Ultrasonic Measurements Research Articles

Reassessment of Birch's Law on hcp‐Fe From Ultrasonic Sound Velocity Measurement and Implications on the Velocity Profiles of Earth's Inner Core

AbstractWe performed in situ X‐ray diffraction and ultrasonic sound velocity measurements on hcp‐Fe up to 15 GPa, 873 K in a multi‐anvil apparatus. The elastic moduli and their pressure and temperature derivatives were determined by fitting the velocity and density data to the third‐order finite strain equations, yielding KS0 = 169.0(57) GPa, KS0′ = 5.4(6), (∂KS/∂T)P = −0.031(3) GPa/K, G0 = 104.5(27) GPa, G0′ = 1.7(2), (∂G/∂T)P = −0.060(2) GPa/K. Within the experimental P‐T range, we find significant temperature effect on the density‐velocity (ρ − VP or S) relations and caution the use of the temperature‐independent Birch's law for extrapolation to core conditions. Furthermore, temperature‐induced velocity decrease is more significant in VS than in VP, offering a possible explanation for the high Poisson's ratio in the core. Extrapolations based on our results together with previous experimental data suggest that VP of hcp‐Fe aligns with PREM at Earth's core conditions, while Vs and density are approximately 10% and 2.7% higher than PREM, respectively.

Functional and morphological evaluation of the dentofacial system in patients with distal occlusion using ultrasonic diagnostic methods

Relevance. The integrity of the dentofacial system, significantly influenced by the functional condition of the masseter muscles (MM) and the morphological alterations in the alveolar bone, plays a crucial role in the outcome and duration of orthodontic treatment for distal occlusion. Ultrasonic diagnostic methods, due to their physiological compatibility, high information content, and ergonomic design, offer a preferable alternative for assessing and tracking these changes throughout orthodontic treatment.Materials and methods. This study included 55 individuals of both genders, aged 9-12, with either normal occlusions (NO) or distal occlusions (DO). Ultrasound examinations of the MM at rest and during maximum voluntary teeth clenching were conducted to evaluate MM thickness and echotexture. Ultrasonic densitometry measurements were conducted through the assessment of ultrasound transit velocity (UTV). This was carried out across the interalveolar bone with probes positioned on the buccal and oral sides between two neighboring teeth roots.Results. The findings indicated that DO patients had a notably thicker MM compared to their NO counterparts. Variations in MM echotexture were observed, with differences in the anechogenic and hyper echogenic zones. Recorded UTV values illustrated that the highest alveolar bone density in DO subjects was predominantly in the frontal regions of both jaws on the left side, whereas the lowest density was observed in the right lateral regions. For NO subjects, the highest density values were identified in the frontal region of the mandibular bone, with the lowest in the maxillary bone's lateral regions on both sides.Conclusion. The application of advanced ultrasonic diagnostic methods in this study facilitated a detailed functional and morphological analysis of the MM, as well as an evaluation of alveolar bone density in individuals with both distal and normal occlusions. The development of ultrasonic alveolar bone density chart from this research provides a valuable addition to dental examination protocols for patients undergoing orthodontic treatment.

Experimental Analysis of Pre-Forming Parameters on Abnormalities, Thickness, and Void Content of Glass/Epoxy Composite In VBO-Oven Cure Manufacturing

Autoclave-based production of composite laminates leads to extended time requirements, increased manufacturing expenses, and the accumulation of significant residual stress. These limitations have spurred research and innovation in seeking alternative out-of-autoclave (OOA) processing methods. The present study aimed to measure the impact of distinct and combined pre-forming parameters within the pre-forming process of vacuum bagging with oven curing (VBO-oven curing) on thickness, abnormalities, and void content in cured laminates of conventional, cost-effective glass/epoxy autoclave composite material. The abnormalities were analyzed using ultrasonic C-scan and thickness measurement was done to determine thickness variations. A burn-off test was employed to measure the void content. The relationship between processing parameters was subsequently investigated via analysis of variance (ANOVA). Higher thickness standard deviation was yielded at higher abnormality percentages in the C-scan results, resembling total discontinuities and non-uniformities. Voids were highest in the laminate produced via the standard pre-forming process. Edge breather, release wax, and intensifier reduced the void content by approximately 11.87%, 12.93% and 6.85%, respectively.

