scholarly journals Прямой магнитоэлектрический эффект в двухслойных керамических композитах на основе ферримагнетика Mn-=SUB=-0.4-=/SUB=-Zn-=SUB=-0.6-=/SUB=-Fe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=- и сегнетоэлектрика PbZr-=SUB=-0.53-=/SUB=-Ti-=SUB=-0.47-=/SUB=-O-=SUB=-3-=/SUB=-

2021 ◽  
Vol 63 (7) ◽  
pp. 888
Author(s):  
А.В. Калгин
Keyword(s):  
Magnetoelectric Effect ◽  
Powder Materials ◽  
Heterogeneous Environment ◽  
Effective Parameters ◽  
Experimental Conditions ◽  
Good Agreement

Under different experimental conditions, the direct magnetoelectric effect was studied in two-layer composites prepared both by joint sintering of layers of powders of ferrimagnet Mn0.4Zn0.6Fe2O4 and ferroelectric PbZr0.53Ti0.47O3 and by gluing plates pre-sintered from powder materials of Mn0.4Zn0.6Fe2O4 and PbZr0.53Ti0.47O3. It was found that sintered composites show greater values of the magnetoelectric effect than composites prepared by gluing sintered plates together. The revealed regularities are in good agreement with the conclusions from the theoreti-cal model of the effective parameters of the heterogeneous environment.

scholarly journals The substitution mechanism of Au in In-, Fe- and In-Fe-bearing synthetic crystals of sphalerite, based on the data from EPMA and LA-ICP-MS study

LITOSFERA ◽  
2019 ◽  
pp. 148-161 ◽  
Author(s):  
D. E. Tonkacheev ◽  
D. A. Chareev ◽  
V. D. Abramova ◽  
E. V. Kovalchuk ◽  
I. V. Vikentyev ◽  
...  
Keyword(s):  
Depositional Environments ◽  
Salt Flux ◽  
Research Subject ◽  
Trace Impurities ◽  
Valuable Component ◽  
Experimental Conditions ◽  
Icp Ms ◽  
Substitution Mechanism ◽  
Synthetic Crystals ◽  
Good Agreement

Research subject.Sphalerite (ZnS) is a widespread mineral that can be found in various depositional environments. During formation, this mineral can accumulate minor and trace impurities, with gold being one of the most valuable component. The issue of the chemical state of Au in sphalerite has been much discussed recently.Methods.Samples of In-, Fe- and In-Febearing sphalerite with a composition ranging from 0 to 2.5 mol.% In2S3 and 0 – 40 mol.% FeS were synthesized in an Ausaturated system using gas transport and salt flux techniques. The resulting products were subsequently investigated using EPMA and LA-ICP-MS.Results.All the elements under investigation are found to be homogeneously distributed within the sphalerite matrix. After quenching, sphalerite is shown to retain Au. Our data indicates that the observed increase in Au concentration is caused by the presence of In (up to 1.02 wt % Au) and, to a lesser extent, by that of Fe (up to ≈600 ppm Au). These elements substitute Zn in the crystal structure of sphalerite following the scheme Au+ + In3+(Fe3+) ↔ 2Zn2+, which is in good agreement with previous data obtained using the XAS method.Conclusions.A higher sulphur fugacity in the system leads to a more significant accumulation of Au in sphalerite. The concentration of Au in pure sphalerite does not exceed 10 ppm under our experimental conditions and does not depend on the activity of sulphur in the system.

scholarly journals OPTIMIZATION OF LEVOFLOXACIN REMOVAL FROM AQUEOUS SOLUTION USING ELECTROCOAGULATION PROCESS BY RESPONSE SURFACE METHODOLOGY

2021 ◽  
Vol 52 (1) ◽  
pp. 204-217
Author(s):  
Mohammed & Mohammed-Ridha
Keyword(s):  
Aqueous Solution ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Correlation Coefficient ◽  
Iron Hydroxide ◽  
Second Order ◽  
Experimental Results ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Good Agreement

