Implementação da rotina de unfolding para determinação de distribuição de tamanho de grãos esféricos via distribuição de interceptos lineares e de área de seção

Na unfolding method of linear intercept distributions and secction área distribution was implemented for structures with spherical grains. Although the unfolding routine depends on the grain shape, structures with spheroidal grains can also be treated by this routine. Grains of non-spheroidal shape can be treated only as approximation. A software was developed with two parts. The first part calculates the probability matrix. The second part uses this matrix and minimizes the chi-square. The results are presented with any number of size classes as required. The probability matrix was determined by means of the linear intercept and section area distributions created by computer simulation. Using curve fittings the probability matrix for spheres of any sizes could be determined. Two kinds of tests were carried out to prove the efficiency of the Technique. The theoretical tests represent ideal cases. The software was able to exactly find the proposed grain size distribution. In the second test, a structure was simulated in computer and images of its slices were used to produce the corresponding linear intercept the section area distributions. These distributions were then unfolded. This test simulates better reality. The results show deviations from the real size distribution. This deviations are caused by statistic fluctuation. The unfolding of the linear intercept distribution works perfectly, but the unfolding of section area distribution does not work due to a failure in the chi-square minimization. The minimization method uses a matrix inversion routine. The matrix generated by this procedure cannot be inverted. Other minimization method must be used

Estudo comparativo da utilização do nitrogênio como fluido alternativo após a injeção de vapor

Currently, due to part of world is focalized to petroleum, many researches with this theme have been advanced to make possible the production into reservoirs which were classified as unviable. Because of geological and operational challenges presented to oil recovery, more and more efficient methods which are economically successful have been searched. In this background, steam flood is in evidence mainly when it is combined with other procedures to purpose low costs and high recovery factors. This work utilized nitrogen as an alternative fluid after steam flood to adjust the best combination of alternation between these fluids in terms of time and rate injection. To describe the simplified economic profile, many analysis based on liquid cumulative production were performed. The completion interval and injection fluid rates were fixed and the oil viscosity was ranged at 300 cP, 1.000 cP and 3.000 cP. The results defined, for each viscosity, one specific model indicating the best period to stop the introduction of steam and insertion of nitrogen, when the first injected fluid reached its economic limit. Simulations in physics model defined from one-eighth nine-spot inverted were realized using the commercial simulator Steam, Thermal and Advanced Processes Reservoir Simulator STARS of Computer Modelling Group CMG

Avaliação da biodegradabilidade de petróleo utilizando microrganismos isolados do estuário do Rio Potengi (RN)

The oil activity in the Rio Grande do Norte State (RN) is a permanent threat to coastal ecosystems, particularly mangroves, with the possibility of oil spills. In this context, the objective of this study was to evaluate the potential resistance of the mangrove environment of a possible spill. Were selected and isolated microorganisms degrading oil by the technique of enrichment cultures and formation of a bacterial consortium. The kinetic study of the consortium was held in rotary incubator shaken at 150 rpm and 30° C. Samples were taken at intervals of 4 hours for analysis of cell concentration and surface tension. The biodegradation was monitored using two methods of respirometry: manometric (OxiTop-C ®) and conductivimetry, where the biodegradation of oil was estimated indirectly by oxygen consumption and CO2 production, respectively. Furthermore, it was used a full 2² factorial design with triplicate at central point to the runs that used the conductivimetric methodology.. The technique of enrichment cultures allowed to obtain thirteen bacterial strains. Kinetic study of the consortium, we can showed the absence of the lag phase, reaching a maximum cell concentration of 2.55 g / L at 16 h of cultivation and a reduction on surface tension. When we adopted the methodology of OxiTop-C was detected a band indicating biodegradability (1% oil v/v), however when we used the conductivimetry methodology did not observe any band that would indicate effective biodegradation. By monitoring a process of biodegradation is necessary to observe the methodology will be adopted to evaluate the biodegradation process, since for the same conditions adopted different methodologies can produce different results. The oil-degrading isolates from soils of the mangrove estuary Potengi / RN are largely to be used in bioremediation strategies of these places, in the case of a possible oil spill, or it can be used in the treatment of waste oil generated in saline environments, since they are optimized the conditions of the tests so that the efficiency of biodegradation reach the minimum level suggested by the standarts

Construção e controle inteligente de um manipulador robótico com dois graus de liberdade

The present work shows the development and construction of a robot manipulator with two rotary joints and two degrees of freedom, driven by three-phase induction motors. The positions of the arm and base are made, for comparison, by a fuzzy controller and a PID controller implemented in LabVIEW® programming environment. The robot manipulator moves in an area equivalent to a quarter of a sphere. Experimental results have shown that the fuzzy controller has superior performance to PID controller when tracking single and multiple step trajectories, for the cases of load and no load

