Caracterização Microestrutural e Tribocorrosiva de Sistemas Metalocerâmicos Odontológicos do Tipo Ni-Cr/Porcelana E Ni-Cr/Ti/Porcelana

The partial fixed prosthodontics restoration is used to rehabilitate form and function of partial or total compromised teeth, having to remain permanently joined to remainder tooth. The most useful material on prosthodontics is the feldspar porcelain, commercialized as aluminosilicate powders. Dental porcelains are presented with limited mechanical properties to rehabilitate extensive spaces. The association with Ni-Cr metallic systems (metal-ceramic system) allows that the metallic substructure compensates the fragile porcelain nature, preserving the thermal insulation and aesthetics desirable, as well as reducing the possibility of cracking during matication efforts. Cohesive flaws by low mechanical strength connect the metallic substructure to the oral environment, characterized by a electrolytic solution (saliva), by aggressive temperature, pH cyclic changes and mechanical requests. This process results on ionic liberation that could promote allergic or inflammatory responses, and/or clinical degradation of ceramometal system. The aim of this study was to evaluate the presence of an intermediate titanium layer on the microscopic fracture behavior of porcelains on ceramometal systems. Plasma deposition of titanium films result in regular passivating oxide layers which act as barriers to protect the metallic substrate against the hazardous effects of corrosive saliva. Tribocorrosion tests were performed to simulate the oral environment and mechanical stress, making it possible the early detection of crack formation and growth on metal-ceramic systems, which estimate the adherence between the compounds of this system. Plain samples consisting of dental feldspar porcelain deposited either onto metallic substrates or titanium films were fired and characterized by scanning electron microscopy. The result showed that the titanium film improved the adherence of the system compared to conventional metal-ceramic interfaces, thus holding crack propagation

Formulação de bloco intertravado cerâmico com adição de resíduos urbanos e industriais

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

Desenvolvimento de filtros cerâmicos impregnados com nanopartículas de prata para desinfecção de água potável

Brazil has vast amounts of hydric resources, whose quality has been deteriorating due to pollutant dumping. Household waste disposal is one of the main sources of water pollution, stimulating bacteria proliferation and introducing microorganisms, including those from fecal matter. Conventional water disinfection methods are a solution, but on the downside, they lead to the formation byproducts hazardous to human health. In this study, aiming to develop bactericidal filters for the disinfection of drinking water; silver nanoparticles were deposited on alumina foams through three routes: sputtering DC, dip coating and in situ chemical reduction of silver nitrate. The depositions were characterized through X-ray diffraction, scanning electron microscopy and EDS element mapping. The influence of the depositions on permeability and mechanical properties of the ceramic foams was assessed and, in sequence, a preliminary antibacterial efficiency analysis was carried out. Characterization results indicate that the chemical reduction routes were efficient in depositing homogeneously distributed silver particles and that the concentration of the metallic precursor salt affects size and morphology of the particles. The antibacterial efficiency analysis indicates that the chemical reduction filters have potential for water disinfection

Biodegradação de hidrocarbonetos aromáticos policíclicos: prospecção metagenômica e modelagem computacional 3-D de proteínas

Knowledge of the native prokaryotes in hazardous locations favors the application of biotechnology for bioremediation. Independent strategies for cultivation and metagenomics contribute to further microbiological knowledge, enabling studies with non-cultivable about the "native microbiological status and its potential role in bioremediation, for example, of polycyclic aromatic hydrocarbons (HPA's). Considering the biome mangrove interface fragile and critical bordering the ocean, this study characterizes the native microbiota mangrove potential biodegradability of HPA's using a biomarker for molecular detection and assessment of bacterial diversity by PCR in areas under the influence of oil companies in the Basin Petroleum Geology Potiguar (BPP). We chose PcaF, a metabolic enzyme, to be the molecular biomarker in a PCR-DGGE detection of prokaryotes that degrade HPA s. The PCR-DGGE fingerprints obtained from Paracuru-CE, Fortim-CE and Areia Branca-RN samples revealed the occurrence of fluctuations of microbial communities according to the sampling periods and in response to the impact of oil. In the analysis of microbial communities interference of the oil industry, in Areia Branca-RN and Paracuru-CE was observed that oil is a determinant of microbial diversity. Fortim-CE probably has no direct influence with the oil activity. In order to obtain data for better understanding the transport and biodegradation of HPA's, there were conducted in silico studies with modeling and simulation from obtaining 3-D models of proteins involved in the degradation of phenanthrene in the transport of HPA's and also getting the 3-D model of the enzyme PcaF used as molecular marker in this study. Were realized docking studies with substrates and products to a better understanding about the transport mechanism and catalysis of HPA s

