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At present, of special interest are polymer composite materials reinforced with carbon fibers - carbon fiber-reinforced plastic, which have increased specific strength, rigidity, wear resistance, etc. The purpose of this research is to study the physical and mechanical properties of composite materials reinforced with carbon and aramid fibers. According to the obtained temperature dependences of σ and E, we have selected the optimal variant of the polymer composite material on the basis of a nano-modified epoxy binder reinforced with carbon fibers

—The agricultural landscape of Ivanovo oblast is now a sophisticated mosaic of a variety of types of lands in use and of abandoned lands at different stages of succession. This is mainly determined by the fauna, structure, and population dynamics of such open-field birds as waders. This paper reflects the correlation of the fauna and population of the waders of agricultural lands in Ivanovo oblast with such key factors in farming ecosystems as the stages of succession, haymaking, pasturage, and agricultural burning of vegetation. Twenty wader species have been noted on the agricultural areas of Ivanovo oblast, 13 of which are breeding, six species of which are typical inhabitants of overgrown agriculture lands (the lapwing, curlew, black-tailed Godwit, common redshank, common snipe, and great snipe). The moisture content of soil in a specific year is the determining factor for the common snipe to nest on agricultural lands; the species demonstrates no pronounced trends of population density related to succession processes, up to the development of shrub-arborous vegetation. The other species of waders actively populate unused, fallow lands at intermediate stages of the demutational succession, increasing their abundance just at the first stages and avoiding sites overgrown with shrub-arborous vegetation. The lapwing also inhabits lands in use, while other wader species avoid nesting on actively exploited agricultural lands. The common redshank and the great snipe somewhat avoid lands with haymaking sites. By means of correlation analysis, a positive correlation was tracked of the wader fauna and population on nonannual (irregular) spring burns of vegetation, which hold down succession at stages favorable for waders.

In order to verify possible environmental predictors of labor onset in severely continental climate by means of correlation, multi regression and dispersion analysis we studied associations between daily number of births, gestational length and meteorological factors during the year of 1998 in Barnaul city, south-western Siberia. The medical records of 1 154 pregnant women aged 15-43 who gave births to single fetuses of both sexes were analyzed. The weak correlations were stated between atmospheric temperature, pressure gradient and daily number of births: its daily frequency grew in days with high temperature and sharp decrease of pressure by means of labor with decreased gestation length especially in January and February, the period of Siberian anticyclone. No associations were found with relative air humidity, wind velocity, and oxygen air concentration. The major role of atmospheric pressure was suggested among the external factors additionally influencing internal causes for labor initiation. Possible physiological mechanisms of pressure influences on human body are discussed.

The X-ray diffraction method is used to study radiation-induced changes in the structure and phase state of a model Fe–5% Mo alloy after electron irradiation at room temperature and 400°C. The observed radiation-induced softening of the alloy is explained by a decrease in the Mo concentration in solid solution and an increase in the number of lattice defects. This conclusion is confirmed by the shift of the 200 diffraction maximum toward larger angles and its broadening. Irradiation leads to the oxidation of the alloy, and additional annealing at 400°C causes the formation of spinel Fe2MoO4 and alloy strengthening.

The SEE (Satellite Energy Exchange) mission was suggested and designed under NASA Project in 1992–2002 to make extremely accurate measurements on fundamental gravitation by observing the orbital perturbation of unconstrained orbiting test bodies in a femto-g to atto-g environment. The mission uses novel and original test body dynamics. Its broad objective is to support the development of gravity theory and its unification with other interactions by carrying out sensitive gravitational tests capable of discriminating among alternative theories. The SEE mission introduced and utilized new technology for near-zero-g environment creation, passive cryogenic temperature control, passive station-keeping capability, and non-contact sub-micron-accuracy distance measurements, all of which promise to have a wide variety of applications.

