Estudo de um sistema de frenagem eletromagn��tica empregando correntes parasitas

This work deals with the analytical, computational and experimental study of phenomena related to the Eddy current induction in low permeability means for embedded electromagnetic braking systems applications. The phenomena of forces generation in opposing to the variation of stationary magnetic flux produced by DC power supplies, set in motion by the application of an external propulsive force are addressed. The study is motivated by search for solving the problem of speed control of PIGs used to verifying and maintaining pipelines, and is led based on the analytical models synthesis, validated by means of computer simulations in Finite Elements environment, provided by engineering support software; and with experimental tests conducted under controlled laboratory conditions. Finally, a damping systems design methodology based on analyzes results conducted throughout the study is presented

Contribui����o ao estudo avan��ado das argamassas de alto desempenho para reparos estruturais

In��meras estruturas de concreto no Brasil e no mundo est��o atingindo o limite de sua vida ��til projetada, completando um ciclo de cinco ou mais d��cadas de uso e opera����o. Al��m das estruturas mais antigas, existem ainda estruturas com reduzido tempo de servi��o, e qualidade discut��vel, que j�� apresentam patologias em estado t��o avan��ado que chegam a comprometer o seu desempenho. Vindo ao encontro dessas necessidades e no sentido de contribuir para o avan��o cient��fico e tecnol��gico do setor, este trabalho apresenta um m��todo para dosagem, preparo e aplica����o de argamassas de alto desempenho para recupera����o de estruturas deterioradas, al��m de sugerir procedimentos para a realiza����o desses reparos, fomentando a cultura das manuten����es preventivas e desmistificando a complexidade atribu��da a tais opera����es. Para tanto, foram realizados ensaios mec��nicos, microestruturais e relacionados �� durabilidade em corpos-de-prova moldados com s��lica ativa e l��tex de estireno-butadieno. Os resultados indicaram que a ado����o desses ingredientes, na composi����o da argamassa de reparo, provocou uma redu����o significativa da permeabilidade total e descontinuidade de poros, assim como promoveu uma melhor integridade dos constituintes da argamassa, traduzindo-se em uma amplia����o, expressiva, das suas capacidades mec��nicas. Quando comparada aos produtos industrializados da constru����o civil, com padr��es similares, proporcionou uma economia da ordem de 85%, que permitiria recuperar, com os mesmos custos, quase cinco vezes mais estruturas comprometidas. Este estudo, de vi��s altamente tecnol��gico, vem oferecer �� constru����o civil uma argamassa polim��rica de alto desempenho, com fun����o reparadora e custo mais acess��vel, que pode ser adotada em canteiros de obras, implementando a����es de natureza sustent��vel e ainda atendendo ��s atuais exig��ncias elencadas pela literatura, relacionadas �� desempenho, vida ��til e durabilidade das estruturas reparadas.

An��lise computacional de imagens de l��minas delgadas na predi����o dos par��metros hidr��ulicos porosidade e condutividade hidr��ulica do aqu��fero Barreiras-RN

The understanding of the occurrence and flow of groundwater in the subsurface is of fundamental importance in the exploitation of water, just like knowledge of all associated hydrogeological context. These factors are primarily controlled by geometry of a certain pore system, given the nature of sedimentary aquifers. Thus, the microstructural characterization, as the interconnectivity of the system, it is essential to know the macro properties porosity and permeability of reservoir rock, in which can be done on a statistical characterization by twodimensional analysis. The latter is being held on a computing platform, using image thin sections of reservoir rock, allowing the prediction of the properties effective porosity and hydraulic conductivity. For Barreiras Aquifer to obtain such parameters derived primarily from the interpretation of tests of aquifers, a practice that usually involves a fairly complex logistics in terms of equipment and personnel required in addition to high cost of operation. Thus, the analysis and digital image processing is presented as an alternative tool for the characterization of hydraulic parameters, showing up as a practical and inexpensive method. This methodology is based on a flowchart work involving sampling, preparation of thin sections and their respective images, segmentation and geometric characterization, three-dimensional reconstruction and flow simulation. In this research, computational image analysis of thin sections of rocks has shown that aquifer storage coefficients ranging from 0,035 to 0,12 with an average of 0,076, while its hydrogeological substrate (associated with the top of the carbonate sequence outcropping not region) presents effective porosities of the order of 2%. For the transport regime, it is evidenced that the methodology presents results below of those found in the bibliographic data relating to hydraulic conductivity, mean values of 1,04 x10-6 m/s, with fluctuations between 2,94 x10-6 m/s and 3,61x10-8 m/s, probably due to the larger scale study and the heterogeneity of the medium studied.

