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A influência da preferência por brindes no autorrelato de desempenho em tarefas de leitura
(Universidade Federal de São Carlos, 2011-03-02)
Rabelo, Laura Zamot
;
Rose, Julio Cesar Coelho de
;
https://lattes.cnpq.br/3386857761295187
;
https://lattes.cnpq.br/8073723161368032
This study aimed at investigating the correspondence in a do-say activity. Two experiments were carried out: the first intended to clarify the effects of choice and preference for items on the self-report of children in a reading task performed on the computer; the second experiment endeavored to search for effects of previous reinforcement history using the same task as the former. Six children aged between 7 and 10 took part in Experiment 1. Doing consisted of reading a word out loud and saying comprised the report of having emitted a correct answer or having made a mistake. The entire task was performed on the computer. The item preference was determined by an interview done with the subjects themselves and it was also assessed by a multiple-stimuli without replacement test. The self-report of mistakes and correct answers for each subject was registered during three baseline sessions and no differential consequences followed any particular self-report. Afterwards, the subjects were exposed to the testing sessions with the objects evaluated as of high, medium and low preference, with and without the possibility of choosing what item they wanted to obtain. The total number of sessions was 18 and each of them was planned with 50% of words the subjects did not know how to read. The children were informed that they could only receive the treat (one of the preference items) if they had at least 15 points as the final score what would sum up to 75% or more of right answers for each session. Therefore, to every report of right answer, a point was added to the total score and it was presented on a screen shown in the intertrial interval. The percentage of noncorrespondent reports increased during the testing sessions, if compared to the baseline. It can be noticed a progressive raise on the non-correspondent reports of correct answers for all the subjects, nevertheless, the data were variable. The Experiment 2 aimed to broaden the results of the first and also to evaluate the role of historical variables represented here as a correspondence training carried out before the testing sessions. Three children between 7 and 10 years old were the subjects. The results obtained in the second experiment did not substantially differ from the first. Similar to Experiment 1, the data obtained from Experiment 2 for all children show an increase on emission of self-reports of correct answers, regardless if they made a mistake or not. There were not observable choice effects in both experiments. Moreover, the pattern of responses of most of subjects differed from what was to be expected if the reports were in function of preference. In conclusion, it is of fundamental importance to investigate the role of the score shown during the task as it may have functioned as an immediate conditioned reinforcer during the sessions increasing the emission of reports of correct answers. Keywords: verbal/nonverbal correspondence, reading, preference for consequences, reinforcement.
Dinâmica populacional de Euterpe edulis Martius em Floresta Ombrófila Densa no sul da Bahia
(Universidade Federal de São Carlos, 2011-03-02)
Mafei, Rodolpho Antunes
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Matos, Dalva Maria da Silva
;
https://lattes.cnpq.br/4728734263109138
;
https://lattes.cnpq.br/0804832742490928
Euterpe edulis is a very important palm tree from the Brazilian Atlantic Forest due to its ecological and economic role. However, due to the indiscriminate overexploitation its populations has been reducing greatly. This study aimed to characterize the conservation status of a E. edulis population in a fragment of Atlantic Forest at Southern Bahia. We monitored this population along 5 running years in a 0.8 hectare. Environmental variables were also collected to test which factors could affect plant development and projection matrices analysis were performed to estimate the population growth rate and sensibility. The results showed that population s density is lower if compared with others studies. We verified a decrease in the seedling s recruitment over years, which were attributed to fragmentation side-effects, such as microclimate changes and / or reproductive isolation or inbreeding depression. We also observed that the low rate of transition from stages 1 to 2, represents a bottleneck for the population growth. These results emphasize the urgency of more long-term studies on the population ecology and genetic of E. edulis and also management strategies to promote the sustainability of such natural populations.
