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This article aims to inform the development of biological perchlorate remediation schemes for the preparation of safer human Mars habitats and contaminant-free in situ resource utilization (ISRU) f...

While tensions may lie between science and policy, we argue that dissemination and public engagement are key in alleviating those perceived tensions. Science being valued by society results in fact-based policy-making being demanded by constituents. Constituents’ demands will yield representatives who are familiar with the scientific process and research to inform policy decisions.

OMNICROP uses a database composed of labeled data, such as light quality and quantity, general climate characteristics, and soil quality, from successful farming sites to sort and select the most s...

O crescimento da produção bibliográfica em todas as áreas da ciência é evidente, porém a organização de suas informações ainda é um desafio. Diante disso o trabalho parte de uma proposta em melhorar uma organização da informação, neste caso uma taxonomia, utilizando a análise de redes sociais para auxiliar na gestão e atualização do conhecimento. Sendo assim, desenvolvemos uma metodologia que vai desde a escolha das publicações, definição de uma taxonomia de referência, aplicação de métricas de análise de redes sociais até a recomendação de uma nova taxonomia. Avaliamos o método quantitativamente e qualitativamente, onde obtivemos resultados consistentes e conseguimos recomendar novas formas de organização da informação.

Are you engaged in rigorous science? If so, ask your elected representatives to fund it robustly and predictably and to oppose policies that impede scientific progress.

When the external sheath of flexible pipes experiences damage, seawater floods the annulus. Then, the external pressure is applied directly on the internal polymeric layer, and the load is transferred to the interlocked carcass, the innermost layer. In this situation, the so-called wet collapse failure of the interlocked carcass can occur. Simplified methodologies to address such a scenario, using restricted three-dimensional (3D) finite element models, are presented in this work. They are compared with full 3D models, studying both straight and curved flexible pipes scenarios. The curvature of the flexible pipe is shown to be important for wet collapse pressure predictions.

The connectors on an umbilical system are critical components that are subjected to high tensile loads. To ensure tension resistance to an umbilical cable connection, its structural elements must be properly anchored to the armor pot. One way to provide that connection is the use of the adhesive properties of an epoxy resin. In that context, it is necessary to perform a series of pull out tests in order to verify if the resin is capable of withstanding the tensile loads transmitted by the tensile armor layers or the steel tubes. For that purpose, a series of tridimensional finite element models are being developed to represent, as realistic as possible, the interaction between metallic layer and resin. These models allow a fully helical tensile armor to interact with a resin substrate. For this article, an early stage model considering bonded contacts is presented and the adhesion of the tensile armor tendons is evaluated in terms of the shear stresses in the contact regions.

The analysis of the organization of knowledge is an important tool for the management and evaluation of development agencies. Decisions are made in public politics, investment in research and innovation from the academic production of researchers and educational institutions in different areas of science. In many cases this organization is composed of a rigid structure that does not follow the development of their areas, this affects the progress of science, an example of organization is the taxonomy. With the analysis of the study of social network, we use the collaboration between researchers in a co-authors network can demonstrate new links among knowledge areas. This article describes a method which analyzes a co-authorship network, infers how areas are related and suggests new links and areas for a taxonomy. We applied our method in the IEEE taxonomy, and in our experiments we obtained good update suggestions to this taxonomy, according to the experts.

