Obtenção de polímeros graftizados de quitosana e estudo das propriedades físico-químicas para aplicação na indústria do petróleo

Chitosan is a biopolymer derived from the shells of crustaceans, biodegradable, inexpensive and renewable with important physical and chemical properties. Moreover, the different modifications possible in its chemical structure generate new properties, making it an attractive polysaccharide owing to its range of potential applications. Polymers have been used in oil production operations. However, growing concern over environmental constraints has prompted oil industry to search for environmentally sustainable materials. As such, this study sought to obtain chitosan derivatives grafted with hydrophilic (poly(ethylene glycol), mPEG) and/or hydrophobic groups (n-dodecyl) via a simple (one-pot) method and evaluate their physicochemical properties as a function of varying pH using rheology, small-angle Xray scattering (SAXS), dynamic light scattering (DLS) and zeta potential. The chitosan derivatives were prepared using reductive alkylation under mild reaction conditions and the chemical structure of the polymers was characterized by nuclear magnetic resonance (1H NMR) and CHN elemental analysis. Considering a constant mPEG/Chitosan molar ratio on modification of chitosan, the solubility of the polymer across a wide pH range (acidic, neutral and basic) could only be improved when some of the amino groups were submitted to reacetylation using the one-pot method. Under these conditions, solubility is maintained even with the simultaneous insertion of n-dodecyl. On the other hand, the solubility of derivatives obtained only through mPEG incorporation using the traditional methodology, or with the ndodecyl group, was similar to that of its precursor. The hydrophilic group promoted decreased viscosity of the polymer solutions at 10 g/L in acid medium. However, at basic pH, both viscosity and thermal stability increased, as well as exhibited a pronounced pseudoplastic behavior, suggesting strong intermolecular associations in the alkaline medium. The SAXS results showed a polyelectrolyte behavior with the decrease in pH for the polymer systems. DLS analyses revealed that although the dilute polymer solutions at 1 g/L and pH 3 exhibited a high density of protonated amino groups along the polymer chain, the high degree of charge contributed significantly to aggregation, promoting increased particle size with the decrease in pH. Furthermore, the hydrophobic group also contributed to increasing the size of aggregates in solution at pH 3, whereas the hydrophilic group helped reduce their size across the entire pH range. Nevertheless, the nature of aggregation was dependent on the pH of the medium. Zeta potential results indicated that its values do not depend solely on the surface charge of the particle, but are also dependent on the net charge of the medium. In this study, water soluble associative polymers exhibit properties that can be of great interest in the petroleum industry

Interações entre a carboximetilcelulose, carbonato de cálcio e bentonita: repercussões sobre as propriedades dos fluidos de perfuração aquosos

