Modelagem numérica de estruturas de contenção atirantadas em areia

A numerical study on the behavior of tied-back retaining walls in sand, using the finite element method (FEM) is presented. The analyses were performed using the software Plaxis 2D, and were focused on the development of horizontal displacements, horizontal stresses, shear forces and bending moments in the structure during the construction process. Emphasis was placed on the evaluation of wall embedment, tie-back horizontal spacing, wall thickness, and free anchor length on wall behavior. A representative soil profile of a specific region at the City of Natal, Brazil, was used in the numerical analyses. New facilities built on this region often include retaining structures of the same type studied herein. Soil behavior was modeled using the Mohr-Coulomb constitutive model, whereas the structural elements were modeled using the linear elastic model. Shear strength parameters of the soil layers were obtained from direct shear test results conducted with samples collected at the studied site. Deformation parameters were obtained from empirical correlations from SPT test results carried out on the studied site. The results of the numerical analyses revealed that the effect of wall embedment on the investigated parameters is virtually negligible. Conversely, the tie-back horizontal spacing plays an important role on the investigated parameters. The results also demonstrated that the wall thickness significantly affects the wall horizontal displacements, and the shear forces and bending moments within the retaining structure. However, wall thickness was not found to influence horizontal stresses in the structure

Produtividade do milho relacionada com a resistência mecânica à penetração do solo sob preparo convencional

A resistência mecânica do solo à penetração exerce grande influência sobre o desenvolvimento vegetal, uma vez que o crescimento das raízes e a produtividade das culturas variam de forma inversamente proporcional ao seu valor. O objetivo do trabalho foi estudar a variabilidade espacial e a correlação entre a produtividade do milho (PG) e a resistência mecânica do solo à penetração (RP) de um Latossolo Vermelho sob preparo convencional, em área pertencente à Fazenda Experimental de Ensino e Pesquisa da Faculdade de Engenharia - FE/UNESP - Câmpus de Ilha Solteira. Foram definidos 133 pontos de amostragem no campo, segundo malha com espaçamento regular de 10,0 m, nos quais foram medidas a RP, a umidade gravimétrica (UG), nas camadas de 0-0,10; 0,10-0,20; 0,20-0,30 e 0,30-0,40 m, e a PG. O modelo exponencial mostrou-se adequado para descrever todos os semivariogramas experimentais construídos. A RP e a UG apresentaram moderada dependência espacial, com alcance variando entre 20,2 e 63,0 m. A PG apresentou forte dependência espacial com alcance de 15,3 m. A RP não apresentou correlação espacial com a PG. Valores de RP variando entre 0,9 e 2,0 MPa não restringiram a PG.

Densidade relativa ótima de Latossolos Vermelhos para a produtividade de soja

A compactação do solo tem causado decréscimos na produtividade de soja, e os valores de densidade do solo a partir dos quais a produtividade decresce são pouco conhecidos. Assim, este trabalho objetivou avaliar a produtividade de soja (cv. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 48) em relação à densidade relativa (Dsr) de Latossolo Vermelho textura média (LVd) e argilosa (LVef). em 2001/2002, foi realizado um experimento em casa de vegetação, com amostras coletadas nos dois solos na camada de 0,0-0,2 m, peneirados a 4,0 mm, adubados e compactados em camadas de 3,0 cm, em vasos de 20 cm de altura e 25 cm de diâmetro. Foram estabelecidos quatro níveis de compactação e dois de água no solo (tensão de 0,01 e 0,05 MPa), com três repetições. A soja foi semeada em novembro (duas plantas por vaso) e irrigada duas vezes ao dia. No segundo experimento, no campo (2002/2003), utilizou-se apenas o LVd que foi compactado por meio de passadas de trator com quatro pneus de mesma largura, estabelecendo-se cinco níveis de compactação, com quatro repetições. A soja foi semeada, em dezembro de 2002, no espaçamento de 0,45 m entre linhas e 20 plantas por metro. Foram determinadas a densidade do solo (Ds) e a Ds máxima pelo teste de Proctor, sendo a Dsr obtida por divisão da Ds pela Ds máxima. Na colheita, foi avaliada a produtividade de grãos. A Dsr ótima para a produtividade de soja, em casa de vegetação, foi superior no Latossolo Vermelho eutroférrico argiloso (0,84), comparada à do Latossolo Vermelho caulinítico de textura média (0,75), na tensão de água no solo de 0,01 MPa. No campo, a Dsr ótima para soja foi de 0,80.

