Design of Large-Size Suction Embedded Plate Anchors for Permanent Mooring Systems in the Gulf of Mexico

2021 ◽  
Author(s):  
Jinbo Chen ◽  
Caspar N. Heyl ◽  
Jason A. Newlin ◽  
Metin Karayaka
Keyword(s):  
Gulf Of Mexico ◽  
Field Performance ◽  
Design Considerations ◽  
The Past ◽  
Large Size ◽  
Sustained Loading ◽  
Production Platform ◽  
Out Of Plane ◽  
Present Design ◽  
Plate Anchors

Abstract Suction embedded plate anchors (SEPLAs) are an economic solution for the mooring system of a floating production platform and have been deployed both in the Gulf of Mexico (GoM) and around the globe with excellent field performance records. The design of SEPLAs has gradually matured over the past two decades for conventional SEPLAs, but debates continue both in the industry and academia, e.g., on the function of the flap and the required keying. These design aspects become more critical for permanent mooring systems in the GoM where the anchors have to resist large mooring tensions from hurricanes, and balancing safety and economy is a challenge. Thus, the objective of this paper is to present design considerations for large-size SEPLAs for permanent mooring systems in the GoM. The design considerations in this paper include the embedment loss, the functions of the flap and keying, cyclic loading, sustained loading, keying disturbance, and out-of-plane loading. Recommendations are provided to advance the design of large-size SEPLAs, and more specific guidance is offered relative to the ambiguous requirements currently in the industry guidelines.

A summary of beach nourishment in China: The past decade of practices

Shore & Beach ◽  
2020 ◽  
pp. 65-73
Author(s):  
Gen Liu ◽  
Feng Cai ◽  
Hongshuai Qi ◽  
Jianhui Liu ◽  
Gang Lei ◽  
...  
Keyword(s):  
Beach Nourishment ◽  
Developed Countries ◽  
Ecological Design ◽  
Optimized Design ◽  
Limited Information ◽  
Personal Communications ◽  
Design Considerations ◽  
The Past ◽  
Technological Advances ◽  
Urban Beaches

Beach nourishment has been widely used for beach protection around the world. However, there is limited information about beach nourishment in China. This study offers an overview of beach nourishment practices, status and technological advances in China, based on the literature, reports, and personal communications. The results demonstrate that beach nourishment has been recognized as an effective and environmentally friendly measure to combat coastal erosion and has been increasingly adopted in China, especially in the past decade. The unique characteristics of coastal China resulted in a difference in beach nourishment between China and Western developed countries in terms of the types, objectives, and shapes of beach nourishment. For the types of nourishments in China, there were approximately the same number of restored beaches and newly constructed beaches. For fill sediment, homogeneous fill and heterogeneous fill comprised 51.1% and 48.9% of projects, respectively. The objective of beach nourishment was mainly to promote coastal tourism, and the shape of nourished beaches was dominated by headland bays. This study also indicated that China has achieved a number of technological advances in beach nourishment, including methods of beach nourishment on severely eroded coasts and muddy coasts, an optimized design of drain pipes involved in urban beaches, and ecological design considerations. From the past decade of practices, four aspects were proposed as considerations for future nourishment: sand sources, technique advances, ecological effects, and management of beach nourishments.

scholarly journals DESIGN, ANALYSIS AND FIELD TEST OF A DYNAMIC FLOATING BREAKWATER

1976 ◽  
Vol 1 (15) ◽  
pp. 159 ◽  
Author(s):  
D.J. Agerton ◽  
G.H. Savage ◽  
K.C. Stotz
Keyword(s):  
Solid Wall ◽  
Offshore Structures ◽  
The Past ◽  
The North ◽  
Production Platform ◽  
Floating Breakwater ◽  
The North Sea ◽  
Floating Breakwaters ◽  
Offshore Oil ◽  
Permanent Wave

