Pub Date : 2023-03-01DOI: 10.18698/0236-3941-2023-1-67-79
Astua A. V. Gonsales, K. A. Karnaukhov, T. S. Malishchuk, Y. Popov
Airbag pyrotechnic gas generators occupy a key position in the vehicle passive safety system with all the importance of the other components. Despite the abundance of various types of the airbags, single-stage pyrotechnic gas generators for the driver and passenger airbags are most interesting to the domestic vehicles manufacturers due to the budget cars leading positions in the domestic market. For proprietary design, development and production of the airbag gas generators, it is necessary to combine efforts of specialists in the chemical industry and in general engineering. At the same time, it should not be forgotten that production of the pyrotechnic airbag gas generators is subject to strict national and international regulation. Therefore, comprehensive system analysis of the pyrotechnic gas generators design by foreign manufactures used in the modern vehicles becomes important and necessary to form scientific and technical base for design and development of the proprietary commercial gas generators and localizing the full cycle of mass production of such devices in the territory of the Russian Federation. General classification of the airbag gas generators is provided, key features of the product design and production technologies for the main components of the dome-shaped solid fuel gas generator with a single-stage airbag response are considered, and technological schemes of the assembly processes and basic assembly operations are analyzed using the example of gas generators of different generations. Results of the study are of interest to the automotive industry specialists
{"title":"Design and Production Technology Features of the Domed Solid Fuel Gas Generators with Single-Stage Response of the Vehicle Passive Safety System","authors":"Astua A. V. Gonsales, K. A. Karnaukhov, T. S. Malishchuk, Y. Popov","doi":"10.18698/0236-3941-2023-1-67-79","DOIUrl":"https://doi.org/10.18698/0236-3941-2023-1-67-79","url":null,"abstract":"Airbag pyrotechnic gas generators occupy a key position in the vehicle passive safety system with all the importance of the other components. Despite the abundance of various types of the airbags, single-stage pyrotechnic gas generators for the driver and passenger airbags are most interesting to the domestic vehicles manufacturers due to the budget cars leading positions in the domestic market. For proprietary design, development and production of the airbag gas generators, it is necessary to combine efforts of specialists in the chemical industry and in general engineering. At the same time, it should not be forgotten that production of the pyrotechnic airbag gas generators is subject to strict national and international regulation. Therefore, comprehensive system analysis of the pyrotechnic gas generators design by foreign manufactures used in the modern vehicles becomes important and necessary to form scientific and technical base for design and development of the proprietary commercial gas generators and localizing the full cycle of mass production of such devices in the territory of the Russian Federation. General classification of the airbag gas generators is provided, key features of the product design and production technologies for the main components of the dome-shaped solid fuel gas generator with a single-stage airbag response are considered, and technological schemes of the assembly processes and basic assembly operations are analyzed using the example of gas generators of different generations. Results of the study are of interest to the automotive industry specialists","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80228321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18698/0236-3941-2023-1-97-126
Vladyslav Markov
Relevance of the article is determined by the need to improve power and dynamic performance of the thermal power plants and indicators of their fuel efficiency and toxicity of the exhaust gases. An integral part of these facilities are the automatic control and regulation systems that ensure coordination of the elements and systems of the combined thermal and power facilities in a wide range of their operating modes. The most important criteria in such elements and systems coordination are the indicators characterizing toxicity of the exhaust gases. Currently, thermal power plants based on the piston and combined internal combustion engines are widely used. Main areas of improving thermal power plants with the internal combustion engines and their automatic control and regulation systems were analyzed. For example, expanding their functionality including the exhaust gas purification systems control and the use of thermal power plants in adaptation to operate on the alternative fuels; improving the quality of control and regulation processes and minimizing the share of unsteady operating modes of the thermal power plants. Current level of systems for automatic control and regulation of the thermal power plants was evaluated. Working processes of the internal combustion engines and their systems were studied. The most important systems of the combined thermal power plants with internal combustion engines, such as fuel supply, air supply, gas distribution, cooling, lubrication, purification and exhaust gas recirculation systems were considered. The need was also noted for comprehensive optimization of the engine parameters and its main systems