Desenvolvimento e caracteriza����o de nanoemuls��es cosm��ticas contendo extrato de Opuntia ficus-indica L. Mill e avalia����o in vivo da efic��cia hidratante

Nanoemulsions are emulsified systems, characterized for reduced droplet size (50- 500nm), which the main characteristic are kinect stability and thermodynamic instability. These are promising systems on cosmetic area due to their droplet size that provide different advantages when compared to conventional systems, among others, larger surface area and better permeability. The Opuntia ficus-indica (L.) Mill is a plant cultivated on Caatinga Brazilian biome, which has great socioeconomic importance to region. This plant shows carbohydrates utilized for cosmetic industry as moisturizing active in their chemical composition. The aim of study was to develop, characterize, evaluate stability and moisturizing efficacy of cosmetic nanoemulsions added to Opuntia ficus-indica (L.) Mill extract. Nanoemulsions preparation was made using a low energy method. Different nanoemulsions were formulated varying the ratio of oil, water and surfactant phases beyond xanthan gum (0.5% e 1%) and Opuntia ficus-indica (L.) Mill hydroglycolic extract addition on 1% and 3%. Obtained nanoemulsions were submitted to preliminary and accelerated stability tests. The evaluated parameters monitored were: macroscopic aspect, pH value, droplet size, zeta potential and polydispersion index, during 60 days on different temperatures. Stable formulations were submitted to moisturizing efficacy assessment by capacitance and transepidermal water loss methodologies during 5 hours. Stable samples were white and showed homogeneous and fluid aspect, pH value was inside ideal range (4,5-6,0) to topical application and droplet size under 200nm characterizing these system as nanoemulsions. Developed nanoemulsions did not decrease transepidermal water loss, however increased the water content on stratum corneum, highlighting the nanoemulsions containing 0.5% of xanthan gum and 1% of hydroglycolic extract. This work presents cosmetic moisturizing nanoemulsions composed to vegetal raw material from Brazilian Caatinga with potential to be used on cosmetic area.

Avalia����o do controle da diag��nese na qualidade de reservat��rio silicicl��stico do cenomaniano superior da forma����o A��u, sudoeste da bacia potiguar

