Standard Technological Process Research Articles

Producing antifriction babbitt В83 layer by gas-dynamic cold spraying

The technological processing of antifriction layer from Babbitt by gas-dynamic cold spraying was carried out on the DIMET-403. The coating was sprayed on plain bearings for marine low- and medium-speed diesel engines, turbines, and shaft lines. Technical requirements for antifriction layer materials, standard technological processes of preparation, spraying, heat treatment, and quality control are also considered.

Effect of ZnO nanoparticles synthesized by the improved method on the antibacterial properties of cotton textile materials

The object of this study is imparting antimicrobial properties to textile materials made from natural fibers and their blends. The study is aimed at solving the problem of ensuring a prolonged antimicrobial effect of cotton-containing fabrics. The use of ZnO nanoparticles, synthesized by the simple resource-saving method, as part of polymer-colloidal finishing compositions for the fabrics finishing is proposed. The effectiveness of using synthesized ZnO to impart prolonged antibacterial properties to cotton fabrics was assessed by studying the morphology, chemical composition, and bactericidal activity of nanoparticles. ZnO nanoparticles were synthesized by direct precipitation method at low temperatures in a short time in an aqueous solution using zinc acetate dihydrate and sodium hydroxide as precursors. The average crystallite size calculated using the Scherrer method is 28 nm. The degree of crystallinity according to X-ray diffraction pattern is 93 %. Using scanning electron microscopy, the formation of nanoparticles of uniform size in the form of short rods was established and the successfully synthesized ZnO phase in the hexagonal wurtzite structure was confirmed. The chemical purity of the crystalline material was confirmed using energy dispersive analysis. The atomic percentages of the elements are 47.6 % and 52.4 % for Zn and O, respectively. Study of the inhibition zone around fabric disks treated with ZnO showed their high bactericidal activity against air microflora and the gram-negative bacterium P. aeruginosa. It has been established that the use of ZnO as part of a polymer-colloidal system based on the acrylic polymer ensures the resistance of bactericidal treatment to washing. The reported scientific results are of practical importance for improving the standard technological process for finishing cotton textile materials

Effect of nickel doping on the spectral sensitivity of silicon solar cells

In the modern industrial production of solar cells (SC), there is a growing trend to utilize “solar silicon” as the base material due to its cost-effectiveness. However, solar silicon possesses a drawback - it has a shorter lifetime of minority charge carriers (MCC), making it challenging to achieve high efficiency in solar cells. To address this limitation and improve the efficiency of solar cells based on “solar silicon,” two key objectives need to be met. Firstly, it is essential to increase the lifetime of photogenerated charge carriers. Secondly, there is a need to minimize both optical and electrical energy losses. To achieve an increase in the lifetime of minority charge carriers in SCs, a process called gettering can be employed. This process involves utilizing clusters of nickel atoms to trap uncontrolled impurity atoms. The paper presents the results of a study on the additional doping of silicon solar cells with nickel atoms, for factors affecting the long-wave and short-wave efficiency. Nickel doping has been shown to increase the efficiency of solar cells. It is determined that in the visible region of the spectrum the spectral sensitivity of a silicon solar cell doped with nickel is higher up to 25÷35% due to a decrease in surface recombination. Technological recommendations for nickel doping of single-crystal silicon solar cells are proposed to be combined without significant changes with the standard technological process for manufacturing solar cells.