Interest in floating breakwaters has been generated in recent years because the concept offers the potential of providing a less expensive alternative to traditional, solid wall type barriers for providing permanent wave protection to the thousands of new recreational boat harbors and marinas that have been built in the past 20 years. Also, they may be able to provide temporary, mobile wave protection during construction and installation of offshore facilities for oil transfer and production operations, defense facilities and other offshore structures in deeper water (depths exceeding 50 to 100 feet). The engineering director of one of the largest and most active offshore oil producing companies recently stated that they would be willing to pay up to $6 million for a mobile, floating breakwater that had the proven capability to significantly reduce risks due to wave action during offshore erection in the North Sea or elsewhere. Considering the investment in just one deep water oil production platform already exceeds $100,000,000, the worth of such a reusable, wave protection system during the critical erection period of a platform should be large.

Empires Versus States

2017 ◽  
Author(s):  
Josep M. Colomer
Keyword(s):  
United States ◽  
European Union ◽  
United States Of America ◽  
The European Union ◽  
The Past ◽  
Large Size ◽  
Analytical Category

The classical analytical category of “empire,” as opposed to “state,” “city,” “federation,” and other political forms, can account for a large number of historical and current experiences, including the past United States of America, the European Union, Russia, and China. An “empire” has been conceived, in contrast to a “state,” as a very large size polity with a government formed on movable frontiers, with multiple institutional levels, overlapping jurisdictions, and asymmetric relations between the center and the diverse territorial units.

scholarly journals How Dietary Factors Affect DNA Methylation: Lesson from Epidemiological Studies

Medicina ◽  
2020 ◽  
Vol 56 (8) ◽  
pp. 374 ◽  
Author(s):  
Andrea Maugeri ◽  
Martina Barchitta
Keyword(s):  
Dna Methylation ◽  
Epidemiological Studies ◽  
Dietary Factors ◽  
Negative Effects ◽  
Cross Sectional ◽  
The Past ◽  
Large Size ◽  
Future Challenges ◽  
Public Health Strategies ◽  
The Relationship

Over the past decades, DNA methylation has been proposed as a molecular mechanism underlying the positive or negative effects of diet on human health. Despite the number of studies on this topic is rapidly increasing, the relationship between dietary factors, changes in DNA methylation and health outcomes remains unclear. In this review, we summarize the literature from observational studies (cross-sectional, retrospective, or prospective) which examined the association of dietary factors (nutrients, foods, and dietary patterns) with DNA methylation markers among diseased or healthy people during the lifetime. Next, we discuss the methodological pitfalls by examining strengths and limitations of published studies. Finally, we close with a discussion on future challenges of this field of research, raising the need for large-size prospective studies evaluating the association between diet and DNA methylation in health and diseases for appropriate public health strategies.

scholarly journals XI.—On a Small Collection of Terrestrial Isopoda from Spain, with Descriptions of Four New Species.

1917 ◽  
Vol 51 (2) ◽  
pp. 461-465
Author(s):  
Walter E. Collinge
Keyword(s):  
New Species ◽  
Cambridge University ◽  
The Past ◽  
Large Size ◽  
Present Collection ◽  
Small Collection ◽  
University Museum

I am indebted to the kindness of Dr Leonard Doncaster, F.R.S., for the opportunity to examine the present collection of Terrestrial Isopoda from the Cambridge University Museum of Zoology.The Terrestrial Isopoda of Spain have received considerable attention in the past at the hands of L. Koch,* Budde-Lund,† O. De Buen,‡ and Dollfus,§ and present many features of great interest, one of the most striking of which is perhaps the large size of the various species, particularly in the genera Porcellio, Latreille, and Armadillidium, Brandt, and to these I am now able to add the genus Cubaris, Brandt.

