THE USE OF CUMULATIVE RESISTANCE IN EARTH-RESISTIVITY SURVEYS

1945 ◽  
Vol 23a (4) ◽  
pp. 57-72 ◽  
Author(s):  
R. Ruedy
Keyword(s):  
Apparent Resistivity ◽  
Middle Layer ◽  
The Other ◽  
Electrode Spacing ◽  
Line Graphs ◽  
Earth Resistivity ◽  
The Earth ◽  
Straight Line ◽  
The Individual

When the soil is assumed to consist of two layers—the upper of resistivity ρ1 and the lower of resistivity ρ2—and cumulative resistances are calculated by adding or integrating the earth-resistivity functions for intervals that are a fraction of the thickness of the upper layer, a practically linear relation is obtained between the cumulative resistance and the electrode spacing until the distance between the electrodes is equal to the thickness of the upper material. Should one of the materials be at least twice as conducting as the other, the extent of the deviation from the linear law enables the determination of the depth of the upper stratum and of the ratio between the resistivities of the two layers. When three layers are present and the middle layer is at least twice as thick as the top stratum, the thicknesses may be deduced from the two departures of the cumulative resistances from the linear law. Since these conclusions are based on the theory of the individual apparent resistivity of stratified ground at various electrode spacings, they have the same range of application as the earth-resistivity curves, but the occurrence of straight line graphs facilitates the plotting and the interpretation of results based on a necessarily limited number of measurements.

Determination of Sulfaquinoxaline, Sulfathiazole, Sulfamerazine, and Sulfamethazine in Feed Concentrates or Premixes

1973 ◽  
Vol 56 (6) ◽  
pp. 1475-1479 ◽  
Author(s):  
Ugo R Cieri
Keyword(s):  
Silica Gel ◽  
The Other ◽  
Uv Absorbance ◽  
The Individual

Abstract Sulfaquinoxaline is determined by its UV absorbance at about 358 nm, where the other 3 sulfonamides do not absorb. Sulfathiazole, sulfamerazine, and sulfamethazine are determined by a quantitative TLC procedure, based on the separation of the compounds on silica gel plates; the spots are extracted and the centrifuged extracts are analyzed spectro-photometrically. A method of calculating the total sulfonamide content, independent of the individual components, is also introduced.

scholarly journals Limiting factors in the field of business activities in rural tourism

2008 ◽  
Vol 53 (No. 9) ◽  
pp. 421-431 ◽  
Author(s):  
K. Ryglová
Keyword(s):  
Czech Republic ◽  
Rural Areas ◽  
Rural Population ◽  
Rural Tourism ◽  
The Other ◽  
Limiting Factors ◽  
The Czech Republic ◽  
Tourist Infrastructure ◽  
The Individual

This paper deals with problems of rural tourism development. The works is focused on researching the situation in the area of rural tourism in the Czech Republic, on understanding the attitudes of entrepreneurial sphere and rural population to this entrepreneurship and mainly on the determination of limiting factors that prevent this form of tourism from a more distinctive development. Rural tourism in the Czech Republic is still in the initiating stage of its development and it is not as developed as in some countries in West Europe. This goal has been reached with the help of primary questionnaire inquiry among business and agricultural subjects in rural areas in the individual regions and the detail results of this questionnaire inquiry are enclosed to the following paper. These identified factors were mainly insufficient financial means and at the same time insufficient state assistance connected with this. Insufficient awareness of this support as well as its inaccessibility for small business appears to be a difficulty, too. From the other obstacles, we can mention the current legislation system, bureaucracy, the state of communication and tourist infrastructure, fears of neighbours’ intolerance and losing privacy and also unfamiliarity and little experience.