A equação de Yang-Baxter para modelos de vértices com três estados
(Universidade Federal de São Carlos, 2011-03-02)
Pimenta, Rodrigo Alves
;
Martins, Márcio José
;
https://lattes.cnpq.br/1875815921495261
In this work we study the solutions of the Yang-Baxter equation associated to nineteen vertex models invariant by the parity-time symmetry from the perspective of algebraic geometry. We determine the form of the algebraic curves constraining the respective Boltzmann weights and found that they possess a universal structure. This allows us to classify the integrable manifolds in four different families reproducing three known models besides uncovering a novel nineteen vertex model in a unified way. The introduction of the spectral parameter on the weights is made via the parameterization of the fundamental algebraic curve which is a conic. The diagonalization of the transfer matrix of the new vertex model and its thermodynamic limit properties are discussed. We point out a connection between the form of the main curve and the nature of the excitations of the corresponding spin-1 chains.
Voto: uma oferta de fé. O poder simbólico dos líderes religiosos e o comportamento eleitoral dos membros da igreja evangélica
(Universidade Federal de São Carlos, 2011-03-02)
Souza, Julio Cesar Pereira de
;
Kerbauy, Maria Teresa Miceli
;
https://lattes.cnpq.br/4762029784021248
;
https://lattes.cnpq.br/7201126524337975
The way of making politics in the churches in Brazil has changed considerably due to the growth of evangelical denominations. The neopentecostal churches , emerged in the mid-70s, grew up quickly and now they are communities strongly disputed by the political leadership to represent an important portion of the national constituency. Considering the problem of charisma, the symbolic capital, i.e, the influence of the religious leader, we studied the voting behavior of campaigns for state and federal deputies in the International Church of God`s Grace (Igreja Internacional da Graça de Deus) from 1998 to 2006 addressing the transformation of its members in militants and faithful voters. Therefore, we analyze the guidelines of the speech delivered by the church leadership in the process of electoral persuasion, the media material, the logistics of the campaign and the participation of members in this process.
Efeito ansiolítico do ondansetron, antagonista dos receptores 5-HT3, injetado na amídala de camundongos submetidos à exposição e reexposição no labirinto em cruz elevado
(Universidade Federal de São Carlos, 2011-03-02)
Nunciato, Ana Claudia
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Souza, Azair Liane Matos do Canto de
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https://lattes.cnpq.br/2352004564367849
;
https://lattes.cnpq.br/4045394375772114
Against of stimuli that are dangerous, animals manifest defense reactions that cause fear and anxiety. These stimuli activate the serotonergic system, which sends projections to structures involved in defense mechanisms such as the septum, hypothalamus, hippocampus, amygdala and periaqueductal gray modulates the behavioral changes that can be characterized as anxiety. Studies have shown that 5-HT3 receptors are part of this modulation. The elevated plus maze (EPM) is a widely used animal model to evaluate the anxiolytic activity of drugs. Currently, it is known that the retest in rodents (rats and mice) increases the avoidance of it, this phenomenon, which refers to "a display of tolerance" (OTT, One Trial Tolerance). The amygdala is a prosencephalic structures that have significant amount of serotonin (5-HT) in this way, recent results from our laboratory have shown that microinjections of ondansetron antagonist 5-HT3 receptors in the amygdala of mice produced anxiolytic-like effect evaluated in LCE. The aim of this study was to evaluate the involvement of receptors 5-HT3 receptors in the amygdala of mice prior experience the elevated plus-maze (EPM). Conventional measures of anxiety (% of entry and time spent in open arms), locomotor activity (frequency in closed arms) and ethological measures related to risk assessment were recorded. The present study demonstrated that intra-amygdala of ondansetron, antagonist of 5-HT3 receptors, produced anxiolytic-like effects in naive mice and mice prior experience the LCE. The injection of ondansetron in only one of the exhibits produced anxiolytic-like effect, which leads us to conclude that the drug produced no change in memory. Both the Trial 1 and in Trial 2, none treatments affected locomotor activity. So while the amygdala is involved in the neurobiology of the defense reactions such as anxiety response, as it refers to the phenomenon it seems OTT not to participate.
