Ultra-relativistic electrostatic Bernstein waves

A new general form of the dispersion relation for electrostatic Bernstein waves in ultra-relativistic pair plasmas, characterized by a−1 = kBT/(mec2)  1, is derived in this paper. The parameter Sp = aΩ0/ωp, where Ω0 is the rest cyclotron frequency for electrons or positrons and ωp is the electron (or positron) plasma frequency, plays a crucial role in characterizing these waves. In particular, Sp has a restricted range for permitted wave solutions; this range is effectively unlimited for classical plasmas, but is significant for the ultra-relativistic case. The characterization of these waves is applied in particular to the presence of such plasmas in pulsar atmospheres

A Fragment of Ophiolite Assemblage of Kasargi Lake Area: East-Urals Megazone, Northern Part of the Southern Urals

Приведено описание пород офиолитовой ассоциации, обнажающейся на восточном берегу озера Касарги. В составе ассоциации диагностированы серпентинизированные породы дунит-гарцбургитового комплекса, имеющие реститовую природу, и шлировоолосчатые габброиды с многочисленными более поздними дайками диабазов и порфировидных габбро. По геохимическим характеристикам мафиты и ультрамафиты Касаргинского массива близки к аналогичным породам из областей задугового спрединга.The results of study of rocks of ophiolite assemblage exposed on the east coast of Kasargi Lake are presented. The ophiolite assemblage is formed with the serpentinised ultramafic rocks of dunite-harzburgite association, which are residual and the shlirenbanded gabbros with a number of later dikes of diabases and porphiritic gabbros. The chemical content of mafic and ultramafic rocks of Kasargi massif shows that they are likely the equivalent rocks encountered within the backarc spreading ridges

Topological gravity on plumbed V-cobordisms

An ensemble of cosmological models based on generalized BF-theory is constructed where the role of vacuum (zero-level) coupling constants is played by topologically invariant rational intersection forms (cosmological-constant matrices) of 4-dimensional plumbed V-cobordisms which are interpreted as Euclidean spacetime regions. For these regions describing topology changes, the rational and integer intersection matrices are calculated. A relation is found between the hierarchy of certain elements of these matrices and the hierarchy of coupling constants of the universal (low-energy) interactions. PACS numbers: 0420G, 0240, 0460Comment: 29 page

Compositional Variation of Chrome Spinels in the Ore-bearing Zones of the Kraka Ophiolite and the Chromitite Origin

The article considers a chemical variation of accessory and ore-forming chrome spinels from the Kraka ultramafic massif at the different scales, from the deposit to the thin section. A correlation analysis of compositional and structural features of ultramafic rocks and ores was performed. The ultramafic rocks and chromitites in the studied massif show the distinct deformation structures and tectonite olivine fabric. A typical chemical gap (i.e. Cr#=Cr/(Cr+Al)) was observed between peridotite, on the one hand, and dunite and chromitite, on the other hand, on the scale of deposits and ore-bearing zones. The location and size of this gap depend on the type of deposit. The gap becomes wider from the disseminated tabular bodies to the typical podiform ones. It has been found that in the thin initial dunite veinlets in peridotite the chrome spinels chemistry changes gradually and there is no Cr# gap between peridotite and dunite. The dunite venlets show a strong olivine fabric, which is an evidence of their high-temperature plastic flow origin. It has been revealed that new chrome spinel grains previously formed as rods or needles and then coarsened. We explained this observation as the result of impurity segregation, coalescence and spheroidization induced by the plastic deformation of olivine. It is inferred that a solid crystal flow is the main requirement for the dunite and chromitite body formation in the Kraka ophiolite massif. In the solid stream, the mineral phase separation takes place. For example, olivine and orthopyroxene grains of parental peridotite separate from one another, and weaker (more mobile) olivine grains form dunite bodies in which chromitite appears as a result of impurity segregation

Compositional Variation of Chrome Spinels in the Ore-bearing Zones of the Kraka Ophiolite and the Chromitite Origin

