Ultrasonic Speed Research Articles

Ultrasonic Characterization of Porosity in Components Made by Binder Jet Additive Manufacturing

Binder jet metallic additive manufacturing (AM) is a popular alternative to powder bed fusion and directed energy deposition because of lower costs, elimination of thermal cycling, and lower energy consumption. However, like other metallic AM processes, binder jetting is prone to defects like porosity, which decreases the adoption of binder-jetted parts. Binder-jetted parts are sometimes infiltrated with a low melting temperature metal to fill pores during sintering; however, the infiltration is impacted by the part geometry and infiltration environment, which can cause infill nonuniformity. Furthermore, using an infiltration metal creates a complicated multiphase microstructure substantially different than common wrought materials and alloys. To bring insight to the binder jet/infiltration process toward part qualification and improved part quality, spatially dependent ultrasonic wave speed and attenuation techniques are being applied to help characterize and map porosity in parts made by binder jet AM. In this paper, measurements are conducted on binder-jetted stainless steel and stainless steel infiltrated with bronze samples. X-ray computed tomography (XCT) is used to provide an assessment of porosity.

Ultrasonic scattering predictions of two-phase polycrystalline materials based on digital microstructures

Many materials found in nature and used in industry consist of multiple phases, and the mechanical performance of such materials is controlled by their material organization. Ultrasonic scattering is one approach to characterize these microstructures nondestructively. In this presentation, previous ultrasonic scattering theories for two-phase materials are discussed and implemented using discrete synthetic three-dimensional microstructures as a means to assess the material statistics. These models predict the ultrasonic wave speed, attenuation, and diffuse ultrasonic backscatter with respect to the volume fraction and grain size distribution of each constituent. The computational approach is then focused on predictions for samples created using spark plasma sintering (SPS) of Cu and Fe powders with varying volume fractions as well as pure Cu and pure Fe samples. DREAM.3D is used to generate digital synthetics representative of the SPS samples as characterized using electron backscatter diffraction (EBSD). A set of 30 realizations for each volume fraction is used for each to quantify the statistical variations expected. The combined theoretical and computational model is used to study the dependence of ultrasonic wave propagation on the material organization for these two-phase materials. [Work supported by Air Force Research Laboratory (AFRL) under prime contract FA8650-15-D-5231.]

Two-dimensional mapping of the ultrasonic attenuation and speed of sound in brain

Brain is inhomogeneous due to its composition of different tissue types (gray and white matter), anatomical structures (e.g. thalamus and cerebellum), and cavities in the brain (ventricles). These inhomogeneities lead to spatial variations in the ultrasonic properties of the organ. The goal of this study is to characterize the spatial variation of the speed of ultrasound and frequency slope of attenuation in fixed sheep brain. 1-cm-thick slices of tissue from the coronal, sagittal and transverse cardinal planes were prepared from 12 brains. Ultrasonic measurements were performed using broadband transducers with center frequencies of 3.5, 5.0, 7.5 and 10 MHz. By mechanically scanning the transducers over the specimens, two-dimensional maps of the speed of sound (SOS) and frequency slope of attenuation (FSA) were produced. Measured values for the spatial mean and standard deviation of FSA ranged between 0.59 and 0.81 dB/cm·MHz and 0.29–0.60 dB/cm·MHz, respectively, depending on the specimen and transducer frequency. Measured values for the spatial mean and standard deviation of SOS ranged from 1532–1541 m/s and 10–14 m/s, respectively. Detailed, two-dimensional maps of FSA and SOS were produced, representing the first such characterization of the spatial variation of the ultrasonic properties of normal mammalian brain.

Studies of Mixing Properties of Binary Systems of 2-Butoxy Ethanol with Amines at 298.15, 303.15, and 308.15 K

The nature of interaction of binary liquid mixtures of 2-butoxy ethanol with amines, namely, diisopropylamine, dibutylamine, and tributylamine, has been examined using the experimentally measured values of density (ρ), ultrasonic speed (u), and viscosity (η) over the temperature range from 298.15 to 308.15 K, in the present discussion. Using the experimentally measured values, various excess and deviation properties have been evaluated and discussed in terms of interaction among the studied binary mixtures. Strong intermolecular interaction among unlike components of binary mixtures is confirmed by these calculated properties. The order of the magnitude of these properties gives an insight into the order of interaction of mixtures of 2-butoxy ethanol with amines. Excess and deviation properties have been correlated with composition using the Redlich–Kister polynomial. The correlation ability of various viscosity models has also been compared. The Fourier transform infrared spectra of these liquid mixtures have also been studied at room temperature.

