Zeitschriften und Ausgaben

Volumen 59 (2022): Heft 5 (October 2022)

Volumen 59 (2022): Heft 4 (August 2022)

Volumen 59 (2022): Heft 3 (June 2022)

Volumen 59 (2022): Heft s3 (June 2022)

Volumen 59 (2022): Heft 2 (April 2022)

Volumen 59 (2022): Heft 1 (February 2022)

Volumen 58 (2021): Heft 6 (December 2021)

Volumen 58 (2021): Heft 5 (October 2021)

Volumen 58 (2021): Heft 4 (August 2021)

Volumen 58 (2021): Heft 3 (June 2021)

Volumen 58 (2021): Heft 2 (April 2021)

Volumen 58 (2021): Heft 1 (February 2021)

Volumen 57 (2020): Heft 6 (December 2020)

Volumen 57 (2020): Heft 5 (October 2020)

Volumen 57 (2020): Heft 4 (August 2020)

Volumen 57 (2020): Heft 3 (June 2020)

Volumen 57 (2020): Heft 1-2 (April 2020)

Volumen 56 (2019): Heft 6 (December 2019)

Volumen 56 (2019): Heft 5 (October 2019)

Volumen 56 (2019): Heft 4 (August 2019)

Volumen 56 (2019): Heft 3 (June 2019)

Volumen 56 (2019): Heft 2 (April 2019)

Volumen 56 (2019): Heft 1 (February 2019)

Volumen 55 (2018): Heft 6 (December 2018)

Volumen 55 (2018): Heft 5 (October 2018)

Volumen 55 (2018): Heft 4 (August 2018)

Volumen 55 (2018): Heft 3 (June 2018)

Volumen 55 (2018): Heft 2 (April 2018)

Volumen 55 (2018): Heft 1 (February 2018)

Volumen 54 (2017): Heft 6 (December 2017)

Volumen 54 (2017): Heft 5 (October 2017)

Volumen 54 (2017): Heft 4 (August 2017)

Volumen 54 (2017): Heft 3 (June 2017)

Volumen 54 (2017): Heft 2 (April 2017)

Volumen 54 (2017): Heft 1 (February 2017)

Volumen 53 (2016): Heft 6 (December 2016)

Volumen 53 (2016): Heft 5 (October 2016)

Volumen 53 (2016): Heft 4 (August 2016)

Volumen 53 (2016): Heft 3 (June 2016)

Volumen 53 (2016): Heft 2 (April 2016)

Volumen 53 (2016): Heft 1 (February 2016)

Volumen 52 (2015): Heft 6 (December 2015)

Volumen 52 (2015): Heft 5 (October 2015)

Volumen 52 (2015): Heft 4 (August 2015)

Volumen 52 (2015): Heft 3 (June 2015)

Volumen 52 (2015): Heft 2 (April 2015)

Volumen 52 (2015): Heft 1 (February 2015)

Volumen 51 (2014): Heft 6 (December 2014)

Volumen 51 (2014): Heft 5 (October 2014)

Volumen 51 (2014): Heft 4 (August 2014)

Volumen 51 (2014): Heft 3 (June 2014)

Volumen 51 (2014): Heft 2 (April 2014)

Volumen 51 (2014): Heft 1 (February 2014)

Volumen 50 (2013): Heft 6 (December 2013)

Volumen 50 (2013): Heft 5 (October 2013)

Volumen 50 (2013): Heft 4 (August 2013)

Volumen 50 (2013): Heft 3 (June 2013)

Volumen 50 (2013): Heft 2 (April 2013)

Volumen 50 (2013): Heft 1 (February 2013)

Volumen 49 (2012): Heft 6-II (December 2012)

Volumen 49 (2012): Heft 6-I (December 2012)

Volumen 49 (2012): Heft 5 (October 2012)

Volumen 49 (2012): Heft 4 (August 2012)

Volumen 49 (2012): Heft 2 (April 2012)

Volumen 49 (2012): Heft 1 (February 2012)

Volumen 48 (2011): Heft 6 (December 2011)

Volumen 48 (2011): Heft 5 (October 2011)

