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The present work focuses on the ultrasonic characterisation of the binary mixture having constituent liquids, 2,3-dichloroaniline and methanol/ethanol, by measuring their density, viscosity, ultrasonic velocity and estimating thermo-physical parameters at 25°C. The density, viscosity, ultrasonic velocity, acoustic impedance and relative association decay, while compressibility and free length increase with the increase in mole fraction of solvent in the present binary mixture. An anomalous change is received in excess molar volume, free volume, thermal relaxation time, Gibbs free energy and ultrasonic absorption up to 80% solvent mole fraction. The analysis reveals that the binary mixture 2,3-DCA+ methanol has a good intermolecular interaction strength, and is more structural and less corrosive than 2,3-DCA+ ethanol due to the formation of excess hydrogen bonding at 70% solvent mole fraction. [ABSTRACT FROM AUTHOR]

A creative engineer tends to understand the principles and phenomena not only based on mathematical physics but also by intuition. Author has picked up several topics among such principles and phenomena in the area of medical ultrasound and challenges to explain them intuitively in this article. The chosen topics are the lateral resolution, Doppler blood flow measurement, a piezoelectric element, ultrasonic absorption by biological tissues, and intensive/extensive variables. Author hopes that the presented intuitive explanation will help the readers to enhance their creativity as an engineer [ABSTRACT FROM AUTHOR]

Biodiesel is a good alternative to Petroleum Diesel (PD). The storage of fuel is unavoidable for its future use. The objective of the study was to investigate ultrasonic parameters: viscosity, relaxation time, ultrasonic absorption and Gibb’s free energy for 2-year long-term stored biodiesels and blends with PD. The two biodiesels were Cotton Seed Oil Methyl Esters (CSOME) and Palm Stearin Methyl Esters (PSME). Five biodiesel blends with PD in 10, 20, 30, 40 and 50 volume per cent were studied at the room temperature of 301 K. The fatty-acid profiles were also investigated using GC–MS chromatographic analytical tool and the viscosity was determined using an Ostwald viscometer. Ultrasonic velocity was measured with an ultrasonic interferometer of fixed frequency 2 MHz. The results show that CSOME biodiesel contains 13.47 and 86.53 weight per cent of low molecular weight nonpolar and high molecular weight polar compounds, respectively, and PSME biodiesel with 38.66% and 61.33%, respectively. The measured parameters increased for both the biodiesel blends due to storage. The increase in CSOME blends is more than that in PSME blends. For CSOME blends, highest and lowest changes are 64.28% and 4.48% for 10% volume blend of viscosity and pure CSOME biodiesel of Gibb’s free energy, respectively. In PSME blends, they are 31.25% for 10% volume blend of viscosity and zero for 50% volume blend of Gibb’s free energy. The highest difference occurred for 50% volume blends between old CSOME and PSME blends. From the overall results, it is concluded that variations of the measured parameters strongly depend on the fatty-acid profile of biodiesels due to storage. [ABSTRACT FROM AUTHOR]

Highlights • The analytic function K(y) is modified for the five mode-coupling theories. • A similarity is found for Fixmen and Kawasaki experimental scaling function. • The modification of the analytic function predicts an excellent agreement between theoretical and experimental data for sound propagation in binary liquid mixture. Abstract The mode-coupling theory of Fixmen, Kawasaki, Hornowski, Mistura, and Chapan failed to explain the experimental behavior of the binary liquid mixtures at critical composition and above critical temperature. The analytic function of Fixmen's, Kawasaki's, Hornowski's, Mistura's, and Chapan's theories was modified in order to get an agreement with the experimental behavior of the binary liquid mixtures at critical concentration and above the critical temperature. [ABSTRACT FROM AUTHOR]

Biodiesel is an environmental friendly alternative fuel for petroleum diesel (PD). It can also be used as blend component with PD. In the present study, the ultrasonic absorption of cotton seed oil methyl esters (CSOME) and palm stearin methyl esters (PSME) biodiesels and their blends with PD have been measured and analyzed as a function of fatty acid profiles of biodiesels. The CSOME that are rich in unsaturated fatty acid methyl esters (FAME) have shown more absorption than PSME which are rich in saturated FAME as there is difference in the structures of saturated and unsaturated fatty acids. The reason for the absorption may be due to the molecular relaxation phenomenon of methyl ester molecules. The ultrasonic absorption may be more in blends than in pure oils. [ABSTRACT FROM PUBLISHER]

