bluuebunny/crossref_metadata_2025 huggingface dataset:
ITIM‐dependent negative signaling pathways for the control of cell‐mediated xenogeneic immune responses
Authors: del Rio Maria‐Luisa , Seebach Jörg D. , Fernández‐Renedo Carlos , Rodriguez‐Barbosa Jose‐Ignacio
Published: August 2013

Xenotransplantation is an innovative field of research with the potential to provide us with an alternative source of organs to face the severe shortage of human organ donors. For several reasons, pigs have been chosen as the most suitable source of organs and tissues for transplantation in humans. However, porcine xenografts undergo cellular immune responses representing a major barrier to their acceptance and normal functioning. Innate and adaptive xenogeneic immunity is mediated by both the recognition of xenogeneic tissue antigens and the lack of inhibition due to molecular cross‐species incompatibilities of regulatory pathways. Therefore, the delivery of immunoreceptor tyrosine‐based inhibitory motif (ITIM)‐dependent and related negative signals to control innate (NK cells, macrophages) and adaptive T and B cells might overcome cell‐mediated xenogeneic immunity. The proof of this concept has already been achieved in vitro by the transgenic overexpression of human ligands of several inhibitory receptors in porcine cells resulting in their resistance against xenoreactivity. Consequently, several transgenic pigs expressing tissue‐specific human ligands of inhibitory coreceptors (HLA‐E, CD47) or soluble competitors of costimulation (belatacept) have already been generated. The development of these robust and innovative approaches to modulate human anti‐pig cellular immune responses, complementary to conventional immunosuppression, will help to achieve long‐term xenograft survival. In this review, we will focus on the current strategies to enhance negative signaling pathways for the regulation of undesirable cell‐mediated xenoreactive immune responses.
ISLAM AND BIOETHICS IN THE CONTEXT OF “RELIGION AND SCIENCE”
Authors: Drees Willem B.
Published: August 2013

This paper places “Islam and bioethics” within the framework of “religion and science” discourse. It thus may be seen as a complement to the paper by Henk ten Have () with which this thematic section in Zygon: Journal of Religion and Science opens, which places “Islam and bioethics” in the context of contemporary bioethics. It turns out that in Zygon there have been more submitted articles on Islam and bioethics than on any other Islam‐related topic. This may be a consequence of the global nature of the bioethical issues, driven by advancement in science and technology, which allows for conversation across cultural and religious boundaries even when the normative references and argumentative methods are tradition‐specific.
GORDON KAUFMAN, FLAT ONTOLOGY, AND VALUE: TOWARD AN ECOLOGICAL THEOCENTRISM
Authors: James Thomas A.
Published: August 2013

Gordon Kaufman's theology is characterized by a heightened tension between transcendence, expressed as theocentrism, and immanence, expressed as theological naturalism. The interplay between these two motifs leads to a contradiction between an austerity created by the conjunction of naturalism and theocentrism, on the one hand, and a humanized cosmos which is characterized by a pivotal and unique role for human moral agency, on the other. This paper tracks some of the influences behind Kaufman's program (primarily H. Richard Niebuhr and Henry Nelson Wieman) and then utilizes the flat ontology that emerges in the work of philosopher/sociologist of science Bruno Latour and of environmental philosopher Timothy Morton in order to point toward a reconstructed immanent theocentrism that no longer stakes meaning and value on the unique place of the human. Such a theology remains theocentric, but is now fully ecological.
A CHRISTIAN NATURALISM: DEVELOPING THE THINKING OF GORDON KAUFMAN
Authors: Peters Karl E.
Published: August 2013

This essay develops a theological naturalism using Gordon Kaufman's nonpersonal idea of God as serendipitous creativity in contrast to the personal metaphorical theology of Sallie McFague. It then develops a Christian theological naturalism by using Kaufman's idea of historical trajectories, specifically Jesus trajectory1and Jesus trajectory2. The first is the trajectory in the early Christian church assuming a personal God in the framework of Greek philosophy that results in the Trinity. The second is the naturalistic‐humanistic trajectory of creativity (God) that evolves from nonpersonal interactions in the universe and life to creativity in persons and is manifested in Jesus as love. This is elaborated further with Dean Keith Simonton's Darwinian understanding of genius and Marcus Borg's analysis of Jesus as Jewish mystic, teacher of alternative wisdom, and nonviolent resister to the domination system of the Roman Empire. What makes Jesus a religious genius is his exemplifying unconditional, universal love—a new mode of creativity (God) that has evolved from nonhuman to a human form.
EMBODIED COGNITION, CHARACTER FORMATION, AND VIRTUE
Authors: Brown Warren S. , Reimer Kevin S.
Published: August 2013

