Some advanced methods for alloy composition regulation at negligible consumption of slag-forming additives are suggested. When implementing the proposed technology, the slag functions as a protector and electric conductor, and redox processes are determined by the magnitude and the applied potential function. Both cathodic and anodic polarization of aluminum alloys in alundum and graphite crucibles is studied with the curves polarization method. The behavior of components of aluminum alloys is studied under external cathodic and anodic effects of the melt with a constant electric field. During the cathode polarization there is a significant decrease of Mg loss in the aging process of the melt; on the contrary, anodic polarization increases the loss in comparison with the melting without external electrochemical action. The content of Fe and Ni under anodic polarity of the melt is not reduced if it is compared to the melting without electrochemical action due to passivation. The elements at the end of the electrochemical series are mostly protected. Thus, copper is wasted less under the cathodic and, especially, anodic polarization.

 

The process of silumin modifying by introducing nanodispersed powders of intermetalliсs NiAl, FeAl, and composite powders of NiAl / 15% Al₂O₃ and Si / Al₂ O₃ obtained by the method of mechanically activated self-propagating high-temperature synthesis (MASHS) with addition of 10% tungsten or copper to increase the density was studied. It is shown that the developed modifier compositions make it possible to increase mechanical properties of silumin and to obtain improved values as compared with standards. The effectiveness of introduction of nanocomposite MASHS powders is explained by their activity due to destruction of the oxide surface film and creation of nonequilibrium state in the surface region during mechanical activation. With the introduction of all modifiers, in addition to the composite powder NiAl / 15 % Al₂O₃ , ultimate tensile strength of silumin increases. Maximum strength, ductility and hardness are achieved with insertion of MASHS Si/Al₂O₃ powders and addition of tungsten or copper. The introduction of modifiers containing MASHS powders results in changing in distribution, size and amounts of primary and eutectic silicon and improves homogeneity of silumin metal matrix. The use of tungsten and copper improves assimilability of the introduced modifying powders.

 

Coatings In₂O₃ + SnO₂ (ITO) and ZrO₂ – Ni – ZrO₂ – Cu – Ni – ZrO₂ deposited on glass and polymer substrates, are presented. Their shielding properties in the optical and radio frequency wavelength ranges have been studied. Samples with coatings 120(In₂О₃ +SnО₂ ) and 90ZrO₂ /8Ni/90ZrO₂ /22Cu/5Ni/35ZrO₂ have good shielding properties (98 % of electromagnetic emission is reflected in the range of 0.7…17 GHz). ITO-coating has low surface resistance of 8…9 ohms/ square per square in combination with high light transmittance (T ~ 90 %). However, in order to achieve these properties one needs to heat the substrate up to 300…400 °C. The coating 90ZrO₂ /8Ni/90ZrO₂ /22Cu/5Ni/35ZrO₂ has surface resistance of 2…3 ohms/square per square and light transmittance of about 60 %. These values have been obtained without heating of the substrate and, as a consequence, this coating may be deposited on temperature-sensitive materials such as polycarbonate. Moreover, since 90ZrO₂ /8Ni/90ZrO₂ /22Cu/5Ni/35ZrO₂ coating is a multilayer coating containing layers of pure metals that have high electric conductivity and magnetic permeability and ZrO₂ layers with high dielectric permeability it has higher shielding effectiveness than ITO alloy coating. It has been demonstrated that ZrO₂ – Ni – ZrO₂ – Cu – Ni – ZrO₂ coatings may be used for protection of display screens since they comply with the requirements of screens of information displays devices.

 

A method of design of polyethylene terephthalate track membranes with asymmetric (conic) pores shaped by ion-track technology was considered. The method consists of two main stages: irradiation by swift heavy ions and one-sided etching of latent tracks. The shape and dimensions of individual pores of track membranes were defined by scanning electron microscopy of surfaces and cross-sections of membranes prepared with different etching times. Based on these results, time dependencies of cone bases and apex diameters of asymmetrical pores were determined. The possibility of the membranes application for direct and reverse osmosis was determined according to the results of investigations asymmetric track membranes with conic shape pores by means of measuring of hydrophility, air and water performance. Based on the analysis of tensile strength under loading with slowly changing pressure, the maximum pressure value that the membrane could stare was determined, as well as the dependence of the strength characteristics on the samples porosity. Simulation study of osmotic processes in NaCl solution efficiency of the track membranes for the direct and reverse osmosis was demonstrated and the influence of membrane parameters on their performance and the degree of water purification was showed.