This study was aimed to investigate the response surface methodology (RSM) to evaluate the effects of various experimental conditions on the removal of levofloxacin (LVX) from the aqueous solution by means of electrocoagulation (EC) technique with stainless steel electrodes. The EC process was achieved successfully with the efficiency of LVX removal of 90%. The results obtained from the regression analysis, showed that the data of experiential are better fitted to the polynomial model of second-order with the predicted correlation coefficient (pred. R2) of 0.723, adjusted correlation coefficient (Adj. R2) of 0.907 and correlation coefficient values (R2) of 0.952. This shows that the predicted models and experimental values are in good agreement. The results of the kinetic study showed that the second-order kinetic model was in good agreement with the experimental results and suggested that the mechanism of chemisorption controlled the LVX adsorption. The experimental results indicated that the adsorption of LVX on iron hydroxide flocs follows Sips isotherm with the value of the correlation coefficient (R2) of 0.937. Sips isotherm shows that both homogenous and heterogeneous adsorption can occur.

Numerical Simulation of Scouring in Overtopping Dam-break Flow

2021 ◽  
Author(s):  
Can Huang ◽  
Xiaoliang Wang ◽  
Qingquan Liu
Keyword(s):  
Numerical Simulation ◽  
Empirical Relationship ◽  
Dam Break ◽  
Experimental Conditions ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Dam Break Flow ◽  
Scouring Process ◽  
Overtopping Erosion ◽  
Good Agreement

<p>Overtopping dam-break flow has great harm to the earthen embankments due to the hydraulic erosion. Some researchers have carried out relevant model experiments, but it is difficult to achieve the experimental conditions for the actual situation. The common numerical simulation is to express the scouring process through the empirical relationship, which obviously could not reflect the real scouring process. In this paper, a new overtopping erosion model using Smoothed Particle Hydrodynamics (SPH) is proposed. When the shear stress on the sediment SPH particle exceeds the critical stress, the erosion process begins. Then, when a sediment SPH particle is completely eroded, it will begin to move and is described as a non-Newtonian fluid. The un-incipient sediment particles are treated as boundary. This model is well validated with plane dike-breach experiment, and has also achieved a good agreement with erodible bed dam-break experiment.</p>

scholarly journals STH/CFD Coupled Simulation of the Protected Loss of Flow Accident in the CIRCE-HERO Facility

2020 ◽  
Vol 10 (20) ◽  
pp. 7032 ◽  
Author(s):  
Pucciarelli Andrea ◽  
Galleni Francesco ◽  
Moscardini Marigrazia ◽  
Martelli Daniele ◽  
Forgione Nicola
Keyword(s):  
Thermal Stratification ◽  
Outlet Section ◽  
Experimental Conditions ◽  
Ansys Fluent ◽  
Internal Loop ◽  
Fuel Pin ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd ◽  
The University ◽  
Good Agreement

The paper presents the application of a coupling methodology between Computational Fluid Dynamics (CFD) and System Thermal Hydraulic (STH) codes developed at the University of Pisa. The methodology was applied to the CIRCE-HERO facility in order to reproduce the recently performed experimental conditions simulating a Protected Loss Of Flow Accident (PLOFA). The facility consists of an internal loop, equipped with a fuel pin simulator and a steam generator, and an external pool. In this coupling application, the System code RELAP5 is adopted for the simulation of the internal loop while the CFD code ANSYS Fluent is used for the sake of simulating the pool. The connection between the two addressed domains is provided at the inlet and outlet section of the internal loop; a thermal coupling is also performed in order to reproduce the observed thermal stratification phenomenon. The obtained results are promising and a good agreement was obtained for both the mass flow rates and temperature measurements. Capabilities and limitations of the adopted coupling technique are discussed in the present paper also providing suggestions for improvements and developments to be achieved in the frame of future applications.

scholarly journals A novel rapid method of purely elastic solution correction to estimate multiaxial elastic-plastic behaviour

