Reliability Study of Metal-Oxide Semiconductors in Integrated Circuits.

This paper is devoted to the study of CMOS IC parameter degradation during reliability testing. The paper presents a review of literature data on the issue of the reliability of semiconductor devices and integrated circuits and the types of failures leading to the degradation of IC parameters. It describes the tests carried out on the reliability of controlled parameters of integrated circuit TPS54332, such as quiescent current, quiescent current in standby mode, resistance of the open key, and instability of the set output voltage in the whole range of input voltages and in the whole range of load currents. The calculated values of activation energies and acceleration coefficients for different test temperature regimes are given. As a result of the work done, sample rejection tests have been carried out on the TPS54332 IC under study. Experimental fail-safe tests were carried out, with subsequent analysis of the chip samples by the controlled parameter quiescent current. On the basis of the obtained experimental values, the values of activation energy and acceleration coefficient at different temperature regimes were calculated. The dependencies of activation energy and acceleration coefficient on temperature were plotted, which show that activation energy linearly increases with increasing temperature, while the acceleration coefficient, on the contrary, decreases. It was also found that the value of the calculated activation energy of the chip is 0.1 eV less than the standard value of the activation energy.

Reuse and Mechanochemical Processing of Ore Dressing Tailings Used for Extracting Pb and Zn.

The increasing accumulation of rock waste obtained due to ore processing and its environmental impacts, such as acid mine drainage and elevated concentrations of heavy metals in soils, necessitates the transformation of mining technologies based on the concept of circular waste management. The research is aimed at improving the parameters of the mechanical activation effect produced on technogenic georesources, as well as at expanding the application scope of disintegrators in the field of using the partial backfill of the mined-out space when developing stratified deposits. In this regard, the research purpose was to substantiate the parameters of extracting metals from enrichment tailings using their mechanochemical activation to ensure cyclic waste management. The research involved the application of three-dimensional interpolation methods used for processing the data and the graphical representation. As a result, the following was found to be characteristic of the waste of the Sadonsky mine management. The degree of extracting zinc from pre-activated tailings increases logarithmically when the H2SO4 concentration and the NaCl proportion decrease 3.5 times. The degree of extracting lead from the activated tailings increases according to the Fourier law when decreasing the NaCl mass concentration, and an optimal range of the H2SO4 (0.38-0.51%) proportion decreases six times. One of the key results of the research is the justification of expanding the scope of applying disintegrators in the case of a directed activation influence exerted on the components of the stowing strips. The obtained results expand the understanding of the mechanism of the influence of the mechanochemical activation of dry tailings on the reactivity unevenness when extracting several metals from them.

Improvement of Hybrid Electrode Material Synthesis for Energy Accumulators Based on Carbon Nanotubes and Porous Structures.

Carbon materials are promising for use as electrodes for supercapacitors and lithium-ion batteries due to a number of properties, such as non-toxicity, high specific surface area, good electronic conductivity, chemical inertness, and a wide operating temperature range. Carbon-based electrodes, with their characteristic high specific power and good cyclic stability, can be used for a new generation of consumer electronics, biomedical devices and hybrid electric vehicles. However, most carbon materials, due to their low electrical conductivity and insufficient diffusion of electrolyte ions in complex micropores, have energy density limitations in these devices due to insufficient number of pores for electrolyte diffusion. This work focuses on the optimization of a hybrid material based on porous carbon and carbon nanotubes by mechanical mixing. The purpose of this work is to gain new knowledge about the effect of hybrid material composition on its specific capacitance. The material for the study is taken on the basis of porous carbon and carbon nanotubes. Electrodes made of this hybrid material were taken as an object of research. Porous carbon or nitrogen-containing porous carbon (combined with single-, double-, or multi-layer carbon nanotubes (single-layer carbon nanotubes, bilayer carbon nanotubes or multilayer carbon nanotubes) were used to create the hybrid material. The effect of catalytic chemical vapor deposition synthesis parameters, such as flow rate and methane-to-hydrogen ratio, as well as the type of catalytic system on the multilayer carbon nanotubes structure was investigated. Two types of catalysts based on Mo12O28 (µ2-OH)12{Co(H2O)3}4 were prepared for the synthesis of multilayer carbon nanotubes by precipitation and combustion. The resulting carbon materials were tested as electrodes for supercapacitors and lithium ion intercalation. Electrodes based on nitrogen-containing porous carbon/carbon nanotubes 95:5% were found to be the most efficient compared to nitrogen-doped porous carbon by 10%. Carbon nanotubes, bilayer carbon nanotubes and multilayer carbon nanotubes synthesized using the catalyst obtained by deposition were selected as additives for the hybrid material. The hybrid materials were obtained by mechanical mixing and dispersion in an aqueous solution followed by lyophilization to remove water. When optimizing the ratio of the hybrid material components, the most effective porous carbon:carbon nanotubes component ratio was determined.

