43 resultados para CONSTITUENTS

em Universidade Federal do Rio Grande do Norte(UFRN)


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Dutra, R. P. S.; Varela,M. L.; Nascimento, R. M. ; Gomes, U. U. ; Martinelli1, A. E. ; Paskocimas, C. A. Estudo comparativo da queima rápida com a queima tradicional nas propriedades de materiais cerâmicos de base argilosa. Cerâmica [online]. 2009, vol.55, n.333, pp. 100-105. ISSN 0366-6913. doi:Disponivem em: . Acesso em: 04 out. 2010.

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VARELA, M.L. et al. Otimização de uma metodologia para análise mineralógica racional de argilominerais. Cerâmica, São Paulo, n. 51, p. 387-391, 2005.

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The inclusion of local suppliers in production chains has considerable impact on its performance, but most notably in its main actors. The results of this process may be of different kinds and can be analyzed from economic or institutional approaches. This study aimed to verify the existence of different performances of Petrobras due to the inclusion of local suppliers in the oil and gas production chain in the state of Rio Grande do Norte, from the viewpoints of transaction costs and the Institutional Theory. In order to this, were made the characterization of the PROMINP, the description of its actions and results, the mapping of its institutional context of reference, and identification of results obtained by Petrobras in terms of transaction costs and legitimacy. The theoretical framework is based on authors dealing with industrial concentration, as like Marshall, Krugman, Porter and Schmitz, from the sociological perspective of neoinstitucional theory, as like DiMaggio and Powell and Scott and Meyer, and transaction costs, as like Williamson. This is a qualitative research, with data collection done by consulting secondary fonts and semi-structured interviews with nineteen actors of three groups, namely: actors involved in actions of the program, representatives of enterprises and representative of Petrobras. To analyze the content was used the Suchman s model (1995) for categories associated with strategies of legitimation and fourteen variables associated with the three variables assets specificity, bounded rationality and opportunism (Williamson, 1995, 1989) in the case of transaction costs. The results indicate that PROMINP has achieved its objectives by encouraging the increased participation of local companies in the oil and gas production chain, reflecting in the economic development of the state. The Redepetro/RN, fostered and built upon the interaction of the participants, is presented as a solution of continuity to the participation of enterprises in the chain, after the closure of the actions of the program. PROMINP demands responses to coercive, legislative and regulatory pressures of the organizational field, whose institutional context of reference is wide. From the point of view of legitimacy, through strategies to gain cognitive legitimacy and maintaining pragmatic legitimacy, Petrobras can manipulate the environment, ensuring the compliance of the constituents to their technical and institutional demands. Enterprises, in turn, respond to the demands through compliance with technical demands, mainly through the certification of processes, and cultural changes. There aren t clear gains related to the transaction costs, however, gains in legitimacy can be seen as a cumulative capital that can serve as a competitive differential that generates economic gains. In terms of theoretical findings, it was found that, due to its explanatory power for actions that are difficult to explain only in economic terms, Institutional Theory may be used as theoretical support concurrent with other theories. TCE model has limitations in explaining the program actions. In the case, it s emphasized that Petrobras doesn t seek only economic efficiency, but has in its mission the commitment to social development.

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Linseed is an important oilseed consumed raw as nutritional supplement, that although represents a rich source of nutrients, its nutritional value could be impaired due to the presence of antinutritional factors. In this study, protein fractions from raw linseed flour were extracted and isolated being obtained 12% of albumins, 82% of globulins, 5% of glutelins and 1% of prolamins. These proteins were visualized by SDS-PAGE and albumins showed low molecular mass protein bands around 21 kDa and minor bands, similar to that of trypsin inhibitor; Globulins presented protein bands with high molecular masses, which possibly are constituents of multimeric proteins, such as legumins. After determination of the centesimal composition of raw linseed, it was used as exclusive protein source for young rats to evaluate its effect on animal growth. The results showed negative effects on rat growth (weight gain 73% less than the control group) and reduction of intestinal villus (35%), that could be related with in vitro and in vivo globulin digestibility and proteinaceous antinutritional factors (mammalian digestive enzymes inhibitors and lectins) in albumin fraction. Native globulins showed, by SDS-PAGE, low susceptibility in vitro to trypsin and chymotrypsin, however presented high degradation by pancreatin. Thermal treatment of globulins for 5 and 15 minutes at 100ºC improved considerably its digestibility by trypsin and pancreatin. Globulins presented 93.2% in vivo digestibility, similar to the control protein. Albumin fraction had high trypsin inhibition activity (100%) and chymotrypsin inhibition of 28.3%; haemagglutinating activity was not detected. The results of this study indicate the negative action of trypsin inhibitors on animal growth, but can not be discarded its combined action with other antinutritional factors, which could compromise the raw linseed utilization as an alternative food