The gravitational D-dimensional model is considered, with l scalar fields, a cosmological constant and several forms. When a cosmological block-diagonal metric, defined on a product of an 1-dimensional interval and n oriented Einstein spaces, is chosen, an electromagnetic composite brane ansatz is adopted, and certain restrictions on the branes are imposed, the conformally covariant Wheeler–DeWitt (WDW) equation for the model is studied. Under certain restrictions, asymptotic solutions to the WDWequation are found in the limit of the formation of billiard walls which reduce the problem to the socalled quantum billiard on (n + l - 1)-dimensional hyperbolic space. Several examples of billiards in the model with {pmn} non-intersecting electric branes, e.g., corresponding to hyperbolic Kac–Moody algebras, are considered. In the classical case, any of these billiards describe a never-ending oscillating behavior of scale factors while approaching to the singularity, which is either spacelike or timelike. For n = 2 the model is completely integrable in the asymptotic regime in the clasical and quantum cases.

This paper is a brief review of integrable models of gravitation and cosmology in four and more dimensions which make up one of the proper approaches to studying the basic issues and strong field objects, the early and present Universe, and black hole (BH) physics in particular. The main results within this approach, obtained in the recent years by the research group founded by K.P. Staniukovich, are presented. Absolute G measurements and problems of its possible time and range variations, which are reflections of the unification problem, are discussed within these models. The choice, nature, classification and precision of determination of fundamental physical constants and their role in the expected transition to new definitions of basic SI units, supposed to be based on fundamental physical constants and stable quantum phenomena, are described. A need for further absolute measurements of G, its possible range and time variations is stressed. Themultipurpose space project SEE is shortly described, aimed at measuring G and its stability in space and time with a progress of 2–3 orders of magnitude against the present accuracy. It may answer many important questions posed by gravitation, cosmology and unified theories. A project of a laboratory experiment to test possible deviations from Newton’s law of gravity is also presented.

The influence of pulsed laser irradiation on mechanical properties of annealed and cold-worked pure aluminum is studied. Mechanical tests are performed by means of a miniaturized disk bend test technique using specimens with the diameter of 3 mm. It is established that laser irradiation does not influence the mechanical properties of annealed aluminum but leads to softening of cold-worked material. After 100 laser pulses, nearly complete recovery of aluminum strength occurs to the value characteristic of the annealed state. The plasticity of cold-worked aluminum is lower than that of annealed material and does not vary upon laser irradiation. Thermal and shock-wave mechanisms of laser impact are estimated, and it follows that, under the given parameters of irradiation, the main contribution to the variation of properties is that of shock-wave mechanism related to generation and propagation of acoustic waves which stimulate athermal annealing and recovery of dislocation structure.

Recent results of measurements of the Avogadro constant by the method of crystal silicon spheres in connection with the planned transition to a new definition of the basic SI unit, the mole, are discussed.

The role of the fundamental constants and of measurement data on the Planck and Avogadro constants, the kelvin, and the electrical charge in the planned transition to new definitions of the four SI base units (kilogram, mole, ampere, and kelvin) based on fixed values of these constants is discussed.

A class of multidimensional theories is identified in which the spatial and temporal variations in the gravitational constant and the fine structure constant have a common origin and are of the same magnitude. Arguments are presented in favor of the existence of these variations despite a lack of confirmed observational data on variations in the gravitational constant because of problems in constructing a unified theory of physical interactions and the well-known faint young Sun paradox. It is concluded that the gravitational constant probably depends nonlinearly on cosmological time.

The design of the high-voltage axial injection system for the DC-280 cyclotron that is being constructed at the Flerov Laboratory of Nuclear Reactions (FLNR) at the Joint Institute for Nuclear Research (JINR) is presented. The injection system will make it possible to efficiently inject ions of elements ranging from helium to uranium with the ratios of their atomic mass to the charge varying from 4 to 7.5.