The role of carboxymethylcellulose (CMC) in association to calcium carbonate particles (CaCO3) in most water-based drilling fluids is to reduce the fluid loss to the surrounding formation. Another essential function is to provide rheological properties capable of maintaining in suspension the cuttings during drilling operation. Therefore, it is absolutely essential to correlate the polymer chemical structure (degree of substitution, molecular weight and distribution of substituent) with the physical-chemical properties of CaCO3, in order to obtain the better result at lower cost. Another important aspect refers to the clay hydration inhibitive properties of carboxymethylcellulose (CMC) in drilling fluids systems. The clay swelling promotes an undesirable damage that reduces the formation permeability and causes serious problems during the drilling operation. In this context, this thesis consists of two main parts. The first part refers to understanding of interactions CMC-CaCO3, as well as the corresponding effects on the fluid properties. The second part is related to understanding of mechanisms by which CMC adsorption occurs onto the clay surface, where, certainly, polymer chemical structure, ionic strength, molecular weight and its solvency in the medium are responsible to affect intrinsically the clay layers stabilization. Three samples of carboximetilcellulose with different molecular weight and degree of substitution (CMC A (9 x 104 gmol DS 0.7), CMC B (2.5 x 105 gmol DS 0.7) e CMC C (2.5 x 105 gmol DS 1.2)) and three samples of calcite with different average particle diameter and particle size distribution were used. The increase of CMC degree of substitution contributed to increase of polymer charge density and therefore, reduced its stability in brine, promoting the aggregation with the increase of filtrate volume. On the other hand, the increase of molecular weight promoted an increase of rheological properties with reduction of filtrate volume. Both effects are directly associated to hydrodynamic volume of polymer molecule in the medium. The granulometry of CaCO3 particles influenced not only the rheological properties, due to adsorption of polymers, but also the filtration properties. It was observed that the lower filtrate volume was obtained by using a CaCO3 sample of a low average size particle with wide dispersion in size. With regards to inhibition of clay swelling, the CMC performance was compared to other products often used (sodium chloride (NaCl), potassium chloride (KCl) and quaternary amine-based commercial inhibitor). The low molecular weight CMC (9 x 104 g/mol) showed slightly lower swelling degree compared to the high molecular weight (2.5 x 105 g/mol) along to 180 minutes. In parallel, it can be visualized by Scanning Electron Microscopy (SEM) that the high molecular weight CMC (2.5 x 105 g/mol e DS 0.7) promoted a reduction in pores formation and size of clay compared to low molecular weight CMC (9.0 x 104 g/mol e DS 0.7), after 1000 minutes in aqueous medium. This behavior was attributed to dynamic of interactions between clay and the hydrodynamic volume of CMC along the time, which is result of strong contribution of electrostatic interactions and hydrogen bounds between carboxylate groups and hydroxyls located along the polymer backbone and ionic and polar groups of clay surface. CMC adsorbs on clay surface promoting the skin formation , which is responsible to minimize the migration of water to porous medium. With the increase of degree of substitution, it was observed an increase of pores onto clay, suggesting that the higher charge density on polymer is responsible to decrease its flexibility and adsorption onto clay surface. The joint evaluation of these results indicate that high molecular weight is responsible to better results on control of rheological, filtration and clay swelling properties, however, the contrary effect is observed with the increase of degree of substitution. On its turn, the calcite presents better results of rheological and filtration properties with the decrease of average viii particle diameter and increase of particle size distribution. According to all properties evaluated, it has been obvious the interaction of CMC with the minerals (CaCO3 and clay) in the aqueous medium

Obtenção de dispersões de complexos polieletrolíticos à base de quitosana e poli(ácido metacrílico) e análise de adsorção de albumina bovina sérica

Dispersions composed of polyelectrolyte complexes based on chitosan and poly(methacrylic acid), PMAA, were obtained by the dropping method and template polymerization. The effect of molecular weight of PMAA and ionic strength on the formation of chitosan/poly(methacrylic acid), CS/PMAA, complexes was evaluated using the dropping method. The increase in molecular weight of PMAA inhibited the formation of insoluble complexes, while the increase in ionic strength first favored the formation of the complex followed by inhibiting it at higher concentrations. The polyelectrolyte complexation was strongly dependent on macromolecular dimensions, both in terms of molecular weight and of coil expansion/contraction driven by polyelectrolyte effect. The resultant particles from dropping method and template polymerization were characterized as having regions with different charge densities: chitosan predominating in the core and poly(methacrylic acid) at the surface, the particles being negatively charged, as a consequence. Albumin was adsorbed on templatepolymerized CS/PMAA complexes (after crosslinking with glutardialdehyde) and pH was controlled in order to obtain two conditions: (i) adsorption of positively charged albumin, and (ii) adsorption of albumin at its isoelectric point. Adsorption isotherms and zeta potential measurements showed that albumin adsorption was controlled by hydrogen bonding/van der Waals interactions and that brushlike structures may enhance adsorption of albumin on these particles

Estudo in silico das interações da protease NS3-NS2B de DENV-2 com o inibidor peptídico Bz-nKRR-H com finalidades terapêuticas

