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During long-term operation of elastic–plastic systems, inelastic deformations inevitably appear in the structure, leading to a decrease in the ultimate load that a building can resist. The question is how to estimate the remaining failure-free operating time of the structure if the operating strength parameters and the future load history are known. The theory of ideal elastoplasticity with a fixed yield surface cannot be applied to solve this problem. The current literature considers two approaches. The first involves models where a solid is defined by stresses and microstresses linked to deformations via constitutive equations. The second approach (isochronous plasticity) introduces the stress–deformation equation in a more complex integro-differential form than the elastic medium does. Although numerous problems have been studied via these models, a common mathematical theory has not been developed owing to the resulting nonlinear equations. This study offers a solution to the problem in a generalized framework based on variational principles and the assumption of defect accumulation. The concept of the damage accumulation tensor is introduced within the Schleicher–Nadai model depending on plastic deformation. This tensor is assumed to be determined by mechanical testing of the structural material. If the bearing safety factor against plastic failure exceeds unity at a certain time, then generalized solutions to the reviewed problem exist. In conclusion, the issues arising from the accepted problem setting that require further study are identified. [ABSTRACT FROM AUTHOR]

The results of simulation of radiation-chemical transformations in the primary coolant of a water-cooled water-moderated energy reactor (VVER) are presented. It has been shown that under conditions of intense irradiation, molecular nitrogen dissolved in the coolant exhibits chemical activity. The reaction of N2 with the excited hydroxyl radical initiates the formation of ammonia and nitrous acid. Further decomposition of ammonia produces only oxidized forms of nitrogen, with N2 acting as an intermediate product. Maintaining hydrogen and oxygen concentrations within normal limits in the ammonia water chemistry is possible only with constant dosing of NH3 and degassing of the coolant. In the case of water chemistry with H2 dosing (at the initial moment), on the contrary, a stationary regime is quickly established in the absence of disturbances, satisfying the requirements of VVER water chemistry standards. The difference between the two water chemistry systems is due to the presence of nitrogen in the NH3 molecule and its transformations as an element, regardless of the initial chemical form. [ABSTRACT FROM AUTHOR]

This paper studies the dynamics of proton flux in the South Atlantic Anomaly (SAA) region according to ARINA (was operated on the Resurs-DK1 satellite from 2006 to 2015) and VSPLESK (which was mounted on the ISS from 2008 to 2013) satellite experiment data. Both spectrometers have the same scheme. The SAA drift is determined by the position of the maximum flux of high-energy protons with energies in the range from 30 to 100 MeV at the altitude of the Resurs-DK1 satellite (about 580 km) and the ISS (380–420 km). Part of the time the instruments operated simultaneously. [ABSTRACT FROM AUTHOR]

Measurements of the angular dependencies of Electron Nuclear Double Resonance (ENDOR) were used for the analysis of the substitution site and local environment of the dominant axial Fe3+ center in LiNbO3 crystals. All components of hyperfine and quadrupole tensors for several shells of Li and Nb nuclei were determined. Since the found isotropic part of the hyperfine interaction of the iron electrons with the Li nuclei was small, it was justified to approximate the anisotropic part by the dipole-dipole interaction of electron and nuclear spins. From the comparison of the calculated and observed ENDOR spectra of the Li nuclei, it was derived that the Fe3+ ion occupies a Li site but is shifted from the regular Li position by 0.009 nm toward the octahedral structural vacancy. There is no evidence for the presence of any charge compensators in the nearest Li and Nb shells, which indicates a distant mechanism of excess charge compensation. ENDOR of Nb nuclei shows that there is a large isotropic hyperfine interaction due to the significant indirect transferred interaction of Fe3+ with nearest off axis Nb nuclei via O2- and polarization of Nb inner electron shells. [ABSTRACT FROM AUTHOR]

A mathematical model has been developed for the radiolysis of an aqueous solution containing the VVER primary coolant components ammonia and boric acid. The test results show that the average deviation of the model calculation results from experimental data does not exceed 35% when processing about 250 experimental data points. This model correctly predicts the temporal evolution of the VVER coolant quality indicators (concentrations of H2, O2, and NH3) and can be used to analyze their behavior at various parameters of the VVER core (temperature, power, boron content, etc.). [ABSTRACT FROM AUTHOR]