The distribution of diagenetic alterations in Late Cenomanian siliciclastic reservoirs from Potiguar Basin was influenced by the stratigraphic framework and the depositional system. Seismic sections and geophysical logs of two wells drilled in the SW portion of the mentioned basin above register regional stratigraphic surfaces representing maximum floods related to a transgressive event. The sequential analysis of 80 m of drill core (~450 m deep) recognized nine depositional facies with an upwards granodecrescent standard piling that limits cycles with an erosional conglomeratic base (lag) overlain by intercalations of medium to very fine sandstones showing cross bedding (channel, planar and low angled) and horizontal bedding (plane-parallel , wave and flaser). The top of the cycles is marked by the deposition of pelites and the development of paleosoils and lagoons. The correlation of genetically related facies reveals associations of channel fillings, crevasse, and flood plains deposited in a transgressive system. Detailed descriptions of seventy nine thin sections aided by MEV-EBSD/EDS, DRX and stable isotope analyses in sandstones revealed an arcosian composition and complex textural arrays with abundant smectite fringes continuously covering primary components, mechanically infiltrated cuticles and moldic and intragrain pores. K-feldspar epitaxial overgrowth covers microcline and orthoclase grains before any other phase. Abundant pseudomatrix due to the compactation of mud intraclasts concentrate along the stratification planes, locally replaced by macrocristalline calcite and microcrystalline and framboidal pyrite. Kaolinite (booklets and vermicular), microcrystalline smectite, microcrystalline titanium minerals and pyrite replace the primary components. The intergrain porosity prevails over the moldic, intragrain and contraction porosities. The pores are poorly connected due to the presence of intergranular smectite, k-feldspar overgrowth, infiltrated mud and pseudomatrix. The sandstones were subjected to eodiagenetic conditions next to the surface and shallow burial mesodiagenetic conditions. The diagenetic alterations reduced the porosity and the permeability mainly due to the precipitation of smectite fringes, compactation of mud intraclasts onto the pseudomatrix and cementing by poikilotopic calcite characterizing different reservoir petrofacies. These diagenetic products acted as barriers and detours to the flow of fluids thus reducing the quality of the reservoir.

Petrologia das fraturas associadas a fei����es t��picas de dissolu����o hipog��nica na Forma����o Salitre, Bacia de Irec��, Bahia, Brasil

The recognition of karst reservoirs in carbonate rocks has become increasingly common. However, most karst features are small to be recognized in seismic sections or larger than expected to be investigated with borehole data. One way forward has been the study of analogue outcrops and caves. The present study investigates lithofacies and karst processes, which lead to the generation of the largest system of caves in South America. The study area is located in the Neoproterozoic Una Group in central-eastern Brazil. This province comprises several systems of carbonate caves (Karmann and Sanch��z, 1979), which include the Toca da Boa Vista and Barriguda caves, considered the largest caves in South America (Auler and Smart, 2003). These caves were formed mainly in dolomites of the Salitre Formation, which was deposited in a shallow marine environment in an epicontinental sea (Medeiros and Pereira, 1994). The Salitre Formation in the cave area comprises laminated mud/wakestones, intraclastic grainstones, oncolitic grainstones, oolitic grainstones, microbial laminites, colunar stromatolites, trombolites and fine siliciclastic rocks (marls, shales, and siltites). A thin layer and chert nodules also occur at the top of the carbonate unit. Phosphate deposits are also found. Our preliminary data indicate that folds and associated joints control the main karstification event at the end of the Brasiliano orogeny (740-540 Ma). We recognized five lithofacies in the cave system: (1) Bottom layers of grainstone with cross bedding comprise the main unit affected by speleogenesis, (2) thin grainstone layers with thin siltite layers, (3) microbial laminites layers, (4) layers of columnar stromatolites, and a (5) top layer of siltite. Levels (1) to (3) are affected by intense fracturing, whereas levels (4) and (5) seal the caves and have little fracturing. Chert, calcite and gipsite veins cut across the carbonate units and play a major role in diagenesis. Our preliminary study indicate that hypogenic spelogenesis is the main process of karst development and contributed significantly to the generation of secondary porosity and permeability in the carbonate units.

