3D SLAM from stereoimages

A method of visual navigation by stereoimages for autonomous underwater vehicles is suggested. Two modifications of the method are considered. The first one is based on integration of measurement data of onboard navigation system with visual data. The second modification relies on the use of a six-cloud computation scheme. Results of computational experiments with model data are presented.     

Oxygen transport in the system niobium-uranium dioxide

Luch Technological Society. Translated from Atomnaya Énergiya, Vol. 71, No. 1, pp. 62–64, July, 1991.     

Structure formation in the heat treatment of alloy steel bar

The structure formation in 42Cr4Mo2 electrosteel on continuous cooling is studied. The results are presented in the form of a thermokinetic diagram. It follows from the diagram that bainite structure is predominantly formed in thermochemical treatment with cooling of the rolled steel at a mean-mass rate of 0.4–1.0°C/s, while ferrite-pearlite structure is mainly formed at rates less than 0.4°C/s. The influence of the treatment temperature and time on the structure and properties of the chromomolybdenum steel is investigated. If the cooling rate after hot deformation is increased by a factor of 1.6, the proportion of bainite in the metal is greater. In subsequent annealing with isothermal holding at 650–680°C, the bainite accelerates the spheroidization of the carbides. Consequently, the holding time may be reduced from 6.5 to 4 h, with consequent energy savings but without loss of metal quality.     

Thermomechanical treatment of high-carbon wire rod in the 150 high-speed wire mill at Belorussian Metallurgical Plant

The introduction of a reduction and calibration unit at a wire mill is recommended for the production of high-carbon wire rod subjected to thermomechanical treatment with controlled rolling and cooling. By this means, the fluctuation in the mechanical properties may be reduced. In addition, the decarburized layer will be thinner and uniformly distributed over the perimeter of the wire rod. As a result, the plasticity of the wire rod in subsequent processing is improved, while the formation of quench structures at the wire surface in high-speed drawing is practically eliminated.     

Studying the Chemical and Energy Engineering Process of the Strengthening Calcination of Phosphorite Pellets Containing Free Carbon

The chemical and energy engineering processes of sintering and calcination, which are of practical importance in the chemical and energy engineering system of the thermal treatment of phosphorite pellets containing free carbon, have been studied. They are thermally activated processes that occur in phosphate raw materials during heating. Some results of thermogravimetric, thermomechanical, structural, and microray analyses have been presented. The multifactor dependence of the sintering and calcination of coke-containing phosphorite pellets has been revealed. The dependence of the strength of phosphorite pellets and the degree of coke burnup on the temperature and the coke content in different heating regimes and the change in the weight and relative expansion of the material of pellets in oxidative and neutral media depending on the coke content and the heating rate have been established.     

Thermodynamics of chemisorption of sulfur from thiocyanate on nickel during electrochemical passivation

The effect of potassium thiocyanate content in an aqueous H₂SO₄ solution on the activation potential of a passive film formed on the nickel surface is studied. Based on the results, a thermodynamic model of chemisorption in electrochemical passivation of nickel in an aqueous H₂SO₄ solution containing surface-active KSCN thiocyanate additive is proposed. In the model, the formation of a NiO-NiS film is considered as a result of the equilibrium processes at the interfaces of the Ni|NiO-NiS|H₂O, SCN^? system. The total Gibbs energy of the chemisorptive phase formation of NiO-NiS solid solution is determined by partial chemisorptive formation energies of NiO and NiS. In turn, partial formation energy of either component is estimated as a sum of the Gibbs energy of the chemical formation of the component and the surface Gibbs energy of nickel, which depends on the KSCN concentration in the solution in the case of NiS formation. The system can be controlled due to the relation between the Gibbs energy and Flade electrode potential. As was experimentally found, the latter value determines the quantitative NiO: NiS ratio in the passive film.     

Nucleotide and actin binding properties of the isolated motor domain from Dictyostelium discoideum myosin

Nucleotide and actin binding properties of the truncated myosin head (S1dC) from Dictyostelium myosin II were studied in solution using rabbit skeletal myosin subfragment 1 as a reference material. S1dC and subfragment 1 had similar affinities for ADP analogues, epsilon ADP and TNP-ADP. The complexes of epsilon ADP and BeFx or AIF4- were less stable with S1dC than with subfragment 1. Stern-Volmer constants for acrylamide quenching of S1dC complexes with epsilon ADP, epsilon ADP.AIF4- and epsilon ADP.BeFx were 2.6, 2.9 and 2.2 M-1, respectively. The corresponding values for subfragment 1 were 2.6, 1.5 and 1.1 M-1. The environment of the nucleotide binding site was probed by using a hydrophobic fluorescent probe, PPBA. PPBA was a competitive inhibitor of S1dC Ca(2+)-ATPase (Ki = 1.6 microM). The binding of nucleotides to subfragment 1 enhanced PPBA fluorescence and caused blue shifts in the wavelength of its maximum emission in the order: ATP approximately ADP.AIF4- approximately ADP.BeFx > ATP gamma S > ADP > PPi. In the case of S1dC, the effects of different nucleotides were smaller and indistinguishable from each other. S1dC bound actin tighter than S1 (Kd = 7 nM and 60 nM, respectively). The actin activated MgATPase activity of S1dC varied between preparations, and the Vmax and K(m) values ranged between 3 and 7 s-1 and 60 and 190 microM, respectively. S1dC showed lower structural stability than S1 as revealed by their thermal inactivations at 35 degrees C. These results show that the nucleotide and actin binding of S1dC and subfragment 1 are similar but there are some differences in nucleotide and phosphate analogue-induced changes and the communication between the nucleotide and actin binding sites in these proteins.     

Generalized Model for Engineering and Controlling a Complex Multistage Chemical Energotechnological System for Processing Apatite-Nepheline Ore Wastes

Theoretical Foundations of Chemical Engineering - A comprehensive formulation for the problem of engineering applied to a multistage chemical energotechnological system for the production of...