Volumen 48 (2011): Heft 4 (August 2011)

Volumen 48 (2011): Heft 3 (June 2011)

Volumen 48 (2011): Heft 2 (April 2011)

Volumen 48 (2011): Heft 1 (February 2011)

Volumen 47 (2010): Heft 6 (December 2010)

Volumen 47 (2010): Heft 5 (October 2010)

Volumen 47 (2010): Heft 4 (August 2010)

Volumen 47 (2010): Heft 3 (June 2010)

Volumen 47 (2010): Heft 2 (April 2010)

Volumen 47 (2010): Heft 1 (February 2010)

Volumen 46 (2009): Heft 6 (December 2009)

Volumen 46 (2009): Heft 5 (October 2009)

Volumen 46 (2009): Heft 4 (August 2009)

Volumen 46 (2009): Heft 3 (June 2009)

Volumen 46 (2009): Heft 2 (April 2009)

Volumen 46 (2009): Heft 1 (February 2009)

Volumen 45 (2008): Heft 6 (December 2008)

Volumen 45 (2008): Heft 5 (October 2008)

Volumen 45 (2008): Heft 4 (August 2008)

Volumen 45 (2008): Heft 3 (June 2008)

Volumen 45 (2008): Heft 2 (April 2008)

Volumen 45 (2008): Heft 1 (February 2008)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2255-8896
Erstveröffentlichung
18 Mar 2008
Erscheinungsweise
6 Hefte pro Jahr
Sprachen
Englisch

Suche

Volumen 59 (2022): Heft s3 (June 2022)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2255-8896
Erstveröffentlichung
18 Mar 2008
Erscheinungsweise
6 Hefte pro Jahr
Sprachen
Englisch

Suche

10 Artikel
Uneingeschränkter Zugang

Microwave Observations of the Sun with Virac RT-32 Radio Telescope: The Expansion of Possibilities

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 5 - 13

Zusammenfassung

Abstract

Nowadays there is increasing interest in narrowing coronal areas with reduced brightness temperatures (LTR – Low Temperature Regions) associated with local open magnetic fields (S-web, “coronal partings”, “dark coronal corridors”) as one of the eventual sources of slow solar wind. Ventspils International Radio Astronomy Centre (VIRAC) performs routine spectral polarimetric observations of the Sun with RT-32 radio telescope equipped with the multi-channel (16 frequency channels) spectral polarimeter for the wave length range of 3.2–4.7 cm (6.3–9.3 GHz) and both circular polarizations simultaneously. The analysis of relevant tasks of clear and reliable observations and detections of LTR shows the necessity to improve noise parameters, dynamic range and stability of the actual solar spectral polarimeter and to expand its wavelength range. Taking into account these requirements, the low noise and thermally stabilized solar spectral polarimeter was developed. The new multi-channel spectral polarimeter is expected to observe right and left circular polarization of the solar emission in the wavelength range of 2.1–7.5 cm (4.1–14.3 GHz) divided into 12 frequency bands. The dynamic range was expanded to >36 db and the signal/noise ratio (referred to as quiet Sun brightness temperatures) was enhanced to > 22–24 db.

The paper deals with some test observations of the newly developed solar spectral polar-imeter and its feature analysis. Some eventual problems of solar physics which could be solved with the spectral polarimeter are also discussed.

Schlüsselwörter

  • Radio astronomy
  • slow solar wind
  • solar physics
  • spectral polarimeter
Uneingeschränkter Zugang

Observations of Weak Galactic OH Masers in 1.6 GHz Frequency Band Using Irbene RT-32 Radio Telescope

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 14 - 22

Zusammenfassung

Abstract

Ventspils International Radio Astronomy Centre (Ventspils University of Applied Sciences) is implementing the scientific project “Complex Investigations of the Small Bodies in the Solar System” (lzp-2018/1-0401) related to the research of the small bodies in the Solar system (mainly, focusing on asteroids and comets) using methods of radio astronomy and signal processing. One of the research activities is weak hydroxyl (OH) radical observation in the radio range – single antenna observations using Irbene RT-32 radio telescope. To detect weak (0.1 Jy) OH masers of astronomical objects using radio methods, a research group in Ventspils adapted the Irbene RT-32 radio telescope working at 1665.402 and 1667.359 MHz frequencies. Spectral analysis using Fourier transform and continuous wavelet transform was applied to radio astronomical data from multiple observations related to weak OH maser detection. Multiple observation sessions of OH maser objects (R LMi, RU Ari, V524 Cas, OH 138.0+7.2, U Aur, etc) were carried out in 2020–2021.

