Estudo de formulação de massa para aplicação em placas cerâmicas

The sector of civil construction is strongly related to the red ceramic industry. This sector uses clay as raw material for manufacturing of various products such as ceramic plates. In this study, two types of clay called clay 1 and clay 2 were collected on deposit in Ielmo Marinho city (RN) and then characterized by thermogravimetric analysis (TG/DTG), differential thermal analysis (DTA), X-ray diffraction (XRD), X-ray fluorescence (XRF), rational analysis and particle size distribution and dilatometric analyses. Ceramic plates were manufactured by uniaxial pressing and by extrusion. The plates obtained by pressing were produced from the four formulations called 1, 2, 3 and 4, which presented, respectively, the following proportions by mass: 66.5% clay 1 and 33.5% clay 2, 50% clay 1 and 50% clay 2, 33.5% clay 1 and 66.5% clay 2, 25% clay 1 and 75% clay 2. After firing at 850, 950 and 1050 °C with heating rate of 10 °C/min and soaking time of 30 minutes, the following technological properties were determined: linear firing shrinkage, water absorption, apparent porosity, apparent specific mass and tensile strength (3 points). The formulation containing 25% clay 1 produced plates with most satisfactory results of water absorption and mechanical resistance, because of that it was chosen for manufacturing plates by extrusion. A single firing cycle was established for these plates, which took place as follow: heating rate of 2 °C/min up to 600 ºC with soaking time of 60 minutes, followed by heating using the same rate up to 1050 ºC with soaking time of 30 minutes. After this cycle, the same technological properties investigated in the plates obtained by pressing were determined. The results indicate (according to NRB 13818/1997) that the plates obtained by pressing from the mixture containing 25 wt% clay 1, after firing at 1050 °C, reach the specifications for semi-porous coating (BIIb). On the other hand, the plates obtained by extrusion were classified as semi-stoneware (group AIIa)

Validação de uma metodologia de ensaio de resistência ao cisalhamento para avaliação da aderência de interfaces revestimento metálico-bainha de cimento aplicada a poços de petróleo

Improving the adherence between oilwell metallic casing and cement sheath potentially decrease the number of corrective actions present/y necessary for Northeastern wells submitted to steam injection. In addition to the direct costs involved in the corrective operations, the economic impact of the failure of the primary cementing aIso includes the loss in the production of the well. The adherence between casing and cement is current/y evaluated by a simple shear tests non standardized by the American Petroleum Institute (API). Therefore, the objective of the present is to propose and evaluate a standardized method to assess the adherence of oilwell metallic casing to cement sheath. To that end, a section of a cemented oilwell was simulated and used to test the effect of different parameters on the shear stress of the system. Surface roughness and different cement compositions submitted or not to thermal cycling were evaluated. The results revealed that the test geometry and parameters proposed yielded different values for the shear stress of the system, corresponding to different adherent conditions between metallic casing and cement sheath

Aplicação de ultrassons no deslocamento de petróleo em meio poroso

The objective of this study was to evaluate the displacement of petroleum/diesel solutions, at different concentrations, observing the effect of ultrasonic vibrations in fluids present in porous media to obtain an increase in oil production. The bubbles produced by ultrasound implode asymmetrically in the rock, generating liquid jets with high speed, displacing the oil present in porous media. The oil/diesel solutions were prepared with concentrations ranging from 20 g/L to 720 g/L in oil in relation to diesel and its viscosities were obtained in a Brookfield Rheometer RS2000, with temperature ranging from 25 to 55 °C. After, calculations were performed to obtain the activation energy data for oil/diesel solutions. For oil recovery experiments, cylindrical samples of porous rock (core samples), with resin around the perimeter and its two circular bases free to allow the passage of fluids, were first saturated with 2% KCl solution and after with oil solutions. The results of oil extraction were satisfactory for all studied solutions, being obtained up to 68% partial displacement with saline solution injection. The ultrasound system was used after saline injection, increasing oil displacement, with oil extractions ranging from 63% to 79%. During the experiments, it was observed the warming of core samples, helping to reduce the viscosity of more concentrated systems, and consequently enhancing the percentage of advanced recovery for all studied solutions

