Упрощенный расчет максимальных тяжений проводов на двух стадиях их движения при коротком замыкании

The paper contains formulae of the simplified calculation of maximum conductor tension at stages of their movement during short circuit. Assurance estimation of the simplified calculation is done on the basis of the experimental data and calculative experiment. Correction factors for higher accuracy of the simplified calculation are proposed in the paper.Получены формулы упрощенного расчета максимальных тяжений в проводах на двух стадиях их движения при коротком замыкании. Выполнена оценка достоверности упрощенного расчета с использованием опытных данных и вычислительного эксперимента. Предложены поправочные коэффициенты для повышения точности упрощенного расчета

EcoVeg: a new approach to vegetation description and classification

A vegetation classification approach is needed that can describe the diversity of terrestrial ecosystems and their transformations over large time frames, span the full range of spatial and geographic scales across the globe, and provide knowledge of reference conditions and current states of ecosystems required to make decisions about conservation and resource management. We summarize the scientific basis for EcoVeg, a physiognomic-floristic-ecological classification approach that applies to existing vegetation, both cultural (planted and dominated by human processes) and natural (spontaneously formed and dominated by nonhuman ecological processes). The classification is based on a set of vegetation criteria, including physiognomy (growth forms, structure) and floristics (compositional similarity and characteristic species combinations), in conjunction with ecological characteristics, including site factors, disturbance, bioclimate, and biogeography. For natural vegetation, the rationale for the upper levels (formation types) is based on the relation between global-scale vegetation patterns and macroclimate, hydrology, and substrate. The rationale for the middle levels is based on scaling from regional formations (divisions) to regional floristic-physiognomic types (macrogroup and group) that respond to meso-scale biogeographic, climatic, disturbance, and site factors. Finally, the lower levels (alliance and association) are defined by detailed floristic composition that responds to local to regional topo-edaphic and disturbance gradients. For cultural vegetation, the rationale is similar, but types are based on distinctive vegetation physiognomy and floristics that reflect human activities. The hierarchy provides a structure that organizes regional/continental vegetation patterns in the context of global patterns. A formal nomenclature is provided, along with a descriptive template that provides the differentiating criteria for each type at all levels of the hierarchy. Formation types have been described for the globe; divisions and macrogroups for North America, Latin America and Africa; groups, alliances and associations for the United States, parts of Canada, Latin America and, in partnership with other classifications that share these levels, many other parts of the globe

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

High Resolution Mapping of Tundra Ecosystems on Victoria Island, Nunavut – Application of a Standardized Terrestrial Ecosystem Classification

Rapid warming of Arctic climate is driving complex ecological changes in Arctic terrestrial ecosystems that are not well understood. These ecological changes have important implications for northern communities and Arctic ecosystem resilience. Researchers require baseline information on tundra ecosystem compo sition, structure and function at a range of scales to begin to understand how and why tundra ecosystems are changing to anticipate future changes and their impacts. Here we develop and assess a process for obtaining a high-resolution ecosystem map of terrestrial ecological communities for the Intensive Monitoring Area (IMA) of the Canadian High Arctic Research Station (CHARS) in Cambridge Bay, Nunavut. The methodology is based on a standardized classification of tundra ecosystems, and will provide an ecological template for designing and implementing ecosystem research, long-term monitoring experiments, and for linking local scale research to regional scales using remote sensing tools and models. Finally, we discuss opportunities and challenges regarding the mapping approach tested for the ecosystem classification, and the usefulness of the mapped result for a range of potential applications

Simplified Calculation of Maximum Conductor Tension at Two Stages of Their Movement During Short Circuit

The paper contains formulae of the simplified calculation of maximum conductor tension at stages of their movement during short circuit. Assurance estimation of the simplified calculation is done on the basis of the experimental data and calculative experiment. Correction factors for higher accuracy of the simplified calculation are proposed in the paper