Schlüsselwörter

  • Data processing
  • radio telescopes
  • weak OH masers
Uneingeschränkter Zugang

Radar Observations of Old Centaur Rocket from 1966

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 23 - 29

Zusammenfassung

Abstract

We report the results of radar observations of a near-Earth object discovered on 17 September 2020, with the Pan-STARRS 1 telescope at the Haleakala Observatory in Hawaii. Initially, this object was considered an asteroid and even received the standard provisional designation 2020 SO by the Minor Planet Center. However, its Earth-like orbit and low relative velocity suggested that the object may be of artificial origin, being the Centaur rocket booster from the Surveyor 2 mission that was launched to the Moon on 20 September 1966. In the period from November 2020 to March 2021, this object approached the Earth twice within one lunar distance of the Earth. Radar observations were conducted on 30 November in bistatic mode with the 70-m Goldstone Solar System Radar DSS-14 and 32-m radio telescope RT-32 at the Svetloe Observatory, while the object was in the visibility window of two antennas at about 200 thousand km from the Earth. The main goal of the study was to determine the physical properties of this object using radar astronomy to clarify its origin.

Schlüsselwörter

  • Near-Earth objects
  • radar observations
  • spacecraft
  • space debris
Uneingeschränkter Zugang

Importance of Spectrum Management in Radio Astronomy

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 30 - 38

Zusammenfassung

Abstract

The increasing terrestrial and space-borne communications are causing major problems to the radio astronomy observations. Only a minor part of the frequencies is allocated to the passive services, such as Radio Astronomy Services (RAS). There are only a few, relatively narrow frequency bands below 20 GHz, which are still suitable for the radio astronomical observations. In addition, Out-of-Band (OoB) emissions will be a real threat to the observations on these bands. On behalf of all European radio astronomers, the Committee on Radio Astronomy Frequencies (CRAF) of the European Science Foundation (ESF) coordinates activities to keep the frequency bands used by radio astronomy and space sciences free of interference. Along with interference caused by active radio communication services, the local electronic device selection should be considered in the observatories. For instance, more common LED based lamps could cause harmful interference for the observations. Thus, it is very important to perform continuous radio frequency interference (RFI) monitoring locally, in each radio observatory.

Schlüsselwörter

  • Frequency allocation
  • radio astronomy
  • radio frequency interference (RFI)
  • spectrum management
Uneingeschränkter Zugang

Relationship Between Solar Millimeter and Soft X-Ray Emissions

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 39 - 47

Zusammenfassung

Abstract

The connection between solar radio and soft X-ray emission has earlier been studied at various radio frequencies. For instance, the intensity peak times during solar flares have been compared between these two wavelength regimes. It has been reported that solar radio emission peaks before soft X-ray emission during a flare. However, opposite results have also been presented. In this study, we compare millimetre (8 mm) solar and soft X-ray emissions (0.5–4 Å and 1–8 Å). The radio observations were made at Metsähovi Radio Observatory of Aalto University in Finland between 2015 and 2019. The soft X-ray data were observed with GOES-15 (Geostationary Operational Environmental Satellite). The data show that the solar millimetre emission can peak either before or after soft X-ray peak emission. In this study, we present two different scenarios, which could explain the peaking time differences and behaviour. The first scenario proposes a tight connection between the millimetre (8 mm) and soft X-ray emissions, the second one is for cases where the emission mechanisms are more separate.

