Electrical sensor development for the dielectric properties measurement and moisture content estimation of switchgrass and corn stover

The dielectric properties of material play a relevant role when developing moisture content sensors of agricultural products. However, little is known about the permittivity of switchgrass and corn stover in a wider frequency band. Thus, this research goal was to determine their dielectric constant and loss factor at different moisture contents and frequency range of 5 Hz to 13 MHz. Also, an electrical sensor system was developed to predict the amount of water in agricultural products with the material static and in movement. The dielectric properties of switchgrass and corn stover were calculated by measuring their admittance using an impedance analyzer at three different moisture content levels, approximately between 9 and 30.5% and a fixed bulk density of 0.133 g/cm3. Overall, it was observed that the dielectric properties of these materials increased with moisture content but decreased with frequency. Prediction models were developed using the data of a frequency range of 10 kHz to 5 MHz. These models R2\u27s were higher than 0.90 in general; however, the R2 was 0.9811 for a model in a frequency range from 100 kHz to 5 MHz for the loss factor of switchgrass in movement. A sensor system was designed to generate and read a super-imposed multi-frequency signal that was sent and received from a device under test (DUT) with switchgrass. These input and output signals were analyzed to estimate the moisture content at four levels. Overall, the attenuation between the input and output waves increased with moisture. Two models were created to estimate water from switchgrass. They had an R2 of 0.7901 and 0.9976 for the material static and in movement, respectively. The permittivity of switchgrass and corn stover were successfully estimated for the frequency range of 10 kHz to 5 MHz at three moisture levels. Additionally, the developed sensor system was capable of sensing the moisture of switchgrass, but more investigation is necessary. This study helps to comprehend the influence of the electric field at different frequencies on these materials

Topology and Dynamics in Complex Networks: The Role of Edge Reciprocity

A key issue in complex systems regards the relationship between topology and dynamics. In this work, we use a recently introduced network property known as steering coefficient as a means to approach this issue with respect to different directed complex network systems under varying dynamics. Theoretical and real-world networks are considered, and the influences of reciprocity and average degree on the steering coefficient are quantified. A number of interesting results are reported that can assist the design of complex systems exhibiting larger or smaller relationships between topology and dynamics

An Alternative Method to Evaluate Complex Information Technology Projects

For most companies, it is a reality to face uncertainties when conducting complex projects focused on the implementation of Information Systems (IS) and, as a consequence, cost-benefit evaluation of this kind of projects has become a difficult task. In this context, Real Options Theory (ROT) has proved to be a viable alternative to provide methods to evaluate complex projects, not only in Information Technology but in many other economics and business areas. This paper intends to demonstrate how ROT can be applied to evaluate complex Information Technology projects, exploring a case study involving an implementation project of an Enterprise Resource Planning (ERP). In the case study, two distinct solutions for the implementation of an ERP were evaluated, demonstrating the applicability of ROT to such complex situations

A Guerra do Paraguai em manuais didáticos: fontes para análise da cultura escolar e da cultura histórica

Anais do XVII Congresso Internacional das Jornadas de Educaão História - teoria, pesquisa e prática - I Encontro da AIPEDH - Associação Iber-Americana de Pesquisadores em Educação História, realizado pela Universidade Federal da Integração Latino-Americana, entre 02, 03 e 04 de agosto de 2017.A Guerra da Tríplice Aliança, ou Guerra do Paraguai, tem sido tema de pesquisa e debate desde a época do fim do conflito em 1870. Ao largo deste período diversas interpretações, abordagens e métodos historiográficos produziram mudanças nas formas de narrar essa história, sendo possível destacar três grandes vertentes historiográficas sobre o conflito: a versão tradicionalista; revisionista; e a neorrevisionista. O presente trabalho toma como fonte de investigação manuais didáticos de história, entendidos como fontes para análise da cultura escolar (FORQUIN, 1993) e da cultura histórica (RÜSEN, 1994), com o objetivo de identificar as relações entre as narrativas produzidas pelos manuais e as influências recebidas das diversas vertentes historiográficas. Espera- se, com isso, problematizar as relações entre a história produzida nas universidades e a história vivenciada na escola, contribuindo para ampliação das discussões sobre a didática da história e a cultura históricaUNIL

Memristors : a journey from material engineering to beyond Von-Neumann computing

Memristors are a promising building block to the next generation of computing systems. Since 2008, when the physical implementation of a memristor was first postulated, the scientific community has shown a growing interest in this emerging technology. Thus, many other memristive devices have been studied, exploring a large variety of materials and properties. Furthermore, in order to support the design of prac-tical applications, models in different abstract levels have been developed. In fact, a substantial effort has been devoted to the development of memristive based applications, which includes high-density nonvolatile memories, digital and analog circuits, as well as bio-inspired computing. In this context, this paper presents a survey, in hopes of summarizing the highlights of the literature in the last decade

Management practices and influences on IT architecture decisions: a case study in a telecom company

