Determination Of Ultrasonic Velocity Research Articles

Pirinç Kabuğu Külü Katkılı Harçların Dayanım Ve Dayanıklılık Özelliklerin Araştırılması

Bu çalışmada, tarımsal atık malzemesi olan Pirinç kabuğu külü, çimento yerine ağırlıkça %0, %2, 4%, 6%, 8%, 10%, ve %15 oranlarda kullanılarak toplam 7 farklı bileşime sahip harç numunesi üretilmiştir. Üretilen harç numuneleri üzerinde 28, 56 ve 90 günlük kür süreleri sonunda basınç dayanımı tespitinin yanında 56 günlük kür sonunda donma-çözülme ve ultrasonik hız tayini deneyleri de yapılmıştır. Çalışmada kullanılan bütün karışımlarda Su/Bağlayıcı oranı 0.50 oranında sabit tutulmuştur. Üretilen harç numunelerine ait sonuçlar değerlendirildiğinde %8 Pirinç kabuğu külü ikameli harçların daha yüksek dayanım ve dayanıklılık sonuçları verdiği tespit edilmiştir.

Experimental Method of Ultrasonic Sensor for Ions and Solutions Discrimination and Identification

The ultrasonic wave or vibration causes the deformation of the medium such as process of forming weld during construction of metallization contacts in semi-conductors. From that we propose to build a special circuit using ultrasonic sensor to discriminate mediums and materials. The spread of wave made by multipath limits the transmission speed. Generally, if the delay spread is the bigger so velocity is low. Thereon, we study the influence of ions in various solutions on the pressure by result on the directivity of ultrasonic wave. Each chemical solution has its appropriate properties that affect ultrasonic wave pressure according to the compression and dilatation of the medium. The goal of the current work is determination of ultrasonic velocity by result identification of chemical solutions. Above that the used method permit to propose an approach that permit to predict the ultrasonic wave velocity and the matching impedance of a mixture of mediums referring to their chemical composition.

Ultrasonic Velocity & Other Related Parameters

Ultrasonic velocity is an important parameter, characterizing the state of the system. It can be determined experimentally by using Ultrasonic Interferometer. A brief discussion of ultrasonic interferometer and mode of determining ultrasonic velocities is given. The present paper deals with the experimental determination of ultrasonic velocities and adiabatic compressibility’s of ethylene glycols and higher homologous. From the ultrasonic velocity, closely related parameters like molar sound velocity, molar compressibility, and Vander Waal’s constant ….etc. are evaluated. The variations in ultrasonic velocity and related parameters with degree of polymerization and a phenomenal reasoning for the same are also permuted.

Mechanical Characterization of Apricena Marble by Ultrasonic Immersion Tests

We characterize the elastic response of Apricena marble by using advanced ultrasonic nondestructive techniques. An innovative experimental device for ultrasonic immersion tests is employed for the determination of ultrasonic velocities of waves travelling into the sample for any angle of propagation. The interpretation of the experimental results within the theoretical framework of wave propagation in elastic materials allows for both the classification of the anisotropy and the determination of the elastic moduli.

Determination of Ultrasonic Velocities Theoretically for Tellurite Glasses Using Makishima and Mackenzie Model

Determination of Ultrasonic Velocities Theoretically for Tellurite Glasses Using Makishima and Mackenzie Model

Direct measurement of acoustic impedance in liquids by a new pulse echo technique

For the first time a novel experimental technique has been used for direct evaluation of acoustic impedance of liquids. Till date researchers have been using ultrasonic velocity and density measurements to compute acoustic impedance and thermodynamic parameters, which are then used to investigate the nature of molecular interactions of solvent molecules in binary, ternary and quaternary liquid mixtures. Evaluation of acoustic impedance directly is a step in minimizing the cumbersome process of measuring velocities and densities separately of solutions having different mole fraction concentration. Acoustic impedances of ten pure polar and non polar solvents have been determined at different temperatures of 298K, 303K and 308K. This is further coupled with inline simultaneous determination of ultrasonic velocities of the solvents. In order to establish the new method, results have been discussed by comparing the calculated ultrasonic velocity from the experimental acoustic impedance, ultrasonic velocity determination by delay time of flight and the literature values of ultrasonic velocity of the pure solvents.

