Design Drivers of Hybrid Riser Towers

2005 ◽  
Author(s):  
Franc¸ois Thie´baud ◽  
Ste´phane Luteyn ◽  
Dominique Pe´rinet
Keyword(s):  
Gulf Of Mexico ◽  
Cross Section ◽  
Loop Current ◽  
Distant Future ◽  
Flexible Pipes ◽  
Steel Catenary Risers ◽  
Key Drivers ◽  
Northern North Sea ◽  
Flexible Jumper ◽  
The Impact

DORIS Engineering and Stolt Offshore have jointly designed the three Girassol hybrid riser towers installed offshore Angola. They were the first riser towers designed to provide very efficient insulation properties in very deepwater conditions. Some towers are under development or construction for other fields but in similar design conditions. Based on the experience of Girassol, DORIS engineering and Stolt Offshore have developed the concept to adapt to much deeper waters (around 2500 m) and more severe environments such as the Gulf of Mexico loop current or hurricane waves. This paper will present the key drivers for design of riser towers in these environments addressing for example the impact on the bundle cross section, buoyancy requirements, top tank size, flexible jumper lengths. Limitations will be defined and explained both in terms of design, fabrication and installation. As FPSO units are likely to be part of the development of the Gulf of Mexico deepwater areas in the not-so-distant future, the benefit of riser towers will become obvious, given the existing facilities for fabrication along the coast and spreads for installation. Other areas such as the Mediterranean sea, or even the Northern North Sea are potential candidates for this type of riser arrangement which provides multiple benefits over steel catenary risers and flexible pipes.

scholarly journals Hurricane Katrina (2005). Part I: Complex Life Cycle of an Intense Tropical Cyclone

2007 ◽  
Vol 135 (12) ◽  
pp. 3905-3926 ◽  
Author(s):  
Ron McTaggart-Cowan ◽  
Lance F. Bosart ◽  
John R. Gyakum ◽  
Eyad H. Atallah
Keyword(s):  
Life Cycle ◽  
Gulf Of Mexico ◽  
Hurricane Katrina ◽  
Gulf Coast ◽  
The United States ◽  
Historical Record ◽  
Complex Life Cycle ◽  
Loop Current ◽  
The Bahamas ◽  
The Impact

Abstract The devastating effects of Hurricane Katrina (2005) on the Gulf Coast of the United States are without compare for natural disasters in recent times in North America. With over 1800 dead and insured losses near $40 billion (U.S. dollars), Katrina ranks as the costliest and one of the deadliest Atlantic hurricanes in history. This study documents the complex life cycle of Katrina, a storm that was initiated by a tropical transition event in the Bahamas. Katrina intensified to a category-1 hurricane shortly before striking Miami, Florida; however, little weakening was observed as the system crossed the Florida peninsula. An analog climatology is used to show that this behavior is consistent with the historical record for storms crossing the southern extremity of the peninsula. Over the warm Gulf of Mexico waters, Katrina underwent two periods of rapid intensification associated with a warm core ring shed by the Loop Current. Between these spinup stages, the storm doubled in size, leading to a monotonic increase in power dissipation until Katrina reached a superintense state on 28 September. A pair of extremely destructive landfalls in Louisiana followed the weakening of the system over shelf waters. Despite its strength as a hurricane, Katrina did not reintensify following extratropical transition. The evolution of the storm’s outflow anticyclone, however, led to a perturbation of the midlatitude flow that is shown in a companion study to influence the Northern Hemisphere over a period of 2 weeks. An understanding of the varied components of Katrina’s complex evolution is necessary for further developing analysis and forecasting techniques as they apply to storms that form near the North American continent and rapidly intensify over the Gulf of Mexico. Given the observed overall increase in Atlantic hurricane activity since the mid-1990s, an enhanced appreciation for the forcings involved in such events could help to mitigate the impact of similar severe hurricanes in the future.

Design Challenges for the K2 North Project Steel Catenary Risers

2005 ◽  
Author(s):  
Basim B. Mekha ◽  
Jie Fang ◽  
Mike Lemker
Keyword(s):  
Gulf Of Mexico ◽  
Early Stage ◽  
Third Party ◽  
Coating System ◽  
Insulation Coating ◽  
Steel Catenary Risers ◽  
Viv Suppression ◽  
Key Aspects ◽  
The Impact ◽  
Selection Of

The K2 North project located in Green Canyon Block 518 (GC518) in the Gulf of Mexico ties-back four subsea oil wells to a host facility (Marco Polo TLP) in the GC 608, in approximately 4300 feet water depth. The plan is to tie-back the subsea wells via dual pipe in pipe insulated flowlines through an insulated production manifold. Each well will connect to the manifold via insulated flowlines or insulated flowline jumpers. The flowlines connect to the host facility via Steel Catenary Risers (SCRs). These SCRs consist of heavy wall 6.625-inch pipe with wet buoyant insulation necessary to minimize the impact of top tension loads on the host facility. This paper discusses the key aspects of the design of the SCRs, and highlights the importance of a prudent engineering approach to deliver the optimal riser solution. These include the early identification of the potential for interference between the two project risers, and with the third party risers and adjacent TLP tendon. This design aspect was exacerbated by the weight limit imposed on the tieback risers, and by the use of VIV suppression strakes suitable for the selected installation method. The paper describes the solutions developed to avoid interference relating to riser layout and configurations and selection of wet insulation coating system. The paper also presents the qualification tests planned and conducted to prove the suitability of the wet insulation coating system for the S-lay installation method. K2 North (GC518) risers will be the first application of this coating on SCRs. The paper also demonstrates the importance of allowing sufficient margin in early stage of design to accommodate future changes as design matures, especially for fast track projects like this one. The K2 North SCRs represent typical subsea tieback scenarios in the Gulf of Mexico. The experience gained during the engineering design of these risers is therefore of significant value with regard to assisting in safe and economic design of such future developments.