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The Iota, Kappa and Lambda commercial carrageenans are rarely pure and normally contain varying amounts of the other types of carrageenans. The exact amount of impurity depends on the seaweed source and extraction procedure. Then, different analysis methods have been applied for determination of the main constituents of carrageenans because these three carrageenans are extensively used in food, cosmetic and pharmaceutical industry. The electrophoresis of these compounds proved that the carrageenans are constituted by sulfated polysaccharides. These compounds were characterized by colorimetric methods and was observed that the Lambda carrageenan shown the greater value (33.38%) of sulfate. These polymers were examined by means of 13C NMR spectroscopy and infrared spectra. The polysaccharides consisted mainly of units alternating of sulfated galactoses and anhydrogalactoses. The aim of the study was also to test the inflammatory action of these different polysaccharides. A suitable model of inflammation is acute sterile inflammation of the rat hind limb induced by carrageenan. Paw edema was induced by injecting carrageenans (κ, ι and λ) in saline into the hind paw of a male Wistar rats (175–200 g). The pathway to acute inflammation by carrageenan (kappa, iota and lambda) were expressed as time-edema dependence and measured by paw edema volume. For this purpose, was used an apparatus (pakymeter), which makes it possible to measure the inflammation (swelling of the rat foot) with sufficient accuracy. The results showed that κ-carrageenan (1%) have an edema of 3.7 mm and the paw edema increase was time and dose dependent; the ι-carrageenan (0.2%) caused an edema of 4 mm and the λ-carrageenan (1%) caused an edema of 3.6 mm. Other model was used in this study based in the inflammation of pleura for comparatives studies. Injection of carrageenans into the pleural cavity of rat induced an acute inflammatory response characterized by fluid accumulation in the pleural cavity, a large number of neutrophils and raised NO production. The levels of NO were measured by Griess reactive. The ι-carrageenan caused the greater inflammation, because it has high concentration of nitrite/nitrate (63.478 nmoles/rat), exudato volume (1.52 ml) and PMNs (4902 x 103 cells). Quantitative evaluation of inflammations of rats is a useful and important parameter for the evaluation of the efficacy of anti-inflammatory drugs

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The main objective is to analyze the abrasive wear resistance to the low stress of the elements that make up the organs of road machinery that are exposed directly to contact with abrasives. These samples were analyzed after these elements are coated superficially by the process of welding electrode coated with (SAER) and the manual process of coating type LVOF thermal spraying. As well, is to provide suggestions for a better recovery and return of these elements, which are reducing costs and avoiding downtime in the fronts of service. The samples were made from a substrate of carbon ABNT 1045 tempered steel, following the same specifications and composition of metals and alloys of constituents was followed the standard governing the dimensions of these samples and in accordance with the corresponding size. The results were evaluated by testing the hardness, abrasion resistance to wear by the low stress and the loss of volume involving the microstructure of coatings analyzed

