Desenvolvimento de um sistema misto de pasta à base de geopolímero e cimento portland para correção de perda de circulação

The materials engineering includes processes and products involving several areas of engineering, allowing them to prepare materials that fulfill the needs of various new products. In this case, this work aims to study a system composed of cement paste and geopolymers, which can contribute to solving an engineering problem that directly involves the exploitation of oil wells subject to loss of circulation. To correct it, has been already proposed the use of granular materials, fibers, reducing the drilling fluid or cement paste density and even surface and downhole mixed systems. In this work, we proposed the development of a slurry mixed system, the first was a cement-based slurry and the second a geopolymer-based slurry. The cement-based slurry was formulated with low density and extenders, 12.0 ppg (1.438 g/cm ³), showing great thixotropic characteristics. It was added nano silica at concentrations of 0.5, 1.0 and 1.5 gps (66.88, 133.76 and 200.64 L/m3) and CaCl2 at concentrations of 0.5, 1, 0 and 1.5%. The second system is a geopolymer-based paste formulated from molar ratios of 3.5 (nSiO2/nAl2O3), 0.27 (nK2O/nSiO2), 1.07 (nK2O/nAl2O3) and 13.99 (nH2O/nK2O). Finally, we performed a mixture of these two systems, for their application for correction of circulation lost. To characterize the raw materials, XRD, XRF, FTIR analysis and titration were performed. The both systems were characterized in tests based on API RP10B. Compressive strength tests were conducted after curing for 24 hours, 7 and 28 days at 58 °C on the cement-based system and the geopolymer-based system. From the mixtures have been performed mixability tests and micro structural characterizations (XRD, SEM and TG). The results showed that the nano silica, when combined with CaCl2 modified the rheological properties of the cement slurry and from the concentration of 1.5 gpc (200.64 L / m³) it was possible to obtain stable systems. The system mixture caused a change in the microstructure of the material by favoring the rate of geopolymer formation to hinder the C3S phase hydration, thus, the production of CSH phases and Portlandite were harmed. Through the mixability tests it can be concluded that the system, due to reduced setting time of the mixture, can be applied to plug lost circulation zones when mixed downhole

Compósitos poliméricos a base de fibras de licuri: efeitos da hibridização e do envelhecimento ambiental acelerado

The gradual replacement of conventional materials by the ones called composite materials is becoming a concern about the response of these composites against adverse environmental conditions, such as ultraviolet radiation, high temperature and moist. Also the search for new composite using natural fibers or a blend of it with synthetic fibers as reinforcement has been studied. In this sense, this research begins with a thorough study of microstructural characterization of licuri fiber, as a proposal of alternative reinforcement to polymeric composites. Thus, a study about the development of two composite laminates was done. The first one, involving only the fiber of licuri and the second comprising a hybrid composite based of fiber glass E and the fiber of licuri, in order to know the performance of the fiber when of fiber across the hybridization process. The laminates were made in the form of plates using the tereftálica ortho-polyester resin as matrix. The composite laminate made only by licuri fiber had two reinforcing fabric layers of unidirectional licuri and the hybrid composite had two reinforcing layers of unidirectional licuri fabric and three layers of fiber short glass-E mat. Finally, both laminates was exposed to aging acceleration in order to study the influence of environmental degradation involving the mechanical properties and fracture characteristics thereof. Regarding the mechanical properties of composites, these were determined through uniaxial tensile tests, uniaxial compression and three bending points for both laminates in original state, and uniaxial tensile tests and three bending points after accelerated aging. As regards the study of structural degradation due to aging of the laminates, it was carried out based on microscopic analysis and microstructure, as well as measuring weight loss. The characteristics of the fracture was performed by macroscopic and microscopic (optical and SEM) analysis. In general, the laminated composites based on fiber licuri showed some advantages in their responses to environmental aging. These advantages are observed in the behavior related to stiffness as well as the microstructural degradation and photo-oxidation processes. However, the structural integrity of this laminate was more affected in case the action of uniaxial tensile loads, where it was noted a lower rate of withholding his last resistance property

Preparação e caracterização de catalisadores à base de titânio suportado em MCM-41 para produção de compostos oxigenados através da pirólise catalítica do capim elefante