Nominally pure and gallium doped single crystals of potassium titanyl phosphate (KTiOPO4) have been studied by Electron Paramagnetic Resonance at low temperatures before and after irradiation. Irradiation with 20MeV electrons performed at room temperature and liquid nitrogen temperature caused an appearance of electrons and holes. Gallium impurities act as hole traps in KTiOPO4 creating Ga4+ centers. Two different Ga4+ centers were observed, Ga1 and Ga2. The Ga1 centers are dominant in Ga-doped samples. For the Ga1 center, a superhyperfine structure with one nucleus with nuclear spin 1=2 was registered and attributed to the interaction of gallium electrons with a phosphorus nucleus or proton in its surrounding. In both Ga1 and Ga2 centers, Ga4+ ions substitute for Ti4+ ions, but with a preference to one of two electrically distinct crystallographic positions (site selective substitution). The Ga doping eliminates one of the shortcomings of KTP crystals-- ionic conductivity of bulk crystals. However, this does not improve significantly the resistance of the crystals to electron and γ-radiation. [ABSTRACT FROM AUTHOR]

Electron Paramagnetic Resonance at low temperatures has been used to characterize potassium titanyl phosphate (KTiOPO4) single crystals grown by different techniques. Irradiation with 20MeV electrons performed at room temperature and liquid nitrogen temperature caused an appearance of electrons and holes. Platinum impurities act as electron traps in KTiOPO4 creating Pt3+ centers. Two different Pt3+ centers were observed, Pt(A) and Pt(D). The Pt(A) centers are dominant in undoped samples, whereas Pt(D)-in Ga-doped KTP crystals. Superhyperfine structure registered for Pt(D) centers was attributed to interactions of platinum electrons with 39K and two 31P nuclei in their surroundings. In both Pt(A) and Pt(D) centers, Pt3+ ions substitute for Ti4+ ions, but with a preference to one of two electrically distinct crystallographic positions. The site selective substitution can be controlled by the Ga-doping. [ABSTRACT FROM AUTHOR]

Radical polymerization of unsaturated alkoxy-NNO-azoxy compounds was explored. Polymethoxy-NNO-azoxyethene, the first energetic polymer based on alkoxy-NNO-azoxy compounds, was obtained, and its major characteristics were studied. Thermodynamic calculations show that poly(methoxy-NNO-azoxyethene) may be of interest as a polymer component of active binders for solid composite rocket propellants. [ABSTRACT FROM AUTHOR]

This paper reports the possibilities of predicting buckling of thin shells with nondestructive techniques during operation. It examines shallow shells fabricated from high-strength materials. Such structures are known to exhibit surface displacements exceeding the thickness of the elements. In the explored shells, relaxation oscillations of significant amplitude could be generated even under relatively low internal stresses. The problem of cylindrical shell oscillation is mechanically and mathematically modeled in a simplified form by conversion into an ordinary differential equation. To create the model, works by many authors who studied the geometry of the surface formed after buckling (postbuckling behavior) were used. The nonlinear ordinary differential equation for the oscillating shell matches the well-known Duffing equation. It is important that there is a small parameter before the second time derivative in the Duffing equation. This circumstance enables a detailed analysis of the obtained equation to be performed and a description to be given of the physical phenomena—relaxation oscillations—that are unique to thin high-strength shells. It is shown that harmonic oscillations of the shell around the equilibrium position and stable relaxation oscillations are defined by the bifurcation point of the solutions to the Duffing equation. This is the first point in the Feigenbaum sequence at which stable periodic motions are converted into dynamic chaos. The amplitude and period of the relaxation oscillations are calculated based on the physical properties and the level of internal stresses within the shell. Two cases of loading are reviewed: compression along generating elements and external pressure. It is emphasized that if external forces vary in time according to the harmonic law, the periodic oscillation of the shell (nonlinear resonance) is a combination of slow and stick-slip movements. Because the amplitude and the frequency of the oscillations are known, this fact enables an experimental facility to be proposed for prediction of shell buckling with nondestructive techniques. The following requirement is set as a safety factor: maximum load combinations must not cause displacements exceeding the specified limits. Based on the results of the experimental measurements, a formula is obtained to estimate the safety against buckling (safety factor) of the structure. [ABSTRACT FROM AUTHOR]

