Síntese e caracterização de ferritas de níquel dopadas com cobalto e efeito da substituição nas suas propriedades magnéticas

The ferrite composition Ni1 - xCoxFe2O4 (0 ≤ x ≤ 0.75) were obtained by the method of microwave assisted synthesis and had their structural and magnetic properties evaluated due to the effect of the substitution of Ni by Co. The compounds were prepared: according to the concept of chemical propellants and heated in the microwave oven with power 7000kw. The synthesized material was characterized by absorption spectroscopy in the infrared (FTIR), Xray diffraction (XRD) using the Rietveld refinement, specific surface area (BET) , scanning electron microscopy (SEM) with aid of energy dispersive analysis (EDS) and magnetic measurements (MAV). The results obtained from these techniques confirmed the feasibility of the method of synthesis employed to obtain the desired spinel structure, the ferrite, nickel ferrite as for nickel doped with cobalt. The results from XRD refinement ally showed the formation of secondary phases concerning stages α - Fe2O3, FeO, (FeCo)O e Ni0. On the other hand, there is an increase in crystallite size with the increase of cobalt in systems, resulting in an increased crystallinity. The results showed that the BET systems showed a reduction in specific surface area with the increase of cobalt and from the SEM, the formation of irregular porous blocks and that the concentration of cobalt decreased the agglomerative state of the system. The magnetic ferrites studied showed different characteristics according to the amount of dopant used, ranging from a very soft magnetic material (easy magnetization and demagnetization ) - for the system without cobalt - a magnetic material with a little stiffer behavior - for systems containing cobalt. The values of the coercive field increased with the increasing growth of cobalt, and the values of saturation magnetization and remanence increased up to x = 0,25 and then reduced. The different magnetic characteristics presented by the systems according to the amount of dopant used, allows the use of these materials as intermediates magnetic

A assistência estudantil e as cotas sociais nas universidades estaduais do nordeste: as faces do acesso ao direito

This paper discusses about the higher education in Brazilian society highlighting the struggle of the working class, as concerning the access to public universities, as well as highlights the contradictions implicit in social quotas adopted by Higher Education Institutions (HEIs) . The aim of this paper is on presenting the analysis of student assistance of the state universities in the Northeast that adopt quotas as social criteria of access for its students , presenting investigative locus as the following universities : UERN , UEPB , UPE and UNEAL . The paper presents the results of a qualitative study , based on a documentary analysis , based on dialectical and historical materialism in which she performed the reading of data from the following analytical categories: Higher Education, Social Quotas and Student Assistance. As main results, it is emphasized that the implementation of quotas as a means of access to higher education was not decisive for the form of planning and implementation of student assistance the university investigated; latent heterogeneity is that universities deal with actions to support student residence. And it is this heterogeneity and the variation in the conduct and understanding of student assistance , reflecting the lack of prioritization with the actions of the context of HEIs ; support programs are to stay focused on central campuses which are located the administrative offices of the universities, penalizing students enrolled in advanced units; also highlight that there is no link between the programs and projects related to student assistance with actions related to teaching, research and extension in universities investigated , which ultimately characterize the student assistance as an isolated action and punctual

Análise da degradação ambiental das áreas de preservação permanente localizadas no estuário do rio Ceará-mirim/RN

The purpose of this paper is to identify and analyze the main environmental impacts taking place in the permanent preservation areas located in the Ceará-Mirim River estuary/RN and its surrounding areas. For that, the study was divided in two chapters, structured in the shape of a scientific paper. The first is a theoretical proposition on the occupation of the APPs in light of the discussion of the geographic space and the sustainability of the development, where a bibliographical review was made emphasizing the production of the geographic space, the sustainability of the development and the permanent preservation areas. In the second chapter, from a systemic approach, geoprocessing techniques and the adaptation of the Pressure-State- Response Indicators System were used, the latter being developed by the Organization for Economic Co-operation and Development OECD. Therefore, from the methodological approaches used, it's been observed that the use of permanent preservation areas for purposes other than those determined in the legislation and, mainly guided by capitalist interests, leads to the environmental degradation of these areas, fact which has been confirmed in the empiric study conducted in the second chapter, where it was possible to identify a series of environmental impacts such as: deforestation of mangrove and riparian vegetation for carciniculture implantation, the devastation of dune areas caused by the urban expansion in the coastal stretch and siltation of fluvial channel