The theory of embodied cognition makes the claim that our cognitive processes are, at their core, sensorimotor, situated, and action‐relevant. Our mental system is built primarily to control action, and so mind is formed by the nature of the body and its interactions with the world. In this paper we will explore the nature of virtue and its formation from the perspective of embodied cognition. We specifically describe exemplars of the virtue of compassion (caregivers of individuals with developmental disabilities in L'Arche communities), speculating as to what might have been the formative influences in their character development. Embodied formation is understood in the context of the openness of human cortical systems to formation by social interactions, and in terms of the openness to reorganization and change of complex dynamical systems. Specific formative influences explored include interpersonal imitation, social attachment, language, and story.
EMBODIED COGNITION AND RELIGION
Authors: Watts Fraser
Published: August 2013

It is argued that there are good scientific grounds for accepting that cognition functions in a way that reflects embodiment. This represents a more holistic, systemic way of thinking about human beings, and contributes to the coordination of scientific assumptions about mind and body with those of the faith traditions, moving us beyond sterile debates about reductionism. It has been claimed by Francisco Varela and others that there is an affinity between Buddhism and embodied cognition, though it is argued here that they are less closely aligned than is sometimes assumed. Embodied cognition also accords well with the holistic strand of thinking about human nature in Judeo‐Christian thinking. While accepting the persuasiveness of the general case for cognition being embodied it is suggested here that some forms of cognition are more embodied than others, and that it may be one of the distinctive features of humans that they have developed a capacity for relatively nonembodied forms of cognition.
GORDON KAUFMAN'S HUMANIZING CONCEPT OF GOD
Authors: Renaud Myriam
Published: August 2013

Why should Gordon Kaufman's mid‐career theological method be of renewed interest to contemporary theists? Two distinguishing characteristics of the West today are its increasing religious pluralism and the growing numbers of theists who rely on hybrid approaches to construct concepts of God. Kaufman's method is well suited to this current state of affairs because it is open to diverse religious and theological perspectives and to perspectives from science and secular humanism. It also militates against the weaknesses inherent to hybrid approaches—ad hoc constructs of God unable to motivate their holders to overcome human self‐centeredness and so to contribute to the well‐being and fulfillment of others. It achieves this by providing checks to reduce the risk of producing human‐writ‐large God‐constructs. Lastly, Kaufman's method provides criteria to help theists identify humane and humanizing experiences, relationships, concepts, images, and texts (i.e., the basic material from which God‐constructs are fashioned) from the plethora of options available, whether religious, cultural, or secular.
KAUFMAN'S DEBT TO KANT: THE EPISTEMOLOGICAL IMPORTANCE OF THE “STRUCTURE OF THE WORLD WHICH ENVIRONS US”
Authors: Woolley J. Patrick
Published: August 2013

Gordon Kaufman's “constructive theology” can easily be taken out of context and misunderstood or misrepresented as a denial of God. It is too easily overlooked that in his approach everything is an imaginary construct given no immediate ontological status—the self, the world, and God are “products of the imagination.” This reflects an influence, not only of theories on linguistic and cultural relativism, but also of Kant's “ideas of pure reason.” Kaufman is explicit about this debt to Kant. But I argue there are other aspects of Kant's legacy implicit in his method. These center around Kaufman's engagement with “observed patterns” in nature. With Paul Tillich's aid, I bring this neglected issue to the fore and argue that addressing it allows one to more readily capitalize upon the Kantian influence in Kaufman's method. This, in turn, encourages one to tap more deeply into the epistemic underpinnings of Kaufman's approach to the science–religion dialogue.
COLLECTIVE RELIGIO‐SCIENTIFIC DISCUSSIONS ON ISLAM AND HIV/AIDS: I. BIOMEDICAL SCIENTISTS
Authors: Ghaly Mohammed
Published: August 2013

During the 1990s, biomedical scientists and Muslim religious scholars collaborated to construe Islamic responses for the ethical questions raised by the AIDS pandemic. This is the first of a two‐part study examining this collective legal reasoning (ijtihād jamā‘ī). The main thesis is that the role of the biomedical scientists is not limited to presenting scientific information. They engaged in the human rights discourse pertinent to people living with HIV/AIDS, gave an account of the preventive strategy adopted by the World Health Organization, and offered an (Islamic) virtue‐based preventive model. Finally, these scientists tried to draft a number of Islamic legal rulings (aḥkām), usually seen in Islamic jurisprudence as the exclusive business of Muslim religious scholars. This multilayered role played by the scientists reflects intriguing developments in the Islamic religio‐ethical discourse in general and in the field of Islamic jurisprudence in particular.
ISLAMIC VERDICTS IN HEALTH POLICY DISCOURSE: PORCINE‐BASED VACCINES AS A CASE STUDY
Authors: Padela Aasim I.
Published: August 2013

