Avaliação termoanalítica da eficiência de antioxidantes na estabilidade oxidativa do biodiesel de mamona

The biodiesel is defined as the mono-alkyl ester derived from long-chain fatty acids, from renewable sources such as vegetable oils or animal fat, whose use is associated with the replacement of fossil fuels in diesel engine cycle. The biodiesel is susceptible to oxidation when exposed to air and this process of oxidation affects the quality of fuel, mainly due to long periods of storage. Because of this, the oxidation stability has been the focus of numerous researches since it directly affects the producers, distributors and users of fuel. One of the possibilities to increase the resistance of biodiesel is the autoxidation treatment with inhibitors of oxidation. The antioxidants can be used as potential inhibitors of the effects of oxidation on the kinematic viscosity and the index of acidity of biodiesel, thereby increasing oxidative stability. This work aims to examine the efficiency of antioxidants, α-tocopherol and butylated hydroxy-toluene (BHT), added the biodiesel content of remembrance through Pressurized-Differential Scanning Calorimetry (P-DSC), Thermogravimetry (TG) and Petrology. The results showed that the use of antioxidant BHT, at the concentration of 2000ppm, increased resistance to oxidation of the biodiesel and oxidative induction time (OIT), which is a better result as antioxidant than the α-tocopherol. With the thermogravimetric analysis, it was observed that the biodiesel presented an initial decomposition temperature of lower tendency than that of oil, demonstrating to be more volatile, bearing great similarity to the diesel and being characterized as an alternative fuel. The rheological analysis indicated that each sample of biodiesel behaved as a Newtonian fluid

Dynamics of meso and thermo citrate synthases with implicit solvation

The dynamics of hydration of meso and thermo citrate synthases has been investigated using the EEF1 methodology implemented with the CHARNM program. The native enzymes are composed of two identical subunits, each divided into a small and large domain. The dynamics behavior of both enzymes at 30 degrees C and 60 degrees C has been compared. The results of simulations show that during the hydration process, each subunit follows a different pathway of hydration, in spite of the identical sequence. The hydrated structures were compared with the crystalline structure, and the root mean square deviation (RMSD) of each residue along the trajectory was calculated. The regions with larger and smaller mobility were identified. In particular, helices belonging to the small domain are more mobile than those of the large domain. In contrast, the residues that constitute the active site show a much lower displacement compared with the crystalline structure. Hydration free energy calculations point out that Thermoplasma acidophilum citrate synthase (TCS) is more stable than chicken citrate synthase (CCS), at high temperatures. Such result has been ascribed to the higher number of superficial charges in the thermophilic homologue, which stabilizes the enzyme, while the mesophilic homologue denatures. These results are in accord with the experimental found that TCS keeps activity at temperatures farther apart from the catalysis regular temperature than the CCS. (c) 2005 Wiley Periodicals, Inc.

Eficiência do processo de obtenção do biodiesel de girassol usando o catalisador KNO3/Al2O3

It is known that the head office world energetics is leaning in the fossil fuels. However, the world panorama is changing quickly, for linked reasons to three of the humanity's great concerns in that century beginning: environment, global economy and energy. The biodiesel production is based on the transesterificação of vegetable oils or animal fats, using catalysts homogeneous or heterogeneous. The process of heterogeneous transesterificação presents lower conversions in comparison with the homogeneous, however, it doesn't present corrosion problems and it reduces to the occurrence of parallel reactions as saponification. In this sense, this work has for purpose the synthesis of a heterogeneous catalyst, KNO3/Al2O3, that soon afterwards was used in the reaction of transesterificação of the oil of the Helianthus annuus L. (sunflower). The solid materials (it supports and catalyst) they were analyzed by diffraction of ray-X (XRD) and electronic microscope of sweeping (MEV). After the analysis of Al2O3, a structure monophase amorphous tetragonal was verified, with characteristic patterns of that material, what could not be visualized in the difratograma of the catalyst. The biodiesel obtained with 4% wt. of KNO3/Al2O3 it was what obtained a better cinematic viscosity 8,3 mm2/s, comparing with the norms of ANP, and it also presented the best conversion tax in ethyl ésteres, in accordance with the quantitative measure starting from TG, that was of 60%. While the biodiesel with 6% wt. and with 8% wt. of KNO3/Al2O3 it was it that no transesterificou, because it was observed in the analysis termogravimétrica of those two materials, a single thermal event, that it corresponds the decomposition or volatilization of the triglycerides