Homotopias finitamente fixadas e pares de homotopias finitamente coincidentes
(Universidade Federal de São Carlos, 2011-03-02)
Cotrim, Fabiana Santos
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Vendrúscolo, Daniel
;
https://lattes.cnpq.br/8602232587914830
;
https://lattes.cnpq.br/5304106217466160
In the area of the theory of fixed points and coincidences of Nielsen, this study aims to develop techniques to minimize the set of fixed points in homotopies and the set of coincidences in pairs of homotopies. The techniques are based on Hopf construction for selfmaps of polyhedrons and on the results presented by Helga Schirmer in context of _x-finite homotopies. For pairs of homotopies, we created the concept of coincidences finite and we proved that certain pairs of homotopies can have their set of coincidences minimized in order to become coincidences finite.
Resiliência de sistemas alimentares: do local ao global
(Universidade Federal de São Carlos, 2011-03-02)
Ferreira, Marina Vianna
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Nordi, Nivaldo
;
https://lattes.cnpq.br/8168865557947289
;
https://lattes.cnpq.br/9020309796452848
Monitoramento em tempo real da orientação molecular de poliestireno e em misturas com polimetilmetacrilato durante a extrusão
(Universidade Federal de São Carlos, 2011-03-02)
Santos, Adillys Marcelo da Cunha
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Canevarolo Júnior, Sebastião Vicente
;
https://lattes.cnpq.br/4153664441338178
;
https://lattes.cnpq.br/4714910313876978
In this work it was studied the flow orientation of pure polystyrene and its diluted mixtures with polymethylmethacrylate as second phase during extrusion process by in-line monitoring of the polarized transmitted light intensity. The optical device is attached to the extruder exit by means of a slit-die possessing bores fitted with borosilicate transparent glass windows where light may go through to reach the flow. Upon pressurization, the windows internal structure changes which influences its optical response. The expected sine-square fitting relating transmitted light intensity and applied pressure on the windows is applied to the data. Doing that the software is able to deduct the glass windows strain birefringence from the polymer flow birefringence contribution. Stopping the feed allowed the in-line monitoring at a continuous decrease in shear rate replacing the time-consuming and waste of material of the steady-state. Amidst the samples evaluated, the higher viscosity polystyrene presented a high orientation level inducing an optical path difference above the half first order (OPD > 275nm). On shear rate decreasing the orientation of the flowing polymer reduces, displayed by the optical detector as a change in the transmitted light intensity, following a sinusoidal curve. Addition of a second phase to the PS matrix both lower the transmitted light intensity due to the turbidity created by the scattering particles presented in the medium and shifts the curves maxima to higher pressure values. The latter case is explained by the generation of methyl methacrylate monomer that diffuses into the PS matrix reducing its viscosity and so the chain orientation. Statements above revealed a vector called Azimuthal influence of the Concentration.
Síntese assistida por microondas de LiMn2O4, caracterização e testes como catodo para dispositivos de armazenamento de energia
(Universidade Federal de São Carlos, 2011-03-02)
Silva, João Pedro da
;
Biaggio, Sonia Regina
;
https://lattes.cnpq.br/0418215244233120
;
https://lattes.cnpq.br/2087603202355409
Lithium manganese oxide - LiMn2O4 - was produced by a microwaveassited solid state reaction. Solid mixtures containing LiOH.H2O and -MnO2 (synthesized electrolytically) underwent microwave irradiation for 3, 4 and 5 min. The obtained material was characterized by X-ray diffraction (XRD), scanning electron microscopy and cyclic voltammetry. Conductivity measurements and charge / discharge tests were carried out with the mixture: 85% LiMn2O4 / 10% carbon black / 5% PVDF. XRD analyses showed that LiMn2O4 was obtained in a single phase of cubic structure belonging to the space group Fd3m in only 3 min of microwave irradiation. This short time for the LiMn2O4 synthesis represents an energy saving greater than 90% when compared with the time employed in the traditional method of synthesis. SEM micrographs showed morphological changes and particle size increase when the microwave irradiation time was increased. The mixture (85% LiMn2O4 / 10% carbon black / 5% PVDF) presented electronic conductivity similar to that of a semiconductor (σ ~ 10-1 S m-1), which is adequate for using as cathode in lithium ion battery. Charge and discharge tests showed good electrochemical stability for all the oxides synthesized at different times, evidenced by a small decrease (12 to 17%) of their specific capacities during 30 cycles of charge and discharge. The oxide produced at 3 min of microwave irradiation presented the highest charge supply (77 93 mA h g-1) at an elevated discharge rate (C/1), besides a highly uniform morphology and the lowest particle size (~1 μm).