Imaging of annulus-formation interface using reverse time migration based on ultrasonic pitch-catch measurements: Case studies from an experimental well and a field well

Cased-hole logging using ultrasonic pitch-catch modality is a proven technique for cement bond evaluation in cased holes. However, complex measuring environments such as tool and casing eccentering makes it difficult to precisely separate and pick the third interface echoes from full ultrasonic Lamb waves, leading to ambiguous identification of annulus-formation interface. To overcome this problem, we propose an improved cased-hole reverse time migration approach for ultrasonic pitch-catch measurements to image the annulus-formation interface. The missing ultrasonic Lamb waveforms between far and near receivers due to insufficient spatial sampling are reconstructed based on the optimized theoretical phase velocity of zero-order anti-symmetric Lamb mode waves. Additionally, we apply the hybrid illumination imaging condition to mitigate the imaging noises around the true reflectors and sources. Data examples from a physical experimental well and a field well demonstrate that the proposed approach is an effective method for characterizing the annulus-formation interface without requiring precise knowledge of the velocity distribution in the region behind the casing. Furthermore, test on an experimental well has indicated that the method has the potential to detect the absence of cement in the annulus medium.

Simulation of Shear and Tensile Fractures Using Ductile Phase Field Modelling with the Calibration of P Wave Velocity Measurement and Moment Tensor Inversion

The appropriate understanding and formulation of rock discontinuities via FEM is still challenging for rock engineering, as continuous algorithms cannot handle the discontinuities in rock mass. Also, different failure modes of rock samples, containing tensile and shear failure, need to be computed separately. In this study, a novel double-phase field damage model was introduced with two independent phase field damage variables. The construction of the proposed model follows the thermodynamics framework from the overall Helmholtz free energy, with elastic, plastic and surface damage components. The proposed model is calibrated via traditional damage variables, based on ultrasonic wave velocity measurement and acoustic emission monitoring, and both show great consistency between simulation results and laboratory observations. Then the double-phase field damage model is applied to COMSOL software to simulate microcrack propagation in a pre-fractured rock sample. Both lateral and wing cracks are observed in this study, manifested as shear- and tensile-dominated cracks. We also observed different microcracking mechanisms in the proposed numerical models, such as tensile and shear cracking, the influence of plastic strain and the percolation between tensile and shear microcracks. Overall, this study provides valuable insights into the mechanics of microcracking in rocks, and the proposed model shows promising results in simulating crack propagation.

Effects of B2 ordered structure on the mechanical properties of TiZrHfCoNiCu high-entropy alloy

High-entropy alloys (HEAs) were once considered to be typical disordered solid solutions with various atoms randomly distributed in a lattice. Recent studies have found that owing to the chemical complexity of multiple primary elements, HEAs may also form ordered structures that directly influence their mechanical properties. In this study, B2-ordered and body-centered-cubic-disordered structures of TiZrHfCoNiCu HEAs were established using the special quasi-random structure method. The results of first principles calculations and ultrasonic wave velocity measurements indicated that the B2-ordered TiZrHfCoNiCu HEA exhibited superior phase stability, structural stability, and mechanical properties such as strength and hardness. Significantly, the results of this study revealed the physical mechanisms underlying the excellent mechanical properties of ordered HEAs and can guide their design and development accordingly.

