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Journal articles on the topic 'Relative magnetic permeability'
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1
Zhou, Sui Hua, Zhi Yi Chen, and Shi Min Feng. "Improvement Methods of Apparent Permeability of Ferromagnetic Core." Advanced Materials Research 712-715 (June 2013): 1876–80. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.1876.
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The performance of induction coil magnetic sensors , which usually have large dimensions and heavy weights, is mainly decided by apparent permeability of the core. But flux concentrator is a effective equipment to improve apparent permeability of the core, which will hardly increase dimensions and weights of magnetic sensors. Firstly, mathematical equations of apparent permeability are explained and influencing factors are analysed. Then influencing degrees of different parameters of the flux concentrator are simulated by Maxwell 2D/3D. The results are shown as follows. (a) The larger diameter and thickness of the flux concentrator, the better is the effect of magnetic concentration. (b) The less the gap between core and concentrator, the better is the effect of magnetic concentration. (c) The larger relative permeability of the flux concentrator, the effect of magnetic concentration is unconspicuous for the material whose relative permeabilityis larger than ten thousands.
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Bastola, Anil K., Milan Paudel, and Lin Li. "Magnetic circuit analysis to obtain the magnetic permeability of magnetorheological elastomers." Journal of Intelligent Material Systems and Structures 29, no. 14 (2018): 2946–53. http://dx.doi.org/10.1177/1045389x18781046.
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The magnetic permeability of magnetorheological elastomers must be known for their long-term use in the actual engineering systems. In this article, the magnetic permeability of both isotropic and anisotropic magnetorheological elastomers has been determined using a new method. The magnetic induction was measured and a closed magnetic circuit analysis was carried out to obtain the magnetic permeability of magnetorheological elastomers for both isotropic and anisotropic magnetorheological elastomers with 10%–50% volume concentration of carbonyl iron particles. The magnetic permeability was increased with increasing particle concentration for both isotropic and anisotropic magnetorheological elastomers as we could expect. The isotropic permeability is always lower than the anisotropic permeability. The maximum relative permeability value of 6.6 was obtained for 50% particle volume concentration. The experimental results also show a good agreement with theoretical predictions and previous investigations.
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Chandra, Bahadur Khadka. "Relative Nature of Electric Permittivity and Magnetic Permeability of Electromagnetic Wave." Indian Journal of Advanced Physics (IJAP) 2, no. 1 (2022): 17–25. https://doi.org/10.54105/ijap.C1021.041322.
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<strong>Abstract: </strong>This research is about the special theory of relativity on electric permittivity and magnetic permeability of electromagnetic wave. For this, Four Maxwell's electromagnetic equations play an important role. James Clerk Maxwell suggested that the light travel as electromagnetic wave which require no material medium for propagation. The speed of light (C) in free space is always constant and is independent of the speed of source or observer or the relative motion of the inertial system and has velocity 'C' given by. So velocity of electromagnetic waves depend on obsolute magnetic permeability and obsolute electric permittivity of free space. These two physical quantities rely on relative motion of inertial system. So are not obsolute quantity but are dependent upon the relative motion between the observer and the phenomenon observed. Electric and magnetic field of a charge rely upon the value of obsolute electric permittivity of medium. Concisely, are variant quantity. Consequently electric and magnetic field get relative for electromagnetic wave. That is electric and magnetic field depend on relative motion of inertial system for electromagnetic waves.
4
Ding, Chao, Yunhui Mei, Khai D. T. Ngo, and Guoquan Lu. "A (Permalloy + NiZn Ferrite) Moldable Magnetic Composite for Heterogeneous Integration of Power Electronics." Materials 12, no. 12 (2019): 1999. http://dx.doi.org/10.3390/ma12121999.
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Soft magnetic moldable composites (SM2Cs) would be ideally suited for the integration of magnetic components in power electronic converters because they can be formed into magnetic cores by low-temperature and pressure-less processing. However, most SM2Cs have low relative magnetic permeability, typically less than 30, and high core-loss densities at switching frequencies over 1 MHz. To improve their magnetic properties, we combine powders of Permalloy and a NiZn ferrite with an acrylic polymer to formulate a paste of SM2C. The paste can be molded and then cured below 200 °C without pressure to form cores with a relative permeability over 35 and a core-loss density at 1 MHz, 30% lower than those of commercial cores. The ease of its processing and high-performance properties makes the SM2C a good candidate material for the integration of power magnetics.
5
Katoh, Tetsuo, Hiroki Takase, and Yasushi Ohshima. "Relative Permeability of Iron-Chromium Magnetic Alloys in Alternating Magnetic Field." DENKI-SEIKO[ELECTRIC FURNACE STEEL] 64, no. 4 (1993): 252–59. http://dx.doi.org/10.4262/denkiseiko.64.252.
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Sandulyak, Alexander V., Roman Y. Tkachenko, Darya A. Sandulyak, Maria N. Polismakova, Anna A. Sandulyak, and Vera A. Ershova. "Analysis of dependence between magnetic properties of granulated ferromagnetic specimens and relation of its length to diameter." Izmeritel`naya Tekhnika, no. 6 (2020): 46–51. http://dx.doi.org/10.32446/0368-1025it.2020-6-46-51.
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Paper studies the problems about experimental determining magnetic parameters of nonuniform granular magnetics. It has been noted that the existing shortage of direct and (or) indirect experimental data on the magnetic properties of granular ferromagnetic specimens with different values of a relative length, in particular, has a negative impact on the validity of the requirements and decisions to create and ensure the performance of relevant functional elements, movable operating elements of various equipments and devices. By the example of cylindrical specimens of balls with the range of relative length 1–16 within the framework of effective medium macromodel the dependences of induction, magnetic permeability, susceptibility, magnetization and field intensity have been obtained. It has been shown that in the range of field intensity 9–47 kA/m values of induction and magnetization of investigating specimens increase, that indicates the absence of magnetic saturation of such granular (as opposed to solid) magnetics. And this is the case at almost stable values of magnetic susceptibility and permeability. Obtained results are useful in designing movable operating elements of various equipments and devices.
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Li, Xiao Yang, and Zan Dong Han. "Effect of Uniaxial Stress on Magnetic Permeability and Magnetic Loss of Low-Carbon Steel in Weak Alternating Magnetic Field." Applied Mechanics and Materials 678 (October 2014): 220–27. http://dx.doi.org/10.4028/www.scientific.net/amm.678.220.
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The inverse magnetostrictive effect provides a chance to detect the stress by measuring some magnetic parameters. So it is important to learn the effect of stress on some magnetic parameters. A measuring system to measure magnetic permeability and magnetic loss and a device to load uniaxial tension and pressure stress were developed. The result shows that magnetic permeability and magnetic loss increase with uniaxial tension stress increase and decreases with uniaxial pressure stress increase. It is also concluded that the relative change of magnetic permeability and magnetic loss decrease with increase of the included angle between the directions of the stress and magnetic field. These results suggest that magnetic permeability and magnetic loss can be further used to evaluate the stress in low-carbon steel.
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Володько, А. В., С. М. Фёдоров, Е. А. Ищенко, М. А. Сиваш, Л. В. Сопина, and А. В. Бунина. "MINIMIZING THE EFFECTIVE AREA OF SCATTERING BY MEANS OF CHANGING THE RELATIVE MAGNETIC PERMEABILITY." ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА, no. 1 (April 19, 2021): 85–88. http://dx.doi.org/10.36622/vstu.2021.17.1.013.