Megafauna do quaternário tardio dos depósitos cársticos do Alto Vale do Ribeira, sudeste do Estado de São Paulo, Brasil
(Universidade Federal de São Carlos, 2011-03-02)
Ghilardi, Aline Marcele
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Bichuette, Maria Elina
;
https://lattes.cnpq.br/8453043393798516
;
https://lattes.cnpq.br/5761534317977568
The carbonate caves of the Upper Ribeira Valley, southeastern São Paulo State, Brazil, preserve abundant fossil record of Pleistocene-Holocene South American megafauna. This work presents a historical review of its paleontological studies, as well as an update taxonomic survey of the megafauna material gathered since the beginning of the explorations in the area. Herein are also discussed paleobiogeographic and paleoecological questions and presented new Electron Spin Resonance dating results of the Ribeira s material. The fossil megafauna of the Upper Ribeira karstic region include: Eremotherium laurillardi, Nothrotherium maquinense, Lestodon armatus, Catonyx cuvieri, Ocnopus gracilis‟, Ahytherium aff. aureum, Glyptodon clavipes, G. reticulatus, Hoplophorus cf., Toxodon spp., Stegomastodon waringi, Tapirus terrestris,. Equidae indet., Smilodon populator and Panthera onca, of which only P. onca and T. terrestris still remain in the region. The register of Equidae here presented is the first for this area and also the first formal entry for the São Paulo state. The fossil assemblage recorded shows greater biogeographical affinity to the mega-mammal community of the intertropical region, though a typical taxon from pampean localities was also found. This denotes that the area should be a transition zone. The ecology of the species found suggests bygone occurrence of fairly different environmental settings than the existing one in the area. There were more temperate climates associated with open vegetation physiognomies, what agrees with the already known paleopalinological data. The fossil material does not show any kind of cronocorrelation given the type of genesis of the cave accumulations; and paleoecological investigations indicate that these fossils does not represent a real biocoenosis, but depict different faunistic moments related to climate oscillations during the Quaternary. The results obtained with the absolute dating corroborate the hypothesis that the Vale do Ribeira material belong to Late Pleistocene Holocene age; and also give the first biocronological insight for an extinct group in this area. To better understand the information provided by these deposits, further efforts on prospection and dating should be conducted, as well as detailed taphonomic investigations. The studies of the Quaternary fauna in São Paulo State come to fill an important gap in the intricate history of the South American megafauna.
