2,234 research outputs found
Concrete damage analysis based on higher-order beam theories using fracture energy regularization
This paper presents the numerical damage analysis of concrete structures using higher-order beam theories based on Carrera Unified Formulation (CUF). The concrete constitutive relation is modeled using continuum damage mechanics based on a modified Mazars concrete damage model, in which both the tensile and compressive softening behaviors are regularized with classical fracture energy methodology. An expression is proposed to estimate the characteristic length in higher-order beam theories, to prevent mesh dependency. Both softening constitutive laws and fracture energy calculations are obtained according to Model Code 2010. To assess the efficiency of the proposed model, three classical benchmark quasi-static experiments are taken for validation. From the comparison between numerical and experimental results, the proposed CUF model using continuum damage mechanics can present 3D accuracy with low computational costs and reduce the mesh dependency
Information communication between the library and the extension in the Brazilian Agricultural Research Corporation (Embrapa).
The exponential increase of information available and the potential mechanisms for storage and recovery made clear the need to extend the traditional concept of reference services/ mediation of information from libraries. The offer of information is located at the intersection of two fields of information science: the study of demands for profiles, and the organization, processing and availability of information for effective use. This work aims to present the experience related to the development of a project Embrapa Library System (SEB), whose main objective was to build interactive strategies of dissemination of knowledge generated by the Brazilian Agricultural Research Corporation (Embrapa). This project first resulted in a diagnosis of the extension in the state of RondĂ´nia, which supported the creation of online and offline customer service in libraries, creating an information channel with news about the world of scientific and technological information and training for extension in the use of database and digital repositories of Embrapa
Fano resonances in plasmonic core-shell particles and the Purcell effect
Despite a long history, light scattering by particles with size comparable
with the light wavelength still unveils surprising optical phenomena, and many
of them are related to the Fano effect. Originally described in the context of
atomic physics, the Fano resonance in light scattering arises from the
interference between a narrow subradiant mode and a spectrally broad radiation
line. Here, we present an overview of Fano resonances in coated spherical
scatterers within the framework of the Lorenz-Mie theory. We briefly introduce
the concept of conventional and unconventional Fano resonances in light
scattering. These resonances are associated with the interference between
electromagnetic modes excited in the particle with different or the same
multipole moment, respectively. In addition, we investigate the modification of
the spontaneous-emission rate of an optical emitter at the presence of a
plasmonic nanoshell. This modification of decay rate due to electromagnetic
environment is referred to as the Purcell effect. We analytically show that the
Purcell factor related to a dipole emitter oriented orthogonal or tangential to
the spherical surface can exhibit Fano or Lorentzian line shapes in the near
field, respectively.Comment: 28 pages, 10 figures; invited book chapter to appear in "Fano
Resonances in Optics and Microwaves: Physics and Application", Springer
Series in Optical Sciences (2018), edited by E. O. Kamenetskii, A. Sadreev,
and A. Miroshnichenk
Correlation between explosive strength and speed in young players
El objetivo del presente estudio fue determinar las relaciones entre la fuerza explosiva y la velocidad V(20m) en futbolistas cadetes y juveniles. Para el estudio fueron evaluados 18 jugadores de la categorĂa infantil y 18 de la categorĂa juvenil, siendo un total de 36 futbolistas. Se evaluĂł el peso corporal (kg), estatura (cm) y el % de grasa corporal. AsĂ como tambiĂ©n los test de squat Jump SJ(cm), CounterMovement Jump CMJ(cm) y saltos verticales contĂnuos en 5 segundos CJ5s(cm).
Los resultados muestran altas correlaciones entre SJ y CMJ (0,80), SJ y V(20m) ( 0,71) y CMJ y V(20m) (-0,61) en cadetes, asĂ como en juveniles SJ y CMJ (0,89) y SJ y V(20m) (-0,62), respectivamente. Por lo tanto, se concluye que la fuerza explosiva se encuentra en estrecha relaciĂłn con la velocidad (20m), tanto en jugadores de la categorĂa cadetes y juvenil.The aim of this study was to determine the relationship between the explosive power and speed V(20m) in children and youth players. For the study were evaluated 18 players in the cadet’s category and 18 in the youth category, for a total of 36 players. We assessed body weight (kg), height (cm) and% body fat, as well as the squat jump test, SJ (cm), countermovement jump CMJ (cm) and continuous vertical jumps in 5 seconds CJ5s (cm).
The results show high correlations between SJ and CMJ (0.80), SJ and V(20m) ( 0.71) and CMJ and V (20m) (-0.61) in cadet’s and youth in SJ and CMJ (0.89) and SJ and V(20m) (-0.62), respectively. Therefore, we conclude that the explosive force is closely related to the speed (20m), both players of the cadets and youth category.Peer Reviewe
Exact component-wise solutions for 3D free vibration and stress analysis of hybrid steel-concrete composite beams
Atividade alelopática em folhas de Tachigali myrmecophyla (Leg. - Pap.).
O uso de espĂ©cies florestais com atividade alelopática pode assegurar aos sistemas agroflorestais maior estabilidade, notadamente em relação Ă redução das espĂ©cies de plantas daninhas. Os objetivos deste trabalho foram isolar e identificar substâncias quĂmicas produzidas pelo Tachigali myrmecophyla (tachi-preto) e caracterizar a atividade alelopática sobre a germinação de sementes e o crescimento de plântulas de duas espĂ©cies de plantas daninhas. Os bioensaios foram realizados em condições controladas de 25 oC e fotoperĂodos de 12 horas para germinação e de 25 oC e fotoperĂodo de 24 horas para o desenvolvimento de radĂcula e hipocĂłtilo. Os extratos brutos e as frações foram analisados em concentração de 1,0 e 0,5%, e a substância, em concentrações de 5, 10, 15 e 20 mg L-1. O processo de isolamento permitiu a identificação da substância quĂmica 4,5-diidroblumenol A. Essa substância evidenciou atividade alelopática, cujos efeitos variaram em função da concentração, da espĂ©cie de planta daninha e do parâmetro da planta analisado. A intensidade dos efeitos alelopáticos esteve positivamente associada Ă concentração, com os efeitos mais intensos observados na concentração de 20 mg L-1. Independentemente do parâmetro analisado, os efeitos foram de maior magnitude na planta malĂcia. Comparativamente, o desenvolvimento da radĂcula se mostrou mais sensĂvel aos efeitos da substância que o desenvolvimento do hipocĂłtilo e a germinação das sementes
Potencial alelopático de catequinas de Tachigali myrmecophyla (leguminosae).
DisponĂvel tambĂ©m on-line
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