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Исследуется зависимость эффективной площади рассеяния (ЭПР) от относительной магнитной проницаемости материала, из которого изготавливается структура. В качестве тела моделирования был выбран шар, который изготовлен из диэлектрического материала, у которого возможно выполнять изменение относительной магнитной проницаемости. По полученным результатам моделирования построены графики зависимости максимального значения моностатической ЭПР от частоты, а также от относительной магнитной проницаемости среды. Было показано, что с увеличением относительной магнитной проницаемости материала изготовления происходит увеличение значения ЭПР объекта, а также обнаружена зависимость эффективной площади рассеяния от соотношения размеров шара и длиной волны, так при превышении порогового значения, после которого шар становится крупным объектом, ЭПР резко возрастает. По результатам исследования был построен график зависимости эффективной площади рассеяния шара от относительной магнитной проницаемости материала изготовления. Доказана возможность применения материала с частотозависимой относительной магнитной проницаемостью в качестве стелс-покрытия. В статье содержится исследуемая модель, графики полученных результатов, по которым можно легко определить зависимость ЭПР от частоты и от относительной магнитной проницаемости материала изготовления The article investigates the dependence of the effective scattering area (ESA) on the relative magnetic permeability of the material from which the structure is made. We chose a sphere as the modeling body, which is made of a dielectric material, in which it is possible to change the relative magnetic permeability. Based on the obtained simulation results, graphs of the dependence of the maximum value of monostatic ESA on frequency, as well as on the relative magnetic permeability of the medium, were constructed. It was shown that with an increase in the relative magnetic permeability of the material of manufacture, an increase in the value of the ESA of the object occurs, and the dependence of the effective scattering area on the ratio of the size of the ball and the wavelength was found, so when the threshold value is exceeded, after which the ball becomes a large object, ESA rises sharply. Based on the results of the study, a graph of the dependence of the effective scattering area of the sphere on the relative magnetic permeability of the material of manufacture was built. The possibility of using a material with a frequency-dependent relative magnetic permeability as a stealth coating was proven. The article contains the investigated model, graphs of the results obtained, by which it is easy to determine the dependence of the ESA on the frequency and on the relative magnetic permeability of the material of manufacture
9
Khadka, Chandra Bahadur. "Relative Nature of Electric Permittivity and Magnetic Permeability of Electromagnetic Wave." Indian Journal of Advanced Physics 1, no. 3 (2022): 17–25. http://dx.doi.org/10.54105/ijap.c1021.041322.
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This research is about the special theory of relativity on electric permittivity and magnetic permeability of electromagnetic wave. For this, Four Maxwell's electromagnetic equations play an important role. James Clerk Maxwell suggested that the light travel as electromagnetic wave which require no material medium for propagation. The speed of light (C) in free space is always constant and is independent of the speed of source or observer or the relative motion of the inertial system and has velocity 'C' given by . So velocity of electromagnetic waves depend on obsolute magnetic permeability and obsolute electric permittivity of free space. These two physical quantities rely on relative motion of inertial system. So are not obsolute quantity but are dependent upon the relative motion between the observer and the phenomenon observed. Electric and magnetic field of a charge rely upon the value of obsolute electric permittivity of medium. Concisely, are variant quantity. Consequently electric and magnetic field get relative for electromagnetic wave. That is electric and magnetic field depend on relative motion of inertial system for electromagnetic waves.
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Katiyar, Anurag Kumar, Alok Prakash, Antim Dangi, and Satya Kesh Dubey. "Development and validation of a low magnetic permeability measurement setup." Review of Scientific Instruments 93, no. 11 (2022): 114701. http://dx.doi.org/10.1063/5.0124348.
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Measurement of relative permeability has a significant role in deciding the suitability of magnetic material for various industrial applications. Several developments and modifications have been made that can directly or indirectly measure the permeability of such materials. However, these developments suffer from various limitations, such as low accuracy, poor resolution, and high cost of measurement. In this work, a new measurement setup has been developed to precisely measure relative permeability in the range of 1–2. The setup has been designed based on the flux metric (solenoid) method in accordance with ASTM A 342 and EN 60404-15. A comparative analysis has been performed for known materials using different flux meters to verify the performance of the measuring coil. The developed setup was further validated against the magnetic moment method, i.e., vibrating sample magnetometer (VSM), regarding the permeability measurement of these materials. The results depicted a close agreement between the output of the developed setup and VSM data. The developed system claims a relative error of less than 1% with respect to VSM in measuring the permeability of materials. Measurement uncertainty for the developed system was also determined. Such an accurate and low-cost measurement setup can become a possible solution for the permeability measurement of feebly magnetic materials.
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Yang, Fenglai, Huaxun Liu, Shusheng Gao, et al. "Nuclear Magnetic Resonance and High-Speed Centrifugation for Gas-Water Relative Permeability Curve of Low-Permeability and Tight Sandstone." E3S Web of Conferences 598 (2024): 01006. http://dx.doi.org/10.1051/e3sconf/202459801006.
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Gas-water relative permeability curve is the foundation of gas reservoir dynamic analysis and numerical simulation. It is generally obtained through gas displacing water experiment. Referring to the existing national standards, gas-water relative permeability test is carried out for low-permeability and tight sandstone. The flow is discontinuous and the curve smoothness is poor, which affects the application of gaswater relative permeability curve. Based on the comparative analysis of a large number of mercury injection and NMR experimental results of low-permeability and tight sandstone, a method to characterize the throat radius distribution of low-permeability tight sandstone based on NMR T2 spectrum is explored. Combined with high-speed centrifugal experiment, the calculation formulas of core water saturation, phase relative permeability of gas-water under different centrifugal force are established. A new method of “nuclear magnetic resonance + high-speed centrifugation” for gas-water relative permeability curve test of lowpermeability and tight sandstone is formed, and the test is carried out on Sulige low-permeability tight sandstone core. The results show that: (1) The shape of cumulative distribution curve of throat radius by mercury injection method is basically consistent with that of T2 relaxation time by NMR, and there is a good corresponding relationship between them. (2) The centrifugation process is similar to the gas displacing water process. With the decrease of water saturation, water centrifugation in rock core becomes more and more difficult until it become irreducible. (3) The core relative permeability curve obtained by the new method is consistent with the curve obtained by the standard method and has good repeatability. The new method can be used for gas-water relative permeability tests of low permeability tight sandstone. (4) The test process of the new method is unified and standard and up to 6 cores can be tested at the same time. The calculation results of water saturation and relative permeability curve are reliable and the integral curve is smooth, which greatly improves the test efficiency of gas-water relative permeability curve in lowpermeability and tight sandstone. The new method can be widely used to study the gas-water two-phase seepage law in low-permeability and tight sandstone gas reservoir.
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Bi, Yu, Xiao Ming Zhang, and Wan Jun Wang. "Design Study of Trapezoid-Shaped Magnetic Flux Concentrator for Axial Amplification Characteristics." Applied Mechanics and Materials 875 (January 2018): 77–83. http://dx.doi.org/10.4028/www.scientific.net/amm.875.77.
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In this paper, the axial magnetic field amplification characteristics of the trapezoid-shaped magnetic flux concentrator at micrometer scale are studied. The factors of the dimension parameters including the ratio of the outer and inner width, the aspect ratio, the air gap, as well as the material property including the relative permeability influencing on the magnetic gain are analyzed using the finite element method. It indicates that the concentrator with air gap shows obvious magnetic amplification. The concentrator shows intensive magnetic gain with the increasing ratio of the outer and inner width, aspect ratio and the decreasing air gap. When the dimension parameters of the length, the outer width, the inner width, and the air gap are of 1000um, 200um, 10um, and 5um respectively, the magnetic gain of 65 is obtained. Additionally, the magnetic gain increases with the relative permeability of the concentrator. When the relative permeability reaches a certain value, the magnetic gain tends to saturation. The magnetic flux concentrator has a linear working range of 12.8mT. The study can provide a theoretical reference for the design and application of the trapezoid-shaped magnetic flux concentrator.