Dengue virus is an important patogen that causes Dengue desease in all world, and belongs to Flavivirus gender. The virus consists of enveloped RNA with a single strand positive sense, 11Kb genome. The RNA is translated into a polyprotein precursor, wich is cleaved into 3 structural proteins (C, prM e E) and 7 non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B e NS5). The NS3 is a multifunctional protein, that besides to promote the polyprotein precursor cleavage, also have NTPase, helicase and RTPase activity. The NS3 needs a hydrophilic segment of 40 residues from the transmembrane NS2B protein (who acts like cofator) to realize this functions. Actually, there's no vacines available on the market, and the treatment are just symptomatic. The tetrapeptide inhibitor Bz-Nle-Lys-Arg-Arg-H (Ki de 5,8-7,0 M) was showed as a potent inhibitor μ for NS3prot in Dengue virus. That is a inteligent alternative to treat the dengue desease. The present work aimed analyse the interactions of the ligand bounded to the activity site to provid a clear and depth vision of that interaction. For this purpouse, it was conducted an in silico study, by using quantum mechanical calculations based on Density Functional Theory (DFT), with Generalized Gradient approximation (GGA) to describe the effects of exchange and correlation. The interaction energy of each amino acid belonging to the binding site to the ligand was calculated the using the method of molecular fragmentation with conjugated caps (MFCC). Besides energy, we calculated the distances, types of molecular interactions and atomic groups involved. The theoretical models used were satisfactory and show a more accurate description when the dielectric constant = 20 ε and 80 was used. The results demonstrate that the interaction energy of the system reached convergence at 13.5 A. Within a radius of 13,5A the most important residues were identified. Met49, Met84 and Asp81 perform interactions of hydrogen with the ligant. The Asp79 and Asp75 residues present high energy of attraction. Arg54, Arg85 and Lys 131 perform hydrogen interactions with the ligand, however, appear in BIRD graph having high repulsion energy with the inhibitor. The data also emphasizes the importance of residue Tyr161 and the involvement of the catalytic triad composed by Asp75, His51 and Ser135

Redução in situ de NIO durante a sinterização de misturas NI/NIO produzidas por metalurgia do pó

The nickel alloys are widely used in the production of various materials, especially those that require mechanical strength characteristics associated with resistance to corrosion, for example, the stainless steel. Another use is the production of nickel alloy sintered from powder of metallic nickel. A promising alternative for the production of sintered components of nickel with an important reduction in costs of starting material is the use of mixtures of powders of Ni-NiO. This work aimed to study in situ reduction of NiO during sintering mixtures of Ni / NiO produced by powder metallurgy. The nickel mixtures have been processed by the technique of powder metallurgy and were pre-sintered in an oven under plasma reducing atmosphere of hydrogen. Mixtures Ni +15%NiO, Ni +25%NiO and Ni +35%NiO were studied and compared with samples consisting only of metallic Ni. Dilatometric tests were performed to study the sintering conditions of the mixtures. The consolidated material was analyzed for their microstructure and microhardness. Dilatometry graphs showed that the addition of nickel oxide in all compositions the active sintering the mixtures studied. In tests of microhardness indentations were made at different points of the sample surface. All compositions showed microhardness values close to the consolidated material from metallic nickel. However, sample containing Ni+35% NiO, showed a large dispersion of the values of microhardness tests performed at different points of the sample surface. Microstructural analysis of the material showed a higher concentration of voids and the presence of oxides in the waste composition of the mixtures Ni 35% NiO. The samples containing Ni+15%NiO showed microstructural characteristics and mechanical properties similar to metallic nickel consolidated under the same conditions of the compositions studied in this work and therefore had great potential for production of sintered nickel alloys

Efeito da moagem de alta energia na densificação e microestrutura do compósito AI2O3-Cu

