974 resultados para Curvas algebraicas


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Produced water is characterized as one of the most common wastes generated during exploration and production of oil. This work aims to develop methodologies based on comparative statistical processes of hydrogeochemical analysis of production zones in order to minimize types of high-cost interventions to perform identification test fluids - TIF. For the study, 27 samples were collected from five different production zones were measured a total of 50 chemical species. After the chemical analysis was applied the statistical data, using the R Statistical Software, version 2.11.1. Statistical analysis was performed in three steps. In the first stage, the objective was to investigate the behavior of chemical species under study in each area of production through the descriptive graphical analysis. The second step was to identify a function that classify production zones from each sample, using discriminant analysis. In the training stage, the rate of correct classification function of discriminant analysis was 85.19%. The next stage of processing of the data used for Principal Component Analysis, by reducing the number of variables obtained from the linear combination of chemical species, try to improve the discriminant function obtained in the second stage and increase the discrimination power of the data, but the result was not satisfactory. In Profile Analysis curves were obtained for each production area, based on the characteristics of the chemical species present in each zone. With this study it was possible to develop a method using hydrochemistry and statistical analysis that can be used to distinguish the water produced in mature fields of oil, so that it is possible to identify the zone of production that is contributing to the excessive elevation of the water volume.

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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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Nearly 3 x 1011 m3 of medium and light oils will remain in reservoirs worldwide after conventional recovery methods have been exhausted and much of this volume would be recovered by Enhanced Oil Recovery (EOR) methods. The in-situ combustion (ISC) is an EOR method in which an oxygen-containing gas is injected into a reservoir where it reacts with the crude oil to create a high-temperature combustion front that is propagated through the reservoir. The High Pressure Air Injection (HPAI) method is a particular denomination of the air injection process applied in light oil reservoirs, for which the combustion reactions are dominant between 150 and 300°C and the generation of flue gas is the main factor to the oil displacement. A simulation model of a homogeneous reservoir was built to study, which was initially undergone to primary production, for 3 years, next by a waterflooding process for 21 more years. At this point, with the mature condition established into the reservoir, three variations of this model were selected, according to the recovery factors (RF) reached, for study the in-situ combustion (HPAI) technique. Next to this, a sensitivity analysis on the RF of characteristic operational parameters of the method was carried out: air injection rate per well, oxygen concentration into the injected gas, patterns of air injection and wells perforations configuration. This analysis, for 10 more years of production time, was performed with assistance of the central composite design. The reservoir behavior and the impacts of chemical reactions parameters and of reservoir particularities on the RF were also evaluated. An economic analysis and a study to maximize the RF of the process were also carried out. The simulation runs were performed in the simulator of thermal processes in reservoirs STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) from CMG (Computer Modelling Group). The results showed the incremental RF were small and the net present value (NPV) is affected by high initial investments to compress the air. It was noticed that the adoption of high oxygen concentration into the injected gas and of the five spot pattern tends to improve the RF, and the wells perforations configuration has more influence with the increase of the oil thickness. Simulated cases relating to the reservoir particularities showed that smaller residual oil saturations to gas lead to greater RF and the presence of heterogeneities results in important variations on the RF and on the production curves

