21 resultados para Integrais
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
A necessidade de uma precisão e de uma aproximação dos resultados numéricos zeram com que diversas teorias surgissem: dentre elas, destacamos a Matemática Intervalar. A Matemática Intervalar surgiu na década de 60 com os trabalhos de pesquisa de Moore (MOORE, 1959) , em que ele propôs trabalhar com uma Matemática baseada na noção de intervalo real e não mais com um número como aproximação. Com isso, surgiu a necessidade de revisitar e reformular os conceitos e resultados da Matemática Clássica utilizando como base a noção de intervalo de Moore. Uma das áreas da Matem ática Clássica que tem tido muitas aplicações em engenharias e ciências é a Análises Numérica, onde um dos seus pilares é o Cálculo Integral e em particular as integrais de linha. Assim, é muito desejável se ter um cálculo integral dentro da própria Matemática Intervalar. No presente trabalho apresenta-se uma noção de Integral de Linha Intervalar baseada na extensão de integração proposta por Bedregal em (BEDREGAL; BEDREGAL, 2010). Para a fundamentação apresenta-se incialmente uma introdução sobre a pespectiva em que o trabalho foi realizado, considerando alguns aspectos histórico-evolutivos da Matemática Clássica. Os conceitos de Integrais de Linha Clássica, bem como algumas das suas aplicações mais importantes. Alguns conceitos de Matemática Intervalar necessários para o entendimento do trabalho. Para nalizar propomos uma aplicação da integral de linha em um experimênto clássico da mecânica quântica (a difração de um elétron em uma fenda) que graças ao fato de ser a Matemática Intervalar utilizada, nos dá um foco mais detalhado e mais próximo da realidade
Resumo:
COSTA, Roberta Kaliny de Souza ; ENDERS, Bertha Cruz ; MENEZES, Rejane Maria Paiva de . Trabalho em equipe em saúde: uma análise contextual. Ciência, Cuidado e Saúde, v. 7, p. 530-536, 2008.
Resumo:
In this work, ceramic powders belonging to the system Nd2-xSrxNiO4 (x = 0, 0.4, 0.8, 1.2 and 1.6) were synthesized for their use as catalysts to syngas production partial. It was used a synthesis route, relatively new, which makes use of gelatin as organic precursor. The powders were analyzed at several temperatures in order to obtain the perovskite phase and characterized by several techniques such as thermal analysis, X-rays diffraction, Rietveld refinement method, specific surface area, scanning electron microscopy, energy dispersive spectroscopy of X-rays and temperature programmed reduction. The results obtained using these techniques confirmed the feasibility of the synthesis method employed to obtain nanosized particles. The powders were tested in differential catalytic conditions for dry reforming of methane (DRM) and partial oxidation of methane (POM), then, some systems were chosen for catalytic integrals test for (POM) indicating that the system Nd2-xSrxNiO4 for x = 0, 0.4 and 1.2 calcined at 900 °C exhibit catalytic activity on the investigated experimental conditions in this work without showing signs of deactivation
Resumo:
The use of biofuels remotes to the eighteenth century, when Rudolf Diesel made the first trials using peanut oil as fuel in a compression ignition engine. Based on these trials, there was the need for some chemical change to vegetable oil. Among these chemical transformations, we can mention the cracking and transesterification. This work aims at conducting a study using the thermocatalytic and thermal cracking of sunflower oil, using the Al-MCM-41 catalyst. The material type mesoporous Al-MCM-41 was synthesized and characterized by Hydrothermical methods of X-ray diffraction, scanning electron microscopy, nitrogen adsorption, absorption spectroscopy in the infrared and thermal gravimetric analysis (TG / DTG).The study was conducted on the thermogravimetric behavior of sunflower oil on the mesoporous catalyst cited. Activation energy, conversion, and oil degradation as a function of temperature were estimated based on the integral curves of thermogravimetric analysis and the kinetic method of Vyazovkin. The mesoporous material Al-MCM-41 showed one-dimensional hexagonal formation. The study of the kinetic behavior of sunflower oil with the catalyst showed a lower activation energy against the activation energy of pure sunflower oil. Two liquid fractions of sunflower oil were obtained, both in thermal and thermocatalytic pyrolisis. The first fraction obtained was called bio-oil and the second fraction obtained was called acid fraction. The acid fraction collected, in thermal and thermocatalytic pyrolisis, showed very high level of acidity, which is why it was called acid fraction. The first fraction was collected bio-called because it presented results in the range similar to petroleum diesel