The Cu-Al2O3 composite ceramic combines the phase of alumina, which is extremely hard and durable, yet very brittle, to metallic copper phase high ductility and high fracture toughness. These characteristics make this material a strong candidate for use as a cutting tool. Al2O3-Cu composite powders nanocrystalline and high homogeneity can be produced by high energy milling, as well as dense and better mechanical structures can be obtained by liquid phase sintering. This work investigates the effect of high-energy milling the dispersion phase Al2O3, Cu, and the influence of the content of Cu in the formation of Cu-Al2O3 composite particles. A planetary mill Pulverisatte 7 high energy was used to perform the experiments grinding. Al2O3 powder and Cu in the proportion of 5, 10 and 15% by weight of Cu were placed in a container for grinding with balls of hard metal and ethyl alcohol. A mass ratio of balls to powder of 1:5 was used. All powders were milled to 100 hours, and powder samples were collected after 2, 10, 20, 50 and 70 hours of grinding. Composite powders with compact cylindrical shape of 8 mm diameter were pressed and sintered in uniaxial matrix resistive furnace to 1200, 1300 to 1350 °C for 60 minutes under an atmosphere of argon and hydrogen. The heating rate used was 10°C/min. The powders and structures of the sintered bodies were characterized by XRD, SEM and EDS. Analysis TG, DSC and particle size were also used to characterize the milled powders, as well as dilatometry was used to observe the contraction of the sintered bodies. The density of the green and sintered bodies was measured using the geometric method (mass / volume). Vickers microhardness with a load of 500 g for 10 s were performed on sintered structures. The Cu-Al2O3 composite with 5% copper density reached 61% of theoretical density and a hardness of 129 HV when sintered at 1300 ° C for 1h. In contrast, lower densities (59 and 51% of the theoretical density) and hardness (110 HV and 105) were achieved when the copper content increases to 10 and 15%.

Obtenção de Mo2C com adição de Co por reação gás-sólido em reator de leito fixo

Sulfur compounds emissions have been, on the late years, subject to more severe environmental laws due to its impact on the environment (causing the acid rain phenomena) and on human health. It has also been object of much attention from the refiners worldwide due to its relationship with equipment’s life, which is decreased by corrosion, and also with products’ quality, as the later may have its color, smell and stability altered by the presence of such compounds. Sulfur removal can be carried out by hydrotreating (HDT) which is a catalytic process. Catalysts for HDS are traditionally based on Co(Ni)-Mo(W)/Al2O3. However, in face of the increased contaminants’ content on crude oil, and stricter legislation on emissions, the development of new, more active and efficient catalysts is pressing. Carbides of refractory material have been identified as potential materials for this use. The addition of a second metal to carbides may enhance catalytic activities by increasing the density of active sites. In the present thesis Mo2C with Co addition was produced in a fixed bed reactor via gas-solid reaction of CH4 (5%) and H2(95%) with a precursor made of a mix of ammonium heptamolybdate [(NH4)6[Mo7O24].4H2O] and cobalt nitrate[Co(NO3)2.6H2O] at stoichiometric amounts. Precursors’ where analyzed by XRF, XRD, SEM and TG/DTA. Carboreduction reactions were carried out at 700 and 750°C with two cobalt compositions (2,5 and 5%). Reaction’s products were characterized by XRF, XRD, SEM, TOC, BET and laser granulometry. It was possible to obtain Mo2C with 2,5 and 5% cobalt addition as a single phase at 750°C with nanoscale crystallite sizes. At 700°C, however, both MoO2 and Mo2C phases were found by XRD. No Co containing phases were found by XRD. XRF, however, confirmed the intended Co content added. SEM images confirmed XRD data. The increase on Co content promoted a more severe agglomeration of the produced powder. The same effect was noted when the reaction temperature was increased. The powder synthesized at 750°C with 2,5% Co addition TOC analysis indicated the complete conversion from oxide material to carbide, with a 8,9% free carbon production. The powder produced at this temperature with 5% Co addition was only partially converted (86%)

Síntese e caracterização de compostos de coordenação do Ácido 4-cloro-2-(2- furilmetilamino)-5- sulfamoil-benzóico com os íons níquel, cobalto e zinco

