Simulação computacional da interação fluido-estrutura em bombas de cavidades progressivas

The pumping through progressing cavities system has been more and more employed in the petroleum industry. This occurs because of its capacity of elevation of highly viscous oils or fluids with great concentration of sand or other solid particles. A Progressing Cavity Pump (PCP) consists, basically, of a rotor - a metallic device similar to an eccentric screw, and a stator - a steel tube internally covered by a double helix, which may be rigid or deformable/elastomeric. In general, it is submitted to a combination of well pressure with the pressure generated by the pumping process itself. In elastomeric PCPs, this combined effort compresses the stator and generates, or enlarges, the clearance existing between the rotor and the stator, thus reducing the closing effect between their cavities. Such opening of the sealing region produces what is known as fluid slip or slippage, reducing the efficiency of the PCP pumping system. Therefore, this research aims to develop a transient three-dimensional computational model that, based on single-lobe PCP kinematics, is able to simulate the fluid-structure interaction that occurs in the interior of metallic and elastomeric PCPs. The main goal is to evaluate the dynamic characteristics of PCP s efficiency based on detailed and instantaneous information of velocity, pressure and deformation fields in their interior. To reach these goals (development and use of the model), it was also necessary the development of a methodology for generation of dynamic, mobile and deformable, computational meshes representing fluid and structural regions of a PCP. This additional intermediary step has been characterized as the biggest challenge for the elaboration and running of the computational model due to the complex kinematic and critical geometry of this type of pump (different helix angles between rotor and stator as well as large length scale aspect ratios). The processes of dynamic generation of meshes and of simultaneous evaluation of the deformations suffered by the elastomer are fulfilled through subroutines written in Fortan 90 language that dynamically interact with the CFX/ANSYS fluid dynamic software. Since a structural elastic linear model is employed to evaluate elastomer deformations, it is not necessary to use any CAE package for structural analysis. However, an initial proposal for dynamic simulation using hyperelastic models through ANSYS software is also presented in this research. Validation of the results produced with the present methodology (mesh generation, flow simulation in metallic PCPs and simulation of fluid-structure interaction in elastomeric PCPs) is obtained through comparison with experimental results reported by the literature. It is expected that the development and application of such a computational model may provide better details of the dynamics of the flow within metallic and elastomeric PCPs, so that better control systems may be implemented in the artificial elevation area by PCP

Modelagem computacional para avaliação da interação entre painéis de alvenaria e estrutura de suporte em concreto armado

The developed study proposes a new computer modeling efficient and easy to apply in usual project situations to evaluate the interaction between masonry panels and support structure. The proposed model simulates the behavior of the wall exclusively using frame finite elements, thus compounding an equivalent frame. The validation was performed in two ways: firstly, through the analysis of various panels of generic plans, comparing the results obtained from equivalent frame model with the ones from a reference model, which uses shell finite elements in discretization of the walls; and in a second step, comparing with the results of the experimental model of Rosenhaupt. The analyzes considered the linear elastic behavior for materials and consisted basically in the evaluation of vertical displacements and efforts in support beams, and tensions at the base of walls. Was also evaluated, from flat and threedimensional modeling of some walls from a real project, important aspects of the wall-beam interaction, e.g.: the presence of openings of doors and windows, arranged in any position; conditions of support and linking of beams; interference of moorings between walls; and consideration of wind action. The analysis of the achieved results demonstrated the efficiency of the proposed modeling, since they have very similar aspects in the distribution of stresses and efforts, always with intensities slightly larger than those of the reference and experimental models.

Influência da interação dipolar nas fases magnéticas de nanopartículas esféricas com estrutura núcleo@camada

Bi-magnetic core@shell nanoparticle has attracted attention several researchers because great applicability that they offer. The possibility of combining different functionalities of magnetic materials make them a key piece in many areas as in data processing permanent magnets and biomagnetics sistems. These nanoparticles are controlled by intrinsic properties of the core and shell materials as well as the interactions between them, besides size and geometry effects. Thus, it was developed in this thesis a theoretical study about dipolar interaction contribution between materials different magnetic properties in bi-magnetic core@shell nanoparticles conventional spherical geometry. The materials were analyzed CoFe2O4, MnFe2O4 e CoFe2 in various combinations and sizes. The results show that the impact of the core dipole field in the shell cause reverse magnetization early its, before of the core, in nanoparticle of CoFe2O4(22nm)@CoFe2(2nm), thereby causing a decrease coercivity field of 65% in comparection with simple nanoparticle of CoFe2O4 (HC=13.6 KOe) of same diameter. The large core anisotropy in conventional nanoparticle makes it the a stable dipolar field source in the shell, that varies length scale of the order of the core radius. Furthermore, the impact of dipolar field is greatly enhanced by the geometrical constraints and by magnetics properties of both core@shell materials. In systems with core coated with a thin shell of thickness less than the exchange length, the interaction interface can hold reversal the shell occurring an uniform magnetization reversal, however this effect only is relevant on systems where the dipole field effects is weak compared with the exchange interaction.