Low-Density Particleboards Modified with Blowing Agents—Characteristic and Properties

Although lightweight particleboards have been commercially available for years, they still have a number of disadvantages, including difficulty to process, brittleness, low impact strength, and other mechanical resistance. The aim of the paper was to determine the possibility of producing particleboards of reduced density (dedicated for furniture industry) as a result of using blowing agents from the group of hydrazides, dicarboxamides, or tetrazoles, which were modifiers of the adhesive resin used for bonding the particles of the core layer of three-layer particleboards. The concept presents the possibility of producing low-density particleboards in a standard technological process by modifying the adhesive resin, which has not been practiced by others until now. Analysis of the results of testing the particleboards properties with various types of modifiers (blowing agents), glue content (high 10%/12% and low 8%/10%), differing in glue dosing method, and different particle sizes allowed concluding that the most satisfactory effect was found in particleboards made of the variant modified with p-toluenesulfonyl hydrazide. This variant was characterised by the highest mechanical properties (bending strength, modulus elasticity, and internal bond strength) with high dimensional stability. The presented technology proposal can be applied in the industry.

Damage evaluation of the power plants materials based on the AE model of material degradation under high-cyclic fatigue

Modern mechanical engineering products are expected to have an increased lifetime at reduced cost. In order to enable this development, new and improved methods of structural materials strengthening need to be found. Mathematical modelling of the mechanical behaviour of the products in the conditions of fatigue, taking into account various operational, design and technological factors does not provide the necessary accuracy and has to be verified in long-term tests. Therefore, development of a methodology for predicting the limiting state of the structural materials under the long-term periodic load by non-destructive control methods, in particular the acoustic emission (AE) method, remains topical.Within this work, custom-designed model samples of nickel- and titanium-based alloys, as well as carbon and alloyed steel have been studied in comparison. The samples were fabricated both in standard technological process and including ultrasonic surface hardening. Features of cyclic AE characteristics that are identical for different classes of materials with different technological inheritance are described. Based on the obtained results, the relationships between the informative parameters of AE and the criteria of the limiting state of the studied materials for power plants under the high-cycle fatigue conditions are established. This enables assessment of the effectiveness of the technological measures aimed at increasing the life of parts of the power plants, based on non-destructive AE control.

Research aspects of modeling and automated process control photopolymerization

This paper provides an overview of the state of existing systems of predictable control of the polymerization process. It includes a literature and patent survey of the presented mathematical models of the processes that occur during chemical polymerization reactions and analyzes techniques of controlling the processes of designing, manufacturing, modeling and construction of automated control systems. A critical analysis of existing modeling and control systems is given. The most promising software complexes ready for use in the process of designing of materials and products from photopolymers with predetermined structural properties have been identified. The analysis of a standard technological process as an object of control, by the example of the presented algorithm of the functioning of a particular production unit, showed the possibility of improving the existing automated systems of its control. By this example the authors prove the possibility of constructing automated process control systems, as well as those of photopolymerization, which will stabilize physical and chemical processes when manufacturing products from photopolymers. At the end of the research it was made possible to determine the purpose and objectives of further research of the authors aimed at creating the following complex: a software for the development of materials with specified structural properties; development of mathematical tools for calculation and modeling of photopolymerization processes; construction of automated control systems for technological processes of manufacturing products from photopolymer structural materials.

ВОССТАНОВЛЕНИЕ ВАЛОВ МАШИН КОМБИНИРОВАНИЕМ ЭЛЕКТРОМЕХАНИЧЕСКОЙ ОБРАБОТКИ С ПРИМЕНЕНИЕМ ПОЛИМЕРНЫХ МАТЕРИАЛОВ

Currently, one of the most acute problems of repair production is the lack of highly efficient, but at the same time easy-to-implement technological processes for restoring the landing surfaces of shafts and axles of machine mechanisms. The solution to this problem is in the combination of simple and inexpensive technological processes with the production of multilayer coatings with specified guaranteed physical, mechanical, rheological and tribotechnical properties, as well as in ensuring the necessary dimensional and geometric accuracy of the restored joints of parts. (Research purpose) The research purpose is in developing a typical technological process for restoring the landing surfaces of the shafts of machine mechanisms for rolling bearings by combining electromechanical processing with the application of polymer coatings. (Materials and мethods) The article presents the studies of the physical, mechanical and rheological properties of polymer materials and combined coatings on the AI-7000M breaking machine of GOTECH Testing Machines Inc. The UGN60R software package was used to process the obtained results. (Results and discussion) The article presents a mathematical model that allows us to describe the process of loading the combined coating of a worn part with the determination of its stress-strain state at the installation stage and during operation of the restored fixed joint. As a result, the load affects the change in contact pressures to a greater extent, and the volume modulus and the shear modulus of the polymer to a lesser extent. (Conclusions) A new standard technological process has been developed and tested for restoring worn-out landing surfaces of shafts for rolling bearings of transmission units of domestic and foreign tractors, cars, agricultural machinery, equipment of processing industries by combining electromechanical processing with a coating based on polymer compositions ANATERM-201 and Loctite 3472.

