128 results on '"A. G. Nikulin"'
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2. The impact of lateral boundary forcing in the CORDEX-Africa ensemble over southern Africa
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M. C. Karypidou, S. P. Sobolowski, L. Sangelantoni, G. Nikulin, and E. Katragkou
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Geology ,QE1-996.5 - Abstract
The region of southern Africa (SAF) is among the most exposed climate change hotspots and is projected to experience severe impacts across multiple economical and societal sectors. For this reason, producing reliable projections of the expected impacts of climate change is key for local communities. In this work we use an ensemble of 19 regional climate model (RCM) simulations performed in the context of the Coordinated Regional Climate Downscaling Experiment (CORDEX) – Africa and a set of 10 global climate models (GCMs) participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) that were used as the driving GCMs in the RCM simulations. We are concerned about the degree to which RCM simulations are influenced by their driving GCMs, with regards to monthly precipitation climatologies, precipitation biases and precipitation change signal, according to the Representative Concentration Pathway (RCP) 8.5 for the end of the 21st century. We investigate the degree to which RCMs and GCMs are able to reproduce specific climatic features over SAF and over three sub-regions, namely the greater Angola region, the greater Mozambique region, and the greater South Africa region. We identify that during the beginning of the rainy season, when regional processes are largely dependent on the coupling between the surface and the atmosphere, the impact of the driving GCMs on the RCMs is smaller compared to the core of the rainy season, when precipitation is mainly controlled by the large-scale circulation. In addition, we show that RCMs are able to counteract the bias received by their driving GCMs; hence, we claim that the cascade of uncertainty over SAF is not additive, but indeed the RCMs do provide improved precipitation climatologies. The fact that certain bias patterns during the historical period (1985–2005) identified in GCMs are resolved in RCMs provides evidence that RCMs are reliable tools for climate change impact studies over SAF.
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- 2023
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3. The impact of regional climate model formulation and resolution on simulated precipitation in Africa
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M. Wu, G. Nikulin, E. Kjellström, D. Belušić, C. Jones, and D. Lindstedt
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Science ,Geology ,QE1-996.5 ,Dynamic and structural geology ,QE500-639.5 - Abstract
We investigate the impact of model formulation and horizontal resolution on the ability of Regional Climate Models (RCMs) to simulate precipitation in Africa. Two RCMs (SMHI-RCA4 and HCLIM38-ALADIN) are utilized for downscaling the ERA-Interim reanalysis over Africa at four different resolutions: 25, 50, 100, and 200 km. In addition to the two RCMs, two different parameter settings (configurations) of the same RCA4 are used. By contrasting different downscaling experiments, it is found that model formulation has the primary control over many aspects of the precipitation climatology in Africa. Patterns of spatial biases in seasonal mean precipitation are mostly defined by model formulation, while the magnitude of the biases is controlled by resolution. In a similar way, the phase of the diurnal cycle in precipitation is completely controlled by model formulation (convection scheme), while its amplitude is a function of resolution. However, the impact of higher resolution on the time-mean climate is mixed. An improvement in one region/season (e.g. reduction in dry biases) often corresponds to a deterioration in another region/season (e.g. amplification of wet biases). At the same time, higher resolution leads to a more realistic distribution of daily precipitation. Consequently, even if the time-mean climate is not always greatly sensitive to resolution, the realism of the simulated precipitation increases as resolution increases. Our results show that improvements in the ability of RCMs to simulate precipitation in Africa compared to their driving reanalysis in many cases are simply related to model formulation and not necessarily to higher resolution. Such model formulation related improvements are strongly model dependent and can, in general, not be considered as an added value of downscaling.
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- 2020
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4. On the contribution of internal climate variability to European future climate trends
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T. Koenigk, L. Bärring, D. Matei, G. Nikulin, G. Strandberg, E. Tyrlis, S. Wang, and R. Wilcke
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internal climate variability ,european future climate trends ,uncertainties of trends ,variability in southern sweden ,large ensemble global model simulations ,Oceanography ,GC1-1581 ,Meteorology. Climatology ,QC851-999 - Abstract
Large historical and future ensemble simulations from the Max-Planck Institute and the Canadian Earth System Models and from CMIP5 have been analysed to investigate the uncertainty due to internal variability in multi-decadal temperature and precipitation trends over Europe. Internal variability dominates the uncertainties in temperature and precipitation trends in all seasons at 30-year time scales. Locally, seasonal 30-year temperature trends deviate up to ±3 °C from the ensemble mean trend. Thus, in the entire of Europe, local seasonal temperature changes until year 2050 from below −1 °C up to more than 4 °C are possible according to the model results. Up to 30% of all ensemble members show negative temperature trends until year 2050 in winter, up to 10% of the members in summer. Uncertainties of 30-year precipitation trends due to internal variability exceed the trends almost everywhere in Europe. Only in few European regions more than 75% of the members agree on the sign of the change until year 2050. In southern Sweden, minimum and maximum winter (summer) temperature trends in the next 30 years differ with up to 7 °C (5 °C) between individual members of the large model ensembles. Large positive temperature trends are linked to positive (negative) precipitation trends in winter (summer) in southern Sweden. This variability is attributed to the variability in large scale atmospheric circulation trends, mainly due to internal atmospheric variability. We find only weak linkages between the variability of temperature trends and the dominant decadal to multi-decadal climate modes. This indicates that there is limited potential to predict the multi-decadal variability in climate trends. The main findings from our study are robust across the large ensembles from the different models used in this study but at the local scale, the results depend also on the choice of the model.
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- 2020
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5. The development of methods and instruments for thermal conductivity measurement of standard core samples for petrophysical studies
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B. V. Grigorev, S. G. Nikulin, D. A. Vazhenin, and D. V. Vakhnina
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General Medicine - Published
- 2023
6. Monitoring of the Essential Climate Variables of the Atmosphere from Satellite-based Infrared Sounder IKFS-2
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A. B. Uspensky, A. N. Rublev, D. A. Kozlov, V. V. Golomolzin, Yu. V. Kiseleva, I. A. Kozlov, and A. G. Nikulin
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Fluid Flow and Transfer Processes ,Atmospheric Science ,Water Science and Technology - Published
- 2022
7. European climate change at global mean temperature increases of 1.5 and 2 °C above pre-industrial conditions as simulated by the EURO-CORDEX regional climate models
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E. Kjellström, G. Nikulin, G. Strandberg, O. B. Christensen, D. Jacob, K. Keuler, G. Lenderink, E. van Meijgaard, C. Schär, S. Somot, S. L. Sørland, C. Teichmann, and R. Vautard
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Science ,Geology ,QE1-996.5 ,Dynamic and structural geology ,QE500-639.5 - Abstract
We investigate European regional climate change for time periods when the global mean temperature has increased by 1.5 and 2 °C compared to pre-industrial conditions. Results are based on regional downscaling of transient climate change simulations for the 21st century with global climate models (GCMs) from the fifth-phase Coupled Model Intercomparison Project (CMIP5). We use an ensemble of EURO-CORDEX high-resolution regional climate model (RCM) simulations undertaken at a computational grid of 12.5 km horizontal resolution covering Europe. The ensemble consists of a range of RCMs that have been used for downscaling different GCMs under the RCP8.5 forcing scenario. The results indicate considerable near-surface warming already at the lower 1.5 °C of warming. Regional warming exceeds that of the global mean in most parts of Europe, being the strongest in the northernmost parts of Europe in winter and in the southernmost parts of Europe together with parts of Scandinavia in summer. Changes in precipitation, which are less robust than the ones in temperature, include increases in the north and decreases in the south with a borderline that migrates from a northerly position in summer to a southerly one in winter. Some of these changes are already seen at 1.5 °C of warming but are larger and more robust at 2 °C. Changes in near-surface wind speed are associated with a large spread among individual ensemble members at both warming levels. Relatively large areas over the North Atlantic and some parts of the continent show decreasing wind speed while some ocean areas in the far north show increasing wind speed. The changes in temperature, precipitation and wind speed are shown to be modified by changes in mean sea level pressure, indicating a strong relationship with the large-scale circulation and its internal variability on decade-long timescales. By comparing to a larger ensemble of CMIP5 GCMs we find that the RCMs can alter the results, leading either to attenuation or amplification of the climate change signal in the underlying GCMs. We find that the RCMs tend to produce less warming and more precipitation (or less drying) in many areas in both winter and summer.
