An automated apparatus for ultrasound velocity measurements improving the pulse‐echo‐overlap method to a precision better than 0.5 ppm in liquids

1-Butanol can be considered as a good fuel additive, which can be used at high pressures. Therefore, the knowledge of high-pressure thermophysical properties is crucial for this application. In this paper, new experimental data on the speed of sound in 1-butanol in the temperature range from 293 to 318 K and at pressures up to 101 MPa are reported. The speed of sound at a frequency of 2 MHz was measured at atmospheric and high pressures using two measuring sets operating on the principle of the pulse–echo–overlap method. The measurement uncertainties were estimated to be better than ±0.5 m·s−1 and ± 1 m·s−1 at atmospheric and high pressures, respectively. Additionally, the density was measured under atmospheric pressure in the temperature range from 293 to 318 K using a vibrating tube densimeter Anton Paar DMA 5000. Using the experimental results, the density and isobaric and isochoric heat capacities, isentropic and isothermal compressibilities, isobaric thermal expansion, and internal pressure were calculated at temperatures from 293 to 318 K and at pressures up to 100 MPa.

Download Full-text

Ultrasonic Velocity Measurements of Engineering Plastic Cores by Pulse-echo-overlap Method Using Cross-correlation

Geophysics and Geophysical Exploration ◽

10.7582/gge.2013.16.3.171 ◽

2013 ◽

Vol 16 (3) ◽

pp. 171-179

Author(s):

Sang Kyu Lee ◽

Tae Jong Lee ◽

Hyoung Chan Kim

Keyword(s):

Ultrasonic Velocity ◽

Cross Correlation ◽

Velocity Measurements ◽

Engineering Plastic ◽

Overlap Method ◽

Pulse Echo

Download Full-text

Optimising the Transfer Alignment of Weapon INS

Journal of Navigation ◽

10.1017/s0373463303002261 ◽

2003 ◽

Vol 56 (2) ◽

pp. 323-335 ◽

Cited By ~ 31

Author(s):

Paul D. Groves

Keyword(s):

Inertial Sensor ◽

Integrated Navigation ◽

Velocity Measurements ◽

Transfer Alignment ◽

Navigation Solution ◽

Alignment Technique ◽

Alignment Process ◽

Using Data ◽

Design Options ◽

Better Than

Transfer alignment is the process of initialising and calibrating a weapon INS using data from the host aircraft's navigation system. To determine which transfer alignment technique performs best, different design options have been assessed, supported by simulation work. The dependence of transfer alignment performance on environmental factors, such as manoeuvres, alignment duration, lever arm and inertial sensor quality has also been studied. ‘Rapid’ alignment, using attitude as well as velocity measurements was found to perform better than ‘conventional’ techniques using only velocity. Innovative developments include the estimation of additional acceleration and gyro states and estimation of force dependent relative orientation, which has enabled robust alignment using wing rock manoeuvres, which do not require the pilot to change trajectory. Transfer alignment has been verified in real-time by flight trials on a Tornado aircraft. In addition, techniques have been developed to prevent transients in the aircraft integrated navigation solution following GPS re-acquisition after an outage of several minutes from disrupting the transfer alignment process.

Download Full-text

Mass determination of the 1:3:5 near-resonant planets transiting GJ 9827 (K2-135)

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832872 ◽

2018 ◽

Vol 618 ◽

pp. A116 ◽

Cited By ~ 13

Author(s):

J. Prieto-Arranz ◽

E. Palle ◽

D. Gandolfi ◽

O. Barragán ◽

E. W. Guenther ◽

...