DEEP ELECTRICAL PROSPECTING—A DISCUSSION

Geophysics ◽  
1948 ◽  
Vol 13 (1) ◽  
pp. 92-97
Author(s):  
Sulhi Yüngül
Keyword(s):  
Apparent Resistivity ◽  
The Other ◽  
New Method ◽  
Depth Of Penetration ◽  
Method Of Calculation ◽  
Comprehensive Knowledge ◽  
Electrical Sounding ◽  
The Subject ◽  
Electrical Prospecting

In two papers published in Geophysics, one in the October, 1944, issue and the other in October, 1946, a system and method of calculation, called “Resistolog” method, was presented. The object of the Resistolog method is to eliminate the effects of superficial inhomogeneities which are the most troublesome obstacles in interpreting electrical sounding results in exploring deep, horizontal discontinuities. The following is a discussion of the papers mentioned above, mainly of the subject of (1) the apparent‐resistivity formula derived for use with the Resistolog configuration, (2) determination of inflectional points on apparent resistivity curves, (3) depth of penetration, and (4) distortion caused by the “far electrode.” A new method to determine inflectional points is also given. This paper includes a comprehensive knowledge about the forementioned papers and the reader may not have to refer to them.

scholarly journals Two-dimensional Electrical Resistivity Tomography of Bitumen Occurrence in Agbabu, Southwest Nigeria

2019 ◽  
pp. 1-9
Author(s):  
O. F. Ogunlana ◽  
O. M. Alile ◽  
O. J. Airen
Keyword(s):  
Electrical Resistivity ◽  
Apparent Resistivity ◽  
Electrical Resistivity Tomography ◽  
Electrode Spacing ◽  
Southwestern Nigeria ◽  
Resistivity Tomography ◽  
2D Inversion ◽  
Earth Resistivity ◽  
Southwest Nigeria ◽  
Resistivity Meter

The Electrical Resistivity Tomography (ERT) data was acquired within the area suspected to have high potential for bitumen occurrence using the Wenner-Schlumberger configuration in Agbabu, southwestern Nigeria. PASI 16GL-N Earth resistivity meter instrument was used to acquire data along five (5) traverses with 5m electrode spacing and traverses length of 150m. The apparent resistivity values obtained was processed using RES2DINV software which helped to automatically obtain the 2D inversion model of the subsurface. This study has shown the occurrence of bitumen between the depth of 13.4m and 9.93m for Traverses 1, 2, 3 and Traverses 4, 5 respectively in a 2-Dimensional electrical resistivity images for boreholes with a depth of about 18m. The results indicate that the bitumen is characterized by good lateral continuity and is sufficiently thick for commercial exploitation.

scholarly journals ALGORITHMS FOR CALCULATING GEODETIC HEIGHTS AND LATITUDES BY RECTANGULAR COORDINATES IN THE MERIDIAN ELLIPSE PLANE

2021 ◽  
Vol 26 (5) ◽  
pp. 5-16
Author(s):  
Alexander V. Elagin ◽  
◽  
Natalia N. Kobeleva ◽  
Keyword(s):  
Reference Values ◽  
Intersection Point ◽  
The Other ◽  
Geodetic Coordinates ◽  
The Earth ◽  
Straight Line ◽  
Rectangular Coordinates ◽  
Spatial Coordinates ◽  
Point Of Intersection ◽  
The Given

Owing to the widespread use of GNSS technologies in geodetic practice, the problem arises of transition from rectangular spatial coordinates of points to spatial geodetic coordinates, which are necessary for the transition to flat rectangular coordinates in the Gauss-Kruger projection. The authors proposed five algorithms for converting rectangular coordinates of points in the plane of the meridian ellipse into geodetic heights and latitudes. The first two algorithms are geometrically related to the intersection point of the ellipse with the normal passing through the point at which the rectangular spatial coordinates were obtained. The formulas of the other three algorithms are based on the geometric relationships of the point of intersection of the meridian ellipse with the straight line connecting the point with the center of curvature of the meridian. As a result of the experiments, deviations of the calculated latitudes and heights from the reference values of the given grid of geodetic coordinates were obtained. The formulas were tested not only for points under and on the earth's surface, but also outside the earth at different heights up to an altitude of 20,000 km.

scholarly journals Identical appended series of points as invariants in the collocal general-colinear fields

2003 ◽  
Vol 2 (5) ◽  
pp. 387-394
Author(s):  
Sonja Krasic
Keyword(s):  
The Other ◽  
Straight Line ◽  
Similar Series ◽  
Vanishing Line ◽  
Identical Series ◽  
Straight Lines ◽  
General Method

