Hydrogeological applications of the empirical approach to water resistivity - salinity relationships

1971 ◽  
Vol 2 (4) ◽  
pp. 35
Author(s):  
B.M. Haines ◽  
D.W. Emerson ◽  
M.J. Smith
Keyword(s):  
Direct Measurement ◽  
Empirical Relationship ◽  
Approximate Solutions ◽  
Difficult Problem ◽  
Well Logs ◽  
Quantitative Interpretation ◽  
Satisfactory Solution ◽  
Subsequent Determination ◽  
Water Resistivity

Hydrogeological evaluation of subsurface aquifers involves measurement of electrolyte resistivity and subsequent determination of solution salinity. Resistivity of the water may be evaluated by quantitative interpretation of electrical well logs or by direct measurement on recovered samples. Determination of a reliable relationship between electrolyte resistivity and salinity presents a more difficult problem. Approximate solutions have been attempted frequently on theoretical and experimental bases. An empirical relationship derived from previously collected data provides the most satisfactory solution for any particular situation (be it region, valley, basin or aquifer).

A VELOCITY FUNCTION INCLUDING LITHOLOGIC VARIATION

Geophysics ◽  
1953 ◽  
Vol 18 (2) ◽  
pp. 271-288 ◽  
Author(s):  
L. Y. Faust
Keyword(s):  
Travel Time ◽  
Direct Measurement ◽  
General Knowledge ◽  
Velocity Function ◽  
Geologic Time ◽  
True Resistivity ◽  
Resistivity Log ◽  
Vertical Travel ◽  
Water Resistivity

Assuming velocity (V) a function of depth (Z), geologic time (T), and lithology (L) the resistivity log is an approach to the determination of L. Since general knowledge of water resistivity values [Formula: see text] is lacking, the values of true resistivity [Formula: see text] against [Formula: see text] were compared for 670,000 feet of section widely distributed geographically. Variations in [Formula: see text] were presumably averaged out thereby, and the results indicate that statistically [Formula: see text] and [Formula: see text] This formula was applied to an additional 270,000 feet of section more localized geographically to observe its accuracy in predicting vertical travel time. If a correction map for [Formula: see text] variations is applied the results are encouraging but less accurate than good velocity surveys. Examination of an inconclusively small amount of data with more careful measurements of [Formula: see text] suggests that accuracy comparable to direct measurement may be attainable. The cooperation of other investigators and of the electric‐logging specialists is desired.

Sorption of Se (IV) from aqueous solutions with subsequent determination by X-ray fluorescence analysis

2020 ◽  
Vol 86 (10) ◽  
pp. 5-9
Author(s):  
D. G. Filatova ◽  
A. A. Arkhipenko ◽  
M. A. Statkus ◽  
V. V. Es’kina ◽  
V. B. Baranovskaya ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Fluorescence Analysis ◽  
Standard Samples ◽  
Phase Contact Time ◽  
Sorbent Phase ◽  
X Ray ◽  
Fundamental Parameters ◽  
Inductively Coupled ◽  
Subsequent Determination

An approach to sorptive separation of Se (IV) from solutions on a novel S,N-containing sorbent with subsequent determination of the analyte in the sorbent phase by micro-x-ray fluorescence method is presented. The sorbent copolymethylenesulfide-N-alkyl-methylenamine (CMA) was synthesized using «snake in the cage» procedure and proven to be stable in acid solutions. Conditions for quantitative extraction of Se (IV) were determined: sorption in 5 M HCl or 0.05 M HNO3 solutions when heated to 60°C, phase contact time being 1 h. The residual selenium content in the solution was determined by inductively coupled plasma mass spectrometry (ICP-MS) using 82Se isotope. The absence of selenium losses is proved and the mechanism of sorption interaction under specified conditions is proposed. The method of micro-x-ray fluorescence analysis (micro-RFA) with mapping revealed a uniform distribution of selenium on the sorbent surface. The possibility of determining selenium in the sorbent phase by micro-RFA is shown. When comparing the obtained results with the results of calculations by the method of fundamental parameters, it is shown the necessity of using standard samples of sorbates to obtain correct results of RFA determination of selenium in the sorbent phase.

