Ultrasonic Speed Measurements Research Articles

Calibration and validation of the foundation for a multiphase strength model for tin

In this work, the Common Model of Multi-phase Strength and Equation of State (CMMP) model was applied to tin. Specifically, calibrations of the strength-specific elements of the CMMP foundation were developed with a combination of experiments and theory, and then the model was validated experimentally. The first element of the foundation is a multi-phase analytic treatment of the melt temperature and the shear modulus for the solid phases. These models were parameterized for each phase based on ab initio calculations using the software VASP (Vienna Ab initio Simulations Package) based on density functional theory. The shear modulus model for the ambient β phase was validated with ultrasonic sound speed measurements as a function of pressure and temperature. The second element of the foundation is a viscoplastic strength model for the β phase, upon which strength for inaccessible higher-pressure phases can be scaled as necessary. The stress–strain response of tin was measured at strain rates of 10−3 to 3×103s−1 and temperatures ranging from 87 to 373 K. The Preston–Tonks–Wallace (PTW) strength model was fit to that data using Bayesian model calibration. For validation, six forward and two reverse Taylor impact experiments were performed at different velocities to measure large plastic deformation of tin at strain rates up to 105s−1. The PTW model accurately predicted the deformed shapes of the cylinders, with modest discrepancies attributed to the inability of PTW to capture the effects of twinning and dynamic recrystallization. Some material in the simulations of higher velocity Taylor cylinders reached the melting temperature, thus testing the multiphase model because of the presence of a second phase, the liquid. In simulations using a traditional modeling approach, the abrupt reduction of strength upon melt resulted in poor predictions of the deformed shape and non-physical temperatures. With CMMP, the most deformed material points evolved gradually to a mixed solid–liquid but never a fully liquid state, never fully lost strength, stayed at the melt temperature as the latent heat of fusion was absorbed, and predicted the deformed shape well.

Volumetric, transport and acoustic properties of binary mixtures containing alkanol at 298.15–318.15 K

The measurement of density (ρ), viscosity (η) and ultrasonic speed (u) have been conducted at T = 298.15 K–318.15 K and at 0.1 MPa to study the intermolecular interactions between p–chlorotoluene with alkanol (C1–C2). These data were utilized to derive the excess properties like excess molar volume (VmE), deviation in viscosity (Δη), excess free energy of activation (ΔG*E), deviation in ultrasonic speed (Δu), and excess isentropic compressibility (κsE) for binary mixtures. Utilizing the VmE values, partial molar volume and excess partial molar volume were calculated. The Δη and κsE were investigated using theoretical models such as the Singh model and ab initio approach, which yielded interactional parameters that not only indicate the extent of unlike interactions and depolymerization of self–associated alkanol but also predicts the Δη and κsE for these systems. The conclusions of the ab initio approach were further validated by the Singh model for viscosity. The u data were further interpreted by various correlations and theories. Regarding correlation, Nomoto’s correlation demonstrated high predictive power for ultrasonic speed data, respectively, compared to other correlations. The resulting excess properties were fitted to Redlich–Kister polynomial equations. The VmE values were observed to be negative for p–chlorotoluene + alkanol systems at all temperatures. The study of the binary mixtures is significant because it sheds light on the nature of intermolecular interactions which has practical implications in areas such as chemical synthesis, solvent selection, and understanding the effects of solvents on reaction rates and product yields.