ПРОИЗВОДСТВЕННЫЕ РЕКОМЕНДАЦИИ ПО ПРИМЕНЕНИЮ ЭЛЕКТРОЛИТА ХРОМИРОВАНИЯ В УСЛОВИЯХ ПРЕДПРИЯТИЙ ПРИДНЕСТРОВЬЯ

The article provides scientifically based recommendations for the use of the developed cold self-regulating chromium-plating electrolyte in the restoration and strengthening of machine parts. These recommendations will help to effectively use the developed electrolyte and the stand-ard technological process of strengthening and restoring machine parts in production conditions, while eliminating defects and increased material costs when applying chrome coatings. They re-flect the features of performing operations that affect the level of reliability of the technological process (pre-machining, degreasing, electrochemical etching, etc.) and the deposition of high-quality chrome coatings with high adhesion strength.

Logical Description of the Basic Production Processes for the Development of a Construction Production Information Model

We considered the questions and problems of detailing the basic production processes for the proposed evolutionary model for the development of automation and control methods for all cycles of construction production in the paradigm of the element-by-minute and per-minute organization of construction work based on the BIM construction model andapproved standard construction and technological processes of creating a construction production product. This system includes the proposed work automation and organization methods, which will provide element-by-element planning of the construction of buildings with minute precision of planning detailing, based on the use of pre-developed, testedand approved standard technological processes of construction production, within the framework of the global work schedule. The implementation result of such a system is to obtain an actual facility at the construction site corresponding to the BIM design model of the building, element-by-element and detailed fixation of the technological, financial and time parameters of the actually performed work, as well as resources spent at all stages of construction production. BIM implementation at the stage of construction production will provide an opportunity for automated data exchange with all stakeholders in third-party areas, including interaction and programmatic data exchange with the state construction information system, state supervision authorities, manufacturers of construction materials and equipment, participants in joint financing of construction works and others.

Developing the Guard Ring Topology of Power Silicon Diodes with a Blocking Voltage of up to 6.7 kV

High-voltage fast recovery diodes (FRDs) are characterized by a small forward voltage drop and low power dissipation. The main characteristics of such diodes is the reverse blocking voltage or the breakdown voltage. The aim of this work is to develop a guard ring topology allowing us to obtain the maximum possible blocking voltage of the diode and definite localization of the breakdown place under the conditions of the standard technological processes and without using new materials or substrates. The topology of the high-voltage part of silicon fast recovery power diodes is developed to obtain the maximum reverse blocking voltage. The calculations are carried out in the TCAD environment in the structure editor of which we included a program for the automatic creation of device models with dimensions of about several millimeters. The arrangement of guard rings is calculated according to the proposed principle allowing us to obtain power diodes with different breakdown voltages. The topology is developed so that the breakdown occurs under the edge of the active region, which guarantees the absence of catastrophic failures of the device. Power fast recovery diodes manufactured according to the proposed topology have the maximum reverse blocking voltage within the range of 3.3–6.7 kV, which indicates the reliability of the calculation methodology.