Tribology of rail bogie

2018 ◽  
Vol 77 (4) ◽  
pp. 230-240
Author(s):  
D. P. Markov
Keyword(s):  
Contact Fatigue ◽  
Basic Element ◽  
Difficult Problem ◽  
Railway Track ◽  
Rolling Stock ◽  
Kinematic Parameters ◽  
Approximate Estimation ◽  
Railway Bogie ◽  
Classical Calculation

Railway bogie is the basic element that determines the force, kinematic, power and other parameters of the rolling stock, and its movement in the railway track has not been studied enough. Classical calculation of the kinematic and dynamic parameters of the bogie's motion with the determination of the position of its center of rotation, the instantaneous axes of rotation of wheelsets, the magnitudes and directions of all forces present a difficult problem even in quasi-static theory. The paper shows a simplified method that allows one to explain, within the limits of one article, the main kinematic and force parameters of the bogie movement (installation angles, clearance between the wheel flanges and side surfaces of the rails), wear and contact damage to the wheels and rails. Tribology of the railway bogie is an important part of transport tribology, the foundation of the theory of wheel-rail tribosystem, without which it is impossible to understand the mechanisms of catastrophic wear, derailments, contact fatigue, cohesion of wheels and rails. In the article basic questions are considered, without which it is impossible to analyze the movement of the bogie: physical foundations of wheel movement along the rail, types of relative motion of contacting bodies, tribological characteristics linking the force and kinematic parameters of the bogie. Kinematics and dynamics of a two-wheeled bogie-rail bicycle are analyzed instead of a single wheel and a wheelset, which makes it clearer and easier to explain how and what forces act on the bogie and how they affect on its position in the rail track. To calculate the motion parameters of a four-wheeled bogie, it is represented as two two-wheeled, moving each on its own rail. Connections between them are replaced by moments with respect to the point of contact between the flange of the guide wheel and the rail. This approach made it possible to give an approximate estimation of the main kinematic and force parameters of the motion of an ideal bogie (without axes skewing) in curves, to understand how the corners of the bogie installation and the gaps between the flanges of the wheels and rails vary when moving with different speeds, how wear and contact injuries arise and to give recommendations for their assessment and elimination.

scholarly journals Indirect spectrophotometric determination of gentamicin and vancomycin antibiotics based on their oxidation by potassium permanganate

2006 ◽  
Vol 4 (4) ◽  
pp. 708-722 ◽  
Author(s):  
Akram El-Didamony ◽  
Alaa Amin ◽  
Ahmed Ghoneim ◽  
Ayman Telebany
Keyword(s):  
Acid Medium ◽  
Potassium Permanganate ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Reaction Conditions ◽  
Subsequent Determination ◽  
Optimum Reaction ◽  
Acid Orange Ii ◽  
Sulphuric Acid Medium

AbstractFour simple, accurate, sensitive and economical procedures (A–D) for the estimation of gentamicin sulphate and vancomycin hydrochloride, both in pure form and in pharmaceutical formulations have been developed. The methods are based on the oxidation of the studied drugs by a known excess of potassium permanganate in sulphuric acid medium and subsequent determination of unreacted oxidant by reacting it with amaranth dye (method A), acid orange II (method B), indigocarmine (method C) and methylene blue (method D), in the same acid medium at a suitable λmax=521, 485, 610 and 664 nm, respectively. The reacted oxidant corresponds to the drug content. Regression analysis of Beer-Lambert plots showed good correlations in the concentration ranges 4–8, 3–8, 4–9 and 5–9 µg ml−1 with gentamicin and 4–8, 1.5–4, 1.5–4 and 3.5–5.5 µg ml−1 with vancomycin for methods A, B, C, and D, respectively. The molar absorptivity, sandell sensitivity, detection and quantification limits were calculated. The stoichiometric ratios for the cited drugs were studied. The optimum reaction conditions and other analytical parameters were evaluated. The influence of the substance commonly employed as excipients with these drugs were studied. The proposed methods were applied to the determination of these drugs in pharmaceutical formulations. The results have demonstrated that the methods are equally accurate and reproducible as the official methods.

