scholarly journals Automated method for calculating the Dst-index based on the wavelet model of geomagnetic field variations

2020 ◽  
Vol 44 (5) ◽  
pp. 797-808
Author(s):  
O.V. Mandrikova ◽  
A.A. Stepanenko

A method for calculating the geomagnetic activity index Dst (Dst-index) based on a wavelet model of geomagnetic field variations is proposed. The method allows values of the Dst-ndex to be automatically obtained with a 1-minute resolution. The method is tested using data from equatorial stations [1]. The paper describes a calculation algorithm and presents estimation results. The calculation results are compared with the classical approach and the Kyoto method [2]. It is shown that the proposed method allows values of the Dst index to be obtained in the on-line mode with an admissible error.

1972 ◽  
Vol 45 ◽  
pp. 16-21
Author(s):  
D. A. Andrienko ◽  
A. A. Demenko ◽  
I. M. Demenko ◽  
I. D. Zosimovich

The study of cometary brightness variations can be a good method for determining conditions in interplanetary space. In this work we compare the light curves of comets with curves showing variations in the geomagnetic field at times when the comets are near the ecliptic plane. We have used photometric observations made of 29 comets between 1881 and 1937. It is shown that an increase in the brightness of a comet is associated with an increase in the geomagnetic activity index and consequently with the influence of the solar corpuscular streams and solar wind.


2011 ◽  
Vol 2 (3) ◽  
pp. 205-210 ◽  
Author(s):  
Igor Savel'evich Fal'kovich ◽  
M. R. Olyak ◽  
Nikolai Nikolaevich Kalinichenko ◽  
I. N. Bubnov

Author(s):  
César Augusto Marasco Júnior ◽  
Bianca Ferreira da Silva ◽  
Rafaela Silva Lamarca ◽  
Paulo Clairmont Feitosa de Lima Gomes

1998 ◽  
Vol 11 (5-6) ◽  
pp. 331-338 ◽  
Author(s):  
Robert Milne ◽  
Mike Drummond ◽  
Patrick Renoux
Keyword(s):  
On Line ◽  

Author(s):  
Konstantin Kim ◽  
◽  
Konstantin Kim ◽  
Andrey Vataev ◽  
◽  
...  

We present the problem of optimization of cylindrical linear induction generators. The stator winding is located on the inner and outer cores of the magnetic system. The working fluid is a well-conducting liquid moving at a constant speed along the length of the channel. Since the generator is one of the elements of a complex installation the problem of optimizing it should be coordinated with a similar problem for the installation as a whole. This is done with the help the parameters common to all installation elements. Such parameters are the speed and flow rate of the working fluid. We describe the calculation algorithm with the use of computer technology. The efficiency and specific gravity of the generator are accepted as optimality criteria. The calculation results for a generator with the power of 20 MW are presented.


2021 ◽  
Vol 44 ◽  
pp. 63-66
Author(s):  
V.B. Belakhovsky ◽  
◽  
V.A. Pilipenko ◽  
K. Shiokawa ◽  
Y. Miyoshi ◽  
...  

The physical nature of Pg (pulsation giant) pulsations, which were observed in the magnetosphere by the Japanese satellite Arase, geostationary satellites GOES, and ground stations of the THEMIS and CARISMA networks, was investigated in this work. Pg pulsations belong to the Pc4 frequency range and are characterized by a very monochromatic shape. For the event on 5 June, 2018, according to the data from the Arase satellite, the Pg pulsation wave packet was recorded in the dawn sector during 3 hours. The pulsations are most pronounced in the radial component of the geomagnetic field, their frequency was about 11 mHz. Pg pulsations observed in the magnetosphere were accompanied by pulsations with the same period according to data from a number of ground-based magnetic stations located near the conjugate point. According to the data of ground stations, the pulsations were most strongly expressed in the Y-component of the geomagnetic field. Pg pulsations were accompanied by pulsations in electron and proton fluxes according to the Arase, GOES satellite observations. There are no clear phase relationships between geomagnetic pulsations and pulsations in charge particle fluxes. Pg pulsations were excited under quiet geomagnetic conditions (SYM-H = -10 nT, AE = 100-400 nT) on the recovery phase of the small geomagnetic storm. It is assumed that the expansion of the plasmasphere at low geomagnetic activity leads to an increase in the plasma density in the region of the geostationary orbit, which creates favorable conditions for the excitation of Pg pulsations due to the drift-bounce resonance of protons with the geomagnetic field lines oscillations in the magnetosphere.


2018 ◽  
Vol 36 (5) ◽  
pp. 1207-1225 ◽  
Author(s):  
Oksana V. Mandrikova ◽  
Igor S. Solovyev ◽  
Sergey Y. Khomutov ◽  
Vladimir V. Geppener ◽  
Dmitry M. Klionskiy ◽  
...  