Discriminações simples e reforçamento específico e diferencial para cada classe no ensino de leitura a indivíduos com atraso no desenvolvimento
(Universidade Federal de São Carlos, 2011-03-03)
Zaine, Isabela
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Domeniconi, Camila
;
https://lattes.cnpq.br/0665572503019533
Training procedures in researchs about the estabilishment of stimulus equivalence classes are tipically based on conditional discriminations, in wich a sample controls selection of a comparison stimulus. Proposals based on simple discrimination have been suggested in order to expand the potential of such technology and empirical model. Considering also that reinforcers are a part of stimulus equivalence class, the use of specific reinforcers to each class may assist in the emergence of equivalent stimuli classes. The preset study aimed to propose a training structure combining simple and conditional discrimination and differential and specific reinforcement for each stimulus class to teach reading of six simple isolated words from to individuals with developmental delay. Participants were 14 individuals with developmental delay enrolled in a special education institution with ages ranging from nine to 15 years. They were divided in two groups and randomly assigned to an experimental or control group. LECH-GEIC software was utilized for programming and effectuation of the teaching program, which training consisted on four phases: 1. simple discrimination between pictures 2. simple discrimination between printed words, 3. conditional discrimination between pictures with onomatopoeic auditory model. 4 conditional discrimination between printed words with onomatopoeic auditory model. Results pointed that there was a higher number of repetitions and errors in the conditional discriminations condition. There was evidence of formation of stimuli equivalence classes for all or some classes of stimuli for all participants in the experimental group. The average percentage of correct selections on symmetry and transitivity tests evaluated by BC and CB matching performances was substantially higher in post-test (CB = 81.3%, BC = 72%) compared to pre-test (CB = 45.8 % BC = 40.4%), and this difference was statistically significant (Wilcoxon Z =- 2.197, p <0.028 (BC) Z =- 2.366, p <0.018 (CB)). Reading of the training words for this group increased from a correct average percentage of 2.3% at pre-test to 53.57% at post-test (Wilcoxon Z =- 2.371, p <0.018). There were no statistical significant differences in performance between control and experimental groups at pre-tests (Mann-Whitney U), however, the experimental group, at post-tests, scored significantly higher in comparison to the control group at AC (U = 1 , 0, p <0.001), BC (U = 2.0, p <0.002), CB (U = 6, p <0.017), CC (U = 10.0, p <0.043), CRCCs (U = 8 , 0, p <0.038) relations and naming of training words (U = 0.5, p <0.001). Neither group presented generalized reading. By starting from a simple discrimination training prior to conditional discrimination, the procedure has created a situation of complexity teaching from simple to more elaborate repertories. The use of specific reinforcers may have assisted the emergence of untrained repertoires, such as AC, BC, CB relations and reading. The performance on equivalence tests and reading of some stimuli may have been hampered by multiple similarities between some written words and absence of auditory model in training phases, since onomatopoeic sounds were used as models in situations of conditional discriminations.
Secagem de resíduos cítricos em secador rotativo
(Universidade Federal de São Carlos, 2011-03-03)
Perazzini, Hugo
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Freire, José Teixeira
;
https://lattes.cnpq.br/2270677706718167
;
https://lattes.cnpq.br/2676311547535414
In this present work, an experimental study about simultaneous heat and mass transfer phenomena was carried out during the drying process of citric solid waste in a direct-heat contact semi-pilot rotary dryer, operating with continuous feed of solids. The drying experiments consisted of obtaining humidity and temperature data as function of time for the solid and gaseous phases, evaluating the influence of the operational variables of the process. The material characterization was studied in relation to the apparent and real specific masses, porosity, specific heat and hygroscopicity. The last one was determined by thermodynamic equilibrium conditions and by the thin-layer drying kinetics of the solid waste in a fixed bed dryer. In parallel, a two-phase mathematical model of lumped parameters was developed based on macroscopic balances of mass and energy for the solid and for the drying air. The differential algebraic system was solved numerically using a computer routine developed in MatLab®, where the drying process was simulated taking into consideration the particle residence time distribution inside the dryer. The comparison between the predicted and observed results showed that the model needs some improvement, but permits a preliminary qualitative analysis of the drying process.
