Síntese e caracterização de ferrita ni-zn pelo método dos precursores poliméricos calcinada por energia de microondas

Magnetic ceramics have been widely investigated, especially with respect to intrinsic and extrinsic characteristics of these materials. Among the magnetic ceramic materials of technological interest, there are the ferrites. On the other hand, the thermal treatment of ceramic materials by microwave energy has offered various advantages such as: optimization of production processes, high heat control, low consumption of time and energy among others. In this work were synthesized powders of Ni-Zn ferrite with compositions Ni1- xZnxFe2O4 (0.25 ≤ x ≤ 0.75 mols) by the polymeric precursor route in two heat treatment conditions, conventional oven and microwave energy at 500, 650, 800 and 950°C and its structural, and morphological imaging. The materials were characterized by thermal analysis (TG/ DSC), X-ray diffraction (XRD), absorption spectroscopy in the infrared (FTIR), scanning electron microscopy (SEM), X-ray spectroscopy and energy dispersive (EDS) and vibrating sample magnetometry (VSM). The results of X-ray diffraction confirmed the formation of ferrite with spinel-type cubic structure. The extrinsic characteristics of the powders obtained by microwave calcination and influence significantly the magnetic behavior of ferrites, showing particles ferrimagnéticas characterized as soft magnetic materials (soft), is of great technological interest. The results obtained led the potential application of microwave energy for calcining powders of Ni-Zn ferrite

Modificação superficial de filmes de poliéster usando plasma a baixa temperatura

A polyester film has a vast application field, due some properties that are inherent of this kind of material such as, good mechanical resistance, chemical resistance to acids and bases and low production cost. However, this material has some limitations as low superficial tension, flat surface, low affinity to dyers, and poor adhesion which impede the use of the same ones for some finality as good wettability. Among the existent techniques to increase the superficial tension, plasma as energy source is the more promising technique, because of their versatility and for not polluting the environment. The plasma surface polymeric modification has been used for many researchers, because it does not affect the environment with toxic agents, the alterations remains only at nanometric layers and this technique shows expressive results. Then, due to its good acceptance, polyester films were treated with oxygen plasma varying the treatment time from 10 to 60 min with an increase of 10 min to each subsequent treatment. Also, the samples were treated with a gas mixture (nitrogen + oxygen) varying the percentage of each gas the mixture from 0 to 100%, the treatment time remaining constant to all treatments (10 min). After plasma treatment the samples were characterized by contact angle, surface tension, Raman spectroscopy, Infrared attenuated total reflection (IR-ATR) and atomic force microscopy, with the aim to study the wettability increase of treated polyester films as its variables. In the (O2/N2) plasma treatment of polyester films can be observed an increase of superficial roughness superior to those treated by O2 plasma. By the other hand, the chemical modification through the implantation of polar groups at the surface is obtained more easily using O2 plasma treatment

Efeitos do tratamento superficial da sílica ativa com soluções de ácidos nítrico e fosfórico em propriedades do concreto

The addition of active silica potentially improves the quality of concrete due to its high reactivity and pore refinement effect. The reactivity of silica is likely related to its charge density. Variations in surface charge alter the reactivity of the material consequently affecting the properties of concrete. The present study aimed at investigating variations in the charge density of silica as a function of acid treatments using nitric or phosphoric acid and different pH values (2.0, 4.0 and 6.0). Effects on concrete properties including slump, mechanical strength, permeability and chloride corrosion were evaluated. To that end, a statistical analysis was carried out and empirical models that correlate studied parameters (pH, acid and cement) with concrete properties were established. The quality of the models was tested by variance analysis. The results revealed that the addition of silica was efficiency in improving the properties of concrete, especially the electrochemical parameters. The addition of silica treated using nitric acid at pH = 4.0 displayed the best cement performance including highest strength, reduced permeability and lowest corrosion current

Supressão do ruído de rolamento superficial utilizando a transformada Curvelet

Among the many types of noise observed in seismic land acquisition there is one produced by surface waves called Ground Roll that is a particular type of Rayleigh wave which characteristics are high amplitude, low frequency and low velocity (generating a cone with high dip). Ground roll contaminates the relevant signals and can mask the relevant information, carried by waves scattered in deeper regions of the geological layers. In this thesis, we will present a method that attenuates the ground roll. The technique consists in to decompose the seismogram in a basis of curvelet functions that are localized in time, in frequency, and also, incorporate an angular orientation. These characteristics allow to construct a curvelet filter that takes in consideration the localization of denoise in scales, times and angles in the seismogram. The method was tested with real data and the results were very good

