Estudo dos óxidos A2B2O7 e ABO3 a base de terras raras, para aplicações térmicas e catalíticas a altas temperaturas

Rare earth elements have recently been involved in a range of advanced technologies like microelectronics, membranes for catalytic conversion and applications in gas sensors. In the family of rare earth elements like cerium can play a key role in such industrial applications. However, the high cost of these materials and the control and efficiencies associated processes required for its use in advanced technologies, are a permanent obstacle to its industrial development. In present study was proposed the creation of phases based on rare earth elements that can be used because of its thermal behavior, ionic conduction and catalytic properties. This way were studied two types of structure (ABO3 and A2B2O7), the basis of rare earths, observing their transport properties of ionic and electronic, as well as their catalytic applications in the treatment of methane. For the process of obtaining the first structure, a new synthesis method based on the use of EDTA citrate mixture was used to develop a precursor, which undergone heat treatment at 950 ° C resulted in the development of submicron phase BaCeO3 powders. The catalytic activity of perovskite begins at 450 ° C to achieve complete conversion at 675 ° C, where at this temperature, the catalytic efficiency of the phase is maximum. The evolution of conductivity with temperature for the perovskite phase revealed a series of electrical changes strongly correlated with structural transitions known in the literature. Finally, we can establish a real correlation between the high catalytic activity observed around the temperature of 650 ° C and increasing the oxygen ionic conductivity. For the second structure, showed clearly that it is possible, through chemical processes optimized to separate the rare earth elements and synthesize a pyrochlore phase TR2Ce2O7 particular formula. This "extracted phase" can be obtained directly at low cost, based on complex systems made of natural minerals and tailings, such as monazite. Moreover, this method is applied to matters of "no cost", which is the case of waste, making a preparation method of phases useful for high technology applications

Análise da adição de resíduo oriundo do tratamento de esgotos em massa cerâmica utilizada para fabricação de telhas

Sludge of Wastewater Treatment Plants (WTPs) disposal is a problem for any municipality, for this reason the amount of sludge production is now a key issue in selecting treatment methods. It is necessary to investigate new applications for this waste type, due to the restrictions imposed by the environmental organs. The raw materials used in the Red Ceramic, are generally very heterogeneous, for this reason, such materials can tolerate the presence of different types of wastes. In Rio Grande do Norte, the roof tiles production corresponds to 60,61% from the total of ceramic units produced. Due to the importance of the ceramic industry of roof tiles for the state, allied to the environmental problem of the sludge disposal, this work had for objective to verify the possibility of the incorporation of sewage sludge in ceramic body used for production of roof tiles. In the research, sludge originating from drying beds of WTP of the Central Campus from UFRN and clays originating from a ceramic industry from Goianinha/RN were used. The raw materials were characterized by techniques of: analysis of particles distribution by diffraction to laser; real density; consistence limits; chemical analysis by X-ray fluorescence; mineralogical analysis by X-ray diffraction; organic matter; and solids content. Five batches of roof tiles were manufactured in the approximate dosages of 2%, 4%, 6%, 8% and 10%. To evaluate the properties of each final product, tests of water absorption, impermeability, bending strength, leachability and solubility were accomplished. The roof tiles manufactured with sludge presented characteristics similar to the roof tiles without sludge in relation to the environmental risk. The results showed that it is possible to use approximately up to 4% of sludge in ceramic bodies for production of roof tiles. However, it is observed that the high amount of organic matter (71%) present in the sludge is shown as factor that limits the sludge incorporation in ceramic bodies, worsening the quality of the roof tiles. It is necessary the use of mixtures of different raw materials under point of view of the granulometry and of the other chemical and mineralogical properties for the obtaining of a satisfactory mass to the production of ceramic roof tiles

As Ciências Espaciais, o saber e o fazer docente no ensino fundamental

This study aims to include topics related to Space Science in elementary education from an experiment that aims to rescue the science teachers in public schools of São Tomé, RN, a taste for experimentation and exploration of advanced technologies. During this research with teachers found that they knew enough about the subject, but this knowledge was restricted to the events disclosed by the media. Regarding scientific knowledge, that same surface, they had many conceptual difficulties which hindered the approach of these topics in their classes. To overcome this difficulty, a workshop was held where teachers had the opportunity to discuss the historical aspect of Space Science, some physical concepts related to it, and the conduct of experiments with PET bottle rockets that recover from the curiosity typical of how the science. The results were outlined in the form of Planning Didactic built by teachers and using themes related to space science, from there, discussing content already provided in the composition of the schools curriculum. Therefore, this work allowed the teachers a minimum training required for them to not only reproduce, but readjusted and build, from this, their own paths in the classroom at the fundamental level