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- 2018
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8. Development of the concept of a multiphase flow meter
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N. A. Shulaev, S. G. Nikulin, R. B. Aubakirov, Ja. V. Puritskis, and K. A. Motaev
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Anesthesiology and Pain Medicine - Abstract
In the oil and gas industry, several problems can be identified that affect the subsequent rates of development of the relevant industry: low quality of oil products and low rates of application of new technologies, which directly slows down the country's economic component. Currently, the development of multiphase flow meters is underway, however, the creation of a universal device is still an unsolved problem, and the existing developments require calibrations. The main problem in calculating the flow rate of the fluid is the determination of the density of the components of the passing mixture. The use of X-ray radiation allows you to solve most of the technical problems, as well as to determine the density with a high accuracy. Flow meters using this concept are of little use. The purpose of the study of our work is to update the applicability of the use of the X-ray range in determining the density of the passing flow. In the course of the work, a search and analysis of tabular data characterizing the interaction of radiation with matter was carried out, according to the results of which acceptable sources of characteristic radiation were determined. In the next step, we modeled the structure of the fluid and derived a system of equations that allows one to determine the densities using existing instruments, as well as constants that are determined experimentally. The result of the research is a solvable system of equations, as well as primary modeling and determination of the component, quantitative composition of the gas-liquid mixture under consideration in laminar flow. The result of this work is to obtain a theoretical confirmation of the relevance of using the device based on this concept, the subsequent addition of characteristic radiation detectors will also help to determine the chemical composition of the fluid.
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- 2022
9. WCRP COordinated Regional Downscaling EXperiment (CORDEX): a diagnostic MIP for CMIP6
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W. J. Gutowski Jr., F. Giorgi, B. Timbal, A. Frigon, D. Jacob, H.-S. Kang, K. Raghavan, B. Lee, C. Lennard, G. Nikulin, E. O'Rourke, M. Rixen, S. Solman, T. Stephenson, and F. Tangang
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Geology ,QE1-996.5 - Abstract
The COordinated Regional Downscaling EXperiment (CORDEX) is a diagnostic model intercomparison project (MIP) in CMIP6. CORDEX builds on a foundation of previous downscaling intercomparison projects to provide a common framework for downscaling activities around the world. The CORDEX Regional Challenges provide a focus for downscaling research and a basis for making use of CMIP6 global climate model (GCM) output to produce downscaled projected changes in regional climates and assess sources of uncertainties in the projections, all of which can potentially be distilled into climate change information for vulnerability, impacts and adaptation studies. CORDEX Flagship Pilot Studies advance regional downscaling by targeting one or more of the CORDEX Regional Challenges. A CORDEX-CORE framework is planned that will produce a baseline set of homogeneous high-resolution, downscaled projections for regions worldwide. In CMIP6, CORDEX coordinates with ScenarioMIP and is structured to allow cross comparisons with HighResMIP and interaction with the CMIP6 VIACS Advisory Board.
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- 2016
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10. Metallurgical Features of Plasma Surfacing Repair of Magnesium Alloys
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R. G. Nikulin, Yu. D. Shchitsyn, E. A. Krivonosova, D. S. Zagrebin, and T. Hassel
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Mechanics of Materials ,Materials Chemistry ,Metals and Alloys ,Condensed Matter Physics - Published
- 2022
11. Characteristics of Structure and Properties of Magnesium Alloys during Plasma Additive Deposition
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Yu. D. Shchitsyn, E. A. Krivonosova, S. D. Neulybin, R. G. Nikulin, T. Hassel, and D. N. Trushnikov
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Mechanics of Materials ,General Materials Science ,Surfaces and Interfaces ,Condensed Matter Physics - Published
- 2021
12. Application of plasma surfacing for additive manufacturing of magnesium alloy workpieces
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E. A. Krivonosova, R. G. Nikulin, Yu. D. Shchitsyn, and T. V. Ol’shanskaya
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Materials science ,Metallurgy ,Materials Chemistry ,Metals and Alloys ,Ceramics and Composites ,Plasma ,Physical and Theoretical Chemistry ,Magnesium alloy ,Condensed Matter Physics ,Surfaces, Coatings and Films - Published
- 2021
13. Influence of the Current Frequency in Pulsed Plasma Surfacing on the Strength of High-Alloy Steel in Additive Technology
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T. V. Ol’shanskaya, S. D. Neulybin, R. G. Nikulin, Yu. D. Shchitsyn, and A. Yu. Dushina
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Materials science ,Mechanical Engineering ,Product (mathematics) ,Alloy steel ,engineering ,Plasma ,engineering.material ,Current (fluid) ,Composite material ,Industrial and Manufacturing Engineering - Abstract
The influence of pulsed current on the additive manufacture of high-alloy 308LSi steel is investigated. Frequencies of 5000 Hz or more have the greatest influence on the structure and properties. In the absence of pulses, the mechanical properties of the printed product correspond to those of steel produced by standard technology, whereas current pulses increase the strength by 15–20%.
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- 2021
14. DEVELOPMENT OF A FIELD MOBILE STANDARD OF THE 2ND CATEGORY AS A TOOL FOR VERIFYING WELL PRODUCTION MEASURING EQUIPMENT
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Sergey G. Nikulin, Andrej A. Stupnikov, and Vladimir Evgenyevich Vershinin
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Development (topology) ,Field (physics) ,020209 energy ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Systems engineering ,Environmental science ,Production (economics) ,02 engineering and technology ,010301 acoustics ,01 natural sciences ,Microbiology ,Measuring equipment - Abstract
In recent years, in the oil production industry there is a tendency of mass use of stationary multiphase metering units for determining oil, water, and associated gas flow rates in the recoverable well production. Automated group metering units, allowing to cover the whole group of wells in rotation metering mode, became widespread. The necessity of equipping wells with individual or group measuring devices is dictated, first of all, by the economic tasks of improving oil recovery factor and production optimization. In these conditions, the task of periodic verification of stationary measuring devices in the field with the help of mobile standards-measuring devices of higher accuracy class becomes urgent. The standard’s mobility and the need to work in the field with fluids of different composition significantly complicates the task of creating such a device. The practicality and economy of the created units first of all depends on a choice of a measuring method determining the design of the unit. This article analyzes the existing types of equipment for measuring oil, gas, and water consumption at the oil production wells. Showing the main advantages and disadvantages of each of them, this paper proves the necessity of using complex solutions based on different physical principles to improve the accuracy of measurements. The authors have proposed a combined scheme of a mobile standard of the 2nd category with a dynamic method for measuring the phase rates at the core. The unit performs a multi-stage partial separation of the input multiphase flow into liquid and gas phases and determines the fractions of water and oil in the liquid stream using a hydrostatic-type mixture composition analyzer. In addition, this article indicates the ways of increasing the accuracy of the measuring installation.