The Navier-Stokes (N-S) equations for a steady or unsteady, compressible, continuum flow are modified. The extension is based on a Stokesian fluid with a single nonlinear term in an isotropic stress, rate-of-deformation relation. This is the simplest possible nonlinear extension that also satisfies the second law of thermodynamics. The transport coefficient of this term is referred to as the third viscosity coefficient. In the extended version, the momentum and energy equations each contain a nonlinear term that is proportional to this new coefficient. These terms are significant only when the velocity gradient is extremely large. They are inconsequential, e.g., in a laminar boundary layer. Nevertheless, there are flows where the extended version of the N-S equations is relevant. The first of these is an ultrasonic, unsteady, one-dimensional flow, which is used for evaluating the bulk viscosity. In this case, the linearized N-S equations become singular as the ultrasonic frequency increases toward infinity. When the frequency is sufficiently large, nonlinear terms in the extended N-S equations need to be retained. The terms that are proportional to the third viscosity coefficient increase in importance, relative to linear terms, as the fourth power of the frequency. A second example is shock wave structure. A model is established and numerically solved for the normalized density derivative. Results are compared with corresponding measurements for argon when the upstream Mach number is 1.058 and 1.23. Good agreement between the extended N-S predictions and measurements is obtained for both Mach numbers with a single, but extremely small, value for the third viscosity coefficient. An important difference between conventional and extended N-S shock structure solutions is that the extended-model solution depends on the upstream pressure, whereas the conventional solution does not. [ABSTRACT FROM AUTHOR]

Guided wave has been utilised in various manners for non‐destructive evaluation and testing. The dispersion and attenuation characteristics of guided wave restrict and complicate the accurate estimation of echo propagation distance. The study focuses on how to reduce the estimation error of propagation distance caused by these characteristics. The propagation of guided wave with attenuation and dispersion characteristics is analytically modelled in general cases. The flight‐time compensation technique is developed based on the analytical model of wave propagation and the algorithm of chirplet matching pursuit. Numerical simulations are given to verify the efficacy of the developed compensation method. Finally, this study demonstrates the use of experimentally measured data for echoes identification and propagation distance estimation. [ABSTRACT FROM AUTHOR]

Ultrasonic relaxation studies have been carried out in aqueous solutions of biological surfactants namely bile salts (sodium cholate and sodium deoxy cholate) at 303.15 K in the concentration range 1 to 14 mM and in the frequency range 2–30 MHz. The ultrasonic velocity is determined at 2 MHz using a Digital Ultrasonic velocity meter. The ultrasonic absorption is measured in the frequency range 2–30 MHz using Fallen Instruments and Pulsed Power Oscillator systems. The variation in the ultrasonic absorption is explained on the basis of exchange of a surfactant monomer between the micelles and the surrounding bulk solution. An attempt has also been made to extend the application of Aniansson and Wall and Teubner models to explain the micellar kinetics of biological surfactants which is otherwise applied to explain the kinetics of ordinary surfactants only. Various kinetic parameters such as associative rate constant (k + 1 ), dissociative rate constant (k − 1 ) and the volume change (∆V) for the monomer–micelle exchange are estimated and reported in this paper. [ABSTRACT FROM AUTHOR]

Purpose: Attenuation imaging has a promising role in the detection of tissue abnormalities. The authors have previously compared three different frequency domain ultrasound attenuation estimation methods, for accuracy and bias. The mean estimated attenuation value in a region of interest has been the determining factor of how well a method performs; however, the noise level has not been quantified for attenuation estimated using different methods. Methods: The authors compare three different frequency domain ultrasound attenuation estimation methods [the reference phantom method (RPM), the centroid downshift method (CEN), and the hybrid method (HYB)] using the signal to noise ratio (SNR) metric. Both simulated and experimental tissue-mimicking phantoms are used in the performance comparison study, evaluating the impact of the variation in acoustical properties. Results: For attenuation estimation in a tissue-mimicking phantom with a known attenuation coefficient of 0.5 dB/cm/MHz, all the three methods estimated the attenuation coefficient to be 0.49 dB/cm/MHz for a transmit center frequency of 6 MHz, however, the signal to noise ratio obtained was found to be 8.5, 5.7, and 2.2 for the HYB, RPM, and CEN methods, respectively. These results demonstrate the need for the SNR metric in the comparison of different algorithms and to evaluate the impact of varying different ultrasound system and tissue parameters Conclusions: In this paper, the authors demonstrate that although the estimated mean attenuation value with a region of interest may be closely estimated using different methods, the signal to noise ratio obtained of the estimates can vary significantly. The centroid downshift method presented with the lowest signal-to-noise ratio of the methods compared. The hybrid method was the least susceptible to changes in the acoustical properties and provided unbiased attenuation coefficient estimates with the highest signal-to-noise ratios. [ABSTRACT FROM AUTHOR]

