A Novel On-Site-Real-Time Method for Identifying Characteristic Parameters Using Ultrasonic Echo Groups and Neural Network

On-site and real-time non-destructive measurement of elastic constants for materials of a component in a in-service structure is a challenge due to structural complexities,such as ambiguous boundary,variable thickness,nonuniform material properties.This work develops for the first time a method that uses ultrasound echo groups and artificial neural network(ANN)for reliable on-site real-time identification of material parameters.The use of echo groups allows the use of lower frequencies,and hence more accommodative to structural complexity.To train the ANNs,a numerical model is established that is capable of computing the waveform of ultrasonic echo groups for any given set of material properties of a given structure.The waveform of an ultrasonic echo groups at an interest location on the surface the structure with material parameters varying in a predefined range are then computed using the numerical model.This results in a set of dataset for training the ANN model.Once the ANN is trained,the material parameters can be identified simultaneously using the actual measured echo waveform as input to the ANN.Intensive tests have been conducted both numerically and experimentally to evaluate the effectiveness and accuracy of the currently proposed method.The results show that the maximum identification error of numerical example is less than 2%,and the maximum identification error of experimental test is less than 7%.Compared with currently prevailing methods and equipment,the proposefy the density and thickness,in addition to the elastic constants.Moreover,the reliability and accuracy of inverse prediction is significantly improved.Thus,it has broad applications and enables real-time field measurements,which has not been fulfilled by any other available methods or equipment.

Metallographic structure,mechanical properties,and process parameter optimization of 5A06 joints formed by ultrasonic-assisted refill friction stir spot welding

Novel hybrid refill friction stir spot welding （RFSSW） assisted with ultrasonic oscillation was introduced to 5A06 aluminum alloy joints. The metallographic structure and mechanical properties of 5A06 aluminum alloy RFSSW joints formed without ultrasonic assistance and with lateral and longitudinal ultrasonic assistance were compared, and the ultrasonic-assisted RFSSW process parameters were opti- mized. The results show that compared with lateral ultrasonic oscillation, longitudinal ultrasonic oscillation strengthens the horizontal bond- ing ligament in the joint and has a stronger effect on the joint＇s shear strength. By contrast, lateral ultrasonic oscillation strengthens the ver- tical bonding ligament and is more effective in increasing the joint＇s tensile strength. The maximum shear strength of ultrasonic-assisted RFSSW 5A06 aluminum alloy joints is as high as 8761 N, and the maximum tensile strength is 3679 N when the joints are formed at a tool rotating speed of 2000 r/rain, a welding time of 3.5 s, a penetration depth of 0.2 mm, and an axial pressure of 11 kN.

Hysteresis in the ultrasonic parameters of saturated sandstone during freezing and thawing and correlations with unfrozen water content

Determining the mechanical properties of frozen rock is highly important in cold-area engineering.These properties are essentially correlated with the content of liquid water remaining in frozen rock.Therefore,accurate determination of unfrozen water content could allow rapid evaluation of mechanical properties of frozen rock.This paper investigates the hysteresis characteristics of ultrasonic waves applied to sandstone(in terms of the parameters of P-wave velocity,amplitude,dominant frequency and quality factor Q)and their relationships with unfrozen water content during the freeze-thaw process.Their correlations are analysed in terms of their potential for use as indicators of freezing state and unfrozen water content.The results show that:(1)During a freeze-thaw cycle,the ultrasonic parameters and unfrozen water content of sandstone have significant hysteresis with changes in temperature.(2)There are three clear stages of change during freezing:supercooled stage(0℃to-2℃),rapid freezing stage(-2℃to-3℃),and stable freezing stage(-3℃to-20℃).The changes in unfrozen water content and ultrasonic parameters with freezing temperature are inverse.(3)During a single freeze-thaw cycle,the ultrasonic parameters of sandstone are significantly correlated with its unfrozen water content,and this correlation is affected by the pore structure.For sandstones with mesopores greater than 50%,there are inflection points in the curves of ultrasonic parameters vs.unfrozen water content at-3℃during freezing and at-1℃during thawing.It was found that thermal deformation of the mineral-grain skeleton and variations in the phase composition of pore water change the propagation path of ultrasonic waves.The inflection point in the curve of dominant frequency vs.temperature clearly marks the end of the rapid freezing stage of pore water,in which more than 70%of the pore water freezes.Consequently,the dominant frequency can be used as an index to conveniently estimate the unfrozen water content of frozen rock and,hence,its mechanical properties.