Estudos de sinterização da mistura de pós cerâmicos diatomita-titânia

This work is part of an effort of consolidation of a daily search for powder technology at the Department of Physics of the Universidade Federal do Rio Grande do Norte. This work objective the study and development of new ceramic materials from raw materials abundant at the region. For this, were studied ceramic mixtures of powders from diatomite-titania to aiming at a new ceramic material from powder technology. The experimental work involved a characterization of ceramic powders from a diatomite-titania mixture. The powders obtained were pressed and then parameters like variation of mass, linear shrinkage, activation energy and the mechanism of sintering are studied in function of the time and temperature of sintering, beyond microstructural analysis. The obtained results allow us estimate the optimizing of sintering conditions of this material

Estudo de propriedades elétricas em compostos de Bario

Este trabalho tem como objetivo estudar a influência da adição de diversos aditivos tais como óxido de silício (SiO2), óxido de bismuto (BiO2), óxido de cério (CeO2) e óxido de lantânio (La2O3) nas propriedades elétricas e dielétricas do titanato de bário (BaTiO3) policristalino. As amostras de titanato de bário foram compactadas e sinterizadas no Laboratório de Tecnologia dos Pós, do Departamento de Física da Universidade Federal do Rio Grande do Norte. Foram realizadas medidas de resistividade elétrica e constante dielétrica em função da temperatura, bem como ensaios de difração de raios-X e análise microestrutural através da microscopia eletrônica de varredura. A análise dos resultados permitiu avaliar a influência dos aditivos nas propriedades elétricas e dielétricas, e propor a utilização de cerâmicas eletrônicas a base de titanato de bário com propriedades superiores as do material existente atualmente

Validação do questionário Internacional de Atividade Física (IPAQ) através da acelerometria em idosas

Physical activity is one of the main components of a healthy lifestyle, responsible for many health benefits. Despite being considered important for both disease prevention and health promotion there is high prevalence of sedentary behavior in the elderly population. Questionnaires are practical and feasible instruments for assessing levels of physical activity. However, they may have limitations in older age ranges. Accelerometers, movement sensors that make physical activity data more objective, emerge as reliable measuring devices. Aim: Determine the validity of the International Physical Activity Questionnaire (IPAQ) adapted for elderly with accelerometry in elderly women. Methods: 57 elderly women, with mean age of 66.05 ± 5.98 years who took part in hypertension control and physical activity incentive programs were assessed in relation to objective and subjective measures of physical activity. The accelerometer was used for 07 consecutive days, 24 hours per day before the IPAQ was applied. Data were analyzed using measures of central tendency and dispersion to characterize the sample according to variables collected. To check the validity of the data we used the Spearman correlation test, considering a significance level of p <0.05. Results: With respect to the categories of physical activity obtained by IPAQ, 46.4% developed moderate physical activity, followed by a high (30.3%) and low level (23.2%). There was a negative correlation only between self-reported time spent sitting and time spent on light activities as measured by accelerometry (r = - 0.408; p = 0.003) and mean activity level (counts/min) with physical activity levels evaluated by IPAQ (r = 0.297; p = 0.036). Conclusion: The IPAQ used in elderly women shows moderate to low validity levels according to accelerometry measures. Assessment of sedentary activities exhibited acceptable levels compared to accelerometry; however, moderate (r = 0.096; p > 0.05) to vigorous (r = 0.098; p > 0.05) activities were not correlated, demonstrating the inability of IPAQ to evaluate this type of activity in elderly women