Simplified Calculation of Maximum Conductor Tension at Two Stages of Their Movement During Short Circuit

<p class="1">The paper contains formulae of the simplified calculation of maximum conductor tension at stages of their movement during short circuit. Assurance estimation of the simplified calculation is done on the basis of the experimental data and calculative experiment. Correction factors for higher accuracy of the simplified calculation are proposed in the paper.</p

Vascular plants of Victoria Island (Northwest Territories and Nunavut, Canada): a specimen-based study of an Arctic flora

Victoria Island in Canada’s western Arctic is the eighth largest island in the world and the second largest in Canada. Here, we report the results of a floristic study of vascular plant diversity of Victoria Island. The study is based on a specimen-based dataset comprising 7031 unique collections from the island, including some 2870 new collections gathered between 2008 and 2019 by the authors and nearly 1000 specimens variously gathered by N. Polunin (in 1947), M. Oldenburg (1940s–1950s) and S. Edlund (1980s) that, until recently, were part of the unprocessed backlog of the National Herbarium of Canada and unavailable to researchers. Results are presented in an annotated checklist, including keys and distribution maps for all taxa, citation of specimens, comments on taxonomy, distribution and the history of documentation of taxa across the island, and photographs for a subset of taxa. The vascular plant flora of Victoria Island comprises 38 families, 108 genera, 272 species, and 17 additional taxa. Of the 289 taxa known on the island, 237 are recorded from the Northwest Territories portion of the island and 277 from the Nunavut part. Thirty-nine taxa are known on the island from a single collection, seven from two collections and three from three collections. Twenty-one taxa in eight families are newly recorded for the flora of Victoria Island: Artemisia tilesii, Senecio lugens, Taraxacum scopulorum (Asteraceae); Crucihimalaya bursifolia, Draba fladnizensis, D. juvenilis, D. pilosa, D. simmonsii (Brassicaceae); Carex bigelowii subsp. bigelowii, Eriophorum russeolum subsp. albidum (Cyperaceae); Anthoxanthum monticola subsp. monticola, Bromus pumpellianus, Deschampsia cespitosa subsp. cespitosa, D. sukatschewii, Festuca rubra subsp. rubra, Lolium perenne, Poa pratensis subsp. pratensis (Poaceae); Stuckenia filiformis (Potamogetonaceae); Potentilla × prostrata (Rosaceae); Galium aparine (Rubiaceae); and Salix ovalifolia var. ovalifolia (Salicaceae). Eight of these are new to the flora of the Canadian Arctic Archipelago: Senecio lugens, Draba juvenilis, D. pilosa, Anthoxanthum monticola subsp. monticola, Bromus pumpellianus, Deschampsia cespitosa subsp. cespitosa, Poa pratensis subsp. pratensis and Salix ovalifolia var. ovalifolia. One of these, Galium aparine, is newly recorded for the flora of Nunavut. Four first records for Victoria Island are introduced plants discovered in Cambridge Bay in 2017: three grasses (Festuca rubra subsp. rubra, Lolium perenne, and Poa pratensis subsp. pratensis) and Galium aparine. One taxon, Juncus arcticus subsp. arcticus, is newly recorded from the Northwest Territories. Of the general areas on Victoria Island that have been botanically explored the most, the greatest diversity of vascular plants is recorded in Ulukhaktok (194 taxa) and the next most diverse area is Cambridge Bay (183 taxa). The floristic data presented here represent a new baseline on which continued exploration of the vascular flora of Victoria Island – particularly the numerous areas of the island that remain unexplored or poorly explored botanically – will build

Vascular plants of Victoria Island (Northwest Territories and Nunavut, Canada): a specimen-based study of an Arctic flora