Design of Miniature Clamp-On Ultrasonic Flow Measurement Transducers

Clamp-on ultrasonic transit-time difference measurements of liquid flowrate are widely used in industry for both flow metering and heat metering applications. However, the sensors used tend to be relatively large, hindering their use on small diameter pipes, and using more material in the transducer wedge than is strictly necessary. The accuracy of the technique depends on a number of factors, and particularly on the accuracy of the compression wave speed in the liquid that is used in the calculations to obtain flowrate or heat transfer rate from the liquid in the pipe. Many flow meters either assume a value for the wave speed or obtain it using thermocouple measurements of the pipe exterior with a lookup table or simple equation. An error in the liquid ultrasonic velocity relates directly to errors in the calculated flowrate. It is highly beneficial if the ultrasonic wave speed in the liquid can be accurately measured in real time for flowrate calculations, especially for temperature and pressure varying conditions. A new type of small clamp-on ultrasonic transducer is reported, using a 6-mm-wide PEEK wedge that contains two piezoelectric elements, one of which generates sound normal to the flow direction, yielding the measurement of ultrasonic wave speed in the liquid. The new transducers were tested on a small rig with a 15-mm diameter copper pipe and a 70-mm diameter stainless steel pipe, yielding accurate measurements of liquid ultrasonic velocity and flowrates.

Molecular interactions of drug semicarbazide hydrochloride in aqueous-D-xylose/L-arabinose solutions at different temperatures: Volumetric, acoustic and viscometric study

The interactions of drug semicarbazide hydrochloride in water and in aqueous-carbohydrate (D-xylose/L-arabinose) solutions from their physicochemical behaviour are studied. Density, ρ, ultrasonic speed, u and viscosity, η of the drug semicarbazide hydrochloride in water and in aqueous-D-xylose/L-arabinose (5 wt% and 10 wt% of D-xylose/L-arabinose in water, w/w) solvents were measured as functions of concentrations at temperatures, T = (293.15 – 318.15) K and at atmospheric pressure, p = 101 kPa. The measured data have been utilized to calculate various properties like the apparent molar volume, Vφ from density measurements while apparent molar compressibility, Ks,ϕ, acoustic impedance, Z and intermolecular free length, Lf from ultrasonic speed measurements. The values obtained from these parameters indicate strong solute–solvent interactions within the solutions. The viscosity data have been analyzed using Jones-Dole equation and coefficients A and B were evaluated. The temperature derivative of B-coefficient, dB/dT together with activation parameters of viscous flow have also been determined. The results are discussed in terms of hydrophilic-hydrophilic and hydrophilic-hydrophobic interactions in these systems along with the structure breaking/making ability of the drug.

Optimized Blood Volume Monitoring during Hemodialysis Procedure based on Ultrasonic Speed Measurement

Fast reduction of blood water volume due to ultra-filtration via hemodialysis machine and critical threshold of blood water volume can result in clinical complications such as hypotension. When blood water volume reduces during hemodialysis process, the concentration of blood forming elements will increase. One of the methods for the monitoring of the concentration changes is ultrasonic speed measurement. In this paper, we optimize the ultrasonic speed measurement method in such a way that it would be compatible with conventional air detector in a hemodialysis machine. Air bubble detecting and the relative blood water volume estimating can be achieved by adding the “sing-around” ultrasonic speed measurement method to the current hemodialysis machine; air bubble detection is achieved by monitoring the decline in the ultrasonic wave amplitude (because of air bubbles) and the protein concentration measurement is achieved by measuring the transit time of the wave. Therefore, the optimized method can be applied to the air detection device of a hemodialysis machine.

Temperature dependent physicochemical studies of polyethylene glycols (PEG-400 and PEG-4000) in aqueous sorbitol solutions

From the measurements of density and speed of sound, the apparent molar properties and the partial molar properties have been determined to study the interactions of two polyethylene glycols i.e. polyethylene glycol 400 and polyethylene glycol 4000 in aqueous solutions of sorbitol at experimental pressure p = 0.1 MPa and temperatures T = (288.15–318.15) K. Evaluation of partial molar volume (Vϕo), apparent molar volume (Vϕ) and partial molar volumes of transfer (ΔVϕo) is done using density measurements. For the determination of partial molar isentropic compression (Kϕ, so), apparent molar isentropic compression (Kϕ, s), and partial molar isentropic compression of transfer (ΔKϕ, so), the ultrasonic speed measurements have been utilized. The limiting apparent molar expansibilities (Eϕ0) and its first order derivatives (∂Eϕ0/∂T)p are also calculated. Further, with the aid of partial molar isentropic compression of transfer and partial molar volumes of transfer, pair and triplet coefficients are determined. Through the scrutiny of these evaluated parameters, the results are elucidated based upon contending patterns of physicochemical interactions of co-solutes and solvents prevailing in present ternary liquid mixtures.