Aplica����o de nanoemuls��o ��cida em acidifica����o de po��os de petr��leo

A constante busca da ind��stria de petr��leo pelo aumento de produ����o �� um baixo custo operacional faz necess��rio o desenvolvimento de tecnologias que una as duas necessidades. A Acidifica����o de matriz �� um m��todo de estimula����o frequentemente empregado para aumentar produ����o de um po��o de petr��leo com um custo menor se comparado a um fraturamento. O objetivo deste trabalho �� estudar a obten����o de nanoemuls��es ��cidas para aplica����o em acidifica����o de matriz. As nanoemuls��es s��o capazes de retardar rea����es, por diminuir a difus��o do ��cido no meio, possibilitando a acidifica����o em reservat��rios com baixa permeabilidade. Os reagentes utilizados para formar os sistemas nanoemulsionados foram UNT L90/OMS e RNX 110 como tensoativos, Sec-butanol como cotensoativo, Xileno e Querosene como fase ��leo e Solu����o de HCl como fase aquosa. As nanoemuls��es foram obtidas a partir da dilui����o de microemuls��es com ��gua ou solu����o de HCl. Foi realizado estudo das tens��es superficiais, estudo das cin��ticas de rea����o, avalia����o da inje����o em rocha carbon��tica e remo����o de borra asf��ltica. As nanoemuls��es apresentaram tens��o superficial menor que suas microemuls��es de origem. As nanoemuls��es tiveram ��xito em retardar a rea����o entre CaCO3 e HCl, onde o sistema mais eficiente �� composto por UNT L90/OMS, Secbutanol, Querosene e solu����o de HCl. As nanoemuls��es foram eficientes em formar wormholes em plugs de carbonato calcitico com baixa permeabilidade natural. As wormholes proporcionaram incremento de permeabilidade alcan��ando valores de at�� 390 mD. O sistema ��cido apresentou bom resultado de remo����o de borra asf��ltica, mostrando o potencial das nanoemuls��es em remover esse tipo de dano. Conclui-se que os sistemas nanoemulsionados t��m grande potencial de aplica����o em acidifica����o de matriz.

Bi anisotropia em antenas de microfita retangular e estruturas circulares modificadas

The microstrip antennas in your simplest form consist of a ground plane and a dielectric substrate which supports a conductive tape. As these antennas have some limitations, this work presents a study of anisotropic substrates, as well as some results in microstrip antennas with circular patch, aiming to overcome these limitations, especially in applications at 4G technology. These anisotropic substrates are those in which electrical permittivity and magnetic permeability are represented by tensors of second order. The study consists of a theoretical analysis of substrates and development of a mathematical formalism, the Transverse Transmission Line Method, aimed the application of these substrates in microstrip antennas. Among the substrates used in this study, there are the ferrimagnetic and metamaterials, in which some miniaturizations of the antennas are achieved. For antennas with circular patch, are considered arrays and modified ground planes in order to achieve improvement in parameters, in particular, gain and bandwidth. Several simulations have been made and antennas were constructed so that the measured values could be compared with the simulated values.

Esquina edif��cio: uma proposta arquitet��nica para um edif��cio misto

Natal, como outras cidades metropolitanas brasileiras, sofreu nas ��ltimas d��cadas uma forte transforma����o impulsionada pelo mercado imobili��rio e pela ind��stria da constru����o civil. A produ����o de apartamentos em condom��nios fechados vem crescendo e tornando cada vez mais comum, no cen��rio urbano, a presen��a de torres residenciais (com extensos muros e grades, fachadas cegas e guaritas) que favorecem o ���desurbanismo���. Por outro lado, este tipo de empreendimento, o edif��cio multifamiliar, apresenta plantas baixas padronizadas as quais frequentemente s��o incoerentes com a diversidade de perfis dos usu��rios. A consequ��ncia disso s��o reformas e adequa����es nos apartamentos ap��s a entrega da obra. Diante deste contexto, elaborei uma proposta arquitet��nica, que �� apresentada nesta disserta����o, como alternativa a essa modalidade de produ����o que est�� se tornando dominante no Brasil e em outros pa��ses. Dois conceitos nortearam esta proposta: a) o conceito de urbanidade cujo objetivo no projeto arquitet��nico �� favorecer a percep����o do outro (por copresen��a e/ou coci��ncia) atrav��s da permeabilidade, acessos e passagens entre o edif��cio e o entorno. A maneira como os cheios (barreiras) se estruturam com os vazios foi trabalhada de modo que definissem propriedades espaciais cuja inten����o �� facilitar o encontro e a diversidade entre moradores e entre estes e os de fora, no entanto sem desconsiderar o problema da viol��ncia urbana e, consequentemente a import��ncia da promo����o de seguran��a para os usu��rios. b) o conceito de flexibilidade a fim de possibilitar ao consumidor final o desmembramento da unidade habitacional em duas e, em especial, a participa����o e ou escolha na concep����o do arranjo interno e da defini����o dos acabamentos do seu apartamento. Tudo isto durante a constru����o do empreendimento e ao longo da sua vida ��til, favorecendo assim o potencial de diversidade (grupos sociais), adaptabilidade a fases distintas da vida e durabilidade do edif��cio.

