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The aim of this work is to develop an experimental method suitable for the mechanical testing of highly non-standard biological samples such as snake skin with osteoderms. The objective of the method is to determine, whether the osteoderms provide a protective function for the animal in its natural environment. For this purpose, a simulation of rodents biting the skin based on uni-axial compressive loading using a synthetic tooth as a penetrator was developed with an emphasis on integration with X-ray scanners to facilitate in-situ testing. To identify and characterise the structure of snake skin and to prove the protective function of osteoderms, all samples were subjected to high resolution X-ray computed tomography. The results of the experiments are presented in the form of stress-strain curves and a map of the tangent modulus.

Mg-Y-Zn-Al alloys processed by rapidly solidified ribbon consolidation (RSRC) technique exhibit an exceptional mechanical performance indicating promising application potential. This material has a bimodal microstructure consisting of fine recrystallized and coarse non-recrystallized grains with solute-rich stacking faults forming cluster arranged layers (CALs) and nanoplates (CANaPs), or complete long period stacking ordered (LPSO) phase. In order to reveal the deformation mechanisms, in-situ synchrotron X-ray diffraction line profile analysis was employed for a detailed study of the dislocation arrangement created during tension in Mg - 0.9% Zn - 2.05% Y - 0.15% Al (at%) alloy. For uncovering the effect of the initial microstructure on the mechanical performance, additional samples were obtained by annealing of the as-consolidated specimen at 300 and 400 °C for 2 h. The heat treatment at 300 °C had no significant effect on the initial microstructure, its evolution during tension and, thus, the overall deformation behavior under tensile loading. On the other hand, annealing at 400 °C resulted in a significant increase of the recrystallized grains fraction and a decrease of the dislocation density, leading to only minor degradation of the mechanical strength. The maximum dislocation density at the failure of the samples corresponding to the plastic strain of 10–25% was estimated to be about 16–20 × 1014 m−2. The diffraction profile analysis indicated that most dislocations formed during tension were of non-basal 〈a〉 and pyramidal 〈c + a〉 types, what was also in agreement with the Schmid factor values revealed independently from orientation maps. It was also shown that the dislocation-induced Taylor hardening was much lower below the plastic strain of 3% than above this value, which was explained by a model of the interaction between prismatic dislocations and CANaPs/LPSO plates.

The next generation architectures of computer networks and systems and commercial technologies such as Big Data, Decentralized Storage, and 6G require novel approaches to prevent cybersecurity breaches which can negatively affect organizations, operations, and individual customers and stakeholders. In this proposal, we present an approach for identifying transformed features via statistical analysis which can be used in Artificial Intelligence (AI) and machine learning (ML) based systems. We also present a deep learning framework, Small Set of Linearized Variables (SSOLV), for training neural networks based on labeled Zeek datasets containing both malicious and benign activity in real or near-real time. In addition, we present a mechanism for transfer learning using domain adaptation techniques to adapt neural networks trained on one labeled Zeek dataset to another neural network trained on a different labeled Zeek dataset. This research uses a combination of 3 techniques commonly used in network traffic flow analysis: deep neural networks, linear regression, and ANOVA. Our results show that we can classify malicious activity with up to 97-99% accuracy in select cases and high precision (>95%) and recall (>90%) rate. This framework demonstrates a mechanism that stand-alone systems disconnected from larger networks can use to recognize adversarial activity in real time and is transferrable to other stand-alone systems. This work is patent pending under U.S. Patent App. Ser. No. 18/121,716 “Linearized Real-Time Network Intrusion Detection System” and U.S. Patent App. Ser. No. 17/900,982 “Real-Time Network Intrusion Detection System.”

Mg-Y-Zn-Al alloys processed by the rapidly solidified ribbon consolidation (RSRC) technique are candidate materials for structural applications due to their improved mechanical performance. Their outstanding mechanical strength is attributed to solute-enriched stacking faults (SESFs), which can form cluster-arranged layers (CALs) and cluster-arranged nanoplates (CANaPs) or complete the long-period stacking ordered (LPSO) phase. The thermal stability of these solute arrangements strongly influences mechanical performance at elevated temperatures. In this study, an RSRC-processed Mg—0.9%, Zn—2.05%, Y—0.15% Al (at%) alloy was heated at a rate of 0.666 K/s up to 833 K, a temperature very close to melting point. During annealing, in situ X-ray diffraction (XRD) measurements were performed using synchrotron radiation in order to monitor changes in the structure. These in situ XRD experiments were completed with ex situ electron microscopy investigations before and after annealing. At 753 K and above, the ratio of the matrix lattice constants, c/a, decreased considerably, which was restored during cooling. This decrease in c/a could be attributed to partial melting in the volumes with high solute contents, causing a change in the chemical composition of the remaining solid material. In addition, the XRD intensity of the secondary phase increased at the beginning of cooling and then remained unchanged, which was attributed to a long-range ordering of the solute-enriched phase. Both the matrix grains and the solute-enriched particles were coarsened during the heat treatment, as revealed by electron microscopy.