The study aims to analyze the IT architecture management practices associated with their degree of maturity and the influence of institutional and strategic factors on the decisions involved through a case study in a large telecom organization. The case study allowed us to identify practices that led the company to its current stage of maturity and identify practices that can lead the company to the next stage. The strategic influence was mentioned by most respondents and the institutional influence was present in decisions related to innovation and those dealing with a higher level of uncertainties

Análise morfométrica de frutos e sementes de Annona crassiflora Mart. (annonaceae) do Brasil Central

Com a existente redução da cobertura vegetal do Cerrado, diversas espécies arbóreas têm suas áreas de ocorrência diminuídas e como consequência perdem parte de sua diversidade genética. Para contrapor este cenário faz-se necessário conhecer a diversidade genética afim de embasar projetos e medidas práticas de conservação. Assim, este trabalho teve como objetivo investigar a variabilidade genética populacional de Annona crassiflora por meio de dados morfométricos de frutos e sementes em quatro populações no Brasil central. No total foram obtidos 152 frutos de 73 matrizes dos quais foram medidos a altura, diâmetro, massa do fruto, massa de 100 sementes e número de sementes por fruto. Os frutos foram despolpados e as semente retiradas para se medir a altura, largura e espessura. O estudo de cluster hierárquico mostrou o agrupamento de 11 pequenos grupos e dois grandes grupos, sendo que nestes dois grandes grupos há representantes das quatro populações amostradas. Isso mostra que não há uma divisão específica das populações, indicando alta variabilidade genética. Os frutos da população de Buritis foram, via de regra, significativamente maiores que das outras populações o que pode evidenciar distanciamento genético ou diferentes condições ambientais de polinização. Este padrão não foi observado nas analise das dimensões das sementes, embora tenha havido diferença estatística entre as populações. De forma geral as maiores dimensões foram encontradas nas populações de Planaltina e Buritis. Diante disso as análises indicam alta diversidade genética e frutos/sementes com dimensões maiores nos locais com melhor estado de conservação.With the existing reduction of the vegetation cover of the Cerrado, several tree species have their areas of occurrence diminished, and as a consequence, they lose part of their genetic diversity. To counter this scenario it is necessary to know the genetic diversity in order to base projects and practical conservation measures. Thus, the objective of this work was to investigate the genetic variability of Annona crassiflora by means of morphometric data of fruits and seeds in four populations in central Brazil. In total, 152 fruits were obtained from 73 matrices, of which the height, diameter, fruit mass, mass of 100 seeds and number of seeds per fruit were measured. The fruits were stripped and the seed removed to measure their height, width and thickness. The hierarchical cluster study showed the grouping of 11 small groups and two large groups, and in these two large groups there are representatives of the four populations sampled. This shows that there is no specific division of populations, indicating high genetic variability. The fruits of the Buritis population were, as a rule, significantly larger than those of other populations, which may indicate genetic distancing or different environmental conditions of pollination and dispersion. This pattern was not observed in the seed size analysis, although there was a statistical difference between the populations. In general, the largest dimensions were found in the populations of Planaltina and Buritis. Therefore, the analyzes indicate high genetic diversity and fruits/seeds with larger dimensions in the best-preserved state

Probing the Ionic Dielectric Constant Contribution in the Ferroelectric Phase of the Fabre-Salts

In strongly correlated organic materials it has been pointed out that charge-ordering could also achieve electronic ferroelectricity at the same critical temperature $T_{co}$. A prototype of such phenomenon are the quasi-one dimensional (TMTTF)$_2X$ Fabre-salts. However, the stabilization of a long-range ferroelectric ground-state below $T_{co}$ requires the break of inversion symmetry, which should be accompanied by a lattice deformation. In this work we investigate the role of the monovalent counter-anion $X$ in such mechanism. For this purpose, we measured the quasi-static dielectric constant along the $c^{*}$-axis direction, where layers formed by donors and anions alternate. Our findings show that the ionic charge contribution is three orders of magnitude lower than the intra-stack electronic response. The $c^{*}$ dielectric constant ($\epsilon'_{c^*}$) probes directly the charge response of the monovalent anion $X$, since the anion mobility in the structure should help to stabilize the ferroelectric ground-state. Furthermore, our $\epsilon'_{c^*}$ measurements %conjugated with earlier investigations of the $c^*$ lattice thermal expansion, show that the dielectric response is thermally broaden below $T_{co}$ if the ferroelectric transition occurs in the temperature range where the anion movement begin to freeze in their methyl groups cavity. In the extreme case of the PF$_6$-H$_{12}$ salt, where $T_{co}$ occurs at the freezing point, a relaxor-type ferroelectricity is observed. Also, because of the slow kinetics of the anion sub-lattice, global hysteresis effects and reduction of the charge response upon successive cycling are observed. In this context, we propose that anions control the order-disorder or relaxation character of the ferroelectric transition of the Fabre-salts.Comment: 8 pages, 7 figures. To appear in Physical Review