Purpose: This paper describes a feasibility study for developing a 35-MHz high-frequency ultrasound computed-tomography (HFUCT) system for imaging rat testicles. Methods: The performances of two kinds of HFUCT-attenuation and sound-speed UCT-based on transmission and pulse-echo modes were investigated in this study. Experiments were carried out using phantoms and actual rat testicles in vitro. HFUCT images were reconstructed using a filtered backprojection algorithm. Results: The phantom experimental results indicated that all types of HFUCT can determine the dimensions of a plastic cylinder with a diameter of 500 μm. Compared to sound-speed HFUCT, attenuation HFUCT exhibited a better performance in recognizing a tiny sclerosed region in a gelatin phantom. Therefore, the in vitro testicular experiments were performed using attenuation HFUCT based on transmission and pulse-echo modes. The experimentally measured attenuation coefficient and sound speed for healthy rat testicles were 2.92 ± 0.25 dB/mm and 1537 ± 25 m/s, respectively. Conclusions: A homogeneous texture was evident for healthy testicles using both modes. An artificial sclerosed tumor could also be clearly observed using two- and three-dimensional attenuation HFUCT in both modes. However, an object artifact was apparent in pulse-echo mode because of ultrasound beam refraction. All of the obtained experimental results indicate the potential of using HFUCT as a novel tool for monitoring the preclinical responses of testicular tumors in small animals. [ABSTRACT FROM AUTHOR]

Highlights: [•] Density, ultrasonic velocity and ultrasonic absorption are measured in sodium cholate and sodium deoxycholate in water and water–10% (v/v) of aprotic solvent mixtures at 303.15K and at 2MHz frequency, respectively. [•] From the measured data, various parameters such as apparent molar volume, apparent molar compressibility, hydration number, equivalent conductivity, adiabatic compressibility and intermolecular free length are calculated. [•] The negative values of apparent molar volume have been discussed in terms of structured water present around the solute molecules. [•] The negative values of apparent molar compressibility have been discussed in terms of hydrogen bonding and hydration. [•] The variation of ultrasonic absorption with concentration of bile salts in water and water–aprotic solvent mixtures is explained in terms of making and breaking of hydrogen bonds when the ultrasonic waves pass through the medium. [•] The CMC values obtained for bile salts in water and water–aprotic solvent mixtures in the present study agrees well with the equivalent conductivity measurements. [ABSTRACT FROM AUTHOR]

Measurements of the sound absorption coefficient in test objects containing solid microparticles randomly distributed over the object volumes are carried out. Two methods are used for this purpose: the standard echo-pulse insert-substitution method and a modified method using phase conjugation of ultrasound. The test objects are made from gelatin, and the size of the particles introduced in it is chosen to allow measurements in both the long- and medium-wavelength scattering modes of the probing beam. It is shown that, in the first scattering mode, in which the presence of particles causes additional viscous and temperature losses, the two aforementioned methods give identical results. In the second scattering mode, in which the dominant mechanism of additional loss is elastic scattering, the use of phase conjugation allows an almost complete reconstruction of the scattered field and, hence, a more reliable upper estimate for the coefficient of ultrasonic absorption in the test objects. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, a novel application of ultrasonic measurements is detailed to characterize nano-emulsion formulations as a part of the overall Quality by Design (QbD) goal. Ultrasonic resonator technology (URT) was utilized to measure sound velocity and absorption of self-nanoemulsified drug delivery systems (SNEDDs) consisting of various ratios of oil:surfactant:co-surfactant. A QbD concept was used to create different SNEDDs formulations utilizing sweet orange oil (oil), Emulphor-620 (surfactant), and Capmul (co-surfactant) by dissolving Cyclosporine A in oil. The mixture was emulsified in water and ultrasonic measurements were carried out in an ultrasonic resonator system isothermally for a period of about 15–20min. Compressibility of the individual components in the droplets, hydration of the droplets and the influence of the composition on droplet stability were studied by systematic ultrasonic measurements at a single resonator frequency. The adiabetic compressibilities for the oil, aqueous and interfacial components were 68, 44.6, and 53 [10−11 Pa−1], respectively as calculated using Urick''s equation. Also the ultrasonic absorption correlated droplet size of nano-emulsions linearly with R 2 of 0.84 indicating this can be used as an additional technique to measure the droplet size of nano-emulsions. Correlation of ultrasonic data with formulation components indicated that the ultrasonic velocity correlated negatively with increasing oil amount in the formulation as well as surfactant-to-cosurfactant ratios where as droplet diameter correlated positively with these formulation factors. It can be envisioned from the results that the compressibility of the media increases with the addition of the oily component and thus reducing the sound velocity. Thus URT enabled direct and convenient analysis of the physical properties as well as influence of formulation factors of nano-emulsions which is an important indication of stability of these nano-emulsions. [Copyright &y& Elsevier]