Desenvolvimento de pastas leves utilizando incorporadores de ar para aplicação em poços de petróleo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Efeito da adição de microfibras de lã de vidro na tenacidade à ruptura de pastas de cimento para poços de petróleo

Although there are a wide variety of additives that act in fresh state, to adjust the properties of cement, there is also a search by additions that improve the tenacity of the cement in the hardened state. This, in turn, can often be increased by inserting fibers, which act on the deflection of microcracks. This study aimed to use a microfiber glass wool (silica-based) as an additive reinforcing the cement matrix, improving the rupture tenacity, in order to prevent the propagation of microcracks in the cement sheath commonly found in oil wells submitted to high temperatures. The fibers were added at different concentrations, 2 to 5% (BWOC) and varied average sizes, grinding for 90 s, 180 s, 300 s, 600 s. The cement slurries were made with a density of 1,90 g/ cm3 (15,6 lb/gal), using Portland cement CPP- Special Class as the hydraulic binder and 40% silica flour. The characterization of the fiber was made by scanning electron microscopy (SEM), particle size by sieving, X-ray fluorescence (XRF), X-ray diffraction (XRD) and thermogravimetry (TG / DTG). Were performed technological tests set by the API (American Petroleum Institute) by rheology, stability, free water, compressive strength, as well as testing rupture energy, elastic modulus and permeability. The characterization results showed good thermal stability of the microfiber glass wool for application in oil wells submitted to steam injection and, also, that from the particle size data, it was possible to suggest that microfibers milled up to 300 s, are ideal to act as reinforcement to the cement slurries. The rheological parameters, there was committal of plastic viscosity when larger lengths were inserted of microfiber (F90). The values obtained by free water and stability were presented according to API. The mechanical properties, the incorporation of microfiber to the cement slurries gave better rupture tenacity, as compared to reference cement slurries. The values of compressive strength, elastic modulus and permeability have been maintained with respect to the reference cement slurries. Thus, cement slurries reinforced with microfiber glass wool can ensure good application for cementing oil wells submitted to steam injection, which requires control of microcracks, due to the thermal gradients

Degradacao termica e catalitica da borra oleosa de Petroleo com materiais nanoestruturados al-mcm-41 e AL-SBA-15

Aiming to reduce and reuse waste oil from oily sludge generated in large volumes by the oil industry, types of nanostructured materials Al-MCM-41 and Al-SBA-15, with ratios of Si / Al = 50, were synthesized , and calcined solids used as catalysts in the degradation of oily sludge thermocatalytic oil from oilfield Canto do Amaro, in the state of Rio Grande do Norte. Samples of nanostructured materials were characterized by thermogravimetric analysis (TG / DTG), X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the infrared Fourier transform (FT-IR) and adsorption nitrogen (BET). The characterization showed that the synthesized materials resulted in a catalyst nanostructure, and ordered pore diameter and surface area according to existing literature. The oily sludge sample was characterized by determining the API gravity and sulfur content and SARA analysis (saturates, aromatics, resins and asphaltenes). The results showed a material equivalent to the average oil with API gravity of 26.1, a low sulfur content and considerable amount of resins and asphaltenes, presented above in the literature. The thermal and catalytic degradation of the oily sludge oil was performed from room temperature to 870 ° C in the ratios of heating of 5, 10 and 20 ° C min-1. The curves generated by TG / DTG showed a more accelerated degradation of oily sludge when it introduced the nanostructured materials. These results were confirmed by activation energy calculated by the method of Flynn-Wall, in the presence of catalysts reduced energy, in particular in the range of cracking, showing the process efficiency, mainly for extraction of lightweight materials of composition of oily sludge, such as diesel and gasoline

A representação social do cuidado no Programa Saúde da Família na cidade do Natal