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- 2021
15. European daily precipitation according to EURO-CORDEX regional climate models (RCMs) and high-resolution global climate models (GCMs) from the High-Resolution Model Intercomparison Project (HighResMIP)
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M.-E. Demory, S. Berthou, J. Fernández, S. L. Sørland, R. Brogli, M. J. Roberts, U. Beyerle, J. Seddon, R. Haarsma, C. Schär, E. Buonomo, O. B. Christensen, J. M. Ciarlo ̀, R. Fealy, G. Nikulin, D. Peano, D. Putrasahan, C. D. Roberts, R. Senan, C. Steger, C. Teichmann, and R. Vautard
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lcsh:Geology ,lcsh:QE1-996.5 - Abstract
In this study, we evaluate a set of high-resolution (25–50 km horizontal grid spacing) global climate models (GCMs) from the High-Resolution Model Intercomparison Project (HighResMIP), developed as part of the EU-funded PRIMAVERA (Process-based climate simulation: Advances in high resolution modelling and European climate risk assessment) project, and from the EURO-CORDEX (Coordinated Regional Climate Downscaling Experiment) regional climate models (RCMs) (12–50 km horizontal grid spacing) over a European domain. It is the first time that an assessment of regional climate information using ensembles of both GCMs and RCMs at similar horizontal resolutions has been possible. The focus of the evaluation is on the distribution of daily precipitation at a 50 km scale under current climate conditions. Both the GCM and RCM ensembles are evaluated against high-quality gridded observations in terms of spatial resolution and station density. We show that both ensembles outperform GCMs from the 5th Coupled Model Intercomparison Project (CMIP5), which cannot capture the regional-scale precipitation distribution properly because of their coarse resolutions. PRIMAVERA GCMs generally simulate precipitation distributions within the range of EURO-CORDEX RCMs. Both ensembles perform better in summer and autumn in most European regions but tend to overestimate precipitation in winter and spring. PRIMAVERA shows improvements in the latter by reducing moderate-precipitation rate biases over central and western Europe. The spatial distribution of mean precipitation is also improved in PRIMAVERA. Finally, heavy precipitation simulated by PRIMAVERA agrees better with observations in most regions and seasons, while CORDEX overestimates precipitation extremes. However, uncertainty exists in the observations due to a potential undercatch error, especially during heavy-precipitation events. The analyses also confirm previous findings that, although the spatial representation of precipitation is improved, the effect of increasing resolution from 50 to 12 km horizontal grid spacing in EURO-CORDEX daily precipitation distributions is, in comparison, small in most regions and seasons outside mountainous regions and coastal regions. Our results show that both high-resolution GCMs and CORDEX RCMs provide adequate information to end users at a 50 km scale.
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- 2020
16. A comparative study of the major sudden stratospheric warmings in the Arctic winters 2003/2004–2009/2010
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G. Nikulin and J. Kuttippurath
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
We present an analysis of the major sudden stratospheric warmings (SSWs) in the Arctic winters 2003/04–2009/10. There were 6 major SSWs (major warmings [MWs]) in 6 out of the 7 winters, in which the MWs of 2003/04, 2005/06, and 2008/09 were in January and those of 2006/07, 2007/08, and 2009/10 were in February. Although the winter 2009/10 was relatively cold from mid-December to mid-January, strong wave 1 activity led to a MW in early February, for which the largest momentum flux among the winters was estimated at 60° N/10 hPa, about 450 m2 s−2. The strongest MW, however, was observed in 2008/09 and the weakest in 2006/07. The MW in 2008/09 was triggered by intense wave 2 activity and was a vortex split event. In contrast, strong wave 1 activity led to the MWs of other winters and were vortex displacement events. Large amounts of Eliassen-Palm (EP) and wave 1/2 EP fluxes (about 2–4 ×105 kg s−2) are estimated shortly before the MWs at 100 hPa averaged over 45–75° N in all winters, suggesting profound tropospheric forcing for the MWs. We observe an increase in the occurrence of MWs (~1.1 MWs/winter) in recent years (1998/99–2009/10), as there were 13 MWs in the 12 Arctic winters, although the long-term average (1957/58–2009/10) of the frequency stays around its historical value (~0.7 MWs/winter), consistent with the findings of previous studies. An analysis of the chemical ozone loss in the past 17 Arctic winters (1993/94–2009/10) suggests that the loss is inversely proportional to the intensity and timing of MWs in each winter, where early (December–January) MWs lead to minimal ozone loss. Therefore, this high frequency of MWs in recent Arctic winters has significant implications for stratospheric ozone trends in the northern hemisphere.
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- 2012
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17. Record-breaking ozone loss in the Arctic winter 2010/2011: comparison with 1996/1997
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J. Kuttippurath, S. Godin-Beekmann, F. Lefèvre, G. Nikulin, M. L. Santee, and L. Froidevaux
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
We present a detailed discussion of the chemical and dynamical processes in the Arctic winters 1996/1997 and 2010/2011 with high resolution chemical transport model (CTM) simulations and space-based observations. In the Arctic winter 2010/2011, the lower stratospheric minimum temperatures were below 195 K for a record period of time, from December to mid-April, and a strong and stable vortex was present during that period. Simulations with the Mimosa-Chim CTM show that the chemical ozone loss started in early January and progressed slowly to 1 ppmv (parts per million by volume) by late February. The loss intensified by early March and reached a record maximum of ~2.4 ppmv in the late March–early April period over a broad altitude range of 450–550 K. This coincides with elevated ozone loss rates of 2–4 ppbv sh−1 (parts per billion by volume/sunlit hour) and a contribution of about 30–55% and 30–35% from the ClO-ClO and ClO-BrO cycles, respectively, in late February and March. In addition, a contribution of 30–50% from the HOx cycle is also estimated in April. We also estimate a loss of about 0.7–1.2 ppmv contributed (75%) by the NOx cycle at 550–700 K. The ozone loss estimated in the partial column range of 350–550 K exhibits a record value of ~148 DU (Dobson Unit). This is the largest ozone loss ever estimated in the Arctic and is consistent with the remarkable chlorine activation and strong denitrification (40–50%) during the winter, as the modeled ClO shows ~1.8 ppbv in early January and ~1 ppbv in March at 450–550 K. These model results are in excellent agreement with those found from the Aura Microwave Limb Sounder observations. Our analyses also show that the ozone loss in 2010/2011 is close to that found in some Antarctic winters, for the first time in the observed history. Though the winter 1996/1997 was also very cold in March–April, the temperatures were higher in December–February, and, therefore, chlorine activation was moderate and ozone loss was average with about 1.2 ppmv at 475–550 K or 42 DU at 350–550 K, as diagnosed from the model simulations and measurements.
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- 2012
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18. On the time-scales of the downward propagation and of the tropospheric planetary wave response to the stratospheric circulation
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G. Nikulin and F. Lott
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Science ,Physics ,QC1-999 ,Geophysics. Cosmic physics ,QC801-809 - Abstract
Three datasets (the NCEP-NCAR reanalysis, the ERA-40 reanalysis and the LMDz-GCM), are used to analyze the relationships between large-scale dynamics of the stratosphere and the tropospheric planetary waves during the Northern Hemisphere (NH) winter. First, a cross-spectral analysis clarifies the time scales at which downward propagation of stratospheric anomalies occurs in the low-frequency band (that is at periods longer than 50 days). At these periods the strength of the polar vortex, measured by the 20-hPa Northern Annular Mode (NAM) index and the wave activity flux, measured by the vertical component of the Eliassen-Palm flux (EPz) from both the troposphere and the stratosphere, are significantly related with each other and in lead-lag quadrature. While, in the low-frequency band of the downward propagation, the EPz anomalies of the opposite sign around NAM extremes drive the onset and decay of NAM events, we found that the EPz anomalies in the troposphere, are significantly larger after stratospheric vortex anomalies than at any time before. This marked difference in the troposphere is related to planetary waves with zonal wavenumbers 1–3, showing that there is a tropospheric planetary wave response to the earlier state of the stratosphere at low frequencies. We also find that this effect is due to anomalies in the EPz issued from the northern midlatitudes and polar regions.