Victoria Island in Canada’s western Arctic is the eighth largest island in the world and the second largest in Canada. Here, we report the results of a floristic study of vascular plant diversity of Victoria Island. The study is based on a specimen-based dataset comprising 7031 unique collections from the island, including some 2870 new collections gathered between 2008 and 2019 by the authors and nearly 1000 specimens variously gathered by N. Polunin (in 1947), M. Oldenburg (1940s–1950s) and S. Edlund (1980s) that, until recently, were part of the unprocessed backlog of the National Herbarium of Canada and unavailable to researchers. Results are presented in an annotated checklist, including keys and distribution maps for all taxa, citation of specimens, comments on taxonomy, distribution and the history of documentation of taxa across the island, and photographs for a subset of taxa. The vascular plant flora of Victoria Island comprises 38 families, 108 genera, 272 species, and 17 additional taxa. Of the 289 taxa known on the island, 237 are recorded from the Northwest Territories portion of the island and 277 from the Nunavut part. Thirty-nine taxa are known on the island from a single collection, seven from two collections and three from three collections. Twenty-one taxa in eight families are newly recorded for the flora of Victoria Island: Artemisia tilesii, Senecio lugens, Taraxacum scopulorum (Asteraceae); Crucihimalaya bursifolia, Draba fladnizensis, D. juvenilis, D. pilosa, D. simmonsii (Brassicaceae); Carex bigelowii subsp. bigelowii, Eriophorum russeolum subsp. albidum (Cyperaceae); Anthoxanthum monticola subsp. monticola, Bromus pumpellianus, Deschampsia cespitosa subsp. cespitosa, D. sukatschewii, Festuca rubra subsp. rubra, Lolium perenne, Poa pratensis subsp. pratensis (Poaceae); Stuckenia filiformis (Potamogetonaceae); Potentilla × prostrata (Rosaceae); Galium aparine (Rubiaceae); and Salix ovalifolia var. ovalifolia (Salicaceae). Eight of these are new to the flora of the Canadian Arctic Archipelago: Senecio lugens, Draba juvenilis, D. pilosa, Anthoxanthum monticola subsp. monticola, Bromus pumpellianus, Deschampsia cespitosa subsp. cespitosa, Poa pratensis subsp. pratensis and Salix ovalifolia var. ovalifolia. One of these, Galium aparine, is newly recorded for the flora of Nunavut. Four first records for Victoria Island are introduced plants discovered in Cambridge Bay in 2017: three grasses (Festuca rubra subsp. rubra, Lolium perenne, and Poa pratensis subsp. pratensis) and Galium aparine. One taxon, Juncus arcticus subsp. arcticus, is newly recorded from the Northwest Territories. Of the general areas on Victoria Island that have been botanically explored the most, the greatest diversity of vascular plants is recorded in Ulukhaktok (194 taxa) and the next most diverse area is Cambridge Bay (183 taxa). The floristic data presented here represent a new baseline on which continued exploration of the vascular flora of Victoria Island – particularly the numerous areas of the island that remain unexplored or poorly explored botanically – will build

High‐resolution snow depth prediction using Random Forest algorithm with topographic parameters: A case study in the Greiner watershed, Nunavut

Increased surface temperatures (0.7℃ per decade) in the Arctic affects polar ecosystems by reducing the extent and duration of annual snow cover. Monitoring of these important ecosystems needs detailed information on snow cover properties at resolutions (< 100 m) that influence ecological habitats and permafrost thaw. A machine learning method using topographic parameters with the Random Forest (RF) algorithm previously developed in alpine environments was applied over an arctic landscape for the first time. The topographic parameters used in the RF algorithm were Topographic Position Index (TPI) and up-wind slope index (Sx), which were estimated from the freely available Arctic DEM at 2 m resolution. Addition of an ecotype parameter (proxy for vegetation height) showed minimal predictive improvement. Using RF, snow depth distributions were predicted from topographic parameters with a root mean square error = 8 cm (23%) (R^2 = 0.79) at 10 m resolution for an arctic watershed (1 500 km2) in western Nunavut, Canada