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Increase hydrocarbons production is the main goal of the oilwell industry worldwide. Hydraulic fracturing is often applied to achieve this goal due to a combination of attractive aspects including easiness and low operational costs associated with fast and highly economical response. Conventional fracturing usually involves high-flowing high-pressure pumping of a viscous fluid responsible for opening the fracture in the hydrocarbon producing rock. The thickness of the fracture should be enough to assure the penetration of the particles of a solid proppant into the rock. The proppant is driven into the target formation by a carrier fluid. After pumping, all fluids are filtered through the faces of the fracture and penetrate the rock. The proppant remains in the fracture holding it open and assuring high hydraulic conductivity. The present study proposes a different approach for hydraulic fracturing. Fractures with infinity conductivity are formed and used to further improve the production of highly permeable formations as well as to produce long fractures in naturally fractured formations. Naturally open fractures with infinite conductivity are usually encountered. They can be observed in rock outcrops and core plugs, or noticed by the total loss of circulation during drilling (even with low density fluids), image profiles, pumping tests (Mini-Frac and Mini Fall Off), and injection tests below fracturing pressure, whose flow is higher than expected for radial Darcian ones. Naturally occurring fractures are kept open by randomly shaped and placed supporting points, able to hold the faces of the fracture separate even under typical closing pressures. The approach presented herein generates infinite conductivity canal held open by artificially created parallel supporting areas positioned both horizontally and vertically. The size of these areas is designed to hold the permeable zones open supported by the impermeable areas. The England & Green equation was used to theoretically prove that the fracture can be held open by such artificially created set of horizontal parallel supporting areas. To assess the benefits of fractures characterized by infinite conductivity, an overall comparison with finite conductivity fractures was carried out using a series of parameters including fracture pressure loss and dimensionless conductivity as a function of flow production, FOI folds of increase, flow production and cumulative production as a function of time, and finally plots of net present value and productivity index

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Oil production and exploration techniques have evolved in the last decades in order to increase fluid flows and optimize how the required equipment are used. The base functioning of Electric Submersible Pumping (ESP) lift method is the use of an electric downhole motor to move a centrifugal pump and transport the fluids to the surface. The Electric Submersible Pumping is an option that has been gaining ground among the methods of Artificial Lift due to the ability to handle a large flow of liquid in onshore and offshore environments. The performance of a well equipped with ESP systems is intrinsically related to the centrifugal pump operation. It is the pump that has the function to turn the motor power into Head. In this present work, a computer model to analyze the three-dimensional flow in a centrifugal pump used in Electric Submersible Pumping has been developed. Through the commercial program, ANSYS® CFX®, initially using water as fluid flow, the geometry and simulation parameters have been defined in order to obtain an approximation of what occurs inside the channels of the impeller and diffuser pump in terms of flow. Three different geometry conditions were initially tested to determine which is most suitable to solving the problem. After choosing the most appropriate geometry, three mesh conditions were analyzed and the obtained values were compared to the experimental characteristic curve of Head provided by the manufacturer. The results have approached the experimental curve, the simulation time and the model convergence were satisfactory if it is considered that the studied problem involves numerical analysis. After the tests with water, oil was used in the simulations. The results were compared to a methodology used in the petroleum industry to correct viscosity. In general, for models with water and oil, the results with single-phase fluids were coherent with the experimental curves and, through three-dimensional computer models, they are a preliminary evaluation for the analysis of the two-phase flow inside the channels of centrifugal pump used in ESP systems

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Aiming to reduce and reuse waste oil from oily sludge generated in large volumes by the oil industry, types of nanostructured materials Al-MCM-41 and Al-SBA-15, with ratios of Si / Al = 50, were synthesized , and calcined solids used as catalysts in the degradation of oily sludge thermocatalytic oil from oilfield Canto do Amaro, in the state of Rio Grande do Norte. Samples of nanostructured materials were characterized by thermogravimetric analysis (TG / DTG), X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the infrared Fourier transform (FT-IR) and adsorption nitrogen (BET). The characterization showed that the synthesized materials resulted in a catalyst nanostructure, and ordered pore diameter and surface area according to existing literature. The oily sludge sample was characterized by determining the API gravity and sulfur content and SARA analysis (saturates, aromatics, resins and asphaltenes). The results showed a material equivalent to the average oil with API gravity of 26.1, a low sulfur content and considerable amount of resins and asphaltenes, presented above in the literature. The thermal and catalytic degradation of the oily sludge oil was performed from room temperature to 870 ° C in the ratios of heating of 5, 10 and 20 ° C min-1. The curves generated by TG / DTG showed a more accelerated degradation of oily sludge when it introduced the nanostructured materials. These results were confirmed by activation energy calculated by the method of Flynn-Wall, in the presence of catalysts reduced energy, in particular in the range of cracking, showing the process efficiency, mainly for extraction of lightweight materials of composition of oily sludge, such as diesel and gasoline