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- 2010
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19. On the need for regional climate information over Africa under varying levels of global warming
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C J Lennard, G Nikulin, A Dosio, and W Moufouma-Okia
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CORDEX ,regional modelling ,regional information ,global warming levels ,Environmental technology. Sanitary engineering ,TD1-1066 ,Environmental sciences ,GE1-350 ,Science ,Physics ,QC1-999 - Abstract
The Paris Agreement of COP21 set a goal of holding global average temperature increases to below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C. This is particularly relevant for the African context where temperatures are likely to warm faster than the global average and where the magnitude of change will be regionally heterogeneous. Additionally, many biogeophysical and socioeconomic systems are particularly vulnerable to change in both means and extremes. In this paper we contextualise the lack of regional climate information over Africa at global warming levels (GWLs) of 1.5 and 2 °C above pre-industrial levels through a short review of the literature. We show most studies that provide information over Africa under specific GWLs have used data from global models, however global models poorly resolve local scale forcing (e.g. topography) nor the internal climate variability of a region. Although downscaling using regional climate models can address these issues we find only one paper that has used downscaled data for GWL studies over Africa. Articles in this focus collection use data from global climate models and the co-ordinated regional downscaling experiment to elucidate the regional and local scale climate responses to various warming levels. This may provide information that contributes meaningfully to the UNFCCC negotiation process and also for the development of adaptation and mitigation policies.
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- 2018
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20. The southern African climate under 1.5 °C and 2 °C of global warming as simulated by CORDEX regional climate models
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G Maúre, I Pinto, M Ndebele-Murisa, M Muthige, C Lennard, G Nikulin, A Dosio, and A Meque
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climate change ,global warming levels ,regional climate model projection ,Southern Africa ,Environmental technology. Sanitary engineering ,TD1-1066 ,Environmental sciences ,GE1-350 ,Science ,Physics ,QC1-999 - Abstract
Results from an 25 regional climate model simulations from the Coordinated Regional Downscaling Experiment Africa initiative are used to assess the projected changes in temperature and precipitation over southern Africa at two global warming levels (GWLs), namely 1.5 °C and 2.0 °C, relative to pre-industrial values, under the Representative Concentration Pathway 8.5. The results show a robust increase in temperature compared to the control period (1971–2000) ranging from 0.5 °C–1.5 °C for the 1.5 °C GWL and from 1.5 °C–2.5 °C, for the 2.0 °C GWL. Areas in the south-western region of the subcontinent, covering South Africa and parts of Namibia and Botswana are projected to experience the largest increase in temperature, which are greater than the global mean warming, particularly during the September–October–November season. On the other hand, under 1.5 °C GWL, models exhibit a robust reduction in precipitation of up to 0.4 mm day ^−1 (roughly 20% of the climatological values) over the Limpopo Basin and smaller areas of the Zambezi Basin in Zambia, and also parts of Western Cape, South Africa. Models project precipitation increase of up to 0.1 mm day ^−1 over central and western South Africa and in southern Namibia. Under 2.0 °C GWL, a larger fraction of land is projected to face robust decreases between 0.2 and 0.4 mm day ^−1 (around 10%–20% of the climatological values) over most of the central subcontinent and parts of western South Africa and northern Mozambique. Decreases in precipitation are accompanied by increases in the number of consecutive dry days and decreases in consecutive wet days over the region. The importance of achieving the Paris Agreement is imperative for southern Africa as the projected changes under both the 1.5 °C, and more so, 2.0 °C GWL imply significant potential risks to agricultural and economic productivity, human and ecological systems health and water resources with implied increase in regional water stresses.
- Published
- 2018
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21. The mean meridional circulation and midlatitude ozone buildup
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G. Nikulin and A. Karpechko
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The wintertime ozone buildup over the Northern Hemisphere (NH) midlatitudes and its connection with the mean meridional circulation in the stratosphere are examined statistically on a monthly basis from October to March (1980–2002). The ozone buildup begins locally in October with positive total ozone tendencies over the North Pacific, which spread eastward and westward in November and finally cover all midlatitudes in December. The local onset of the buildup in October is not evident in zonal mean ozone tendency, which is close to zero. From November to March, zonal mean total ozone tendency (50°–60° N) shows a strong correlation (|r|=0.7) with several zonal mean parameters associated to the mean meridional circulation, namely: eddy heat flux, temperature tendency, the vertical residual velocity and the residual streamfunction. At the same time, on the latitude-altitude cross section, correlation patterns between ozone tendency and widely used eddy heat flux are not uniform during winter. The strongest correlations are located equatorward (almost throughout the stratosphere) or poleward (only in the lower stratosphere) of the edge of the polar vortex. Such distribution may depend on the existence of the midlatitude and polar waveguides which defined refraction of upward propagating waves from the troposphere either to the midlatitude stratosphere or to the polar stratosphere. As a consequence of the nonuniform correlation patterns, heat flux averaged over the common region 45°–75° N, 100 hPa is not always an optimum proxy for statistical models describing total ozone variability in midlatitudes. Other parameters approximating the strength of the mean meridional circulation have more uniform and stable correlation patterns with ozone tendency during winter. We show that the NH midlatitude ozone buildup has a stable statistical relationship with the mean meridional circulation in all months from October to March and half of the interannual variability in monthly ozone tendencies can be explained by applying different proxies of the mean meridional circulation.
- Published
- 2005
22. The IKFS-2 Infrared Fourier-Transform Spectrometer Operating Onboard the Meteor-M No.2 Satellite
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A. G. Nikulin, D. A. Kozlov, D. O. Monakhov, I.A. Kozlov, A. V. Kukharsky, Yu. M. Golovin, A. N. Rublev, F. S. Zavelevich, and A. B. Uspensky
- Subjects
Meteor (satellite) ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Infrared ,Design specification ,0211 other engineering and technologies ,Fourier transform spectrometers ,02 engineering and technology ,Oceanography ,01 natural sciences ,Atmosphere ,Environmental science ,Satellite ,Meteorological satellite ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Remote sensing - Abstract
The results of the commissioning of the IKFS-2 instrument and its subsequent operation onboard the Meteor-M no. 2 polar orbiting meteorological satellite are presented. Comparison of the IKFS-2 data with independent satellite measurements shows that its performance characteristics are in accordance with the design specification. It is therefore possible to realize the IKFS-2 mission objectives for obtaining data on the meteorological parameters and composition of the atmosphere.
- Published
- 2018
23. Correction of casting defects in aluminum alloys using plasma welding
- Author
-
Yu D. Schitsyn, T. V. Olshanskaya, R. G. Nikulin, M. V. Pichkalev, and Dmitry Belinin
- Subjects
Plasma arc welding ,Materials science ,chemistry ,Casting (metalworking) ,Aluminium ,Metallurgy ,chemistry.chemical_element - Published
- 2021
24. HCLIM38: a flexible regional climate model applicable for different climate zones from coarse to convection-permitting scales
- Author
-
D. Belušić, H. de Vries, A. Dobler, O. Landgren, P. Lind, D. Lindstedt, R. A. Pedersen, J. C. Sánchez-Perrino, E. Toivonen, B. van Ulft, F. Wang, U. Andrae, Y. Batrak, E. Kjellström, G. Lenderink, G. Nikulin, J.-P. Pietikäinen, E. Rodríguez-Camino, P. Samuelsson, E. van Meijgaard, and M. Wu
- Subjects
Convection ,Climate zones ,Atmospheric physics ,Climate Research ,010504 meteorology & atmospheric sciences ,Meteorology ,lcsh:QE1-996.5 ,0207 environmental engineering ,Numerical weather prediction ,02 engineering and technology ,01 natural sciences ,Klimatforskning ,lcsh:Geology ,13. Climate action ,Environmental science ,Climate model ,Model development ,020701 environmental engineering ,HCLIM ,Regional climate modelling system ,0105 earth and related environmental sciences ,Regional climate models - Abstract
This paper presents a new version of HCLIM, a regional climate modelling system based on the ALADIN–HIRLAM numerical weather prediction (NWP) system. HCLIM uses atmospheric physics packages from three NWP model configurations, HARMONIE–AROME, ALARO and ALADIN, which are designed for use at different horizontal resolutions. The main focus of HCLIM is convection-permitting climate modelling, i.e. developing the climate version of HARMONIE–AROME. In HCLIM, the ALADIN and ALARO configurations are used for coarser resolutions at which convection needs to be parameterized. Here we describe the structure and development of the current recommended HCLIM version, cycle 38. We also present some aspects of the model performance. HCLIM38 is a new system for regional climate modelling, and it is being used in a number of national and international projects over different domains and climates ranging from equatorial to polar regions. Our initial evaluation indicates that HCLIM38 is applicable in different conditions and provides satisfactory results without additional region-specific tuning. HCLIM is developed by a consortium of national meteorological institutes in close collaboration with the ALADIN–HIRLAM NWP model development. While the current HCLIM cycle has considerable differences in model setup compared to the NWP version (primarily in the description of the surface), it is planned for the next cycle release that the two versions will use a very similar setup. This will ensure a feasible and timely climate model development as well as updates in the future and provide an evaluation of long-term model biases to both NWP and climate model developers. This research has been supported by Horizon 2020 (EUCP (grant no. 776613)) and the Maj and Tor Nessling foundation.
