6 resultados para ATM desdentado
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
Seeking a greater appreciation of cheese whey was developed to process the hydrogenation of lactose for the production of lactitol, a polyol with high added value, using the catalyst Ni / activated carbon (15% and 20% nickel), the nitride Mo2N, the bimetallic carbide Ni-Mo/ activated carbon and carbide Mo2C. After synthesis, the prepared catalysts were analyzed by MEV, XRD, laser granulometry and B.E.T. The reactor used in catalytic hydrogenation of lactose was the type of bed mud with a pressure (68 atm), temperature (120 oC) and stirring speed (500 rpm) remained constant during the experiments. The system operated in batch mode for the solid and liquid and semi-continuous to gas. Besides the nature of the catalyst, we studied the influence of pH of reaction medium for Mo2C carbide as well as evaluating the character of the protein inhibitor and chloride ions on the activity of catalysts Ni (20%)/Activated Carbon and bimetallic carbide Ni-Mo/Activated Carbon. The decrease in protein levels was performed by coagulation with chitosan and adsorption of chloride ions was performed by ion exchange resins. In the process of protein adsorption and chloride ions, the maximum percentage extracted was about 74% and 79% respectively. The micrographs of the powders of Mo2C and Mo2N presented in the form of homogeneous clusters, whereas for the catalysts supported on activated carbon, microporous structure proved impregnated with small particles indicating the presence of metal. The results showed high conversion of lactose to lactitol 90% for the catalyst Ni (20%)/Activated Carbon at pH 6 and 46% for the carbide Mo2C pH 8 (after addition of NH4OH) using the commercial lactose. Monitoring the evolution of the constituents present in the reaction medium was made by liquid chromatography. A kinetic model of heterogeneous Langmuir Hinshelwood type was developed which showed that the estimated constants based catalysts promoted carbide and nitride with a certain speed the adsorption, desorption and production of lactitol
Resumo:
The wet oxidation of organic compounds with CO2 and H2O has been demonstrated to be an efficient technique for effluent treatment. This work focuses on the synthesis, characterization and catalytic performance of Fe-MnO2/CeO2, K-MnO2/CeO2/ palygorskite and Fe/ palygorskite toward the wet oxidative degradation of phenol. The experiments were conducted in a sludge bed reactor with controlled temperature, pressure and stirring speed and sampling of the liquid phase. Experiments were performed on the following operating conditions: temperature 130 ° C, pressure 20.4 atm, catalyst mass concentration of 5 g / L initial concentration of phenol and 0.5 g / L. The catalytic tests were performed in a slurry agitated reactor provided with temperature, pressure and agitation control and reactor liquid sampling. The influences of iron loaded on the support (0.3; 7 and 10%, m/m) and the initial pH of the reactant medium (3.1; 6.8; 8.7) were studied. The iron dispersion on the palygorskite, the phase purity and the elemental composition of the catalyst were evaluated by X-Ray Difraction (XRD), Scanning Electron Microscopy (SEM) and X-Ray Flourescence (XRF). The use of palygorskite as support to increase the surface area was confirmed by the B.E.T. surface results. The phenol degradation curves showed that the Fe3+ over palygorskite when compared with the other materials tested has the best performance toward the (Total Organic carbonic) TOC conversion. The decrease in alkalinity of the reaction medium also favors the conversion of TOC. The maximum conversion obtained from the TOC with the catalyst 3% Fe / palygorskite was around 95% for a reaction time of 60 minutes, while reducing the formation of acids, especially acetic acid. With products obtained from wet oxidation of phenol, hydroquinone, p-benzoquinone, catechol and oxalic acid, identified and quantified by High Performance Liquid Chromatography was possible to propose a reaction mechanism of the process where the phenol is transformed into the homogeneous and heterogeneous phase in the other by applying a kinetic model, Langmuir-Hinshelwood type, with evaluation of kinetic constants of different reactions involved.