Responsabilidade civil como função social na distribuição e revenda de combustível face ao direito do consumidor e ao meio ambiente

The civil liability of the distribution and retail fuel stems from the fact business activity developed to be high risk and can be said as risk inherent or latent danger that has predictability and normality characterized by placing the consumer in a position of vulnerability, such as the environment, both public policies defined and constitutional protection. Consumer protection as a fundamental right and the environment as the primacy of social order aims the welfare and social justice, as inserted right to the third dimension, are guarded by the State when it creates operational standards through public policies and indirectly intervenes in the economic order. This intervention is due to consumer protection and the environment are economic order principles, founded on free initiative and free competition, ensuring everyone a dignified existence which underlies the irradiation of fundamental rights in private initiative, before the commercial evaluation, mass consumption, the emergence of new technologies that link consumers to the environment before the protection of life, health and safety and ensuring a better quality of life for present and future generations. To repair this damage and the right to information are provided as fundamental rights that put the person at the epicenter of the relations and collective interest stands out against individual interests that to be done need public-private partnership. In such a way that the used methodology was an analysis of documents correlating them with bibliographic sources whose goals are to recognize the civil responsibility as limit to subjective right, having to develop a social function where guilt and risk grow distant and the damage is configured as a consequence of inherent risk, requiring the State interventional postures in fulfilling its public policy; prevailing in these risky activities the solidarity of those involved in the chain of production and socialization of damage forward those are provided directly of products of hazardous nature that put in a position of vulnerability the environment and the consumer

Desenvolvimento de um sistema de automação para uma planta de inertização de resíduos por plasma

The traditional processes for treatment of hazardous waste are questionable for it generates other wastes that adversely affect people s health. As an attempt to minimize these problems, it was developed a system for treatment of hazardous waste by thermal plasma, a more appropriate technology since it produces high temperatures, preventing the formation of toxic pollutants to human beings. The present work brings out a solution of automation for this plant. The system has local and remote monitoring resources to ensure the operators security as well as the process itself. A special attention was given to the control of the main reactor temperature of the plant as it is the place where the main processing occurs and because it presents a complex mathematical model. To this, it was employed cascaded controls based on Fuzzy logic. A process computer, with a particular man-machine interface (MMI), provides information and controls of the plant to the operator, including by Internet. A compact PLC module is in charge of the central element of management automation and plant control which receives information from sensors, and sends it to the MMI

Análise dos Processos de Flotação e Oxidação Avançada para o Tratamento de Efluente Modelo da Indústria do Petróleo

The generation of wastes in most industrial process is inevitable. In the petroleum industry, one of the greatest problems for the environment is the huge amount of produced water generated in the oil fields. This wastewater is a complex mixture and present great amounts. These effluents can be hazardous to the environmental without adequate treatment. This research is focused in the analysis of the efficiencies of the flotation and photo-oxidation processes to remove and decompose the organic compounds present in the produced water. A series of surfactants derivated from the laurilic alcohol was utilized in the flotation to promote the separation. The experiments have been performed with a synthetic wastewater, carefully prepared with xylene. The experimental data obtained using flotation presented a first order kinetic, identified by the quality of the linear data fitting. The best conditions were found at 0.029 g.L-1 for the surfactant EO 7, 0.05 g.L-1 for EO 8, 0.07 g.L-1 for EO 9, 0.045 g.L-1 for EO 10 and 0.08 g.L-1 for EO 23 with the following estimated kinetic constants: 0.1765, 0.1325, 0.1210, 0.1531 and 0.1699 min-1, respectively. For the series studied, the most suitable surfactant was the EO 7 due to the lower reagent onsumption, higher separation rate constant and higher removal efficiency of xylene in the aqueous phase (98%). Similarly to the flotation, the photo-Fenton process shows to be efficient for degradation of xylene and promoting the mineralization of the organic charge around 90% and 100% in 90 min

Caracterização do lodo de lagoa anaeróbia tratando resíduos esgotados de tanques sépticos e fossas com vistas ao aproveitamento