Two families of composite black brane solutions are overviewed, fluxbrane and black brane ones, in a model with scalar fields and fields of forms. The metric of any solution is defined on a manifold which contains a product of several Ricci-flat “internal” spaces. The solutions are governed by moduli functions $\mathcal{H}_s $ (for fluxbranes) and H s (for black branes), obeying nonlinear differential equations with certain boundary conditions. Themaster equations for $\mathcal{H}_s $ and H s are equivalent to Toda-like equations and depend on a nondegenerate matrix A related to brane intersection rules. The functions H s and $\mathcal{H}_s $ , as was conjectured and confirmed (at least partly) earlier, should be polynomials in proper variables if A is a Cartan matrix of some semisimple finite-dimensional Lie algebra. The fluxbrane polynomials $\mathcal{H}_s $ were shown to be used for the construction of black brane polynomials H s . This approach is illustrated by examples of nonextremal electric black p-brane solutions related to Lie algebras A 2, C 2, and G 2.

Work on the redefinition of the kilogram and mole underway in many countries with experiments employing watt balances is analyzed. It is found that at present the reasons for the discrepancies in measurements of the Avogadro and Planck constants by different methods are not clear and that the required measurement accuracy has not been attained. Thus, studies with watt balances and crystalline silicon spheres must be continued in the framework of new projects.

The DC-110 heavy ion cyclotron for industrial production of track membranes has been developed and created at the Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research. The cyclotron is equipped with an electron cyclotron resonance ion source operating at a frequency of 18 GHz. The accelerator complex was put into operation in 2012 and 40Ar6+, 86Kr13+, and 132Xe20+ ion beams with a energy of 2.5 MeV/nucleon and intensity of 13, 14.5, and 10.5 μA, respectively, were produced. Irradiation of a polymer film was carried out on a specialized channel and track membranes with a high uniformity of pores were obtained. The DC-110 accelerator complex can produce up to 2 million square meters of track membranes per year.

Bianchi type I cosmological model in (n+1)-dimensional gravity with several forms is considered. When the electric non-composite brane ansatz is adopted, the Wheeler-DeWitt (WDW) equation for the model, written in a conformally covariant form, is analyzed. Under certain restrictions, asymptotic solutions to the WDW equation near the singularity are found, which reduce the problem to the so-called quantum billiard on the (n-1)-dimensional Lobachevsky space H^{n-1}. Two examples of quantum billiards are considered: a 2-dimensional quantum billiard for a 4D model with three 2-forms and a 9D quantum billiard for an 11D model with 120 4-forms which mimics SM2-brane sector of D=11 supergravity. For certain solutions, vanishing of the wave function at the singularity is proved., Comment: 14 pages, LaTex, no figures, several typos are eliminated

A brief review of theoretical models explaining the variation in the fine structure constant α in space and time is given. A method is described for constructing models in which variations in α and other fundamental physical constants, including the gravitational constant G, follow from the dynamics of extra space-time dimensions in the framework of a multidimensional theory of gravitation that is nonlinear with respect to curvature. An explicit example of such a model is constructed for explaining the observed spatial and temporal variations in α.

The latest high-precision experimental results and theoretical calculations to determine the value of the fine-structure constant α are analyzed. These indicate a possible increase in its value by approximately 0.5·10−8α compared with the CODATA data (2006). It is shown that this shift in the value of α may play an important role in the new system of units, including the solution of the problem of matching the results of measurements of the Avogadro and Planck constants obtained by different methods (in the Avogadro project and by means of the watt balance).

We review spherically symmetric solutions with a horizon in two models: (i) with scalar fields and fields of forms, and (ii) with a multi-component anisotropic fluid. The metrics of the solutions are defined on a manifold that contains a product of n − 1 Ricci-flat “internal” spaces. The solutions are governed by functions H s obeying nonlinear differential equations with certain boundary conditions. Simulation of black-brane solutions is considered, and the Hawking temperature is calculated. For the fluid solution, the post-Newtonian parameters β and Γ corresponding to the 4-dimensional section of the metric are found.

Main current problems of physics, gravitation and cosmology in particular are analyzed. Special attention is paid to results of the theory with extra dimensions and variations of fundamental physical constants. As an example the family of spherically symmetric solutions with horizon with multi-component anisotropic fluid is presented. The metrics of solutions are defined on a manifold that contains a product of n - 1 Ricci-flat "internal" spaces. A simulation of black brane solutions is considered. For the solution with the fluid matter the post-Newtonian parameters β and γ corresponding to the 4-dimensional section of the metric are found.