Determination of the parameters of a linear-viscoelastic thin layer using the normally-incident ultrasonic waves

This paper proposes a method of simultaneous determination of the four layer parameters （mass density, longitudinal velocity, the thickness and attenuation） of an immersed linear-viscoelastic thin layer by using the normally-incident reflected and transmitted ultrasonic waves. The analytical formula of the layer thickness related to the measured trans- mitted transfer functions is derived. The two determination steps of the four layer parameters are developed, in which acoustic impedance, time-of-flight and attenuation are first determined by the reflected transfer functions. Using the derived formula, it successively calculates and determines the layer thickness, longitudinal velocity and mass density by the measured transmitted transfer functions. According to the two determination steps, a more feasible and simplified measurement setups is described. It is found that only three signals （the reference waves, the reflected and transmitted waves） need to be recorded in the whole measurement for the determination of the four layer parameters. A study of the stability of the determination method against the experimental noises and the error analysis of the four layer parameters are made. This study lays the theoretical foundation of the practical measurement of a linear-viscoelastic thin layer.

Temperature and Orientation Dependence of Ultrasonic Parameters in Americium Monopnictides

The temperature dependence of the ultrasonic parameters like ultrasonic velocities and Grüneisen parameters in americium monopnictides AmY (Y: N, P, As, Sb and Bi) have been studied for longitudinal and shear waves along , and crystallographic directions in the temperature range 100 K - 500 K. The second- and third- order elastic constants have also been evaluated for these monopnictides using Coulomb and Born-Mayer potential. The values of elastic constants are the highest for AmN. Hence the mechanical properties of AmN are better than other monopnictides AmP, AmAs, AmSb and AmBi. Ultrasonic velocity is found large for AmP. So the ultrasonic wave propagation will be much better than others in AmP. Obtained results are compared with available results of same type of materials.

Relationship of ultrasonic elastography parameters of cervical cancer with the cancer cell growth and angiogenesis in the lesion tissue

Objective: To study the relationship of ultrasonic elastography parameters of cervical cancer with the cancer cell growth and angiogenesis in the lesion tissue. Methods: A total of 110 patients who were diagnosed with cervical cancer in the hospital between December 2015 and January 2017 were collected as the observation group, 80 patients who received hysteroscopic cervical polyp resection in the hospital during the same period were collected as the control group. The levels of cervical ultrasonic elastography parameters in the two groups were detected, and fluorescence quantitative PCR was used to determine the expression of proliferation genes, apoptosis genes and angiogenesis-related genes in the lesion tissue. Pearson test was used to evaluate the correlation between cervical ultrasonic elastography parameters and the tumor malignancy indexes. Results: Elastic image press release index and strain ratio of local lesion of observation group were significantly higher than those of control group;GBP1 mRNA expression in lesion tissue of observation group was lower than that in lesion tissue of control group while Prdx4, STAT3 and Sp2 mRNA expression were higher than those in lesion tissue of control group;Survivin, FasL and Bcl-2 mRNA expression in lesion tissue of observation group were higher than those in lesion tissue of control group while Fas and Bax mRNA expression were lower than those in lesion tissue of control group;VEGF, MMP-9, COX-2 and HIF-1 mRNA in lesion tissue of observation group were significantly higher than those in lesion tissue of control group. Conclusion: Elastic image press release index and strain ratio of cervical tissue of patients with cervical cancer are higher, and the specific increase is directly correlated with the tumor malignancy.

Change of left ventricular ultrasonic functional parameters in patients with ACS during peri-PCI period and their relationship with degree of serum myocardial damage

Objective:To study the change of left ventricular ultrasonic functional parameters in patients with ACS during peri-PCI period and their relationship with degree of serum myocardial damage.Methods:A total of 76 cases of ACS patients who were treated in our hospital between June 2012 and January 2016 were selected as research subjects, treatment methods were reviewed and then all patients were divided into observation group (n=57) who underwent PCI treatment and control group (n=19) who conformed to PCI indications but underwent conservative treatment under patients' or families' insistence. Left ventricular ultrasonic functional parameter levels and serum myocardial injury index contents were compared between two groups of patients before and after treatment. Pearson test was used to evaluate the relationship between left ventricular ultrasonic functional parameters and myocardial injury in patients with ACS.Results: Before treatment, differences in left ventricular ultrasonic functional parameter levels as well as serum contents of myocardial enzyme spectrum and myocardial apoptosis indexes were not statistically significant between the two groups of patients. After treatment, left ventricular ultrasonic functional parameters LVEDD and LVESD levels in observation group were lower than those in control group while SV level was higher than that in control group;serum contents of myocardial enzyme spectrum cTnT, LDH, CK-MB and AST were lower than those in control group;serum contents of myocardial apoptosis indexes Fas, Caspase-3 and caspase-12 were lower than those in control group while Bcl-2 content was higher than that in control group. The left ventricular ultrasonic functional parameters in ACS patients were directly correlated with the degree of myocardial injury.Conclusion: PCI treatment of patients with ACS can significantly improve left ventricular function and reduce myocardial injury. After treatment, the left ventricular ultrasonic functional parameters are directly correlated with the degree of myocardial injury.

