Uso da poda e de diferentes diâmetros de alporques sobre o desenvolvimento e o acúmulo de nutrientes de mudas de lichieira

O objetivo deste estudo foi avaliar os efeitos do diâmetro do caule e da poda de alporques sobre o desenvolvimento e o acúmulo de nutrientes em mudas de lichieira cultivadas em substrato. Para isso utilizou-se de alporques da variedade Bengal. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 3 x 2, com oito repetições, sendo três diâmetros do alporque: fino (1,0 ±0,5 cm); médio (2,0 ±0,5 cm) e grosso (3,0 ±0,5 cm), e alporques com e sem poda. As mudas de lichieira foram cultivadas durante 140 dias após o plantio dos alporques. Avaliaram-se a matéria seca das brotações da parte aérea e das raízes, e os teores de macro e micronutrientes. A melhor muda de lichieira foi obtida de alporque com diâmetro grosso, e podado. O alporque de diâmetro médio e fino não-podado, comparado ao podado, proporcionou maior desenvolvimento da muda de lichieira. O alporque com diâmetro grosso proporcionou maior acúmulo de nutrientes na parte aérea e na raiz da muda de lichieira.

Estudo do acoplamento entre superfícies seletivas de frequência assimétricas em estruturas de multicamadas

This work presents the development of new microwaves structures, filters and high gain antenna, through the cascading of frequency selective surfaces, which uses fractals Dürer and Minkowski patches as elements, addition of an element obtained from the combination of the other two simple the cross dipole and the square spiral. Frequency selective surfaces (FSS) includes a large area of Telecommunications and have been widely used due to its low cost, low weight and ability to integrate with others microwaves circuits. They re especially important in several applications, such as airplane, antennas systems, radomes, rockets, missiles, etc. FSS applications in high frequency ranges have been investigated, as well as applications of cascading structures or multi-layer, and active FSS. In this work, we present results for simulated and measured transmission characteristics of cascaded structures (multilayer), aiming to investigate the behavior of the operation in terms of bandwidth, one of the major problems presented by frequency selective surfaces. Comparisons are made with simulated results, obtained using commercial software such as Ansoft DesignerTM v3 and measured results in the laboratory. Finally, some suggestions are presented for future works on this subject

Estudo comparativo de técnicas de cascateamento de superfícies seletivas em frequência

This work presents a theoretical and numerical analysis for the cascading of frequency selective surfaces, which uses rectangular patches and triangular Koch fractals as elements. Two cascading techniques are used to determine the transmission and reflection characteristics. Frequency selective surfaces includes a large area of Telecommunications and have been widely used due to its low cost, low weight and ability to integrate with others microwaves circuits. They re especially important in several applications, such as airplane, antennas systems, radomes, rockets, missiles, etc.. FSS applications in high frequency ranges have been investigated, as well as applications of cascading structures or multi-layer, and active FSS. Furthermore, the analyses uses the microwave circuit theory, with the Floquet harmonics, it allows to obtain the expressions of the scattering parameters of each structure and also of the composed structure of two or more FSS. In this work, numeric results are presented for the transmission characteristics. Comparisons are made with experimental results and simulated results using the commercial software Ansoft Designer® v3. Finally, some suggestions are presented for future works on this subject

Diagnóstico de plasma de cátodo oco: análise da ação de plasma de argônio e Ar-H2 para a deposição de filmes finos de titânio em pós-descarga

Plasma DC hollow cathode has been used for film deposition by sputtering with release of neutral atoms from the cathode. The DC Plasma Ar-H2 hollow cathode currently used in the industry has proven to be effective in cleaning surfaces and thin film deposition when compared to argon plasma. When we wish to avoid the effects of ion bombardment on the substrate discharge, it uses the post-discharge region. Were generated by discharge plasma of argon and hydrogen hollow cathode deposition of thin films of titanium on glass substrate. The optical emission spectroscopy was used for the post-discharge diagnosis. The films formed were analyzed by mechanical profilometry technique. It was observed that in the spectrum of the excitation lines of argon occurred species. There are variations in the rate of deposition of titanium on the glass substrate for different process parameters such as deposition time, distance and discharge working gases. It was noted an increase in intensity of the lines of argon compared with the lines of titanium. Deposition with argon and hydrogen in glass sample observed a higher rate deposition of titanium as more closer the sample was in the discharge

Viabilidade técnica de uma rota não convencional para a produção de leite de cabra em pó em cooperativas do Rio Grande do Norte