In recent years, the area of advanced materials has been considerably, especially when it comes to materials for industrial use, such as is the case with structured porosity of catalysts suitable for catalytic processes. The use of catalysts combined with the fast pyrolysis process is an alternative to the oxygenate production of high added value, because, in addition to increasing the yield and quality of products, allows you to manipulate the selectivity to a product of interest, and therefore allows greater control over the characteristics of the final product. Based on these arguments, in this work were prepared titanium catalysts supported on MCM-41 for use in catalytic pyrolysis of biomass, called elephant grass. The reactions of pyrolysis of biomass were performed in a micro pyrolyzer, Py-5200, coupled to GC / MS, the company CDS Corporation, headquartered in the United States. The catalysts Ti-MCM-41 in different molar ratios were characterized by XRD, TG / DTG, FT-IR, SEM, XRF, UV-visible adsorption of nitrogen and the distribution of particle diameter and specific surface area measurement by the BET method. From the catalytic tests it was observed that the catalysts synthesized showed good results for the pyrolysis reaction.The main products were obtained a higher yield of aldehydes, ketones and furan. It was observed that the best reactivity is a direct function of the ratio Si/Ti, nature and concentration of the active species on mesoporous supports. Among the catalysts Ti-MCM-41 (molar ratio Si / Ti = 25 and 50), the ratio Si / Ti = 25 (400 ° C and 600 ° C) favored the cracking of oxygenates such as acids , aldehydes, ketones, furans and esters. Already the sample ratio Si / Ti = 50 had the highest yield of aromatic oxygenates

Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó

Carbide reinforced metallic alloys potentially improve some important mechanical properties required for the overall use of important engineering materials such as steel and nickel. Nevertheless, improved performance is achieved not only by composition enhancement but also by adequate processing techniques, such as novel sintering methods in the case of powder metallurgy. The method minimizes energy losses in addition to providing uniform heating during sintering. Thus, the general objective of this study was to evaluate the density, hardness, flexural strength, dilatometric behavior and to analyze the microstructure of metal matrix composites based nickel with addition of carbides of tantalum and / or niobium when sintered in a conventional furnace and Plasma assisted debinding and sintering (PADS). Initially, were defineds best parameters of granulation, screening and mixing procedure. After, mixtures of carbonyl Ni and 5%, 10% and 15 wt.% NbC and TaC were prepared in a Y-type mixer under wet conditions during 60 minutes. The mixtures were then dried and granulated using 1.5 wt. % paraffin diluted in hexane. Granulates were cold pressed under 600 MPa. Paraffin was then removed from the pressed pellets during a pre-sintering process carried out in a tubular furnace at 500 °C during 30 min. The heating rate was 3 ºC/min. The pellets were then sintered using either a plasma assisted reactor or a conventional resistive tubular furnace. For both methods, the heating rate was set to 8 ºC/min up to 1150 °C. The holding time was 60 minutes. The microstructure of the sintered samples was evaluated by SEM. Brinell hardness tests were also carried out. The results revealed that higher density and higher hardness values were observed in the plasma-assisted sintered samples. Hardness increased with the concentration of carbides in the Ni-matrix. The flexural strength also increased by adding the carbides. The decline was larger for the sample with addition of 5% 5% TaC and NbC. In general, compositions containing added carbide 10% showed less porous and more uniform distribution of carbides in the nickel matrix microstructural appearance. Thus, both added carbide and plasma sintering improved density, hardness, flexural strength and microstructural appearance of the composites

Modelagem molecular na caracterização eletrônica de oligopeptídeos e na descrição quântica da interação fármaco-receptor