2019 ◽  
Vol 6 (3) ◽  
pp. 269-283
Author(s):  
Nicolas Antoni
Keyword(s):  
Three Dimensional ◽  
Elastic Solution ◽  
Upper And Lower Bounds ◽  
Efficient Design ◽  
Effective Parameters ◽  
Relative Deviation ◽  
Elastic Plastic ◽  
Plastic Behaviour ◽  
A New Technique ◽  
Good Agreement

Abstract In structural analysis, it is of paramount importance to assess the level of plasticity a structure may experience under monotonic or cyclic loading as this may have a significant impact, particularly in fatigue analysis for singular areas. For efficient design analyses, it is often searched for a compromise in accuracy that consists in correcting a purely elastic analysis, generally simpler and faster to obtain compared to a full non-linear Finite Element (FE) analysis involving elastic-plastic behaviour, to estimate the actual elastic-plastic solution. There exists a great number of correction techniques in the literature among which the most famous and commonly used are Neuber and ESED energy-based methods. Nonetheless, both of them are known to provide respectively upper and lower bounds of the exact solution in most cases, with a relative deviation depending on the level of multiaxiality and on the amount of stress redistribution due to yielding. The new methodology presented in this paper is based on the well-known multiaxial Radial Return Method (RRM) revisited using effective parameters approach. By essence, it is fast and can be applied either to analytical elastic problems or to more complex three-dimensional elastic FE analyses. The accuracy of the proposed method is assessed by direct comparison with results from Neuber and ESED methods on various examples. It is also shown for each of them that this new method is very good agreement with the exact elastic-plastic solution. Highlights A new technique of purely elastic solution correction is presented and evaluated. The proposed method relies on the modification of Return Radial Method (RRM) considering effective parameters in lieu of initial elastic tensor. The obtained equation preserves the simplicity and efficiency of other well-known energy-based methods such as Neuber and ESED. It is shown on several examples that the proposed technique is in very good agreement with the exact or FE elastic-plastic solution, with very low relative deviation.

Interfacial Energy-Dispersive Spectroscopy Profile X-Ray Resolution Measurements in Variable Pressure SEM

2014 ◽  
Vol 20 (5) ◽  
pp. 1565-1575 ◽  
Author(s):  
Abdelhalim Zoukel ◽  
Lahcen Khouchaf ◽  
Jean Di Martino ◽  
David Ruch
Keyword(s):  
Electron Microscope ◽  
Energy Dispersive Spectroscopy ◽  
Shape Change ◽  
High Vacuum ◽  
Energy Dispersive ◽  
Variable Pressure ◽  
Experimental Conditions ◽  
X Ray ◽  
Scanning Electron ◽  
Good Agreement

AbstractA procedure has been developed to follow degradation of energy-dispersive spectroscopy (EDS) X-ray lateral resolution in a variable pressure scanning electron microscope. This procedure is based on evaluation of the EDS profile shape change for different experimental conditions. Some parameters affecting the X-ray resolution in high-vacuum mode have been taken into account. Good agreement between the simulated and experimental EDS profiles shows the reliability of the proposed procedure. A significant improvement in measurement of the EDS profile interfacial distance (DINT) has been achieved.

Local Contact Compliance Relations at Compaction of Composite Powders

2005 ◽  
Vol 74 (1) ◽  
pp. 164-168 ◽  
Author(s):  
Olle Skrinjar ◽  
Per-Lennart Larsson ◽  
Bertil Storåkers
Keyword(s):  
Finite Element ◽  
The Other ◽  
Powder Materials ◽  
The Finite Element Method ◽  
Self Similarity ◽  
Composite Powders ◽  
Local Contact ◽  
Contact Compliance ◽  
Metallic Composites ◽  
Good Agreement

Local contact behavior of composite powders has been investigated by using the finite element method. In previous analyses of such problems it has in general been assumed that one of the powder materials is rigid while the other deforms at loading as in such a case self-similarity prevails. This is a very good approximation for ceramic/metallic composites but may not be so when the composite consists of two materials of roughly equal hardness. An approximate compliance formula for describing this feature is proposed showing good agreement with corresponding finite element results for representative cases.