As grandes revoluções tecnológicas são cíclicas; ocorrem a cada 50 ou 60 anos. A cada iteração, tecnologias antes tidas como infalíveis e definitivas tornam-se obsoletas, dando lugar a novas formas de resolver problemas até então considerados intransponíveis. A revolução tecnológica em curso é a da Tecnologia da Informação e Comunicação, catalisada pela criação de um ambiente aberto e democrático: a Internet. Esta se transforma em uma plataforma ubíqua e permite que empreendedores repensem as dinâmicas sociais e econômicas. Um ecossistema baseado na Lei de Moore, que diz que a capacidade computacional dobra a cada 18 meses sob o mesmo custo, cria uma sensação de inexistência de limites à criatividade. O objetivo deste trabalho é analisar como corporações já estabelecidas, também chamadas de incumbentes, podem se comportar a fim de serem as catalisadoras de inovações nos mercados onde elas mesmas atuam, em vez de esperar que outras empresas o façam. Esta dissertação baseia-se nos princípios da pesquisa qualitativa, utilizando um método essencialmente prescritivo, com o objetivo principal de desenvolver recomendações. Para prover as diretivas, descreve-se a realidade, entendendo os fenômenos de inovação, empreendedorismo, intraempreendedorismo e disrupção digital, assim como as relações entre eventos que os geram ou os influenciam. Empresas incumbentes podem utilizar as recomendações descritas neste trabalho com o intuito de serem proativas na curva de disrupção de mercados, deixando de lado o papel de incumbentes disrompidos para serem protagonistas no processo de disrupção, mantendo a liderança nos mercados onde atuam e tornando-se capazes de vislumbrar novos fluxos de receitas estimulados pela inovação. The great technological revolutions are cyclical; they take place every 50 or 60 years. During each iteration, technologies that were once deemed infallible and definitive become obsolete, giving way for new ways to solve problems once thought insurmountable. The current technological revolution is the Information and Communication one, which is empowered by the creation of an open and democratic environment: the Internet. The Internet is becoming a ubiquitous platform, allowing entrepreneurs to rethink social and economic dynamics. An ecosystem based on Moore’s Law, which states that the computing power doubles every 18 months at the same cost, creates a sensation of lack of limits to creativity. The goal of this work is to analyze how established companies, also called incumbents, should act in order to be the catalysts for innovation in the markets where they operate, rather than waiting for other companies to do so. This dissertation is based on the qualitative research approach and uses an essentially prescriptive method with the main objective to develop recommendations. In order to provide these guidelines, it describes the reality by understanding the phenomena of innovation, entrepreneurship, intrapreneurship and digital disruption, as well as the relationships among the events that generate or influence them. Incumbent companies may utilize the recommendations here described with the purpose of being proactive on the market disruption curve, leaving aside the disrupted incumbent role to become the protagonists on the disruption process, maintaining their market share leadership and also becoming capable of glimpse new revenue streams inspired by innovation.

Dry collapse is one of the possible failure modes of flexible pipes. It refers to the situation in which no damage occurs in the flexible pipe external sheath. In this scenario, all layers of the pipe withstand the external pressure loading in a deep-water application. Such a situation is addressed in this work, which proposes some simplified modeling techniques to represent straight and curved flexible pipes subjected to external pressure, undergoing dry collapse during simulation procedure. The results of the proposed models are compared to other reference results, from a fully three-dimensional (3D) finite element model. Good agreement has been got, even with the proposed simplifications with a large reduction in computational cost when compared to full 3D model.

At the end of flexible pipe manufacturing, the assembly of end fittings ancillaries is necessary to provide the connection with the platform and the subsea systems. The assembly process uses epoxy resin to ensure the holding of the tensile armor layers inside the end fitting. The anchoring system has great importance in the integrity of the flexible pipes system, since their failure causes the separation between the flexible pipe and ancillaries, what can put on risk the production and the environment. During the qualification tests of new structures were observed that some variables of the process could be determinant on the mechanical strength resistance required for the product. One of these known variables is the ratio resin/hardener. Resin supplier specifies at the datasheet the proper ratio to obtain the full cure, but it was observed that small variations in the concentration alters the maximum tensile anchoring strength supported by the structure, as well the minimum curing time that should be obeyed, so it can be better used regarding their mechanical properties. In this way, laboratorial tests were conducted to enhance the performance of this resin in the tensile anchoring system, according to Prysmian Surflex products’ necessity. Compression tests varying the resin/hardener ratio were done to evaluate the resistance as a function of curing time. Besides this, tensile tests (tensile wire pulls over from resin) were conducted to establish a relation between maximum tensile load and the resin ratio, and so provide enough data to control the best proportion of resin during the end fitting assembly phase.Copyright © 2015 by ASME