Influência da interação dipolar nas fases magnéticas de nanopartículas esféricas com estrutura núcleo@camada

Bi-magnetic core@shell nanoparticle has attracted attention several researchers because great applicability that they offer. The possibility of combining different functionalities of magnetic materials make them a key piece in many areas as in data processing permanent magnets and biomagnetics sistems. These nanoparticles are controlled by intrinsic properties of the core and shell materials as well as the interactions between them, besides size and geometry effects. Thus, it was developed in this thesis a theoretical study about dipolar interaction contribution between materials different magnetic properties in bi-magnetic core@shell nanoparticles conventional spherical geometry. The materials were analyzed CoFe2O4, MnFe2O4 e CoFe2 in various combinations and sizes. The results show that the impact of the core dipole field in the shell cause reverse magnetization early its, before of the core, in nanoparticle of CoFe2O4(22nm)@CoFe2(2nm), thereby causing a decrease coercivity field of 65% in comparection with simple nanoparticle of CoFe2O4 (HC=13.6 KOe) of same diameter. The large core anisotropy in conventional nanoparticle makes it the a stable dipolar field source in the shell, that varies length scale of the order of the core radius. Furthermore, the impact of dipolar field is greatly enhanced by the geometrical constraints and by magnetics properties of both core@shell materials. In systems with core coated with a thin shell of thickness less than the exchange length, the interaction interface can hold reversal the shell occurring an uniform magnetization reversal, however this effect only is relevant on systems where the dipole field effects is weak compared with the exchange interaction.

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.

Estudo in silico da interação da albumina de soro humano com o ibuprofeno

Currently, computational methods have been increasingly used to aid in the characterization of molecular biological systems, especially when they relevant to human health. Ibuprofen is a nonsteroidal antiinflammatory or broadband use in the clinic. Once in the bloodstream, most of ibuprofen is linked to human serum albumin, the major protein of blood plasma, decreasing its bioavailability and requiring larger doses to produce its antiinflamatory action. This study aimes to characterize, through the interaction energy, how is the binding of ibuprofen to albumin and to establish what are the main amino acids and molecular interactions involved in the process. For this purpouse, it was conducted an in silico study, by using quantum mechanical calculations based on Density Functional Theory (DFT), with Generalized Gradient approximation (GGA) to describe the effects of exchange and correlation. The interaction energy of each amino acid belonging to the binding site to the ligand was calculated the using the method of molecular fragmentation with conjugated caps (MFCC). Besides energy, we calculated the distances, types of molecular interactions and atomic groups involved. The theoretical models used were satisfactory and show a more accurate description when the dielectric constant ε = 40 was used. The findings corroborate the literature in which the Sudlow site I (I-FA3) is the primary binding site and the site I-FA6 as secondary site. However, it differs in identifying the most important amino acids, which by interaction energy, in order of decreasing energy, are: Arg410, Lys414, Ser 489, Leu453 and Tyr411 to the I-Site FA3 and Leu481, Ser480, Lys351, Val482 and Arg209 to the site I-FA6. The quantification of interaction energy and description of the most important amino acids opens new avenues for studies aiming at manipulating the structure of ibuprofen, in order to decrease its interaction with albumin, and consequently increase its distribution

Pré-fabricados lingüísticos: estrutura e funcionamento de sintagmas verbais idiomatizados - por uma abordagem cognitivo-funcional em sala de aula