Experimental and theoretical analysis of finely bedded porous rock models with internal cracks

The behavior of ultrasonic waves in synthetic rocks consisting of alternating layers of sand-based (porous and permeable) and acrylic (unporous) materials is investigated. Two synthetic layered media are created, one without cracks and the other with parallel cracks in one of the layers, to increase anisotropy and simulate a heterogeneous transversely isotropic medium with a vertical axis of symmetry. Microcomputed tomography is used to obtain images of the samples, which indicate that there are no bubbles present and that the layers are well connected without any gaps or breaks. The experiment uses ultrasonic measurements to determine the propagation of P and S waves, with transducers at frequencies of 100 kHz, 500 kHz, and 1 MHz for traveltime and waveform measurements. These three sources are chosen to verify the effective behavior of the samples, which depends on the relationship between the dominant wavelength of investigation and the layer thickness ([Formula: see text]). The measured velocities are compared with theoretical models based on Backus, Kennett (traditional models), and Backus (modified for cracked media by Schoenberg and Muir’s theory). The main finding is that the cracked medium exhibits at least twice as large a difference in behavior for P- and S-wave vertical velocities as a function of the number of layers compared with the uncracked medium.

Real-Time Temperature Monitoring of Lithium Batteries Based on Ultrasonic Technology.

Electrochemical energy storage stations serve as an important means of load regulation, and their proportion has been increasing year by year. The temperature monitoring of lithium batteries necessitates heightened criteria. Ultrasonic thermometry, based on its noncontact measurement characteristics, is an ideal method for monitoring the internal temperature of lithium batteries. In this study, temperature and ultrasonic time delay measurement experiments were conducted on 18650 lithium batteries and laminated and wound lithium batteries to obtain the corresponding relationship between temperature and time delay and validate the temperature measurement for the same type of battery. The experimental results show that (1) the ultrasonic temperature measurement technique exhibits a relatively large error when used for 18650 Li-ion batteries under experimental conditions; (2) in the experiments on laminated and wound soft-pack lithium batteries, the relationship between temperature and time delay exhibits a nonlinear characteristic; and (3) under the experimental conditions, the ultrasonic temperature measurement errors were ±1.1 °C for stacked Li-ion batteries and ±1.4 °C for wound Li-ion batteries.

High fidelity ultrasonic measurements for defect detection and characterisation

Repeatable measurements with detachable transducers such as phased arrays have much potential for enhancing the sensitivity of nondestructive evaluation (NDE), as baseline subtraction can be employed. This paper aims to develop post-processing methods to overcome the variation between inspections which leads to poor subtraction performance. In this paper, ultrasonic immersion inspections are performed on a brass sample and a steel sample with a corroded backwall. Reference measurements are taken, and then small defects are machined to simulate defect growth in industrial applications. Defect types include two 1 mm diameter flat bottom holes (FBH) extending from 15 mm to 17 mm in the brass sample and two 2 mm diameter holes drilled to 1 mm depth from the corroded surface of the steel sample to represent the growth of localised pits. Although FMC/TFM is used in this paper, the defects have similar response amplitudes to the structural noise, and they cannot be detected or characterised directly from the images by the conventional 6 dB drop method. This paper demonstrates the utilisation of ultrasonic measurements, together with cross-correlation, to obtain inspection variables which include array position and couplant wave velocity. By knowing the variations between inspection conditions, compensation is made in post-processing to improve image repeatability, and hence the performance of baseline subtraction. The SNR is improved by approximately 10–25 dB depending on how great the actual variations are. It is shown that these previously undetectable defects can be seen and accurately sized after conducting baseline subtraction with compensation.

High precision ultrasonic measurement method for thin-walled parts

Thin-walled parts are extensively utilized in the aerospace industry, where over thinning defects in these parts would significantly compromise mechanical safety. Ultrasound measurement methods are commonly employed for thickness non-destructive testing. Manual calibration of reference signals is usually necessary, negatively impacting automation, robustness, and accuracy. This paper proposes a high-precision ultrasound amplitude method for thin-walled component inspection, getting rid of manual calibration. Firstly, the measured signal is preprocessed to extract the spectrum in the effective frequency range. Then, the spectrum is approximated using the asymmetrical Gaussian amplitude model to estimate the spectrum of reference signal and reflection coefficient. Moreover, initial propagation time is estimated from autocorrelation of the signal. Finally, the accurate thickness is obtained from the numerical calculation of reflection coefficient with the initial time. Simulations and experiments demonstrate that the proposed method can accurately measures metal plates as thin as 0.5 mm. Compared to the traditional correlation method, it greatly improves measurement accuracy and stability, reducing them to 1/2 and 1/4 of the latter, respectively. Additionally, the proposed method also demonstrates high accuracy for curved thin plates, with an average relative error of only 0.57 %. Furthermore, the method exhibits high levels of automation, robustness, and accuracy, and holds significant potential for thickness detection in thin-walled structural components.

