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The layers were prepared by ion beam assisted deposition of iridium and platinum onto AVCarb® Carbon Fiber Paper P50 electrocatalyst supports for the production of diffusion layers of the membrane-electrode assemblies of low temperature fuel cells with polymer electrolyte membrane. Formation of the layers in the ion beam assisted deposition mode, by means of the deposition of metal and mixing of precipitating layer with the substrate by the accelerated (U=10 kV) ions of the same metal, was performed. In this process neutral fraction of metal vapour and ionized plasma of vacuum pulsed electric arc discharge were used. The investigations of morphology and composition of layers were carried out by the scanning electron microscopy, energy dispersive X-ray microanalysis, wave dispersive X-ray fluorescence analysis, and the Rutherford backscattering spectrometry methods. It was established that the obtained catalytic layers contain atoms of the deposited metals and substrate material as well as impurity oxygen atoms. The surfaces contain also metal inclusions of several micrometer size which arise from the precipitation of deposited metal droplets from the arc discharge of an ion source. The content of iridium and platinum atoms in the layers is ≈2×10¹ cm-2; the concentration of the deposited metals equals about several atomic percent. [ABSTRACT FROM AUTHOR]

Electronics devices that facilitate our daily life are rapidly reaching into almost every area of our lives nowadays. Wireless communication using electromagnetic waves is preferred rather than wired communication due to the physical hardship in communication of these devices with each other. Electromagnetic waves provide communication between transmitter and receiver and also reach to unintended targets except receiver. If electromagnetic wave reaches an electronics circuit, it will cause the formation of undesired parasitic currents and the destruction of electronic circuits defined as electromagnetic interference. If electromagnetic wave reaches the tissue environment, it will change the structure and arrangement of cells at the molecular level depending on the wave frequency and power. As a result of long term exposure, it may cause cancer and its derivatives in living organism due to changes in cell structure. As seen in the electromagnetic studies, it may cause irreversible damage to living organism exposed to electromagnetic waves. Therefore, the study carried out will have an effect especially protection of living species against the electromagnetic wavelength's harmful effects. In this study, it is aimed to be performed of the mineral doped waste paper-based board design which will absorb electromagnetic waves that imposed nowadays in any environment. Experimental results show that electromagnetic shielding effectiveness of waste paper fibers with mineral powders (BaSO4, C, Fe2O3) is acceptable levels. [ABSTRACT FROM AUTHOR]

In this study, cement composites were produced with CEN reference sand, cement, water, and waste paper. Waste paper were used as partial replacement 0-0.50 ratios of sand weight which was tagged as CK and WPCK, and the cement-to-sand ratio was kept constant at 1:3. Mix design was based on the standard of TS EN 196-1. The infrared spectra were recorded by accumulating 64 scans each in 4000-400 cm-1 range with a resolution of 4 cm-1 with KBr pellets at room temperature. The linear attenuation coefficients of composites were measured using the gamma spectrometer system containing NaI(Tl) detector. The measurements were performed at 1173 and 1332 keV, which was obtained from 60Co radioactive sources. [ABSTRACT FROM AUTHOR]

In this study, styrene(St)/2-ethyl hexyl acrylate(2-EHA) based surface sizing materials were developed with four different cationic monomers (CM), namely diallyldimethyl ammonium chloride (DADMAC), [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MATMAC), [3-(methacryloylamino) propyl]-trimethyl ammonium chloride (MAPTAC), (viniylbenzyl) trimethyl-ammonium chloride (VBTMAC). Ternary polymerization was realized with emulsion polymerization, by using 2,2'-azobis (2-methylpropionamidine) dihydrochloride (A) as initiator. Thermal properties of the synthesized terpolymers were determined with differential scanning calorimeter and thermal gravimetric analysis. Differential scanning calorimeter results showed that glass transition temperature (Tg) values of polymers were not dependent on the types of cationic monomers, and were found about 44-45 °C. Ion exchange capacities of the terpolymers were determined. The latexes produced were used as sizing materials for paper surface treatment. Then critical surface properties of the papers sized such as water resistance (Cobb value) and contact angle were measured. It was found that the best, i.e. the lowest Cobb results were obtained when MATMAC and MAPTAC cationic monomers were used in terpolymers. [ABSTRACT FROM AUTHOR]

