Peak Accelerations of Equipment Within a Bundle Towhead During Pile Driving Operations

2015 ◽  
Author(s):  
Graeme Roberts ◽  
T. Sriskandarajah ◽  
Umberto Arosio ◽  
Nick McDonald ◽  
Dirk Pingen ◽  
...  
Keyword(s):  
North Sea ◽  
Clay Soil ◽  
Design Solution ◽  
Pile Driving ◽  
Silty Clay ◽  
Space Frame ◽  
The North ◽  
The North Sea ◽  
And Control ◽  
Silty Clay Soil

Pipeline bundles are towed to site between towhead manifold structures which are designed to contain all the manifold valve-work and control equipment. The towhead is a space frame that not only supports and protects the on-board equipment during service but also allows the attachment of temporary buoyancy units that are necessary for the towing and controlled ballasting operations during installation. Pre-installed equipment within the towhead space-frame must be operable following the bundle on-shore transportation, launch, offshore tow and pile driving operations that are necessary to secure some towheads to the seabed. The analysis work reported in this paper focuses on pile driving activities and was carried out to demonstrate that forced acceleration of pre-installed equipment, caused by transmission of pile driving energy to the towhead, did not exceed the equipment’s recommended allowable shock limits. The desired outcome of the analyses was an understanding that equipment pre-installation offered an acceptable design solution for a particular towhead configuration founded on a soft silty clay soil in the North Sea and that this outcome would be applicable to future similar towheads.

Clay mineral distribution and provenance in Mesozoic and Tertiary mudrocks of the Moray Firth and northern North Sea

Clay Minerals ◽  
1990 ◽  
Vol 25 (4) ◽  
pp. 519-541 ◽  
Author(s):  
M. J. Pearson
Keyword(s):  
Clay Mineral ◽  
North Sea ◽  
Volcanic Activity ◽  
Volcanic Material ◽  
The North ◽  
Moray Firth ◽  
History Of ◽  
The North Sea ◽  
Northern North Sea ◽  
And Control

AbstractClay mineral abundances in Mesozoic and Tertiary argillaceous strata from 15 exploration wells in the Inner and Outer Moray Firth, Viking Graben and East Shetland Basins of the northern North Sea have been determined in <0·2 µm fractions of cuttings samples. The clay assemblages of more deeply-buried samples cannot be unambiguously related to sedimentary input because of the diagenetic overprint which may account for much of the chlorite and related interstratified minerals. Other sediments, discussed on a regional basis and related to the geological history of the basins, are interpreted in terms of clay mineral provenance and control by climate, tectonic and volcanic activity. The distribution of illite-smectite can often be related to volcanic activity both in the Forties area during the M. Jurassic, and on the NE Atlantic continental margin during the U. Cretaceous-Early Tertiary which affected the North Sea more widely and left a prominent record in the Viking Graben and East Shetland Basin. Kaolinite associated with lignite-bearing sediments in the Outer Moray Firth Basin was probably derived by alteration of volcanic material in lagoonal or deltaic environments. Some U. Jurassic and L. Cretaceous sediments of the Inner Moray Basin are rich in illite-smectite, the origin of which is not clear.

Transport and Water Quality Modelling in the Southern North Sea in Relation to Coastal Pollution Research and Control

1986 ◽  
Vol 18 (4-5) ◽  
pp. 245-256 ◽  
Author(s):  
J. A. van Pagee ◽  
H. Gerritsen ◽  
W P. M. de Ruijter
Keyword(s):  
Heavy Metals ◽  
Water Quality ◽  
Coastal Zone ◽  
North Sea ◽  
Water Levels ◽  
Coastal Pollution ◽  
The North ◽  
Pollution Research ◽  
The North Sea ◽  
And Control

Mathematical modelling techniques are used to quantify the transport in the southern part of the North Sea of pollutants originating from various inputs. Special attention was given to the anthropogenic increase in local concentrations of nutrients (N, P) and heavy metals (Cd, Hg, Cu, Pb, Zn, Cr) and their potential impact on marine organisms. A depth-averaged hydrodynamic model is used to calculate tidal and wind driven velocities and water levels. By averaging, residual flows are calculated, forming the basis for advective transports in a water quality model. Dispersive transports are derived from a comparison of simulated and observed salinity distributions. Water mass distributions and age functions for various inflowing water types are determined with the model. Transports of nutrients and heavy metals in the southern part of the North Sea are calculated using annual pollution inputs for 1980. Although interactions with bottom sediments are not considered, the calculated and measured concentrations show good similarities. The water quality in the Dutch coastal zone and German Bight area is shown to be highly determined by local pollution loads from the rivers Rhine, Weser and Elbe respectively. Comparison of simulated concentrations for 1980 with those resulting from simulations with estimated natural river inputs, shows that more than 50% of nutrients and heavy metal concentrations originate from human activities in large coastal zone areas. From toxicological information and standards, it is concluded that Cd, Hg and Cu are substances that need special attention in pollution research and control for the Dutch coastal waters.

scholarly journals Acute otitis externa in divers working in the North Sea: a microbiological survey of seven saturation dives