Atividade de proteases e disponibilidade de nitrogênio para laranjeira cultivada em Latossolo Vermelho distrófico

O conhecimento do potencial da mineralização dos compostos orgânicos nitrogenados do solo é fundamental para o uso eficiente do N em sistemas de produção agrícola. Com o objetivo de avaliar a atividade de proteases e suas relações com os teores de diferentes formas de N em Latossolo Vermelho distrófico cultivado com laranjeira, foram coletadas amostras de solo em duas profundidades (0-10 e 10-20 cm), na linha de projeção da copa e nas entrelinhas, nos meses de novembro e dezembro/98, fevereiro e março/99. em março/99, época recomendada para a diagnose foliar, também foram coletadas amostras de folhas. As amostras de solo foram avaliadas com relação à atividade de proteases e aos teores de N-amoniacal, N-nitrato, N-total, N-amoniacal obtido após incubação anaeróbia (N-pot) e N-amoniacal extraído por solução de CaCl2 sob autoclavagem (N-autoclave). Nas amostras de folha, determinou-se o teor de N-total. A atividade de proteases foi influenciada pelo local e pela profundidade de amostragem, tendo sido mais elevada na linha de projeção da copa e profundidade de 0-10 cm. A aplicação de fertilizante orgânico causou aumento na atividade de proteases, principalmente na camada de 0-10 cm. O coeficiente de correlação entre atividade de proteases e outros métodos para avaliação da disponibilidade de N dependeu da época, do local e da profundidade de amostragem. A correlação entre o N-foliar, obtido na época indicada para diagnose foliar, a atividade de proteases e as demais formas para avaliar disponibilidade de N (N-amoniacal, N-nitrato, N-autoclave e N-pot) variou com a época de amostragem. A atividade de proteases foi positiva e altamente correlacionada com o N-foliar, obtido na época indicada para fins de diagnose foliar, para amostras de terra retiradas nas entrelinhas (0-10 cm), no mês de dezembro/1998.

Estudo numérico do comportamento de muros de arrimo em alvenaria estrutural de blocos vazados

Usually masonry structures has low tension strength, hence the design to flexural efforts can results in high reinforcement ratio, specification of high unit and prism strength, structural members with larger section dimensions and modification in structural arrangement to be possible to use masonry members. The main objective of this study is to evaluate the stiffness, the efforts distribution and the effect of horizontal elements (girders) and vertical elements (counterforts) distribution on the behavior of masonry blocks retaining walls. For this purpose, numerical modeling was performed on typical retaining wall arrangements by varying the amount and placement of horizontal and vertical elements, beyond includes elements simulating the reactions of the soil supporting the foundation of the wall. The numerical modeling also include the macro modeling strategy in which the units, mortar and grout are discretized by a standard volume that represents the masonry elastic behavior. Also, numerical model results were compared with those ones of simplified models usually adopted in bending design of masonry elements. The results show horizontal displacements, principal and shear stresses distribution, and bending moments diagrams. From the analysis it was concluded that quantity and manner of distribution of the girders are both important factors to the panel flexural behavior, the inclusion of the foundation changed significantly the behavior of the wall, especially the horizontal displacements, and has been proposed a new way of considering the flanges section of the counterforts

Aspectos linguístico-ergonômicos em rótulos: avaliação da linguagem verbo-visual de rótulos de embalagens para alimentos achocolatados

We have been living in a world of packed products. The package and the labels support the companies to communicate with the customers in addition to give protection, storage and convenience in proportion to the products that move in the price list. The labels mainly add up a value which helps the companies differ their products and increase the value of the brands among the final customers. However, the information given in the label are not clear sometimes. It displays a verbal-visual defective language resulted from a poor visibility, legibleness and comprehensibleness of the verbal and visual marks. The aim of this research is to verify, according to the costumers‟ view, the level of the clarity in the informative texts, harmony and ergonomic conformity of the package labels in the chocolate powder of the Claralate brand, considering the linguistic aspects presented on the labels. The criteria to evaluate the chocolate package selected were based on the linguistic field: the organization and the structure of the text derided from the classification of the textual genre; the clarity and the comprehension of the language utilized on those labels. From the ergonomic view, the informative and ergonomic conformity, based on the following requirements: legibility, symbols, characters, reading fields and intermission of the written lines. Therefore, the research done july 2007 and added july 2011 had a structured questionnaire in the interview put to the 118 customers of the chocolate package that go shopping in one of the two supermarkets in Floriano, Piauí São Jorge and/or Super Quaresma. The main results of the investigation show that the linguistic aspects in the informative texts of the labels provide the customers‟ expectancy partially, while the consideration of the informative ergonomic analyzed can contribute to the improvement of the information and consequent visual progress of those, on the labels of chocolate package investigated. As recommendation towards the maker of the product, the outcome of the research indicates: harmonize the proportion of the letters and numbers; enlarge the letters size; make the visual information more comprehensive determined by the reading field; put the expiry date in a better visual place

