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Infrastructure and urbanization drive the increasing demand for concrete, which strains natural resources and threatens the ecosystem. Incorporating recycled materials into concrete can fulfill this demand without compromising quality. This study therefore examines the mechanical properties of concrete after replacing sand utilizing fine aggregates of brick powder (BP) using appropriate standard techniques of destructive and nondestructive testing methods. Concrete mixtures were developed by incrementally substituting sand with brick powder in ratios from 5% to 25% and evaluated for workability, compressive strength, and split tensile strength in comparison to conventional concrete. The findings indicate that replacing 10% sand with brick powder improves strength by 29.94%, reduces workability by 42.66%, and increases split tensile strength by 8.74%. A strong link was found between compressive strength, ultrasonic pulse velocity (UPV), and rebound number, which was confirmed by regression analysis. Integrating 10% brick powder improves concrete's mechanical properties and promotes sustainable construction practices. [ABSTRACT FROM AUTHOR]

Microwave-absorbing suspicious objects (MASOs) found using microwave-induced thermoacoustic imaging (MTI) can be divided into two types—endogenous (such as tumors or hematoceles) and exogenous (such as calculi or foreign bodies). These have different microwave absorption or ultrasonic velocity than normal human tissue, so MTI is efficient in detecting these anomalies. However, the existing MTI techniques can only reflect morphological information, making it difficult to distinguish the type of each anomaly. In this paper, a newly enhanced MTI system composed of a multiple-element ring transducer and a parallel data acquisition system (DAS) is presented. By using ultrasonic velocity and microwave absorption measurements, where the ultrasonic velocity is mainly used as an additional parameter to reflect mechanical characteristics, the type of the detected anomaly can be identified. In our experiments, the MASO can be located through the absorption difference detected by MTI. Due to the use of multiple-element transducers and a parallel DAS, the raw data can be acquired within about 20 ms for a two-dimensional image. Additionally, the ultrasonic velocity of the MASO can be calculated from the time sequence diagram of ultrasound propagation with a maximum time error of 0.084 μs. Apart from distinguishing the type of the anomaly, the proposed ultrasonic velocity-assisted microwave-induced thermoacoustic imaging (US-MTI) system has other advantages, such as being noninvasive, and allowing rapid imaging and a large field of view, which make US-MTI a suitable modality for regular screening. [ABSTRACT FROM AUTHOR]

Given the growing importance of organic-rich shale as unconventional reservoirs, a thorough understanding of the elastic and anisotropic behavior of shales is of great concern. However, for lacustrine shales, the complex lithofacies assemblage with geological deposition makes it challenging. Four lithofacies (argillaceous, mixed, siliceous, and calcareous) are recognized for 40 lacustrine shale samples from Jurassic formation in Sichuan Basin on the basis of their mineral compositions. We perform ultrasonic velocity measurements on 40 pairs of shale plugs at varied confining pressures, attempting to uncover the controls on the anisotropic properties of different lithofacies. The experimental results reveal that the total porosity, clay, and organic matter would positively contribute to velocity anisotropy of Jurassic shales. Combined with microstructure and pressure-dependent velocity analysis, the preferred orientations of platy clay particles and lenticular kerogen, the development of clay pores along clay fabric, and the sub-parallel micro-cracks induced by hydrocarbon expulsion are treated to be the controlling mechanisms. We add the total porosity, clay content, and kerogen volume together, intending to distinguish the elastic and anisotropic properties of four lithofacies. Generally, argillaceous shales, the dominant lithofacies in Jurassic formation, could be characterized by the highest clay and total organic content (TOC), the lowest bedding-normal velocities, and the strongest velocity anisotropy. Finally, with the laboratory data, two rock-physics-driven exponential relationships are proposed to predict the P- and S-wave velocity anisotropy with the bedding-normal velocities. [ABSTRACT FROM AUTHOR]

A suspended dense graded broken stone road foundation stabilized by cement is a commonly employed material in roadworks, which is vulnerable to harm caused by freezing and thawing processes. This investigation intends to evaluate the laboratory behavior and the characteristics of freezing and thawing process-induced deterioration in a broken stone road foundation stabilized by cement with suspended dense grading, employing mechanical examinations and acoustical methods. The rate of mass loss in the broken stone road foundation stabilized by cement progressively rises, and the rate of decline in the compressive strength could potentially intensify as freezing and thawing processes augment. The modulus of resilience diminishes as freezing and thawing processes progress, and ultrasonic wave velocity also decreases. The patterns of mass loss, compressive strength decline, resilience modulus reduction, and ultrasonic wave velocity alteration adhere to a parabolic fitting relationship with freeze–thaw cycles, with an R2 above 0.95. The curves depicting the relationship of mass, compressive strength, resilience modulus, and ultrasonic wave velocity exhibit a steeper trend significantly after 10–15 cycles, which can be ascribed to the emergence of microcracks and the progression of flaws within the material. The evolution of damage in the broken stone road foundation stabilized by cement is monitored to progress through three distinct stages based on acoustic emission: initial, stationary, and failure. As freezing and thawing processes accumulate to 20 cycles, the length of initial phase correspondingly rises to three times, the length of failure stage diminishes to about one fifth. [ABSTRACT FROM AUTHOR]

Infrastructure and urbanization drive the increasing demand for concrete, which strains natural resources and threatens the ecosystem. Incorporating recycled materials into concrete can fulfill this demand without compromising quality. This study therefore examines the mechanical properties of concrete after replacing sand utilizing fine aggregates of brick powder (BP) using appropriate standard techniques of destructive and non-destructive testing methods. Concrete mixtures were developed by incrementally substituting sand with brick powder in ratios from 5% to 25% and evaluated for workability, compressive strength, and split tensile strength in comparison to conventional concrete. The findings indicate that replacing 10% sand with brick powder improves strength by 29.94%, reduces workability by 42.66%, and increases split tensile strength by 8.74%. A strong link was found between compressive strength, ultrasonic pulse velocity (UPV), and rebound number, which was confirmed by regression analysis. Integrating 10% brick powder improves concrete's mechanical properties and promotes sustainable construction practices.

