Development of an Instantaneous Velocity-Vector-Profile Method Using Conventional Ultrasonic Transducers

2021 ◽  
Author(s):  
Dongik Yoon ◽  
Hyun Jin Park ◽  
Tomonori Ihara
Keyword(s):  
Velocity Vector ◽  
Ultrasound Velocity ◽  
Ultrasonic Transducers ◽  
New Method ◽  
Ultrasound Transducers ◽  
Accuracy And Precision ◽  
Conventional Ultrasound ◽  
Measurable Distance ◽  
Profile Technique ◽  
Good Agreement

Abstract The velocity vector profile technique based on an ultrasound pulsed Doppler method can enrich the information of a flow field, however, it has shown a low availability because a new design of special transducers is required for each measurement case. This study proposes a new method of profiling the velocity vectors using conventional ultrasound transducers that are widely supplied to UVP (Ultrasound velocity profile) users. We constructed a configuration of the transducers to minimize the uncertainty of the detection points at the receivers, and a measurable distance was theoretically determined by the configuration. Two feasibility tests were carried out. One was a test for the assessment of the measurable distance, which agreed well with the theoretical distance. The other was the evaluation of the measurement of two-dimensional velocity vectors by the new method and it was performed in a towing tank facility without the velocity fluctuation. From the evaluation, it was confirmed that the measured vectors showed good agreement to the reference values, and their accuracy and precision were competitive compared to previous studies. The developed method was applied to two unsteady flows for demonstrations. The results clarified that the proposed method guarantees high availability and accuracy for the velocity vector profiles.

A new modification of the homotopy perturbation method

2021 ◽  
pp. 095745652199987
Author(s):  
Magaji Yunbunga Adamu ◽  
Peter Ogenyi
Keyword(s):  
Comparative Analysis ◽  
Error Analysis ◽  
Perturbation Method ◽  
Homotopy Perturbation Method ◽  
Nonlinear Oscillators ◽  
Absolute Error ◽  
New Method ◽  
Optimal Analysis ◽  
Homotopy Perturbation ◽  
Accuracy And Precision

This study proposes a new modification of the homotopy perturbation method. A new parameter alpha is introduced into the homotopy equation in order to improve the results and accuracy. An optimal analysis identifies the parameter alpha, aimed at improving the solutions. A comparative analysis of the proposed method reveals that the new method presents results with higher degree of accuracy and precision than the classic homotopy perturbation method. Absolute error analysis shows the convenience of the proposed method, providing much smaller errors. Two examples are presented: Duffing and Van der pol’s nonlinear oscillators to demonstrate the efficiency, accuracy, and applicability of the new method.

scholarly journals 3D phonon microscopy with sub-micron axial-resolution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richard J. Smith ◽  
Fernando Pérez-Cota ◽  
Leonel Marques ◽  
Matt Clark
Keyword(s):  
Signal To Noise Ratio ◽  
Single Cells ◽  
Optical Resolution ◽  
Acquisition Time ◽  
Label Free ◽  
Axial Resolution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Accuracy And Precision ◽  
Good Agreement

AbstractBrillouin light scattering (BLS) is an emerging method for cell imaging and characterisation. It allows elasticity-related contrast, optical resolution and label-free operation. Phonon microscopy detects BLS from laser generated coherent phonon fields to offer an attractive route for imaging since, at GHz frequencies, the phonon wavelength is sub-optical. Using phonon fields to image single cells is challenging as the signal to noise ratio and acquisition time are often poor. However, recent advances in the instrumentation have enabled imaging of fixed and living cells. This work presents the first experimental characterisation of phonon-based axial resolution provided by the response to a sharp edge. The obtained axial resolution is up to 10 times higher than that of the optical system used to take the measurements. Validation of the results are obtained with various polymer objects, which are in good agreement with those obtained using atomic force microscopy. Edge localisation, and hence profilometry, of a phantom boundary is measured with accuracy and precision of approximately 60 nm and 100 nm respectively. Finally, 3D imaging of fixed cells in culture medium is demonstrated.

