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1
Ljutenko, L. A., and V. M. Mikhailov. "Expansion of cylindrical tubular workpieces on high-voltage magnetic-pulse installation with controlled vacuum discharger." Electrical Engineering & Electromechanics, no. 3 (June 23, 2021): 42–46. http://dx.doi.org/10.20998/2074-272x.2021.3.07.
Повний текст джерелаАнотація:
Purpose. An experimental verification of the existence of a range of values for the parameters of the capacitive energy storage of the magnetic-pulse installations with controlled vacuum discharger, in which, with a high probability, there is a «cut» of the discharge current pulses and the expansion of cylindrical thin-walled tubular workpieces using an external coil. Methodology. High voltage magnetic-pulse installation of NTU «KhPI» with controlled vacuum discharger, multiturn coil with inside dielectrical die and inside aluminum alloy workpiece are used. The capacitance and charge voltage of capacitive energy storage are changed. Discharge current pulses are measured by Rogowski coil and the oscillograph. Results. Parts of complicated shape are made by expansion of cylindrical tubular workpieces with help of external coil. Pressed metallic tubular part is removable from inner dielectric rod. Originality. The frequency of «cut» pulse is defined by negative magnetic field pressure amplitude. It is shown that we must coordinate this frequency and charge voltage with capacitive storage parameters by high probability of pulse «cut». Practical value. It is shown how to use installations with controlled vacuum dischargers in magnetic forming technology based on «cut» pulses.
2
Batygin, Yu V., S. O. Shinderuk, E. O. Chaplygin, and D. V. Fendrikov. "DOUBLE-CIRCUIT RESONANT ELECTRIC POWER AMPLIFIER FOR MAGNETIC-PULSE PROCESSING OF METALS." Tekhnichna Elektrodynamika 2022, no. 3 (May 23, 2022): 29–36. http://dx.doi.org/10.15407/techned2022.03.029.
Повний текст джерелаАнотація:
The authors propose and substantiate the functionality of a magnetic-pulse installation consisting of two blocks, the first of which is a resonant double-circuit charger of a capacitive energy storage, and the second block is a discharge circuit with an inductor-tool for performing a given production operation. It is shown that the voltage changes in time according to an exponentially growing harmonic law. It was found that the amplitude of the voltage across the capacitor can be regulated by varying the characteristics of the coupling transformer between the circuits and the characteristics of the circuit of the reactive power conversion unit. Numerical assessments of the characteristics of the charging process showed a high efficiency of voltage formation on the capacitive storage due to resonance phenomena (the transformation ratio is equal to the Q-factor of the circuit ~ 20), which is not comparable with the well-known traditional indicators of induction methods. In terms of phase – the length in time to the maximum charge in the adopted circuit of the active electric power amplifier is set by the inequality - That is, after ~ 30 periods of charging current, the excited voltage reaches a maximum (~ 20 times higher than the source voltage), which will correspond to the end of the transient process and the establishment of a steady state of operation. An example of calculating the characteristics of an elementary resonant base illustrates the effective capabilities of a magnetic-pulse installation, consisting of a resonant charger of a capacitive energy storage and a load in the form of an inductor-tool for flat stamping of metal products. It was found that the square of the ratio of operating frequencies in the load unit and the reactive power amplification unit quantitatively determines the fundamental possibility of resonant amplification of the active electrical energy of a harmonic signal. References 12, figures 5.
3
Alifanov, A. V., D. A. Tsionenko, A. M. Miliukova, A. I. Harchanin, and V. V. Maleronak. "SPECIAL FEATURES OF MAGNETIC PULSE HARDENING PROCESSING OF STEEL CYLINDRICAL PRODUCTS OF VARIABLE CROSS-SECTION." Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), no. 2 (July 4, 2017): 88–96. http://dx.doi.org/10.21122/1683-6065-2017-2-88-96.
Повний текст джерелаАнотація:
The calculations of the magnetic field induction and the magnetic field intensity were carried out by the Finite Element Method (FEM) with the use of the software FEMM. The cylindrical inductor of the Magnetic-Pulse Installation (MPI) generates the magnetic field near the surface of the cylindrical steel product as of the uniform as well as variable cross section. It is shown that the regions of the products of the complex cross-section located at the minimal distance to the helix inductor are exposed to highest level of hardening. It is necessary to increase the current pulse in the inductor or to use a split inductor with the variable inner diameter repeating the product profile for hardening of the product regions located at large distances from inductor. The side surfaces of protrusions that are perpendicular to the axis of the system are not exposed to hardening due to the low gradient of the energy density of magnetic field near its surface. In the case of close proximity of the protrusions (for distance less than 1 cm), the material on the product surface in the space between protrusions is not exposedto sufficient hardening.