Some trends in research on the physics underlying metrology as the science of measurement are examined. The basic problems and the prospects for their solution are analyzed.

Studies of multidimensional models with different sources (models with S -branes, thin and thick brane worlds, Kaluza-Klein type models in curvature-nonlinear multidimensional gravity etc.) and their application to the cosmological constant, cosmological singularity, hierarchy and coincidence problems are presented. Their observational predictions: variations of fundamental physical constants, new types of black holes and wormholes are discussed.

We give a comparative description of different types of regular static, spherically symmetric black holes (BHs) and discuss in more detail their particular type, which we suggest to call black universes. The latter have a Schwarzschild-like causal structure, but inside the horizon there is an expanding Kantowski-Sachs universe and a de Sitter infinity instead of a singularity. Thus a hypothetic BH explorer gets a chance to survive. Solutions of this kind are naturally obtained if one considers static, spherically symmetric distributions of various (but not all) kinds of phantom matter whose existence is favoured by cosmological observations. It also looks possible that our Universe has originated from phantom-dominated collapse in another universe and underwent isotropization after crossing the horizon. An explicit example of a black-universe solution with positive Schwarzschild mass is discussed., Comment: 13 pages, 1 figure. 6 referenses and some discussion added, misprints corrected

We discuss possible variations of the effective gravitational constant with length scale, predicted by most of alternative theories of gravity and unified models of physical interactions. After a brief general exposition, we review in more detail the predicted corrections to Newton's law of gravity in diverse brane world models. We consider various configurations in 5 dimensions (flat, de Sitter and AdS branes in Einstein and Einstein-Gauss-Bonnet theories, with and without induced gravity and possible incomplete graviton localization), 5D multi-brane systems and some models in higher dimensions. A common feature of all models considered is the existence of corrections to Newton's law at small radii comparable with the bulk characteristic length: at such radii, gravity on the brane becomes effectively multidimensional. Many models contain superlight perturbation modes, which modify gravity at large scale and may be important for astrophysics and cosmology., Comment: Brief review, 16 pages, 92 references. Some description and references added

Recent results on integrable cosmological models with different matter sources in DD and 4D are presented and their main properties related to basic problems of modern cosmology are described, with billiards, S-branes, with arbitrary potentials and possible variations of Effective G in particular.

A large class of integrable cosmological models with two matter components is presented. The D-dimensional models on the space-time manifold [Formula: see text] are studied in the presence of 2 separately conserved barotropic perfect fluids. Such model are reducible to pseudo-Euclidean Toda-like system and integrable when their barotropic parameters satisfy some algebraic relations. Methods for integrating of pseudo-Euclidean Toda-like systems are based on the Minkowski-like geometry for characteristic vectors composed from the barotropic parameters. We also apply the methods for the spatially flat Friedmann-Robertson-Walker universe containing a perfect fluid and a minimally coupled self-interacting scalar field with a potential comprised of two exponentials.

We study a spatially flat Friedmann model containing a pressureless perfect fluid (dust) and a scalar field with an unbounded from below potential of the form \(V(\varphi ) = W_0 - V_0 {\text{ sinh(}}\sqrt {{\text{3/2}}} \kappa \varphi {\text{)}}\), where the parameters W0 and V0 are arbitrary and \(\kappa = \sqrt {{8\pi }G_N } = M_p^{ - 1} \). The model is integrable and all exact solutions describe the recollapsing universe. The behavior of the model near both initial and final points of evolution is analyzed. The model is consistent with the observational parameters. We single out the exact solution with the present-day values of acceleration parameter q0=0.5 and dark matter density parameter Ωρ0=0.3 describing the evolution within the time approximately equal to 2H0−1.

