Calculating the Parameters of an Inductive Short Circuit Current Limiter with a Superconducting Shield

An inductive short circuit current limiter with a superconducting shield and its operation under normal and emergency conditions are analyzed. A method for calculating its key parameters is proposed

On leaders and condensates in a growing network

The Bianconi-Barabasi model of a growing network is revisited. This model, defined by a preferential attachment rule involving both the degrees of the nodes and their intrinsic fitnesses, has the fundamental property to undergo a phase transition to a condensed phase below some finite critical temperature, for an appropriate choice of the distribution of fitnesses. At high temperature it exhibits a crossover to the Barabasi-Albert model, and at low temperature, where the fitness landscape becomes very rugged, a crossover to the recently introduced record-driven growth process. We first present an analysis of the history of leaders, the leader being defined as the node with largest degree at a given time. In the generic finite-temperature regime, new leaders appear endlessly, albeit on a doubly logarithmic time scale, i.e., extremely slowly. We then give a novel picture for the dynamics in the condensed phase. The latter is characterized by an infinite hierarchy of condensates, whose sizes are non-self-averaging and keep fluctuating forever.Comment: 29 pages, 13 figures, 3 tables. A few minor change

Primordial magnetic fields and nonlinear electrodynamics

The creation of large scale magnetic fields is studied in an inflationary universe where electrodynamics is assumed to be nonlinear. After inflation ends electrodynamics becomes linear and thus the description of reheating and the subsequent radiation dominated stage are unaltered. The nonlinear regime of electrodynamics is described by lagrangians having a power law dependence on one of the invariants of the electromagnetic field. It is found that there is a range of parameters for which primordial magnetic fields of cosmologically interesting strengths can be created.Comment: 21 pages, 3 figure

Feasibility of a Small, Rapid Optical-to-IR Response, Next Generation Gamma Ray Burst Mission

We present motivations for and study feasibility of a small, rapid optical to IR response gamma ray burst (GRB) space observatory. By analyzing existing GRB data, we give realistic detection rates for X-ray and optical/IR instruments of modest size under actual flight conditions. Given new capabilities of fast optical/IR response (about 1 s to target) and simultaneous multi-band imaging, such an observatory can have a reasonable event rate, likely leading to new science. Requiring a Swift-like orbit, duty cycle, and observing constraints, a Swift-BAT scaled down to 190 square cm of detector area would still detect and locate about 27 GRB per yr. for a trigger threshold of 6.5 sigma. About 23 percent of X-ray located GRB would be detected optically for a 10 cm diameter instrument (about 6 per yr. for the 6.5 sigma X-ray trigger).Comment: Elaborated text version of a poster presented at 2012 Malaga/Marbella symposiu

ОСОБЛИВОСТІ РОБОТИ НАДПРОВІДНОГО ОБМЕЖУВАЧА СТРУМУ ПРИ РАПТОВОМУ КОРОТКОМУ ЗАМИКАННІ

In the article the fault current limiter of inductive type with high-temperature superconducting coil and screen is considered. Main features of transient at occurrence of short circuit are analyzed.В статье рассмотрен ограничитель тока короткого замыкания индуктивного типа с высокотемпературными сверхпроводящими обмоткой и экраном. Проанализированы основные особенности переходного процесса при возникновении тока короткого замыкания.У статті розглянуто обмежувач струму короткого замикання індуктивного типу з високотемпературними надпровідними обмоткою та екраном. Проаналізовано основні особливості перехідного процесу при виникненні струму короткого замикання

Restricted sum formula of alternating Euler sums

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A record-driven growth process

We introduce a novel stochastic growth process, the record-driven growth process, which originates from the analysis of a class of growing networks in a universal limiting regime. Nodes are added one by one to a network, each node possessing a quality. The new incoming node connects to the preexisting node with best quality, that is, with record value for the quality. The emergent structure is that of a growing network, where groups are formed around record nodes (nodes endowed with the best intrinsic qualities). Special emphasis is put on the statistics of leaders (nodes whose degrees are the largest). The asymptotic probability for a node to be a leader is equal to the Golomb-Dickman constant omega=0.624329... which arises in problems of combinatorical nature. This outcome solves the problem of the determination of the record breaking rate for the sequence of correlated inter-record intervals. The process exhibits temporal self-similarity in the late-time regime. Connections with the statistics of the cycles of random permutations, the statistical properties of randomly broken intervals, and the Kesten variable are given.Comment: 30 pages,5 figures. Minor update

RF-Magnetron sputtering of silicon carbide and silicon nitride films for solar cells

RF-magnetron nonreactive sputtering method from solid-phase target in argon atmosphere was used for obtaining thin silicon carbide and silicon nitride films, that are used for constructing solar cells based on substrates of single crystal silicon of p-typ

Natural Chaotic Inflation in Supergravity

We propose a chaotic inflation model in supergravity. In the model the K\"ahler potential has a Nambu-Goldstone-like shift symmetry of the inflaton chiral multiplet which ensures the flatness of the inflaton potential beyond the Planck scale. We show that the chaotic inflation naturally takes place by introducing a small breaking term of the shift symmetry in the superpotential. This may open a new branch of model building for inflationary universe in the framework of supergravity.Comment: Some typos are corrected. To appear in Phys. Rev. Let