Ultrasonic Modes Research Articles

Electric Quadrupolar Contributions in the Magnetic Phases of UNi_{4}B.

We present acoustic signatures of the electric quadrupolar degrees of freedom in the honeycomb-layer compound UNi_{4}B. The transverse ultrasonic mode C_{66} shows softening below 30K both in the paramagnetic phase and antiferromagnetic phases down to ∼0.33 K. Furthermore, we traced magnetic field-temperature phase diagrams up to 30T and observed a highly anisotropic elastic response within the honeycomb layer. These observations strongly suggest that Γ_{6}(E_{2g}) electric quadrupolar degrees of freedom in localized 5f^{2} (J=4) states are playing an important role in the magnetic toroidal dipole order and magnetic-field-induced phases of UNi_{4}B, and evidence some of the U ions remain in the paramagnetic state even if the system undergoes magnetic toroidal ordering.

АНАЛИЗ ПРОЦЕССА ИЗМЕНЕНИЯ СВОЙСТВ И СТРУКТУРЫ МАТЕРИАЛА ОБРАЗЦОВ ПОД ВОЗДЕЙСТВИЕМ УЛЬТРАЗВУКОВОЙ СТАБИЛИЗАЦИИ

The most important task of precision engineering on the modern stage is the development of effective technological processes of manufacturing, providing not only achieving high precision at low costs, but also retaining the original in terms of accuracy throughout the life of the product. (Research purpose) The research purpose is in studying the possible negative effect of ultrasonic mechanical vibration in the process of stabilizing the deformation of circular plates on the subject of appearing of various kinds of micro-cracks, which result will be a sharp decrease in resource products in general, and to make a comparative analysis of changes in the properties and structure of the material. (Materials and methods) Half of the prepared samples were processed using a thermomechanical technology based on the cyclic action of a liquid or gas in different temperature conditions, the other part of the samples was processed using the proposed technology based on the method of ultrasonic mechanical action. The end section of the round plate for both processing options was prepared. (Results and discussion) In the structure of the material of both the samples treated by different methods, there are certain bundles of the micro-cracks type caused by plastic impact. The structure of sample material processed by standard method is more rough, the concentration of microcracks in the material of the sample treated by ultrasonic impact does not exceed the concentration of microcracks of the sample material processed in a standard way. (Conclusions) Changing the structure of the material of the round plate after ultrasonic treatment may not have a negative impact and does not affect the durability of the product during operation. With the correct choice of the ultrasonic treatment mode, a more uniform stress reduction can be achieved during the processing, and the quality and efficiency of the process can be improved. Ultrasonic processing increases the mechanical characteristics of the material, such as tensile strength and proportionality.

The fundamental ultrasonic edge wave mode: Propagation characteristics and potential for distant damage detection

Engineering structures are often composed of thin elements containing features such as free edges, welds, ribs, and holes, which makes distant safety inspections based on guided waves difficult due to wave scattering. However, these features can themselves generate so-called ‘feature-guided’ waves, which can potentially be utilised for damage detection. One such example are flexural wedge waves, which have been investigated extensively both theoretically and experimentally in the past. Another example is edge waves. These waves, which are a natural analogue of Rayleigh waves propagating in a finite thickness plate, have received relatively little attention, specifically with respect to their possible use in distant damage inspections and Structural Health Monitoring systems. The current paper is aimed to address this gap, and it is focused on the investigation of the fundamental mode of edge waves (ES0), which is the most promising for practical applications. The features of the transient ES0 mode are investigated experimentally and numerically, and compared with previous theoretical studies. It was demonstrated that the ES0 mode can be effectively excited with the wedge excitation method, and distant damage detection with this wave mode at low frequency-thickness values (FTV < 5) is readily achievable. In particular, in a laboratory environment the ES0 mode propagated several meters with almost no decay. However, at higher frequency-thickness values, a wave amplitude modulation, significant energy decay and strong coupling between the ES0 and S0 wave modes were observed. These phenomena may restrict the defect resolution as well as the range of damage inspections based on the fundamental edge wave mode.

Analysis of Flaw Detection Sensitivity of Phased Array Ultrasonics in Austenitic Steel Welds According to Inspection Conditions.