Ammonium bromide, a water-soluble wood preservative used in pharmaceutical preparations, is the focus of this economic study aimed at understanding its physical properties in aqueous solutions. A straightforward and reliable method for examining interactions between molecules in liquids and solutions is ultrasonic research. When ultrasonic waves pass through liquids, they disturb the equilibrium between the molecules of the solute and solvent. Ion-ion and ion-solvent interactions are just two aspects of solvation chemistry that ultrasonic velocity measurement can elucidate. This study investigates the hydration number of aqueous solutions of ammonium bromide at temperatures ranging from 35 to 55°C, assessing both density and ultrasonic velocity across various concentrations. From the adiabatic compressibility, the hydration number and related parameters are derived, all of which are sensitive to changes in concentration and temperature. Thus, we explore how these parameters vary with changes in temperature and concentration, providing insight into the interactions of ions and molecules in the solutions, as well as their molecular structure.

The skeleton dense graded cement-stabilized crushed stone base is a widely used material for road construction. However, this material is susceptible to freeze–thaw damage, which can lead to degradation and failure, for which there is still a lack of an in-depth understanding of the freeze–thaw damage characteristics. This study aims to assess the mechanical performance and the freeze–thaw damage characteristics of the cement-stabilized crushed stone base with skeleton dense gradation based on a mechanical test and acoustic technology in a laboratory. There is a gradually increasing trend in the mass loss rate of the base material with an increase in freeze–thaw cycles. The curve steepens significantly after 15 cycles, following a parabola-fitting pattern relationship. The compressive strength of the cement-stabilized crushed stone base also decreased with a parabola-fitting pattern, and the decrease rate may accelerate as the freeze–thaw cycles increase. The resilience modulus of the base material decreased with increasing freeze–thaw cycles, following a parabolic trend. This suggests that the material's resistance to freeze–thaw damage decreases with increasing cycles. The ultrasonic wave velocity decreased with increasing freeze–thaw cycles, exhibiting a parabolic trend. This decline can be attributed to microcracks and defects developing within the material, offering insights for monitoring and predicting its service life. The damage progression of the cement-stabilized crushed stone base was found to occur in three stages: initial, stationary, and failure. The duration of stage I increased with freeze–thaw cycles, while the duration of stage III decreased. The findings provide valuable insights into the mechanisms and processes of freeze–thaw damage in a cement-stabilized crushed stone base with skeleton dense gradation. [ABSTRACT FROM AUTHOR]

Sulfate attack seriously affects the durability of concrete structures, and many tunnels constructed in China in the early years did not adequately take it into account, resulting in structural degradation of many currently operating tunnels within their service life. In this study, we integrated experimental and machine learning (ML) approaches to assess tunnel concrete. Specifically, we compared concrete deteriorated by sulfate attack with freshly poured lining concrete that was built using the same mix ratio. By analyzing ultrasonic velocity data for different periods in wet and dry cyclic accelerated erosion experiments, we evaluated the effectiveness of multiple time series statistical methods, ML techniques, and their optimization algorithms. Through the analysis, we derived the best prediction model Particle Swarm Optimization - Long Short Term Memory (PSO-LSTM) and its Markov-corrected prediction results. Based on the damage time nodes of concrete compressive strength corrosion resistance coefficient (CCSCRC) and its actual damage in the test, the damage nodes of the target lining concrete of the existing tunnel are predicted. The experimental results show that: (1) The PSO-LSTM model is well adapted to the prediction of the deterioration data for concrete subjected to sulfate attack, with a model correlation coefficient R2 of 0.9739. (2) The PSO-LSTM model corrected by Markov chain can effectively capture the trend of the predicted data of concrete subjected to sulfate attack and improve the prediction accuracy. (3) When the CCSCRC decreased to 82 %, the loosening and granulation of the tunnel concrete occurred. In addition, actual failure of the concrete structure was observed at 677.6 days after sampling, less than two years. The outcomes of this research enhance the precision in predicting the service life of tunnel linings subjected to sulfate attack, providing valuable insights for on-site maintenance and construction, and contributing as a reference for similar studies.

The non-destructive characterization of ultrasonic properties in mixtures of vegetable oils with similar dominant chemical compositions is becoming increasingly important for various applications. The combination of ultrasonic wave reflection as an experimental method and the partial least squares statistical method has been employed to establish reference graphs and models for detecting adulterated oils. This experimental study focuses precisely on measuring the attenuation and ultrasonic velocity of mixtures of organic argan oil with volumetric fractions of sesame oil, peanut oil or argan oil extracted from kernels depulped by goats. The measurements exhibit distinct behaviors manifested by electrical signals for the mixture obtained after the addition of each volumetric fraction, reflecting the capability of the adopted method to detect this difference. A notable decrease in ultrasonic velocity is observed in the mixtures as the quantity of added oil increases, with a maximum variation of 11 m/s for the argan/peanut oil mixture. Conversely, The attenuation of ultrasonic waves increases proportionally with the added volumetric fractions, with the argan/peanut oil mixture exhibiting an attenuation variation range of 3.57 Np/m. Prediction models for the added volumetric fractions to organic argan oil based on attenuation and ultrasonic velocity, showed a weak correlation between the predicted quantity of added oil and the actual quantity added to organic argan oil, with determination coefficients (r2) not exceeding 65%. The weak correlation is due to the similar chemical compositions of the oils. These results underscore the value of ultrasonic-statistical analysis for authenticating and ensuring the quality of vegetable oils. However, the limitations highlight the need to refine models for better accuracy. This method can verify oil authenticity in the food industry, ensuring consumer protection and quality standards. Additionally, it offers a quick and simple alternative to traditional methods, reducing costs and improving efficiency in quality control processes.

Abstract Ultrasonic techniques are frequently used in organic molecule conformation analysis. Mixtures of ternary liquid complexes are extensively used for comprehending the strength as well as the characteristics of the interactions between molecules. Experimentally, the thermo physical properties of ternary liquid mixtures such as viscosity (η), density (ρ) and velocity (u) of K-contin, (2-Aminoacetamido)acetic acid and non-aqueous medium were determined over temperature ranges of 298.15, 308.15 and 318.15 K. The experimental data were used to ascertain the thermoacoustic parameters such as free volume, internal pressure, adiabatic compressibility, solvation number, specific acoustic impedance and intermolecular free length. These parameters are more useful for predicting and validating molecular interactions.