In order to bring the collocal collinear fields from the general into the perspective position, it is required to determine the identical appended series of points. Because of the properties depending on the projectivity that is given by the four appended points (straight lines) the appended identical series of the points and types are ranked among the invariants of general-collinear and perspectively-collinear fields. The procedure of determination of appended identical series of points is comprised of the following: in the set of ?1 of perspectively similar series in one field (whose center of perspective is a point on the vanishing line), find those that are identical to all the series in the set ?1 of perspective identical series of points in the other field (whose center of perspective is the point on the infinitely distant straight line). In the procedure, one begins from the appended similar methods obtained by the general method. The procedure is simplified by the introduction of the specially given similar series of points.

Interpretation of velocity spectra

Geophysics ◽  
1980 ◽  
Vol 45 (12) ◽  
pp. 1741-1752 ◽  
Author(s):  
Allen B. Cunningham ◽  
Harland H. Heffring
Keyword(s):  
Linear Time ◽  
Data Gathering ◽  
Multiple Reflections ◽  
Machine Method ◽  
Straight Line ◽  
Composite Section ◽  
Seismic Sections ◽  
Velocity Spectra ◽  
The Individual

One major effort in processing seismic data is that of correcting for the geometric effects or normal moveout introduced by multichannel data gathering procedures. Usually, this involves detecting coherent reflected signals, determining a time (t) versus moveout (Δt) relationship for these signals, time correcting the individual receiver traces, and combining selected traces into a stacked or composite section. Most of these operations are automated. Several velocity analysis techniques are available for detecting reflections automatically, and individual trace correcting and combining procedures are trivial. However, determination of a moveout function which will discriminate among valid reflections, multiple reflections, and noise is still largely a human operation. We describe a machine method devised to determine automatically these moveout, or t‐Δt, functions, as they are commonly called. The method makes extensive use of the observed phenomenon that the t‐Δt function is well approximated by a segmented straight‐line curve when plotted on a logarithmic moveout (Δt) versus linear time (t) graph. Criteria for determining these straight‐line functions, which include a constraint on the line segment slopes, are discussed; several examples resulting from their use are shown. In the examples, seismic sections corrected by our machine‐derived moveout functions are compared with those corrected by more conventionally determined functions.

Discussion of paper by A. R. Clark entitled “The Determination of the Long Dimension of Conducting Ore Bodies”

Geophysics ◽  
1956 ◽  
Vol 21 (2) ◽  
pp. 477-478
Author(s):  
Bruno Kunz
Keyword(s):  
Apparent Resistivity ◽  
Semimajor Axis ◽  
Electrode Spacing ◽  
Logarithmic Scale ◽  
Master Curves ◽  
Resistivity Ratio ◽  
Ore Bodies ◽  
The Absolute ◽  
Short Time

When J. N. Hummel published his first apparent resistivity curves some 30 years ago, he used coordinates with a linear scale. A short time later it was found that such master curves are universally usable only when plotted on logarithmic scales. The reason for this is that the shape of the curves does not depend upon the absolute electrode spacing and the absolute resistivity values but only on the relative values. This, naturally, also holds true for the examples shown by A. R. Clark. The curves as shown by him reveal a resistivity ratio of [Formula: see text]. In the same way, the “Distance as a fraction of the Semimajor Axis” is a quotient. Both coordinates should therefore be presented in a logarithmic scale. When so plotted, the characteristic properties of the curves are much more conspciuous and are very different from those when linear scales are used. The remarks made by the author relative to the shape of the curves may have to be revised.

scholarly journals A study of transient variations in the Earth's electromagnetic field at equatorial electrojet latitudes in western Africa (Mali and the Ivory Coast)

1998 ◽  
Vol 16 (6) ◽  
pp. 677-697 ◽  
Author(s):  
J. Vassal ◽  
M. Menvielle ◽  
Y. Cohen ◽  
M. Dukhan ◽  
V. Doumouya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Diurnal Variation ◽  
Apparent Resistivity ◽  
Equatorial Electrojet ◽  
The Other ◽  
Source Effect ◽  
The Earth ◽  
Magnetic Signature ◽  
Transient Variations ◽  
The Magnetic Field