Remoção, por flotação, de óleo em águas produzidas na indústria de petróleo: eficiência e modelagem do processo

The separation oil-water by the use of flotation process is characterized by the involvement between the liquid and gas phases. For the comprehension of this process, it s necessary to analyze the physical and chemical properties command float flotation, defining the nature and forces over the particles. The interface chemistry has an important role on the flotation technology once, by dispersion of a gas phase into a liquid mixture the particles desired get stuck into air bubbles, being conduced to a superficial layer where can be physically separated. Through the study of interface interaction involved in the system used for this work, was possible to apply the results in an mathematical model able to determine the probability of flotation using a different view related to petroleum emulsions such as oil-water. The terms of probability of flotation correlate the collision and addition between particles of oil and air bubbles, that as more collisions, better is the probability of flotation. The additional probability was analyzed by the isotherm of absorption from Freundlich, represents itself the add probability between air bubbles and oil particles. The mathematical scheme for float flotation involved the injected air flow, the size of bubbles and quantity for second, the volume of float cell, viscosity of environment and concentration of demulsifier. The results shown that the float agent developed by castor oil, pos pH variation, salt quantity, temperature, concentration and water-oil quantity, presented efficient extraction of oil from water, up to 95%, using concentrations around 11 ppm of demulsifier. The best results were compared to other commercial products, codified by ―W‖ and ―Z‖, being observed an equivalent demulsifier power between Agflot and commercial product ―W‖ and superior to commercial product ―Z‖

Eficiência de extração de cobre e níquel utilizando sistemas microemulsionados bifásicos e trifásicos

The environmental impact due to the improper disposal of metal-bearing industrial effluents imposes the need of wastewater treatment, since heavy metals are nonbiodegradable and hazardous substances that may cause undesirable effects to humans and the environment. The use of microemulsion systems for the extraction of metal ions from wastewaters is effective when it occurs in a Winsor II (WII) domain, where a microemulsion phase is in equilibrium with an aqueous phase in excess. However, the microemulsion phase formed in this system has a higher amount of active matter when compared to a WIII system (microemulsion in equilibrium with aqueous and oil phases both in excess). This was the reason to develop a comparative study to evaluate the efficiency of two-phases and three-phases microemulsion systems (WII and WIII) in the extraction of Cu+2 and Ni+2 from aqueous solutions. The systems were composed by: saponified coconut oil (SCO) as surfactant, n-Butanol as cosurfactant, kerosene as oil phase, and synthetic solutions of CuSO4.5H2O and NiSO4.6H2O, with 2 wt.% NaCl, as aqueous phase. Pseudoternary phase diagrams were obtained and the systems were characterized by using surface tension measurements, particle size determination and scanning electron microscopy (SEM). The concentrations of metal ions before and after extraction were determined by atomic absorption spectrometry. The extraction study of Cu+2 and Ni+2 in the WIII domain contributed to a better understanding of microemulsion extraction, elucidating the various behaviors presented in the literature for these systems. Furthermore, since WIII systems presented high extraction efficiencies, similar to the ones presented by Winsor II systems, they represented an economic and technological advantage in heavy metal extraction due to a small amount of surfactant and cosurfactant used in the process and also due to the formation of a reduced volume of aqueous phase, with high concentration of metal. Considering the reextraction process, it was observed that WIII system is more effective because it is performed in the oil phase, unlike reextraction in WII, which is performed in the aqueous phase. The presence of the metalsurfactant complex in the oil phase makes possible to regenerate only the surfactant present in the organic phase, and not all the surfactant in the process, as in WII system. This fact allows the reuse of the microemulsion phase in a new extraction process, reducing the costs with surfactant regeneration