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Xue, Kaihua, Lei Yang, Jiafei Zhao, Yanghui Li, Yongchen Song, and Shan Yao. "The Study of Flow Characteristics During the Decomposition Process in Hydrate-Bearing Porous Media Using Magnetic Resonance Imaging." Energies 12, no. 9 (2019): 1736. http://dx.doi.org/10.3390/en12091736.
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The flow characteristics during decomposition of hydrate-bearing sediments are the most critical parameters for the gas recovery potential from natural gas hydrate reservoirs. The absolute and relative permeability and the flow field distribution during the decomposition process of hydrate-bearing porous media synthetically created by glass beads are in-situ measured by using magnetic resonance imaging. The absolute permeability value increased slowly, then became stable after the decomposition amount was 50%. The relative permeability change curve is a typical X-shaped cross curve. As the hydrate decomposed, the relative permeability values of the two phases increased, the range of the two-phase co-infiltration zone increased with the increase of relative permeability at the endpoint, and the coexistence water saturation decreased. At the beginning of the decomposition, (hydrate content 100% to 70%), the relative permeability of methane and water rose rapidly from 22% to 51% and from 58% to 70%, respectively. When the amount of the remaining hydrate was less than 50%, the relative permeability curve of the hydrate-bearing glass beads almost kept unchanged. During the hydrate decomposition process, the velocity distribution was very uneven and coincided with the porous media structure.
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Zamiri, Mohammad Sadegh, Armin Afrough, Florea Marica, Laura Romero-Zerón, Benjamin Nicot, and Bruce J. Balcom. "Unsteady-State Relative Permeability Curves Derived From Saturation Data and Partial Derivatives Using Magnetic Resonance Imaging." Petrophysics – The SPWLA Journal of Formation Evaluation and Reservoir Description 65, no. 5 (2024): 699–710. http://dx.doi.org/10.30632/pjv65n5-2024a3.
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Laboratory coreflooding experiments are performed to determine relative permeability curves which characterize flow behavior in petroleum reservoirs. Commonly, numerical simulations are used to solve the inverse problem and fit the coreflooding results, assuming functional shapes for relative permeability curves. In this work, the acquisition of rapid saturation profiles was used to derive relative permeability curves, without the need for pressure and volume reading, and assuming any functional forms for relative permeability curves. The magnetic resonance (MR) imaging method—spin echo single-point imaging (SE-SPI)—acquired precise saturation profiles that were used in evaluating saturation partial derivatives. In this paper, saturation profiles of displacement experiments and their partial derivatives were used to derive capillary dispersion, fractional mobility of phases, and model-free relative permeability curves for Bentheimer sandstones. In the drainage displacement experiment, the capillary dispersion dependency on saturation demonstrates a hyperdiffusion behavior in the leading edge of the front.
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Sandulyak, Alexander, Anna Sandulyak, and Petr Shkatov. "Dependence of Granular Matrix Demagnetizing Factor on the Matrix Relative Size." Advanced Materials Research 1083 (January 2015): 32–36. http://dx.doi.org/10.4028/www.scientific.net/amr.1083.32.
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We note that for a wide range of porous, especially granular, ferromagnetics used as matrices of magnetic filter-separators, there is still an issue of defining their demagnetizing factor N which has a dramatic effect on the values of average magnetic permeability of these operating units of filter-separators. The work aims at filling the existent gaps in the issue, we supply N values depending on the relative size of such magnets as well as a respective generalizing phenomenological dependence which is characterized by an exponential realtion between the demagnetizing factor and relative size radical. The established relation allows obtaining real values of magnetic permeability of a short filter matrix thus providing an unbiased comparative estimate of its technological workability.
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Li, Qiang, Zuo Bin Yuan, Yong Ming Yang, and Cheng Hu. "The Simulated Calculation of the First Order Buoyancy Force under Different Relative Permeability of Ferrofluid." Applied Mechanics and Materials 303-306 (February 2013): 22–25. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.22.
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In this paper, the first order buoyancy force of ferrofluid is simulated calculation under external magnetic field in ferrofluid devices. The relationship between first order buoyancy force and displacement of nonmagnetic body under different relative permeability of ferrofluid，and the relationship between first order buoyancy force and relative permeability of ferrofluid are obtained.
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Kopala, Dominika, Anna Ostaszewska-Liżewska, and Roman Szewczyk. "Sensitivity Limits and Functional Characteristics of Fluxgate Sensors with Rod-Shaped Magnetic Cores." Pomiary Automatyka Robotyka 26, no. 2 (2022): 29–33. http://dx.doi.org/10.14313/par_244/29.
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Highly sensitive fluxgate magnetic field sensors with rod-shaped cores are widely used for non-destructive testing as well as for industrial applications. However, in case of both Foerster and Vacquier (two-core sensors configurations), fluxgate sensors sensitivity is directly connected with the relative magnetic permeability of the sensor’s core. It should be highlighted that the magnetic permeability of rod-shaped magnetic cores is driven mainly by the demagnetization factor determined by its slenderness (aspect ratio). The paper presents the analyses of sensitivity limits of fluxgate sensors with rod-shaped cores. On the base of estimations of demagnetization factor specific for fluxgate sensors, it is shown that in case of rod-shaped cores, the sensor’s sensitivity is connected with the shape of the core rather than its relative magnetic permeability. This conclusion is essential during the development and optimization of functional characteristics of fluxgate sensors.
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Knight, J. D., Z. Xia, E. McCaul, and H. Hacker. "Determination of Forces in a Magnetic Bearing Actuator: Numerical Computation With Comparison to Experiment." Journal of Tribology 114, no. 4 (1992): 796–801. http://dx.doi.org/10.1115/1.2920951.
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Calculations of the forces exerted on a journal by a magnetic bearing actuator are presented, along with comparisons to experimentally measured forces. The calculations are based on two-dimensional solutions for the flux distribution in the metal parts and free space, using finite but constant permeability in the metals. Above a relative permeability of 104 the effects of changes in permeability are negligible, but below 104 decreases in permeability cause significant decreases in the force. The calculated forces are shown to depend on the metal permeability more strongly when the journal is displaced from its centered position. The predicted forces in the principal attractive direction are in good agreement with experiment when a relatively low value of permeability is chosen. The forces measured normal to the axis of symmetry when the journal is displaced from that axis, however, are significantly higher than predicted by theory, even with a value of relative permeability larger than 5000. These results indicate a need for futher work including nonlinear permeability distributions.
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Sun, Jinji, Yan Lu, Lu Zhang, Yun Le, and Xiuqi Zhao. "A Method to Measure Permeability of Permalloy in Extremely Weak Magnetic Field Based on Rayleigh Model." Materials 15, no. 20 (2022): 7353. http://dx.doi.org/10.3390/ma15207353.
