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1

Conjugate mixed convection of a micropolar fluid over a vertical hollow circular cylinder

Ahmed Alliche Sid, Ayoub Bennia, Manal Bouaziz Amina, Najib Bouaziz Mohamed

International Journal of Applied Mechanics and Engineering

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2024

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Vol. 29, no. 1

1--18

EN

This work conducts a numerical examination into the influence of a magnetic field and viscosity dissipation on the movement of a micropolar fluid over the surface of a vertical, hollow circular cylinder via conjugate mixed convection. In this investigation, we obtained a numerical solution for a non-linear differential equations-based modeling system by employing MATLAB and the bvp4c solver, which operates on a two-equation model. We show graphically how micropolar materials, conjugate heat transfer, viscous energy dissipation, buoyancy factors and magnetic field affect the temperature at the interface, local skin friction and heat transfer. By contrasting the acquired results with those found in the published research, which exhibit a high degree of concordance, the validity of the methodology is proven.

2

Magnetic pollution produced by underground XLPE 220 kV power cable in power plant

Rezzag Bara Ilies, Ayad Ahmed Nour El Islam, Krika Wafa, Fezazi Omar, Larouci Benyekhlef

Diagnostyka

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2024

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Vol. 25, No. 1

art. no. 2024104

EN

The expansion of the electrical network necessitates the construction of new power plants and the extension of overhead and underground power transmission and distribution systems. However, underground power cables, such as XPLE 220 kV, can cause significant electromagnetic pollution, particularly in urban areas. This paper focuses on the evaluation and prediction of such magnetic emissions using analytical, numerical simulation (the finite element analysis), and experimental measurement. The paper aim is to minimize the magnetic emissions through the adjustment of the horizontal and vertical distances (x, y) of cables, serving as a technical solution. Additionally, the study investigated the impact of faults with varying magnitude and frequency, considering different loads and conditions. The simulation results indicate that several factors contribute to the escalation of magnetic pollution. These factors include a close proximity between cables, faults, and high current intensities.... However, as the distance between cables increases both horizontally and vertically, the strength of the magnetic field decreases, leading to a reduction in magnetic pollution. A comparison was carried out to assess the magnetic emissions of the underground cable, revealing a notable resemblance between the measured and calculated values. Ultimately, the validated simulation model serves as a valuable tool for evaluating, predicting, and mitigating electromagnetic pollution under different fault conditions and positions.

3

Reconfigurable smart metamaterial for energy transfer control in alternating magnetic fields

Steckiewicz Adam, Stypułkowska Aneta

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 5

art. no. e149169

EN

The paper presents a metamaterial with reconfigurable effective properties, intended to operate in alternating magnetic fields. The structure of a resonator, based on a series connection of a planar inductor and a lumped capacitor, is expanded using an additional capacitor with a MOSFET transistor. Due to the presence of the controllable active element, it is possible to dynamically change the phase of the current flowing through a meta-cell and shift a frequency response within an assumed range. Since the transistor is driven by the unipolar square wave with a changeable duty cycle and time delay, two closed-loop controllers were utilized to achieve a smart material, able to automatically attain and maintain the imposed resonant frequency. As a result, the complex effective magnetic permeability of the metamaterial can be smoothly changed, during its operation, via an electrical signal, i.e. by adjusting the parameters of a control signal of the active element. The design of the meta-cell, as well as the measuring, data operation and control part, are presented in detail. An illustrative system is examined in terms of achieving the user-defined resonance point of the metamaterial. Transient responses with estimated settling times and steady-state errors and the effective permeability characteristics for the exemplary cases are shown. The meta-cell is also tested experimentally to validate the theoretically determined effective properties.

4

Study of the Influence of Cavitation and Magnetic Field on the Change of Water Properties and its Purification in a Vibrating Machine with Determination of Drive Modes

Hordieiev Anatoly, Kalda Galyna, Pashechko Mykhaylo, Hanzyuk Andriy, Tkachuk Vitaliy, Kostiuk Nazar

