SEISMIC WAVE STUDIES OVER A HIGH‐SPEED SURFACE LAYER

Geophysics ◽  
1956 ◽  
Vol 21 (2) ◽  
pp. 285-298 ◽  
Author(s):  
Frank Press ◽  
Milton B. Dobrin
Keyword(s):  
Surface Layer ◽  
Surface Waves ◽  
High Speed ◽  
Low Frequency ◽  
Eagle Ford Shale ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Austin Chalk ◽  
Low Pass ◽  
High Frequency Waves

The propagation of compressional, shear, and surface waves was studied along a 3,200 ft profile at a location where a 95‐ft‐thick surface layer of Austin chalk, with a compressional velocity of about 9,900 ft/sec, overlies a 400‐ft section of Eagle Ford shale with a speed of about 6,500 ft/sec. Woodbine sand, with a velocity of about 9,900 ft/sec, underlies the shale. Refracted first arrivals transmitted through the high speed surface layer show an increase of frequency with distance from the shot. A refracted second arrival from the Woodbine decreases in frequency and, after correction for spreading, increases in relative amplitude with distance. This would indicate that the high‐speed surface layer acts as a high‐pass filter for energy transmitted horizontally and as a low‐pass filter for energy transmitted vertically through the layer. Shear waves transmitted through the Austin chalk are also observed. Surface waves consist of two groups of arrivals; a brief train of high‐frequency waves (greater than 20 cps) propagated almost entirely in the surface layer is followed by a short train of low frequency waves. Unlike surface waves in most other localities, the two groups show almost no dispersion. The characteristics of both kinds of waves are interpreted qualitatively in terms of the layering.

Based on the CO2 Gas Shielded Welding Molten Pool Image Edge Detection Algorithm

2013 ◽  
Vol 437 ◽  
pp. 840-844 ◽  
Author(s):  
Xiao Gang Liu ◽  
Bing Zhao
Keyword(s):  
Edge Detection ◽  
Molten Pool ◽  
High Speed ◽  
Vision System ◽  
Detection Algorithm ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Defect Recognition ◽  
Pool Image

This paper use the passive vision system through high-speed camera collects molten pool images; and then according to the frequency domain characteristics of the weld pool image Butterworth low-pass filter; gradient method for image enhancement obtained after pretreatment. Research Roberts, Sobel, Prewitt, Log, Zerocross, and Canny 6 both traditional differential operator edge detection processing results. Through comparison and analysis of choosing threshold for [0.1, 0. Canny operator can get the ideal molten pool edge character, for subsequent welding molten pool defect recognition provides favorable conditions.

scholarly journals Experiments on generation of surface waves by an underwater moving bottom

2015 ◽  
Vol 471 (2178) ◽  
pp. 20150069 ◽  
Author(s):  
Timothée Jamin ◽  
Leonardo Gordillo ◽  
Gerardo Ruiz-Chavarría ◽  
Michael Berhanu ◽  
Eric Falcon
Keyword(s):  
Free Surface ◽  
Surface Waves ◽  
Surface Deformation ◽  
Fluid Layer ◽  
Fluid Velocity ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Spatio Temporal ◽  
Experimental Findings

We report laboratory experiments on surface waves generated in a uniform fluid layer whose bottom undergoes an upward motion. Simultaneous measurements of the free-surface deformation and the fluid velocity field are focused on the role of the bottom kinematics (i.e. its spatio-temporal features) in wave generation. We observe that the fluid layer transfers bottom motion to the free surface as a temporal high-pass filter coupled with a spatial low-pass filter. Both filter effects are often neglected in tsunami warning systems, particularly in real-time forecast. Our results display good agreement with a prevailing linear theory without any parameter fitting. Based on our experimental findings, we provide a simple theoretical approach for modelling the rapid kinematics limit that is applicable even for initially non-flat bottoms: this may be a key step for more realistic varying bathymetry in tsunami scenarios.

A New Capacitance Multiplier Structure with High Multiplication Factor for Ultra-Low-Frequency Filter in Biomedical Applications

2019 ◽  
Vol 29 (07) ◽  
pp. 2050109
Author(s):  
Yan Li ◽  
Yong Liang Li
Keyword(s):  
Biomedical Applications ◽  
Low Frequency ◽  
Multiplication Factor ◽  
Frequency Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Physiological Signal ◽  
Wide Range ◽  
Low Pass ◽  
Capacitance Multiplier

A novel capacitance multiplier is proposed to implement an ultra-low-frequency filter for physiological signal processing in biomedical applications. With the proposed multiplier, a simple first-order low-pass filter achieves a [Formula: see text]3-dB frequency of 33.4[Formula: see text]μHz with a 1-pF capacitance and a 20[Formula: see text]k[Formula: see text] resistance. This corresponds to a multiplication factor of as large as [Formula: see text]. By changing the controlling terminal, the [Formula: see text]3-dB frequency can be tuned in a wide range of 33.4[Formula: see text]μHz–6.3[Formula: see text]kHz.