The anisotropy and inhomogeneity exhibited by austenitic steel in welds poses a challenge to nondestructive testing employing ultrasonic waves, which is predominantly utilized for the inspection of welds in power plants. In this study, we assess the reliability of phased array ultrasonic testing (PAUT) by analyzing the flaw detection sensitivity of ultrasonic beams in anisotropic welds, based on the inspection conditions. First, we simulated the sectorial scan technique, frequently employed for the inspection of actual welds, while taking into account the ultrasonic wave mode, frequency, and shape and position of a flaw. Subsequently, we analyzed the flaw sensitivity by comparing A-scan signals and S-scan results. The sensitivity analysis results confirmed the detection of all flaws by considering at least two inspection methods based on the shape and position of the flaw. Furthermore, we verified our model by performing an experiment under the same conditions as the simulation and found that the results were in agreement. Hence, we find that the simulation modeling technique proposed in this study can be utilized to develop suitable inspection conditions, according to the flaw characteristics or inspection environment.

Modelling and simulation of ultrasonic descaling in heat exchanger

Heat exchanger is widely used in petrochemical industry, long cycle operation will lead to the generation of scaling and the reduction of heat transfer coefficient, but the traditional scale removal method is not convenient to operate with high cost. In this paper, a kind of ultrasonic descaling technology is designed, and the propagation model of ultrasonic wave in heat exchanger is established by using B-P neural network, including the propagation model of ultrasonic load on tube plate and the propagation model of ultrasonic load in medium. Based on the influence of two different ultrasonic loading modes, the propagation mechanism of ultrasonic load on the tube plate of heat exchanger was obtained by simulation research. Finally, the propagation mechanism model of ultrasonic wave in heat exchanger is established successfully through experimental verification.

АНАЛИЗ ПРОЦЕССА ИЗМЕНЕНИЯ СВОЙСТВ И СТРУКТУРЫ МАТЕРИАЛА ОБРАЗЦОВ ПОД ВОЗДЕЙСТВИЕМ УЛЬТРАЗВУКОВОЙ СТАБИЛИЗАЦИИ

The most important task of precision engineering on the modern stage is the development of effective technological processes of manufacturing, providing not only achieving high precision at low costs, but also retaining the original in terms of accuracy throughout the life of the product. (Research purpose) The research purpose is in studying the possible negative effect of ultrasonic mechanical vibration in the process of stabilizing the deformation of circular plates on the subject of appearing of various kinds of micro-cracks, which result will be a sharp decrease in resource products in general, and to make a comparative analysis of changes in the properties and structure of the material. (Materials and methods) Half of the prepared samples were processed using a thermomechanical technology based on the cyclic action of a liquid or gas in different temperature conditions, the other part of the samples was processed using the proposed technology based on the method of ultrasonic mechanical action. The end section of the round plate for both processing options was prepared. (Results and discussion) In the structure of the material of both the samples treated by different methods, there are certain bundles of the micro-cracks type caused by plastic impact. The structure of sample material processed by standard method is more rough, the concentration of microcracks in the material of the sample treated by ultrasonic impact does not exceed the concentration of microcracks of the sample material processed in a standard way. (Conclusions) Changing the structure of the material of the round plate after ultrasonic treatment may not have a negative impact and does not affect the durability of the product during operation. With the correct choice of the ultrasonic treatment mode, a more uniform stress reduction can be achieved during the processing, and the quality and efficiency of the process can be improved. Ultrasonic processing increases the mechanical characteristics of the material, such as tensile strength and proportionality.

Smartphone-Based Automated Non-Destructive Testing Devices

Currently, non-destructive testing is an interdisciplinary field of science and technology that serves to ensure the safe functioning of complex technical systems in the face of multifactorial risks. In this regard, there is a need to consider new information technologies based on intellectual perception, recognition technology, and general network integration. The purpose of this work was to develop an ultrasonic flaw detector, which uses a smartphone to process the test results, as well as transfer them directly to an powerful information processing center, or to a cloud storage to share operational information with specialists from anywhere in the world.The proposed flaw detector consists of a sensor unit and a smartphone. The exchange of information between the sensor and the smartphone takes place using wireless networks that use "bluetooth" technology. To ensure the operation of the smartphone in the ultrasonic flaw detector mode, the smartphone has software installed that runs in the Android operating system and implements the proposed algorithm of the device, and can serve as a repeater for processing data over a considerable distance (up to hundreds and thousands of kilometers) if it necessary.The experimental data comparative analysis of the developed device with the Einstein-II flaw detector from Modsonic (India) and the TS-2028H+ flaw detector from Tru-Test (New Zealand) showed that the proposed device is not inferior to them in terms of such characteristics as the range of measured thicknesses, the relative error in determining the depth defect and the object thickness. When measuring small thicknesses from 5 to 10 mm, the proposed device even surpasses them, providing a relative measurement error of the order of 1 %, while analogues give this error within 2–3 %.