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 3

234--245

EN

The paper presents the results of research into the influence of low-frequency sound and magnetic fields on the change in the properties of water and its purification in a vibrating machine with an eccentric drive, which allows obtaining a constant amplitude of oscillation when the frequency of oscillations of the drive is changed. A method and construction of a vibrating machine for changing the properties of water and cleaning is proposed. Thanks to its reciprocating movement, and in the pulsation chamber and the nozzle, appropriate reactions take place. At certain oscillation frequencies, a cavitation cavity appears in the nozzle and the pulsation chamber, in which the process of splitting water molecules into active radicals takes place. At the same time, during the reciprocating movement of water through a non-magnetic nozzle, which is covered by permanent magnets, an additional effect of a variable magnetic field direction is exerted on water, which strengthens the breaking of hydrogen bonds in water molecules. Visualization of the hydrocavitation process during operation of a vibrating machine with a transparent nozzle was studied. During the experiment, changes in water parameters were studied, i.e. changes in pH, changes in the oxidation-reduction potential of treatment ORP and the total content of mineralization according to the TDS index with treatment time. The total concentration of dissolved salts decreases from 400 to 300 units, which also indicates an improvement in water quality. The rational frequency limits of the vibration drive of the machine are in the range from 18 to 23 Hz with an amplitude of oscillations of 0.002 m, and the ratio of its design parameters is determined: with a piston diameter of 0.1 m, it is recommended to use a diameter of the hole in the piston from 0.006 to 0.008 m.

5

Laboratory testing and modelling of magnetorheological elastomers in tension mode

Gutenko Denys, Orkisz Paweł, Sapiński Bogdan

Acta Mechanica et Automatica

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2024

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Vol. 18, no. 2

291--299

EN

The study deals with experimental testing and estimating the modified Dahl model parameters of magnetorheological elasto-mers (MREs) differing in volumetric concentrations of carbonyl iron particles (CIP). The authors present briefly an overview of scientific re-ports relating to MREs research. Next, they describe the structure and magnetic properties of two fabricated MREs, which were investigat-ed using a scanning electron microscope, a magnetometer and a gaussmeter. Then, they reveal the structure of a specially engineered test rig for materials sample examination and present a scenario of experiments. Next, the test results of the material’s mechanical proper-ties conducted in the absence and presence of a magnetic field were discussed. Then, they describe a modified Dahl model of the material followed by parameters estimation and validation procedure. Finally, the authors summarise the test results and outline further research steps.

6

Magnetic data modelling of salt domes in Eastern Mediterranean, offshore Egypt

Abbas Mahmoud Ahmed, Speranza Luca, Fedi Maurizio, Garcea Bruno, Bianco Luigi

Acta Geophysica

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2024

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Vol. 72, no. 2

1293--1303

EN

We analyzed magnetic data of a deep-water area in the Eastern Mediterranean, offshore Egypt where there are numerous salt domes. Regional-residual separation of the reduced to pole (RTP) magnetic anomalies was performed with the discrete wavelet transform, and the residual magnetic anomalies were interpreted as mainly due to the susceptibility contrast between sediments and salt bodies. A multiscale boundary analysis of the anomalies yielded meaningful lineaments at both large and short scales. Salt bodies lineaments are very well defined in the short-scale map. Then, we inverted the data by a nonlinear and non-iterative 3D inversion technique, to delineate the salt bodies and estimate their magnetization contrast. We used the depths obtained from the Euler deconvolution to form a set of maxima and minima constraints in the inversion. Our procedure yielded an interesting map of the top of salt in the deep-water region, entirely based on the magnetic data, which agrees well with the seismic top of salt. This is a somewhat surprising result, in some respects not obvious, demonstrating that magnetic prospecting can be an important and low-cost tool for the exploration of salt diapirs, especially when seismic data are partially or completely inaccessible or of poor quality.

7

Thermal impact of the magnetic field as a harmful effect of preparing the device structure

Lis Marek, Kobierski Michał, Chmiel Marek

Przegląd Elektrotechniczny

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2023

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R. 99, nr 12

323--326

EN

The article presents one of the aspects of the construction work of the device being created, i.e. the arrangement of the elements generating the magnetic field. When constructing the device, first of all, their arrangement is taken into account due to the position in the electrical diagram of the device, the method of power supply, and the distribution of signals. The article presents one aspect of the interaction of these elements, taking into account the mutual magnetic and thermal interactions.

