Estudo das forças capilar, viscosa e gravitacional através de grupos adimensionais na simulação da drenagem gravitacional assistida por gás (GAGD)

The distribution and mobilization of fluid in a porous medium depend on the capillary, gravity, and viscous forces. In oil field, the processes of enhanced oil recovery involve change and importance of these forces to increase the oil recovery factor. In the case of gas assisted gravity drainage (GAGD) process is important to understand the physical mechanisms to mobilize oil through the interaction of these forces. For this reason, several authors have developed physical models in laboratory and core floods of GAGD to study the performance of these forces through dimensionless groups. These models showed conclusive results. However, numerical simulation models have not been used for this type of study. Therefore, the objective of this work is to study the performance of capillary, viscous and gravity forces on GAGD process and its influence on the oil recovery factor through a 2D numerical simulation model. To analyze the interplay of these forces, dimensionless groups reported in the literature have been used such as Capillary Number (Nc), Bond number (Nb) and Gravity Number (Ng). This was done to determine the effectiveness of each force related to the other one. A comparison of the results obtained from the numerical simulation was also carried out with the results reported in the literature. The results showed that before breakthrough time, the lower is the injection flow rate, oil recovery is increased by capillary force, and after breakthrough time, the higher is the injection flow rate, oil recovery is increased by gravity force. A good relationship was found between the results obtained in this research with those published in the literature. The simulation results indicated that before the gas breakthrough, higher oil recoveries were obtained at lower Nc and Nb and, after the gas breakthrough, higher oil recoveries were obtained at lower Ng. The numerical models are consistent with the reported results in the literature

A relevância dos eventos culturais para a economia criativa - pesquisa qualitativa na Praia da Pipa, Tibau do Sul/RN

Creative industry has promoted and strengthened the growth of various economic sectors in Brazil and abroad, thus stimulating the local economy in places with attractive and innovative sceneries for the consumer market. This essay focuses on studying the relevance of cultural events for the creative economy, and these may contribute to the social, cultural and economic development in Pipa, located in Rio Grande do Norte (Brazil). Cultural events promote a themed and creative environment which has worked as attraction mechanism for the increase of cultural, gastronomic and social leisure consumptions. Cultural and thematic events has been held in Pipa, such as Festival Literário da Pipa, Fest Bossa & Jazz da Pipa, Festival Literário Alternativo da Pipa and Festival Gastronômico da Pipa, which can attract the local, state, national and international audience. The research is characterized as a qualitative research about the problem approach. The field research is characterized by the ethnographic approach, using the techniques of participant observation, semi-structured interviews and photographic record. With the research results, we can point that Pipa promotes cultural events that move the economic dynamics, social and cultural, inserting new cultural habits in this urban space, and in some cases, rescuing the history of the place. In each event, the economic and political forces connect themselves to promote the infrastructure of these events, supporting the provision of services and products from the creative and cultural sectors. The theming of the studied events plunges the audience into stories that may have (or not) a connection to the local history. Therefore, it is perceived that this work brings the light to a place that presents itself as the protagonist of the state of Rio Grande do Norte in terms of renewal and economic, social and cultural change in its infrastructure and its potential for tourist attraction from the creative and cultural sectors.

Numerical simulation for dynamic positioning in pack ice

This thesis investigates the numerical modelling of Dynamic Position (DP) in pack ice. A two-dimensional numerical model for ship-ice interaction was developed using the Discrete Element Method (DEM). A viscous-elastic ice rheology was adopted to model the dynamic behaviour of the ice floes. Both the ship-ice and the ice-ice contacts were considered in the interaction force. The environment forces and the hydrodynamic forces were calculated by empirical formulas. After the current position and external forces were calculated, a Proportional-Integral-Derivative (PID) control and thrust allocation algorithms were applied on the vessel to control its motion and heading. The numerical model was coded in Fortran 90 and validated by comparing computation results to published data. Validation work was first carried out for the ship-ice interaction calculation, and former researchers’ simulation and model test results were used for the comparison. With confidence in the interaction model, case studies were conducted to predict the DP capability of a sample Arctic DP vessel.