An investigation of pulse-timing techniques for broadband ultrasonic velocity determination in cancellous bone: a simulation study

Berlage wavelets are used to simulate ultrasonic pulses in an unbounded, homogeneous, isotropic and absorptive medium. Intrinsic absorption of the medium is properly described by Kolsky's attenuation, which considers velocity dispersion to meet the causality condition. Several current time-domain velocity measurement techniques have been investigated using numerically simulated pulses for three normalized BUA values: 20, 40 and 60 dB , which mimic experimentally determined values for cancellous bone. The velocities, calculated using first motion transit times, are used as references supported by the Fermat principle of least time. The simulated results for fixed sample thickness indicate that pulse-broadening increases with the transit time of the reference point and the intrinsic absorption of the medium. Comparison shows that the first zero-crossing method yields 3-6% errors in velocity results, better than the cross-correlation method. However, the zero-crossing method gives inconsistent velocity measurement for a medium of 40 dB absorption and three different thicknesses: 0.2, 0.4 and 0.6 cm. A novel technique for velocity measurement is presented using the peak of the envelope of a signal as a reference point to measure transit time difference. The envelope of a signal represents the instantaneous amplitude of the associated analytic signal. The velocities derived using this method differ from the true velocities by only 1.2-2.4%, more accurate than those obtained by the first zero-crossing method. The envelope peak has the additional merits of easy detection and robustness. Most importantly, the envelope technique may be used to yield accurate velocity measurement in cases where an accurate determination of the first motion transit time is sometimes prohibited due to the presence of noise.

Determination of ultrasonic velocity and attenuation by wavelet analysis of echo waveform : Journal of JSNDI, Vol. 46, No. 3 p. 206 Inoue, H.; Kishimoto, K.; Nakanishi, T.; Hori, J.; Arai, M.; Shibuya, T.

Determination of ultrasonic velocity and attenuation by wavelet analysis of echo waveform : Journal of JSNDI, Vol. 46, No. 3 p. 206 Inoue, H.; Kishimoto, K.; Nakanishi, T.; Hori, J.; Arai, M.; Shibuya, T.

A comparison of time-domain and frequency-domain approaches to ultrasonic velocity measurement in trabecular bone

Different methods for ultrasonic velocity determination using broad-band pulse transmission have been investigated in 70 human calcanae in vitro. The work took place within the context of the EC BIOMED1 concerted action Assessment of Quality of Bone in Osteoporosis. Ultrasonic velocities were determined using three different transit time definitions: first arrival (TTV1), thresholding (TTV2), and first zero crossing (TTV3). Phase velocity (PV) was determined over a range of frequencies from 200 to 800 kHz using a new phase spectral analysis technique. The different velocity measurements were compared in terms of their magnitudes and their inter-correlations. There were significant differences of up to between different transit time velocities (p < 0.0001), indicating the sensitivity of the measurement to the arrival criteria used. Phase velocities were lower than all of the transit time velocities (p < 0.0001) and decreased with increasing frequency (p < 0.005). A strong correlation was observed between PV at 400 kHz (PV400) and TTV3, with much weaker correlations between PV and the other transit time velocities. Reproducibility for transit time velocity measurement was optimal for TTV3 (coefficient of variation, cv = 0.41%), and for PV it was optimal at 600 kHz (cv = 0.34%). These data indicate that transit time measurements may be subject to errors due to the modification of the pulse shape during propagation through bone by attenuation and dispersion. Velocity measurement by phase spectral analysis appears to offer advantages over the transit time approach, and should be the method of choice for velocity measurement in trabecular bone. Where transit time velocity measurements are made, the first-zero-crossing criterion appears to be have some advantages over other arrival criteria. We also note that PV measurements provide new information on dispersion which could prove to be relevant to the structural and mechanical characterization of trabecular bone.

Simultaneous determination of ultrasonic velocity, plate thickness and wedge angle using one-sided contact measurements

Traditional ultrasonic thickness gauging is based on the assumption that the ultrasonic velocity is known. In actual applications the velocity is often not well known and access is often limited to one side. This paper describes methods for determining the ultrasonic velocity and thickness of plates with parallel or wedged surfaces using contact measurements made on one surface only. For wedged plates the thickness at one point and the wedge angle are determined. Equations are derived for determining the ultrasonic velocity, thickness and wedge angle of the plate based on the times-of-flight measured by two contact transducers coupled to one surface. The time-of-flight to the obliquely reflected longitudinal wave echo was measured as a function of the separation (‘skip distance’) between the two transducers. In addition, the times-of-flight of normal-incident, pulse-echo longitudinal waves from each of the two transducers are also used. Experiments were performed on flat and wedged plates of various materials; the calculated results for the unknown quantities are generally accurate to a few percent.

Ultrasonic velocity determination of the phase diagram of UPt 3

We report ultrasonic velocity measurements on two UPt 3 samples with three different field orientations (H⊥c, H//c and H∧c=45°). Velocity changes are observed at constant temperatures, as the field is swept, at the upper critical field H c2 and at the flux lattice transition H fl. Velocity changes are also observed at T c + the upper transition temperature and T c - the lower transition temperature as the temperature is swept at constant fields. Complete phase diagrams for UPt 3 obtained by a single measurement technique on the same samples in the H-T plane are presented.