Avalia����o do desempenho de argamassas �� base de cimento Portland para rejuntamento de placas cer��micas tipo II com adi����o de p�� de borracha de pneus

In this work it is assessed the performance of Portland cement-based mortar to the grouting of type II ceramic plates with the addition of unusable tire rubber powder. It is presented a bibliographical review about the subject in which is done the theoretical and methodological foundation of the whole investigative process. The analyzed universe comprises a sample of mortar to the grouting of conventional ceramic plates type II (reference sample) and five more samples to the grouting of ceramic plates type II, which were made up of the addition of unusable tire rubber powder in the respective proportion (in mass) of 4%, 8%, 12%, 16% and 20%. These mortar samples were subject to the trials of determination of the consistency index (Brazilian Standard NBR 13276:2005), water retention ( Brazilian Standard NBR 14992 Attachment B:2003), permeability in 240 minutes (Brazilian Standard NBR 14992 Attachment G:2003), absorption of water by immersion (Brazilian Standard NBR 9781:2013), resistance to compression (Brazilian Standard NBR14992 Attachment D: 2003), resistance to traction in the flexion (Brazilian Standard NBR 13279:2005), resistance of traction adherence (Brazilian Standard NBR 14081 part 4:2012) and hardened mass density (Brazilian Standard NBR 13280: 2005). It has been found out from the analyzes of the results in the trial the following situation: the reference mortar used met the established requirements in the norms of specifications corresponding to only six from the eight parameters assessed in the research; the mortar with addition of 4,0% of tire rubber powder met the established requirements corresponding to only the resistance to compression and the resistance of adherence to traction. Thus, the other kinds of mortar with addition of 8,0 %, 12,0 %, 16,0 % and 20,0 % of tire rubber powder met the requirements of specifications corresponding to only the resistance to compression and the resistance of adherence to traction. This result concludes that the adding of tire rubber powder does not grant improvement to the mortar of type II grouting to the laying of ceramic plates.

Avalia����o do desempenho de argamassas �� base de cimento Portland para rejuntamento de placas cer��micas tipo II com adi����o de p�� de borracha de pneus

In this work it is assessed the performance of Portland cement-based mortar to the grouting of type II ceramic plates with the addition of unusable tire rubber powder. It is presented a bibliographical review about the subject in which is done the theoretical and methodological foundation of the whole investigative process. The analyzed universe comprises a sample of mortar to the grouting of conventional ceramic plates type II (reference sample) and five more samples to the grouting of ceramic plates type II, which were made up of the addition of unusable tire rubber powder in the respective proportion (in mass) of 4%, 8%, 12%, 16% and 20%. These mortar samples were subject to the trials of determination of the consistency index (Brazilian Standard NBR 13276:2005), water retention ( Brazilian Standard NBR 14992 Attachment B:2003), permeability in 240 minutes (Brazilian Standard NBR 14992 Attachment G:2003), absorption of water by immersion (Brazilian Standard NBR 9781:2013), resistance to compression (Brazilian Standard NBR14992 Attachment D: 2003), resistance to traction in the flexion (Brazilian Standard NBR 13279:2005), resistance of traction adherence (Brazilian Standard NBR 14081 part 4:2012) and hardened mass density (Brazilian Standard NBR 13280: 2005). It has been found out from the analyzes of the results in the trial the following situation: the reference mortar used met the established requirements in the norms of specifications corresponding to only six from the eight parameters assessed in the research; the mortar with addition of 4,0% of tire rubber powder met the established requirements corresponding to only the resistance to compression and the resistance of adherence to traction. Thus, the other kinds of mortar with addition of 8,0 %, 12,0 %, 16,0 % and 20,0 % of tire rubber powder met the requirements of specifications corresponding to only the resistance to compression and the resistance of adherence to traction. This result concludes that the adding of tire rubber powder does not grant improvement to the mortar of type II grouting to the laying of ceramic plates.