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Nowadays the environmental issues are increasingly highlighted since the future of humanity is dependent on the actions taken by man. Major efforts are being expended in pursuit of knowledge and alternatives to promote sustainable development without compromising the environment. In recent years there has been a marked growth in the development of reinforced composite fiber plants, as an alternative for economic and ecological effects, especially in the substitution of synthetic materials such as reinforcement material in composites. In this current study the chemical- physical or (thermophysics )characteristics of the babassu coconut fiber, derived from the epicarp of the fruit (Orbignyda Phalerata), which the main constituents of the fiber: Klason lignin, insoluble, cellulose, holocellulose, hemicellulose and the content of ash and moisture will be determined. A study was conducted about the superficial modification of the fibers of the epicarp babassu coconut under the influence of chemical treatment by alkalinization, in an aqueous solution of NaOH to 2.5% (m/v) and to 5.0% to improve the compatibility matrix / reinforcement composite with epoxy matrix. The results of the changes occurred in staple fibers through the use of the techniques of thermogravimetric analyses (TG) and differential scanning calorimetry (DSC). The results found on thermal analysis on samples of fiber without chemical treatment (alkalinities), and on fiber samples treated by alkalinization show that the proposed chemical treatment increases the thermal stability of the fibers and provides a growth of the surface of area fibers, parameters that enhance adhesion fiber / composite. The findings were evaluated and compared with published results from other vegetable fibers, showing that the use of babassu coconut fibers has technical and economic potential for its use as reinforcement in composites

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This employment has the function the utilization of mango seeds Tommy Atkins, like starch source to obtain biopolymers and fibers source and nanowhiskers cellulose also, that will be use like reinforcing fillers in micro and nanobiocomposites polymeric. The fibers in natura removed from tegument mango seed were characterized, as weel as the treated fibers and nanowhiskers of cellulose extracted from them. The starch extracted from seed s almond showed a good performance (32%) and a high purity. The chemicals analyzes, of crystallinity and morphological of the fibers in natura, treated fibers and nanowhiskers of cellulose confirmed the efficacy of the chemical treatement performed to remove amorphous constituents (hemicellulose and lignina). The thermoplastic starch (TPS) obtained from two sources, corn starch and starchy material mango, was produced in a twin screw extruder with compositon mass of 62,5% of starch, 9,4% of water and 28,1% of glycerol. The starch material mango was the main objective of this work for the production of biodegradable materials, and the starch corn was utilized during the production stage to evaluate the processability of the starch and use as parameter for comparison, according of being a conventional source for obtaining conventional comercial starch. The incorporation of fibers (6% in mass) and nanowhiskers cellulose (1% in mass) in matrix of TPS to obtain composite and nanocomposite, respectively, it was performed in single screw extruder. The biocomposites and bionanocomposites polymeric were obtained and the TPS from starchy material mango presented better results of thermal and mechanicals properties when compared to TPS corn starch. Concludes that the sediment generated of the agroindustrial processing mango used presents potencial to producing of biodegradables materials

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To produce porcelain tiles fluxing agents are used in order to obtain a liquid phase during firing. This liquid phase fills the pores decreasing porosity, water absorption and contributes to material densification. In the porcelain tiles industry, feldspar is the main flux material used, with quantities ranging between 35 and 50%. Studies focus on the discovery of materials with flux characteristics that can reduce the consumption of feldspar by porcelain tiles industry. In this context, the coffee husk ashes, a residue obtained when coffee husks are burned to produce heat for the dryers during the processing of the green fruit, have as main chemical constituents potassium, calcium and magnesium, giving them characteristics of fluxing material. Brazil is the largest coffee producer in the world and is responsible for over 30% of the world s production. In this work a physical treatment of coffee husk ash was carried out in order to eliminate the organic matter and, after this, two by-products were obtained: residual wastes R1 and R2. Both residues were added separately as single fluxes and also in association with feldspar in mixtures with raw materials collected in a porcelain industry located in Dias d Ávila-Ba. The addition of these residues aimed to contribute to the reduction of the consumption of feldspar in the production of porcelain tiles. Specimens were produced with dimensions of 60 mm x 20 mm x 6 mm in an uniaxial die with compacting pressure of 45 MPa. The samples were heated to a temperature of 1200 °C, for 8 minutes. Tests were performed to characterize the raw materials by XRF, XRD, particle size analysis, DTA and TGA and, additionally, the results of the physical properties of water absorption, apparent porosity, linear shrinkage, density, dilatometry, flexural strength and SEM of sintered body were analyzed. Additions of less than 8% of the residue R1 contributed to the decrease of porosity, but the mechanical strength of the samples was not satisfactory. Additions of 5% the R2 residue contributed significantly to decrease the water absorption and apparent porosity, and also to increase the mechanical strength. Samples with addition of feldspar associated with the R2 residue, in proportions of 6.7% of R2 and 6.7% of feldspar, led to results of water absorption of 0.12% and mechanical strength of 46 MPa, having parameters normalized to the manufacture of porcelain stoneware tiles