{"title":"Trends in Improving Automatic Control and Regulation Systems of the Thermal Power Plants","authors":"Vladyslav Markov","doi":"10.18698/0236-3941-2023-1-97-126","DOIUrl":"https://doi.org/10.18698/0236-3941-2023-1-97-126","url":null,"abstract":"Relevance of the article is determined by the need to improve power and dynamic performance of the thermal power plants and indicators of their fuel efficiency and toxicity of the exhaust gases. An integral part of these facilities are the automatic control and regulation systems that ensure coordination of the elements and systems of the combined thermal and power facilities in a wide range of their operating modes. The most important criteria in such elements and systems coordination are the indicators characterizing toxicity of the exhaust gases. Currently, thermal power plants based on the piston and combined internal combustion engines are widely used. Main areas of improving thermal power plants with the internal combustion engines and their automatic control and regulation systems were analyzed. For example, expanding their functionality including the exhaust gas purification systems control and the use of thermal power plants in adaptation to operate on the alternative fuels; improving the quality of control and regulation processes and minimizing the share of unsteady operating modes of the thermal power plants. Current level of systems for automatic control and regulation of the thermal power plants was evaluated. Working processes of the internal combustion engines and their systems were studied. The most important systems of the combined thermal power plants with internal combustion engines, such as fuel supply, air supply, gas distribution, cooling, lubrication, purification and exhaust gas recirculation systems were considered. The need was also noted for comprehensive optimization of the engine parameters and its main systems","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74842814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18698/0236-3941-2023-1-80-96
V. Kurguzov, N. S. Astapov
The paper considers a rectangular plate with the edge crack of mode I of normal separation from the elastoplastic material with the ultimate strain. This class of materials includes, for example, the low-alloy steels used in structures operating at temperatures below the cold brittleness threshold. The strength of the plate was studied within the framework of the Neuber --- Novozhilov approach. The crack propagation criterion was formulated using the modified Leonov --- Panasyuk --- Dugdale model using an additional parameter, i.e., the plasticity zone diameter (pre-fracture zone width). Under conditions of small-scale yielding in the presence of the stress field singular feature in the vicinity of the crack tip, the two-parameter (dual) criterion for quasi-brittle fracture was formulated for mode I cracks in the elastoplastic material. The fracture dual criterion included deformation criterion at the crack tip, as well as the force criterion at the fictitious crack tip. The lengths of the original and fictitious cracks were differing by the length of the pre-fracture zone. Diagrams of the plate quasi-brittle fracture under conditions of plane deformation and plane stress were constructed. The parameters included in the proposed quasi-brittle fracture model were analyzed. It was proposed to select model parameters according to the approximation (σ--ε)-diagram of uniaxial tension and the KIc critical stress intensity factor
{"title":"Analytical Model of Quasi-Brittle Fracture of a Plate with Crack","authors":"V. Kurguzov, N. S. Astapov","doi":"10.18698/0236-3941-2023-1-80-96","DOIUrl":"https://doi.org/10.18698/0236-3941-2023-1-80-96","url":null,"abstract":"The paper considers a rectangular plate with the edge crack of mode I of normal separation from the elastoplastic material with the ultimate strain. This class of materials includes, for example, the low-alloy steels used in structures operating at temperatures below the cold brittleness threshold. The strength of the plate was studied within the framework of the Neuber --- Novozhilov approach. The crack propagation criterion was formulated using the modified Leonov --- Panasyuk --- Dugdale model using an additional parameter, i.e., the plasticity zone diameter (pre-fracture zone width). Under conditions of small-scale yielding in the presence of the stress field singular feature in the vicinity of the crack tip, the two-parameter (dual) criterion for quasi-brittle fracture was formulated for mode I cracks in the elastoplastic material. The fracture dual criterion included deformation criterion at the crack tip, as well as the force criterion at the fictitious crack tip. The lengths of the original and fictitious cracks were differing by the length of the pre-fracture zone. Diagrams of the plate quasi-brittle fracture under conditions of plane deformation and plane stress were constructed. The parameters included in the proposed quasi-brittle fracture model were analyzed. It was proposed to select model parameters according to the approximation (σ--ε)-diagram of uniaxial tension and the KIc critical stress intensity factor","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"105 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79234636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18698/0236-3933-2023-1-60-82
G.I. Kulagin