Effect of Curing Age on Tensile Properties of Fly Ash Based Engineered Geopolymer Composites(FA-EGC)by Uniaxial Tensile Test and Ultrasonic Pulse Velocity Method

Tensile properties of fly ash based engineered geopolymer composites(FA-EGC)at different curing ages were studied by uniaxial tensile test and ultrasonic pulse velocity(UPV)methods,which included uniaxial tensile properties,the correlation between ultrasonic pulse velocity and tensile properties,and characteristic parameters of microcracks.The experimental results show that obvious strain hardening behavior can be found in FA-EGC at different curing ages.With the increase of curing age,the tensile strength increases,the tensile strain decreases and the toughness becomes worse.The UPV of FA-EGC increases with curing age,and a strong correlation can be found between tensile strength and UPV.With the increase of curing age,the average crack width of FA-EGC decreases and the total number of cracks increases.This is because the strength of geopolymer increases fast at early age,thus the later strength development of FA-EGC tend to be stable.At the same time,the bond strength between fiber and matrix,and the friction of fiber/matrix interface continue to increase with curing age,thus the bridging effect of fiber is gradually strengthened.In conclusion,the increase of curing age is beneficial to the development of tensile properties of FA-EGC.

THE APPLICATION OF GENETIC ALGORITHM IN NON-LINEAR INVERSION OF ROCK MECHANICS PARAMETERS

The non-linear inversion of rock mechanics parameters based on genetic algorithm is presented. The principIe and step of genetic algorithm is also given. A brief discussion of this method and an application example is presented at the end of this paper. From the satisfied result, quick, convenient and practical new approach is developed to solve this kind of problems.

An experimental study on the relationship between acoustic parameters and mechanical properties of frozen silty clay

To study the influence of temperature and water content on ultrasonic wave velocity and to establish the relationship between ultrasonic wave velocity and frozen silty clay strength, ultrasonic tests were conducted to frozen silty clay by using RSM-SY5（T） nonmetal supersonic test meter, and the tensile strength and compressive strength of silty clay were measured under various negative temperatures. Test and analysis results indicate that, ultrasonic wave velocity rapidly changes in the temperature range of-1 ℃ to -5 ℃. Ultrasonic wave velocity increased with an increase of water content until the water content reached the critical water content, while decreased with an increase of water content after the water content exceeded the critical water content. This study showed that there was strong positive correlation between the ul- trasonic wave velocity and the frozen soil strength. As ultrasonic wave velocity increased, either tensile strength or com- pressive strength increased. Based on the experimental data, the relationship between ultrasonic wave velocity and frozen silty clay strength was obtained through regression analysis. It was found that the ultrasonic test technique can be used to test frozen soils and lay the foundation for the determination of frozen soil strength.

Effects of Ultrasonic Treatment on Residue Properties

The changes in properties and structural parameters of four vacuum residue samples before and after ultrasonic treatment were analyzed. Ultrasonic treatment could increase the carbon residue value, decrease the average molecular weight and viscosity, which can barely inlfuence the density of vacuum residue. Meanwhile the constitution of residue can be varied including the decrease in the content of saturates, aromatics and asphaltenes, while the increase in the content of resins can lead to an increase in the total content of asphaltenes and resins. Among the four kinds of residue samples, there is a common trend that the more the content of asphaltenes in feedstock is, the more the increase in the content of resins, the more signiifcant decrease in the aromatic content and the less decrease in the saturates content after ultrasonic treatment of residue would be. Changes in the structure and content of asphaltenes caused by ultrasonic treatment have a signiifcant impact on the changes in residue properties. Ultrasonic treatment has changed the structural parameters of residue such as decrease in the total carbon number of average molecule （CTotal）, the total number of rings （RT）, the aromatic carbon number （CA）,the aromatic rings number （RA） and the naphthenic rings number （RN） , and increase of characterization factor （KH）. The study has indicated that ultrasonic treatment of vacuum residue can change the average structure of residue, and the changes in the content and structure of asphaltenes are the main cause leading to property changes. The results of residue hydrotreat-ing revealed that coke yield decreased, whereas the gas and light oil yield and conversion increased after ultrasonic treat-ment of vacuum residue.

