963 resultados para Phase development
Resumo:
The current study is a piece from the original project entitled ""Diagnosis of the Developing Program of Artistic Gymnastics in Brazil"". Among other issues discussed in this main project, our objective was to investigate the development of the gymnast who are entering the intensive training and are potential to be representative to national teams. We interviewed 46 coaches from 29 sports institutions in Brazil. Regarding methodology, we used a semi-structured interview and for data treatment we adopted the content analysis proposed by Bardin (2004). We could evidence that coaches have concern regarding many aspects of the children development, and have been trying to equate sports demands with gymnasts characteristics and needs.
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Yttria stabilized tetragonal zirconia (Y-TZP) ceramics were sintered by liquid phase sintering at low temperatures using bioglass as sintering additive. ZrO2-bioglass ceramics were prepared by mixing a ZrO2 stabilized with 3 Mol%Y2O3 and different amounts of bioglass based on 3CaO center dot P2O5-MgO-SiO2 system. Mixtures were compacted by uniaxial cold pressing and sintered in air, at 1200 and 1300 degrees C for 120 min. The influence of the bioglass content on the densification, tetragonal phase stability, bending strength, hardness and fracture toughness was investigated. The ceramics sintered at 1300 degrees C and prepared by addition of 3% of bioglass, exhibited the highest strength of 435 MPa, hardness of 1170 HV and fracture toughness of 6.3 MPa m(1/2). These results are related to the low monoclinic phase content, high relative density and the presence of the thermal residual stress generated between the ZrO2-matrix and bioglass grain boundary, contributing to the activation of the toughening mechanisms. (c) 2007 Elsevier B.V. All rights reserved.
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Ti-rich Ti-Si-B alloys can be considered for structural applications at high temperatures (max. 700 degrees C), however, phase equilibria data is reported only for T = 1250 degrees C. Thus, in this work the phase stability of this system has been evaluated at 700 degrees C. In order to attain equilibrium conditions in shorter time, rapid solidified samples have been prepared and carefully characterized. The microstructural characterization of the produced materials were based on X-ray diffraction (XRD), scanning electron microscopy (SEM-BSE), high resolution transmission electron microscopy (HRTEM), High Temperature X-ray diffraction with Synchrotron radiation (XRDSR) and Differential Scanning Calorimetry (DSC). Amorphous and amorphous with embedded nanocrystals have been observed after rapid solidification from specific alloy compositions. The values of the crystallization temperature (Tx) of the alloys were in the 509-647 degrees C temperature range. After Differential Scanning Calorimetry and High Temperature X-ray Diffraction with Synchrotron radiation, the alloys showed crystalline and basically formed by two or three of the following phases: alpha Ti, Ti(6)Si(2)B; Ti(5)Si(3); Ti(3)Si and TiB. It has been shown the stability of the Ti(3)Si and Ti(6)Si(2)B phases at 700 degrees C and the proposition of an isothermal section at this temperature. (C) 2011 Elsevier B.V. All rights reserved.
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The development of Nb(3)Al and Nb(3)Sn superconductors is of great interest for the applied superconductivity area. These intermetallics composites are obtained normally by heat treatment reactions at high temperature. Processes that allow formation of the superconducting phases at lower temperatures (<1000 degrees C), particularly for Nb(3)Al, are of great interest. The present work studies phase formation and stability of Nb(3)Al and Nb(3)Sn superconducting phases using mechanical alloying (high energy ball milling). Our main objective was to form composites near stoichiometry, which could be transformed into the superconducting phases using low-temperature heat treatments. High purity Nb-Sn and Nb-Al powders were mixed to generate the required superconducting phases (Nb-25at.%Sn and Nb-25at.%Al) in an argon atmosphere glove-box. After milling in a Fritsch mill, the samples were compressed in a hydraulic uniaxial press and encapsulated in evacuated quartz tubes for heat treatment. The compressed and heat treated samples were characterized using X-ray diffractometry. Microstructure and chemical analysis were accomplished using scanning electron microscopy and energy dispersive spectrometry. Nb(3)Al XRD peaks were observed after the sintering at 800 degrees C for the sample milled for 30 h. Nb(3)Sn XRD peaks could be observed even before the heat treatment. (C) 2009 Elsevier B.V. All rights reserved.