Schlüsselwörter

  • Chromosphere
  • corona
  • instrumentation and data management
  • radio bursts
  • radio emission
Uneingeschränkter Zugang

Magnetic Flux Switching Type Permanent Magnet Generator for Bicycles: Modelling and an Experimental Study

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 48 - 57

Zusammenfassung

Abstract

The article introduces two new designs of flux switching permanent magnet alternators with a radial and an axial arrangement of the inductor relative to the magnetic flux switch. The study presents the results of 3D magnetic flux modelling along with the outcomes of physical experiments. In the course of laboratory experiments, the results of theoretical estimations are compared with actual physical performance parameters. The results are presented in the form of power and output voltage curves in relation to the frequency and load current. The study proposes the practical application of the alternators based on the magnetic flux switching principle in the development of a bicycle generator. Laboratory test models are made of a laminated steel using a waste-free technology.

Schlüsselwörter

  • Bicycles
  • magnetic fields
  • modelling
  • permanent magnet machines
Uneingeschränkter Zugang

Axial Flux Switching Permanent Magnet Alternator with External Magnetic Cores

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 58 - 68

Zusammenfassung

Abstract

The article introduces the results of studying the magnetic field distribution in the alternator inductor with an axial arrangement of open magnetic cores (OMC) and external closure of magnetic fluxes. The study compares the efficiency of using magnetic fluxes from permanent magnets (PM) on the example of two model variants of inductors with OMC developed by the authors. The analysis of the density distribution of magnetic fluxes in OMC was carried out by 3D modelling of the magnetic field using EMWorks software. It has been shown that such generators can be manufactured using a waste-free technology for strip of OMC. This technology significantly reduces the production costs of OMC. By modelling the distribution of magnetic fluxes in the OMC of the inductor, the results of experimental studies and analysis of the created device show that the capacity of generator can be varied by changing its dimensions and the number of the toggle switches on the rotor. This allows the alternator to be adapted to the load requirements – power banks and bicycle electronics.

Schlüsselwörter

  • Bicycles
  • magnetic fields
  • modelling
  • permanent magnet machines
Uneingeschränkter Zugang

The Study of Properties of an Axial Flux Switching Permanent Magnet Alternator with Open Magnetic Cores

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 69 - 81

Zusammenfassung

Abstract

The article studies magnetic field distribution in the alternator inductors with an axial arrangement of open magnetic cores (OMC) and an external closure of the magnetic flux. The study compares the efficiency of magnetic flux utilization for four models with different modifications of the geometry of the magnetic circuit of inductors. The analysis of the density distribution of magnetic flux in OMC is carried out by 3D modelling of the magnetic field using EMWorks software. Based on the experimental study of the properties of the base model, the influence of the configuration of the magnetic circuit of the inductor on the efficiency of the alternator is shown. The results are presented in the form of tables and diagrams characterising changes in magnetic fluxes and electromotive force (EMF) in relative units. The results provide the grounds for assessing the potential and possible limits of optimization with respect to the size of air gaps and dimensions of the magnetic flux toggle switches. The study indicates that the proposed alternator can be adapted for various load requirements and optimized for various applications, such as charging power banks and powering bicycle electronics. The study also demonstrates that for such generators, OMC can be manufactured using a waste-free strip production technology.

Schlüsselwörter

  • Bicycle electronics
  • magnetic field distribution
  • modelling of magnetic fields
  • permanent magnet machines
Uneingeschränkter Zugang

Artificial Intelligence Meets Radio Astronomy

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 82 - 95

Zusammenfassung

Abstract

Artificial intelligence is widely spreading in all modern technologies. Such a very powerful methodology can have important applications in radio astronomy technology, for instance, in the new DBBC4 VLBI backend development project and in the low frequency array AntArr under development on the Etna slopes in Italy.

In the present paper, we describe the method currently adopted for those projects and some possible applications, which could provide substantial new features in this decade to the radio astronomy science and technology.