Acoustical and volumetric investigation of polyethylene glycol 400 and polyethylene glycol 4000 in aqueous solutions of glycerol at different temperatures

Abstract The intermolecular interactions of glycerol with two polyethylene glycols i.e. polyethylene glycol 400 and polyethylene glycol 4000 in aqueous medium have been examined from the measurements of density and ultrasonic speed at temperatures T = (293.15, 298.15, 303.15, 308.15) K and experimental pressure p = 0.1 MPa. The apparent molar volume ( V ϕ ), partial molar volume ( V ϕ o ) and partial molar volume of transfer ( Δ V ϕ o ) have been evaluated from density data for polyethylene glycols from water to aqueous glycerol solutions. The limiting apparent molar expansibilities have also been evaluated. The ultrasonic speed measurements are used to determine apparent molar isentropic compression ( K ϕ , s ), partial molar isentropic compression ( K ϕ , s o ) and partial molar isentropic compression of transfer ( Δ K ϕ , s o ) for polyethylene glycols from water to aqueous glycerol solutions. From (partial molar volume and partial molar isentropic compression) of transfer, the pair and triplet coefficients are calculated. By the perusal of these determined parameters, the results have been explicated based upon the competing patterns of physicochemical interactions of co-solutes and the solvents.

A new approach to correct yaw misalignment in the spinning ultrasonic anemometer

Single-axis ultrasonic anemometers are the modern instruments for accurate wind speed measurements. Despite their widespread and ever increasing applications, little attention has been paid up to now to spinning ultrasonic anemometers that can accurately measure both the wind speed and its direction in a single and robust apparatus. In this study, intensive wind-tunnel tests were conducted on a spinning single-axis ultrasonic anemometer to investigate the yaw misalignment in ultrasonic wind speed measurements during the yaw rotation. The anemometer was rotating inside the test section with various angular velocities, and the experiments were performed at several combinations of wind speed and anemometer angular velocity. The instantaneous angular position of the ultrasonic signal path with wind direction was measured using an angular position sensor. For a spinning anemometer, the circulatory wake and the associated flow distortion, along with the Doppler effect, impart a phase shift in the signals measured by the anemometer, which should be added to the position data for correcting the yaw misalignment. In this paper, the experimental data are used to construct a theoretical model, based on a response surface method, to correct the phase shift for various wind speeds and anemometer rotational velocities. This model is shown to successfully correct the velocity indicated by the spinning anemometer for the phase shift due to the rotation, and can easily be used in the calibration process for such anemometers.

A procedure for calibrating the spinning ultrasonic wind sensors

The accuracy of wind speed and direction measurements with spinning ultrasonic wind sensors is important than ever in today’s wind industry in which, they are usually installed on the hub of the wind turbines to measure the wind speed and direction for optimized power. In this paper, extensive wind-tunnel tests have been performed to calibrate the wind speed and direction measured by a spinning single-axis ultrasonic anemometer for both static and spinning conditions. This has been carried out with static measures at various stationary angles of transducers signal path with wind direction, and with dynamic measures in which the anemometer is rotating with various rotational speeds. The velocity measured by ultrasonic anemometer in static tests is calibrated with pitot-tube data, and the interpolation of obtained calibration coefficients is used to correct the ultrasonic velocity measured in dynamic tests. It is observed that the calibrated ultrasonic wind speed measurements in dynamic tests are in a good agreement with the reference velocity. According to the results, the ultrasonic velocity measurements in both static and dynamic tests are affected by the transducers head distortions, and the shifting in acoustic pulse trajectory due to the rotational motion does not affect the anemometer measurements. The uncertainty of the calibration process for the spinning tests was found to be about 0.3%.