A mathematical model for the maneuvering simulation of a propelled SPAR vessel

To predict the maneuvering performance of a propelled SPAR vessel, a mathematical model was established as a path simulator. A system-based mathematical model was chosen as it offers advantages in cost and time over full Computational Fluid Dynamics (CFD) simulations. The model is intended to provide a means of optimizing the maneuvering performance of this new vessel type. In this study the hydrodynamic forces and control forces are investigated as individual components, combined in a vectorial setting, and transferred to a body-fixed basis. SPAR vessels are known to be very sensitive to large amplitude motions during maneuvers due to the relatively small hydrostatic restoring forces. Previous model tests of SPAR vessels have shown significant roll and pitch amplitudes, especially during course change maneuvers. Thus, a full 6 DOF equation of motion was employed in the current numerical model. The mathematical model employed in this study was a combination of the model introduced by the Maneuvering Modeling Group (MMG) and the Abkowitz (1964) model. The new model represents the forces applied to the ship hull, the propeller forces and the rudder forces independently, as proposed by the MMG, but uses a 6DOF equation of motion introduced by Abkowitz to describe the motion of a maneuvering ship. The mathematical model was used to simulate the trajectory and motions of the propelled SPAR vessel in 10˚/10˚, 20˚/20˚ and 30˚/30˚ standard zig-zag maneuvers, as well as turning circle tests at rudder angles of 20˚ and 30˚. The simulation results were used to determine the maneuverability parameters (e.g. advance, transfer and tactical diameter) of the vessel. The final model provides the means of predicting and assessing the performance of the vessel type and can be easily adapted to specific vessel configurations based on the generic SPAR-type vessel used in this study.

Development of an instrumented customizable total knee prosthesis for experimental tests.

Total knee arthroplasty (TKA) has revolutionized the life of millions of patients and it is the most efficient treatment in cases of osteoarthritis. The increase in life expectancy has lowered the average age of the patient, which requires a more enduring and performing prosthesis. To improve the design of implants and satisfying the patient's needs, a deep understanding of the knee Biomechanics is needed. To overcome the uncertainties of numerical models, recently instrumented knee prostheses are spreading. The aim of the thesis was to design and manifacture a new prototype of instrumented implant, able to measure kinetics and kinematics (in terms of medial and lateral forces and patellofemoral forces) of different interchangeable designs of prosthesis during experiments tests within a research laboratory, on robotic knee simulator. Unlike previous prototypes it was not aimed for industrial applications, but purely focusing on research. After a careful study of the literature, and a preliminary analytic study, the device was created modifying the structure of a commercial prosthesis and transforming it in a load cell. For monitoring the kinematics of the femoral component a three-layers, piezoelettric position sensor was manifactured using a Velostat foil. This sensor has responded well to pilot test. Once completed, such device can be used to validate existing numerical models of the knee and of TKA and create new ones, more accurate.It can lead to refinement of surgical techniques, to enhancement of prosthetic designs and, once validated, and if properly modified, it can be used also intraoperatively.

A influência do amortecimento viscoelástico na estabilidade aeroelástica de painéis aeronáuticos

Since the creation of supersonic vehicles, during the Second World War, the engineers have given special attention to the interaction between the aerodynamic efforts and the structures of the aircrafts due to a highly destructive phenomenon called flutter in aeronautical panel. Flutter in aeronautical panels is a self-excited aeroelastic phenomenon, which can occurs during supersonic flights due to dynamic instability of inertia, elastic and aerodynamic forces of the system. In the flutter condition, when the critical aerodynamic pressure is reached, the vibration amplitudes of the panel become dynamically unstable and increase exponentially with time, affecting significantly the fatigue life of the existing aeronautical components. Thus, in this paper, the interest is to investigate the possibility of reducing the effects of the supersonic aeroelastic instability of rectangular plates by applying passive constrained viscoelastic layers. The rationale for such study is the fact that as the addition of viscoelastic materials provides decreased vibration amplitudes it becomes important to quantify the suppression of plate flutter coalescence modes that can be obtained. Moreover, despite the fact that much research on the suppression of panel flutter has been carried out by using passive, semi-active and active control techniques, very few of them are adapted to deal with the problem of estimating the flutter speeds of viscoelastic systems, since they must conveniently account for the frequency- and temperature-dependent behavior of the viscoelastic material. In this context, two different model of viscoelastic material are developed and applied to the model of sandwich plate by using finite elements. After the presentation of the theoretical foundations of the methodology, the description of a numerical study on the flutter analysis of a three-layer sandwich plate is addressed.