Study of musical-acoustic influences, which are used to improve the functional state of a person, as well as her/his neurophysiological or psychological rehabilitation, is very relevant nowadays. It is related with a large number of conflict situations, significant psychological and informational overloads of modern human, permanent stress due to the pandemic, economic crisis, natural and man-made disasters. This work examines the effect of listening to low-frequency music on the percentage of alpha, beta, delta, and theta waves in the total spectral power of the electroencephalogram in the frequency band 0.5–30 Hz. To obtain rhythms of the brain the spectral analysis of filtered native electroencephalogram was used. For statistical analysis of neural oscillations the Student’s t-test and the sign test were implemented with usage of the Lilliefors normality criterion and the Shapiro-Wilk test. Statistically significant differences were identified in alpha, theta and delta oscillations. For the beta rhythm presented music did not play any significant role. An increase in the activity of the alpha rhythm in the temporal (for 2.20 percentage point), central (for 1.51 percentage point), parietal (for 2.70 percentage point), occipital (for 2.22 percentage point) leads of the right hemisphere and the parietal (for 1.74 percentage point) and occipital (for 2.46 percentage point) leads of the left hemisphere and also of the theta rhythm in the temporal leads of the left hemisphere (for 1.13 percentage point) were observed. The downfall of delta rhythm in the frontal lead of the left hemisphere (for 1.51 percentage point) and occipital in both hemispheres (for 1.64 and 1.33 percentage points respectively in the left and right hemispheres) was detected. These may indicate that listening to low-frequency compositions helps to restore the brain in physiological conditions at different functional overload levels, decrease the level of emotional tone, and promote relaxation.

Present work focuses on analysis of the stress and strain fields inside and around the individual {10–12} twin in magnesium alloy. The 3D crystal plasticity model represents twin as an ellipsoidal inclusion surrounded by the matrix. Five different twin thicknesses and three different lateral twin lengths are used for stress/strain analysis. The simulations are complemented with experimental observations using high-resolution electron backscattered diffraction. The simulations and experiments show a similar distribution of the shear stress and the spatial activity of individual slip systems (basal, prismatic, pyramidal). Plasticity induced inside the twin is dominantly caused by the prismatic dislocations slip and does not influence twin back stress which is identical to pure elastic twin. The twin with larger lateral dimension requires lower equilibrium stress which suggests anisotropic twin propagation and increased thickness of such twins. The lateral twin propagation is mostly influenced by prismatic and pyramidal slip in the twin vicinity. The twin thickness can reach a maximal level that is driven by the critical resolved shear stress values for dislocation slip with the significant influence of basal slip.

Mg-Y-Zn-Al alloys processed by the rapidly solidified ribbon consolidation (RSRC) technique are candidate materials for structural applications due to their improved mechanical performance. Their outstanding mechanical strength is attributed to solute-enriched stacking faults (SESFs), which can form cluster-arranged layers (CALs) and cluster-arranged nanoplates (CANaPs) or complete the long-period stacking ordered (LPSO) phase. The thermal stability of these solute arrangements strongly influences mechanical performance at elevated temperatures. In this study, an RSRC-processed Mg—0.9%, Zn—2.05%, Y—0.15% Al (at%) alloy was heated at a rate of 0.666 K/s up to 833 K, a temperature very close to melting point. During annealing, in situ X-ray diffraction (XRD) measurements were performed using synchrotron radiation in order to monitor changes in the structure. These in situ XRD experiments were completed with ex situ electron microscopy investigations before and after annealing. At 753 K and above, the ratio of the matrix lattice constants, c/a, decreased considerably, which was restored during cooling. This decrease in c/a could be attributed to partial melting in the volumes with high solute contents, causing a change in the chemical composition of the remaining solid material. In addition, the XRD intensity of the secondary phase increased at the beginning of cooling and then remained unchanged, which was attributed to a long-range ordering of the solute-enriched phase. Both the matrix grains and the solute-enriched particles were coarsened during the heat treatment, as revealed by electron microscopy. [ABSTRACT FROM AUTHOR]