The possibility of covalent fixing of hydroxyl-containing photochromic compounds on the surface of polyurethane films containing excess isocyanate groups was studied. By comparing the spectral-kinetic characteristics of polyurethane films treated with solutions and films with chromene or spirooxazine derivatives introduced into the bulk polymer, it was concluded that in the first case the polymer swells and the photochromic compound becomes distributed predominantly in the bulk polymer rather than on the surface. [ABSTRACT FROM AUTHOR]

The environmental and economic efficiency of different energy sources - coal, gas, shale gas, oil, wind, sun, water, nuclei, and others - is examined. The environmental indices of different methods of power generation are presented, the contribution of different types of energy carriers to electricity production and their prospects are indicated, and the environmentally most acceptable energy sources for sustainable development are named. A comprehensive index of the environmental impact is proposed. [ABSTRACT FROM AUTHOR]

A thermodynamic analysis of a crucible reaction, which takes place in crucible induction furnaces, has been represented. A new diagram of a crucible reaction, with due account for partial pressures and activities of the participating components, has been suggested. For the first time ever, the electrochemical mechanism of a crucible reaction has been studied; the research has confirmed the correctness of the suggested diagram. [ABSTRACT FROM AUTHOR]

This paper demonstrates a fractal system of thin plates connected with hinges. The system can be studied using the methods of the mechanics of solids with internal degrees of freedom. The structure is deployable, and initially, it is similar to a small-diameter one-dimensional manifold, which occupies significant volume after deployment. The geometry of solids is studied using the method of the moving hedron. The relationships enabling the definition of the geometry of the introduced manifolds are derived based on the Cartan structure equations. The proof substantially makes use of the fact that the fractal consists of thin plates that are not long compared to the sizes of the system. The mechanics are described for solids with rigid plastic hinges between the plates, and the hinges are made of shape memory material. Based on the ultimate load theorems, estimates are performed to specify the internal pressure that is required to deploy the package into a three-dimensional (3D) structure and the heat input needed to return the system into its initial state. Some possible applications of the smooth 3D manifolds are demonstrated. [ABSTRACT FROM AUTHOR]

We studied the sensitivity of domestic proprietary human and animal cell lines from the collection of M. P. Chumakov Federal Scientific Center for Research and Development of Immuneand-Biological Products to infection with different enterovirus 71 strains. A cell system based on domestic proprietary permanent cell line 4647 was for the first time used for reproduction of four enterovirus 71 strains (BrCr, 42266, 42934, and 43374). It was shown that strain 4647 is the optimal cell substrate for enterovirus 71 reproduction. The titers of enterovirus 71 for all four strains considerably (by 2 lgTCID50/ml and more) increased during sequential passages in permanent cell line 4647. The prospects of using permanent cell line 4647 for creation of diagnostic and preventive preparations against 71 was demonstrated. [ABSTRACT FROM AUTHOR]

We studied the sensitivity of domestic proprietary human and animal cell lines from the collection of M. P. Chumakov Federal Scientific Center for Research and Development of Immuneand-Biological Products to infection with different enterovirus 71 strains. A cell system based on domestic proprietary permanent cell line 4647 was for the first time used for reproduction of four enterovirus 71 strains (BrCr, 42266, 42934, and 43374). It was shown that strain 4647 is the optimal cell substrate for enterovirus 71 reproduction. The titers of enterovirus 71 for all four strains considerably (by 2 lgTCID50/ml and more) increased during sequential passages in permanent cell line 4647. The prospects of using permanent cell line 4647 for creation of diagnostic and preventive preparations against 71 was demonstrated. [ABSTRACT FROM AUTHOR]

Structures of low-dimensional ZnS powders doped with Cu, Co, and Mn were studied using Mn ions as a paramagnetic probe. Particle sizes were 5-7 μm for ZnS:Cu, 7-10 μm for ZnS:Co, and 50-200 nm for ZnS:Mn. Spin-Hamiltonian parameters describing electron paramagnetic resonance spectra were obtained. Analysis of the spectra revealed that ZnS:Cu powder has cubic structure, ZnS:Mn powder has hexagonal structure with orthorhombic distortion, whereas ZnS:Co powder is a mixture of cubic and hexagonal phases in a 1:10 ratio. [ABSTRACT FROM AUTHOR]