The article considers a chemical variation of accessory and ore-forming chrome spinels from the Kraka ultramafic massif at the different scales, from the deposit to the thin section. A correlation analysis of compositional and structural features of ultramafic rocks and ores was performed. The ultramafic rocks and chromitites in the studied massif show the distinct deformation structures and tectonite olivine fabric. A typical chemical gap (i.e. Cr#=Cr/(Cr+Al)) was observed between peridotite, on the one hand, and dunite and chromitite, on the other hand, on the scale of deposits and ore-bearing zones. The location and size of this gap depend on the type of deposit. The gap becomes wider from the disseminated tabular bodies to the typical podiform ones. It has been found that in the thin initial dunite veinlets in peridotite the chrome spinels chemistry changes gradually and there is no Cr# gap between peridotite and dunite. The dunite venlets show a strong olivine fabric, which is an evidence of their high-temperature plastic flow origin. It has been revealed that new chrome spinel grains previously formed as rods or needles and then coarsened. We explained this observation as the result of impurity segregation, coalescence and spheroidization induced by the plastic deformation of olivine. It is inferred that a solid crystal flow is the main requirement for the dunite and chromitite body formation in the Kraka ophiolite massif. In the solid stream, the mineral phase separation takes place. For example, olivine and orthopyroxene grains of parental peridotite separate from one another, and weaker (more mobile) olivine grains form dunite bodies in which chromitite appears as a result of impurity segregation.The article considers a chemical variation of accessory and ore-forming chrome spinels from the Kraka ultramafic massif at the different scales, from the deposit to the thin section. A correlation analysis of compositional and structural features of ultramafic rocks and ores was performed. The ultramafic rocks and chromitites in the studied massif show the distinct deformation structures and tectonite olivine fabric. A typical chemical gap (i.e. Cr#=Cr/(Cr+Al)) was observed between peridotite, on the one hand, and dunite and chromitite, on the other hand, on the scale of deposits and ore-bearing zones. The location and size of this gap depend on the type of deposit. The gap becomes wider from the disseminated tabular bodies to the typical podiform ones. It has been found that in the thin initial dunite veinlets in peridotite the chrome spinels chemistry changes gradually and there is no Cr# gap between peridotite and dunite. The dunite venlets show a strong olivine fabric, which is an evidence of their high-temperature plastic flow origin. It has been revealed that new chrome spinel grains previously formed as rods or needles and then coarsened. We explained this observation as the result of impurity segregation, coalescence and spheroidization induced by the plastic deformation of olivine. It is inferred that a solid crystal flow is the main requirement for the dunite and chromitite body formation in the Kraka ophiolite massif. In the solid stream, the mineral phase separation takes place. For example, olivine and orthopyroxene grains of parental peridotite separate from one another, and weaker (more mobile) olivine grains form dunite bodies in which chromitite appears as a result of impurity segregation

Nurali Ophiolite Massif (the Southern Urals): Geological, Structural, and Mineralogical Features

An overview of a geological structure of Nurali massif is presented. Compositional data of ultramafic rocks from mantle section and transitional mantle-crust assemblages, and chemistry of accessory and ore-forming Cr spinels are examined. We showed that ultramafic rocks from mantle section (spinel a spinel-plagioclase peridotites, harzburgites, dunites) are the tectonites. They have a strong predominantly optical orientation of rock-forming olivine due to a plastic flow of rocks. We presented different points of view on the mantle-crust assemblage origin, which composed by wehrlites, clinopyroxenites, vebsterites, dunites and melanocratic gneiss-like gabbro, and described two PGE-occurrences in the chromitites of this ophiolite section unit. This paper is based on a guidebook of an International field trip to Nurali massif as a part of conference “Magmatism of the Earth and related deposits of strategic metals” held in 2017 Augus

Nurali Ophiolite Massif (the Southern Urals): Geological, Structural, and Mineralogical Features

An overview of a geological structure of Nurali massif is presented. Compositional data of ultramafic rocks from mantle section and transitional mantle-crust assemblages, and chemistry of accessory and ore-forming Cr spinels are examined. We showed that ultramafic rocks from mantle section (spinel a spinel-plagioclase peridotites, harzburgites, dunites) are the tectonites. They have a strong predominantly optical orientation of rock-forming olivine due to a plastic flow of rocks. We presented different points of view on the mantle-crust assemblage origin, which composed by wehrlites, clinopyroxenites, vebsterites, dunites and melanocratic gneiss-like gabbro, and described two PGE-occurrences in the chromitites of this ophiolite section unit. This paper is based on a guidebook of an International field trip to Nurali massif as a part of conference “Magmatism of the Earth and related deposits of strategic metals” held in 2017 AugustAn overview of a geological structure of Nurali massif is presented. Compositional data of ultramafic rocks from mantle section and transitional mantle-crust assemblages, and chemistry of accessory and ore-forming Cr spinels are examined. We showed that ultramafic rocks from mantle section (spinel a spinel-plagioclase peridotites, harzburgites, dunites) are the tectonites. They have a strong predominantly optical orientation of rock-forming olivine due to a plastic flow of rocks. We presented different points of view on the mantle-crust assemblage origin, which composed by wehrlites, clinopyroxenites, vebsterites, dunites and melanocratic gneiss-like gabbro, and described two PGE-occurrences in the chromitites of this ophiolite section unit. This paper is based on a guidebook of an International field trip to Nurali massif as a part of conference “Magmatism of the Earth and related deposits of strategic metals” held in 2017 August