Simulation and Optimization of Wedge-Shaped Ultrasonic Transducers Using Finite Element Method (FEM)

2013 ◽  
Vol 281 ◽  
pp. 112-115 ◽  
Author(s):  
Dan Jin ◽  
Zhao Hui Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Effect ◽  
Ultrasonic Transducers ◽  
Fe Model ◽  
Limited Size ◽  
Simulation And Optimization ◽  
Ultrasonic Flaw ◽  
Shape And Size ◽  
Good Agreement

Wedge-shaped transducers have been widely used in industry as probes for ultrasonic flowmeters or for ultrasonic flaw detectors. But by now, few studies have focused on the influence to the performance of the wedge-shaped transducers brought by their limited size. In this paper, the effect of the shape and size of wedge-shaped substrates on the whole transducer system is discussed and the shape and size of a transducer (0.5MHz) is optimized to eliminate the influence of the boundary effect by using a 2-D Finite Element (FE) model. Lastly, wedge-shaped transducers have been manufactured for experiment which shows a good agreement with the simulation.

scholarly journals Method for Determining Neutral Wind Velocity Vectors Using Measurements of Internal Gravity Wave Group and Phase Velocities

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 546 ◽  
Author(s):  
Andrey V. Medvedev ◽  
Konstantin G. Ratovsky ◽  
Maxim V. Tolstikov ◽  
Roman V. Vasilyev ◽  
Maxim F. Artamonov
Keyword(s):  
Group Velocity ◽  
Wind Velocity ◽  
Wave Vector ◽  
Velocity Vector ◽  
Internal Gravity Waves ◽  
Vertical Wind ◽  
New Method ◽  
Neutral Wind ◽  
Wind Velocities ◽  
Wind Measurements

This study presents a new method for determining a neutral wind velocity vector. The basis of the method is measurement of the group velocities of internal gravity waves. Using the case of the Boussinesq dispersion relation, we demonstrated the ability to measure a neutral wind velocity vector using the group velocity and wave vector data. An algorithm for obtaining the group velocity vector from the wave vector spectrum is proposed. The new method was tested by comparing the obtained winter wind pattern with wind data from other sources. Testing the new method showed that it is in quantitative agreement with the Fabry–Pérot interferometer wind measurements for zonal and vertical wind velocities. The differences in meridional wind velocities are also discussed here. Of particular interest were the results related to the measurement of vertical wind velocities. We demonstrated that two independent methods gave the presence of vertical wind velocities with amplitude of ~20 m/s. Estimation of vertical wind contribution to plasma drift velocity indicated the importance of vertical wind measurements and the need to take them into account in physical and empirical models of the ionosphere and thermosphere.

A method for determining the CEC and chemical composition of clays via XRF

Clay Minerals ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 717-725 ◽  
Author(s):  
S. Battaglia ◽  
L. Leoni ◽  
F. Sartori
Keyword(s):  
Matrix Effects ◽  
Fluorescence Analysis ◽  
Correction Method ◽  
Exchange Capacity ◽  
New Method ◽  
Chemical Compositions ◽  
Wet Chemistry ◽  
X Ray ◽  
Accuracy And Precision ◽  
Source Clays

AbstractA new method for determining the cation exchange capacity (CEC) of clays is proposed. The method is based on X-ray fluorescence analysis of natural and Ba-exchanged clays following the analytical procedure suggested by Franzini et al. (1975). This procedure, which utilizes powder pellets and is based on a full matrix correction method, is frequently applied in Earth Sciences laboratories for the routine analysis of minerals and rocks. For the analysis of Ba-exchanged clays, Franzini's procedure has been modified slightly to account for the contribution of Ba to matrix effects.The new method, which furnishes both the CEC and the chemical compositions of the whole natural clay samples, has been tested on the eight ‘Source Clays’ of The Clay Minerals Society. The results compare well with data reported in the literature and confirm the accuracy and precision of the method and make it a valid alternative to techniques based on wet chemistry, execution of which is usually more time-consuming and which often requires greater analytical skill.

A New Method to Assess Ductility of CFT Box Columns with Binding Bars under Axial Compression

2012 ◽  
Vol 446-449 ◽  
pp. 78-81 ◽  
Author(s):  
Yue Ling Long ◽  
Jian Cai
Keyword(s):  
Experimental Data ◽  
Axial Compression ◽  
Material Properties ◽  
New Method ◽  
Box Columns ◽  
Good Agreement

A new method based on material properties instead of experimental data was proposed to assess the ductility of concrete-filled steel box columns with binding bars and those without binding bars. Comparison between ductility coefficients based on experimental data and the calculated values by the proposed method shows good agreement.