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In order to solve the problem that the relative permeability of the permalloy is missing and difficult to measure accurately in an extremely weak magnetic field (EWMF, <1 nT), a method to measure the permeability in EWMF based on the Rayleigh model is proposed in this paper. In this method, the Rayleigh model for the magnetic material was first introduced. Then, the test system for measuring the permeability of permalloy for the standard ring specimen was set up. Based on the test data and the Rayleigh model, the functional expression applied to obtain the permeability in EWMF is achieved. Finally, the feasibility and accuracy of the method are verified by the permeability measurement of the custom large-size ring specimen in EWMF (<1 nT) and residual field measurement based on the four-layer shielding cylinder. This method can obtain the relative permeability in any EWMF and avoid test errors caused by extremely weak magnetization signals.
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Diguet, Gildas, Gaël Sebald, Masami Nakano, Mickaël Lallart, and Jean-Yves Cavaillé. "Magnetic behavior of magneto-rheological foam under uniaxial compression strain." Smart Materials and Structures 31, no. 2 (2021): 025018. http://dx.doi.org/10.1088/1361-665x/ac3fc8.
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Abstract This study reports the development of a magneto-rheological foam, which consists in a porous matrix filled by ferromagnetic particles. The porous matrix of such a composite being easily deformable, large magnetic properties changes are expected. The measurements of the magnetic properties of such a magneto-rheological foam submitted to a compressive strain are reported. Main aspect of the magnetic properties is the low field magnetic permeability as the function of the compression and filling factor. Then, larger field magnetization measurement allowed to investigate the saturation field as a function of the filling factor. Because of the large amount of pores in the material, the magnetic relative permeability, µ r, is quite small (µ r ∼ 1). However, these materials can be easily deformed over a large range of strain providing important relative variation of the magnetic properties under mechanical solicitation. The composite magnetic permeability is increasing under compression for all the considered filling factors. A model is then developed to understand the variation of the permeability with the strain. Hence, from a simple concept consisting of taking advantage of high deformation of foams, the present study demonstrates the interest of such a highly compressible while cheap composite for obtaining a large magneto-rheological effect.
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Yan, Jin, Rongchen Zheng, Peng Chen, Shuping Wang, and Yunqing Shi. "Calculation Model of Relative Permeability in Tight Sandstone Gas Reservoir with Stress Sensitivity." Geofluids 2021 (December 10, 2021): 1–12. http://dx.doi.org/10.1155/2021/6260663.
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During the development of tight gas reservoir, the irreducible water saturation, rock permeability, and relative permeability change with formation pressure, which has a significant impact on well production. Based on capillary bundle model and fractal theory, the irreducible water saturation model, permeability model, and relative permeability model are constructed considering the influence of water film and stress sensitivity at the same time. The accuracy of this model is verified by results of nuclear magnetic experiment and comparison with previous models. The effects of some factors on irreducible water saturation, permeability, and relative permeability curves are discussed. The results show that the stress sensitivity will obviously reduce the formation permeability and increase the irreducible water saturation, and the existence of water film will reduce the permeability of gas phase. The increase of elastic modulus weakens the stress sensitivity of reservoir. The irreducible water saturation increases, and the relative permeability curve changes little with the increase of effective stress. When the minimum pore radius is constant, the ratio of maximum pore radius to minimum pore radius increases, the permeability increases, the irreducible water saturation decreases obviously, and the two-phase flow interval of relative permeability curve increases. When the displacement pressure increases, the irreducible water saturation decreases, and the interval of two-phase flow increases. These models can calculate the irreducible water saturation, permeability and relative permeability curves under any pressure in the development of tight gas reservoir. The findings of this study can help for better understanding of the productivity evaluation and performance prediction of tight sandstone gas reservoirs.
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Sun, Jinji, Jianyi Ren, Jin Li, and Yuejing Huang. "Measurement and Analysis of Magnetic Properties of Permalloy for Magnetic Shielding Devices under Different Temperature Environments." Materials 16, no. 8 (2023): 3253. http://dx.doi.org/10.3390/ma16083253.
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The relative permeability, coercivity, and remanence of permalloy are closely related to the performance of magnetic shielding devices. In this paper, the relationship between the magnetic properties of permalloy and the working temperature of magnetic shielding devices is measured. Firstly, the measurement method of permalloy properties based on the simulated impact method is analyzed. What is more, a magnetic property test system consisting of a soft magnetic material tester and a high–low temperature chamber for permalloy ring samples at different temperatures was established to measure DC and AC (0.01 Hz to 1 kHz) magnetic properties at different temperatures (−60 °C to 140 °C). Finally, the results show that compared with room temperature (25 °C), the initial permeability (μi) decreases by 69.64% at −60 °C and increases by 38.23% at 140 °C, and the coercivity (hc) decreases by 34.81% at −60 °C and increases by 8.93% at 140 °C, which are the key parameters in the magnetic shielding device. It can be concluded that the relative permeability and remanence of permalloy are positively correlated with temperature, while the saturation magnetic flux density and coercivity are negatively correlated with temperature. This paper is of great significance to the magnetic analysis and design of magnetic shielding devices.
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Li, Shixu, Miao Yu, Jun Liu, et al. "Attenuation of magneto-induced yield stress by magnetic carrier liquid in magnetorheological fluids." Applied Physics Letters 121, no. 16 (2022): 162901. http://dx.doi.org/10.1063/5.0101090.
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Magnetorheological fluids (MRFs) are composed of magnetic particles and carrier liquid that yield stress responses to the external magnetic field, a phenomenon called the magnetorheological effect. In this work, the attenuation of magneto-induced yield stress in an MRF caused by magnetic carrier liquid was observed. Compared with that of MRFs with nonmagnetic carrier liquid, the average critical strain was correspondingly increased by 53.17%, and the maximum dynamic and static yield stress were reduced by 12.98% and 13.58%, respectively. The attenuation was attributed to the magnetic carrier liquid shunting more magnetic flux density than the nonmagnetic fluid, thus decreasing the magnetization of the magnetic particles. The weakened electromagnetic interaction between particles reduced the strength of the particle chains under the magnetic field, thereby reducing the magneto-induced yield stress. A theoretical model based on the magnetism characterization in the relative permeability of carrier liquid was proposed to explain the attenuation of the electromagnetic force for particles. A physics model of magneto-mechanical coupling was simulated in COMSOL to reveal the attenuation phenomenon. Compared with that when the nonmagnetic carrier liquid with relative permeability of 1 was used, the electromagnetic force in the calculation curves was increased by 26.94 times and decreased by 99.95% when the relative permeability was 0.1 and 10 000, respectively. This work provides a methodology for the intensive mechanism study of magneto-induced yield stress.
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Maricic, A., M. Spasojevic, S. Arnaut, D. Minic, and M. M. Ristic. "The effect of structural changes on magnetic permeability of amorphous powder Ni80Co20." Science of Sintering 40, no. 3 (2008): 303–9. http://dx.doi.org/10.2298/sos0803303m.
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The structural changes of Ni80Co20 amorphous powder were tested during heating. The alloy was obtained by electrolysis from ammonia solution sulfate of cobalt and nickel on the titanium cathode. The differential scanning calorimetry (DSC) method was used to detect that the crystallization process of powder occurred in two stages with crystallization peaks temperatures of the first stage at 690 K and of the second stage at 790 K. The effect of structural relaxation and crystallization of powder on magnetic properties was predicted by measurement of the relative magnetic permeability change in isothermal and nonisothermal conditions. On the basis of the time change of relative magnetic permeability at a defined temperature in the temperature range of the first and second crystallization peak on the thermogram, the kinetics of crystallization was defined. It was predicted, that in the initial time interval, in the range of the first crystallization peak, the rate of crystallization is determined by the rate of nucleation of the amorphous part of the powder. However, in the second time interval, the crystallization rate is determined by the rate of diffusion. In the range of the second peak, in the beginning the rate of crystal growth is determined by activation energy of the atom pass from smaller to bigger crystal grain. In second time interval, the rate of crystal grain growth is determined by the diffusion rate of atoms to the location of integration into bigger crystal grains. For all processes which determine the rate of crystallization in temperature ranges of both crystallization peaks, the Arrhenius temperature dependence of rate for those processes is obtained. The relative magnetic permeability of crystallized powder at 873 K, is smaller for about 30 % than the relative magnetic permeability of fresh powder at room temperature. However, structurally relaxed powder at 573 K has an about 22 % larger magnetic permeability than the same fresh powder at room temperature.
