INDUCED POLARIZATION: A METHOD OF GEOPHYSICAL PROSPECTING

Geophysics ◽  
1953 ◽  
Vol 18 (3) ◽  
pp. 636-661 ◽  
Author(s):  
D. F. Bleil
Keyword(s):  
Laboratory Experiments ◽  
Field Measurements ◽  
Potential Drop ◽  
Induced Polarization ◽  
Polarization Potential ◽  
The Body ◽  
Chemical Action ◽  
Electrically Conducting ◽  
Point Electrode ◽  
Metallic Body

Laboratory experiments have shown certain fundamental relationships concerning the induction of a polarization potential on a metallic body in an electrolyte. The potential induced is a linear function of the potential drop across the body in the energizing field up to a saturation potential of 1.2 volts. Diffusion of ions and chemical action are the predominant factors which determine the rate of growth or decay of the polarization potential. Polarization occurs only at the boundaries of electrically conducting minerals. The results of the laboratory experiments provide an explanation of the induced polarization potential of a homogeneous, uniformly mineralized earth. This potential falls off as 1/r from a point electrode. Induced polarization susceptibility is defined and a method of analyzing field data is described. Field measurements over two mineralized zones (pyrrhotite and magnetite) substantiate the theory as developed.

scholarly journals ANALISIS KADAR KLORIN PADA TEH CELUP BERDASARKAN WAKTU SEDUHAN

2014 ◽  
Vol 1 (1) ◽  
pp. 22-31
Author(s):  
S Wansi ◽  
Syahran Wael
Keyword(s):  
Treatment Duration ◽  
Laboratory Experiments ◽  
Health Benefits ◽  
Biology Education ◽  
The Body ◽  
Test Results ◽  
Tukey Test ◽  
Study Test ◽  
Chlorine Bleach ◽  
Water Substance

Background: Tea is the most widely consumed beverages by all levels of society because in addition to economical, tea is also thought to provide health benefits. Compounds that contribute to the health of the body such as tannins, catechins, flavanols and cafein. Along with its development era community prefers tea bag as it is easy and practical use. Without realizing it, the longer the brewed tea bag in the water substance called chlorine bleach paper contained in tea bags rather the bag of tea bags will also be dissolved.   Method: This research includes the study of laboratory experiments. Object in this study is 4 (four) brand of tea bag and then examined in a Laboratory Ambon Pattimura University Biology Education using thiosulfate titration methode. Result: Anova and Tukey test results indicate that there are differences in the levels of chlorine-based treatment duration and type of tea steeping. The study test showed was obtained at the highest levels of chlorine treatment A1P4 (0,413 ppm) and A4P1 treatment resulted in the lowest levels of chlorine (0,058 ppm). Conclusion: There are differences in the levels of chlorine in various brands of tea bag is Sariwangi tea, sosro tea, poci tea and tong tji tea for time 2 minutes, 4 minutes, 6 minutes and 8 minutes.

Mapping of induced polarization using natural fields

Geophysics ◽  
2001 ◽  
Vol 66 (1) ◽  
pp. 137-147 ◽  
Author(s):  
Erika Gasperikova ◽  
H. Frank Morrison
Keyword(s):  
Electric Field ◽  
Surrounding Medium ◽  
Low Frequency ◽  
Induced Polarization ◽  
The Body ◽  
Electromagnetic Response ◽  
Frequency Dependent ◽  
Finite Body ◽  
Electric Field Profile ◽  
Measured Response

The observed electromagnetic response of a finite body is caused by induction and polarization currents in the body and by the distortion of the induction currents in the surrounding medium. At a sufficiently low frequency, there is negligible induction and the measured response is that of the body distorting the background currents just as it would distort a direct current (dc). Because this dc response is not inherently frequency dependent, any observed change in response of the body for frequencies low enough to be in this dc limit must result from frequency‐dependent conductivity. Profiles of low‐frequency natural electric (telluric) fields have spatial anomalies over finite bodies of fixed conductivity that are independent of frequency and have no associated phase anomaly. If the body is polarizable, the electric field profile over the body becomes frequency dependent and phase shifted with respect to a reference field. The technique was tested on data acquired in a standard continuous profiling magnetotelluric (MT) survey over a strong induced polarization (IP) anomaly previously mapped with a conventional pole‐dipole IP survey. The extracted IP response appears in both the apparent resistivity and the normalized electric field profiles.