This work aims at under the cognitive-functional perspective describing, inside the vast domain of the linguistic prefabs, the structure and the functioning of the Idiomatic Verb Phrases (SVIs), produced by speakers of the Portuguese from Brazil, located in Natal (RN). From the functionalist presupposition that the language is used essentially to assist to communicative demands, it is observed that its morphologic-syntactic structure is conditioned to the inherent pragmatic vicissitudes to the verbal interaction of subjects, socially heterogeneous and historically established. It is focalized, in the composition of SVIs, the relationships VT + OD (transitive verb + direct object), characterizing the syntactic-semantic nature of the verb and of the respective verbal complement. Those verb combinations + complement can be interpreted as lexical structures, reflexes of the idiomaticity inherent to conventional constructions already systematized in the users' of the language cultural repertoire. It is sought, still, to glimpse the cognitive and discursive motivations pertinent to that linguistic phenomenon. In the investigative process, are analyzed exclusive data of speech collected in Corpus Discurso & Gramática a lingua falada e escrita na cidade do Natal, organized by Furtado da Cunha (1998). The adopted methodological procedures configure as methods of empiric analysis and use of the intuition, being emphasized the qualitative approach (explanatory) of the data with quantitative support of statistical indicators. It shows, finally, a grating of didactic suggestions on SVIs, for Portuguese's classes, as subsidies to the educational practice in the Medium Teaching and in the course of Letters.

Efeitos da interação dipolar na nucleação de vórtices em nano-cilindros magnéticos

The effect of confinement on the magnetic structure of vortices of dipolar coupled ferromagnetic nanoelements is an issue of current interest, not only for academic reasons, but also for the potential impact in a number of promising applications. Most applications, such as nano-oscillators for wireless data transmission, benefit from the possibility of tailoring the vortex core magnetic pattern. We report a theoretical study of vortex nucleation in pairs of coaxial iron and Permalloy cylinders, with diameters ranging from 21nm to 150nm, and 12nm and 21nm thicknesses, separated by a non-magnetic layer. 12nm thick iron and Permalloy isolated (single) cylinders do not hold a vortex, and 21nm isolated cylinders hold a vortex. Our results indicate that one may tailor the magnetic structure of the vortices, and the relative chirality, by selecting the thickness of the non-magnetic spacer and the values of the cylinders diameters and thicknesses. Also, the dipolar interaction may induce vortex formation in pairs of 12nm thick nanocylinders and inhibit the formation of vortices in pairs of 21nm thick nanocylinders. These new phases are formed according to the value of the distance between the cylinderes. Furthermore, we show that the preparation route may control relative chirality and polarity of the vortex pair. For instance: by saturating a pair of Fe 81nm diameter, 21nm thickness cylinders, along the crystalline anisotropy direction, a pair of 36nm core diameter vortices, with same chirality and polarity is prepared. By saturating along the perpendicular direction, one prepares a 30nm diameter core vortex pair, with opposite chirality and opposite polarity. We also present a theoretical discussion of the impact of vortices on the thermal hysteresis of a pair of interface biased elliptical iron nanoelements, separated by an ultrathin nonmagnetic insulating layer. We have found that iron nanoelements exchange coupled to a noncompensated NiO substrate, display thermal hysteresis at room temperature, well below the iron Curie temperature. The thermal hysteresis consists in different sequences of magnetic states in the heating and cooling branches of a thermal loop, and originates in the thermal reduction of the interface field, and on the rearrangements of the magnetic structure at high temperatures, 5 produce by the strong dipolar coupling. The width of the thermal hysteresis varies from 500 K to 100 K for lateral dimensions of 125 nm x 65 nm and 145 nm x 65 nm. We focus on the thermal effects on two particular states: the antiparallel state, which has, at low temperatures, the interface biased nanoelement with the magnetization aligned with the interface field and the second nanoelement aligned opposite to the interface field; and in the parallel state, which has both nanoelements with the magnetization aligned with the interface field at low temperatures. We show that the dipolar interaction leads to enhanced thermal stability of the antiparallel state, and reduces the thermal stability of the parallel state. These states are the key phases in the application of pairs of ferromagnetic nanoelements, separated by a thin insulating layer, for tunneling magnetic memory cells. We have found that for a pair of 125nm x 65nm nanoelements, separated by 1.1nm, and low temperature interface field strength of 5.88kOe, the low temperature state (T = 100K) consists of a pair of nearly parallel buckle-states. This low temperature phase is kept with minor changes up to T= 249 K when the magnetization is reduced to 50% of the low temperature value due to nucleation of a vortex centered around the middle of the free surface nanoelement. By further increasing the temperature, there is another small change in the magnetization due to vortex motion. Apart from minor changes in the vortex position, the high temperature vortex state remains stable, in the cooling branch, down to low temperatures. We note that wide loop thermal hysteresis may pose limits on the design of tunneling magnetic memory cells

