Ferrimagnetism of dilute Ising antiferromagnets

It is shown that nearest-neighbor antiferromagnetic interactions of identical Ising spins on imbalanced bipartite lattice and imbalanced bipartite hierarchical fractal result in ferrimagnetic order instead of antiferromagnetic one. On some crystal lattices dilute Ising antiferromagnets may also become ferrimagnets due to the imbalanced nature of the magnetic percolation cluster when it coexists with the percolation cluster of vacancies. As evidenced by the existing experiments on $Fe_pZn_{1-p}F_2$, such ferrimagnetism is inherent property of bcc lattice so thermodynamics of these compounds at low $p$ can be similar to that of antiferromagnet on imbalanced hierarchical fractal.Comment: 6 pages, 4 figure

Pretransitional phenomena in dilute crystals with first-order phase transition

Pretransitional phenomena at first-order phase transition in crystals diluted by 'neutral' impurities (analogue of nonmagnetic atoms in dilute magnets) are considered. It is shown that field dependence of order parameter becomes nonanalytical in the stability region of the ordered phase, while smeared jumps of thermodynamic parameters and anomalous (non-exponential) relaxation appear near transition temperature of pure crystal.Comment: 4 page

Spectral and mechanical properties of the materials structured with carbon nanotubes

Carbon nanotubes are considered as the good candidate to modify the surface properties of the organic and inorganic structures. Both the spectral and mechanical properties as well as quantum chemical simulation are discussed to explain the increase in transmission and hardness of the nanostructured polyvinyl alcohol films, magnesium fluoride, etc. The basic features of carbon nanotubes are regarded to their small refractive index, strong hardness of C⎯C bonds as well as complicated and unique mechanisms of charge carrier moving. The structures of the composite films and their mechanical properties are modeled too. The peculiarities of new nanostructured materials and their possible optoelectronics and display applications will be under consideration. The results have been supported by RFBR grant #10-03-00916 and RAS Presidium Program # 21

Assessment of the body composition of football players based on anthropometry and bioimpedansometry data and a comparison of two registration methods

Objective: comparative analysis of body composition indicators obtained by two methods of data registration — anthropometry and bioimpedance measurement, and analysis of the distribution of subcutaneous fat on the body of football players in accordance with the playing role.Materials and methods: аnthropometric measurements and bioimpedance studies of body composition were carried out in 24 football players of the Moscow football club of the second division professional football league. The average age of the athletes was 24.16 ± 0.87 years.Results: the survey involved 24 football players of the Moscow football club of the professional football league of the second division. The average age of the players was 24.16 ± 0.87 years. When determining the composition of the body using two methods, it was found that the calculation method and the bioimpedance method give different results. On average, the calculation method shows higher indicators of body fat mass (%FBM = 18.9 ± 1.04) than the bioimpedance method (%FBM = 14.7 ± 0.76), the differences are significant (p < 0.05). Moreover, differences in muscle mass are insignificant — in terms of BIA %SMM = 47.06 ± 0.59, according to the calculation method %SMM = 47.0 ± 0.63 (the differences are unreliable, p > 0.05). There were no differences in the component composition of the body of football players depending on the game role. The topography of subcutaneous fat on the body of athletes-football players has certain patterns, but does not depend on the playing role of athletes.Conclusion: the analysis revealed differences in the body composition data of football players obtained using two registration methods. The data of the study can serve as model criteria for body composition and the distribution of subcutaneous fat on the body of athletes for selection in football activities and for comparative characterization and discussion of the results of similar studies

Scaling and finte-size-scaling in the two dimensional random-coupling Ising ferromagnet

It is shown by Monte Carlo method that the finite size scaling (FSS) holds in the two dimensional random-coupled Ising ferromagnet. It is also demonstrated that the form of universal FSS function constructed via novel FSS scheme depends on the strength of the random coupling for strongly disordered cases. Monte Carlo measurements of thermodynamic (infinite volume limit) data of the correlation length ($\xi$) up to $\xi \simeq 200$ along with measurements of the fourth order cumulant ratio (Binder's ratio) at criticality are reported and analyzed in view of two competing scenarios. It is demonstrated that the data are almost exclusively consistent with the scenario of weak universality.Comment: 9 pages, 4figuer