A family of generalized $S$-brane solutions with orthogonal intersection rules and $n$ Ricci-flat factor spaces in the theory with several scalar fields and antisymmetric forms is considered. Two subclasses of solutions with power-law and exponential behaviour of scale factors are singled out. These subclasses contain sub-families of solutions with accelerated expansion of certain factor spaces. The solutions depend on charge densities of branes, their dimensions and intersections, dilatonic couplings and the number of dilatonic fields., To appear in GRG

Black p-brane solutions for a wide class of intersection rules and Ricci-flat ``internal'' spaces are considered. They are defined up to moduli functions H_s obeying non-linear differential equations with certain boundary conditions imposed. A new solution with intersections corresponding to the Lie algebra A_3 is obtained. The functions H_1, H_2 and H_3 for this solution are polynomials of degree 3, 4 and 3, correspondingly. An example of A_3-solution with three 3-branes in 12-dimensional model (suggested by N. Khviengia et al) is presented., 11 pages, Latex, to appear in Phys. Lett. B

In the framework of 10-dimensional "Friedmann-Calabi-Yau" cosmology of superstring origin we show that the time variation of either Newton's gravitational constant or Yang-Mills one is unavoidable in the present epoch., 8 pages, no figures, Latex, to be published in Gravitation and Cosmology, 2014, Vol. 20, No 1

This topical review deals with a multidimensional gravitational model containing dilatonic scalar fields and antisymmetric forms. The manifold is chosen in the form M = M_0 x M_1 x ...x M_n, where M_i are Einstein spaces (i >0). The sigma-model approach and exact solutions in the model are reviewed and the solutions with p-branes (e.g. Majumdar-Papapetrou-type, cosmological, spherically symmetric, black-brane and Freund-Rubin-type ones) are considered., 63 pages, Latex, topical review, few typos are eliminated

We describe some new estimates concerning the recently proposed SEE (Satellite Energy Exchange) experiment for measuring the gravitational interaction parameters in space. The experiment entails precision tracking of the relative motion of two test bodies (a heavy ''Shepherd'', and a light ''Particle'') on board a drag-free space capsule. The new estimates include (i) the sensitivity of Particle trajectories and G measurement to the Shepherd quadrupole moment uncertainties; (ii) the measurement errors of G and the strength of putative Yukawa-type force whose range parameter λ may be either of the order of a few metres or close to the Earth radius; (iii) a possible effect of the Van Allen radiation belts on the SEE experiment due to test-body electric charging. The main conclusions are that (i) the SEE concept may allow G to be measured with an uncertainty of less tha 1 part in 107 and progress up to two orders of magnitude is possible in the assessment of possible Yukawa forces and (ii) Van Allen charging of test bodies is a significant problem but it may be solved by existing methods.

Project SEE (Satellite Energy Exchange) is an international effort to develop a space-based mission for precise measurements of gravitation. Gravity is the missing link in unification theory. Because of the unique paucity of knowledge about this, the weakest of all known forces, and because gravity must have a key role in any unification theory, many aspects of gravity need to be understood in greater depth. A SEE mission would extend our knowledge of a number of gravitational parameters and effects, which are needed to test unification theories and various modern theories of gravity. SEE is a comprehensive gravitation experiment. A SEE mission would test for violations of the equivalence principle (EP), both by inverse-square-law (ISL) violations and by composition dependence (CD), both at ranges of the order of metres and at ranges on the order of RE. A SEE mission would also determine the gravitational constant G, test for time variation of G, and possibly test for post-Einsteinian orbital resonances. The potential finding of a non-zero time variation of G is perhaps the most important aspect of SEE. A SEE mission will also involve a search for new particles with very low masses, since any evidence of violations of the EP would be analysed in terms of a putative new Yukawa-like particle. Thus, SEE does not merely test for violations of general relativity (GR); SEE is a next-generation gravity mission.

We study a D-dimensional cosmological model on the manifold M=R×M0×R×Mn describing an evolution of n+1 Einstein factor spaces Mi in a theory with several dilatonic scalar fields and differential forms admitting an interpretation in terms of intersecting p-branes. The equations of motion of the model are reduced to the Euler-Lagrange equations for the so-called pseudo-Euclidean Toda-like system. Assuming that the characteristic vectors related to the configuration of p-branes and their couplings to the dilatonic scalar fields can be interpreted as the root vectors of a Lie algebra of the type Am≡sl(m+1C), we reduce the model to an open Toda chain, which is integrable by the customary methods. The resulting metric has the form of the Kasner solution. We single out the particular model describing the Friedmanlike evolution of the three-dimensional external factor space M0 (in the Einsteinian conformal gauge) and the contraction of the internal factor spaces M1,...,Mn.