Percepção dos idosos sobre saúde bucal

The assessment of oral health status in elderly patients is essential for the development of specific health policies. The prevalence of oral diseases is high in this population. The self-perception of oral health conditions influences the demand for oral care and quality of life for seniors. The aim of this study was to assess self-perception of oral health status in 100 elderly of both sexes, aged 60 years or older and functionally independent the Basic Health Unit of Felipe Camarão II, Natal, Brazil. For comparison of self-perception data was collected in Bom Pastor, Natal / RN. In this research data were collected a questionnaire grouped into two parts. The first part with the socio-demographic data, subjective and objective condition of oral health and access to the service, the second part GOHAI Index. This index consists of 12 items that make it possible to obtain information involving aspects of chewing, speech, phonation, and self-assessed oral health. The results were subjected to statistical tests of Mann-Whitney and Kruskal-Wallis test (α = 0.05), to identify possible predictors of self-evaluation. As a result, 69% were female, ages ranged from 60 to 86 years, with a median of 65 years. In relation to marital status 48% were married. For the years of study, the sample had an average of 3 years. For the last visit to the dentist, only 27% of seniors had visited the Dentist for less than a year. Regarding the questions about the presence of gingival and dental problems were answered by 46% and 21% respectively. The data on the perception of your teeth and gums, 44%. The index showed GOHAI value for self-perception of 30 points to Felipe Camarão and 28 points for the Bom Pastor, both considered a low perception. We identified predictors of self-rated number of people in the room, participate in any associational activity, there is problems with your teeth and your gums. Concluded a negative self-perception of oral health condition by Gone in both areas, influenced by socioeconomic and cultural issues, although they realize the importance given to oral health, but by the misfortunes of other prominent favored little valuing of oral health

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

Um método semi-automatizado para elicitação de requisitos de acessibilidade Web

In the context of Software Engineering, web accessibility is gaining more room, establishing itself as an important quality attribute. This fact is due to initiatives of institutions such as the W3C (World Wide Web Consortium) and the introduction of norms and laws such as Section 508 that underlie the importance of developing accessible Web sites and applications. Despite these improvements, the lack of web accessibility is still a persistent problem, and could be related to the moment or phase in which this requirement is solved within the development process. From the moment when Web accessibility is generally regarded as a programming problem or treated when the application is already developed entirely. Thus, consider accessibility already during activities of analysis and requirements specification shows itself a strategy to facilitate project progress, avoiding rework in advanced phases of software development because of possible errors, or omissions in the elicitation. The objective of this research is to develop a method and a tool to support requirements elicitation of web accessibility. The strategy for the requirements elicitation of this method is grounded by the Goal-Oriented approach NFR Framework and the use of catalogs NFRs, created based on the guidelines contained in WCAG 2.0 (Web Content Accessibility Guideline) proposed by W3C

Síntese e caracterização de pós Ba(x)Sr(1-x)Co0,8Fe0,2O3- através do método de coprecipitação via oxalato

Ceramic powders based on oxides of perovskite-type structure is of fundamental interest nowadays, since they have important ionic-electronic conductivity in the use of materials with technological applications such as gas sensors, oxygen permeation membranes, catalysts and electrolytes for solid oxide fuel cells (SOFC). The main objective of the project is to develop nanostructured ceramic compounds quaternary-based oxide Barium (Br), Strontium (Sr), Cobalt (Co) and Iron (Fe). In this project were synthesized compounds BaxSr(1-x)Co0, 8Fe0,2O3- (x = 0.2, 0.5 and 0.8) through the oxalate co-precipitation method. The synthesized powders were characterized by thermogravimetric analysis and differential thermal analysis (TGADTA), X-ray diffraction (XRD) with the Rietveld refinement using the software MAUD and scanning electron microscopy (SEM). The results showed that the synthesis technique used was suitable for production of nanostructured ceramic solid solutions. The powders obtained had a crystalline phase with perovskite-type structure. The TGA-DTA results showed that the homogeneous phase of interest was obtained temperature above 1034°C. It was also observed that the heating rate of the calcination process did not affect the elimination of impurities present in the ceramic powder. The variation in the addition of barium dopant promoted changes in the average crystallite size in the nanometer range, the composition being BSCF(5582) obtained the lowest value (179.0nm). The results obtained by oxalate co-precipitation method were compared with those synthesis methods in solid state and EDTA-citrate method