1977 ◽  
Vol 78 (3) ◽  
pp. 395-409 ◽  
Author(s):  
S. R. Alcock
Keyword(s):  
North Sea ◽  
Otitis Externa ◽  
Control Measures ◽  
Monitoring And Control ◽  
Ear Canal ◽  
The North ◽  
The North Sea ◽  
Offshore Oil Industry ◽  
And Control ◽  
Offshore Oil

SUMMARYSaturation diving is an important and widely used technique in the Offshore Oil Industry. During 1974–5 two saturation dives in the North Sea were terminated because of outbreaks of incapacitating otitis externa, and others were disrupted. Pseudomonas aeruginosa was consistently isolated from the ears of affected divers. Because complex work schedules were threatened seven subsequent dives were subjected to microbiological monitoring and control. Colonization of the ear canal with P. aeruginosa or with other gram-negative bacilli occurred in 39 (67%) of the 58 divers studied, usually within 7 days of starting the dive. Data obtained by serotyping the isolations of P. aeruginosa suggested that a single infected diver may be the source of organisms which rapidly spread to his colleagues and throughout the living chambers, that the living chambers may constitute a reservoir of infection during and between dives, and that certain serotypes of P. aeruginosa are more likely than others to colonize the ear canal in the conditions of a saturation dive. The control measures used during the dives were only partially effective, but none of the divers suffered severe pain and all the dives were an operational success.

Influence of Application Variables on Efficacy of Postemergence Applications of DPX-PE350

1993 ◽  
Vol 7 (3) ◽  
pp. 619-624 ◽  
Author(s):  
David L. Jordan ◽  
Robert E. Frans ◽  
Marilyn R. McClelland
Keyword(s):  
Nonionic Surfactant ◽  
Weed Control ◽  
Clay Soil ◽  
Silty Clay ◽  
Silt Loam ◽  
Silt Loam Soil ◽  
Loam Soil ◽  
Spray Volume ◽  
And Control ◽  
Silty Clay Soil

Experiments were conducted to compare control of entireleaf morningglory with POST applications of DPX-PE350 applied with no adjuvant, a nonionic surfactant, or crop oil concentrate in spray volumes of 94, 235, and 375 L ha−1. Control was greater with a nonionic surfactant or crop oil concentrate than with no adjuvant and control with crop oil concentrate exceeded control with the nonionic surfactant. Spray volume had no effect on efficacy. DPX-PE350 was more effective when applied to foliage only or to soil plus foliage than when applied to soil only after emergence of entireleaf morningglory. Control from soil-only applications was lower on a silty clay soil than on a silt loam soil. Except for sicklepod, mixing DPX-PE350 with fluometuron or MSMA had little effect on weed control.

The Miocene warmth from the North Sea Basin perspective

2021 ◽  
Author(s):  
Kasia K. Sliwinska ◽  
Jørgen Bojesen-Koefoed ◽  
Karen Dybkjær ◽  
Timothy Herbert ◽  
Caroline H. Lear ◽  
...  
Keyword(s):  
North Sea ◽  
Fine Sand ◽  
Coarse Fraction ◽  
Silty Clay ◽  
Sea Level Changes ◽  
Middle Latitudes ◽  
The North ◽  
The North Sea ◽  
Major Shift ◽  
High Concentrations

&lt;p&gt;The Miocene climate was dynamic, oscillating between major glaciation events and greenhouse conditions (the so-called Miocene Climatic Optimum or MCO). However, forcing factors responsible for climatic transitions from one state to another are not fully understood, partly because palaeoclimatological records from northern mid to high latitudes are scarce.&lt;/p&gt;&lt;p&gt;To better resolve climatic changes of the Miocene epoch in the northern middle latitudes we studied a unique, nearly complete sedimentary record (Sdr. Vium borehole) spanning the upper Aquitanian to the Tortonian of the North Sea Basin.&amp;#160;Newly obtained sea surface temperatures (SSTs) from our Miocene core revealed that the North Sea Basin was up to 20&amp;#176;C warmer than today, reaching the temperature maximum during the worldwide MCO (Herbert et al. 2020). Our high-resolution &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C, TOC and C/N records, as well as elemental detrital ratios (Si/Al, Zr/Rb, Zr/Al) derived from XRF reveal important changes in the source of organic matter and detrital coarse fraction of the sediment. During the Miocene the location of the Sdr. Vium borehole was situated in a proximal setting, with water depths varying between 0 and ~200 m, partly due to advancing and retreating delta lobes and partly due to relative sea level changes. We observe that the depositional environment had a large impact on our record. By far the most important of these changes is a condensed interval associated with phosphatization, pyritization, and glauconite, associated with a major shift from a dark brown, organic-rich, bioturbated silty clay with thin sand lenses (the Hodde Formation) towards a green and brown clay with high concentrations of green glaucony pellets of fine sand grade (the &amp;#216;rnh&amp;#248;j Formation). This shift is related to the subsidence of the North Sea Basin and marks the onset of a sediment-starvation in the basin.&lt;/p&gt;

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