In this study, styrene 70 wt.%-butyl acrylate 30 wt.% copolymer-based surface-sizing materials were synthesized using semi-batch emulsion polymerization and applied on the paper. Four different emulsifiers, with different ethylene oxide numbers, at ratios of 10%, 7% and (2, 2'-azobis (2-methylpropionamidine) dihydrochloride (A)) as initiator were used for emulsion polymerization. Eight different copolymers were synthesized. Synthesized copolymers were used as surface sizing agents for the paper surface. Ion exchange capacity, pH, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal gravimetric analysis were used for the characterization of the copolymer properties. Contact angle measurements, Cobb test, and scanning electron microscopy analysis were carried out to determine the surface properties of the paper samples. Presence of copolymer formations was proven with the Fourier transform infrared analysis. Contact angle measurements of the copolymer sized paper surface have shown hydrophobic behaviour in samples, with the exception of E-3/7/A sample. The lowest Cobb value was observed for E-2/7/A sample. The highest thermal stability was also observed for E-2/7/A sample. The scanning electron micrographs show that the paper loses its fibrous structure and it is seen that the copolymer adheres to the fibrous tissue. [ABSTRACT FROM AUTHOR]

"Graphene paper" prepared by new proprietary method involving high pressure and high temperature treatment in the reduction process show new possibilities in this area. Different phase content: multilayer and single layer graphene stacks recorded in this study for RGO samples are accompanied by the specific electric and optical parameters. We have found that process temperatures above 900 °C play crucial role in structural and other properties. For the process temperature around 2000°C we found the onset of the graphitization in the samples. [ABSTRACT FROM AUTHOR]

Bismuth ferrite belongs to magnetoelectric compounds which join, in the same crystal phase, two mutually excluding order parameters like magnetic and ferroelectric. In case of BiFeO3 both of these transition temperatures are considerably above room temperature what is important form the point of view of applications. In this paper electronic band structure calculations are presented. In the calculations, hybrid exchange interaction potential is applied, which gives the possibility to obtain correct insulating character of the compound without application of arbitrary Hubbard U parameter. The calculated densities of electronic states and magnetic properties are described. [ABSTRACT FROM AUTHOR]

The paper focuses on an extension of the GRUCAD hysteresis model. The extension relies on the re- placement of the Langevin function with a more general Brillouin function in an equation describing the anhysteretic curve. The proposed approach allows one to obtain better fitting capabilities for anisotropic soft magnetic materials, as demonstrated by the example of hysteresis curves of grain-oriented electrical steel. [ABSTRACT FROM AUTHOR]

In this paper the results of carbon nanoparticle deposition on metal surface by impulse plasma deposition method (IPD) are presented. Graphite plates were used as sources of dust particles and copper substrates for their deposition. During the experimental work spherical nanocarbon particles with dimensions of 20-180 nm were obtained on the copper substrate and copper particles forming dendritic nanostructures on the substrate surface where their average size was 400 nm. [ABSTRACT FROM AUTHOR]

This paper focuses on two models used for the determination of power loss components in steel samples under dynamic magnetizing conditions. The considered models differ in their approach as far as the possibility of distinguishing bulk and localized eddy currents is concerned. Two samples of non-oriented electrical steel differing in silicon weight contents are the subject of experiments. A comparison of the obtained results, as well as their discussion, is given in the paper. [ABSTRACT FROM AUTHOR]

In weak magnetic fields, there are changes in the arrangement of atoms, which are otherwise called magnetic relaxations. The exact phenomenon that will be investigated in this paper concerns the disaccomodation of magnetic susceptibility, which is one of the most frequently observed effects of magnetic lag. During this magnetic delay, there is a reorientation of the axes of pairs of atoms corresponding to two different energy levels. This energy is related to the energies of exchange and spin-orbit coupling. The paper presents the results of magnetic susceptibility disaccomodation and describes its influence on the relaxation time matching spectrum. [ABSTRACT FROM AUTHOR]

Understanding the complex physical phenomena involved in the casting process simulation requires continuous and complementary research to improve mathematical modelling. The paper presents a mathematical model and numerical simulations of the solidification process of a cylindrical casting, taking into account the filling of the mould cavity with liquid metal and feeding the casting through the riser during solidification. The basic mathematical model that considers only thermal phenomena is often insufficient to analyse the metal solidification process. Therefore, more complex models are formulated that include coupled thermal and flow phenomena. The mathematical description then consists of the system of Navier-Stokes differential equations, the equations of the continuity of flow and energy. Such a mathematical model was used in the paper because the mutual dependence of thermal and flow phenomena has a significant impact on the solidification process. The finite element method was used to solve the problem, and changes in thermophysical parameters were considered as a function of temperature. The impact of the riser shape on the effectiveness of feeding of the solidifying casting was also determined and an appropriate selection of the riser shape was made to obtain a casting without shrinkage defects, which was the aim of this work. [ABSTRACT FROM AUTHOR]