Uso da palha de carnaúba em revestimento de dutos

In this work, the plant species Copernicia prunifera (Miller) H. E. Moore (carnauba), naturally occurring which prevails in the northeast region of Brazil was the subject of studies aiming its use as external coating of pipelines used in petroleum industry. The part of the plant worked were the leaves, also called straw, which were coated with resinous material. For this purpose, it was necessary to evaluate the effectiveness of the use of acrylic resins in the straw carnauba coating. The properties of the untreated carnauba straw and chemically treated with sodium hydroxide, hexane and carbon tetrachloride were investigated by ATRFTIR, SEM and thermal analysis. The first two techniques showed that treatment with solvents has caused major changes in the straw surface, while the thermal analysis indicated that the sodium hydroxide caused variations in thermal stability of straw constituents. Water absorption measurements showed that treatments have accelerated the absorption process and the reduction of contact angle values for treated samples with solvents indicated higher hidrophilicity of straw. The tensile tests showed lower values of elastic modulus and tensile strength for treated samples. Furthermore, coatings using pure commercial resins A and B as well as the formulations with clay were applied in straw and they were examined once again through thermal analysis, water absorption measurements, contact angle and mechanical tests. To analyze the effect of heat ageing, samples were subjected to tensile tests again in order to assess its resistance. The results showed that the resins/clay formulations increased thermal stability of straw, they promoted a good impermeabilization and caused significant decrease in the values of elastic modulus and tensile strength. Evaluating the ageing effect on the mechanical properties, it has been showed good recovery to the coated straw with the formulations A 60 and A 80% in modulus and tensile strength values and elongation at break values have remained very close. It is thus concluded that the carnauba straw can be used as a coating of pipelines with significant cost savings, since there is no need for pretreatment for its use and shows itself as a viable biotechnology alternative, contributing to the quality of coatings material and environment preservation.

Entendendo as propriedades do arenito Botucatu e sua utilização como meio poroso para estudos envolvendo o deslocamento de fluidos poliméricos

The development of products whose purpose is to promote blockages in high permeability zones as well as to control the hydrate or scale formation also needs some tests in porous media before using the product in the field, where attempts and unavoidable operational errors costs would able to derail any projects. The aim of this study was to analyze and compare the Botucatu and Berea sandstones properties, involving problems related to loss permeability. It was observed that even cores of Berea, without expansible clays in their composition had their permeability reduced, as soon as the salinity of brine reached a lower limit. As expected, the same happened with the Botucatu sandstone samples, however, in this case, the sensitivity to low salinity was more pronounced. In a second phase, the research was focused on the Botucatu Sandstone behavior front of dilute polymer solutions injection, checking the main relationships between the Rock / Fluid interactions, considering the Mobility Reduction, Resistance and Residual Resistance Factors, as well as adsorption/desorption processes of these polymers, and the polymer molecules average size and porous sandstone average size ratio. The results for both phases showed a real feasibility of using the Botucatu sandstone in laboratory tests whose objective is the displacement of fluids through porous media

Simulação de Fluxo no Meio Poroso Utilizando o Fluent

The complexity of the Phenomenon of fluid flow in porous way causes a difficulty in its explicit description. Different in the cases where the flow is given through a pipe, where it is possible to measure the length and diameter of the pipe and to determine their ability to flow as a function of pressure, which is a complicated task in porous way. However, we try to approach clearly the equations used to conjecture the behavior of fluid flow in porous way. We made use of the Gambit to create a fractal geometry with the fluent we give the contour´s conditions we would want to analyze the data. The triangular mesh was created; it makes interactions with the discs of different rays, as barriers putted in the geometry. This work presents the results of a simulation with a flow of viscous fluids (oilliquid). The oil flows in a porous way constructed in 2D. The behavior evaluation of the fluid flow inside the porous way was realized with graphics, images and numerical results used for different datas analysis. The study was aimed in relation at the behavior of permeability (k) for different fractal dimensions. Taking into account the preservation of porosity and increasing the fractal distribution of the discs. The results showed that k decreases when we increase the numbers of discs, although the porosity is the same for all generations of the first simulation, in other words, the permeability decreases when we increase the fractality. Well, there are strong turbulence in the flow each time we increase the number of discs and this hinders the passage of the same to the exit. These results permitted to put in evidence how the permeability (k) is affected in a porous way with obstacles distributed in a diversified form. We also note that k decreases when we increase the pressure variation (P) within geometry. So, in front of the results and the absence of bibliographic subsidies about other theories, the work realized here can possibly by considered the unpublished form to explain and reflect on how the permeability is changed when increasing the fractal dimension in a porous way

Avaliação da influência de cinza da casca de arroz em cimentos para poços de petróleo submetidos à injeção de vapor

