Electromagnetic methods (low frequency)

2008 ◽  
pp. 243-254
Keyword(s):  
Low Frequency ◽  
Electromagnetic Methods

scholarly journals Fracture zones detection for groundwater exploration integrating Resistivity Profiling and Very Low Frequency electromagnetic methods (Errachidia basin, Morocco)

2019 ◽  
Vol 49 (2) ◽  
pp. 181-194
Author(s):  
Youssef Ait Bahammou ◽  
Ahmed Benamara ◽  
Abdellah Ammar ◽  
Ibrahim Dakir
Keyword(s):  
Low Frequency ◽  
Groundwater Exploration ◽  
Depth Range ◽  
Fracture Zones ◽  
Real Component ◽  
Very Low Frequency ◽  
Resistivity Measurements ◽  
Electromagnetic Methods ◽  
Groundwater Supply ◽  
Resistivity Profiling

Abstract Resistivity Profiling and Very Low Frequency (VLF) electromagnetic methods were introduced to study fracture zones detection in Zaouia Jdida locality, within the Errachidia basin. The Horizontal Profiling was conducted in Wenner-α array, with AB = 300 m and profile lines oriented NW–SE and NE–SW. The resistivity measurements were taken using MAE advanced geophysics instruments. The VLF profiles were implanted with the length reaches 1000 m and profile lines oriented in NE–SW direction. The VLF measurements were collected using T-VLF iris instrument and the data filtering was done using KHFFILT software. Two filters, Karous-Hjelt and Fraser, were applied to the real component of the secondary electromagnetic field. The qualitative interpretation of resistivity results, showed the presence of subsurface targets; fracture zones were detected at 70m, 240m and 450m positions along the profile P1, at 180m, 340m and 450m positions from the profile P2. The semi-quantitative interpretation of VLF results revealed the presence of two principal fracture zones at L3 and L5 locations, oriented NW–SE, at a depth range of 30 m to 60 m. The VLF anomaly observed at L3 location is confirmed by the resistivity measurements from the profile P1 (at 70m station). The identified fractures represent the potential zones for groundwater supply and then will have an implication on storage and movement of groundwater in the prospect area.

scholarly journals EVALUATION OF STRESS IN STEEL STRUCTURES USING ELECTROMAGNETIC METHODS BASED ON UTILIZATION OF MICROSTRIP ANTENNA SENSOR AND MONITORING OF AC MAGNETIZATION PROCESS

2016 ◽  
Vol 6 (4) ◽  
pp. 32-36 ◽  
Author(s):  
Przemysław Łopato ◽  
Grzegorz Psuj ◽  
Michał Herbko ◽  
Michał Maciusowicz
Keyword(s):  
Plastic Deformation ◽  
High Frequency ◽  
Magnetic Hysteresis ◽  
Low Frequency ◽  
Steel Structures ◽  
Magnetic Hysteresis Loop ◽  
Magnetization Process ◽  
Frequency Range ◽  
Frequency Method ◽  
Electromagnetic Methods

In this paper the results of utilization of electromagnetic methods operating in low and high frequency range for evaluation of stress state and plastic deformation in steel elements are presented. In low frequency range Barkhausen noise and magnetic hysteresis loop method for evaluation of stress level and growth of plastic deformation changes were utilized. The methods allow to monitor parameters related to magnetization process under AC filed. Additionally in this paper the possibility of utilization of high frequency method for estimation of deformation extent (i.e. elongation) caused by stress will be presented. In this experiment the frequency response (the reflection coefficient S11) is measured. The strong relation of antennas resonant frequency to patch dimensions is utilized in order to obtain information about deformation of the sample.

scholarly journals High resolution electromagnetic methods and low frequency dispersion of rock conductivity

1999 ◽  
Vol 42 (4) ◽  
Author(s):  
B. S. Svetov ◽  
V. V. Ageev
Keyword(s):  
High Resolution ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Electromagnetic Methods ◽  
Near Zone ◽  
Vertical Magnetic Dipole ◽  
Time Domains ◽  
Debye Formula ◽  
Wave Phenomena ◽  
Depth Of Investigation