Resumo:
The present research carried out from three national dentistry magazines published in the period between 1990 and 2004, has as a goal to analyze how bioethics has been approached in this area, not only identifying the main concerns and tendencies, but also aiming to learn how this knowledge is produced and divulged in the dentistry circuit. We have articulated a quantitative-qualitative approach, studying 2995 articles. The articles were selected and assorted in twenty thematic categories, through their titles and key words. The analysis of the empiric material shows that, although there is a growth tendency of this discussion, little has been published about this theme (1,9%). Besides, it seems that there is an arrhythmia between the present bioethic approach in dentistry and the present life demands, where the deontology and legalist focuses are predominant, seeming to correspond to the inner aspects of the profession alone. In spite of this, through the qualitative approach it was possible to identify ways to build a more complex and integral odontological formation and practice. Within the conclusions, we still point out, that, this investigation, even face to its limitations, seems to offer subsidies for reflection and further studies about the theme, working as a parameter to keep up with the evolution of the bioethic thinking in the Odontology
Resumo:
Demand for access to higher education to put in test the education Brazilian system in view of the surplus of selective processes of public universities, people without option to pay their studies at this education level. In this context, it has arisen the University for All(Universidade para Todos)Program, the ProUni, from Ministry of Education - MEC, created by the Federal Government in 2004, and that it aims the granting of full and partial scholarships in private higher education institutions, graduate courses in sequential specific training, low-income Brazilians students who do not have higher-level degree. Created by the Provisional Measure No 213/2004 and institutionalized by Law No. 11096 of January 13, 2005, the ProUni offers, however, the exemption of some taxes to those institutions that join the program. This is one of the privileged time for the study of Social Representations by offering the researcher, a living laboratory, natural environment, the confrontation between the established and new. In time like this people are challenged to incorporate the new system to the pre-existing one, aiming it through a strangeness of what was so familiar. It is through this game of social forces that we developed the present study with 196 entering higher education, of these are 116 of selective vestibular system and 80 of the ProUni selective system. We opt by the procedures for data collection in order to have access to the circulating senses, in addition to the streamlined responses. With foundation in Abric, we perform the test the Free Association of Words, then analysed by the software and by EVOC Content of the type theme as Bardin. Besides, we require of the subjects, a writing on the study object university later analysed by the software ALCESTE. The results point out to a representation strongly rooted in social factors such as more traditional socio-cultural elements: the beliefs, values, the symbols. It is unique in both groups of subjects: among those entering by the selective ProUni system, there was a stronger anchor in that it does not make inquiries about the program. At the same time, there is a stronger presence of objectivation, entering the selective vestibular system in order that they explained with a value judgement on the programme. It is suggested further studies considering the embryonic state of social representation, as recent as the social purpose that triggered. It would be relevant even the replication of the same research with other people in order to strengthen the power of the theorising of empiria available
Resumo:
There are two main approaches for using in adaptive controllers. One is the so-called model reference adaptive control (MRAC), and the other is the so-called adaptive pole placement control (APPC). In MRAC, a reference model is chosen to generate the desired trajectory that the plant output has to follow, and it can require cancellation of the plant zeros. Due to its flexibility in choosing the controller design methodology (state feedback, compensator design, linear quadratic, etc.) and the adaptive law (least squares, gradient, etc.), the APPC is the most general type of adaptive control. Traditionally, it has been developed in an indirect approach and, as an advantage, it may be applied to non-minimum phase plants, because do not involve plant zero-pole cancellations. The integration to variable structure systems allows to aggregate fast transient and robustness to parametric uncertainties and disturbances, as well. In this work, a variable structure adaptive pole placement control (VS-APPC) is proposed. Therefore, new switching laws are proposed, instead of using the traditional integral adaptive laws. Additionally, simulation results for an unstable first order system and simulation and practical results for a three-phase induction motor are shown