 

Searching of such ways of processing at which irrevocable losses of precious metal will be minimum is necessary during the work with precious metals. In this regard it is necessary to investigate the main physico-mechanical properties of precious metals: durability, hardness, elasticity, plasticity and their rust resistance; to define temperature effect of processing on mechanical characteristics of the obtained precious metal ingots. Besides it is necessary to know physical and chemical properties of the metals which are a part of alloy, their workability by methods of metal forming, and knowledge of such properties is especially important at manufacture of dentoprosthetic disks. As a result of researches it is established that when rolling a strip of gold alloy of 900 fineness from initial thickness 4 mm to 0.55 mm, there is an extraction of grains in the direction of rolling; ultimate strength of alloy of AuAgCu 900-40 increases almost twice. Further annealing at temperature of 650 °C for 3 minutes completely restores plastic properties of the alloy.

 

Joint preparation (root face), overmatched size of the gap, bad fit-up, misalignment, not completed removal of rust, oil and incorrect tack welds are main factorial parameters. Experiments were carried out to confirm theoretical results and to establish schematics of defects, which were formed in production welds when dominated factors were negative. Research as conducted during construction of technological pipelines of different size with shielded arc welding (SAW), GMAW in CО₂ and Ar + CО₂ and GTAW. Welding was performed at certified production welding laboratories in accordance with tasks of the State Programs in scientific research. Results confirmed data from previous study in statistical analyzing of defects occurring. It is concluded that negative factors of joint preparation are the cause of forming of defects structure which is unique, related to this only factor.

 

A geometry optimization method based on use of macros for finite-element analysis program ANSYS 10 ED / LS-DYNA was developed for system of series-connected flat springs used as elastic elements of catapult for launching unmanned aerial vehicles. Optimization criterion in this case is the condition of the maximum stroke of both flat springs with the minimum deviation from the symmetrical form with respect to spring midpoints. Dynamic optimization problem of compression and relaxation of flat spring system was reduced to quasi-static problem of system pre-compression and high-velocity dynamic problem of its relaxation, and it significantly reduced solution time. Solution to the first part of the problem was carried out by means of Implicit Solver of ANSYS 10 ED / LS-DYNA. Solution to the second part of the problem was obtained by means of Explicit Solver of ANSYS 10 ED / LS-DYNA based on previous part results. It was determined that optimum system in terms of stroke and deviations of symmetry of flat springs consists of identical springs which are symmetrical relative to section middles.

 

The role of automation of technological preparation of production to ensure the competitiveness of engineering products. At manufacturing of engineering products the determining factor of cost reduction is to reduce material consumption, primarily in the blank production (billets of machine parts need to have minimal allowances for further machining). The Maximum use of business waste metal can also reduce the consumption of metal. The technological possibilities of modern equipment for nesting has increased considerably. Experience of machine-building enterprises, which use equipment for cutting sheets, including specialized computer-aided manufacturing (CAM) for nesting, which fit the equipment, proves, that the utilization ratio of metal can be increased in average by 22...28 % when the specialized CAM for nesting is using. Analysis of specialized CAM for nesting, available on the market, shows that these software tools generally correspond to the modern scientific-technical level of developments of this type. However, they have some drawbacks. The peculiarities of software package “Module nesting” are considered. The methods of automation technology cutting of parts made of profile rolled metal, calculation of norms of material consumption and utilization are described. Algorithms of linear, rectangular shaped layouts, which are implemented in the software package “Module nesting” are shown.