Obtenção e caracterização de nanocompósitos de poli(cloreto de vinila): plastisol com argila
(Universidade Federal de São Carlos, 2011-03-03)
Bettio, Paola Pedroza Serpa de Biasi
;
Pessan, Luiz Antonio
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https://lattes.cnpq.br/8276650236213537
This project aims to study the effect of adding nanoparticles in the plastisol of poly(vinyl chloride) microsuspension. The influence of two different types of nanoclay, sodium montmorillonite and organophilic montmorillonite modified with quaternary ammonium salt was evaluated, considering both the method of exfoliation of the clay and the influence of concentration. The nanoclay at a concentration of 2.5, 5 or 10 phr, was previously exfoliated in plasticizer, under the action of shear and temperature in kaule mixer. Three plasticizers were used, Diisobutyl phthalate, Diisononyl phthalate and ester polyglycolic. Experiments without the prior exfoliating clay, were also performed for validation of its influence. The plastisol was obtained by mixing the nanoclay with PVC, diisononyl phthalate plasticizer and other additives in planetary mixer. The focus of the study will be not only to investigate the influence of nanoparticles on the improvement of rheological properties, but the influence on the mechanical properties, expanding the application of this resin. As the resin obtained will be attending the main application market, the analysis will focus on characterization for this particular application. Data analysis was performed with the aid of statistical method. It was possible to affirm that type of clay and also its concentration have influence on the viscosity. The prior exfoliation of the clay was not proved to be effective. It was possible to affirm that type and concentration also have significant influence on the opacity of the spread coating. In relation to thermal stability, it was possible to observe reduction in the nanocomposites containing organophilic modified nanoclay. In relation to the mechanical proprieties, it was possible to affirm that only the concentration of the clay was significant to the result, as its increase resulted in a decrease of these properties, with the exception of the Young modulus.
Distribuição vegetal ao longo dos gradientes ambientais de um estuário irregular
(Universidade Federal de São Carlos, 2011-03-03)
Ribeiro, José Pedro Nepomuceno
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Lima, Maria Inês Salgueiro
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https://lattes.cnpq.br/2171993314203162
;
https://lattes.cnpq.br/5713780053868735
Obtenção e caracterização elétrica de filmes finos de SnO2:Sb
(Universidade Federal de São Carlos, 2011-03-03)
Conti, Tiago de Goes
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Leite, Edson Roberto
;
https://lattes.cnpq.br/1025598529469393
;
https://lattes.cnpq.br/2091351741982251
The growing demand for advanced electronic devices based on nanomaterials has motivated efforts to produce nanoscale building blocks with designed functions. Transparent conducting oxide nanocrystals (TCONs) are particularly promising for the development of such devices. TCONs synthesized in an organic medium play an important role as building blocks because nonaqueous processes allow for greater control of the reaction pathways on a molecular level, enabling the synthesis of nanomaterials with high crystallinity and well-defined and uniform particle morphologies. This work describes the synthesis of highly conducting antimony-doped tin oxide (ATO) nanocrystals prepared via a nonaqueous sol-gel route in the size range of 4-7 nm, as well as insights into its electrical properties when processed as pellet and thin films. The antimony composition was varied from 1 to 18 mol% and the lowest resistivity (4.0x10-4 Ωcm) was observed at room temperature in the SnO2:8.8%molSb composition. The samples were evaluated by XRD, HRTEM, EDX, and SEM, resistivity measurements were taken in the four-probe mode in the temperature range of 77-300K and Hall-effect measurements were taken at room temperature. The preparation of crystalline ATO nanoparticles fully redispersible in organic solvents consists in one pot reaction under solvothermal treatment of tin (IV) chloride and antimony (III) chloride in benzyl alcohol at 150°C for 48h. The ATO nanocrystals were collected by centrifugation and washed twice with THF. The pellets were prepared by pressing 200mg of ATO nanoparticles under 4 MPa into a rigid die in a single axial direction through a rigid punch and the thin films produced via dip-coating deposition on quartz substrate. The results show highly crystalline nanoparticles in a monodisperse colloidal system, dependence on the shape of ATO nanoparticles as a function of Sb distribution and low resistivity.