Interações entre a carboximetilcelulose, carbonato de cálcio e bentonita: repercussões sobre as propriedades dos fluidos de perfuração aquosos

The role of carboxymethylcellulose (CMC) in association to calcium carbonate particles (CaCO3) in most water-based drilling fluids is to reduce the fluid loss to the surrounding formation. Another essential function is to provide rheological properties capable of maintaining in suspension the cuttings during drilling operation. Therefore, it is absolutely essential to correlate the polymer chemical structure (degree of substitution, molecular weight and distribution of substituent) with the physical-chemical properties of CaCO3, in order to obtain the better result at lower cost. Another important aspect refers to the clay hydration inhibitive properties of carboxymethylcellulose (CMC) in drilling fluids systems. The clay swelling promotes an undesirable damage that reduces the formation permeability and causes serious problems during the drilling operation. In this context, this thesis consists of two main parts. The first part refers to understanding of interactions CMC-CaCO3, as well as the corresponding effects on the fluid properties. The second part is related to understanding of mechanisms by which CMC adsorption occurs onto the clay surface, where, certainly, polymer chemical structure, ionic strength, molecular weight and its solvency in the medium are responsible to affect intrinsically the clay layers stabilization. Three samples of carboximetilcellulose with different molecular weight and degree of substitution (CMC A (9 x 104 gmol DS 0.7), CMC B (2.5 x 105 gmol DS 0.7) e CMC C (2.5 x 105 gmol DS 1.2)) and three samples of calcite with different average particle diameter and particle size distribution were used. The increase of CMC degree of substitution contributed to increase of polymer charge density and therefore, reduced its stability in brine, promoting the aggregation with the increase of filtrate volume. On the other hand, the increase of molecular weight promoted an increase of rheological properties with reduction of filtrate volume. Both effects are directly associated to hydrodynamic volume of polymer molecule in the medium. The granulometry of CaCO3 particles influenced not only the rheological properties, due to adsorption of polymers, but also the filtration properties. It was observed that the lower filtrate volume was obtained by using a CaCO3 sample of a low average size particle with wide dispersion in size. With regards to inhibition of clay swelling, the CMC performance was compared to other products often used (sodium chloride (NaCl), potassium chloride (KCl) and quaternary amine-based commercial inhibitor). The low molecular weight CMC (9 x 104 g/mol) showed slightly lower swelling degree compared to the high molecular weight (2.5 x 105 g/mol) along to 180 minutes. In parallel, it can be visualized by Scanning Electron Microscopy (SEM) that the high molecular weight CMC (2.5 x 105 g/mol e DS 0.7) promoted a reduction in pores formation and size of clay compared to low molecular weight CMC (9.0 x 104 g/mol e DS 0.7), after 1000 minutes in aqueous medium. This behavior was attributed to dynamic of interactions between clay and the hydrodynamic volume of CMC along the time, which is result of strong contribution of electrostatic interactions and hydrogen bounds between carboxylate groups and hydroxyls located along the polymer backbone and ionic and polar groups of clay surface. CMC adsorbs on clay surface promoting the skin formation , which is responsible to minimize the migration of water to porous medium. With the increase of degree of substitution, it was observed an increase of pores onto clay, suggesting that the higher charge density on polymer is responsible to decrease its flexibility and adsorption onto clay surface. The joint evaluation of these results indicate that high molecular weight is responsible to better results on control of rheological, filtration and clay swelling properties, however, the contrary effect is observed with the increase of degree of substitution. On its turn, the calcite presents better results of rheological and filtration properties with the decrease of average viii particle diameter and increase of particle size distribution. According to all properties evaluated, it has been obvious the interaction of CMC with the minerals (CaCO3 and clay) in the aqueous medium

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

Lixo hospitalar: na estrutura curricular de cursos superiores de saude na cidade de Imperatriz – MA

SILVA, Dany Geraldo Kramer Cavalcanti e et al. Lixo hospitalar: na estrutura curricular de cursos superiores de saude na cidade de Imperatriz-MA. Educação Ambiental em Ação, v. 27, p. 00-10, 2009.