Microwave-absorbing suspicious objects (MASOs) found using microwave-induced thermoacoustic imaging (MTI) can be divided into two types—endogenous (such as tumors or hematoceles) and exogenous (such as calculi or foreign bodies). These have different microwave absorption or ultrasonic velocity than normal human tissue, so MTI is efficient in detecting these anomalies. However, the existing MTI techniques can only reflect morphological information, making it difficult to distinguish the type of each anomaly. In this paper, a newly enhanced MTI system composed of a multiple-element ring transducer and a parallel data acquisition system (DAS) is presented. By using ultrasonic velocity and microwave absorption measurements, where the ultrasonic velocity is mainly used as an additional parameter to reflect mechanical characteristics, the type of the detected anomaly can be identified. In our experiments, the MASO can be located through the absorption difference detected by MTI. Due to the use of multiple-element transducers and a parallel DAS, the raw data can be acquired within about 20 ms for a two-dimensional image. Additionally, the ultrasonic velocity of the MASO can be calculated from the time sequence diagram of ultrasound propagation with a maximum time error of 0.084 μs. Apart from distinguishing the type of the anomaly, the proposed ultrasonic velocity-assisted microwave-induced thermoacoustic imaging (US-MTI) system has other advantages, such as being noninvasive, and allowing rapid imaging and a large field of view, which make US-MTI a suitable modality for regular screening.

Investigation of variations in rheological, acoustical and electrical properties of an eco-friendly nanofluids could be a substitute for a coolant/lubricant, in industry 4.0. Researchers in the past two decades have shown a greater interest in exploring the experiential changes of nanofluid based on volume fraction, and temperature suitable for a desired application. The present study observes, the influences of volume fractions of CuO nanoparticles in enriched coconut oil (CO) blended with Moringa oleifera seed oil (MOSO) (3:1). The surface morphology of CuO nanoparticles shows the average particle sizes are in between 11 nm and 70 nm. The X-ray diffraction showed a monoclinic structure without impurities which having crystallite size of 23 nm. Physical properties such as viscosity, shear rate, shear stress, torque and density were observed for the stable nanofluid at three different volume fractions (φ = 0.4, 0.8, and 1.0). The viscosity of the prepared nanofluid was enhanced to 22.1% at φ = 1. Acoustical behaviour was probed to estimate the decrease in ultrasonic wave transmission through nanofluid with upsurge in φ and a novel model equation (with R2 = 0.983) was developed. As an additional application, the defects in machines can be validated with an aid of ultrasonic velocity. The response of dielectric constant (DC) with φ and sustainability is in the range of 2.65–3 at 90 °C supports the usage of nanofluids in energy storage system and a replacement of transformer oil. [ABSTRACT FROM AUTHOR]

Demolition of buildings can generate large amounts of waste concrete, which if used effectively, can help reduce both the extraction of raw materials and carbon emissions. However, the presence of old cement mortar affects the effective use of waste concrete as a recycled fine aggregates. This study aims to remove old mortar adhering to the surface of waste concrete coarse aggregates via thermal-physical treatment. This study involves assessing the thermal-physical treatment technology and comparing the performance of recycled fine aggregates prepared using this technology with that of fully recycled fine aggregates. The results of this study illustrate the effect of the thermal-physical treatment technique on the preparation of recycled fine aggregates from waste concrete and the effect of fully recycled fine aggregates and recycled fine aggregates prepared using this technique on ceramsite concrete. The results revealed that the thermal-physical treatment technology has a positive effect in improving the quality of recycled fine aggregates prepared via the thermal-physical treatment technique. This technique helps to significantly improve the compressive strength, ultrasonic velocity, resistance to sulfate attack, and microstructure of the recycled ceramsite concrete compared with the fully recycled fine aggregate. [ABSTRACT FROM AUTHOR]

Considering the gradual reduction of fossil fuel resources and their role in environmental issues, biodiesel-derived products have received much attention as fuel additives to enhance their properties and reduce emissions. The present work reports the engine performance and emission characteristics for a fuel blend consisting of solketal, a derivative of glycerol and gasoline. In this study, 5–10 vol% solketal was mixed with gasoline by ultrasonic processor to prepare a solketal-gasoline fuel blend. The blending of additives will affect the volumetric transport properties as well as the combustion quality of the fuel. Some important properties like thermal conductivity, surface tension, adiabatic compressibility, relative association, and intermolecular free path length were measured at different temperatures by measuring the ultrasonic velocity in the fuel blend. Four-stroke SI engine performance was studied in terms of brake-specific fuel consumption (BSFC) and brake thermal efficiency (BTE). BSFC increases by 15%, and BTE shows a marginal reduction of about 5.39% at 28.13 N·m torque with a 10% solketal-gasoline blend. The exhaust analysis indicates that CO emissions decrease and NOx and CO2 increase compared to pure gasoline as fuel, the brake thermal efficiency indicates a marginal reduction of about 5.39% for 10% solketal. [ABSTRACT FROM AUTHOR]

Ultrasonic techniques are frequently used in organic molecule conformation analysis. Mixtures of ternary liquid complexes are extensively used for comprehending the strength as well as the characteristics of the interactions between molecules. Experimentally, the thermo physical properties of ternary liquid mixtures such as viscosity (η), density (ρ) and velocity (u) of K-contin, (2-Aminoacetamido)acetic acid and non-aqueous medium were determined over temperature ranges of 298.15, 308.15 and 318.15 K. The experimental data were used to ascertain the thermoacoustic parameters such as free volume, internal pressure, adiabatic compressibility, solvation number, specific acoustic impedance and intermolecular free length. These parameters are more useful for predicting and validating molecular interactions. [ABSTRACT FROM AUTHOR]

Nanoparticles suspended in conventional fluids also named as nanofluids are being researched due to its unique thermal behaviour and its employability as heat transfer fluids. This report details the preparation and stabilization of Al2O3/CuO nanofluids and was analyzed by X-Ray diffraction, SEM and IR respectively. Further the synthesized nanoparticles are dispersed in different volume fractions of ethylene glycol solvent (0.001, 0.003, and 0.005 mass fractions) to prepare nanofluids. The nanofluids were prepared via rigorous stirring and ultrasonic agitation to maintain the stability. Further these nanofluids were prepared without any stabilizer at 2.7 pH. Further the thermal properties were investigated using KD2 Probe analysing unit, which showed that the thermal conductivity increased with higher concentrations of nanofluids. Ultrasonic velocity, yet another property of nanofluids, represents the speed in which sound propagates in a material and depends on density and elasticity of the material. Ultrasonic velocity of nanofluids is important for non-radiative and non-destructive structural analysis and hence the same has been investigated. Results proved that the prepared nanocoolants are stable and hence could be utilized for coolant applications.