Eficiência mastigatória e impacto da saúde oral na qualidade de vida em pacientes reabilitados com próteses totais removíveis implanto-suportadas

Edentulous patients with complaint about mandibular conventional denture might experience poor masticatory function and negative impact of oral health on quality of life. The aim of this controlled clinical trial was to evaluate the effect of mandibular overdenture on oral health-related quality of life and masticatory efficacy in patients wearing mandibular complete dentures. The edentulous patients (n=16) were rehabilitated with new maxillary and mandibular complete dentures and, after 3 months, mandibular overdentures retained by 2 implants (bar-clip system) were fabricated. The Brazilian version of OHIP-Edent questionnaire was used to assess the oral healthrelated quality of life. Masticatory efficacy was evaluated through a colorimetric method with chewing capsules. The mean OHIP-Edent score was 8.5 with conventional dentures and 2.0 with mandibular overdenture, which means a positive impact of oral health on quality of life with overdentures (p=0.001). The mean absorbance for masticatory efficacy was 0.025 for conventional dentures and 0.073 for overdentures. There was statistically significant difference for masticatory efficacy before and after implants rehabilitation (p=0.003). However, there was no correlation between masticatory efficacy and OHIP (p>0.05). So, mandibular overdenture retained by 2 implants improved the quality of life and masticatory efficacy of edentulous patients with complaint about mandibular conventional complete dentures

Avaliação da eficiência da técnica de obturação pela compressão hidrùlica vertical após instrumentação automatizada

The purpose of this study was to evaluate through radiographic and microscopic analysis the efficiency of the filling techniques by vertical hidraulic compression after the root canal mechanical instrumentation in vitro as well to evaluate the marginal apical leakage through macroscopic and microscopic analysis. Thirty human mandibular molars were used , they were divided on three groups, these were subdivided on six subgroups with five specimens each, come down to 106 root canals filled. Initially, the teeth were instrumented with Profile system series 29 and filled with two ways: single accessory cone or single cone associated with gutta-percha secundary cone, with Fill Canal sealer or Sealer 26. Completed the filling, the teeth were coated with araldit and finger -nail polish except for the apical 2 mm and dried for 3 hours, thep radiographs were taken of the teeth in orto and disto-radiai directions. Next, the coronal seal was carried out with composite resin photopolymerized and with their process of making impermeable. Teeth of positive controls were used without araldit and finger-nail polish whereas the negative controls were used with total coat of araldit and finger-nail polish. The specimens were placed in 2% Methylene Blue dye for 24 hours and thermocycled for 7 days. Afterwards, sections were made of each tooth at mesial and distal roat, after this the teeth were radiographed at buccolíngual direction for a macroscopic analysis and at buccolingual and mesiodistal directions for assessment of the marginal apical leakage. Cross sections were made 3 mm to 3mm since the tooth apice. The sections obtained for each group were observed with a stereomicroscope to evaluate the quality of the root canal filling and the marginal apical leakage. The results showed that: In the four techniques the marginal dye leakage was present in the apical third; in all groups the quality of the root canal filling in the radiography was better at mesial root canal and the single cone technique showed inefficient when only a single distal root canal was present. In the radiographic evaluation the best quality of the root canal filling was observed in the 1A group (single accessory cone + FiIl Canal), as in the mesial root as in the distal root wich Shcwed twe root canals: when the distaI root had only one canal. the best result was showed by 28 group (single accessory cone associated with secundary cone + Fill Canal) In the macroscopic analysis of longitudinal !eaKage (outside surface). less leakage was showed as In the mesial root as in the distal root in the negative control group (3) followed 2A group (single accessory cone + Sealer 26). When the microscopic analysis of tranversal leakage of both roots (inside surface) was carried out. the groups that showed less dye leakage were the negative control (38) followed the 28 group (single acessory cone associated with secundary cone + Sealer 26). The homogeneity o filling was best noted in the 1 A group (.single accessoty cone + Fill Canal). The groups that showed less dye penetration in the tranversal leakage (total area) were negative control (3B) and 2B

Caracterização macro, meso e microscópica das estruturas frágeis do corpo arenítico conglomerático da região de Santana do Acaraú (CE) e seu embasamento circundante