This work aimed to promote the synthesis, characterization and propose a plausible molecular structure for coordination compounds involving furosemide (4-Chloro-2-(2- furylmethylamino)-5-sulfamoyl-benzoic acid) with the metal ions Ni+2, Zn+2 and Co+2. The compounds were obtained in methanoic medium by evaporation of the solvent after the synthesis procedure. For characterization of coordination compounds determining the levels of metals by EDTA complexometry, infrared spectroscopy (FTIR), solubility of compounds in various solvents, thermogravimetry (TG), differential scanning calorimetry (DSC), differential thermal analysis were made (DTA), determination of the carbon , hydrogen and nitrogen (CHN). The results of infrared spectroscopy in the region suggest that the organic ligand is coordinated in a bidentate fashion to the metal ions, the metal center interactions to occur by the coordination of the nitrogen atom of the amino group and the oxygen atom of the carboxylic acid of the structure of furosemide. With the results of the levels of metal, elemental analysis (CHN) and thermal analysis has been possible to propose the structure of the ligand. The values of the molar conductivity of the complex in acetonitrile behavior suggest the non acetonitrile electrolyte solution. With the solubility tests it was found that the compounds have high solubility in methanol and acetonitrile, as are partially insoluble in water. From the results of thermal analysis (TG, DSC, DTA), it was possible to obtain the thermal behavior of the compounds as stages of dehydration, thermal stability, decomposition and the energies involved.

Bioquímica quântica na diferenciação dos níveis de ativação de receptores AMPA por agonistas parciais Wilardina

In the central nervous system (CNS) of mammalian, fast synaptic transmission between nerve cells is performed primarily by α-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid (AMPA) receptors, an ionotropic glutamate receptor that is related with learning, memory and homeostasis of the nervous system. Impairments in their functions are correlated with development of many brain desorders, such as epilepsy, schizophrenia, autism, Parkinson and Alzheimer. The use of willardiine analogs has been shown a powerful tool to understanding of activation and desensitization mechanisms of this receptors, because the modification of a single ligand atom allows the observation of varying levels of efficacy. In this work, taking advantage of Fluorine Willardiine (1.35Å), Hydrogen Willardiine (1.65Å), Bromine Willardiine (1.8Å) and Iodine Willardiine (2.15Å) structures co-crystalized with GluA2 with codes 1MQI, 1MQJ, 1MQH and 1MQG, we attempted to energetically differentiate the four ligands efficacy. The complexes were submitted to energetic calculations based on density functional theory (DFT), under the optics of molecular fractionation with conjugate caps (MFCC) method. Obtained results show a relationship between the energetic values and willardiines efficacy order (FW> HW > BrW > IW), also show the importance of E705, R485, Y450, S654, T655, T480 e P478 as the amino acids that contribute most strongly with the interaction of four partial agonists. Furthermore, we outlined the M708 behaviour, attracted by FW and HW ligands, and repels by BrW and IW. With the datas reported on this work, it is possible for a better understanding of the AMPA receptor, which can serve as an aid in the development of new drugs for this system.

Síntese de carreadores de oxigênio à base de Ni e Co para estudo do processo de Chemical Looping usando CH4 como combustível