The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described

Мониторинг ледника Колка в 2014–2017 гг. методом наземной стереофотосъёмки

The Kolka Glacier, which rushed down the Genaldon valley on September 20, 2002 (North Ossetia), is now recovering after this catastrophe. One of the most important ways to predict a new disaster is to determine the rate of ice accumulation of the new glacier and to monitor the glacier volume regularly, since its trigger mechanisms have not yet been fully studied. Recent changes of the Kolka Glacier were investigated by means of ground stereoscopic photography. The field works were carried out in 2014, 2016 and 2017. Shooting was made manually with a digital camera Canon 5D Mark II (without using a tripod) at arbitrary points, the distance between which did not exceed 100 m. The reference points were placed on the elevated relief forms on the glacier surface and coordinated by a differential GNSS receiver in the "fast static" mode. Laboratory processing of the photos was performed using Agisoft Photoscan software in automatic mode, except for the procedure of identification of reference points on stereo images. The processing made possible to obtain digital models of the glacier surface in Geo-TIFF format, the vertical error of which amounted to 0.7 m, while the horizontal one – 2.3 m. In 2014–2017, the maximal increase in height of the surface (up to 30 m) was recorded in the low part of the glacier tongue that was the result of advancing of the Kolka front along the ice-free surface. Mean annual increase in the surface elevation was equal to 2.2 m/year. Lowering of the surface in some areas may be explained by the slowing-down of the glacier flow rate, which led to the appearance of thermokarst. The glacier volume increased by 7.4±0.7 million m3. As a result, the glacier tongue advanced by 50–70 m. Average over 2014–2017 increasing in the surface elevation (2.2 m/year) was slightly smaller than in 2004–2014 (3 m/year). Quick growth of the Kolka Gacier contrasts sharply with decreasing of volume of the representative Caucasus, Djankuat and Garabashi, over the same period. По данным наземной стереоскопической съёмки в 2014, 2016 и 2017 гг. оценены изменения объёма ледника Колка, восстанавливающегося после гляциальной катастрофы 2002 г. Ледник продолжает расти несмотря на неблагоприятные для ледников Кавказа климатические условия. Высоты поверхности ледника увеличивалась в среднем на 2,2 м/год, что резко контрастирует с негативным состоянием большинства ледников Кавказа

Meso- and macrozooplankton communities in the Weddell Sea, Antarctica

The present paper describes composition and abundance of meso- and macrozooplankton in the epipelagic zone of the Weddell Sea and gives a systematic review of encountered species regarding results of earlier expeditions. Material was sampled from 6 February to 10 March 1983 from RV Polarstern with a RMT 1+8 m (320 and 4500 μm mesh size). In agreement with topography and water mass distribution three distinct communities were defined, clearly separated by cluster analysis: The Southern Shelf Community has lowest abundances (approx. 9000 ind./1000 m3). Euphausia crystallorophias and Metridia gerlachei are predominating. Compared with the low overall abundance the number of regularly occurring species is high (55) due to many neritic forms. Herbivores and omnivores are dominating (58% and 35%). The North-eastern Shelf Community has highest abundances (about 31 000 ind./1000 m3). It is predominated by copepodites I–III of Calanus propinquus and Calanoides acutus (61%). The faunal composition is characterized by both oceanic and neritic species (64). Fine-filter feeders are prevailing (65%). The Oceanic Community has a mean abundance of approximately 23 000 ind./1000 m3, consisting of 61 species. Dominances are not as pronounced as in the shelf communities. Apart from abundant species like Calanus propinquus, Calanoides acutus, Metridia gerlachei, Oithona spp. and Oncaea spp. many typical inhabitants of the Eastwind Drift are encountered. All feeding types have about the same importance in the Oceanic Community

Renyi Criterion Modification in Testing the Hypotheses About Acceleration Factor Meaning at Variable-Load Tests

This paper concerns the acceleration factor estimation at strenuous tests of products in case of unstable production process (different batches of the same products may be with different index of reliability).Kartashov has developed techniques for determining the invariant functional from batch to batch, which convert accelerated test results to the normal mode. Its highlight is to conduct socalled preliminary tests of one sample of products, including pre-tests in the variable mode. The standard procedure for the preliminary tests (examination) is as follows: testing the n groups of products, with m elements in each group, begins in the normal mode. As soon as one of the products in the group fails, tests of remaining products start in the accelerated mode. In addition to tests in the variable mode, there are also tests conducted in the constantly normal mode. As a result of such tests of products from one batch, an acceleration factor of strenuous tests is determined for this type of products for any batch.The described procedure has the following shortcomings:• tests duration in the normal mode is long and, as a result, is very much time-consuming and cost-demandable;• tests conducted in the variable mode to the failure of all the products have the same drawback.This paper proposes a method for conducting the preliminary studies. It does not require testing in the constant mode and, additionally, allows tests duration in the variable mode to be restricted by the moment of the first failure in the r group. To analyze the results of such tests the Renyi type criterion of homogeneity of two samples is suggested. A method for calculating the distribution of its statistics for the finite sample sizes is developed and implemented in the software complex. The asymptotic distribution of the statistics is given. The estimate of the acceleration factor is provided by its minimization. It is shown that for real sample sizes of products only exact distribution should be used, as the asymptotic distribution approximates satisfactorily the exact distributions starting with n 500.</p