scholarly journals Oxidative Stress in the Tumor Microenvironment and Its Relevance to Cancer Immunotherapy

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 986
Author(s):  
Nada S. Aboelella ◽  
Caitlin Brandle ◽  
Timothy Kim ◽  
Zhi-Chun Ding ◽  
Gang Zhou
Keyword(s):  
Oxidative Stress ◽  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Redox Homeostasis ◽  
Tumor Rejection ◽  
Oxygen Species ◽  
Antitumor Effects ◽  
Key Drivers ◽  
Cancer Immunotherapies ◽  
The Impact

It has been well-established that cancer cells are under constant oxidative stress, as reflected by elevated basal level of reactive oxygen species (ROS), due to increased metabolism driven by aberrant cell growth. Cancer cells can adapt to maintain redox homeostasis through a variety of mechanisms. The prevalent perception about ROS is that they are one of the key drivers promoting tumor initiation, progression, metastasis, and drug resistance. Based on this notion, numerous antioxidants that aim to mitigate tumor oxidative stress have been tested for cancer prevention or treatment, although the effectiveness of this strategy has yet to be established. In recent years, it has been increasingly appreciated that ROS have a complex, multifaceted role in the tumor microenvironment (TME), and that tumor redox can be targeted to amplify oxidative stress inside the tumor to cause tumor destruction. Accumulating evidence indicates that cancer immunotherapies can alter tumor redox to intensify tumor oxidative stress, resulting in ROS-dependent tumor rejection. Herein we review the recent progresses regarding the impact of ROS on cancer cells and various immune cells in the TME, and discuss the emerging ROS-modulating strategies that can be used in combination with cancer immunotherapies to achieve enhanced antitumor effects.

scholarly journals Charged current Drell-Yan production at N3LO

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Claude Duhr ◽  
Falko Dulat ◽  
Bernhard Mistlberger
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross Section ◽  
Production Cross ◽  
Hadron Collider ◽  
Charge Asymmetry ◽  
Charged Current ◽  
Leading Order ◽  
Neutrino Pair ◽  
The Impact

Abstract We present the production cross section for a lepton-neutrino pair at the Large Hadron Collider computed at next-to-next-to-next-to-leading order (N3LO) in QCD perturbation theory. We compute the partonic coefficient functions of a virtual W± boson at this order. We then use these analytic functions to study the progression of the perturbative series in different observables. In particular, we investigate the impact of the newly obtained corrections on the inclusive production cross section of W± bosons, as well as on the ratios of the production cross sections for W+, W− and/or a virtual photon. Finally, we present N3LO predictions for the charge asymmetry at the LHC.

scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cross Section ◽  
Negative Impact ◽  
Tensile Tests ◽  
Thermal Recovery ◽  
Bending Test ◽  
Small Scale ◽  
Spruce Wood ◽  
The Impact

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

The impact cross section of ErF3 centers in ZnS thin film

1988 ◽  
Vol 40-41 ◽  
pp. 786-787
Author(s):  
Baozhu Luo ◽  
Jiaqi Yu ◽  
Guozhu Zhong
Keyword(s):  
Thin Film ◽  
Cross Section ◽  
The Impact

The influence of Gulf of Mexico Loop Current intrusion on the transport of the Florida Current

2010 ◽  
Vol 60 (5) ◽  
pp. 1075-1084 ◽  
Author(s):  
Yuehua Lin ◽  
Richard J. Greatbatch ◽  
Jinyu Sheng
Keyword(s):  
Gulf Of Mexico ◽  
Florida Current ◽  
Loop Current

scholarly journals Decomposition Analysis of Void Reactivity Coefficient for Innovative and Modified BWR Assemblies

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Andrius Slavickas ◽  
Raimondas Pabarčius ◽  
Aurimas Tonkūnas ◽  
Gediminas Stankūnas
Keyword(s):  
Cross Section ◽  
Safety Concern ◽  
Functional Module ◽  
Decomposition Analysis ◽  
Fuel Burnup ◽  
Mox Fuel ◽  
High Enrichment ◽  
Reactivity Coefficient ◽  
The Impact ◽  
Irradiation Cycle

The decomposition analysis of void reactivity coefficient for innovative BWR assemblies is presented in this paper. The innovative assemblies were loaded with high enrichment UO2and MOX fuels. Additionally the impact of the moderation enhancement on the void reactivity coefficient through a full fuel burnup discharge interval was investigated for the innovative assembly with MOX fuel. For the numerical analysis the TRITON functional module of SCALE code with ENDF/B-VI cross section library was applied. The obtained results indicate the influence of the most important isotopes to the void reactivity behaviour over a fuel burnup interval of 70 GWd/t for both UO2and MOX fuels. From the neutronic safety concern positive void reactivity coefficient values are observed for MOX fuel at the beginning of the fuel irradiation cycle. For extra-moderated assembly designs, implementing 8 and 12 water holes, the neutron spectrum softening is achieved and consequently the lower void reactivity values. Variations in void reactivity coefficient values are explained by fulfilled decomposition analysis based on neutrons absorption reactions for separate isotopes.

Sign in / Sign up

Export Citation Format

Share Document