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Nurfarahin, Ishak, King Lee Chua, and Zarina Mohd Muji Siti. "A Simulation Magnetic Induction Tomography (MIT) for Agarwood using COMSOL Multiphysics." International Journal of Engineering and Advanced Technology (IJEAT) 10, no. 3 (2021): 67–71. https://doi.org/10.35940/ijeat.C2174.0210321.
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Magnetic induction tomography is an imaging technique used to image electromagnetic properties of an object by using the eddy current effect. (MIT) is a non-destructive method that greatly is used in the agriculture industry. This method provided an opportunity to improve the quality of agricultural products. MIT simulation was used for agarwood existence detection. This paper presented for the simulation system contains 7 channel coils receiver and a channel transmitter which is a sensing detector. This experiment aims to demonstrate the reaction of induced current density and magnetic field at 10 MHz frequency. Then, it also determines the optimal solenoid coil to be used for a better outcome for the magnetic induction system. The simulation result shows that coil diameter, coil length, and coil layer have a crucial role in the great performance of the induced current and magnetic field. The more coil turns, the greater the strength of the permanent magnetic field around the solenoid coil. The result of the simulation is important and needs to be considered to verify the effectiveness of the system for developing the magnetic induction circuit design.
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Long, Haiming, Xiaojie Wu, Yunkun Lu, Haifeng Zhang, and Junjie Hao. "Effect of Polyimide-Phosphating Double Coating and Annealing on the Magnetic Properties of Fe-Si-Cr SMCs." Materials 15, no. 9 (2022): 3350. http://dx.doi.org/10.3390/ma15093350.
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Fe-Si-Cr soft magnetic powder cores (SMCs), with high electrical resistivity, magnetic permeability, saturation magnetic induction, and good corrosion resistance, are widely applied to inductors, filters, choke coils, etc. However, with the development of electronic technology with high frequency and high power density, the relative decline in the magnetic properties limits the high-frequency application of SMCs. In this paper, the phosphating process and polyimide (PI) insulation coating is applied to Fe-Si-Cr SMCs to reduce the core loss, including hysteresis loss and eddy current loss. The microstructure and composition of Fe-Si-Cr powders were analyzed by SEM, XRD, and Fourier-transform infrared spectra, respectively. The structural characteristics of the Fe-Si-Cr @ phosphate layer @ PI layer core–shell double coating were studied, and the best process parameters were determined through experiments. For SMCs with 0.4 wt% content of PI, the relative permeability is greater than 68%, and the core loss is the lowest, 7086 mW/cm3; annealed at 500 °C, the relative permeability is greater than 57%, and the core loss is the lowest, 6222 mW/cm3. A 0.4 wt% content of PI, annealed at 500 °C, exhibits the ideal magnetic properties: μe = 47 H/m, P = 6222 mW/cm3.
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Saleem, Muhammad, and Ali Rizwan. "Development of Application Specific Intelligent Framework for the Optimized Selection of Industrial Grade Magnetic Material." Polymers 13, no. 24 (2021): 4328. http://dx.doi.org/10.3390/polym13244328.
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This article attempts to introduce a simple and robust way for the classification of soft magnetic material by using multivariate statistics. The six magnetic properties including coercive magnetic field, relative magnetic permeability, electrical resistivity magnetic inductions, i.e., remanence and saturation along with Curie temperature are used for the classification of 16 soft magnetic materials. Descriptive statistics have been used for defining the prioritization order of the mentioned magnetic characteristics with coercive magnetic field and Curie temperature as the most and least important characteristics for classification of soft magnetic material. Moreover, it has also justified the usage of cluster analysis and principal component analysis for classifying the enlisted materials. After descriptive statistics, cluster analysis is used for classification of materials into four groups, i.e., excellent, good, fair and poor while defining the prioritization order of materials on a relative scale. Principal component analysis reveals that the relative permeability is responsible for defining 99.69% of total variance and is also negatively correlated with the coercive magnetic field. Therefore, these two characteristics are considered the responsible factors for categorically placing the enlisted materials into four clusters. Furthermore, principal component analysis also helps in figuring out the fact that a combined influential consequence of relative permeability, coercive magnetic field, electrical resistivity and critical temperature are responsible for defining prioritization ordering of materials within the clusters. The material’s suitability index is identified while making use of adjacency and decision matrices obtained from material assessment graph and relative importance of magnetic properties, respectively. Afterward this material suitability index is used to rank the enlisted materials based on selected attributes. According to the suitability index, the best choice among enlisted soft magnetic materials is Supermalloy, Magnifer 7904 which is present in group 1 labeled as excellent by multivariate analysis. Therefore, the results of graph theory are in accordance with cluster analysis and principal component analysis, thus confirming the potential of this intelligent approach for the selection application specific magnetic materials.
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Sandulyak, Anna, Alexander Sandulyak, Dmitry V. Oreshkin, and Marina Popova. "Applied Model of Magnetization of a Granulated Material." Applied Mechanics and Materials 467 (December 2013): 76–80. http://dx.doi.org/10.4028/www.scientific.net/amm.467.76.
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Results of researches (of magnetic permeability) of elementary effective magnetic channel in porous (granulated) material are given. Such results permit to calculate a relative intensity of field between the grains.
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Tsepelev, Vladimir. "Nanocrystalline Soft Magnetic Toroidal Cores of the Highest Relative Magnetic Permeability and Low Coercive Force." Advanced Materials Research 716 (July 2013): 276–80. http://dx.doi.org/10.4028/www.scientific.net/amr.716.276.
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All the technologies of the melt quenching preparation ensure its time-temperature treatment to not only improve but also stabilize the metal structure and properties with every melt. The influence of annealing temperature of nanocrystalline alloy Fe72.5Cu1Nb2Mo1.5Si14B9 on the structure and magnetic properties has been investigated. The relation between numerical values of the coercive force, the initial magnetic permeability and the magnetic hysteresis loop rectangularity factor allows optimizing a mode of nanocrystalline alloy heat treatment.
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Ahmad, Abid, Bhagyashree Mishra, Andrew Foley, Leslie Wood, and Maggie Yihong Chen. "High Permeability Photosintered Strontium Ferrite Flexible Thin Films." Micromachines 12, no. 1 (2021): 42. http://dx.doi.org/10.3390/mi12010042.
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The paper is focused on the development and optimization of strontium ferrite nanomaterial and photosintered flexible thin films. These magnetic thin films are characterized with direct current (DC) and high frequency measurements. For photosintered strontium ferrite samples, we achieved relative complex permeability of about 29.5-j1.8 and relative complex permittivity of about 12.9-j0.3 at a frequency of 5.9 GHz.
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Bormio-Nunes, Cristina, and Fernando Froes. "Magnetostriction reduction and magnetic permeability enhancement of Ti added Fe0.7Co0.3 alloy." Journal of Applied Physics 133, no. 12 (2023): 125109. http://dx.doi.org/10.1063/5.0140457.
