Long-period Changes Research Articles

The Algorithm of the Two Neutron Monitors for the Analysis of the Rigidity Spectrum Variations of Galactic Cosmic Ray Intensity Flux in Solar Cycle 24

The method of the two neutron monitors was used to analyze the parameters of the rigidity spectrum variations (RSV) of galactic cosmic ray intensity (GCR) flux in solar cycle 24 based on the data from the global network of neutron monitors. This method is an alternative to the least squares method when there are few monitors working stably in a given period, and their use in the least squares method is impossible. Analyses of the changes in exponent γ in the RSV of GCR flux from 2009 to 2019 were studied. The soft RSV (γ = 1.2–1.3) of the GCR flux around the maximum epoch and the hard RSV (γ = 0.6–0.9) around the minimum epoch of solar activity (SA) is the general feature of GCR modulation in the GeV energy scale (5, 50), to which neutron monitors were found to correspond. Therefore, various values of the RSV γ in the considered period show that during the decrease and increase period of SA, the essential changes in the large-scale structure of the heliospheric magnetic field (HMF) fluctuations/turbulence take place. The exponent γ of the RSV of the GCR flux can be considered a significant parameter to investigate the long-period changes in the GCR flux.

Long-Period Changes in the Frequency of Cyclones in the Northern Hemisphere Temperate Latitudes

Long-Period Changes in the Frequency of Cyclones in the Northern Hemisphere Temperate Latitudes

Change detection and monitoring of active Martian surface phenomena with the Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace Gas Orbiter (TGO)

Mars is host to a variety of active surface processes that relate to changes in seasonal ice/frost, slope activity, wind and processes potentially relating to liquid water. Regular monitoring and change detection of these phenomena is crucial to not only provide us insights into present day Martian surface conditions, but also its past geologic and climatic scenarios. Visual comparisons of high-resolution remote sensing images of the surface from the Mars Reconnaissance Orbiter (MRO) have allowed detailed tracking and monitoring of these changes over time. The CaSSIS instrument onboard the ExoMars Trace Gas orbiter also provides a unique pathway to track areally-large surface changes in colour, that permits us to better constrain origin and evolution of various surface features. Since TGO operates in a non-sun-synchronous orbit, previously adopted qualitative methods like visual image comparisons for MRO cannot be adopted for CaSSIS-based change detection. Consequently, this study lists and describes in detail, the techniques that need to be adopted to conduct such change detection campaigns with CaSSIS, for the variety of active processes currently identified on Mars. This work also proposes and describes two additional semi-quantitative techniques for CaSSIS-based change detection, that may be used in concert with existing visual comparison methods to enable reliable change identification and tracking. It is observed that these supplementary methods work well in characterizing a variety of surface changes related to ice/frost and slope processes, and can provide reasonable spectral constraints to better understand their origin. These methods are not effective in providing quantitative constraints for purely physical changes. Instead, for long-period changes like aeolian bedform movement, digital image correlation techniques on ortho-rectified images, are recommended; while for short period changes like real-time dust devil activity, measurements based on CaSSIS stereo pairs of the region can be used to provide quantitative estimates of change.