Innovative Approach for Detecting Early-Stage Partial Discharges in Instrument Transformers via Ultrasound and Random Forest Analysis

This article introduces a novel technique for detecting and classifying Partial Discharges in Instrument Transformers, addressing the gradual breakdown of external insulation in high-voltage electrical equipment through ultrasound measurements. The use of hand-held probe-microphones for ultrasonic sensing gains prominence for its versatility and online diagnostic capabilities. The proposed method combines insights into partial discharge types and the pollution level within the equipment, thereby transforming ultrasonic readings into useful information and facilitating informed decision-making. Laboratory tests simulate real-world conditions to which current and voltage transformers of 145 kV and 245 kV are subjected. These tests result in ultrasonic and apparent charge measurements, also known as Phase-Resolved Partial Discharges (PRPD). A random forest model achieves over 92 % accuracy in classifying ultrasonic signals into eight class: normal, light partial discharge, light corona, corona, light superficial, light saline pollution, moderate saline pollution and heavy saline pollution; enhancing the understanding and predictive maintenance of instrument transformers.

Exploring Ultrasonic Velocity and Compressibility Analysis for Various Edible Oils: A Comparative Study

This study presents a comparative analysis of ultrasonic velocity and compressibility properties in a selection of commonly used edible oils, namely mustard oil, olive oil, coconut oil, groundnut oil, and soybean oil. Understanding the acoustic and compressibility characteristics of these oils is of significant interest due to their widespread culinary and industrial applications. Ultrasonic velocity measurements were conducted using a precision ultrasonic velocity analyzer, while compressibility analysis was performed through precise density measurements. Our findings reveal distinct differences in ultrasonic velocity and compressibility among the various oils. This comparative study contributes to our understanding of the acoustical and compressibility characteristics of edible oils, offering potential applications in food processing, quality control, and product development. Additionally, the findings may have implications in the field of biomedical and industrial applications where these oils are utilized.

Highly-accurate and non-invasive flowrate monitoring for miniature pipelines using piezoelectric micromachined ultrasonic transducers

Noninvasive and real-time flowrate measurement for small pipes is crucial in medical diagnostics and aviation hydraulic system health monitoring. However, current bulk PZT-based ultrasonic flowmeters are unsuitable for these scenarios due to their large size, high power consumption, and poor integration with ICs. This paper proposes a highly accurate and universal ultrasonic flowrate measurement technique for pipes with small diameters (≤ 15 mm) using piezoelectric micromachined ultrasonic transducers (PMUTs) by taking advantage of their miniaturized size, low power consumption, and superior integration capability. A clamp-on testing method is proposed for ultrasound transmitting and receiving. The inside liquid flowrate is measured based on the propagation time difference between the upstream and downstream ultrasound waves. To enhance accuracy, a unique PMUTs chip with a center circular element and an outer annular element is developed to improve acoustic pressure. Additionally, the incident angle and working frequency of ultrasound waves are optimized to reduce the interference caused by ultrasound wave superposition at the PMUTs and pipe wall interface. This optimization also improves acoustic energy transmission and response. The flowrate of water in a steel pipe is successfully measured, demonstrating excellent linearity (99.69%) between flowrate and time difference, with a high accuracy of 2%. Furthermore, flowrate testing for pipes with different diameters and pipe wall materials is experimentally demonstrated, showing widespread usability. The developed PMUTs-based flowmeter is versatile and compatible with common pipes, allowing compact integration in tight spaces, making it highly promising for practical applications.

Backscatter measurement of cancellous bone using the ultrasound transit time spectroscopy.