Abstract: Acoustic wave detection of various underivatized amino acids that were hydrodynamically introduced into and electrokinetically migrated along a capillary tube has been achieved. The detection principle is based on the measurement of the ultrasonic absorption and density change of the aqueous amino acid samples as they pass by the detection zone. Acoustic wave detection of underivatized leucine was obtained in the ultrasonic frequency range of 100kHz to 20MHz. This was accomplished by measuring the insertion loss from the vector ratio of the signal voltage to the source voltage obtained at the generating and receiving piezoelectric transducers. Linear concentration dependence of the insertion loss of underivatized leucine was established. The effects of capillary internal diameter, capillary geometry (square and circular), buffer concentration, buffer pH and acoustic wave frequency on the insertion loss were investigated. Subsequently, separations of underivatized amino acids (leucine/histidine and leucine/tryptophan) were performed under different buffer conditions and different capillary geometry. [Copyright &y& Elsevier]

Summary: The results of acoustic measurements of velocity and absorption in three pure liquids: thiophene, p-and m-xylenes and their mixtures are presented. The experiments for the mixtures of thiophene were carried out by Eggers'' method at frequencies 0.3–5MHz, and for pure liquids by the pulse method in the frequency range 10MHz–10GHz, all at 293.15K except for thiophene (at 281 and 333K). The absorption in thiophene shows that all vibrational degrees of freedom take part in the observed relaxation, caused by the Kneser processes. This process can be described as a vibrational relaxation with one relaxation time. Absorption in the mixtures decreased when increasing the amount of xylenes, as predicted by theory of gases, thus suggesting that the absorption is probably due to the same phenomenon as in gases. [Copyright &y& Elsevier]

Abstract: Biocompatible magnetic fluids of nanoparticles coated with polyethylene glycol show stable acoustic properties up to a field intensity of . In higher fields, the ultrasonic wave absorption coefficient significantly increases and is strongly dependent on temperature, magnetic field intensity, magnetic field sweep rate and time of exposure to magnetic field. Adjustment of these parameters leads to control of the acoustic properties of the magnetic ferrofluids. [Copyright &y& Elsevier]

Ultrasonic absorption in polymer gel dosimeters was investigated. An ultrasonic interferometer was used to study the frequency (f) dependence of the absorption coefficient (α) in a polyacrylamide gel dosimeter (PAG) in the frequency range 5–20 MHz. The frequency dependence of ultrasonic absorption deviated from that of an ideal viscous fluid. The presence of relaxation mechanisms was evidenced by the frequency dependence of α/f2 and the dispersion in ultrasonic velocity. It was concluded that absorption in polymer gel dosimeters is due to a number of relaxation processes which may include polymer–solvent interactions as well as relaxation due to motion of polymer side groups.The dependence of ultrasonic absorption on absorbed dose and formulation was also investigated in polymer gel dosimeters as a function of pH and chemical composition. Changes in dosimeter pH and chemical composition resulted in a variation in ultrasonic dose response curves. The observed dependence on pH was considered to be due to pH induced modifications in the radiation yield while changes in chemical composition resulted in differences in polymerisation kinetics. [Copyright &y& Elsevier]