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Petroleum evaluation is analyze it using different methodologies, following international standards to know their chemical and physicochemical properties, contaminant levels, composition and especially their ability to generate derivatives. Many of these analyzes consuming a lot of time, large amount of samples , supplies and need an organized transportation logistics, schedule and professionals involved. Looking for alternatives that optimize the evaluation and enable the use of new technologies, seven samples of different centrifuged Brazilian oils previously characterized by Petrobras were analyzed by thermogravimetry in 25-900° C range using heating rates of 05, 10 and 20ºC per minute. With experimental data obtained, characterizations correlations were performed and provided: generation of true boiling point curves (TBP) simulated; comparing fractions generated with appropriate cut standard in temperature ranges; an approach to obtain Watson characterization factor; and compare micro carbon residue formed. The results showed a good chance of reproducing simulated TBP curve from thermogravimetry taking into account the composition, density and other oil properties. Proposed correlations for experimental characterization factor and carbon residue followed Petrobras characterizations, showing that thermogravimetry can be used as a tool on oil evaluation, because your quick analysis, accuracy, and requires a minimum number of samples and consumables

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The aging process if characterizes for a complex events network, from multidimensional nature, that encloses biological, social, psychic and functional aspects. The alteration of one or more aspects can speed up the aging process, anticipating limitations and until the death in the aged. For an adjusted confrontation of this question is necessary an interdisciplinary vision, in which the some areas of the knowledge can interact and with this to intervenes of the best possible form. Then, information derived from studies of aspects related to incidence, morbidity-mortality and transition patterns, involved in the health-illness process can more accurately identify risk groups thereby establishing links between social factors, illness, incapacity and death. Thus, this study aimed to identify, by a multidimensional vision, the risk factors of mortality in a coorth of elderly in a city in the interior of the state of Rio Grande do Norte (RN), Brazil. A prospective study carried out in Santa Cruz RN, where 310 elderly were randomly selected to form a baseline. The follow-up was 53 months. The predictive variables were divided into sociodemographic, physical health, neuropsychiatric and functional capacity. The statistical analysis carried out by bivariate analysis, survival analysis, followed by binary logistic regression and Cox regression, in the multivariate analysis, considering significant levels p < 0.05 and confidence interval (CI) of 95%. A total of 60 (19.3%) elderly died during the follow-up, where cardiovascular disease was the main cause. The survival was approximately 24.8 months. The study of general survival showed, at 12, 24, 36, and 48 months of observation, a survival rate of 97%, 54%, 31%, and 5% respectively, with a statistical difference in survival only observed for the variables of cognitive function and Basic Activities of Daily Living. In the logistic regression analysis, the risk factors identified were cognitive deficits (OR = 8.74), poor perception of health (OR = 3.89) and dependence for Basic Activities of Daily Living (OR = 3.96). In the Cox analysis, as well as dependence for Basic Activities of Daily Living (HR = 3.17), cognitive deficit (HR = 4.30) and stroke (CVA) (HR = 3.49) continued as independent risk factors for death. The risk factors found in the study can be interpreted as the primary predictors for death among elderly members of the community. Therefore, improvements in health conditions, with actions towards sustaining an autonomous life with special attention for elderly with cognitive impairment, could mean additional healthy quality of life, resulting in the reduction of premature mortality in this population

