequently, the films were aged in vacuum at various temperatures in order to induce precipitation and to compare structures and morphologies of precipitate particles in Al-Cu films with those found in age hardened bulk material.Aging for 3 weeks at 60°C or 48 hrs at 100°C did not produce any detectable change in high resolution micrographs or diffraction patterns. In this range Guinier-Preston zones (GP) form in quenched bulk material. The absence of GP in the present experiments in this aging range is perhaps due to the cooling rate employed, which might be more equivalent to an aged and reverted bulk material than to a quenched one.

Investigation of cluster layers of small netal particles by TEM, SEM, EELS and by photoacoustic spectroscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 250-251
Author(s):  
H. Seiler ◽  
U. Haas ◽  
K.H. Körtje
Keyword(s):  
Bulk Material ◽  
High Vacuum ◽  
Optical Methods ◽  
Metal Particles ◽  
Silver Particles ◽  
Low Loss ◽  
Plasmon Excitation ◽  
First Results ◽  
Diffraction Patterns ◽  
Small Metal Particles

The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared silver layers evaporated in high vacuum with cluster layers of small silver particles, evaporated in N2 at a pressure of about 102 Pa. The investigations were performed by electron optical methods (TEM, SEM, EELS) and by Photoacoustic (PA) Spectroscopy (gas-microphone detection).The observation of cluster layers with TEM and high resolution SEM show small silver particles with diameters of about 50 nm (Fig. 1 and Figure 2, respectively). The electron diffraction patterns of homogeneous Ag layers and of cluster layers are similar, whereas the low loss EELS spectra due to plasmon excitation are quite different. Fig. 3 and Figure 4 show first results of EELS spectra of a cluster layer of small silver particles on carbon foil and of a homogeneous Ag layer, respectively.

CBED analysis of impurity distributions in AlN

1990 ◽  
Vol 48 (4) ◽  
pp. 214-215
Author(s):  
Daniel Callahan ◽  
G. Thomas
Keyword(s):  
Aluminum Nitride ◽  
Bulk Material ◽  
Strong Dependence ◽  
Lattice Parameter ◽  
Promising Technique ◽  
Nitride Ceramics ◽  
Surface Phases ◽  
Convergent Beam ◽  
Oxygen Impurities

Oxygen impurities may significantly influence the properties of nitride ceramics with a strong dependence on the microstructural distribution of the impurity. For example, amorphous oxygen-rich grain boundary phases are well-known to cause high-temperature mechanical strength degradation in silicon nitride whereas solutionized oxygen is known to decrease the thermal conductivity of aluminum nitride. Microanalytical characterization of these impurities by spectral methods in the AEM is complicated by reactions which form oxygen-rich surface phases not representative of the bulk material. Furthermore, the impurity concentrations found in higher quality ceramics may be too low to measure by EDS or PEELS. Consequently an alternate method for the characterization of impurities in these ceramics has been investigated.Convergent beam electron diffraction (CBED) is a promising technique for the study of impurity distributions in aluminum nitride ceramics. Oxygen is known to enter into stoichiometric solutions with AIN with a consequent decrease in lattice parameter.

Images and Applications of Ion Explosion Spike Pits

1990 ◽  
Vol 48 (1) ◽  
pp. 584-585
Author(s):  
P. Fraundorf ◽  
J. Tentschert
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Bulk Material ◽  
Coulomb Repulsion ◽  
The Body ◽  
Atomic Scale ◽  
Early Solar System ◽  
Transmission Electron ◽  
Nuclear Particle ◽  
Particle Tracks

Since the discovery of their etchability in the early 1960‘s, nuclear particle tracks in insulators have had a diverse and exciting history of application to problems ranging from the selective filtration of cancer cells from blood to the detection of 244Pu in the early solar system. Their usefulness stems from the fact that they are comprised of a very thin (e.g. 20-40Å) damage core which etches more rapidly than does the bulk material. In fact, because in many insulators tracks are subject to radiolysis damage (beam annealing) in the transmission electron microscope, the body of knowledge concerning etched tracks far outweighs that associated with latent (unetched) tracks in the transmission electron microscope.With the development of scanned probe microscopies with lateral resolutions on the near atomic scale, a closer look at the structure of unetched nuclear particle tracks, particularly at their point of interface with solid surfaces, is now warranted and we think possible. The ion explosion spike model of track formation, described loosely, suggests that a burst of ionization along the path of a charged particle in an insulator creates an electrostatically unstable array of adjacent ions which eject one another by Coulomb repulsion from substitutional into interstitial sites. Regardless of the mechanism, the ejection process which acts to displace atoms along the track core seems likely to operate at track entry and exit surfaces, with the added feature of mass loss at those surfaces as well. In other words, we predict pits whose size is comparable to the track core width.

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