Caracterização da resistência à corrosão de ligas inoxidáveis Fe-Mn-Si-Cr-Ni-(Co) com efeito de memória de forma
(Universidade Federal de São Carlos, 2011-03-03)
Rovere, Carlos Alberto Della
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Kuri, Sebastião Elias
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https://lattes.cnpq.br/6842072916153866
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https://lattes.cnpq.br/8141224513975606
In this work, the corrosion behavior of three Fe-Mn-Si-Cr-Ni (Co) shape memory stainless steels (SMSS) in aggressive environments was characterized. The electrochemical corrosion behavior in 0.5 M H2SO4 solution was obtained by potentiodynamic polarization, linear polarization, potential decay curves, electrochemical impedance spectroscopy (EIS), and Mott-Schottky analyses. Localized corrosion resistance was evaluated by potentiodynamic polarization measurements in 3.5% NaCl solution. The corrosion performance in highly oxidizing environments was evaluated based on immersion tests in boiling HNO3 solution. The passive film composition was analyzed by X-ray photoelectron spectroscopy (XPS). The test results were compared with that of a type 304 (SS 304) austenitic stainless steel. The three SMSSs exhibited a passive behavior in 0.5 M H2SO4 solution; however, their anodic behavior in the active dissolution region was markedly different. The passive current densities of the SMSSs were similar to that of SS 304, although the critical anodic current required for passivation was higher. The corrosion rate of the SMSSs in 0.5 M H2SO4 solution was much higher than that of SS 304. It was observed that the amount of Cr and Mn plays an important role in the corrosion behavior of SMSS. The XPS analyses indicated substantial Si content (in the chemical form of a silicate) in the anodic passive films formed on SMSS. Mott-Schottky analyses suggested that the Si acts as a dopant in the films, making them less defective and thicker than the films formed on SS 304. Due to their high manganese content, SMSSs are highly prone to pitting corrosion in chloride environments. SMSSs exhibit better corrosion resistance than SS 304 in highly oxidizing environments.
Estudo da alimentação de sólidos em sistemas de transporte pneumático
(Universidade Federal de São Carlos, 2011-03-03)
Lopes, Cibele Souza
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Freire, José Teixeira
;
https://lattes.cnpq.br/2270677706718167
;
https://lattes.cnpq.br/3627302739758354
One of the most important parts in a pneumatic conveying is the solids feeding system due its complexity fluid dynamic, besides affecting the operational stability, economical and technical feasibility and system efficiency. The purpose of this wok was to carry out a experimental study of fluid dynamic of feeding configuration for different operational conditions, made of non-mechanicals devices and reduction nozzle combinations, considering the influence in all pneumatic conveying system. The feeders applied were inclined pipe and L-valve, with and without reduction nozzle. Moreover, the spouted bed and the horizontal feeders were analyzed as well, which on their original design has reduction area for the flow. An analyses and a comparison of the fluid dynamic data obtained for feeding configurations in a pneumatic loop with 53,4 mm of internal diameter tube and transporting 1 mm glass spheres showed a relationship between the operational conditions and the type of feeder, resulting in air velocity and solid flow rate characteristics for each case . This study also gives the idea to apply reductions nozzles combined with non-mechanicals solid feeder in order to increase the solid flow rate. Up to the moment, the reduction nozzle was indicated just to get better the operation stability.
Deformação em canal angular de uma liga Al-4%Cu: efeito dos mecanismos de endurecimento na resistência mecânica e ductilidade
(Universidade Federal de São Carlos, 2011-03-03)
Prados, Erika Fernanda
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Sordi, Vitor Luiz
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https://lattes.cnpq.br/8364164402481940
;
Ferrante, Maurizio
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https://lattes.cnpq.br/6067173982945625
Internal boundaries hardening and precipitation hardening are two important mechanisms acting in metallic alloys. The former has special relevance when the grain size is reduced to dimensions below 1 μm, and this can be accomplished by a variety of Severe Plastic Deformation techniques, such as Equal Channel Angular Pressing. The objective of the present thesis is a better understanding of the strengthening mechanisms and work-hardening behavior of a precipitation hardening Al alloy subjected to Equal Channel Angular Pressing. The pertinent literature almost invariably shows that high strength goes together with low work hardening rate, that is, the stress-strain curve tends to be flat, meaning that highly deformed metals and alloys show low ductility. Among the strategies devised to counteract this effect, post deformation precipitation heat treatments seem to have a beneficial effect on the work hardening rate. In this condition precipitates would reduce the dynamic recovery rate and additionally promote some hardening. The present study was performed on an Al-4%Cu alloy, deformed by up to four passes of equal channel angular pressing and heat treated according to different schedules, including post deformation ageing. The work is divided in three sections: (i) Severe plastic deformation influence on precipitation; (ii) Correlation of strength and ductility with the Al2Cu precipitates dispersion, while the work hardening behavior is described by the relevant Kocks-Mecking curves; (ii) Study of the contribution of each of the four hardening mechanisms on final strength: work hardening, solid solution, precipitation and internal boundaries hardening. Conclusions show that a fine precipitate dispersion increases the work hardening rate by limiting dynamic recovery rate. It was also ascertained that cold deformation accelerates precipitation by a factor of three, however, precipitation hardening is swamped by the softening effect caused by the precipitation heat treatment itself.