4
Sudenkov, Yuri V., Svetlana Atroshenko, Ivan Smirnov, Natalya Naumova, and Xue Yin Sun. "Investigation of High-Speed Loading Effects on the Properties of Ferromagnetic Alloys Processed in an External Magnetic Field." Applied Mechanics and Materials 566 (June 2014): 542–47. http://dx.doi.org/10.4028/www.scientific.net/amm.566.542.
Повний текст джерелаАнотація:
The behavior of the ferromagnetic alloy based on Fe-Cr-Co under high-speed loading is presented. Three types of samples were prepared with different pre-treatments: quenching only; quenching and ageing; and quenching and ageing under an intense external magnetic field. The sub-microsecond impact load was created by the installation for the electrical explosion of foils. The developed method of loading allows a pressure pulse to be registered before impact on a flat sample and after its exit to a free surface of this sample. Changes in the mechanical properties of the ferromagnetic alloy with various technologies of preliminary processing before and after shock loading are discussed.
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Glushchenkov, V. A., L. T. Volova, I. A. Belyaeva, V. V. Boltovskaya, V. V. Rossinskaya, A. I. Ignatenko, I. F. Nefedova, and L. N. Kulagina. "ACTION OF A HIGH-INTENSITY PULSED MAGNETIC FIELD ON A HUMAN DERMAL FIBROBLASTS IN CULTURE." Izvestiya of Samara Scientific Center of the Russian Academy of Sciences 22, no. 5 (2020): 14–22. http://dx.doi.org/10.37313/1990-5378-2020-22-5-14-22.
Повний текст джерелаАнотація:
The influence of pulsed magnetic fields (PMF) with different values of field intensity H, discharge current frequency f and a number of pulses n on dermal fibroblasts was studied in vitro. A specialized pulse-magnetic installation «PMI-Bio» and a measuring stand for creating and monitoring the specified parameters of the PMF were created. Four series of experiments with longitudinal and transverse action of the PMF at a field intensity of 3.76⋅106 – 8.7⋅106 A/m (500 and 1000 J) were carried out. It was found that the longitudinal action of the PMF at 500 J does not lead to cell death, preserves all their structural components, and is safe for primary fibroblast cultures. The use of high-intensity pulsed magnetic fields (HI PMF) at 1000 J in both longitudinal and transverse directions leads to a violation of cell adhesion to the culture plastic and changes in the structure of dermal fibroblasts, up to their death.
6
Titov, M., G. Nepomnyashchev, and D. Dorofeeva. "Application of electro-hydraulic shock in concrete technology." Journal of Physics: Conference Series 2131, no. 5 (December 1, 2021): 052002. http://dx.doi.org/10.1088/1742-6596/2131/5/052002.
Повний текст джерелаАнотація:
Abstract The aspects, related to the influence of the electrohydraulic shock method use in a water-cement slurry passing in a closed chamber (activation reactor) with a pre-applied pressure to the system under various processing modes are highlighted in the article. In order to test the effect of this method on water-cement slurry, an installation was developed, consisting of: a high-voltage source, a high-voltage diode, capacitor banks, a closing element and an activation reactor. The necessary experiments were carried out on the completed installation. The procedure for conducting experiments is described in the work, shows a schematic diagram of the installation for performing activation, a diagram of the reactor, and the processing modes. Several activation modes were considered, depending on: the number of pulses (1-4), pulse energy (0.5-8 kJ), water-cement ratio (0.2-0.35), time intervals for starting treatment from the moment the cement was mixed with water (0 -120 minutes), volume and shape of the container (activation reactor), holding temperature (20-60°C), etc. According to the results of the data obtained, it was experimentally established that the use of electric pulse treatment of water-cement suspension has a positive effect on strength (cup compressive strength) indicators, obtained as a result of processing cement stone samples at different times of hardening (1-3 days). The compressive strength of the treated specimens’ increases in comparison with the untreated specimens, increase in strength reaches up to 45%, depending on the activation mode. The resulting effect was achieved due to many factors (high pressure, magnetic, temperature, energy, ultrasonic and other influences), which were applied in the most optimal period of time (stage) of the cement grain hydration process.