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Introduction: Mouth cancer is classified as having one of the ten highest cancer incidences in the world. In Brazil, the incidence and mortality rates of oral cancer are among the highest in the world. Intraoral cancer (tongue, gum, floor of the mouth, and other non-specified parts of the mouth), the accumulated survival rate after five years is less than 50%. Objectives: Estimate the accumulated survival probability after five years and adjust the Cox regression model for mouth and oropharyngeal cancers, according to age range, sex, morphology, and location, for the city of Natal. Describe the mortality and incidence coefficients of oral and oropharyngeal cancer and their tendencies in the city of Natal, between 1980 and 2001 and between 1997 and 2001, respectively. Methods: Survival data of patients registered between 1997 and 2001 was obtained from the Population-based Cancer Record of Natal. Differences between the survival curves were tested using the log-rank test. The Cox proportional risk model was used to estimate risk ratios. The simple linear regression model was used for tendency analyses of the mortality and incidence coefficients. Results: The probability after five years was 22.9%. The patients with undifferentiated malignant neoplasia were 4.7 times more at risk of dying than those with epidermoid carcinoma, whereas the patients with oropharyngeal cancer had 2.0 times more at risk of dying than those with mouth cancer. The mouth cancer mortality and incidence coefficients for Natal were 4.3 and 2.9 per 100 000 inhabitants, respectively. The oropharyngeal cancer mortality and incidence coefficients were, respectively, 1.1 and 0.7 per 100 000 87 inhabitants. Conclusions: A low survival rate after five years was identified. Patients with oropharyngeal cancer had a greater risk of dying, independent of the factors considered in this study. Also independent of other factors, undifferentiated malignant neoplasia posed a greater risk of death. The magnitudes of the incidence coefficients found are not considered elevated, whereas the magnitudes of the mortality coefficients are high

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Conselho Nacional de Desenvolvimento Científico e Tecnológico

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Investigations in the field of pharmaceutical analysis and quality control of medicines require analytical procedures with good perfomance characteristics. Calibration is one of the most important steps in chemical analysis, presenting direct relation to parameters such as linearity. This work consisted in the development of a new methodology to obtain calibration curves for drug analysis: the stationary cuvette one. It was compared to the currently used methodology, and possible sources of variation between them were evaluated. The results demonstrated that the proposed technique presented similar reproducibility compared to the traditional methodology. In addition to that, some advantages were observed, such as user-friendliness, cost-effectiveness, accuracy, precision and robustness. Therefore, the stationary cuvette methodology may be considered the best choice to obtain calibration curves for drug analyis by spectrophotometry

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According to the global framework regarding new cases of tuberculosis, Brazil appears at the 18th place. Thus, the Ministry of Health has defined this disease as a priority in the governmental policies. As a consequence, studies concerning treatment and prevention have increased. Fixed-dose combination formulations (FDC) are recognized as beneficial and are recommended by WHO, but they present instability and loss on rifampicin bioavailability. The main purpose of this work was to carry out a pre-formulation study with the schedule 1 tuberculosis treatment drugs: rifampicin, isoniazid, pyrazinamide and ethambutol and pharmaceutical excipients (lactose, cellulose, magnesium stearate and talc), in order to develop an FDC product (150 mg of rifampicin + 75 mg of isoniazid + 400 mg of pyrazinamide + 250 mg of ethambutol). The studies consisted of the determination of particle size and distribution (Ferret s diameter) and shape through optical microscopy, as well as rheological and technological properties (bulk and tapped densities, Hausner Factor, Carr s Index, repose angle and flux rate) and interactions among drugs and drug excipient through thermal analysis (DSC, DTA, TG and your derivate). The results showed that, except isoniazid, the other drugs presented poor rheological properties, determined by the physical characteristics of the particles: small size and rod like particles shape for rifampicin; rectangular shape for pyrazinamide and ethambutol, beyond its low density. The 4 drug mixture also not presented flowability, particularly that one containing drug quantity indicated for the formulation of FDC products. In this mixture, isoniazid, that has the best flowability, was added in a lower concentration. The addition of microcrystalline cellulose, magnesium stearate and talc to the drug mixtures improved flowability properties. In DSC analysis probable interactions among drugs were found, supporting the hypothesis of ethambutol and pyrazinamide catalysis of the rifampicin-isoniazid reaction resulting in 3- formylrifamycin isonicotinyl hydrazone (HYD) as a degradation product. In the mixtures containing lactose Supertab® DSC curves evidenced incompatibility among drugs and excipient. In the DSC curves of mixtures containing cellulose MC101®, magnesium stearate and talc, no alterations were observed comparing to the drug profiles. The TG/DTG of the binary and ternary mixtures curves showed different thermogravimetrics profiles relating that observed to the drug isolated, with the thermal decomposition early supporting the evidences of incompatibilities showed in the DSC and DTA curves