In this dissertation, the theoretical principles governing the molecular modeling were applied for electronic characterization of oligopeptide α3 and its variants (5Q, 7Q)-α3, as well as in the quantum description of the interaction of the aminoglycoside hygromycin B and the 30S subunit of bacterial ribosome. In the first study, the linear and neutral dipeptides which make up the mentioned oligopeptides were modeled and then optimized for a structure of lower potential energy and appropriate dihedral angles. In this case, three subsequent geometric optimization processes, based on classical Newtonian theory, the semi-empirical and density functional theory (DFT), explore the energy landscape of each dipeptide during the search of ideal minimum energy structures. Finally, great conformers were described about its electrostatic potential, ionization energy (amino acids), and frontier molecular orbitals and hopping term. From the hopping terms described in this study, it was possible in subsequent studies to characterize the charge transport propertie of these peptides models. It envisioned a new biosensor technology capable of diagnosing amyloid diseases, related to an accumulation of misshapen proteins, based on the conductivity displayed by proteins of the patient. In a second step of this dissertation, a study carried out by quantum molecular modeling of the interaction energy of an antibiotic ribosomal aminoglicosídico on your receiver. It is known that the hygromycin B (hygB) is an aminoglycoside antibiotic that affects ribosomal translocation by direct interaction with the small subunit of the bacterial ribosome (30S), specifically with nucleotides in helix 44 of the 16S ribosomal RNA (16S rRNA). Due to strong electrostatic character of this connection, it was proposed an energetic investigation of the binding mechanism of this complex using different values of dielectric constants (ε = 0, 4, 10, 20 and 40), which have been widely used to study the electrostatic properties of biomolecules. For this, increasing radii centered on the hygB centroid were measured from the 30S-hygB crystal structure (1HNZ.pdb), and only the individual interaction energy of each enclosed nucleotide was determined for quantum calculations using molecular fractionation with conjugate caps (MFCC) strategy. It was noticed that the dielectric constants underestimated the energies of individual interactions, allowing the convergence state is achieved quickly. But only for ε = 40, the total binding energy of drug-receptor interaction is stabilized at r = 18A, which provided an appropriate binding pocket because it encompassed the main residues that interact more strongly with the hygB - C1403, C1404, G1405, A1493, G1494, U1495, U1498 and C1496. Thus, the dielectric constant ≈ 40 is ideal for the treatment of systems with many electrical charges. By comparing the individual binding energies of 16S rRNA nucleotides with the experimental tests that determine the minimum inhibitory concentration (MIC) of hygB, it is believed that those residues with high binding values generated bacterial resistance to the drug when mutated. With the same reasoning, since those with low interaction energy do not influence effectively the affinity of the hygB in its binding site, there is no loss of effectiveness if they were replaced.

A investigação criminal e a vedação ao anonimato no sistema jurídico brasileiro

The thesis, prepared with basis on deductive reasoning (through the utilization of general concepts of the fundamental rights theory) and on inductive logic (by means of the consideration of particular situations in which the theme has been approached) deals with the criminal investigation and the prohibition of anonymity in the Brazilian law system. The state criminal investigation activity presents not only a substantial constitutional basis, due to the objective dimension of fundamental rights (which imposes an obligation to protect these essential values), but also a formal constitutional basis, arising from the administrative principles of rule of law, morality and efficiency, referred to in article 37 of the Constitution. The criminal investigation, however, is not an unlimited pursuit, being restrained by the duty to consider fundamental rights that oppose to its realization. One of the limits of the state investigation activity, in the Brazilian law system, is the prohibition of anonymity, referred to in article 5°, IV, of the Constitution. This prohibition is a direct constitutional restriction to the freedom of expression that aims to ensure the credibility of the diffusion of ideas and prevent the abusive exercise of this fundamental right, which could harm both persons and the state, with no possibility of punishment to the offending party. Generally, based on this prohibition, it is affirmed that a criminal investigation cannot begin and progress founded on anonymous communication of crimes. Informations about crimes to the investigative authorities require the correct identification of the stakeholders. Therefore, it is sustained that the prohibition of anonymity also comprehends the prohibition of utilization of pseudonyms and heteronyms. The main purpose of this essay is to recognize the limits and possibilities in starting and conducting criminal investigations based on communication of crimes made by unidentified persons, behind the veil of anonymity or hidden by pseudonyms or heteronyms. Although the prohibition of article 5°, IV, of the Constitution is not submitted to direct or indirect constitutional restrictions, this impediment can be object of mitigation in certain cases, in attention to the constitutional values that support state investigation. The pertinence analysis of the restrictions to the constitutional anonymity prohibition must consider the proportionality, integrated by the partial elements of adequacy, necessity and strict sense proportionality. The criminal investigation is a means to achieve a purpose, the protection of fundamental rights, because the disclosure of facts, through the investigatory activity, gives rise to the accomplishment of measures in order to prevent or punish the violations eventually verified. So, the start and the development of the state criminal investigation activity, based on a crime communication carried out by an unidentified person, will depend on the demonstration that the setting up and continuity of an investigation procedure, in each case, are an adequate, necessary and (in a strict sense) proportional means to the protection of fundamental rights