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The current work presents the study of three alloys, (1) the binary Fe0.7Co0.3 alloy (atomic fraction), (2) the addition of 3 at. % of Ti, and (3) the addition of 3 at. % of Ti and 1% of Nb. The interest is to increase the permeability of this binary alloy due to the additions of Ti and Nb, since Fe–Co alloys with Co content in the range of 27–35 at. % have much lower permeability than the commercial equiatomic alloy. The advantage of low Co Fe–Co alloys is the lower price compared to the equiatomic one. The alloys were produced by arc melting and were subsequently hot rolled and annealed in the final thickness at 1200 °C over 24 h. Microstructure characterization revealed single α-phased alloys with body centered cubic structures. Positive results were observed in the magnetic and electric properties of the (Fe0.70Co0.30)97Ti3 alloy compared to Fe0.7Co0.3, meaning the decreasing saturation magnetostriction λs, and the growth of the maximum relative permeability by 24% and of the resistivity by 63%, occurred without a change in the coercive field and in the maximum magnetic induction. The (Fe0.7Co0.3)97Ti3 alloy's maximum magnetic relative permeability is μrmax = 855 and occurs at a field of only 160 A/m, this field being more than two times lower compared to the one of the binary alloy. On the other hand, the addition of Ti + Nb has improved the deformation performance of the (Fe0.7Co0.3)97Ti3 alloy at high temperatures and did not change the magnetostriction, nor the resistivity. The quaternary alloy presents a maximum magnetic relative permeability of μrmax = 270 at 1960 A/m and a maximum magnetic induction reduced by 14% compared to the other two alloys.
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Neamţu, Bogdan Viorel, Florin Popa, Ecaterina Ware, et al. "Hydrothermal Deposition of ZnO Layer on Fe-Based Amorphous Fibres Used for the Preparation of Cold Sintered Fibre-Based Soft Magnetic Composites." Coatings 12, no. 10 (2022): 1527. http://dx.doi.org/10.3390/coatings12101527.
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This paper presents findings on the influence of hydrothermal deposition processing parameters (precursor concentration and deposition duration) on the characteristics of ZnO layers deposited on the surface of amorphous Fe-based fibres. The characteristics of the coated fibres, especially the deposited layer, were investigated from structural, morphological, chemical, thermal and magnetic points of view. It was found that the use of a zinc acetate-based solution of 0.05 M concentration and a deposition duration of 24 h leads to a continuous, thin and adherent layer of ZnO on the surface of the fibres. The thickness of the ZnO layer is 450–500 nm, as shown by TEM-EDX investigations. The ZnO coated fibres were used to prepare fibre-based soft magnetic composites via a cold sintering process. The composites obtained are the first reported soft magnetic composites based on amorphous fibres. The coercive field of the cold sintered composites is 3.5 to 8.6 times lower, and the maximum relative permeability is 2.4 times larger, than the best coercive field and the maximum relative permeability reported until now for a crystalline fibre-based soft magnetic composite. The initial relative permeability of cold sintered composites is constant up to the frequency of 1000 Hz.
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Beard, Les P., and Jonathan E. Nyquist. "Simultaneous inversion of airborne electromagnetic data for resistivity and magnetic permeability." GEOPHYSICS 63, no. 5 (1998): 1556–64. http://dx.doi.org/10.1190/1.1444452.
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Where the magnetic permeability of rock or soil exceeds that of free space, the effect on airborne electromagnetic systems is to produce a frequency‐independent shift in the in‐phase response of the system while altering the quadrature response only slightly. The magnitude of the in‐phase shift increases as (1) the relative magnetic permeability is increased, (2) the amount of magnetic material is increased, and (3) the airborne sensor gets nearer the earth’s surface. Over resistive, magnetic ground, the shift may be evinced by negative in‐phase measurements at low frequencies; but over more conductive ground, the same shift may go unnoticed because of the large positive in‐phase response. If the airborne sensor is flown at low levels, the magnitude of the shift may be large enough to affect automatic inversion routines that do not take this shift into account, producing inaccurate estimated resistivities, usually overestimates. However, layered‐earth inversion algorithms that incorporate magnetic permeability as an additional inversion parameter may improve the resistivity estimates. We demonstrate this improvement using data collected over hazardous waste sites near Oak Ridge, Tennessee, USA. Using resistivity inversion without magnetic permeability, the waste sites are almost invisible to the sensors. When magnetic permeability is included as an inversion parameter, the sites are detected, both by improved resistivity estimates and by estimated magnetic permeability.
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Du, Jin-Hong, Chao Sun, Shuo Bai, Ge Su, Zhe Ying, and Hui-Ming Cheng. "Microwave Electromagnetic Characteristics of a Microcoiled Carbon Fibers/paraffin Wax Composite in Ku Band." Journal of Materials Research 17, no. 5 (2002): 1232–36. http://dx.doi.org/10.1557/jmr.2002.0182.
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The complex relative permittivity ∈γ and permeability μγ of microcoiled carbon fibers (MCCFs) imbedded in paraffin wax were measured at Ku band frequencies (12.4–18 GHz). Both the real and imaginary parts of the complex relative permittivity of the MCCFs/paraffin wax composite decreased with increase of the frequency. The real part of the complex relative permeability of the composite increases with increase of the frequency, and the imaginary part is nonzero and nearly constant over the measured frequency range. The dielectric loss tangent (tan δ∈), the magnetic loss tangent (tan δm), and amplitude attenuation factor (α) were determined as well. On the basis of the experimental results, the MCCFs/paraffin wax composite is mainly a kind of dielectric lossy material with small magnetic loss and diamagnetism in the Ku band.
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Neto, K. Skeff, A. F. Bakuzis, P. C. Morais, et al. "The influence of aggregates and relative permeability on the magnetic birefringence in ionic magnetic fluids." Journal of Applied Physics 89, no. 6 (2001): 3362–69. http://dx.doi.org/10.1063/1.1345867.
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Zárybnická, Lucie, Marek Pagáč, Radek Ševčík, Jaroslav Pokorný, and Martin Marek. "Effect of Topology Parameters on Physical–Mechanical Properties of Magnetic PLA 3D-Printed Structures." Magnetochemistry 9, no. 12 (2023): 232. http://dx.doi.org/10.3390/magnetochemistry9120232.
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This work aims to characterize 3D-printed structures composed of a thermoplastic material (polylactic acid (PLA)) containing a combination of magnetic particles composed of iron(III) oxide (hematite) and iron(II)–iron (III) oxide (magnetite) with various infill densities and print orientations in regard to their possible processing by Fused Filament Fabrication additive technology. The correct processing temperatures have been determined using thermal analysis, and the paramagnetic and mechanical properties of the samples have been tested. The relative permeability has been identified to be strongly dependent on the topology parameters of the tested samples. The results of the inductance values for the samples without magnetic additives (infill densities 50% and 100%) have been detected to be comparable; nonetheless, the magnetic samples with 100% infill density has been found to be about 50% higher. A similar trend has been observed in the case of the values of the relative permeability, where the magnetic samples with 100% infill density have been measured as having an about 40% increased relative permeability in the comparison with the samples without magnetic additives (infill densities 20–100%). Finite Element Modelling (FEM) simulations have been applied to determine the magnetic field distributions and, moreover, to calculate the holding forces of all the printed samples. The maximum value of the holding force for the minimum distance of the plastic plate has been found to reach a value of almost 300 N (magnetic sample with 100% infill density). The obtained comprehensive characterization of the printed samples may be utilized for designing and tuning the desired properties of the samples needed in various industrial applications.