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BACKGROUND: The hydrolysis of hemicellulosic material can provide liquor with high xylose concentration (which can be used as a fermentation medium) and phenolic compounds (Phs), potentially immunostimulating compounds. However, these hydrolysates must be detoxified in order to remove the Phs that can act as inhibitors in bioconversions. RESULTS: Aqueous two-phase systems composed of thermoseparating copolymers were used for rice straw hydrolysate detoxification. The hydrolysis process was able to promote chemical breakdown of 85% of the total hemicellulose content, 14% of the cellulose, and 2% of the lignin. The hydrolysate obtained contained 19.7 g L-1 of xylose and several phenolic compounds, such as vanillin, vanillic acid, ferullic acid, etc. The phenolics extraction was studied as a function of copolymer molar mass (1100 g mol(-1), 2000 g mol(-1) and 2800 g mol(-1)), their percentages (from 5% to 50%) and Phs initial concentration. Phenolic compounds extraction of around 80% was obtained under the following conditions: 20% (w/w) and 35% (w/w) copolymer 1100 g mol-1, 35% (w/w) copolymer 2000 g mol(-1) and 35% (w/w) copolymer 2800 g mol(-1) at 25 degrees C. CONCLUSIONS: The results demonstrated the viability of this method for the removal of Phs from rice straw hydrolysate, which has potential uses in bioconversion processes. (c) 2007 Society of Chemical Industry.
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Results of the surface modification of Ti-16Si-4B powder alloy by nitrogen ion implantation are presented, together with the experimental description of the preparation of that powder by high-energy ball milling and hot pressing. The phase structure, chemical composition and morphology of sample surfaces were observed by utilizing X-ray diffractometer (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM). A tribological characterization was carried out with a ball-on-disc tribometer and an SEM. Friction coefficient is compared with the one obtained for Ti-6Al-4V alloy and the wear scars characterized by SEM/EDS (energy dispersive spectroscopy). The concentration profile of the detected elements have been investigated using Auger electron spectroscopy (AES) depth profiling. Our results show that a shallow implanted layer of oxygen and nitrogen ions were obtained at the Ti-16Si -4B alloy surface, sufficient to modify slightly its tribological properties. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.
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In this work, SiC ceramics were liquid phase sintered (LPS), using AIN-Y(2)O(3) as additives, and oxidized at 1400 degrees C in air for up to 120 h. Oxidation was monitored by the weight gain of the samples as function of exposition time and temperature. A parabolic growth of the oxidation layer has been observed and the coefficient of the growth rate has been determined by relating the weight gain and the surface area. The effect of oxidation on strength has been determined by 4-point bending tests. Phase analysis by Xray diffraction and microstructural observation by scanning electron microscopy indicated the formation of a uniform and dense oxidation layer. The elimination of surface flaws and pores and the generation of compressive stresses in the surface resulted in a strength increase of the oxidized samples. (C) 2009 Published by Elsevier Ltd.
Resumo:
As the patient`s treatment progresses, symptoms start to disappear and he or she becomes more familiar with the treatment. The standards in this section focus on the types of elements that need to be considered as the patient progresses from the intensive to the continuation phase of tuberculosis (TB) treatment, leading to less contact with the TB service and a resumption of `normal` activities. Social and psychological as well as physical factors need to be assessed to plan effective care and treatment for the continuation phase. Treatment for TB takes a minimum of 6 months, during which changes to the regimen and personal changes associated with making a recovery can create barriers to continuation of treatment. Lifestyle and other changes that may occur during 6 months of anybody`s life can complicate or be complicated by TB treatment. The patient may move to another location at any point during the course of treatment, in which case it may be necessary to transfer his or her care to another TB management unit. This process needs to be carefully managed to maintain contact with the patient and avoid any break in treatment; this is covered by the third standard in this chapter.
