scholarly journals MHD-waves in the geomagnetic tail: A review

10.12737/7168 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 4-22 ◽  
Author(s):  
Анатолий Леонович ◽  
Anatoliy Leonovich ◽  
Виталий Мазур ◽  
Vitaliy Mazur ◽  
Даниил Козлов ◽  
...  
Keyword(s):  
Numerical Models ◽  
Experimental Studies ◽  
Low Frequency ◽  
Detailed Comparison ◽  
Mhd Waves ◽  
Theoretical Studies ◽  
Geomagnetic Tail ◽  
Magnetopause Oscillations ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

This article presents the review of experimental and theoretical studies on ultra-low-frequency MHD oscillations of the geomagnetic tail. We consider the Kelvin–Helmholtz instability at the magnetopause, oscillations with a discrete spectrum in the “magic frequencies” range, the ballooning instability of coupled Alfvén and slow magnetosonic waves, and “flapping” oscillations of the current sheet of the geomagnetic tail. Over the last decade, observations from THEMIS, CLUSTER and Double Star satellites have been of great importance for experimental studies. The use of several spacecraft allows us to study the structure of MHD oscillations with high spatial resolution. Due to this, we can make a detailed comparison between theoretical results and those obtained from multi-spacecraft studies. To make such comparisons in theoretical studies, in turn, we have to use the numerical models closest to the real magnetosphere.

Strong coupling: resonant effects

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Strong Coupling ◽  
Experimental Studies ◽  
Strong Coupling Regime ◽  
Theoretical Studies ◽  
Stimulated Scattering ◽  
Quantum Theories ◽  
Pump Probe ◽  
Exciton Polaritons ◽  
Linear Optical Properties ◽  
Experimental And Theoretical Studies

This chapter presents experimental studies performed on planar semiconductor microcavities in the strong-coupling regime. The first section reviews linear experiments performed in the 1990s that evidence the linear optical properties of cavity exciton-polaritons. The chapter is then focused on experimental and theoretical studies of resonantly excited microcavity emission. We mainly describe experimental configuations in which stimulated scattering was observed due to formation of a dynamical condensate of polaritons. Pump-probe and cw experiments are described in addition. Dressing of the polariton dispersion and bistability of the polariton system due to inter-condensate interactions are discussed. The semiclassical and the quantum theories of these effects are presented and their results analysed. The potential for realization of devices is also discussed.

scholarly journals Numerical simulation of the stress-strain state of complex-reinforced elements

2019 ◽  
Vol 13 (2) ◽  
pp. 110-115
Author(s):  
Olena Krantovska ◽  
Mykola Petrov ◽  
Liubov Ksonshkevych ◽  
Matija Orešković ◽  
Sergii Synii ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Strain State ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Theoretical Studies ◽  
Stress Strain ◽  
Narrow Strip ◽  
Stress Strain State ◽  
Graphical Environment ◽  
Experimental And Theoretical Studies

The article describes a developed technique of a numerical simulation of the stress-strain state of complex-reinforced elements, which allows you to create models of double-span continuous. The performed experimental and theoretical studies allowed us to carry out the testing of the developed design model and to justify the reliability of the proposed numerical simulation methodology. The results of the experimental studies were compared with those of the theoretical studies. The theoretical calculus algorithm was developed by using the finite element method. Theoretical calculations were performed by using the mathematical-graphical environment software system LIRA-SOFT and the mathematical and computer program MATLAB. On the basis of the experimental research, the iso-fields of displacements and stresses in the materials of an eccentrically compressed beam with a small bend of the slab were constructed, which collapse behind the inclined narrow strip of concrete and displacements and stresses in the materials of the eccentrically stretched beam, which is destroyed due to the yield of the upper mounting armature.

scholarly journals Experimental and theoretical studies on the photodegradation of 2-ethylhexyl 4-methoxycinnamate in the presence of reactive oxygen and chlorine species

2014 ◽  
Vol 12 (5) ◽  
pp. 612-623 ◽  
Author(s):  
Alicja Gackowska ◽  
Maciej Przybyłek ◽  
Waldemar Studziński ◽  
Jerzy Gaca
Keyword(s):  
Experimental Studies ◽  
Fukui Function ◽  
Mass Spectrometric ◽  
Theoretical Studies ◽  
Reaction Products ◽  
Reactivity Indices ◽  
Mass Spectrometric Detector ◽  
Methoxycinnamic Acid ◽  
Experimental And Theoretical Studies ◽  
Dft And Mp2 Calculations