Arranjo de antenas de microfita com substrato anisotrópico com patch supercondutor e aplicações em nanotecnologia

The main objective in this work is the analysis of resonance frequency microstrip structures with glass fiber and electromagnetic band gap (EBG/PBG) substrate and analysis of microstrip antennas with rectangular patch of superconductor of high critical temperature (HTS). In this work was used the superconductors YBCO (critical temperature of 90K), SnBaCaCuOy (critical temperature of 160K), and Sn5InCa2Ba4Cu10Oy (critical temperature of 212K) with results in Gigahertz and Terahertz. Was used microstrip antennas arrays planar and linear phase and linear phase planar with patch with superconductor. It presents a study of the major theories that explain superconductivity. In phase arrays were obtained the factors arrays for such configurations, and the criteria of phase and spacing between the elements compound in the array, which were examined in order to get a main lobe with high directivity and high gain. In the analysis we used the method of Transverse Transmission Line (TTL) used in domain of the Fourier Transform (FTD). The LTT is a full wave method, which obtains the electromagnetic field in terms of the components transverse of the structure. The addition of superconductive patch is made using the boundary condition resistive complex. Results are obtained resonance frequency as a function of the parameters of the antenna, radiation patterns of the E and H Planes, for the phase antenna arrays in linear and planar configurations, for different values of the phase and the spacing between elements

Materiais supercondutores HTS para arranjos de antenas e aplicação de PBG para micro-ondas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fibra de crital fotônico: fundamentação e aplicações

The main purpose of this dissertation, consists of the study and analysis of the PBG (Photonic Band Gap )..tecnology incorporated in optical fiber structures. So, we'l1 present a complete PBG structure theory, and folowing this, we'l1 present also a chapter for convencional optical fiber, due to the need to construct the base theory of them, and latter a more complete work about photonic crystal fiber. Finaly, we'l1 show the results of the signals , dispersion, and obtained curves under the right dimensions according to the required signals, for convencional optical and photonic crystal fiber. Knowing that PBG crystals with low losses act as perfect mirrors for forbidden frequences and knowing that the persence of structures of PBG as substrates, brings some desirable characteristics such as spontaneous emition supression and superficial waves. We' 11 show according to these characteristics its applications in telecomunication. Therefore, the enphasis of this work is to show that the optical fibers are the only practible thing to integrate the enormous quantity of data and video at intemet' s market, developing, manipulating, changing, and multiplexing the optical fibers chanels in an area where we expect that the photonic crystals has an important hole, since the photonic crystals can be projected and made to avoid losses in the bands of certain wavelength which permits the increase in efficiency ofthe optical components projected with crystals. A sequence of this work would be the utilisation of the PBG structures in the new system of optical network without fiber developed by Bell laboratories of the lucent tecnology, last year using light rays for transmiting information through the air. The new system of optical networks without fiber will permit sending the data of 15 cd-rooms in less then one second, what represents 65 times more information than those transmitted through the actual radio frequences

Aplicações de arranjos de antenas de microfita com patch supercondutor

This work has as main objective the study of arrays of microstrip antennas with superconductor rectangular patch. The phases and the radiation patterns are analyzed. A study of the main theories is presented that explain the microscopic and macroscopic phenomena of superconductivity. The BCS, London equations and the Two Fluid Model, are theories used in the applications of superconductors, at the microstrip antennas and antennas arrays. Phase Arrangements will be analyzed in linear and planar configurations. The arrangement factors of these configurations are obtained, and the phase criteria and the spacing between the elements, are examined in order to minimize losses in the superconductor, compared with normal conductors. The new rectangular patch antenna, consist of a superconducting material, with the critical temperature of 233 K, whose formula is Tl5Ba4Ca2Cu9Oy, is analyzed by the method of the Transverse nTransmission Line (TTL), developed by H. C. C. Fernandes, applied in the Fourier Transform Domain (FTD). The TTL is a full-wave method, which has committed to obtaining the electromagnetic fields in terms of the transverse components of the structure. The inclusion of superconducting patch is made using the complex resistive boundary condition, using the impedance of the superconductor in the Dyadic Green function, in the structure. Results are obtained from the resonance frequency depending on the parameters of the antenna using superconducting material, radiation patterns in E-Plane and H -Plane, the phased antennas array in linear and planar configurations, for different values of phase angles and different spacing between the elements