Evaluation of polydispersity index Mw/Mn by quasielastic light scattering

1987 ◽  
Vol 52 (5) ◽  
pp. 1235-1245 ◽  
Author(s):  
Petr Štěpánek ◽  
Zdeněk Tuzar ◽  
Čestmír Koňák
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Decay Time ◽  
Sampling Time ◽  
Polydispersity Index ◽  
New Method ◽  
Molecular Weights ◽  
Quasielastic Light Scattering ◽  
Good Agreement

The response of quasielastic light scattering to the polydispersity of scattering objects has been investigated. A new method of the polydispersity index determination has been suggested, suitable for the range 1.02 ⪬ Mw/Mn ⪬ 2.0 and consisting in the measurement of the dependence of the apparent decay time on the correlator sampling time. The polydispersity index can be determined by comparing these dependences with the theoretical ones obtained using correlation curves simulated for various values of the polydispersity index, assuming lognormal and Schulz-Zimm distributions of molecular weights. The test measurements on polystyrene standards having molecular weights in the range 9 103 – 20.6 106 give polydispersity index values Mw/Mn that are in a good agreement with those given by the manufacturer. The polydispersity index for polystyrene having the molecular weight Mw = 20.6 106 thus determined was Mw/Mn = 1.35.

X-Ray Fluorescence Minor- and Trace-Element Analyses Silicate Rocks in the Presence of Large Interelement Effects

1977 ◽  
Vol 21 ◽  
pp. 75-88
Author(s):  
B. S. King ◽  
L. F. Espos ◽  
B. P. Fabbi
Keyword(s):  
Matrix Effects ◽  
Dilution Method ◽  
Regression Equations ◽  
X Ray ◽  
Geological Materials ◽  
Accuracy And Precision ◽  
Binder Ratio ◽  
Silicate Rocks ◽  
Good Agreement

An X-ray fluorescence (XRF) method has been devised for the rapid quantitative determination of 16 minor and trace elements in geological materials. This method, a modification of a direct dilution method (1, 2, 3), uses a sample-to-binder ratio of 85:15 for sample preparation. Pellets prepared by this method are durable and do not deteriorate rapidly when exposed to high X-ray irradiation. Interferences and matrix effects are successfully corrected in actual analyses by employment of multiple linear regression equations.Accuracy and precision have been improved over the method previously used in this laboratory. Detection limits have been lowered for Zn, Rb, Y and Zn approximately by the factor of 2. When interelement corrections are made, the XRF values are found to be in good agreement with the preferred chemical values for the 19 international silicate-rock standards.

A New Method for Measuring Thermal Contact Conductance: Experimental Technique and Results

2008 ◽  
Author(s):  
Simon Woodland ◽  
Andrew D. Crocombe ◽  
John W. Chew ◽  
Stephen J. Mills
Keyword(s):  
Thermal Contact ◽  
New Method ◽  
Thermal Contact Conductance ◽  
Metal Working ◽  
Loading History ◽  
Test Rig ◽  
Contact Conductance ◽  
Pressure Surface ◽  
Surface Flatness ◽  
Good Agreement

Thermal contact conductance (TCC) is used to characterise heat transfer across interfaces in contact. It is important in thermal modelling of turbomachinery components and finds many other applications in the aerospace, microelectronic, automotive and metal working industries. A new method for measuring TCC is described and demonstrated. A test rig is formed from an instrumented split tube with washers in-between and loading applied in controlled conditions. The experimental method and data analysis is described, and the effect on thermal contact conductance of parameters such as contact pressure, surface roughness, surface flatness and loading history is investigated. The results of these tests are compared to those in the available literature and good agreement of trends is found. However, the tests conducted to measure the effect of load cycling on TCC have found that the TCC continues to increase beyond 20 or so load cycles, contrary to some results in the literature.

Use of Scattered Secondary Target Radiation in EDXRF Analysis: A Fundamental-Parameter Method for Matrix Correction

1986 ◽  
Vol 30 ◽  
pp. 165-174 ◽  
Author(s):  
Tom O'Reilly ◽  
Bi-Shia W. King
Keyword(s):  
Atomic Number ◽  
Light Element ◽  
Parameter Method ◽  
Fundamental Parameter ◽  
Accuracy And Precision ◽  
Edxrf Analysis ◽  
The Mean ◽  
Scatter Intensity ◽  
Fundamental Parameter Method ◽  
Good Agreement

AbstractA new fundamental-parameter program has been developed which corrects for light element absorption based on the mean atomic number of the sample. The mean atomic number, in turn, is determined from the Compton/Rayleigh scatter intensity ratio. The program is quite flexible with regard to the number and the type of standards which may be used. The accuracy and precision of the method has been evaluated with several geological and biological standards. The results are in good agreement with those obtained by some other methods (CEMAS, XRF-11).

Sign in / Sign up

Export Citation Format

Share Document