77 resultados para eletrônicos
Resumo:
Aborda o tratamento técnico informacional de discos sonoros na Biblioteca Especializada em Música Pe. Jaime Diniz, da Universidade Federal do Rio Grande do Norte. Caracteriza os discos sonoros enquanto suporte informacional. Relata as dificuldades encontradas no processo de tratamento da informação musical em materiais especiais. Objetiva estabelecer diretrizes para a análise, representação e organização do acervo de discos sonoros. Utiliza a pesquisa bibliográfica em fontes impressas e eletrônicas para o suporte teórico, tendo como metodologia o estudo de caso. Conclui que as regras e padrões para o tratamento técnico da informação no campo da Biblioteconomia podem sofrer adaptações para melhor representar o conteúdo musical dos discos sonoros, considerando a necessidade do profissional da informação em aperfeiçoar seus conhecimentos em música.
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This research aims at studying the use of greeting cards, here understood as a literacy practice widely used in American society of the United States. In American culture, these cards become sources of information and memory about people‟s cycles of life, their experiences and their bonds of sociability enabled by means of the senses that the image and the word comprise. The main purpose of this work is to describe how this literacy practice occurs in American society. Theoretically, this research is based on studies of literacy (BARTON, HAMILTON, 1998; BAYHAM, 1995; HAMILTON, 2000; STREET, 1981, 1984, 1985, 1993, 2003), the contributions of social semiotics, associated with systemic-functional grammar (HALLIDAY; HASAN 1978, 1985, HALLIDAY, 1994, HALLIDAY; MATTHIESSEN, 2004), and the grammar of visual design (KRESS; LEITE-GARCIA, VAN LEEUWEN, 1997, 2004, 2006; KRESS; MATTHIESSEN, 2004). Methodologically, it is a study that falls within the qualitative paradigm of interpretative character, which adopts ethnographic tools in data generation. From this perspective, it makes use of “looking and asking” techniques (ERICKSON, 1986, p. 119), complemented by the technique of "registering", proposed by Paz (2008). The corpus comprises 104 printed cards, provided by users of this cultural artifact, from which we selected 24, and 11 e-cards, extracted from the internet, as well as verbalizations obtained by applying a questionnaire prepared with open questions asked in order to gather information about the perceptions and actions of these cards users with respect to this literacy practice. Data analysis reveals cultural, economic and social aspects of this practice and the belief that literacy practice of using printed greeting cards, despite the existence of virtual alternatives, is still very fruitful in American society. The study also allows users to comprehend that the cardholders position themselves and construct identities that are expressed in verbal and visual interaction in order to achieve the desired effect. As a result, it is understood that greeting cards are not unintentional, but loaded with ideology and power relations, among other aspects that are constitutive of them.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
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The main objective of the present work is to contribute to the development of the coordination chemistry of macromolecules such as resorcinarene with the synthesis and characterization of new copper complexes with chloride, vanillin and resorcinarene binders, all coordinated to phenanthroline, a biologically active molecule with important properties in biological systems. The complex [(Cu(phen))4(resvan)], was synthesized from the direct reaction of the metals with resorcinarene and generates several possibilities for coordination, which hinders its characterization. Therefore, in order to limit the coordination sites of the ligand, the complex [(Cu(phen))4(resvan)]Cl4 was formed from a new synthetic methodology. The complex cis-[Cu(phen)Cl2], cis-[Cu(phen)(van)]Cl, [(Cu(phen))4(resvan)] and [(Cu(phen))4(resvan)]Cl4 were characterized by spectroscopic techniques such as IR, UV-vis and EPR. By using infrared it has been possible to demonstrate the presence of the phenanthroline ligand in the synthesized complexes, and vanillin in the complex cis- [Cu(phen)(van)]Cl and resvan ligand in the complex [(Cu(phen))4(resvan)], besides this indicating the formation of resorcinarene in the complex [(Cu(phen))4(resvan)]Cl4. The electronic spectra of these coordination compounds indicated the presence of the phenanthroline ligand, by its intense bands in the ultraviolet region. For the complex cis- [Cu(phen)(van)]Cl it still indicated the presence of the ligand vanillin based on intraligand bands of vanillin and charge transfer, LMCT. Furthermore, the spectra showed d-d bands, confirming the formation of metal compounds. The amount of copper atoms present in the complex [(Cu(phen))4(resvan)]Cl4 was estimated from a comparative analysis of the absorbances of solutions of the same concentration of [(Cu(phen))4(resvan)]Cl4 and cis- [Cu(phen)(van)]Cl, which indicates that these compounds have copper atoms in the ratio 4:1. The EPR spectra of the complex cis-[Cu(phen)Cl2], cis-[Cu(phen)(van)]Cl and [(Cu(phen))4(resvan)]Cl4 showed axial profiles, while the complex [(Cu(phen))4(resvan)] showed of axial and rhombic profiles, indicating a change in the symmetry of the Cu (II) to this complex environment. The binders vanillin and resvan underwent biological assays with satisfactory results, both exhibited antioxidant activity and low toxicity, as well vanillin present antitoxoplásmico character.