PL

W artykule przedstawiono jeden z aspektów pracy konstrukcyjnej przy tworzonym urządzeniu – rozmieszczenia elementów generujących pole magnetyczne. Przy konstrukcji urządzenia w pierwszej kolejności bierze się pod uwagę ich rozmieszczenie ze względu na pozycję w schemacie elektrycznym urządzenia, sposób zasilania, rozprowadzenie sygnałów. Artykuł przedstawia sposób analizy jednego z aspektów wzajemnego oddziaływania tych elementów uwzględniających wzajemny wpływ pola magnetycznego i warunków termicznych.

8

The study of water reconditioning using magnetic field for plant industry

Poungprakhon Nattakun, Thongsopa Chanchai, Santalunai Samran, Thosdeekoraphat Thanaset, Santalunai Nuchanart, Chaipanya Pichaya

Przegląd Elektrotechniczny

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2023

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R. 99, nr 7

59--64

EN

This paper studies the growth of plants resulting from the use of magnetic-treated water. The emitter is designed by using a PVC pipe with inductance coils for inducting magnetic wave, divided into 5 types are one winding induction coil, two winding induction coils in the same direction, two winding induction coils in alternate directions, four winding induction coils in the same direction, and four winding induction coils in alternate directions. The simulation results are simulated by using CST Microwave Studio to analyze the magnetic field distribution that has an effect on the water. In addition, the five prototypes of inductance coils on pipe are constructed to be tested by watering real plants. When 40 liters of water flowed through the proposed pipe that surrounded by a magnetic field for 10, 30, and 60 minutes. It was found that the magnetic field generated by the four winding induction coils in alternate directions results in a transformation of water suitable for plant growth with 35.58 %, compared to the growth of plants grown by watering the elder does not pass through the magnetic field.

PL

W niniejszej pracy zbadano wzrost roślin w wyniku stosowania wody uzdatnionej magnetycznie. Emiter jest zaprojektowany przy użyciu rury PVC z cewkami indukcyjnymi do indukowania fali magnetycznej, podzielony na 5 typów to jedna cewka indukcyjna uzwojenia, dwie cewki indukcyjne uzwojenia w tym samym kierunku, dwie cewki indukcyjne uzwojenia w naprzemiennych kierunkach, cztery uzwojenia cewki indukcyjne w w tym samym kierunku i cztery uzwojenia cewek indukcyjnych w przeciwnych kierunkach. Wyniki symulacji są symulowane za pomocą CST Microwave Studio do analizy rozkładu pola magnetycznego, które ma wpływ na wodę. Ponadto skonstruowano pięć prototypów cewek indukcyjnych na rurze, które można przetestować poprzez podlewanie prawdziwych roślin. Kiedy 40 litrów wody przepłynęło przez proponowaną rurę, otoczono ją polem magnetycznym przez 10, 30 i 60 minut. Stwierdzono, że pole magnetyczne generowane przez cztery uzwojenia cewek indukcyjnych w naprzemiennych kierunkach powoduje przemianę wody odpowiedniej do wzrostu roślin o 35,58%, w porównaniu do wzrostu roślin uprawianych przez podlewanie bzu czarnego nie przechodzącego przez pole magnetyczne.

9

Evaluation of the influence of the skin effect on the maximum efficiency of the WPT system

Stankiewicz Jacek Maciej

Przegląd Elektrotechniczny

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2023

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R. 99, nr 1

73--79

EN

The article presents the influence of the skin effect on the maximum possible efficiency in the developed periodic Wireless Power Transfer (WPT) systems. The presented periodic WPT system allows for the simultaneous supply / charging of many low-power receivers. The analysis was performed based on the two proposed methods, i.e. analytical and numerical. The analytical solution of the transmitting-receiving system takes into account the parameters calculated based on analytical equations concerning the influence of magnetic couplings, structure geometry and loads. A numerical solution was also proposed, which allows the number of degrees of freedom to be reduced by applying periodic conditions. In order to verify the proposed methods and check the influence of the skin effect on the efficiency of the WPT system, calculations and analysis were performed for models that took into account the variability of the number of turns, the distance between the transmitting and receiving coils, and the frequency of the energy source. The results prove that taking into account the skin effect in the proposed low-power WPT systems reduces the efficiency of the system by up to 8%

