Modelagem numérica de uma estrutura de contenção de estacas espaçadas atirantadas em areia

Retaining walls design involves factors such as plastification, loading and unloading, pre-stressing, excessive displacements and earth and water thrust. Furthermore, the interaction between the retained soil and the structure is rather complex and hard to predict. Despite the advances in numerical simulation techniques and monitoring of forces and displacements with field instrumentation, design projects are still based on classical methods, whose simplifying assumptions may overestimate structural elements of the retaining wall. This dissertation involves a three-dimensional numerical study on the behavior of a retaining wall using the finite element method (FEM). The retaining wall structure is a contiguous bored pile wall with tie-back anchors. The numerical results were compared to data obtained from field instrumentation. The influence of the position of one or two layers of anchors and the effects of the construction of a slab bounded at the top of the retaining wall was evaluated. Furthermore, this study aimed at investigating the phenomenon of arching in the soil behind the wall. Arching was evaluated by analyzing the effects of pile spacing on horizontal stresses and displacements. Parametric analysis with one layers of anchors showed that the smallest horizontal displacements of the structure were achieved for between 0.3 and 0.5 times the excavation depth. Parametric analyses with two anchor layers showed that the smallest horizontal displacements were achieve for anchors positioned in depths of 0.4H and 0.7H. The construction of a slab at the top of the retaining wall decreased the horizontal displacements by 0.14% times the excavation depth as compared to analyses without the slab. With regard to the arching , analyzes showed an optimal range of spacing between the faces of the piles between 0.4 and 0.6 times the diameter of the pile

Efeito da adição de argila expandida e adições minerais na formulação de concretos estruturais leves autoadensáveis

The search for alternative materials with lower density, reduction in heat transfer and propagation of noise associated with the ease of handling and application in concrete structures, represents an enormous challenge in the formulation and knowledge of the performance of self-compacting lightweight concrete, which has technology little known nationally, and appears on the international scene as an innovative material and alternative to conventional concrete. Based on these, this study set out to study self-compacting lightweight concrete made with two distinct grades of expanded clay associated with the addition of plasticizing/superplasticizers additives and mineral additions of metakaolin and bagasse ash of sugar cane. There is also an object of study, evaluation of pozzolanic activity of mineral admixtures and their influence on the durability characteristics of concrete. The rheological, physical, mechanical and microstructural analysis in this study served as basis in the classification of concretes autoadensáveis, targeting the national technical requirements for their classification in the category autoadensável and lightweight structural. The inclusion of mineral admixtures (metakaolin and bagasse ash of sugar cane), partial replacement of cement, pozzolanic activity and demonstrated maintenance of mechanical properties through the filler effect, a reduction of up to 76% of the nitrogen gas permeability in blend with 20% bagasse ash. All concretes had rheology (cohesion and consistency) suitable for self-adensability as well as strength and density inherent structural lightweight concrete without presenting phenomena of segregation and exudation

A influência da adição de caulim, quartzo e feldspato potássico na formulação de massas cerâmicas para telhas: Modelo estatístico

The production of roof tiles in the state of Rio Grande do Norte accounts for around 60% of the total of ceramic pieces produced. There is a need for investment to improve quality and productivity, thereby promoting technological innovations. Accordingly, the aim of this study is to determine the effect of kaolin, potassium feldspar and quartz in two standard formulations, as well as the effect of sintering temperature on the technological properties of linear firing shrinkage, water absorption and bending rupture stress, by fitting the statistical model and using multiple linear regression to assess the relationship between technological properties and independent variables. The raw materials were characterized using the following techniques: X-ray fluorescence (XRF), X-ray diffraction (XRF), rational analysis (RA), differential thermal analysis (DTA) and granulometric analysis (GA). The test specimens were compacted by uniaxial pressure (25 MPa), dried in a stove at 110 ºC for 24 hours and sinterized at 850 ºC, 950 ºC and 1050 ºC and held isothermal for 30 minutes. The results obtained indicate that the addition of kaolin to two standard formulations (M and R) promoted a reduction in water absorption values and an increase in bending rupture stress values. The sintering temperatures for group M that resulted in the lowest linear firing shrinkage and water absorption values were 850 ºC and 950 ºC, respectively, and the highest bending rupture stress values were reached at a temperature of 950 ºC. In the case of group R, the sintering temperature that obtained the lowest water absorption and linear firing shrinkage values was 850 ºC, and the highest bending rupture stress values were attained at a temperature of 1050 ºC. This work explains the statistical approach used to fit the model that describes the relationship between the technological properties and percentage of kaolin, quartz and feldspar, as well as the models that enable predictions, provided that the lower and upper limits of the percentage of clay minerals, flux and quartz used in this study are respected. Statistica 6 software was used and results were obtained by stepwise forward regression

