Crescimento e produção do cacaueiro em sistemas agroflorestais em função do manejo de plantas daninhas.

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Full-Wave Analysis of Stable Cross Fractal Frequency Selective Surfaces Using an Iterative Procedure Based on Wave Concept

This work presents a full-wave analysis of stable frequency selective surfaces (FSSs) composed of periodic arrays of cross fractal patch elements. The shapes of these patch elements are defined conforming to a fractal concept, where the generator fractal geometry is successively subdivided into parts which are smaller copies of the previous ones (defined as fractal levels). The main objective of this work is to investigate the performance of FSSs with cross fractal patch element geometries including their frequency response and stability in relation to both the angle of incidence and polarization of the plane wave. The frequency response of FSS structures is obtained using the wave concept iterative procedure (WCIP). This method is based on a wave concept formulation and the boundary conditions for the FSS structure. Prototypes were manufactured and measured to verify the WCIP model accuracy. A good agreement between WCIP and measured results was observed for the proposed cross fractal FSSs. In addition, these FSSs exhibited good angular stability

Assessing the time-frequency co-movements among the five largest engineering consulting companies: A wavelet-base metrics of contagion and VaR ratio

Diversification in a portfolio is an important tool for the systematic risk management that is inherent to different asset classes. The composition of a portfolio with domestic and international assets is seen as one of the main alternatives for building a diversified portfolio, as this approach tends to reduce portfolio return exposure depending on country factors. However, in scenarios where industry factors are predominant, international diversification can increase systematic risk in a portfolio centered on a single asset class. This study is a pioneer in using wavelet-based methods to identify intersectoral co-movements, based on a portfolio of shares of the world’s top five consulting engineering companies, providing an innovative way to be applied to this phenomenon. Our evidence indicates that companies share a strong pattern of co-movements among themselves, especially in cycles of 32 to 64 days, suggesting a higher exposure to risk for portfolios with an investment horizon in long-term cycles.info:eu-repo/semantics/publishedVersio

Visualização da topologia do escoamento na vizinhança de uma porta vedada por um aparelho de cortina de ar

Descrevem-se as metodologias utilizadas num estudo que teve por objectivo a avaliação do efeito de vedação promovido por um aparelho de cortina de ar. Foi utilizada uma instalação experimental à escala real em que, através de um jacto de ar descendente gerado por cima da porta, se procurou manter uma dada diferença de temperatura entre duas salas contíguas. Recorrendo a 16 sondas anemométricas, efectuou-se o mapeamento da temperatura e da velocidade do ar em diversos planos considerados de interesse e, através da aquisição desses dados em contínuo, avaliou-se o desenvolvimento e a estabilidade do jacto durante os primeiros minutos de funcionamento da instalação. Recorreu-se igualmente a uma técnica de medida do tipo “whole-field” em que o campo de temperaturas do ar é medido indirectamente através de um ecrã de baixa massa térmica que serve de alvo a uma câmara termográfica de infra-vermelhos. Ao longo do artigo serão apresentados vários exemplos elucidativos das potencialidades das técnicas descritas anteriormente

Rendimento de massa e características morfológicas de Crotalaria ochroleuca em populações de plantas.

JIPE 2013

Influence of seesaw permanent movement of a person on the performance of an air curtain device

In commercial and industrial activities, there is often a need for reducing or controlling heat and mass transfer between outside environment and indoor compartments with controlled atmosphere, warranting, simultaneously, an easy circulation of people and equipments. In practical terms, the confinement of a given space can be achieved with aerodynamic barriers (air curtains) constituted by one or more air jets. In the present paper, the loss of efficiency of a vertical downward air curtain due to the seesaw permanent movement of a person is analyzed. Results show a systematic loss of the sealing efficiency (10 to 20%) of the air curtain device when the doorway is periodically crossed by a computer controlled manikin “Roberta” relatively to the results obtained without this traversing movement

Aspectos da produção de dois híbridos de melão em função de diferentes fontes de nitrogênio.

O objetivo deste trabalho foi de avaliar a produção dos híbridos

Determination of metabolite profiles in tropical wines by 1H NMR spectroscopy and chemometrics.

The aim of this work was to determine metabolite profiles of tropical wines produced in northeast Brazil, by using 1H NMR spectroscopy in comoination with chemometric methods to analyze and discrirninate wine samples from 2007 vintages produced by different wineries

The study of events approach applied to the impact of mergers and acquisitions on the performance of consulting engineering companies

Recent research suggests that one of the main motivations for mergers and acquisitions is the attempt to acquire companies to incorporate intangible assets. Such assets provide important sources of sustainable competitive advantages and opportunities for growth. This article analyzes the strategies of engineering companies, as well as value creation in acquisition events of multinational companies, by using the study of the events method, providing an innovative way to be applied to this phenomenon. This method is used in our research to study the influence of the announcement of acquisitions on the abnormal accumulated returns of the acquiring companies, and is allowed to confirm that influence. In general, the average accumulated returns were positive and statistically significant in the three windows of the method, according to the significance tests used. The results validate the hypothesis that the events generate synergy gains for market players, emphasizing the importance of growth via acquisitions for the sector under analysis.info:eu-repo/semantics/publishedVersio