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Boron is a semi-metal present in certain types of soils and natural waters. It is essential to the healthy development of plants and non-toxic to humans, depending on its concentration. It is used in various industries and it s present in water production coming from oil production. More specifically in Rio Grande do Norte, one of the largest oil producers on shore of Brazil, the relationship water/oil in some fields becomes more than 90%. The most common destination of this produced water is disposal in open sea after processing to meet the legal specification. In this context, this research proposes to study the extraction of boron in water produced by microemulsion systems for industrial utilization. It was taken into account the efficiency of extraction of boron related to surfactant (DDA and OCS, both characterized by FT-IR), cosurfactant (butanol and isoamyl alcohol), organic phase (kerosene and heptanes) and aqueous phase (solution of boron 3.6 ppm in alkaline pH). The ratio cosurfactant/ surfactant used was four and the percentage of organic phases for all points of study was set at 5%. It was chosen points with the highest percentage of aqueous phase. Each system was designed for three points of different compositions in relation to the constituents of a pseudoternary diagram. These points were chosen according to studies of phase behavior in pseudoternary diagrams made in previous studies. For this research, points were chosen in the Winsor II region. The excess aqueous solution obtained in these systems was separated and analyzed by ICP OES. For the data set obtained, the better efficiency in the extraction of boron was obtained using the system with DAC, isoamyl alcohol and heptanes, which extracted 49% in a single step. OCS was not viable to the extraction of boron by microemulsion system in the conditions defined in this study

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This master thesis aims at developing a new methodology for thermochemical degradation of dry coconut fiber (dp = 0.25mm) using laboratory rotating cylinder reactor with the goal of producing bio-oil. The biomass was characterized by infrared spectroscopy with Fourier transform FTIR, thermogravimetric analysis TG, with evaluation of activation energy the in non-isothermal regime with heating rates of 5 and 10 °C/min, differential themogravimetric analysis DTG, sweeping electron microscopy SEM, higher heating value - HHV, immediate analysis such as evaluated all the amounts of its main constituents, i.e., lignin, cellulose and hemicelluloses. In the process, it was evaluated: reaction temperature (450, 500 and 550oC), carrier gas flow rate (50 and 100 cm³/min) and spin speed (20 and 25 Hz) to condensate the bio-oil. The feed rate of biomass (540 g/h), the rotation of the rotating cylinder (33.7 rpm) and reaction time (30 33 min) were constant. The phases obtained from the process of pyrolysis of dry coconut fiber were bio-oil, char and the gas phase non-condensed. A macroscopic mass balance was applied based on the weight of each phase to evaluate their yield. The highest yield of 20% was obtained from the following conditions: temperature of 500oC, inert gas flow of 100 cm³/min and spin speed of 20 Hz. In that condition, the yield in char was 24.3%, non-condensable gas phase was 37.6% and losses of approximately 22.6%. The following physicochemical properties: density, viscosity, pH, higher heating value, char content, FTIR and CHN analysis were evaluated. The sample obtained in the best operational condition was subjected to a qualitative chromatographic analysis aiming to know the constituents of the produced bio-oil, which were: phenol followed by sirigol, acetovanilona and vinyl guaiacol. The solid phase (char) was characterized through an immediate analysis (evaluation of moisture, volatiles, ashes and fixed carbon), higher heating value and FTIR. The non-condensing gas phase presented as main constituents CO2, CO and H2. The results were compared to the ones mentioned by the literature.