Eco-Physiological Studies of an Intertidal Crustacean, Pollicipes Polymerus (Cirripedia, Lepadomorpha)

1972 ◽  
Vol 57 (1) ◽  
pp. 83-102
Author(s):  
H. J. FYHN ◽  
J. A. PETERSEN ◽  
K. JOHANSEN
Keyword(s):  
Water Loss ◽  
Volume Regulation ◽  
Free Amino ◽  
Heat Load ◽  
Laboratory Experiments ◽  
Sea Water ◽  
Physiological Responses ◽  
The Body ◽  
Air Exposure ◽  
Pollicipes Polymerus

1. Physiological responses to environmental stresses of the intertidal cirriped Pollicipes polymerus have been studied by combined field and laboratory experiments. 2. The body temperature of air-exposed animals is always lower than expected from the heat load. Evaporation from the peduncle is responsible for the heat loss. 3. The rate of water loss by evaporation from the peduncle cuticle is 1.5 µl/cm2 h mmHg both at 21 and 27 °C. The transpiration is proportional to the saturation deficit of the air. The water loss from the capitulum is negligible in comparison to that from the peduncle. 4. The haemolymph osmolality of animals in the field increases during exposure to sunshine and decreases during exposure to rain. The increase in haemolymph osmolality during desiccation is equal to that calculated from the decrease in body water. The water loss during air exposure is adequately replaced during submersion, probably by osmosis. 5. Pollicipes is an osmoconformer but is 5-20 m-osmoles hyperosmotic. It tolerates sea-water dilutions down to about 50%. The hyperosmolality seems to be balanced by a high internal hydrostatic pressure. 6. An excretory activity is observed. The excretion is isosmotic to the haemolymph and is possibly an ultrafiltrate of the latter. 7. The muscle cells show volume regulation, but free amino acids seem to be unimportant in regulation of intracellular osmolality. The concentration of ninhydrinpositive substances in the muscle tissue is about 200 mM for animals in full strength sea water.

scholarly journals A biogenic secondary organic aerosol source of cirrus ice nucleating particles

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Martin J. Wolf ◽  
Yue Zhang ◽  
Maria A. Zawadowicz ◽  
Megan Goodell ◽  
Karl Froyd ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Secondary Organic Aerosol ◽  
Global Climate ◽  
Compositional Analysis ◽  
Field Measurements ◽  
Organic Aerosol ◽  
Cloud Formation ◽  
Ambient Atmosphere ◽  
Atmospheric Conditions ◽  
Mass Fractions

Abstract Atmospheric ice nucleating particles (INPs) influence global climate by altering cloud formation, lifetime, and precipitation efficiency. The role of secondary organic aerosol (SOA) material as a source of INPs in the ambient atmosphere has not been well defined. Here, we demonstrate the potential for biogenic SOA to activate as depositional INPs in the upper troposphere by combining field measurements with laboratory experiments. Ambient INPs were measured in a remote mountaintop location at –46 °C and an ice supersaturation of 30% with concentrations ranging from 0.1 to 70 L–1. Concentrations of depositional INPs were positively correlated with the mass fractions and loadings of isoprene-derived secondary organic aerosols. Compositional analysis of ice residuals showed that ambient particles with isoprene-derived SOA material can act as depositional ice nuclei. Laboratory experiments further demonstrated the ability of isoprene-derived SOA to nucleate ice under a range of atmospheric conditions. We further show that ambient concentrations of isoprene-derived SOA can be competitive with other INP sources. This demonstrates that isoprene and potentially other biogenically-derived SOA materials could influence cirrus formation and properties.