Condition assessment of timber utility poles using ultrasonic guided waves

In this study, guided stress waves were used to evaluate the conditions of a timber utility pole experimentally and numerically using COMSOL Multiphysics. Macro Fiber Composites (MFCs), due to their flexibility and convenience to install on curved surfaces, were used to actuate and sense guided waves along the tested specimens. Based on the wave propagation characteristics in these types of structures, an MFC actuator ring, which was developed in the previous work, was applied to tune and enhance the propagating wave modes. The designed ring was used to excite longitudinal ultrasonic wave modes, mainly L(0,1), to determine the embedded length of the pole and damage localization, in both traction free and embedded conditions.Embedding the timber in the soil had minimum impact on the wave propagation characteristics, given that the waves were confined in the timber pole with minimal leakage to the surrounding. The embedded length was determined accurately for the sound and the damaged timber specimen, using both experimental and numerical data with an error of less than 3%. The deterioration in the timber structure, within the embedded region, was also evaluated with high accuracy of 93%. Based on the obtained results, guided waves have a high potential to be used as a non-destructive tool for the assessment and evaluation of timber utility poles.

Effects of ultrasound modification at different frequency modes on physicochemical, structural, functional, and biological properties of citrus pectin

Ultrasonic irradiation for modified pectin preparation has become a research hotspot, but the influence of ultrasonic frequency is rarely studied. Therefore, in this study, mono frequency (MFU) and simultaneous dual frequency (SDFU) ultrasounds were used to modify citrus pectin (CP), and the effects of different ultrasonic frequency modes on the physicochemical, structural, functional, and biological properties of CP were comparatively investigated. The results showed that ultrasonic irradiation at 40 kHz in the MFU mode led to a larger increment in the galacturonic acid content of CP, but greater reductions in its intrinsic viscosity, molecular weight, and degree of methoxylation than in the SDFU modes. Ultrasonic frequency had no significant influence on the main CP chain, but rather on its neutral sugar side chains. The scanning electron microscopy (SEM) results suggested that CP treated by ultrasound at 40 kHz in the MFU mode exhibited fewer aggregates or looser networks than other ultrasonic treatments. Compared with the original CP, ultrasound treatment at different frequency modes effectively enhanced the thermal stability of CP, but remarkably lowered its shear thinning fluid behavior and liquid-like property. Moreover, among ultrasonically treated CPs, the CP obtained through ultrasound at 40 kHz in MFU mode exhibited the best antioxidant activity and bile acid-binding capacity in vitro.

Theoretical explanation of the ultrasonic action pulsed mode on liquid to reduce cavitation

The article is devoted to theoretical studies of the possibility of reducing cavitation in a medium by using a pulsed exposure mode. A model of the formation and propagation of pulsed ultrasonic vibrations in a liquid is proposed. Pulse shapes are obtained taking into account the distortions arising in the technological volume. On the basis of the identified shapes, the shapes and positions of cavitation zones were calculated, which showed a decrease in the volume of zones in which cavitation bubbles arise under impulse action compared to continuous.