Estudo da formulação de massas cerâmicas provenientes da região do Seridó-RN para fabricação de telhas

This work has for objective study compared the characteristics and technological properties of ceramic bodies from the region of Seridó-RN. The region under study has identified 23 cities where they were 80 ceramics industries. To define the universe of search, there was a survey of pottery that are part of APL Seridó next to the IEL. The characteristics and operating conditions of ceramics industries of the region were identified through a socio-economic questionnaire applied locally, which addressed issues such as: profiles of companies, production process etc. The analysis of information collected from 24 companies identified in seven cities shows that the vast majority of industries is small, with family structure, obsolete equipment and labo, little qualified. Most of the pottery works with low technical knowledge, poor control of the production process and product technology. The raw collected were submitted to analysis of X ray diffraction, chemical composition, termical analysis, particle size distribution and plasticity. Then were produced five formulations and made by uniaxial pressure at 25 MPa for firing in temperatures varying from 850 to 1050 °C. The firing technological properties evaluated were: mass loss to fire, lineal shrinkage, apparent density, apparent porosity, water absorption and flexural strength (3 points). The results indicated that the raw materials from the region have significant similarities in the composition chemical and mineralogical. Furthermore, it indicates the possibility of the use of cycles of firing faster and efficient than the current, limited to some clay mass burning of certain conditions

Formulação e caracterização de massas de grês porcelanato preparadas a partir de matérias-primas naturais do Rio Grande do norte e com adição de chamote de telhas

Traditional ceramics have an important role in the economy of Rio Grande do Norte. The local industries manufacture over 50 million shingles a month, corresponding to 60% of their overall production. As a result of processing flaws, roughly 20% of the production must be discarded, since little or no use has been envisaged for such fired components. Therefore, the use of this kind of residue, especially in the composition of other ceramic materials, comes as an interesting option from the economical and environmental point of view. In this scenario, the objective of the present study was to assess the effect of the addition of fired shingle waste in the composition of porcelainized stoneware tiles. To that end, two porcelainized stoneware tiles compositions were initially prepared. Subsequently, contents from 10 to 30% of roofing tiles chamote were added to each one of them. All raw materials and grog were characterized by FRX, XRD, and thermal analysis. The ceramics were fired using natural gas for 30 min at different temperatures, i.e. 1150, 1200 and 1250ºC, and fully characterized. The addition of roofing tiles chamote resulted in composition with superior properties compared to additive-free compositions. Porcelainized stoneware tiles products that fulfill required standards for practical applications were achieved

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)

Estudo da viabilidade técnica do uso das argilas da região do agreste potiguar para produção de peças cerâmicas: caracterização e formulação

In recent decades, ceramic products have become indispensable to the technological development of humanity, occupying important positions in scientific production and consequently in industrial production. One area of the economy that continues to absorb large amounts of the products of this sector is Construction. Among the branches of the ceramic industry, there are the red ceramic industry which is traditionally the basis of that economic sector. Among the reasons for which the red ceramic industry became popular in the country, and specifically in Rio Grande do Norte, is the abundance of this raw material, easily found throughout the national territory. However, it appears that the red ceramic industry has deficiencies in technology and skilled labor, resulting in the production of ceramic goods with low added value. Among the factors that determine the quality of the ceramic products red has the proper formulation of the ceramic mass, the conformation and the firing temperature. Thus, the overall goal of this work is to study the mineralogical and technological properties, two clays from the region of the Wasteland Potiguar industrial ceramist. Therefore, the raw materials were characterized by analysis of Xray diffraction (XRD) analysis, X-ray fluorescence (XRF), particle size analysis (FA), scanning electron microscopy (SEM), optical microscopy (OM ), plasticity index (PI), thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The technological properties of the material were analyzed by water absorption tests (AA%) porosity (% PA), the linear shrinkage (RT%), apparent density (MEA), loss on ignition (PF%) and flexural strength three points (TRF)

O impacto da utilização de design patterns nas métricas e estimativas de projetos de software: a utilização de padrões tem alguma influência nas estimativas?