Changes in the materials microstructure caused by fatigue processes affect the ultrasonic absorption. Thus, quantitative measurement of the ultrasonic absorption should provide an indirect measure of fatigue damage. In this paper we present a study of the ultrasonic absorption in fatigue-damaged metals using the reverberation technique in combination with laser-based ultrasound. The reverberation technique allows one to measure absorption independently of scattering. [Copyright &y& Elsevier]

A modified treatment of ultrasonic pulse-echo immersion technique is formulated to permit experimental determination of the amplitude reflection coefficient and the ultrasonic attenuation coefficient α especially when the acoustic impedance of the measured specimen is far from that of the immersion liquid. The modified treatment is tested experimentally on blends of styrene–butadiene rubber (SBR 1502) and natural rubber (SMR 20) containing different concentrations of high abrasion furnace black. The effect of changing the immersion liquid on the obtained values of α is studied by using distilled water and ethyl alcohol as immersion liquids. The effect of changing the specimen thickness is also investigated. It is found that neither the immersion liquid nor the specimen thickness has any effect of the obtained values of α if the present modification is adopted. [Copyright &y& Elsevier]

• Ultrasonic Characterization of binary mixture of 2,3- Dichloroaniline with PEGs. • Measurement of density, viscosity and ultrasonic velocity at 27 °C and 1 atm. • Estimation of mole fraction dependent thermo-physical properties. • Characteristic determination based on elastic, thermal and ultrasonic parameters. • Explanation of molecular interaction, stability and structural ordering. The present study is focused on the ultrasonic characterization of binary mixture having constituent liquids 2,3-dichloroaniline as solute and polyethylene glycols (PEGs) with average molecular weight 200, 400 and 600 as solvent by measurement of density, viscosity, ultrasonic velocity and estimation of thermo-physical parameters at 27 °C and atmospheric pressure 100.3 kPa. The density and acoustic impedance are received to decay while viscosity, ultrasonic velocity, adiabatic compressibility, free length, internal pressure, thermal relaxation time, Gibbs free energy and ultrasonic absorption are found to enhance with an increase in mole fraction of solvents in synthesized binary mixtures The analysis of measured and estimated parameters reveal that the molecular interaction, structural ordering and stability of binary mixture shall enhance with increase in molar mass/mole fraction of PEGs. The ultrasonic absorption is found to be predominantly affected by viscosity. The present study is useful in chemical/pharmaceutical industries and further investigation. [ABSTRACT FROM AUTHOR]

The acoustic absorption of protein solutions in the presence of phosphate and other buffering ions has been studied in the physiological pH range. Buffers containing hydroxyl residues as titratable groups cause a pronounced increase of protein sound absorption, which is attributed to relaxation processes of proton transfer reactions between buffer ions and accessible imidazole and α-amino groups of the protein surface. Amino group based buffers like Good's buffers do not induce additional sound absorption. Measurement of the ultrasonic absorption as a function of pH and of buffer concentration, and corresponding parameter fitting of the equation describing proton transfer relaxation processes has been used to evaluate equilibrium parameters. For the imidazole group of the amino acid histidine a pK value of 6.22 and for the imidazole group of the protein lysozyme a pK value of 5.71 have been determined. In hemoglobin the ligand-linked pK changes have been monitored by recording ultrasonic titration curves. [ABSTRACT FROM AUTHOR]

Interpenetrating networks are the most recent development in polymeric blend materials. Due to the crosslinking of both the continuous and dispersed phases, a high degree of molecular mixing is achieved in these materials. Notwith-standing that poly(methyl methacrylate)-polyurethane (PMMA-PUR) interpene-trating and semi-interpenetrating networks have been extensively investigated by Meyer et al., ultrasonic relaxation technique has been applied here for the first time. These materials were found to be highly ultrasound absorbing. It is observed that ultrasonic absorption has a peak at a particular composition of PMMA-PUR interpenetrating network. The absorption coefficient α increases with frequency f. The absorption is of relaxational nature and is not due to the scattering of ultrasonic waves by the domains of the dispersed phase. At every composition of the interpenetrating network, the α/f vs. f curve indicates the presence of a relaxation frequency below 2 MHz and that the absorption increases with the temperature at some compositions which indicates the presence of thermal relaxation. An attempt is made to relate the absorption with the relaxation of pendent groups of polyurethane in the continuous phase. [ABSTRACT FROM AUTHOR]