TECHNOLOGICAL ASPECTS OF CREATING A FIBER-OPTIC NON-DESTRUCTIVE TESTING OF SANDWICH COMPOSITE STRUCTURES

The results of research on the formation of the system of built-in non-destructive testing of linings of composite three-layer structures by an optical method using fiber-optic sensors based on fiber Bragg gratings are presented. The features of creating an input/output zone for fiber-optic sensors as applied to three-layer composite structures are studied. Recommendations for ensuring the integrity and optimal functioning of the fiber-optic monitoring system as applied to a real three-layer composite structure are formulated. The following is shown. The process of creating an integrated control system of three-layer composite structures by an optical method using integrated fiber-optic sensors includes a number of operations to form a topology and to ensure the output of fiber-optic sensors from composite claddings in a single technological cycle of manufacturing the structure according to the standard technological process without significantly adjusting it, which is extremely important in relation to serial technologies. When developing the technology of integrating fiber-optic sensors into a three-layer composite structure, it was experimentally shown that from the point of view of survivability and preservation of the efficiency of the embedded control system, it is necessary to fulfill a number of requirements for the placement and output of fiber-optic sensors taking into account the characteristics of manufacturing, machining, and operation designs. Thus, it is advisable to place fiber optic sensors in the casings at least 5 mm from the intended edge of the structure, at least 2 layers from the outer surface of the structure and not less than 5 layers from the honeycomb core. The fiber bend radius should be at least 30 mm to prevent mechanical burst and sharp bending of the signal when it is bending. Fiber optic sensors are recommended to be placed between layers with a reinforcement scheme in the direction of the fiber optic sensor, however placement is also allowed between the fiber sensors and one layer with a different direction of reinforcement, while in order to prevent fractures, computation fiber optic sensors overlap is unacceptable, thus, between crossover fiber-optic sensors must be at least 2 layers of prepreg.

ANALYSIS OF THE QUALITY OF NATIONAL VACCINE AGAINST RUBELLA.

Until recently Rubella has been a wide spread infection. Thanks to vaccination against rubella, taking part in the global elimination program of "manageable infections" of WHO and adoption of the program "Elimination of measles and rubella in Russian Federation" the morbidity index of rubella has reached the sporadic level. One of the determining conditions of rubella elimination is application of high-quality vaccines that satisfy international standards. In Russian Federation, foreign rubella vaccines certified in our country were used for several years. In 2008, the commercial production of domestic vaccine began. It is widely known that the required quality of immunobiological medications is achieved using adequate production conditions and standard technological process. That is why during the production of domestic rubella vaccine, all the rules and requirements of Russian regulatory authorities and international recommendations are followed. In this article, a retrospective analysis of domestic vaccine against rubella according to laboratory options of quality in 2012-2017 is given. The results of the analysis show that the medication demonstrates stable high quality that is indicative of secure production technologies.

Development Algorithm of the Technological Process of Manufacturing Gas Turbine Parts by Selective Laser Melting

The technology of the selective laser melting (SLM) allows making products from powders of aluminum, titanium, heat-resistant alloys and stainless steels. Today the use of SLM technology develops at manufacture of the functional parts. This in turn requires development of a methodology projection of technological processes (TP) for manufacturing parts including databases of standard TP. Use of a technique will allow to exclude influence of technologist’s qualification on made products quality, and also to reduce labor input and energy consumption by development of TP due to use of the databases of standard TP integrated into a methodology. As approbation of the developed methodology the research of influence of the modes of a laser emission on a roughness of a surface of synthesized material was presented. It is established that the best values of a roughness of exemplars in the longitudinal and transversal directions make 1.98 μm and 3.59 μm respectively. These values of a roughness were received at specific density of energy 6.25 J/mm2 that corresponds to power and the speed of scanning of 200 W and 400 mm/s, respectively, and a hatch distance of 0.08 mm.

