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Every year, metallurgical plants emit hundreds of thousands of tons of harmful substances into the atmosphere. The remote sensing of flue gases from the chimneys of metallurgical plants is an urgent task for both industrial enterprises themselves and the enviromental control systems of nearby settlements. In this study, based on the results of the remote optical monitoring of emissions from chimneys of metallurgical plants of the PJSC "MMC 'Norilsk Nickel's'," Polar Division, the concentration of sulfur dioxide in flue gases is estimated. The measurements are carried out using infrared (IR) Fourier transform spectrometers operating in the 7–13 µm range with a spectral resolution of 4 cm–1. A new technology for remote optical sensing in the passive mode of flue gases from metallurgical plants is proposed, including measurements both on cross sections of chimneys and plumes. [ABSTRACT FROM AUTHOR]

Guar gum is a polymer that is widely used as a gelling agent for technological liquids in the petroleum industry. In this work, we have studied the potential for the environmentally friendly biodegradation of guar gum by enzymes of basidiomycetes for efficient disposal of oil industry wastes. We compared the enzymatic activity against guar gum of seven basidiomycete strains for the first time, namely Trametes hirsute MT-24.24, Lactarius necator, T. hirsute MT-17.24, Schizophyllum commune MT-33.01, Fomes fomentarius MT-4.05, Fomitopsis pinicola MT-5.21, and T. versicolor It-1. This comparison showed that the preparation based on the Fomitopsis pinicola MT-5.21 fungal mycelium at a concentration of 0.05% provides the most efficient decomposition of a hydraulic fracturing fluid containing guar gum. By varying the enzyme concentration in this fluid, it is possible to control the decrease in its viscosity over time. The developed enzyme preparation is an efficient and environmentally friendly guar gum biodegrader and can serve for processing waste fracturing fluids based on polysaccharides in order to reuse water resources. [ABSTRACT FROM AUTHOR]

The effect of iron and silicon impurities on the phase composition and properties of the Al–4.3Cu–2.2Yb quasi-binary alloy has been determined. In the microstructure of the cast alloy, in addition to the aluminum solid solution and dispersed eutectic ((Al) + Al8Cu4Yb), in which about 1% of iron is dissolved, the Al3Yb/(Al,Cu)17Yb2 and Al80Yb5Cu6Si8 phases are identified, which are not found in an alloy of a similar composition without impurities. After homogenization annealing at a temperature of 590°C for 3 h, the structure is represented by compact fragmented and coagulated intermetallic compounds 1–2 μm in size and a solid solution (Al) with a maximum copper content of 2.1%. The hardness of the deformed sheets significantly decreases after 0.5 h and changes slightly up to 6 h of annealing at temperatures of 150–210°C. After annealing at 180°C for 3 h, a substructure with a subgrain size of 200–400 nm is formed in the alloy structure. The softening after annealing of the rolled sheets at temperatures up to 250°C occurs owing to the recovery and polygonization processes and above 300°C owing to recrystallization. After annealing for 1 h at 300°C, the recrystallized grain size is 7 μm. The grain size increases to 16 µm after annealing for 1 h at 550°C. The Al–4.3Cu–2.2Yb alloy with impurities has a conditional yield strength of 205–273 MPa, a tensile strength of 215–302 MPa, and a relative elongation of 2.3–5.6% in the rolled alloy after annealing. Iron and silicon impurities do not lead to the formation of coarse lamellar intermetallic phases and do not reduce the ductility of the investigated alloy. [ABSTRACT FROM AUTHOR]

The effect of impurities on the phase composition and the properties of a new quasibinary Al–Cu–Gd alloy have been investigated. The microstructure in the cast alloy consists of an aluminum solid solution, a dispersed eutectic with the Al8Cu4Gd phase with approximately 1% iron impurity dissolved, and an (AlGdCuSi) phase with an approximate composition of Al80Gd5Cu8Si5. High-temperature homogenization at 600°С results in the fragmentation and spheroidization of the solidification-induced phases, including the silicon-containing phase. The annealing of cold-worked sheets at temperatures up to 250°C results in roughly the same softening associated with the recovery and polygonization processes in alloys with and without impurities. The structure is completely recrystallized after 1-hour annealing at 300°C and has an average grain size of 7.5 μm, which slightly increases to 11 μm after annealing at 550°C. The yield strength of the alloys rolled and annealed at 100–150°С is 227–276 MPa with elongation of 5%. Iron and silicon impurities have no negative effects on the microstructure and mechanical properties of this new alloy. [ABSTRACT FROM AUTHOR]

We present a brief history and the current status of research on gamma-ray bursts (GRBs), including observations at various GRB phases: the prompt emission, afterglow, supernova/kilonova, and the host galaxy. An overview of the known phenomenological features and theoretical models for GRBs is given. Problems, the solution of which is necessary for a successful study of the phenomenon of GRB, are discussed. [ABSTRACT FROM AUTHOR]