We report a design solution for a highly reliable, low-noise and extremely efficient cryogenically cooled transmit/receive unit for a large antenna system meant for radio-astronomical observations and deep-space communications in the X band. We describe our design solution and the results of a series of laboratory and antenna tests carried out in order to investigate the properties of the cryogenically cooled low-noise amplifier developed. The transmit/receive unit designed for deep-space communications (Mars missions, radio observatories located at Lagrangian point L2, etc.) was used in practice for communication with live satellites including 'Radioastron' observatory, which moves in a highly elliptical orbit. [ABSTRACT FROM AUTHOR]

Changes in the structure of an electromagnetic field in a round screened waveguide are considered in a frame of reference moving with the velocity of wave propagation in the immobile frame. A method for calculation of the characteristics of a waveguide with a nonideal screening surface is proposed on the basis of a relativistic approach. [ABSTRACT FROM AUTHOR]

The effect of small additives of functionalized multiwall carbon nanotubes used as a modifier on the formation and properties of epoxy polymers cured with diaminodiphenyl sulfone is investigated. In the range of additive concentrations 0.01-0.50 wt %, there are extreme dependences of dynamic storage modulus and the glass-transition temperature on modifier concentration. As shown by electron microscopy and X-ray scattering, regions with increased packing densities of macromolecules are formed in the polymers in the presence of the modifier. The effect of the specific surface on the kinetics of curing of epoxy resins is observed. A mechanism controlling the formation of the epoxy matrix that is responsible for the inhomogeneous polymer structuring that defines the final properties of the polymers is suggested. [ABSTRACT FROM AUTHOR]

The article presents a study of the effect of heat loss without external gas exchange, focusing of the restrictions of the propagation of filtration combustion waves under high pressures of gaseous oxidant. It shows that heat loss can result to extinction in both complete and incomplete conversion modes of the solid reactant. It explores the limits of propagation limits of filtration combustion waves, critical values and the shape of parametric region.

Uniform composites of polyvinylpyrrolidone with the paramagnetic chromium (tris)oxalate complex (CHNO)Cr(CO)·11.56 HO and cation of quinoline spiropyran of the indo-line series were obtained for the first time. Their photochemical properties and static and superhigh-frequency dynamic magnetic characteristics were studied. The change in the ESR spectra under UV irradiation in films of polyvinylpyrrolidone containing photochromic paramagnetic was observed. [ABSTRACT FROM AUTHOR]

Chromenes functionalized with methacryl groups were synthesized and involved into the radical polymerization to obtain copolymers with ethyl acrylate. Comparison of spectral kinetic characteristics of poly(methyl methacrylate) glasses containing chromenes and photochromic copolymers as additives led to a conclusion that incorporation of a photochromic compound as a part of a copolymer into the polymeric glass increases efficiency of photocoloration of photochromic compounds in the polymeric layer. [ABSTRACT FROM AUTHOR]

The article presents information on the study conducted to determine the combustion mode of compacted metal powder samples. The combustion mode was determined from the front shape during combustion by using thermocouple measurements. The experiment determined the surface and the layer combustion mode of the porous niobium powder samples in a gaseous nitrogen atmosphere.

The electromagnetic stirring (EMS) of liquid metal in continuous-casting machines has become an integral part of the casting operation in world metallurgy and is done to improve the quality of continuous-cast sections and blooms. Electromagnetic stirring units may be installed in the mold, the secondary cooling zone (SCZ), and/or the final solidification zone (FSZ), depending on the requirements established for the continuous-cast metal and its quality. This article analyzes and substantiates the effectiveness of improving the quality of semifinished sections and rounds cast on semi-continuous casting machines with electromagnetic stirring of the liquid phase of the crystallizing ingot in the mold and the zone in which final solidification takes place. [ABSTRACT FROM AUTHOR]

The article discusses the effects of gas pressure towards the mechanism of propagation in spinning waves during filtration combustion. In a study concerning the surface modes of filtration combustion, it reveals that under certain conditions, the ring front breaks up to form a high-temperature zone on the sample surface. The numerical analysis indicates that spinning waves in filtration combustion has differed significantly from spinning waves in gasless combustion.