Use of zinc stearate to produce highly-hydrophobic adobe materials with extended durability to water and acid-rain

This paper presents a novel solution to increase the durability of adobe materials using zinc stearate at doses ranging from 0.25% to 2.00% w/w. Shrinkage, apparent density and ultrasonic propagation speed measurements were performed on the cured samples. In addition, water absorption and durability features were determined by capillary tests, Karsten tube measurements, immersion in water, hydrochloric acid (5% w/w) and sulphuric acid (5% w/w) solutions. The durability study was complemented by rain erosion and acid-rain erosion tests. The capillary water absorption was comparable to that of hydrophobic cement renders and the acid-rain erosion was negligible in samples containing 1.00–2.00% w/w zinc stearate. Besides, SEM examination confirmed the protective action of zinc stearate in front of acid-rain. To conclude, zinc stearate was found to be was an excellent choice to increase the durability of adobe materials.

A study on behavior of steel structures subjected to fire using non-destructive testing

Due to its earthquake resistant properties, most building structures are constructed with reinforced concrete on a steel structure. As the temperature of steel increases especially during a fire, it will reduce the strength of a structure. Since the properties of steel, such as the Young’s modulus and yielding strength, drop rapidly with increasing temperature, during a fire the load capacity of such structures will decline dramatically. However, it is important to evaluate the structural performance of steel frames after a fire for reuse and reconstruction due to the high cost of reconstructive building. This study is concerned with the development of nondestructive testing techniques to investigate the structural behavior of steel subjected to fire. The results of ultrasonic wave speed measurement show that heating up to 1000°C and cooling by water produces a large change in wave speed. Under metallurgical microscope observation, the texture could be seen to have changed into bainite and martensite. In the study, the properties of the structure became hard and brittle due to phase change.

Ultrasonic characterization of seagrass leaf blades (Posidonia oceanica)

It has been shown that simple mixture theory models are inadequate to describe low-frequency sound propagation through seagrass meadows and further understanding of the acoustic properties of seagrass tissue is necessary. To that end, we present two ultrasonic sound speed measurements on the Mediterranean seagrass Posidonia oceanica. First, a transit time measurement through a stack of 120 leaf blades at 2.25 MHz are compared to similar measurements made on macroalgae Ecklonia radiata. Sound speed differences are related to the gas content within the aerenchyma of seagrass and other tissue characteristics. Second, ultrasonic sound speed measurements through a suspension of finely divided P. oceanica leaf blades at frequencies between 1 and 4 MHz are compared to low-frequency (1-8 kHz) sound speed obtained on the same blade suspension by means of a resonance chamber.

Newlight Technologies to use AirCarbon biocatalysis technology to convert methane

From the measurements of density and speed of sound, the apparent molar properties and the partial molar properties have been determined to study the interactions of two polyethylene glycols i.e. polyethylene glycol 400 and polyethylene glycol 4000 in aqueous solutions of sorbitol at experimental pressure p = 0.1 MPa and temperatures T = (288.15–318.15) K. Evaluation of partial molar volume (Vϕo), apparent molar volume (Vϕ) and partial molar volumes of transfer (ΔVϕo) is done using density measurements. For the determination of partial molar isentropic compression (Kϕ, so), apparent molar isentropic compression (Kϕ, s), and partial molar isentropic compression of transfer (ΔKϕ, so), the ultrasonic speed measurements have been utilized. The limiting apparent molar expansibilities (Eϕ0) and its first order derivatives (∂Eϕ0/∂T)p are also calculated. Further, with the aid of partial molar isentropic compression of transfer and partial molar volumes of transfer, pair and triplet coefficients are determined. Through the scrutiny of these evaluated parameters, the results are elucidated based upon contending patterns of physicochemical interactions of co-solutes and solvents prevailing in present ternary liquid mixtures.