Ultrasonic velocity measurements are used to elucidate various aspects of solvation chemistry, including solute–solute and solute–solvent interactions. Herein, an attempt is made to study a behavior of two sweeteners, D-fructose and D-sorbitol, in aqueous and non-aqueous media was attempted. D-fructose is a simple sugar found in many foods and can be consumed by diabetics and people suffering from hypoglycemia. D-Sorbitol is a sugar substitute used in diet foods, sugar-free chewing gum, mints, cough syrups, mouthwash, toothpaste etc., D-sorbitol is an excellent humectant and texturizing agent that is also used in other products such as pharmaceuticals and cosmetics. The interactions between the solute and solvent molecules are explained in terms of the solvation numbers of both aqueous and non-aqueous solutions of D-fructose and D-sorbitol. The viscosity study correlates the viscosity of the solution with solvation; here, density, ultrasonic velocity, and viscosity of aqueous and non-aqueous solutions at various concentrations are measured at different temperatures ranging from 35 to 55 °C. These parameters provide sufficient information on the interaction between molecules that may aid chemists in analyzing the mechanisms of the behavior of D-fructose and D-sorbitol in water and the water–ethanol medium through which they are consumed. The Fourier transforms infrared spectra of pure solvent, salt, and their solutions were recorded and analyzed for confirmation.

A suspended dense graded broken stone road foundation stabilized by cement is a commonly employed material in roadworks, which is vulnerable to harm caused by freezing and thawing processes. This investigation intends to evaluate the laboratory behavior and the characteristics of freezing and thawing process-induced deterioration in a broken stone road foundation stabilized by cement with suspended dense grading, employing mechanical examinations and acoustical methods. The rate of mass loss in the broken stone road foundation stabilized by cement progressively rises, and the rate of decline in the compressive strength could potentially intensify as freezing and thawing processes augment. The modulus of resilience diminishes as freezing and thawing processes progress, and ultrasonic wave velocity also decreases. The patterns of mass loss, compressive strength decline, resilience modulus reduction, and ultrasonic wave velocity alteration adhere to a parabolic fitting relationship with freeze–thaw cycles, with an R2 above 0.95. The curves depicting the relationship of mass, compressive strength, resilience modulus, and ultrasonic wave velocity exhibit a steeper trend significantly after 10–15 cycles, which can be ascribed to the emergence of microcracks and the progression of flaws within the material. The evolution of damage in the broken stone road foundation stabilized by cement is monitored to progress through three distinct stages based on acoustic emission: initial, stationary, and failure. As freezing and thawing processes accumulate to 20 cycles, the length of initial phase correspondingly rises to three times, the length of failure stage diminishes to about one fifth.

The unfrozen water content (UWC) of rocks at low temperature is an important index for evaluating the stability of the rock engineering in cold regions and artificial freezing engineering. This study addresses a new method to estimate the UWC of saturated sandstones at low temperature by using the ultrasonic velocity. Ultrasonic velocity variations can be divided into the normal temperature stage (20 to 0 ℃), quick phase transition stage (0 to −5 ℃) and slow phase transition stage (−5 to −25 ℃). Most increment of ultrasonic velocity is completed in the quick phase transition stage and then turns to be almost a constant in the slow phase transition stage. In addition, the UWC is also measured by using nuclear magnetic resonance (NMR) technology. It is validated that the ultrasonic velocity and UWC have a similar change law against freezing and thawing temperatures. The WE (weighted equation) model is appropriate to estimate the UWC of saturated sandstones, in which the parameters have been accurately determined rather than by data fitting. In addition, a linear relationship between UWC and ultrasonic velocity is built based on pore ice crystallization theory. It is evidenced that this linear function can be adopted to estimate the UWC at any freezing temperature by using P-wave velocity, which is simple, practical, and accurate enough compared with the WE model.

A polemic is given regarding the apparent molar volumes used in examining the molecular interactions between the dissolved tetraalkylammonium iodide, R4NI, salts and organic solvents. The apparent molar volumes of the four R4NI salts dissolved in N,N-dimethylformamide, taken from the authors' earlier studies, were found to vary significantly from one study to another. [ABSTRACT FROM AUTHOR]

Ultrasonic velocity measurements are used to elucidate various aspects of solvation chemistry, including solute– solute and solute–solvent interactions. Herein, an attempt is made to study a behavior of two sweeteners, Dfructose and D-sorbitol, in aqueous and non-aqueous media was attempted. D-fructose is a simple sugar found in many foods and can be consumed by diabetics and people suffering from hypoglycemia. D-Sorbitol is a sugar substitute used in diet foods, sugar-free chewing gum, mints, cough syrups, mouthwash, toothpaste etc., D-sorbitol is an excellent humectant and texturizing agent that is also used in other products such as pharmaceuticals and cosmetics. The interactions between the solute and solvent molecules are explained in terms of the solvation numbers of both aqueous and non-aqueous solutions of D-fructose and D-sorbitol. The viscosity study correlates the viscosity of the solution with solvation; here, density, ultrasonic velocity, and viscosity of aqueous and nonaqueous solutions at various concentrations are measured at different temperatures ranging from 35 to 55 °C. These parameters provide sufficient information on the interaction between molecules that may aid chemists in analyzing the mechanisms of the behavior of D-fructose and D-sorbitol in water and the water–ethanol medium through which they are consumed. The Fourier transforms infrared spectra of pure solvent, salt, and their solutions were recorded and analyzed for confirmation. [ABSTRACT FROM AUTHOR]