АНАЭРОКОНТУР ЧЕРНОГО МОРЯ

The work is devoted to the issue of the allocation of a new contour biotope in the Black Sea. Currently, in hydrobiology, it is customary to distinguish the following contour biotopes or contact zones of the sea: aerocontour, psammocontour, lithocontour, pelocontour, potamocontour (Zaitsev, 2012, 2015), which describe the ecological structure of any reservoir except for the Black Sea. This is due to the fact that most of the deep-water area of this water basin does not have a peloconture with higher forms of life due to hydrogen sulfide in its depths. This biotope exists is only in coastal shelf areas up to depths of 150–200m, where there is still oxygen. Until the end of the last century, it was believed that the Black Sea had only oxygen and hydrogen sulfide zones, with a mixing layer (or C-layer) between them. However, at the beginning of this century, a revolutionary discovery was made in hydrochemistry (Konovalov, Murray, 2001; Konovalov et al., 2005): it turned out that the C-layer does not exist and that the oxygen and hydrogen sulfide layers of water are separated by a special water mass where there is neither oxygen nor hydrogen sulfide. It turned out that this water mass (called the Suboxic layer) has a thickness of about 30-50 m, characteristic physicochemical properties and a certain history of origin (Konovalov et al., 2005). Like any water mass in the sea, it is a biotope that in hydrobiology does not yet have a name, is poorly described and its role in the ecosystem is insufficiently studied. However, there is already evidence that it plays an extremely important role in the ecosystem of the Black Sea because clusters of specific hydrobionts form on its borders and intensive chemosynthesis occurs in it, comparable in production with the photic zone (Polikarpov et al., 1990). This biotope is an obvious contour biotope, the opposite of the aeroconture, which is in contact with the oxygen environment. It is located on the border with anoxic layer and therefore the author called it the "anaerocontour" of the Black Sea. Based on the generalization of existing data and the results of his own research, the author of this work for the first time provides a generalized description of the structural and functional characteristics of this contour biotope and describes its role in the functioning of the ecosystem of the Black Sea. The results of this work are of fundamental interest for understanding biological processes in extreme conditions and their impact on long-period changes in the ecosystem of the Black Sea.

Long-Periodic Analysis of Boresight Misalignment of Ziyuan3-01 Three-Line Camera

The Ziyuan3-01 (ZY3-01) satellite is China’s first civilian stereo surveying and mapping satellite to meet the 1:50,000 scale mapping requirements, and has been operated in orbit for 10 years. The boresight misalignment of the three-line camera (TLC) is an essential factor affecting the geolocation accuracy, which is a principal concern for stereo mapping satellites. However, the relative relationships of TLC are often regarded as fixed for the same ground scene in most traditional geometric calibrations, without considering the on-orbit long-periodic changes. In this paper, we propose a long-periodic method to analyze and estimate the boresight misalignments between three cameras, with the attitude estimation of a nadir (NAD) camera as the benchmark. Offsets and drifts of the three cameras were calculated and calibrated with different compensation models using scale invariant feature transform (SIFT) points as the ground control. Ten simultaneous NAD–Forward (FWD)–Backward (BWD) imagery of the ZY3-01 satellite acquired from 2012 to 2020 were selected to verify the long-periodic changes in TLC boresight misalignments. The results indicate that the boresight alignment angles of ZY3-01 TLC are dynamic during the long-periodic flight, but the structure of TLC is stable for the misalignments of both FWD and BWD within only 7 arc seconds, which can provide a positive reference for subsequent satellite design and long-periodic on-orbit geometric calibration.

ИЗМЕНЕНИЯ ОТНОСИТЕЛЬНОГО УРОВНЯ МОРЯ - ПОВЕРХНОСТНОЕ ВЫРАЖЕНИЕ ГЛУБИННЫХ ПРОЦЕССОВ

The article presents an overview of current ideas about the possible causes and physical mechanisms of relative sea-level changes. The choice of the predominant factor can be demonstrated by the study of stratigraphic sequences formed at the oceanic basin margins or in the epeiric seas of cratonic interior areas. Such studies lead to the conclusion that high frequency fluctuations with a period of less than 1 Myr are caused primarily by the glacial episodes on the land. Fluctuations with a longer period of 1-3 Myr are controlled by intraplate tectonic processes, among which the prograde metamorphism at the crust-mantle boundary is the most important. Lateral stress of lithosphere with laterally variable thickness and the dynamic topography are also possible. Tectonic processes affecting the volume of ocean basins, such as accelerating or decelerating spreading, subduction appear to be in causal relationship with the long-period sea level changes of 10 to 100 Myr and over.