Abstract2-Ethylhexyl 4-methoxycinnamate (EHMC) is one of the most commonly used sunscreen ingredient. In this study we investigated photodegradation of EHMC in the presence of such common oxidizing and chlorinating systems as H2O2, H2O2/HCl, H2O2/UV, and H2O2/HCl/UV. Reaction products were detected by gas chromatography with a mass spectrometric detector (GC-MS). As a result of experimental studies chloro-substituted 4-methoxycinnamic acid (4-MCA), 4-methoxybenzaldehyde (4-MBA) and 4-methoxyphenol (4-MP) were identified. Experimental studies were enriched with DFT and MP2 calculations. We found that reactions of 4-MCA, 4-MBA and 4-MP with Cl2 and HOCl were in all cases thermodynamically favorable. However, reactivity indices provide a better explanation of the formation of particular chloroorganic compounds. Generally, those isomeric forms of mono- and dichlorinated compounds which exhibits the highest hardness were identified. Nucleophilicity of the chloroorganic compounds precursors were examined by means of the Fukui function.

scholarly journals Data processing method for experimental studies of deformation in a rock sample under uniaxial compression

2019 ◽  
Vol 129 ◽  
pp. 01018
Author(s):  
Andrei Golosov ◽  
Olga Lubimova ◽  
Mikhail Zhevora ◽  
Vladislava Markevich ◽  
Vladimir Siskov
Keyword(s):  
Rock Sample ◽  
Experimental Studies ◽  
Main Element ◽  
Theoretical Studies ◽  
Dynamic Changes ◽  
New Approach ◽  
Rock Samples ◽  
Data Processing Method ◽  
Patterns Of Behavior ◽  
Experimental And Theoretical Studies

As a result of experimental and theoretical studies, the patterns of behavior of rocks in a condition close to destructive are the focal nature of the preparation of macrocracking, which allowed us to include the mesocrack structure of the material, which is the main element in the preparation of macrocracking. Differences in this new approach to mathematical modeling will let adequately describe dissipative mesocrack structures of various hierarchical levels of geodesy, predict dynamic changes, structures and mechanical properties of both rock samples and massif, which also lead to resource-intensive experimental studies. In this paper, with usage of the methods of cluster, factor, and statistical analysis, we set the task of processing the data of experimental studies of the laws of deformation and preparing macro-fracture of rock samples by various methods, including acoustic and deformation observations.

Experimental and Theoretical Studies of Two-Dimensional Fixed-Type Cavities

1975 ◽  
Vol 97 (4) ◽  
pp. 515-521 ◽  
Author(s):  
R. A. Furness ◽  
S. P. Hutton
Keyword(s):  
Potential Flow ◽  
Reasonable Agreement ◽  
Experimental Studies ◽  
Liquid Jet ◽  
Theoretical Studies ◽  
Two Dimensional ◽  
Nozzle Throat ◽  
Jet Behavior ◽  
Fixed Type ◽  
Experimental And Theoretical Studies

Theoretical and experimental studies have been made of the growth and collapse of fixed cavities in a two-dimensional convergent-divergent nozzle. In this particular configuration an important feature was a re-entrant liquid jet which invaded the growing cavity from the downstream end, travelling upstream along the wall and interrupting the cavity when it reached the nozzle throat. A simple two-dimensional unsteady potential flow theory, developed to model the cycle, gave reasonable agreement with cinephotography and predicted the jet behavior. Because vaporization was neglected the theory overestimated the speed of the cycle.

scholarly journals Determination of wave vectors using the phase differencing method

2013 ◽  
Vol 31 (9) ◽  
pp. 1611-1617 ◽  
Author(s):  
S. N. Walker ◽  
I. Moiseenko
Keyword(s):  
Wave Packet ◽  
Correlation Length ◽  
Coherence Length ◽  
Low Frequency ◽  
Plasma Waves ◽  
Mhd Waves ◽  
Space Plasmas ◽  
The Waves ◽  
Theoretical Results

Abstract. Due to the collisionless nature of space plasmas, plasma waves play an important role in the redistribution of energy between the various particle populations in many regions of geospace. In order to fully comprehend such mechanisms it is necessary to characterise the nature of the waves present. This involves the determination of properties such as wave vector k. There are a number of methods used to calculate k based on the multipoint measurements that are now available. These methods rely on the fact that the same wave packet is simultaneously observed at two or more locations whose separation is small in comparison to the correlation length of the wave packet. This limitation restricts the analysis to low frequency (MHD) waves. In this paper we propose an extension to the phase differencing method to enable the correlation of measurements that were not made simultaneously but differ temporally by a number of wave periods. The method is illustrated using measurements of magnetosonic waves from the Cluster STAFF search coil magnetometer. It is shown that it is possible to identify wave packets whose coherence length is much less than the separation between the measurement locations. The resulting dispersion is found to agree with theoretical results.