Theoretical aspects of the implementation of electroplastic deformation for dynamic pinch-effect at elastic-plastic deformation of metals with the participation of self-magnetic field of current are considered. The redistribution of magnetic field intensity H in the surface layers of metal leads to ponderomotive effects in the form of dynamic pinch effect, which in addition to the electron-plastic action of the pulse current leads to a compression of the sample intrinsic magnetic field and the excitation of elastic vibrations of the skeleton of the crystal lattice, with a repetition frequency of current pulses at the front of their rise. Dynamic pinch effect creates ultrasonic vibration of the lattice system, thus changing the kinetics, and induced plastic deformation due to the increase of the oscillation amplitude of rectilinear dislocations and periodic changes of the position of the dislocation loops with a higher probability of detachment of dislocations from stoppers. At deformation above the yield limit, due to the pinch effect, magnetic field of a current diffuses into crystal, thus the rate of diffusion depends on the conductivity of the metal and the frequency of the current. At the same geometry of the samples, the pinch effect is stronger for materials with high electrical conductivity. For practical use of the technology of electroplastic deformation, especially in the processing of metals by pressure by drawing, rolling and so on, it is necessary to consider physical conditions of the creation of the ponderomotive effects in relation to particular technologically important materials.

 

Technical ability to use the VVER-1200 spent nuclear fuel as a source of γ-radiation to solve radiation technology problems is substantiated. The technology area for these sources is limited to the problems which do not require large absorbed doses. EGSnrs program is used to determine the absorbed dose in irradiated materials from the spent fuel assemblies (SFA). This program is a computer code system, which forms a versatile package for simulation by Monte Carlo method the bound transfer of electrons and gamma-rays with energy above a few keV. The design of the radiation installation with the irradiator based on the SFA or composed of a number of fuel rods is proposed. The irradiator is located on the bottom of the pool and can be raised above the water level, or remain under its surface, if necessary. This layer of water plays a role of the shield and decreases neutron activation of irradiated material to a safe level. In some cases, boric acid dissolved in water allows reduction of the thickness of the water layer. Results of the evaluation of materials irradiation time and the thickness of the water shield are presented.

 

A four-mirror planaanastigmat calculation method is presented. Design feature of new mirror composition is existence of the afoсal scheme from the first two mirrors. The first and fourth mirrors can be combined into one unit (double mirror) which frame is an objective aperture. Different variants of designs are found; parametric characteristics of various modules are given. Seidel coefficients are described and the formulas of third order aberration polynomials are obtained. The correction factors of spherical aberration, coma, astigmatism are determined. Aberration correction is carried out at the expense of an asferization of smooth surfaces. The plane – field anastigmats are discussed; сlassification analysis by type of circuit decisions is executed for the purpose of obtaining a flat image field. A model of aberrational parametric algorithm of a new mirror plane – field anastigmat composition with a double mirror is developed. The system summary graphic and design factors have been presented. The problem on protection of the image plane from the foreign light has been considered. A light-gathering system (relative aperture D/f´ 1 : 1) consisting of four mirrors with a large field of view (near 2 w = 15^o ) has been developed. The system proposed provides a stable correction of aberrations in the field of view: in the setup plane, the circle of confusion is equal to 0.1 mm at the center and does not exceed 0.05 mm, with a small back-ground exceeding this limit at the edge. The image curvature is corrected and the astigmatism does not exceed 0.05 mm. The absence of chromatic aberrations, high resolving power, and acceptable conditions for disposition of receiving apparatus in the new mirror plananastigmat composition proposed allow it to be widely used. The objective proposed can be used in thermal imaging as well as optical devices operating in the infrared region of the spectrum.

 

A method of assessing of normative protection indicator of speech signal by the criterion of speech intelligibility at high noise level in the band of speech signal, equal to intelligibility, by means of complex measuring signal with a large base, is substaniated. The advantage of the complex measuring signal with a large base over harmonic measuring signal when assessing protection of speech data leakage channels is shown. Voice signals in digital form along with voice signals in analog form are widely used. It is necessary to find mathematical relation between bit-error probability and speech intelligibility for voice signals in digital form. It is also necessary to establish mathematical relation between compound signal with large base and harmonic measuring signal. The main purpose of the study is to establish a normative characteristic of leakage protection of voice signals on the base of determined mathematical relations. The given mathematical relations will allow realizing the automated measuring system for estimation of security of the confidential information transformed into the analog and digital form, in channels of its leak.