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Bioidentical hormones are defined as compounds that have exactly the same chemical and molecular structure as hormones that are produced in the human body. It is believed that the use of hormones may be safer and more effective than the non-bioidentical hormones, because binding to receptors in the organism would be similar to the endogenous hormone. Bioidentical estrogens have been used in menopausal women, as an alternative to traditional hormone replacement therapy. Thermal data of these hormones are scarce in literature. Thermal analysis comprises a group of techniques that allows evaluating the physical-chemistry properties of a drug, while the drug is subjected to a controlled temperature programming. The thermal techniques are used in pharmaceutical studies for characterization of drugs, purity determination, polymorphism identification, compatibility and evaluation of stability. This study aims to characterize the bioidentical hormones estradiol and estriol through thermal techniques TG/DTG, DTA, DSC, DSC-photovisual. By the TG curves analysis was possible to calculated kinetic parameters for the samples. The kinetic data showed that there is good correlation in the different models used. For both estradiol and estriol, was found zero order reaction, which enabled the construction of the vapor pressure curves. Data from DTA and DSC curves of melting point and purity are the same of literature, showed relation with DSC-photovisual results. The analysis DTA curves showed the fusion event had the best linearity for both hormones. In the evaluation of possible degradation products, the analysis of the infrared shows no degradation products in the solid state

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Retinoic acid (RA) and hydroquinone (HQ) assets are widely used in pharmaceutical and cosmetic formulations, for having depigmenting properties and are largely produced in drugstores. To assist in the development of formulations containing the active RA and HQ National Forms of Brazilian Pharmacopoeia (2005 and 2012 ) proposes formulations with different excipients such as cetyl alcohol (AC), cetostearyl alcohol (ACT), methylparaben (MTP), propyl paraben ( PPB), glycerin (GLY), dipropylene glycol (DPG), imidazolidinil urea ( IMD ), cyclomethicone (CCM ), butylated hydroxytoluene (BHT), octyl stearate (ETO), EDTA, decil oleate (ODC) and hydroxipropymethyl celullose (HPMC). One of the difficulties found in most cosmetic formulations is the large number of incompatibilities between the components of the formulations, so the aim this study was to evaluate thermal stability and interactions between these active pharmaceutical ingredients and excipients. The depigmenting agents were analyzed by DSC and TG and excipients were analyzed by TG. The dynamic thermogravimetric curves were obtained on a SHIMADZU thermobalance, model DTG-60, using an alumina crucible, at the heating rate of 10ºC min-1, in the temperature range of 25-900 ºC, under an atmosphere of nitrogen at 50 mL min-1. The DSC curves were obtained using Shimadzu calorimeter, model DSC-60, using aluminum crucible, at the heating rate of 10ºC min-1, in the temperature range of 25-400ºC. The thermogravimetric and calorimetric curves were analyzed using TASYS software SHIMADZU. In this study no were found interactions between AR and the following excipients: MTP, PPB, IMD, ODC, EDTA, CCM, ETO, HPMC. However, were found interactions with the following excipients: AC, ACT, BHT, GLI and DPG. For HQ were found interactions with IMD and DPG. Interactions remained even changing proportions of the mixtures and the ternary. Thus, the studies conducted with excipients of National Formulary from 2005 and 2012 showed that these new excipients do not interact by thermogravimetry with the active pharmaceutical ingredients of this study