The process of radiological characterization involving all the systems, structures, equipment, and components resulting from the decommissioning of the VVR-S nuclear research reactor at the Horia Hulubei National Institute for Physics and Nuclear Engineering was a continuous journey marked by ongoing research, specialized training, and the accumulation of invaluable experience. Recognizing the significance of protecting the expertise gained during this effort, this paper aims to share several key insights collected from the radiological characterization process. In particular, the focus is placed on elucidating various methodologies and techniques utilized in gamma-ray spectrometry. The aim of delving into these specific aspects is to offer practical lessons that can serve as valuable guidance for future efforts in radiological characterization within similar contexts. Through the dissemination of these insights, it is hoped that the collective knowledge and expertise amassed during the radiological characterization of the VVR-S nuclear research reactor decommissioning can be effectively preserved and utilized for the benefit of future projects in the field. [ABSTRACT FROM AUTHOR]

In weak magnetic fields, there are changes in the arrangement of atoms, which are otherwise called magnetic relaxations. The exact phenomenon that will be investigated in this paper concerns the disaccomodation of magnetic susceptibility, which is one of the most frequently observed effects of magnetic lag. During this magnetic delay, there is a reorientation of the axes of pairs of atoms corresponding to two different energy levels. This energy is related to the energies of exchange and spin-orbit coupling. The paper presents the results of magnetic susceptibility disaccomodation and describes its influence on the relaxation time matching spectrum. [ABSTRACT FROM AUTHOR]

The present study is dedicated to the issue of the operation of flat plate solar collectors with different tube cross-sections and different absorbers. Here, the flow of the working medium is analyzed in order to assess the influence of the type of tube cross-section and the type of absorber on the thermal parameters of the installation. Numerical tests were carried out on full-scale simulations with the use of Ansys Fluent software. The analysis showed that the efficiency of the system can be significantly improved by installing an appropriate absorber system. The results also show that changing the thickness and type of material the absorber is made of has a large impact on the efficiency of the collector. In this paper, to describe the phenomenon in question and to verify the obtained data, a mathematical model based on fractional order differential calculus is proposed. After comparing the flow of the working medium through collectors with different tube cross-sections with different types of absorbers, it was shown that the best results were obtained for a collector with a circular cross-section of tubes and an absorber made of copper with a thickness of 0.5 mm. [ABSTRACT FROM AUTHOR]

In this paper, the results of studies on sub-micrometer planar structures used for aimed frequency-dependent electromagnetic radiation dissipation are presented. The proposed specific geometry of periodic parts of surface structures should enable the occurrence of phenomena related to selective reflectance and interference. The inner porous structure should lead to the formation of destructive interference of electromagnetic radiation and its dissipation. The investigated structures were irradiated by a Gaussian-type radiation source. The propagation was analyzed using the MEEP software package for electromagnetic simulation via the finite-difference time-domain method. The reflectance spectra were obtained by the Fourier transform of the response to the short pulse. The obtained results showed that the surface structures are mainly responsible for reflected electromagnetic spectrum composition, while the porous parts were responsible for thermal radiation dissipation. [ABSTRACT FROM AUTHOR]

The presented paper focuses on a problem of heat transfer in periodic surface structures. The periodic structure surfaces are the compound structures described by mathematical formulas that represent areas similar to porous structures. The interest in them surged recently due to increased possibilities of their production using additive manufacturing technology. Elements designed with the use of periodic surface structures seem to have such advantages as decreased weight or good general mechanical properties. The most famous example of the periodic surface structure is gyroid. The main goal of this paper is to evaluate the impact of convective heat transfer on the temperature distribution in periodic surface structures. There are some papers with numerical simulations on this topic but they usually exclude heat exchange with the environment. The simulations of heat transfer in the periodic structure surfaces are important because of the high energy flux required for additive manufacturing to work properly. Importantly, high energy flux results in large temperature gradients that can affect the quality of the obtained part in properties like porosity or residual stresses. The heat transfer simulations in this paper are conducted by solving the heat transfer equation accompanied by the proper boundary conditions using our authorial software, which implements solution obtained by the finite element method together with the task of generation of the periodic surface structure domain. [ABSTRACT FROM AUTHOR]

The purpose of the following paper is to compare the applicability of Rayleigh hysteresis model and Steinmetz law in the evaluation of power losses of selected soft magnetic materials under the influence of low magnetizing fields. Both approximations are relatively simple in terms of computational complexity, thus they seem to be appropriate for technical applications that do not require extensive knowledge of the physical properties of the material. The selected soft magnetic materials, i.e., steels and ferrites, in the form of toroidal cores, were investigated in low magnetizing fields with a computer-controlled hysteresisgraph system. Both considered models were applied to the obtained power loss characteristics. The quality of the description provided by each model was compared in terms of root-mean-square deviation and determination coefficient R², which allowed us to choose the more suitable approximation. [ABSTRACT FROM AUTHOR]