A thermally-electrically double-responsive polycaprolactone – thermoplastic polyurethane/multi-walled carbon nanotube fiber assisted with highly effective shape memory and strain sensing performance

A kind of thermally-electrically responsive shape memory fibers made of polycaprolactone (PCL) and thermoplastic polyurethane (TPU) with electric heating and strain sensing properties was prepared by wet-spinning and dip-coating of multiwalled carbon nanotube (MWCNT) on the fiber surface. Aggregate structure investigation on the PCL-TPU fibers and those coated with MWCNT (PCL-TPU/MWCNT fibers) showed that no obvious change of long period, lamellar thickness or orientation after the fibers were recovered from the deformed states with the strain ranging from 100% to 400%. The melting and crystallization of PCL are the switches of shape memory function. After 9 dip-coating cycles of MWCNT, the content of MWCNT is 1.12 wt%, the steady-state maximum temperature (Tmax) of the as spun PCL-TPU/9WMCNT fiber and the one stretched to a strain of 50% could reach 59.7 °C and 54.4 °C, which were on the melting range of PCL. As thus, the shape memory effects of the PCL-TPU/9MWCNT fiber with a strain of less than 50% could be realized in form of both thermal and electrical stimuli. Meanwhile, the PCL-TPU/9WMCNT fiber showed highly gauge factor (21.11), fast response speed (187 ms), and excellent cycle stability (2000 cycles) at a strain of 20%. A linear relation between strain and resistance change was found for this type of MWCNT coated PCL-TPU fiber on all the three different strain regions from 0% to 300%, which was an important criterion for their application on strain sensors. As a whole, the PCL-TPU/MWCNT fiber prepared in this work could serve as an excellent sensing unit for wearable devices.

Long-term changes of the thermal characteristics in the Japan Sea surface water and peter the great bay and their relationship with large-scale climatic processes

Analysis of the long-period changes of the surface thermal characteristics in the Japan Sea, including the ice cover of Peter the Great Bay, was carried on the basis of the regional databases formed from open sources. The relationship of the observed changes with large-scale processes characterized by well-known climatic indices was investigated. It was revealed that surface temperature changes in the Japan Sea, its Northern part and in Peter the Great Bay in winter and summer occur synchronously. In the new century (2001–2017), the growth rate of the sea surface temperature slowed down in comparison with the last 25 years of the 20th century. The most influential in these areas were the large-scale processes, which are characterized by the index of the Siberian anticyclone and the West Pacific index. We also analyzed the sustainability of the statistical relationships between regional thermal characteristics and large-scale climate indices. Special attention was paid to the change in the character of the relationships at different time periods. The pronounced rearrangements of the linkages accompanied by a change in the sign of the correlation coefficients corresponded to the well known climatic regime shifts in most of the cases under study. The most notable restructuring occurred in 1988/89.

Long-period changes of the air temperature in Tatarstan and their forecast till the end of the 21st century

Long-term changes in air temperature on the territory of the Republic of Tatarstan in the 20th–21st centuries are considered. The periods of unambiguous changes in the surface air temperature are determined. It is established that the average winter temperature from the 1970s to 2017, increased in the Kazan region by more than 3 °C and the average summer temperature increased by about 2 °C over the same period. The contribution of global scale processes to the variability of the temperature of the Kazan region is shown: it was 37 % in winter, 23 % in summer. The correlation analysis of the anomalies of average annual air temperature in Kazan and the series of air temperature anomalies in each node over the continents, as well as the ocean surface temperature in each coordinate node on Earth for 1880 –2017, was performed. Long-distance communications were detected in the temperature field between Kazan and remote regions of the Earth. It is noted that long-period climate fluctuations in Kazan occur synchronously with fluctuations in the high latitudes of Asia and North America, with fluctuations in ocean surface temperature in the Arctic ocean, with fluctuations in air temperature in the Far East, and with fluctuations in ocean surface temperature in the Southern hemisphere in the Indian and Pacific oceans, as well as air temperature in southern Australia. It is suggested that there is a global mechanism that regulates long-term climate fluctuations throughout the Earth in the considered interval of 200 years of observations. According to the CMIP5 project, climatic scenarios were built for Kazan until the end of the 21st century.