scholarly journals Single Transparent Piezoelectric Detector for Optoacoustic Sensing—Design and Signal Processing

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2195 ◽  
Author(s):  
Elias Blumenröther ◽  
Oliver Melchert ◽  
Jonas Kanngießer ◽  
Merve Wollweber ◽  
Bernhard Roth
Keyword(s):  
Response Function ◽  
Indium Tin Oxide ◽  
Near Field ◽  
Depth Profiling ◽  
Field Measurements ◽  
Pressure Profile ◽  
Test Sample ◽  
Instrument Response Function ◽  
Electrically Conducting ◽  
Instrument Response

In this article, we present a simple and intuitive approach to create a handheld optoacoustic setup for near field measurements. A single piezoelectric transducer glued in between two sheets of polymethyl methacrylate (PMMA) facilitates nearfield depth profiling of layered media. The detector electrodes are made of indium tin oxide (ITO) which is both electrically conducting as well as optically transparent, enabling an on-axis illumination through the detector. By mapping the active detector area, we show that it matches the design form precisely. We also present a straightforward approach to determine the instrument response function, which allows to obtain the original pressure profile arriving at the detector. To demonstrate the validity of this approach, the measurement on a simple test sample is deconvolved with the instrument response function and compared to simulation results. Except for the sputter instrumentation, all required materials and instruments as well as the tools needed to create such a setup are available to standard scientific laboratories.

THREE‐DIMENSIONAL INDUCED POLARIZATION AND ELECTROMAGNETIC MODELING

Geophysics ◽  
1975 ◽  
Vol 40 (2) ◽  
pp. 309-324 ◽  
Author(s):  
Gerald W. Hohmann
Keyword(s):  
Integral Equation ◽  
Green's Functions ◽  
Green’S Functions ◽  
Three Dimensional ◽  
Induced Polarization ◽  
The Body ◽  
Scale Model ◽  
Two Dimensional ◽  
Electromagnetic Modeling ◽  
The Earth

The induced polarization (IP) and electromagnetic (EM) responses of a three‐dimensional body in the earth can be calculated using an integral equation solution. The problem is formulated by replacing the body by a volume of polarization or scattering current. The integral equation is reduced to a matrix equation, which is solved numerically for the electric field in the body. Then the electric and magnetic fields outside the inhomogeneity can be found by integrating the appropriate dyadic Green’s functions over the scattering current. Because half‐space Green’s functions are used, it is only necessary to solve for scattering currents in the body—not throughout the earth. Numerical results for a number of practical cases show, for example, that for moderate conductivity contrasts the dipole‐dipole IP response of a body five units in strike length approximates that of a two‐dimensional body. Moving an IP line off the center of a body produces an effect similar to that of increasing the depth. IP response varies significantly with conductivity contrast; the peak response occurs at higher contrasts for two‐dimensional bodies than for bodies of limited length. Very conductive bodies can produce negative IP response due to EM induction. An electrically polarizable body produces a small magnetic field, so that it is possible to measure IP with a sensitive magnetometer. Calculations show that horizontal loop EM response is enhanced when the background resistivity in the earth is reduced, thus confirming scale model results.

A Scaling Law for the Urban Heat Island Phenomenon: Deductions From Field Measurements and Comparisons With Existing Results From Laboratory Experiments

2014 ◽  
Author(s):  
Marina K.-A. Neophytou ◽  
Harindra J. S. Fernando ◽  
Ekaterina Batchvarova ◽  
Mats Sandberg ◽  
Jos Lelieveld ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Laboratory Experiments ◽  
Scaling Law ◽  
Field Measurements ◽  
Capital City ◽  
Mitigation Measures ◽  
Heat Island ◽  
Multi Scale ◽  
Urban Heat ◽  
The Impact