Copper (Cu) foams with high porosity of about 63–78% were processed by the freeze-casting (FC) and space-holder (SH) methods. The FC and SH techniques yielded lamellar and polygonal pore structures, respectively, with similar porosities. The deformation behaviors of the two different types of Cu foams were compared using uniaxial compression and a simultaneous acoustic emission (AE) and video recording analysis. It was found that the compressive yield strength values for the FC-Cu and SH-Cu foams were significantly different, which were 19–29 MPa and 1.2–2.3 MPa, respectively. Furthermore, the energy absorbed during compression up to the strain of 50% was obtained as ∼12.3 MJ m−3 and ∼2.7 MJ m−3 for the FC-Cu and SH-Cu foams, respectively, resulting in approximately 4.6 times higher energy absorption capability for the FC-Cu foam. The deformation processes occurring during compression in the two Cu foams were studied by the AE and image analysis. The video and the evaluated AE parameters (e.g., the AE voltage, the cumulative number of events, and the cumulative energy) revealed that, in the case of the FC foam, the localized fracture of the struts within a well-defined single deformation band took place, which gave rise to pronounced AE signals (mostly in the plateau stage of compression). By contrast, the deformation was highly homogeneous in the case of the SH-Cu foam, and the main deformation mechanisms were gradual bending and buckling of the foam struts during compression.

The relevance. Explosive mining requires destroying rocks that lie at different depths in different mining and geological conditions and have different physical and technical properties. Explosion of explosive blast charges generates stress waves and pressure of explosion products, which have different effects on rocks of different hardness and to improve their action, explosive blast charges must be blasted with different deceleration. The main aim of the research is to take into account the energy characteristics of explosives, the position of borehole charges relative to the natural fracturing of the rock to improve the quality of fracture of blasted rock. Objects: underground construction facilities, coal and ore mines, mining enterprises for open-pit and underground mining. Methods. To achieve this goal, we used field studies to establish the dependence of rock fracture quality on the operating time of bore charges, as well as analytical studies that allowed us to determine the values of the limiting radii of expansion of the charge cavity for some types of explosives. Results. The results of the research are a more complete accounting of energy characteristics of explosives, the optimal volumetric position of borehole charges in relation to systems of natural fracturing of the environment, their correlation with the hardness of rocks, the cross section of mine workings and the depth of placing explosives charges, leading to creation of rational volumes of cuts, providing the highest performance blasting operations.

Goal. Analysis of the effect of load inductance at the output of the class D amplifier for different values of the duration of «dead time» and assessment of the adequacy of existing mathematical models for calculating the THD at the output of the amplifier depending on the duration of «dead time». Methodology. The study of the effect of «dead time» on the THD was performed using a computer model of the half-bridge converter board EPC9035 from Efficient Power Conversion. This board contains GaN transistors EPC2022 eGaN®, the corresponding control driver and other necessary elements for operation. The use of GaN transistors has made it possible to investigate the operation in a wide range of frequent switching, both to control the motor and to amplify the audio signal. Results. It is established that the value of load inductance affects the level of nonlinear distortions caused by «dead time». At inductance values that provide a constant sign of the output current, a difference arises between the duration of the input and output pulses, which increases the THD. At inductance values, when the choke current changes sign during a pulse, there is no error between the duration of the input and output pulses. Changing the inductance changes the relationship between the error signal and the non-error signal. THD changes accordingly. At high conversion frequencies, the voltage spikes caused by the choke current through the built-in diodes during the dead time are partially compensated by overcharging the output capacitance of the transistors, which also reduces harmonic distortion. Originality. For the first time, the value of the THD at the outlets in the fallowness of the different indices of the inductance of the choke and the theoretical calculation of the value in the results of the computer model was obtained. Practical significance. The dependence of the THD values on the inductance of the choke for converters with a switching frequency range from 1 kHz to 400 kHz, which allows them to be used both to control the motor and to amplify the audio signal.