In this paper, the method for calculating losses in magnetic cores operating in a DC/DC power converter is experimentally verified for selected samples. The chosen method of calculating magnetic losses based on loss measurements under sinusoidal excitation is described, and the measurement process is discussed. The results of power loss measurements with a direct current bias for three different magnetic core materials, e.g., ferrite, nickel-iron-molybdenum alloy powder, and nanocrystalline, are presented. A quantitative determination of the deviations for the tested method is proposed, including the frequency dependence of the deviation distribution. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the spin–orbit coupling of F = 1 dipolar Bose–Einstein condensates in a quasi-one-dimensional trap by solving the mean field Gross–Pitaevskii equation. We focus on the two phases, ferromagnetic and antiferromagnetic. For the former, we find that the spin echo signal emerges gradually as the spin–orbit coupling strength increases, which favors miscibility in density profile. The dipolar interaction plays a tiny role in the spin dynamics process, the qualitative behavior remains almost unchanged. Nevertheless, for the antiferromagnetic phase, the physical picture greatly changes. The spin echo signal abruptly increases with the increase in spin–orbit coupling strength, and the density structure exhibits phase separation. With the emergence of dipolar interaction, the spin echo signal vanishes, and the evolution of the three components is ruleless. Meanwhile, the condensate deviates from the property of phase separation. Also, we analyze the effect of the number of atoms on spin dynamics. It is obvious that the reduction of atoms increases the number of spin echo signals for the ferromagnetic phase regardless of the nature of dipolar interaction. In addition, for the antiferromagnetic phase, such a decrease gives rise to the disappearance of the spin echo signal in the absence of dipolar interaction, and its influence is small when dipolar interaction is added. [ABSTRACT FROM AUTHOR]

A free-electron laser is a laser that has the same optical properties as a conventional laser, such as emitting beams of coherent electromagnetic radiation, which can reach high powers, but uses some very different principles of operation to form the beams. The chaotic motion of electrons causes a considerable decrease in the gain and efficiency of free-electron lasers. In this paper, the Hamiltonian of the dual-wiggler free-electron laser with and without axial guide magnetic field is constructed. Hamilton's equations of motion were derived exactly for both cases. The steady-state solution is also derived and investigated so that the initial conditions of the system are clear. The Poincaré surface-of-section maps were plotted after solving Hamilton's equations of motion numerically, where the chaotic behavior of the system was obvious when the axial field was included while the motion became regular and the Hamiltonian is integrable in the absence of the axial guide magnetic field. Regular orbits are observed clearly for large values of the axial field. [ABSTRACT FROM AUTHOR]

In this paper, a horizontal-type surface acoustic wave device based on electrode width control interdigital transducer/polymethylmethacrylate/54° Y --X LiNbO3 is proposed to achieve the removal of non-specific binding particles by Rayleigh waves and the detection of meningococcus by Love waves. It is proved that the surface acoustic wave force plays a leading role in the removal of non-specific binding, and the frequency of the acoustic wave also affects the removal effect. The advantage of electrode width control interdigital transducer lies not only in overcoming the shortcomings of bidirectional and focused interdigital transducers, but also in improving the utilization of acoustic waves and the sensitivity of the sensor. When non-specific binding particles are removed by Rayleigh waves, the Love wave sensor shows a sensitivity of 330 Hz/(ng/l'L) and a detection limit of 50 pg/µL for meningococcus. [ABSTRACT FROM AUTHOR]

Gas detection is vital for safety in important industrial and private sectors. Its major significance lies in its proactive risk mitigation, safeguarding lives and resources. In this paper, the focus is on the development of a gas sensor based on quartz crystal microbalance coated with a sensitive layer of zinc oxide (ZnO)--graphene nanocomposite for the detection of volatile organic compounds at room temperature. The incorporation of graphene or reduced graphene oxide is preferred in such applications due to their excellent electrical conductivity, chemical stability, and high surface area. These nanocomposites were synthesized using a chemical method via spray pyrolysis. Various techniques were employed to analyze the coated QCM electrode: contact angle measurements to assess surface wettability, Fourier transform infrared and energy-dispersive X-ray spectroscopy to investigate the composition of the coated electrode, and scanning electron and atomic force microscopies were used to study its surface morphology. These analyses provided valuable insights into the nanocomposite's interaction with the environment, composition, structure, and topography of the sensor's sensitive layer. To evaluate the sensor's sensitivity, the frequency shift (_f) of the coated QCM electrode is monitored when exposed to different gas concentrations of ethanol, toluene, chloroform, humidity, and formamide, ranging from 47 to 142 ppm. The frequency shift indicated the detected gas concentration. The results demonstrate good repeatability and reversibility, which are crucial indicators of a sensor's reliability. This reliability is essential for applications in environmental monitoring or industrial safety, where accurate gas detection is critical. [ABSTRACT FROM AUTHOR]