Estudo teórico de intermediários tetraédricos acidez / basicidade e estereosseletividade enzimáticos
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The present work aimed first, the theoretical study of tetrahedral intermediate stability formed from carbonyl addition reactions using the second (MP2) and third (MP3) order Møller–Plesset perturbation theory. Linear correlations between electronic energy difference of reactions with Wiberg Indexes and C-O bond lengths were obtained, and was observed that the stability of adducts formed depends directly of electronic density involved between these atoms. The knowing of electronic parameters of these structures has an important hole due to the large use on reactions that in his course forms this tetrahedral intermediate. Employing the ONIOM (B3LYP:AMBER) methodology, was evaluated the stereoselectivity of a enzymatic reaction between CAL B enzyme and a long chain ester. In this study, were obtained the electronic energies of ground state and intermediate state of transesterification rate-determing step from two possible proquirals faces Re and Si. The objective was study the enantioselectivity of CAL B and rationalizes it using quantum theory of atoms in molecules (QTAIM). A theoretical study employing inorganic compounds was performed using ab initio CBS-QB3 method aiming to find a link between thermodynamic and equilibrium involving acids and bases. The results observed showed an excellent relationship between difference in Gibbs free energy, ΔG of acid dissociation reaction and ΔG of hydrolysis reaction of the corresponding conjugate base. It was also observed, a relationship between ΔG of hydrolysis reaction of conjugate acids and their corresponding atomic radius showing that stability plays an important role in hydrolysis reactions. The importance of solvation in acid/base behavior when compared to theoretical and experimental ΔG´s also was evaluated.
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The goal set for this work was to synthesize and to characterize new iron and copper complexes with the Schiff base 3-MeOsalen and ligands of biological relevance, whose formulas are [Fe(3-MeOsalen)NO2], [Fe(3-MeOsalen)(etil2-dtc)], [Fe(3-MeOsalen)NO] and Na[Cu(3-MeOsalen)NO2]. The compounds were characterized by vibrational spectroscopy in the infrared region (IV) and Electronic spectroscopy in the ultraviolet and visible region (Uv-Vis). From the analysis of infrared spectra, they proved to formation of precursor complexes, as evidenced by changes in the vibrationals frequencies ν(C=N) e ν(C-O) and the emergence of vibrationals modes metal-oxygen and metal-nitrogen. For nitro complexes of iron and copper were observed ν(NO2)ass around 1300 cm-1 e ν(NO2)sim in 1271 cm-1 , indicating that the coordination is done via the nitrogen atom. The complex spectrum [Fe(3-MeOsalen)(etil2-dtc)] exhibited two bands, the ν(C-NR2) in 1508 cm-1 e ν(C-S) in 997 cm-1 , the relevant vibrational modes of coordinating ligand in the bidentate form. For the complex [Fe(3-MeOsalen)NO] was observed a new intense band in 1670 cm-1 related to the ν(NO). With the electronic spectra, the formation of complexes was evidenced by shifts of bands intraligands transitions and the emergence of new bands such as LMCT (p Cl- d* Fe3+) in [Fe(3-MeOsalen)Cl] and the d-d in [Cu(3-MeOsalen)H2O]. As for the [Fe(3-MeOsalen)NO2] has highlighted the absence of LMCT band present in the precursor complex as for the [Cu(3-MeOsalen)NO2] found that the displacement of the band hipsocrômico d-d on 28 nm. The electronic spectrum of [Fe(3-MeOsalen)(etil2-dtc)] presented LMCT band shifts and changes in intraligantes transitions. With regard to [Fe(3-MeOsalen)NO], revealed a more energetic transitions intraligands regions from the strong character π receiver NO and MLCT band of transition dπFe(II)π*(NO).