Resumo:
For a complete comprehension of the effect of tooth loss is necessary to listen to the patients that have it. This study, of qualitative approach, investigate, in the dental history of users of SUS, listening to his/her experiences with the services of dental care, the reason that lead his/her to dental lost and the repercussion of this in his/her life. The collect of data was made by narrative interview, obeying to a pre-defined schema. The subjects interviewed were six (three of urban zone and three of rural zone), all of them were users of Family Health Units. The criterions of inclusion were the followings: the presence of tooth lost (total lost in both dental arch or in one of them, or partial lost in at least six elements in one of the arches); age between 25 and 59; male or female; to live in municipal district of São Tomé/RN or Natal/RN. Based on previous interviews was elaborated the odontological history of each patient. Such narratives, systemized in odontological history, were analyzed taking as base the studies of Souza71 and the proposal of Schutze, suggested for Jovchelovitch, Bauer34. The results show that toothache was the main reason for the search of odontological care. The patients confront the ache with home-made medicaments, allopathic ones, and searching for dental care. The searching for exodontics was stimulated for geographic access difficulties or for repressed demand, which as a result produced the aggravation of the lesions and the discredit in restoration s treatment. The self-care practice of tooth-brush with juá or toothpaste and the controlled ingestion of sugar was not sufficient to avoid dental lost. Guilty sentiments were identified in relation with lack of care with teeth. The acceptance of dental lost as a natural factor is an important motivation in lack of pain and in the belief that it was a simple part of life in old age. Life with dental prosthesis makes clear the difference between which was natural and which was unnatural, and difficulties with the prosthesis appeared. The limitation of the prosthesis in its functional aspect can be compensated by esthetic restitution, making possible smiling expression. Starting with this study and considering the high number of dental lost, mainly in low-rent population, which live with toothless limitations or bad-quality prosthesis which do not rehabilitate adequately, we suggested the realization of qualitative researches which include, also, another actors in heath care services such as professionals and administrators
Resumo:
There is a lack of clinical studies evaluating techniques of functional impression for partially edentulous arches. The aim of this double-blind non-randomized controlled clinical trial was to compare the efficacy of altered cast impression (ACI) and direct functional impression (DFI) techniques. The efficacy was evaluated regarding the number of occlusal units on denture teeth, mucosa integrity at 24-hour follow-up and denture base extension. The sample included 51 patients (female and male) with mean age of 58.96 years treated at Dental Department of UFRN. The patients, exhibiting edentulous maxilla and mandibular Kennedy class I, were divided into two groups (group ACI, n=29; group DFI, n=22). Clinical evaluation was based on the number of occlusal units on natural and/or artificial teeth, mucosa integrity at 24-hour follow-up, and denture base extension. Statistical analysis was conducted using the software SPSS 17.0® (SPSS Inc., Chicago, Illinois). Student T-test was used to reveal association between number of occlusal units and impression technique while chi-square test showed association between mucosa integrity and impression technique. Fischer s exact test was applied for association between denture base extension and impression technique at 95% level of significance. No significant difference was observed between the groups regarding number of occlusal units, mucosa integrity and denture base extension. The altered cast technique did not provide significant improvement in comparison to the direct technique when the number of occlusal units, mucosa integrity and denture base extension
Resumo:
The modern industrial progress has been contaminating water with phenolic compounds. These are toxic and carcinogenic substances and it is essential to reduce its concentration in water to a tolerable one, determined by CONAMA, in order to protect the living organisms. In this context, this work focuses on the treatment and characterization of catalysts derived from the bio-coal, by-product of biomass pyrolysis (avelós and wood dust) as well as its evaluation in the phenol photocatalytic degradation reaction. Assays were carried out in a slurry bed reactor, which enables instantaneous measurements of temperature, pH and dissolved oxygen. The experiments were performed in the following operating conditions: temperature of 50 °C, oxygen flow equals to 410 mL min-1 , volume of reagent solution equals to 3.2 L, 400 W UV lamp, at 1 atm pressure, with a 2 hours run. The