Currently, one of the promising areas in the development of network technologies is the wireless self-organizing networks based on the unmanned aerial vehicles, i.e., FANET (Flying Ad-Hoc Networks), which most important task in the course of their operation lies in organizing the effective data exchange. The distinctive properties of wireless self-organizing networks with altering topology are leading to the fact that technical solutions and methods of determination of the data delivery routes used in telecommunication networks with the traditional fixed architecture turn out to be inefficient in the special FANET networks and are not able to provide the required performance. At the same time, wireless self-organizing networks based on the unmanned aerial vehicles possess their own techniques used in data routing, which are subject to the requirements that take into account characteristic differences inherent in the networks of this type, including high mobility and low density of the nodes, dynamic and frequent topology alterations. Features and methods for determining data delivery routes were analyzed in the wireless self-organizing networks, which basis (nodes) were the unmanned aerial vehicles
{"title":"Analysis of Features and Methods for Data Delivery Routes Determination in the Wireless Self-Organizing Networks Based on the Unmanned Aerial Vehicles","authors":"G.I. Kulagin","doi":"10.18698/0236-3933-2023-1-60-82","DOIUrl":"https://doi.org/10.18698/0236-3933-2023-1-60-82","url":null,"abstract":"Currently, one of the promising areas in the development of network technologies is the wireless self-organizing networks based on the unmanned aerial vehicles, i.e., FANET (Flying Ad-Hoc Networks), which most important task in the course of their operation lies in organizing the effective data exchange. The distinctive properties of wireless self-organizing networks with altering topology are leading to the fact that technical solutions and methods of determination of the data delivery routes used in telecommunication networks with the traditional fixed architecture turn out to be inefficient in the special FANET networks and are not able to provide the required performance. At the same time, wireless self-organizing networks based on the unmanned aerial vehicles possess their own techniques used in data routing, which are subject to the requirements that take into account characteristic differences inherent in the networks of this type, including high mobility and low density of the nodes, dynamic and frequent topology alterations. Features and methods for determining data delivery routes were analyzed in the wireless self-organizing networks, which basis (nodes) were the unmanned aerial vehicles","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75304367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18698/0236-3933-2023-1-15-31
S. V. Gavrish, D.N. Kugushev, R.M. Ushakov
The paper presents main results of investigating electrical parameters and characteristics of the pulsed xenon lamp ultraviolet radiation with a U-shaped plasma channel and caprod current leads. The gas-discharge lamp design feature suggests presence of the ballast transelectrode volumes contributing to the xenon escape from the discharge and the radiation acting from one part of the U-shaped plasma channel on the other. Literature sources devoted to the specified phenomena were analyzed. Factors influencing the xenon plasma thermophysical state were established. Due to the lack of techniques for registering the pulsed radiation in a narrow spectral range of 200--300 nm, measurement techniques and investigation hardware were considered in detail. The time interval for establishing the gas-dynamic equilibrium in a pulsed xenon lamp in the process of its entry into the nominal operating mode was determined by calculation and experiment. Studies of the Vt transelectrode volume effect on characteristics of the pulsed xenon plasma were carried out in the range of 0.16 < Vt /Vi < 0.3. It was established that the possible factors leading to a decrease in the current density and intensity of the UV radiation included the modes of electrical supply and evaporation of the quartz shell limiting the discharge. It was shown that self-radiation return in plasma contributed to an increase in the current density of the pulsed xenon lamp
{"title":"Investigation of Characteristics of the U-Shaped Plasma Channel of the Pulsed Xenon Lamps","authors":"S. V. Gavrish, D.N. Kugushev, R.M. Ushakov","doi":"10.18698/0236-3933-2023-1-15-31","DOIUrl":"https://doi.org/10.18698/0236-3933-2023-1-15-31","url":null,"abstract":"The paper presents main results of investigating electrical parameters and characteristics of the pulsed xenon lamp ultraviolet radiation with a U-shaped plasma channel and caprod current leads. The gas-discharge lamp design feature suggests presence of the ballast transelectrode volumes contributing to the xenon escape from the discharge and the radiation acting from one part of the U-shaped plasma channel on the other. Literature sources devoted to the specified phenomena were analyzed. Factors influencing the xenon plasma thermophysical state were established. Due to the lack of techniques for registering the pulsed radiation in a narrow spectral range of 200--300 nm, measurement techniques and investigation hardware were considered in detail. The time interval for establishing the gas-dynamic equilibrium in a pulsed xenon lamp in the process of its entry into the nominal operating mode was determined by calculation and experiment. Studies of the Vt transelectrode volume effect on characteristics of the pulsed xenon plasma were carried out in the range of 0.16 < Vt /Vi < 0.3. It was established that the possible factors leading to a decrease in the current density and intensity of the UV radiation included the modes of electrical supply and evaporation of the quartz shell limiting the discharge. It was shown that self-radiation return in plasma contributed to an increase in the current density of the pulsed xenon lamp","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85518010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18698/0236-3941-2023-1-4-21