Nowadays, Brazil has both the greatest goat herd and the greatest goat milk production of South America. The state of Rio Grande do Norte, located in northeast of Brazil, has an average year production of three thousand cubic meters of goat milk in natura. Part of this milk production is homemade and it comes from small farms, which unite in rural cooperatives created to encourage the production and implementation of industrial processes for preservation and processing of milk. Results presented by literature and obtained from preliminary essays in this thesis show that non conventional dryer of spouted bed with inert particles is able to produce powder milk from in natura milk (cattle or goat), with the same quality of spray dryer, however, operating at low cost. The method of drying in spouted bed consists of injecting milk emulsion on the bed of inert particles gushed by hot air. This emulsion covers the particles with a thin film, which dries and is reduced to powder during the circulation of inerts inside the bed. The powder is dragged by exhaustion air and separated in the cyclone. The friction among particles resulted from the particles circulation, encourages high taxes of shear in the thin film of emulsion, breaking the cohesive forces and making this process possible. Studying the drying process and the powder goat milk production in one unit of spouted bed with inert particles, seeing the development of a low cost technological route for powder milk production is the aim of this thesis. The powder milk produced by this route must attend the local demand of food industries which need an intermediate product to be used as a food ingredient (ice-cream, milk candy). In order to reach this aim, this thesis approaches the aspects related to physical, thermodynamics and physic-chemicals characteristics of goat milk, whose complete data are still inexistent in the literature. The properties of materials are of great importance to the project of any process which involves the operations of transportation of movement, heat and mass quantity, such as the dryers which operate in fluid dynamically active regime, like the spouted bed. It was obtained new data related to the goat milk properties in function of concentration of solids and temperature. It is also important to mention the study developed about the kinetic of solids retention in the bed of inert particles during the drying of goat milk. It was found more adequate processes conditions to the proposed technological route to be implemented in small and micro-industries, with simplifications in the system of milk injection as well as in the form of operation of the dryer. Important data were obtained for a posterior stage of this research which involves the v modeling, simulation, control and optimization of the process. The results obtained in this thesis, in relation to process performance as well as to the quality of produced powder milk validate the proposal of using the spouted bed dryer in the production of powder goat milk

Filmes nanométricos de FeN e ALN crescidos por sputtering e aplicações do efeito peltier

This study will show the capability of the reactive/nonreactive sputtering (dc/rf) technique at low power for the growth of nanometric thin films from magnetic materials (FeN) and widegap semiconductors (AlN), as well as the technological application of the Peltier effect using commercial modules of bismuth telluride (Bi2Te3). Of great technological interest to the high-density magnetic recording industry, the FeN system represents one of the most important magnetic achievements; however, diversity of the phases formed makes it difficult to control its magnetic properties during production of devices. We investigated the variation in these properties using ferromagnetic resonance, MOKE and atomic force microscopy (AFM), as a function of nitrogen concentration in the reactive gas mixture. Aluminum nitride, a component of widegap semiconductors and of considerable interest to the electronic and optoelectronic industry, was grown on nanometric thin film for the first time, with good structural quality by non-reactive rf sputtering of a pure AlN target at low power (≈ 50W). Another finding in this study is that a long deposition time for this material may lead to film contamination by materials adsorbed into deposition chamber walls. Energy-dispersive X-ray (EDX) analysis shows that the presence of magnetic contaminants from previous depositions results in grown AlN semiconductor films exhibiting magnetoresistance with high resistivity. The Peltier effect applied to commercially available compact refrigeration cells, which are efficient for cooling small volumes, was used to manufacture a technologically innovative refrigerated mini wine cooler, for which a patent was duly registered

Fases magnéticas de sistemas nanoestruturados de terras-raras

There is presently a worldwide interest in artificial magnetic systems which guide research activities in universities and companies. Thin films and multilayers have a central role, revealing new magnetic phases which often lead to breakthroughs and new technology standards, never thought otherwise. Surface and confinement effects cause large impact in the magnetic phases of magnetic materials with bulk spatially periodic patterns. New magnetic phases are expected to form in thin film thicknesses comparable to the length of the intrinsic bulk magnetic unit cell. Helimagnetic materials are prototypes in this respect, since the bulk magnetic phases consist in periodic patterns with the length of the helical pitch. In this thesis we study the magnetic phases of thin rare-earth films, with surfaces oriented along the (002) direction. The thesis includes the investigation of the magnetic phases of thin Dy and Ho films, as well as the thermal hysteresis cycles of Dy thin films. The investigation of the thermal hysteresis cycles of thin Dy films has been done in collaboration with the Laboratory of Magnetic Materials of the University of Texas, at Arlington. The theoretical modeling is based on a self-consistent theory developed by the Group of Magnetism of UFRN. Contributions from the first and second neighbors exchange energy, from the anisotropy energy and the Zeeman energy are calculated in a set of nonequivalent magnetic ions, and the equilibrium magnetic phases, from the Curie temperature up to the Nèel temperature, are determined in a self-consistent manner, resulting in a vanishing torque in the magnetic ions at all planes across the thin film. Our results reproduce the known isothermal and iso-field curves of bulk Dy and Ho, and the known spin-slip phases of Ho, and indicate that: (i) the confinement in thin films leads to a new magnetic phase, with alternate helicity, which leads to the measured thermal hysteresis of Dy ultrathin films, with thicknesses ranging from 4 nm to 16 nm; (ii) thin Dy films have anisotropy dominated surface lock-in phases, with alignment of surface spins along the anisotropy easy axis directions, similar to the known spin-slip phases of Ho ( which form in the bulk and are commensurate to the crystal lattice); and (iii) the confinement in thin films change considerably the spin-slip patterns of Ho.