Keyword(s):

Planetary System ◽

Initial Conditions ◽

Dynamical Evolution ◽

Space Mission ◽

Mass Determination ◽

Velocity Measurements ◽

Orbital Periods ◽

The Masses ◽

Better Than

Context. Multiplanet systems are excellent laboratories to test planet formation models as all planets are formed under the same initial conditions. In this context, systems transiting bright stars can play a key role, since planetary masses, radii, and bulk densities can be measured. Aims. GJ 9827 (K2-135) has recently been found to host a tightly packed system consisting of three transiting small planets whose orbital periods of 1.2, 3.6, and 6.2 days are near the 1:3:5 ratio. GJ 9827 hosts the nearest planetary system (~30 pc) detected by NASA’s Kepler or K2 space mission. Its brightness (V = 10.35 mag) makes the star an ideal target for detailed studies of the properties of its planets. Methods. Combining the K2 photometry with high-precision radial-velocity measurements gathered with the FIES, HARPS, and HARPS-N spectrographs we revised the system parameters and derive the masses of the three planets. Results. We find that GJ 9827 b has a mass of Mb = 3.69−0.46+0.48 M⊕ and a radius of Rb = 1.58−0.13+0.14 R⊕, yielding a mean density of ρb = 5.11−1.27+1.74 g cm−3. GJ 9827 c has a mass of Mc = 1.45−0.57+0.58 M⊕, radius of Rc = 1.24−0.11+0.11 R⊕, and a mean density of ρc = 4.13−1.77+2.31 g cm−3. For GJ 9827 d, we derive Md = 1.45−0.57+0.58 M⊕, Rd = 1.24−0.11+0.11 R⊕, and ρd = 1.51−0.53+0.71 g cm−3. Conclusions. GJ 9827 is one of the few known transiting planetary systems for which the masses of all planets have been determined with a precision better than 30%. This system is particularly interesting because all three planets are close to the limit between super-Earths and sub-Neptunes. The planetary bulk compositions are compatible with a scenario where all three planets formed with similar core and atmosphere compositions, and we speculate that while GJ 9827 b and GJ 9827 c lost their atmospheric envelopes, GJ 9827 d maintained its primordial atmosphere, owing to the much lower stellarirradiation. This makes GJ 9827 one of the very few systems where the dynamical evolution and the atmosphericescape can be studied in detail for all planets, helping us to understand how compact systems form and evolve.

Download Full-text

Ultrasound Velocity Imaging by a Pulse-Echo Technique

Acoustical Imaging ◽

10.1007/978-1-4615-3370-2_75 ◽

1992 ◽

pp. 475-480 ◽

Cited By ~ 1

Author(s):

W. C. A. Pereira ◽

S. Leeman ◽

J. C. Machado

Keyword(s):

Ultrasound Velocity ◽

Velocity Imaging ◽

Pulse Echo

Download Full-text

THE STUDY OF THE INFLUENCE OF X-RAY IRRADIATION ON DISLOCATION CHARACTERISTICS IN LiF CRYSTALS

10.46813/2021-135-021 ◽

2021 ◽

pp. 21-25

Author(s):

О.M. Petchenko ◽

G.О. Petchenko ◽

S.M. Boiko ◽

А.S. Litvinenko

Keyword(s):

Irradiation Time ◽

Acoustic Pulse ◽

Residual Deformation ◽

Ultrasound Velocity ◽

Wide Frequency Range ◽

Effective Length ◽

Acoustic Characteristics ◽

Frequency Branch ◽

Attenuation Mechanism ◽

Pulse Echo

The dependences of the absorption α and the ultrasound velocity in LiF single crystals with residual deformation ε = 0.65% at 300 K in the range of radiation doses 0...1057 R were studied using the acoustic pulse echo method at a frequency of 7.5 MHz. Based on the results of measurements of the acoustic characteristics, the absolute values of the parameters of the dislocation structure – the average effective length of the dislocation loop L and the dislocation density Λ and their dependences on the irradiation time are determined. The calculated characteristics are compared with the previously obtained results for the high-frequency branch of the damped dislocation resonance and using the selective etching method. The revealed noticeable discrepancy in the values of these parameters is explained by the impossibility of describing a single attenuation mechanism for acoustic measurements carried out in a wide frequency range.

Download Full-text