Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 8 (2001), S. 697-703 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In tight aspect ratio toroidal devices, characteristics of bounded whistler sustained plasma filled resonant cavities are shown to have significant differences as compared to characteristics of cylindrical cavities in helicon plasma sources. In the present article the analytical-numerical treatment of the problem in electronmagnetohydrodynamic regime is based on wave-field computation and modified dispersive properties of wave for toroidal devices. In the limit of tight aspect ratio, the parallel wavelength of the excited whistler becomes comparable to the system dimension and, thus, strong poloidal mode coupling introduces new features to radially bounded whistlers. Smooth transition of toroidal bounded whistler modes towards conventional helicon modes is observed as the major radius increases. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1440-1703
    Keywords: bamboo ; biomass ; carbon budget ; carbon flux ; dry tropics ; production ; savanna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Culm recruitment, standing crop biomass, net production and carbon flux were estimated in mature (5 years after last harvest) and recently harvested bamboo (Dendrocalamus strictus (Roxb.) Nees) savanna sites in the dry tropics. During the 2 study years bamboo shoot recruitment was 1711–3182 and 1432–1510 shoots ha−1 in harvested and mature sites, respectively. Corresponding shoot mortality was 66–93% and 62–69%, respectively. Total biomass was 34.9 t ha−1 at the harvested site and 47.4 t ha−1 at the mature site. Harvesting increased the relative contribution of belowground bamboo biomass. Annual litter input to soil was 2.7 and 5.9 t ha−1 year−1 at the harvested and mature sites, respectively. The bulk of the annual litterfall (78–88%) occurred in the cool dry season (November to February). The mean litter mass on the savanna floor ranged from 3.1 to 3.3 t ha−1; at the harvested site wood litter contributed 70% of the litter mass and at the mature site leaves formed 77% of the litter mass. The mean total net production (TNP) for the two annual cycles was 15.8 t ha−1 year−1 at the harvested site and 19.3 t ha−1 year−1 at the mature site. Nearly half (46–57%) of the TNP was allocated to the belowground parts. Short lived components (leaves and fine roots) contributed about four-fifths of the net production of bamboo. Total carbon storage in the system was 64.4 t ha−1 at the harvested site and 75.4 t ha−1 at the mature site, of which 23–28% was distributed in vegetation, 2% in litter and 70–75% in soil. Annual net carbon deposition was 6.3 and 8.7 t ha−1 year−1 at harvested and mature sites, respectively.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0789
    Keywords: Decomposition ; Immobilization ; Mineralization ; Bamboo savanna ; Litter types ; Lignin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Decomposition and changes in nutrient content of six litter types (leaves, sheaths, roots, twigs, and wood of bamboo, and grass shoots) were studied in nylon net bags for 2 years. The annual weight loss was (% of initial) bamboo leaves 56.5, bamboo sheaths 79.5, bamboo roots 65.8, bamboo twigs 49.6, bamboo wood 31.2, and grass shoots 74.9. Elemental mobility followed the order K〉Na〉C〉P〉Ca〉N in all components except wood. Generally, an initial increase was followed by a consistent decrease in the contents of N (leaves), P (leaves, roots, wood) and Ca (leaves, roots, grass), and Na (wood). Most of the nutrients were immobilized in the rainy season. C and K contents showed a constant decrease throughout the decomposition period. Materials with a greater C:N ratio (〉50) tended to accumulate more nutrients and retain them for longer, except for the bamboo twigs. The critical C:N ratio (at which a net release of N occured) for the leaf material was 25. Litter components with more initial N (sheaths) showed greater weight loss than those with less N (leaves, twigs, and wood). Overall, N and P were lost at the slowest rates while C and K were lost at faster rates. Initial lignin, lignin: N, C:N and C concentrations had a better predictive value for annual weight loss and nutrient release in bivariate relationships. A combination of the initial lignin value and the C: N ratio explained 93% of the variation in annual weight loss. A significant relationship was also observed between the annual weight loss rate and the nutrient mineralization/release rate.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0789
    Keywords: Key words Litterfall ; Litter decomposition ; Nutrient immobilization ; Nutrient mineralization ; Mine spoil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Litterfall, leaf litter decomposition and N and P release were studied in four tree species (Dalbergia sissoo, Azadirachta indica, Pongamia pinnata and Shorea robusta) planted on a mine spoil habitat. Annual litterfall varied from 1220 kg ha–1 in the S. robusta stand to 3620 kg ha–1 in the A. indica stand. The fast-growing species A. indica and D. sissoo exhibited higher litter production in comparison to the other two slow-growing species. The total N returned to the soil through litterfall ranged from 8.6 kg ha–1 year–1 in the S. robusta stand to 36.5 kg ha–1 year–1 in the D. sissoo stand. The annual percent leaf litter mass loss was distinctly greater in A. indica (73%) and D. sissoo (69%) in comparison to P. pinatta (59%) and S. robusta (47%). The mean relative decomposition rates of leaf litter material were maximum in the rainy season and minimum in summer. Rainfall and its associated variables exhibited greater control over litter docomposition than temperature. Lignin and water-soluble compounds were better predictors of annual mass loss rates accounting for 90% variability. Mass loss was positively correlated with N and P mineralization rates. Lignin was the best predictor of annual N and P mineralization rates. Nutrient release pattern differed; constant release occurred in A. indica, initial release followed by delayed immobilization and release occurred in D. sissoo and P. pinnata, and initial immobilization followed by gradual release was noticed in S. robusta. A. indica and D. sissoo, showing high litterfall and rapid litter decomposition rate, hold promise for the rehabilitation of nutrient-poor coal mine spoils. On the other hand, S. robusta with less litterfall and a slow decomposition rate may prove disadvantageous.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...