Vibratory-centrifugal strengthening’s influence on failure-free parameters of drilling pumps bushings

The object of research is finishing-strengthening technological operation and implementing its safety systems to provide indicators of reliability of the bores of drilling pumps. At the finishing and finishing-strengthening operations of technological processes for the manufacture of products, their quality parameters, operational characteristics and reliability indicators are formed, the connections between which are complex, multi-stage and not obvious. The methods of mechanical and thermal processing and coating application can’t provide reliability indicators of cylinder bores of drilling pumps. Advantages of the previously developed by the authors’ method of vibration-centrifugal strengthening of parts and machines consist in providing a high level of deformation energy, high productivity, simplicity, reliability, compactness and versatility of strengthening devices, the possibility of qualitative processing of internal surfaces of machine parts. In addition, technical requirements are provided, performance indicators are improved and product life is increased. But, not always effective were attempts to adapt Vibrating machines of volumetric processing for vibration-centrifugal strengthening of products. Therefore, in the course of this study, volumetric vibration processing equipment for vibration-centrifugal strengthening of cylinder bores of НБ32 drilling pump was adapted and a technological tool for its implementation was designed. For experimental studies, the material of the bushings made of steel 70 on steel 20 has been changed and their internal execution surfaces have been strengthened using vibrations. In the course of full-scale tests it was established that after the vibration-centrifugal strengthening of the cylinder bushings of the drilling pumps, the dynamics of the change in the reliability factor, conditional probability and the failure rate for vibration-strengthened bushings is better than for base bushings manufactured according to the standard technological process. This is explained by the intensification of the processing and the possibility of adjusting the technological parameters of the process: the amplitude of the oscillations, the processing time, etc. In addition, the average time between failures of the vibration-strengthening bushings made of steel 20 increased 1.65 times compared to the base bushings of steel 70. The paths for further research are marked in the direction of optimization of processing regimes and development of practical recommendations on the use of vibration-centrifugal strengthening with an unbalanced drive.

Pharmaceutical properties of two ethenzamide-gentisic acid cocrystal polymorphs: Drug release profiles, spectroscopic studies and theoretical calculations

The aim of this study was to evaluate the stability and solubility of the polymorphic forms of the ethenzamide (ET) – gentisic acid (GA) cocrystals during standard technological processes leading to tablet formation, such as compression and excipient addition. In this work two polymorphic forms of pharmaceutical cocrystals (ETGA) were characterized by 13C and 15N solid-state nuclear magnetic resonance and Fourier transformed infrared spectroscopy. Spectroscopic studies were supported by gauge including projector augmented wave (GIPAW) calculations of chemical shielding constants.Polymorphs of cocrystals were easily identified and characterized on the basis of solid-state spectroscopic studies. ETGA cocrystals behaviour during direct compressionand tabletting with excipient addition were tested. In order to choose the best tablet composition with suitable properties for the pharmaceutical industry dissolution profile studies of tablets containing polymorphic forms of cocrystals with selected excipients were carried out.

Mechanical Properties Of Traditional And Nanofibre Textiles

Abstract This study deals with a comparison of mechanical properties of a conventional yarn and a textile from nanofibres. The conventional yarn represents the textile objects with high degree of orientation of fibres and the textile from nanofibres represents the textile objects with low degree of orientation of fibres. The theoretical section is concerned with the issue of internal structure of plied yarn and resulting differences in the orientation and straightening of fibres and in utilisation of deformation properties of fibres in comparison to the referred nano textile. The experimental section describes the manner of realisation of both static and dynamic tests of conventional yarn and strips of nanofibres. The results show differences in the mechanical properties of conventional yarn and textile strip from nanofibres under static and dynamic loading conditions. The processing technology of conventional yarn has been verified in the long term. But textiles from nanofibres are a relatively new material and mechanical properties of the detected differences point out possible problems with their behaviour during standard technological processes.