Project SEE (Satellite Energy Exchange) is an international effort to organize a new space mission for fundamental measurements in gravitation, including tests of the equivalence principle (EP) by composition dependence (CD) and inverse-square-law (ISL) violations, determination of G, and a test for non-zero G-dot. The CD tests will be both at intermediate distances (a few metres) and at long distances (radius of the Earth, RE). Thus, a SEE mission would obtain accurate information self-consistently on a number of distinct gravitational effects. The EP test by CD at distances of a few metres would provide confirmation of earlier, more precise experiments. All other tests would significantly improve our knowledge of gravity. In particular, the error in G is projected to be less than 1 ppm. Project SEE entails launching a dedicated satellite and making detailed observations of free-floating test bodies within its experimental chamber.

The block-orthogonal generalization of the Majumdar-Papapetrou type solutions for the sigma-model studied earlier are obtained and corresponding solutions with p-branes are considered. The existence of solutions and the number of independent harmonic functions is defined by the matrix of scalar products of vectors $U^s$, governing the sigma-model target space metric. For orthogonal $U^s$, when target space is a symmetric homogeneous space, the solutions reduce to the previous ones. Two special classes of solutions with $U^s$ related to finite dimensional Lie algebras and hyperbolic (Kac-Moody) algebras are singled out and investigated. The affine Cartan matrices do not arise in the scheme under consideration. Some examples of obtained solutions and intersection rules for D=11 supergravity, related D=12 theory and extending them $B_D$-models are considered. For special multicenter solutions criterions for the existence of horizon and curvature singularity are found., Comment: 22 pages, Latex. Resubmit. to Class. and Quantum Grav. Revised version

The D-dimensional cosmological model on the manifold $M = R \times M_{1} \times M_{2}$ describing the evolution of 2 Einsteinian factor spaces, $M_1$ and $M_2$, in the presence of multicomponent perfect fluid source is considered. The barotropic equation of state for mass-energy densities and the pressures of the components is assumed in each space. When the number of the non Ricci-flat factor spaces and the number of the perfect fluid components are both equal to 2, the Einstein equations for the model are reduced to the generalized Emden-Fowler (second-order ordinary differential) equation, which has been recently investigated by Zaitsev and Polyanin within discrete-group analysis. Using the integrable classes of this equation one generates the integrable cosmological models. The corresponding metrics are presented. The method is demonstrated for the special model with Ricci-flat spaces $M_1,M_2$ and the 2-component perfect fluid source.

Multidimensional gravitational model on the manifold M = M0 × ∏i=1n Mi, where Mi are Einstein spaces (i ≥ 1), is considered. The action contains m = 2n − 1 dilatonic scalar fields ϕ1 and m (antisymmetric) forms A1. When all fields and scale factors of the metric depend (essentially) on the point of M0 and any A1 is “proportional” to the volume form of submanifold Mi1 × … × Mik, 1 ≤ i1 < … < ik ≤ n, the σ-model representation is obtained. A family of “Majumdar-Papapetrou type” solutions are obtained, when all Mν are Ricci-flat. Relation of our generalized p-branes to usual intersecting p-branes is discussed.

The multidimensional cosmological model describing the evolution of n Einstein spaces in the presence of multicomponent perfect fluid is considered. We define vectors related to the equations of state of the components. If they are orthogonal with respect to the minisuperspace metric, the Einstein equations are integrable and a Kasner-like form of the solutions is presented. For special sets of parameters the cosmological model is reduced to the Euclidean Toda-like system connected with some Lie algebra. The integrable vacuum (1+5+5)-model with two 5-dimensional Einstein spaces and non-zero Ricci tensors is obtained. Its reduction to a (1+5+3+2)-solution is given. For a special choice of the integration constant and one of the spaces (M1 = S5) a non-singular solution with the topology \(R^6 \times {\text{ }}M_2\) is obtained.