Recently, ultrasound transit time spectroscopy (UTTS) was proposed as a promising method for bone quantitative ultrasound measurement. Studies have showed that UTTS could estimate the bone volume fraction and other trabecular bone structure in ultrasonic through-transmission measurements. The goal of this study was to explore the feasibility of UTTS to be adapted in ultrasonic backscatter measurement and further evaluate the performance of backscattered ultrasound transit time spectrum (BS-UTTS) in the measurement of cancellous bone density and structure. First, taking ultrasonic attenuation into account, the concept of BS-UTTS was verified on ultrasonic backscatter signals simulated from a set of scatterers with different positions and intensities. Then, in vitro backscatter measurements were performed on 26 bovine cancellous bone specimens. After a logarithmic compression of the BS-UTTS, a linear fitting of the log-compressed BS-UTTS versus ultrasonic propagated distance was performed and the slope and intercept of the fitted line for BS-UTTS were determined. The associations between BS-UTTS parameters and cancellous bone features were analyzed using simple linear regression. The results showed that the BS-UTTS could make an accurate deconvolution of the backscatter signal and predict the position and intensity of the simulated scatterers eliminating phase interference, even the simulated backscatter signal was with a relatively low signal-to-noise ratio. With varied positions and intensities of the scatterers, the slope of the fitted line for the log-compressed BS-UTTS versus ultrasonic propagated distance (i.e., slope of BS-UTTS for short) yield a high agreement (r2 = 99.84%-99.96%) with ultrasonic attenuation in simulated backscatter signal. Compared with the high-density cancellous bone, the low-density specimen showed more abundant backscatter impulse response in the BS-UTTS. The slope of BS-UTTS yield a significant correlation with bone mineral density (r = 0.87; p < 0.001), BV/TV (r = 0.87; p < 0.001), and cancellous bone microstructures (r up to 0.87; p < 0.05). The intercept of BS-UTTS was also significantly correlated with bone densities (r = -0.87; p < 0.001) and trabecular structures (|r|=0.43-0.80; p < 0.05). However, the slope of the BS-UTTS underestimated attenuation when measurements were performed experimentally. In addition, a significant non-linear relationship was observed between the measured attenuation and the attenuation estimated by the slope of the BS-UTTS. This study demonstrated that the UTTS method could be adapted to ultrasonic backscatter measurement of cancellous bone. The derived slope and intercept of BS-UTTS could be used in the measurement of bone density and microstructure. The backscattered ultrasound transit time spectroscopy might have potential in the diagnosis of osteoporosis in the clinic.

IJCM_169A: Correlation of sonographic renal dimensions with anthropometric measurements among individuals without renal disorders

Background: Normal kidney dimensions are suggestive of normal kidney function. Degree of kidney function has a positive correlation with ultrasonic renal measurements. Co-morbid conditions affect the renal size. Therefore it becomes necessary to establish normal values of kidney dimensions for the diagnosis, prognosis and also as an early indication of renal diseases in order to prevent them. Objectives: To study the renal dimensions and association with socio- demographic conditions among the outpatient attendees in the study hospital. Methodology: This was a descriptive cross-sectional study done among the attendees of KMC Hospitals, Mangalore. Data extraction sheet included the socio-demographic details, Anthropometric measurements, personal history, history of comorbidities and sonographic dimensions of Kidney and laboratory findings of Renal Function Test. Data was entered and analyzed by using statistical software Statistical Package for Social Sciences (SPSS) Version 29.0. Results: Out of 194 participants, 118(60.8%) were males. The difference between corresponding kidney lengths of males and females is found to be statistically significant. The length and anteroposterior dimension of left kidney is greater than right kidney and the difference is statistically significant. When the kidney lengths and the heights of the individual were correlated a positive correlation was obtained, (0.278) in case of right kidney and (0.245) in case of left kidney. Conclusion: Kidney length had positive correlation with height and BMI. Female kidney length was significantly smaller than the male kidney length. There was significant variation between right and left kidney lengths.