Importância do gerenciamento com base em dados estudo de caso : farmácias de manipulação do Estado do Rio Grande do Norte

Last century Six Sigma Strategy has been the focus of study for many scientists, between the discoveries we have the importance of data process for the free of error product manufactory. So, this work focuses on data quality importance in an enterprise. For this, a descriptive-exploratory study of seventeen pharmacies of manipulations from Rio Grande do Norte was undertaken with the objective to be able to create a base structure model to classify enterprises according to their data bases. Therefore, statistical methods such as cluster and discriminant analyses were used applied to a questionnaire built for this specific study. Data collection identified four group showing strong and weak characteristics for each group and that are differentiated from each other

Segurança da informação no correio eletrônico com base na ISO/IEC 17799 :um estudo de caso em uma instituição superior com foco no treinamento

The electronic mail service is one of the most Internet services that grow in the corporate environment. This evolution is bringing several problems for the organizations, especially to information that circulates inside of the corporate net. The lack of correct orientation to the people, about the usage and the security importance of these resources, is leaving breaches and causing misusage and overuse of service, for example. In recent literature, it starts to coming out several ideas, which has helped to rganizations how to plain and how to implement the information security system to the electronic mail in computer environment. However, these ideas are still not placed in practice in many companies, public or private. This dissertation tries to demonstrate the results of a research that has like goal, identify the importance that user training has over the information security policy, through a case study inside of private superior education institute in this state. Besides, this work had by basic orientation the ISO/IEC 17799, which talk about People Security. This study was developed over a proposed model to this research, which looked for offer conditions to guide the institution studied, how to plan better a information security policy to the electronic mail. Also, this research has an exploratory and descreptive nature and your type, qualitative. Firstly, it was applied na questionary to the information technology manager, as better way to get some general data and to deepen the contact which still then, it was being kept through e-mail. Thereupon this first contact, eleven interviews were done with the same manager, beside one interview with twenty-four users, among employees e students. After that to collect and transcript the interviews, were review with the manager all informations given, to correct any mistakes and to update that informations, to then, start the data analyze. The research suggests that the institution has a pro attitude about the information security policy and the electronic mail usage. However, it was clear that answers have their perception about information security under a very inexperient way, derived of a planning lack in relation to training program capable to solve the problem

Envelhecimento ambiental em compósitos poliméricos à base de tecidos de reforços híbridos

The utilization of synthetic fibers for plastic reinforcement is more and more frequent and this growing interest requires that their mechanic behavior under the most variable conditions of structural applications be known. The use of such materials in the open and exposed to the elements is one of them. In this case, it becomes extremely necessary to study their mechanical properties (strength, stiffness) and the mechanism of fracture by which the environment aging them out. In order to do that, the material must be submitted to hot steam and ultraviolet radiation exposure cycles, according to periods of time determined by the norms. This study proposal deals with the investigation of accelerated environmental aging in two laminated polymeric composites reinforced by hybrid woven made up of synthetic fibers. The configurations of the laminated composites are defined as: one laminate reinforced with hybrid woven of glass fibers/E and Kevlar fibers/49 (LHVK) and the other laminate is reinforced with hybrid tissue of glass fibers/E and of carbon fibers AS4 (LHVC). The woven are plane and bidirectional. Both laminates are impregnated with a thermofix resin called Derakane 470-300 Epoxy Vinyl-Ester and they form a total of four layers. The laminates were industrially manufactured and were made through the process of hand-lay-up. Comparative analyses were carried out between their mechanical properties by submitting specimen to uniaxial loading tractions and three-point flexion. The specimen were tested both from their original state, that is, without being environmentally aging out, and after environmental aging. This last state was reached by using the environmental aging chamber