On optimal trajectory for the multi-period evolution of FTTx networks

We propose a business/cost model for long-period changes of customer demands in FTTx networks. We show how to exploit this model in the formulation of a MIP optimization problem that, for a given sequence of customer demand vectors provides (when solved to the optimality) the absolute benchmark. The model is relatively complicated and cannot be directly applied to the optimization of real-world networks without a number of algorithmic tricks that are discussed in this paper. The presented approach has been implemented and tested against an example network instance. Test results are given and discussed in the paper.

An Opportunity for the Working Class with Increased Markups

This article presents an analysis based on a comparison of stationary states. With technology and relative markups among industries taken as exogenous, the long-period trade-off between wages and rates of profits is determined. A long-period change in relative markups among industries can create a switch point exhibiting capital-reversing. Around such a switch point, a higher wage is associated with firms wanting to employ more labor for a given net output – a favorable occurrence for organized labor.

Long-Term Variability of UV Irradiance in the Moscow Region according to Measurement and Modeling Data

We have found distinct long-period changes in erythemal UV radiation (Qer) characterized by a pronounced decrease at the end of the 1970s and a statistically significant positive trend of more than 5%/10 years since 1979 over the territory of the Moscow region according to the measurements and reconstruction model. The positive Qer trend is shown to be associated mainly with a decrease in the effective cloud amount and total ozone content (TOC). Due to these variations, UV resources have significantly changed in spring for the population with the most vulnerable skin type I, which means a transition from the UV optimum to UV moderate excess conditions. The simulation experiments using the INM-RSHU chemistry climate model (CCM) for several scenarios with and without anthropogenic factors have revealed that the variations in the anthropogenic emissions of halogens have the most significant impact on the variability of TOC and Qer. Among natural factors, noticeable effects are observed due to volcanic aerosol. The calculations of the cloud transmittance of Qer are generally consistent with the measurements; however, they do not reproduce the observed value of the positive trend.

Tensile Deformation of Bulk Polyamide 6 in the Preyield Strain Range. Micro–Macro Strain Relationships via in Situ SAXS and WAXS

The macroscopic tensile deformation behavior of bulk PA6 was investigated in the elastic strain range. Samples having predominant α and β crystal structures were prepared thanks to appropriate crystallization procedures. Both materials were studied above and below the glass transition temperature of the amorphous phase. In parallel, the microscopic deformation behavior of these samples was followed up by combined in situ wide-angle and small-angle X-ray scattering. The change of SAXS long period over the whole azimuthal distribution was used to assess the local deformation at the scale of the lamella stacks in all directions. The WAXS patterns were used to assess the local crystal strains. Local stresses were further computed thanks to the elastic constant borrowed from the literature. The whole set of data allowed to establish micro–macro strain correlations and to determine the local elastic properties in the crystalline and amorphous phases. The effective tensile modulus of the amorphous phase of PA6 w...

Periodicities of the RV Tauri-type pulsating star DF Cygni: A combination ofKeplerdata with ground-based observations

The RV Tauri stars constitute a small group of classical pulsating stars with some dozen known members in the Milky Way. The light variation is caused predominantly by pulsations, but these alone do not explain the full complexity of the light curves. High quality photometry of RV Tau-type stars is very rare. DF Cygni is the only member of this class of stars in the original Kepler field, hence allowing the most accurate photometric investigation of an RV Tauri star to date. The main goal is to analyse the periodicities of the RV Tauri-type star DF Cygni by combining four years of high-quality Kepler photometry with almost half a century of visual data collected by the American Association of Variable Star Observers. Kepler quarters of data have been stitched together to minimize the systematic effects of the space data. The mean levels have been matched with the AAVSO visual data. Both datasets have been submitted to Fourier and wavelet analyses, while the stability of the main pulsations has been studied with the O-C method and the analysis of the time-dependent amplitudes. DF Cygni shows a very rich behaviour on all time-scales. The slow variation has a period of 779.606 d and it has been remarkably coherent during the whole time-span of the combined data. On top of the long-term cycles the pulsations appear with a period of 24.925 d. Both types of light variation significantly fluctuate in time, with a constantly changing interplay of amplitude and phase modulations. The long-period change (i.e. the RVb signature) somewhat resembles the Long Secondary Period (LSP) phenomenon of the pulsating red giants, whereas the short-period pulsations are very similar to those of the Cepheid variables. Comparing the pulsation patterns with the latest models of Type-II Cepheids, we found evidence of strong non-linear effects directly observable in the Kepler light curve.