Automação de um sistema rotatório para secagem do rejeito de maracujá

The rotary dryer is one of the most used equipments in processing industries. Its automatic control mode of operation is important specially to keep the moisture content of the final product in the desired value. The classical control strategies, like PID (proportional integral derivative) control, are largely used in the industrial sector because of its robustness and because they are easy to be implemented. In this work, a data acquisition system was implemented for monitoring the most relevant process variables, like: both inlet and outlet drying air temperature, dryer rotation, outlet air speed and humidity, and mass of the final product. Openloop tests were realized to identify a mathematical model able to represent the drying process for the rotary system. From this model, a PID controller was tuned using a direct synthesis method, assuming a first order trajectory. The PID controller was implemented in the system in order to control the inlet drying air temperature. By the end, closedloop tests (operating in automatic mode) were realized to observe the controller performance, and, after setting the best tune, experiments were realized using passion fruit seeds as raw material. The experiments realized in closedloop showed a satisfactory performance by the implemented control strategy for the drying air temperature of the rotary system

Avaliação de dois clones de Escherichia coli recombinante quanto ao crescimento e expressão de antígenos de Leishmania chagasi (kmp11 e P36)

Visceral leishmaniosis caused by Leishmania chagasi, also known as calazar, presented, in the period from 1990 to 2005, tax of incidence in Brazil varying between 1 and 3 cases for 100 000 inhabitants. The Northeast region that up to the year of 2000 contributed with almost 90% of the registered cases is reducing his participation in the current decade, reaching 56% in 2005. Conventional leishmaniasis treatment is costly and it shows high toxicity, demanding more research for alternative treatments, with special interest in development of vaccines and diagnosis kits which include production of recombinant antigens by host cells. Escherichia coli has been the microorganism most studied and used as a host for recombinant protein production. Therefore, the aim of this work was to study the influence of induction on cellular growth and to verify the type of Leishmania chagasi antigens expression (intra or extracellular) during two recombinant E. coli clones (kmp11 and P36) cultivation in rotary incubator (shaker) using three different media (2xTY, TB, FASS+EL). For that, tests were carried out using conditions established in the literature for E. coli (37°C and 200 rpm) and media supplemented with antibiotics to guarantee that only competent cells grows. First, tests were carried out without induction in order to verify the two microorganisms kinetic behavior (growth and substrate consumption) in different media. Next, the induction was carried out through the addition of IPTG (1mM as final concentration), at the first hour of cultivation. It was observed that protein expression were intracellular for all clones and media tested, however the highest level of expression was clearly observed by the electrophoresis band density (intensity) for 2xTY medium and kmp11 protein. Although it contains the lowest substrate concentration, consequently, a reduced cellular concentration when compared to other media, it appeared that this medium and clone combination is the most indicated for recombinant protein production. Therefore, the objective of this work was achieved, since the interested proteins were produced. Consequently, this result motivates new studies for production optimization using different cultivation strategies

Concepção de um secador rotatório para secagem do cefalotórax do camarão

The present work has as objective the knowledge of the process of drying of the cephalothorax of shrimp to give support the industry to make possible the use of this byproduct. In this sense, the process conditions in this tray dryer and spouted bed were analyzed. With these results, it was projected and constructs a dryer with specific characteristics for the drying of the cephalothorax. The desorption isotherms were obtained by the dynamic method in the temperatures of 20, 35 and 50º C and in the interval of 10-90% of relative humidity. It was observed that the product in form of powder can be conserved with larger stability for lower relative humidity to 40%. The curves of drying of the dryer of fixed bed were adjusted for the models: single exponential, biparametric exponential and Page. The model biparametric exponential more adequately described all the drying conditions studied. The tests carry out in spouted bed showed high drying rate for the material in the paste form in beds active dynamicly-fluid, provely the necessity of a feeding in shorter intervals of time to increase the thermal efficiency of the process. The projected dryer, be considered the obtained results, it was a rotary dryer with inert bed, feed co-current, discharge in cyclone to take place the separation gas-solid, and feed carry out in intervals of 2 minutes. The optimization of the equipment projected it was accomplished used the complete factorial experimental design 24, this had as independent variables temperature velocity of the air, feed flow rate and encapsulated concentration (albumin), as variables answers the thermal efficiency, the moisture content of obtained powder, total time of test and the efficiency of production of powder in several points of processing. The results showed that the rotary dryer with inert bed can present, also, good results if applied industrially

O que controla o crescimento do Fitoplâncton em lagoas costeiras tropicais? um modelo para a lagoa de Extremoz (RN)