Umbilical cables are essential elements of offshore floating production systems. Due to their complexity, the offshore industry regularly counts on numerical tools to perform design assignments. One of these assignments is to evaluate strains and stresses states in all components due to distinct sets of external loads. The main purpose of this paper is to present a numerical model for prediction of the stress and strain fields in the umbilical cable components under crushing loads. Such loads, outcoming from the laying operation, comprise the caterpillar shoes load and the squeezing effects, associated not only to the tensile armours, but also to helical components under tension. The referred model comprises a joint analysis using a two-dimensional Finite Element Method (FEM) fed by an analytical model, which represent three-dimensional effects. A combined analytical-numerical approach is much easier to implement than a complete fully three-dimensional one and it is meant to obtain results efficiently, without the need of a large computational capacity. The paper presents and discuss modeling hypotheses and methodology, describing in which way three-dimensional effects and interactions among cable components were treated. Case studies with three umbilical cables are presented.Copyright © 2015 by ASME

In the design of flexible pipes, predict the anchoring behavior on end fittings is always challenging. In this sense, Prysmian Surflex has developed a finite element model, which should help the end fitting design as well the prediction of the structural behavior and the acceptable maximum loads. The current model considers that the contact between armor-resin is purely cohesive and has been suitable for the design of end fittings [1] and [2]. But tests and new studies [3] and [4] indicate that only cohesive assumption would not be the best approach. Experimental data from prototype tests also show that the current model would not predict acceptable results for loads higher than those used in previous projects. This document will describe a study developed considering the friction and thermal contraction, instead of the cohesive phenomenon in the anchoring behavior analysis. Small scale tests were conducted in order to understand the anchoring relation between the resin and the wire used in the tensile armor. For this purpose, a special test device was developed to simulate an enclosure system. A parametric study was also performed to identify the cooling temperatures, coefficients of friction and contact properties parameters taken from small scale tests. The finite element model considers the thermal effects during exothermic curing. Using the new parameters obtained, a second model was developed. This model consists of only one real shaped bended wire inside an end fitting cavity. To validate the model, samples were tested on laboratory according anchoring design. The results of this round of tests were studied and corroborate the argument that use friction and thermal effects is better than use only the cohesive condition.

Recentes descobertas a respeito de uma das farsas mais icônicas do teatro brasileiro são expostas nesse ensaio, a fim de propor novas reflexões acerca de sua elaboração. A partir da análise dos artigos de Darcy Damasceno, o principal pesquisador de Martins Pena, encontramos uma série de informações que nos permitem ampliar a compreensão sobre a peça. Além disso, ao consultar a coletânea de Martins Pena no acervo de Darcy Damasceno, encontramos algumas anotações que revelam suas últimas interpretações, o que inclui trechos antes desconhecidos.

Esta resenha apresenta o primeiro romance de Luisa Geisler como uma construção meticulosa. Afirma ser raro encontrar ficcionista tão afinado com o gênero, mesmo entre aqueles com mais prática. Consciente das finalidades da obra literária, Quiçá é dotado de enorme capacidade para abranger variados horizontes de leitura e fruição estética. Deve ser visto como narrativa de estreia, mas também como filho vigoroso, daqueles que nascem como o referencial exigente de um conjunto literário -- algo para os próximos irmãos confirmarem.

This paper presents a numerical 3D finite element model to simulate a flexible pipe under crushing-traction condition, which is a typical situation found during its laying operation. This model considers the geometry of some layers from the flexible pipe, responsible of providing the most contribution to its radial strength (e.g., interlocked carcass, internal polymeric layer, pressure armor, and external polymeric layer) and geometry of laying system shoes. It also considers the flexible pipe initial ovalization and the squeezing effect due to the tensile armor layers under traction. A numerical-experimental comparison is presented, in order to show the model validity.Copyright © 2013 by ASME

Accurate prediction of the load capacity of the constituent components of flexible risers and flowline structures is critical in demonstrating fitness for purpose, particularly as the envelope of application of flexible pipe is being extended to incorporate higher flow rates, greater water depths, more aggressive fluid contents and challenging installation conditions. Analytical techniques and numerical solid modelling methods have evolved significantly in recent years as a means of improving the ability to accurately predict flexible pipe load capacity. Due to the complexity of the flexible pipe structure and the load sources and load paths to which it can be subjected, different analysis methods are required, depending on the type of response being evaluated. Specific effects can be difficult to simulate using analytical approaches and require local stress analysis using numerical techniques. This paper presents numerical approaches to two such effects, the extreme loading of tensile armour wires within a flexible pipe end fitting and the stability of tensile armour wires in axial compression.