The structural framework of the sedimentary basins usually plays an important role in oil prospects and reservoirs. Geometry, interconectivity and density of the brittle features developed during basin evolution could change the permo-porous character of the rocks involved in generation, migration and entrapment of fluid flow. Once the structural characterization of the reservois using only sub-surface data is not an easy task, many studies are focused in analogous outcrops trying to understand the main processes by which brittle tectonic is archieved. In the Santana do Acaraú region (Ceará state, NE Brazil) a pack of conglomeratic sandstone (here named CAC) has its geometry controlled mainly by NE trending faults, interpreted as related to reactivation of a precambrian Sobral Pedro II Lineament (LSP-II). Geological mapping of the CAC showed a major NE-SW trending synform developed before its complete lithification during a dextral transpression. This region was then selected to be studied in details in order of constrain the cretaceous deformation and so help the understanding the deformation of the basins along the brazilian equatorial margin. In order to characterize the brittle deformation in different scales, I study some attributes of the fractures and faults such as orientation, density, kinematic, opening, etc., through scanlines in satellite images, outcrops and thin sections. The study of the satellite images showed three main directions of the macrostructures, N-S, NE-SW and E-W. Two of theses features (N-S and E-W) are in aggreement with previous geophysical data. A bimodal pattern of the lineaments in the CAC´s basement rocks has been evidenciated by the NE and NW sets of structures obtained in the meso and microscale data. Besides the main dextral transpression two others later events, developed when the sediments were complety lithified, were recognized in the area. The interplay among theses events is responsible for the compartimentation of the CAC in several blocks along within some structural elements display diferents orientations. Based on the variation in the S0 orientation, the CAC can be subdivided in several domains. Dispite of the variations in orientations of the fractures/faults in the diferents domains, theses features, in the meso and microscopic scale, are concentrated in two sets (based on their trend) in all domains which show similar orientation of the S0 surface. Thus the S0 orientation was used to group the domains in three major sets: i) The first one is that where S0 is E-W oriented: the fractures are oriented mainly NE with the development of a secondary NW trending; ii) S0 trending NE: the fractures are concentrated mainly along the trend NW with a secondary concentration along the NE trend; iii) The third set, where S0 is NS the main fractures are NE and the secondary concentration is NW. Another analized parameter was the fault/fracture length. This attribute was studied in diferent scales trying to detect the upscale relationship. A terrain digital model (TDM) was built with the brittlel elements supperposed. This model enhanced a 3D visualization of the area as well as the spatial distribution of the fault/fractures. Finally, I believe that a better undertanding of the brittle tectonic affecting both CAC and its nearby basement will help the future interpretations of the tectonic envolved in the development of the sedimentary basins of the brazilian equatorial margin and their oil reservoirs and prospects, as for instance the Xaréu field in the Ceará basin, which subsurface data could be correlated with the surface ones

Evolução estrutural e termocronológica meso-cenozóica da Zona de Cisalhamento Portalegre, Nordeste do Brasil

The Portalegre shear zone (ZCPa), which is located in the Rio Grande do Norte and Paraíba states (Northeastern Brazil), is na important right-lateral, northeast-trending lineament formed during the Brazilian Orogenic Cicle). The ZCPa experienced na important brittle reactivation from the Mesozoic until the present. This reactivation led to the formation of the Gangorra, Pau dos Ferros, Coronel João Pessoa, Icozinho and Rio do Peixe basins. The reactivation northern parto f the ZCPa that marks the boundary of the Potiguar Basin is denominated Carnaubais Fault. Several fracture patterns were mapped along the ZCPa. Samples were collected in Neoproterozoic granite outcrops, along the ZCPa. These samples yielded AFT ages from 86±13 to 376±57 Ma, and the mean track length from 10.9±0.8 to 12.9±1.5 mm. Samples from the East block yielded mean ages of 103 Ma, mean track lengtn 12,1mm, and mean altitude 250m, whereas samples from West block yielded mean ages of 150 Ma, which reach 345 Ma and 220 Ma in the Pau dos Ferros and Coronel João Pessoa basins, respectively. Thermal history models were sorted out for each crustal block. Samples from West block recorded a thermal history from Carboniferous Period until the Permiano, when the block experienced gradual uplift until the Cretaceous, when it underwent downfaulting and heating until the Tertiary, and it eventually experienced a rapid uplift movement until recent times. Samples from the East block presented the same cooling and heating events, but at they occurred different times. The East block thermal record started ~140 Ma, when this block experienced cooling until ~75 Ma. Both blocks show a denundacion/erosional history more similar in the Tertiary. The AFT data indicate an important tectonic event ~140 Ma, when the West block experienced downfaulting and the East block experienced uplift. This tectonic process led to the generation of several sedimentary basins in the region, including the Potiguar basin. This tectonic event is also interpreted as a rift process caused by an E-W-trending extension. It the Tertiary, some heating events can be tentatively attributed to the macau volcanic event