The influence of frequency dispersion of conductivity (induced polarization) of rocks on the results of electromagnetic (EM) sounding was studied on the basis of calculation of electric field of vertical magnetic dipole above horizontally layered polarizable sections. Frequency dispersion was approximated by the Debye formula. Polarizable homogeneous halfspace, two, three and multilayered sections were analyzed in frequency and time domains. The calculations for different values of chargeability and time constants of polarization were performed. In the far zone of a source, the IP of rocks led to quasi-wave phenomena. They produced rapid fluctuations of frequency and transient sounding curves (interference phenomena, multireflections in polarizable layers). In the case of transient sounding in the near zone of a source quasistatic distortions prevailed, caused by the counter electromotive force arising in polarizable layers which may lead to strong changes in transient curves. In some cases quasiwave and quasistatic phenomena made EM sounding curves non-interpretable in the class of quasistationary curves over non-dispersive sections. On the other hand, they could increase the resolution and depth of investigation of EM sounding. This was confirmed by an experience of "high-resolution" electroprospecting in Russia. The problem of interpretation of EM sounding data in polarizable sections is nonunique. To achieve uniqueness it is probably necessary to complement them by soundings of other type.

scholarly journals The Application of Geophysical Methods in Identification of Subsurface Fractures in The Vicinity of a Poor Performance Percolation Tank

2021 ◽  
pp. 386-388
Author(s):  
Irshad S Shaikh ◽  
Dr. Aayyed Haffiyuddin Badurrudin ◽  
Dr. P. L. Salve
Keyword(s):  
Geophysical Methods ◽  
Low Frequency ◽  
Poor Performance ◽  
Early Summer ◽  
Water Users ◽  
Electromagnetic Methods ◽  
Short Period ◽  
Subsurface Fractures ◽  
Area Of Influence ◽  
The Village

Percolation tanks are constructed to conserve the rainwater in large quantities and allow more infiltration in its area of influence. Sometimes due to heavy fracture concentration/thick weathered zone, the water in percolation tank migrates fast in short period and tank becomes dry, which leads to early scarcity conditions. The village karkatta of taluka and district Latur is one such village, where water is provided by constructing two wells in the vicinity of percolation tank. The water level in the percolation tank depletes fast and the tank becomes dry in early summer. Also one cement nala bandhara was constructed in the downstream of the nala. The village is funded by UNICEF to implement MUS (Multiple Water Users) project. The area is surveyed by applying both electrical resistivity methods and low frequency electromagnetic methods in submergence of tank as well as in the downstream of percolation tank. The studies reveal that the leakages are due to thick vesicular basalt followed by fractured massive basalt. Suitable remedial measures are recommended to slow down the subsurface flow so as to improve the performance of the percolation tank.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

Lectin Binding to Human Breast Tumor Cells

1976 ◽  
Vol 34 ◽  
pp. 34-35
Author(s):  
Robert E. Nordquist ◽  
J. Hill Anglin ◽  
Michael P. Lerner
Keyword(s):  
Carcinoma Cell ◽  
Ricinus Communis ◽  
Lectin Binding ◽  
Low Frequency ◽  
Breast Carcinoma Cell Line ◽  
Human Breast ◽  
Human Breast Tumor ◽  
Duct Carcinoma ◽  
Specific Antigens ◽  
Ricin Agglutinin

A human breast carcinoma cell line (BOT-2) was derived from an infiltrating duct carcinoma (1). These cells were shown to have antigens that selectively bound antibodies from breast cancer patient sera (2). Furthermore, these tumor specific antigens could be removed from the living cells by low frequency sonication and have been partially characterized (3). These proteins have been shown to be around 100,000 MW and contain approximately 6% hexose and hexosamines. However, only the hexosamines appear to be available for lectin binding. This study was designed to use Concanavalin A (Con A) and Ricinus Communis (Ricin) agglutinin for the topagraphical localization of D-mannopyranosyl or glucopyranosyl and D-galactopyranosyl or DN- acetyl glactopyranosyl configurations on BOT-2 cell surfaces.

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