A Commercial off-the-shelf pMOS Transistor as X-ray and Heavy Ion Detector

Recently, p-channel metal-oxide-semiconductor (pMOS) transistors were suggested as fit for the task of detecting and quantifying ionizing radiation dose. Linearity, small detection volume, fast readout, portability, low power consumption and low radiation attenuation are some of the pMOS advantages over PIN diode and thermoluminiscent dosimeters. A hand-held measurement system using a low power commercial off-the-shelf pMOSas the sensor would have a clear advantage due to the lower cost incurred by a standard technological process. In this research work, we tested the commercial device 3N163 regarding its behaviouras an X-ray sensor, as well as its possible application as a heavy-ion detector. To study the radiation effects of X-rays, a XRD-7000 (Shimadzu) X-ray diffraction setup was used to produce 10-keV effective energy photons. Heavy ions tests involved 12C, 16O, 19F, 28Si, 35Cl, 63Cu and 107Ag beams scattered at 15° by a 275 μg/cm2 gold target, which provide LETs (Linear Energy Transfer) from 4 to 40 MeV/mg/cm2. The signal readout was done using a 1 GHz oscilloscope with a 10-Gsamples/s conversion rate, high enough to permit the recording of transient pulses in the drain current. In this case, an ion can cause a current signal proportional to the ion beam used. Through this study it was found that a simple commercial pMOS device can be reliably used as a detector of X-rays as well as heavy ion detector.

Voltage-Tunable Artificial Gradient-Index Lens Based on a Liquid Crystal Loaded Fishnet Metamaterial

In this letter, a voltage-tunable gradient-index fishnet metamaterial is presented. The unit cells of the fishnet are loaded with nematic liquid crystal material providing a continuous tuning of each column of the array. By introducing a voltage gradient over the width of the fishnet, the phase distribution over the aperture can be tuned, and thus the radiation direction can be controlled. The beam-scanning capability is demonstrated by simulation and measurements, and their comparison is discussed. The maximum measured scan angle using an <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$8 \times 8$</tex></formula> array at a frequency of 27.5 GHz is <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$ \pm {5^ \circ }$</tex></formula> requiring a maximum tuning voltage of only 20 V. The presented prototype including the biasing scheme, fabricated with standard technology processes, features a low weight compared to conventional lenses.

Thin film integrated AMR sensor for linear position measurements

A simple anisotropic magnetoresistive (AMR) sensor for linear positioning is designed as integrated bridge structure and implemented based on standard technology processes and rotation of the initial anisotropy axis after the patterning of the resistors. The behavior of the separate resistors is investigated by varying the intensity (0 ± 5 kA/m) and direction (0°, 45°, 90° in respect to the initial anisotropy axis) of the applied magnetic field. The experimental results are compared with data from simulation based on detailed analysis of the energy profile. Good agreement is obtained at assumed declination of 15° between the anisotropy and geometrical axes of the resistors. It is shown that in spite of asymmetries and hysteresis observed at low magnetic fields at higher fields used usually for the purposes of automation the response of the structure is single-valued and stable.

UV Bandpass Optical Filter for Microspectometers

This paper describes the design and modeling of a UV bandpass optical filter for microspectrometers. The materials used for fabricating the multilayer UV filter are: silicon dioxide (SiO2), titanium dioxide (TiO2) and yttrium oxide (Y2O3). The optical filter shows a bandpass response wavelength in the range 230-280 nm, with a transmittance higher than 80%. Such a device is extremely suitable for optical detection of biological molecules with optical absorption or/and fluorescence in the UV spectral range. This UV optical filter can be built using post- processing after integrated-circuit and UV photodiode fabrication in a bipolar or CMOS technology. The dielectric multi-layer stack can be deposited on top of the UV photodiode after the standard technology process has been completed. The number of layers was optimized for 11 with all layers of a thickness acceptable for reproducible fabrication. The materials used for fabricating the UV filter are silicon compatible. Applications presented are in DNA solutions (to measure the optical density of these solutions at 260 nm) and in the detection of a gas flame in the presence of ambient light based on the different emission spectra in the UV.