The skeleton dense graded cement-stabilized crushed stone base is a widely used material for road construction. However, this material is susceptible to freeze–thaw damage, which can lead to degradation and failure, for which there is still a lack of an in-depth understanding of the freeze–thaw damage characteristics. This study aims to assess the mechanical performance and the freeze–thaw damage characteristics of the cement-stabilized crushed stone base with skeleton dense gradation based on a mechanical test and acoustic technology in a laboratory. There is a gradually increasing trend in the mass loss rate of the base material with an increase in freeze–thaw cycles. The curve steepens significantly after 15 cycles, following a parabola-fitting pattern relationship. The compressive strength of the cement-stabilized crushed stone base also decreased with a parabola-fitting pattern, and the decrease rate may accelerate as the freeze–thaw cycles increase. The resilience modulus of the base material decreased with increasing freeze–thaw cycles, following a parabolic trend. This suggests that the material’s resistance to freeze–thaw damage decreases with increasing cycles. The ultrasonic wave velocity decreased with increasing freeze–thaw cycles, exhibiting a parabolic trend. This decline can be attributed to microcracks and defects developing within the material, offering insights for monitoring and predicting its service life. The damage progression of the cement-stabilized crushed stone base was found to occur in three stages: initial, stationary, and failure. The duration of stage I increased with freeze–thaw cycles, while the duration of stage III decreased. The findings provide valuable insights into the mechanisms and processes of freeze–thaw damage in a cement-stabilized crushed stone base with skeleton dense gradation.

The detection of ductile damage by image-based methods is time-consuming and typically probes only small areas. It is therefore of great interest for various cold forming processes, such as sheet-bulk metal forming, to develop new methods that can be used during the forming process and that enable an efficient detection of ductile damage. In the present study, ductile damage in DC04 was examined using ultrasonic testing. First, different grain sizes were set by heat treatment. Subsequently, the sheet metal was formed by cold rolling. A clear correlation between the average void diameter and the measured ultrasonic velocity could be shown. The ultrasonic velocity showed a clear decrease when the average void size increased because of the increasing forming degree. The ultrasonic measurements were finally employed to calculate a damage parameter D to determine the amount of ductile damage in the microstructure for different grain sizes after cold rolling. [ABSTRACT FROM AUTHOR]

This article reports on the characterization of the "as-fabricated" state of Inconel 718 samples fabricated using laser directed energy deposition (DED). Laser-DED is known to produce complex metastable microstructures that can significantly influence the baseline ultrasonic response compared to conventional processing methods. The present work uses three parameters to characterize the samples: (a) ultrasonic velocity, (b) an attenuation coefficient, and (c) a backscatter coefficient. The baseline ultrasonic response from the DED sample was compared against the ultrasonic properties of conventional IN718 samples reported in the literature. The results suggest that strong grain boundary scattering from large macrograins can lead to attenuation and backscatter values that are significantly higher than conventional samples. Additionally, the results including velocities, attenuation and backscatter coefficients were found to be dependent on the fabrication direction, with the build direction being different from the transverse directions. Finally, destructive analysis was used to develop conjectures to explain the experimentally observed ultrasonic response. [ABSTRACT FROM AUTHOR]

The acoustical investigation of molecular interaction has been performed from the measurement parameters of ultrasonic velocity (U), density (?) and viscosity (Ｕ) of aqueous dextran solution at different temperatures. The thermodynamic and other allied parameters like internal pressure (pi), free volume (p), absorption coefficient or attenuation coefficient (a), Rao's constant (Ro) and Wada's constant (W) have been computed. To understand the structural reorganization of the solute (dextran) and solvent (distilled water) in aqueous solution, concentration and temperature changes of these parameters have been investigated. Differences in ultrasonic velocity and other factors are crucial to comprehending the solute-solvent intra and intermolecular interactions between the constituent molecules. [ABSTRACT FROM AUTHOR]

This study focused on the effect of WC on the ultrasonic properties, thermal and electrical conductivity of WC–Co–Ni–Cr composites. The samples were produced by powder metallurgy method for microstructural, physical, and ultrasonic characterization. Pulse-echo, hot disk, and four probe methods were used to evaluate the ultrasonic properties, thermal and electrical conductivity of WC–Co–Ni–Cr composites with different WC contents, respectively. Experimental results show that thermal conductivity and electrical conductivity of WC–Co–Ni–Cr composites increase linearly with increasing WC content and then decrease rapidly. The reason for this rapid decrease is expressed in the fact that the structure becomes more ceramic as the WC additive ratio increases. The same situation was observed in ultrasonic measurements. As the amount of WC particles in the sample increased, longitudinal and shear wave velocity, attenuation values, and elastic modulus increased.

To study the influence of mineral admixtures on the basic characteristics and high temperature resistance of recycled aggregate concrete, fly ash, iron slag and rice husk ash were used to modify recycled aggregate concrete. High temperature and mechanical tests were carried out. The results show that with the increase of temperature, the density and ultrasonic velocity of the sample continue to decrease; the density and ultrasonic velocity of the sample prepared by the additive method are greater than that of the sample prepared by the alternative method; the compressive strength and relative elastic modulus increase first and then decreases with the increase of the mineral，reaching the maximum at 5%~10%. As the temperature increases, the compressive strength first increases and then decreases, reaching the maximum at 100°C; and when the mineral admixture is added by the additive method, the strength and elastic modulus of the sample are higher. Enhancement of high temperature resistance of recycled aggregate concrete: fly ash>iron slag>rice husk ash. In addition, the concrete density and compressive strength, density and elastic modulus, ultrasonic velocity and compressive strength have a better correlation when using the alternative method; however, the correlation between the various parameters is poor when the additive method is used.

The prediction and prevention· of mine disasters are crucial to identifying the stress and strain state of coal using ultrasonic response characteristics. In this study, ultrasonic testing experiments of primary structure coal samples under uniaxial loading were conducted using a low-frequency rock physics measuring device. Based on the experimental results, the study focused on analyzing the relationship of the stress–strain state of coal samples with the ultrasonic velocity and quality factor of coal samples during stress loading, and exploring the influence mechanism of ultrasonic propagation in coal during stress loading. The results demonstrated that the stress-loading process of coal samples falls into the elastic deformation stage and the plastic deformation stage. In the elastic deformation stage, the ultrasonic velocity and the quality factor of the coal sample increased with the increase in the coal axial strain. In the plastic deformation stage, the ultrasonic velocity and quality factor of coal samples decreased as the axial strain of coal samples increased. Coal porosity was the fundamental factor affecting the coal wave velocity variation and the coal quality factor variation. In the elastic deformation stage, increased coal axial stress was accompanied by decreased coal porosity, contributing to the increase in coal wave velocity and coal quality factor. In the plastic deformation stage, the increase in the coal axial strain increased coal porosity and thus curtailed the wave velocity and quality factor of coal. Significant differences were observed in ultrasonic response characteristics of coal under various stress and strain states. The research results can lay a theoretical foundation for the safe and efficient development of coal resources and the prevention and control of mine disasters. [ABSTRACT FROM AUTHOR]