Estudo dos óxidos A2B2O7 e ABO3 a base de terras raras, para aplicações térmicas e catalíticas a altas temperaturas

Rare earth elements have recently been involved in a range of advanced technologies like microelectronics, membranes for catalytic conversion and applications in gas sensors. In the family of rare earth elements like cerium can play a key role in such industrial applications. However, the high cost of these materials and the control and efficiencies associated processes required for its use in advanced technologies, are a permanent obstacle to its industrial development. In present study was proposed the creation of phases based on rare earth elements that can be used because of its thermal behavior, ionic conduction and catalytic properties. This way were studied two types of structure (ABO3 and A2B2O7), the basis of rare earths, observing their transport properties of ionic and electronic, as well as their catalytic applications in the treatment of methane. For the process of obtaining the first structure, a new synthesis method based on the use of EDTA citrate mixture was used to develop a precursor, which undergone heat treatment at 950 ° C resulted in the development of submicron phase BaCeO3 powders. The catalytic activity of perovskite begins at 450 ° C to achieve complete conversion at 675 ° C, where at this temperature, the catalytic efficiency of the phase is maximum. The evolution of conductivity with temperature for the perovskite phase revealed a series of electrical changes strongly correlated with structural transitions known in the literature. Finally, we can establish a real correlation between the high catalytic activity observed around the temperature of 650 ° C and increasing the oxygen ionic conductivity. For the second structure, showed clearly that it is possible, through chemical processes optimized to separate the rare earth elements and synthesize a pyrochlore phase TR2Ce2O7 particular formula. This "extracted phase" can be obtained directly at low cost, based on complex systems made of natural minerals and tailings, such as monazite. Moreover, this method is applied to matters of "no cost", which is the case of waste, making a preparation method of phases useful for high technology applications

Análise da salubridade do meio urbano com base na utilização de índices ambientais: aplicação na bacia de drenagem XII da cidade do Natal-RN

The growing accumulation of people in urban centers caused chronic problems of the cities to begin to take an increasingly unsustainable. Primarily related to lack of infrastructure coupled with sanitation and lack of investment in critical sectors such as health, education, housing and transportation, these problems start to deteriorate markedly the quality of life of city dwellers and put into test management policies of the spaces urbanized. To reverse this situation, shows is essential to the use of tools (highlighting this harvest rates and environmental indicators) that help in assessing the current conditions and may assist in predicting future scenarios. From the information listed above, now put the research seeks to present an index called ISBA Environmental (Sanitation Index) which looks at the four urban systems (water, sewer, solid waste and urban drainage) from the viewpoint of application in a geographical cutout specific - in this case the Drainage Basin XII, defined by the Plan of Urban Drainage Stormwater in the city of Natal, capital of Rio Grande do Norte. This index, together with analysis of other factors sought to trace the current conditions of the basin and thus, assist in proposing the best solutions. For the preparation of the index was applied a questionnaire with a sample of 384 (three hundred eighty-four) households that aimed to study two variables: access to services and satisfaction of the population in relation to these. The ISBA has shown that the system is the most deficient collection and disposal of effluents (ICE = 47.66%), followed by the drainage of rainwater (IDAP = 54.17%), water supply (AAI = 61, 36) and solid waste collection (IRS = 78.28). With the ISBA was possible to verify that the qualitative data shows whose subjectivity is evident (as is the case of user satisfaction) can be of great importance when an assessment, since we obtained the correlation coefficient between the variables "Access" and " Satisfaction "equal to 0.8234, showing a strong correlation between the existence / quality of service offered and the impressions of the population that receives them

Carregadores de oxigênio a base de níquel suportado em materiais mesooros para aplicação na recirculação química com reforma (RQR)