In this article, I apply a policy‐oriented applied Islamic bioethics lens to two verdicts on the permissibility of using vaccines with porcine components. I begin by reviewing the decrees and then proceed to describe how they were used by health policy stakeholders. Subsequently, My analysis will highlight aspects of the verdict's ethico‐legal arguments in order to illustrate salient legal concepts that must be accounted for when using Islamic verdicts as the basis for health policy. I will conclude with several suggestions for facilitating a more judicious use of verdicts in policy‐relevant discourse. My analysis is meant to contribute to the dialogue between science and religion, and aims to further efforts at developing health policies that value health while accommodating religious values. In the encounter between the Islamic tradition and global public health, a multidisciplinary dialogue, where Islamic legists become aware of the health policy implications of their ethico‐legal pronouncements, and where health policy actors gain a literate understanding of Islamic ethico‐legal theory, will lead to verdicts that better meet the needs of patients, health workers, and religious leaders.
WOMB TRANSPLANTATION AND THE INTERPLAY OF ISLAM AND THE WEST
Authors: Alghrani Amel
Published: August 2013

In Saudi Arabia in 2000 the world's first human uterus transplant was attempted with some success. In 2011 the second successful human uterus transplant took place in Turkey. Doctors in the United Kingdom have recently announced that uterus transplants will be carried out in the UK if doctors can raise enough funds to complete their research. As scientists continue to make progress in this domain this is anticipated to be the next breakthrough in the arena of assisted reproductive technologies. The procedure is designed to restore fertility in women unable to gestate due to an abnormal, damaged, or absent uterus. At present, the only other option for such women to achieve genetic motherhood is via surrogacy, which in Islam is widely regarded as haram or forbidden. This article examines the benefits of this technology so as to facilitate discourse between Islam and the West. It argues for Islamic scholars to consider these advances so as to ensure Muslims living as minorities in Western countries, such as the United Kingdom, are able to utilize such technology (if indeed regarded as permissible) should the government move to enact legislation to permit this procedure.
THE INTERPLAY BETWEEN RELIGIOUS LEADERS AND ORGAN DONATION AMONG MUSLIMS
Authors: Rasheed Shoaib A. , Padela Aasim I.
Published: August 2013

Bioethics and health researchers often turn to Islamic jurisconsults (fuqahā’) and their verdicts (fatāwā) to understand how Islam and health intersect. Yet when using fatwā to promote health behavior change, researchers have often found less than ideal results. In this article we examine several health behavior change interventions that partnered with Muslim religious leaders aiming at promoting organ donation. As these efforts have generally met with limited success, we reanalyze these efforts through the lens of the theory of planned behavior, and in light of two distinct scholarly imperatives of Muslim religious leaders, the ʿilmī and the islāhī. We argue for a new approach to health behavior change interventions within the Muslim community that are grounded in theoretical frameworks from the science of behavior change, as well the religious leadership paradigms innate to the Islamic tradition. We conclude by exploring the implications of our proposed model for applied Islamic bioethics and health research.
Udwadia-Kalaba Approach for Parallel Manipulator Dynamics
Authors: Huang Jin , Chen Y. H. , Zhong Zhihua
Published: August 2013

A novel Udwadia-Kalaba approach for parallel manipulator dynamics analysis is presented. The approach segments a parallel manipulator system into several leg-subsystems and the platform subsystem, which are connected by kinematic constraints. The Udwadia-Kalaba equation is then used to calculate the constraint forces due to the constraints. Based on this, the equation of motion, which is an explicit (i.e., closed) form, can be formulated. The method allows a systematic procedure to generate the dynamic model for both direct dynamics and inverse dynamics without invoking additional variables (such as multipliers or quasi-variables), nor does it require projection. A classical parallel Stewart-Gough platform is chosen to demonstrate the feasibility and advantages of this approach.
Robust Filtering for Ammonia Coverage Estimation in Diesel Engine Selective Catalytic Reduction Systems
Authors: Zhang Hui , Wang Junmin , Wang Yue-Yun
Published: August 2013

In this paper, we investigate the nonlinear observer designs to estimate the ammonia coverage ratio in the diesel engine selective catalytic reduction (SCR) systems. The ammonia coverage ratio is an important variable due to its critical role in the SCR NOx conversion and the ammonia slip. However, the ammonia coverage ratio cannot be directly measured by onboard sensors. Therefore, it is necessary to develop effective observers to estimate the ammonia coverage ratio online. Based on a three-state SCR model, we develop two nonlinear observers. The first one only employs the dynamics of the ammonia concentration. The structure and the algorithm are simple. But it is sensitive to the measurement noises and the uncertainties in the system parameters. The second one is a discrete-time smooth variable structure estimator which is robust to the measurement noises, the approximation error, and the system uncertainties. Both estimators are implemented on a full-vehicle simulation of the FTP75 test cycle. The simulation results have verified the theoretical analysis.
Using Leakage to Stabilize a Hydraulic Circuit for Pump Controlled Actuators
Authors: Wang Longke , Book Wayne J.
Published: August 2013

Pump controlled hydraulic actuators offer higher energy efficiency than valve controlled actuators. However, there exists mode switching in pump controlled systems and instability may arise when a single rod cylinder is implemented. This paper examines the problem of system stability in a pump controlled system with single rod cylinders. It is shown that the system dynamics have a stable tendency or an instable tendency corresponding to different cylinder movements. The paper shows system instability can be avoided by controlling fluid leakage, and two applicable methods are presented: physical leakage compensation and virtual leakage compensation, which can be applied depending on applications. Experiments and numerical simulations are presented. Results show that the proposed solutions can maintain circuit stability: physical leakage compensation can be a general approach while virtual leakage compensation offers higher energy efficiency and lower cost, but its applications are limited by some factors.
On the Role of Autonomous Control in Organ Development
Authors: Ramasubramanian Ashok
Published: August 2013