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Baev, A. R., A. I. Мitkovets, M. V. Asadchaya, and A. L. Mayorov. "Impulsively-Laser Excitation and Propagation of Ultrasonic Waves through Nanomagnetic Fluid." Devices and Methods of Measurements 12, no. 3 (October 15, 2021): 211–19. http://dx.doi.org/10.21122/2220-9506-2021-12-3-211-219.
Повний текст джерелаАнотація:
Magnetic fluids belong to the class of nanomaterials with a high gain of light absorption, aggregative and sedimentation stability as well as controllability by external fields, which is of interest to use in the field of optoacoustics. The purpose of the work was to experimentally study the effect of the optoacoustic transformation in a magnetic fluid, depending on the concentration of magnetic colloidal particles, boundary conditions, intensity of the laser as well as to identify the possibilities of using the magnetic fluid as an element of the optoacoustic transformation in a number of applications.A brief analysis of the optoacoustic transformation mechanism in a magnetic fluid was carried out and a technique and an installation that implements the shadow measurement variant developed. A Lotis type laser was used as a source of ultrasonic pulse-laser excitation in magnetic fluids. A quartz and air were used as a material transmitting the energy of laser radiation in a magnetic fluid. Receiving of ultrasound signals was made by a piezoelectric probe at a working frequency of 5 MHz. In the measurement process, the concentration of the dispersed phase in tmagnetic fluid was varied from zero to 8 % and the energy in the impulse – from zero to 10 mJ.For the first time, it was established that: a) an amplitude of the function of the optoacoustic transformation in a magnetic fluid, depending on the concentration of the dispersed phase, has a maximum determined by the fluid physical properties and boundary conditions; b) for all samples within the measurement error, a quasilinear dependence of the specified amplitude of energy in the laser pulse in the range of 0–8 MJ has been established.A number ways of the optoacoustic effects in magnetic fluids to use in ultrasonic testing, measuring the intensity of the laser radiation had been suggested.
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Sanchez, Francisco, Ferran Albajar, Alessandro Lo Bue, Stephano Alberti, Konstantinos Avramidis, Tullio Bonicelli, Alex Bruschi, et al. "Metrology techniques for the verification of the alignment of the EU gyrotron prototype for ITER." EPJ Web of Conferences 203 (2019): 04015. http://dx.doi.org/10.1051/epjconf/201920304015.
Повний текст джерелаАнотація:
The EU gyrotron for the ITER Electron Cyclotron (EC) heating system has been developed in coordinated efforts of the EGYC Consortium, Thales ED (TED) and Fusion for Energy (F4E) and under the supervision of ITER Organization Central Team. After the successful verification of the design of the 1MW, 170 GHz hollow cylindrical cavity gyrotron operating at the nominal TE32,9 mode with a short pulse gyrotron prototype at KIT, an industrial CW gyrotron prototype was manufactured by TED and tested at ~0.8 MW output power and 180 s pulse duration, which is the limit of the HV power supply currently available at KIT. The experiments are being continued at SPC in 2018 to extend further the pulse duration, taking advantage of the existing CW full-power capabilities of the gyrotron test facility recently upgraded for the FALCON project. The gyrotron cavity interaction is very sensitive to the alignment of the internal mechanical parts of the gyrotron tube with the magnetic field generated by the superconducting magnet within a typical range of 0.2 – 0.5 mm. The control of the tolerances and deformations becomes therefore critical to achieving the target performances. With the EU gyrotron prototype it was possible to adjust the alignment of the gyrotron tube with respect to the magnetic field axis during the installation and commissioning phase. The actual shift and tilt movements were verified using advanced metrology methods such as photogrammetry. In this paper, the alignment control techniques and procedures will be discussed also in view of enhancing the reproducibility of gyrotron performance during series production.
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Zlobin, D. V., and L. V. Volkova. "INFLUENCE OF DYNAMIC MAGNETIZATION TO IMPROVE THE EFFICIENCY OF ELECTROMAGNETIC-ACOUSTIC TRANSFORMATION WITH WAVEGUIDE CONTROL RODS." Devices and Methods of Measurements 8, no. 3 (September 27, 2017): 236–45. http://dx.doi.org/10.21122/2220-9506-2017-8-3-236-245.