PL

W artykule przedstawiono wpływ efektu naskórkowości na maksymalną możliwą do uzyskania sprawność w opracowanych periodycznych układach Wireless Power Transfer (WPT). Zaprezentowany periodyczny układ WPT pozwala na jednoczesne zasilanie/ładowanie wielu odbiorników małej mocy. Analiza przykładowych wariantów została wykonana na podstawie zaproponowanych dwóch metod, tj. analitycznej i numerycznej. Rozwiązanie analityczne układu nadawczo-odbiorczego, uwzględnia parametry obliczone na podstawie równań analitycznych dotyczących wpływu sprzężeń magnetycznych, geometrii konstrukcji i obciążeń. Zaproponowano również rozwiązanie numeryczne, które pozwala na redukcję liczby stopni swobody poprzez zastosowanie warunków periodycznych. W celu weryfikacji zaproponowanych metod i sprawdzenia wpływu efektu naskórkowości na sprawność układu WPT wykonano obliczenia i analizę dla modeli, w których uwzględniono zmienność liczby zwojów, odległość między cewką nadawczą i odbiorczą oraz częstotliwość źródła energii. Wyniki dowodzą, że uwzględnienie efektu naskórkowości w zaproponowanych układach WPT małej mocy powoduje zmniejszenie sprawności układu nawet o 8%.

10

Impact of orthodontic adhesive magnets on the mechanical properties and degree of conversion of a photopolymerized orthodontic adhesive

Al-Hayali Saud Khalil, Abed Mazin Ahmed, Al Qassar Sarmad Salih

Ochrona przed Korozją

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2023

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nr 10

329--334

EN

The purpose of this study was to calculate the effects of magnetic field (MF) on the degree of conversion (DC%) and mechanical properties of a photopolymerized orthodontic adhesive. In this investigation, Vega Ortho UV orthodontic adhesive was employed. The applied magnetic field had varying intensities (fixed at 0.01 T, 0.03 T, 0.05 T, 0.1 T, 0.15 T, and 0.2 T and a duration of 5 minutes) and a fixed frequency of 50 Hz. Vickers microhardness and DC% were investigated utilizing the specimens, which were created using circular molds and prepared for compression strength (CS) testing in accordance with ISO 4049. To evaluate DC% before and after MF exposure, Fourier-transform infrared spectroscopy (FTIR/ ATR) was performed. A microhardness tester was used to quantify the samples’ initial VHN while subjecting them to a 500 g load for 15 seconds. After that, properties were evaluated. With the aid of scanning electron microscopy (SEM), the surfaces were evaluated. The one-way analysis of difference and Tukey significant difference tests were used to evaluate the data. Analyses of statistical data showed that DC% tends to rise up to 0.05 T. When compared to the control, VHN and compression strength were considerably decreased after 0.03 T MF (p ≤ 0.05). However, there was a significant difference between the VHN and CS as their values increased with increasing magnetic field intensity. The surfaces of the Vega Ortho were deteriorated, as shown by SEM scans. It was found that the effect of the magnetic field caused changes in the physical and chemical properties.

PL

Celem badania było określenie wpływu pola magnetycznego (MF) na stopień konwersji (DC%) i właściwości mechaniczne fotopolimeryzowanego kleju ortodontycznego. W badaniu zastosowano klej ortodontyczny Vega Ortho UV. Zastosowane pole magnetyczne miało różne natężenia (0,01 T, 0,03 T, 0,05 T, 0,1 T, 0,15 T i 0,2 T przez 5 minut) i stałą częstotliwość 50 Hz. Mikrotwardość Vickersa i DC% ustalono z wykorzystaniem próbek, które zostały wykonane przy użyciu okrągłych form i przygotowane do badania wytrzymałości na ściskanie (CS) zgodnie z normą ISO 4049. Do oceny DC% przed ekspozycją na działanie pola magnetycznego i po niej wykorzystano spektroskopię w podczerwieni z transformacją Fouriera (FTIR/ATR). Do ilościowego określenia początkowej wartości VHN próbek użyto mikrotwardościomierza, poddając je obciążeniu 500 g przez 15 sekund. Następnie dokonano oceny właściwości. Ocenę powierzchni przeprowadzono za pomocą skaningowej mikroskopii elektronowej (SEM). Dane poddano jednokierunkowej analizie różnic i testowi istotnej różnicy Tukeya. Analizy danych statystycznych wykazały, że DC% ma tendencję do wzrostu do poziomu 0,05 T. W porównaniu z próbką kontrolną wartości VHN i wytrzymałości na ściskanie uległy znacznemu zmniejszeniu po oddziaływaniu 0,03 T MF (p ≤ 0,05). Istniała jednak znacząca różnica między VHN i CS, ponieważ ich wartości rosły wraz ze wzrostem natężenia pola magnetycznego. Powierzchnie Vega Ortho uległy degradacji, jak wykazały skany SEM. Stwierdzono, że wpływ pola magnetycznego spowodował zmiany właściwości fizykochemicznych.