Estudo da influência de argilitos e feldspatóides em composições de porcelanato
(Universidade Federal de São Carlos, 2011-03-03)
Hoffmann, Felipe Schlittler
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Morelli, Márcio Raymundo
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https://lattes.cnpq.br/0172837599844991
;
https://lattes.cnpq.br/8350754524180998
Considering the various types of ceramic tiles used today, the stoneware tile is distinguished by its aesthetic and technical characteristics, such as: very low water absorption (less than 0.5%), high mechanical strength, high abrasion strenght, high chemical and frost strenght. Commonly, a composition of stoneware tile is constituted by homogeneous mixture of plastic clay(s), kaolin, feldspar, quartz and talc of high purity. This work studied the effect of replacing the plastic clay used in the manufacture of this product, typically a clay, by a mudstone of lower refractoriness. Another object of study was to evaluate the influence of the replacement, even partially, the content of feldspar (which is the raw material most suitable flux and used industrially, around 45% by mass) for nepheline, evaluating the technical characteristics achieved in the final product. For this, emphasis was given to the use of different levels and types of trainers from the liquid phase (feldspar and nepheline) in compositions of bath with the mudstone. For comparison it was characterized, by means of physical tests, the linear shrinkage and water absorption (vitrification curve), and flexural strength of a standard composition, reported in the literature, and new compositions. In addition, it was evaluated the cycle and the level of firing (1200 ° C is the temperature industrial average), verifying the possibility of reducing consumption of natural gas, which represents the main energy source of the production process.
Confiabilidade humana: uma abordagem baseada na análise ergonômica do trabalho na operação de um painel de equipamento
(Universidade Federal de São Carlos, 2011-03-03)
Silva, João Alexandre Pinheiro
;
Camarotto, João Alberto
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https://lattes.cnpq.br/1427853773681255
The restructuring of production processes throughout the entire petrochemical chain brought impacts on the labor division, resulting in a series of new demands for knowledge and skills, which are added to old ones, in order to maintain the stability and reliability of the production system, under their responsibility. The objective of this thesis is to build a theoretical framework on human reliability and ergonomics as well as the observation and analysis of an oil refinery production system. It aims to identify conflicts and gaps between the strategies and actions developed by the operators as system reliability maintainance agents in their work daily routine, and the organizational managerial approach for human reliability in the company. In order to achieve these goals, the research approach adopted has the characteristics of literature review that encompasses bibliometrics and content analysis, mixing action research methodology and Ergonomic Workplace Analysis in field research. The literature review identified 304 articles about "human reliability in the ISI Web of Knowledge scientific basis, of which only 50 items are classified in the field of ergonomics (16%). The major research stream on human reliability focuses on nominal scenarios, and therefore, in the ergonomics point of view, focuses on the task, i.e., the prescribed work. Another research stream focus on the real work analysis. The Company studied has classical and a mechanistic point of view focuses on the errors identification and construction barriers through procedures, checklists and other prescription alternatives to improve performance in reliability area. It was evident the fundamental role of the worker as an agent of maintenance and construction of system reliability. There are several strategies adopted by operators to mitigate in practice the gap between prescribed and real work.