Sensitivity Improvements for Picosecond Ultrasonic Thickness Measurements in Gold and Tungsten Nanoscale Films

Picosecond ultrasonics, as a nondestructive and noncontact method, can be employed for nanoscale metallic film thickness measurements. The sensitivity of the system, which determines the measurement precision and practicability of this technique, is often limited by the weak intensity of the ultrasonic signal. To solve this problem, we investigate the distinct mechanisms involved in picosecond ultrasonic thickness measurement for two types of metals, namely tungsten (W) and gold (Au). For thickness measurement in W films, theory and simulation show that optimizing the pump and probe laser wavelengths, which determine the intensity and shape of the ultrasonic signal, is critical to improving measurement sensitivity, while for Au film measurements, where acoustic-induced beam distortion is dominant, the signal intensity can be optimized by selecting an appropriate aperture size and sample position. The above approaches are validated in experiments. A dual-wavelength pump–probe system is constructed based on a passively mode-locked ytterbium-doped fiber laser. The smoothing method and multipeak Gaussian fitting are employed for the extraction of ultrasonic time-of-flight. Subnanometer measurement precision is achieved in a series of W and Au films with thicknesses of 43–750 nm. This work can be applied to various high-precision, noncontact measurements of metal film thickness in the semiconductor industry.

Unveiling the synergistic effect of Cd doping on structural, optical, mechanical, and γ-ray shielding characteristics of zinc lead silicate glass

Using the traditional melt quenching process, the glass series of xCdO-(5-x) ZnO-35Pb3O4-60SiO2, where x = 1–5 mol%, were created. The X-ray diffraction method was utilized to investigate the non-crystallinity of the glasses that were created. The densities of the fabricated glasses increased from 5.91 to 6.655 g/cm³. Electronegativity (ΔX), bond density (nb), and field strength (F) were calculated. ΔX decreased while nb and F increased with the supply of Cd ions. The optical characteristics Eg, n, αo, εr, χ(3), n2, M, T and more have been investigated. We found that a change in cadmium concentration in the fabricated system influenced all the optical parameters. The mechanical properties, including elastic moduli, have been investigated alongside ultrasonic velocity measurements. The experimental results demonstrated a strong dependence of calculated parameters on increasing CdO concentration. The observation indicates an increase in the elastic moduli with the increasing CdO concentration. Radiation shielding factors were estimated using EpiXS program. μL, HVL, MFP, Zeff, Neff, EBF and EABF for gamma energy between 15 and 15,000 KeV have been investigated. The results indicate that these parameters are affected by the introduction of CdO content into the glass network. The sample ZPSCd5 exhibits the highest radiation shielding parameters among the studied glass samples.

Comprehensive study on structural, elastic and radiation shielding abilities of novel quaternary Bi2O3–TeO2–Li2O–Al2O3 glasses

Novel quaternary glasses with varying compositions of xBi2O3-(75–x)TeO2–20Li2O–5Al2O3 were synthesized using a melt-quenching method to analyze their physical, elastic properties and to evaluate their potential as radiation shielding materials. The X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and ultrasonic measurement were utilized to study those properties. The radiation shielding properties of the glass samples were determined for 0.01–10000 MeV photon energy range by using Phy-X/PSD software. The incorporation of Bi2O3, ranging from 0 mol% to 5 mol%, led to an increase in density which is measured by Archimedes' principle, ascending from 4.68 to 5.06 g/cm3. The longitudinal, bulk, shear, and Young's modulus, displayed a non-linear decline from 63.41 to 61.44 GPa, 33.52 to 33.20 GPa, 22.41 to 21.18 GPa, and 54.99 to 52.39 GPa. Furthermore, the inclusion of Bi2O3 up to x = 5 mol% produce mass attenuation coefficient (MAC) of 14.892 cm2/g at x-ray energy of 40 KeV, surpassing that of commercial RS360 and RS520 radiation shielding glasses by 577% and 323%, respectively. When subjected to gamma ray of 662 KeV the MAC is 0.08 cm2/g which was also accompanied by a reduction in the half-value layer (HVL) to 1.58 cm where it surpassed the concrete by 38% and linear attenuation coefficient (LAC) of 0.38 cm−1. The effective atomic number (Zeff) and effective electron density (Neff) reach maximum value of 59.74 and 7.88 × 1023 electrons/g at 0.02 MeV respectively. These results highlight the suitability of the glass composition with x = 5 mol% as an exceptional choice for employment as to shield against both X-rays and gamma rays.