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Rovers, J. M. M., J. W. Jansen, and E. A. Lomonova. "Modeling of Relative Permeability of Permanent Magnet Material Using Magnetic Surface Charges." IEEE Transactions on Magnetics 49, no. 6 (2013): 2913–19. http://dx.doi.org/10.1109/tmag.2012.2236103.
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Ayachit, Agasthya, and Marian K. Kazimierczuk. "Sensitivity of effective relative permeability for gapped magnetic cores with fringing effect." IET Circuits, Devices & Systems 11, no. 3 (2017): 209–15. http://dx.doi.org/10.1049/iet-cds.2016.0410.
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Guo, Yuhang, Baozhi Pan, and Lihua Zhang. "A New Method to Identify Reservoirs in Tight Sandstones Based on the New Model of Transverse Relaxation Time and Relative Permeability." Geofluids 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/6787038.
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Relative permeability and transverse relaxation time are both important physical parameters of rock physics. In this paper, a new transformation model between the transverse relaxation time and the wetting phase’s relative permeability is established. The data shows that the cores in the northwest of China have continuous fractal dimension characteristics, and great differences existed in the different pore size scales. Therefore, a piece-wise method is used to calculate the fractal dimension in our transformation model. The transformation results are found to be quite consistent with the relative permeability curve of the laboratory measurements. Based on this new model, we put forward a new method to identify reservoir in tight sandstone reservoir. We focus on the Well M in the northwestern China. Nuclear magnetic resonance (NMR) logging is used to obtain the point-by-point relative permeability curve. In addition, we identify the gas and water layers based on new T2-Kr model and the results showed our new method is feasible. In the case of the price of crude oil being low, this method can save time and reduce the cost.
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Thompson, Frank. "Measuring the permeability of magnetic materials in the GHz region." Physics Education 58, no. 6 (2023): 065025. http://dx.doi.org/10.1088/1361-6552/acfb6a.
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Abstract Magnetic materials have always been important in the commercial world and, as our transport systems are switching to electrification from fossil fuels, they are likely to become more so. Relative permeability, μ r, is one parameter which characterizes such materials and this article discusses some measurements of μ r, made on powdered iron oxide and two ferrite magnetic materials. Preliminary measured values of μ r range from 1.5 to 4 and the imaginary part of μ r, show that magnetic losses occur in the GHz region. An idea for improved measurements is suggested.
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Park, Hyun Ho, Heehyuk Lee, and Deuk-Kyu Hwang. "Regression Analysis for Predicting the Magnetic Field Shielding Effectiveness of Ferrite Sheets." Electronics 14, no. 2 (2025): 310. https://doi.org/10.3390/electronics14020310.
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In this paper, a method to predict near-field magnetic shielding effectiveness (NSE) of ferrite sheets is proposed by measuring their relative permeability. The NSE prediction for ferrite sheets is developed using eight regression models based on higher-order terms of permeability, extracted through Minitab’s regression analysis using data from the measured NSE and relative permeabilities of the ferrite sheets. To analyze the accuracy of the predicted NSE in comparison to the measured NSE, the mean square error (MSE) was computed. As a result, the extracted regression models enable fast and accurate NSE predictions for ferrite sheets up to 100 MHz, achieving an MSE of less than 1.0, in contrast to numerical simulation methods that require several hours.
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Birčáková, Zuzana, Peter Kollár, Bernd Weidenfeller, Ján Füzer, Radovan Bureš, and Mária Fáberová. "Iron Based Soft Magnetic Composite Material Prepared By Injection Molding." Powder Metallurgy Progress 21, no. 1 (2021): 10–17. http://dx.doi.org/10.2478/pmp-2021-0002.
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Abstract Soft magnetic composite materials consisting of FeSi powder and polypropylene were prepared by the injection molding method, with different polypropylene contents of 25, 30 and 35 vol. %. The magnetic and electrical properties as well as the structure of the composites were investigated. The samples exhibited very low porosity, high electrical resistivity, relatively low coercivity, sufficient saturation magnetic flux density and permeability, and high resonant frequency. FeSi particles were found to be well insulated from each other and homogeneously dispersed in the polymer matrix of the composite. The observed isotropic structure was confirmed by the fitting of the experimental dependence with the analytical expression of the reversible relative permeability vs. magnetic flux density.
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Paltanea, Gheorghe, Veronica Manescu Paltanea, Iosif Vasile Nemoianu, and Horia Gavrila. "Non-Oriented Silicon Iron Alloys Used in Efficient Electrical Motor Production." Key Engineering Materials 821 (September 2019): 229–36. http://dx.doi.org/10.4028/www.scientific.net/kem.821.229.
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In this paper four non-oriented electrical steel grades M400-50A, M400-65A, M300-35A and NO20, utilizing a laboratory single sheet tester, were analyzed. For the magnetic measurements the peak magnetic polarization of 1 T was chosen. The frequency was variated between 3 Hz and 400 Hz. The isotropic electrical steel sheets were cut through punching technology, along the rolling direction. The experimentally determined energy losses were decomposed, using the loss separation theory, into hysteresis, classical and excess components. The relative magnetic permeability was analyzed and its parts, real and imaginary permeability were computed. The non-oriented alloy magnetic properties’ variation as a function of frequency was plotted and explained in the paper.
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Yap, Yun Kee, Pei Ching Oh та Evan Yew Jin Chin. "Development of αFe2O3-TiO2/PPOdm Mixed Matrix Membrane for CO2/CH4 Separation". E3S Web of Conferences 287 (2021): 02013. http://dx.doi.org/10.1051/e3sconf/202128702013.
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Magnetophoretic dispersion of magnetic fillers has been proven to improve gas separation performances of mixed matrix membrane (MMM). However, the magnetic field induced is usually in a horizontal or vertical direction during membrane casting. Limited study has been conducted on the effects of rotational magnetic field direction towards dispersion of particles. Thus, this work focuses on the rearrangement of paramagnetic iron oxide-titanium dioxide (αFe2O3-TiO2) nanocomposite in poly (2,6-dimethyl-1,4-phenylene oxide) (PPOdm) membrane via rotational magnetic field to investigate the dispersion of filler and effects towards its overall gas separation performance. The paramagnetic fillers were incorporated into polymer via dry phase inversion method at different weight loading. MMM with 3 wt% loading shows the best performance in terms of particle dispersion and gas separation performance. It shows the greatest relative particles count and least agglomerates via OLYMPUS™ Stream software with image taken by optical microscope. Relative to pristine membrane, it displays a permeability and selectivity increment of 312% and 71%. MMM with 3 wt% loading was refabricated in the presence of rotational magnetic field to enhance the dispersion of paramagnetic fillers. Results display an increment of selectivity by 8% and CO2 permeability by 46% relative to unmagnetised MMM of 3 wt% loading.
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Hu, Bo, Jingang Fu, Wenxin Yan, Kui Chen, and Jingchen Ding. "Normalization of Relative-Permeability Curves of Cores in High-Water-Content Tight Sandstone Gas Reservoir." Energies 18, no. 9 (2025): 2335. https://doi.org/10.3390/en18092335.