M.V. Biryukova, A. Tufan, V. Ermakov
Flawless spacecraft operation and successful implementtation of their research in orbit mainly depend on technical and operational characteristics of the spacecraft orientation and stabilization control systems in space relative to the base frame of reference axes achieved through stabilizing properties of certain external and internal perturbations. The research was aimed at determining static and dynamic imbalances and analyzed the levels of influence of forces and moments created by non-contact electric motor-flywheel operating at the various rotor speeds. In order to reduce the static and dynamic imbalance of the non-contact electric motor-flywheel obtained as a result of ongoing experimental studies, it was proposed to introduce a vibration isolator with natural frequency significantly lower than that in the conventional systems in order to statically hold the non-contact electric motor-flywheel during ground and flight operation. The vibration isolator should have small mass and rigidity, as well as a wide range of operating temperatures, etc. Depending on the orbit altitude, the moments of external disturbing forces acting on the Iskra-5 spacecraft were determined. Electric DC motor-flywheels of various types were analyzed. It was shown that introduction of the non-contact electric motor-flywheel as the executive element of the orientation and stabilization control systems on small spacecraft improved the orientation accuracy. Ways to reduce the effect of vibration disturbances on the spacecraft structure from the non-contact electric motor-flywheel were considered
{"title":"Approach to Reducing Vibroactivity of Small Spacecraft","authors":"M.V. Biryukova, A. Tufan, V. Ermakov","doi":"10.18698/0236-3941-2023-1-4-21","DOIUrl":"https://doi.org/10.18698/0236-3941-2023-1-4-21","url":null,"abstract":"Flawless spacecraft operation and successful implementtation of their research in orbit mainly depend on technical and operational characteristics of the spacecraft orientation and stabilization control systems in space relative to the base frame of reference axes achieved through stabilizing properties of certain external and internal perturbations. The research was aimed at determining static and dynamic imbalances and analyzed the levels of influence of forces and moments created by non-contact electric motor-flywheel operating at the various rotor speeds. In order to reduce the static and dynamic imbalance of the non-contact electric motor-flywheel obtained as a result of ongoing experimental studies, it was proposed to introduce a vibration isolator with natural frequency significantly lower than that in the conventional systems in order to statically hold the non-contact electric motor-flywheel during ground and flight operation. The vibration isolator should have small mass and rigidity, as well as a wide range of operating temperatures, etc. Depending on the orbit altitude, the moments of external disturbing forces acting on the Iskra-5 spacecraft were determined. Electric DC motor-flywheels of various types were analyzed. It was shown that introduction of the non-contact electric motor-flywheel as the executive element of the orientation and stabilization control systems on small spacecraft improved the orientation accuracy. Ways to reduce the effect of vibration disturbances on the spacecraft structure from the non-contact electric motor-flywheel were considered","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85017183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18698/0236-3933-2023-1-44-59
A. Diveev
The present article considers the problem of numerical solution of the terminal optimal control problem. The general statement of the terminal optimal control problem and a brief overview of its solving methods are presented. With a direct approach and reduction of the optimal control problem to the finite-dimensional optimization problem, the target functional on the space of desired parameters, regardless of the type of approximation of the control function, may not have the unimodal property. Therefore, it is advisable to use evolutionary algorithms to solve the problem. A general approach to solving the terminal optimal control problem of evolutionary computational algorithms is presented. The paper presents a description of some evolutionary algorithms that were selected as the most effective for solving the optimal control problem. A hybrid evolutionary algorithm based on a combination of several evolutionary algorithms is considered. The computational experiment considers the terminal optimal control problems, for which optimal solutions were found by known classical numerical methods that use the gradient of the target functionality when searching. Comparison of the results obtained by classical and evolutionary methods by functional values and computational costs allows us to conclude that evolutionary algorithms are able to effectively solve the terminal optimal control problems