Developmental biology (“development” for short) deals with how the mature animal or plant results from a single fertilized cell. This paper is concerned with one aspect of development, morphogenesis—the formation of complex shapes from simpler ones. In particular, this paper focuses on organ development and illustrates the central role that mechanical feedback plays in effecting the final shape of various organs. The first aim of this paper is to illustrate how self-governing autonomous control systems can lead to the development of organs such as the heart. Although feedback plays a key role in these processes, the field is largely unexplored by controls engineers; hence, the second aim of this paper is to introduce mechanical feedback during development to controls engineers and suggest avenues for future research.
Robust Observer Based Control for Stability of Linear Systems: Application to Polytopic Systems
Authors: Belguith Mouna , Benabdallah Amel
Published: August 2013

This paper investigates the problem of global stabilization by output feedback for linear time-invariant systems. We give first a procedure to design a robust observer for the linear system. Then using this robust observer with the robust state feedback control law developed by Molander and Willems (1980, “Synthesis of State Feedback Control Laws With a Specified Gain and Phase Margin,” IEEE Trans. Autom. Control, 25(5), pp. 928–931), we construct an output feedback which yields a closed loop system with robustness characteristics. That is, we establish a separation principle. Finally, we give sufficient conditions to establish a robust output feedback for linear polytopic systems.
Free Convection in Antisymmetrically Heated Vertical Channels
Authors: Roeleveld D. , Naylor D. , Leong W. H.
Published: August 2013

Free convection in a vertical channel with antisymmetrical heating is a special case that has not received a great deal of attention in the literature. Antisymmetrical heating is where the hot wall is heated above the ambient temperature by the same amount that the cold wall is cooled below the ambient, giving equal but opposing buoyancy forces inside the channel. An experimental model was constructed to study antisymmetrical heating inside an isothermally heated vertical channel. Flow visualization was used to obtain the flow field and laser interferometry was used to obtain the temperature field. Based on the measured temperature field, the local and average Nusselt numbers were determined, which were compared with numerical predictions obtained using ansys fluent. A range of Rayleigh numbers were studied for air with a Prandtl number of 0.71. The results show that an open-ended channel with antisymmetrical heating has some similarities to a tall enclosure. The average convective heat transfer can be approximated using an existing correlation for a tall enclosure from the literature.
Effects of Hydrostatic Stress and Concentration-Dependent Elastic Modulus on Diffusion-Induced Stresses in Cylindrical Li-Ion Batteries
Authors: Guo Zhansheng , Zhang Tao , Hu Hongjiu , Song Yicheng , Zhang Junqian
Published: August 2013

The effects of hydrostatic stress and concentration-dependent elastic modulus on diffusion-induced stress (DIS) in a cylindrical Li-ion battery are studied. It is found that the hydrostatic stress has little effect on the distribution of stresses but the change of elastic modulus has a significant effect on the distribution of stresses. The hydrostatic stress has little effect on the location of maximum hoop stress in active layer. The change of elastic modulus can slow down the trend with closing to the inner surface for the location of the maximum hoop stress in active layer with the thicker current collector or larger modulus of current collector and speed up the trend with closing to the outer surface with the smaller ratio of electrode radius to thickness. The current collector should be as thin and soft as possible when its premise strength is satisfied. The ratio of electrode radius to thickness should be preferably larger than 15.
Rate Dependent Adhesion Energy and Nonsteady Peeling of Inextensible Tapes
Authors: Kovalchick Christopher , Molinari Alain , Ravichandran Guruswami
Published: August 2013

Elastomer based pressure sensitive adhesives used in various peeling applications are viscoelastic and expected to be rate sensitive. The effects of varying peel velocity on adhesion energy and its dependence on the peel angle and rate of peeling are investigated. Experiments are conducted on an adhesive tape using a displacement-controlled peel test configuration. By adjusting the peel arm length, the peel velocity can be continuously varied though the extremity of the film is displaced at a constant rate, which results in nonsteady peeling. Constant peel rate tests are performed over a wide range of peeling rates for a fixed peeling angle, which results in steady state peeling. Based upon the experimental data, a power law relation for the adhesive energy of a packaging tape and its dependence on the rate of peeling is presented. The applicability of the rate dependent law for adhesion energy based upon the steady state experiments to the nonsteady peeling process is critically examined.
Multirow Film Cooling Performances of a High Lift Blade and Vane
Authors: Naik S. , Krueckels J. , Gritsch M. , Schnieder M.
Published: August 2013

