scholarly journals Digital Processing of Seismic Data from Open-Pit Mining Blasts

2021 ◽  
Vol 11 (1) ◽  
pp. 383
Author(s):  
Natalia Koteleva ◽  
Ilia Frenkel
Keyword(s):  
Experimental Data ◽  
Wavelet Analysis ◽  
Correlation Dimension ◽  
Low Frequency ◽  
Digital Processing ◽  
Dominant Frequency ◽  
Open Pit ◽  
Open Pit Mining ◽  
Frequency Range ◽  
Amplitude Dependency

This article describes an approach of mathematical processing of signals (seismograms) from five blasthole charges from experimental blasting, each 3 m deep, with equal explosive weight (1 kg), and equidistant (3 m) from one other. The seismic explosive waves were measured at a 13 to 25 m distance. This article provides spectral analysis, wavelet analysis, and fractal analysis results. It defines the dependence of dominant frequency and amplitude on the distance to the blast center. According to the experimental data, the dominant frequency is calculated as y = 1.0262x0.2622 and the amplitude dependency as y = 18.139x−2.276. Furthermore, the analysis shows that 80% of the entire signal is concentrated in half the area of frequency range, i.e., the low frequency zone is of the most interest. This research defines the dependence of distance on the energy value of signal wavelet analysis. It is demonstrated that, according to the experimental data, the 12th frequency range is closely correlated with the distance values. This article gives the definitions of entropy, correlation dimension, and predictability time. This experiment shows that entropy and correlation dimension decrease but predictability time increases when the distance to the blast center increases. This article also describes the method for determining optimal drilling and blasting parameters, and concludes with the possibility of applying the analytical results to predicting and enhancing drilling and blasting operations.

Detection of Vortex Frequency in Gas Flow with Ultrasound

2005 ◽  
Vol 295-296 ◽  
pp. 515-520
Author(s):  
Volker Hans ◽  
C. Filips
Keyword(s):  
Signal Processing ◽  
Carrier Frequency ◽  
Gas Flow ◽  
Bluff Body ◽  
Low Frequency ◽  
Digital Processing ◽  
Simple Relation ◽  
Frequency Range ◽  
Body Dimension ◽  
Integer Multiple

The coincidence of vortices generated by a bluff body in a gaseous flow (Karman vortex street) with an ultrasonic beam crossing these vortices raises a lot of questions concerning physics and signal processing. The ultrasonic signal will be complex modulated. The spectrum of the resulted signal shows the carrier frequency of ultrasound and two narrow sidebands with the information about the modulation. For further signal processing the carrier frequency must be filtered. The carrier frequency can be shifted to zero by digital processing and undersampling the signal by an integer multiple. Then the sideband with its low frequency range can be analysed. The real and imaginary parts of the signal can be determined by sampling the signal shifted by 90 degrees (Hilbert transform). Even the 90 degree shifted angle can be measured by undersampling. The sensitivity of the vortex meter depends on the bluff body size. A simple relation between the bluff body dimension and the sensitivity, the vortex frequency, respectively, is shown.

Collision–induced absorption in gaseous methane at low temperatures

1986 ◽  
Vol 64 (7) ◽  
pp. 763-767 ◽  
Author(s):  
I. R. Dagg ◽  
A. Anderson ◽  
S. Yan ◽  
W. Smith ◽  
C. G. Joslin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Low Temperatures ◽  
Low Frequency ◽  
Frequency Region ◽  
Experimental Results ◽  
Published Data ◽  
Frequency Range ◽  
Simple Method ◽  
Induced Absorption ◽  
Good Agreement

A recently developed theory for collision-induced absorption in methane is compared with experimental results over a wider spectral range and at lower temperatures than previously reported. The present experimental results covering the frequency range below 400 cm−1 exhibit good agreement with other recently published data. The theory shows excellent agreement with experiment in the low-frequency region below approximately 200 cm−1 but underestimates the experimental data somewhat at higher frequencies. Possible theoretical reasons for this discrepancy are given. The theory represents a simple method of obtaining a good estimate of the collision-induced absorption spectra of methane in this frequency region and for extrapolating to lower temperatures for which experimentation is not feasible. In addition, the moments α1 and γ1are compared with earlier determinations and indicate good agreement with the previously obtained values for the octupole and hexadecapole moments of methane.