A new viscoelastic method of calculation of low-temperature thermal stresses in asphalt layers of pavements

The paper presents a new method of calculation of thermal stresses in asphalt layers of pavements induced by cooling or heating. The method, developed by the author, is based on the analytical solution for the linear viscoelastic Burgers model extended numerically for the case of asphalt layers whose rheological parameters are strongly dependent on temperature. The coefficient of thermal expansion and Poisson’s ratio may optionally be taken either as constant or varying with temperature. Two equivalent numerical methods have been developed, named as ‘the incremental method’ and ‘the stress increase and relaxation method’. The computer program was developed for calculation of thermal stresses in several different cases of temperature impact, included constant rate cooling and heating, change of temperature and relaxation and a cycle of first cooling, relaxation and second cooling. What the most important practically, the solution for any change of temperature, modelling real winter changes in long period of time, was also developed. Several examples of calculations are presented. The results obtained with use of this method are promising and appear to be acceptable. The advantages of the new method in comparison with existing methods are that it takes fully into account the viscoelastic properties of a layer and the method is correct if the material does not meet the time–temperature superposition principle.

Reversible shape‐memory properties of surface functionalizable, crystallizable crosslinked terpolymers

There is a high demand for polymer actuators comprising reactive groups at their surface in biotechnological or bioanalytical devices especially in microfluidics. In this work, we explored whether a thermoplastic poly[ethylene‐co‐(ethyl acylate)‐co‐(maleic anhydride)] (PEEAMA) terpolymer can be converted to a multifunctional shape‐memory actuator by introducing covalent netpoints. In crosslinked PEEAMA (cPEEAMA) crystalline polyethylene (PE) domains with melting temperatures below 70°C should serve as actuation domains, responsible for the reversible shape change during cyclic heating and cooling, while higher melting PE crystals act as skeleton forming domains; finally maleic anhydride (MAH) groups enable surface modification of the polymeric substrate. cPEEAMAs with a fixed composition and various crosslink densities were prepared by thermally crosslinking of PEEAMA using different dicumyl peroxide (DCP) concentrations in the starting reaction mixture. A broad melting transition in the range of 50 to 90°C with a melting temperature interval of ∆Tm = 40°C, related to the crystalline PE domains, was observed for all polymer networks in differential scanning calorimetric experiments. Cyclic, thermomechanical uniaxial tensile tests revealed high reversible strains up to 17 ± 2%. A reversible change in long period during repetitive heating and cooling was observed in in situ small angle X‐ray scattering experiments. Finally, a successful functionalization of the MAH groups at the cPEEAMA surface by reaction with ethylene diamine was confirmed by infrared spectroscopy analysis. The presented amino functionalized cPEEAMA substrates could be a candidate material for the preparation of adaptive microfluidic devices. Copyright © 2015 John Wiley & Sons, Ltd.