Studies on liquid–liquid interactions of some ternary mixtures by density, viscosity and ultrasonic speed measurements

The density, viscosity and ultrasonic velocity have been measured for the ternary mixtures of Methyl benzoate, cyclohexane with primary alcohol (1-propanol, 1-butanol, 1-pentanol and 1-hexanol) at 303.15, 308.15 and 313.15K. From the measured values, the acoustical parameters such as adiabatic compressibility (β), free length (Lf), free volume (Vf) have been computed. The excess parameters like excess adiabatic compressibility (βE), excess free length (LfE), excess free volume (VfE) and excess internal pressure (πiE) were also calculated in order to investigate the molecular interaction between the components of liquid mixtures.

Solvation behavior of some amino acids in aqueous solutions of non-steroidal anti-inflammatory drug sodium ibuprofen at different temperatures analysed by volumetric and acoustic methods

Apparent molar volume (V∅), apparent molar isentropic compression (K∅,s) of glycine, l-alanine and l-valine in binary aqueous solutions of (0.05, 0.15, 0.25 and 0.35)mol·kg−1 sodium ibuprofen (Na-IBP) have been determined at temperatures (288.15, 293.15, 298.15, 303.15 and 308.15)K from density and ultrasonic speed measurements. Apparent molar volume at infinite dilution V∅0, apparent molar isentropic compression at infinite dilution K∅,s0 and the experimental slopes (SV and SK) were obtained from Masson’s equation. These values are used for calculating the number of water molecules hydrated (nH) to the amino acids. The structure-making/breaking ability of solutes was discussed using Hepler’s Criterion. Transfer parameters (ΔV∅0) and Δ(K∅,s0) at infinite dilution from aqueous to aqueous Na-IBP solutions have been calculated and were interpreted in terms of hydrophilic–hydrophilic, hydrophilic–hydrophobic and hydrophobic–hydrophobic interactions on the basis of co-sphere overlap model. The linear correction of V∅0 for a homologous series of amino acids has been utilized to calculate to contribution of the charged end groups (NH3+,COO-), (CH2) groups, and the other alkyl chain of the amino acids to V∅0. The pair and triplet interaction coefficients have also been calculated from both the properties. The volume and compression data suggest that hydrophilic–hydrophilic interactions are predominant in these systems. It is inferred that the effect of Na-IBP on protein stability need not be necessarily due to preferential hydration, it can also interact with the hydrophilic groups of the constituents of proteins affecting its stability.

Densities, Sound Speed, and Viscosities of Some Amino Acids with Aqueous Tetra-Butyl Ammonium Iodide Solutions at Different Temperatures

Apparent molar volumes (V⌀), apparent molar isentropic compression (K⌀,s), and viscosity B coefficient of glycine, l-alanine, and l-valine in (0.01 and 0.03) mol·kg–1 aqueous tetrabutyl ammonium iodide (TBAI) solutions have been determined at temperatures (288.15, 293.15, 298.15, 303.15, and 308.15) K from their experimental density, ultrasonic speed, and flow time measurements, respectively. Partial molar volumes (V⌀0) and partial molar isentropic compression (K⌀,s0) have been determined from the above measurements. Further, these data were used to calculate the corresponding transfer parameters (ΔV⌀,s0 and ΔK⌀,s0), hydration number (nH), side chain group contributions of V⌀0, and viscosity B coefficients of the amino acids, partial molar expansibilities (E⌀0), (dB/dT), and related parameters. The trends of variations of experimental and computed parameters have been discussed in terms of solute–solvent interactions with an emphasis on structure-making and structure-breaking ability of the above amino ac...