- Published
- 2020
25. IR-Method for Determining the Water Contents in a Water-Oil Emulsion Flow
- Author
-
Evgeny V. Zaitsev, Anatoly N. Shuvaev, and Sergey G. Nikulin
- Subjects
Materials science ,Chemical engineering ,020209 energy ,0103 physical sciences ,Flow (psychology) ,0202 electrical engineering, electronic engineering, information engineering ,02 engineering and technology ,010301 acoustics ,01 natural sciences ,Water oil emulsion - Published
- 2018
26. Application of Absorption NIR Spectroscopy in Multiphase Flow Measurement
- Author
-
Lyudmila A. Puldas, Evgeny V. Zaytsev, and Sergey G. Nikulin
- Subjects
Materials science ,Multiphase flow ,Near-infrared spectroscopy ,Analytical chemistry ,Absorption (electromagnetic radiation) - Published
- 2016
27. Hyperspectral infrared atmospheric sounder IKFS-2 on 'Meteor-M' No. 2 – Four years in orbit
- Author
-
Alexander V. Polyakov, F. S. Zavelevich, D. A. Kozlov, Yana Virolainen, A. N. Rublev, I.A. Kozlov, Y. M. Timofeyev, V. P. Pyatkin, E. V. Rusin, A. V. Kukharsky, J.V. Kiseleva, A. B. Uspensky, and A. G. Nikulin
- Subjects
Radiation ,Infrared ,Calibration ,Radiance ,Environmental science ,Hyperspectral imaging ,Satellite ,Spectral resolution ,Spectroscopy ,Atomic and Molecular Physics, and Optics ,Spectral line ,Trace gas ,Remote sensing - Abstract
The first Russian advanced infrared (IR) atmospheric sounder IKFS-2 was launched in July 2014 on the “Meteor-M” No. 2 meteorological satellite. It is planned that this instrument and similar devices will continue to operate until 2025 aboard the current and subsequent satellites of “Meteor-M” series. IKFS-2 is a Fourier transform spectrometer covering the spectral domain of 5–15 µm. It belongs to a class of hyperspectral IR sounders, designed to measure the outgoing IR radiance spectra and to provide information on the thermodynamic parameters and the composition of the atmosphere such as vertical temperature and humidity profiles, estimates of the ozone and other trace gases total column amounts. In the paper, the IKFS-2 operation on board “Meteor-M” No. 2 is analyzed, including the assessment of the measurements’ quality (the errors of radiometric and spectral calibration) and their information content. Since launch, the instrument performance has been remained stable, and the actual IKFS-2 characteristics (threshold value of NESR, uncertainty of onboard radiometric and spectral calibrations, spectral resolution) meet the planned requirements. There is a good agreement between IKFS-2 measurements and measurements of independent satellite instruments (SEVIRI, IASI). The paper also provides an overview of the developed scientific basis for simulation and interpretation (“inversion”) of satellite measurements. The examples of output IKFS-2 level 2 products (vertical profiles of temperature and humidity, total ozone content) are given together with the error analysis. The performance of atmospheric (temperature and humidity) profile retrievals and the feasibility of total ozone content estimates are evaluated by comparison with independent ground-based or satellite measurements.
- Published
- 2019
28. Psikhologo-pedagogicheskoe soprovozhdenie uchebno-trenirovochnogo protsessa bokserov 10-12 let na etape nachal'noi podgotovki
- Author
-
Klim V. Gaptrofekov, Ruslan R. Gafurov, Roman D. Nikulin, and Dmitrii G. Nikulin
- Subjects
анализ ,психологическая подготовка ,тренировочный процесс ,исследование ,начальная подготовка - Abstract
Статья посвящена изучению психофизических характеристик боксеров на начальном этапе, совершенствованию сохранения контингента спортсменов на более высоком уровне.
- Published
- 2017
29. A Scientific-Experimental Unit for Testing Multiphase Flows
- Author
-
A. N. Lishchuk, V. V. Kotlov, E. V. Golubev, S. G. Nikulin, N. B. Filippova, and A. A. Vakulin
- Subjects
Engineering ,Fuel Technology ,Petroleum engineering ,Geochemistry and Petrology ,business.industry ,General Chemical Engineering ,Energy Engineering and Power Technology ,Process control ,Experimental Unit ,Control engineering ,business ,Flow measurement - Abstract
A scientific-experimental unit built by GMS Neftemash (Tyumen) in collaboration with the Tyumen State University for testing multiphase flows is described. This flow-type unit allows development, testing, and checking of multiphase flowmeters.
- Published
- 2015
30. The Infrared Method of Determining The Water-Cut of a Nonhomogeneous Water-Gaz-Oil Stream
- Author
-
B. V. Grigoriev, S. G. Nikulin, P. Y. Mikhailov, and E. V. Zaitcev
- Subjects
Materials science ,Water cut ,Infrared ,Mineralogy - Abstract
A perspective method of water cut determination the for water-oil flux based on the optical measurement method using NIR spectrometry is considered in this paper. The laboratory studies on the implementation of the method on a double-beam NIR spectrometer have been carried out. Water-oil emulsions with different moisture contents have been used as test specimen. Optimal ranges of wavelengths to analyze the emulsion composition at different thicknesses of a translucent mixture have been determined. It has been shown that an optical path length has a significant influence on the choice of operating wavelength ranges. It has been found that the dispersion value in a water-oil emulsion is a key factor for the accuracy of measurements. A calculation method describing absorption and scattering of NIR radiation by water/oil emulsions has been proposed. The comparison of calculated and experimental data has been carried out. The possibility of the presented calculation method application for analysis of water cut of a water-oil emulsion has been proved.