Resumo:
The standards in this chapter focus on maximising the patient`s ability to adhere to the treatment prescribed. Many people are extremely shocked when they are told they have TB, some refuse to accept it and others are relieved to find out what is wrong and that treatment is available. The reaction depends on many factors, including cultural beliefs and values, previous experience and knowledge of the disease. Even though TB is more common among vulnerable groups, it can affect anyone and it is important for patients to be able to discuss their concerns in relation to their own individual context. The cure for TB relies on the patient receiving a full, uninterrupted course of treatment, which can only be achieved if the patient and the health service work together. A system needs to be in place to trace patients who miss their appointments for treatment (late patients). The best success will be achieved through the use of flexible, innovative and individualised approaches. The treatment and care the patient has received will inevitably have an impact on his or her willingness to attend in the future. A well-defined system of late patient tracing is mandatory in all situations. However, when the rates are high (above 10%), any tracing system will be useless without also examining the service as a whole.
Resumo:
Method. Participants were 18 years of age or older, who had been discharged from hospitalisation between 6 months and 1 year before the interview, or who underwent reconstructive surgery during the previous year, or who were under outpatient follow-up awaiting reconstructive surgery. Data were collected by means of semi-structured interviews. Results. Thirty-eight of the 44 participants (86.4%) reported some type of changes associated with the burn injury, the treatment, or both, regarding the following aspects: work, leisure, relationships, religious ties, educational activities and habits (smoking, using alcohol and drugs and dressing style). The data showed a statistically significant association between burns on at least one of the upper limbs (with or without hands) and changes in work. Conclusions. Some of the aspects mentioned by the participants, such as work and leisure activities, need to be further researched in order to improve our understanding of the impact that these changes causes in the person`s life.
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A new simple method to design linear-phase finite impulse response (FIR) digital filters, based on the steepest-descent optimization method, is presented in this paper. Starting from the specifications of the desired frequency response and a maximum approximation error a nearly optimum digital filter is obtained. Tests have shown that this method is alternative to other traditional ones such as Frequency Sampling and Parks-McClellan, mainly when other than brick wall frequency response is required as a desired frequency response. (C) 2011 Elsevier Inc. All rights reserved.
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Considering the difficulties in finding good-quality images for the development and test of computer-aided diagnosis (CAD), this paper presents a public online mammographic images database free for all interested viewers and aimed to help develop and evaluate CAD schemes. The digitalization of the mammographic images is made with suitable contrast and spatial resolution for processing purposes. The broad recuperation system allows the user to search for different images, exams, or patient characteristics. Comparison with other databases currently available has shown that the presented database has a sufficient number of images, is of high quality, and is the only one to include a functional search system.
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In this paper, artificial neural networks are employed in a novel approach to identify harmonic components of single-phase nonlinear load currents, whose amplitude and phase angle are subject to unpredictable changes, even in steady-state. The first six harmonic current components are identified through the variation analysis of waveform characteristics. The effectiveness of this method is tested by applying it to the model of a single-phase active power filter, dedicated to the selective compensation of harmonic current drained by an AC controller. Simulation and experimental results are presented to validate the proposed approach. (C) 2010 Elsevier B. V. All rights reserved.
Resumo:
A phase-only encryption/decryption scheme with the readout based on the zeroth-order phase-contrast technique (ZOPCT), without the use of a phase-changing plate on the Fourier plane of an optical system based on the 4f optical correlator, is proposed. The encryption of a gray-level image is achieved by multiplying the phase distribution obtained directly from the gray-level image by a random phase distribution. The robustness of the encoding is assured by the nonlinearity intrinsic to the proposed phase-contrast method and the random phase distribution used in the encryption process. The experimental system has been implemented with liquid-crystal spatial modulators to generate phase-encrypted masks and a decrypting key. The advantage of this method is the easy scheme to recover the gray-level information from the decrypted phase-only mask applying the ZOPCT. An analysis of this decryption method was performed against brute force attacks. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3223629]
Resumo:
In this paper, a novel wire-mesh sensor based on permittivity (capacitance) measurements is applied to generate images of the phase fraction distribution and investigate the flow of viscous oil and water in a horizontal pipe. Phase fraction values were calculated from the raw data delivered by the wire-mesh sensor using different mixture permittivity models. Furthermore, these data were validated against quick-closing valve measurements. Investigated flow patterns were dispersion of oil in water (Do/w) and dispersion of oil in water and water in oil (Do/w&w/o). The Maxwell-Garnett mixing model is better suited for Dw/o and the logarithmic model for Do/w&w/o flow pattern. Images of the time-averaged cross-sectional oil fraction distribution along with axial slice images were used to visualize and disclose some details of the flow.