Paulo Emílio V. de Miranda

Oxidação direta do etanol no anodo de PaCOS

Electro catalysts electrodes were developed in this work, using ceria and Cu, for the direct oxidation of ethanol in solid oxide fuel cells (SOFC). An alternative method developed by Gortes et al [1] was applied to the production of the compound Cu-CeO2-YSZ (8% mol yttria stabilized zirconia). A YSZ porous support was prepared, from a ceramic suspension containing YSZ powder, maize starch and dispersant applied by serigraphy over one of the faces of the dense YSZ electrolyte. It was then calcined to remove the volatile elements and finally sintered. On the other side of the electrolyte a multifunctional cathode made of a composite material, La0,8Sr0,2MnO3+δ/Zr2O3-Y2O3, was applied. The first layer consisted of a functional cathode film of LSM/YSZ (50/50% by mass), the second layer being a pure cathode of LSM (La0.8Sr0.2MnO3). Over the porous support of YSZ, successive impregnations with an aqueous solution of ceria nitrate were applied. Afterwards, similarly, impregnations with an aqueous solution of copper were applied, to obtain the desired weight percentage concentration for each element. The porous support was characterized by Scanning Electron Microscopy (SEM) through the analysis of surface and fracture, where it was observed the porous structure formed due to the use of particles of starch. The amount, morphology and spatial distribution of elements, were analyzed by Energy Dispersive Spectroscopy (EDS) with mapping, showing the concentration of ceria, copper and YSZ throughout the volume of the anode. The Suitability to the use of fuel ethanol and hydrogen in the La0,8Sr0,2MnO3/YSZ/Cu-CeO2-YSZ cell was analyzed by the electrochemical performance of the open circuit potential, current density and power density.

Fatigue analysis of aluminum drill pipes

An experimental program was performed to investigate the fundamental fatigue mechanisms of aluminum drill pipes. Initially, the fatigue properties were determined through small-scale tests performed in an optic-mechanical fatigue apparatus. Additionally, full-scale fatigue tests were carried out with three aluminum drill pipe specimens under combined loading of cyclic bending and constant axial tension. Finally, a finite element model was developed to simulate the stress field along the aluminum drill pipe during the fatigue tests and to estimate the stress concentration factors inside the tool joints. By this way, it was possible to estimate the stress values in regions not monitored during the fatigue tests.

