The method of production of damask steel

The Russian term is "bulat" steel and to bulat is related the understanding of steel with high elastic and cutting properties, for which a unique microstructure, a patterned surface, is characteristic. To it was imparted special value and it was assumed to be a compulsory component of damask steel. The word "bulat" is of Iranian origin (pulad).In the modern understanding steel is a material with a certain chemical composition and damask steel does not fit under it.     

Calculation of regularization parameter in the problem of blur removal in digital image

The use of special digital image processing for removal of the blur which results quite often from a mutual relative motion of the optical sensor and object during the exposure is considered. The problem of blur removal from a digital image belongs to the class of incorrect problems, which means that it is impossible to obtain an exact solution resistant to small perturbations in the input data. Therefore, special methods should be invoked. The use of the Tikhonov regularization methods for solving the problem of blur removal from a digital image is demonstrated.     

On fractional faces of the metric polytope

The integrality recognition problem is considered on a sequence M _{n, k} of nested relaxations of a Boolean quadric polytope, including the rooted semimetric M _n and metric M _{n, 3} polytopes. The constraints of the metric polytope cut off all faces of the rooted semimetric polytope that contain only fractional vertices. This makes it possible to solve the integrality recognition problem on M _n in polynomial time. To solve the integrality recognition problem on the metric polytope, we consider the possibility of cutting off all fractional faces of M _{n, 3} by a certain relaxation M _{n, k} . The coordinates of points of the metric polytope are represented in homogeneous form as a three-dimensional block matrix. We show that in studying the question of cutting off the fractional faces of the metric polytope, it is sufficient to consider only constraints in the form of triangle inequalities.     

On one problem of integer optimization

A recognition problem of the following form is studied: to find put for the prescribed polyhedron whether the maximum of the linear objective function is achieved at its integral point. It is established that this problem is NP-hard in the general case and polynomially solvable in the class of rooted semimetric polyhedra.     

Measurement of the subcriticality of power-stressed reactors with an analog reactimeter

Conclusions A technique has been developed for measuring the effects of reactivity in a subcritical reactor with an analog reactimeter. It is based on the compensation of the current applied to the reactimeter input from the neutron detector. The compensation of current produced by neutrons of the subcritical multiplying assembly formalizes the algorithm for reactivity calculation, making it an adequate model of a reactor with a source and making it possible to determine the subcriticality without prior entry into the critical state. In this case the measurements are made in the presence of neutron sources characteristic of power-stressed reactors. The regular devices of the control and safety system could be used to produce unsteady variation of the neutron flux.All of this permits the proposed method to be extended to zero-power reactors and to power-stressed reactors. Once the subcriticality has been measured an analog of the neutron source is introduced into the reactimeter. This instrument measures the effects of reactivity in the subcritical state without the reactor being previously put into the critical state, monitors the entry of the reactor into the critical state by checking the reactivity, and makes all the measurements usually made with analog reactimeters. If the intensity of the source does not change during measurements (5–10 min) when chambers sensitive to rays (e.g., KNK-56 chambers) are used as neutron-flux detectors, then the accuracy of -ray compensation does not affect the results of the measurements.Translated from Atomnaya Énergiya, Vol. 45, No. 5, pp. 375–376, November, 1978.     

Experimental investigation of the current-induced breakage of metal-coated polymer films

We have experimentally studied the phenomenon of current-induced breakage of thin (∼20-to 30-nm-thick) metal films deposited onto poly(ethylene terephthalate) (PETP) and poly(propylene) (PP) substrates. Two mechanisms leading to the current-induced breakage of the metal film are established, which are characterized by different average threshold current densities: j _H ∼ 1.5 × 10¹⁰ A/m² and j _L ∼ 0.7 × 10¹⁰ A/m². The possible nature of these mechanisms is discussed.     

Testing a fiber-optic ionizing-radiation detector

A fiber-optic ionizing-radiation detector is composed of a scintillation sensor, an optical fiber, and a photodetector. Due to the miniature size and the high radiation resistance, the detector is capable of measuring the characteristics of powerful neutron and γ-ray fields with a high spatial resolution. A prototype of the detector has been tested using a ⁶⁰Co γ-ray source with a dose rate as great as 200 R/S. The dynamic range of dose measurements is no less than 10⁵. The detector signal is linearly dependent on the radiation dose rate. The ratio of the useful signal to the background due to radioluminescence of the optical fiber is presented for different types of scintillators.     

Assessing the Strategic Efficiency of Aviation Projects

Russian Engineering Research - The strategic efficiency of a project is defined. An approach to assessing the strategic efficiency of projects is outlined. This approach, incorporated in the State...     

Nanofluids for energetics: effect of stabilization on the critical heat flux at boiling

Investigation of aqueous nanofluids synthesized for the first time based on the natural alumosilicate attapulgite showed their high efficiency as heat-transfer agents and the ability to provide a more than twofold increase of the critical heat flux (CHF) as compared to that of the base liquid (pure water). It is shown that insignificant additives of sodium pyrophosphate, which produce disaggregation of nanoparticles and stabilization of attapulgite-containing nanofluids, significantly improve their thermal properties and heatexchange parameters. Several mechanisms are proposed for interpretation of the observed CHF growth. It is established that the use of attapulgite nanofluids not only allows higher CHF to be reached as compared to that of pure water, but also eliminates sudden onset of the boiling crisis.     

Interatomic interaction and vacancy mobility in FCC metals

A simple set of equations is derived to determine the Morse interatomic interaction potential parameters without any assumptions. These parameters are calculated for a model fcc crystal represented as 30 configuration spheres made of 1060 atoms surrounding a central atom. The dependences of these parameters on the number of surrounding atoms are obtained. The found parameters are used to calculate the energies of vacancy migration in 11 fcc metals using the proposed configuration sphere method.