Reservoirs that present highly viscous oils require methods to aid in their recovery to the surface. The elev ated oil viscosity hinders its flow through porous media and conventional recovery methods have not obtained significant efficiency. As such, the injection of steam into the reservoir through an injection well has been the most widely used method of therma l recovery, for it allows elevated volumes of recovery due to the viscosity reduction of the oil, facilitating the oil’s mobility within the rock formation and consequently into the production well where it will be exploited. On the other hand, the injecti on of vapor not only affects the fluids found in the rock pores, but the entire structure that composes the well where it is injected due to the high temperatures used in the process. This temperature increment is conducted to the cement, found in the annu lus, responsible for the isolation of the well and the well casing. Temperatures above 110 ̊C create new fazes rich in calcium in the cement matrix, resulting in the reduction of its permeability and the consequential phenomenon of mechanical resistance ret rogression. These alterations generate faults in the cement, reducing the well’s hydraulic isolation, creating insecurity in the operations in which the well will be submitted as well as the reduction of its economic life span. As a way of reducing this re trograde effect, this study has the objective of evaluating the incorporation of rice husk ash as a mineral additive substitute of silica flour , commercially utilized as a source of silica to reduce the CaO/SiO 2 ratio in the cement pastes submitted to high temperatures in thermal recovery. Cement pastes were formulated containing 20 and 30% levels of ash, apart from the basic paste (water + cement) and a reference paste (water + cement + 40% silica flour) for comparison purposes. The tests were executed th rough compression resistance tests, X - Ray diffraction (XRD) techniques, thermogravimetry (TG), scanning electron microscopy (SEM) and chemical anal ysis BY X - ray fluorescence (EDS) on the pastes submitted to cure at low temperatures (45 ̊C) for 28 days following a cure at 280 ̊C and a pressure of 2,000 PSI for 3 days, simulating vapor injection. The results obtained show that the paste containing 30% r ice shell ash is satisfactory, obtaining mechanical resistance desired and equivalent to that of the paste containing 40% silica flour, since the products obtained were hydrated with low CaO/SiO 2 ratio, like the Tobermorita and Xonotlita fases, proving its applicability in well subject to vapor injection.

Fluxo de fluído através de um meio poroso fractal desordenado. Análise das tensões de cisalhamento e efeito de escala na estimativa das forças viscosas

In this work we have investigated some aspects of the two-dimensional flow of a viscous Newtonian fluid through a disordered porous medium modeled by a random fractal system similar to the Sierpinski carpet. This fractal is formed by obstacles of various sizes, whose distribution function follows a power law. They are randomly disposed in a rectangular channel. The velocity field and other details of fluid dynamics are obtained by solving numerically of the Navier-Stokes and continuity equations at the pore level, where occurs actually the flow of fluids in porous media. The results of numerical simulations allowed us to analyze the distribution of shear stresses developed in the solid-fluid interfaces, and find algebraic relations between the viscous forces or of friction with the geometric parameters of the model, including its fractal dimension. Based on the numerical results, we proposed scaling relations involving the relevant parameters of the phenomenon, allowing quantifying the fractions of these forces with respect to size classes of obstacles. Finally, it was also possible to make inferences about the fluctuations in the form of the distribution of viscous stresses developed on the surface of obstacles.

Revestimento decorativo monocamada pigmentado, com resíduo de vidro temperado, para aplicação em fachadas

Although efficient from a technical point of view, mortar layers that make up the traditional masonry coating (slurry mortar, plaster and plaster) have to be in contradiction with the new construction technologies and more efficient methods of consumption and work rationalization. From an environmental point of view, the recovery of waste into new composites for the building has been a growing strand of studies in the scientific community, may prove to be a cost-effective solution in some cases. Thus, this research proposes the development of a mortar Decorative Coating Monolayer (RDM), for use in facades, produced on site, incorporating tempered glass waste (RVT) in the cement matrix, as a partial substitute for aggregate. Therefore, we adopted the binder respect / aggregate of 1: 6 (by volume), consistency index 250mm ± 20, sand substitution levels of glass waste 20%, 50% and 80% and relative water / cement varied in many traits. Two additives were used, a polymer, styrene-butadiene-based, and other chemical, besides mineral and silica fume inorganic pigment in colors red, yellow and blue. Mechanical tests were carried out on fresh pasta and hardened, as well as for the applied coating on masonry, so as to demonstrate the feasibility of the material. In addition, it verified the adequacy of the RDM built environment by means of thermal tests. The results demonstrated the feasibility of the proposed RDM with significantly higher values when compared to norms, especially the dash-added replacement content of 20% and addition of pigment in red. Therefore, the study shows the scientific community as an incentive to the use of technological innovations in construction, increasing the range of alternatives available for housing production, with the proposition of a material that achieves the desired functionality and obtain environmental gain, and may be adopted on construction sites as an alternative industrialized mortars.