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The program PROBIODIESEL from the Ministry of Science and Technology has substantially increased glycerine, obtained as a sub-product of biodiesel production process, making it necessary to seek alternatives for the use of this co-product. On the other hand, herbicides although play a role of fundamental importance in the agricultural production system in force, have been under growing concern among the various segments of society because of their potential environmental risk. In this work, we used glycerin in microemulsion systems for application of herbicides, to improve efficiency and lower environmental pollution caused by the loss of those products to the environment. To obtain the systems of microemulsinados were used Unitol L90 NP and Renex 40 as surfactants, butanol as co-surfactant, coconut oil as oil phase and aqueous phase as we used solutions of glycerin + water. Through the determination of phase diagrams, the microemulsion region was found in the system E (L90 Unitol, coconut oil and glycerin + water 1:1). Three points were chosen to the aqueous phase rich in characterization and application in the solubilization of glyphosate and atrazine. Three experiments were performed in Horta, Department of Plant Sciences, Plant Science Sector, UFERSA, Mossoró-RN. The first experiment was conducted in randomized complete blocks with 20 treatments and four replications. The treatments consisted of five doses of the herbicide glyphosate (0.0, 0.45, 0.9, 1.35 and 1.8 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity of Brachiaria brizantha was measured at 7, 14, 28 and 60 DAA (days after application). At 60 DAA, we evaluated the biomass of plants. The second experiment was developed in randomized complete blocks with 20 treatments and four repetitions. The treatments consisted of five doses of the herbicide atrazine (0.0, 0.4, 0.8, 1.6 and 2.4 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity on Zea mays and Talinum paniculatum was evaluated at 2, 7, 20 DAA. The experiment III was developed in randomized complete blocks with 16 treatments and three repetitions. The treatments consisted of 16 combinations among the constituents of the microemulsion: Unitol L90 surfactant (0.0, 1.66, 5.0, 15 %) and glycerin (0.0, 4.44, 13.33 and 40.0 %). The phytotoxicity on Zea mays was evaluated at 1, 7 and 14 DAA. At 14 DAA, we evaluated the biomass of plants. The control plants using the microemulsions was lower than in the water due to the poisoning caused by the initial microemulsions in the leaves of the plants, a fact that hinders the absorption and translocation of the herbicide. There was no toxicity in Zea mays plants caused by the herbicide, however, were highly intoxicated by microemulsions. T. paniculatum was better controlled in spraying with the microemulsions, regardless of the dose of the herbicide. The glycerine did not cause plant damage. Higher poisoning the plants are caused by tensoactive Unitol L90 and higher rates occur with the use of higher concentrations of surfactant and glycerin, or microemulsion. The microemulsions used hampered the action of glyphosate in controlling B. brizantha and caused severe poisoning in corn, and these poisonings attributed mainly to the action of surfactant

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The worldwide concern regarding the use of sustainable energy and preserving the environment are determining factors in the search for resources and alternative sources of energy and therefore fuel less aggressive nature. In response to these difficulties Biodiesel has emerged as a good solution because it is produced from renewable sources, produces burns cleaner and is easily reproducible. This work was synthesized with biodiesel oil, sunflower via homogeneous catalysis in the presence of KOH, with and without the use of BHT and subsequently added to the blends BX (a proportion of biodiesel X = 5, 10, 15 and 20 %). Atmospheric distillation of the analysis, performed in blends with and without BHT were collected residue generated by each sample and performed a study heat from the thermogravimetric analysis at a heating rate of 10 °C*min-1, nitrogen atmosphere and heating to 600 °C. According to the specifications of Resolution N 7/2008 for biodiesel, it was found that the synthesized material was in accordance with the specifications. For blends showed that the samples are in accordance with the Resolution of ANP N 42/2009. From the TG / DTG curves of the samples of biodiesel, blends and waste can be seen that these show a single loss of thermal decomposition concerning constituents present in each sample. The blends without BHT with ratios of 5%, 10% and 15% biodiesel showed a lower amount of waste (1,07%; 1,09% e 1,10%) to mineral diesel (1,15%). Therefore, it is concluded that the addition of biodiesel with diesel mineral can improve some physico-chemical parameters, but also, depending on the added amount, decreasing the amount of waste generated. This fact is of great importance because the carbonaceous residue can cause problems in mechanical equipment and parts for vehicles, causing more frequent maintenance, and this is not desirable