Configuration Optimization of Ultrasonic Descaling Device for Condenser Based on Solidworks-Fluent

As a key component of the open circulation cooling system, the condenser of the power plant is very prone to fouling. After the condenser cooling pipe is scaled, the heat transfer resistance increases, which reduces the heat transfer coefficient and heat exchange efficiency of the heat exchange equipment, which is not conducive to improving the energy efficiency. Therefore, the research on condenser descaling technology has attracted widespread attention. Ultrasonic descaling is a new type of online descaling technology. Its application effect in descaling of condensers in power plants has been verified by actual engineering, but it lacks optimization of the arrangement and configuration of ultrasonic devices. In order to explore the influence of various ultrasonic parameters on the descaling effect, this paper builds a 3D geometric model of the condenser in Solidworks based on the relevant structural parameters of the N-20910 condenser, meshing the model reasonably and setting the boundary conditions. Then, in Fluent, the descaling effect is characterized by the pressure change curve of the specific position of the fluid in the condenser pipe. By setting three different ultrasonic inlet modes and different ultrasonic sound pressure functions, the effects of the quantity, power, frequency and distribution of ultrasonic descaler on the internal flow field and descaling effect of the condenser are compared and analyzed. The simulation results can provide effective help for the optimization and parameter setting of the ultrasonic descaling device of the power plant condenser.

Selective actuation and sensing of antisymmetric ultrasonic waves using shear-deforming piezoelectric transducers

Structural health monitoring of thin plate and beam structures using ultrasonic guided wave techniques has been widely studied and demonstrated advanced capabilities dependent on detailed analysis of specific guided wave modes. A common setup employs the d31 electromechanical coupling of piezoelectric wafer active sensors mounted on the surface of a beam or plate. Analysis of output signals from these basic systems is complicated because they represent multiple superposed ultrasonic wave modes that propagate at different velocities, are dispersive, and undergo reflection, refraction, and mode conversion. Multiple techniques have been pursued to overcome this complication. This article presents recent research into the use of shear-deforming lead zirconate titanate piezoelectric transducers, employing the d15 electromechanical coupling property, embedded within beam-like structures to selectively actuate and sense specific ultrasonic wave modes. The internally located transducers actuated and sensed transverse shear, coupled to bending and antisymmetric waves. A combination of results from finite element simulations and experiments found that d15 transducers located at the neutral axis of a beam exclusively coupled to antisymmetric wave modes and did neither directly actuate nor sense symmetric wave modes. Further study was performed to evaluate the effects of off-neutral-axis location on the mode selectivity and found that off axis location of the d15 transducer did not diminish the coupling to antisymmetric wave modes, but introduced coupling to symmetric wave modes. Additional study was performed to assess the ability of structural health monitoring systems employing shear-deforming d15 lead zirconate titanates located at the neutral axis to detect common forms of damage in laminate structures. The combination of selective actuation and selective sensing provides a powerful tool for signal analysis in ultrasonic structural health monitoring of thin plates and beams.

Adiabatic potential energy surface of the Jahn-Teller complexes in CaF2:Ni2+ crystal determined from experiment on ultrasonic attenuation

In CaF2 crystal doped with Ni2+ ions, attenuation of all the normal ultrasonic modes with the wave vector k||⟨110⟩ were investigated at 14–161 MHz in the temperature region of 5–120 K. The observed peaks of relaxation origin were interpreted as manifestation of the Jahn-Teller effect subject to the T1g⊗(eg+t2g) problem. The experimental data made it possible to estimate the parameters of adiabatic potential energy surface: the Jahn-Teller stabilization energies, the linear and quadratic vibronic coupling constants, location of the saddle points and the global minima defined in the 5-dimensional space of symmetrized (tetragonal and trigonal) coordinates.

PROPERTIES OF CONCRETE CONTAINING BLENDED CEMENT AND LIGHTWEIGHT ARTIFICIAL AGGREGATE

The limitation of natural resources and the increase in industrial waste materials have been being the main concern in many developing countries. Therefore, many studies have been conducted to investigate the feasibility of industrial by-products to be used as artificial aggregate in concrete manufacturing. This study examined the influences of using artificial materials as aggregate replacement of natural aggregate and active pozzolana cement as a binder in concrete. Numbers of tests were performed to investigate the fresh and hardened concrete properties in terms of workability, density, expansion and shrinkage, ultrasonic pulse velocity, flexural strength, compressive strength and mode of failure. The specimens consist of cube and prism were prepared and tested after 3, 7 and 28 days of water curing and air curing. Results of concrete with artificial aggregates recorded lower workability due to the high water absorption, lower density of concrete, lower drying shrinkage due to the reduced free water content and lower pulse velocity in concrete. However, the compressive and flexural strengths were improved by 10% and 38% as of normal concrete, respectively. Therefore, the results obtained from this study indicated that the artificial aggregates and pozzolan cement used have positive effects on concrete properties.

