Influence Of Constant Magnetic Field Research Articles

Influence of Constant Magnetic Field upon Fatigue Life of Commercially Pure Titanium.

Cyclic tests of the multicycle fatigue of commercially pure titanium were performed under normal conditions (without a magnetic field) and after exposure to a constant magnetic field of varying density (B = 0.3, 0.4, 0.5 T). It was shown that the application of the constant magnetic field of varying density led to a fold increase in the average number of cycles to destruction of the VT1-0 titanium samples by 64, 123, and 163%, respectively. Scanning electron microscopy revealed that the magnetic field led to a 1.45-fold increase in the critical length of the fracture (the width of the fatigue crack growth zone) and a 1.6-fold decrease in the distance between the fatigue striations in the accelerated crack growth zone of the destroyed titanium samples. It was established that a subgrain (fragmented) structure formed in the area of the fatigue growth of the fracture of the titanium samples. The size of the subgrains corresponded to the spaces between the fatigue striations, which had an inhibitory influence on the microcrack propagation. Collectively, the revealed facts are indicative of a higher material resistance to fatigue fracture propagation and increased operation resources under the fatigue tests in the magnetic field, which correlates with the data on the growth of the average number of cycles to fracture of the VT1-0 titanium samples.

Calculation of energy and magnetic susceptibility of Fe atomic system during dislocation motion in magnetic field

PurposeThe purpose is to calculate the change in the total energy of a small fragment of an idealized lattice of iron (in its pure form and with impurity atoms) containing an edge dislocation during its elementary motion at one interatomic spacing, both under the influence of a constant magnetic field and without it. The introduction of a magnetic field into the system is aimed at checking the adequacy of the description of the phenomenon of magnetoplasticity by changing the total energy of the atomic system.Design/methodology/approachThe design procedure is based on a quantum-mechanical description of the switching process of the covalent bond of atoms in the dislocation core. The authors used the method of density functional theory in the Kohn-Shem version, implemented in the GAUSSIAN 09 software package. Using the perturbation theory, the authors modeled the impact of an external constant magnetic field on the energy of a system of lattice atoms.FindingsThe simulation results confirmed the effect of an external constant magnetic field on the switching energy of the covalent bond of atoms in the dislocation core, and also a change in the magnetic susceptibility of a system of atoms with a dislocation. This complements the description of the magnetoplastic effect during the deformation of metals.Originality/valueThe authors created quantum-mechanical models of the dislocation motion in the Fe crystal lattice: without impurities, with a substitutional atom Cr and with an interstitial atom C. The models take into account the influence of an external constant magnetic field.

Effect of Fe3O4 nanoparticles on germination of seeds and concentration of elements in Helianthus annuus L. under constant magnetic field

The aim of the study was to investigate the effect of the Fe3O4 nanoparticles (Fe-NPs) on the germination of sunflower seeds, early growth of seedlings and the concentration of selected elements in seedlings. The influence of constant magnetic fields in systems with and without Fe-NPs was investigated. Experiments were done on seeds subjected to germination under constant magnetic field (0 (control), 5, 25 and 120 mT) for 7 days in the presence of solution containing 0, 50 or 500 ppm Fe-NPs. No significant effect of Fe-NPs and the magnetic field on germination of seeds and the growth of seedlings has been demonstrated. In most cases, a decrease in germination parameters was observed. For the majority of samples the relative decrease in the concentrations of elements was demonstrated mainly for samples without Fe-NPs. Interestingly, a significant decrease in the concentrations of trivalent (including iron - Fe) and toxic elements in samples containing Fe-NPs in relation to control samples was observed. The authors suggest that in this case the binding (adsorption) of these elements in the roots and seeds of the sunflower by Fe-NPs took place. This explains the lower iron content in seedlings than in seeds prior to sowing.

Influence of Constant Magnetic Field on Mechanical Properties and Thermal Stability of the Amorphous Alloys Based on Co, Fe and Ni

Influence of Constant Magnetic Field on Mechanical Properties and Thermal Stability of the Amorphous Alloys Based on Co, Fe and Ni

Influence of constant magnetic field on plastic characteristics of paramagnetic metals

The reported study analyses the influence of weak constant magnetic fields (up to 0.6 T) on plastic characteristics of paramagnetic materials, e.g. titanium and aluminum. Such characteristics as microhardness, plasticity parameter and creeping process were investigated. In the process of work, it has been established that weak magnetic fields can essentially change plastic characteristics of the materials under consideration. The effect of magnetic field is linearly dependent on induction, becoming evident in changing microhardness of commercially pure polycrystalline titanium and aluminum.