Повний текст джерелаАнотація:
The disadvantage of the electromagnetic-acoustic (EMA) method receiving ultrasonic waves are low efficiency. The traditional way to enhance its effectiveness is increase the bias field. The aim of the study was research the way to improve the efficiency of the EMA transformation, using a time-varying bias field.The researches held with the help of a specially designed installation that allows the magnetization to be performed by a constant and alternating magnetic field (dynamic bias), synchronously with the passage of the received pulse. The object of the study were rods made of different grades of steel with a diameter of 4–6 mm, in which the symmetrical zero mode S0 of the rod wave was excited by the EMA method (in the frequency range of about 40 kHz). A comparative analysis of the amplitudes and form pulses of multiple reflections during static and dynamic reversal of magnetization and with a full cycle of magnetization reversal conducted.The result of the efficiency measurements EMA reception during static and dynamic bias found a significant (up to 5 times) increase in the signal amplitude on the receiving transducer. Taking into account that the main contribution to the excitation mechanism and the reception mechanism made the magnetostrictive effect on low frecuncy, it can assumed that using a dynamic bias field is impacting significant on the effective mobility of magnetic domains (that is changes the dynamic magnetic susceptibility of the material). It is established that it is possible to monitor steel at lower values of the bias field, and, consequently, to reduce the mass dimensions of the magnetic system.Thus, in the course of the researchers found of effect of dynamic bias and effect of dynamic bias increase acoustic pulse amplitude of the signal of the received EMA method. Using this method will improve the quality EMA testing by creating more efficient EMA transducer. Taking into account that the value of the detected effect depends significantly on the steel grade, we can assume its possible application in the methods of express analysis, estimation of structural and stressed states.
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Smeibidl, Peter, Karel Prokes, Mark Bird, Oleksandr Prokhnenko, Hartmut Ehmler, and David Tennant. "The High Magnetic Field Magnet for Neutron Studies at Helmholtz Zentrum Berlin." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C164. http://dx.doi.org/10.1107/s2053273314098350.
Повний текст джерелаАнотація:
High magnetic fields can create exotic states which challenge our basic understanding of matter. This requires a deep and precise knowledge of the spatial ordering of atoms and associated magnetic moments. Particularly interesting would be to disclose magnetic field dependency of various fluctuations and collective modes. Such information can be obtained from neutron scattering experiments. The Helmholtz Zentrum Berlin (HZB) is known for its sample environment that is available for both internal and external users. Presently, a project that combines dedicated scattering instrument (EXED) with a horizontal hybrid solenoid magnet with tapered 300cones is being finalized at HZB. To achieve an optimal performance, a 13 T superconducting Nb3Sn cable-in-conduit coil is combined with resistive insert coils of 12 T to 18 T (see figure), depending on electric power (between 4.4 and 8.0 MW), to give a maximum of 25 to 31 T. The magnet that has been developed in collaboration with the National High Magnetic Field Laboratory of Florida State University, Tallahassee, FL, USA [1] provides a 50 mm diameter room temperature bore. For sample cooling a 3He cryostat with a pulse tube precooling stage is being developed. The magnet will be permanently mounted at the dedicated time-of-flight instrument EXED at the end of a multispectral neutron guide NL4a, about 76 m away from the neutron source. The EXED instrument is optimized for diffraction under restricted geometrical conditions and is being upgraded to include inelastic option. This unique experimental setup is supposed to play a major role in high-field neutron studies and should be ready for use in early 2015. The contribution describes not only the most important design features of the system, the outline of the building for the technical infrastructure and the status of the installation and commissioning but also the scientific possibilities and limitations of the setup.
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Belyaeva, I. A., L. I. Bashirova, V. A. Glushchenkov, N. A. Rodenko, A. K. Fakhretdinova, and D. D. Muminov. "INFLUENCE OF A PULSE MAGNETIC FIELD OF HIGH VOLTAGE ON THE INDICATORS OF ANTI-AGGREGATION ACTIVITY OF THE CHEMICAL SUBSTANCE AND THE PREPARED PHARMACY PREPARATION PENTOXYPLIN." Izvestiya of Samara Scientific Center of the Russian Academy of Sciences 23, no. 4 (2021): 45–50. http://dx.doi.org/10.37313/1990-5378-2021-23-4-45-50.