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Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq
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Composite NiO-C0.9Gd0.1O1.95 (NiO-GDC), one of the materials most used for the manufacture of anodes of Cells Solid Oxide Fuel (SOFC) currently, were obtained by a chemical route which consists in mixing the precursor solution of NiO and CGO phases obtained previously by the Pechini method. The nanopowders as-obtained were characterized by thermal analysis techniques (thermogravimetry and Differential Scanning Calorimetry) and calcined materials were evaluated by X-ray diffraction (XRD). Samples sintered between 1400 and 1500 ° C for 4 h were characterized by Archimedes method. The effects of the composition on the microstructure and electrical properties (conductivity and activation energy) of the composites sintered at 1500 ° C were investigated by electron microscopy and impedance spectroscopy (between 300 and 650 ° C in air). The refinement of the XRD data indicated that the powders are ultrafine and the crystallite size of the CGO phase decreases with increasing content of NiO. Similarly, the crystallite of the NiO phase tends to decrease with increasing concentration of CGO, especially above 50 wt % CGO. Analysis by Archimedes shows a variation in relative density due to the NiO content. Densities above 95% were obtained in samples containing from 50 wt % NiO and sintered between 1450 and 1500 °C. The results of microscopy and impedance spectroscopy indicate that from 30-40 wt.% NiO there is an increase in the number of contacts NiO - NiO, activating the electronic conduction mechanism which governs the process of conducting at low temperatures (300 - 500 °C). On the other hand, with increasing the measuring temperature the mobility of oxygen vacancies becomes larger than that of the electronic holes of NiO, as a result, the high temperature conductivity (500-650 ° C) in composites containing up to 30-40 wt.% of NiO is lower than that of CGO. Variations in activation energy confirm change of conduction mechanism with the increase of the NiO content. The composite containing 50 wt. % of each phase shows conductivity of 19 mS/cm at 650 °C (slightly higher than 13 mS/cm found for CGO) and activation energy of 0.49 eV.
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This thesis examines the medial construction of the Portuguese of Brazil (PB). It is a construction which describes a causative event in which a non-human subject participant is affected by an action that does not originate from itself. Thus, we are interested in investigating this type of construction, its specific characteristics, motivations and discursive context from its semantic- cognitive and discoursive - pragmatic functions. The research questions are: what is the prototypical structural configuration of the medial construction (MC) in the Portuguese of Brazil? What are its specific discoursive functions? What is the degree of MC transitivity based on the properties proposed by Hopper and Thompson (1980)? We assume that the medial construction has its own structure which particularizes its significant dimension, thus ensuring a certain distance between the one in charge of the event and the affected entity. The theoretical and methodological assumptions is founded on Usage-based Functional Linguistics (FURTADO DA CUNHA; BISPO; SILVA, 2013). It is a research of qualitative- interpretative nature that has prioritized the analysis of occurrences arising from texts produced by users of the Brazilian Portuguese language in effective communicative situation. The database for this study is electronic texts available on the website www.reclameaqui.com.br. The results revealed the existence of different configurations of the medial construction in the Brazilian Portuguese, having as prototypical the one formed by SN + V. From the morphosyntactic and semantic point of view, the construction expresses a subject affected by an action that does not part from itself. As for the pragmatic aspect, the construction expresses an event that seems to have the purpose to emphasize the affected argument and to ignore, intentionally or not, the agent or the causative, since it is irrelevant to the speaker/ listener in the contextual situation.