Fuels - essential materials to supply energy to our society

Paulo Emilio V. de Miranda Editor-in-Chief Revista Materia pmiranda@labh2.coppe.ufrj.br Among the vast variety of materials that are studied and characterized, fuels represent a special class due to their essential character to the existence and survival of our society, which require a progressively growing amount of energy to produce goods, services, food and guaranty the functioning of machines, equipment and vehicles. Although nuclear fuels and water are utilized to generate electric energy in large scale and alcohols, vegetable oils and animal fat were and still are used for energetic means, the world scene has been dominated for centuries by the wood and, subsequently, by the fossil fuels, coal, oil and natural gas. These, normally reacting with oxygen, provide the energetic potential required by liberating for human use part of the chemical energy they contain. If one considers the recent period from the Industrial Revolution on, the characteristic depicted in Figure 1 will be found. Figure 1 shows adapted drawings from Gupta [1], average energy density data [1-3], presents the years of maximum global supply for each fuel with projections from the literature [4] and an own made one and includes hydrogen as the energy vector of the future. It is worth mentioning here that hydrogen is not a primary fuel such as the other ones presented in Figure 1, because it requires a source of energy to be produced from the water, from fossil fuels or from biomass to play the role of an energy carrier. Several important aspects can be driven from an analysis of Figure 1, such as: 1. The chemical complexity of the fuels considered decrease strongly as the years go by. Wood and coal possess chemical configurations much more complex than the fuels that came afterwards; 2. There is an important decrease on the carbon content, establishing a progressive decarbonization of the fuels used by our society; 3. The energy content that each fuel offers grows very significantly in the oil and natural gas era and have potential for a new an important leap with the use of hydrogen. The energy density values for coal, oil and natural gas represent the average obtained from the ten greater world producers of these fuels [3]; 4. The hydrogen content in the fuels also increases progressively, to become majoritarian in oil and in natural gas, the latter being essentially composed of methane. Hydrogen is then presented as the fuel gas of the future and initiates a new era for humankind; 5. The fuels are being simultaneously used by our society, that is, still today we use wood as an energy resource. However, there has been a specific period in which a certain fuel has dominated the world scene, by being utilized to supply the major amount of energy consumed in the world. This has happened with wood in the dawn of the Industrial Revolution, by 1850; with coal until the moment that the vehicular transportation brought the use of the twentieth century’s liquid fuel, by 1930; and with oil in the beginning of the present millennium. Nowadays, we are right in the methane era, as the majoritarian element in natural gas, synthesis gas, shale gas and in biogases, for which the maximum in the world supply is expected to occur by the middle of the twenty first century. An extension of this scenario could be imagined if the methane hydrate, existent in immense amounts on the oceans bottom, would become technical and commercially feasible to be explored. It is worth mentioning that the decline in the use of fossil fuels occurs even though they continue to be available in the amount needed, because environmental driven motivations exist to induce their substitution, enlarging the possibilities for the use of renewable energies. Based on an analysis of the kinetics of evolution of the fuels that have been used in large scale up to the present, it is proposed that the humankind will have its energetic needs essentially supplied by the ultimate and inexhaustible fuel, hydrogen, by 2080. It should be highlighted, though, that the beginning of the hydrogen era will not involve only the direct use of hydrogen, but specially that of compounds that contain it in high density. The hydrogen era also opens opportunity for more efficient use of energy and with smaller environmental impact, letting emerge more sustainable ways of energy exploitation. In addition to that, there will be a very much important change of geopolitical character based on the fact that hydrogen may be produced from very many different raw materials that are available in all countries of the world, contrarily to the very much localized occurrenceEntre la grande variedad de materiales que son estudiados y caracterizados, los combustibles representan una clase especial debido a su carácter esencial para la existencia y sobrevivencia de nuestra sociedad, la cual requiere progresivamente cuantidades crecentes de energía para producir bienes, servicios, víveres y garantizar el funcionamiento de máquinas, equipos y vehículos. Aunque los combustibles nucleares y el agua sean utilizados para la generación de energía eléctrica en larga escala y los alcoholes, oleos vegetales y las gorduras de origen animal fueran y siguen siendo usados para fines energéticos, la escena mundial ha sido dominada por siglos por la madera y, subsecuentemente, por los combustibles fósiles, el carbón, el petróleo y el gas natural. Esos, normalmente reaccionando con el oxígeno, proveen el potencial energético requerido al liberar para uso humano parte de la energía química que contienen. El enfoque en época reciente, a partir de la Revolución Industrial, muestra características descritas en la Figura 1, la cual utilizó diseños adaptados de las estructuras químicas de los combustibles de Gupta [1], datos medianos de densidad energética [1-3], presenta los años de máximo suministro mundial para cada combustible con proyecciones de la literatura [4] y propia e incluye el hidrógeno como el vector energético del futuro. Vale resaltar aquí que el hidrógeno no es un combustible primario como los otros presentados en la Figura 1, pues requiere una fuente de energía para que sea producido a partir del agua, de combustibles fósiles o de biomasas para actuar como un portador de energía.

