Search Results (4)

There are numerous instabilities present in charged particle beams that undergo exponential growth and reach saturation. In various applications, such as free-electron lasers or micro-bunching light sources, achieving saturation is desirable. Conversely, there are applications where these instabilities are utilized as linear broad-band amplifiers for signals embedded in the charged beam. In the latter scenario, the saturation of an instability induces non-linear distortions in the imprinted signal, thereby limiting the useful range of such amplifiers. Accurate evaluation of these instabilities necessitates a complete and comprehensive modeling approach that includes shot noise within the beam. Unfortunately, such modeling is not always feasible or practical. In this paper, we introduce a methodology utilizing the frequency and bandwidth of the instability as key parameters. Through this, we derive an estimation for the range of linear instability growth. Our derivation is conducted in a model-independent manner, making it applicable to a broad spectrum of instabilities. To validate our approach, we employ established and thoroughly benchmarked simulations with a free electron laser (FEL) code as well as self-consistent 3-dimensional simulation of plasma-cascade instability using code SPACE. Full article

The article deals with the optimal control of the positional electric drive of the stator element of a segment-type wind turbine. The calculation options charts current in the assumption of the minimum energy consumption and the implementation of line chart current using the phenomenon of capacitor discharge. The analysis of the implementation is expressed in a jump-like change in current and a triangular graph of the speed change. This article deals with small capacity synchronous wind turbine generators with a segment type stator. These units have the possibility of intentionally changing the air gap between the rotor and stator. This allows: (1) Reduce the starting torque on the rotor shaft, which will allow the rotor to pick up at low wind speeds. (2) Equivalent to change of air gap in this case is change of excitation of synchronous generators. Thus, the purpose of the article is to consider a method of excitation of generators in a segmented design, by controlling the gap with the electric drive, while providing control should be carried out with minimal losses. Full article

Hydrogen generation rate is one of the most important parameters which must be considered for the development of engineering solutions in the field of hydrogen energy applications. In this paper, the kinetics of hydrogen generation from oxidation of hydrogenated porous silicon nanopowders in water are analyzed in detail. The splitting of the Si-H bonds of the nanopowders and water molecules during the oxidation reaction results in powerful hydrogen generation. The described technology is shown to be perfectly tunable and allows us to manage the kinetics by: (i) varying size distribution and porosity of silicon nanoparticles; (ii) chemical composition of oxidizing solutions; (iii) ambient temperature. In particular, hydrogen release below 0 °C is one of the significant advantages of such a technological way of performing hydrogen generation. Full article

Presently, there is a paradoxical situation in the global energy market related to a gap between the image of hydrocarbon resources (HCR) and their real value for the economy. On the one hand, we face an increase in expected HCR production and consumption volumes, both in the short and long term. On the other hand, we see the formation of the image of HCR and associated technologies as an unacceptable option, without enough attention to the differences in fuels and the ways of their usage. Due to this, it seems necessary to take a step back to review the vitality of such a political line. This article highlights an alternative point of view with regard to energy development prospects. The purpose of this article is to analyse the consistency of criticism towards HCR based on exploration of scientific literature, analytical documents of international corporations and energy companies as well as critical assessment of technologies offered for the HCR substitution. The analysis showed that: (1) it is impossible to substitute the majority of HCR with alternative power resources in the near term, (2) it is essential that the criticism of energy companies with regard to their responsibility for climate change should lead not to destruction of the industry but to the search of sustainable means for its development, (3) the strategic benchmarks of oil and coal industries should shift towards chemical production, but their significance should not be downgraded for the energy sector, (4) liquified natural gas (LNG) is an independent industry with the highest expansion potential in global markets in the coming years as compared to alternative energy options, and (5) Russia possesses a huge potential for the development of the gas industry, and particularly LNG, that will be unlocked if timely measures on higher efficiency of the state regulation system are implemented. Full article