Experimental Study of Parameters of a Plasma Antenna

A plasma column excited by a surface wave can act as a plasma antenna. Experiments are carried out to study the current and conductivity distributions, field, power patterns, directivity and efficiency of such a plasma antenna. In addition, an equivalent metallic copper antenna is built up and its antenna parameters are compared with that of the plasma antenna. Our findings indicate that the power content in the harmonics of the plasma antenna is more prominent as compared to the copper antenna （which only generates a fundamental frequency）. However, the power patterns for both antennae are quite similar. To provide a more qualitative understanding regarding the generation of harmonics in the field of the plasma antenna, a bi-spectral analysis is performed to study the nonlinear interactions in the current fluctuations. Some specific features of the plasma antenna are investigated in our study, which may enhance the application prospect of the plasma antenna with respect to the conventional metallic antenna.

Study on Collision Between Two Ships Using Selected Parameters in Collision Simulation

In the present analysis, several parameters used in a numerical simulation are investigated in an integrated study to obtain their influence on the process and results of this simulation. The parameters studied are element formulation, friction coefficient, and material model. Numerical simulations using the non-linear finite element method are conducted to produce virtual experimental data for several collision scenarios. Pattern and size damages caused by collision in a real accident case are assumed as real experimental data, and these are used to validate the method. The element model study performed indicates that the Belytschko-Tsay element formulation should be recommended for use in virtual experiments. It is recommended that the real value of the friction coefficient for materials involved is applied in simulations. For the study of the material model, the application of materials with high yield strength is recommended for use in the side hull structure.

Ultrasonic study on organic liquid and binary organic liquid mixtures by using Schaaffs＇ collision factor theory

Based on Schaaff＇s collision factor theory （CFT） in liquids, the equations for nonlinear ultrasonic parameters in both organic liquid and binary organic liquid mixtures are deduced. The nonlinear ultrasonic parameters, including pressure coefficient, temperature coefficients of ultrasonic velocity, and nonlinear acoustic parameter B/A in both organic liquid and binary organic liquid mixtures, are evaluated for comparison with the measured results and data from other sources. The equations show that the coefficient of ultrasonic velocity and nonlinear acoustic parameter B/A are closely related to molecular interactions. These nonlinear ultrasonic parameters reflect some information of internal structure and outside status of the medium or mixtures. From the exponent of repulsive forces of the molecules, several thermodynamic parameters, pressure and temperature of the medium, the nonlinear ultrasonic parameters and ultrasonic nature of the medium can be evaluated. When evaluating and studying nonlinear acoustic parameter B/A of binary organic liquid mixtures, there is no need to know the nonlinear acoustic parameter B/A of the components. Obviously, the equation reveals the connection between the nonlinear ultrasonic nature and internal structure and outside status of the mixtures more directly and distinctly than traditional mixture law for B/A, e.g. Apfel＇s and Sehgal＇s laws for liquid binary mixtures.

Experimental verification of parameter m in Hoeke-Brown failure criterion considering the effects of natural fractures

HoekeBrown failure criterion is one of the widely used rock strength criteria in rock mechanics and mining engineering.Based on the theoretical expression of HoekeBrown parameter m of an intact rock,the parameter m has been modified by crack parameters for fractured rocks.In this paper,the theoretical value range and theoretical expression form of the parameter m in HoekeBrown failure criterion were discussed.A critical crack parameter B was defined to describe the influence of the critical crack when the stress was at the peak,while a parameter b was introduced to represent the distribution of the average initial fractures.The parameter m of a fractured rock contained the influences of critical crack(B),confining pressure(s3)and initial fractures(b).Then the triaxial test on naturally fractured limestones was conducted to verify the modification of the parameter m.From the ultrasonic test and loading test results of limestones,the parameter m can be obtained,which indicated that the confining pressure at a high level reduced the differences of m among all the specimens.The confining pressure s3 had an exponential impact on m,while the critical crack parameter B had a negative correlation with m.Then the expression of m for a naturally fractured limestone was also proposed.