We report results from a multi-scale field experiment conducted in Cyprus in July 2010 in order to investigate the Urban Heat Island (UHI) in Nicosia capital city and its interaction with multi-scale meteorological phenomena taking place in the broader region. Specifically, the results are analysed and interpreted in terms of a non-dimensional/scaling parameter dictating the urban heat island circulation reported from laboratory experiments (Fernando et al, 2010). We find that the field measurements obey the same scaling law during the day, in the absence of any other flow phenomena apart from the urban heating. During the night we find that the deduced non-dimensional value reduces to half (compared to that during the day); this is due to the presence of katabatic winds from Troodos mountains into the urban center of Nicosia and their cooling effect superimposed on diurnal urban heating. Based on this deduction, the impact of various proposed heat island mitigation measures in urban planning can be evaluated.

Leaves as “crackers”, biofilm as “peanut butter”: Exploratory use of stable isotopes as evidence for microbial pathways in detrital food webs

2011 ◽  
Vol 40 (4) ◽  
Author(s):  
Robert France
Keyword(s):  
Energy Source ◽  
Stable Isotopes ◽  
Food Webs ◽  
Laboratory Experiments ◽  
Peanut Butter ◽  
Field Measurements ◽  
Nitrogen Isotope ◽  
Allochthonous Organic Matter ◽  
Stable Nitrogen Isotope ◽  
Microbial Biofilms

AbstractLaboratory experiments have shown benthic macroinvertebrates to be capable of consuming heterotrophic organisms which develop on decomposing terrestrial leaves. Questions remain, however, as to whether these microbial biofilms represent a significant energy source to macroinvertebrates within the natural environment compared to that supplied by leaf substrates themselves. A compilation of literature data on field measurements of stable nitrogen isotope ratios for herbivorous macroinvertebrates suggests that assimilation of microbial biofilms may be the principle means by which allochthonous organic matter enters freshwater detrital food webs.

A GEOPHYSICAL CASE HISTORY OF THE LAKESHORE ORE BODY

Geophysics ◽  
1971 ◽  
Vol 36 (6) ◽  
pp. 1232-1249 ◽  
Author(s):  
Philip G. Hallof ◽  
Emil Winniski
Keyword(s):  
Direct Detection ◽  
El Paso ◽  
Geophysical Methods ◽  
Field Measurements ◽  
Induced Polarization ◽  
Copper Ore ◽  
Ore Body ◽  
Ore Mineralization ◽  
History Of ◽  
Geophysical Technique

The Lakeshore ore body is in Pinal County, Arizona about 30 miles south of Casa Grande. In February, 1969 when the latest figures were published, the ore reserves were reported at 241 million tons of disseminated sulfide ore (0.7 percent copper) and 24 million tons of concentrated metallic ore (1.69 percent copper). Sulfide copper ore was first intersected in July, 1967 in Hole P‐3. The magnetite‐pyrite‐chalco‐pyrite mineralization occurred in a banded tactite at a depth of 1147 ft. Hole P‐3 was the fourth of several holes that were drilled to determine the source of an induced polarization anomaly that had been outlined, at depth, to the west of the old Lakeshore pit. The successful conclusion of this exploration program by El Paso Natural Gas Company is an excellent example of an integrated exploration approach. The application of regional geological planning, geophysical methods, and detailed geological reasoning resulted in the discovery of a major copper ore body. Due to the depth of the ore zone and the disseminated character of most of the ore, the only geophysical technique that was useful in the direct detection of the ore mineralization was the induced polarization method. Field measurements were made sporadically between August, 1966 and July, 1968. Variable‐frequency induced‐polarization measurements, made using the dipole‐dipole electrode configuration and electrode intervals from 300 ft to 1000 ft, successfully indicated the presence of the metallic mineralization at depth and gave some indication of its extent. Comparisons of the induced polarization data and the appropriate geological sections give information concerning the usefulness of the method.

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