- Published
- 2016
31. Impact of ocean-atmosphere coupling and high resolution on the simulation of medicanes over the Mediterranean Sea: multi-model analysis with Med-CORDEX and EURO-CORDEX runs
- Author
-
Gaertner M. A., J. J. Gonzalez-Aleman, R. Romera, M. Dominguez, V. Gil, E. Sanchez, C. Gallardo, M. M. Miglietta, K. Walsh, D. Sein, S. Somot, A. dell'Aquila, B. Ahrens, A. Colette, S. Bastin, E. van Meijgaard, G. Nikulin, Instituto de Ciencias Ambientales [Toledo] (ICAM), Universidad de Castilla-La Mancha (UCLM), Institute of Environmental Sciences/ Instituto de Ciencias Medioambientales de Toledo (ICAM), Istituto di Scienze dell'Atmosfera e del Clima (ISAC), Consiglio Nazionale delle Ricerche [Roma] (CNR), University of Melbourne, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile (ENEA), Institut für Atmosphäre und Umwelt [Frankfurt/Main] (IAU), Goethe-Universität Frankfurt am Main, Institut National de l'Environnement Industriel et des Risques (INERIS), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Royal Netherlands Meteorological Institute (KNMI), Rossby Centre, SMHI, Norrköping, 601 76, Sweden, Swedish Meteorological and Hydrological Institute (SMHI), Universidad de Castilla-La Mancha = University of Castilla-La Mancha (UCLM), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile = Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA)
- Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] ,Medicanes - Abstract
International audience; Medicanes are cyclones over the Mediterranean Sea having a tropical structure and a rather small size, for which the sea-atmosphere interaction plays a fundamental role. High resolution and ocean-atmosphere coupled RCM simulations performed in MedCORDEX and EURO-CORDEX projects are used to analyze the ability of RCMs to represent the observed characteristics of medicanes, and the impact of increasing resolution and using air-sea coupling on its simulation. An observational database based on satellite images combined with very high resolution simulations (Miglietta et al. 2013) is used as the reference for evaluating the simulations. The simulated medicanes do not coincide in general with the observed cases, so that the evaluation should be done in a statistical sense. The spatial distribution of medicanes is generally well simulated, while the monthly distribution reveals the difficulty of simulating the first medicanes appearing in September after the summer minimum. Large differences are found among models, supporting the use of multi-model ensembles. Interesting trade-offs are found for some models, as better values for intensity are associated to worse frequency values in one model, or relatively good values of frequency and intensity are obtained at the expense of a damped air-sea interaction in a model with spectral nudging. High resolution has a strong and positive impact on the frequency of simulated medicanes, while the effect on its intensity is less clear. Air-sea coupling reduces the medicane frequency, as could be expected due to a negative intensity feedback that is known for tropical cyclones. A preliminary analysis indicates that this feedback could depend on the oceanic mixed layer depth, increasing the interest of applying ocean-atmosphere coupled RCMs
- Published
- 2016
32. The Infrared Method of Determining The Water-Cut of a Nonhomogeneous Water-Gaz-Oil Stream (Russian)
- Author
-
E. V. Zaitcev, B. V. Grigoriev, P. Y. Mikhailov, and S. G. Nikulin
- Published
- 2016
33. Complete genomic sequence of rapidly replicating strain MB-7 of hepatitis a virus and its characterization in comparison with nucleotide sequence of other hepatitis a virus strain
- Author
-
N. I. Kryuk, Sergey V. Netesov, Yu. V. Nemtsov, V. A. Svyatchenko, Vladimir A. Ternovoi, E. V. Chausov, V. V. Yashin, L. G. Nikulin, A. G. Kuslii, N. N. Kiselev, M. U. Muntyanova, and T. Yu. Bondarenko
- Subjects
Genetics ,Untranslated region ,Strain (chemistry) ,Phylogenetic tree ,viruses ,Nucleic acid sequence ,virus diseases ,Biology ,Microbiology ,Genome ,Virology ,Infectious Diseases ,Viral replication ,Phylogenetics ,Molecular Biology ,Gene - Abstract
Complete nucleotide sequence of genomic RNA of hepatitis A virus (HAV) rapidly replicating strain MB-7 was determined. Comparison of nucleotide and deduced amino-acid sequences demonstrated the highest level of identity of MB-7 with strain HAS-15 (above 99%) and high homology with other HAV strains (HM 175/7, CR326, and GBM/HFS) used in production of anti-hepatitis A vaccines. MB-7 was classified as subgenotype IA. Phylogenetic analysis showed that MB-7 is most closely related to the strain HAS-15 and the HAV variants circulating in Russia. Comparative analysis of genomic differences between MB-7 and HAS-15 with other HAV strains revealed among changes characteristic of MB-7 those typical of the described earlier rapidly replicating HAV strains (nt. 149-162 in 5'-untranslated region and changes in the VP3 and 2C genes). These results suggest the functional importance of changes in above-mentioned regions of HAV genome for the increased replication level of MB-7 in vitro.
- Published
- 2010
34. Brownian motion in a solitary potential well in a bounded solid structure
- Author
-
M. V. Sviridov, M. G. Nikulin, and S. A. Guz
- Subjects
Physics ,Phase transition ,Acoustics and Ultrasonics ,Phonon ,Quantum mechanics ,Bounded function ,Spectral density ,White noise ,Statistical physics ,Fluctuation spectrum ,Noise (electronics) ,Brownian motion - Abstract
The motion of a heavy Brownian particle in a low-dimensional bounded solid structure under the effect of a phonon’s excitation fluctuations is considered. Because of the finiteness of the system, the fluctuation spectrum has zero spectral density at zero frequency. The effect of this kind of noise, which is conditionally called “green” noise, is studied both analytically by using the averaging method and numerically on the basis of predictor-corrector algorithms. The effective potential is introduced, and its form is shown to govern the particle dynamics. Considering a Gaussian potential well (a trap) as an example, it is demonstrated that green noise leads to abrupt phase transitions in the system as a result of very small parameter variations (a catastrophe-type effect). The results are compared with the case of white noise in an unbounded structure. From numerical calculations, it follows that the boundedness of the structure, which changes the noise spectrum, favors a considerable increase in the lifetime of the particle in the trap.
- Published
- 2010
35. Formulation and Rheology of Tape Casting Suspensions Based on BaTiO3 Nanopowders
- Author
-
Andrey Ragulya, S. E. Ivanchenko, I. O. Dulina, S. O. Umerova, and A. G. Nikulin
- Subjects
Tape casting ,Materials science ,business.industry ,Hardware_PERFORMANCEANDRELIABILITY ,Dielectric ,chemistry.chemical_compound ,Rheology ,chemistry ,Hardware_GENERAL ,Barium titanate ,Hardware_INTEGRATEDCIRCUITS ,Microelectronics ,Composite material ,Ceramic capacitor ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Reducing the size of microelectronic objects is always an important goal. Reducing the size and increasing of the capacity of multilayer ceramic capacitors can be achieved by reducing the thickness of its dielectric layers.
- Published
- 2015
36. [Untitled]
- Author
-
Yu. P. Matsitskii, S. M. Bednov, A. G. Nikulin, F. S. Zavelevich, and S. M. Khramov
- Subjects
Materials science ,Spectrometer ,business.industry ,Infrared ,Resolution (electron density) ,General Engineering ,Fourier transform spectrometers ,Analytical chemistry ,Limiting ,Condensed Matter Physics ,symbols.namesake ,Optics ,Fourier transform ,Impurity ,Condensed Matter::Superconductivity ,symbols ,Dimethylhydrazine ,business - Abstract
An experimental setup created on the basis of an infrared Fourier spectrometer and intended for an analysis of ultrasmall impurities in liquids and gases is described. Results of experimental studies of the vapor of ultrapure ammonium and nonsymmetric dimethylhydrazine are reported. It is shown that the limiting mole concentration of the detected impurities amounts to about (3–9)·10−4% for different types of gases.
- Published
- 2001
37. Effect of the ionization process on the focusing of a relativistic electron beam by a gas-plasma lens
- Author
-
S. V. Vinogradov, M. G. Nikulin, and S. I. Kudashkin
- Subjects
Physics ,Physics and Astronomy (miscellaneous) ,Physics::Plasma Physics ,Ionization ,Electron beam welding ,Physics::Accelerator Physics ,Relativistic electron beam ,Plasma ,Laser beam quality ,Atomic physics ,Beam parameter product ,Beam (structure) ,Electrostatic lens - Abstract
A numerical simulation is made of the processes occurring in a plasma lens under conditions when the focusing of a relativistic electron beam is strongly affected by the ionization of the residual gas in the lens region by the beam itself. The paraxial, azimuthally symmetric, 1.5-dimensional, electrostatic kinetic model, taking account of plasma production, expansion of the plasma electrons away from the beam region, and contraction of the ions toward the axis of the beam, was used for the calculation. The dynamics of the formation of a focal spot is studied, and the size and position of the spot are determined as functions of time for different values of the gas pressure, initial plasma density, and energy of the beam electrons.