Quantitative Sound Speed Imaging of Cortical Bone and Soft Tissue: Results From Observational Data Sets.

This work presents the first quantitative ultrasonic sound speed images of ex vivo limb cross-sections containing both soft tissue and bone using Full Waveform Inversion (FWI) with level set (LS) and travel time regularization. The estimated bulk sound speed of bone and soft tissue are within 10% and 1%, respectively, of ground truth estimates. The sound speed imagery shows muscle, connective tissue and bone features. Typically, ultrasound tomography (UST) using FWI is applied to imaging breast tissue properties (e.g. sound speed and density) that correlate with cancer. With further development, UST systems have the potential to deliver volumetric operator independent tissue property images of limbs with non-ionizing and portable hardware platforms. This work addresses the algorithmic challenges of imaging the sound speed of bone and soft tissue by combining FWI with LS regularization and travel time methods to recover soft tissue and bone sound speed with improved accuracy and reduced soft tissue artifacts when compared to conventional FWI. The value of leveraging LS and travel time methods is realized by evidence of improved bone geometry estimates as well as promising convergence properties and reduced risk of final model errors due to un-modeled shear wave propagation. Ex vivo bulk measurements of sound speed and MRI cross-sections validates the final inversion results.

Effect of Gravel Content on Mechanical Performance and Porous Structure of Concrete

Concrete is the most widely used material in the field of civil engineering. In order to obtain a strong and durable concrete, it is necessary to study the various parameters entering into its formulation. Mainly the elements forming the concrete skeleton, in particular the gravel content. The transfer of water into concrete directly affects its durability. This transfer is linked to the porous structure and to the continuity of the pores in the concrete. This research studies the effect of gravel content on compressive strength, porosity accessible to water, depth of water penetration and ultrasonic velocity of concrete samples. The study includes 15 types of concrete made by varying the gravel-sand ratio (G/S), 0, 1, 1.5, 2 and 2.5. The cement dosage is taken equal to 150, 250 and 350 Kg/m3. The tests are carried out on cubic samples 10x10x10 cm3 and 15x15x15 cm3 after storage in water for 28 days. The experimental results obtained show that the gravel-sand ratio (G/S) affects the mechanical strength and the porous structure of concrete. Increasing the gravel content in concrete leads to an increase in mechanical strength and ultrasonic speed. However, a high gravel content results in a reduction in the porosity accessible to water and the depth of water penetration.

Research and development of mine high precision wind speed sensor and temperature correction

According to the requirements of mine production for ventilation monitoring system, an ultrasonic wind speed sensor with high precision and low starting wind speed is developed. Based on the measurement principle of ultrasonic time difference method, an ultrasonic wind speed sensor is designed. The propagation speed of ultrasonic in the air is superimposed with the wind flow speed. The propagation speed is accelerated in the along wind flow direction and slowed down in the counter wind flow direction. Under certain detection conditions, it corresponds to the wind speed function, and the accurate wind speed can be calculated. Through the analysis of the relationship between ultrasonic speed and temperature, it is proposed to correct the ultrasonic propagation speed through temperature compensation. Through experimental research, it is found that eliminating the measured value of wind speed with the difference between ultrasonic temperature and air temperature greater than 1 °C can improve the measurement accuracy.

Investigation of the inter-ionic interactions of an imidazolium-based ionic liquid with the aqueous solutions of tripotassium citrate and trisodium citrate through volumetric, acoustic and FTIR routes

Volumetric, acoustic and spectroscopic characteristics of an imidazolium-based ionic liquid, 1-Butyl-3-methylimidazolium chloride ([bmim][Cl]) in water and aqueous solutions of tri-potassium citrate, K3Cit, and tri-sodium citrate, Na3Cit were studied at five different temperatures T = (298.15 K, 303.15 K, 308.15 K, 313.15Kand 318.15 K) and atmospheric pressure (0.1Mpa). The apparent molar volume,Vϕ, and apparent molar compressibility, Kϕ,S were computed from the experimental data of densities and ultrasonic speeds. The derived properties such as standard partial molar volume, Vϕ0 , partial molar compressibilities, Kϕ,S0, limiting apparent molar expansivity, Eϕ0, and their corresponding transfer volumes, ΔtrVϕ0, transfer compressibilities, ΔtrKϕ,S0, of [bmim][Cl] from water to aqueous potassium/sodium citrate solutions were also determined. The transfer properties have been used to discuss the solute-solvent interactions that exist in the solutions. The positive value of Hepler’s constant indicates that the IL has structure-making ability in the studied solutions. In addition, FTIR spectroscopy was executed on the systems. Based on these data, the predominant molecular interactions occurring between [bmim][Cl] and water and in between [bmim][Cl] and K3Cit/Na3Cit were found to be hydrogen bonds.