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The constant necessity for new sources of renewable energy is increasingly promoting the increase of investments in this area. Among other sources, the wind power has been becoming prominent. It is important to promote the search for the improvement of the technologies involved in the topologies of the wind turbines, seeking for alternatives which enhance the gotten performance, despite the irregularity of the wind speed. This study presents a new system for speed control, in this case applied to the wind turbines - the Electromagnetic Frequency Regulator (EFR). One of the most used devices in some topologies is the mechanical gearboxes which, along with a short service life, often represent sources of noise and defects. The EFR does not need these transmission boxes, representing a technological advancement, using for that an adapted induction machine, in which the stator becomes mobile, supportive to the axis of the turbine. In the topology used in this study, the EFR also allows us to leave out the usage of the eletronic converters to establish the coupling between the generator and the electrical grid. It also the reason why it provides the possibility of obtaining the generation in alternating current, with constant voltage and frequency, where there is no electrical grid. Responsable for the mechanical speed control of the generator, the EFR can be useful in other transmission systems in which the mechanical speed control output is the objective. In addition, the EFR operates through the combination of two inputs, a mechanical and other electrical. It multiplies the possibilities of application because it is able to synergistic coupling between different arrays of energy, and, for such reasons, it enables the various sources of energy involved to be uncoupled from the network, being the synchronous generator responsible for the system connection with the electrical grid, simplifying the control strategies on the power injected in it. Experimental and simulation results are presented through this study, about a wind turbine, validating the proposal related to the efficience in the speed control of the system for different wind conditions.
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Electrical disturbances such as voltage sags, interruptions and voltage unbalances might cause serious problems for the end-user and for the companies of generation and transmission of energy. Few years ago, those companies have been using methods and equipments of protection to avoid the disturbances’ presence or to mitigate their effects on the power system. Disturbances generators are used to analyse the behavior of electrical and electronic equipments affected by disturbances. The analysis of those failures allows the development of appropriated protection equipments. In this paper, the development of a disturbances generator based on power converters is presented. The disturbance generator developed is able to generate some symmetrical disturbances, such as: voltage sags, voltage swells and harmonic distortion. The control strategy used in the disturbance generator is based on discrete and repetitive control. The steps of the design of the control and of the filter used for reducing harmonic in the output, are detailed in the text. Are presented the obtained results on computational simulations and the obtained results on laboratory tests.
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The unbridled consumption of electronic equipment associated with fast immersion of new technologies on the market leads to the accelerated growth of electronic waste. Such waste mostly contains printed circuit boards in its structure. Printed circuit boards have many metals, including heavy metals, being highly toxic. Electronic waste is discarded improperly and indiscriminately, usually without any previous treatment and with other municipal waste, contaminating the environment and causing serious problems to human health. Beyond these metals, there are also precious metals and high value-added basis, that can be recovered and recycled, reducing the exploration of natural resources. Thus, due to the high growth potential and reuse of these waste treatment processes, characterization and separation were applied to the printed circuit boards. The printed circuit boards were subjected to physical treatments such as dismantling, crushing, sizing separation, magnetic separation and chemical treatments such as pyrolysis and leaching. Through characterization process (pyrolysis and leaching) the proportions of the components of the granulometric range were determined: 46,08% of metals; 23,32% of polymers and 30,60% of ceramics. It was also observed by particle size separation that metal components tend to concentrate in coarse fractions, while polymeric and ceramic components in fine fractions. From the magnetic separation process was obtained 12,08% of magnetic material and 82,33% of non-magnetic material.
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The electronic journals correspond publishing channels and dissemination of scientific information. Through them, users can spread their studies as well as developing new researches. One of the systems used for creation and e-journals management is the Electronic System for Journal Publishing (SEER), used in the construction of periodic portals, as well as the creation of magazines in isolation. In this purport, it is believed that the management systems and creation of e-journals should be developed (internally and externally) according to the needs of its users. In the case of internal development, some of these processes refer to the copyright registration and submission of articles, which, in turn, are relevant tasks in the editorial process. Thus, the proposed study, thematic Usability of scientific journals, aims to analyze the usability of the copyright registration process and submission of articles in the Electronic System for Journal Publishing through BiblioCanto magazine, part of the Electronic Journals Portal of the Federal University of Rio Grande do Norte (UFRN). For the realization of the research, two valuation techniques were used: the Usability Test with a total of twenty participants and the Cooperative Evaluation, with the same number of participants separated in four categories considered target audience of that magazine, namely: undergraduate students, graduate students, teachers and librarians. The results indicated that the two analyzed processes (copyright registration and submission of articles) need improvement. In the case of the registration process, the following needs are: signalizing of the conducting registration ambient; description and exclusion of requested information on the registration form. In the process of article submission, it is emphasized improvement of aspects: the early steps to submission, signaling of required fields, concise description of the steps, minimization and review of the steps. To this end, it is believed that in general idea the SEER partially meets the needs of its users regarding the usability of such software.