Mathematical modeling of electromagnetic mixing (EMM) in round semifinished products obtained on a semicontinuous caster at the Elektrostal’ Metallurgical Plant showed that the units developed for EMM in the mold and the zone where solidification of the casting is completed provide for mixing of the liquid phase of the ingot with maximum linear velocities in the range 0.5–0.9 m/sec. Calculated data on the solidification of semifinished products obtained by semi-continuous casting make it possible to determine the position of the liquid phase of the ingot in order to move the carriage of the EMM stator as solidification of the ingot proceeds. [ABSTRACT FROM AUTHOR]

Formation and evolution of the dislocation substructures in annealed and quenchedFe 0.6wt.%C - 1wt.%Mn - 2wt.%Sisteel with original structures of the pearlitic and martensitic types are examined thoroughly under high-cycle fatigue conditions using methods of transmission electron microscopy. The qualitative characteristics of a dislocation ensemble are determined and substructure gradients are revealed. [ABSTRACT FROM AUTHOR]

Develops a method of diagnosing heat exchangers from dynamic characteristics with the exchangers working in transient states under increasing or decreasing load. Equations describing the transient processes with reference to a steam crude oil heater; Thermal resistance; Metrical methods employed in Hamming space to represent the distance between a point representing a state with fault and the point corresponding to the state.

An analysis is made of trends and scientific-technical problems in the development of new cross-cutting shears (CCSs) for cutting flat-rolled products. The modernization of existing shears of this type is also included in the analysis. The article examines the main types of flying shears and electromagnetic plate stackers that have been designed by All-Russia Scientific Research, Planning, and Design Institute of Metallurgical Machinery (VNIImetmash) together with machine builders and metallurgical plants for use in CCSs. Specific equipment designs are discussed along with current developments in the modernization of existing flying shears and electromagnetic stackers. The article also reports on results obtained from commercial use of the equipment. [ABSTRACT FROM AUTHOR]

It was found by optical polarization microscopy and the EPR study that lithium niobate and tantalate crystals undergo irreversible lattice changes under anisotropic hydrostatic compression. Regions having different cell orientations were registered. The observed changes were explained in terms of "strain switching" of ferroelastic domains. Possible sequence of phase transitions in these crystals ( Pm3m\leftrightarrow R\ \bar{3}\ c\leftrightarrow R\ 3\ c ) and the symmetry of the condensed soft modes ( R 25 and Γ 15 , correspondingly) were obtained by the analysis of the Gibbs free energy under external pressure. [ABSTRACT FROM AUTHOR]

The paper reports on the study of the cave complex of the Holy Dormition Pskovo-Pechersky Monastery by the muography method. An original algorithm analyzing intersections of local maxima in angular distributions of muon fluxes, detected by different detectors, was developed to search for the hidden cavities. As a result, previously unknown underground spaces of significant size, with no direct access to them, were revealed. The obtained result, being of great interest for studying the history and archaeology of the cultural heritage site, demonstrates the unique capabilities of the muography method, which allows for investigating the internal structure of an object without its integrity violating. [ABSTRACT FROM AUTHOR]

Abstract. A new approach to the intrinsic and extrinsic defect subsystems, considering them as one integrated functional system, is developed for complex oxides. The strong interrelation of these subsystems becomes especially apparent when concentrations of both defect classes are comparable. A new parameter, reflecting the total intrinsic defect concentration, is introduced to determine the degree of crystal imperfection. The necessity of at least two calibrated samples - congruent and regularly ordered crystals - is substantiated. The accuracy by which the parameter can be determined can serve as a criterion in comparison of different methods of crystal characterisation. A procedure for crystal calibration by several physical characteristics is illustrated. Such a heuristic generalisation of the concept of mutual correlation of the whole defect system and the material only became possible on the basis of experimental and theoretical study of large numbers of LiNbO[sub 3] crystals. The spectra of EPR, NMR, ENDOR, and other properties of crystals with different compositions, diverse modifiers (K, Mg, ...), and various probe impurities have been analysed. It is found that crystals with vanishingly small concentration of intrinsic defects offer extraordinary informative opportunities. Their micro- and macroscopic properties are discussed. The developed ideas have a general character; therefore they should also be valid for other non-stoichiometric complex... [ABSTRACT FROM AUTHOR]