11

The experimental study of the effect of magnetically sensitive elastomers on oil recovery of reservoirs containing high-viscosity oils

Mustafayeva Rena E.

Nafta-Gaz

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2023

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R. 79, nr 2

110--113

EN

In world practice, low-viscosity oil accounts for the main share of production. As the development progresses, the share of high-viscosity oil in the total balance increases year on year. The growing unused reserves of high-viscosity oil oblige researchers to solve the issue of developing these reserves, which is an important task for the oil industry. Studies have been carried out to increase oil recovery during the development of oil reservoirs containing high-viscosity oil by pumping a solution of magnetically active polymer, namely silicone oligomer, the matrix of which contains 5–25% Fe+3 ions, treated with a constant transverse magnetic field with a strength of H = 51740 A/m. A mixture of 90% by weight of quartz sand and 10% by weight of bentonite clay, with a permeability of k = 1.4 D, was used as a reservoir model. The high-viscosity oil model consisted of St-45 aviation oil. A silicone oligomer of 159–360 brand was used as a matrix with an operating temperature range of 60°C to +300°C, into which particles of gamma-Fe2O3 Nano powder with a size of 0.5 nm are introduced, with a degree of filling of the matrix of 5–25% by volume of Fe. Magnetization saturation is 80 emu/g, residual magnetization is 460 emu/g, and coercive force is 670 Oh. Validation of the proposed method was carried out by physical modeling of the process of displacement of high-viscosity oil with a magnetic elastomer on a laboratory installation. The oil recovery coefficient was calculated according to a wellknown method. The use of magnetically sensitive polymer can be an effective method of developing heavy oil fields. For each heavy oil field, taking into account its specifics (reservoir properties of the rock, physicochemical properties of oil, etc.), an appropriate magnet active polymer is selected. As the experimental results show, the best indicator of the oil recovery coefficient is achieved at 65%, compared with 48% of recovery in the absence of magnetic field exposure.

PL

W praktyce światowej główną część produkcji stanowią ropy o niskiej lepkości. W miarę postępu rozwoju udział rop o dużej lepkości w ogólnym bilansie rośnie z roku na rok. Rosnące niewykorzystane zasoby ropy naftowej o wysokiej lepkości obligują badaczy do rozwiązania kwestii zagospodarowania tych zasobów, co jest ważnym zadaniem dla przemysłu naftowego. W czasie zagospodarowania złóż ropy naftowej o dużej lepkości prowadzone były badania nad zwiększeniem wydobycia ropy poprzez tłoczenie roztworu magnetycznie aktywnego polimeru, jakim jest oligomer silikonowy, którego matryca zawiera 5–25% jonów Fe+3, poddanego działaniu stałego poprzecznego pola magnetycznego o natężeniu H = 51740 A/m. Jako model złoża zastosowano mieszaninę: 90% mas. piasku kwarcowego i 10% mas. glinki bentonitowej, o przepuszczalności k = 1,4 D. Modelem ropy o dużej lepkości był olej lotniczy St-45. Jako matrycę o zakresie temperatur pracy od 60°C do +300°C zastosowano oligomer silikonowy marki 159–360, do którego wprowadzone zostały cząsteczki nanoproszku gamma-Fe2O3 o rozmiarach 0,5 nm, a stopień wypełnienia matrycy jest w zakresie 5–25% obj. Fe. Nasycenie magnetyczne wynosi 80 emu/g, namagnesowanie szczątkowe wynosi 460 emu/g, a siła koercji wynosi 670 Oh. Walidację proponowanej metody przeprowadzono poprzez fizyczne modelowanie procesu wypierania oleju o dużej lepkości elastomerem magnetycznym w instalacji laboratoryjnej. Współczynnik odzysku oleju obliczono według znanej metody. Zastosowanie magnetycznie czułego polimeru może być skuteczną metodą zagospodarowania złóż ciężkich rop. Dla każdego złoża ciężkiej ropy naftowej, biorąc pod uwagę jego specyfikę (właściwości skały zbiornikowej, właściwości fizykochemiczne ropy itp.), dobierany jest odpowiedni polimer magnetycznie aktywny. Z eksperymentu wynika, że najlepszy współczynnik odzysku oleju osiągnięto na poziomie 65%, w porównaniu z 48% odzysku przy braku ekspozycji na pole magnetyczne.