Weathering the crisis? Managing democracy at a national broadcaster

With post-2008 political and economic crises as its backdrop, this inquiry into the political roles and functions of public service broadcasting (PSB) in Ireland is principally concerned with examining the capacities for and actuality of critical and counter-hegemonic professional journalistic and institutional mediations of crisis. Recognising the diversity of influences on the normative identity of Irish PSB, the dissertation adopts a sociological approach that acknowledges the systemic embedding of media institutions in the broader field of power. An initial tracing of the formative impacts of endogenous and exogenous forces on the democratic horizons of PSB suggests that the present crisis conjuncture does not represent promising terrain for engendering critical crisis and recovery imaginaries. A methodologically diverse intra-institutional empirical research agenda aims to explore at close hand Irish PSB’s contingent navigation of crisis, encompassing ethnographic observation in the newsroom, practitioner interviews and textual analysis of broadcast output. These methods afford close analysis of practices of journalistic production and reflexivity, self-conceptions of the journalistic habitus, and ideological affinities of crisis framings in broadcast output. These analyses are supplemented by a participant observation study of the possibilities for public agenda-building in a key institutional venue of public participation in broadcasting governance. The findings offer an evidential basis for the arguments that the crisis has prompted only minimal changes to professional norms and practices of representation and inclusion; that journalistic crisis framings tend toward effecting hegemonic repair by lending support to neoliberal crisis and recovery imaginaries; and that the institutional openings for the building of public counterpower are highly constrained. The overall conclusion is made that the normative democratic orientation embedded in the professional and institutional projects of public service broadcasting help render it ill-equipped to act as a re-democratising countervailing power against the democratic regressions engendered by the present crisis of democratic capitalism.

Global Factors Affecting Women's Participation in Leadership

This dissertation is a multi-level, cross-cultural study of women in leadership conducted with both macro-society data and individual-level data aggregated to the country level. The research questions are, “What macro and micro forces are hindering or advancing women into business or political leadership?” “How do these forces impact the level of women’s involvement in business and political leadership in a particular country?” Data was collected from 10 secondary sources, available for 213 countries, and includes about 300 variables for business leadership (N=115) and political leadership (N=181). To date, most women in leadership research has been Western- or US- based, and little rigorous empirical, multi-level research has been done across countries. The importance of cross-cultural studies on women in leadership stems from the potential to better understand why some countries have more women in positions of both business and political leadership; and the factors that affect women’s involvement in such positions in different countries. A “Levels of Women’s Participation in Leadership” country model is tested using cluster and discriminant analyses. Results indicate that the factors that affect women’s participation in leadership in countries with fewer women leaders are different from the factors that affect women’s participation in countries with high levels of participation. This dissertation proposes that initiatives to increase participation of women in leadership need to consider the relevant factors that significantly affect countries at certain Levels of Women’s Participation in Leadership.

Casamientos católicos secretos de funcionarios y militares en Buenos Aires e Hispanoamérica : Intrínseca constitución de algunos de sus matrimonios secretos, de conciencia u ocultos. Siglos XVIII-XIX

El objetivo del trabajo es dar a conocer los casamientos secretos efectuados por la Iglesia Católica a espaldas del Rey y las autoridades virreinales en Buenos Aires; especialmente, de funcionarios y oficiales de las fuerzas terrestres y navales de la monarquía en el siglo XVIII. Los análisis se basan en el Derecho Canónico y lo establecido en el Concilio de Trento (1545-1563). Una variada bibliografía relacionada con la constitución de las familias en Europa e Hispanoamérica permitió explorar un marco desconocido de lo ocurrido con estos matrimonios secretos también llamados de conciencia u ocultos. Se explicitan las características de este tipo de nupcias y la casuística encontrada resultado del análisis hermenéutico de las Actas parroquiales porteñas.

Casamientos católicos secretos de funcionarios y militares en Buenos Aires e Hispanoamérica : Intrínseca constitución de algunos de sus matrimonios secretos, de conciencia u ocultos. Siglos XVIII-XIX

El objetivo del trabajo es dar a conocer los casamientos secretos efectuados por la Iglesia Católica a espaldas del Rey y las autoridades virreinales en Buenos Aires; especialmente, de funcionarios y oficiales de las fuerzas terrestres y navales de la monarquía en el siglo XVIII. Los análisis se basan en el Derecho Canónico y lo establecido en el Concilio de Trento (1545-1563). Una variada bibliografía relacionada con la constitución de las familias en Europa e Hispanoamérica permitió explorar un marco desconocido de lo ocurrido con estos matrimonios secretos también llamados de conciencia u ocultos. Se explicitan las características de este tipo de nupcias y la casuística encontrada resultado del análisis hermenéutico de las Actas parroquiales porteñas.

Casamientos católicos secretos de funcionarios y militares en Buenos Aires e Hispanoamérica : Intrínseca constitución de algunos de sus matrimonios secretos, de conciencia u ocultos. Siglos XVIII-XIX

El objetivo del trabajo es dar a conocer los casamientos secretos efectuados por la Iglesia Católica a espaldas del Rey y las autoridades virreinales en Buenos Aires; especialmente, de funcionarios y oficiales de las fuerzas terrestres y navales de la monarquía en el siglo XVIII. Los análisis se basan en el Derecho Canónico y lo establecido en el Concilio de Trento (1545-1563). Una variada bibliografía relacionada con la constitución de las familias en Europa e Hispanoamérica permitió explorar un marco desconocido de lo ocurrido con estos matrimonios secretos también llamados de conciencia u ocultos. Se explicitan las características de este tipo de nupcias y la casuística encontrada resultado del análisis hermenéutico de las Actas parroquiales porteñas.