Schlüsselwörter

  • Artificial intelligence
  • DBBC
  • radio astronomy
  • radio interference
Uneingeschränkter Zugang

Hydrogen Hydraulic Compression System for Refuelling Stations

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 96 - 105

Zusammenfassung

Abstract

The article investigates the properties and potential of compressed hydrogen as one of the most promising energy carriers in order to facilitate the development of energy storage capabilities and lay down a stable foundation for the future of a sustainable energy sector. The study considers the use of hydrogen, compressed at high pressure from 50 MPa to 100 MPa, at refuelling stations to supply electric cars. The technical properties of modern hydraulic compressors used for hydrogen accumulation in high pressure buffer containers are considered. The study shows that the design of hydraulic compressors in terms of their technical characteristics optimally corresponds to the primary requirements for their use as booster compressors at refuelling stations. The authors conclude with the proposal of an enhanced design of the hydraulic compressor with the use of fluid flow counters in a control system of a hydrogen compression cycle. The proposed technical solution provides for continuous monitoring of the hydrogen compression process that increases the reliability of control system operation.

Schlüsselwörter

  • Energy storage
  • fluid flow counters
  • hydrogen
  • high pressure
  • hydraulic compressors
  • refuelling stations
10 Artikel
Uneingeschränkter Zugang

Microwave Observations of the Sun with Virac RT-32 Radio Telescope: The Expansion of Possibilities

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 5 - 13

Zusammenfassung

Abstract

Nowadays there is increasing interest in narrowing coronal areas with reduced brightness temperatures (LTR – Low Temperature Regions) associated with local open magnetic fields (S-web, “coronal partings”, “dark coronal corridors”) as one of the eventual sources of slow solar wind. Ventspils International Radio Astronomy Centre (VIRAC) performs routine spectral polarimetric observations of the Sun with RT-32 radio telescope equipped with the multi-channel (16 frequency channels) spectral polarimeter for the wave length range of 3.2–4.7 cm (6.3–9.3 GHz) and both circular polarizations simultaneously. The analysis of relevant tasks of clear and reliable observations and detections of LTR shows the necessity to improve noise parameters, dynamic range and stability of the actual solar spectral polarimeter and to expand its wavelength range. Taking into account these requirements, the low noise and thermally stabilized solar spectral polarimeter was developed. The new multi-channel spectral polarimeter is expected to observe right and left circular polarization of the solar emission in the wavelength range of 2.1–7.5 cm (4.1–14.3 GHz) divided into 12 frequency bands. The dynamic range was expanded to >36 db and the signal/noise ratio (referred to as quiet Sun brightness temperatures) was enhanced to > 22–24 db.

The paper deals with some test observations of the newly developed solar spectral polar-imeter and its feature analysis. Some eventual problems of solar physics which could be solved with the spectral polarimeter are also discussed.

Schlüsselwörter

  • Radio astronomy
  • slow solar wind
  • solar physics
  • spectral polarimeter
Uneingeschränkter Zugang

Observations of Weak Galactic OH Masers in 1.6 GHz Frequency Band Using Irbene RT-32 Radio Telescope

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 14 - 22

Zusammenfassung

Abstract

Ventspils International Radio Astronomy Centre (Ventspils University of Applied Sciences) is implementing the scientific project “Complex Investigations of the Small Bodies in the Solar System” (lzp-2018/1-0401) related to the research of the small bodies in the Solar system (mainly, focusing on asteroids and comets) using methods of radio astronomy and signal processing. One of the research activities is weak hydroxyl (OH) radical observation in the radio range – single antenna observations using Irbene RT-32 radio telescope. To detect weak (0.1 Jy) OH masers of astronomical objects using radio methods, a research group in Ventspils adapted the Irbene RT-32 radio telescope working at 1665.402 and 1667.359 MHz frequencies. Spectral analysis using Fourier transform and continuous wavelet transform was applied to radio astronomical data from multiple observations related to weak OH maser detection. Multiple observation sessions of OH maser objects (R LMi, RU Ari, V524 Cas, OH 138.0+7.2, U Aur, etc) were carried out in 2020–2021.