scholarly journals Alkaline Solubilization Method Applied to Industrialized Bread Samples For Subsequent Determination of Cu, Fe, K, Mg, Na and Zn by Atomic Spectrometry

2020 ◽  
Vol 12 (2) ◽  
pp. 368-377
Author(s):  
Ana Claudia Beduhn Luckow ◽  
Daisa Hakbart Bonemann ◽  
Camila Corrêa Pereira ◽  
Alexander Ossanes de Souza ◽  
Anderson Schwingel Ribeiro ◽  
...  
Keyword(s):  
Atomic Spectrometry ◽  
Subsequent Determination

scholarly journals Offshore Operating Agreements

1973 ◽  
Vol 11 (3) ◽  
pp. 503
Author(s):  
D. A. MacWilliam ◽  
R. C. Muir
Keyword(s):  
Advantages And Disadvantages ◽  
New Concepts ◽  
Subsequent Determination ◽  
Canadian Company ◽  
Offshore Operations

The following article analyzes the offshore joint operating agreement in detail. Inter alia, the possible corporate forms Canadian company could use, and their respective advantages and disadvantages, are discussed. The authors consider the new concepts and different provisions and procedures that are necessary to deal with the special problems of offshore operations. Operatorship, with its corresponding rights and obligations, is discussed with emphasis on whether or not challenge clause should be included in the agreement. Independent operations, and the subsequent determination of penalties, are reviewed. The authors discuss problems involved with dis position of production, and in particular, the overlift-underlift clause. Other topics examined are offshore lease selection, sharing of platform costs, and arbitration clauses.

Sorption of As (III) and Se (IV) from aqueous solutions for subsequent determination by total reflection X-ray fluorescence

2021 ◽  
Vol 87 (8) ◽  
pp. 19-22
Author(s):  
D. G. Filatova ◽  
A. A. Arkhipenko ◽  
M. A. Statkus ◽  
I. V. Mikheev ◽  
V. B. Baranovskaya ◽  
...  
Keyword(s):  
Raw Materials ◽  
Total Reflection ◽  
Phase Contact Time ◽  
Sorbent Phase ◽  
X Ray ◽  
Icp Ms ◽  
Subsequent Determination ◽  
Processed Products ◽  
Branched Structure

An approach to the simultaneous isolation of As (III) and Se (IV) from solutions on a new S,N-containing sorbent followed by determination of the analyte in the sorbent phase using total reflection X-ray fluorescence (TXRF) has been proposed. To match the goal, a sorbent with a branched structure was synthesized on the base of polyacrylamide modified with formaldehyde and hydrogen sulfide. This is a heteroatomic copolymer containing sulfide bridges in the chain and crosslinking by a tertiary amine. Conditions for the quantitative co-extraction of As (III) and Se (IV), i.e., sorption in solutions of 1 M HNO3 with calcium ions present, heating to 60°C and phase contact time of 1 h were determined. The mechanism of sorption interaction of the analytes under specified conditions is discussed. It is shown that a 100-fold excess of iron, zinc and copper does not interfere with the extraction of analytes, thus providing the possibility of As (III) and Se (IV) isolation from different types of raw materials and processed products using the synthesized sorbent. A method for the direct XRF quantification of arsenic and selenium with sr 0.09 and 0.08, respectively, in the sorbent phase has been developed. The correctness of the results was confirmed by the ICP-MS method in analysis of aqueous reference solution after dissolution of the sorbate in HNO3 (1:1).

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