O circuito espacial da indústria de cerâmica vermelha no seridó potiguar

This research has as an empirical universe, the productive territory of red ware in the Seridó region of Rio Grande do Norte. In the last years this territory has gone through a process of appropriation that has been substantially changing the environmental and social dynamism of the place. However, the industry of red ware has been focusing in some areas, mainly, in the county of Parelhas and Carnaúba dos Dantas. From this point of view, the aim of this work consists in analyze the use of these areas by the red ware industry and the transformations occurred with the expansion of the number of industries and the productivity raise, that requires bigger amounts of earthenware and wood, resources that are low in referred territory. As the result of this process, the suitable alternative has been to acquire inputs in other Rio Grande do Norte counties, as well as in Paraíba counties. To reach the proposed objective, the methodology of this work was consisted of bibliographic and empirical research, regarding the occupation that this activity covers in the Seridó region. From the information obtained during the research, it can be stated that the inputs to the production execution in the red ware industry are acquired in the geographic nearby lands. The analysis of the stages of the production(acquisition of raw material, production and commercialization) showed that the activity acts in a continuous area, having as principal consumer market other northeastern states and the state of Pará. The present study revealed that the pottery activity is set as untenable, because of non-stopping use of the argil and wood, resources that are vanishing from the area, which consume causes a many problems such as deforestation and erosion. Besides, the sale of productive lands for the red ware industries makes harder its good use by the familiar agriculturists in the development of agriculture and cattle raising activity, which for many times is the main economic activity of the place. The precariousness reveals in the constant accidents at work, that most of them are neglected by the local authorities, without any penalty to the industries. Therefore, the industry of red ware in Seridó uses the territory as a resource, leaving its environmental problems that my compromise the quality of life of the actual and future generations

Estudo paramétrico da injeção de polímeros em reservatórios de petróleo

Developing an efficient methodology for oil recovery is extremely important . Within the range of enh anced oil recovery, known as EOR, the injection of polymer solutions becomes effective in controlling the mobility of displacing fluid . This method consists of adding polymers to the injection water to increase its viscosity, so that more water diffuses in to the porous medium and increasing the sweep efficiency in the reservoir. This work is studied by numerical simulation , application of the injection polymer solution in a homogeneous reservoir , semisynthetic with similar characteristics to the reservoirs of the Brazilian Northeast , numerical simulations were performed using thermal simulator STARS from CMG (Computer Modelling Group ). The study aimed to analyze the influence of some parameters on the behavior of reservoir oil production, with the response to cumulative production. Simulations were performed to analyze the influence of water injection, polymer solution and alternating injection of water banks and polymer solution, comparing the results for each simulated condition. The primary outcomes were: oil viscosity, percentage of injected polymer, polymer viscosity and flow rate of water injection. The evaluation of the influence of variables consisted of a complete experimental design followed a Pareto analysis for the purpose of pointing out which va riables would be most influential on the response represented b y the cumulative oil production . It was found that all variables significantly influenced the recovery of oil and the injection of polymer solution on an ongoing basis is more efficient for the cumulative production compared to oil recovery by continuous water injection. The primary recovery show ed low levels of oil production , water injection significantly improves the pro duction of oil in the reservoir , but the injection of polymer solution em erges as a new methodology to increase the production of oil, increasing the life of the well and possible reduction of water produced.

Diferenciais de mortalidade adulta por nível de escolaridade no Brasil e regiões

The study of mortality by various differentials has been an important tool to guide public health policies, due to better describing the events of deaths in a population. This research aims to seek disparities in mortality according to educational level, sex and adulthood in large Brazilian regions and consequently for Brazil as a whole. A vast literature has shown that people with more education tend to have lower risk of death. Studies on inequalities in mortality by level of education in Brazil are still very specific and has still known very little about Brazil about mortality according to educational level, due to lack of information about the well-filled school in the records of deaths arising from the Mortality Information System (MIS) of the Ministry of Health. This data source has shown improvement in the coverage of sub reports in the last decade, however, it has still perceived negligence in completing the question regarding schooling of death (about 30% of registered deaths in 2010 to Brazil, Given this scenario, this work contributes to the national literature on the behavior of adult mortality differentials having as proposed, using data from the new variable mortality of the 2010 Census (CD 2010), assuming the characteristics of education of the head the household for deaths occurring in the same. It is therefore considered that the probability of mortality is homogeneous within the household. Events of deaths were corrected only for the records come from households where the head possessed levels of schooling and Instruction Elementary Education No Incomplete and Primary Education and Secondary Education Complete Incomplete through the Generations Extinct Adjusted method. With deaths already corrected, probabilities of death were calculated between 15 and 60 years life, as well as tables by sex and level of education to all regions of Brazil. No que se refere às probabilidades de morte por idade, nas idades entre 15 e 60 anos as maiores probabilidades seguem um gradiente, maior probabilidade para os menos escolarizados. Results corroborate the literature, the more educated the population is, the greater the life expectancy. In all Brazilian regions, life expectancy of the female population is greater than that of men at all levels of schooling. With respect to probabilities of death by age between the ages of 15 and 60 years the most likely follow a gradient, most likely to the least educated. At older ages (from 70 years), this behavior has presented another pattern, the lowest level of education has the lowest odds in the regions, North, Northeast, South and Midwest, except in the Southeast region