Investigation on the recovery performance of olefin block copolymer/hexadecane form stable phase change materials with shape memory properties

In this work, recovery performance of a novel sort of form stable phase change materials (FSPCMs) with simultaneously shape memory properties was investigated systematically. The FSPCMs comprising hexadecane as latent heat storage material and olefin block copolymer (OBC) as supporting material were prepared by simple swelling preparation method. This kind of difunctional materials exhibits fantastic shape memory properties with mass fraction of hexadecane reaching 70wt%, which indicates excellent energy storage ability as well. It is found that the recovery performance under 50% strain is obviously better than that under higher strains for all the specimens investigated, while surprisingly, the composite with 70wt% hexadecane exhibits better recovery performance than pure OBC as well as the composite with 30wt% hexadecane at strains of 100 and 200%. The structural change brought by incorporation of hexadecane was explored with in situ two-dimensional X-ray scattering measurements. According to experiment results, we find that the recovery performance is closely correlated to change of long period, indicating the irreversible deformation of the difunctional materials may originate from lamellar fragmentation of OBC, while addition of massive hexadecane is beneficial to restrain lamellar fragmentation and thus improves the recovery performance. We believe this exploration may shed light on comprehending the relationship between structural change and shape memory performance, thus contributing to adjusting the properties of the difunctional materials and expanding their potential applications.

Structure evolution during uniaxial tensile deformation of high density polyethylene before and after irradiation by 1 MeV electrons

AbstractThe structural evolution of high density polyethylene (HDPE) during uniaxial tensile deformation, before and after irradiation by 1 MeV electrons, is in situ studied by synchrotron small angle X‐ray scattering (SAXS) and wide angle X‐ray diffraction (WAXD). Both the pristine and the irradiated HDPE exhibit three regions of deformation behavior. It is shown that the deformation in the first region is in accord with the change in long period of the lamellar structure. In the following two regions, both the strain‐induced melting and strain‐induced crystallization could occur. The tensile stress decreases with strain in the second region due to the dominant melting effect. In the third region, the synergistic effect of the melting and crystallization results in stress leveling off first, and then the tensile stress increases again because the crystallization effect becomes dominant at higher strains. For the irradiated HDPE, the irradiation‐induced crosslinking network slows down the deformation process. Compared to the pristine one, all the tensile stress is rather higher at a given strain for the irradiated HDPE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40269.

Paschim Himalaya ke mausam tatha him par jalvayu parivartan ka pratighat

The complex topographical features of the Indian sub continent such as the high Himalayan ranges have started showing the affects of global climate change. Himalaya modulates weather over the entire northern belt of the Indian sub-continent. It also influences the Western Disturbances (WDs) during winter over the region. Some recent trends in the parameters of weather and climate over the Western Himalayan region have been studied and explanations have been given in context of climate change over these regions. The studies show how the climate changes in long term period with reference to the total precipitation over the station locations of these regions. Data analysis of Western Himalaya shows significant variations in temperature and total precipitation trends in the past few decades. The results show negative Correlation Coefficients (CCs) between the mean maximum and mean minimum temperature with the fresh snowfall the different station locations over Western Himalaya. The possible effects of the climate change on the number of snowfall days over the Western Himalayan region have also been analyzed. There is clear sign of shrinking winter over the Western Himalaya. Necessary efforts have been directed to understand the science of climate change more in regional scale over this complex orographic region.

Climatic variations of general atmospheric circulation,precipitation and river flow of the territory of Kazakhstan

Methods of calculating the basic hydrological characteristics of a water resource assessment, as well as the planning and management of their long-term use are based upon the concept of stationarity of long-term flow fluctuations. However, data of researches by hydrologists and climatologists clearly indicate that there are long-period changes in the characteristics of precipitation and river flow. This article discusses the variations of annual precipitation and river flow in the Ishim River Basin in Kazakhstan, based on the W, C and E classification developed by G.Y. Vangengeim who analyzed the long-term variability of anomalies by the number of days with some form of atmospheric circulation. From this study, the largest anomaly of the macro-circulation processes was revealed, and a comparative analysis of the number of days with various forms of atmospheric circulation and precipitation anomalies was made. It was demonstrated that the nature of atmospheric circulation depends on the distribution of precipitation; however, precipitation is also highly dependent on local physiographic conditions. The analysis of anomalous precipitation during the maximum number of days of positive anomalies with various forms of atmospheric circulation was also carried out. This study presents some results from the preliminary analysis of annual river flow linked with forms of atmospheric circulation.