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The electronic journals correspond publishing channels and dissemination of scientific information. Through them, users can spread their studies as well as developing new researches. One of the systems used for creation and e-journals management is the Electronic System for Journal Publishing (SEER), used in the construction of periodic portals, as well as the creation of magazines in isolation. In this purport, it is believed that the management systems and creation of e-journals should be developed (internally and externally) according to the needs of its users. In the case of internal development, some of these processes refer to the copyright registration and submission of articles, which, in turn, are relevant tasks in the editorial process. Thus, the proposed study, thematic Usability of scientific journals, aims to analyze the usability of the copyright registration process and submission of articles in the Electronic System for Journal Publishing through BiblioCanto magazine, part of the Electronic Journals Portal of the Federal University of Rio Grande do Norte (UFRN). For the realization of the research, two valuation techniques were used: the Usability Test with a total of twenty participants and the Cooperative Evaluation, with the same number of participants separated in four categories considered target audience of that magazine, namely: undergraduate students, graduate students, teachers and librarians. The results indicated that the two analyzed processes (copyright registration and submission of articles) need improvement. In the case of the registration process, the following needs are: signalizing of the conducting registration ambient; description and exclusion of requested information on the registration form. In the process of article submission, it is emphasized improvement of aspects: the early steps to submission, signaling of required fields, concise description of the steps, minimization and review of the steps. To this end, it is believed that in general idea the SEER partially meets the needs of its users regarding the usability of such software.
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The Brazilian CAPES Journal Portal aims to provide Information in Science and Technology (IST) for academic users. Thus, it is considered a relevant instrument for post-graduation dynamics and the country´s Science and Technology (S&T) development. Despite its importance, there are still few studies that focus on the policy analysis and efficiency of these resources. This research aims to fill in this gap once it proposes an analysis of the use of the CAPES Journal Portal done on behalf of the master´s and doctoral alumni of the Post Graduate Program in Management (PPGA) at the Federal University of Rio Grande do Norte (UFRN). The operationalization of the research´s main objective was possible through the specific objectives: characterize graduate profile as CAPES Journal Portal users b) identify motivation for the use of CAPES Journal Portal c) detect graduate satisfaction degree in information seeking done at CAPES Journal Portal d) verify graduate satisfaction regarding the use of the CAPES Journal Portal e) verify the use of the information that is obtained by graduates in the development of their academic activities. The research is of descriptive nature employing a mixed methodological strategy in which quantitative approach predominates. Data collection was done through a web survey questionnaire. Quantitative data analysis was made possible through the use of a statistical method. As for qualitative analysis, there was use of the Brenda Dervin´s sense-making approach as well as content analysis in open ended questions. The research samples were composed by 90 graduate students who had defended their dissertation/thesis in the PPGA program at UFRN in the time span of 2010-2013. This represented by 88% of this population. As for user profile, the analysis has made evident that there are no quantitative differences related to gender. There is predominance of male graduates that were aged 26 to 30 years old. As for female graduates, the great majority were 31 o 35 years old. Most graduates had Master´s degree scholarship in order to support their study. It was also seen that the great majority claim to use the Portal during their post graduation studies. The main reasons responsible for non use was: preference for the use of other data bases and lack of knowledge regarding the Portal. It was observed that the most used information resources were theses and dissertations. Data also indicate preference for complete text. Those who have used the Portal also claimed to have used other electronic information fonts in order to fulfill their information needs. The information fonts that were researched outside in the Portal were monographs, dissertations and thesis. Scielo was the most used information font. Results reveal that access and use of the Portal has been done in a regular manner during post graduation studies. But on the other hand, graduates also make use of other electronic information fonts in order to meet their information needs. The study also confirmed the important mission performed by the Portal regarding Brazilian scientific communication production. This was seen even though users have reported the need for improvement in some aspects such as: periodic training in order to promote, encourage and teach more effective use of the portal; investment aiming the expansion of Social Sciences Collection in the Portal as well as the need to implement continuous evaluation process related to user satisfaction in regarding the services provided.