Resumo:
Le présent ouvrage comprend des versions comparatives de neuf contes de Perrault, parmi les plus célèbres, publiés dans des éditions intégrales, au Brésil, entre 1934 et 2005. L analyse comparative donne la priorité à l identification des éléments relatifs à l oralité, comme ceux qui appartiennent, selon Ong (1998) et Havelock (1996), à des contextes de cultures antérieures à l épanouissement de l écriture et qui donc élaboraient ses propres structures de pensée et d expression pour interagir dans la vie pratique comme dans la création, dans la transmission et la manutention des coutumes et traditions. Issus des premiers récits, les contes de Perrault, traduits ou adaptés au Brésil, gardent en eux l esprit du langage narratif auquel l auteur français a consagré une attention spéciale, pour transposer dans l écrit quelques récits de la grande expérience humaine née dans le milieu populaire et qui désormais intègrent l espace de l écriture à chaque nouvelle version produite. Les bagages formulaires, comme les épithètes, les interventions du narrateur et la propre relation des signifations de l intrigue avec les structures de l imaginaire toujours présentes dans l humanité, démontrent le rapprochement entre l oralité et écriture. En suivant les discussions théoriques de Zumthor (1993, 1997, 2000) et par l interation du lecteur avec le texte, on constate que ces éléments relatifs à l oralité rendent possibl existence d une performance dans l écrit a partir des impressions cinesthésiques qui chaque lecture provoque chez le lecteur et récepteur d un texte narratif qui revendique, automatiquement, la construction d une ouvrage seulement possible à chaque instant de l interation, par le processus esthétique de la réception. Même au niveau d écrit, ou l intensité de sa présence est diminuée en raison de l absence d un corps physique qui transmet, qui développe, qui opere littéralement le texte par la voix et qui réunit l écoute et la vision de l auditeur, la performance produite s interpose entre le corps du lecteur qui agit sur le texte et en même temps reçoit les sensations lui permettant l expérience esthétique. Ainsi, dans l expérience de la lecture de Contes de Perrault est possible percevoir les éléments qui renvoient à la forme du conte de tradition populaire. Même déjà influencée par l écrit, le lecteur peut identifier, dans cette oeuvre, les possibilités determinantes de la dynamique perpétuel dans la transmission de ses textes: le plaisir de la pratique de l écoute des histoires contées oralement et le plaisir de la pratique de lectures silencieuses et solitaires. Dans ce chemin le lecteur devoit chercher les sens perdus, ici, rencontrés avec l aide des discours littéraires, linguistique, folklorique, anthropologique et psycanalytique sur la surface du texte narratif merveilleux. Outre cela, ces discours collaborent avec le lecteur qui retrouvent les voix emprisonnées par l écrit dans la virtualité et dans émergence d une performance
Resumo:
On this study we have revisited the predicted tidal circularization theory in close binary systems with a evolved component. Close binaries suffer tidal interactions that tend to synchronize periods and circularize the orbits (Zahn 1977, 1989, 1992). According to Zahn s theory we compute the integral that give us the variation of the eccentricity in a binary under the influence of tidal force and we compare the integral results with new observations for 260 binary systems with orbital solutions. Our results confirm the success of the Zahn s theory with a new data and new stellar evolutionary models, on the other hand, our results points to the need for a better description of the role of convection on this theory
Resumo:
Due to the fact of oral health sector reestructuration within Brazilian public health politics, this work had the object of evaluating, under users point of view, the accessibility to oral health services in Santa Cruz (RN), focusing on the organizational aspect. To achieve this, questionnaires were given to users in their homes, considering the censitary sector. Nine sectors of the urban zone were evaluated, selected by chance, and one from the rural zone, selected by convenience. The sample was composed by 194 users, calculated considering the estimated prevalence of event represented by the indicator I ve never been to the dentist + I ve been to the dentist more than three years ago from the Projeto SB Brasil Report . To complement the results, interviews were made with others actors involved in the process of oral health care: professionals (dentists) and manager (Health Municipal Secretary). From the data obtained it was possible to identify that 12,9% of the population had never visited the dentist, and that the search for the service was not influenced by the users individual and socioeconomics characteristics, excepting the gender. It was verified that 36,1% of the users went to the dentist in less than one year, with the youngests (p<0,05) being among those who went to the dentist more frequently. 63,3% of the interviewed related that they found some kind of difficulty when they search for dentistry services, with the difficulties for schedule, the queues and the long wait among the most cited. It was identified that 43,2% of the users wait three weeks or more for the appointment. It is still pointed out that 71,4% of the interviewed find difficulties to get urgency appointment, the long wait to be attended by the dentist was the most found. 92,9% and 94,1% of the interviewed had never been headed to especialized appointments and complementary exams, respectively. Due to the data founded, it was possible to verify that the accessibility to oral health services in Santa Cruz (RN) is damaged by factors related to the organization of public polices developed, mainly in relation to the working process
Resumo:
The present research aimed to analyze the presence of national scientific production in undergraduate studies in Psychology of Rio Grande do Norte. Therefore, the bibliographical references contained in education plan of subjects linked to the common center of the courses, which were taught in 2011 in three Psychology courses of the state, were focused. The analysis of the material was based on bibliographical and contextual aspects of the production, such as year, nationality, type of material, authorship (including the link of authors to PPGs), structuring axis of the subject in which it was mentioned, among others. The results showed that the national production is predominant in all courses, and they are, mostly, originated from PPGs of Psychology. Among these, the publications resulted from programs in Southwest, with emphasis to PUC-SP, are recent (mostly from 2000s) and they are predominantly composed by books (organizations and full texts). Regarding the distribution of Psychology PPGs production by the structuring axes, it is observed that it surpasses the foreign production only in axis C (procedures of scientific investigation and professional practice) and axis F (professional practices). Accordingly, it is concluded that Psychology production is found in graduation, sharing space with foreign publications and from other areas of knowledge. On the one hand, this is positive, by taking into account the importance of several foreign works and from other fields to build the knowledge in Psychology; on the other hand, it shows that the production from this area is inserted in graduation in a less significant way than its growth, which points out the existence of gaps in the development of some investigative domains from national Psychology
Resumo:
Microporous materials zeolite type Beta and mesoporous type MCM-41 and AlMCM-41 were synthesized hydrothermally and characterized by methods of X-ray diffraction, Fourier transform infrared, scanning electron microscopy, surface acidity, nitrogen adsorption, thermal analysis TG / DTG. Also we performed a kinetic study of sunflower oil on micro and mesoporous catalysts. The microporous material zeolite beta showed a lower crystallinity due to the existence of smaller crystals and a larger number of structural defects. As for the mesoporous materials MCM-41 and AlMCM-41 samples showed formation of hexagonal one-dimensional structure. The study of kinetic behavior of sunflower oil with zeolite beta catalysts, AlMCM-41 and MCM-41 showed a lower activation energy in front of the energy of pure sunflower oil, mainly zeolite beta. In the thermal cracking and thermocatalytic of sunflower oil were obtained two liquid fractions containing an aqueous phase and another organic - organic liquid fraction (FLO). The FLO first collected in both the thermal cracking as the thermocatalytic, showed very high level of acidity, performed characterizations of physicochemical properties of the second fraction in accordance with the specifications of the ANP. The second FLO thermocatalytic collected in cracking of sunflower oil presented results in the range of diesel oil, introducing himself as a promising alternative for use as biofuel liquid similar to diesel, either instead or mixed with it