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The growing world demand for energy supplied by fossil fuels, a major contributor to the emission of pollutants into the atmosphere and causing environmental problems, has been encouraging governments and international organizations to reflect and encourage the use of alternative renewable sources. Among these new possibilities deserves attention biodiesel, fuel cleaner and easy to reproduce. The study of new technologies involving that source is necessary. From this context, the paper aims at analyzing the thermal stability by thermogravimetric analysis, of the waste generated from atmospheric distillation of mixtures with ratios of 5, 10, 15 and 20% palm biodiesel in diesel with and without addition of BHT antioxidant. It was synthesized biodiesel through palm oil, via homogeneous catalysis in the presence of KOH, with and without the use of BHT and subsequently added to the diesel common indoor type (S1800) from a gas station BR. The diesel was already added with 5% biodiesel, and thus the proportions used for these blends were subtracted from the existing ratio in diesel fuel, resulting in the following proportions palm oil biodiesel: 0% (B5), 5% (B10), 10 % (B15) and 15% (B20). From atmospheric distillation analysis, performed in mixtures with and without BHT were collected residue generated by each sample and performed a thermal study from the thermogravimetric analysis at a heating rate of 10 °C.min-1, nitrogen atmosphere and heating to 600 ° C. According to the specifications of Resolution No. 7/2008 for biodiesel, it was found that the material was synthesized in accordance with the specifications. For mixtures, it was noted that the samples were in accordance with the ANP Resolution No. 42/2009. Given the TG / DTG curves of the samples of waste mixtures with and without BHT antioxidant was able to observe that they showed a single stage of thermal decomposition attributed to decomposition of heavy hydrocarbons and esters and other heavier constituents of the waste sample weighed. The thermal behavior of residues from atmospheric distillation of mixtures of diesel / biodiesel is very important to understand how this affects the proper functioning of the engine. A large amount of waste can generate a high content of particulate material, coke formation and carbonaceous deposits in engine valves, compromising their performance

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The uses of radiobiocomplexes labeled with technetium-99m contributed to health science advances. Stannous chloride (SnCl2) has been used as a reducing agent for the labeling process. Cytotoxic and genotoxic effect of the SnCl2 have been described in several studies and with this experimental models alterations in molecular and cellular level can be evaluated. In the last years the physicals therapists acquired new devices which emits electromagnetic radiation such us Extremely Low Frequency Pulsated Electromagnetic Fields (E.L.F. P.E.M.F.), radiofrequency, Intense Pulsed Light (I.P.L.) and others which emits sonic waves such us Biorresonance. Scientific evidence of the effects and dosage is important to protect public health and to reach exposition levels that result in significant biological effects. The aim of this project is to verify the effects of these physical agents in plasmid DNA and E. coli AB1157 cultures in presence or absence of SnCl2 and the effects in blood constituents labeled with technetium-99m. Wistar rats blood was exposed to the cited sources and the labelling of blood constituents with 99mTc was carried through. Cultures of E. coli AB1157 and plasmidial samples DNA had been also exposed the physical agents. The results suggest that these agents are capable of altering neither the survival of E. coli cells or plasmid DNA electrophoresis mobility. The multidiscipline character was clearly in this study due the interaction between Nuclear Medicine department of the UERJ and the Laboratory of Physical Agents of the Maimonides University in Argentina until the union between the teacher (biomedical and physiotherapist) and student (physiotherapist), besides collaborators of the area of Physics and Biology, promoting new ideas and perspectives and also adding the knowledge of different areas and origins