THE APPLICATION OF A THREE‐ELEMENT MODEL TO THE S.P. AND RESISTIVITY PHENOMENA EVINCED BY DIRTY SANDS

Geophysics ◽  
1955 ◽  
Vol 20 (4) ◽  
pp. 913-931 ◽  
Author(s):  
J. G. McKelvey ◽  
P. F. Southwick ◽  
K. S. Spiegler ◽  
M. R. J. Wyllie

A simple resistor model consisting of three elements in parallel and representing (a) an element of solution and conducting solid particles in series, (b) an element of the solid particles only, and (c) an element of solution only, explains satisfactorily the experimental relationship between the conductivities of solutions used to saturate synthetic dirty sands and the conductivities of the saturated sands. The synthetic dirty sands consist of beds of ion‐exchange particles. The same model is applied to give a theoretical explanation of the potential differences between two different solutions when these meet in the interstices of a synthetic dirty sand; excellent agreement is observed between theory and experiment. It is found that both potentials and resistivities depend on the same geometrical parameters. Hence they can be related to each other. The relationship is derived between the self‐potential deflection and the resistivities of rock and invaded zone. It is compared to various formulae proposed by other investigators for interpreting logs in dirty sands. Conductivities and potential differences across plugs of “synthetic dirty sands” containing oil have been measured. At high oil saturations the potential differences are almost as high as those across a solid membrane containing the same ion‐exchange resin.

2015 ◽  
Vol 27 (3) ◽  
pp. 390-396 ◽  
Author(s):  
Lu Wang ◽  
Xiaolan Liu ◽  
Xiqun Zheng ◽  
Yinghua Tian

Purpose – Building the relationship between retting termination and pectin content remained in the fiber is crucial for ensuring the identity quality of retted flax. In order to measure the pectin content, pectin must be removed thoroughly from the fiber. The purpose of this paper is to find the most suitable method to extract pectin from flax phloem fiber. Design/methodology/approach – Methods of extracting pectin from fruits were employed to ensure the complete removal of pectin from flax for the first time, including extraction with ethylene diamine tetraacetic acid, hydrochloric acid and ion exchange resin. Traditional ammonium oxalate-KOH method was adopted as control. Each procedure was optimized according to the yield of pectin. A characteristic chromogenic technique for determining the exact pectin amount was used, which ensured the precise measurement of pectin extracted. Findings – Results showed that comparing with the traditional ammonium oxalate-KOH method, methods of hydrochloric acid and ion exchange resin extract >95 percent (w/w) pectin and the extract conditions are much milder. Originality/value – Bulk of literatures have covered the problem of how to define the quality of retted flax. But the flax industry in China still uses sensory method to check the retting termination. Connect the fiber quality with pectin content is a brand new idea. Also, the exaction method employed from fruit pectin extract is applied in flax pectin for the first time. These methods are essential for building the relationship between the pectin content and retting termination and also significant for discovering the suitable enzyme for enzyme retting.


2016 ◽  
Vol 52 ◽  
pp. 171-176
Author(s):  
M. Palkina ◽  
O. Metlitska

The aim of the research – adaptation, optimization and using of existing DNA extraction methods from bees’ biological material with the reagent «Chelex-100" under complex economic conditions of native laboratories, which will optimize labour costs and improve the economic performance of DNA extraction protocol. Materials and methods. In order to conduct the research the samples of honey bees’ biological material: queen pupae exuviae, larvae of drone brood, some adult bees’ bodies (head and thorax) were selected. Bowl and drone brood were obtained from the experimental bee hives of Institute of Apiculture nd. a. P. I. Prokopovich of NAAS. DNA extraction from biosamples of Apis mellifera ssp. was carried out using «Chelex-100®» ion exchange resin in different concentrations and combinations. Before setting tests for determination of quantitative and quality indexes, dilution of DNA samples of the probed object was conducted in ratio 1:40. The degree of contamination with protein and polysaccharide fractions (OD 260/230), quantitative content of DNA (OD 260/280) in the extracted tests were conducted using spectrophotometer of «Biospec – nano» at the terms of sample volume in 2 µl and length of optical way in 0,7 mm [7]. Verification of DNA samples from biological material of bees, isolated by «Chelex-100®», was conducted after cold keeping during 24 hours at 20°C using PСR with primaries to the fragment of gene of quantitative trait locus (QTL) Sting-2 of next structure [8]:  3' – CTC GAC GAG ACG ACC AAC TTG – 5’; 3' – AAC CAG AGT ATC GCG AGT GTT AC – 5’ Program of amplification: 94 °C – 5 minutes – 1 cycle; 94 °C – 1 minute, 57°C – 1 minute, 72 °C – 2 minutes – 30 cycles; elongation after 72°C during 2 minutes – 1 cycle. The division of obtained amplicons was conducted by gel electrophoresis at a low current – 7 µÀ, in 1,5 % agarose gel (Sigma ®) in TAE buffer [7]. The results. At the time of optimization of DNA isolation methods, according to existing methods of foreign experts, it was found optimal volume of ion exchange resin solution was in the proposed concentration: instead of 60 µl of solution used 120 µl of «Chelex-100®», time of incubation was also amended from 30 minutes to 180 minutes [9]. The use of the author's combination of method «Chelex-100®» with lysis enzymes, proteinase K and detergents (1M dithiothreitol), as time of incubation was also amended, which was reduced to 180 minutes instead of the proposed 12 hours [10]. Changes in quality characteristics of obtained DNA in samples after reduction in incubation time were not found. Conclusions. The most economical method of DNA isolation from bees’ biological material is 20% solution of «Chelex-100» ion exchange resin with the duration of the incubation period of 180 minutes. It should also be noted that the best results can be obtained from exuviae, selected immediately after the queen’s exit from bowl, that reduces the likelihood of DNA molecules destruction under the influence of nucleases activation, but not later than 12 hours from release using the technology of isolated obtain of queens.


1977 ◽  
Vol 49 (6) ◽  
pp. 764-766 ◽  
Author(s):  
Toshihiko. Hanai ◽  
Harold F. Walton

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