Production of Workpieces from Martensitic Stainless Steel Using Electron-Beam Surfacing and Investigation of Cutting Forces When Milling Workpieces.

The aim of this study was to investigate cutting force when milling 40 × 13 stainless steel samples obtained via electron-beam surfacing. The samples were obtained by surfacing the wire made from the martensitic 40 × 13 stainless steel. The microstructure of the samples and the hardness are discussed in the present study. Emphasis is placed on the study of cutting forces when handling the samples. The structure of the samples obtained by electron-beam surfacing consisted of tempered martensite. The average hardness of the samples was similar to the hardness obtained after quenching and tempering the samples-576 HV for horizontally printed workpieces and 525 HV for vertically printed workpieces. High-speed milling, high-efficiency milling, and conventional milling have been proven to be suitable for handling such workpieces. This study shows that an increase in milling width leads to a gradual decrease in specific cutting force. As the milling depth increases, the specific cutting force decreases intensively at first but then more slowly with time. Machining the workpieces made of the martensitic stainless steel and produced by electron-beam surfacing requires the use of purely carbide mills with a diameter of at least 12 mm. Using a high-speed steel as a tool material results in the rapid failure of the tool. The cutting conditions during the investigation allowed for a decrease in the temperature of the cutting edge, cutting force, and the low-rigid end mill bending. Therefore, this study has made it possible to select modes that allow for a reduction in the vibration of the lathe-fixture-tool-part system.

Provision of Rational Parameters for the Turning Mode of Small-Sized Parts Made of the 29 NK Alloy and Beryllium Bronze for Subsequent Thermal Pulse Deburring.

The increase in the share of physical and technical processing methods in the arsenal of deburring technologies used in modern production is associated both with the use of difficult-to-machine materials, such as beryllium bronze and the 29 NK alloy, and with the need to solve technological problems for the production of small-sized products with hard-to-reach surfaces. The aim of the study is to improve the processes of blade processing of small-sized parts made of beryllium bronze and the 29 NK alloy to provide rational conditions for thermal pulse deburring. Surface samples were experimentally obtained after turning in different modes on a CITIZEN CINCOM K16E-VII automatic lathe equipped with an Applitec micromechanics tool. The surface quality and burr characteristics were examined using a JEOL JIB-Z4500 electron microscope and a ContourGT-K optical profilometer. The program Statistica 6 allowed processing of the results. The relationship between the parameters of the turning mode and the thickness of the root of the burrs formed on the machined surface, the limitation of which is one of the conditions for the application of the thermal pulse method, was established. The obtained empirical regression dependencies establish a rational range of cutting mode parameters, and the implementation of the formulated recommendations for setting blade modes ensures deburring by the thermal pulse method in compliance with the requirements of drawing under maximum processing performance.

Modeling and Model Verification of the Stress-Strain State of Reinforced Polymer Concrete.

This article considers the prospects of the application of building structures made of polymer concrete composites on the basis of strength analysis. The issues of application and structure of polymer-concrete mixtures are considered. Features of the stress-strain state of normal sections of polymer concrete beams are revealed. The dependence between the stresses and relative deformations of rubber polymer concretes and beams containing reinforcement frame and fiber reinforcement has been determined. The main direction of the study was the choice of ways to increase the strength characteristics of concrete with the addition of a polymer base and to increase the reliability of structures in general. The paper presents the results of experimental and mathematical studies of the stress-strain state and strength, as well as deflections of reinforced rubber-polymer beams. The peculiarities of fracture of reinforced rubber-polymer beams along their sections have been revealed according to the results of the experiment. The peculiarities of fracture formation of reinforced rubber-polymer beams have also been revealed. The conducted work has shown that the share of longitudinal reinforcement and the height of the fibrous reinforcement zone are the main factors. These reasons determine the characteristics of the strength of the beams and their resistance to destructive influences. The importance and scientific novelty of the work are the identified features of the stress-strain state of normal sections of rubber-concrete beams, namely, it has been established that the ultimate strength in axial compression and tension, deformations corresponding to the ultimate strength for rubber concrete exceed similar parameters for cement concrete 2.5-6.5 times. In the case of the addition of fiber reinforcement, this increase becomes, respectively, 3.0-7.5 times.