Increasing energy demand is being met largely by fossil fuel reserves, which emit CO2, SOx gases and various other pollutants. So does the search for fuels that emit fewer pollutants and have the same energy efficiency. In this context, hydrogen (H2) has been increasingly recognized as a potential carrier of energy for the near future. This is because the H2 can be obtained by different routes and has a wide application area , in addition to having clean burning, generating only H2O as a product of combustion , and higher energy density per unit mass . The Chemical Looping Reforming process (CLR) has been extensively investigated in recent years, it is possible to regenerate the catalyst by applying cycles of reduction and oxidation. This work has as main objective to develop catalysts based on nickel and cobalt to study the reactivity of reform with chemical recycling process. The catalysts were prepared by three different methods: combustion assisted by microwave, wet impregnation and co-precipitation. All catalysts synthesized have the same amount by weight of the active phases (60% w / w). The other 40 % m/m consists in La2O3 (8% w / w), Al2O3 (30% w / w) and MgO (2%). Oxygen carriers have been named as follows: N or C, nickel or cobalt, followed by the number 3 or 6, meaning 30 to 60% of active phase in the oxide form and C, CI or CP, which means self-combustion assisted by microwave, self-combustion assisted by microwave followed by wet impregnation and co-precipitation. The oxygen carriers were then characterized by the techniques of X-ray diffraction (XRD), surface area (BET), temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The characterization results showed that the different synthesis methods have led to obtaining different morphologies and structures. Redox tests using CH4 as reducing agent and sintetic air as oxidant agent was done with N6C and C6C, N6CI and C6CI and N6CP and C6CP oxygen carriers. The tests revealed different behaviors, depending on active phase and on synthesis procedure. N6C oxygen carrier produced high levels of H2. The C6CI oxygen carrier produced CO2 and H2O without carbon deposits.

Análise experimental de danos em pistões de motor à gasolina operando com adição de gás hidróxi

The addition of hydrogen gas as an alternative fuel source has been widely used, as well reported in scientific literature. Today, several experiments are underway for the use of hydrogen generators (electrolysers) demand for motor vehicles. In all these products their ads manufacturers claim that this provides a reduction of fuel consumption, reduces the emission levels of toxic gas by the discharge and improves engine life. This research analyzes the physical structure of engine components using electrolysis on demand. To this end, a stationary system was fitted with a power generator of electricity, drum roller and adapted two electrolyzers: a dry cell and wet cell other. In steps observation were consumption analyzes in four work load ranges and observing the piston engine, which has been cut and analyzed by Optical Microscopy (OM), Scanning Electron Microscopy and Dispersive Energy (SEM-EDS), X – Ray Diffraction (XRD) and Confocal Microscopy, the stationary system in each step. The results showed a considerable reduction in fuel consumption and a high corrosion in the original factory piston constituted of aluminum-silicon alloy. As corrosion barrier was made a plasma nitriding in the piston head, which proved resistant to attack by hydrogen, although it has presented evidence also, of having been attacked. It is concluded that the automotive electrolysers can be a good choice in terms of consumption and reducing toxic gas emissions, but the material of the combustion chambers of vehicles must be prepared for this purpose.

Desenvolvimento de material BaCexPr1-xO3 (0 ≤ X ≤ 1) com estrutura perovskita para oxidação catalítica do CO a CO2 em reator de leito fixo

Barium Cerate (BaCeO3) is perovskite type structure of ABO3, wherein A and B are metal cations. These materials, or doped, have been studied by having characteristics that make them promising for the application in fuel cells solid oxide, hydrogen and oxygen permeation, as catalysts, etc .. However, as the ceramic materials mixed conductivity have been produced by different synthesis methods, some conditions directly influence the final properties, one of the most important doping Site B, which may have direct influence on the crystallite size, which in turn directly influences their catalytic activity. In this study, perovskite-type (BaCexO3) had cerium gradually replaced by praseodymium to obtain ternary type materials BaCexPr1-xO3 and BaPrO3 binaries. These materials were synthesized by EDTA/Citrate complexing method and the material characterized via XRD, SEM and BET for the identification of their structure, morphology and surface area. Moreover were performed on all materials, catalytic test in a fixed bed reactor for the identification of that person responsible for complete conversion of CO to CO2 at low operating temperature, which step can be used as the subsequent production of synthesis gas (CO + H2) from methane oxidation. In the present work the crystalline phase having the orthorhombic structure was obtained for all compositions, with a morphology consisting of agglomerated particles being more pronounced with increasing praseodymium in the crystal structure. The average crystal size was between 100 nm and 142,2 nm. The surface areas were 2,62 m²g-1 for the BaCeO3 composition, 3,03 m²g-1 to BaCe0,5Pr0,5O3 composition and 2,37 m²g-1 to BaPrO3 composition. Regarding the catalytic tests, we can conclude that the optimal flow reactor operation was 50 ml / min and the composition regarding the maximum rate of conversion to the lowest temperature was BaCeO3 to 400° C. Meanwhile, there was found that the partially replaced by praseodymium, cerium, there was a decrease in the catalytic activity of the material.