This paper discusses a nonlinear analytical model for flexible pipe crushing analysis, improving analytical models previously published in OMAE2003, 2010 and 2011. Following that path, and still based on the concept of equivalent pipes and rings, the present model discusses a strategy to cope with an elastic-to-plastic analysis. Such a model considers the combined action of squeezing and concentrated loads applied as representing those due to the caterpillar shoes. Experimental results and finite element analysis are used to assess the pertinence of analytical modeling hypotheses.Copyright © 2012 by ASME

During installation and operation a flexible pipe may be subjected to high compressive forces, high cyclic curvatures and external pressures leading to high reverse end-cap loads. Under such loading conditions, which occur particularly in the touchdown region for deep water applications, the limiting condition for the flexible pipe can be the compressive stability of the tensile armour wires. Two potential instability modes are possible: radial mode (birdcaging) and lateral mode (lateral wire disorganization). Previous work on the subject has established the key factors which influence the onset of each buckling mode [1],[2],[3] and [4]. In order to ensure the feasibility of flexible designs for applications with increasing water depth, it is important to improve the knowledge of the mechanisms which can lead to instability of armour wires and enhance the ability to predict with greater assurance, the particular conditions which increase the risk of wire instability. The focus of this work is the comparison of finite element prediction of radial buckling (birdcaging) with physical testing results under loading states that lead a pipe to birdcaging failure. The numerical model incorporates all tensile armor wires and their interactions with each other and adjacent layers. The outer sheath and reinforcing tape layers are explicitly represented, while the inner layers of the pipe (pressure armour and carcass sheath) are idealized using a homogeneous representation. The model also incorporates the effects of manufacturing pre-tension and hoop strength in the anti-birdcaging tape layers which are critical determinants for the onset of buckling. A key aspect of the method presented is the means by which the loading is applied. Specifically, the modeling handles the simultaneous and controlled application of end rotations, axial compression and radial resistance of the tapes through to the point of tape failure, pipe ovalisation and subsequent radial displacement and buckling of individual wires. In summary, in this paper a solid modeling approach is presented, which is compared with full a scale sample test data, that enables the simulation of a flexible pipe undergoing large combined compression, curvatures and pressure loading.

Abstract A new optical measurement approach for minimum bending radius (MBR) tests of flexible pipes is presented. The method is based on an accurate tracking of the elastica through image processing. The new approach shows to be not only appropriate to the standard measurement requirements but also enables a comprehensive understanding of the structural mechanisms embedded in the problem. Samples were made from two distinct flexible pipes, with inner diameters of 2.5 and 4 inches. A progressive set of tests was performed using five types of samples, obtained by dissecting each flexible pipe up to a certain layer. Sample 1 is made up with the internal carcass only. Sample 2 is constructed up to the liner (the internal plastic sheath covering the carcass). Sample 3 is mounted up to the pressure armor. Sample 4 is manufactured up to the external tensile armor. Sample 5 is made from the entire pipe, up to the external polymeric sheath. The experimental methodology is given in detail. The samples are bent through the pulling of a cable linked to the extremities. The traction is measured by a load cell. A special stereoscopic system is used to optically obtain the geometry of the elastic line of the bent sample. From the measured elastica, the curvature is calculated. Results of bending moment at any section may be also calculated from the elastic line. In particular, bending moment vs. curvature, measured at the vertex of the arch, are calculated for each sample. Introduction Flexible Pipes are increasingly used for the transport of oil & gas, due to their flexibility, reliability and high resistance to the several types of loads inherent to this type of application. These loads include high pressures, both internal and external, tensions and curvatures and the flexible pipe resistance to these different loads is obtained by a construction with many component layers, each one responsible for the resistance to a given load (See Figure 2 for the different layers, represented by the different samples used in the test). Since they are slender structures, a significant amount of bending is induced during their operation and must be taken into account in its design. This paper describes an experimental methodology to relate bending moment and imposed curvature, which is specially suited for the validation of a design methodology, since its results allow the developer of such methodology to have insights into details of the mechanical behavior of the tested structure, on a layer-by-layer basis. The test was applied to obtain the maximum curvatures that different layers of two flexible pipes can reach without damage.