This study aimed to apply an ultrasonic pulse-echo system to characterize thermally oxidized rapeseed oil. After 60 h of heating treatment (165 ± 5 °C), the physicochemical (density, viscosity, acid value, iodine value and polar compounds) and acoustic properties (velocity, acoustic impedance, maximum amplitude of the first echo, difference in amplitude, and area under the curve) of rapeseed oil were measured. Support vector machine, random forest (RF), and backpropagation neural network algorithms were used to establish quantitative prediction models for viscosity and polar compounds based on the acoustic properties of rapeseed oil. The results indicated significant correlations between acoustic impedance and viscosity (R = 0.70), as well as between acoustic impedance and polar compounds (R = 0.79). Heating treatment reduced oil unsaturation and led to the formation of oxidative and polymeric compounds, which in turn increased the velocity and impedance, while decreasing the other three acoustic features. The RF model yielded the best performance in predicting viscosity (R2 = 0.7944) and polar compounds (R2 = 0.8385). These findings highlight that ultrasonic technology not only accurately predicts key quality parameters, but also provides a rapid, non-destructive, and cost-effective alternative to traditional methods for characterizing thermally oxidized rapeseed oil. • Significant correlations between acoustic and physicochemical indicators were found. • Variations in ultrasonic indicators are linked to intermolecular structure changes. • Random forest model exhibits the highest accuracy for viscosity and polar compounds. • Ultrasonic technology could characterize thermally oxidized rapeseed oils. [ABSTRACT FROM AUTHOR]

The rapid and accurate identification of the physical characteristics of coal by means of ultrasonic detection is of great significance to ensure safe mining of coal and efficient development of coal seam methane. In this paper, the ultrasonic velocity testing experiments of coal during gas adsorption and desorption were carried out, utilizing a low frequency petrophysical measurement device with primary and fractured coal as the research objects. The variations in the elastic mechanical parameters and ultrasonic velocity of coal samples were analyzed to elucidate the influence mechanism that gas adsorption and desorption have on them. During gas adsorption and desorption, the longitudinal wave velocity of the primary structure coal varies from 1990 m/s to 2200 m/s, and the transverse wave velocity varies from 1075 m/s to 1160 m/s, while the longitudinal wave velocity of the fractured structure coal varies from 1540 m/s to 1950 m/s, and the transverse wave velocity varies from 800 m/s to 1000 m/s. The elastic modulus and wave velocities, in both directions of the primary structural coal, were higher than those of the fractured structural coal. In comparison to the fractured structural coal, the main structural coal had a lower Poisson's ratio. In addition, the spread of the elastic mechanical parameters and wave velocities, in both the longitudinal and transverse directions, was more pronounced in the fracture−structured coal than in the primary−structured coal. During gas adsorption and desorption, the speed of the coal's longitudinal waves increased, and then decreased, due to the combined effect of gas adsorption expansion and pore gas pressure compression matrix effect. For this experiment, the maximum longitudinal wave velocity of the coal occurred at a gas pressure of 1.5 MPa. Primary structural coal has a longitudinal wave speed of 2103 m/s, whereas fragmented structural coal has a speed of 1925 m/s. The variation in the shear wave velocity of the coal is controlled only by the gas adsorption expansion effects. The shear wave velocity increases during gas adsorption and decreases during gas desorption. With the change of gas pressure, the longitudinal wave velocity can increase by 23.34%, and the shear wave velocity can increase by 17.97%. Coal undergoes changes to both its Poisson's ratio and elastic modulus as a result of gas adsorption and desorption; these modifications are analogous to the velocity of longitudinal and shear waves, respectively. [ABSTRACT FROM AUTHOR]

In this study we have tried to model ultrasonic velocity of 15 halogen containing organic liquids. For this purpose, we have used physicochemical and topological parameters. We found that the ultrasonic velocity can be modelled using both the parameters. The best model obtained, after regression analysis, contains surface tension, density and second order-valence connectivity index. The R2 value comes out to be 0.9416. The model has been tested for any kind of defect and observed that the proposed model is free from any defect. [ABSTRACT FROM AUTHOR]

As the amount of aged pavement increases, functional damage, such as spalling, occurs frequently on Portland Cement Concrete pavement (PCC) in South Korea. However, the existing management method does not properly reflect the scope of deterioration of the pavement causing early damage. To overcome the problem of the existing repair method, this study evaluated the deterioration of functional damage on the surface of the slab as soundness through ultrasonic velocity measurement method among non-destructive testing (NDT) techniques and suggested a method to estimate the depth of deterioration. To develop a method for estimating the depth of the deterioration a slab, a preliminary investigation was conducted to check the range of ultrasonic velocity of concrete pavement in South Korea and to evaluate the variability of NDT equipment. Based on the ultrasonic velocity, the sound rating of concrete pavement was graded from 5 for "very good" to 0 for "very poor", and the tendency of the ultrasonic velocity to increase according to the depth of the deteriorated areas was confirmed. [ABSTRACT FROM AUTHOR]

Ultrasonic velocity measurements, density measurements, and viscometric studies were conducted for the ternary mixture of pyridine and toluene separately with N, Ndimethylformamide (DMF) in butanol, at different temperatures and for different concentrations of component liquids. Using these basic experimental data, various acoustic and thermodynamic parameters, such as adiabatic compressibility (β), free length (Lf,), free volume (Vf), etc. were calculated. Also, Excess thermo-acoustical parameters were calculated from the experimentally measured data. The outcomes were expressed in terms of the molecular interactions and the variations in parameters under varying solute concentrations. A comparative study is discussed. Variation in the above parameters for the different mixtures is indicative of the nature of the interactions between the components in the liquid mixture. Concluding remarks regarding intermolecular interactions are provided. [ABSTRACT FROM AUTHOR]