The aim of this study was to learn about the social representations of the care provided by the Family Health Program (FHP) in the city of Natal, Brazil and determine how these representations guide the daily actions of doctors, dentists, nurses, nurse s assistants and oral health assistants during the work process. In this sense, we used the theoreticalmethodological approach to the Theory of Social Representations. For data collection, we used the following instruments: a two-part questionnaire, where the first part recorded sociodemographic data and the second part was adapted to the free word association technique (FWAT), which was applied to 90 professionals belonging to 18 FHP units. Interviews were also used as collection instruments. These were based on inductive stimuli and on direct observations of 30 of these professionals. After a superficial reading of the material, we constructed a corpus from which ten categories emerged. To analyze FWAT we used lexicographic analysis, combining frequency and the mean order of responses. The interviews and sociodemographic variables were analyzed using content analysis and descriptive statistical analysis, respectively. The study showed that the central nucleus of the social representation in question is composed of the elements attention, receptivity and love, revealing that the subjects have different understandings of the FHP care process and that the knowledge accumulated in this respect is supported by an approximate vision of the meaning of care. However, traditional elements with trivializing connotations about care predominate, which compromises the development of strategies to overcome traditional practices. In the set of analyses, we were able to capture the invariance of a contradiction: on one hand, professionals know and affirm the importance of providing care for FHP patients; on the other, the experience of daily practice translates into the negation of this concept. In this contradictory context, professionals build gradual and successive syntheses that allow them to act and affirm themselves by associating information from their academic formation, structured knowledge acquired in other experiences, values and symbols of their daily routine. Thus, they shape and reshape themselves, according to what is concretely and specifically required, at the same time both plural and multiple. The composition of the central nucleus indicates that any measure that intends to modify attitudes that is, the daily actions of FHP professionals with respect to care must take into account and give priority to the debate about the redefining of the semantic fields of the central nucleus (love/attention/receptivity and humanization), especially those of love and attention

Efetividade do clareamento dentário com peróxido de carbamida a 10% e avaliação dos efeitos adversos sobre o esmalte dentário

The aim of the present study was to assess the effectiveness and adverse effects on dental enamel caused by nightguard vital bleaching with 10% carbamide peroxide. This was accomplished through the interaction of researchers from different areas such as dentistry, materials engineering and physics. Fifty volunteers took part in the doubleblind randomized controlled clinical trial. They were allocated to an experimental group that used Opalescence PF 10% (OPA) and a control group that used a placebo gel (PLA). Fragments of human dental enamel from the vestibular surface of healthy premolars, extracted for orthodontic reasons, were fixed to the vestibular surface of the first upper molars of the volunteers for in situ observation. Bleaching was performed at night for 21 days. The observation periods included Baseline (BL), T0 (21 days), T30 (30 days after treatment) and T180 (180 days after treatment, only for the OPA group). Tooth color was assessed by comparing it with the Vita® scale and by the degree of satisfaction expressed by the volunteer. We also assessed adverse clinical effects, dental sensitivity and gingival bleeding. The study of adverse effects on enamel was conducted in vivo and in situ, using the DIAGNOdent® laser fluorescence device to detect mineral loss. Scanning electron microscopy (SEM) was used to check for superficial morphological alterations, energy dispersive spectrophotometry (EDS) to semiquantitatively assess chemical composition using the Ca/P ratio, and the x-ray diffraction (XRD) technique to observe alterations in enamel microstructure. The results showed that nightguard vital bleaching with 10% carbamide peroxide was effective in 96% of the cases, versus 8% for the PLA group. Dental sensitivity was present in 36% (9/25) of the cases. There was no significant association between gingival bleeding and the type of gel used (p = 1.00). In vivo laser fluorescence analysis showed no difference in values for the control group, whereas in the OPA group there was a statistically significant difference between baseline values in relation to the subsequent periods (p<0.01), with lower mean values for post-bleaching times. There was a significant difference between the groups for times T0 and T30. Micrographic analysis showed no enamel surface alterations related to the treatment performed. No significant alteration in Ca/P ratio was observed in the OPA group (p = 0.624) or in the PLA group (p = 0.462) for each of the observation periods, nor between the groups studied (p=0.102). The XRD pattern for both groups showed the presence of three-phase Hydroxyapatite according to JCPDS files (9-0432[Ca5(PO4)3(OH)], 18-0303[Ca3(PO4)2.xH2O] and 25-0166[Ca5(PO4)3(OH, Cl, F)]). No other peak associated to other phases was found, independent of the group analyzed, which reveals there was no disappearance, nucleation or phase transformation. Neither was there any alteration in peak pattern location. With the methodology and protocol used in this study, nightguard vital bleaching with 10% carbamide peroxide proved to be an effective and safe procedure for dental enamel

Tempo livre de lazer e composição corporal de escolares do meio-oeste catarinense