Resumo:
Neste trabalho, um controlador adaptativo backstepping a estrutura variável (Variable Structure Adaptive Backstepping Controller, VS-ABC) é apresentado para plantas monovariáveis, lineares e invariantes no tempo com grau relativo unitário. Ao invés das tradicionais leis integrais para estimação dos parâmetros da planta, leis chaveadas são utilizadas com o objetivo de aumentar a robustez em relação a incertezas paramétricas e distúrbios externos, bem como melhorar o desempenho transitório do sistema. Adicionalmente, o projeto do novo controlador é mais intuitivo quando comparado ao controlador backstepping original, uma vez que os relés introduzidos apresentam amplitudes diretamente relacionadas com os parâmetros nominais da planta. Esta nova abordagem, com uso de estrutura variável, também reduz a complexidade das implementações práticas, motivando a utilização de componentes industriais, tais como, FPGAs (Field Programmable Gate Arrays ), MCUs (Microcontrollers) e DSPs (Digital Signal Processors). Simulações preliminares para um sistema instável de primeira e segunda ordem são apresentadas de modo a corroborar os estudos. Um dos exemplos de Rohrs é ainda abordado através de simulações, para os dois cenários adaptativos: o controlador backstepping adaptativo original e o VS-ABC
Resumo:
This research aims at developing a variable structure adaptive backstepping controller (VS-ABC) by using state observers for SISO (Single Input Single Output), linear and time invariant systems with relative degree one. Therefore, the lters were replaced by a Luenberger Adaptive Observer and the control algorithm uses switching laws. The presented simulations compare the controller performance, considering when the state variables are estimated by an observer, with the case that the variables are available for measurement. Even with numerous performance advantages, adaptive backstepping controllers still have very complex algorithms, especially when the system state variables are not measured, since the use of lters on the plant input and output is not something trivial. As an attempt to make the controller design more intuitive, an adaptive observer as an alternative to commonly used K lters can be used. Furthermore, since the states variables are considered known, the controller has a reduction on the dependence of the unknown plant parameters on the design. Also, switching laws could be used in the controller instead of the traditional integral adaptive laws because they improve the system transient performance and increase the robustness against external disturbances in the plant input
Resumo:
We use a tight-binding formulation to investigate the transmissivity and the currentvoltage (I_V) characteristics of sequences of double-strand DNA molecules. In order to reveal the relevance of the underlying correlations in the nucleotides distribution, we compare theresults for the genomic DNA sequence with those of arti_cial sequences (the long-range correlated Fibonacci and RudinShapiro one) and a random sequence, which is a kind of prototype of a short-range correlated system. The random sequence is presented here with the same _rst neighbors pair correlations of the human DNA sequence. We found that the long-range character of the correlations is important to the transmissivity spectra, although the I_V curves seem to be mostly inuenced by the short-range correlations. We also analyze in this work the electronic and thermal properties along an _-helix sequence obtained from an _3 peptide which has the uni-dimensional sequence (Leu-Glu-Thr- Leu-Ala-Lys-Ala)3. An ab initio quantum chemical calculation procedure is used to obtain the highest occupied molecular orbital (HOMO) as well as their charge transfer integrals, when the _-helix sequence forms two di_erent variants with (the so-called 5Q variant) and without (the 7Q variant) _brous assemblies that can be observed by transmission electron microscopy. The di_erence between the two structures is that the 5Q (7Q) structure have Ala ! Gln substitution at the 5th (7th) position, respectively. We estimate theoretically the density of states as well as the electronic transmission spectra for the peptides using a tight-binding Hamiltonian model together with the Dyson's equation. Besides, we solve the time dependent Schrodinger equation to compute the spread of an initially localized wave-packet. We also compute the localization length in the _nite _-helix segment and the quantum especi_c heat. Keeping in mind that _brous protein can be associated with diseases, the important di_erences observed in the present vi electronic transport studies encourage us to suggest this method as a molecular diagnostic tool