12

Establishing and characterizing a permanent magnet system for the prototype of NIS's Kibble balance

Emira Sayed, Shaaban E. R., Rashad M. M., Gelany Shaker A.

Metrology and Measurement Systems

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2023

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Vol. 30, nr 1

3--16

EN

The Kibble balance experiment is used to redefine the kilogram as a unit of mass based on the Planck constant. To demonstrate and understand the basic principle of the Kibble balance, the National Institute of Standards (NIS)-Egypt has constructed a prototype Kibble balance that can measure gram-level masses with 0.01% relative uncertainty. Through the construction of this prototype, the challenges can be studied and addressed to overcome the weaknesses of NIS’s prototype. This study presents the design and construction of the prototype Kibble balance. It also focuses on the design and performance of the magnetic system, which is a crucial element of the Kibble balance. Analytical modeling and finite element analysis were used to evaluate and improve the magnet system. Several other aspects were also discussed, including the yoke’s material and enhancing the magnetic profile within the air gap of the magnet system. Over a vertical distance of 30 mm inside the air gap, the magnetic flux density was found to be 0.3 T, and the uniformity was found to be 8 x 10-5.

13

An Analysis of the Prospects of the Use of Magnetic Water Treatment in Foundry Engineering

Dan Leonid, Trofimova Larysa

Journal of Casting & Materials Engineering

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2023

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Vol. 7, no. 2

22--26

EN

Scientists are currently focused on creating technologies that produce positive results without affecting the environment. One such technology is magnetic water treatment. In this paper, an analytical review of publications devoted to the application of magnetic treatment of water in various branches of engineering, agriculture, and medicine is carried out. Current views on the structure of water molecules, as well as the theories explaining the influence of the magnetic treatment of water on its properties, are reviewed. The results of studies of the influence of water treated by a magnetic field on the properties of molding sand are analyzed, including those in which the authors of the article took part. It is shown that the magnetic treatment of still water can increase the green strength of the molding sand containing this water from 0.035 to 0.052 MPa, and that of water in motion to 0.075 MPa. Thanks to this, the amount of binder in the molding sand can be reduced. It is concluded that the use of magnetically treated water in foundries is promising.

14

Magneto-thermo-piezo-elastic wave in an initially stressed rotating monoclinic crystal in a two-temperature theory

Yadav Anand Kumar

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 3

127--158

EN

This research problem is an investigation of wave propagation in a rotating initially stressed monoclinic piezoelectric thermo-elastic medium under with the effect of a magnetic field. A two-temperature generalized theory of thermo-elasticity in the context of Lord-Shulman’s theory is applied to study the waves under the magnetic field. The governing equations of a rotating initially stressed monoclinic piezoelectric thermo-elastic medium with a magnetic field are formulated. This research problem is solved analytically, for a two-dimensional model of the piezo-electric monoclinic solid, and concluded that there must be four piezo-thermoelastic waves, three coupled quasi waves (qP (quasi-P), qT (quasi-thermal), and qSV (quasi-SV)) and one piezoelectric potential (PE) wave propagating at different speeds. It is found that at least one of these waves is evanescent (an evanescent wave is a non-propagating wave that exists) and that there are therefore no more than three bulk waves. The speeds of different waves are calculated and the influence of the piezoelectric effect, two-temperature parameter, frequency, rotation, and magnetic field on phase velocity, attenuation coefficient, and specific loss is shown graphically. This model may be used in various fields, e.g. wireless communications, signal processing, and military defense equipment are all pertinent to this study.

15

Magnetic effects on surface waves in a rotating non-homogeneous half-space with grooved and impedance boundary characteristics

Anya A. I., Nwachioma C., Ali H.