This paper investigates the aerodynamic and film cooling effectiveness characteristics of a first stage turbine high lift guide vane and its corresponding downstream blade. The vane and blade geometrical profiles and operating conditions are representative of that normally found in a heavy-duty gas turbine. Both the vane and the blade airfoils consist of multirow film cooling holes located at various axial positions along the airfoil chord. The film cooling holes are geometrically three-dimensional in shape and depending on the location on the airfoil, they can be either symmetrically fan shaped or nonsymmetrically fan shaped. Additionally the film cooling holes can be either compounded or in-line with the external flow direction. Numerical studies and experimental investigations in a linear cascade have been conducted at vane and blade exit isentropic Mach number of 0.8. The influence of the coolant flow ejected from the film cooling holes has been investigated for both the vane and the blade profiles. For the nozzle guide vane, the measured film cooling effectiveness compared well with the predictions, especially on the pressure side. The suction side film cooling effectiveness, which consisted of two prethroat film rows, proved very effective up to the suction side trailing edge. For the blade, there was a reasonable comparison between the measured and predicted film cooling effectiveness. Again the blade prethroat fan shaped cooling holes proved very effective up to the suction side trailing edge. For the vane, the impact of varying the blowing ratios showed a strong variation in the film cooling effectiveness on the pressure side. However, on the blade, the effect of varying the blowing ratio had a greater impact on the suction side film effectiveness compared to the pressure side.
2D Elastodynamic Solution for the Impact Response of Laminated Composites
Authors: Xie Jiawen , Waas Anthony M.
Published: August 2013

This paper presents a general, exact, two-dimensional (2D) elastodynamic analysis of the response of laminated composite panels subjected to transverse impact loading under conditions of planar deformation. The natural frequencies and mode shapes of free vibration are first extracted. Inspired by a transformation technique for solving a special class of partial differential equations, the forced vibration problem of an impacted laminated panel is solved using an eigenfunction expansion technique. Several examples are studied by varying the laminate lay-up and length-to-thickness ratio. The distributions of transverse stresses in the through-the-thickness direction are further compared with two one-dimensional theories, classical lamination theory (CLT) and first-order shear deformation theory (FSDT), showing the inadequacy of these theories and the necessity to establish a benchmark solution for 2D elastodynamics. The 2D elastodynamic theory that is formulated is also applicable for studying other multilayered structures subjected to arbitrary loading profiles.
Modal Selection Through Effective Interface Mass With Application to Flexible Multibody Cranktrain Dynamics
Authors: Ricci S. , Troncossi M. , Rivola A.
Published: August 2013

The development of a multibody model of a motorbike L-twin engine cranktrain is presented in this work. The need for an accurate evaluation of the loads acting on the main engine components at high rotational speed makes it necessary to take element flexibility into account in order to capture elastodynamic effects, which might have a major impact on the dynamics of the system. Starting from finite element descriptions of both the crankshaft and the connecting rod, the classical Craig–Bampton (CB) technique is employed to obtain reduced models, which are suitable for the subsequent multibody analysis. A particular component mode selection procedure is implemented based on the concept of effective interface mass, allowing an assessment of the accuracy of the reduced model prior to the nonlinear simulation phase. Bearing dynamics also plays an important role in such a high-speed engine application: angular contact ball bearings are modeled according to a 5DOF nonlinear scheme in order to grasp the main bearings behavior while an impedance-based hydrodynamic bearing model is implemented providing an enhanced operation prediction at big end locations. The assembled cranktrain model is simulated using a commercial multibody software platform. Numerical results demonstrate the effectiveness of the procedure implemented for the flexible component model reduction. The advantages of this technique over the traditional mode truncation approach are discussed.
Structural and Continuum Mechanics Approaches for a 3D Shear Deformable ANCF Beam Finite Element: Application to Buckling and Nonlinear Dynamic Examples
Authors: Nachbagauer Karin , Gerstmayr Johannes
Published: August 2013

For the modeling of large deformations in multibody dynamics problems, the absolute nodal coordinate formulation (ANCF) is advantageous since in general, the ANCF leads to a constant mass matrix. The proposed ANCF beam finite elements in this approach use the transverse slope vectors for the parameterization of the orientation of the cross section and do not employ an axial nodal slope vector. The geometric description, the degrees of freedom, and a continuum-mechanics-based and a structural-mechanics-based formulation for the elastic forces of the beam finite elements, as well as their usage in several static problems, have been presented in a previous work. A comparison to results provided in the literature to analytical solution and to the solution found by commercial finite element software shows accuracy and high order convergence in statics. The main subject of the present paper is to show the usability of the beam finite elements in dynamic and buckling applications.
Effect of the Hydrostatic Pressure in the Diffusible Hydrogen at the Underwater Wet Welding
Authors: da Silva Weslley Carlos Dias , Ribeiro Leandro Fonseca , Bracarense Alexandre Queiroz , Pessoa Ezequiel Caires Pereira
Published: August 2013