The sludge generated in stabilization ponds can be designed for various purposes, among them we mention agricultural use, recovery of degraded areas and civil construction. The choice of these alternatives should be made based on qualitative and quantitative characteristics of the sludge. In this context, this study characterized the digested sludge from an anaerobic lagoon in Cidade do Natal/RN, which deals exclusively with residues of depleted septic tanks and pits. The sludge showed levels of macro and micronutrients that confirm its potential for agriculture, with 139.49 g.kg -1 organic matter, 15.40 g.kg-1 nitrogen and metal concentrations below those required by Resolution No. 375/06 of CONAMA, besides the absence of fecal coliform and less than 0.15 viable helminthes eggs/g, on average. The particle size distribution showed that most of the particles have a diameter similar to the sand, allowing the replacement of this input, for example. Analysis of the leachate and of the sludge solubilized classified as non-inert and non-hazardous according to NBR 10.004/04. The volume produced in three years of operation by the pond was 1903.50m³, equivalent to approximately 400 kg of dry sludge. Overall, the concentrations of the parameters were similar to literature, although none of them addresses sludge anaerobic pond treating sewer from septic tanks and pits.The sludgepresents technical feasibility to various types of use, however the cost of dewatering and especially with transport can derail it. It needs to be made a more thorough study of the costs to prove its economic viability

Análise dos Processos de Flotação e Oxidação Avançada para o Tratamento de Efluente Modelo da Indústria do Petróleo

The generation of wastes in most industrial process is inevitable. In the petroleum industry, one of the greatest problems for the environment is the huge amount of produced water generated in the oil fields. This wastewater is a complex mixture and present great amounts. These effluents can be hazardous to the environmental without adequate treatment. This research is focused in the analysis of the efficiencies of the flotation and photo-oxidation processes to remove and decompose the organic compounds present in the produced water. A series of surfactants derivated from the laurilic alcohol was utilized in the flotation to promote the separation. The experiments have been performed with a synthetic wastewater, carefully prepared with xylene. The experimental data obtained using flotation presented a first order kinetic, identified by the quality of the linear data fitting. The best conditions were found at 0.029 g.L-1 for the surfactant EO 7, 0.05 g.L-1 for EO 8, 0.07 g.L-1 for EO 9, 0.045 g.L-1 for EO 10 and 0.08 g.L-1 for EO 23 with the following estimated kinetic constants: 0.1765, 0.1325, 0.1210, 0.1531 and 0.1699 min-1, respectively. For the series studied, the most suitablesurfactant was the EO 7 due to the lower reagent consumption, higher separation rate constant and higher removal efficiency of xylene in the aqueous phase (98%). Similarly to the flotation, the photo-Fenton process shows to be efficient for degradation of xylene and promoting the mineralization of the organic charge around 90% and 100% in 90 min

Avaliação da remoção de hidrocarbonetos aromáticos (BTEX) em águas utilizando materiais nanoestruturados do tipo Ti-MCM-41

Volatile Organic Compounds are pollutants coming mainly from activities that use fossil fuels. Within this class are the BTEX (benzene, toluene, ethylbenzene and xylenes) compounds that are considered hazardous. Among the various existing techniques for degradation of pollutants, there is advanced oxidation using H2O2 generating hidoxil radical ( OH). In this work, the mesoporous material of MCM-41 was synthesized by hydrothermal method and then was used as support, the impregnation of titanium by the method of synthesis with excess solvent to obtain the catalyst Ti-MCM-41. The catalyst was used in the reaction catalyzed removal of BTEX in water using H2O2 as oxidant. The materials were characterized by: XRD, TG/DTG, FTIR, nitrogen adsorption-desorption and FRX-EDX, in order to verify the method of impregnation of the mesoporous titanium support was effective. Catalytic tests were carried out in reactors of 20 mL containing BTEX (100.0 μg/L), H2O2 (2.0 M) and Ti-MCM-41 (2.0 g/L) in acid medium. The reaction occurred for 5 h at 60 °C and analysis were performed by gas chromatography with photoionization detector and static headspace sampler. The characterizations have proven the effectiveness of the synthesis method used and the incorporation of titanium lt in the support. The catalytic tests showed satisfactory results with conversion of more than 95 % for the studied compounds, where the catalyst 48% Ti-MCM-41 showed a higher removal efficiency of the compounds under study