El concreto con agregados reciclados como proyecto de sostenibilidad urbana

This article addresses the preparation of a concrete using recycled aggregates obtained from the rubble recovery of concrete and masonry works. The study showssome aspects such as: compressive strength at 3, 7, 14, 28, 56 and 91 days; porosity, ultrasonic pulse speed and carbonation; economic costs compared to aconventional concrete; and a review of the public policies on sustainable construction and the use of rubble, in the city of Medellin, Colombia. For some mixes, thecompressive strength and the ultrasonic pulse speed measurements were approximately the 98% of that of the reference mix. Likewise, the mix prepared with 100%of recycled aggregates showed a difference in the carbonation deepness of only 0.7 mm compared with the mix of reference for a simulated age of 27 years. Theresults obtained with the replacement of natural coarse and fine aggregates in 25%, 50%, and 100%, and the advance in the political-administrative guidelines of thecity in the last eleven years, allow deducing the possibility of preparing structural and non-structural concretes for massive use in the construction area. Rev. ing. constr. [online]. 2015, vol.30, n.2, pp. 99-108. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732015000200002

Measurements of ultrasonic diffusivity and transport speed from coda waves in a resonant multiple scattering medium.

Frequency-resolved experimental measurements of ultrasonic diffusivity in the MHz range are presented. The samples under study are two-dimensional random arrangements of parallel steel rods immersed in water and exhibit high-order multiple scattering. Their physical characteristics, particularly the density and pair-correlation functions of the scatterers, are well controlled. These synthetic samples are used as phantoms for actual inhomogeneous materials. The resonant nature of the scatterers has a strong effect on diffusivity, which is shown to vary significantly with frequency. This may affect the result of broadband measurements of apparent diffusivity, which can be expected to depend on time and sample thickness, whereas diffusivity is intrinsically an intensive parameter. Moreover, the transport speed is shown to vary drastically with frequency, sometimes by more than 50%, due to a very narrow resonance that slows down transport. Interestingly, this sharp resonance could only be revealed by experiments performed with coda waves, and not with ballistic or coherent waves whose frequency resolution is intrinsically limited from an experimental point of view.

The aggregation behavior of trimetazidine hydrochloride in aqueous solutions at different temperatures

The aggregation behavior of trimetazidine hydrochloride (TMZ HCl) in aqueous solutions has been investigated by electrical conductivity, ultrasonic speed and density measurements in the temperature ranges from 298.15 to 313.15K, at 5K intervals. The critical micelle concentration (cmc) values of TMZ HCl in aqueous solutions were evaluated by using conductivity measurements. The conductivity values of the solutions have been employed to determine the critical micelle concentrations by applying the Williams definition and the Phillips method. Apparent molal volumes and isentropic compressibility values have also been calculated from the experimental density and ultrasonic speed data. The interionic interactions and hydrophilic–hydrophobic and hydrophobic–hydrophobic group interactions on TMZ HCl aqueous solutions have also been studied at different temperatures by using ultrasonic speed, density and conductivity measurements, respectively.

Ultrasonic speed, densities and viscosities of xylitol in water and in aqueous tyrosine and phenylalanine solutions at different temperatures

Ultrasonic speed u, densities ρ and viscosities η of xylitol in water and in 0.001 m aqueous l-tyrosine (Tyr) and l-phenylalanine (Phe) have been measured at different temperatures. From the density and ultrasonic speed measurements apparent molar isentropic compression $$ \kappa_{{S,{\kern 1pt} \phi }} $$ , apparent molar isentropic compressions at infinite dilution $$ \kappa_{{S,{\kern 1pt} \phi }}^{0} $$ , experimental slope S K , hydration number n H , transfer partial molar isentropic compressibility $$ \Delta_{tr} \kappa_{{S{\kern 1pt} ,\phi }}^{0} $$ of xylitol from water to aqueous Tyr and Phe have been obtained. From the viscosity data, B-coefficient and B-coefficient of transfer Δ tr B of xylitol from water to aqueous Phe and Tyr at different temperatures have also been estimated. Gibbs free energies of activation of viscous flow per mole of solvent Δμ 1 0# and per mole of solute Δμ 2 0# have been calculated by using Feakins transition state theory for the studied systems. The calculated parameters have been interpreted in terms of solute–solute and solute–solvent interactions and hydration behavior of xylitol.