Combustíveis - materiais essenciais para prover energia à nossa sociedade

Paulo Emilio V. de Miranda Editor-in-Chief Revista Materia pmiranda@labh2.coppe.ufrj.br Among the vast variety of materials that are studied and characterized, fuels represent a special class due to their essential character to the existence and survival of our society, which require a progressively growing amount of energy to produce goods, services, food and guaranty the functioning of machines, equipment and vehicles. Although nuclear fuels and water are utilized to generate electric energy in large scale and alcohols, vegetable oils and animal fat were and still are used for energetic means, the world scene has been dominated for centuries by the wood and, subsequently, by the fossil fuels, coal, oil and natural gas. These, normally reacting with oxygen, provide the energetic potential required by liberating for human use part of the chemical energy they contain. If one considers the recent period from the Industrial Revolution on, the characteristic depicted in Figure 1 will be found. Figure 1 shows adapted drawings from Gupta [1], average energy density data [1-3], presents the years of maximum global supply for each fuel with projections from the literature [4] and an own made one and includes hydrogen as the energy vector of the future. It is worth mentioning here that hydrogen is not a primary fuel such as the other ones presented in Figure 1, because it requires a source of energy to be produced from the water, from fossil fuels or from biomass to play the role of an energy carrier. Several important aspects can be driven from an analysis of Figure 1, such as: 1. The chemical complexity of the fuels considered decrease strongly as the years go by. Wood and coal possess chemical configurations much more complex than the fuels that came afterwards; 2. There is an important decrease on the carbon content, establishing a progressive decarbonization of the fuels used by our society; 3. The energy content that each fuel offers grows very significantly in the oil and natural gas era and have potential for a new an important leap with the use of hydrogen. The energy density values for coal, oil and natural gas represent the average obtained from the ten greater world producers of these fuels [3]; 4. The hydrogen content in the fuels also increases progressively, to become majoritarian in oil and in natural gas, the latter being essentially composed of methane. Hydrogen is then presented as the fuel gas of the future and initiates a new era for humankind; 5. The fuels are being simultaneously used by our society, that is, still today we use wood as an energy resource. However, there has been a specific period in which a certain fuel has dominated the world scene, by being utilized to supply the major amount of energy consumed in the world. This has happened with wood in the dawn of the Industrial Revolution, by 1850; with coal until the moment that the vehicular transportation brought the use of the twentieth century’s liquid fuel, by 1930; and with oil in the beginning of the present millennium. Nowadays, we are right in the methane era, as the majoritarian element in natural gas, synthesis gas, shale gas and in biogases, for which the maximum in the world supply is expected to occur by the middle of the twenty first century. An extension of this scenario could be imagined if the methane hydrate, existent in immense amounts on the oceans bottom, would become technical and commercially feasible to be explored. It is worth mentioning that the decline in the use of fossil fuels occurs even though they continue to be available in the amount needed, because environmental driven motivations exist to induce their substitution, enlarging the possibilities for the use of renewable energies. Based on an analysis of the kinetics of evolution of the fuels that have been used in large scale up to the present, it is proposed that the humankind will have its energetic needs essentially supplied by the ultimate and inexhaustible fuel, hydrogen, by 2080. It should be highlighted, though, that the beginning of the hydrogen era will not involve only the direct use of hydrogen, but specially that of compounds that contain it in high density. The hydrogen era also opens opportunity for more efficient use of energy and with smaller environmental impact, letting emerge more sustainable ways of energy exploitation. In addition to that, there will be a very much important change of geopolitical character based on the fact that hydrogen may be produced from very many different raw materials that are available in all countries of the world, contrarily to the very much localized occurrenceEntre la grande variedad de materiales que son estudiados y caracterizados, los combustibles representan una clase especial debido a su carácter esencial para la existencia y sobrevivencia de nuestra sociedad, la cual requiere progresivamente cuantidades crecentes de energía para producir bienes, servicios, víveres y garantizar el funcionamiento de máquinas, equipos y vehículos. Aunque los combustibles nucleares y el agua sean utilizados para la generación de energía eléctrica en larga escala y los alcoholes, oleos vegetales y las gorduras de origen animal fueran y siguen siendo usados para fines energéticos, la escena mundial ha sido dominada por siglos por la madera y, subsecuentemente, por los combustibles fósiles, el carbón, el petróleo y el gas natural. Esos, normalmente reaccionando con el oxígeno, proveen el potencial energético requerido al liberar para uso humano parte de la energía química que contienen. El enfoque en época reciente, a partir de la Revolución Industrial, muestra características descritas en la Figura 1, la cual utilizó diseños adaptados de las estructuras químicas de los combustibles de Gupta [1], datos medianos de densidad energética [1-3], presenta los años de máximo suministro mundial para cada combustible con proyecciones de la literatura [4] y propia e incluye el hidrógeno como el vector energético del futuro. Vale resaltar aquí que el hidrógeno no es un combustible primario como los otros presentados en la Figura 1, pues requiere una fuente de energía para que sea producido a partir del agua, de combustibles fósiles o de biomasas para actuar como un portador de energía.

Particulate materials: threatening products resulting from burned fuels

Los combustibles fósiles, tales como el carbón, los derivados de petróleo y el gas natural son actualmente extensamente utilizados por nuestra sociedad para la generación de electricidad y calor, pero también para los diferentes medios de transportes individuales y masivos. Desde la Revolución Industrial las máquinas térmicas consumen grandes cuantidades de esos combustibles [1], contribuyendo al desarrollo de innumerables actividades industriales, profesionales, personales y de ocio de la vida moderna, las cuales han crecido de forma continua y explosiva durante el siglo XX. Pero, el inicio del siglo XXI clama por calidad, en pleno desafío de necesidades cada vez más grandes; pero apuntando a la eficiencia, en lugar del derroche actual derivado de pérdidas inadmisibles; y por un menor impacto ambiental que contribuya a una reducción en la diseminación de enfermedades y de la destrucción de los ecosistemas terrestres, fluviales, lacustres y marinos, como se viene observando.Paulo Emilio V. de Miranda Editor-in-Chief Revista Materia E-mail: pmiranda@labh2.coppe.ufrj.br The fossil fuels, such as coal, oil derivatives and natural gas are nowadays extensively used by our society for electricity and heat generation, and also for a variety of private and mass transportation. Since the Industrial Revolution, thermal machines consume huge amounts of these fuels [1], providing a myriad of modern life industrial, professional, personal and leisure activities, which have grown continuously and explosively dur-ing the 20th century. But the beginning of the 21st century claims for quality, within the challenge of requir-ing each time more quantity; for efficiency, instead of nowadays wastefulness that is responsible for unal-lowable losses; and for low bio-environmental impact, instead of the potential dissemination of diseases and the destruction of terrestrial, fluvial, lacunar and oceanic ecosystems, as it has been observed. Some science and engineering areas stand out, being instigated to offer innovative solutions, among which for biocompatible and biodegradable materials to improve quality and extend our life time and yet to guaran-tee adequate reinsertion into the environment by recycling. In addition to that, nanoscience and nanotechnol-ogy also impact on these same themes and still others, such as catalysts in an attempt of better cleaning harm-ful products created by the combustion of fossil fuels in thermal machines. Such combustion produces partic-ulate materials, which come with a series of other liquid and gaseous products which are malefic by them-selves, and might be transformed in other products that are even more deleterious. As an example, the reac-tive combination of products from the combustion of fossil fuels also generates ozone in our environment, which is a strong local contaminant and, alternatively, volatizes products that destroy the stratospheric ozone layer, which is important to protect us from the malefaction caused by ultraviolet solar irradiation. Among the particulate materials generated in abundance in the important urban centers by the use of motor vehicles, by the abrasion and suspension of asphalt particles, as well as in commercial, service and industrial activities, more importance is given nowadays to those with sizes of up to 2.5 µm. These are easily inhaled, going through our whole respiratory system until the alveolus, being mainly responsible by the occurrence of respiratory and cardiac illnesses and eventually contributing to injure the human life. They are made of a mi-crometric solid carbon particle with condensed hydrocarbons on its surface, still bearing adhered particles of liquid hydrocarbons that are soluble in organic media, hydrated sulfates and, eventually, small particles of toxic heavy metals. In addition to that, they play the role of bacteria, viruses and toxic chemical products carriers and also pollute the water, the soil, plants and food, besides the air. Approaching scientific themes from any area of knowledge associated to energetic and environmental sub-jects require clear prove for the anthropogenic responsibility in generating causes, so that the effects are well determined. For this reason, I’ve searched information with high statistic meaning, which had been obtained with well proven methodologies by trusted research groups, in urban centers that are representative of tech-nology-based modern life, in order to quantify and characterize the pollution caused by particulate materials and their effects. I’ve found these characteristics in a project named Aphekom [2], developed in 25 European cities, through the years of 2004 to 2006, whose results were conveniently reported and analyzed [3]. I’ve manipulated the tables and the results published [3] to make Figure 1, which shows data relative to the quan-titative average of the level of particulate materials with sizes up to 2.5 µm – PM2.5 – , expressed in µg/cm3, in suspension in air in each city studied, with indication of the maximum acceptable level proposed by the World Health Organization – WHO, equal to 10 µg/cm3, superposed to the data of human mortality by 100.000 inhabitants, relative only to respiratory and cardiac problems, which are supposed to be the most affected by this type of pollution. It may be verified that the majority of the cities studied presented air pollu-tion levels superior to the maximum level established by the WHO and also that there is a good correlation

Fabricação de suspensões cerâmicas para anodos de PaCOS suportadas pelo eletrólito

O presente trabalho tem como objetivo principal estudar e desenvolver um metodo de fabricacao de suspensoes cerâmicas para anodos de PaCOS para impressao sobre eletrolitos planos atraves de serigrafia, que e uma tecnica simples e de facil escalabilidade, alem de ter baixo custo e resultar em boas propriedades eletrocataliticas dos componentes assim processados. As suspensoes cerâmicas para o anodo foram fabricadas com oxido de niquel preparado no laboratorio do GECAT na UFBA e com zirconia estabilizada com itria (ZEI), ceria dopada com gadolinio (CDG) e dispersante comerciais. Estas foram processadas em moinho planetario de bolas. Foram utilizados dois tipos de zirconia estabilizada com itria para o anodo, uma com 4,3%mol de itria e tamanho medio de particula de 0,5 µm e outra com 9,3%mol de itria e tamanho medio de particula de 8 µm. Alem disso, outra suspensao foi fabricada com YSZ com 9,3%mol de itria fazendo-se uma adicao de 5% em peso de GDC. Eletrolitos comerciais de zirconia estabilizada com 8%mol de itria foram usados como suportes e para o catodo foi utilizada uma suspensao comercial de manganita de lantânio dopada com estroncio (LSM) de estequiometria La0,8Sr0,2MnO3. As pilhas foram testadas a 950°C sob atmosfera de hidrogenio e de metano para se determinar o desempenho eletroquimico da pilha a combustivel atraves dos graficos de potencial e de densidade de potencia em funcao da densidade de corrente. Analises de microscopia otica e microscopia eletronica de varredura para os eletrodos foram realizadas para se determinar a morfologia dos mesmos e a integridade apos a utilizacao.

Reconstrução digital de volume de eletrodo de PaCOS para cálculo de porosidade e tortuosidade

The aim of this work is to make tortuosity and porosity measurements by the use of digital volume reconstruction technique. It can be applied on real SOFC electrodes where the sample is sliced by focused ion beam (FIB). The reconstruction is done from the images of each layer of the sample generated by FIB. The geometric parameters, such as porosity and tortuosity, were calculated from a stack of binary images. Porosity was obtained by the ratio between the voxels concerned to pores and the total sample volume. Tortuosity was measured by the use of the Random Walkers algorithm that simulates molecular diffusion conditions without adding a preferential direction bias. The use of 3D reconstruction provided results of porosity calculation more accurate than the traditional classification in two dimensions. The diffusional model described by Random Walkers algorithm represented coherent and well acceptable values for tortuosity.

Materiais particulados: produtos ameaçadores resultantes da queima de combustíveis

Los combustibles fósiles, tales como el carbón, los derivados de petróleo y el gas natural son actualmente extensamente utilizados por nuestra sociedad para la generación de electricidad y calor, pero también para los diferentes medios de transportes individuales y masivos. Desde la Revolución Industrial las máquinas térmicas consumen grandes cuantidades de esos combustibles [1], contribuyendo al desarrollo de innumerables actividades industriales, profesionales, personales y de ocio de la vida moderna, las cuales han crecido de forma continua y explosiva durante el siglo XX. Pero, el inicio del siglo XXI clama por calidad, en pleno desafío de necesidades cada vez más grandes; pero apuntando a la eficiencia, en lugar del derroche actual derivado de pérdidas inadmisibles; y por un menor impacto ambiental que contribuya a una reducción en la diseminación de enfermedades y de la destrucción de los ecosistemas terrestres, fluviales, lacustres y marinos, como se viene observando.Paulo Emilio V. de Miranda Editor-in-Chief Revista Materia E-mail: pmiranda@labh2.coppe.ufrj.br The fossil fuels, such as coal, oil derivatives and natural gas are nowadays extensively used by our society for electricity and heat generation, and also for a variety of private and mass transportation. Since the Industrial Revolution, thermal machines consume huge amounts of these fuels [1], providing a myriad of modern life industrial, professional, personal and leisure activities, which have grown continuously and explosively dur-ing the 20th century. But the beginning of the 21st century claims for quality, within the challenge of requir-ing each time more quantity; for efficiency, instead of nowadays wastefulness that is responsible for unal-lowable losses; and for low bio-environmental impact, instead of the potential dissemination of diseases and the destruction of terrestrial, fluvial, lacunar and oceanic ecosystems, as it has been observed. Some science and engineering areas stand out, being instigated to offer innovative solutions, among which for biocompatible and biodegradable materials to improve quality and extend our life time and yet to guaran-tee adequate reinsertion into the environment by recycling. In addition to that, nanoscience and nanotechnol-ogy also impact on these same themes and still others, such as catalysts in an attempt of better cleaning harm-ful products created by the combustion of fossil fuels in thermal machines. Such combustion produces partic-ulate materials, which come with a series of other liquid and gaseous products which are malefic by them-selves, and might be transformed in other products that are even more deleterious. As an example, the reac-tive combination of products from the combustion of fossil fuels also generates ozone in our environment, which is a strong local contaminant and, alternatively, volatizes products that destroy the stratospheric ozone layer, which is important to protect us from the malefaction caused by ultraviolet solar irradiation. Among the particulate materials generated in abundance in the important urban centers by the use of motor vehicles, by the abrasion and suspension of asphalt particles, as well as in commercial, service and industrial activities, more importance is given nowadays to those with sizes of up to 2.5 µm. These are easily inhaled, going through our whole respiratory system until the alveolus, being mainly responsible by the occurrence of respiratory and cardiac illnesses and eventually contributing to injure the human life. They are made of a mi-crometric solid carbon particle with condensed hydrocarbons on its surface, still bearing adhered particles of liquid hydrocarbons that are soluble in organic media, hydrated sulfates and, eventually, small particles of toxic heavy metals. In addition to that, they play the role of bacteria, viruses and toxic chemical products carriers and also pollute the water, the soil, plants and food, besides the air. Approaching scientific themes from any area of knowledge associated to energetic and environmental sub-jects require clear prove for the anthropogenic responsibility in generating causes, so that the effects are well determined. For this reason, I’ve searched information with high statistic meaning, which had been obtained with well proven methodologies by trusted research groups, in urban centers that are representative of tech-nology-based modern life, in order to quantify and characterize the pollution caused by particulate materials and their effects. I’ve found these characteristics in a project named Aphekom [2], developed in 25 European cities, through the years of 2004 to 2006, whose results were conveniently reported and analyzed [3]. I’ve manipulated the tables and the results published [3] to make Figure 1, which shows data relative to the quan-titative average of the level of particulate materials with sizes up to 2.5 µm – PM2.5 – , expressed in µg/cm3, in suspension in air in each city studied, with indication of the maximum acceptable level proposed by the World Health Organization – WHO, equal to 10 µg/cm3, superposed to the data of human mortality by 100.000 inhabitants, relative only to respiratory and cardiac problems, which are supposed to be the most affected by this type of pollution. It may be verified that the majority of the cities studied presented air pollu-tion levels superior to the maximum level established by the WHO and also that there is a good correlation

A KMS to support collaborative innovation - The design of the Brazilian Solid Oxide Fuel Cell case

Sources of alternative, clean and smart energies are a demand on our modern world. And as a design project, collaboration and knowledge management are elements that improve the work on multidisciplinary teams. This work describes a collaborative project to construct a Brazilian Solid Oxide Fuel Cell, its problems and the solution created to enable a collaborative work on a national context.

Citation of articles published in the SciELO library

The Scientific Electronic Library Online – SciELO – is a model for cooperative electronic publishing of scientific journals on the Internet. Its target region is Latin America and Caribbean countries. The Journal Materia, as part of SciELO, has noted a long standing practice of its authors that deserve a critical analysis. I refer myself to the fact that most articles published in Materia, as well as in other journals presented by SciELO, mainly make use in their texts of bibliographic references from the Northern Hemisphere. This is certainly because the scientific journals from Europe, from parts of Asia and from North America have been pioneers and accumulate very many years of experience in this activity, having reached in several cases a high level of quality, gathering much reputation. It is also true that many researchers from Latin America and Caribbean countries have had, directly or indirectly, their scientific studies connected to important institutions and researchers from those regions and also that advantageous scientific cooperation links were kept, reaching generations of researchers from our continent. As a function of that, it is expected that the research works from the Northern Hemisphere will follow on as important references for the science published in the SciELO journals. However, it is also very much important for our scientific community to criticize, evaluate and cite the results from our own production. This will serve to help to increase the level of the science that we produce and also to direct the young researchers from our region to our own scientific works, eventually even facilitating future cooperative works, exempt of any excluding view and keeping, of course, the advantageous cooperation with other regions from the world. As a function of what was expressed above, I’d like to invite the authors of future articles to be published in the Journal Materia to research more deeply the content already published in this and in other SciELO journals and to also use them, as freely as it has been done with articles published in the Northern Hemisphere, as bibliographic references in their texts.