Analysis of Platen Superheater Tube Degradation in Thermal Power Plants via Destructive/Non-Destructive Characteristic Evaluation

Coal-fired power plants operating under Korea’s standard supercritical pressure operate in a high-temperature environment, with steam temperatures reaching 540 °C. A standard coal-fired power plant has a 30-year design life, and lifespan diagnosis is performed on facilities that have operated for more than 100,000 h or 20 years. Visual inspection, thickness measurements, and hardness measurements in the field are used to assess the degree of material degradation at the time of diagnosis. In this study, aging degradation was assessed using an electromagnetic acoustic transducer to measure the change in transverse ultrasonic propagation speed, and the results were compared to microstructural analysis and tensile test results. Based on the experimental results, it was found that the boiler tube exposed to a high-temperature environment during long-term boiler operation was degraded and damaged, the ultrasonic wave velocity was reduced, and the microstructural grains were coarsened. It was also confirmed through tensile testing that the tensile and yield strengths increased with degradation. Our findings prove that the degree of change in mechanical properties as a function of the material’s degradation state is proportional to the change in ultrasonic wave velocity.

Analysing the molecular interactions of ternary (lactose + water + tributylmethylammonium chloride) solutions at different temperatures via physicochemical methods

The interactions of lactose with tributylmethylammonium chloride (Bu3MeNCl) as the function of temperature have been studied by amalgamation of volumetric, acoustic and viscometric methods. Density, ultrasonic speed, and viscosity for varying concentrations of lactose in water and in (0.020, 0.039, 0.059, 0.079) mol.kg−1 aqueous solutions of Bu3MeNCl have been determined at five distinct temperatures (T = 293.15–313.15) K. These experimental values have been used to calculate apparent molar volume, Vϕ, limiting apparent molar volume, V0ϕ, apparent molar isentropic compression, Kϕ,s, limiting apparent molar isentropic compression, K0ϕ,s, viscosity B-coefficient, their transfer values, pair and triplet interaction coefficients, and hydration number nH. The Gibbs free energy of activation for solvent (Δµ01#) and Gibbs free energy of activation for lactose (Δµ02#) in water and in aqueous solutions of Bu3MeNCl have also been assessed and the obtained results support the outcome of volumetric, acoustic and viscometric parameters. These parameters provide better understanding of molecular interactions like solute-solute, solute-solvent interactions present in the systems. Further, it helps in determining structural and functional properties of studied systems and acquired results revealed that the solutions are characterized predominantly by solute-solvent interactions. Also, the values of second derivative of limiting apparent molar volume with respect to temperature indicated that the lactose monohydrate behaves as a structure maker in aqueous tributylmethylammonium chloride solutions.

Wind speed sensor data processing based on Kaman Vortex Street principle

Wind speed is one of the important monitoring parameters to ensure mine safety. The commonly used mine wind speed sensor can be divided into ultrasonic type, impeller type and hot wire type according to the design principle. The accuracy of the latter two methods is not high enough because they are susceptible to steam and coal dust in mines. The ultrasonic wind speed sensor has better measuring accuracy. In this paper, ultrasonic wind speed sensor, ultrasonic sending and receiving circuit combined with ADC sampling function of the chip, to obtain the received ultrasonic amplitude change data, statistics of ultrasonic waveform changes caused by blowing, according to the number of changes in the wind speed frequency, and then calculate the real-time wind speed.

Correlation between Mechanical and Acoustic Properties of Deformable Metals

In this work, correlations between ultrasonic speed, strength, and plasticity are studied in Fe–18 wt % Cr–10 wt% Ni alloy under uniaxial tension. Special attention is paid to the effect of static loading on acoustic characteristics and destruction parameters of alloy. To provide non-destructive testing of structural state and mechanical parameters of the material under consideration, its acoustic and mechanical properties are finally studied in a temperature range of 180 K ≤ T ≤ 318 K

Ultrasonic, Refractometry, FT-IR and DFT Studies on Hydrogen Bonding Interactions of Ethylene Glycol/Hexanol Binary Mixtures

The density (ρ), ultrasonic velocity (U), viscosity (η) and refractometry (nD) measurements are performed on the ethylene glycol/hexanol binary liquid mixtures in the range of temperatures 298.15-323.15 K. Various parameters such as adiabatic compressibility (β), acoustic impedance (Z), intermolecular free length (Lf), internal pressure (π) and relaxation time (τ) were calculated based on the experimentally determined values. The excess parameters were calculated to interpret the hydrogen bond networks and environment associated with the liquid solution. The interaction energy between the mixture components is analyzed using the DFT-B3LYP calculations using 6-311+G(d,p), 6-311++G(d,p) basis sets. The FT-IR spectra support the hydrogen bond in the system. The optimization energy, dipole moment of the components were also represented to correlate the measured parameters. The various theories of ultrasonic velocities and mixing rules for refractive index values were also attempted to estimate the ultrasonic speed, refractive index values of the ethylene glycol/hexanol binary system.