LC-Resonant and High-Temperature Resistant Acceleration Sensor Based on DSP

2011 ◽  
Vol 105-107 ◽  
pp. 1966-1969
Author(s):  
Tao Guo ◽  
Jie Zhu ◽  
Gui Tang ◽  
Yan Xu
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Space Shuttle ◽  
Digital Signal ◽  
Acceleration Sensor ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Analog To Digital ◽  
Acceleration Sensors ◽  
Low Pass

It is a challenging problem to test the acceleration of the high-speed missiles and space shuttle under high temperature. This paper proposed a design of LC-resonant and high-temperature resistant acceleration sensors about the phenomenon. With the operational amplifier OP4177, it produces the input signal that contents with A/D (Analog to Digital) signal. An eight level low-pass filter MAX291 is used for testing after the signal is regulated. This design mainly uses AD7934 to complete the conversion from analog signals to digital signals. It also recognizes the resonant point of LC acceleration sensor by the DSP （Digital Signal Processing）recognizing program. The acceleration is computed finally by the DSP chip.

Design of the Broadband Standard Signal Generator for Laser Locating System of the Mine Hoisting Container

2013 ◽  
Vol 427-429 ◽  
pp. 2033-2036
Author(s):  
Di Fan ◽  
Yan Gao ◽  
Yue Zhao
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Frequency Standard ◽  
Analog Filters ◽  
Laser Ranging ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Noise Disturbance ◽  
Standard Signal ◽  
Low Pass

As the key junction between the ground and underground, hoisting systems as well as mines themselves are of vital importance to coalmine production. Laser ranging method is studied as a new solution of getting the real-time position directly. Furthermore, multi-scale phase based laser ranging principles are utilized in the system. The paper is aimed to conduct research into the problems existing in standard signal generating while using laser to locating the hoisting container, and to design standard sine generator circuits with DDS technology and DDS devices AD9850 to generate multiple frequency standard signals. In view of the serious noise disturbance in high frequency output, 4-order Chebyshev low-pass filter is designed, by using the integrated analog filters LT 6600-15, to filter the sine signals from AD9850 and to effectively weaken the noise disturbance. The established practical circuits are tested, obtaining trillion level high frequency and low frequency sine signals and fulfilling the requirements for the location system of hoisting containers.

scholarly journals Inductanceless high order low frequency filters for medical applications

2022 ◽  
Vol 12 (2) ◽  
pp. 1299
Author(s):  
Noor Thamer Almalah ◽  
Faris Hasan Aldabbagh
Keyword(s):  
Integrated Circuit ◽  
Low Frequency ◽  
Negative Resistance ◽  
Acceptable Result ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Transconductance Amplifier ◽  
Low Pass ◽  
Minimum Number ◽  
Order Butterworth Filter

<p>In this paper, a designed circuit used for low-frequency filters is implemented and realized the filter is based on frequency-dependent negative resistance (FDNR) as an inductor simulator to substitute the traditional inductance, which is heavy and high cost due to the coil material manufacturing and size area. The simulator is based on an active operation amplifier or operation transconductance amplifier (OTA) that is easy to build in an integrated circuit with a minimum number of components. The third and higher-order Butterworth filter is simulated at low frequency for low pass filter to use in medical instruments and low-frequency applications. The designed circuit is compared with the traditional proportional integral controller enhanced (PIE) and T section ordinary filter. The results with magnitude and phase response were compared and an acceptable result is obtained. The filter can be used for general applications such as medical and other low-frequency filters needed.</p>

A SiGe HBT 6th-Order 10 GHz Inductor-Less Anti-Aliasing Low-Pass Filter for High-Speed ATI Digitizers

2021 ◽  
pp. 1-14
Author(s):  
Francesco Centurelli ◽  
Pietro Monsurro ◽  
Giuseppe Scotti ◽  
Pasquale Tommasino ◽  
Alessandro Trifiletti
Keyword(s):  
High Speed ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Sige Hbt ◽  
Low Pass

TECHNIQUE OF APPLICATION FOR PROCESSING OF LOW PASS FILTER LF SIGNALS

10.12737/7905 ◽  
2015 ◽  
Vol 7 (4) ◽  
pp. 35-38
Author(s):  
Табаков ◽  
Yu. Tabakov ◽  
Лавлинский ◽  
V. Lavlinskiy
Keyword(s):  
Mathematical Model ◽  
Block Diagram ◽  
Low Frequency ◽  
Frequency Signal ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Mathematical Model ◽  
40 Hz

The article includes a block diagram and the mathematical model for low pass filter designed for processing low frequency signal with a frequency of 10-40 Hz in order of eliminate various noises and interference.

Sign in / Sign up

Export Citation Format

Share Document