Abstract. In the framework of the French-Ivorian participation to the IEEY, a network of 10 electromagnetic stations were installed at African longitudes. The aim of this experiment was twofold: firstly, to study the magnetic signature of the equatorial electrojet on the one hand, and secondly, to characterize the induced electric field variations on the other hand. The first results of the magnetic field investigations were presented by Doumouya and coworkers. Those of the electric field experiment will be discussed in this study. The electromagnetic experiment will be described. The analysis of the electromagnetic transient variations was conducted in accordance with the classical distinction between quiet and disturbed magnetic situations. A morphological analysis of the recordings is given, taking into consideration successively quiet and disturbed magnetic situations, with the results interpreted in terms of the characterization of external and internal sources. Particular attention was paid to the effects of the source characteristics on the induced field of internal origin, and to the bias they may consequently cause to the results of electromagnetic probing of the Earth; the source effect in electromagnetic induction studies. During quiet magnetic situations, our results demonstrated the existence of two different sources. One of these, the SRE source, was responsible for most of the magnetic diurnal variation and corresponded to the well-known magnetic signature of the equatorial electrojet. The other source (the SR*E source) was responsible for most of the electric diurnal variation, and was also likely to be an ionospheric source. Electric and magnetic diurnal variations are therefore related to different ionospheric sources, and interpreting the electric diurnal variation as induced by the magnetic field diurnal variation is not relevant. Furthermore, the magnetotelluric probing of the upper mantle at dip equator latitudes with the electromagnetic diurnal variation is consequently impossible to perform. In the case of irregular variations, the source effect related to the equatorial electrojet is also discussed. A Gaussian model of equatorial electrojet was considered, and apparent resistivities were computed for two models of stratified Earth corresponding to the average resistive structure of the two tectonic provinces crossed by the profile: a sedimentary basin and a cratonic shield. The apparent resistivity curves were found to depend significantly on both the model used and the distance to the center of the electrojet. These numerical results confirm the existence of a daytime source effect related to the equatorial electrojet. Furthermore, we show that the results account for the observed differences between daytime and night-time apparent resistivity curves. In particular, it was shown that electromagnetic probing of the Earth using the classical Cagniard-Tikhonov magnetotelluric method is impossible with daytime recordings made at dip latitude stations.Key words. Electromagnetics (Transient and time do- main) Geomagnetism and paleomagnetism (geomagne- tic induction) Ionosphere (equatorial ionosphere)

scholarly journals Some Analytical Aspects of the Immunochemical Determination of the Selectivity of Proteinuria

1974 ◽  
Vol 11 (1-6) ◽  
pp. 59-66 ◽  
Author(s):  
R. Beetham ◽  
R. J. Mills ◽  
D. N. Raine ◽  
R. H. R. White
Keyword(s):  
Nephrotic Syndrome ◽  
The Other ◽  
Sample Storage ◽  
Double Immunodiffusion ◽  
Glomerular Lesion ◽  
Acid Glycoprotein ◽  
Immunochemical Determination ◽  
The Individual ◽  
Limited Period

The selectivity of proteinuria has been determined from the relative clearances of α1-acid glycoprotein, albumin, transferrin and IgG in 190 children and adolescents. The precision of the determination of selectivity (C.V. = 3%) is greater than that of the individual protein clearances determined by a double immunodiffusion method (C.V. = 13–22%). Neither sample storage for a limited period nor concentrating the urine affects the selectivity value significantly; serial determinations in one patient for 24 h showed no diurnal variation. The effectiveness of selectivity in predicting the steroid response in the nephrotic syndrome was found to be slightly superior when determined from all four proteins than from transferrin and IgG alone. Inclusion of α2-macroglobulin relative clearance in the selectivity determination often significantly alters the value determined from the other four proteins alone. The reasons for this are discussed. Demonstration of α2M in urine which has not been concentrated, strongly suggests the presence of a structural glomerular lesion.

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