Analysis of the Effect of a Constant Magnetic Field on the Results of Infrared Thermography Quality Control of the Polymeric Parts

This article studies the effect of a constant magnetic field (CMF) on the temperature signal characterizing premature curing of a binder during nondestructive testing of the polymeric materials by the infrared thermography method. Diagrams and thermographs, showing the change of the temperature distribution on the surface of the controlled specimen in case of the deviation of the curing agent amount from the norm by 5 wt % under the effect of the magnetic field, are presented. Orientational phenomena in the polymeric material under the influence of CMF are demonstrated by controlling the damping effect of the light energy in the polarized light. A replica of the magnetic state of the specimen is presented.

Influence of Constant Magnetic Field on Electrodeposition of CoW/Cu/CoW Composite

Influence of Constant Magnetic Field on Electrodeposition of CoW/Cu/CoW Composite

Influence of Constant Magnetic Fields on Defect Formation under Conditions of Heat Shock in Surface Layers of Silicon

The work is devoted to the study of defect formation processes in the near-surface layers of silicon under thermal shock conditions and to the effect of preliminary exposure in a constant magnetic field on this process. As a result of investigations it was established that dislocation half-loops near the local heat source are formed in the near-surface layers of Si (with a depth of up to 30 μm) after a current pulse of density j> 5.1010 A / m2 passing through the metallized film on the silicon surface. In addition, it was found that preliminary exposure of samples in a constant magnetic field leads to an increase in the dislocation density compared to samples not exposed in a magnetic field.

Specific Features of the Structural Organization and Thermomechanical Properties of Pectin–Ag0–P4VP Nanocomposites Formed Under the Action of Constant Magnetic Field

By using a complex of structural methods and thermomechanical analysis, we study the influence of constant magnetic field on the specific structural features and thermomechanical properties of pectin–Ag0 –P4VP nanocomposites. By the methods of X-ray diffraction analysis, it is demonstrated that, in the course of chemical reduction of Ag+ cations in polyelectrolyte-metal complexes under the action of a constant magnetic field, a nanocomposite is formed on the basis of pectin–P4VP polyelectrolyte complex and Ag0 nanoparticles but with a higher content of metallic silver than in the absence of magnetic fields. It is shown that, under the action of the field, silver-containing nanocomposites are formed with much higher temperatures of glass transition and lower temperatures of transition into the viscous state. These composites are also more susceptible to relative deformation.

Increase in the efficiency impregnating sperm serie's capabilities out of the organism

There is a number of works in which it is reported about positive impact of physical factors on maturing of ova. The positive effect of stimulation of development of cages by the pulse of electric field, the helium neon laser is noted. Earlier positive influence of constant magnetic field on quality indicators of sperm at artificial insemination has been proved. Technology in vitro is most often used for thawing of cattle sperm. The freezing and subsequent thawing of spermatozoa induce adverse development of intracellular changes (increase in the level of reactive oxygen species, damage to membrane structures), reduces the survival and functional activity of cells. The plasma membrane of sperm contains a sufficiently large amount of unsaturated fatty acids undergoing peroxidation, which causes its destabilization of ionic homeostasis violation cells, and decreases the potential of the plasma membrane of mitochondria, DNA fragmentation, and without falling lower antioxidant protection. The aim of this work was to increase the efficiency of fertilizing capacity of sperm outside the body with the use of hormonal and biophysical methods of influence, establishing criteria for the metabolic viability of spermatozoa.

