scholarly journals Design of unidirectional acoustic probes with flexible directivity patterns using two acoustic particle velocity sensors

2018 ◽  
Vol 144 (1) ◽  
pp. EL13-EL19 ◽  
Author(s):  
Yong Wang ◽  
Yixin Yang ◽  
Shiduo Yu
Keyword(s):  
Particle Velocity ◽  
Directivity Patterns

Particle velocity measurement in powder gas jets of coaxial powder nozzles for laser material deposition

2021 ◽  
Vol 33 (1) ◽  
pp. 012019
Author(s):  
Jonathan Schaible ◽  
Luis Andrea Hau ◽  
David Weber ◽  
Thomas Schopphoven ◽  
Constantin Häfner ◽  
...  
Keyword(s):  
Particle Velocity ◽  
Velocity Measurement ◽  
Laser Material ◽  
Gas Jets ◽  
Material Deposition ◽  
Particle Velocity Measurement

Analysis of Spectral Characteristics of Sound Waves Scattered from a Cracked Cylindrical Elastic Shell Filled with a Viscous Fluid

2013 ◽  
Vol 38 (3) ◽  
pp. 335-350 ◽  
Author(s):  
Olexa Piddubniak ◽  
Nadia Piddubniak
Keyword(s):  
Viscous Fluid ◽  
Shell Theory ◽  
Elastic Shell ◽  
Spectral Characteristics ◽  
Steel Shell ◽  
Sound Waves ◽  
Thin Cylindrical Shell ◽  
Shell Surface ◽  
Theory Approximation ◽  
Directivity Patterns

Abstract The scattering of plane steady-state sound waves from a viscous fluid-filled thin cylindrical shell weak- ened by a long linear slit and submerged in an ideal fluid is studied. For the description of vibrations of elastic objects the Kirchhoff-Love shell-theory approximation is used. An exact solution of this problem is obtained in the form of series with cylindrical harmonics. The numerical analysis is carried out for a steel shell filled with oil and immersed in seawater. The modules and phases of the scattering amplitudes versus the dimensionless wavenumber of the incident sound wave as well as directivity patterns of the scattered field are investigated taking into consideration the orientation of the slit on the elastic shell surface. The plots obtained show a considerable influence of the slit and viscous fluid filler on the diffraction process.

scholarly journals Research of the Technical Seismicity Due to Blasting Works in Quarries and Their Impact on the Environment and Population

2021 ◽  
Vol 11 (5) ◽  
pp. 2118
Author(s):  
Jan Feher ◽  
Jozef Cambal ◽  
Blazej Pandula ◽  
Julian Kondela ◽  
Marian Sofranko ◽  
...  
Keyword(s):  
Particle Velocity ◽  
Normative Values ◽  
Internal Environment ◽  
Negative Effects ◽  
Vibration Acceleration ◽  
Limit Values ◽  
Vibration Intensity ◽  
Timing Interval ◽  
Millisecond Timing ◽  
The Impact

Vibrations caused by blasting works have an impact not only on buildings but also the internal environment of the buildings. If these buildings are situated in the surroundings of quarries, the citizens can perceive these vibrations negatively. By applying an appropriate millisecond timing interval, it is possible to lower the intensity of vibrations to the levels that the citizens will not perceive as negative effects inside the buildings. The limit values for this vibration intensity have not been defined to date. For the protection of the building from the vibrations, normative values of the particle velocity and frequency were determined. Hygienic standards for the inhabitants of the housing were applied, which assessed the impact of the vibration on humans through the measurement of the vibration acceleration in the housing. In this article, the results of the research carried out in Trebejov Quarry are presented. The experimental blasts carried out in Trebejov Quarry proved that the reduction in the vibration intensity under the value 2 mm.s−1 led to the satisfaction of the inhabitants.

scholarly journals Prediction of Peak Particle Velocity Caused by Blasting through the Combinations of Boosted-CHAID and SVM Models with Various Kernels

2021 ◽  
Vol 11 (8) ◽  
pp. 3705
Author(s):  
Jie Zeng ◽  
Panayiotis C. Roussis ◽  
Ahmed Salih Mohammed ◽  
Chrysanthos Maraveas ◽  
Seyed Alireza Fatemi ◽  
...  
Keyword(s):  
Radial Basis Function ◽  
Particle Velocity ◽  
Basis Function ◽  
Absolute Error ◽  
Peak Particle Velocity ◽  
Support Vector ◽  
Effective Parameters ◽  
Experimental Database ◽  
Interaction Detection ◽  
Radial Basis

This research examines the feasibility of hybridizing boosted Chi-Squared Automatic Interaction Detection (CHAID) with different kernels of support vector machine (SVM) techniques for the prediction of the peak particle velocity (PPV) induced by quarry blasting. To achieve this objective, a boosting-CHAID technique was applied to a big experimental database comprising six input variables. The technique identified four input parameters (distance from blast-face, stemming length, powder factor, and maximum charge per delay) as the most significant parameters affecting the prediction accuracy and utilized them to propose the SVM models with various kernels. The kernel types used in this study include radial basis function, polynomial, sigmoid, and linear. Several criteria, including mean absolute error (MAE), correlation coefficient (R), and gains, were calculated to evaluate the developed models’ accuracy and applicability. In addition, a simple ranking system was used to evaluate the models’ performance systematically. The performance of the R and MAE index of the radial basis function kernel of SVM in training and testing phases, respectively, confirm the high capability of this SVM kernel in predicting PPV values. This study successfully demonstrates that a combination of boosting-CHAID and SVM models can identify and predict with a high level of accuracy the most effective parameters affecting PPV values.

Penetration Dynamics of Solid Particles into Liquids High-Speed Experimental Results and Modelling

2005 ◽  
Vol 473-474 ◽  
pp. 429-434 ◽  
Author(s):  
Olga Verezub ◽  
György Kaptay ◽  
Tomiharu Matsushita ◽  
Kusuhiro Mukai
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Aqueous Solutions ◽  
Particle Velocity ◽  
Weber Number ◽  
High Speed ◽  
Solid Particles ◽  
Bulk Liquid ◽  
Distilled Water ◽  
Critical Weber Number

Penetration of model solid particles (polymer, teflon, nylon, alumina) into transparent model liquids (distilled water and aqueous solutions of KI) were recorded by a high speed (500 frames per second) camera, while the particles were dropped from different heights vertically on the still surface of the liquids. In all cases a cavity has been found to form behind the solid particle, penetrating into the liquid. For each particle/liquid combination the critical dropping height has been measured, above which the particle was able to penetrate into the bulk liquid. Based on this, the critical impact particle velocity, and also the critical Weber number of penetration have been established. The critical Weber number of penetration was modelled as a function of the contact angle, particle size and the ratio of the density of solid particles to the density of the liquid.

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