The phytoplankton growth is dependent of several abiotic (nutrients, temperature) and biotic (predation by zooplankton) variables. In this work, a mathematical model was developed in Stella software to understand the planktonic dynamics of Extremoz Lagoon (RN) and to simulate scenarios of different environmental conditions. Data were collected monthly at two points of the lagoon. The state variables are phytoplankton and zooplankton and forcing variables are nitrogen, phosphorus and temperature. The results show that: a) the model are well coupled, especially when some constants assume different values; b) simulated nutrient concentrations reduction decreases phytoplankton biomass, but the increase of nutrients does not stimulate the growth; c) changes in the temperature does not change the phytoplankton biomass; d) changes in zooplankton biomass affect directly and reduces the phytoplankton, indicating a topdown control mechanism; e) changes in the nutrient concentration modified the biomass of zooplankton suggesting a rapid flow of energy between nutrients, phytoplankton and zooplankton and a ecosystem likely arranged in an inverted pyramid (higher concentration of zooplankton than phytoplankton)

Reflexões e contribuições para o ensino de gravitação clássica no nível médio

The subject of Classic Gravitation is part of the actual curriculum for High School in Brazil, and it is taught in the first year of that education level. This master thesis presents a research regarding the subject Classic Gravitation in High School. This research was based in two complementary guidelines of research and action. The first guideline was the analysis of 21 didactic books of physics which are the more frequently used in High School, in the city of Natal/RN. The second guideline, worked after being verified the most common deficiencies presents in the didactic books, was the elaboration, followed by a practical application, of a course suggesting how to approach that subject in the classroom. The Parâmetros Curriculares Nacionais para o Ensino Médio (National Curricular Parameters for High School PCNEM) defend that Classic Gravitation is very important in the student s formation and that its study helps the comprehension of many nature s phenomena. Because of this vision of that subject by the PCNEM, the 21 analyzed books were separated in two groups: the first one, containing 10 books, was edited before the spreading of PCNEM, and the second, with 11 books, after that spreading. Whatever the group to which the didactic books belonged, the great majority of them let that subject in a second plan; two of them even suggesting, in the teacher s orientations, that the subject Gravitation can be suppressed in case of insufficient time . These analyses points that the PCNEM had produced no changes in the conception of the authors that wrote books regarding that subject. To analyze the didactic books, we elaborated a script which was used as an analysis tool, in which we put in evidence the relative importance of the historic and philosophic contextualization of the subject, the quotidian experience of the students and the interdisciplinary approach, among other aspects. It became evident that the didactic books give very little emphasis to historic aspects of the knowledge construction, to the relations with the day-by-day questions and to the interdisciplinary character of the subject Gravitation. It calls attention the non concordance among the authors opinions regarding the necessary previous knowledge or prerequisites the students should fulfill in order to begin to study Gravitation. The course we elaborated was given to a group of teachers as well as to students. In those courses we treated theoretical and practical aspects and emphasized historical questions and the ones which are related to people s daily life. The course for teachers was realized as an extra-mural activity of the UFRN and was given by the author of this thesis at the Escola Estadual Francisco Ivo Cavalcanti (a state public school in Natal/RN). There were 23 teachers present, from several public schools and several fields of knowledge. The thesis supervisor and the master degree s colleagues of the author acted as collaborators , reporting the participants opinions and speeches. The course to the students, on the other hand, had the participation of 300 regular students who belonged to 6 different 1st year classes of the High School Escola Marista de Natal (RN), in which the author acts as a physics teacher. The student s course was realized as part of the regular curriculum activities, in which three classes stood under the responsibility of the author and other three classes in charge of another Marista s teacher, who participated as a collaborator . The teacher s course as well as the students one were given in two stages, with five hours each. The first stage was divided in two moments, the first one focused on the survey of the spontaneous conceptions about gravitation, in which we worked basically with experiments of free throwing and pendulum, and the second one focused in theoretical presentations and quarrels about universe s models. In the second stage of the course we improved the study of Kepler s laws and the Newton s Universal Gravitation law, and we used as motivating tools some practices involving the construction of the solar system in scale. As instruments for evaluating both courses we used questionnaires and reported the speeches with participants opinions, beyond usual written evaluations in the course for the students. The teachers who participated in the course showed very good wills in realizing interdisciplinary practices; nevertheless, according their own speeches, they frequently came across the difficulty of how to do . From the experience we had in both courses, we conclude that the approach we propose hear to the teaching of the subject Classic Gravitation , supported on the tripod theory, practice and historical and philosophical aspects, is viable and effective. One hopes that this research may contribute in the formation of a opinion, among the teachers, concerning how to approach the subject of Classic Gravitation, and may offer suggestions in order those who want to apply that approach may develop classroom practices aiming to improve the teaching of that subject, which has a singular importance in the formation of High School students