Análise e avaliação dos elementos de penetração no solo de equipamentos rodoviários após revestimento

The main objective is to analyze the abrasive wear resistance to the low stress of the elements that make up the organs of road machinery that are exposed directly to contact with abrasives. These samples were analyzed after these elements are coated superficially by the process of welding electrode coated with (SAER) and the manual process of coating type LVOF thermal spraying. As well, is to provide suggestions for a better recovery and return of these elements, which are reducing costs and avoiding downtime in the fronts of service. The samples were made from a substrate of carbon ABNT 1045 tempered steel, following the same specifications and composition of metals and alloys of constituents was followed the standard governing the dimensions of these samples and in accordance with the corresponding size. The results were evaluated by testing the hardness, abrasion resistance to wear by the low stress and the loss of volume involving the microstructure of coatings analyzed

Avaliação da potencialidade dos resíduos de gesso de revestimento incorporados em formulações de massas cerâmicas

In building, during the implementation process of major or even minor works, there is a considerable waste of plaster in the steps of coating, making it is a negative factor because of the loss of these processes constructive remains incorporated into buildings, as component, whose final dimensions are higher than those projected. Another negative factor is the disposal of waste gypsum in inappropriate places, thus contributing to the degradation of environmental quality, due to the leaching of this waste and may trigger the formation of sulfuric acid. Therefore, based on this picture, processing and reuse of waste coating, combined with the ceramics industry, which is a strong potential in the reuse of certain types of waste, promote mutual benefits. Thus the overall objective of this work is to conduct a search with scientific and technological aspects, to determine the effect of the incorporation of the residue of plaster for coating, from the building, the formulation of bodies for red ceramic. The residue of plaster coating was collected and characterized. They were also selected raw materials of two ceramic poles of the state of Rio Grande do Norte and formulations have been made with the intention of obtaining those with the best physical and mechanical properties, the residue was added the percentage of 5%, 10%, 15%, 20%, 25% and 30%, in the best formulation of ceramic industry 1 and, according the properties analyses, 5%, 10% and 15% as the best results of ceramic industry 2. The samples were sintered at temperatures of 850 ºC, 950 °C and 1050 °C, the heating rate of 5 ºC / min with isotherm of two hours. They were submitted to testing technology, such as lineal shrinkage, water absorption, apparent porosity, apparent density and bending resistence. The residue incorporation best results in the formulations of mass in red ceramic, were observed between the temperatures of 850 ºC and 950 ºC, in those formulations that have illite clays and medium plastic in their composition, in the range of 0% to 15% residue incorporated

Estudo do resíduo fosfogesso na formulação de uma pasta para revestimento interno de edifícios

Universidade Federal do Rio Grande do Norte

Influência da adição de resíduo de caulim nas propriedades tecnológicas de uma massa padrão de porcelanato produzido em escala industrial

VARELA, M. L. et al. Influência da adição de resíduo de caulim nas propriedades tecnológicas de uma massa padrão de porcelanato produzido em escala industrial. Cerâmica, v.55, n.334 p.209-215. 2009.ISSN 0366-6913.Disponível em: . Acesso em: 06 out. 2010.

Nitretação a plasma: fundamentos e aplicações

A nitretação é uma técnica de tratamento de superfície utilizada para endurecer superfícies de metais, principalmente de aços. O uso do plasma para auxiliar esta técnica vem crescendo nos últimos anos. Pelo fato desta técnica utilizar o plasma como fonte energética e este possuir uma vasta aplicação em outras técnicas para processamento de materiais, enobrece ainda mais a leitura do presente livro. Ele apresenta uma revisão da descarga elétrica em gases levando o leitor a refletir, multidisciplinarmente, sobre possibilidades de aplicação da mesma. Apresenta a técnica de nitretação iônica sob o aspecto histórico, científico, tecnológico, operacional e econômico e, finalmente, faz uma revisão das novas técnicas de endurecimento superficial assim como as técnicas convencionais de nitretação

Adequação bioclimática para os espaços urbanos abertos do centro de Fortaleza, CE

This research presents a study investigating the correlation between the environmental-physycal charcateristics of cities and the formation of its micro-climates. The study was conducted in the central area of Fortaleza characterized as a stable and consolidated area, where the city originated and currently faces serious problems in its urban dynamics. The points of measurements were determined by the elaboration and analysis of topography maps, height of buildings, land use, type of surface coating and vegetation, following the methodology of Katzschner (1997). A zoning map was then determined, according to common morphological characteristics of the 12 measurement points, which were based on a set of Romero s (2001) bioclimatic criteria. Air measurements, temperature, humidity, intensity and direction of winds were made in transect form in two different circuits in the study area, with six points of data collection in each area, in three different times: 6:00 am, 1:00pm and 7:00pm, during two periods of the year: August 2008 and March 2009. The results verified the influence of different environmental-physical types in the behavior of the climatic variables that were collected. A verticalização tão condenada em algumas situações se bem equilibrada e controlada pode reduzir as temperaturas do ar através do sombreamento dos espaços urbanos e possibilidade de maior permeabilidade a ventilação natural. The highest average air temperature and lower humidity were recorded at the point I at all times. This situation may have been in result of the high density, poor vegetation and extended paving of the ground. According to the results, it s clear the positive influence vegetation has on easing air temperature. Another indicator observed that areas with a greater variation in building heights tend to present decreased average air temperature. High rise structure, planned in accordance to urban air quality parameters, can reduce air temperatures by the shading of urban spaces and the possibility of greater penetration of natural ventilation