Abstract. We suggest a wavelet-based multiscale mathematical model of geomagnetic field variations. The model is particularly capable of reflecting the characteristic variation and local perturbations in the geomagnetic field during the periods of increased geomagnetic activity. Based on the model, we have designed numerical algorithms to identify the characteristic variation component as well as other components that represent different geomagnetic field activity. The substantial advantage of the designed algorithms is their fully automatic performance without any manual control. The algorithms are also suited for estimating and monitoring the activity level of the geomagnetic field at different magnetic observatories without any specific adjustment to their particular locations. The suggested approach has high temporal resolution reaching 1 min. This allows us to study the dynamics and spatiotemporal distribution of geomagnetic perturbations using data from ground-based observatories. Moreover, the suggested approach is particularly capable of discovering weak perturbations in the geomagnetic field, likely linked to the nonstationary impact of the solar wind plasma on the magnetosphere. The algorithms have been validated using the experimental data collected at the IKIR FEB RAS observatory network. Keywords. Magnetospheric physics (storms and substorms)


1996 ◽  
Vol 7 (3) ◽  
pp. 464-471
Author(s):  
T A Depner ◽  
P R Keshaviah ◽  
J P Ebben ◽  
P F Emerson ◽  
A J Collins ◽  
...  

Quantitation of hemodialysis by measuring changes in blood solute concentration requires careful timing when taking the postdialysis blood sample to avoid errors from postdialysis rebound and from recirculation of blood through the access device. It also requires complex mathematical interpretation to account for solute disequilibrium in the patient. To circumvent these problems, hemodialysis can be quantified and its adequacy assessed by direct measurement of the urea removed in the dialysate. Because total dialysate collection is impractical, an automated method was developed for measuring dialysate urea-nitrogen concentrations at frequent intervals during treatment. A multicenter clinical trial of the dialysate monitoring device, the Biostat 1000 (Baxter Healthcare Corporation, McGaw Park, IL) was conducted to validate the measurements of urea removed, the delivered dialysis dose (Kt/V), and net protein catabolism (PCR). The results were compared with a total dialysate collection in each patient. During 29 dialyses in 29 patients from three centers, the paired analysis of urea removed, as estimated by the dialysate monitor compared with the total dialysate collection, showed no significant difference (14.7 +/- 4.7 g versus 14.8 +/- 5.1 g). Similarly, measurements of Kt/V and PCR showed no significant difference (1.30 +/- 0.18 versus 1.28 +/- 0.19, respectively, for Kt/V and 42.3 +/- 15.7 g/day versus 52.2 +/- 17.4 g/day for PCR). When blood-side measurements during the same dialyses were analyzed with a single-compartment, variable-volume model of urea kinetics, Kt/V was consistently overestimated (1.49 +/- 0.29/dialysis, P < 0.001), most likely because of failure to consider urea disequilibrium. Because urea disequilibrium is difficult to quantitate during each treatment, dialysate measurements have obvious advantages. The dialysate monitor eliminated errors from dialysate bacterial contamination, simplified dialysate measurements, and proved to be a reliable method for quantifying and assuring dialysis adequacy.


2021 ◽  
Author(s):  
Lyndsay Roach

The study of networks has been propelled by improvements in computing power, enabling our ability to mine and store large amounts of network data. Moreover, the ubiquity of the internet has afforded us access to records of interactions that have previously been invisible. We are now able to study complex networks with anywhere from hundreds to billions of nodes; however, it is difficult to visualize large networks in a meaningful way. We explore the process of visualizing real-world networks. We first discuss the properties of complex networks and the mechanisms used in the network visualizing software Gephi. Then we provide examples of voting, trade, and linguistic networks using data extracted from on-line sources. We investigate the impact of hidden community structures on the analysis of these real-world networks.


2020 ◽  
Vol 22 (3) ◽  
pp. 132-139
Author(s):  
A. V. Denisov ◽  
M. D. Stepanov ◽  
N. A. Haraldin ◽  
A. V. Stepanov ◽  
A. I. Borovkov ◽  
...  

Abstract. In the work, a review of scientific articles on the behavior of tissues and organs of the human body under local mechanical effects on it, as well as a description of the physico-mechanical properties of biological materials. The selection of mechanical behavior for each biological material as part of a mathematical model of the human torso was carried out, its finite element model was created, validation experiments were modeled using data presented in the literature. An original calculation model of a human torso with a tuned interaction of organs with each other was developed. Contact interaction parameters are determined. The developed computational model of a human torso was verified based on data from open sources for an experiment with mechanical action by a cylindrical impactor. An algorithm for processing pressure and acceleration graphs has been implemented in order to obtain tolerance curves. A specialized modular program has been created for the automated processing of calculation results and the output of the main results. 42 numerical tests were carried out simulating the entry of a steel ball into each of 21 zones for power engineers of 40 and 80 J. According to the results of the tests for each organ, pressure and acceleration tolerance curves were obtained, animations of the behavior of organs under shock were created, visualization of the pressure field propagation in organs was obtained torso.


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