THE DIFFUSION OF A HIGHLY IONIZED PLASMA ACROSS A MAGNETIC FIELD

1965 ◽  
Vol 43 (5) ◽  
pp. 855-871 ◽  
Author(s):  
O. D. Olson ◽  
H. M. Skarsgard
Keyword(s):  
Magnetic Field ◽  
Electron Density ◽  
Inhomogeneous Magnetic Field ◽  
Experimental Conditions ◽  
Degree Of Ionization ◽  
Coulomb Collisions ◽  
Wide Range ◽  
Small Collection ◽  
Toroidal Chamber ◽  
Good Agreement

The decay of electron density and temperature has been measured in a low-pressure helium afterglow by means of double floating probes of very small collection area. The plasma was contained in a glass toroidal chamber; initial gas pressures were in the vicinity of 0.030 Torr. Magnetic confining fields from 0.004 to 0.0860 Wb/m2 were used and the degree of ionization was such that coulomb collisions were dominant. Strict criteria were adopted to ensure reliable operation of the double probes. A theory of diffusion is presented which includes interactions between all species of particles. Drift effects due to the inhomogeneous magnetic field are important at the higher field strengths and are taken into account. Reasonably good agreement is found between the theoretical and observed time constants for electron-density decay over a wide range of experimental conditions.

Die Druckverbreiterung der diffusen Heliumlinien, Vergleich zwischen Messung und Theorie im quasistatischen Bereich

1966 ◽  
Vol 21 (6) ◽  
pp. 697-718 ◽  
Author(s):  
H. Pfennig ◽  
E. Trefftz
Keyword(s):  
Stark Effect ◽  
Point Of View ◽  
Spectral Lines ◽  
Experimental Point ◽  
Line Profiles ◽  
Experimental Conditions ◽  
Part D ◽  
Upper Level ◽  
Good Agreement ◽  
Red Wing

It is difficult to discriminate between theories of pressure broadening of spectral lines through comparison with experiments. Line profiles are insensitive with respect to details of the theory, and it is difficult to keep experimental conditions clear and certain enough to make the comparison relevant. We used measurements of VIDAL 1 which are satisfactory from the experimental point of view. The wings of the diffuse He-lines 2P — nD are compared with those calculated by quasistatic theory. Part B deals with STARK effect splitting of the upper level. Part C describes the quasistatic theory of the line wings, and discusses the probability function of the so called micro field strength. In part D the results of the calculation are compared with the measurements. The comparison is relevant only for the violet wings of the triplet series. The red wing of the triplet lines and the violet wing of the singlet lines are disturbed by the forbidden component 2P — nP. The red wing of singlet lines is experimentally too inexact because of disturbing wings of neighboring triplet lines. The slope of the violet side of the triplet wings shows good agreement between theory and measurement for the far wing (large Δv). For decreasing Δv the experimental curve stays below the theoretical curve. For comparison of wing intensities it proves to be important to normalize the line profiles. It is seen that the measured height of the wings increases less with increasing main quantum number than the theoretical height.

ROUGHENING TRANSITION IN BRANCHING POLYMERS

Fractals ◽  
2003 ◽  
Vol 11 (supp01) ◽  
pp. 29-36 ◽  
Author(s):  
LIACIR S. LUCENA ◽  
LUCIANO R. DA SILVA ◽  
STÉPHANE ROUX
Keyword(s):  
Phase Diagram ◽  
Phase Boundary ◽  
Branching Ratio ◽  
Direct Numerical Simulations ◽  
Branched Polymers ◽  
Heterogeneous Environment ◽  
Original Algorithm ◽  
Roughening Transition ◽  
Analytic Computation ◽  
Good Agreement

A growth model, introduced to model the development of branched polymers in an heterogeneous environment, gives rise to clusters whose boundary is either faceted or rough. We study the transition between these two morphologies as a function of the parameters of the model, impurity concentration and branching ratio. The phase diagram is first obtained by direct numerical simulations, using an original algorithm, based on a self-regulated search of a critical point. Then an analytic computation of the phase boundary is proposed based on a simple approximation. The obtained phase boundary is in good agreement with the numerical results. The nature of the transition is discussed.

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