Evolu����es nas modelagens de substratos artificiais (metamateriais) com pr��ticas experimentais em antenas de microfita

Esse trabalho tem como objetivo apresentar configura����es de substratos diel��tricos inovadores projetados e fabricados a partir de estruturas metamateriais. Para isso, s��o avaliados diversos fatores que podem influenciar no seu desempenho. A princ��pio, foi feito um levantamento bibliogr��fico a respeito dos temas, que est��o relacionados com as pesquisas sobre: materiais diel��tricos, metamateriais e interferometria ��ptica. S��o estudados, pesquisados e desenvolvidos dois projetos experimentais propostos, que comprovam a efici��ncia de m��todos, para se alcan��ar a permeabilidade magn��tica negativa na forma����o de metamateriais. O primeiro projeto �� a produ����o de uma nova estrutura, com u anel ressoador triangular equilateral (Split Equilateral Triangle Resonator - SETR). O segundo projeto: aplica os princ��pios da interferometria ��ptica, especialmente, com o interfer��metro de Fabry-Perot. T��cnicas para obten����o dos dispositivos que complementam a placa metamaterial como substrato foram pesquisadas na literatura e exemplificadas principalmente por meio de simula����es e medi����es. Foram feitas compara����es, simula����es e medi����es de estruturas convencionais e especiais. As experi��ncias se concentram nas evolu����es e modelagens de substratos metamateriais com aplica����es em antenas de microfita. As melhorias de alguns par��metros de desempenho de antenas tamb��m s��o relatadas. As simula����es das antenas foram feitas nos programas computacionais comerciais. Os resultados medidos foram obtidos com um analisador vetorial de redes da Rhode and Schwarz modelo ZVB 14.

Evolu����es nas modelagens de substratos artificiais (metamateriais) com pr��ticas experimentais em antenas de microfita

Esse trabalho tem como objetivo apresentar configura����es de substratos diel��tricos inovadores projetados e fabricados a partir de estruturas metamateriais. Para isso, s��o avaliados diversos fatores que podem influenciar no seu desempenho. A princ��pio, foi feito um levantamento bibliogr��fico a respeito dos temas, que est��o relacionados com as pesquisas sobre: materiais diel��tricos, metamateriais e interferometria ��ptica. S��o estudados, pesquisados e desenvolvidos dois projetos experimentais propostos, que comprovam a efici��ncia de m��todos, para se alcan��ar a permeabilidade magn��tica negativa na forma����o de metamateriais. O primeiro projeto �� a produ����o de uma nova estrutura, com u anel ressoador triangular equilateral (Split Equilateral Triangle Resonator - SETR). O segundo projeto: aplica os princ��pios da interferometria ��ptica, especialmente, com o interfer��metro de Fabry-Perot. T��cnicas para obten����o dos dispositivos que complementam a placa metamaterial como substrato foram pesquisadas na literatura e exemplificadas principalmente por meio de simula����es e medi����es. Foram feitas compara����es, simula����es e medi����es de estruturas convencionais e especiais. As experi��ncias se concentram nas evolu����es e modelagens de substratos metamateriais com aplica����es em antenas de microfita. As melhorias de alguns par��metros de desempenho de antenas tamb��m s��o relatadas. As simula����es das antenas foram feitas nos programas computacionais comerciais. Os resultados medidos foram obtidos com um analisador vetorial de redes da Rhode and Schwarz modelo ZVB 14.