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 4

26--42

EN

Investigation on the Mathematical modeling of waves in a rotating grooved and impedance boundary of a non-homogeneous fibre-reinforced solid half‐space under the influence of magnetic field and mechanical force is envisaged. We derived analytically, the dynamical equations for the rotating grooved and impedance boundary of the non-homogeneous fibre-reinforced solid under the influence of magnetic fields and mechanical force. Harmonic solution method of wave analysis is utilized. This is such that the component of displacements and stresses are developed and studied after employing dimensionless parameters in the equations of motion. Numerical computations are presented in graphical form by using Mathematica Software for a particular chosen material. We observed that the combined grooved, magnetic fields, impedance boundary etc. physical parameters, have remarkable effects on the material. A decrease in horizontal impedance yielded maximum amplitudes of displacements and stresses of the waves on the fibre-reinforced medium. The mechanical force and rotation of the medium induced increased behaviors to the amplitudes of displacement and stress components of the wave on the solid medium. Thus, this work should be of great importance in studies involving seismology and seismic Mechatronics solution for stress-wave generation in non-homogeneous materials.

16

Substrates with different magnetic properties versus iron-nickel film electrodeposition

Białostocka Anna M., Klekotka Marcin, Klekotka Urszula, Żabiński Piotr R., Kalska-Szostko Beata

Chemistry-Didactics-Ecology-Metrology

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2023

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R. 28, NR 1-2

157--170

EN

The hereby work presents the iron-nickel alloys electroplated on the different metallic substrates (aluminium, silver, brass) using galvanostatic deposition, with and without presence of the external magnetic field (EMF). The films were obtained in the same electrochemical bath composition - mixture of iron and nickel sulphates (without presence of additives) in the molar ratio of 2 : 1 (Ni : Fe), the electric current density (50.0 mA/cm2), and the time (3600 s). The mutual alignment of the electric (E) and magnetic field (B) was changeable - parallel and perpendicular. The source of EMF was a set of two permanent magnets (magnetic field strength ranged from 80 mT to 400 mT). It was analysed the surface microstructure, composition, morphology, thickness and the mechanical properties (roughness, work of adhesion). The surface morphology and the thickness of films were observed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). The elemental composition of all FeNi films was measured using Wavelength Dispersive X-Ray Fluorescence (WDXRF). The crystalographic analysis of the deposits was carried out by X-Ray Diffraction. Depending on the used substrate, modified external magnetic field orientation influenced the tribological and physio-chemical properties of the deposited layers. The diamagnetic substrates and EMF application reduced the FeNi thickness and the average crystallites size, in contrast to the paramagnetic substrate. Parallel EMF increased the value of the tribological parameters for CuZn and Ag but decreased for Al. The content of FeNi structure was rising in the case of diamagnetic substrate and the dependence was opposite on the paramagnetic substrate.

17

Oddziaływanie elektromagnetyczne linii przesyłowych 400 kV na środowisko – analiza i metody jego redukcji

Tarko Rafał, Gajdzica Jakub, Nowak Wiesław

Śląskie Wiadomości Elektryczne

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2022

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Nr 5 (143)

11--16

PL

Celem artykułu jest analiza możliwości redukcji szerokości stref oddziaływania pola elektrycznego, poprzez zmianę parametrów projektowych linii elektroenergetycznych, określających przestrzenne rozmieszczenie jej przewodów. Analizę tę przeprowadzono z zastosowaniem opracowanych i zweryfikowanych eksperymentalnie modeli do wyznaczania pola elektrycznego w otoczeniu linii. Modele obliczeniowe wykorzystano do badań szerokości stref oddziaływania pola elektrycznego jedno- i dwutorowych linii elektroenergetycznych 400 kV. Badania potwierdziły możliwość znacznej redukcji szerokości stref oddziaływania pola elektrycznego poprzez odpowiedni wybór kluczowych parametrów projektowych i konstrukcyjnych linii. Otrzymane wnioski słuszne są nie tylko dla linii 400 kV, ale także wskazują na kierunki zmian parametrów linii o innych napięciach znamionowych.

EN

The aim of this paper is to analyze the possibilities of reducing the width of electric field influence zones by changing the design parameters of power lines and defining the spatial distribution of its conductors. This analysis was carried out using the developed and experimentally verified models for determining the electric field. The computational models were used to analyze the width of the electric field influence zones of single and double circuit 400 kV power lines. The analyses confirmed that the width of the electric field influence zones can be significantly reduced if the most important design and construction parameters of the line are properly selected. The obtained conclusions are valid not only for 400 kV lines, but also set directions to follow when changing the parameters of high voltage transmission lines of other rated voltages (above 100 kV).