Resonance (frequency 1.4 cm[sup -1]) changes induced in the four-photon optical spectrum of water by a millimeter-wave electromagnetic field are observed experimentally. Comparison with the spectrum of ice in the range 0–2 cm[sup -1] shows that the action of such a field is of a structure-forming character. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A microbial community enriched with phosphate-accumulating organisms (PAO) was obtained in a laboratory sequencing batch reactor after 150 days of cultivation. Analysis of phosphate dynamics in the medium and the results of Raman scattering spectroscopy indicated the cycle of phosphate consumption and release during cultivation under oxic and anoxic conditions, respectively, which was typical of PAO. The highest content of intracellular phosphorus was 16.5 ± 0.15% of the dry ash-free biomass. Molecular genetic analysis and FISH revealed the taxonomic diversity of the microbial community, in which members of the "Ca. Аccumulibacter" group were the major PAO. [ABSTRACT FROM AUTHOR]

The transition process caused by an abruptly increased ammonium load (2.5-fold) on the microbial community of a sequential batch reactor carrying out nitrogen removal from the water via nitritation-anammox was studied. The community developed in the bioreactor at incoming ammonium concentration of 200 mg N/L removed 76.5% of the inflowing nitrogen and was satisfactorily described by the BioWin mathematical simulator with corrected coefficients. Abrupt increase of nitrogen load from 200 to 500 mg N/L resulted in ammonium concentration at the reactor outlet increasing from 27 to 280–290 mg N/L, with nitrogen removal efficiency dropping to 40%. The calculation using the BioWin simulator showed that the efficiency of the nitritation-anammox process should increase in the course of a month and stabilize at the level close to the original one (76.5%). However, experimental data did not support this calculation: no increase in efficiency was observed during this period. Changes in the structural and functional characteristics of the biofilms and aggregates, which were not accounted for in the model, were probably responsible for discrepancies between the experimental and calculated data. [ABSTRACT FROM AUTHOR]

This article addresses several problems that are related to the elastic stability of thin shells and that are due to inconsistencies between the experimental data and predictions based on the equations of the shallow-shell theory. The above contradictions are solved within the three-dimensional nonlinear theory of elasticity. In particular, the dynamic approach enables a prediction of the moment of bifurcation for very thin shells under momentless stress through the analysis of asymptotically built two-dimensional equations. Appearance and development of the dents and patterns in initially ideal shells that precede the buckling are also explained in this article. The dents represent solitonic waves that are detectible by acoustic devices. Therefore, it is possible to reduce the risk of failure of thin shells by using acoustic devices to monitor their conditions. The article covers two types of experiments with thin shells when the loads are close to buckling. These experiments enable to assess the safety buckling factor under technical operation of shells. [ABSTRACT FROM AUTHOR]

Formation of a community of phosphate-accumulating microorganisms in a laboratory sequential batch reactor (SBR) ensuring alternated aerobic and anaerobic conditions during periodic removal and addition of the medium were investigated. The bioreactor removed 50% phosphorus from the incoming medium after 22 days from the start-up. Microscopy and X-ray microassay revealed the of cells of diverse morphology that contained phosphorus-enriched granules. High-throughput sequencing of the 16S rRNA gene fragments carried out on days 0, 8, 15, and 22 showed changes in the community composition and its decreasing diversity. On day 22, approximately twofold increase of the relative abundances of Bacteroidetes (up to 43% of the 16S rRNA gene sequences) and Proteobacteria of the classes alpha (up to 15%) and beta (up to 27%) was observed. While at the onset of the reactor operation, typical PAOs related to "Candidatus Accumulibacter" (class Betaproteobacteria) constituted 0.2% of the community, they were not detected on day 22. The most likely PAO candidates were beta-proteobacteria of the genus Dechloromonas, the share of which increased from 0.7 to 11% by the time of the highest phosphorus removal from the inflowing medium. The relative abundance of heterotrophs of the genus Zoogloea (family Rhodocyclaceae) increased from 0.1 to 11.5%. [ABSTRACT FROM AUTHOR]

The mechanical characteristics of bacterial cellulose (one of the most promising cellulose-based nanomaterials) fundamentally depend on its moisture content. It has been found that the effect of aqueous solutions of alkali metal chlorides on its strength and deformation properties is determined by the mobility of water molecules in the near coordination spheres of cation hydration shells. [ABSTRACT FROM AUTHOR]