The underwater wet welding using SMAW is widely used in maintenance and repairs of submerged structures. In this process, water can dissociate, providing substantial quantities of ions H+ and O2− at the molten pool. Hydrogen and oxygen may constitute gas bubbles in the molten weld metal which may result in formation of pores. The hydrogen can diffuse by the weld metal and heat-affected zone or be trapped in the structure of the weld metal in the form of residual hydrogen. The diffusible hydrogen in the weld metal and heat-affected zone might have a deleterious effect in the mechanical properties of welded joint. The diffusible hydrogen plus susceptible microstructure, such as martensite, presence of tensile residual tension and temperatures lower than 200°C can lead the arising of cracks in the weld metal and heat-affected zone. All these conditions are satisfied in underwater wet welding. The amount of diffusible hydrogen in the weld metal can be influenced by several factors. However, it is not yet known whether the depth of welding (pressure) affects the amount of diffusible hydrogen in weld metal. In this work, several measurements of diffusible hydrogen were made at following depth: 0.30m, 10m, 20m and 30m at wet welding. The electrode used was commercial waterproofed E6013. The diffusible hydrogen measurements were made through the gas chromatography method following the AWS D3.6M procedure. The porosity was measured using the macrographic method and a software called Quantikov. The weld bead reinforcement and width were also measured. The residual hydrogen also was measured. The results showed that diffusible hydrogen reduced substantially as the hydrostatic pressure increased. The porosity, as it was related previously, increased as the hydrostatic pressure increased. Changes in the residual hydrogen of the weld metal were not observed. So, it was possible to conclude that the welding depth affects directly the diffusible hydrogen and porosity levels of underwater wet welds.
Horizontal Installation of TLP Tendons
Authors: Li Guang (George) , Kipp Robert , Leverette Steve
Published: August 2013

Tension Leg Platforms (TLPs) are ideal supports for dry-tree top tension riser systems because their tendons exhibit high tensile stiffness and significantly reduce the heave, pitch, and roll motions of the platforms. Since the first TLP (Hutton) was installed in the North Sea in 1984, a total of 24 TLPs have been installed throughout the world with 16 of them installed in the Gulf of Mexico. Currently there are new TLP projects proposed in regions off the coast of Malaysia, West Africa, Brazil and Western Australia. Heavy-lift vessels were used to install tendons for most of these TLP’s. Tendon joints were assembled vertically from bottom part to top part. Using a heavy-lift vessel introduces significant cost and schedule challenge to TLP projects, especially ones located in remote regions.

A horizontal tendon installation methodology is presented in this paper. This innovative approach involves horizontal assembly of TLP tendon segments on a construction barge. The partially assembled tendon is then incrementally pulled out through a stinger at the barge stern and secured with a hold back clamp so that the next tendon joint can be connected. The process repeats itself until the whole tendon is assembled and deployed. The tendon is then upended to a vertical configuration and connected to a TLP or a foundation pile. In this paper, we examine the alternative equipment and configuration options in the horizontal installation methodology. We outline rationales to select the appropriate options and measures to reduce project cost and risks.
Sloshing: From Theory to Offshore Operations
Authors: Clauss Günther F. , Sprenger Florian , Dudek Matthias , Testa Daniel
Published: August 2013

The current demand in liquefied natural gas (LNG) from remote marine locations drives the design of floating LNG (FLNG) liquefaction or regasification facilities, where LNG is transferred to shuttle carriers (LNGC). During the loading procedure, which takes about 18–24 hours for a standard sized LNGC, free fluid surfaces and varying filling levels occur inside the internal cargo tanks. This condition is critical since the seakeeping behavior of the LNGC — especially the roll motion — is strongly influenced and varying. In order to estimate and forecast the LNGC motions, numerical methods based on potential theory are the most efficient and appropriate method. The selected approach is validated by model tests at 30% water filling height inside four prismatic tanks. In-depth analyses, including force and moment measurements between tanks and hull, revealed a discrepancy between the analytical natural modes of a prismatic tank and the resonance frequencies for four prismatic tanks mounted to a LNGC hull. This effect is caused by the ratio of rigid to added mass of the system as well as the fact that the tanks are mounted to a standard hull shape featuring a longitudinal bow-stern asymmetry. In order to investigate this phenomenon systematically, surface elevations inside the tanks and natural modes for a symmetric cuboid hull are compared to results for a standard LNGC hull, both with the same main dimensions. The influence of the tank positions is also considered by comparing the original (longitudinally asymmetric) LNGC tank positions on the cuboid hull to an exactly symmetric arrangement.
Assessment of Container Mountings in Modular Offshore Platform Designs for Arctic Regions
Authors: Michel Josefine , Kaeding Patrick
Published: August 2013