Повний текст джерелаАнотація:
It was found that the pharmaceutical preparation of pentoxifylline, treated with a pulsed magnetic field (PMF), changes the antiaggregatory properties.The pharmaceutical preparation contains the pure substance of pentoxifylline and a number of excipients. To understand the mechanism of changes in the antiaggregatory activity of a pharmaceutical preparation, the goal was to further investigate the effect of PMF parameters on its chemically pure substance.PMF processing was carried out on the «MIU Bio» installation with a single exposure at a field strength in the range (0.48–1.17) 106 A/m at discharge circuit frequencies (8–50) 103 Hz.Experiments have shown that the effect of PMF on the pure substance of pentoxifylline did not cause significant changes in its antiaggregatory activity. This result made it possible to get one step closer to understanding the mechanism of the effect of PMF on a given drug. Apparently, the reason for the change in the biological effectiveness of the pharmaceutical pentoxifylline treated with PMF lies in the effect of impurities, which will be the focus of further research.
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ZVORYKIN, V. D., S. V. ARLANTSEV, V. G. BAKAEV, O. V. RANTSEV, P. B. SERGEEV, G. V. SYCHUGOV, and A. Yu TSERKOVNIKOV. "Transport of electron beams and stability of optical windows in high-power e-beam-pumped krypton fluoride lasers." Laser and Particle Beams 19, no. 4 (October 2001): 609–22. http://dx.doi.org/10.1017/s0263034601194085.
Повний текст джерелаАнотація:
Two of the key issues of a krypton fluoride (KrF) laser driver for inertial fusion energy are the development of long life, high transparency pressure foils (to isolate vacuum in the electron beam diode from a working gas in the laser chamber), and the development of durable, stable, optical windows. Both of these problems have been studied on the single-pulse e-beam-pumped KrF laser installation GARPUN. We have measured the transport of electron beams (300 keV, 50 kA, 100 ns, 10 × 100 cm) through aluminum-beryllium and titanium foils and compared them with Monte Carlo numerical calculations. It was shown that 50-μm thickness Al-Be and 20-μm Ti foils had equal transmittance. However, in contrast to Ti foil, whose surface was strongly etched by fluorine, no surface modification nor fatal damages were observed for Al-Be foils after ∼1000 laser shots and protracted fluorine exposure. We also measured the 8% reduction in the transmission of CaF2 windows under irradiation by scattered electrons when they were set at 8.5 cm apart from the e-beam-pumped region. However an applied magnetic field of ∼0.1 T significantly reduced electron scattering both across and along the laser cell at typical pumping conditions with 1.5 atm pressure working gas. Thus the e-beam-induced absorption of laser radiation in optical windows might be fully eliminated in an e-beam-pumping scheme with magnetic field guiding.
13
Xu, G. S., L. Wang, D. M. Yao, G. Z. Jia, C. F. Sang, X. J. Liu, Y. P. Chen, et al. "Physics design of new lower tungsten divertor for long-pulse high-power operations in EAST." Nuclear Fusion 61, no. 12 (November 24, 2021): 126070. http://dx.doi.org/10.1088/1741-4326/ac3297.
Повний текст джерелаАнотація:
Abstract A new lower tungsten divertor has been developed and installed in the EAST superconducting tokamak to replace the previous graphite divertor with power handling capability increasing from <2 MW m−2 to ∼10 MW m−2, aiming at achieving long-pulse H-mode operations in a full metal wall environment with the steady-state divertor heat flux of ∼10 MW m−2. A new divertor concept, ‘corner slot’ (CS) divertor, has been employed. By using the ‘corner effect’, a strongly dissipative divertor with the local buildup of high neutral pressure near the corner can be achieved, so that stable detachment can be maintained across the entire outer target plate with a relatively lower impurity seeding rate, at a separatrix density compatible with advanced steady-state core scenarios. These are essential for achieving efficient current drive with low-hybrid waves, a low core impurity concentration and thus a low loop voltage for fully non-inductive long-pulse operations. Compared with the highly closed small-angle-slot divertor in DIII-D, the new divertor in EAST exhibits the following merits: (1) a much simpler geometry with integral cassette body structure, combining vertical and horizontal target plates, which are more suitable for actively water-cooled W/Cu plasma facing components, facilitating installation precision control for minimizing surface misalignment, achieving high engineering reliability and lowering the capital cost as well; (2) it has much greater flexibility in magnetic configurations, allowing for the position of the outer strike point on either vertical or horizontal target plates to accommodate a relatively wide triangularity range, δ l = 0.4–0.6, thus enabling to explore various advanced scenarios. A water-cooled copper in-vessel coil has been installed under the dome. Five supersonic molecular beam injection systems have been mounted in the divertor to achieve faster and more precise feedback control of the gas injection rate. Furthermore, this new divertor allows for double null divertor operation and slowly sweeping the outer strike point across the horizontal and vertical target plates to spread the heat flux for long-pulse operations. Preliminary experimental results demonstrate the ‘corner effect’ and are in good agreement with simulations using SOLPS-ITER code including drifts. The EAST new divertor provides a test-bed for the closed divertor concept to achieve steady-state detachment operation at high power. Next step, a more closed divertor, ‘sharp-cornered slot’ divertor, building upon the current CS divertor concept, has been proposed as a candidate for the EAST upper divertor upgrade.