Detection of Cracks in Aerospace Turbine Disks Using an Ultrasonic Phased Array C-scan Device

Crack detection in an aerospace turbine disk is essential for aircraft-quality detection.With the unique circular stepped structure and superalloy material properties of aerospace turbine disk,it is difficult for the traditional ultrasonic testing method to perform efficient and accurate testing.In this study,ultrasound phased array detection technology was applied to the non-destructive testing of aviation turbine disks:(i)A phased array ultrasonic c-scan device for detecting aerospace turbine disk cracks(PAUDA)was developed which consists of phased array ultrasonic,transducers,a computer,a displacement encoder,and a rotating scanner;(ii)The influence of the detection parameters include frequency,wave-type,and elements number of the ultrasonic phased array probe on the detection results on the near-surface and the far surface of the aerospace turbine disk is analyzed;(iii)Specimens with flat-bottom-hole(FBH)defects were scanned by the developed PAUDA and the results were analyzed and compared with the conventional single probe ultrasonic water immersion testing.The experiment shows that by using the ultrasonic phased array c-scan to scan the turbine disk the accuracy of the detection can be significantly improved which is of greater accuracy and higher efficiency than traditional immersion testing.

Ultrasonic Wave Propagation in Californium Monopnictides

In this paper, we have investigated the temperature dependence of the ultrasonic parameters like ultrasonic velocities and Grüneisen parameters in californium monopnictides CfY (Y: N, As and Sb) for longitudinal and shear waves along , and crystallographic directions in the temperature range 100–500K. For the same evaluation the second- and third- order elastic constants have also been computed for these monopnictides using Coulomb and Born-Mayer potential upto second nearest neighborhood. The mechanical properties and stability of CfN is best, because of its high valued elastic constants. Ultrasonic velocity is found to be highest for CfAs along all chosen directions, so CfAs will be most suitable compound for wave propagation. The obtained results of present investigation are discussed in along with identified thermophysical properties.

An Evolutionary Firefly Algorithm, Goal Programming Optimization Approach for Setting the Osmotic Dehydration Parameters of Papaya

An evolutionary nature-inspired Firefly Algorithm (FA) is employed to set the optimal osmotic dehydration parameters in a case study of papaya. In the case, the functional form of the dehydration model is established via a response surface technique with the resulting optimization formulation being a non-linear goal programming model. For optimization, a computationally efficient, FA-driven method is employed and the resulting solution is shown to be superior to those from previous approaches for determining the osmotic process parameters. The final component of this study provides a computational experimentation performed on the FA to illustrate the relative sensitivity of this evolutionary metaheuristic approach over a range of the two key parameters that most influence its running time-the number of iterations and the number of fireflies. This sensitivity analysis revealed that for intermediate-to-high values of either of these two key parameters, the FA would always determine overall optimal solutions, while lower values of either parameter would generate greater variability in solution quality. Since the running time complexity of the FA is polynomial in the number of fireflies but linear in the number of iterations, this experimentation shows that it is more computationally practical to run the FA using a “reasonably small” number of fireflies together with a relatively larger number of iterations than the converse.

Solvation number, thermochemical parameter, and viscosity study of sweeteners in aqueous and non-aqueous media through ultrasonic measurements

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℃.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.

超声参数与瘢痕妊娠分型的关联性及诊断价值研究

目的 探讨超声参数与瘢痕妊娠分型的关联性及诊断价值。方法 选取2021年10月~2022年12月河北省衡水市第二人民医院73例CSP患者设为研究组,另选取同期正常妊娠女性73例设为对照组。两组受检者均接受TVS检查,统计研究组与对照组、研究组不同CSP分型患者超声检查参数[瘢痕肌层厚度(CSM)、子宫下段前壁血流阻力指数(RI)、最小矢状肌厚度],分析超声检查参数与CSP分型的关联性,并比较各参数对CSP的单独及联合诊断效能。结果 研究组CSM、RI、最小矢状肌厚度低于对照组(P<0.05)。不同CSP患者CSM、RI、最小矢状肌厚度间存在显著差异(P<0.05);多重比较,Ⅱ型CSP患者CSM、RI、最小矢状肌厚度低于Ⅰ型CSP患者,Ⅲ型CSP患者CSM、RI、最小矢状肌厚度低于Ⅱ型CSP患者(P<0.05)。CSM、RI、最小矢状肌厚度与CSP疾病分型存在显著负相关关系(P<0.05)。CSM、RI及最小矢状肌厚度联合诊断CSP的AUC为0.719%,大于CSM、RI及最小矢状肌厚度单独诊断的0.706、0.660、0.625。结论 CSP经超声检查可见明显异常,不同CSP分型患者各检查参数存在显著差异,两者具有紧密相关性,临床可通过超声检查对疾病进行诊断评估。