24 resultados para Irreversible structural changes
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
The application of composite materials and in particular the fiber-reinforced plastics (FRP) has gradually conquered space from the so called conventional materials. However, challenges have arisen when their application occurs in equipment and mechanical structures which will be exposed to harsh environmental conditions, especially when there is the influence of environmental degradation due to temperature, UV radiation and moisture in the mechanical performance of these structures, causing irreversible structural damage such as loss of dimensional stability, interfacial degradation, loss of mass, loss of structural properties and changes in the damage mechanism. In this context, the objective of this thesis is the development of a process for monitoring and modeling structural degradation, and the study of the physical and mechanical properties in FRP when in the presence of adverse environmental conditions (ageing). The mechanism of ageing is characterized by controlled environmental conditions of heated steam and ultraviolet radiation. For the research, it was necessary to develop three polymer composites. The first was a lamina of polyester resin reinforced with a short glass-E fiber mat (representing the layer exposed to ageing), and the other two were laminates, both of seven layers of reinforcement, one being made up only of short fibers of glass-E, and the other a hybrid type reinforced with fibers of glass-E/ fibers of curaua. It should be noted that the two laminates have the lamina of short glass-E fibers as a layer of the ageing process incidence. The specimens were removed from the composites mentioned and submitted to environmental ageing accelerated by an ageing chamber. To study the monitoring and modeling of degradation, the ageing cycles to which the lamina was exposed were: alternating cycles of UV radiation and heated steam, a cycle only of UV radiation and a cycle only of heated steam, for a period defined by norm. The laminates have already undergone only the alternating cycle of UV and heated steam. At the end of the exposure period the specimens were subjected to a structural stability assessment by means of the developed measurement of thickness variation technique (MTVT) and the measurement of mass variation technique (MMVT). Then they were subjected to the mechanical tests of uniaxial tension for the lamina and all the laminates, besides the bending test on three points for the laminates. This study was followed by characterization of the fracture and the surface degradation. Finally, a model was developed for the composites called Ageing Zone Diagram (AZD) for monitoring and predicting the tensile strength after the ageing processes. From the results it was observed that the process of degradation occurs Abstract Raimundo Nonato Barbosa Felipe xiv differently for each composite studied, although all were affected in certain way and that the most aggressive ageing process was that of UV radiation, and that the hybrid laminated fibers of glass-E/curaua composite was most affected in its mechanical properties
Resumo:
MELO, D. M. A. et al. Synthesis and charactezarion of lanthanum and yttrium doped Fe2O3 pigments. Cerâmica, São Paulo, v. 53, p. 79-82, 2007.
Resumo:
This dissertation examines the organizational innovation as a nonlinear process, which occurs in a social and political context and, therefore, socially immersed. Examines the case of shrimp in the state of RN, starting from the following problem: although the norteriograndense shrimp occupies the largest producer of farmed shrimp from Brazil, has a series of bottlenecks concerning the generation of industry innovation, concerning the social relationships and policies between the various actors in the network, whether private or public, and its consequences in terms of opportunity and limits generated for the innovative dynamics. The objective of the research is to understand how the social embeddedness of political actors affects norteriograndense shrimp within the context of structural relations, the industry generation of innovation, throughout its technological trajectory . The approach of social embeddedness balances atomised perspectives, undersocialized and oversocialized, of economic action, considering both the human capacity to act as sources of constraint, whose mechanisms are analyzed the structural and political. In methodological terms this is a case study, analyzed from the research literature, documentary and experimental. Primary data were collected through semi-structured interviews and analyzed in depth by the technique of content analysis. Was adopted a longitudinal approach, seeking to understand the phenomenon from the perspective of the subjects, describing it in an inductive process of investigation. After characterizing the sector and defining their technological trajectory, the analysis of the results followed its four stages: (1) Introduction of Technology: 1973-1980, (2) Intensification of Research: 1981-1991, (3) Technological Adaptation, 1992 -2003, (4) Technological Crisis: 2004-2009. A cross-sectional analysis along the evolutionary trajectory revealed the character of structural changes and policies over time, and implications on the generating process of innovation. Note that, the technological limit to which the sector reached requires changes in technology standards, but is more likely that the potiguar shrimp is entering a new phase of his career in technology rather than a new technological paradigm
Resumo:
The present dissertation analyzes the performance and acting of the Rio Grande do Norte Public Ministery, in the strategic perspective, while responsible Institution for the defense of the collective rights. The comprehension of this theme inserts in a context of modernization of the public administration, in which is inserted, as well as their functional and structural changes, in a reality of innovations there is passing the organizations, looking to rescue the legitimacy of the government organizations, aligning them to the democratic values of the society. It detaches the strategic administration and the public administration and it exposes the strategic performance about the central point of the study, focusing in the development of the organization in the last four years, and other relative subjects to the acting. It is a unic case study, framed in the characteristics of the qualitative approaches - descriptive and exploratory. The analysis showed, through the method of content analysis, by the criterion of thematic categorization, that MP / RN come developing in an intense way,and it detaches that the changes already happened reflect a good strategic acting of the Institution, especially in the structural and functional areas, showing the strategic conscience of this, although that is not still enough to consider it as a strategic organization, and it concludes that there is still a lot for doing, and that the occurrence of an administration typically strategic in the extent of MP/RN is possible, with the conscience and participation of all, members and servants
Resumo:
This work aimed to study the structure and dynamic of Phytoplankton and Bacterioplankton in a complete cycle of shrimp cultivation (Litopenaeus vannamei) and determine the environmental factors responsible for the structural changes of these communities. The study was realized in a saltwater shrimp farm (Macaíba, RN), between September/2005 and February/2006, and in a freshwater shrimp farm (Ceará Mirim, RN), between May/2007 and September 2007. The samplings were collected weekly in saltwater farm and every fifteen days in freshwater farm. Total phosphorus, chlorophyll a and environmental parameters (pH, dissolved oxygen, salinity, temperature, depth and water transparency) were measured. Qualitative and quantitative analysis of the phytoplankton and bacterioplankton were carried out. The Shannon-Wiener ecologic indexes of diversity and the Pielou equitability indexes were calculated to the phytoplankton. Bacterial density was determined by epifluorescence microscopy. The data were statistically analyzed by Pearson correlation and t-Test. Chlorophycea were predominat in salt water and in the captation/drainage point (24 to 99%). Diatoms had higher wealth. The species Choricystis minor had the highest occurrence (100%) and dominance (90-100%), thus showing its adaptation to the high temperatures, salinity and low water transparency conditions. Filamentous Cyanobacteria like Oscillatoria sp., Pseudoanabaena sp. and Phormidium sp. had constant levels. The negative correlation between chlorophycea and water transparency, and the positive correlation between chlorophyll a and salinity, showed that the phytoplankton was well adapted to the low transparency and to the high salinity. The bacterioplankton was negatively correlated with the total phosphorus and salinity. In freshwater, Cyanobacteria were predominant (>80%), presenting some producers of toxins species like Microcystis sp., Aphanizomenon sp., Cylindrospermopsis raciborskii e Anabaena circinalis. Cyanobacterial density and total phosphorus and chlorophyll a concentrations exceeded the maximum value allowed by legislation. The means of total phosphorus varied from 264 to 627 Wg.L-1 and the means of chlorophyll a oscillated between 22 and 182 Wg.L-1. The phytoplankton species were selected by low availability of the light, high pH, temperature and high availability of total phosphorus. The bacterioplankton showed high densities (5,13 x 107 to 8,50 x107 Bac.mL-1). The studied environments (ponds and rivers) presented a high level of trophic state based on the high concentrations of chlorophyll a and total phosphorus and cyanobacteria dominance. The composition of species in the ponds and rivers was similar, as well as high concentrations of total phosphorus and chlorophyll a, highlighting the pollution caused by the discharges of the farms in natural environment
Resumo:
Structural changes in waste for zeolites synthesis are subject of many studies carried out in the synthesis of molecular sieves. These materials are named molecular sieves because they have well defined pore sizes and they have the capacity of select molecules by its size. In this work, it was studied the synthesis processes of two types of molecular sieves: pillared acid clays using as starting material one natural montmorillonite clay and the synthesis of zeolites from a silico-aluminous residue. This residue is a byproduct of the extraction of lithium -spodumene. The preparation of pillared acid clays was performed in two steps: 1° acid treatment of clay samples (time and temperature studies) and 2°pilarization of them with Al13 (Keggin ion). The temperature and acid concentration affect the removal of cations in the structure and porosity of the material obtained. The analysis of X-ray diffraction (XRD) and infrared spectroscopy (IR), showed that increasing the severity of the acid treatment compromises the structural material. Also the pore size distribution is approximately uniform. Despite presenting a structural disorganization, the samples were pillared. As evidenced by XRD increasing the basal spacing, specific area and uniform porosity by adsorption of N2. Regarding the microporous molecular sieves were synthesized zeolites A and NaP1 from a silico-aluminous residue, a byproduct of extracting lithium. The temperature and time of agitation during the synthesis were the most important factors for obtaining zeolite A. The aging of the gel and the highest crystallization time promoted the formation of zeolite NaP1 using a Si / Al ratio = 3.2
Resumo:
The genus Saccharum belongs to Poaceae family. Sugarcane has become important monocultures in Brazil due to their products: ethanol and sugar. The production may change between different regions from Brazil. This difference is related to soil, climatic conditions and temperature that promotes oxidative stress that may induce an early flowering. The aim of this work was to identify the effects of oxidative stress. In order to analyse this, sugarcane plants were submitted to oxidative stress using hydrogen peroxide. After this treatment, the oxidative stress were analyzed Then, the plant responses were analyzed under different approaches, using morphophysiological, biochemical and molecular tools. Thus, sugarcane plants were grown under controlled conditions and until two months they were subjected first to a hydroponics condition for 24 hours in order to acclimation. After this period, these plants were submitted to oxidative stresse using 0 mM, 10 mM, 20 mM and 30 mM hydrogen peroxide during 8 hours. The histomorphometric analysis allowed us to verify that both root and leaf tissues had a structural changes as it was observed by the increased in cell volume, lignin accumulation in cell walls. Besides, this observation suggested that there was a change in redox balance. Also, it was analyzed the activity of the SOD, CAT and APX enzymes. It was observed an increase in the SOD activity in roots and it was also observed a lipid peroxidation in leaves and roots. Then, in order to identify proteins that were differently expressed in this conditions it was used the proteomic tool either by bidimensional gel or by direct sequencing using the Q-TOF EZI. The results obtained with this approach identified more than 3.000 proteins with the score ranging from 100-5000 ions. Some of the proteins identified were: light Harvesting; oxygenevolving; Thioredoxin; Ftsh-like protein Pftf precusor; Luminal-binding protein; 2 cys peroxiredoxin e Lipoxygenase. All these proteins are involved in oxidative stress response, photsynthetic pathways, and some were classified hypothetical proteins and/or unknown (30% of total). Thus, our data allows us to propose that this treatment induced an oxidative stress and the plant in response changed its physiological process, it made changes in tissue, changed the redox response in order to survival to this new condition
Resumo:
The freedom of concurrence, firstly conceived as a simple market fundament in productive systems that recognized the productive forces freedom of action, appears as a clear instrument of protection and fomentation of the market, recognizing the importance of the simultaneous existence of various economic forces such the proper capitalism reason of constitution. It has, thus, a directly role linked to the fundamental idea that the market and its productive forces needed of a protection against itself, because it exists inside the market situations and circumstances, provoked or not, that could prejudice and even annihilate the its existence and functioning, whilst a complex role of productive forces presents at all economic creation space. It was the primacy of the classic liberalism, the first phase of the capitalism. The Constitutions, in that historic moment, did not proclaim any interference at the economic scenario, simply because it recognized the existence of an economic freedom prepared to justify and guarantee the market forces, with its own rules. Based on the structural changes that occurred at the following historic moments, inside the constitutionally recognized capitalism, it was verified changes in the ambit of treatment of the freedom of concurrence principle that, in a progressive way, passes to present a configuration more concerned with socialist and developing ideas, as long as not only a market guarantee. It emerges a freedom of concurrence which aim is instrumental, in relation to its objectives and constitutional direction as a role, and not anymore stagnant and with isolated treatment, in special at the constitutional systems the present s clear aspects of social interventions and guarantor of fundamental rights more extensive and harmonious. That change is located at a space of state actuation much more ample and juridical important, this time comprehending the necessity of managing the productive scenario aiming to reach a national social and economic development effectively guarantor of fundamental rights for all citizens. Those Constitutions take as point of starting that the social and economic development, and not only anymore the economic growth, is the effective way for concretization of these rights. In that way it needs to be observed and crystallized by political and juridical tools that respect the ideological fundamental spirit of the Constitutional Charters. In that scenario that seeks for solutions of rights accomplishment, in special the social rights, the constitutional principle of freedom of concurrence has been seen as an instrument for reaching bigger values and directives, such as the social justice, which only can be real at a State that can implement a comprehensive and permanent social and economic development. The freedom of concurrence tries to valorize and defend something larger and consonant to the political values expressed in the Constitutional Charters with social character, which is the right to a social and economical sustainable development, guarantor of more clear and compromised collective benefits with social justice. The origin of that constitutional imposition is not only supported by vague orientations of the economic space, but as integrated to it, with basis formed of normative and principles posted and prepared to produce effects at the proper reason of the Constitution
Resumo:
As an effect of the growing interdependence in international relations, regional integration was conceived to face globalization, with a remarkable influence in politics and law, since the first steps of the European experience. In Latin America, regional integration ideas have blossomed in the 60 s. Among its experiences, MERCOSUL is the one with the most advanced objectives. However, MERCOSUL has not managed to achieve the objectives planned nor moved forward the integration process. Differently of what happened in Europe, in MERCOSUL the common market projected is concluded. It faced many disappointments throughout its brief history. As it matters to law, those were caused by the absence of supranationality, a mechanism that would allow MERCOSUL s decisions to be directly binding in the States with no need of bureaucratic proceedings to incorporate them to national legal systems. Among Latin American States, Brazil is probably the most resistant to integration process, due to Federal Constitution 1988 rigidity and legal professionals conservadorism towards opening legal system to international law. In Brazil hermeneutical standards are always based on national sovereignty and international law is referred as less important. The problems become more visible relating to taxation, a subject that plays an enormous role in integration process for its economic impact, demanding the execution of tax harmonization policies compatible to the integration levels aspired. However, because of the large number of tax rules in the Federal Constitution, structural changes initiatives face difficulties in order to be implemented. Actually, after two Constitutional Reforms on taxation, Brazil has not yet succeeded on promoting the necessary adaptations to regional integration. The research has confirmed the hypothesis that supranationality has indispensably to be adopted if Brazil really desires to move forward the integration process. But it has also been demonstrated that there are hermeneutical paths suitable to the constitutional profile which allow the adoption of supranationality, through the revision of the sovereignty traditional concept
Resumo:
Attention to the health of adolescents, based on paradigm flexneriano, needs to be overcome. Since the International Conference of Ottawa (1986), the literature is developing a discussion of the promotion of health, based on the paradigm of social production in health, suggests a design to overcome the health care traditional practices. Program Health of the Family PSF has this purpose to transmute the model of existing assistance, where the nurse is an essential element to the work done in the program. Around this context, it is our purpose to analyze the practice of nurse of the PSF for the promotion of health of adolescents, produced by a search of descriptive quantitative approach with the inclusion of qualitative data. Interviews were conducted with 9 nurses 3 units of health of the family USF, Mossoró-RN and applied questionnaires with 74 teenagers aged between 15 and 19 years old, with some nearby public schools where USF operate these nurses. The quantitative descriptions were transformed on tables, pictures and graphics using the program Excel (Microsoft) and the qualitative were worked through the technique of analyzing the content of Bardin (2004). The review was realized using the reference to promote health brought by the study. The results show that the most common problems that happen with teenagers are the drugs (33,8%), pregnancy (27,0%) and political problems-socio-economic-cultural issues (24,3%). Adolescents are spontaneous demand and rarely seek the USF. The actions presented by the nurses as, lectures and groups, are nothing comparing to the macro-problems presented by adolescents, and verticalized irregular. The nurses know the promotion of health generally, not explaining how operate it from its daily practice. Concluded that the practice of nurse of the PSF has not yet reach the promotion of health of the adolescent, being necessary to scheduling modules on the subject to continuous training of teams, professionals from USF, as well as teachers and other staff of schools, giving space to the participation of academic. The discussions should be socialized with the community to discuss possibilities of confrontation of the problems, which also require socio-structural changes. This research can contribute as work-diagnosis, which experienced the reality of care in nursing PSF to a specific group
Resumo:
Hard metals are the composite developed in 1923 by Karl Schröter, with wide application because high hardness, wear resistance and toughness. It is compound by a brittle phase WC and a ductile phase Co. Mechanical properties of hardmetals are strongly dependent on the microstructure of the WC Co, and additionally affected by the microstructure of WC powders before sintering. An important feature is that the toughness and the hardness increase simultaneously with the refining of WC. Therefore, development of nanostructured WC Co hardmetal has been extensively studied. There are many methods to manufacture WC-Co hard metals, including spraying conversion process, co-precipitation, displacement reaction process, mechanochemical synthesis and high energy ball milling. High energy ball milling is a simple and efficient way of manufacturing the fine powder with nanostructure. In this process, the continuous impacts on the powders promote pronounced changes and the brittle phase is refined until nanometric scale, bring into ductile matrix, and this ductile phase is deformed, re-welded and hardened. The goal of this work was investigate the effects of highenergy milling time in the micro structural changes in the WC-Co particulate composite, particularly in the refinement of the crystallite size and lattice strain. The starting powders were WC (average particle size D50 0.87 μm) supplied by Wolfram, Berglau-u. Hutten - GMBH and Co (average particle size D50 0.93 μm) supplied by H.C.Starck. Mixing 90% WC and 10% Co in planetary ball milling at 2, 10, 20, 50, 70, 100 and 150 hours, BPR 15:1, 400 rpm. The starting powders and the milled particulate composite samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to identify phases and morphology. The crystallite size and lattice strain were measured by Rietveld s method. This procedure allowed obtaining more precise information about the influence of each one in the microstructure. The results show that high energy milling is efficient manufacturing process of WC-Co composite, and the milling time have great influence in the microstructure of the final particles, crushing and dispersing the finely WC nanometric order in the Co particles
Resumo:
Catalytic processes are widely present in everyday life. This results in large number of studies seeking materials that may combine the low cost catalytic efficiency. Based on this assumption, the clays have long been used as catalysts, with its huge availability, diversity and possibility of improving their properties from structural changes, primarily responsible for this great use. Among the natural clays, vermiculite due to their characteristic properties (high cation exchange capacity and expansion), is suitable for various applications including as catalysts and catalyst supports. In this work, the acid leaching of clay vermiculite was performed, coming from Santa Luzia-PB, with nitric acid (2, 3 and 4 mol / L) and subsequent calcination of the materials obtained. The materials were named as Vx/400, where x is the acid concentration employed and 400 used in calcination temperature. The effectiveness of changes made was determined by XRD techniques, FT-IR, EDS, TG/DTG, nitrogen physisorption and DTP of n-butylamine. Acid leaching has improved some properties of the clay - specific area and acidity - but the control of the acid concentration used is of vital importance, since the highest concentration caused the partial destruction of vermiculite entailing a decline in their properties. For analysis of the catalytic activity of the modified clay was made a comparative study with the SBA -15 mesoporous materials, synthesized via hydrothermal method, using the pyrolysis of low density polyethylene (LDPE). The results showed that the acid plays a fundamental role in the conversion of the polymer into smaller molecules, the material V3/400 was more selective for the source monomer (ethylene) due to their increased acidity, which promotes more breaks bonds in the polymeric chain, while materials and V0/400 V2/400, lower acidity, showed higher selectivity to light hydrocarbons, the range of fuel (41.96 and 41.23%, respectively), due to less breakage and secondary condensation reactions chains; already V4/400 SBA-15/550 and resulted in lower percentages of light hydrocarbons and the partial destruction of the structure and low acidity, respectively, responsible for the inefficiency of materials
Resumo:
The knowledge of the rheological behavior of microemulsionated systems (SME) is of fundamental importance due to the diversity of industrial applications of these systems. This dissertation presents the rheological behavior of the microemulsionated system formed by RNX 95/alcohol isopropyl/p-toulen sodium sulfonate/kerosene/distilled water with the addition of polyacrylamide polymer. It was chosen three polymers of the polyacrylamide type, which differ in molar weight and charge density. It was studied the addition of these polymers in relatively small concentration 0,1% in mass and maximum concentration of 2,0%. It was made analysis of flow to determine the appearing viscosities of the SME and rheological parameters applying Bingham, Ostwald de Waale and Herschell-Buckley models. The behavior into saline environment of this system was studied for a solution of KCl 2,0%, replacing the distilled water. It was determined the behavior of microemulsions in relation with the temperature through curves of flow in temperatures of 25 to 60ºC in variations of 5ºC. After the analysis of the results the microemulsion without the addition of polymer presented a slight increase in its viscosity, but it does not mischaracterize it as a Newtonian fluid. However the additive systems when analyzed with low concentration of polymer adjusted well to the applied models, with a very close behavior of microemulsion. The higher concentration of the polymer gave the systems a behavior of plastic fluid. The results of the temperature variation point to an increase of viscosity in the systems that can be related to structural changes in the micelles formed in the own microemulsion without the addition of polymer
Resumo:
The regeneration of bone defects with loss of substance remains as a therapeutic challenge in the medical field. There are basically four types of grafts: autologous, allogenic, xenogenic and isogenic. It is a consensus that autologous bone is the most suitable material for this purpose, but there are limitations to its use, especially the insufficient amount in the donor. Surveys show that the components of the extracellular matrix (ECM) are generally conserved between different species and are well tolerated even in xenogenic recipient. Thus, several studies have been conducted in the search for a replacement for autogenous bone scaffold using the technique of decellularization. To obtain these scaffolds, tissue must undergo a process of cell removal that causes minimal adverse effects on the composition, biological activity and mechanical integrity of the remaining extracellular matrix. There is not, however, a conformity among researchers about the best protocol for decellularization, since each of these treatments interfere differently in biochemical composition, ultrastructure and mechanical properties of the extracellular matrix, affecting the type of immune response to the material. Further down the arsenal of research involving decellularization bone tissue represents another obstacle to the arrival of a consensus protocol. The present study aimed to evaluate the influence of decellularization methods in the production of biological scaffolds from skeletal organs of mice, for their use for grafting. This was a laboratory study, sequenced in two distinct stages. In the first phase 12 mice hemi-calvariae were evaluated, divided into three groups (n = 4) and submitted to three different decellularization protocols (SDS [group I], trypsin [Group II], Triton X-100 [Group III]). We tried to identify the one that promotes most efficient cell removal, simultaneously to the best structural preservation of the bone extracellular matrix. Therefore, we performed quantitative analysis of the number of remaining cells and descriptive analysis of the scaffolds, made possible by microscopy. In the second stage, a study was conducted to evaluate the in vitro adhesion of mice bone marrow mesenchymal cells, cultured on these scaffolds, previously decellularized. Through manual counting of cells on scaffolds there was a complete cell removal in Group II, Group I showed a practically complete cell removal, and Group III displayed cell remains. The findings allowed us to observe a significant difference only between Groups II and III (p = 0.042). Better maintenance of the collagen structure was obtained with Triton X-100, whereas the decellularization with Trypsin was responsible for the major structural changes in the scaffolds. After culture, the adhesion of mesenchymal cells was only observed in specimens deccelularized with Trypsin. Due to the potential for total removal of cells and the ability to allow adherence of these, the protocol based on the use of Trypsin (Group II) was considered the most suitable for use in future experiments involving bone grafting decellularized scaffolds
Resumo:
Seeking to explain the causes leading to the developme nt and attempt to understand it, some economists were organized around central ideas, culminating therefore in the development of economic theories. The knowledge accumulated over the work by these scholars will make a significant contribution in shaping t he thinking of Celso Monteiro Furtado . Furtado developed numerous studies trying to understand the dynamics of underdeveloped structures, what their basic characteristics and the main factors responsible for the perpetuation of the status quo of these stru ctures. Starting from the question "What remains of underdevelopment characteristics in Brazil in the light of the thought of Celso Furtado?", This work is guided by the hypothesis that Brazil has not suffered between 2001 and 2012, significant structural changes that it could classifies it as a developed country. It has been for this work as a general objective to analyze the underdevelopment of elements that persist in Brazil in the light of the thought of Furtado. And as specific, characterize economic d evelopment, from the study of the classical schools, Marxist, neoclassical, Kaleckian, Keynesian and ECLAC of economic thought; describe the economic underdevelopment in light of Celso Furtado ideas; and, finally, evaluate from the particular epistemology of thought Furtado Brazilian economic reality, with emphasis on the analysis of underdevelopment elements. It was found that although there have been important advances in some sectors, the country maintains a significant structural heterogeneity. Hence th e relevance of Furtado's contribution to understanding the economic underdevelopment, because he is still a constant in our reality.