Spatiotemporal analysis of the effects of exercise on the hemodynamics of the aorta in hypertensive rats using fluid-structure interaction simulation

Abstract Background and Objective Hemodynamic changes that lead to increased blood pressure represent the main drivers of organ damage in hypertension. Prolonged increases to blood pressure can lead to vascular remodeling, which also affects vascular hemodynamics during the pathogenesis of hypertension. Exercise is beneficial for relieving hypertension, however the mechanistic link between exercise training and how it influences hemodynamics in the context of hypertension is not well understood. Methods n exercise model was developed using spontaneously hypertensive rats (SHR) subject to a 12-week treadmill training regime. The heart rates and blood pressures of rats were measured using the tail cuff method, while micro-computed tomography (CT) scanning was used to develop three-dimensional structures of rat aorta, and ultrasound was used to detect rat aortic blood flow and changes to vessel wall structures. Computational fluid dynamics (CFD) and fluid-structure interaction (FSI) models were used to simulate and measure hemodynamic parameters of the rat aortic vessels. In parallel, Masson staining was performed on fixed samples of blood vessels to investigate collagen volume fraction. Hypertensive rats in the sedentary and long-term exercise training groups were subjected to a single bout exercise training, and their aortic hemodynamic parameters were analyzed before, 5 min, 24 h, and 72 h after the single bout exercise. Results Of the two models, in comparison to actual ultrasonic measurement values recorded, we found that numerical simulation results from the FSI model could more accurately model blood flow in the ascending aorta of hypertensive rats, compared to the CFD model. Moreover, longterm exercise training improved local hemodynamic parameters of blood vessels, and led to improvements in adverse hemodynamic features documented, including time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT). Longterm exercise training of SHR also improved local vascular collagen deposition in the aorta, while improvements in vascular remodeling were also correlated with favorable hemodynamic parameters. Compared with sedentary SHR, signals for low TAWSS regions of the aortic arch in SHR on the long-term exercise regime shifted to the position of the ascending aorta after a single bout of exercise. Conclusions This study demonstrates that FSI is informative to study the spatiotemporal effects of long-term exercise training on hemodynamic changes within the aortas of hypertensive rats, and that long-term exercise is beneficial through its effects to modulate vascular hemodynamics in hypertension.

Non-Kramers doublet ground state in a quaternary cubic compound PrRu2In2Zn18 investigated by ultrasonic measurements

Abstract We performed ultrasonic measurements on a quaternary cubic compound PrRu2In2Zn18 to explore the ground state properties derived from non-Kramers Γ3 doublet of Pr3+. PrRu2In2Zn18 is a quaternary derivative of the ternary compound PrRu2Zn20 that exhibits a structural phase transition at T S = 138 K. In PrRu2In2Zn18, the Zn atoms at the 16c site in PrRu2Zn20 are selectively replaced by In atoms. A monotonic increase was observed in the temperature dependence of elastic constants C L = (C 11 + 2C 12 + 4C 44)/3 and C T = (C 11–C 12 + C 44)/3 in the temperature range around T S to which an elastic softening was observed in (C 11 – C 12)/2 for PrRu2Zn20. The disappearance of the softening indicates that the structural transition in PrRu2Zn20 is suppressed by the substitution of Zn ions by In ones with a larger ionic radius. Alternatively, the C T of PrRu2In2Zn18 exhibits a precursor Curie-type elastic softening toward low temperatures being responsible for the non-Kramers Γ3 ground state. We discuss the ground state and the evolution of the elastic properties of the different single-crystal samples of PrRu2In2Zn18 grown under different conditions.