Bacterial cellulose is a product of the vital activity of some types of bacteria. In contrast to plant cellulose, it is characterized by high purity, strength, and elasticity. Together with nontoxicity and biocompatibility, these properties make bacterial cellulose to be applicable in biotechnology, medicine, and production of composites as a reinforcing component. The nanoscopic sizes of the structural units of bacterial cellulose provide it with a large specific surface area and, as a consequence, a pronounced dependence of many properties of a material on surface interactions with an environment. This review is devoted to discussing the structure and mechanical properties of bacterial cellulose, with especial attention being focused on its behavior in the presence of water and aqueous solutions. "Bacteria make no mistakes..." S. Gandlevskii [ABSTRACT FROM AUTHOR]

We have studied the EPR of Mn2+ ions in three samples of cubic nano-ZnS made by different technologies and having different nanoparticle sizes. Manganese occurs in the samples as an uncontrolled impurity. The EPR spectra can be described by two components: the spectrum of the Mn2+ in a cubic environment (Mn2+(C)) with parameters g = 2.0022 ± 0.0002, A = (–63.5 ± 0.5)·10–4 cm–1, 0 b4 ≥ 3.5·10–4 cm–1; and the spectrum of the Mn2+ ion associated with a planar lattice stacking fault (Mn2+ (F)), with parameters g = 2.0022 ± 0.0002, A = (–63.5 ± 0.5)·10–4 cm–1, b 2 0 = (–36 ± 1)·10–4 cm–1. The ratio of the number of centers Mn2+(C)/Mn2+(F) is 2.1:1 for sample 1 and 1.7:1 for samples 2 and 3. Planar stacking faults are typical lattice faults for cubic nano-ZnS. EPR of the Mn2+ ions lets us monitor the presence of these ions. [ABSTRACT FROM AUTHOR]

The imaging method based on the absorption and scattering of atmospheric muons (muography method) uses the natural flow of muons formed in the interactions of cosmic rays in the atmosphere. The method is at the junction of elementary particle physics and research in other very diverse fields of natural science, in particular, in archaeology. The paper presents the first results of an experiment to study a unique underground structure in the Holy Dormition Pskov-Caves Monastery, which is a cultural object with a centuries-old history. [ABSTRACT FROM AUTHOR]

The results obtained by measuring the efficiency of detection of charged particles (atmospheric muons) for a prototype of a polyvinyltoluene-based scintillation detector being created for the anticoincidence system of the Signal experiment on board the Interhelioprobe spacecraft are presented. These measurements rely on determining the ratio of the numbers of triple and double coincidences of pulses that arise as atmospheric muons traverse the detector system. [ABSTRACT FROM AUTHOR]

The OLIMPIYA project investigates tracks of galactic cosmic rays (GCR) in olivine crystals from two meteorites-pallasites of different exposure ages. Extended statistics (up to 21 743 processed tracks) enabled to reveal a difference between the charge spectra of heaviest nuclei registered in these pallasites versus those from detectors mounted on near-Earth orbit satellites, as well as a difference between the GCR spectra registered in the meteorites themselves. Comparison of the -element abundances in these spectra points that GCR fluxes from at least two rare cosmic nucleosynthesis events with enhanced production of these elements reached the Solar System during the exposition age of the older meteorite. Correlations of the experimental results with parameters of supernovae, asymptotic giant branches stars and neutron star mergers (NSM) are also discussed. [ABSTRACT FROM AUTHOR]

The effect of introduction of exogenous activated sludge (bioaugmentation) on the activity and composition of the microbial consortium carrying out the nitritation-anammox process in an SBR bioreactor was investigated. Two bioaugmentation strategies were tested: the exogenous sludge was added either immediately after inoculation with the anammox activated sludge or when the stable mode of nitrogen removal was achieved. The share of introduced sludge (by the amount of volatile dry matter) was 28‒35% of the total activated sludge mass. The growth conditions and community composition for activated sludges differed significantly: members of the genera "Candidatus Brocadia" and "Ca. Jettenia" were predominant in the aboriginal sludge, while "Ca. Kuenenia" and "Ca. Jettenia" predominated in the exogenous one. While bioaugmentation at the time of launching resulted in a 15% increase in nitrogen removal efficiency, this positive effect was short-lived (by day 46 of cultivation, the values of nitrogen removal efficiency in the control and experimental reactors were the same). Addition of exogenous activated sludge after the stable nitrogen removal mode was reached (day 53) increased the efficiency of nitrogen removal by 21‒35%, and this difference was maintained until the end of the experiment (90 days). The introduced anammox bacteria did not get acclimatized in the community of the SBR reactor; whatever was the method of their introduction, their abundance decreased to the minimum values. Our data indicate that the efficiency of nitrogen removal by the nitritation-anammox process may be enhanced by introduction of activated sludges differing in both the composition and the cultivation conditions from the aboriginal ones, either at reactor launching or into an actively operating bioreactor. [ABSTRACT FROM AUTHOR]