18

Magnetic fields in the vicinity of high-voltage power lines, and optimisation of conductor arrangement

Kostyszyn Roman, Miśków Dominik

Scientific Journal of Gdynia Maritime University

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2022

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nr 123

66--78

EN

This paper presents calculations of the distribution of the magnetic fields generated by the current in phase conductors of overhead high-voltage power lines. The calculations are made for the area between the line paths and the terrain, with a particular focus on the area near the ground, important from the standpoint of humans present there, temporarily or permanently. Magnetic field distribution is determined for different arrangements of the phase conductors and line circuits, which are related to tower design. Minimum magnetic field value expressed in A/m and cost of building the power line are the optimisation criteria.

19

Wpływ stymulacji zmiennym polem magnetycznym nasion pszenicy o różnym przeznaczeniu technologicznym

Jakubowski Tomasz, Syrotyuk Serhiy, Lopushniak Vasyl, Atilgan Atilgan

Przegląd Elektrotechniczny

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2022

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R. 98, nr 5

38--42

PL

Celem pracy było określenie reakcji nasion pszenicy (Triticum aestivum L.) o różnym przeznaczeniu technologicznym na zmienne pole magnetyczne. W doświadczeniu wykorzystano stanowisko z układem RC OSCILLATOR TYPE G502 generującym sygnały sinusoidalne i prostokątne o częstotliwościach w zakresie 0-100 Hz. Stosowano wielkość indukcji magnetycznej pola: 10, 40 i 70 mT oraz czas ekspozycji nasion: 10, 600 i 1800 s. Wykazano istotny wpływ zmiennego pola magnetycznego na niektóre parametry ontogenetycznych roślin.

EN

The aim of the study was to determine the reaction of wheat (Triticum aestivum L.) seeds for various technological purposes to a variable magnetic field. In the experiment, a stand with the RC OSCILLATOR TYPE G502 system generating sinusoidal and square signals with frequencies in the range of 0-100 Hz was used. The magnitude of the magnetic field induction was used: 10, 40 and 70 mT and the seed exposure time: 10, 600 and 1800 s. A significant influence of the alternating magnetic field on some ontogenetic parameters of plants was demonstrated.

20

Influence of the coil winding direction on the efficiency of Wireless Power Transfer Systems

Stankiewicz Jacek Maciej

Przegląd Elektrotechniczny

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2022

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R. 98, nr 4

148--153

EN

The article presents the results of numerical and analytical analysis of the Wireless Power Transfer System (WPT). The system consists of flat, square coils. Two WPT systems were considered: periodic and aperiodic. In the aperiodic arrangement, adjacent coils had their turns wound in the opposite direction. The influence of the winding direction, the number of turns and the distance between the coils on the efficiency of the WPT system was compared. The analysis covered a wide frequency range from 100 kHz to 1000 kHz. The results obtained with both proposed methods were consistent, which confirmed the correctness of the assumptions made. In periodic and aperiodic models, higher efficiency was achieved for a higher number of turns. The proposed aperiodic models of the WPT system show a higher system efficiency than periodic models by up to 40%. The proposed WPT system can be used for simultaneous charging of many sensors located e.g. in walls.

PL

W artykule przedstawiono wyniki analizy numerycznej i analitycznej Systemu Bezprzewodowego Przesyłu Mocy (WPT). System składa się z płaskich cewek kwadratowych. Rozpatrzono dwa układy WPT: periodyczny i aperiodyczny. W układzie aperiodycznym sąsiednie cewki miały nawinięte zwoje w przeciwnym kierunku. Porównano wpływ kierunku uzwojenia, liczby zwojów oraz odległości między cewkami na sprawność układu WPT. Wyniki uzyskane obiema zaproponowanymi metodami były zgodne, co potwierdziło słuszność przyjętych założeń. Analiza została przeprowadzona w szerokim zakresie częstotliwości (100 - 1000 kHz). W modelach periodycznych i aperiodycznych wyższą sprawność uzyskano dla większej liczby zwojów. Zaproponowane aperiodyczne modele systemu WPT wykazują wyższą sprawność układu niż modele periodyczne nawet o 40%. Proponowany system WPT może służyć do jednoczesnego ładowania wielu czujników umieszczonych np. w ścianach.