PROPERTIES OF CONCRETE CONTAINING BLENDED CEMENT AND LIGHTWEIGHT ARTIFICIAL AGGREGATE

The limitation of natural resources and the increase in industrial waste materials have been being the main concern in many developing countries. Therefore, many studies have been conducted to investigate the feasibility of industrial by-products to be used as artificial aggregate in concrete manufacturing. This study examined the influences of using artificial materials as aggregate replacement of natural aggregate and active pozzolana cement as a binder in concrete. Numbers of tests were performed to investigate the fresh and hardened concrete properties in terms of workability, density, expansion and shrinkage, ultrasonic pulse velocity, flexural strength, compressive strength and mode of failure. The specimens consist of cube and prism were prepared and tested after 3, 7 and 28 days of water curing and air curing. Results of concrete with artificial aggregates recorded lower workability due to the high water absorption, lower density of concrete, lower drying shrinkage due to the reduced free water content and lower pulse velocity in concrete. However, the compressive and flexural strengths were improved by 10% and 38% as of normal concrete, respectively. Therefore, the results obtained from this study indicated that the artificial aggregates and pozzolan cement used have positive effects on concrete properties.

Lysinoalanine formation and conformational characteristics of rice dreg protein isolates by multi-frequency countercurrent S-type sonochemical action

The influences of multi-frequency countercurrent S-type ultrasound (MFSU), with various frequency modes, on lysinoalanine (LAL) formation and conformational characteristics of rice dreg protein isolates (RDPI) were investigated. The ultrasonic operating mode with dual-frequency combination (20/40 kHz) indicated lower LAL content and higher protein dissolution rate of RDPI compared with that of other ultrasound operating modes. Under the dual-frequency ultrasound mode of 20/40 kHz, acoustic power density of 60 W/L, time of 20 min, and temperature of 35 °C, the relative reduction rate of LAL of RDPI reached the highest with its value of 26.95%, and the protein dissolution rate was 71.87%. The changes in chemical interactions between protein molecules indicated that hydrophobic interactions and disulfide bonds played a considerable role in the formation of LAL of RDPI, especially the reduction of g-g-g and g-g-t disulfide bond. Alterations in microstructure showed that ultrasonication loosened the protein structure and created more uniform protein fragments of RDPI. In conclusion, using MFSU in treating RDPI was an efficacious avenue for minimizing LAL content and modifying the conformational characteristics of RDPI.

Synthesis of novel Cubane [Ni4(O∩O)4(OCH3)4(OOH)4] cluster: XRD/HSA-interactions, spectral, DNA-binding, docking and subsequent thermolysis to NiO nanocrystals

Under liquid-state vibration ultrasonic mode, the Ni4(O∩O)4(OCH3)4(OOH)4 complex [O∩O-bidentate ligand = 4,4,4-trifluoro-1-phenylbutane-1,3-dione] was synthesized from metal precursor and ligand in 10% H2O2/MeOH media, as a novel [Ni4(μ3-O)4] cubane cluster. The XRD-structure of the desired cluster was unraveled that each Ni(II) metal center possesses a distorted octahedral geometry. Monitored thermal treatment to the tetranuclear metal cluster in an open atmosphere afforded nanocrystalline rod-shaped nickel oxide. Moreover, CHN-EA, FT-IR, conductivity measurement, UV–Vis., EDX, SEM, TG/DTA, and PXRD have confirmed the structure of the new cluster and NiO nanocrystals. The XRD-lattice interactions were explored to evaluate their role via computational Hirshfeld surface analysis. The molecular docking of the cluster with SS-DNA was estimated and demonstrated.