The applicability of a xenon γ-ray spectrometer based on a high-pressure (50 atm) xenon cylindrical ionization chamber to thermal neutron detection is discussed. The reaction of radiative capture of thermal neutron capture Xe( n, γ)Xe* followed by emission of 668-keV γ rays detectable by the spectrometer is used. The response of the xenon spectrometer with a sensitive volume of 0.2 L is analyzed. The measured thermal neutron detection efficiency is 0.08%. The advantage of the detector is its capability of simultaneously detecting both thermal neutrons and γ rays, which allows precise and high-efficiency identification of radioactive and fissile materials. [ABSTRACT FROM AUTHOR]

The method for the determination of fractions of terminal chains and chains bonded by physical or chemical knots from free induction decays (FID) and line shape was proposed on the basis of the earlier developed theory of NMR spectra in linear and cross-linked polymers. The density and topological structure of the effective polymer network and the characteristic correlation times of segmental motion of chains were determined for linear and branched poly(meth)acrylates at 130 °C from the coincidence of the theoretical and experimental FID curves and the line shape. A quantitative estimation of chain rigidity in the branched polymer with an increase in the brancher content was performed for the first time. [ABSTRACT FROM AUTHOR]

A new study of a historical object on the territory of the Russian Federation, the Holy Trinity Danilov Monastery, implemented by the muon radiography is presented. The method is based on the registration of changes in the cosmic muon fluxes during their passage through the object under study. Nuclear photoemulsions with unique spatial and angular resolution having the widest range of applications in experimental nuclear physics were used as experimental equipment. The experiment demonstrates a high efficiency of the method in the search for hidden objects, the presence of which on the territory of the monastery is confirmed by the results obtained. [ABSTRACT FROM AUTHOR]

One of the modern approaches to solving research and practical problems by studying internal structure of large natural and industrial objects on the base of muon radiography (muography) is presented. Muon is an unstable particle, but due to the relativistic time dilation effect, cosmic-origin muons with energies up to hundreds of TeV travel considerable distances before decaying. 7 Muon fluxes registered by emulsion detectors (arrows) added to 3D building model. In total, five emulsion detectors were used in this experiment, four of which were directed to the walls at an angle of 45, and one was directed upwards to measure the vertical muon flux. [Extracted from the article]

The stages of formation and development of activated sludge biofilm carrying out the anammox process in a laboratory sequencing batch reactor (SBR) with complete biomass retention on the carrier were investigated using light, epifluorescence, and electron microscopy. Light microscopy revealed biofilm formation on the carrier to occur within one week. Rod-shaped and filamentous microorganisms were the first to attach on the carrier and acted as a skeleton for biofilm formation, thus playing an important role in colonization of the carrier. Epifluorescence microscopy revealed physiologically active anammox bacteria of the genera Candidatus "Brocadia" and Ca. "Jettenia" in the biofilms. Selective autofluorescence of the colonies of anammox bacteria Ca. "Jettenia" was observed. This autofluorescence was probably caused by specific proteins in the extracellular polymeric substances (EPS), their synthesis and/or amount depending on the colony age and the physiological state of the cells. Structural organization of the colonies of anammox bacteria was investigated by electron microscopy. High-throughput sequencing of the 16S rRNA gene fragments revealed the presence of sequences affiliated with members of the phyla Chloroflexi, Bacteroidetes, Planctomycetes, and Proteobacteria in the biofilms. Apart from anammox bacteria, anaerobic and facultatively anaerobic organotrophs, stage I nitrifiers, denitrifiers, and sulfate reducers were detected. Members of the genus Ca. "Brocadia" were predominant among the anammox bacteria, probably due to better adhesion of their cells to the carrier or to their competitive advantage over Ca. "Jettenia" in the presence of organic acids (acetate and formate) in the medium. [ABSTRACT FROM AUTHOR]