Determination of ultrasonic velocity in human enamel and dentine

Acoustic velocity data have been obtained preparatory to investigation of high frequency ultrasound as a non-invasive imaging technique for dental hard tissues and their pathology. In vitro studies were conducted on extracted human permanent teeth. Pulse-echo ultrasound of 18 MHz centre frequency and approx. 150 ns pulse duration successfully detected the front and back surfaces of 0.45 – 1.07 mm thick sections of enamel and of dentine. Water was used as the coupling agent. The oscilloscope traces of the echoes from pure enamel and pure dentine were similar. The longitudinal ultrasonic velocities for pure enamel and dentine were experimentally determined for a number of teeth in different planes of section. For enamel in longitudinal and transverse sections, the mean ultrasonic velocities were 6150 ± 140 and 6500 ± 190m/s respectively. For dentine in longitudinal section, the mean ultrasonic velocity was 4050 ± 30m/s.

Nondestructive determination of ultrasonic velocity and absorption in thin dielectrics by laser‐induced pressure pulses

The laser‐induced presure pulse (LIPP) generation of acoustic impulses in the 0.5‐ns range allows the measurement of ultrasonic velocity and absorption in thin dielectrics in the 0.2‐ to 1‐GHz range. This optoacoustic method generates ultrasonic pulses by thermoelastic effects and ablation due to absorption of 70‐ps laser‐light pulses in an opaque coupling layer deposited on one of the sample surfaces. Detection of the acoustic pulses is possible by using electrically charged or piezoelectric samples which yield electrode signals upon transit of the pulse. The sound velocity and absorption is determined from the relative delays and spectra, respectively, as the pulse is reflected from the sample surfaces. Multiple LIPP by splitting the laser beam into two time (or more) components and delaying one component relative to the other by a time T results in a boost of the spectrum at the frequency f = 1/T. Measurements on several polymers with this technique gives sound speed close to the values determined for the bulk material and attenuation coefficients that rise almost linearly with frequency in the range 0.2–1 GHz.

Determination of ultrasonic velocity in liquids using optical diffraction by short acoustic pulses

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An investigation of the validity of ultrasonic pulse-superposition velocity measurements using thin-film transducers

Analysis of the phase shift of ultrasonic waves on reflection at a bonded transducer is extended to the case of thin-film piezoelectric transducers and is complemented by measurements. The certainty of determination of ultrasonic velocities by use of thin-film transducers is shown to be much greater than that attained by bonded-transducer techniques.A direct comparison is drawn between sampled-continuous-wave resonances and pulse-superposition pseudoresonances in ultrasonic samples. To justify this comparison, measurements of ultrasonic transit times in GaAs single crystals have been made by both techniques, using thin-film CdS transducers. The validity of use of the pulse-superposition technique to make accurate measurements of ultrasonic velocities is demonstrated.

Determination of Ultrasonic Velocities by Measurement of Angles of Total Reflection

A simple method, based on the total reflection of a sound beam from a liquid-solid boundary at the critical angles, is described. With this method, it is possible to measure the velocity of longitudinal and shear waves in the solid by locating the angles of maximum reflection in the liquid.

A New Precision Method for the Measurement of Ultrasonic Velocities in Liquids

SEVERAL methods1 are available for the determination of ultrasonic velocities in liquids, of which the liquid film method2 offers many advantages. The new method presented here enables a rapid determination of ultrasonic velocities with a high degree of accuracy.

An Experimental Determination of Ultrasonic Velocity in Several Gases at Pressures Between One and One Hundred Atmospheres

An acoustic interferometer of the resonator or driven type has been developed for the study of the behavior of ultrasonic waves in gases under pressures ranging from vacuum to several hundred atmospheres; measurements of acoustic velocity at several frequencies and in several gases at pressures ranging from one to 100 atmospheres have been made. Increase of velocity with pressure was found for air, N2, He, and H2, a decrease for CO2, the approximate pressure and velocity ranges being respectively as follows: air, 1–101 atmos., 347–371 m/sec.; N2, 1–102 atmos., 353–380 m/sec.; CO2, 1–63 atmos., 270–198 m/sec. The He and H2 were known to be impure. For them an increase in velocity nearly linear with pressure was found. Using frequencies from 88 to 499 kc dispersion was found for CO2 at atmospheric pressure, but almost entirely disappeared above 8 atmospheres. The availability of this method for the indirect determination of specific heats is shown.

Determination of ultrasonic velocity in 52 organic liquids

The paper gives determinations of ultrasonic velocities at 7·32 × 106 cycles for 52 organic liquids and water by the method of diffraction of light by ultrasonic waves. It is shown how the velocity depends on chemical constitution.