EFEITOS DE DIFERENTES ESPAÇAMENTOS ENTRE SULCOS NA PRODUTIVIDADE AGRÍCOLA da CANA-DE-AÇÚCAR (Saccharum spp.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Antenas de microfita com patch supercondutor a 212 K

This work has as main objective to study the application of microstrip antennas with patch and use of superconducting arrays of planar and linear phase. Was presented a study of the main theories that explain clearly the superconductivity. The BCS theory, Equations of London and the Two Fluid Model are theories that supported the implementation of the superconducting microstrip antennas. Arrangements phase was analyzed in linear and planar configuration of its antennas are reported factors such arrays to settings and criteria of phase and the spacing between the elements that make the arrayst was reviewed in order to minimize losses due to secondary lobes. The antenna used has a rectangular patch Sn5InCa2Ba4Cu10Oy the superconducting material was analyzed by the method of Transverse Transmission Line (TTL) applied in the field of Fourier transform (FTD). The TTL is a full-wave method, which has committed to obtaining the electromagnetic fields in terms of cross-cutting components of the structure. The inclusion of superconducting patch is made using the boundary condition, complex resistive. Are obtained when the resonant frequency depending on the parameters of the antenna, radiation pattern of E-Plan and H-Plan for the M-phase arrangements of antennas in the linear and planar configurations for different values of phase and spacing between the elements.

Avaliação de diferentes materiais no ensacamento de pêssegos

O trabalho foi realizado em um pomar comercial de pêssego da cultivar Aurora 2, de três anos de idade, conduzida em sistema de vaso moderno e espaçamento de 6 x 4 m. O delineamento experimental foi em blocos casualizados, utilizando-se de 15 tratamentos, 8 repetições e 16 frutos por tratamento. Os tratamentos foram os seguintes: T1 - Sacolas de TNT branco de 45 gramaturas por m² (45G/m², fechado; T2 - Sacolas de TNT branco de 45 gramaturas por m² (45G/m²) aberto; T3 - Sacolas de TNT branco de 20 gramaturas por m² (20G/m²) fechado; T4 - Sacolas de TNT branco de 20 gramaturas por m² (20G/m²) aberto; T5 - Sacolas de polipropileno microperfurado transparente (furos de 1mm) fechado; T6 - Sacolas de polipropileno microperfurado transparente (furos de 1mm) aberto; T7 - Sacolas de polipropileno microperfurado transparente (furos de 2mm) fechado; T8 - Sacolas de polipropileno microperfurado transparente (furos de 2mm) aberto; T9 - Sacolas de polietileno microperfurado leitoso (furos de 1mm) fechado; T10 Sacolas de polietileno microperfurado leitoso (furos de 1mm) aberto; T11 Sacolas de polietileno microperfurado leitoso (furos de 2mm) fechado; T12 - Sacolas de polietileno microperfurado leitoso (furos de 2mm) aberto; T13 - Sacolas de papel impermeável fechado; T14 - Sacolas de papel impermeável aberto; T15 - Testemunha (sem ensacamento). As sacolas de TNT (Tecido-não-Tecido) e as de papel impermeável tinham as dimensões de 11,5 x 15,0 cm, e as de polipropileno microperfurado, de 13,0 x 20,0 cm. Os resultados obtidos permitiram concluir que as embalagens de polipropileno transparentes podem ser empregadas para o ensacamento de frutos de pessegueiro, uma vez que as mesmas possibilitam a visualização da coloração dos frutos no momento da colheita, não comprometem o desenvolvimento da coloração dos mesmos e apresentam facilidade no manuseio.

Alterações em propriedades de solo adubado com doses de composto orgânico sob cultivo de bananeira

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

População de plantas, método de colheita e qualidade de sementes de cenoura, cultivar Brasília

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)