Polymer Process Partitioning: Extruding Plastic Pipe

When plastic pipe is solidified, it proceeds through a long cooling chamber. Inside this chamber, inside the hollow extrudate, the plastic is molten, and this inner surface solidifies last. Sag, the flow due to the self-weight of the molten plastic, then happens in this cooling chamber, and sometimes, thickened regions (called knuckles) arise in the lower quadrants, especially of large diameter thickwalled pipes. To compensate for sag, engineers normally shift the die centerpiece downward. This thesis focuses on the consequences of this decentering. Specifically, when the molten polymer is viscoelastic, as is normally the case, a downward lateral force is exerted on the mandrel. Die eccentricity also affects the downstream axial force on the mandrel. These forces govern how rigidly the mandrel must be attached (normally, on a spider die). We attack this flow problem in eccentric cylindrical coordinates, using the Oldroyd 8-constant constitutive model framework. Specifically, we revise the method of Jones (1964), called polymer process partitioning. We estimate both axial and lateral forces. We develop a corresponding map to help plastics engineers predict the extrudate shape, including extrudate knuckles. From the mass balance over the postdie region, we then predict the shape of the extrudate entering the cooling chamber. We further include expressions for the stresses in the extruded polymer melt. We include detailed dimensional worked examples to show process engineers how to use our results to design pipe dies, and especially to suppress extrudate knuckling.

The Masculine State in Crisis: War Resistance in Apartheid South Africa

External and internal forces threatened the apartheid state in the 1980s. The refusal to perform compulsory military service by individual white men and the increasing number of white South Africans who criticized the role of the military and apartheid governance had the potential to destabilize the gendered binaries on which white social order and Nationalist rule rested. The state constituted itself as a heterosexual, masculine entity in crisis and deployed a number of gendered discourses in an effort to isolate and negate objectors to military service. The state articulated a nationalist discourse that defined the white community in virile, masculine, and heroic terms. Conversely, “feminine” weakness, cowardice, and compromise were scorned. Objectors, as “strangers” in the public realm, were most vulnerable to homophobic stigmatization from the state and its supporters

FEM Analysis to Optimally Design End Mill cutters for Milling of Ti-6Al-4V

This paper presents an FEM analysis conducted for optimally designing end mill cutters through verifying the cutting tool forces and stresses for milling Titanium alloy Ti-6Al-4 V. Initially, the theoretical tool forces are calculated by considering the cutting edge on a cutting tool as the curve of an intersection over a spherical/flat surface based on the model developed by Lee & Altinas [1]. Considering the lowest tool forces the cutting tool parameters are taken and optimal design of end mill is decided for different sizes. Then the 3D CAD models of the end mills are developed and used for Finite Element Method to verify the cutting forces for milling Ti-6Al-4 V. The cutting tool forces, stress, strain concentration (s), tool wear, and temperature of the cutting tool with the different geometric shapes are simulated considering Ti-6Al-4 V as work piece material. Finally, the simulated and theoretical values are compared and the optimal design of cutting tool for different sizes are validated. The present approach considers to improve the quality of machining surface and tool life with effects of the various parameters concerning the oblique cutting process namely axial, radial and tangential forces. Various simulated test cases are presented to highlight the approach on optimally designing end mill cutters.

Casamientos católicos secretos de funcionarios y militares en Buenos Aires e Hispanoamérica : Intrínseca constitución de algunos de sus matrimonios secretos, de conciencia u ocultos. Siglos XVIII-XIX

El objetivo del trabajo es dar a conocer los casamientos secretos efectuados por la Iglesia Católica a espaldas del Rey y las autoridades virreinales en Buenos Aires; especialmente, de funcionarios y oficiales de las fuerzas terrestres y navales de la monarquía en el siglo XVIII. Los análisis se basan en el Derecho Canónico y lo establecido en el Concilio de Trento (1545-1563). Una variada bibliografía relacionada con la constitución de las familias en Europa e Hispanoamérica permitió explorar un marco desconocido de lo ocurrido con estos matrimonios secretos también llamados de conciencia u ocultos. Se explicitan las características de este tipo de nupcias y la casuística encontrada resultado del análisis hermenéutico de las Actas parroquiales porteñas.