Since the foundation of the Institute of Physics, Polish Academy of Sciences (IF PAN) in 1953, semiconductor physics has been its main research activity. This short paper provides lists of (i) organizational milestones of "Jaszowiec" and (ii) invited talks presented by physicists of IF PAN at the "Jaszowiec" meetings. For a more in-depth discussion covering selected fields of IF PAN's activity and containing references to original papers, readers are delegated to a recent essay completed by the present author for the 100th anniversary of the Polish Physical Society (T. Dietl, Acta Phys. Pol. A 139, 355 (2021), systematically updated versions at arXiv:2103.07456). [ABSTRACT FROM AUTHOR]

Using a set of over 70.000 records from PLOS One journal consisting of 37 lexical, sentiment and bibliographic variables we perform analysis backed with machine learning methods to predict the class of popularity of scientific papers defined by the number of times they have been viewed. Our study shows correlations among the features and recovers a threshold for the number of views that results in the best prediction outcomes in terms of Matthew's correlation coefficient. Moreover, by creating a variable importance plot for random forest classifier, we are able to reduce the number of features while keeping similar predictability and determine crucial factors responsible for the popularity. [ABSTRACT FROM AUTHOR]

In the present paper, the theoretical and experimental investigation of the thermomagnetic properties of the LaFe11.0Co0.8Si1.2 alloys was conducted. The field dependences of magnetization in a wide range of temperatures were collected. Based on the thermomagnetic Maxwell's relation, the magnetic entropy change ΔSM was calculated. Moreover, temperature dependences of magnetization in a wide range of fields were simulated using the phenomenological model. The values of thermomagnetic properties, such as magnetic entropy change and refrigeration capacity, were calculated. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the dynamic properties of spin-orbit coupling spin-1 ferromagnetic Bose-Einstein condensates with different trap geometry. Our results are obtained in terms of the threecomponent Gross-Pitaevskii equation of mean-field theory. Two kinds of trap potential are discussed: isotropic and anisotropic. It is shown that the spin-exchange dynamics are greatly influenced by trap geometry. For the latter with weak spin-orbit coupling strength, we find that the three-component oscillation accelerates and some small difference emerges between component m = 1 and m = -1. With the increase in spin-orbit coupling strength, the three components reach almost the same population. In addition, the kinetic energy of the system changes within a small scope for strong spin-orbit coupling, as opposed to a constant value in an isotropic trap. The density distributions display that the stripe phase appears with the increase in spin-orbit coupling strength. The method of generating stripe structure is different from the ground state of ferromagnetic condensate. For isotropic trap, the spatial separation of top and bottom spin-orbit condensates in component m = 1 and m = -1 occurs at weak spin-orbit coupling, and square lattice appears at strong spin-orbit coupling. [ABSTRACT FROM AUTHOR]

The main goals of the FragmentatiOn Of Target experiment are the measurements of double-differential fragmentation cross-sections of light particles (Z < 10) in the energy range between 100-800 MeV/u, which is of interest for hadron therapy and space radioprotection applications. The results will fill the gap in experimental data in this range, which is important for improving the treatment planning systems in particle therapy and for enhancing the reliability of risk-assessment models for space radioprotection. Two different setups were designed for this scope, and data have already been taken in several campaigns. In this paper, an overview of the apparatus is described, focusing on the preliminary results of crosssection measurements obtained with a 16O beam at the GSI facility. [ABSTRACT FROM AUTHOR]

Molecular magnetism aims to design materials with unique properties at the molecular level, focusing on the systematic synthesis of new chemical compounds. In this paper, we propose an alternative route to engineer molecular magnetic materials through plasma irradiation. Our research indicates that the long-range magnetic order temperature in the three-dimensional {[MnII(H2O)2]2[NbIV(CN)8] x 4H2Ogn molecular ferrimagnet increases by 20 K after plasma treatment. The core structure of the compound does not reveal significant changes after plasma processing, as confirmed by the X-ray powder diffraction analysis. The observed results are attributed to the release of crystallized water molecules. The described procedure can serve as a viable approach to altering the magnetic properties of the molecular systems. [ABSTRACT FROM AUTHOR]

The paper presents the results of validating the model of anhysteretic magnetization curve of anisotropic soft magnetic materials utilizing the Boltzmann distribution of magnetic domain directions. It was confirmed that the editorial mistake in the original paper presenting the concept of anisotropic anhysteretic magnetization curve was reproduced in subsequent publications. Validation presented in the paper covers an anhysteretic magnetization curve model for magnetic materials with axial anisotropy and anisotropic grain-oriented electrical steels. However, the proposed correction of the model of the anisotropic anhysteretic magnetization curve can be extended to other types of anisotropy. [ABSTRACT FROM AUTHOR]