Properties of equations of the continuous Toda type

We study a modified version of an equation of the continuous Toda type in 1+1 dimensions. This equation contains a friction-like term which can be switched off by annihilating a free parameter \ep. We apply the prolongation method, the symmetry and the approximate symmetry approach. This strategy allows us to get insight into both the equations for \ep =0 and \ep \ne 0, whose properties arising in the above frameworks are mutually compared. For \ep =0, the related prolongation equations are solved by means of certain series expansions which lead to an infinite- dimensional Lie algebra. Furthermore, using a realization of the Lie algebra of the Euclidean group $E_{2}$, a connection is shown between the continuous Toda equation and a linear wave equation which resembles a special case of a three-dimensional wave equation that occurs in a generalized Gibbons-Hawking ansatz \cite{lebrun}. Nontrivial solutions to the wave equation expressed in terms of Bessel functions are determined. For \ep\,\ne\,0, we obtain a finite-dimensional Lie algebra with four elements. A matrix representation of this algebra yields solutions of the modified continuous Toda equation associated with a reduced form of a perturbative Liouville equation. This result coincides with that achieved in the context of the approximate symmetry approach. Example of exact solutions are also provided. In particular, the inverse of the exponential-integral function turns out to be defined by the reduced differential equation coming from a linear combination of the time and space translations. Finally, a Lie algebra characterizing the approximate symmetries is discussed.Comment: LaTex file, 27 page

Investigation of the influence of the length of the intermediate magnetic circuit on the characteristics of magnetic gripper for robotic complexes of the mining industry

The analysis of the existing systems of mechanical grippers of various operating principles and operating environments, in the design of which both soft and hard magnetic materials are executed. The characteristics of existing prototypes are shown and the results of our own research are presented. The article presents a study of the effect of the intermediate magnetic circuit length on the characteristics of magnetic gripper, the principle of which is based on the control of the field of a permanent magnet. The gripper based on this principle of action does not require constant energy expenditures to maintain both on and off states. The description of the magnetic gripper design and the design of the test bench is given, as well as the results of a series of experiments to determine the strength of the release of the gripper at different lengths of the magnetic circuit in the on and off states, followed by statistical processing of the data. The intervals of the ranges in which with a high degree of probability there will be a value of the gripping disengagement force for various lengths of the intermediate magnetic circuit are identified. The nature of the distribution of a random variable, which is the force of decoupling of the gripper, is determined. The dependences of the gripper decoupling force on the length of the intermediate magnetic circuit for each of the gripper states are constructed. It has been established that a decrease in the length of the intermediate magnetic circuit is the cause of a decrease in the gripping adhesion force. Plots of the dependence of the gripper decoupling force were constructed using the modes of the force values varieties to visually display the experimental results. The maximum adhesion force of magnetic pickup – 9.5 kg – was achieved with an intermediate magnetic core length of 50 mm, the minimum with a length of 25 mm – 5.6 kg

A class of nonlinear wave equations containing the continuous Toda case

We consider a nonlinear field equation which can be derived from a binomial lattice as a continuous limit. This equation, containing a perturbative friction-like term and a free parameter $\gamma$, reproduces the Toda case (in absence of the friction-like term) and other equations of physical interest, by choosing particular values of $\gamma$. We apply the symmetry and the approximate symmetry approach, and the prolongation technique. Our main purpose is to check the limits of validity of different analytical methods in the study of nonlinear field equations. We show that the equation under investigation with the friction-like term is characterized by a finite-dimensional Lie algebra admitting a realization in terms of boson annhilation and creation operators. In absence of the friction-like term, the equation is linearized and connected with equations of the Bessel type. Examples of exact solutions are displayed, and the algebraic structure of the equation is discussed.Comment: Latex file + [equations.sty], 22 p