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Nitrogen and carbon contents of fine roots were studied for 92 alpine plant species in the Northwest Caucasus. Nitrogen content ranged from 0.43% (Bromus variegatus) to 3.75% (Corydalis conorhiza) with mean value 1.3%. Carbon content ranged from 40.3% (Corydalis conorhiza) to 51.7% (Empetrum nigrum) with mean value 43.4%. C:N ratio was found to be 34:1 which is higher than the worldwide mean. Eudicot's roots had higher N concentration (1.37 +/- 0.07) than monocot's ones (0.95 +/- 0.09). Among the life forms, carbon content increased in the following order: geophytes < hemicriptophytes < chamaephytes. Specific root length positively correlated with nitrogen root content and negatively--with carbon root content. Species with larger leaves and higher specific root area had more nitrogen and less carbon in roots in comparison with species with small leaves. There were positive correlations between leaf and root nitrogen, as well as carbon, contents. Regrowth rate; seed size, aboveground biomass, and vegetation mobility were not related with root nitrogen content. Our results corroborate the poor and rich soil adaptation syndromes. Species of competitive and ruderal (sensu Grime) strategies are more typical for alpine meadows and snow bed communities. They had higher nitrogen contents in leaves and roots, larger leaves with higher water content and higher rate of seed production. On the other hand, stress-tolerant plants had higher carbon and less nitrogen concentrations in their roots and leaves, smaller leaves and specific leaf area.

Nitrogen and carbon contents of fine roots were studied for 92 alpine plant species in the Northwest Caucasus. Nitrogen content ranged from 0.43% (Bromus variegatus) to 3.75% (Corydalis conorhiza) with mean value 1.3%. Carbon content ranged from 40.3% (Corydalis conorhiza) to 51.7% (Empetrum nigrum) with mean value 43.4%. C:N ratio was found to be 34:1 which is higher than the worldwide mean. Eudicot's roots had higher N concentration (1.37 +/- 0.07) than monocot's ones (0.95 +/- 0.09). Among the life forms, carbon content increased in the following order: geophytes < hemicriptophytes < chamaephytes. Specific root length positively correlated with nitrogen root content and negatively--with carbon root content. Species with larger leaves and higher specific root area had more nitrogen and less carbon in roots in comparison with species with small leaves. There were positive correlations between leaf and root nitrogen, as well as carbon, contents. Regrowth rate; seed size, aboveground biomass, and vegetation mobility were not related with root nitrogen content. Our results corroborate the poor and rich soil adaptation syndromes. Species of competitive and ruderal (sensu Grime) strategies are more typical for alpine meadows and snow bed communities. They had higher nitrogen contents in leaves and roots, larger leaves with higher water content and higher rate of seed production. On the other hand, stress-tolerant plants had higher carbon and less nitrogen concentrations in their roots and leaves, smaller leaves and specific leaf area.

The presence of higher current harmonics has a negative impact on the efficiency and reliability of the elements of network. Higher current harmonics can lead to significant increases of resistance, voltage drop and active losses in busbar, also to decreasing network power factor. Existing engineering techniques can’t provide a reliable calculation of the parameters of busbars at higher current harmonics influences. Therefore, the aim of the work is to develop a new approach of parameters determination and the voltage drop estimation in busbar at higher current harmonics influence. Mathematical model of electromagnetic processes in busbar, which takes into account their design features, non-linearity of magnetic and electrophysical properties, proximity effects, surface and external surface effects, was developed and proposed. This model will allow to determinate the components of active and reactive resistances of busbar, voltage drops for each eigenvalue of the amplitude and frequency of current harmonics. Based on field simulation results was obtained the functional dependence in bicubic polynomial form. For effective spectra and amplitudes of higher harmonics, at selecting the corresponding polynomial coefficients, it will allow to determinate the components and the resulting values of voltage drops for an individual busbar’s design without spending time on field simulation. Based on the proposed approach, a method will be developed for the busbar's parameters identification and voltage drop estimation. This will allow effectively define the network configuration, installed capacity of compensating devices, which will provide the reliability of electrical collectors with the declared technical data and etc.

The presence of higher current harmonics has a negative impact on the efficiency and reliability of the elements of network. Higher current harmonics can lead to significant increases of resistance, voltage drop and active losses in busbar, also to decreasing network power factor. Existing engineering techniques can’t provide a reliable calculation of the parameters of busbars at higher current harmonics influences. Therefore, the aim of the work is to develop a new approach of parameters determination and the voltage drop estimation in busbar at higher current harmonics influence. Mathematical model of electromagnetic processes in busbar, which takes into account their design features, non-linearity of magnetic and electrophysical properties, proximity effects, surface and external surface effects, was developed and proposed. This model will allow to determinate the components of active and reactive resistances of busbar, voltage drops for each eigenvalue of the amplitude and frequency of current harmonics. Based on field simulation results was obtained the functional dependence in bicubic polynomial form. For effective spectra and amplitudes of higher harmonics, at selecting the corresponding polynomial coefficients, it will allow to determinate the components and the resulting values of voltage drops for an individual busbar’s design without spending time on field simulation. Based on the proposed approach, a method will be developed for the busbar's parameters identification and voltage drop estimation. This will allow effectively define the network configuration, installed capacity of compensating devices, which will provide the reliability of electrical collectors with the declared technical data and etc.