Schlüsselwörter

  • Data processing
  • radio telescopes
  • weak OH masers
Uneingeschränkter Zugang

Radar Observations of Old Centaur Rocket from 1966

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 23 - 29

Zusammenfassung

Abstract

We report the results of radar observations of a near-Earth object discovered on 17 September 2020, with the Pan-STARRS 1 telescope at the Haleakala Observatory in Hawaii. Initially, this object was considered an asteroid and even received the standard provisional designation 2020 SO by the Minor Planet Center. However, its Earth-like orbit and low relative velocity suggested that the object may be of artificial origin, being the Centaur rocket booster from the Surveyor 2 mission that was launched to the Moon on 20 September 1966. In the period from November 2020 to March 2021, this object approached the Earth twice within one lunar distance of the Earth. Radar observations were conducted on 30 November in bistatic mode with the 70-m Goldstone Solar System Radar DSS-14 and 32-m radio telescope RT-32 at the Svetloe Observatory, while the object was in the visibility window of two antennas at about 200 thousand km from the Earth. The main goal of the study was to determine the physical properties of this object using radar astronomy to clarify its origin.

Schlüsselwörter

  • Near-Earth objects
  • radar observations
  • spacecraft
  • space debris
Uneingeschränkter Zugang

Importance of Spectrum Management in Radio Astronomy

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 30 - 38

Zusammenfassung

Abstract

The increasing terrestrial and space-borne communications are causing major problems to the radio astronomy observations. Only a minor part of the frequencies is allocated to the passive services, such as Radio Astronomy Services (RAS). There are only a few, relatively narrow frequency bands below 20 GHz, which are still suitable for the radio astronomical observations. In addition, Out-of-Band (OoB) emissions will be a real threat to the observations on these bands. On behalf of all European radio astronomers, the Committee on Radio Astronomy Frequencies (CRAF) of the European Science Foundation (ESF) coordinates activities to keep the frequency bands used by radio astronomy and space sciences free of interference. Along with interference caused by active radio communication services, the local electronic device selection should be considered in the observatories. For instance, more common LED based lamps could cause harmful interference for the observations. Thus, it is very important to perform continuous radio frequency interference (RFI) monitoring locally, in each radio observatory.

Schlüsselwörter

  • Frequency allocation
  • radio astronomy
  • radio frequency interference (RFI)
  • spectrum management
Uneingeschränkter Zugang

Relationship Between Solar Millimeter and Soft X-Ray Emissions

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 39 - 47

Zusammenfassung

Abstract

The connection between solar radio and soft X-ray emission has earlier been studied at various radio frequencies. For instance, the intensity peak times during solar flares have been compared between these two wavelength regimes. It has been reported that solar radio emission peaks before soft X-ray emission during a flare. However, opposite results have also been presented. In this study, we compare millimetre (8 mm) solar and soft X-ray emissions (0.5–4 Å and 1–8 Å). The radio observations were made at Metsähovi Radio Observatory of Aalto University in Finland between 2015 and 2019. The soft X-ray data were observed with GOES-15 (Geostationary Operational Environmental Satellite). The data show that the solar millimetre emission can peak either before or after soft X-ray peak emission. In this study, we present two different scenarios, which could explain the peaking time differences and behaviour. The first scenario proposes a tight connection between the millimetre (8 mm) and soft X-ray emissions, the second one is for cases where the emission mechanisms are more separate.

Schlüsselwörter

  • Chromosphere
  • corona
  • instrumentation and data management
  • radio bursts
  • radio emission
Uneingeschränkter Zugang

Magnetic Flux Switching Type Permanent Magnet Generator for Bicycles: Modelling and an Experimental Study

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 48 - 57

Zusammenfassung

Abstract

The article introduces two new designs of flux switching permanent magnet alternators with a radial and an axial arrangement of the inductor relative to the magnetic flux switch. The study presents the results of 3D magnetic flux modelling along with the outcomes of physical experiments. In the course of laboratory experiments, the results of theoretical estimations are compared with actual physical performance parameters. The results are presented in the form of power and output voltage curves in relation to the frequency and load current. The study proposes the practical application of the alternators based on the magnetic flux switching principle in the development of a bicycle generator. Laboratory test models are made of a laminated steel using a waste-free technology.