Estudo da influ��ncia de sistemas microemulsionados na molhabilidade de arenitos e na recupera����o avan��ada de petr��leo

Sandstone-type reservoir rocks are commonly responsible for oil accumulation. The wettability is an important parameter for the physical properties of the container, since it interferes in characteristics such as relative permeability to the aqueous phase, residual oil distribution in the reservoir, operating characteristics with waterflood and recovery of crude oil. This study applied different types of microemulsion systems - MES - in sandstone reservoirs and evaluated their influences on wettability and residual oil recovery. For this purpose, four microemulsion were prepared by changing the nature of ionic surfactants (ionic and nonionic). Microemulsions could then be characterized by surface tension analysis, density, particle diameter and viscosity in the temperature range 30�� C to 70�� C. The studied oil was described as light and the sandstone rock was derived from the Botucatu formation. The study of the influence of microemulsion systems on sandstone wettability was performed by contact angle measurements using as parameters the rock treatment time with the MES and the time after the brine surface contact by checking the angle variation behavior. In the study results, the rock was initially wettable to oil and had its wettability changed to mixed wettability after treatment with MES, obtaining preference for water. Regarding rock-MES contact time, it was observed that the rock wettability changed more when the contact time between the surface and the microemulsion systems was longer. It was also noted only a significant reduction for the first 5 minutes of interaction between the treated surface and brine. The synthesized anionic surfactant, commercial cationic, commercial anionic and commercial nonionic microemulsion systems presented the best results, respectively. With regard to enhanced oil recovery performance, all systems showed a significant percentage of recovered oil, with the anionic systems presenting the best results. A percentage of 80% recovery was reached, confirming the wettability study results, which pointed the influence of this property on the interaction of fluids and reservoir rock, and the ability of microemulsion systems to perform enhanced oil recovery in sandstone reservoirs.

Estudo da influ��ncia de sistemas microemulsionados na molhabilidade de arenitos e na recupera����o avan��ada de petr��leo

Sandstone-type reservoir rocks are commonly responsible for oil accumulation. The wettability is an important parameter for the physical properties of the container, since it interferes in characteristics such as relative permeability to the aqueous phase, residual oil distribution in the reservoir, operating characteristics with waterflood and recovery of crude oil. This study applied different types of microemulsion systems - MES - in sandstone reservoirs and evaluated their influences on wettability and residual oil recovery. For this purpose, four microemulsion were prepared by changing the nature of ionic surfactants (ionic and nonionic). Microemulsions could then be characterized by surface tension analysis, density, particle diameter and viscosity in the temperature range 30�� C to 70�� C. The studied oil was described as light and the sandstone rock was derived from the Botucatu formation. The study of the influence of microemulsion systems on sandstone wettability was performed by contact angle measurements using as parameters the rock treatment time with the MES and the time after the brine surface contact by checking the angle variation behavior. In the study results, the rock was initially wettable to oil and had its wettability changed to mixed wettability after treatment with MES, obtaining preference for water. Regarding rock-MES contact time, it was observed that the rock wettability changed more when the contact time between the surface and the microemulsion systems was longer. It was also noted only a significant reduction for the first 5 minutes of interaction between the treated surface and brine. The synthesized anionic surfactant, commercial cationic, commercial anionic and commercial nonionic microemulsion systems presented the best results, respectively. With regard to enhanced oil recovery performance, all systems showed a significant percentage of recovered oil, with the anionic systems presenting the best results. A percentage of 80% recovery was reached, confirming the wettability study results, which pointed the influence of this property on the interaction of fluids and reservoir rock, and the ability of microemulsion systems to perform enhanced oil recovery in sandstone reservoirs.