Research into the biosorption process of heavy metal ions by the sediments from stations of biological iron removal

The article considers the possibility of using the sediments from stations of biological iron removal for the biosorption of heavy metal ions (IHMs) from both natural groundwaters and washing waters of enterprises with galvanic cycles. The processes of extracting Zn 2+ ions (up to 50 mg/dm 3 ), Cu 2+ (up to 16 mg/dm 3 ), Ni 2+ (up to 1.3 mg/dm 3 ), Cr 6+ (up to 2.0 mg/dm 3 ) on the bacterial structures of iron bacteria consortia and the optimal parameters of passing this process are determined (for washing waters pH=8.5–9.0). The influence of constant magnetic field with intensity of 20–60 mT, as well as the influence of different kinds of sediments from stations of biological iron removal on the efficiency of the process of removing IHM have been investigated. A significant percentage of the removal of IHM using calcined precipitate (98 % for Cu 2+ , 97 % for Zn 2+ , 85 % for Ni 2+ ) is due to the exoeffect that occurs at a wide temperature range of 200–400 oС. In this case, there is a smooth decrease in the mass of the sediment, indicating the combustion of the organic component and the crystallization of the amorphous phase. As a result, goethite (a-FeOOH) and lepidocrocyte (g-FeOOH) are converted into hematite (a-Fe 2 O 3 ) and magnetite (g-Fe 2 O 3 ), which have magnetic properties. When using as a reagent a fresh sediment, active involvement in the process of adsorption of heavy metal ions is carried out by biominerals, cells and polymer matrices of iron bacteria that have a crystalline structure and a large specific surface. At the same time, the effectiveness of removing IHMs was, respectively: for Cu 2+ 93 %; for Zn 2+ 92 %; for Ni 2+ 70 %. The efficiency of one-, two- and three-stage water purification schemes have been investigated. It was established that using the three-stage scheme with hydromechanical mixers and water alkalinization to pH 9.0, the efficiency of IHM removal was: for Cu 2+ up to 96 %; For Zn 2+ up to 99 %; for Ni 2+ up to 85 %. The X-ray spectral microanalysis of the sediment of the surface of the Gallioella bacterium case revealed the accumulation of IHM in the structure. The process of adsorption of IHM on the bacterial structures of consortia of iron bacteria due to their electrostatic bonding with both anionic surface of cell wall and with organic polymers isolated by cells of iron bacteria is substantiated.

Investigating the convection heat transfer of Fe3O4 nanofluid in a porous metal foam tube under constant magnetic field

An experimental study is conducted to investigate the convection heat transfer of Fe3O4/water nanofluid through a porous metal foam tube with uniform heat flux under the influence of constant magnetic field. This magnetic field is generated by four identical electromagnets. The electromagnets sequence is one of the most important parameters that has considerable effect on the convection heat transfer in this subject. Therefore, four different configurations of electromagnets are considered and the efficient arrangement is obtained by a numerical simulation using single-phase method in order to reach the higher heat transfer rate. Furthermore, the effects of Reynolds number, nanofluid weight fraction and magnetic field intensity on the forced convection heat transfer in the porous metal foam tube are examined under presence and absence of constant magnetic field. The experimental results show that the application of Fe3O4/water nanofluid enhances the convection heat transfer compared to DI-water. Additionally, implement of constant magnetic field leads to improve the convection heat transfer of nanofluid through the porous metal foam tube. This heat transfer improvement is more intensified in the lower fluid velocities as well as higher nanoparticle weight fractions. The maximum of 23.4% heat transfer enhancement is obtained by dispersion of 2% weight fraction of nanofluid inside the DI-water at Re=200 under applied magnetic field of 200G (0.02 T) intensity. A new correlation has been proposed for the Nusselt number of Fe3O4/water nanofluid in terms of Reynolds number, Prandtl number, nanoparticle weight fraction and magnetic field intensity which predicts the experimental data accurately.

Positive and Negative Aspects of Electrode Reactions of Hydrogen Evolution and the Influence of a Constant Magnetic Field

Nowadays, the application of electrode reactions, including those concerning hydrogen evolutions, attracts great attention in industry and in power engineering worldwide. Thus, new ways of increasing the efficiency of electrode processes are of particular interest. One of them may involve a Constant Magnetic Field (CMF). The magnetic field influences both electrons and ionized atoms leading to dynamic effects (e.g. electrolyte movement in the layer adjacent to the electrode resulting from the Lorentz force). Investigations carried out with the CV method (Cyclic Voltammetry) proved that the reaction rate constant of hydrogen production increases under the influence of CMF. Alloys well adsorbing hydrogen such as Co-Mo, Co-W, Co-Mo-W (their composition was selected by the EDX method – Energy Dispersive X-ray Analysis) and alloys well absorbing hydrogen such as Co-Pd was obtained. CMF catalyzed the increase of the reaction rate of hydrogen generation, hydrogen probably being the main ecological energy source of the future. This finding was confirmed by SEM (Scanning Electron Microscopy). The influence of CMF on so-called hydrogen corrosion of metals was also established.

