Assessment of the Influence of Astronomical Cyclicity on Sedimentation Processes in the Eastern Paratethys Based on Paleomagnetic Measurements Using Discrete Mathematical Analysis

The introduction of modern methods for the mathematical processing of geological data is one of the promising areas of study and development in the field of geosciences. For example, today mathematical geology makes it possible to reliably identify astronomical cycles by measuring the scalar magnetic parameters of rocks (magnetic susceptibility). The main aim of this study is to develop a mathematical tool for identifying stable oscillation cycles (periods) in the dataset of the magnetic susceptibility of rocks in a geological section. The author’s method (algorithm) is based on the concept of discrete mathematical analysis—an innovative mathematical approach to the analysis of discrete geological and geophysical data. Its reliability is also demonstrated, by comparison with the results obtained by classical methods: Fourier analysis, Lomb periodogram, and REDFIT. The proposed algorithm was applied by the authors to analyze the material of field geological studies of the Zhelezny Rog section (Taman Peninsula). As a result, stable cycles were determined for the Pontian and Lower Maeotian sedimentary strata of the Black Sea Basin (Paratethys).

Селективный магнитный контроль толщины и степени упрочнения поверхностных слоев на стальных объектах

The dependences of measured locally magnetic characteristics of surface-hardened steel objects on the thickness and physical properties of their surface layers are studied. It is shown theoretically and experimentally that a change in the thickness of the hardened layer on the surface of steel objects affects on the magnitude of the tangential field component on the surface of the object in the interpolar space significantly , as well as the change in the strength properties of the layer affects the magnitude of the magnetic flux in the "transducer-object" circuit. It is proposed to use this difference in magnetic parameters for selective testing of the surface hardening quality. It is shown that the coercive force measured locally by the internal field and the maximum value of the magnetic flux, which can be measured using a single transducer in single measuring cycle, can be used as diagnostic parameters.

Entropy generation and induced magnetic field in pseudoplastic nanofluid flow near a stagnant point

In this present article the entropy generation, induced magnetic field, and mixed convection stagnant point flow of pseudoplastic nano liquid over an elastic surface is investigated. The Buongiorno model is employed in modeling. Through the use of the boundary layer idea, flow equations are transformed from compact to component form. The system of equations is solved numerically. The Induced magnetic spectrum falls near the boundary and grows further away as the reciprocal of the magnetic Prandtl number improves. The fluctuation of induced magnetic rises while expanding the values of mixed convection, thermophoresis, and magnetic parameters, whereas it declines for increment in the Brownian and stretching parameters. The velocity amplitude ascends and temperature descends for the rise in magnetic parameter. The mass transfer patterns degrade for the higher amount of buoyancy ratio while it boosts by the magnification of mixed convection and stretching parameters. Streamlines behavior is also taken into account against the different amounts of mixed convection and magnetic parameters. The pseudoplastic nanofluids are applicable in all electronic devices for increasing the heating or cooling rate in them. Further, pseudoplastic nanofluids are also applicable in reducing skin friction coefficient.

Towards a model of chain-by-chain magnetization of a granular medium: a variant of magnetic diagnostics of chains of spheres

In addition to information on the magnetic parameters of inhomogeneous magnetics, in particular, granular magnetics usually studied within the framework of the quasi-continuous medium model, it is of no less interest to obtain information from the standpoint of the model, when the object of study is the characteristic elements of an inhomogeneous magnetic. According to the well-proven model of selective magnetization of a granular medium, the elements that make up this medium are chains of granules – straight and sinuous, always manifesting themselves in the direction of its magnetization. They perform the function of conductor channels of the generated magnetic flux through the granular medium. As a result, it is a kind of branched «bundle» of conductor channels. For any of the chains of granules, for example, granules-balls of radius R, conceptually significant are the magnetic parameters of its conditional cores with radius r ≤ R, and these parameters, first of all, the magnetic permeability of quasi-continuous cores and magnetic induction in them, for different (in r) cores are variable, which requires appropriate magnetic diagnostics. To clarify the magnetic parameters of the conditional cores of a chain of granules-balls, as a physically self-sufficient element of a granular medium (i.e., in accordance with the model of chain-link magnetization of such a medium), it is practical to make measuring magnetic flux sensors in the core as circular sensors surrounding the contact point of granules-balls, however, not as traditional wire loops, but as circuits on thin printed circuit boards (with mounting holes) placed between adjacent balls. Based on the obtained data of the magnetic flux in cores of different radii r (r/R = 0.2–0.9) of a chain of spheres with a radius of R = 20 mm, the values of the magnetic induction B in them, as well as their magnetic permeability μ, were determined when the chain is magnetized in the solenoid by a field of strength from 4.8 to 54.5 kA/m. It is shown that with formal thickening of the cores, the values of B and μ decrease due to a decrease in the volume of the ferromagnet in the core, and for the limiting core (r/R → 1), i.e., for the chain as a whole, they correspond to the values of B and μ for a poly-ball backfill medium.