The aim of this study was to investigate the relationship between free time for leisure and body composition of students in the crucial ninth year. (N = 228) of towns in the Midwest catarinense. We used the Adolescent Behavior Questionnaire of Santa Catarina (COMPAC) to assess lifestyle, considering that Active schoolchildren during the week, accumulated 300 or more minutes of moderate or vigorous physical activity (MVPA). Were used the time to 2 hours or more / day to determine the time of excessive use of TV and computer video game. To analyze body composition were used two criteria: the Body Mass Index (BMI) and sum of skinfolds (EDC). It was observed a proportion of 67.3% of girls and 68.7% of boys assets and more than 98% of students were using excessive TV time, computer and video game. In the classification by EDC, most of the boys showed great or low levels of body composition, while more than half of girls were classified at higher levels. As for BMI, most boys and girls had not overweight. Significant difference in the comparison of total minutes per week of MVPA reported between the groups, the second criterion of EDC and BMI for girls but not for BMI in boys. It is concluded that students with higher accumulation in minutes of MVPA showed better body composition indicators, but no significant difference was found when compared active groups with inactive, according to criteria used.

Nanopartíulas de magnetita com oxacilina obtida por moagem de alta energia para aplicações biomédicas

The drug targeting has been the subject of extensive studies in order to develop site-specific treatments that minimize side effects and become more effective anticancer therapy. Despite considerable interest in this class, drugs like antibiotics also have limitations, and have been neglected. Using new pharmaceutical technologies, the use of magnetic vectors appear as promising candidate for drug delivery systems in several studies. Small magnetic particles bound to the drug of interest can be modulated according to the orientation of a magnet outside the body, locating and holding in a specific site. In this work, we propose the use of High Energy Milling (HEM) for synthesis of a magnetic vector with characteristics suitable for biomedical applications by intravenous administration, and for the formation of an oxacillin-carrier complex to obtain a system for treating infections caused by Staphylococcus aureus. The results of the variation of milling time showed that the size and structural properties of the formed material change with increasing milling time, and in 60 hours we found the sample closest to the ideal conditions of the material. The vector-drug system was studied in terms of structural stability and antimicrobial activity after the milling process, which revealed the integrity of the oxacillin molecule and its bactericidal action on cultures of Staphylococcus aureus ATCC

O princípio constitucional da livre concorrência como instrumento de desenvolvimento socioeconômico

The freedom of concurrence, firstly conceived as a simple market fundament in productive systems that recognized the productive forces freedom of action, appears as a clear instrument of protection and fomentation of the market, recognizing the importance of the simultaneous existence of various economic forces such the proper capitalism reason of constitution. It has, thus, a directly role linked to the fundamental idea that the market and its productive forces needed of a protection against itself, because it exists inside the market situations and circumstances, provoked or not, that could prejudice and even annihilate the its existence and functioning, whilst a complex role of productive forces presents at all economic creation space. It was the primacy of the classic liberalism, the first phase of the capitalism. The Constitutions, in that historic moment, did not proclaim any interference at the economic scenario, simply because it recognized the existence of an economic freedom prepared to justify and guarantee the market forces, with its own rules. Based on the structural changes that occurred at the following historic moments, inside the constitutionally recognized capitalism, it was verified changes in the ambit of treatment of the freedom of concurrence principle that, in a progressive way, passes to present a configuration more concerned with socialist and developing ideas, as long as not only a market guarantee. It emerges a freedom of concurrence which aim is instrumental, in relation to its objectives and constitutional direction as a role, and not anymore stagnant and with isolated treatment, in special at the constitutional systems the present s clear aspects of social interventions and guarantor of fundamental rights more extensive and harmonious. That change is located at a space of state actuation much more ample and juridical important, this time comprehending the necessity of managing the productive scenario aiming to reach a national social and economic development effectively guarantor of fundamental rights for all citizens. Those Constitutions take as point of starting that the social and economic development, and not only anymore the economic growth, is the effective way for concretization of these rights. In that way it needs to be observed and crystallized by political and juridical tools that respect the ideological fundamental spirit of the Constitutional Charters. In that scenario that seeks for solutions of rights accomplishment, in special the social rights, the constitutional principle of freedom of concurrence has been seen as an instrument for reaching bigger values and directives, such as the social justice, which only can be real at a State that can implement a comprehensive and permanent social and economic development. The freedom of concurrence tries to valorize and defend something larger and consonant to the political values expressed in the Constitutional Charters with social character, which is the right to a social and economical sustainable development, guarantor of more clear and compromised collective benefits with social justice. The origin of that constitutional imposition is not only supported by vague orientations of the economic space, but as integrated to it, with basis formed of normative and principles posted and prepared to produce effects at the proper reason of the Constitution

Paradigma constitucional brasileiro da livre concorrência e da defesa do consumidor face às estruturas de poder no mercado