{"title":"Evolutionary Сomputation for Solving the Terminal Optimal Control Problem","authors":"A. Diveev","doi":"10.18698/0236-3933-2023-1-44-59","DOIUrl":"https://doi.org/10.18698/0236-3933-2023-1-44-59","url":null,"abstract":"The present article considers the problem of numerical solution of the terminal optimal control problem. The general statement of the terminal optimal control problem and a brief overview of its solving methods are presented. With a direct approach and reduction of the optimal control problem to the finite-dimensional optimization problem, the target functional on the space of desired parameters, regardless of the type of approximation of the control function, may not have the unimodal property. Therefore, it is advisable to use evolutionary algorithms to solve the problem. A general approach to solving the terminal optimal control problem of evolutionary computational algorithms is presented. The paper presents a description of some evolutionary algorithms that were selected as the most effective for solving the optimal control problem. A hybrid evolutionary algorithm based on a combination of several evolutionary algorithms is considered. The computational experiment considers the terminal optimal control problems, for which optimal solutions were found by known classical numerical methods that use the gradient of the target functionality when searching. Comparison of the results obtained by classical and evolutionary methods by functional values and computational costs allows us to conclude that evolutionary algorithms are able to effectively solve the terminal optimal control problems","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75380973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18698/0236-3933-2023-1-32-43
A. Sokolov, A. Akentyev, Y.I. Merenkova, A. A. Fokina
The paper presents experimental research of the diffraction patterns of radiation reflected from the retroreflector spherical system of glass geodesic passive satellites of the Blitz-type created at the JSC "SPC "PSI". The Blitz-type satellites are used in the interests of the GLONASS for high-precision laser ranging and are a set of concentric layers with different refractive indices. The purpose of the study was to determine based on the experiment data the effective beam diameter forming the reflected radiation diffraction pattern in the far zone, which value was required to calculate the satellite energy parameter, i.e., the effective scattering surface. The effective beam diameter dimension for the indicated retroreflector spherical system was determined experimentally by installing various diaphragms that limited the radiation beam size. It is shown that alterations in the diffraction pattern in the far field started, when the diaphragm opening was smaller than the effective diameter. Experimental and calculated values of the satellite’s equivalent scattering surface were comparatively analyzed. According to the experimental results, the diffraction pattern is determined by the central zone of the retroreflector spherical system, where wave aberrations are less than a certain limit corresponding to the Fresnel diffraction with several active first zones
{"title":"Experimental Research of the Diffraction Pattern of Radiation Reflected from the Retroreflector Spherical Glass Satellite","authors":"A. Sokolov, A. Akentyev, Y.I. Merenkova, A. A. Fokina","doi":"10.18698/0236-3933-2023-1-32-43","DOIUrl":"https://doi.org/10.18698/0236-3933-2023-1-32-43","url":null,"abstract":"The paper presents experimental research of the diffraction patterns of radiation reflected from the retroreflector spherical system of glass geodesic passive satellites of the Blitz-type created at the JSC \"SPC \"PSI\". The Blitz-type satellites are used in the interests of the GLONASS for high-precision laser ranging and are a set of concentric layers with different refractive indices. The purpose of the study was to determine based on the experiment data the effective beam diameter forming the reflected radiation diffraction pattern in the far zone, which value was required to calculate the satellite energy parameter, i.e., the effective scattering surface. The effective beam diameter dimension for the indicated retroreflector spherical system was determined experimentally by installing various diaphragms that limited the radiation beam size. It is shown that alterations in the diffraction pattern in the far field started, when the diaphragm opening was smaller than the effective diameter. Experimental and calculated values of the satellite’s equivalent scattering surface were comparatively analyzed. According to the experimental results, the diffraction pattern is determined by the central zone of the retroreflector spherical system, where wave aberrations are less than a certain limit corresponding to the Fresnel diffraction with several active first zones","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74504257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.18698/1812-3368-2023-1-23-44
Y. Chashechkin