VALENTIM, R. A. M. ; SOUZA NETO, Plácido Antônio de. O impacto da utilização de design patterns nas métricas e estimativas de projetos de software: a utilização de padrões tem alguma influência nas estimativas?. Revista da FARN, Natal, v. 4, p. 63-74, 2006

Projetos de letramento e formAÇÃO de professores de língua materna

O propósito do livro "Projetos de letramento e formAÇÃO de professores de língua materna" é contribuir para a compreensão dos projetos de letramento, entendendo-os como uma prática recontextualizada pelas atuais demandas sociais, ou seja, uma alternativa que promete priorizar a inclusão, a participação social e o reposicionamento identitário do professor e do aluno, e destacar a importância disso na formação docente e na ressignificação das práticas de leitura e de escrita no contexto escolar.

Percepções de maturidade em gerenciamento de projetos à luz da nova gestão pública: uma investigação com gestores das secretarias estaduais do Rio Grande do Norte

This study aimed to measure the perception of maturity project management of state boards of Rio Grande do Norte by the perception of its managers. Argues that project management has been highlighted as a critical factor for the success of any organization, because the projects are directly related to the set of activities that result in organizational innovation as products, services and processes and the improvement of project management is directly aligned with the main pillars of the New Public Management. Methodologically, this is a quantitative research of a descriptive nature in which 161 forms were applied with coordinators and subcoordinators of state departments of Rio Grande do Norte, culminating in a sampling error of less than 6% to 95% confidence according to the procedures finite sampling. The process of tabulation and analysis was done using the package Statistical Package for Social Sciences - SPSS 18.0 and worked with techniques such as mean, standard deviation, frequency distributions, cluster analysis and factor analysis. The results indicate that the levels of maturity in project management in state departments of Rio Grande do Norte is below the national average and that behavioral skills are the main problem for improving management in these departments. It was possible to detect the existence of two groups of different perceptions about the management of projects, indicating, according to the managers, there are islands of excellence in project management in some sectors of the state departments. It was also observed that there are eight factors that affect maturity in project management: Planning and Control , Development of Management Skills , Project Management Environment , Acceptance of the Subject Project Management , Stimulus to Performance , Project Evaluation and Learning , Project Management Office and Visibility of Project Managers . It concludes that the project management in state departments of Rio Grande do Norte has no satisfactory levels of maturity in project management, affecting the levels of efficiency and effectiveness of the state apparatus, which shows that some of the assumptions that guide the New Public Management are not getting the levels of excellence nailed by this management model

Maturidade de escritório de gerenciamento de projetos: o caso do Ministério Público do Rio Grande do Norte

The research aimed to evaluate the level of maturity of the project management office of the Public Ministry of the State of Rio Grande do Norte, on the model PMO Maturity Cube. It was based on a theoretical framework that includes project management, project management office and maturity of the project management office. The research was classified as to the purpose as exploratory and descriptive. According to the methods used was a case study, and how to approach is qualitative and quantitative. The research unit was the prosecutor of the State of Rio Grande do Norte, by two guys who represent all of the participants in the project management office of the institution. These subjects were chosen because they act with the office since the foundation of the same, having the knowledge necessary to deepen the research required, and experience with projects and work experience in the area. Data were collected through an adaptation of the evaluation form for the amplitude corporate developed and presented to the scientific environment for Pinto, Cota and Levin (2010). The results revealed that the level of maturity in the current strategic approach is 77%, and 97% desired; tactical approach in current is 66% and 97% desired, and the current operational approach is 78%, and 100% desired. He pointed out that several factors influence the level of maturity of the project management office of the Public Prosecutor and the recurrent related to information technology, regarding the storage and sharing of information. Concluded that the level of maturity of the project management office of the Public Ministry of the State of Rio Grande do Norte is advanced

Estrutura de organizações sociais: adaptação aos projetos sociais ou às pressões institucionais?