The Effect of Mooring System and Sheared Currents on Vortex Induced Motions of Truss Spars

2003 ◽  
Author(s):  
Radboud R. T. van Dijk ◽  
Arjan Voogt ◽  
Paul Fourchy ◽  
Saadat Mirza
Keyword(s):  
Gulf Of Mexico ◽  
Mooring System ◽  
Test Results ◽  
Current Profile ◽  
Scaled Model ◽  
Production Platform ◽  
Helical Strakes ◽  
Truss Spar ◽  
Set Up ◽  
Program Show

Since 1996 Spars have been used as production platform in the Gulf of Mexico. Spar Vortex Induced Motions (VIM) in strong currents like the hurricane and loop currents are an important consideration for the design of the mooring system and risers. This is important for the extreme offsets as well as fatigue in risers and the mooring system. This paper compares the VIM behavior of a truss Spar in sheared currents, like the Hurricane current in the Gulf of Mexico, with tow test results. Experiments have been carried out on a scaled model in both a complete mooring system and in a towing set-up with a simplified horizontal mooring. The Spar model consists of a hard tank with removable helical strakes, a truss section and a square soft tank. The results of this model test program show that both the choice of the mooring system and current profile have a significant influence on the VIM response of the Spar. The paper discusses the results of this research and also addresses important issues and considerations for VIM model tests.

Influence of number of cycles on strain

1978 ◽  
Vol 15 (4) ◽  
pp. 584-592 ◽  
Author(s):  
Vijay K. Khosla ◽  
Ram D. Singh
Keyword(s):  
Stress Level ◽  
Permanent Deformation ◽  
Field Performance ◽  
Complete Spectrum ◽  
Ottawa Sand ◽  
The Past ◽  
Stress Cycles ◽  
Number Of Cycles ◽  
Made In

In the past, tests conducted on sand to evaluate the field performance of machine foundations have utilized only a limited number of load cycles. Results of these tests were extrapolated to determine the permanent deformation experienced by the foundation materials over the life of the machines. An attempt has been made in this presentation to develop a complete spectrum of the variation of strain with stress level and number of loading cycles for anisotropically consolidated Ottawa sand. Up to 10 million stress cycles were applied. The axial strains show three distinct stages of strain with number of cycles.

Potential invasion of the Gulf of Mexico by Protemblemaria punctata (Teleostei: Chaenopsidae), a cryptobenthic fish endemic to Venezuela

2020 ◽  
Author(s):  
Jimmy Argüelles-Jiménez ◽  
Merari Contreras-Juarez ◽  
Eduardo Palacio Pérez
Keyword(s):  
Invasive Species ◽  
Gulf Of Mexico ◽  
Small Body ◽  
The Past ◽  
Oil Platforms ◽  
Offshore Oil Platforms ◽  
Viable Population ◽  
Body Sizes ◽  
The Caribbean ◽  
Offshore Oil

The movement of species to areas outside their native ranges has greatly intensified over the past few decades. However, detecting invasive species often requires detailed and regular surveys, especially for animals with small body sizes. A cryptobenthic fish endemic to the Caribbean coast of Venezuela, Protemblemaria punctata (Cervigón, 1966), is reported here from the southwestern Gulf of Mexico, based on the collection of 8 specimens (5 males and 3 females) from Bajo Mersey, a coral reef in the Parque Nacional Sistema Arrecifal Veracruzano (PNSAV). The collected specimens were taken from sessile worm tubes that grew on PVC structures previously placed on the reef at a depth of 6 m. The number of P. punctata specimens we collected could indicate that the species has established a viable population on the reefs in the PNSAV. The colonization of P. punctata in the Gulf of Mexico waters may be due to the dispersal of individuals present on offshore oil platforms that are transported from Trinidad to Venezuela and the Gulf of Mexico.

The value of pi

1963 ◽  
Vol 10 (2) ◽  
pp. 100
Author(s):  
Ann Setzekorn
Keyword(s):  
Eighth Grade ◽  
Mathematics Textbooks ◽  
The Past ◽  
Large Size ◽  
Basketball Court

Most seventh- and eighth-grade mathematics textbooks suggest that the pupils measure the circumference and diameter of such objects as waste baskets, pie pans, and funnels; and that from these measurements they compute an approximate value for pi. For the past several years we have been using the large circles on the basketball court in our gymnasium. We find a decided advantage in the rather large size of the circles.

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