Fundamentação teórica para uso de aplanático como concentrador térmico

The present work is to carry out theoretical basis of factors that affect the performance of solar concentration systems, and to present the aplanat as an alternative to solar concentration. A review is made and concepts such as spherical aberration and coma present in most mirrors and lenses. The aplanat, which has historically been used in precision devices such as telescope, and is currently also used as a hub forming free stock photo of spherical aberration and coma then appears. The work is aimed to provide the theoretical basis for the use of aplanatic concentrator and analyze the various configurations of it according to the dimensionless parameters that determine it. The most appropriate settings for the use of aplanático as concentrator are being analysed, and finally the effective concentrations obtained in both aplanatic elliptical and hyperbolic.O presente trabalho consiste em realizar fundamentação teórica de fatores que afetam o desempenho de sistemas de concentração solar, bem como apresentar o aplanático como uma alternativa à concentração solar. É feita uma revisão e conceitos como aberração esférica e coma presentes na maioria dos espelhos e lentes. Em seguida é apresentado o aplanático, que historicamente foi utilizado em dispositivos de precisão como telescópio, e atualmente é utilizado também como concentrador formador de imagem livre de aberração esférica e coma. O trabalho é voltado para fornecer o embasamento teórico para a utilização do aplanático na concentração solar, bem como analisar as diversas configurações dele de acordo com os parâmetros adimensionais que o determinam. Em seguida, são analisadas a configurações mais adequadas para o uso do aplanático como concentrador, e finalmente as concentrações efetivas obtidas tanto na configuração aplanático elíptico, quanto no aplanático hiperbólico.Tema 3: Energía solar, aplicaciones térmicas y químicas.Facultad de Arquitectura y Urbanism

Fundamentação teórica para uso de aplanático como concentrador térmico

The present work is to carry out theoretical basis of factors that affect the performance of solar concentration systems, and to present the aplanat as an alternative to solar concentration. A review is made and concepts such as spherical aberration and coma present in most mirrors and lenses. The aplanat, which has historically been used in precision devices such as telescope, and is currently also used as a hub forming free stock photo of spherical aberration and coma then appears. The work is aimed to provide the theoretical basis for the use of aplanatic concentrator and analyze the various configurations of it according to the dimensionless parameters that determine it. The most appropriate settings for the use of aplanático as concentrator are being analysed, and finally the effective concentrations obtained in both aplanatic elliptical and hyperbolic.O presente trabalho consiste em realizar fundamentação teórica de fatores que afetam o desempenho de sistemas de concentração solar, bem como apresentar o aplanático como uma alternativa à concentração solar. É feita uma revisão e conceitos como aberração esférica e coma presentes na maioria dos espelhos e lentes. Em seguida é apresentado o aplanático, que historicamente foi utilizado em dispositivos de precisão como telescópio, e atualmente é utilizado também como concentrador formador de imagem livre de aberração esférica e coma. O trabalho é voltado para fornecer o embasamento teórico para a utilização do aplanático na concentração solar, bem como analisar as diversas configurações dele de acordo com os parâmetros adimensionais que o determinam. Em seguida, são analisadas a configurações mais adequadas para o uso do aplanático como concentrador, e finalmente as concentrações efetivas obtidas tanto na configuração aplanático elíptico, quanto no aplanático hiperbólico.Tema 3: Energía solar, aplicaciones térmicas y químicas.Facultad de Arquitectura y Urbanism

The Astropy Problem

The Astropy Project (http://astropy.org) is, in its own words, "a community effort to develop a single core package for Astronomy in Python and foster interoperability between Python astronomy packages." For five years this project has been managed, written, and operated as a grassroots, self-organized, almost entirely volunteer effort while the software is used by the majority of the astronomical community. Despite this, the project has always been and remains to this day effectively unfunded. Further, contributors receive little or no formal recognition for creating and supporting what is now critical software. This paper explores the problem in detail, outlines possible solutions to correct this, and presents a few suggestions on how to address the sustainability of general purpose astronomical software

The repertoire of ICE in prokaryotes underscores the unity, diversity, and ubiquity of conjugation

Horizontal gene transfer shapes the genomes of prokaryotes by allowing rapid acquisition of novel adaptive functions. Conjugation allows the broadest range and the highest gene transfer input per transfer event. While conjugative plasmids have been studied for decades, the number and diversity of integrative conjugative elements (ICE) in prokaryotes remained unknown. We defined a large set of protein profiles of the conjugation machinery to scan over 1,000 genomes of prokaryotes. We found 682 putative conjugative systems among all major phylogenetic clades and showed that ICEs are the most abundant conjugative elements in prokaryotes. Nearly half of the genomes contain a type IV secretion system (T4SS), with larger genomes encoding more conjugative systems. Surprisingly, almost half of the chromosomal T4SS lack co-localized relaxases and, consequently, might be devoted to protein transport instead of conjugation. This class of elements is preponderant among small genomes, is less commonly associated with integrases, and is rarer in plasmids. ICEs and conjugative plasmids in proteobacteria have different preferences for each type of T4SS, but all types exist in both chromosomes and plasmids. Mobilizable elements outnumber self-conjugative elements in both ICEs and plasmids, which suggests an extensive use of T4SS in trans. Our evolutionary analysis indicates that switch of plasmids to and from ICEs were frequent and that extant elements began to differentiate only relatively recently. According to the present results, ICEs are the most abundant conjugative elements in practically all prokaryotic clades and might be far more frequently domesticated into non-conjugative protein transport systems than previously thought. While conjugative plasmids and ICEs have different means of genomic stabilization, their mechanisms of mobility by conjugation show strikingly conserved patterns, arguing for a unitary view of conjugation in shaping the genomes of prokaryotes by horizontal gene transfer