Non-destructive pulse-echo ultrasonic testing was conducted to measure ultrasonic parameters, i.e. longitudinal velocity (Vl), shear velocity (Vs) and attenuation coefficient (α) in Al–Al2O3 nanocomposites. Elastic constants were also determined using the relationship between Vl and Vs. The aim was to reveal the correlation between ultrasonic parameters and the microstructural features of Al–Al2O3 nanocomposites. The effect of addition of Al2O3 nanoparticles on the Vl and Vs velocities is mainly attributed to variation in the elastic modulus of Al–Al2O3 nanocomposites. Both Vl and Vs velocities and Young's modulus (E) were found to vary approximately in linear fashion with the increase of Al2O3 content. A considerable effect of milling process on Vl and Vs velocities was revealed, where they increase by increasing the milling time. The increment of Vl and Vs is owing to refinement of Al particles, homogenous dispersion of Al2O3 and particularly reducing porosity by proceeding milling time. In addition, increasing of Al2O3 content, better dispersion uniformity of Al2O3 and refinement of Al particles contribute to increase α values. Elastic constants were found to vary in the same manner as ultrasonic velocities. Interestingly, the improvement in E values by increasing Al2O3 content and milling time is attained, while the ductility did not change significantly.

Streptomycin is an antibiotic medication used to treat a number of bacterial infections. In the present study ultrasonic velocity (U), density (ρ) and viscosity (η) have been measured at frequency 1 MHz in the binary mixtures. The binary mixtures of streptomycin with water in the concentration range (0.1 to 0.0125%) at 303 K, 308 K, and 313 K using a multifrequency ultrasonic interferometer. The measured value of ultrasonic velocity, density and viscosity have been used to estimate the acoustical parameters namely adiabatic compressibility (βa), relaxation time (τ), acoustic impedance (z), free length (Lf), free volume (Vf) and internal pressure (Pi), Wada’s constant(W), Rao’s constant (R) to investigate the nature and strength of molecular interaction in the binary mixture with water. The obtained results support the occurrence of complex formation, molecular association through intermolecular hydrogen bonding in the binary liquid mixtures. DOI: http://dx.doi.org/10.17807/orbital.v13i4.1465

This paper presents results of application of Ultrasonic Waves UW in civil engineering. The measurement has been performed by ultrasonic reflection technique using a transducer with central frequency 0,5MHz. Several methods of analysis and signal processing have been applied to detect the position of reflections and to measure the time of flight between two echoes related to the reflection at the mortar interfaces. The experiments performed in the laboratory are carried to determine the ultrasonic velocity of the wave backscattered by samples. This allowed determining the ultrasonic velocity of UW in the mortar in order to deduce the durability of each mortar according to its microstructure. The objective is to make a comparative study of the various methods of analysis of the ultrasonic signals as: Continuous Wavelet Transform (CWT), Wigner Ville (WVD), Pseudo Wigner–Ville distribution (PWVD), Smoothed Pseudo Wigner–Ville Distribution (SPWVD) and Hilbert Transform (HT).

The detection of ductile damage by image-based methods is time-consuming and typically probes only small areas. It is therefore of great interest for various cold forming processes, such as sheet-bulk metal forming, to develop new methods that can be used during the forming process and that enable an efficient detection of ductile damage. In the present study, ductile damage in DC04 was examined using ultrasonic testing. First, different grain sizes were set by heat treatment. Subsequently, the sheet metal was formed by cold rolling. A clear correlation between the average void diameter and the measured ultrasonic velocity could be shown. The ultrasonic velocity showed a clear decrease when the average void size increased because of the increasing forming degree. The ultrasonic measurements were finally employed to calculate a damage parameter D to determine the amount of ductile damage in the microstructure for different grain sizes after cold rolling.

This article reports on the characterization of the “as-fabricated” state of Inconel 718 samples fabricated using laser directed energy deposition (DED). Laser-DED is known to produce complex metastable microstructures that can significantly influence the baseline ultrasonic response compared to conventional processing methods. The present work uses three parameters to characterize the samples: (a) ultrasonic velocity, (b) an attenuation coefficient, and (c) a backscatter coefficient. The baseline ultrasonic response from the DED sample was compared against the ultrasonic properties of conventional IN718 samples reported in the literature. The results suggest that strong grain boundary scattering from large macrograins can lead to attenuation and backscatter values that are significantly higher than conventional samples. Additionally, the results including velocities, attenuation and backscatter coefficients were found to be dependent on the fabrication direction, with the build direction being different from the transverse directions. Finally, destructive analysis was used to develop conjectures to explain the experimentally observed ultrasonic response.

Ultrasound is a reliable non-destructive method commonly used to evaluate the state of a piece of wood. The effect of the moisture content (MC) on the timber wave velocity, which is different depending on the wood species, must be considered. MC adjustment factors are important if accurate and comparable results are to be achieved. Thus, the goal of this study is to define a model that allows obtaining the adjustment factor to predict the standard velocity (12% of MC (V12) from velocity obtained at different MC for two Costa Rican commercial species: Tectona grandis L.F (teak) and Cupressus lusitanica M. (cypress). This effect was studied on small clean specimens during the desorption stages, from the fiber saturation point to the oven-dry state, controlling the specimen's mass and MC on 62 specimens. With this data, the rate of change in ultrasound velocity per MC was modeled. Thus, the applicability of already published moisture adjustment models for conifers and hardwood tropical species was proved. The results showed that the proposed model coefficients adjust better than the ones obtained from the wood science literature, which makes them suitable to describe ultrasound velocity in different moisture conditions (VH). [ABSTRACT FROM AUTHOR]

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Density (ρ) and speed of sound (u) values of L-Citrulline in aqueous solution, 0.06 mol·kg−1 aqueous Urea and aqueous 0.06 mol·kg−1 Dextrose solutions have been measured at T = (288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K within the concentration range of (0.02 to 0.2) mol·kg−1.These measurements have been performed to evaluate some important parameters, viz, apparent molar volume of solute (Vϕ), limiting apparent molar volume of solute (Vϕ0), limiting apparent molar volume of transfer (ΔtrVϕ0), limiting apparent molar expansivity(Eϕ0), thermal expansion coefficient (α*), Hepler's constant (∂2Vϕ0∂T2), isentropic compressibility (κs), apparent molar compressibility (Ks,ϕ), limiting apparent molar compressibility (Ks,ϕ0), limiting apparent molar isentropic compressibility of transfer (ΔtrKs,ϕ0)and hydration number(ηH) . The results have been interpreted in terms of different interactions taking place in aqueous solutions.

The disturbance due to coal mining causes the surrounding rock to undergo a complex process of stress changes during which the axial pressure and the confining pressure usually change accordingly at the same time. Existing studies generally investigated this process from a static perspective, which was not rigorous. The mechanical characterization of rock is very important to understand the failure of rock mass and the safety of mining during mining disturbance. Based on theoretical analysis, we conducted axial loading and radial unloading tests on the cracked sandstone, which was combined with the ultrasonic testing technology to examine its failure rules and to characterize and analyze its failure process using longitudinal wave velocity. The results demonstrated that crack length and angle had a significant impact on the strength and mechanical properties of sandstone, and the former had a greater impact on the strength of sandstone than the latter. As the crack length increased, the strength, elastic modulus, and deformation modulus of sandstone decreased, and the strength of sandstone increased as the crack angle increased. Elastic and deformation moduli first decreased and then increased. Furthermore, Poisson’s ratio increased slowly, then decreased slowly, and finally increased rapidly as the lateral pressure coefficient diminished, and Poisson’s ratio was more sensitive to changes in the angle. In this study, the change of longitudinal wave velocity reflected the whole process of sandstone failure. When the wave velocity was stable, the rock was at the yield limit point. Moreover, when the wave velocity was unstable, the sandstone was in a progressive failure period, and as a result, the wave velocity decreased and the sandstone cracked.

Oils are commonly used in cooking as a frying medium which has been constantly subjected to different levels of heating. In this work, we have considered the most commonly used oils namely peanut oil and corn oil. Quality analyses of corn and peanut oils were made by relating macroscopic properties (ultrasonic velocity, viscosity, and density) to microscopic parameters (intermolecular free length, adiabatic compressibility etc.,) by subjecting them to six cycles of heating (190 ˚C). Variation in the mentioned property indexes, the degree of degradation and reusability for the next heating cycle that could be used in the food industry and processing were monitored. Using Newton-Laplace and Wood’s equation, the adiabatic compressibility, acoustic impedance, and intermolecular free length of the oil were estimated from the experimental data. Ultrasonic velocity was observed linearly as related to viscosity with the dependency factor (R2 = 0.932). With the aid of experiential data, the physical thermodynamic parameters, particularly particle size, packing factor, chemical potential, and L-J potential were computed. A high correlation factor was observed by fitting ultrasonic velocity, viscosity, and density to Parthasarathy and Bakshi, and Rodenbush equations. In the study, ultrasonic velocity, a macroscopic parameter, could be decoded to determine the microscopic variations in oil subjected to different temperatures in an industrial application.

The thermal conductivity of Al2O3-water nanofluid (NF) was investigated in this study utilizing ultrasonic velocity. The change in thermal conductivity was calculated by increasing the weight fraction from 0.01% to 1% for every 10°C elevation in the temperature range of 25-65°C. The thermal conductivity of NF augmented with an enhancement in nanoparticle concentration and rise in temperature. The thermal conductivity of NF was higher than that of basefluid. Finally, the experimental results were compared with classical thermal conductivity models and the thermal conductivity enhancement coefficient was further used to investigate thermal conductivity augmentation. [ABSTRACT FROM AUTHOR]

The ultrasonic velocity of benzoic acid and substituted benzoic acids such as para chloro benzoic acid, para nitro benzoic acid and meta nitro benzoic acid in ethanol-water binary solvent mixtures of several compositions were evaluated. It finds immense applications in the field of several technological and industrial processes such as petrochemical, pharmaceutical and in the manufacture of dyes. The results of ultrasonic velocity determination are remarkably important in the determination of liquid mixtures that are made up of polar and non-polar compounds. The structural modifications of ethanol get into a 3-D network of linkages made up of hydrogen bonds in liquid mixtures. In the present study, it is inferred that a weak molecular association exists between ethanol and the substituted benzoic acids through weak dipole-dipole interactions. The probability of the development of donoracceptor complexes has also been examined and subsequently discussed. In addition, the effect of substituents like the nitro and the chloro group at the para and meta positions has also been interpreted. [ABSTRACT FROM AUTHOR]

Oils are commonly used in cooking as a frying medium which has been constantly subjected to different levels of heating. In this work, we have considered the most commonly used oils namely peanut oil and corn oil. Quality analyses of corn and peanut oils were made by relating macroscopic properties (ultrasonic velocity, viscosity, and density) to microscopic parameters (intermolecular free length, adiabatic compressibility etc.,) by subjecting them to six cycles of heating (190 ËšC). Variation in the mentioned property indexes, the degree of degradation and reusability for the next heating cycle that could be used in the food industry and processing were monitored. Using Newton-Laplace and Wood's equation, the adiabatic compressibility, acoustic impedance, and intermolecular free length of the oil were estimated from the experimental data. Ultrasonic velocity was observed linearly as related to viscosity with the dependency factor (R² = 0.932). With the aid of experiential data, the physical thermodynamic parameters, particularly particle size, packing factor, chemical potential, and L-J potential were computed. A high correlation factor was observed by fitting ultrasonic velocity, viscosity, and density to Parthasarathy and Bakshi, and Rodenbush equations. In the study, ultrasonic velocity, a macroscopic parameter, could be decoded to determine the microscopic variations in oil subjected to different temperatures in an industrial application. [ABSTRACT FROM AUTHOR]

As the amount of aged pavement increases, functional damage, such as spalling, occurs frequently on Portland Cement Concrete pavement (PCC) in South Korea. However, the existing management method does not properly reflect the scope of deterioration of the pavement causing early damage. To overcome the problem of the existing repair method, this study evaluated the deterioration of functional damage on the surface of the slab as soundness through ultrasonic velocity measurement method among non-destructive testing (NDT) techniques and suggested a method to estimate the depth of deterioration. To develop a method for estimating the depth of the deterioration a slab, a preliminary investigation was conducted to check the range of ultrasonic velocity of concrete pavement in South Korea and to evaluate the variability of NDT equipment. Based on the ultrasonic velocity, the sound rating of concrete pavement was graded from 5 for “very good” to 0 for “very poor”, and the tendency of the ultrasonic velocity to increase according to the depth of the deteriorated areas was confirmed.