An Intelligent System for Petroleum Well Drilling Cutting Analysis

Cutting analysis is a important and crucial task task to detect and prevent problems during the petroleum well drilling process. Several studies have been developed for drilling inspection, but none of them takes care about analysing the generated cutting at the vibrating shale shakers. Here we proposed a system to analyse the cutting's concentration at the vibrating shale shakers, which can indicate problems during the petroleum well drilling process, such that the collapse of the well borehole walls. Cutting's images are acquired and sent to the data analysis module, which has as the main goal to extract features and to classify frames according to one of three previously classes of cutting's volume. A collection of supervised classifiers were applied in order to allow comparisons about their accuracy and efficiency. We used the Optimum-Path Forest (OPF), Artificial Neural Network using Multi layer Perceptrons (ANN-MLP), Support Vector Machines (SVM) and a Bayesian Classifier (BC) for this task. The first one outperformed all the remaining classifiers. Recall that we are also the first to introduce the OPF classifier in this field of knowledge. Very good results show the robustness of the proposed system, which can be also integrated with other commonly system (Mud-Logging) in order to improve the last one's efficiency.

Synthesis and characterization of Fe(III)-doped ceramic membranes of titanium dioxide and its application in photoelectrocatalysis of a textile dye

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

Material processing by plasma shock wave generated in an inverse Z-pinch plasma expander

The applicability of plasma shock wave for material processing was investigated using modified inverse Z-pinch device. Shock wave expanding speed and plasma spectral analysis were studied using an internal magnetic,probe and spatially collimated light spectroscopy. The material processing capability of the device was shown by many different surface analysis techniques such as AES, IRS, EPM and SEM. The interactions between a plasma shock wave of similar to4x10(6) cm/s speed with a Si substrate surface shows some ion implantation capability using a nitrogen plasma and thin film formation using a methane plasma.

Obtaining of Nanoapatite in Ti-7.5Mo Surface After Nanotube Growth

Titanium and their alloys have been used for biomedical applications due their excellent mechanical properties, corrosion resistance and biocompatibility. However, they are considered bioinerts materials because when they are inserted into the human body they are cannot form a chemical bond with bone. In several studies, the authors have attempted to modify their characteristic with treatments that changes the material surface. The purpose of this work was to evaluate obtaining of nanoapatite after growing of the nanotubes in surface of Ti-7.5Mo alloy. Alloy was obtained from c.p. titanium and molibdenium by using an arc-melting furnace. Ingots were submitted to heat treatment and they were cold worked by swaging. Nanotubes were processed using anodic oxidation of alloy in electrolyte solution. Surfaces were investigated using scanning electron microscope (SEM), FEG-SEM and thin-film x-ray diffraction. The results indicate that nanoapatite coating could form on surface of Ti-7.5Mo experimental alloy after nanotubes growth.

Wear Particle Classifier System Based on an Artificial Neural Network

This paper describes a method of identifying morphological attributes that classify wear particles in relation to the wear process from which they originate and permit the automatic identification without human expertise. The method is based on the use of Multi Layer Perceptron (MLP) for analysis of specific types of microscopic wear particles. The classification of the wear particles was performed according to their morphological attributes of size and aspect ratio, among others. (C) 2010 Journal of Mechanical Engineering. All rights reserved.

Deposição de filmes de ZrO2 modificados sobre substratos metálicos

This work makes use of the Pechini process for synthesis of the solutions and the dip-coating process for the addition of zirconium oxide films pure and doped cerium metal substrates. The metals with ceramic substrates were subjected to severe conditions of salinity. The x-ray fluorescence of the substrate showed a great diversity of chemical elements. The x-ray diffraction of the samples showed the phase of iron substrate because the thickness of nano-thin film. Tests using an LPR probe showed that the film presents with zirconia corrosion independent of film thickness. The substrates of ZrO2-doped ceria showed low chemical attack of the salt in films with less than 15 dives. The results imply that ultrathin films are shown in protecting metallic substrates

Construção de um sistema de caracterização das propriedades de transporte de filmes finos pelo efeito Hall

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

Artificial neural networks: A novel approach to analysing the nutritional ecology of a blowfly species, Chrysomya megacephala

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