Síntese e caracterização de nanopartículas magnéticas de Co e Ni com aplicação em magneto hipertermia

Nanoparticles are importante for the study of new phenomena and for the development of new applications. Metallic magnetic nanoparticles like Cobalt and Nickel are important for their applications in nanoscience and nanotechnology. In this work, we report on the synthesis and characterization of Ni and Co nanoparticles. The nanoparticles were prepared by the modi- ed sol-gel method and were formed in the pore-network of the biopolymer quitosan. The reduction occurred in absence of H2 ux. The metallic particles and their monoxides have a face-centered- cubic structure. The metallic particles sizes ranged from 59 to 77 nm and from 19 to 50 nm for Ni and Co, respectively. Their monoxides chemically passivated the metallic cores, and after several weeks we have not observed further increase in oxidation. The synthesis method was tuned to obtain mainly the ferromagnetic phase. The system behaves like a core/shell structure with a ferromagnetic core and an antiferromagnetic shell. Exchange bias e ect was observed at temperatures below the Néel temperature. Both systems were submitted to an alternated magnetic eld and the heat released by the particles increased the temperature to 140°C in an interval of 5 min. Similar studies in samples dispersed in water increased the temperatures to 40-59°C, these results suggest that these materials are candidates for magnetic hyperthermia.

Análise wavelet da variabilidade do quasar 3C 273

Discovered in 1963, 3C 273 was the second quasar identified and cataloged in the Third Cambridge Catalog for radio sources, and the first one for which emission lines were identified with a hydrogen sequence redshifted. It is the brightest quasar of the celestial sphere, the most studied, analyzed, and with a resulting abundance of data available in a vast literature. The accurate analysis of the deviations of the spectral lines of quasars provides enough information to put in evidence the variation of fundamental constants of nature and similarly the universe expansion rate. The analysis of the variability of the light curves of these bodies, and the consequent accuracy of their periodicity, is of utmost importance as it provides an efficiency of their observations, enables a greater understanding of the physical phenomena, and makes it possible to conduct spectral observations on more accurate dates (when their light curves show pronounced peaks and therefore richer spectra information). In this master’s thesis twenty eight light curves from the quasar 3C 273 are studied, covering all the electromagnetic spectrum wavebands (radio emission to gamma rays), totaling in the analysis of four light curves for each waveband. We have applied the method of Continuous Wavelet Transform using the sixth-order (!0 = 6) Morlet wavelet function, and obtained excellent results in accordance with the literature.

Análise wavelet da variabilidade do quasar 3C 273

Discovered in 1963, 3C 273 was the second quasar identified and cataloged in the Third Cambridge Catalog for radio sources, and the first one for which emission lines were identified with a hydrogen sequence redshifted. It is the brightest quasar of the celestial sphere, the most studied, analyzed, and with a resulting abundance of data available in a vast literature. The accurate analysis of the deviations of the spectral lines of quasars provides enough information to put in evidence the variation of fundamental constants of nature and similarly the universe expansion rate. The analysis of the variability of the light curves of these bodies, and the consequent accuracy of their periodicity, is of utmost importance as it provides an efficiency of their observations, enables a greater understanding of the physical phenomena, and makes it possible to conduct spectral observations on more accurate dates (when their light curves show pronounced peaks and therefore richer spectra information). In this master’s thesis twenty eight light curves from the quasar 3C 273 are studied, covering all the electromagnetic spectrum wavebands (radio emission to gamma rays), totaling in the analysis of four light curves for each waveband. We have applied the method of Continuous Wavelet Transform using the sixth-order (!0 = 6) Morlet wavelet function, and obtained excellent results in accordance with the literature.