Thermo-physical properties of 1,3-Diaminopropane + alkyl acetate (C1-C4) liquid mixtures: Investigation of molecular interactions by insight of IR spectroscopy and DFT studies

The density (ρ) and speed of sound (u) data of 1,3-Diaminopropane (1,3-DAP) (1) + alkyl acetate (AAc) (C1-C4) (2) mixtures at the temperatures (298.15, 303.15, 308.15, 313.15, and 318.15) K and pressure 0.1 MPa were measured. ρ and u data have been used to calculate excess molar volume (VmE), excess molar isentropic compressibility (ksE), excess ultrasonic speed (uE), excess free volume (VfE), excess available volume (VaE) and excess intermolecular free length (LfE). The result of speed of sound have been analyzed in term of various correlations like Nomoto, Van Dael, Impedance dependence and Schaaff's collision factor theory at temperature 298.15 K. The calculated deviation and excess properties are well fitted with Redlich-Kister polynomial equation and further results were analyzed with the help of the structural, inter and intramolecular interaction aspects. IR spectra of the liquid mixture supported the intermolecular interaction between the 1,3-DAP and AAc molecules through shifting of the position of the stretching frequency of some specific functional groups. The results obtained from DFT studies clearly indicates the formation of strong intermolecular interaction between 1,3-DAP and AAc.

Hydration-Strength-Workability-Durability of Binary, Ternary, and Quaternary Composite Pastes.

At present, reducing carbon emissions is an urgent problem that needs to be solved in the cement industry. This study used three mineral admixtures materials: limestone powder (0–10%), metakaolin (0–15%), and fly ash (0–30%). Binary, ternary, and quaternary pastes were prepared, and the specimens’ workability, compressive strength, ultrasonic pulse speed, surface resistivity, and the heat of hydration were studied; X-ray diffraction and attenuated total reflection Fourier transform infrared tests were conducted. In addition, the influence of supplementary cementitious materials on the compressive strength and durability of the blended paste and the sustainable development of the quaternary-blended paste was analyzed. The experimental results are summarized as follows: (1) metakaolin can reduce the workability of cement paste; (2) the addition of alternative materials can promote cement hydration and help improve long-term compressive strength; (3) surface resistivity tests show that adding alternative materials can increase the value of surface resistivity; (4) the quaternary-blended paste can greatly reduce the accumulated heat of hydration; (5) increasing the amount of supplementary cementitious materials can effectively reduce carbon emissions compared with pure cement paste. In summary, the quaternary-blended paste has great advantages in terms of durability and sustainability and has good development prospects.

Minimum Variance Algorithm-Based Correlation Analysis between Body Mass Index and the Malignant Degree of Prostate Cancer Mediated under Ultrasound Images

This study was to explore the correlation between the malignant degree of prostate cancer (PCa) and body mass index (BMI) mediated by ultrasound images under multioperator algorithm (MOA) based on minimum variance (MV) algorithm. MOA was established by optimizing the smoothing technique and diagonal loading algorithms of MV, and its quality and processing speed of ultrasound images were compared with other algorithms. Ninety two patients were selected as the subjects investigated, who had transrectal prostate biopsy mediated by ultrasound to be diagnosed as PCa in the hospital. Based on Gleason score and prostate specific antigen (PSA) value, all patients were divided into a high-risk PCa group (a high-risk group) and a non-high-risk PCa group (a non-high-risk group). The proportion of obese patients in the two groups was compared. The logistic regression analysis method was applied to analyze related factors of PCa development, and Pearson correlation was for analyzing the correlation between Gleason score and BMI of patients. The results showed that the number of patients in the high-risk group was greater than that of the non-high-risk group ( P < 0.05), while the proportion of nonobese patients in the non-high-risk group was markedly higher than that of the higher-risk group ( P < 0.01). Both PSA and BMI were obviously correlated with the development of high-risk PCa ( P < 0.05), and there was an extreme positive correlation between BMI and Gleason score (r = 0.661 and P = 0.007). It indicated that MOA was established based on conventional MV, which could increase the ultrasonic image quality and calculation speed. Besides, BMI was a risk factor of high-risk PCa and was positively correlated with malignant degree of PCa, which provided a referable evidence for clinical evaluation of malignant degree of PCa.