Topological models of graphene/CNT composite films are constructed. The films consist of tubes lying irregularly between graphene single layers parallel to them and covalently bound with graphene. The distance between the tubes is measured in graphene hexagons (H1 and H2) between ribs participating in the formation of covalent bonds. It is shown that only films based on zigzag (n, 0)-type tubes with an even number n are energetically stable. The film with the tube (10.0) and arrangement step 6/8 is most stable according to the investigations. It is found that the energy gap is present in the band structure of all studied film models and is in the range of 0.41–0.73 eV. [ABSTRACT FROM AUTHOR]

The prospects for using wastes from cellulose-containing feedstock for manufacturing a broad spectrum of motor fuel components (biodiesel, bioethanol, biogasoline) are examined. The possibility of biosynthesis of lipids similar in composition and properties to soy oil was demonstrated on the example of fungal strains Agrocybe aegerita and Lentinus edodes. These lipids can serve as an intermediate product for synthesis of biodiesel fuel due to the high content of higher fatty acid triglycerides. The results of catalytic processing of bioethanol from a wood substrate obtained after solid-phase cultivation of fungi in a mixture of aliphatic and aromatic hydrocarbons are reported. [ABSTRACT FROM AUTHOR]

Bolometric light curves for the afterglow resulting from the passage of a gamma-ray burst through a molecular cloud are computed. The profile and duration of the afterglow light curve depend strongly on the distribution of matter in the cloud, the degree of collimation of the gamma-ray radiation, and the observing conditions. The peak can be reached as soon as seven days (the gamma-ray burst is located at some distance from the center of a molecular cloud with small-scale density enhancements), or as long as one to three years (the gamma-ray burst is located at the center of a uniform molecular cloud) after the burst. The bolometric luminosity of the re-radiated signal can reach 6.5×1042 erg/s.© 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]

Observations of the afterglows of gamma ray bursts (GRBs) in different spectral ranges yield valuable information both about the nature of GRBs and about the properties of the surrounding medium. A powerful infrared (IR) afterglow has been observed at the site of the strong GRB041219. Here we interpret the observed IR afterglow as the result of a reprocessing of gamma radiation on dust in a cloud surrounding the GRB source. In this model we do not expect the appearance of a prompt optical afterglow which should be absorbed by the surrounding dust cloud. We estimate the collimation angle of the gamma radiation and obtain limits on the red shift (distance to the GRB source) by matching the model parameters to the experimental data. [ABSTRACT FROM AUTHOR]

The interaction of a powerful cosmological gamma-ray burst (GRB) with a dense molecular cloud is modeled. Two-dimensional gas-dynamical flows were computed for various configurations of the cloud. In the spherically symmetrical case, the gas velocity does not exceed ∼ 2 × 10³&radicE/1.6 × 1053;km/s. If the GRB precursor has an anisotropic wind, a conical cavity can form in the nearby region of themolecular cloud. The propagation of the gamma-ray pulse in this cavity leads to the formation of a rapidly moving hot clump of matter, with the gas velocity reaching 1.8 ×104 km/s for gammaray energy of E = 1.6×1053 erg. In all the computations, the velocity of the moving material ismuch lower than the velocity of light, the volume of gas affected by the motion is small, and the influence of the gas motions on the light curve of the optical afterglow is insignificant. [ABSTRACT FROM AUTHOR]

The motion with intersections of relativistic gravitating shells in the Schwarzschild gravitational field of a central body is considered. Formulas are derived for calculating parameters of the shells after intersection via their parameters before intersection. Such special cases as the Newtonian approximation, intersections of light shells, and intersections of a test shell with a gravitating shell are also considered. The ejection of one of the shells to infinity in the relativistic region is described. The equations of motion for the shells are analyzed numerically. [ABSTRACT FROM AUTHOR]

The evolution of stars with mass 5M⊙ with an initially cool neutron core (Thorne-Zytkow objects) is computed numerically, taking into account the heating of the neutron star by flows of heat released during the accretion of a surrounding envelope. The temperature of the neutron core does not rise to values at which the system could become unstable to rapid increases in the neutrino luminosity. In other words, the heating of the neutron core does not lead to a rapid collapse of the initial configuration. [ABSTRACT FROM AUTHOR]

Long duration gamma-ray bursts (GRBs), the brightest events since the Big Bang itself, are believed to originate in an ultra-relativistic jet breaking out from a massive stellar envelope. Despite decades of study, there is still no consensus on their emission mechanism. One unresolved question is the origin of the tight correlation between the spectral peak energy and peak luminosity discovered in observations. This Yonetoku relation is the tightest correlation found in the properties of the prompt phase of GRB emission, providing the best diagnostic for the radiation mechanism. Here we present three-dimensional hydrodynamical simulations, and post-process radiation transfer calculations, of photospheric emission from a relativistic jet. Our simulations reproduce the Yonetoku relation as a natural consequence of viewing angle. Although jet dynamics depend sensitively on luminosity, the correlation holds regardless. This result strongly suggests that photospheric emission is the dominant component in the prompt phase of GRBs. Yonetoku relation provides a diagnostic for the radiation mechanism in the prompt phase of gamma-ray burst (GRB) emission. Here, Ito et al. show the reproduction of this relation in 3D hydrodynamical simulations followed by radiative transfer calculations, which suggest the photospheric emission is the dominant component in the prompt phase of GRBs. [ABSTRACT FROM AUTHOR]