The Federal Constitution of 1988, when taking care of the economical order, denotes special concern in the abuses of the economical power and the disloyal competition. The mark to mediate of all this is, in fact, the defense and the consumer's protection, once this is final addressee of whatever if it puts at the consumption market. The coming of the Law 8.078/90, Code of Protection and Defense of the Consumer, inaugurates a time of effective concern with the homogeneous individual interests originating from of the consumption relationships. In this point, the focus of main to face of the present work lives, in other words, the protection of the right to the individual property, especially manifests in the exercise of the trade freedom that keeps direct relationship with the respective social function the one that is destined. The code of the consumer's defense doesn't just take care of this, but also of the other star of the relationships of the consumption. When affirming in the interruption VI of the art. 4th that the national politics of those relationships, finds ballast in the prohibition and repression efficient of all of the abuses committed in the consumption relationships, keeping inherent relationship-causality in the economical order, sculpted for the article 170 in the Constitution of 1988. In the generic plan, the mark of the present work is to question concerning the limits of the trade freedom and previsible collisions with protection norms and the consumer's defense, as well as factual convergences of those small systems, especially in what he/she refers to the innate interests to the suppliers. In the specific plan, we aspirated to identify the protection device-commands to the actors of the trade relationship, capable to guarantee the free competition in a global economy of market, seeking especially the Well-being, for soon afterwards, in an analytical perspective, to discover the possible applications that it holds the Federal Constitution, in headquarters of economical freedoms. It was observed that the consumer today doesn't need only of laws that their needs, fruit of the vulnerability that it is him/her meditate innate. He/she lacks, yes, of effective mechanisms that prevent lesions that can be them impinged by the suppliers at the time in that you/they are useful to repair the damages when happened, punishing the author of the damage

O direito social fundamental de acesso à energia elétrica e a atuação estatal

Electrical energy today is an essential element in the life of any human being. Through the access to electrical energy it is possible to enjoy dignified conditions of life, having in mind the possibility of making use of minimal material conditions of life. The lack of access to electricity is directly linked to poverty and degrading conditions of life, in which are some communities in Brazil, especially the more isolated from urban centers. Access to the electric service is a determining factor for the preservation of human dignity, constitutional principle inscribe in the art.1 of the Federal Constitution, and the promotion of development, being a right of everyone and a duty of the State to promote universal access. For that reason, focuses mainly on the analysis of their setting as a fundamental social right and its importance for national development. For this, the theoretical and descriptive method was used, with normative and literary analysis, in particular the Constitution of 1988. This study also discusses the form of action of the State in the energy sector, to give effect to the fundamental social right of access to electricity, the characteristics of public service and the principles that guide it, in addition to the role of public policies in universalization of access, in particular the analysis of the Program Luz para Todos, and the function of regulation in the implementation of these policies and the provision of adequate public services.

O dumping ambiental no setor sucroalcooleiro à luz do princípio da livre concorrência

The goal of this study is to investigate about the existence or absence of environmental dumping in the production of fuel ethanol in Brazil, as well as identifying the reasons why the figure of ecological dumping is pernicious to the principles enumerated in constitutional economic order, in particular the principle of free competition. In the twenty-first century environmental issues gained momentum and importance in these terms, which was seen as a mere fallacy given the concern of governments of various countries, after all, environmental protection shows up as the only means of bringing about the maintenance of life at planet. Indeed, it is essential to halt the drastic effects of climate change, and think fast and efficient solutions. Undoubtedly, the contemporary requirements that resulted in the transition to a new economy brings with it the duty of enterprise search for sustainability, and this behavior can not be passive, otherwise it is imperative to work hard and incessant economic agents, even if initially costs are high, this step will ensure a production accountable, transparent and free from accusations of environmental degradation. It is also intended to study the importance of the sector not only as a source of economic growth, but mainly, its contribution to national development, without forgetting that this is devoted in the Constitution of 1988 as one of the objectives of the Federative Republic of Brazil. In fact, the criticism most common perceptions about the production of biofuels, said the interests of the countries producing them in large scale, will eventually generate a exhaustion of soil and a significant increase in food prices. However, the ethanol produced in Brazil is unique in that it is produced from cane sugar, a product is not intended for human or animal, not to mention that the recovery of land just to the rotation with the planting other cultures. It is expected that environmental certifications are useful to demonstrate the quality of ethanol for export and to refute unfounded criticism. Finally, this study will be analyzed further solutions for the plants to develop an economic activity without damaging the environment and in compliance with Brazilian law