Vaga-lume na treva: a poesia de João Lins Caldas

This thesis analyses the poetry of João Lins Caldas (1888-1967), in Brazilian literature context, aiming at describing and understanding the main features of his poetry. Thus, this research presents a corpus to be worked on: the poems in Poeira do céu e outros poemas (2009). Our study is characterized by a biographical, historiographical and critical tendency, by trying to organize the manuscripts of the author and biographical aspects while analyzing his poems. It is showed the relation between Brazilian poetry written by some authors, since the parnasianism and symbolism period until the twentieth century. On the one hand, our analysis is based on the ideas and criticism by Antonio Candido (2006; 2002; 1985), discussing the process of formation of Brazilian literature and the procedure to analyse poetry. It is also based on the concept of poetry and resistance, developed by Alfredo Bosi (2000; 2002), and the notion of Brazilian matter, identified by Roberto Schwarz (1987, 1997, 1999). On the other hand, this work focuses on melancholy under the theoretical ideas of authors such as Aristotle (1998), Walter Benjamin (1984), Jaime Ginzburg (1997) and Moacyr Scliar (2003). This focus on melancholy contributes to a better understanding of one of the main themes found in the poems analysed. By studying the poetry of João Lins Caldas, it was perceived the relevance of melancholy and resistance in his verses. This can be seen in his dissonant language, characterized by the broken syntax in his verses, as well as contradictory images and complex meanings in his poetry. This causes the effect of unfamiliarity on the reader. His poetry is the result of a style that finds its place in the best moment of modern Brazilian poetry and reveals its singularity through the inverted syntax with powerful themes such as love, death, pain, delusion, loss, memory, nature and God. All of them are aspects of Brazilian historicity. Finally, the work of João Lins Caldas is part of a multifaceted poetry

Investigação da relação entre conteúdo onírico e aprendizado de uma tarefa cognitiva complexa

Several lines of evidence indicate that sleep is beneficial for learning, but there is no experimental evidence yet that the content of dreams is adaptive, i.e., that dreams help the dreamer to cope with challenges of the following day. Our aim here is to investigate the role of dreams in the acquisition of a complex cognitive task. We investigated electroencephalographic recordings and dream reports of adult subjects exposed to a computer game comprising perceptual, motor, spatial, emotional and higher-level cognitive aspects (Doom). Subjects slept two nights in the sleep laboratory, a completely dark room with a comfortable bed and controlled temperature. Electroencephalographic recordings with 28 channels were continuously performed throughout the experiment to identify episodes of rapid-eye-movement (REM) sleep. Behaviors were continuously recorded in audio and video with an infrared camera. Dream reports were collected upon forced awakening from late REM sleep, and again in the morning after spontaneous awakening. On day 1, subjects were habituated to the sleep laboratory, no computer game was played, and negative controls for gamerelated dream reports were collected. On day 2, subjects played the computer game before and after sleep. Each game session lasted for an hour, and sleep for 7-9 hours. 9 different measures of performance indicated significant improve overnight. 81% of the subjects experienced intrusion of elements of the game into their dreams, including potentially adaptative strategies (insights). There was a linear correlation between performance and dream intrusion as well as for game improval and quantity of reported dreaming. In the electrophysiological analysis we mapped the subjects brain activities in different stages (SWS 1, REM 1, SWS 2, REM 2, Game 1 and Game 2), and found a modest reverberation in motor areas related to the joystick control during the sleep. When separated by gender, we found a significant difference on female subjects in the channels that indicate motor learning. Analysis of dream reports showed that the amount of gamerelated elements in dreams correlated with performance gains according to an inverted-U function analogous to the Yerkes-Dodson law that governs the relationship between arousal and learning. The results indicate that dreaming is an adaptive behavior

Estudo comparativo de abordagens de inversão do fator de qualidade Q

Seismic wave dispersion and attenuation studies have become an important tool for lithology and fluid discrimination in hydrocarbon reservoirs. The processes associated to attenuation are complex and are encapsulated in a single quantitative description called quality factor (Q). The present dissertation has the objective of comparing different approaches of Q determination and is divided in two parts. Firstly, we made performance and robustness tests of three different approaches for Q determination in the frequency domain. They are: peak shift, centroid shift and spectral ratio. All these tests were performed in a three-layered model. In the suite of tests performed here, we varied the thickness, Q and inclination of the layers for propagation pulses with central frequency of 30, 40 and 60 Hz. We found that the centroid shift method is produces robust results for the entire suíte of tests. Secondly, we inverted for Q values using the peak and centroid shift methods using an sequential grid search algorithm. In this case, centroid shift method also produced more robust results than the peak shift method, despite being of slower convergence