The paper studies acoustic signals in two modes of merging with water in a freely falling water droplet by the matched optical and acoustic methods. Only the primary sound packet was observed in the intrusive mode at the low drop speed, when the cavity was formed with a delay in the colored wake of the inflowing liquid. Experiments demonstrated the drop speed influence on the primary signal parameters. At the high droplet speed, the cavity started to form from the moment of the initial contact. The flow pattern became more complicated, the droplet substance was distributed over the emerged cavity surface and the grown crown in the form of separate fibers forming the line and mesh structures. The falling section of the primary acoustic signal was formed by a group of pulses with the complex spectral composition. Further, one or more low-frequency sound packets were registered after the pause. Spectral portrait of the secondary packets was related to the shape of the detached gas cavity. Smooth axisymmetric cavity was radiating the monochromatic packet. The complex-shaped cavity was transforming into a gas bubble and emitting the multi-frequency signal. Duration and amplitude of the secondary sound signals were depending on the transformation rate of the separated gas cavity into a smooth spheroidal bubble. The acoustic signal parameters were changing nonmonotonically with increasing velocity of the merging drop
{"title":"Acoustics and Hydrodynamics of the Drop Impact: Two Modes of Sound Packets Emission","authors":"Y. Chashechkin","doi":"10.18698/1812-3368-2023-1-23-44","DOIUrl":"https://doi.org/10.18698/1812-3368-2023-1-23-44","url":null,"abstract":"The paper studies acoustic signals in two modes of merging with water in a freely falling water droplet by the matched optical and acoustic methods. Only the primary sound packet was observed in the intrusive mode at the low drop speed, when the cavity was formed with a delay in the colored wake of the inflowing liquid. Experiments demonstrated the drop speed influence on the primary signal parameters. At the high droplet speed, the cavity started to form from the moment of the initial contact. The flow pattern became more complicated, the droplet substance was distributed over the emerged cavity surface and the grown crown in the form of separate fibers forming the line and mesh structures. The falling section of the primary acoustic signal was formed by a group of pulses with the complex spectral composition. Further, one or more low-frequency sound packets were registered after the pause. Spectral portrait of the secondary packets was related to the shape of the detached gas cavity. Smooth axisymmetric cavity was radiating the monochromatic packet. The complex-shaped cavity was transforming into a gas bubble and emitting the multi-frequency signal. Duration and amplitude of the secondary sound signals were depending on the transformation rate of the separated gas cavity into a smooth spheroidal bubble. The acoustic signal parameters were changing nonmonotonically with increasing velocity of the merging drop","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84074971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.18698/1812-3368-2023-1-82-94
B. Vintaikin, A. Smirnov, S. Shevchenko, A. A. Drenin, V. I. Sheykina
Methods of the X-ray phase analysis, as well as optical and scanning electron microscopy supplemented by construction of the distribution maps for such chemical elements as oxygen and copper demonstrated presence in the structure of the PR-BrX brand powder made of bronze with the FСС lattice of oxygen-containing phases, i.e., copper oxides (CuO, Cu2O) located along the grain boundaries and on the powder particle surface. Using these methods demonstrated that annealing in the ammonia at a temperature of 450 °C promoted reduction of the oxide phases to the single-phase structure of the initial solid solution. It was found out that the presence of oxides on the powder particles surface and grain boundaries inside these particles made the oxidized powder unsuitable for use in the selective laser melting technology. This is due to reduction of the oxides, and, consequently, to the outgassing and excessive porosity of objects during the laser 3D printing. It was proved that reductive annealing in ammonia formed a single-phase structure of powder particles based on the FCC copper, which made it possible to grow objects with small porosity not exceeding 2.5 % using various laser processing modes
{"title":"Phase Composition and Structure of the BrX Chromium Bronze Powder","authors":"B. Vintaikin, A. Smirnov, S. Shevchenko, A. A. Drenin, V. I. Sheykina","doi":"10.18698/1812-3368-2023-1-82-94","DOIUrl":"https://doi.org/10.18698/1812-3368-2023-1-82-94","url":null,"abstract":"Methods of the X-ray phase analysis, as well as optical and scanning electron microscopy supplemented by construction of the distribution maps for such chemical elements as oxygen and copper demonstrated presence in the structure of the PR-BrX brand powder made of bronze with the FСС lattice of oxygen-containing phases, i.e., copper oxides (CuO, Cu2O) located along the grain boundaries and on the powder particle surface. Using these methods demonstrated that annealing in the ammonia at a temperature of 450 °C promoted reduction of the oxide phases to the single-phase structure of the initial solid solution. It was found out that the presence of oxides on the powder particles surface and grain boundaries inside these particles made the oxidized powder unsuitable for use in the selective laser melting technology. This is due to reduction of the oxides, and, consequently, to the outgassing and excessive porosity of objects during the laser 3D printing. It was proved that reductive annealing in ammonia formed a single-phase structure of powder particles based on the FCC copper, which made it possible to grow objects with small porosity not exceeding 2.5 % using various laser processing modes","PeriodicalId":12961,"journal":{"name":"Herald of the Bauman Moscow State Technical University. Series Natural Sciences","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87594127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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