Estudo da adição de resíduos de quartzitos para obtenção de grés porcelanato

In States of Paraíba (PB) and Rio Grande do Norte (RN), northeast of Brazil, the most significant deposits of non-metallic industrial minerals are pegmatites, quartzites and granites, which are located in Seridó region. Extraction of clay, quartz, micas and feldspars occurs mainly in the cities of Várzea (PB), OuroBranco (RN) and Parelhas (RN). Mining companies working in the extraction and processing of quartzite generate large volumes of waste containing about 90% SiO2 in their chemical composition coming from quartz that is one of the basic constituents of ceramic mass for the production of ceramic coating. Therefore, this work evaluates the utilization of these wastes on fabrication of high-quality ceramic products, such as porcelain stoneware, in industrial scale. Characterization of raw materials was based on XRF, XRD, GA, TGA and DSC analysis, on samples composed by 57% of feldspar, 37% of argil and 6% of quartzite residues, with 5 different colors (white, gold, pink, green and black). Samples were synthesized in three temperatures, 1150°C, 1200°C and 1250°C, with one hour isotherm and warming-up tax of 10°C/min. After synthesizing, the specimens were submit to physical characterization tests of water absorption, linear shrinkage, apparently porosity, density, flexural strain at three points. The addition of 6% of quartzite residue to ceramic mass provided a final product with technological properties attending technical norms for the production of porcelain stoneware; best results were observed at a temperature of 1200°C. According to the results there was a high iron oxide on black quartzite, being their use in porcelain stoneware discarded by ethic and structural question, because the material fused at 1250°C. All quartzite formulations had low water absorption when synthesized at 1200°C, getting 0.1% to 0.36% without having gone through the atomization process. Besides, flexural strain tests overcame 27 MPa reaching the acceptance limits of the European Directive EN 100, at 1200°C synthesizing. Thus, the use of quartzite residues in ceramic masses poses as great potential for the production of porcelain stoneware.

Integração de projetos no ensino através de BIM: uma abordagem dos cursos de arquitetura e urbanismo da UFRN e da UFPB

The integration between architectural design and structur al systems consi sts, in academic education, one of the main challenges to the architectural design education . Recent studies point to the relevance of the use of computational tools in academic settings as an important strategy for such integration. Although in recent yea rs teaching experience using BIM (BuildingInformationModeling) may be incorporated by the a rchitecture schools , notes the need for further didactic and pedagogical practices that promote the architectural design and structur al integration teaching. This pa per analyzes experiences developed within the UFRN and UFPB, seeking to identify tools, processes and products used, pointing limitations and potentials in subjects taught in these institutions. The research begins with a literature review on teaching BIM and related aspects to the integration of architectural design and stru c tur e . It has been used as data collection techniques in studio the direct observation, the use of questionnaires and interviews with students and teachers, and mixed method, qualitativ e and quantitative analysis . In UFRN, the scope of the Integrated Workshop as a compulsory subject in the curriculum, favors the integration of disciplines studied here as it allows teachers from different disciplines at the same project studio . Regarding the use of BIM form initial users, BIM modelers, able to extract quantitative and automatically speed up production, gaining in quality in the products, however learn the tool and design in parallel cause some difficulties. UFPB, lack of required courses o n BIM, generates lack of knowledge and confidence in using the tool and processes, by most students. Thus we see the need for greater efforts by school to adopt BIM skills and training. There is a greater need for both BIM concept, in order to promote BIM process and consequent better use of tools, and obsolete avoiding impairment of technology, merely a tool. It is considered the inclusion of specific subjects with more advanced BIM skills, through partnerships with engineering degrees and the promotion of trans disciplinary integration favoring the exchange of different cultures from the academic environment.