In this work, the possibility of application the device with a non-standard (side) piezoelectric sensor installation for rail condition monitoring is considered. The aim of this device application is reducing the risks of using single-strand flaw detectors on railway tracks with fixation system on the rail in the form of two rebords. Also, the application of this device allows you to obtain a new qualification criterion for the integrity of the rail, which is located in the railroad groundwork. This criterion is the presence of a signal from the opposite face of the rail head, which, in addition to the possible detection of a 30В.1-2 defect (DG) or 113 also allows you to record developed defects of the rail neck, passing into its head and implemented by sounding the rail head of the linear section of the track in the transverse direction (from the working to the non-working face). The study of round ultrasonic transducers of different frequencies was carried out. It has shown impossibility of using 10 MHz transducers. The results of statistical estimation of rail thickness and corresponding amplification levels are presented. The presence of statistically significant differences in the monitoring of different frequencies sensors and different sensors of the same frequency (which is relevant only for 5 MHz) was found. The difference between the maximum and minimum average in the test group of measured values of rail thickness was 0.06 mm, and between amplification levels — 17 dB.

The deformation behavior of the Mg-Al-Mn sheet was investigated during tensile loading along the rolling (RD) and transversal direction (TD) with special attention to the early stage of deformation. The activity of dislocation slip systems during the transition from elastic to plastic deformation was revealed by the acoustic emission (AE) technique. The parametrization and statistical AE analysis using the adaptive sequential k-mean (ASK) clustering provided necessary information about the individual deformation mechanisms and their evolution. The AE findings were supported by microstructural analyses, including in-situ secondary electron (SE) imaging and Schmid factor estimation for the activity of particular dislocation slip systems with respect to the loading direction. It was found that basal slip is the dominating mechanism up to the stress of ∼ 80 MPa in both loading directions with an absolute dominance during the RD-loading, while during the TD-loading, the contribution of prismatic slip to the deformation at stresses above 50 MPa was determined. Below the yielding in both loading directions, the predominance of prismatic over pyramidal slip was found at the stress in the range of 80–110 MPa and the opposite tendency occurred at stresses between 110 and 140 MPa.

A review of modern methods of forming a mathematical model of power systems and the development of an intelligent information system for monitoring electricity consumption. The main disadvantages and advantages of the existing modeling approaches , as well as their applicability to the energy systems of Ukraine and Kazakhstan,are identified. The main factors that affect the dynamics of energy consumption are identified. A list of the main tasks that need to be implemented in order to develop algorithms for predicting electricity demand for various objects, industries and levels has been developed.

The compressive deformation behavior of the extruded WZ42 (Mg98.5Y1Zn0.5 in at.%) magnesium alloy containing a low amount of long-period stacking ordered (LPSO) phase was studied by in-situ synchrotron radiation diffraction technique. Tests were conducted at temperatures between room temperature and 350 °C. Detailed microstructure investigation was provided by scanning electron microscopy, particularly the backscattered electron imaging and electron backscatter diffraction technique. The results show that twinning lost its dominance and kinking of the LPSO phase became more pronounced with increasing deformation temperature. No cracks of the LPSO phase and no debonding r at the interface between the LPSO phase and the Mg matrix were observed at temperatures above 200 °C. At 350 °C, the LPSO phase lost its strengthening effect and the deformation of the alloy was mainly realized by the dynamic recrystallization of the Mg matrix. Keywords: Magnesium alloy, LPSO phase, Kinking, High temperature, Synchrotron radiation diffraction

This paper presents the research of dielectric properties of (FeCoZr)x(Pb(ZrTi)O3)(100−x) granular metal–dielectric nanocomposites below the percolation threshold. Tested materials have been prepared by using the ion beam sputtering technique in the atmosphere of argon and oxygen. The impedance spectroscopy method has been used to investigate the polarization processes and dielectric relaxation mechanism in the granular nanocomposites. AC measurements in the frequency region of 50 Hz to 1 MHz and measuring temperature range of 81–293 K have been performed. Interfacial, in the low frequency region, and dipolar, in intermediate and high frequency regions, types of polarization processes were observed. The interfacial relaxation process testifies to charge accumulation at the interfaces (grain boundaries) between conductive nanoparticles surrounding an insulative matrix, as well as the space charge region around the contact area between the measurement probes and tested sample. Dipolar polarization corresponds to electric dipole formation after applying to the material an external electric field. The conduction mechanism in the tested material is considered to be hopping carrier exchange and takes place between metallic phase nanograins. It corresponds to the exponential frequency dependence of conductivity. The relaxation mechanism in the (FeCoZr)x(Pb(ZrTi)O3)(100−x) layer has been estimated as a near-Debye process with relaxation time distribution. The nanocomposite exhibits dielectric type and capacitive characteristics in the whole measuring frequency range.