Tailings Utilization and Zinc Extraction Based on Mechanochemical Activation.

The significant containment of the global mining industry is caused by the problem of the transition to sustainable metal extraction and the integrated use of technogenic raw materials from the tailings of ore processing. The modeling of metal leaching processes using mechanical activation of polymetallic raw material components is particularly important in expanding the application of mining tailings as inert fillers of filling mixtures. This study is aimed at detecting the rotor speed factor on the chemical and mechanochemical effect of zinc yield growth from polymetallic tailings of the mining industry. In this regard, the purpose of this study was to improve the modeling of metal leaching processes using mechanical activation by improving the compositions of the filling mixtures. The methodology of the work included several comprehensive studies: the mechanical activation of tailings during zinc leaching from pulp in the DESI-11 disintegrator; the activation of enrichment tailings and the formation of a filling mass with different parameters of the component composition; the curing of cubic samples and their testing on the IP-1250 press. The Vi Improved text editor was used to prepare the algorithms for deterministic methods of three-dimensional interpolation in the Python language. The experimental results were graphically displayed using Gnuplot. The study of the agitation leaching of the waste obtained from the Sadonskiy mining district results in the fact that the NaCl mass concentration decreased from 13 to 1% and the H2SO4 concentration stabilization within 0.5 to 0.6% led to a 3-time increase in the zinc yield from the pulp, according to the polynomial law (from 28 to 91%). The obtained results expand the idea of the mechanism of the strength gain by the filling mass under mechanical activation on the components of the filling mixture, as well as changes in the efficiency of zinc leaching at different ratios of two types of lixiviants (sulphuric acid and sodium chloride) in the leaching solution.

Thermal Pulse Processing of Blanks of Small-Sized Parts Made of Beryllium Bronze and 29 NK Alloy.

The presence of burrs on parts is not allowed in high-tech industries; there is a tendency to improve accuracy and quality and to reduce overall dimensions. A high proportion of operations are aimed at removing burrs in the labor intensity of release. Thermal pulse deburring machines are being developed and are applicable for deburring small-sized high-precision parts while providing additional processing conditions. A significant part of the electronic component base-coaxial radio components-is produced from beryllium bronze and the 29 NK alloy. It is not possible to prevent burr formation when cutting these materials. The conditions for deburring by the thermal pulse method are established in compliance with the requirements for deviations in the geometry of parts, for surface roughness and for ensuring maximum processing performance. These are restrictions on the thickness of the burr root, a variant of the arrangement of parts in the chamber of thermal impulse installation, which ensures the prevention of damage to parts during processing. Additionally, it provides access to a combustible mixture of all the surfaces of the parts; there is also a pressure value of the combustible mixture, depending on the characteristics of the thermal pulse installation, the total area of the treated surface, and the thermal conductivity of the materials for workpieces.

Comprehensive Studies of the Processes of the Molecular Transfer of the Momentum, Thermal Energy and Mass in the Nutrient Media of Biotechnological Industries.

This article puts forward arguments in favor of the necessity of conducting complex measurements of molecular transport coefficients that quantitatively determine the coefficients of dynamic viscosity, thermal diffusivity and molecular diffusion. The rheological studies have been carried out on the viscometers of two types: those with a rolling ball (HÖPPLER® KF 3.2.), and those with a rotary one (Rheotest RN 4.1.). The thermophysical studies have been performed using the analyzer Hot Disk TPS 2500S. The measurements have been taken in the temperature range of 283 to 363 K. The concentration of dry substances has varied from 16.2 to 77.7% dry wt. An empirical equation for calculating the density of aqueous solutions of beet molasses has been obtained. The diagrams of the dependence of the dynamic viscosity on the shear rate in the range of 1 s-1 to 500 s-1 at different temperatures have been provided. The diagrams of the dependence of the coefficients of thermal conductivity and thermal diffusivity on the temperature and the concentration of dry substances have been presented, and empirical equations for their calculation have been obtained. The findings can be used for engineering calculations of hydrodynamic and heat-exchange processes in biotechnological equipment.