Oxygen carriers are metal oxides which have the ability to oxidize and reduce easily by various cycles. Due to this property these materials are widely usedin Chemical-Looping Reforming processes to produce H2 and syngas. In this work supports based on MCM-41 and La-SiO2 were synthesized by hydrothermal method. After the synthesis step they were calcined at 550°C for 2 hours and characterized by TG, XRD, surface area using the BET method and FTIR spectroscopy. The deposition of active phase, in this case Nickel, took place in the proportions of 5, 10 and 20% by weight of metallic nickel, for use as oxygen carriers.The XRD showed that increasing in the content of Ni supported on MCM-41 resulted in a decrease in spatial structure and lattice parameter of the material. The adsorption and desorption curves of the MCM-41 samples exhibited variations with the increase of Ni deposited. Surface area, average pore diameter and wall density of silica showed significant changes , due to the increase of the active phase on the mesoporous material. By other hand, in the samples with La-SiO2 composition was not observed peaks characteristic of hexagonal structure, in the XRD diffractogram. The adsorption/desorption isotherms of nitrogen observed are type IV, characteristic of mesoporous materials. The catalytic test indicates that the supports have no influence in the process, but the nickel concentration is very important, because the results for minor concentration of nickel are not good. The ratio H2/O2 was close to 2, for all 15 cycles involving the test storage capacity of O2, indicating that the materials are effective for oxygen transport

Geração de processos WS-BPEL com base em um algoritmo de reescrita de regras

Web services are computational solutions designed according to the principles of Service Oriented Computing. Web services can be built upon pre-existing services available on the Internet by using composition languages. We propose a method to generate WS-BPEL processes from abstract specifications provided with high-level control-flow information. The proposed method allows the composition designer to concentrate on high-level specifi- cations, in order to increase productivity and generate specifications that are independent of specific web services. We consider service orchestrations, that is compositions where a central process coordinates all the operations of the application. The process of generating compositions is based on a rule rewriting algorithm, which has been extended to support basic control-flow information.We created a prototype of the extended refinement method and performed experiments over simple case studies

Avaliação da usabilidade e da arquitetura da informação do site do Instituto do Cérebro da UFRN: um estudo de caso com base nas opiniões dos usuários da instituição

The objective of the current piece of research presents was draw up a list of recommendations for the site of the Instituto do Cérebro da Universidade Federal do Rio Grande do Norte, with an emphasis on fault identification in usability and information architecture, through the application of design techniques with users of the institution. From the use of the following techniques: Cardsorting, applied to a group of six people as target public, such as professor, administrative technicians and graduate student of the institution; Interviews, carried out with the director of the Instituto do Cérebro, secretaries of the undergraduate and graduate courses; Cooperative Evaluation applied in two ways: in group and individually. The evaluation in group was fulfilled in four sessions that occurred with a group composed of six people who are part of the technical staff of the Instituto do Cérebro. In the Individual Cooperative Evaluation, eight users (graduate students and administrative technicians of the Instituto do Cérebro da UFRN) performed tasks which are frequently fulfilled by users from the public target in the site of the Instituto do Cérebro. After each session of the Individual Cooperative Evaluation, a questionnaire of the user´s satisfaction was used about his or her perception in regard to the site usability and utility of the mentioned institute site. Therefore, it was concluded that, by means of the analysis of the results and the triangulation of the obtained data in each one of the techniques applied with the users, in the present piece of research, problems were verified, among others; all related to the unsuitable use of the interface elements, navigation, labeling of some menu terms, and still, the lack of search space and integration with the social networks – besides the lack, positioning and inappropriate formatting of information that would be of high relevance to the users. Finally, a list of recommendations is presented and this can be used in a future interface redesign with the goal to improve the information architecture and the usability of the site of the Instituto do Cérebro da Universidade Federal do Rio Grande do Norte.

A probabilistic analysis of the biometrics menagerie existence: case study in fingerprint data

Until recently the use of biometrics was restricted to high-security environments and criminal identification applications, for economic and technological reasons. However, in recent years, biometric authentication has become part of daily lives of people. The large scale use of biometrics has shown that users within the system may have different degrees of accuracy. Some people may have trouble authenticating, while others may be particularly vulnerable to imitation. Recent studies have investigated and identified these types of users, giving them the names of animals: Sheep, Goats, Lambs, Wolves, Doves, Chameleons, Worms and Phantoms. The aim of this study is to evaluate the existence of these users types in a database of fingerprints and propose a new way of investigating them, based on the performance of verification between subjects samples. Once introduced some basic concepts in biometrics and fingerprint, we present the biometric menagerie and how to evaluate them.