Regularly the twistlock system is used to mount containers on container vessels or on offshore platforms as service containers in normal climate regions. In this paper the twistlock system is analyzed with respect to mounting auxiliary systems as well as accommodation and service modules to the deck of offshore platforms in arctic regions. When the twistlock systems are used in harsh environment it is also important that the twistlocks withstand the acting forces without great displacements and without exceeding the elastic range. But in arctic regions the mountings must resist additional forces due to ice interaction, cold temperatures and small friction coefficients. Because the existing rules do not include regulations how to analyze the strength of these mountings in arctic regions the influence of the friction coefficients and the Young’s modulus were of interest in this study. This paper summarizes some numerical works on these new discoveries. The results of the computations show that the Young’s modulus has no influence on the stress and the displacement of the bodies. However, the friction coefficient has influence on the stress specified in the simulations for large roll angles.
Airgap Statistics for a Tension Leg Platform
Authors: Gaidai Oleg , Naess Arvid , Stansberg Carl Trygve
Published: August 2013

The paper discusses a method for estimating extreme value statistics of the airgap for floating offshore platforms subjected to random events. Extensive model tests were performed in a large wave basin for a TLP (Tension Leg Platform) operating in the Norwegian Sea. Among several critical parameters, the airgap was measured at a number of locations under the platform deck. The wave in deck impact is a critical safety issue with respect to the deck damage and occurrence of extreme tether tensions. The authors have utilized experimental data to look at critical airgaps under the deck in random waves. Conclusions are drawn about extreme airgap statistics, and consequently about the wave impact probability in severe seas. This paper can be seen as continuing the efforts in the challenging study of the airgap issue, [2, 6–10].
State-of-the-Art: Fatigue Life Extension of Offshore Installations
Authors: Martinez Luis Lopez , Barsoum Zuheir , Paradowska Anna
Published: August 2013

The use of fatigue life improvement techniques and specifically ultrasonic peening treatment to extend the service life of offshore structures has become an accepted practice during the last five years. The understanding of the process as well as equipment’s upgrading for treatment in-situ including quality control and assurance have been developed up to a level that it has become a current practice in many parts of the world.

However, the efficiency of the ultrasonic peening is strictly dependent on the deep understanding of significant fatigue parameters as weld defects, stress concentrations and residual stresses and their interaction. In this paper we attempt to present the current knowledge and the physical reasons why the ultrasonic peening treatment is able to improve the fatigue life of welded joints.

The local weld geometry or stress concentration, weld imperfections as well as welding residual stresses are all modified and improved by the application of ultrasonic peening.

Local weld geometry and weld process inherent weld imperfections are the factors primarily influencing the fatigue strength in welded joints. Comprehensive studies have been carried out during the last 20 years in order to detect and document the weld defects as well as to understand their origin and effect on the fatigue strength of welds. Analogous efforts have been dedicated to understand and document the influence of local weld geometries on the stress concentrations and its influence on endurance and structural integrity.

Similarly, efforts have been done to understand the influence of the relaxation by external loads of the by the ultrasonic peening treatment induced compressive stresses.

Fatigue test results of ultrasonic peening treated relevant weld details have been used to assess the potential life extension. The results showed four to six times fatigue life extension. The spectrum fatigue test was designed to confirm that relaxation by service loads of the induced compressive stresses during ultrasonic peening treatment would not diminish the benefit.
How Does Barge-Master Compensate for the Barge Motions: Experimental and Numerical Study
Authors: Jaouen Frederick , van den Berg Joris , van der Schaaf Haite , May Eelko , Koppenol Jim
Published: August 2013

To increase workability and safety in tough environmental conditions, and to create a more economical alternative for jack-up barges, Barge-Master has developed a wave compensating platform for marine and offshore installation barges. To minimize the motions of the crane positioned on top of it, the platform is driven by three hydraulic actuators that compensate for the roll, pitch and heave motions of the barge. To quantify the performance of the platform for different environmental conditions and crane configurations MARIN performed both wave basin model tests and time-domain simulations on the platform. In this paper, the experimental setup is first described and the model test results are presented. Then, the theoretical formulation of the time-domain aNySIM model is described and the numerical results are reported. It is shown that the model tests and time-domain results are in good agreement. The results indicate that the barge motions can be compensated by the platform for more than 90% in 1.2m high sea states. However, it is also shown that the instrumentation, data acquisition and controller system need to be fast and tuned to achieve this optimal compensation.
Beachpull Installation of Long Pipelines and Cables
Authors: Bhargav Kiran , Durairaj Senthilkumar
Published: August 2013

Conventional pipelay (i.e. S-lay) is not feasible in shallow water locations owing to the draft of pipelay barges. Pipelay using beachpull method provides an alternative to such restrictions. A typical long beachpull operation in shallow water environment presents a substantial challenge, which calls for a thorough engineering analysis along with a detailed installation procedure.

This paper highlights the methods and techniques of pipelay using beachpull method that were employed on the John Brookes joint venture (Apache and Santos) and the Aramco Karan project. The John Brookes project (Varanus Island, Australia) included the installation of a landfall section comprising an 18” FBE coated pipeline featuring a beachpull length of 7.0 km, one of the longest of its kind. The Karan project (Saudi Arabia) comprised the installation of a 38” trunkline, requiring a beachpull length of 3.0 km and also the installation of a 15kV cable having a beachpull length of 4.0 km.