Tratamento de borra de petróleo com sistemas microemulsionados

During the storage of oil, sludge is formed in the bottoms of tanks, due to decantation, since the sludge is composed of a large quantity of oil (heavy petroleum fractions), water and solids. The oil sludge is a complex viscous mixture which is considered as a hazardous waste. It is then necessary to develop methods and technologies that optimize the cleaning process, oil extraction and applications in industry. Therefore, this study aimed to determine the composition of the oil sludge, to obtain and characterize microemulsion systems (MES), and to study their applications in the treatment of sludge. In this context, the Soxhlet extraction of crude oil sludge and aged sludge was carried out, and allowing to quantify the oil (43.9 % and 84.7 % - 13 ºAPI), water (38.7 % and 9.15 %) and solid (17.3 % and 6.15 %) contents, respectively. The residues were characterized using the techniques of X-ray fluorescence (XRF), Xray diffraction (XRD) and transmission Infrared (FT-IR). The XRF technique determined the presence of iron and sulfur in higher proportions, confirming by XRD the presence of the following minerals: Pyrite (FeS2), Pyrrhotite (FeS) and Magnetite (Fe3O4). The FT-IR showed the presence of heavy oil fractions. In parallel, twelve MES were prepared, combining the following constituents: two nonionic surfactants (Unitol L90 and Renex 110 - S), three cosurfactants (butanol, sec-butanol and isoamyl alcohol - C), three aqueous phase (tap water - ADT, acidic solution 6 % HCl, and saline solution - 3.5 % NaCl - AP) and an oil phase (kerosene - OP). From the obtained systems, a common point was chosen belonging to the microemulsion region (25 % [C+S] 5 % OP and AP 70 %), which was characterized at room temperature (25°C) by viscosity (Haake Rheometer Mars), particle diameter (Zeta Plus) and thermal stability. Mixtures with this composition were applied to oil sludge solubilization under agitation at a ratio of 1:4, by varying time and temperature. The efficiencies of solubilization were obtained excluding the solids, which ranged between 73.5 % and 95 %. Thus, two particular systems were selected for use in storage tanks, with efficiencies of oil sludge solubilization over 90 %, which proved the effectiveness of the MES. The factorial design delimited within the domain showed how the MES constituents affect the solubilization of aged oil sludge, as predictive models. The MES A was chosen as the best system, which solubilized a high amount of aged crude oil sludge (~ 151.7 g / L per MES)

Eficiência de extração de cobre e níquel utilizando sistemas microemulsionados bifásicos e trifásicos

The environmental impact due to the improper disposal of metal-bearing industrial effluents imposes the need of wastewater treatment, since heavy metals are nonbiodegradable and hazardous substances that may cause undesirable effects to humans and the environment. The use of microemulsion systems for the extraction of metal ions from wastewaters is effective when it occurs in a Winsor II (WII) domain, where a microemulsion phase is in equilibrium with an aqueous phase in excess. However, the microemulsion phase formed in this system has a higher amount of active matter when compared to a WIII system (microemulsion in equilibrium with aqueous and oil phases both in excess). This was the reason to develop a comparative study to evaluate the efficiency of two-phases and three-phases microemulsion systems (WII and WIII) in the extraction of Cu+2 and Ni+2 from aqueous solutions. The systems were composed by: saponified coconut oil (SCO) as surfactant, n-Butanol as cosurfactant, kerosene as oil phase, and synthetic solutions of CuSO4.5H2O and NiSO4.6H2O, with 2 wt.% NaCl, as aqueous phase. Pseudoternary phase diagrams were obtained and the systems were characterized by using surface tension measurements, particle size determination and scanning electron microscopy (SEM). The concentrations of metal ions before and after extraction were determined by atomic absorption spectrometry. The extraction study of Cu+2 and Ni+2 in the WIII domain contributed to a better understanding of microemulsion extraction, elucidating the various behaviors presented in the literature for these systems. Furthermore, since WIII systems presented high extraction efficiencies, similar to the ones presented by Winsor II systems, they represented an economic and technological advantage in heavy metal extraction due to a small amount of surfactant and cosurfactant used in the process and also due to the formation of a reduced volume of aqueous phase, with high concentration of metal. Considering the reextraction process, it was observed that WIII system is more effective because it is performed in the oil phase, unlike reextraction in WII, which is performed in the aqueous phase. The presence of the metalsurfactant complex in the oil phase makes possible to regenerate only the surfactant present in the organic phase, and not all the surfactant in the process, as in WII system. This fact allows the reuse of the microemulsion phase in a new extraction process, reducing the costs with surfactant regeneration