- Published
- 1997
38. Beam-plasma discharge in the propagation of a long-pulse relativistic electron beam in a medium-pressure rarefied gas
- Author
-
M. V. Gladyshev and M. G. Nikulin
- Subjects
Physics ,Physics and Astronomy (miscellaneous) ,Physics::Plasma Physics ,Ionization ,Numerical analysis ,Physics::Accelerator Physics ,Relativistic electron beam ,Electron ,Plasma ,Atomic physics ,Dissociative recombination ,Beam (structure) ,Ion - Abstract
A theoretical model is given, along with a numerical analysis of the evolution of beam-plasma discharge in the propagation of a long-pulse relativistic electron beam in a rarefied gas at medium pressure. It is shown that the self-stabilization of beam-plasma discharge as a result of longitudinal inhomogeneity of the density of the discharge plasma makes it possible for the beam to traverse the beam chamber with relatively low total energy losses, including ionization losses and energy losses in the generation of oscillations. During the dissociative recombination of electrons and ions of the discharge-driven plasma, heat is released and spent in raising the temperature of the gas. The investigated collective-discharge mechanism underlying heating of the gas for a relativistic beam can be more efficient than the classical heating mechanism due to ionization losses of the beam in pair collisions of its electrons with gas particles.
- Published
- 1997
39. The sudden stratospheric warming of the Arctic winter 2009/2010: comparison to other recent warm winters
- Author
-
J. Kuttippurath and G. Nikulin
- Subjects
Arctic dipole anomaly ,Climatology ,Environmental science ,Sudden stratospheric warming ,Atmospheric sciences ,The arctic - Abstract
The Arctic winter 2009/10 was moderately cold in December. A minor warming occurred around mid-December due to a wave 2 amplification split the lower stratospheric vortex into two lobes. The vortices merged again and formed a relatively large vortex in a few days. The temperatures began to rise by mid-January and triggered a major sudden stratospheric warming (SSW) by the reversal of westerlies in late (24–26) January, driven by a planetary wave 1 with a peak amplitude of about 100 m2 s−2 at 60° N/10 hPa. The momentum flux associated with this warming showed the largest value in the recent winters, about 450 m2 s−2 at 60° N/10 hPa. The associated vortex split confined to altitudes below 10 hPa and hence, the major warming (MW) was a vortex displacement event. Large amounts of Eliassen-Palm (EP) and wave 2 EP fluxes (3.9 ×105 kg s−2) are found shortly before the MW event at 100 hPa over 45–75° N, suggesting a tropospheric preconditioning of the MW event. We observe an increase in SSWs in the Arctic in recent years, as there were 6 MWs in 6 out of the 7 winters of 2003/04–2009/10, which confirms the conclusions of previous studies on the SSWs in winters prior to 2003/04. Each MW event was unique as far as its evolution and related polar processes were concerned. As compared to the MWs in the recent Arctic winters, the strongest MW was observed in 2008/09 and was initiated by a wave 2 event. A detailed diagnosis of ozone loss during the past fifteen years shows that the loss is inversely proportional to the intensity and timing of SSWs in each winter, where early MWs lead to minimal loss. The ozone loss shows a good correlation with the zonal mean amplitude of zonal winds in January over 60–90° N, suggesting a proxy for MWs in the Arctic winters.
- Published
- 2012
40. Supplementary material to 'Record-breaking ozone loss in the Arctic winter 2010/2011: comparison with 1996/1997'
- Author
-
J. Kuttippurath, S. Godin-Beekmann, F. Lefèvre, G. Nikulin, M. L. Santee, and L. Froidevaux
- Published
- 2012
41. Experimental research of 'microcable in a microconduct' system stability to effect of freezing water
- Author
-
Vladimir A. Andreev, Sergey A. Gavryushin, Tatiana G. Nikulina, Aleksey G. Nikulin, Ivan N. Alekhin, Denis E. Praporshchikov, and Vladimir A. Burdin
- Subjects
Optical fiber cable ,chemistry.chemical_classification ,Materials science ,chemistry ,law ,System stability ,Tube (fluid conveyance) ,Polymer ,Composite material ,Experimental research ,law.invention - Abstract
Results of experimental researches of "optical microcable in a microduct" system stability to effect of freezing water are presented. It is shown this system is steadier to water freezing in comparison to lighten optical cable in protective polymer tube.
- Published
- 2012
42. [Complete genomic sequence of rapidly replicating strain MB-7 of hepatitis a virus and its characterization in comparison with nucleotide sequences of other hepatitis A virus strains]
- Author
-
T Iu, Bondarenko, V A, Ternovoĭ, V A, Sviatchenko, N N, Kiselev, E V, Chausov, M A, Muntianova, Iu V, Nemtsov, V V, Iashin, N I, Kriuk, A G, Kusliĭ, L G, Nikulin, and S V, Netesov
- Subjects
Viral Proteins ,Base Sequence ,Sequence Analysis, RNA ,Sequence Homology, Nucleic Acid ,Molecular Sequence Data ,Humans ,RNA, Viral ,Hepatitis A ,Virus Replication ,Hepatitis A Virus, Human ,Phylogeny - Abstract
Complete nucleotide sequence of genomic RNA of hepatitis A virus (HAV) rapidly replicating strain MB-7 was determined. Comparison of nucleotide and deduced amino-acid sequences demonstrated the highest level of identity of MB-7 with strain HAS-15 (above 99%) and high homology with other HAV strains (HM 175/7, CR326, and GBM/HFS) used in production of anti-hepatitis A vaccines. MB-7 was classified as subgenotype IA. Phylogenetic analysis showed that MB-7 is most closely related to the strain HAS-15 and the HAV variants circulating in Russia. Comparative analysis of genomic differences between MB-7 and HAS-15 with other HAV strains revealed among changes characteristic of MB-7 those typical of the described earlier rapidly replicating HAV strains (nt. 149-162 in 5'-untranslated region and changes in the VP3 and 2C genes). These results suggest the functional importance of changes in above-mentioned regions of HAV genome for the increased replication level of MB-7 in vitro.
- Published
- 2010
43. The exceptional earthquakes in Kaliningrad district, Russia on September 21, 2004
- Author
-
Wojciech Debski, A. G. Aronov, Gottfried Grünthal, Päivi Mäntyniemi, Paweł Wiejacz, B. Domanski, B. A. Assinovskaya, T. I. Aronova, V. G. Nikulin, V. Puura, Saulius Šliaupa, Eystein S. Husebye, A. Pacesa, B. Guterch, and S. Gregersen
- Subjects
geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Physics and Astronomy (miscellaneous) ,Astronomy and Astrophysics ,550 - Earth sciences ,Fault (geology) ,010502 geochemistry & geophysics ,Strike-slip tectonics ,01 natural sciences ,Geological structure ,Geophysics ,Space and Planetary Science ,Peninsula ,Intraplate earthquake ,East European Craton ,Seismology ,Geology ,0105 earth and related environmental sciences - Abstract
The earthquakes of magnitudes M w 5.0 and 5.2 in the Kaliningrad enclave of Russia on September 21, 2004 were unexpected in a low-seismicity area. The earthquakes caused moderate damage in the Kaliningrad enclave, and smaller damage in northern Poland and in southern and western Lithuania. The largest earthquake was the strongest ever recorded instrumentally in the region, and it was felt at distances up to 800 km. In directions towards the west and south the perceptibility area is abruptly cut off by the Tornquist-Teisseyre Zone, the south-west margin of the East European Craton. The earthquakes are instrumentally located at depths 16–20 km under the central-northern part of the Sambia Peninsula in the Kaliningrad enclave. For these events it is noted that the macroseismic calculations of 10–19 km depths are in reasonable agreement. The source mechanism of the largest earthquake was determined to be a right lateral strike slip on a WNW-ESE near-vertical fault of orientation almost parallel to the Tornquist-Teisseyre Zone and to the north coast of the Sambia Peninsula. Based on available stress information it is interpreted that the underlying cause of the earthquakes is the absolute plate motion. Historical information is scanty. It is searched in an attempt to evaluate past seismic activity in the region, and to evaluate vulnerable weakness zones in the geological structures.