EFEITOS DOS MÉTODOS DE ABATE DE BOVINOS NA EFICIÊNCIA da SANGRIA

O objetivo do presente trabalho foi avaliar os efeitos dos métodos de abate de bovinos com insensibilização prévia através de marreta e pistola pneumática de penetração e sem insensibilização, realizada pelo método kasher, na eficiência da sangria. A eficiência da sangria foi avaliada pela determinação da hemoglobina no sangue e na carne. Foram utilizados 240 bovinos sãos, da raça Nelore, abatidos em matadouro-frigorífico sob Serviço de Inspeção Federal, sendo 60 animais abatidos pelo método judaico (kasher), 60 animais insensibilizados através de marreta, 60 animais insensibilizados através de pistola pneumática de penetração e 60 animais insensibilizados através de pistola pneumática de penetração seguida por estimulação elétrica. Foram colhidas amostras de sangue após a sangria dos animais e de carne, na porção torácica do músculo Longus colli, imediatamente após a chegada da carcaça à câmara frigorífica. Os animais abatidos pelo método kasher apresentaram menor teor de hemoglobina residual na carne e melhor eficiência da sangria. A utilização da estimulação elétrica imediatamente após a sangria dos animais atordoados por pistola pneumática, afetou negativamente a eficiência da sangria.

Dinâmica do peso e da condição corporal e eficiência reprodutiva de ovelhas da raça Santa Inês e mestiças Santa Inês-Suffolk submetidas a dois sistemas de alimentação em intervalos entre partos de 8 meses