Influence of constant magnetic field on the properties of waste phosphogypsum and fly ash composites

The paper presents a study of the effect of constant magnetic field on composites used in building industry. The effect of changes was obtained both by direct exposure of the samples to CMF and by using magnetically treated mixing water. Particularly good results were obtained in flexural strength test for (gypsum–phosphogypsum) composite, in which that parameter increased by 30% (from 2.35 to 3.07MPa), as well as for (cement–fly ash–phosphogypsum) one, in which it increased by 150% (from 2.39 to 6.11MPa). In compression strength test, that parameter for (cement–fly ash–phosphogypsum) composite improved by 110% (from 7.09 to 14.98MPa).

Influence of constant magnetic field on aggregation processes in magnetite colloids

Colloids of Fe3O4/SiO2 nanoparticles derived by a two-stage technique on the base of tetraetoxisilane soles were studied. Phase composition of the particles was analyzed by X-ray diffraction and Raman spectroscopy. It was found that phase transition of Fe3O4 into α-Fe2O3 occurs at a laser power exceeding a threshold value. The aggregation of the particles to linear structures in a constant magnetic field was studied by atomic force microscopy. The data on the change in resistance of Fe3O4/SiO2 colloids under an applied magnetic field were obtained.

Combined Analytical-Numerical Solution for MHD Viscous Flow over a Stretching Sheet

We studied the two-dimensional flow of viscous and electrically conducting fluid over a stretching sheet under the influence of constant magnetic field. Approximate analytical solution of governing nonlinear boundary layer equation via optimal homotopy asymptotic method (OHAM) is obtained. For numerical comparison we used Runge-Kutta-Fehlberg fourth-fifth-order method. The effect of different parameters on fluid flow is analyzed. It is found that the OHAM solution is very close to the numerical solution for different assigned values of parameters; this thus indicates the feasibility of the proposed method (OHAM).

Influence of Constant Magnetic Field on the Electrodeposition of Cobalt and Cobalt Alloys

Influence of Constant Magnetic Field on the Electrodeposition of Cobalt and Cobalt Alloys

Magnetofection of Human Somatic Cells with Magnetite and Cobalt Ferrospinel Nanoparticles

Superparamagnetic nanoparticles varying by their chemical composition and synthesis method were used to transfer DNA into somatic cells under the influence of constant magnetic field (method of magnetofection). Magnetite particles obtained by mechanochemical synthesis ensured higher expression of the marker gene GFP (evaluated by fluorescence intensity of the cell lysate) then particles of ferric oxide obtained by chemical co-precipitation and cobalt ferrospinel particles obtained by the mechanochemical method.

ELASTODYNAMIC RESPONSE OF VIBRATIONS IN A MAGNETO-MICROPOLAR POROUS MEDIUM POSSESSING CUBIC SYMMETRY

The present investigation is concerned with the propagation of plane waves in a micropolar porous half-space possessing cubic symmetry in contact with vacuum under the influence of constant magnetic field. After deriving the frequency equations, the behavior of curves for phase velocity, attenuation coefficient, and specific loss is depicted graphically to study the effects of magnetism and anisotropy on the propagation of waves in a micropolar porous half-space possessing cubic symmetry. The path of surface particles is also obtained for the propagation of Rayleigh waves. Some special cases of interest are also deduced from the present investigation.

Influence of constant magnetic field on the tribological parameters of rubbing couples steel-brass in surface active substances

Maintainability of surfaces of sensitive pairs of friction is analysed in surroundings with high electrical resistance in the conditions of friction. The model of tribological unit, determining conditions and conformities to the law of formation of protective tribological pellicles, is worked out. The parameters of reparation of friction surfaces are determined by a tribomagnetic method. The parameters of renewal of sensitive tribopairs are also defined on uncollapsible technologies by joint influence of triboelectrochemical method and tribomagnetic components.