In this paper, phenomenological modeling and experimental studies were conducted to predict the magnetocaloric properties of the MnCoGe alloy. The temperature dependence of magnetization was measured and calculated using a simple phenomenological model. A good correlation between simulated and experimentally determined data was observed. The phenomenological model allowed us to reveal theoretical values of the magnetic entropy change, full width at half maximum of ASM vs T curve, and relative cooling power. [ABSTRACT FROM AUTHOR]

An introduction to the special issue of the journal is presented which features selected papers of the 2nd International Conference on Computational and Experimental Science and Engineering (ICCESEN).

The Majorana bound state can be realized in one-dimensional chain, in form of two well-localized and separated states at both ends of the chain. In this paper, we discuss the case when the potential is smeared at one end of the system. In our investigation, we assume the smearing in the form of a quadratic function of position. We show that the smearing potential leads to the emergence of extra in-gap states, and effectively decreases the local gap (around the smeared potential). The Majorana states are still preserved in the system, however, their localization depends on the smearing. Moreover, the symmetric localization of the Majorana states from both sides of the system is no longer preserved in the presence of the smearing potential. [ABSTRACT FROM AUTHOR]

The paper concerns problems related to controlling the properties of vibrating slender elements. The main mechanism that influences global mechanical features of the system is redistribution of the grains located inside the considered element. The dynamic properties of the investigated system can be controlled by external factors resulting in partial changes in grains redistribution. An application of special pneumatic system allows to change either stiffness or mass distribution (density) of the beam. Original experimental results are presented in the paper. It is confirmed that there is a significant and direct connection between the granular mass distribution and the dynamics of the system. The spectral vibration analyses were carried out for various particles redistribution cases. Additionally an initial approach to the modeling process is introduced. The continuous model of cantilever beam has been simplified to a discrete multi DOF system. The verification of experimental and numerical data revealed the satisfactory convergence. It is confirmed that there is a possibility to find such parameters of the system which allow to avoid dangerous resonant frequencies. [ABSTRACT FROM AUTHOR]

This paper considers the effect of compaction pressure on the shape of magnetization curves of soft magnetic composite cores compacted at different compaction pressures. Two versions of the phenomenological Takács T(x) model are taken into account. [ABSTRACT FROM AUTHOR]

This paper establishes a quantum rectangular heat engine model by applying finite-time thermodynamics. The working medium is countless particles trapped in a one-dimensional infinite potential well. Taking into account heat leakage between the system and the outside, expressions for thermal efficiency (η), dimensionless power (P), and dimensionless efficient power (Wep) of quantum rectangular heat engine are derived, and its optimal performance is studied. System performance P, η, and Wep are optimized firstly by taking the width ratio of the potential well as the optimization variable. The outcomes show that the relationship curve between P and η is a loop-shaped curve. With an increase in heat leakage coefficient, the optimal design range of the quantum rectangular heat engine becomes smaller. The relationship curve between the efficient power and width ratio of the potential well is parabolic-like. The relationship curve between Wep and η is a loop-shaped curve. The efficiency of the quantum rectangular heat engine at Wep max operating point is greater than that at Pmax operating point. Secondly, multi-objective optimization is applied with η, P, and Wep as optimization objectives by applying NSGA-II, and the optimal design scheme is achieved by applying TOPSIS, LINMAP, and Shannon entropy decision-making approaches. The smallest deviation index inferred by the Shannon entropy approach is 0.0269. The design scheme is closest to the ideal scheme. [ABSTRACT FROM AUTHOR]

For layered metamaterial devices, the reflection and transmission coefficients at an interface typically depend on the properties of the coupling between different layers. In this paper, we set out to engineer the reflection/transmission behaviour at boundaries to obtain desirable properties such as achieving total reflection and transmission. Based on the quantum graph formulation for modelling metamaterials developed in Sci. Rep. 12 (1), 18006 (2022), we tailor the interface reflection and transmission coefficients by patterning the boundary with resonant elements at each interface vertex. By tuning the internal lengths of the resonant elements, we demonstrate both minimization and maximization of the reflection coefficient via a scattering formulation. In addition, we present an interface set-up incorporating beyond-nearest-neighbour connections, which yields narrow-band transmission for certain angles only, creating an angular filtering interface. [ABSTRACT FROM AUTHOR]