parameters evaluated were the pH (3.0, 6.9 and 10.7), initial concentration of commercial phenol (250, 500 and 1000 ppm), catalyst concentration (0, 1, 2, and 3 g L-1 ), nature of the catalyst (activated avelós carbon washed with dichloromethane, CAADCM, and CMADCM, activated dust wood carbon washed with dichloromethane). The results of XRF, XRD and BET confirmed the presence of iron and potassium in satisfactory amounts to the CAADCM catalyst and on a reduced amount to CMADCM catalyst, and also the surface area increase of the materials after a chemical and physical activation. The phenol degradation curves indicate that pH has a significant effect on the phenol conversion, showing better results for lowers pH. The optimum concentration of catalyst is observed equals to 1 g L-1 , and the increase of the initial phenol concentration exerts a negative influence in the reaction execution. It was also observed positive effect of the presence of iron and potassium in the catalyst structure: betters conversions were observed for tests conducted with the catalyst CAADCM compared to CMADCM catalyst under the same conditions. The higher conversion was achieved for the test carried out at acid pH (3.0) with an initial concentration of phenol at 250 ppm catalyst in the presence of CAADCM at 1 g L-1 . The liquid samples taken every 15 minutes were analyzed by liquid chromatography identifying and quantifying hydroquinone, p-benzoquinone, catechol and maleic acid. Finally, a reaction mechanism is proposed, cogitating the phenol is transformed into the homogeneous phase and the others react on the catalyst surface. Applying the model of Langmuir-Hinshelwood along with a mass balance it was obtained a system of differential equations that were solved using the Runge-Kutta 4th order method associated with a optimization routine called SWARM (particle swarm) aiming to minimize the least square objective function for obtaining the kinetic and adsorption parameters. Related to the kinetic rate constant, it was obtained a magnitude of 10-3 for the phenol degradation, 10-4 to 10-2 for forming the acids, 10-6 to 10-9 for the mineralization of quinones (hydroquinone, p-benzoquinone and catechol), 10-3 to 10-2 for the mineralization of acids.
Resumo:
The instrumental teaching in Brazil has been more widely studied by music education in the last years, becoming a significative scientific investigation field. This work is focusing on analysis of the instrument teaching reality, considering more specifically the guitar teaching. In a timely manner, approaches the reality of the guitar teaching from the Universidade Federal do Rio Grande do Norte (Federal University of Rio Grande do Norte – UFRN), considering specific instrument courses in this institution. Thus, the present work was guided by the aim of understanding conceptions, contents and didactic and methodological perspectives that constitute the teaching and learning of the guitar at UFRN. To reach this main aim, we sought to verify, in general: 1) the theoretical, methodological and content perspectives that underlie guitar formation in the music courses of the UFRN; 2) the functions and the aims of the guitar disciplines in the Courses; 3) the profile of the guitar disciplines' professors; 4) the demands of the subjects directly involved in these proposals of musical education; and, 5) the conceptions about formation practices and teaching methodologies that characterize the docent action. In accordance with the aims, the methodological guidance was based on the qualitative paradigm. Thus, data collection procedures involved were: bibliographical and documentary research and interviews with three professors who taught in guitar disciplines during the semester of 2014.1 on the mentioned courses. Then, these data were systematically organized and analyzed in line with the research characteristics presented here. The results of the research evidenced the concepts, contents and didactic and methodological perspectives in the context of teaching and learning guitar in the studied empirical field. In this context, we perceive a relation between the demands of teaching and learning tool in the study field and the ones evidenced in the literature. The results demonstrated that the professors’ professional tragetory is associated with their influences from the initial musical formation and their guitar learning since they related conceptions that reflected aspects formation, sometimes converging sometimes divergente. The contentes, methodologies and general aspects are made based on parameters that demonstrate alignment with the perspectives of guitar teaching and learning in the contemporary world to the instrumental player formation. Thus, the study gave a broader diagnosis about the guitar teaching reality, demonstrating the diferences and the singularities between the Technical Course and the Course of Bachelor in Music at UFRN. Thereby, this study provides importante contribution to music education, mainly, through its reflections about the guitar pedagogy.