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The gas–water relative-permeability relationship in tight gas is complex due to interactions between the gas and water phases within the porous media in the reservoir. To clarify the fluid occurrence and the gas–water relative-permeability behavior in such reservoirs, the Dongsheng tight water-bearing reservoir from the Ordos Basin of China is taken as the research object. A non-steady state method is employed to explore the co-permeability of gas and water phases under dynamic conditions. The irreducible water saturation of different core samples is analyzed using nuclear magnetic resonance (NMR) centrifugation. The Simplified Stone equation is applied for phase permeability normalization. The results indicate that with the decrease in core permeability, the irreducible water saturation increases, and the gas and water permeability decreases. When the displacement pressure difference increases, the gas phase permeability decreases, and the water phase permeability increases. The centrifugal method is effective in reducing the saturation of bound water in rock cores. The displacement method forms channels using gas, which effectively removes free water, particularly in larger or smaller pores. In contrast, centrifugation further displaces water from smaller or capillary pores, where flow is more restricted. Based on these experimental findings, a relationship between displacement pressure difference, critical irreducible water saturation, and residual gas saturation is established. The Stone equation is further refined, and a phase permeability normalization curve is proposed, accounting for the true irreducible water saturation of rock. This provides a more accurate theoretical framework for understanding and managing the gas–water interaction in tight gas reservoirs with a high water content, ultimately aiding in the optimization of reservoir development strategies.
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Li, Hengtao, Yan Liu, Huan Yao, and Xianxian Wang. "Research on quantitative characterization method of tensile and compressive stress based on incremental magnetic permeability principle." Journal of Physics: Conference Series 2951, no. 1 (2025): 012087. https://doi.org/10.1088/1742-6596/2951/1/012087.
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Abstract In this study, non-destructive quantitative characterization of stresses in low, medium, and high carbon steels was carried out based on the principle of incremental permeability (IP) detection. First, a special fixture was designed and constructed to perform calibration experiments on a single flat plate tensile specimen to obtain the incremental magnetic permeability signals at different compressive and tensile stress levels. Subsequently, the relationship between the magnetic parameter and the stress characterization was analyzed. Finally, a network model was established to realize the quantitative characterization of tensile and compressive stresses in low, medium, and high carbon steels using the magnetic parameter. The results show that the incremental magnetic permeability detection technique can effectively predict the carbon steel stresses non-destructively and quantitatively, and the average relative errors of the model predicted low, medium, and high carbon steel stresses are 1.60 MPa, 1.28 MPa, and 2.54 MPa, respectively. The methods and conclusions proposed in this study provide important references for non-destructive testing of carbon steel stresses.
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Pesic, O., M. Spasojevic, B. Jordovic, P. Spasojevic, and A. Maricic. "Effect of electrodeposition current density on the microstructure and magnetic properties of nickel-cobalt-molybdenum alloy powders." Science of Sintering 46, no. 1 (2014): 117–27. http://dx.doi.org/10.2298/sos1401117p.
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Nanostructured nickel-cobalt-molybdenum alloy powders were electrodeposited from an ammonium sulfate bath. The powders mostly consist of an amorphous phase and a very small amount of nanocrystals with an mean size of less than 3 nm. An increase in deposition current density increases the amorphous phase percentage, the density of chaotically distributed dislocations and internal microstrains in the powders, while decreasing the mean nanocrystal size. The temperature range over which the structural relaxation of the powders deposited at higher current densities occurs is shifted towards lower temperatures. A change in relative magnetic permeability during structural relaxation is higher in powders deposited at higher current densities. Powder crystallization takes place at temperatures above 700?C. The formation of the stable crystal structure causes a decrease in relative magnetic permeability.
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Valentyn, Glyva, Bakharev Volodymyr, Kasatkina Natalia, et al. "Design of liquid composite materials for shielding electromagnetic fields." Eastern-European Journal of Enterprise Technologies 3, no. 6 (111) (2021): 25–31. https://doi.org/10.15587/1729-4061.2021.231479.
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This paper reports the principles of design and the examined protective properties of liquid materials for shielding the electric, magnetic, and electromagnetic fields over a wide frequency range. The materials were made on the basis of iron ore concentrate and a pigment additive, with water-dispersed and geopolymer paints used as a matrix. The tests of protective properties for the electrical and magnetic components of the electromagnetic field of industrial frequency showed that the electric field shielding coefficients at a concentration of the screening substance of 15−60 % (by weight) equaled 1.1−8.6; magnetic field – 1.2−5.3. The shielding coefficients of the material based on a water-dispersed paint are lower than those of a geopolymer one, which can be explained by the oxidation of an iron-containing component and a decrease in electrical conductivity. The shielding coefficients of the electromagnetic field with a frequency of 2.45 GHz are 1.2−7.9. The highest coefficients are inherent in the material with filler made of iron ore concentrate and titanium-containing pigment powder in a ratio of 1:1. To design materials with the required (predictable) protective properties, the relative magnetic, dielectric permeability of materials was calculated. It is shown that the obtained data are acceptably the same as the results from direct measurements of magnetic and dielectric permeability and could be used to calculate the wave resistance of the material and the predicted reflection coefficient of electromagnetic waves. Thus, there is reason to assert the need to build a database on the frequency dependence of effective magnetic and dielectric permeability in order to automate the design processes of composite materials with predefined protective properties.
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Lee, Jae-Gon. "Directional Monopole Antenna Using a Planar Lossy Magnetic (PLM) Surface." Journal of Electromagnetic Engineering and Science 23, no. 4 (2023): 351–54. http://dx.doi.org/10.26866/jees.2023.4.r.177.
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A directional monopole antenna using a planar lossy magnetic (PLM) surface is proposed in this paper. When a monopole antenna is designed vertically on the ground plane composed of a perfect electric conductor (PEC) and a perfect magnetic conductor (PMC), the surface current on the ground plane cannot flow on the PMC and only flows in one direction on the PEC. Therefore, the electromagnetic (EM) wave of such a monopole antenna can radiate in the direction perpendicular to the ground. Alternatively, a PLM surface such as a ferrite sheet with a high relative permeability was employed to achieve EM properties similar to the PMC. To verify the feasibility of the proposed antenna, a ferrite sheet with a relative permeability of 20 and a magnetic loss tangent of 10 at 2 GHz was utilized to implement the half PMC ground plane, and the monopole antenna was bent for miniaturization. The measured peak gain and the -10 dB bandwidth was about 1.3 dBi and 23% at the resonant frequency, respectively.
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Zárybnická, Lucie, Martin Marek, Radek Ševčík, Radek Stolín, Jaroslav Pokorný, and Jiří Šál. "Effect of Infill Density of the Printed PET-G Structures Containing Iron Oxides on Magnetic Properties." Magnetochemistry 9, no. 1 (2022): 2. http://dx.doi.org/10.3390/magnetochemistry9010002.
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This work aims to characterize printing structures with various infill densities composed of a thermoplastic material containing magnetic particles composed of mainly Iron(III) oxides with regard to their possible processing with the additive technology of Fused Filament Fabrication. A polyethylene terephthalate glycol (PET-G) structural thermoplastic with the addition of Iron(III)) oxides has been selected, and correct processing temperatures have been determined using thermal analysis. The paramagnetic properties of printed products consisting of different filling densities have been tested. Relative permeability has been identified to be strongly dependent on the printed internal structures of tested products. The samples composed of the densest structure have shown relative permeability higher by 18% with respect to the sample printed with the least dense structure. Finite Element Modelling (FEM) simulations have been applied to determine magnetic field distributions and, moreover, to calculate the holding forces of all printed samples. The performed simulations confirmed that produced composites might be utilized as magnetic switches and sensors or as more advanced components for homogenizing electric motors’ magnetic fields. Moreover, magnetic properties might be tuned according to the specific needs printing structure with the suitable density.