Despite global analysis of umbilicals is a well-known area in the offshore systems design, some topics are still opened for discussions. One of these topics refers to the structural damping. Obviously, the viscous damping caused by hydrodynamic drag forces is the major source of damping to the whole system. However, in some severe load cases, the host vessel dynamics may induce high snatch loads to the umbilical top end and these loads are more related to structural damping, specifically in tension–elongation hysteresis, than to viscous damping. The snatch loads must be taken into account in the whole design process, which leads to an umbilical designed to resist to higher tension loads and implies also, in most cases, in over-dimensioned accessories, such as the bending limiters. Actually, due to the high level of friction between layers, the umbilical presents some level of structural damping which is, in fact, related to hysteretic moment-curvature and tension-elongation relations. This intrinsic structural damping may in fact contribute to the reduction of the snatch loads and considering it may reduce the level of conservatism in the design. However, due to the complexity and diversity of umbilical designs, it is not straightforward to come up with general-use hysteretic curves. A simplification then is to apply classic Rayleigh damping. Typically, damping levels of 5% are accepted in the offshore industry when using stiffness-proportional Rayleigh damping (the 5% damping is a percentage of the critical damping and is accounted for at the regular wave period or irregular wave spectral peak period). The problem here is that stiffness-proportional Rayleigh damping increases linearly with the frequency and the damping level at 1Hz, for example, may get to 60%. This fact indicates that the high-frequency part of the response may be simply discarded from the results, which in turn may lead to an incorrect, over-damped analysis. The present work aims tackling the Rayleigh damping issue, evaluating its effects on tension levels and spectral density of the tension time history. A recommendation of how to apply Rayleigh damping is proposed.

The paper presents a theoretical-experimental comparison concerning standard crushing-traction tests of flexible pipe prototypes. The theoretical model for crushing is analytical and based on classic assumptions of equivalent pipes, applying model previously published in OMAE2003, and OMAE2010. Such a model considers the combined action of squeezing, concentrated loads due to the caterpillar shoes as well as the effect of initial ovalization. The experimental measures include a detailed internal geometrical mapping of the deformed carcass, until plastic deformation becomes evident. Discussion is made on the pertinence of modeling hypotheses. Sensitivity analyses, regarding initial ovalization and helical pitch of the pressure armor are also addressed.Copyright © 2011 by ASME

Umbilicals for offshore application are very complex, since they combine elements of different mechanical behavior, such as steel tubes, thermoplastic hoses and power cores in a single structure, not to mention helically laid-up armouring layers and polymeric sheathes. This motivates continuous research on their mechanical modeling. This paper presents research undertaken in the structural behavior of umbilicals and focus on the mathematical modeling of the elements, which are gathered into concentric layers. Interaction between layers is included as well as helical lay-up of elements. The model here presented will be compared to a set of experimental results in a separate paper (Part II). An analytical model was developed combining equilibrium equations, geometric compatibility and constitutive relations to obtain a set of equations that describe the umbilical behavior under external loads. This set of equations is numerically solved to obtain contact pressures (or gaps) among layers, radial variations and strains in the elements (used to calculate the stresses). The model was built to be general in order to be able to cope with complex cross-sections designs often encountered. It was then implemented in a tailor made local analysis software, called UTILFLEX®. Both modeling and software resulted from a development program partnership between Prysmian Cables & Systems and University of Sao Paulo. The paper will present modeling hypotheses and structural models that were used for steel tubes, hoses (thermoplastic and reinforced) and power cables and how the interaction among them has been treated.Copyright © 2010 by ASME