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Saint Petersburg, Russia

Velikoseltsev A.,Saint Petersburg Electrotechnical University | Schreiber K.U.,Bundesamt fur Kartographie und Geodasie | Yankovsky A.,Di Mendeleyev Institute For Metrology | Wells J.-P.R.,University of Canterbury | And 2 more authors.
Journal of Seismology | Year: 2012

In recent years, the measurement of rotational components of earthquake-induced ground motion became a reality due to high-resolution ring laser gyroscopes. As a consequence of the fact that they exploit the Sagnac effect, these devices are entirely insensitive to translational motion and are able to measure the rotation rate with high linearity and accuracy over a wide frequency band. During the last decade, a substantial number of earthquakes were recorded by the large ring lasers located in Germany, New Zealand, and USA, and the subsequent data analysis demonstrated reliability and consistency of the results with respect to theoretical models. However, most of the observations recorded teleseismic events in the far-field. The substantial mass and the size of these active interferometers make their near-field application difficult. Therefore, the passive counterparts of ring lasers, the fiber optic gyros can be used for seismic applications where the mobility is more important than extreme precision. These sensors provide reasonable accuracy and are small in size, which makes them perfect candidates for strong motion applications. The other advantage of fiber optic gyroscopes is that if the earthquake is local and shallow (like one occurred early this year at Canterbury, New Zealand), the large ring lasers simply do not have the dynamic range-the effect is far too large for these instruments. In this paper, we analyze a typical commercially available tactical grade fiber optic gyroscope (VG-951) with respect to the seismic rotation measurement requirements. The initial test results including translation and upper bounds of seismic rotation sensitivity are presented. The advantages and limitations of tactical grade fiber optic gyroscope as seismic rotation sensor are discussed. © 2012 Springer Science+Business Media B.V.

Antonov N.V.,Saint Petersburg State University | Gulitskiy N.M.,Di Mendeleyev Institute For Metrology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

The problem of anomalous scaling in magnetohydrodynamics turbulence is considered within the framework of the kinematic approximation, in the presence of a large-scale background magnetic field. Field theoretic renormalization group methods are applied to the Kazantsev-Kraichnan model of a passive vector advected by the Gaussian velocity field with zero mean and correlation function α δ(t-t′)/k d+ε. Inertial-range anomalous scaling for the tensor pair correlators is established as a consequence of the existence in the corresponding operator product expansions of certain "dangerous" composite operators, whose negative critical dimensions determine the anomalous exponents. The main technical result is the calculation of the anomalous exponents in the order ε 2 of the ε expansion (two-loop approximation). © 2012 Springer-Verlag.

Kadis R.,Di Mendeleyev Institute For Metrology | Leito I.,University of Tartu
Analytica Chimica Acta | Year: 2010

The residual liquid junction potential (RLJP) needs to be accounted for in pH uncertainty estimation. Attempts to do this and the currently available methods for evaluating the RLJP are critically discussed and their weak sides are pointed out. In this work an empirical approach to the problem is proposed. It is based on the use of the RLJP bias estimated on a variety of measurement conditions for a specific class of analytical objects essentially differing in ionic strength from the pH calibration buffers. The data from five independent studies, including interlaboratory comparisons, on pH measurement in low ionic strength waters were used to find the overall bias observed in the 10-4moldm-3 strong acid solution. The procedure includes quantifying the uncertainty of bias values from separate studies by combination of the relevant uncertainty components and testing the consistency of the data. The weighted mean bias in pH was found to be 0.043±0.007 (k=2). With this estimate, the pH measurement uncertainties calculated according to the previously suggested procedure (I. Leito, L. Strauss, E. Koort, V. Pihl, Accredit. Qual. Assur. 7 (2002) 242-249.) can be enlarged to take the uncorrected bias into account. The resulting uncertainties on the level of 0.10-0.14 (k=2) are obtained in this way for pH measurement in water and poorly buffered aqueous solutions in the range of pH 7.5-3.5. © 2010 Elsevier B.V.

Pokhodun A.I.,Di Mendeleyev Institute For Metrology
AIP Conference Proceedings | Year: 2013

The paper deals with results of an analysis carried out at the VNIIM with the purpose to ascertain the current status of thermometry as well as to make an attempt to determine a line of development of this field of measurements in future. The analysis was based on a survey of 150 industrial enterprises and scientific organizations. The results of the survey showed that during two last decades the accuracy of measuring instruments used in science and industry was increased almost tenfold. However, advances in the improvement of temperature measuring instruments were achieved not owing to new principles of designing thermometers, but due to rapid development of electronics, which allowed to solve the problem of accurate measurements of resistance and electromotive force and automatize measurement information processing. In most cases the contemporary measuring instruments perfectly meet the requirements to the measurement accuracy claimed by the enterprises surveyed and are provided with a necessary metrological assurance. Although there is a general understanding of the necessity to use the thermodynamic scale rather than the conditional one, we have no objective evidence with regard to how close we have to bring the international scale used in our everyday practice to the thermodynamic scale and what will be a benefit for development of science and industry. Increasing the accuracy of national standards does not affect, as a rule, the accuracy of temperature measurements in industry and scientific research since the main contribution to a total measurement error is made by components caused by an improper measurement procedure. © 2013 AIP Publishing LLC.

Milman B.L.,Di Mendeleyev Institute For Metrology | Zhurkovich I.K.,All Russia Institute of Plant Protection
Rapid Communications in Mass Spectrometry | Year: 2011

To gain perspective on building full transferable libraries of MSn spectra from their diverse/numerous collections, a new library was built from 1723 MS>1 spectra (mainlyMS2 spectra) of 490 pesticides and related compounds. Spectra acquired on different types of tandem instruments in various experimental conditions were extracted from 168 literature articles and Internet sites. Testing of the library was based on searches where 'unknown' and reference spectra originated from different sources (mainly from different laboratories) were cross-compared. The NIST 05 MS2 library was added to the reference spectra. The library searches were performed with all the test spectra or were divided into different subsamples containing (a) various numbers of replicate spectra of test compounds or (b) spectra acquired from different instrument types. Thus, the dependence of true/false search (identification) result rates on different factors was explored. The percentage of 1st rank correct identifications (true positives) for the only 'unknown' mass spectrum and two and more reference spectra and matching precursor ion m/z values was 89%. For qualified matches, above the cut-off match factor, that rate decreased to 80%. The corresponding rates based on the best match for two and more 'unknown' and reference spectral replicates were 89-94%. For quadrupole instruments, the rates were even higher: 91-95% (one 'unknown' spectrum) and 90-100% (two and more such spectra). This study shows that MS2 spectral libraries generated from the numerous literature/Internet sources are not less efficient for the goal of identification of unknown compounds including pesticides than very common EI-MS1 libraries and are almost as efficient as the most productive from current MS2 spectral databases. Such libraries may be used as individual reference databases or supplements to large experimental spectral collections covering many groups of abundant compounds and different types of tandem mass spectrometers. Copyright © 2011 John Wiley & Sons, Ltd.

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