Schlüsselwörter

  • Bicycles
  • magnetic fields
  • modelling
  • permanent magnet machines
Uneingeschränkter Zugang

Axial Flux Switching Permanent Magnet Alternator with External Magnetic Cores

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 58 - 68

Zusammenfassung

Abstract

The article introduces the results of studying the magnetic field distribution in the alternator inductor with an axial arrangement of open magnetic cores (OMC) and external closure of magnetic fluxes. The study compares the efficiency of using magnetic fluxes from permanent magnets (PM) on the example of two model variants of inductors with OMC developed by the authors. The analysis of the density distribution of magnetic fluxes in OMC was carried out by 3D modelling of the magnetic field using EMWorks software. It has been shown that such generators can be manufactured using a waste-free technology for strip of OMC. This technology significantly reduces the production costs of OMC. By modelling the distribution of magnetic fluxes in the OMC of the inductor, the results of experimental studies and analysis of the created device show that the capacity of generator can be varied by changing its dimensions and the number of the toggle switches on the rotor. This allows the alternator to be adapted to the load requirements – power banks and bicycle electronics.

Schlüsselwörter

  • Bicycles
  • magnetic fields
  • modelling
  • permanent magnet machines
Uneingeschränkter Zugang

The Study of Properties of an Axial Flux Switching Permanent Magnet Alternator with Open Magnetic Cores

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 69 - 81

Zusammenfassung

Abstract

The article studies magnetic field distribution in the alternator inductors with an axial arrangement of open magnetic cores (OMC) and an external closure of the magnetic flux. The study compares the efficiency of magnetic flux utilization for four models with different modifications of the geometry of the magnetic circuit of inductors. The analysis of the density distribution of magnetic flux in OMC is carried out by 3D modelling of the magnetic field using EMWorks software. Based on the experimental study of the properties of the base model, the influence of the configuration of the magnetic circuit of the inductor on the efficiency of the alternator is shown. The results are presented in the form of tables and diagrams characterising changes in magnetic fluxes and electromotive force (EMF) in relative units. The results provide the grounds for assessing the potential and possible limits of optimization with respect to the size of air gaps and dimensions of the magnetic flux toggle switches. The study indicates that the proposed alternator can be adapted for various load requirements and optimized for various applications, such as charging power banks and powering bicycle electronics. The study also demonstrates that for such generators, OMC can be manufactured using a waste-free strip production technology.

Schlüsselwörter

  • Bicycle electronics
  • magnetic field distribution
  • modelling of magnetic fields
  • permanent magnet machines
Uneingeschränkter Zugang

Artificial Intelligence Meets Radio Astronomy

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 82 - 95

Zusammenfassung

Abstract

Artificial intelligence is widely spreading in all modern technologies. Such a very powerful methodology can have important applications in radio astronomy technology, for instance, in the new DBBC4 VLBI backend development project and in the low frequency array AntArr under development on the Etna slopes in Italy.

In the present paper, we describe the method currently adopted for those projects and some possible applications, which could provide substantial new features in this decade to the radio astronomy science and technology.

Schlüsselwörter

  • Artificial intelligence
  • DBBC
  • radio astronomy
  • radio interference
Uneingeschränkter Zugang

Hydrogen Hydraulic Compression System for Refuelling Stations

Online veröffentlicht: 23 Jun 2022
Seitenbereich: 96 - 105

Zusammenfassung

Abstract

The article investigates the properties and potential of compressed hydrogen as one of the most promising energy carriers in order to facilitate the development of energy storage capabilities and lay down a stable foundation for the future of a sustainable energy sector. The study considers the use of hydrogen, compressed at high pressure from 50 MPa to 100 MPa, at refuelling stations to supply electric cars. The technical properties of modern hydraulic compressors used for hydrogen accumulation in high pressure buffer containers are considered. The study shows that the design of hydraulic compressors in terms of their technical characteristics optimally corresponds to the primary requirements for their use as booster compressors at refuelling stations. The authors conclude with the proposal of an enhanced design of the hydraulic compressor with the use of fluid flow counters in a control system of a hydrogen compression cycle. The proposed technical solution provides for continuous monitoring of the hydrogen compression process that increases the reliability of control system operation.

Schlüsselwörter

  • Energy storage
  • fluid flow counters
  • hydrogen
  • high pressure
  • hydraulic compressors
  • refuelling stations

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