Beachpull engineering comprised checking the pipeline’s lateral stability under the influence of near-shore current-induced hydrodynamic forces. For the Apache Project, the 7.0 km long beachpull coupled with the proximity to the existing pipeline and near-shore currents offered a unique challenge. Supplementary buoyancy was utilized to limit the required beachpull tension within allowable limits. The drifting of the pipeline from the installation corridor was restricted by installing sand-filled bulker bags at designed intervals. The beachpull installation on the Karan project offered a different challenge owing to a larger pipe size and a piggybacked cable in a shallow water depth. Special consideration was given to the attachment of supplementary buoyancy bags and dynamic loadings that were acting throughout the beachpull length, especially during cable installation.

This paper describes the technical challenges faced during the estimation of the pull-in loads and weather-induced lateral displacements encountered during the beachpull. This paper also elaborates the assessment of proposed winch, design of supplementary buoyancy, design of bulker bags, etc.

Data collected on-site during installation of the pipelines are in good agreement with computed / designed values, ensuring the correctness of the beachpull simulations. Detailed engineering studies along with well developed installation procedures resulted in successful completion of the installation.
Extend Reel-Ability of HMC New Aegir Reeling Vessel Based on Reliability Based Assessment and Bending Tests Program
Authors: Karjadi Erwan , Smienk Henk , Boyd Helen , Aamlid Olav
Published: August 2013

Heerema Marine Contractors (HMC) is entering a new era of pipe laying using the reel-lay method for deep and shallow water pipeline installation projects. The new Deep water Construction Vessel (DCV) Aegir is designed to be able to reel/J-lay pipelines for a range of pipe dimension and water depth combinations which on the one side is governed by the equipment limitations (reel drum size, top tension capacity) and on the other side is limited by the code (DNV, API) acceptance criteria for reel/J-lay installation. The paper describes how the code standard acceptance criteria, which have been used to estimate the reel-ability of DCV Aegir and are generally known as conservative approach, can be relaxed in a reliable manner in order to safely extend the DCV Aegir reeling capability. This approach will permit a reduction of minimum reelable pipe wall thickness and result in a wider envelope of water depth applications for reeling from the DCV Aegir. The methodology of relaxation for local buckling and residual ovality criteria has been developed with and approved by DNV specifically for the spooling-on with the DCV Aegir configuration. A series of bend rig tests have been performed at Heriot-Watt University to confirm and validate the new proposed minimum reelable pipe wall thickness. In line with the development of the extended reeling capability, the required tighter specifications for seamless pipe purchased for reeling has been discussed.
Study of Vibration Instability of TTR With Varying Axial Force and Tension Ring
Authors: Tang You-gang , Shao Wei-dong
Published: August 2013

The parametric-excitation vibration characteristics are investigated considering the tension-ring’s effect and mode coupling of riser. The Floquet theory is used to study the parametric stability of deep-water risers as the top boundary condition is pinned or moving with or without damping. The effect of frequency and the amplitude of heave motion on the riser vibration response are studied considering the effect of mode coupling.
Determination of Friction Within a Riser Umbilical
Authors: Olsen Elise , Karlsen Stian , Jordal Lars , Hansen-Zahl Kay A.
Published: August 2013

By combination of elements like hydraulic tubes, electrical and optical signal cables and electrical power cables, umbilicals provide remote control of subsea oil and gas wells. Riser umbilical’s are terminated at offshore platforms or vessels, and will be exposed to tension and bending variations caused by waves and vessel motions.

Understanding how forces are transmitted between the elements in an umbilical is vital for correct calculation of the umbilical design life. When umbilicals are exposed to tension and bending, tension will be imposed in the individual elements. The magnitude of tension is governed by the overall tension and bending and also by the lay angles, placement in the cross section and the friction forces between the elements.

Some friction coefficients may be found in literature, but not all material combinations, and not for the conditions inside an umbilical.

A project was therefore initiated with the aim of developing a friction testing device capable of determining friction coefficients between all elements in environments that are representative for the conditions within an umbilical, i.e.: at various temperatures; in sinusoidal movements, like the bending movements in an umbilical; at representative contact pressures, speeds and temperatures; in various environments, like air and seawater; without crumpling soft elements like synthetic tapes.
Environmental Impact Assessment for Offshore Pipelines
Authors: Bai Yong , Zukifli Zatil Akmal
Published: August 2013

The Environmental Impact Assessment (EIA) emphasize and intended to access and evaluate the impacts on the environment of any possible alternative and initiative in decision making process. In this paper, the biggest impact of oil spills in the history, which is the BP oil spill are discuss. The calculation especially calculate the oil spread by the average of wind and wave. The spread are effected while an oil spill in the water surface and expose to the environment. This exposure might evaporated to the air or maybe spread into the water flow and might be dissolved in the water it self. In making these calculation successfull, the main equation disscuss here are the dispersion model. This model cover all aspects of dispersion and its consequences while it is burst once at the atmosphere. Besides, in order to find the oil evaporation and its spreadable, the calculation have been made which is the same equation to calculate the SHELL spills before.