The XIth International symposium “polymers and light”

Information Congresses, Conferences, Symposia, Meetings, and Seminars in the Field of Chemical Sciences Held with the Participation of the Russian Academy of Sciences

The XIth International symposium polymers and light     

Reply to comments on EURACHEM/CITAC guide “Measurement uncertainty arising from sampling”

The Eurachem/CITAC Guide on ‘Measurement uncertainty arising from sampling’ describes a number of methods and approaches that can be used for the estimation of this uncertainty. A recent comment upon this Guide by Wilrich questions the expression of the measurement uncertainty in a form that is relative to the concentration, rather than just as an absolute number (i.e. as relative expanded uncertainty rather than expanded uncertainty), in one of the worked examples. This reply argues that the measurement results from the ‘duplicate’ method cannot reliably distinguish between constant standard deviation and constant relative standard deviation over the range observed in the example and that the most appropriate model must accordingly rely on prior knowledge. Since extensive prior knowledge indicates that the precision of sampling and of chemical analysis both tend to increase as a function of concentration, the body of the Guide recommends expression as a relative standard deviation. It is acknowledged that this assumption should be restated with the results of the worked examples as well as in its current position in the main body of the text, in a future edition of the Guide.     

V International symposium “Kinetics in analytical chemistry”

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V International symposium Kinetics in analytical chemistry     

VI International frumkin symposium “Fundamental Aspects of Electrochemistry”

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VI International frumkin symposium Fundamental Aspects of Electrochemistry     

Comments to EURACHEM/CITAC guide “Measurement uncertainty arising from sampling”

The EURACHEM/CITAC Guide “Measurement uncertainty arising from sampling” deals with the design and analysis of experiments for the evaluation of the sampling and analytical standard deviation when a defined sampling and analytical method is used for the determination of the concentration, expressed as mass fraction (mg/kg), of an analyte in a specified material. The Guide recommends reporting the relative expanded uncertainty and using it directly, i.e. it implicitly assumes that the standard deviation is proportional to the mass fraction even in case the experimental data do not support this assumption. Example A1 (and some of the other examples of the Guide) demonstrates that this can result in extreme levels of underestimation or overestimation of the uncertainty of measurement results. Hence, such recommendations should be avoided!     

XXVI International Chugaev Conference on Coordination Chemistry and VII International Symposium “Design and Synthesis of Supramolecular Architectures”

Russian Chemical Bulletin -     

A Review of: “Membrane Applications and Research in Food Processing”

Abstract

C. M. Mohr, S. A. Leeper, D. E. Engelgau, B. L. Charboneau, Noyes Publications, Park Ridge, NJ, November, 1989, cloth, 305 pages, $45.00.     

Measurement and preliminary behavioral model of radioactive “geoaerosols”

Greater than anticipated activity from the á - and â -emittingradionuclides ²³⁰Th+²²⁶Ra, ²¹⁰Po, and ²¹⁰Pb was observed in solution during modification of an air sampler1 to improve the sensitivity of measuring airborne radioactivity. Typicalactivities ranged from several mBq to ¹⁵Bq. We use the term geoaerosols2to describe the particles' unique transport and propose a distinct quantumphenomenon mechanism to explain the radiation accumulation. If confirmed bysubsequent experiments, the technique has potential for many practical applicationssuch as locating faults or fractures, earthquake prediction, mineral and energyresource exploration, verification of underground nuclear testing, and refiningrisk estimates from environmental exposure to particles.     

“One-pot” cascade approach to 5,6-dihydroindolizines and indolizines from pyrrole-2-carbaldehydes and nitroethylenes

Simple and practical reactions of pyrrole-2-carbaldehydes with nitroethylenes provide either the 5,6-dihydroindolizines or the indolizines in one pot, depending on the reaction temperature. Additionally, a plausible mechanism for the entire sequence is proposed.     

Correction to: EQRAIN: uranium and plutonium interlaboratory exercises from 1997 to 2016—comparison to ITVs-2010

Journal of Radioanalytical and Nuclear Chemistry - In the original publication of the article, the values of u(s), u(r) and ITV for HKED were published incorrectly in Table 6.