O trabalho teve como objetivo comparar a eficiência produtiva e reprodutiva de ovelhas em dois sistemas de alimentação. Noventa e oito matrizes da raça Santa Inês e trinta e nove mestiças Suffolk (3/4 Suffolk + 1/4 Santa Inês) foram divididas em dois tratamentos: tratamento 1 (T1) - mantidas em pastagem, com suplementação de silagem de capim elefante na seca invernal, e tratamento 2 (T2) -mantidas em pastagem, com suplementação de silagem de capim elefante na seca invernal e de concentrado três semanas antes e durante a estação de monta, três semanas antes do parto e durante a lactação. Verificou-se diferença (P<0,05) entre peso inicial (PI) (52,5kg e 54,33kg), e peso final (PF) (53,38kg e 55,76kg) para T1 e T2, respectivamente. Houve efeito de genótipo (P<0,05), sendo PI 51,46 kg para a raça Santa Inês (SI) e 55,38kg para as mestiças Santa Inês-Suffolk (SF). Para PF, observou-se 52,36kg para a Santa Inês e 56,78kg na mestiça Santa Inês-Suffolk. O peso pré-parto (PPP) diferiu (P<0,05) apenas entre as estações, tendo sido de 65,23kg na estação reprodutiva I (2 a 4/2002), 58,15kg na estação reprodutiva II (10 a 12/2002) e 59,73kg na estação reprodutiva III (6 a 8/2003). No peso pós-parto (PPART), também ocorreram diferenças (P<0,05) entre a raça Santa Inês (53,59kg) e a mestiça Santa Inês-Suffolk (57,05kg); no peso aos 30 dias de lactação (P30d) a Santa Inês registrou 52,94kg e a mestiça Santa Inês-Suffolk 55,45kg. O peso aos 70 dias (P70d) de lactação foi para a Santa Inês de 50,83kg e de 53,22 kg para a mestiça Santa Inês-Suffolk; e o peso aos 100dias (P100d) de lactação foi de 51,55kg e de 53,61kg para a Santa Inês e para a mestiça Santa Inês-Suffolk, respectivamente. A condição corporal inicial (CCI) foi maior (P<0,05) para o T2 2,47 do que para o T1 2,16. Na condição corporal final (CCF), 2,19 e 2,6, respectivamente para T1 e T2, mas os tratamentos não diferiram na condição corporal pré-parto (CCPP). A CCI 2,4 para a mestiça Santa Inês-Suffolk foi (P<0,05) em relação a Santa Inês 2,22. A CCF da mestiça Santa Inês-Suffolk de 2,49 também foi maior (P<0,05) que da Santa Inês que obteve 2,3, mas não diferiram na CCPP. em relação as três estações reprodutivas, apenas na estação I a CCI 2,55, CCF 2,8 e a CCPP 3,03 foram maiores (P<0,05). Já as estações reprodutivas II= 2,47 e III= 2,1 diferiram somente na CCPP que foi menor na estação III. Na estação I e T1 ambos os genótipos obtiveram 72,5% de fertilidade e o T2 apresentou para as mestiças Santa Inês-Suffolk 77% e para a Santa Inês 88%. Na estação II o T1 obteve para as mestiças Santa Inês-Suffolk 42% e para as Santa Inês 38% e o T2 resultou em 56 e 50% para as mestiças Santa Inês-Suffolk e Santa Inês respectivamente. Na estação III a fertilidade do T1 foi para as mestiças 60% e para as Santa Inês 54% e o T2 87% e 76% para as mestiças e Santa Inês respectivamente. Encontrou-se diferença na prolificidade, entre os tratamentos, sendo na estação I a prolificidade foi de 1,20 e 1,55, na estação II foi 0,90 e 1,03 e na estação III obteve-se 1,11 e 1,14, respectivamente para o T1 e T2. Concluiu-se que a suplementação melhorou o desempenho reprodutivo das ovelhas.

A condição das coxas anteriores, do meso-catepímero e do meso-catepisterno dos Tabanidae (Diptera) e sua possível importância na classificação

The condition of certain neglected structures and their possible importance to the classification of the family Tabanidae are studied. The front coxae are considered as belonging to two types: 1) short and robust; 2) long and slender. The posterior edge of the meso-katepimeron presents two conditions: 1) without projection, 2) with backward projection. Similar conditions are found in the meso-Katepisternum, but with intermediate conditions. These characters are discussed in relation to the system proposed for the family by Mackerras. Conditions 1 and 2 of the former two structures separate, respectively, the Pangoniinae and Scepsidinae from the Chrysopsinae and Tabaninae. Condition 2 of the third structure seems to be developing independently in different groups of Tabaninae, with varying degrees of development.

Synthesis and characterization of a novel series of meso (nitrophenyl) and meso (carboxyphenyl) substituted porphyrins

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Capacidade de absorção de nutrientes e eficiência nutricional do sorgo sacarino

Foi conduzido um experimento em casa de vegetação, utilizando dois cultivares de sorgo sacarino (Brandes e Rio), cultivados em soluções nutritivas completa e diluída. No final do ciclo as plantas foram colhidas, separadas em partes e foram analisadas N, P, K, Ca, Mg, S, Cu, Fe, Mn e Zn. de maneira geral os dois cultivares apresentaram capacidade de absorção de nutrientes semelhantes medida tanto em regime de fornecimento adequado como em soluções nutritivas diluídas, embora as produções de matéria seca total tenham sido diferentes na solução mais diluída. Com relação a produção de colmos verdes, o cultivar Brandes produziu mais em solução completa e menos em soluções diluídas do que o cultivar Rio, mas a produção de matéria seca de colmos do cultivar Rio, em casa de vegetação, sempre foi maior do que o do cultivar Brandes.