scholarly journals STUDIES OF PHOTOIONIZATION PROCESSES OF NITROGEN-LIKE O+ION USINGTHE SCREENING CONSTANT BY UNIT NUCLEAR CHARGEMETHOD

2021 ◽  
Vol 9 (09) ◽  
pp. 977-985
Author(s):  
Babou Diop ◽  
◽  
Abdou Diouf ◽  
Youssou Gning ◽  
Maurice Faye ◽  
...  
Keyword(s):  
Experimental Data ◽  
Metastable State ◽  
Effective Charge ◽  
Nuclear Charge ◽  
Theoretical Studies ◽  
Rydberg Series ◽  
Screening Constant ◽  
Semi Empirical ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

In this present work, we have calculated the energies positions of the 2s22p2(1D)nd2P, 2s22p2(1D)nd2S, 2s22p2(1D)ns 2D, 2s22p2(1S)nd2D and 2s2p3(3P)np2D Rydberg series in the photoionization spectra from the 2P° metastable state of the O+ ion. Calculations were performed up to n = 40 applyingthe Screening Constant by Unit Nuclear Charge (SCUNC) via its semi empirical formalism. The quantum defect and the effective charge are also calculated.The results agree within 98% to Aguilars experimental data, and with Sows theoretical results to within 99%. These data can be a useful guideline for future experimental and theoretical studies.

On the Magic Character of Al6Au-

2007 ◽  
Vol 72 (2) ◽  
pp. 185-196 ◽  
Author(s):  
Michele L. Kimble ◽  
Albert W. Castleman ◽  
Jose U. Reveles ◽  
Shiv N. Khanna
Keyword(s):  
Flow Reactor ◽  
Experimental Studies ◽  
Gold Clusters ◽  
Laser Vaporization ◽  
Theoretical Studies ◽  
Triangular Face ◽  
Stable Species ◽  
The Stability ◽  
Experimental And Theoretical Studies ◽  
Homo Lumo

Joint experimental and theoretical studies have been carried out to identify the stability of aluminum gold clusters. The experimental studies where the AlnAu- clusters are generated via laser vaporization in a flow reactor and subsequently reacted with oxygen indicate that Al6Au- is an exceptionally stable species that is not only resistant to etching by oxygen but also grows in intensity when AlnAu- clusters are exposed to oxygen. Theoretical studies indicate that the six aluminum atoms in Al6Au- form an octahedron and that the Au atom occupies a hollow site above the triangular face of the octahedron. It is shown that it takes much larger energy to remove an Al or a Au atom compared to that for neighboring sizes, and this accounts for its resistance to oxygen. The special stability is rooted in the electronic spectrum that is marked by a large HOMO-LUMO gap of 1.38 eV, and the system is best described as a nearly free electron gas of 20 electrons.

Experimental Studies on the Bonding Failure between CFRP and Concrete in RC Two-Way Slabs Strengthened with CFRP Strips

2012 ◽  
Vol 166-169 ◽  
pp. 1530-1533
Author(s):  
Wen Bin Sun ◽  
Jing Zhao ◽  
Yang Jiang
Keyword(s):  
Failure Modes ◽  
Experimental Studies ◽  
Theoretical Studies ◽  
High Shear ◽  
Bending Moments ◽  
Shear Forces ◽  
Bonding Failure ◽  
Externally Bonded ◽  
Cfrp Strip ◽  
Experimental And Theoretical Studies

It is well known that the bonding failure between concrete and externally bonded CFRP strips sets in where high shear forces and high bending moments occur. Despite this knowledge, experimental and theoretical studies had been exclusively focused on the bonding failure modes at the end of the CFRP-strip. This paper deals with strengthening of RC two-way slabs with CFRP strips bonded to the tensile face. It focuses on the bonding failure by dealing with an experimental study. The CFRP-strips strengthened slab test presents a failure mode with debonding of the external CFRP strips from the slab.

Experimental and theoretical studies on the nucleofugality ratio in the aminolysis reactions of O-(4-cyanophenyl) O-(3-nitrophenyl) thionocarbonate with amines in aqueous ethanol

2017 ◽  
Vol 41 (18) ◽  
pp. 9954-9962 ◽  
Author(s):  
Rodrigo Montecinos ◽  
Margarita E. Aliaga ◽  
Paulina Pavez ◽  
José G. Santos
Keyword(s):  
Aqueous Ethanol ◽  
Water Molecules ◽  
Theoretical Studies ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

The title thionocarbonate reacts with amines to form 4-cyanophenol and 3-nitrophenol in a 1.5 : 1 ratio. Theoretical results show that the products ratio depends on the microsolvation of the water molecules.

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