14
Yusupov, Rinat Yu, and Vladimir Glushchenkov. "Multi-Block and Multi-Station Pulse-Magnetic Installations." Key Engineering Materials 684 (February 2016): 507–10. http://dx.doi.org/10.4028/www.scientific.net/kem.684.507.
Повний текст джерелаАнотація:
The paper describes principles of construction of multi-block and multi-station pulse-magnetic installations. Main requirements for selection of elements of energy storages of installations with high stored energy and high frequency of the discharging current are presented. Examples of hardware implementation of the installations are shown.
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Kostriukov, Evgenii E., and Rinat Yu Yusupov. "Design Features of the Small-Scale PMI Power Unit." Key Engineering Materials 684 (February 2016): 530–34. http://dx.doi.org/10.4028/www.scientific.net/kem.684.530.
Повний текст джерелаАнотація:
The paper is dedicated to description of the design of special-purpose small-scale pulse-magnetic installations. Recommendations are given on the choice of the element base of energy storages and the high-voltage charging unit for various embodiments. The paper presents main parameters of small-scale pulse capacitors and of current switches of foreign and domestic manufacturers.
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Buyko, A. M., O. M. Burenkov, V. K. Chernyshev, S. F. Garanin, S. D. Kuznetsov, A. I. Kuzyayev, V. N. Mokhov, et al. "Changing mass liner system for generation of soft X rays." Laser and Particle Beams 15, no. 1 (March 1997): 133–38. http://dx.doi.org/10.1017/s026303460001082x.
Повний текст джерелаАнотація:
Powerful pulse installations are usually used to produce large yields of X-ray radiation. With an increase of the stored energy up to 100 MJ, the costof a single experiment on these installations becomes comparable to the cost of a shot with explosive magnetic generators (EMG), according to expert estimates. The physical scheme of a device with a changeable mass liner forlarge soft X-ray (in the range of 0.3 to 0.5 keV) yields eneration is investigated. The scheme investigated is substantially free from difficulties connected with high precision liners and fast switches for current pulse sharpening.
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Nizhevsky, Viktor, Sergey Berezka, Olena Fedoseenko, and Ilia Nizhevsky. "CORRECTION OF THE METHOD FOR MEASURING THE AMPLITUDES OF THE CURRENT OF THE IMPULSE ALONG THE LONG EARTH ELECTRODE." Bulletin of the National Technical University "KhPI". Series: Energy: Reliability and Energy Efficiency, no. 1 (2) (July 2, 2021): 79–85. http://dx.doi.org/10.20998/2224-0349.2021.01.11.
Повний текст джерелаАнотація:
An improved method for measuring the amplitude reduction of the lightning current impulse as it flows from the beginning to the end of long horizontal earthing arrangement using ferromagnetic recorders has been substantiated. Two existing methods of pulse amplitude measurements at high voltages, the magnetic recording method and the method using a shunt, are used in justification. It is noted that in a number of cases it becomes necessary to determine the decrease in the pulse amplitude as it flows on a long object. This leads to the need to develop a method for performing such measurements. As an example, a long horizontal earth electrode was investigated when a lightning current pulse moves on it. Based on experimental studies in natural conditions, an improved method for measuring the decrease in the amplitude of the lightning current impulse along a long earth electrode is proposed. The proposed method has a measurement error not exceeding 10 %, and allows simultaneous measurements of the amplitude of the current strength at given points of the object, which can amount to tens or even hundreds. This method is implemented in a simple design and has an affordable manufacturing cost. The results of the experiments performed make it possible to recommend the corrected measurement method for practical use on existing electrical installations. The use of ferromagnetic recorders for recording and measuring the lightning current in areas of complex earthing arrangements is relevant for practical reasons, which include the possibility of measuring during a long wait and long-term storage of measurement results, does not require additional power sources and provides the possibility of synchronous measurements at various points of the grounding device. An important feature of the method is safety for technical equipment and personnel.