A estrutura burocrática de poder no stricto sensu em administração no Brasil: o caso do mestrado profissional em administração pública em Rede Nacional - PROFIAP

This study approaches bureaucratic organizational structures with the aim to understand the adherence procedure to virtual technologies in the stricto sensu educational administrative process. Thus, the author navigates through the formation of these organizations in Brazil with the intent to demonstrate the bureaucratic organizational culture and the consequent form of domination of those who detain power. In this epistemological construction, the author explores the culture s bureaucratic environment and the organizational power. In the analyses, it was observed the technological phenomenon in the ODL s administrative environment, which can explain the adherence procedure to structures and technological instruments for stricto sensu courses that, hypothetically, dilutes the traditional inherited organizational axiom. Therefore, it was utilized as object of study the Professional Master s degree in National Scale Public Administration PROFIAP, hence analyzing the documental content and the legislation related to institutionalization as well as the positioning of professors/coordinators and of the director of CAPES/MEC. Considering this axioms, it was concluded that the bureaucratic structures can admit ODL in the stricto sensu s environment. However, this can only be done as long as the adherence does not imply in a dilution of the traditional forms of power and institutional bureaucratic inherited dominance, as well as the alleged hegemony of the governmental structure in the educational administration adopted in person by the stricto sensu courses in Brazil

Determinantes da Estrutura de Capital de Companhias Abertas Brasileiras Não-Financeiras: Um Estudo Empírico com Dados em Painel

When a company desires to invest in a project, it must obtain resources needed to make the investment. The alternatives are using firm s internal resources or obtain external resources through contracts of debt and issuance of shares. Decisions involving the composition of internal resources, debt and shares in the total resources used to finance the activities of a company related to the choice of its capital structure. Although there are studies in the area of finance on the debt determinants of firms, the issue of capital structure is still controversial. This work sought to identify the predominant factors that determine the capital structure of Brazilian share capital, non-financial firms. This work was used a quantitative approach, with application of the statistical technique of multiple linear regression on data in panel. Estimates were made by the method of ordinary least squares with model of fixed effects. About 116 companies were selected to participate in this research. The period considered is from 2003 to 2007. The variables and hypotheses tested in this study were built based on theories of capital structure and in empirical researches. Results indicate that the variables, such as risk, size, and composition of assets and firms growth influence their indebtedness. The profitability variable was not relevant to the composition of indebtedness of the companies analyzed. However, analyzing only the long-term debt, comes to the conclusion that the relevant variables are the size of firms and, especially, the composition of its assets (tangibility).This sense, the smaller the size of the undertaking or the greater the representation of fixed assets in total assets, the greater its propensity to long-term debt. Furthermore, this research could not identify a predominant theory to explain the capital structure of Brazilian

Trabalho e família: um estudo da interação de papéis com secretários executivos

The balance between the demands of two important spheres of human life, work and family, has become a challenge due to the pressures of the contemporary that is expanding around the difficulties of reconciling these two comínios. In this sense, this research aimed to understand the work-family interaction in the perception of executive secretaries. The analysis approach used was qualitative research, by worrying about a reality that can not be quantified due to the subjectivity of his goal. The data collection technique used was the semistructured interview to twenty executive secretaries, servants of a Federal Institution of Higher Education. For the understanding and interpretation of the data, we used the technique of content analysis. The results of both analyzes identified the existence of conflict as enrichment in this interaction. The time was identified as the largest generator of conflict work. The overload, relationship stress and conflict emerged as elements common to both domains. As main implications of labor disputes, were revealed: problamas health for secretaries and stress. As main implications of family conflicts emerged: motivation for work, lower performance and lack of concentration. The attempt at balance was identified as the strategy most used by secretaries to minimize work-family conflict. The work-family enrichment was seen as resources that contribute to improving the lives of the secretary in both domains. The opportunity to add knowledge was highlighted as enriching element of work and family values ​​as elements enriching family. The support and experience emerged as enrichment items common to both domains. Regarding the implications of enrichment resulting from the interaction of work and family, the more perceived by respondents were: increased knowledge and skills, material and psychological benefits, improved quality of life and personal and professional fulfillment. From the perception of executive secretaries, work and family spheres of human life are essential and complementary, and that help is contrary, however, this relationship is the primary management of conflicts, ie, how the individual sees and manages the negative side of the work-family

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