Numerical Study of MHD Third-Grade Fluid Flow through an Inclined Channel with Ohmic Heating under Fuzzy Environment

The uncertainties or fuzziness occurs due to insufficient knowledge, experimental error, operating conditions, and parameters that give the imprecise information. In this article, we discuss the combined effects of the gravitational and magnetic parameters for both crisp and fuzzy cases in the three basic flow problems (namely, Couette flow, Poiseuille flow, and Couette–Poiseuille flow) of a third-grade fluid over an inclined channel with heat transfer. The dimensionless governing equations with the boundary conditions are converted into coupled fuzzy differential equations (FDEs). The fuzzified forms of the governing equations along with the boundary conditions are solved by employing the numerical technique bvp4c built in MATLAB for both cases, which is very efficient and has a less computational cost. In the first case, proposed problems are analyzed in a crisp environment, while in the second case, they are discussed in a fuzzy environment with the help of α -cut approach, which controls the fuzzy uncertainty. It is observed that the fuzzy gravitational and magnetic parameters are less sensitive for a better flow and heat situation. Using triangular fuzzy numbers (TFNs), the left, right, and mid values of the velocity and temperature profile are presented due to various values of the involved parameters in tabular form. For validation, the present results are compared with existing results for some special cases, viz., crisp case, and they are found to be in good agreement.

Structural and Magnetic Properties of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4/ZnFe2O4 Spinel Ferrite Nanocomposites: Comparative Study between Sol-Gel and Pulsed Laser Ablation in Liquid Approaches

In this study, the samples of the ZnFe2O4 (ZFO) spinel ferrites nanoparticles (SFNPs), Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 (CNGaGdFO) SFNPs and (Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4)x/(ZnFe2O4)y (x:y = 1:1, 1:2, 1:3, 2:1, 3:1 and 4:1) (CNGaGdFO)x/(ZFO)y spinel ferrite nanocomposites (NC) have been synthesized by both sol-gel and Green pulsed laser ablation in liquid (PLAL) approaches. All products were characterized by X-ray powder diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), elemental mappings and energy dispersive X-ray spectroscopy (EDX). It was objected to tune the magnetic properties of a soft spinel ferrite material with a softer one by mixing them with different fractions. Some key findings are as follows. M-H investigations revealed the exhibition of ferrimagnetic phases for all synthesized samples (except ZnFe2O4) that were synthesized by sol-gel or PLAL methods at both 300 K and 10 K. ZnFe2O4 ferrite NPs exhibits almost paramagnetic feature at 300 K and glass-like phase at very low temperatures below 19.23 K. At RT analyses, maximum saturation magnetization (MS) of 66.53 emu/g belongs to nanocomposite samples that was synthesized by sol-gel method and x:y ratio of 1:3. At 10 K analyses, MS,max = 118.71 emu/g belongs to same nanocomposite samples with ratio of 1:3. Maximum coercivities are 625 Oe belonging to CNGaGdFO and 3564 Oe belonging to NC sample that was obtained by sol-gel route having the 3:1 ratio. Squareness ratio (SQRs = Mr/MS) of NC sample (sol-gel, 4:1 ratio) is 0.371 as maximum and other samples have much lower values until a minimum of 0.121 (laser, 3:1) assign the multi-domain wall structure for all samples at 300 K. At 10 K data, just CNGaGdFO has 0.495 SQR value assigning single domain nature. The maximum values of effective crystal anisotropy constant (Keff) are 5.92 × 104 Erg/g and 2.4 × 105 Erg/g belonging to CNGaGdFO at 300 K and 10 K, respectively. Further, this sample has an internal anisotropy field Ha of 1953 Oe as largest at 300 K. At 10 K another sample (sol-gel, 3:1 ratio) has Ha,max of 11138 Oe which can also be classified as a soft magnetic material similar to other samples. Briefly, most magnetic parameters of NCs that were synthesized by sol-gel route are stronger than magnetic parameters of the NCs that were synthesized by PLAL at both temperatures. Some NC samples were observed to have stronger magnetic data as compared to magnetic parameters of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 NPs at 10 K.