- Published
- 2007
44. Brownian motion in tilted periodic potential driven by green impulse noise
- Author
-
S. A. Guz, Michael G. Nikulin, and M. V. Sviridov
- Subjects
Gradient noise ,symbols.namesake ,Control theory ,Colors of noise ,Gaussian noise ,Noise spectral density ,Time derivative ,Mathematical analysis ,symbols ,Impulse (physics) ,Impulse noise ,Brownian motion ,Mathematics - Abstract
We study a Brownian overdamped motion driven by the sequence of non-Gaussian correlated random impulses. A main characteristic of this external noise is that a following impulse has strictly opposed sign relative to the previous one. It is generated by a time derivative of stationary random jump function that may be equal or similar to a random telegraphic signal. Therefore, the noise is "green" by definition [Phys. Lett. A240 (1998) 43]. In order to find the mean drift velocity of a Brownian particle we employ two approaches: a Krylov-Bogolubov averaging method and a numerical simulation. The first method is used for the case of the jump function to be the random telegraphic signal. Then the probability dis-tribution density that describes statistics of time interval between the delta-function impulses of external noise is an ex-ponential function. The numerical calculation is performed by means of using the narrow rectangular impulse instead of the delta-function. We consider two models of such noise. In the first case the distribution density of time interval be-tween the rectangular impulses is again described by the exponential function. In other case the interval is uniformly distributed. We show that a locking effect (or a synchronization) exists even if a mean frequency of impulses is small. This effect exists with a high accuracy even if noise is strong. According to the theory an effective locking band is equal to the cosine of the amplitude of the original jump function. In particular, if the amplitude is π, the band is zero, how-ever, if it is equal to π, the band is unity as well as in the ideal case of zero noise. It is interesting that this property holds true even if the averaging method becomes inapplicable. We show also that the theory good coincide with the numerical simulation.
- Published
- 2006
45. State-of-the-art of historical earthquake research in Fennoscandia and the Baltic Republics
- Author
-
Päivi Mäntyniemi, V. G. Nikulin, T. R. M. Kebeasy, A. A. Nikonov, Eystein S. Husebye, and A. Pacesa
- Subjects
Seismometer ,010504 meteorology & atmospheric sciences ,Project commissioning ,business.industry ,media_common.quotation_subject ,lcsh:QC801-809 ,Magnitude (mathematics) ,historical earthquakes ,Nuclear power ,lcsh:QC851-999 ,010502 geochemistry & geophysics ,01 natural sciences ,lcsh:Geophysics. Cosmic physics ,Geophysics ,Work (electrical) ,State (polity) ,Period (geology) ,lcsh:Meteorology. Climatology ,Physical geography ,Seismic risk ,business ,Geology ,Seismology ,0105 earth and related environmental sciences ,media_common - Abstract
We review historical earthquake research in Northern Europe. 'Historical' is defined as being identical with seismic events occurring in the pre-instrumental and early instrumental periods between 1073 and the mid-1960s. The first seismographs in this region were installed in Uppsala, Sweden and Bergen, Norway in 1904-1905, but these mechanical pendulum instruments were broad band and amplification factors were modest at around 500. Until the 1960s few modern short period electromagnetic seismographs were deployed. Scientific earthquake studies in this region began during the first decades of the 1800s, while the systematic use of macroseismic questionnaires commenced at the end of that century. Basic research efforts have vigorously been pursued from the 1970s onwards because of the mandatory seismic risk studies for commissioning nuclear power plants in Sweden, Finland, NW Russia, Kola and installations of huge oil platforms in the North Sea. The most comprehensive earthquake database currently available for Northern Europe is the FENCAT catalogue covering about six centuries and representing the accumulation of work conducted by many scientists during the last 200 years. This catalogue is given in parametric form, while original macroseismic observations and intensity maps for the largest earthquakes can be found in various national publications, often in local languages. No database giving intensity data points exists in computerized form for the region. The FENCAT catalogue still contains some spurious events of various kinds but more serious are some recent claims that some of the presumed largest historical earthquakes have been assigned too large magnitude values, which would have implications for earthquake hazard levels implemented in national building codes. We discuss future cooperative measures such as establishing macroseismic data archives as a means for promoting further research on historical earthquakes in Northern Europe.
- Published
- 2004
46. [Use of Bifidobacterium-containing therapeutic dietetic food products in the prevention of dysbacteriosis]
- Author
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R M, Il'ina, A V, Molokeev, L G, Nikulin, and N V, Molokeeva
- Subjects
Adult ,Foods, Specialized ,Male ,Time Factors ,Adolescent ,Adolescent Nutritional Physiological Phenomena ,Age Factors ,Infant, Newborn ,Infant ,Diet ,Intestines ,Lactobacillus acidophilus ,Sex Factors ,Child, Preschool ,Humans ,Female ,Infant Food ,Bifidobacterium ,Child Nutritional Physiological Phenomena ,Infant Nutritional Physiological Phenomena - Published
- 2001
47. [Genetic and biological characteristics of noninbred mice from the ICR colony]
- Author
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T L, Karikh, A V, Molokeev, and L G, Nikulin
- Subjects
Male ,Mice ,Mice, Inbred ICR ,Fertility ,Polymorphism, Genetic ,Genotype ,Longevity ,Animals ,Female ,Fetal Death - Abstract
Noninbred mice of the ICR colony were studied by a set of characters making it possible to estimate the range of genetic polymorphism in the given population. Genotypes of mice for loci A-, B-, D-, S-, PP, Se Se, and cc were determined. Noninbred mice were polymorphic for loci A, B, D, and S. Frequencies of recessive alleles of loci A, B, and D was calculated. Noninbred mice have a high fecundity and a low level of embryonic mortality, which indicate population heterogeneity. The age of the mother was shown to have no effect on the ovulation norm. The population standard of the colony for age-dependent change in the body weight and size was established. Age-dependent survival in females and males was shown to be associated.
- Published
- 1999
48. Development of advanced technologies for future cryogenic thrust chamber applications
- Author
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W. Zinner, D. Haeseler, C. Maeding, V. Rubinskij, V. Gorochov, S. Hrisanfov, and G. Nikulin
- Subjects
Engineering ,business.industry ,Thrust chamber ,Mechanical engineering ,Aerospace engineering ,business - Published
- 1997
49. Advanced rocket engine nozzles
- Author
-
N. Ponomarev, G. Nikulin, and G. Dumnov
- Subjects
Materials science ,business.industry ,Liquid-propellant rocket ,Rocket engine nozzle ,Nozzle ,Rocket engine ,Aerospace engineering ,business - Published
- 1996
50. [The adaptive-compensatory reactions of the pulmonary microcirculatory bed in experimental pneumonia]
- Author
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A M, Kulik, S O, Aleĭnikov, V G, Nikulin, E I, Iakovleva, and L B, Snopova
- Subjects
Male ,Time Factors ,Turpentine ,Microcirculation ,Acute Disease ,Cats ,Animals ,Pneumonia ,Adaptation, Physiological ,Lung - Abstract
Pulmonary microcirculation was studied in anesthetized interbred male cats with acute pneumonia in acute experiments by the method of intravital microscopy. Due to the reticular structure of the lung microcirculatory channel and the change of the direction of the blood flow in microvessels stretching to the focus of inflammation, collateral circulation developed rapidly and facilitated redistribution of the blood flow in the pulmonary lobe involved in the inflammation.
- Published
- 1990
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