The magnetisation process of magnetic materials is extremely important due to the potential applications of these materials. During the magnetisation process, a delay in the increase in magnetisation is observed when the magnetic field strength increases. This behaviour may be explained by the magnetic anisotropy of the studied material. The paper presents the results of research on primary magnetisation curves for magnetic alloys that exhibit soft-magnetic properties. The tested alloys are the so-called amorphous materials in which determining the preferred direction of magnetisation is difficult due to their structure. However, as our research indicates, it is in fact possible to distinguish directions of relatively easy and difficult magnetisation in amorphous materials, which implies that the phenomenon of magnetic anisotropy occurs in them. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the effect of circular-shaped microcylinders on the flow field around an airfoil, using time-resolved particle image velocimetry. The results show that microcylinders can significantly modify the flow pattern around the NACA 0012 airfoil. The optimal configuration of microcylinder-airfoil depends on the angle of attack and the position of the microcylinder. The obtained results have practical implications for the development of more efficient and sustainable aircraft designs and wind turbine blades. The paper presents a physical analysis of flow fields using streamlines and vorticity structures to illustrate mechanisms of flow control for improving the aerodynamic properties of the airfoil. Overall, this work provides new insights into the fundamental physics of flow control using microcylinders, including general physics and optics, with potential application in various contexts, such as aerodynamics, flow control, airfoil design, optical diagnostics, and particle image velocimetry techniques. [ABSTRACT FROM AUTHOR]

Studying the real structure of amorphous alloys is not an easy task and requires an appropriate scientific approach. Unlike crystalline materials, for which there is a precise description of the structure based on the structure of the unit cell, in amorphous materials it is not possible to identify it. The amorphous structure is often described as one big defect. Using the technique of Mössbauer spectroscopy, it is possible to study the structure of amorphous alloys and determine the degree of their order. The paper presents the results of Mössbauer tests for amorphous alloys in the state after solidification. The influence of a small change in the chemical composition on the probability of the occurrence of iron surroundings determining specific hyperfine field induction values was determined. [ABSTRACT FROM AUTHOR]

This paper reports on the characterization of Sn- and Al-doped zinc oxide thin film for potential ammonia gas detection. The sol-gel method has been used to deposit the dopant onto the glass substrate at an annealing temperature of 500° for three different doping concentrations, which are 0.5, 1.0, and 1.5 at.%. The method used to produce this thin film is sol-gel, as it is cheap, easy, and can be employed at low temperatures. The studies involve the investigation of the morphological structures and electrical and optical properties of doped ZnO. In terms of structural properties, scanning electron microscope images of Sn- and Al-doped ZnO change as the dopant concentration is increased. The doped thin film response and recovery towards 200 ppm of ammonia were observed and recorded. Both dopants show good gas sensing response. The recorded resistance reading suggests that Al is the superior dopant in gas sensing as it produces a low resistance reading of 230 Ω as opposed to 140 kΩ produced by Sn-doped ZnO thin film. [ABSTRACT FROM AUTHOR]

In this paper, the impact of the extinction coefficient on electromagnetic wave transmission in a quasione-dimensional thin superlattice structure is investigated. The system consists of several layers of optical materials with different densities, and the focus is put on the transmission of light through this arrangement. Using theoretical modeling via the transfer matrix method, it is found that the extinction coefficient significantly influences transmission properties. Furthermore, the impact of altering the extinction coefficient of specific layers on the overall transmission behavior is investigated through systematic variations of the extinction coefficient and exploration of how changes in the optical properties of individual layers influence the transmission spectrum and the emergence of transmission peaks and valleys. These results provide valuable insights into the design and optimization of superlattice structures for various applications, including optical devices and photonic systems enabling precise light control. [ABSTRACT FROM AUTHOR]

The paper presents a comprehensive investigation of the ultraviolet-filtration properties of a quasi-one-dimensional photonic crystal using the transfer matrix method. The photonic crystal structure forms a periodic stack that exhibits photonic suppression regions. By tailoring the layer thicknesses, we have designed a photonic crystal filter that selectively transmits ultraviolet light while efficiently suppressing unwanted wavelengths. Moreover, we demonstrate that a similar effect can be achieved by introducing an interlayer air gap, which, in turn, makes it possible to adjust the system during operation. Through rigorous simulations, the transmission characteristics of the proposed photonic crystal filter have been analyzed. The simulation results demonstrate that the filter exhibits a high degree of ultraviolet light transmission within a specific wavelength range, while effectively suppressing other wavelengths in the visible and near-infrared regions. The ability to selectively transmit ultraviolet light can be utilized in various fields, such as solar energy harvesting, ultraviolet photodetection, and optical sensing. [ABSTRACT FROM AUTHOR]

