Determinação do autoamortecimento na condição limite de resistência à fadiga de cabos condutores

Monografia (graduação)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2015.Este trabalho apresenta uma metodologia de cálculo do autoamortecimento na condição limite de resistência à fadiga de condutores aéreos baseada no Princípio do Balanço de Energia e na Fórmula de Poffenberger-Swart. A revisão bibliográfica demonstra a complexidade envolvida nos fenômenos de vibração eólica e fadiga por fretting em fios de cabos condutores. No capítulo destinado aos resultados, aplica-se o método para a obtenção do autoamortecimento do cabo ACSR Drake exposto a uma velocidade de vento típica. Também implementa-se um código computacional para o cálculo do autoamortecimento requerido em condições diversas de regime de vento.This paper presents a methodology for calculating the self-damping in fatigue limit endurance condition of overhead conductors based on Energy Balance Principle and Poffenberger-Swart Formula. The literature review demonstrates the complexity involved in aeolian vibration and fretting fatigue of conductor strands phenomena. In the section for the results, it applies the method to obtain the ACSR Drake conductor self-damping exposed to a typical wind speed. It also implements a computer routine for calculating required damping for vary conditions of wind

Quadrângulos : uma abordagem etnomatemática

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Matemática, Programa de Mestrado Profissional em Matemática em Rede Nacional, 2019.Este trabalho investiga os métodos de Adão e de Jorge, utilizados por camponeses para “medir a terrra”. Nosso objetivo é construir conhecimento matemático a partir dessa abordagem etnomatemática. Realizamos um estudo exploratório desses modelos matemá- ticos para o problema de determinar a área de terrenos quadrangulares, e que fornecem aproximações para a área de quadrângulos convexos. Mostramos que todo quadrângulo torna-se cíclico via uma transformação que lhe preserva os lados. Provamos que, dentre os infinitos quadrângulos de lados dados, é cíclico o que tem a maior área. Demonstramos as fórmulas de Brahmagupta e de Coolidge (1939). Propomos uma melhora ao método de Jorge, e comparamos, com o auxílio do MATLAB (2010), os métodos de Adão, Jorge, Jorge melhorado e a fórmula de Brahmagupta ao modelo com um grau de liberdade, que fornece a área exata de quadrângulos planos e convexos. Demonstramos desigualdades que classificam esses métodos de aproximação.This work investigates the methods of Adão and Jorge, used by peasants to “measure the land”. Our goal is to build mathematical knowledge from this ethnomathematical approach. So we conduct an exploratory study of these mathematical models for the problem of determining the area of quadrangular terrain, which provide approximations for the area of convex quadrangles. We show that every quadrangle can become cyclic via a transformation that preserves its sides. We prove that among the infinite quadrangles of given sides, the one which has the largest area is cyclic. We give a proof to the formulas of Brahmagupta and Coolidge (1939). We propose an improvement to Jorge’s method, and compare, aided by MATLAB (2010), the methods of Adão and Jorge, improved Jorge’s method and Brahmagupta’s formula to the model with one degree of freedom, which gives the exact area of flat and convex quadrangles. We prove inequalities that classify these approximation methods.Este trabajo investiga los métodos de Adão y Jorge utilizados por los campesinos para «medir la tierra». Nuestro objetivo es construir conocimiento matemático a partir de este enfoque etnomatemático. Realizamos un estudio exploratorio de estos modelos matemáticos para el problema de determinar el área de terreno cuadrangular, y que proporcionan aproximaciones para el área de cuadrados convexos. Mostramos que cada cuadrángulo se vuelve cíclico a través de una transformación que conserva sus lados. Probamos que entre los infinitos cuadrángulos de lados dados es cíclico el que tiene el área más grande. Demostramos las fórmulas de Brahmagupta y de Coolidge (1939). Proponemos una mejora al método de Jorge y comparamos, con la ayuda de MATLAB (2010), los métodos de Adão, Jorge, Jorge mejorado y la fórmula de Brahmagupta, con el modelo con un grado de libertad, que da el área exacta de los cuadrángulos planos y convexos. Demostramos desigualdades que classifican estos métodos de aproximación.Cet travail étudie les méthodes d’Adão et Jorge, utilisées par les paysans pour «mesurer la terre». Notre objectif est de construire des connaissances mathématiques à partir de cette approche ethnomathématique. Nous avons mené une étude exploratoire de ces modèles mathématiques sur le problème de la détermination de la surface du terrain quadrangulaire et qui fournissant des approximations de la surface des quadrangles convexes. Nous montrons que chaque quadrangle devient cyclique via une transformation préservant ses côtés. Nous prouvons que parmi les infinis quadrangles de côtés donnés, c’est le cyclic qui a la plus grande surface. Nous démontrons les formules Brahmagupta et Coolidge (1939). Nous proposons une amélioration de la méthode de Jorge et comparons, à l’aide de MATLAB (2010), les méthodes d’Adão, Jorge, la méthode de Jorge améliorée, la formule de Brahmagupta, au modèle avec un degré de liberté, ce qui donne la surface exacte des quadrangles plates et convexes. Nous démontrons des inégalités qui classifient ces méthodes d’approximation

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications

Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications

NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications

NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications