999 resultados para Ponte metálica. Aspectos históricos. Processos construtivos. Propriedades tecnológicas


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The industrial production of ornamental rocks and the burning of coffee husk generate waste that is discarded into the environment. However, with the study of the incorporation of these residues in ceramic products, may be found an alternative to reducing environmental impacts and detrimental effects on human health caused by its indiscriminate disposal of waste in nature. Thus, this work aimed to study the addition of ashes of the coffee husk and granite residue in matrix of red ceramic. The raw materials were dry milled and sieved to mesh 100. To characterize the raw materials were carried out analyzes of X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis (PSA), differential thermal analysis (DTA) and thermogravimetric analysis (TG). Six formulations were prepared where the clay content was kept constant (70%wt) and ashes contents and granite residue varied from 10, 15, 20 and 30%. Dilatometrics analyzes were performed at four selected formulations, containing them: 100% clay (A100); 70% clay and 30% ashes (A70C30); 70% clay and 30% granite residue (A70G30); and 70% clay, 15% granite residue and 15% ashes (A70G15C15). The samples were prepared by uniaxial compaction with pressure of 25 MPa, and fired at temperatures of 800°C, 850ºC, 900ºC, 950ºC, 1000ºC and 1100°C. Assays were performed to determine the linear shrinkage of burning (LSB), water absorption (WA), apparent porosity (AP), density (D) and tensile bending. Also were performed analyzes of X-ray diffraction (XRD) and scanning electron microscopy (SEM) of the samples fired. The formulations incorporating granite residue and/or ashes reached the required limits of water absorption according to NBR 15270-1 and NBR 15310 and tensile bending according to classical literature (SANTOS, 1989) necessary for the production of tiles and ceramic block for masonry sealing

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The production of waste from urban and industrial activities is one of the factors of environmental contamination and has aroused attention of the scientific community, in the sense of its reuse. On the other hand, the city of Salvador/Ba, with approximately 262 channels, responsible for storm water runoff, produces every year, by the intervention of cleaning and clearing channels, a significant volume of sediments (dredged mud), and thus an appropriate methodology for their final destination. This study aims to assess the influence of incorporation of these tailings in arrays of clay for production of interlocked block ceramic, also known as ceramic paver. All the raw materials from the metropolitan region of Salvador (RMS) were characterized by x-ray fluorescence, x-ray diffraction, thermal analysis (TG and TDA), particle size analysis and dilatometry. With the use of statistical experimental planning technique, ternary diagram was defined in the study region and the analyzed formulations. The specimens were prepared with dimensions of 60x20x5mm³, by uniaxial pressing of 30 MPa and after sintering at temperatures of 900°, 1000º and 1100ºC the technological properties were evaluated: linear shrinkage, water absorption, apparent porosity, apparent specifies mass, flexural rupture and module. For the uniaxial compression strength used cylindrical probe body with Ø 50 mm. The standard mass (MP) was prepared with 90% by weight of clay and 10% by weight of Channel sediment (SCP), not being verified significant variations in the properties of the final product. With the incorporation of 10% by weight of manganese residue (PFM) and 10% by weight of the Ceramic waste (RCB) in the mass default, in addition to adjusting the plasticity due to less waste clay content, provided increased linear firing shrinkage, due the significant concentration of K2O, forming liquid phase at low temperature, contributing to decreased porosity and mechanical resistance, being 92,5 MPa maximum compressive strength verified. After extract test leachate and soluble, the piece containing 10% of the PFM, was classified as non-hazardous and inert material according to NBR10004/04 ABNT. The results showed the feasibility on using waste, SCP, RCB and PFM clay mass, at temperatures above 900ºC, paver ceramic production, according to the specifications of the technical standards, so that to exceed the 10% of the PFM, it becomes imperative to conduct studies of environmental impacts

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Textile production has been considered as an activity of high environmental impact due to the generation of large volumes of waste water with high load of organic compounds and strongly colored effluents, toxic and difficult biodegradability. This thesis deals with obtaining porous alumina ceramic membranes for filtration of textile effluent in the removal of contaminants, mainly color and turbidity. Two types of alumina with different particle sizes as a basis for the preparation of formulation for mass production of ceramic samples and membranes. The technological properties of the samples were evaluated after using sintering conditions: 1,350ºC-2H, 1,450ºC-30M, 1,450ºC-2H, 1,475ºC-30M and 1,475ºC-2H. The sintered samples were characterized by XRD, XRF, AG, TG, DSC, DL, AA, MEA, RL, MRF-3P, SEM and Intrusion Porosimetry by Mercury. After the characterization, a standard membrane was selected with their respective sintering condition for the filterability tests. The effluent was provided by a local Textile Industry and characterized at the entry and exit of the treatment plant. A statistical analysis was used to study the effluent using the following parameters: pH, temperature, EC, SS, SD, oil and grease, turbidity, COD, DO, total phosphorus, chlorides, phenols, metals and fecal coliform. The filtered effluent was evaluated by using the same parameters. These results demonstrate that the feasibility of the use of porous alumina ceramic membranes for removing contaminants from textile effluent with improved average pore size of 0.4 micrometre (distribution range varying from 0,025 to 2.0 micrometre), with total porosity of 29.66%, and average percentages of color removal efficiency of 89.02%, 92.49% of SS, turbidity of 94.55%, metals 2.70% (manganese) to 71.52% (iron) according to each metal and COD removal of 72.80%

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Among the industries, those that produce ceramic porcelain for use in construction industry and oil, during the exploration and production period, play an important role in the production of waste. Much research has been carried out both by academia and the productive sector, sometimes reintroducing them in the same production line that generated them, sometimes in areas unrelated to their generation, as in the production of concrete and mortar for the construction, for example, but each one in an isolated way. In this research, the aim is to study the combined incorporation of the waste drill cuttings of oil well and the residue of the polishing of porcelain, generated in the final stage of finishing of this product in a clay matrix, for the production of red pottery, specifically bricks, ceramic blocks and tiles. The clay comes from the municipality of São Gonçalo, RN, the drilling waste is from the Natal basin, in Rio Grande do Norte, and the residue of the polishing proceeds from a ceramic porcelain of the State of Paraíba. For this purpose, we used a mixture of a plastic clay with a non-plastic, in a ratio of 50% each, settling formulations with the addition of these two residues in this clay matrix. In the formulations, both residues were incorporated with a minimum percentage of 2.5% and maximum of 12.5%, varying from 2.5% each, in each formulation, which the sum of the waste be no more than 15%. It should be noted that the residue of the polishing of ceramic porcelain is a IIa class (not inert). The materials were characterized by XRF, XRD, TG, DTA, laser granulometry and the plasticity index. The technological properties of water absorption, apparent porosity, linear shrinkage of burning, flexural tensile strength and bulk density were evaluated after the sintering of the pieces to 850 °C, 950 °C and 1050 °C, with a burning time of 3 hr, 3 hr and 30 minutes, and 3 hr and 50 minutes, respectively, with a heating rate of 10 °C/minute, for all formulations and landing of 30 minutes. To better understand the influence of each residue and temperature on the evaluated properties, we used the factorial planning and its surfaces of response for the interpretation of the results. It was found that the temperature has no statistical significance at a 95% of reliability level in flexural tensile strength and that it decreases the water absorption and the porosity, but increases the shrinkage and the bulk density. The results showed the feasibility of the desired incorporation, but adjusting the temperature to each product and formulation, and that the temperatures of 850 °C and 950 °C were the one that responded to the largest number of formulations

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Rio Grande do Norte State stands out as one great producer of structural clay of the brazilian northeastern. The Valley Assu ceramic tiles production stands out obtained from ilitics ball clays that abound in the region under study. Ceramics formulation and the design of experiments with mixture approach, has been applied for researchers, come as an important aid to decrease the number of experiments necessary to the optimization. In this context, the objective of this work is to evaluate the effects of the formulation, temperature and heating rate in the physical-mechanical properties of the red ceramic body used for roofing tile fabrication of the Valley Assu, using design of mixture experiments. Four clays samples used in two ceramics industry of the region were use as raw material and characterized by X-ray diffraction, chemical composition, differential thermal analysis (DTA), thermogravimetric analysis (TGA), particle size distribution analysis and plasticity techniques. Afterwards, they were defined initial molded bodies and made specimens were then prepared by uniaxial pressing at 25 MPa before firing at 850, 950 and 1050 ºC in a laboratory furnace, with heating rate in the proportions of 5, 10 e 15 ºC/min. The following tecnologicals properties were evaluated: linear firing shrinkage, water absorption and flexural strength. Results show that the temperature 1050 ºC and heating rate of 5 ºC/min was the best condition, therefore presented significance in all physical-mechanical properties. The model was accepted as valid based of the production of three new formulations with fractions mass diferents of the initial molded bodies and heated with temperature at 1050 ºC and heating rate of 5 ºC/min. Considering the formulation, temperature and heating rate as variables of the equations, another model was suggested, where from the aplication of design of experiments with mixtures was possible to get a best formulation, whose experimental error is the minor in relation to the too much formulations

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Nowadays, industries from all sectors have great concerns over the disposition of the residues generated along the productive process. This is not different in the mineral sector, as this generates great volumes of residues. It was verified that the kaolin improvement industry generates great volumes of residue basically constituted of kaolinite, muscovite mica and quartz, which are basic constitution elements to formularisations of ceramics masses to the production of covering of stoneware tiles type. This happens because the methodology applied to the improvement process is still very rudimentary, what causes a very low yield, only ¼ from all the material volume that enters the improvement process, in the end, is marketable. The disposal of this residue, in a general way, causes a very big negative environmental impact, what has justified the researches efforts aiming to find a rational solution to this problem. In this way, the intention of this present work is the utilization of this residue in the manufacture of products to high quality ceramics covering, stoneware tiles in an industrial scale. For this purpose, the influence of the addition of the residue to a standard ceramics mass used by a ceramics sector company, already established in the market, with the intention of verifying the possibility of use of this residue as the mass complementary raw material and even the possible partial or total substitution of one of the components of the mass for the raw material in evidence will be studied. To the accomplishment of this work, the kaolin improvement residue generated by an industry of exploitation and improvement of kaolin, located in the region of Equador-RN, in the levels 1,2,4,8, 16 and 32% will be added to the standard mass already used for the production of stoneware tiles. The raw materials used, kaolin residue and the standard mass, were characterized through DRX, FRX, DTA, TGA and dilatometry. After the sintering of the bodies of test, tests of water absorption, apparent porosity, post burning linear retraction, apparent specific mass and flexural strength (3 point bending) were realized to determinate the technological properties of these materials. The results show the studied residue can be considered raw material of great potential to the industry of floor and ceramics covering of the stoneware tiles type

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Micro and nanoparticulate systems as drug delivery carriers have achieved successful therapeutic use by enhancing efficacy and reducing toxicity of potent drugs. The improvement of pharmaceutical grade polymers has allowed the development of such therapeutic systems. Microencapsulation is a process in which very thin coatings of inert natural or synthetic polymeric materials are deposited around microsized particles of solids or around droplets. Products thus formed are known as microparticles. Xylan is a natural polymer abundantly found in nature. It is the most common hemicellulose, representing more than 60% of the polysaccharides existing in the cell walls of corn cobs, and is normally degraded by the bacterial enzymes present in the colon of the human body. Therefore, this polymer is an eligible material to produce colon-specific drug carriers. The aim of this study was to evaluate the technological potential of xylan for the development of colon delivery systems for the treatment of inflammatory bowel diseases. First, coacervation was evaluated as a feasible method to produce xylan microcapsules. Afterwards, interfacial cross-linking polymerization was studied as a method to produce microcapsules with hydrophilic core. Additionally, magnetic xylan-coated microcapsules were prepared in order to investigate the ability of producing gastroresistant systems. Besides, the influence of the external phase composition on the production and mean diameter of microcapsules produced by interfacial cross-linking polymerization was investigated. Also, technological properties of xylan were determined in order to predict its possible application in other pharmaceutical dosage forms

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The aim of this work was to perform the extraction and characterization of xylan from corn cobs and prepare xylan-based microcapsules. For that purpose, an alkaline extraction of xylan was carried out followed by the polymer characterization regarding its technological properties, such as angle of repose, Hausner factor, density, compressibility and compactability. Also, a low-cost and rapid analytical procedure to identify xylan by means of infrared spectroscopy was studied. Xylan was characterized as a yellowish fine powder with low density and poor flow properties. After the extraction and characterization of the polymer, xylan-based microcapsules were prepared by means of interfacial crosslinking polymerization and their characterization was performed in order to obtain gastroresistant multiparticulate systems. This work involved the most suitable parameters of the preparation of microcapsules as well as the study of the process, scale-up methodology and biological analysis. Magnetic nanoparticles were used as a model system to be encapsulated by the xylan microcapsules. According to the results, xylan-based microcapsules were shown to be resistant to several conditions found along the gastrointestinal tract and they were able to avoid the early degradation of the magnetic nanoparticles

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This scholarly work aims to investigate the feasibility and constitutionality of access to justice through the provision of full and free legal assistance by the Brazilian municipalities. Investigates the historical aspects of federalism in a global context, emphasizing the contributions left by American federalism. In the Brazilian context, emphasizing the importance of municipalities as federal entities and their outstanding characteristics, while addressing regional issues of federalism. Leanings to the more detailed analysis of the Brazilian municipalities, contextualizing its legal status, its independence and its constitutional powers. It is emphasized in the same way, the relevant transformations of Brazilian municipalities over the last twenty years of this Constitution of the Federative Republic of Brazil in 1988, especially the various constitutional amendments that affected the local autonomy and budgetary aspects, fiscal and skills, bringing significant changes to the municipalities. It is an approach to the concept of justice and deepening the studies on the fundamental right of access to justice in its various connotations. In this vein, it is a study on the legal advice provided in Brazil, especially the powers of the Public Defender of the States and Union, as well as the provision of such public service by Brazilian municipalities and its relevance to citizens in need. At this point, it deepens the relevance of the theme of this dissertation earning the implications of municipal performance in the provision of legal assistance provided to the needy, and the activity of the Municipal Attorney or legal counsel in conducting such a task and its implications for legal and procedural especially on the constitutionality or otherwise of the conduct of such public service, confronting the constitutional articles that are correlated with the subject. Within this context, evaluates the municipal legal assistance under the test of constitutionality, in particular the assistance given by the Executive, through the Municipal Attorney or specialized secretariats and that provided by the Legislature, although it only has the typical functions of legislating and control the municipal accounts, comes in a few municipalities in Brazil deploying sectors with the performance of legal services to the needy. At this point the thesis, one wonders if some important aspects of this activity such as political influence and patronage, very common in day-to-day municipal prosecutors and legal advisers, public employees or occupying commissioned positions within the municipal administrative structure in several municipalities throughout Brazil. Finally, there will be a conclusion as to the constitutionality of the service being done by presenting proposals and recommendations that may improve the municipal legal aid, allowing a constitutional backing to this important service is being provided in capital cities and municipalities throughout the length of Brazil

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This paper aims to discuss the conflicts of competence in environmental matters, as well as the legitimacy of the normative acts in the exercise of jurisdiction effected environmental management. For this work, addresses the issue of federalism, North American (dual) and German (cooperative), deepening its historical and theoretical fundamentals, as well as the influences on the evolution of the ideological matrix of Brazilian federalism. Distinguishes itself around the problem the theoretical and abstract discussion involving the constitutional division of powers, and the issue of his relationship with the vicissitudes in the embracement of environmental matters that invariably leads to mistakes in the exercise of jurisdiction environmental management. Its highlight the existence of a framework environmental law, embodying the principles themselves as well as a specific object of authority, which qualifies a different interpretation of the rules of constitutional powers as well as influencing the acting agent of government in managing the public good environment. The study represents an exploratory research as it investigates the depths of the institutes are in evidence not only with satisfying its practical outcome. For this to happen, explores bibliographical sources and identified by the science of law as more important, as the search for social-political boundary which takes the issue studied in their historical and contextual materiality, whose study is essential for a complete understanding of the topic . The dialectic that arguments have been constructed throughout the monograph, attempts to pass a critical way to expose the author's ideas, which considers as essential in the arrival of new questions

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The paper investigates the legal mechanisms used by the Legislature and the Executive to implement the constitutional principle of the teacher s minimum wage, which is proclaimed in the Constitution as a strategy of professional appreciation for this category. The text demonstrates that the legal mechanisms used to value the teacher were: the 1988 Constitution, the constitutional amendments to this Charter updated and modified the original text in relation to the matter, and finally, the Minimum Wage Law . Article nº 206 of 1988 s Federal Constitution established that basic education teachers, who work in public schools, would be entitled to a national minimum wage. Law nº 11.738/2008 ( Minimum Wage Law ) regulated the matter and made other determinations on the relationship between the State and the teachers such as the establishment of parameters for the distribution of the workload of teachers. Based on this law, since 2009 the minimum wage has been set annually by the Federal Government. However, state governments and municipalities throughout Brazil protested prescriptions contained in the Minimum Wage Law . In this context, some governors and mayors led the Supreme Court regarding the constitutionality of this law. The complainants considered that there was unconstitutional by the following: definition of the teacher s workday, which in the complainants point of view was competence of local governments; ensuring that teachers receive salaries tied to the minimum wage with retroactive effect; transformation of the minimum wage in basic salary, lack of sufficient budget in the states and municipalities to honor with the new values to be paid to teachers and, finally, determining workload for the teacher to perform other activities besides classroom activities. At the trial held at the STF the majority of Ministers rejected the claim and considered that the Minimum Wage Law , taken together, was constitutional. However, this decision did not alter the position of the managers or the interpretation of the ministers who agreed with the unconstitutionality of some aspects of the law. This means that one law can present differences in interpretation between ordinary people and among members of the Judiciary. The search showed the following conclusions: the law is not a definitive parameter of justice, because it is deeply linked to various interests; the development, implementation, and judgment of laws dealing with minimum wage of teaching are linked to historical and cultural aspects of society; the demand for enhancement of teacher and setting a minimum wage has only emerged in the late twentieth century, a fact explained in this work based on data that indicate the recent concern of Brazilian State with schooling a phenomenon typically Republican and with the professionalization of teaching emerging concern from the knowledge society; the Legislative and Executive search mechanism to implement the minimum wage of the teachers because of the contemporary need for professionalization of teaching

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The main goal of this work is to verify the presence of the principle of human dignity, determined by the Constitution of 1988, when Socio Educational Acts from the Statute of Children and adolescent were put in practice, focusing on the treatment designated to the youth whose acts were against the law in the city of Natal, as well as the difficulties to match the legal texts and its reality. It is common knowledge that the law for children and adolescent was based in the principle of human dignity, for its institutes say so. But would the Law match the practice of Socio Educational Acts? Or this law would be an example of good intentions that never left the paper and became reality? First there is an approach on the human dignity principle, with its definition and limitation, according to a theory about the theme. Afterwards it is made a connection between human rights and the principle of human dignity considering historical and social features, for the law is also a reflect of these transformations, we try to show the different laws the country had until today, concerning the children inflicted by poverty and those whose acts were against the law, since the rodas dos expostos, the phase of irregular situation, in which the children were arrested simply because they were beggars, until present time. The theory aspects are shown beside a field research made with the adolescent and staff from CEDUC/Natal, producing a critical view about the subject and showing some solutions for the problems found. At last, it is made a critical analyses of the problems detected on the field research, and, in some cases, a suggestion is given to change the reality

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A pesquisa analisa as possibilidades abertas pela exploração de petróleo na camada pré-sal, avaliando de que maneira a expansão do setor petrolífero poderá acelerar o crescimento econômico brasileiro e contribuir para novas estratégias de desenvolvimento. A hipótese inicial é que o Brasil enfrenta uma restrição estrutural de balanço de pagamentos, que poderá ser amenizada pela diminuição das importações de petróleo e derivados e pelo aumento do valor exportado no setor. Para avaliá-la são resgatados aspectos históricos e geopolíticos relacionados ao petróleo, assim como são tratadas as características microeconômicas dos recursos naturais não renováveis. Também se consideram questões de ordem macroeconômica, como a especialização produtiva da economia brasileira e sua inserção no comércio internacional, discutindo como o desenvolvimento da indústria petrolífera poderá afetá-las. Para tanto, a investigação fundamenta-se na teoria estruturalista e nos modelos de crescimento com ênfase na restrição externa. O trabalho examina ainda os casos da Rússia, Venezuela e México para avaliar a experiência de países exportadores de petróleo. Como contribuição, um modelo de crescimento é utilizado para realizar simulações acerca do Brasil, cobrindo o período 2013-2020 com a formulação de três cenários. A partir dos resultados discute-se que a necessidade de consecução das metas fiscal e de inflação pode desencadear políticas restritivas que limitam a utilização da folga fiscal e externa, oriundas do pré-sal, para induzir o crescimento. Conclui-se que um círculo virtuoso de desenvolvimento com mudança estrutural depende não apenas da modernização produtiva, mas também, e principalmente, da evolução político-institucional do país

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This works aims at investigating the effects of adding waste from RCBP-polyester button manufacturing to Portland cement concrete, particularly regarding its consistency and mechanic strength. The RCBP used came from a button factory located in Parnamirim, RN, Brazil. The waste was added to the concrete on different ratios: 5 %, 10 %, 15 % and 20 % of the total cement mass. A sample of concrete without the RCBP was used as reference, 1:1,33:2,45:0,50. For the mechanic strength test four samples were tested with different ages (3, 7 and 28 days old) and mixtures. Furthermore, a Slump Test was also conducted in order to verify the concrete s consistency. A tendency to a reduction in the compression resistance was noticed for all samples. For the samples with 5 % and 10 %, there was also an increase in the traction resistance during inflexion, regarding the reference concrete. In the microstructural analysis, the RBCP was observed to show an irregular and porous surface, thus explaining the consistency decrease

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This work presents results of field and laboratory tests using a Dynamic Cone Penetrometer, DCP. The tests were performed in order to evaluate the use of the equipment in sand for the control of bearing capacity of shallow foundations and fill compaction. For shallow foundations, the laboratory tests were conducted on sand placed in a metallic mould by the method of sand pluviation. Although the results show the inability to reproduce field conditions in the laboratory it was possible to verify the ability of the DCP to identify less resistant soil layers. The DCP tests for the analysis of compaction control were performed in a strong box with inside dimensions of 1,40 m x 1,40 m and 0,70 m in height. The soil layers were compacted with different densities though the use of a vibrating plate in order to obtain correlations between penetration index, DPI, and soil relative density. Other tests were also conducted to assess the influence of soil moisture on tests results. Among other findings, the results showed the great potential for the use of DCP to control the compaction of sand fills