Closure to “Selection of Design Wave for Offshore Structures”

1959 ◽  
Vol 85 (3) ◽  
pp. 255-256
Author(s):  
Charles L. Bretschneider
Keyword(s):  
Offshore Structures ◽  
Selection Of

Selection of Design Lower Deck Elevation of Fixed Offshore Platforms for Mexican Code

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Dante Campos ◽  
César Ortega ◽  
Jorge L. Alamilla ◽  
Alberto Soriano
Keyword(s):  
Tropical Cyclones ◽  
Offshore Structures ◽  
Offshore Platforms ◽  
Mean Sea Level ◽  
Maintenance And Repair ◽  
Equipment Replacement ◽  
Expected Values ◽  
Definition Of ◽  
Selection Of ◽  
Lower Deck

This paper presents the definition of lower deck elevation (LDE) of fixed offshore platforms in Mexican part of the Gulf of Mexico (GoM), which were applied in the Mexican code for design and assessment of fixed offshore structures NRF-003-PEMEX-2007. This was obtained as a result of a decision methodology developed here, an optimization algorithm composed of an objective minimization function subject to a safety restriction and by the application of a set of real structural maintenance and equipment replacement costs. Platform projected service life dependent total costs of LDE contemplate expected costs of structural and equipment maintenance after the occurrence of tropical cyclones and northers, and the expected cost of equipment mobilization. This work regards a group of offshore platforms in the Bay of Campeche whose elevation lies between 15.85 and 19.10 m above mean sea level, as well as recent metocean hazard information. Similar expected values of total costs due to maintenance and repair were obtained, while safety constrains demand the LDE not to be less than +19.10 m.

Influence of hydrodynamic effects on iceberg collisions

1990 ◽  
Vol 17 (3) ◽  
pp. 329-337 ◽  
Author(s):  
Michael Isaacson ◽  
Kevin McTaggart
Keyword(s):  
Added Mass ◽  
Offshore Structures ◽  
Ocean Engineering ◽  
Iceberg Drift ◽  
Added Masses ◽  
Waves And Currents ◽  
Fixed Structure ◽  
Wave Induced ◽  
Hydrodynamic Effects ◽  
Selection Of

This paper examines various hydrodynamic effects which should be considered when analyzing iceberg collisions with a fixed structure. Iceberg added mass is among the hydrodynamic parameters that must be known to evaluate collision severity. Effective added mass is shown to vary with collision duration and recommendations are made for the selection of added masses to be used in iceberg collision design. Iceberg impact velocities are influenced by waves and currents, which can both be significantly influenced by the presence of a large structure. Wave-driven iceberg drift motions are shown to be more sensitive than current-driven motions to the presence of a structure. The contribution of wave-induced oscillatory motions to impact velocity is also discussed. Key words: added mass, hydrodynamics, ice impact, icebergs, ocean engineering, offshore structures.

Optimum selection of design parameters for transportation of offshore structures

2009 ◽  
Vol 36 (5) ◽  
pp. 330-338 ◽  
Author(s):  
J.L. Alamilla ◽  
D. Campos ◽  
C. Ortega ◽  
A. Soriano ◽  
J.L. Morales
Keyword(s):  
Offshore Structures ◽  
Design Parameters ◽  
Optimum Selection ◽  
Selection Of

scholarly journals Fatigue of Jacket Platforms: Effect of Marine Growth Modelling

2005 ◽  
Author(s):  
Franck Schoefs ◽  
Morgan Boukinda ◽  
Christophe Guillo ◽  
Antoine Rouhan
Keyword(s):  
Fatigue Behavior ◽  
Offshore Structures ◽  
Hydrodynamic Coefficients ◽  
Growth Modelling ◽  
Growth Effects ◽  
Growth Profile ◽  
Jacket Structures ◽  
Selection Of

After decades of developments of methods and software, reassessment of jacket structures is still a challenge. This paper focus on marine growth effects in case of fatigue behavior for Jacket offshore structures. Two main items are pointed out: selection of marine growth profile and modeling of hydrodynamic coefficients in presence of marine growth. A complete approach is provided and completed with both sensitivity and uncertainty studies.

Cognitive gadgets and cognitive priors

2019 ◽  
Vol 42 ◽  
Author(s):  
Gian Domenico Iannetti ◽  
Giorgio Vallortigara
Keyword(s):  
Cognitive Neuroscience ◽  
Selection Of

Abstract Some of the foundations of Heyes’ radical reasoning seem to be based on a fractional selection of available evidence. Using an ethological perspective, we argue against Heyes’ rapid dismissal of innate cognitive instincts. Heyes’ use of fMRI studies of literacy to claim that culture assembles pieces of mental technology seems an example of incorrect reverse inferences and overlap theories pervasive in cognitive neuroscience.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

Measurements of the Cape Astrometric Survey of the Southern Hemisphere

1978 ◽  
Vol 48 ◽  
pp. 515-521
Author(s):  
W. Nicholson
Keyword(s):  
Southern Hemisphere ◽  
Automatic Measuring ◽  
Measuring Machine ◽  
Final Selection ◽  
Selection Of

SummaryA routine has been developed for the processing of the 5820 plates of the survey. The plates are measured on the automatic measuring machine, GALAXY, and the measures are subsequently processed by computer, to edit and then refer them to the SAO catalogue. A start has been made on measuring the plates, but the final selection of stars to be made is still a matter for discussion.

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