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Ndunda, Moses, Alix Dehayem-Kamadjeu, and David Waswa. "Impact of Temperature and Relative Humidity on PMD in Directly Buried Optical Fibre Cables in Semi-Arid and Tropical Highlands in Kenya." International Journal of Optics 2018 (December 2, 2018): 1–6. http://dx.doi.org/10.1155/2018/1653767.
Повний текст джерелаАнотація:
The telecommunication industry has implemented fibre deployment guidelines that reliably safeguard cable health during installation in the field. While installed fibre cables remain buried in the field, temperature and moisture in the locality subject them to mechanical expansions and corrosion. Directly buried fibre cables experience accelerated degradation that results from exposure to harsh environments. This increases pulse spreading and overlaps, with a mean time duration, known as Differential Group Delay (DGD), on the signal, as it propagates along the cable. DGD is stochastic; thus, Mean DGD is determined and presented as Polarization Mode Dispersion (PMD). This work undertook a real life assessment of how fluctuations in temperature and relative humidity influence PMD in directly buried fibre optical links, in a case study that focused on the fibre cable network owned by Liquid Telecom Kenya. The network spans across two key climatic ecosystems, namely, rift valley highlands and northern lowlands. The analysis revealed that fibre cables experience higher PMD in semi-arid areas by a factor of 2.6, compared to highland areas.
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Reshetnyak, N. G., V. P. Romas´ko, and I. A. Chertishev. "DEVELOPMENT OF A PULSE SOLENOID OF MAGNETIC FIELD AMPLITUDE UP TO 0.5 T AND A PULSE SINUSOIDAL CURRENT GENERATOR FOR ITS POWER SUPPLY." Problems of Atomic Science and Technology, June 1, 2020, 19–22. http://dx.doi.org/10.46813/2020-127-019.
Повний текст джерелаАнотація:
The magnetic system of the installation to control the transverse dimensions of an electron beam formed by a magnetron gun with a secondary emission cathode was updated. An additional solenoid with pulsed power supply located in a vacuum chamber at a distance of 0.05...0.1 m from the gun’s edge will be used in experiments. The solenoid design was selected and calculated. Possibility of a magnetic field generation of amplitude of up to 0.5 T at amplitude of the pulse current of ~ 1.5 kA, was demonstrated. The field has a uniform area at the level of ± 5% over the length of ~ 0.2 m.
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Borneis, S., T. Laštovička, M. Sokol, T. M. Jeong, F. Condamine, O. Renner, V. Tikhonchuk, et al. "Design, installation and commissioning of the ELI-Beamlines high-power, high-repetition rate HAPLS laser beam transport system to P3." High Power Laser Science and Engineering 9 (2021). http://dx.doi.org/10.1017/hpl.2021.16.
Повний текст джерелаАнотація:
Abstract The design and the early commissioning of the ELI-Beamlines laser facility’s 30 J, 30 fs, 10 Hz HAPLS (High-repetition-rate Advanced Petawatt Laser System) beam transport (BT) system to the P3 target chamber are described in detail. It is the world’s first and with 54 m length, the longest distance high average power petawatt (PW) BT system ever built. It connects the HAPLS pulse compressor via the injector periscope with the 4.5 m diameter P3 target chamber of the plasma physics group in hall E3. It is the largest target chamber of the facility and was connected first to the BT system. The major engineering challenges are the required high vibration stability mirror support structures, the high pointing stability optomechanics as well as the required levels for chemical and particle cleanliness of the vacuum vessels to preserve the high laser damage threshold of the dielectrically coated high-power mirrors. A first commissioning experiment at low pulse energy shows the full functionality of the BT system to P3 and the novel experimental infrastructure.