Metodologia para gerenciamento de projetos em tecnologia da informação baseada no guia PMBOK: um estudo de caso na Secretaria de Estado da Saúde Pública do Rio Grande do Norte

Nowadays the search for growth makes organizations seeking competitive advantages, project management shares this goal, through techniques that assist in the search for an improved management of the various fields of knowledge through a design methodology. The world is driven by projects and the search for ways to better manage activities such as time, cost and term towards the success of a particular project is something constant. A major contribution that IT can make to the health sector is the support for the management area. IT can integrate processes, optimize the interconnection between the various sectors, make hospitals have access to inside information of good quality, as well as support in the healthcare area, sharing pictures, uniting the various aspects of nursing and nursing service. The major challenge faced by the SESAP Information Technology sector at present is in project management in IT , which does not exist makes investments in the area are increasingly difficult due to this deficiency in management develop their own systems without cost additional to the State. This study seeks to build and strengthen the Project Management within the Department of Health through the implementation of a project office that will manage the final result of this work methodology based on PMBOK, and still show the functionality applied to development the state Hospital Management System that will later be installed on all Regional Health Units and proposing measures for the sustainability and development of the sector amid the difficulties of the current public service. Such action will result in a savings of more than R$ 107,000.00 (one hundred seven thousand) regarding spending private software currently used by the assignment of invested by the State of Rio Grande do Norte user licenses, representing more than 5 % of the total budget of the State Department of Public Health of the State

Resolução em tomografia de tempo de trânsito poço-a-poço: a dependência da iluminação

The key aspect limiting resolution in crosswell traveltime tomography is illumination, a well known result but not as well exemplified. Resolution in the 2D case is revisited using a simple geometric approach based on the angular aperture distribution and the Radon Transform properties. Analitically it is shown that if an interface has dips contained in the angular aperture limits in all points, it is correctly imaged in the tomogram. By inversion of synthetic data this result is confirmed and it is also evidenced that isolated artifacts might be present when the dip is near the illumination limit. In the inverse sense, however, if an interface is interpretable from a tomogram, even an aproximately horizontal interface, there is no guarantee that it corresponds to a true interface. Similarly, if a body is present in the interwell region it is diffusely imaged in the tomogram, but its interfaces - particularly vertical edges - can not be resolved and additional artifacts might be present. Again, in the inverse sense, there is no guarantee that an isolated anomaly corresponds to a true anomalous body because this anomaly can also be an artifact. Jointly, these results state the dilemma of ill-posed inverse problems: absence of guarantee of correspondence to the true distribution. The limitations due to illumination may not be solved by the use of mathematical constraints. It is shown that crosswell tomograms derived by the use of sparsity constraints, using both Discrete Cosine Transform and Daubechies bases, basically reproduces the same features seen in tomograms obtained with the classic smoothness constraint. Interpretation must be done always taking in consideration the a priori information and the particular limitations due to illumination. An example of interpreting a real data survey in this context is also presented.

Resolução em tomografia de tempo de trânsito poço-a-poço: a dependência da iluminação

The key aspect limiting resolution in crosswell traveltime tomography is illumination, a well known result but not as well exemplified. Resolution in the 2D case is revisited using a simple geometric approach based on the angular aperture distribution and the Radon Transform properties. Analitically it is shown that if an interface has dips contained in the angular aperture limits in all points, it is correctly imaged in the tomogram. By inversion of synthetic data this result is confirmed and it is also evidenced that isolated artifacts might be present when the dip is near the illumination limit. In the inverse sense, however, if an interface is interpretable from a tomogram, even an aproximately horizontal interface, there is no guarantee that it corresponds to a true interface. Similarly, if a body is present in the interwell region it is diffusely imaged in the tomogram, but its interfaces - particularly vertical edges - can not be resolved and additional artifacts might be present. Again, in the inverse sense, there is no guarantee that an isolated anomaly corresponds to a true anomalous body because this anomaly can also be an artifact. Jointly, these results state the dilemma of ill-posed inverse problems: absence of guarantee of correspondence to the true distribution. The limitations due to illumination may not be solved by the use of mathematical constraints. It is shown that crosswell tomograms derived by the use of sparsity constraints, using both Discrete Cosine Transform and Daubechies bases, basically reproduces the same features seen in tomograms obtained with the classic smoothness constraint. Interpretation must be done always taking in consideration the a priori information and the particular limitations due to illumination. An example of interpreting a real data survey in this context is also presented.