This is a study concerning in the structure of non governmental organizations, based on the institutional theory. It aims to understand the relation among structure, social projects and environmental influences, analyzing if there is coherence with project social or expresses adaptation to the institutional pressures of the environment. It introduces as theoretical support for the themes, studies about institutional theory and social structure. The research is descriptive and exploratory; it also applies to a study of case, based on the technical procedures. From the research universe, that was compound by non governmental organizations from Natal, RN, Brasil, it was chosen the Casa Renascer, a non governmental organization that works with the combat to the violence and sexual exploration of children and teenagers. The data collection process employed includes documental research, observations and semi structured research devices, guided by the organizational process proposed by Serva (1996) and by the institutional theory. The collected data were qualitatively treated. The analysis was divided into three parts, following the research matters. The social project characterization demonstrated that the organization went by three main phases. The first one, characterized by focus in women and girls education and health; the second shows the emphasis on girls in social risk situation, with preventive approach; and the last one, characterized by victims assistance of violence and sexual exploration. From the analysis using the institutional theory mechanisms, the results showed that exists coherence between structure and environmental influences, but a weak coherence between structure and social projects. It indicates as main determinant of the structure, an aspect forgotten by the institutional theory, the power. It was observed the presence from normative, coercive and mimetic mechanisms, highlighting normative influences

Avaliação de projetos sociais: análise da metodologia utilizada pela petrobrás

On the aggravation of social problems and the shortage of resources, the improvement of evaluation methods and control of its application, requiring more efficiency, efficacy, effectiveness and participation in its management, has been growing. As a result, emerges the importance of studying and developing such methodologies. The overall goal of this dissertation is to know what are the difficults to incorporate the point of view of executers and beneficiaries in evaluation process. To do so, has been done a research characterized as qualitative, with a field strategy using the case study of two social projects called Petrobras Child Program, situated in the metropolitan region of Natal, and Content Analysis technique for analyze the data. The conclusions of this work can assist in improving the process of projects evaluation financed by Petrobras, contributing with its social role, besides the possibility of encouraging a greater participation of other society actors, such as beneficiaries, in the evaluation process

Processo de formulação estratégica sob a perspectiva dos decisores da CAERN

Os estudos sobre estratégia têm se difundido há muitos anos e seu processo de formulação também está inserido no cotidiano dos gestores. O objetivo do presente trabalho é constatar se há relação entre o pensamento, formulação e mudança estratégica e o nível acadêmico, hierárquico e tempo no cargo dos decisores da CAERN. A abordagem teórica é realizada com os seguintes pontos: estratégia, Decisão e liderança organizacional e o processo de formação da estratégia (Pensamento estratégico; Formulação da estratégia; Mudança estratégica). O estudo é de caráter exploratório descritivo. Para a tabulação e análise dos dados, utilizou-se um programa estatístico em que foi adotada a técnica de análise fatorial, e verificou-se a confiabilidade da escala de Likert utilizada no questionário através do teste Alfa de Cronbach e análise de Spearman a fim de constatar a correlação das variáveis e proporcionar uma abordagem quantitativa à pesquisa. Todos os respondentes da pesquisa são tomadores de decisão cujos níveis hierárquicos que obtiveram representatividade na amostra foram coordenadores, gerentes e chefes de seção. A partir das análises dos resultados do estudo, constatou-se que, das hipóteses levantadas, apenas uma se mostrou coerente com a realidade dos profissionais responsáveis pela estratégia organizacional da empresa: Há correlação entre a formulação estratégica e o nível acadêmico dos decisores (no constructo de formulação deliberada). Notouse também que o nível de formação acadêmica (nível superior) é importante e influencia diretamente no processo da formulação estratégica. Conclui-se que na organização em estudo o conhecimento dos gestores interfere na formulação estratégica

Fatores críticos de sucesso para sistemas de informação de apoio ao gerenciamento de projetos: o caso SEBRAE/RN

Universidade Federal do Rio Grande do Norte