Modification of rapeseed protein by ultrasound-assisted pH shift treatment: Ultrasonic mode and frequency screening, changes in protein solubility and structural characteristics

We investigated the effect of ultrasound-assisted pH shift treatment on the micro-particle, molecular, and spatial structure of rapeseed protein isolates (RPI). Various ultrasonic frequency modes (fixed, and sweep) was used. Protein characterization by the indexes: particle size, zeta potential, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy (SEM), free sulfhydryl (SH), surface hydrophobicity (Ho), Fourier transform infrared Spectrum (FTIR) and fluorescence intensity was studied to elucidate the changes in solubility and structural attributes of RPI. The results showed that ultrasonic frequency and working modes substantially altered the structure, and modified the solubility of RPI. Ultra + pH mode at fixed frequency of 20 kHz had the best effect on the solubility of RPI. Under the condition of ultra + pH mode, 20 kHz at pH 12.5, solubility, compared to control, increased from 8.90% to 66.84%; and the change in molecular structure of RPI was characterized by smaller particles (from 330.90 to 115.77 nm), high zeta potential (from −17.95 to −14.43 mV, p < 0.05), and increased free sulfhydryl (from 11.63 to 24.50 µmol/g) compared to control. Likewise, surface hydrophobicity increased (from 2053.9 to 2649.4, p < 0.05), whilst ɑ-helix and random coil decreased (p < 0.05), compared to control. The fluorescence spectroscopy and FTIR spectroscopy showed that the secondary and tertiary structure of the RPI were altered. These observations revealed that changes in RPI structure was the direct factor affecting solubility. In conclusion, ultrasound assisted pH shift treatment was proven to be an effective method for the modification of protein, with promising application in food industry.

Ultrasound Measurement of Skeletal Muscle Contractile Parameters Using Flexible and Wearable Single-Element Ultrasonic Sensor.

Skeletal muscle is considered as a near-constant volume system, and the contractions of the muscle are related to the changes in tissue thickness. Assessment of the skeletal muscle contractile parameters such as maximum contraction thickness (), contraction time (), contraction velocity (), sustain time (), and half-relaxation () provides valuable information for various medical applications. This paper presents a single-element wearable ultrasonic sensor (WUS) and a method to measure the skeletal muscle contractile parameters in A-mode ultrasonic data acquisition. The developed WUS was made of double-layer polyvinylidene fluoride (PVDF) piezoelectric polymer films with a simple and low-cost fabrication process. A flexible, lightweight, thin, and small size WUS would provide a secure attachment to the skin surface without affecting the muscle contraction dynamics of interest. The developed WUS was employed to monitor the contractions of gastrocnemius (GC) muscle of a human subject. The GC muscle contractions were evoked by the electrical muscle stimulation (EMS) at varying EMS frequencies from 2 Hz up to 30 Hz. The tissue thickness changes due to the muscle contractions were measured by utilizing a time-of-flight method in the ultrasonic through-transmission mode. The developed WUS demonstrated the capability to monitor the tissue thickness changes during the unfused and fused tetanic contractions. The tetanic progression level was quantitatively assessed using the parameter of the fusion index (FI) obtained. In addition, the contractile parameters (, , , , and ) were successfully extracted from the measured tissue thickness changes. In addition, the unfused and fused tetanus frequencies were estimated from the obtained FI-EMS frequency curve. The WUS and ultrasonic method proposed in this study could be a valuable tool for inexpensive, non-invasive, and continuous monitoring of the skeletal muscle contractile properties.

Characterization of edible soldier fly protein and hydrolysate altered by multiple-frequency ultrasound: Structural, physical, and functional attributes

The effect of conventional (control), and different ultrasonic treatment modes (fixed, and sweep frequency ultrasound) on structural, physical and functional traits of soldier fly (Hermetia illucens) larvae protein preparations and hydrolysates were examined. Ultrasonication significantly increased lightness (L*) of protein isolates by x¯ 7.46 % compared to control. Sonic-treated (particularly sweep-type) isolates and hydrolysates showed significant increases in thiol value, reconstitutability function (pH 2–10), and surface charge; and significant decreases in turbidity, and particle size, relative to controls. Protein isolates were characterized by higher molecular weight (MW) using SDS-PAGE, whereas hydrolysates were lower (with no observable variances). By numerical estimation, hydrolysates (especially the sweep-treated) showed significantly lower MW (<1000 Da). Deconvoluted FTIR spectra (α-helix, β–sheet/turn, random coil fractions), and UV spectra analyses showed differences in samples. Treatment type (sweep/ fixed frequency ultrasound) could be used to alter protein structure, modify functionality, and thereby usage of H. illucens protein/hydrolysate preparations.