Electrostatic self-force in (2+1)-dimensional cosmological gravity

Point sources in (2+1)-dimensional gravity are conical singularities that modify the global curvature of the space giving rise to self-interaction effects on classical fields. In this work we study the electrostatic self-interaction of a point charge in the presence of point masses in (2+1)-dimensional gravity with a cosmological constant.Comment: 9 pages, Late

Efeito de antioxidantes na conservação do coco verde descascado.

O objetivo do presente estudo foi estudar o efeito de agentes sulfitantes e ácidos orgânicos na conservação e manutenção da aparência do coco verde descascado, envolvido em filme de polietileno de baixa densidade e mantido sob refrigeração

A model to simulate the contribution of fibre reinforcement for the punching resistance of RC slabs

In this paper analytical formulations are developed for the prediction of the punching resistance of flat slabs 17 of steel fibre reinforced concrete (SFRC) flexurally reinforced with steel bars. By performing statistical 18 analysis with a database that collects experimental results on the characterization of the post-cracking 19 behaviour of SFRC, equations are determined for the evaluation of the residual flexural tensile strength 20 parameters (fRi) from fundamental data that characterize steel fibres. The fRi strength parameters proposed by 21 CEB-FIP 2010 were used for the definition of the stress-crack width law (s-w) that simulates the fibre 22 reinforcement mechanisms in cement based materials. In the second part of the paper is described an 2 analytical formulation based on the concepts proposed by Muttoni and Ruiz, where 23 the s-w law is 24 conveniently integrated for the simulation of the contribution of steel fibres for the punching resistance of 25 SFRC slabs. By using a database composed of 154 punching tests with SFRC slabs, the good predictive 26 performance of the developed proposal is demonstrated. The good performance of this model is also 27 evidenced by comparing its predictions to those from other models.Fundação para a Ciência e a Tecnologia (FCT

The predictive performance of design models for the punching resistance of SFRC slabs in inner column loading conditions

In the recent years steel fibre reinforced concrete (SFRC), in a volume percentage between 0.75 and 1.25, is being proposed to build slabs supported on piles and slabs supported on columns, where the unique conventional reinforcement is composed of some steel bars in the alignments of the columns/piles, designated as anti-progressive collapse bars. Punching resistance, however, can be a concern in this structural system. In fact, punching has a brittle failure character, and the prediction of the punching resistance is still a challenge, even in concrete slabs with traditional reinforcement systems. The difficulties on assessing the contribution of the reinforcement mechanisms of steel fibres for the flexural and shear resistance in the critical punching perimeter increase this complexity. The research carried out in this paper has the purpose of assessing the reliability of existing analytical models for the prediction of the punching resistance of SFRC slabs. For this purpose, a data-base of experimental tests with SFRC slabs failing in punching was built and the predictive performance of four analytical available models was assessed. In order to turn more practical the model that is more reliable from physical and mechanical point of views, the concepts proposed by Model Code 2010 for the characterization of the postcracking behaviour of FRC were introduced in this model

Choosing Well Your Opponents: How to Guide the Synthesis of Programmatic Strategies

This paper introduces Local Learner (2L), an algorithm for providing a set of reference strategies to guide the search for programmatic strategies in two-player zero-sum games. Previous learning algorithms, such as Iterated Best Response (IBR), Fictitious Play (FP), and Double-Oracle (DO), can be computationally expensive or miss important information for guiding search algorithms. 2L actively selects a set of reference strategies to improve the search signal. We empirically demonstrate the advantages of our approach while guiding a local search algorithm for synthesizing strategies in three games, including MicroRTS, a challenging real-time strategy game. Results show that 2L learns reference strategies that provide a stronger search signal than IBR, FP, and DO. We also simulate a tournament of MicroRTS, where a synthesizer using 2L outperformed the winners of the two latest MicroRTS competitions, which were programmatic strategies written by human programmers.Comment: International Joint Conference on Artificial Intelligence (IJCAI) 202

Alterações físico-químicas da água de coco durante o desenvolvimento do fruto.

O presente trabalho teve como objetivo estudar as alterações físico-químicas que ocorrem na água do fruto do coqueiro anão, ao longo do seu desenvolvimento, de modo a possibilitar a determinação do estádio de desenvolvimento mais adequado para a colheita de frutos que são destinados ao fornecimento de água para consumo ao natural ou para o envasamento industrial

Condutitvidade hisráulica do solo coeso dos tabuleiros costeiros cultivado com citros.

Avalia através da determinação da condutividade hidráulica não saturada, o movimento de água em agrissolo acinzentado coeso dos tabuleiros costeiros cultivado com citros.bitstream/CPATC/19569/1/bp-22.pdfISSN 1678-1961