Volumetric, acoustic and IR spectroscopic properties of binary mixtures (1,2-diaminopropane + methyl-, ethyl-, n-propyl- and n-butyl acetates: A combined experimental and first-principles investigation

Studies of density and speed of sound are commonly used tools to ascertain the properties of pure liquids and the nature of interactions between component molecules of a binary mixture. Herein, the density (ρ) and speed of sound (u) of methyl acetate (MAc), ethyl acetate (EAc), n-propyl acetate (n-PAc) and n-butyl acetate (n-BAc) and their binary mixture with 1,2-diaminopropane (1,2-DAP) were measured over the entire composition range at atmospheric pressure 0.1 MPa and in the temperature range of 298.15–318.15 K with a step of 5 K. Different excess thermo-physical properties including the excess molar volume (VmE), excess ultrasonic speed (uE), excess free volume (VfE), excess intermolecular free length (LfE), and excess molar isentropic compressibility were evaluated from the measured results of ρ and u. The evaluated properties were also analysed in terms of the extent and nature of interactions. The Redlich-Kister polynomial equation was used to correlate the various excess properties to the composition. Further, the u data is analysed by various correlations, Schaaff’s collision factor theory (CFT) and Jacobson’s free length theory (JFLT). The effect of chain length, branching and temperature on the intermolecular interactions and the magnitude of the measured properties have also been systematically analysed. Furthermore, excess molar properties and the intermolecular interactions have been interpreted in the light of Fourier transform infrared spectroscopy (FT-IR) and density functional theory (DFT) studies. Hydrogen-bonded interactions are predicted to play important role in stabilising the binary mixtures.

Engineering properties of factory manufactured paving blocks utilizing steel slag as cement replacement

Vibropressing compaction of dry mixed concrete has increased the production rate of paving blocks, as it eradicated the need of formwork to hold the fresh concrete mixture in shape after molding. This technique also optimized the cost-benefit ratio as it helps in achieving high strength blocks with the minimum utilization of water and cement. In this study, effect of steel slag powder (SSP) was studied as the cement replacement material on the physical and mechanical properties of paving blocks. The cement was replaced with SSP as 5%, 10%, 15%, 20%, 25% and 30% by mass. Incorporation of SSP improved the finishing of paving blocks. The results of compression testing revealed that paving blocks incorporating 5–15% SSP as the cement replacement showed higher strength than the control paving block. This improvement is entirely credited to the better packing of constituent particles caused by the filling effect of SSP. The increase in ultrasonic pulse speed also confirmed that 5–15% SSP improved the density of paving blocks. However, the impact toughness of paving blocks reduced with the rise in SSP percentage beyond 5%.

Density and speed of sound in refrigerant vapor R-125 (31 wt. %) + R-134A (69 wt. %)

Using a constant volume piezometer and ultrasonic interferometer methods, the density and speed of sound in gaseous mixture R-125 (31 wt. %) + R-134a (69 wt. %) were measured within the temperature range from 293 to 393 K and at pressure from 0.18…0.47 to 2.5 MPa. The errors in the measuring temperature, pressure, density and speed of sound were ±20 mK, ±4 kPa, ± (0.15–0.3) %, ± (0.1–0.2) %, respectively. It was shown that the speed of sound values increase with temperature and decrease with pressure. The obtained results were compared with the calculations using the REFPROP software.

Ultrasonic characterization of cold sintered ZnO components with varying relative densities

The cold sintering process is a low temperature processing technique used to synthesize metals, ceramics, and composites. Some cold sintered parts do not reach the mechanical properties of conventionally sintered parts even at high relative densities. These diminished mechanical properties are presumed to be in part a result of either in inhomogeneous removal of transient liquid phases or inability to reach the proper cold sintering temperature/pressure everywhere in the part. In this presentation, we evaluate the spatial variability in the properties of cold sintered ZnO parts with decreasing relative densities through ultrasonic testing. The presence of homogeneously distributed porosity is assessed by ultrasonic wave speed, while macro-flaws larger than the average pore size are assessed through ultrasonic attenuation. The results are compared to the response of conventionally sintered ZnO samples with densities ranging from 86% to 89%. Conventionally sintered and cold sintered parts exhibited different slopes in the decrease of wave speed with density. This difference suggests microstructural discrepancies beyond porosity in cold versus conventionally sintered ZnO components. Attenuation results suggested the presence of macro-flaws even in the samples with highest relative density. These results underscore the importance of nondestructive characterization of the cold sintered components.