The presented work focuses on the numerical modeling of the solidification process, with a particular emphasis on two significant physical phenomena: shrinkage cavities and grain formation, which are influenced by the cooling rate. Cooling rate plays a crucial role in determining grain size and casting defects. Higher cooling rates result in finer grain structures, while slower rates promote larger grains. During solidification, atoms arrange into crystalline structures, forming grains. The cooling rate affects grain growth kinetics. Faster rates lead to smaller grains due to limited atomic diffusion, while slower rates allow for larger grain growth. Shrinkage cavities, localized regions in solidified material, form due to volume contraction during cooling, negatively impacting mechanical properties. In this paper, the main assumptions of the mathematical and the numerical model are presented. The numerical description of the problem is based on the finite element method, which is a widely used numerical technique for solving complex physical problems. The algorithm for the shrinkage cavity creation process is described, and an original computer program was developed using the numerical model. The computer simulation was conducted to obtain distributions of temperature, grain size, as well as the position and shapes of the shrinkage cavities. [ABSTRACT FROM AUTHOR]

In the present paper, the phase structure, magnetic properties, and magnetization reversal processes in the (Nd10Fe67B23)93Nb7 alloy ribbon were investigated. The X-ray diffraction analysis revealed a coexistence of the following phases: hard magnetic Nd2Fe14B, metastable soft magnetic Nd2Fe23B3, and paramagnetic Nd1+εFe4B4. Moreover, the changes in phase composition were noticed after heat treatment. In order to check magnetic measurements, the hysteresis loops were collected. The magnetization reversal curves were studied by constructing the reversible part of magnetization dependence on the irreversible part of magnetization. [ABSTRACT FROM AUTHOR]

The magnetization process is based on bringing about a unified arrangement of the magnetic domains. During this process, there are shifts and then the rotations of the domain walls. At a later stage, domains with a direction of magnetization that do not correlate with the applied magnetic field disappear. The turnover depends on the size of the domains. For an amorphous structure, the key factors determining the size of the magnetic domains are the distance between the magnetic atoms and the possible presence of crystalline grains. The paper presents the results of research on the influence of Cu addition on the distances between magnetic atoms and the magnetization process in high magnetic fields. The structure of the alloys was studied using X-ray diffraction. The mean grain size was estimated using the Scherrer method. The magnetic properties were determined on the basis of measurements with a vibrating magnetometer. A numerical analysis of the primary magnetization curves was performed. Despite the significant reorganization of the structure, no changes in the distance between the magnetic atoms were observed, as indicated by slight changes in the Dspf parameter. It was found that a small addition of Cu positively influences the improvement of the magnetic properties, in particular the reduction of the value of the coercive field. [ABSTRACT FROM AUTHOR]

In one-dimensional phononic crystals, as a result of multiple destructive interferences of a mechanical wave, the phononic band gap phenomenon occurs, i.e., the lack of propagation of a wave of a given frequency through the structure due to internal reflections at the layer boundary and destructive interference. In dynamic phononic crystals, the incident monochromatic mechanical wave at the boundary of the media does not propagate according to Fresnel's relations, but is transformed into a wave spectrum, which affects the phononic properties of the examined structures and allows them to be dynamically controlled. The paper analyzes the transmission and influence of the frequency of changes in the properties of the elements of the finite phononic structure described by sinusoidal functions on the propagation of mechanical waves. [ABSTRACT FROM AUTHOR]

Thanks to the use of modern intelligent materials, such as composites consisting of piezoceramic fibers embedded in epoxy resin and covered with alternating electrodes, electroactive polymers, dielectric elastomers, magnetostrictive composites with epoxy resin or ferromagnetic alloys with shape memory, it is possible to control the geometry or properties of materials using pressure, external magnetic or electric fields. The paper analyzes multilayer quasi-one-dimensional phononic structures in which the selected layer is made of a material with time-varying acoustic impedance. The influence of the shape of the material properties changes over time (square wave, triangle wave, sawtooth wave) on the propagation of mechanical waves in the structure is analyzed. [ABSTRACT FROM AUTHOR]

Phononic quasi-two-dimensional structures, due to their properties, namely the lack of propagation of selected frequency ranges of the mechanical wave, can be used as filters of acoustic waves. In the paper, an analysis of the propagation of mechanical waves in these highly dispersive structures in the conditions of a moving medium was carried out. The influence of the number of metaatom layers on the transmission of a mechanical wave for different medium velocities was analysed. [ABSTRACT FROM AUTHOR]

In this paper, an analytical approach to the temperature profile in the normal current leads to the superconducting electromagnets has been proposed. The heat diffusion equation was solved for a one-dimensional case. The static and dynamic temperature distribution in linear leads through which the current flows has been determined. The influence of the thermal intercepts on the current lead temperature distribution during current flow has been investigated, especially the temperature and position of the intercept, and the current lead cross-section. [ABSTRACT FROM AUTHOR]