scholarly journals Vibrational Cooling After Photo Isomerisation: First Application of a Novel Intramolecular Thermometer

1999 ◽  
Vol 19 (1-4) ◽  
pp. 45-49 ◽  
Author(s):  
P. Hamm ◽  
S. Ohline ◽  
M. Zurek ◽  
T. Röschinger
Keyword(s):  
Experimental Data ◽  
Schiff Base ◽  
Time Resolution ◽  
High Frequency ◽  
Low Frequency ◽  
Frequency Range ◽  
Frequency Shifts ◽  
Absorption Change ◽  
Vibrational System ◽  
Anharmonic Coupling

Femtosecond VIS-pump-IR-probe experiments (time resolution: 300fs, detectable absorption change: 5.10-5 , frequency range: 1000–1800 cm-1) were applied to the ultrafast photo isomerisation of azobenzene and the protonated Schiff base of retinal. The energy of the pump photon heats the vibrational system of the molecule, leading to pronounced anharmonic frequency shifts which are dominated by the anharmonic coupling between the investigated high frequency modes to hot low frequency modes. A model taking into account this intramolecular anharmonicity and assuming a well defined intramolecular temperature gives a good fit of the experimental data.

scholarly journals Structural Performance Assessment Based on Statistical and Wavelet Analysis of Acceleration Measurements of a Building during an Earthquake

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Mosbeh R. Kaloop ◽  
Jong Wan Hu ◽  
Mohamed A. Sayed ◽  
Jiyoung Seong
Keyword(s):  
Wavelet Analysis ◽  
Health Monitoring ◽  
Energy Content ◽  
Dominant Frequency ◽  
Wavelet Spectrum ◽  
Structural Performance ◽  
Frequency Range ◽  
Recording Point ◽  
National University ◽  
Seoul National University

This study introduces the analysis of structural health monitoring (SHM) system based on acceleration measurements during an earthquake. The SHM system is applied to assess the performance investigation of the administration building in Seoul National University of Education, South Korea. The statistical and wavelet analysis methods are applied to investigate and assess the performance of the building during an earthquake shaking which took place on March 31, 2014. The results indicate that (1) the acceleration, displacement, and torsional responses of the roof recording point on the top floor of the building are more dominant in theXdirection; (2) the rotation of the building has occurred at the base recording point; (3) 95% of the energy content of the building response is shown in the dominant frequency range (6.25–25 Hz); (4) the wavelet spectrum illustrates that the roof vibration is more obvious and dominant during the shaking; and (5) the wavelet spectrum reveals the elasticity responses of the structure during the earthquake shaking.

Identification of Energy Dissipation in Structural Joints by Means of the Energy Flow Analysis

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
S. S. Gómez ◽  
A. Metrikine ◽  
B. Carboni ◽  
W. Lacarbonara
Keyword(s):  
Experimental Data ◽  
Energy Dissipation ◽  
Energy Flow ◽  
Degrees Of Freedom ◽  
Flow Analysis ◽  
Low Frequency ◽  
Frequency Range ◽  
Energy Flow Analysis ◽  
Damping Matrix ◽  
Good Agreement

In this paper, identification of energy dissipation in the joints of a lab-scale structure is accomplished. The identification is carried out by means of an energy flow analysis and experimental data. The devised procedure enables to formulate an energy balance in the vicinity of the joints to obtain local energy dissipation. In this paper, a damping matrix based on the locally identified damping coefficients is formulated. The formulated damping matrix is later used in a five-degrees-of-freedom (5DOF) system for validation. The results obtained with the proposed method are in good agreement with the experimental data, especially in the low frequency range.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

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