Proceedings of the fifth international offshore mechanics and Arctic engineering (OMAE) symposium. Volume 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lunardini, V.J.; Wang, Y.S.; Ayorinde, O.A.

1986-01-01

This book presents the papers given at a symposium on offshore platforms. Topics considered at the symposium included climates, Arctic regions, hydrate formation, the buckling of heated oil pipelines in frozen ground, icebergs, concretes, air cushion vehicles, mobile offshore drilling units, tanker ships, ice-induced dynamic loads, adfreeze forces on offshore platforms, and multiyear ice floe collision with a massive offshore structure.

NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2013-10-01

NREL researchers are supporting offshore wind power development with computer models that allow detailed analyses of both fixed and floating offshore wind turbines. While existing computer-aided engineering (CAE) models can simulate the conditions and stresses that a land-based wind turbine experiences over its lifetime, offshore turbines require the additional considerations of variations in water depth, soil type, and wind and wave severity, which also necessitate the use of a variety of support-structure types. NREL's core wind CAE tool, FAST, models the additional effects of incident waves, sea currents, and the foundation dynamics of the support structures.

Review of technology for Arctic offshore oil and gas recovery. Appendices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sackinger, W. M.

1980-06-06

This volume contains appendices of the following: US Geological Survey Arctic operating orders, 1979; Det Noske Vertas', rules for the design, construction and inspection of offshore technology, 1977; Alaska Oil and Gas Association, industry research projects, March 1980; Arctic Petroleum Operator's Association, industry research projects, January 1980; selected additional Arctic offshore bibliography on sea ice, icebreakers, Arctic seafloor conditions, ice-structures, frost heave and structure icing.

Noble gas as tracers for CO2 deep input in petroleum reservoirs

NASA Astrophysics Data System (ADS)

Pujol, Magali; Stuart, Finlay; Gilfillan, Stuart; Montel, François; Masini, Emmanuel

2016-04-01

The sub-salt hydrocarbon reservoirs in the deep offshore part of the Atlantic Ocean passive margins are a new key target for frontier oil and gas exploration. Type I source rocks locally rich in TOC (Total Organic Carbon) combined with an important secondary connected porosity of carbonate reservoirs overlain by an impermeable salt layer gives rise to reservoirs with high petroleum potential. However, some target structures have been found to be mainly filled with CO2 rich fluids. δ13C of the CO2 is generally between -9 and -4 permil, compatible with a deep source (metamorphic or mantle). Understanding the origin of the CO2 and the relative timing of its input into reservoir layers in regard to the geodynamic context appears to be a key issue for CO2 risk evaluation. The inertness and ubiquity of noble gases in crustal fluids make them powerful tools to trace the origin and migration of mixed fluids (Ballentine and Burnard 2002). The isotopic signature of He, Ne and Ar and the elemental pattern (He to Xe) of reservoir fluid from pressurized bottom hole samples provide an insight into fluid source influences at each reservoir depth. Three main end-members can be mixed into reservoir fluids (e.g. Gilfillan et al., 2008): atmospheric signature due to aquifer recharge, radiogenic component from organic fluid ± metamorphic influence, and mantle input. Their relative fractionation provides insights into the nature of fluid transport (Burnard et al., 2012)and its relative migration timing. In the studied offshore passive margin reservoirs, from both sides of South Atlantic margin, a strong MORB-like magmatic CO2 influence is clear. Hence, CO2 charge must have occurred during or after lithospheric break-up. CO2 charge(s) history appears to be complex, and in some cases requires several inputs to generate the observed noble gas pattern. Combining the knowledge obtained from noble gas (origin, relative timing, number of charges) with organic geochemical and thermodynamic understanding of the fluid, in regards with the geodynamical context, helps us to unravel the complex fluid history of these deep environments. Ballentine C.J. and Burnard P.G. (2002). Rev. Mineral. Geochem., vol. 47, pp 481-538. Burnard P et al. (2012) EPSL 341, pp 68-78. Gilfillan, S.M.V. et al. (2008) GCA, vol. 72, pp 1174-1198.

The role of turbulent mixing in wind turbine wake recovery and wind array performance

NASA Astrophysics Data System (ADS)

Fruh, Wolf-Gerrit; Creech, Angus; Maguire, Eoghan

2014-05-01

The effect of wind turbine wakes in large offshore wind energy arrays can be a substantial factor in affecting the performance of turbines inside the array. Turbulent mixing plays a key role in the wake recovery, having a significant effect on the length over which the wake is strong enough to affect the performance other turbines significantly. We aim to highlight how turbulence affects wind turbine wakes, first by examining a high resolution CFD model of a single turbine wake validated by LIDAR measurements [1], and secondly with a much larger CFD simulation of Lillgrund offshore wind farm, validated with SCADA data [2]. By comparing the decay rates behind single turbines in environments of different surrounding surface features, ranging from ideal free-slip wind tunnels to mixed-vegetation hills, we suggest that the decay rate of turbine wakes are enhanced by free-stream turbulence, created by topography and ground features. In the context of Lillgrund wind farm, observations and computational results suggest that the wakes created by the turbines in the leading row facing the wind decay much slower than those in second row, or further into the turbine array. This observation can be explained by the diffusive action of upwind turbulence breaking up the wake generated by a turbine rotor. Angus CW Creech, Wolf-Gerrit Früh, Peter Clive (2012). Actuator volumes and hradaptive methods for threedimensional simulation of wind turbine wakes and performance. Wind Energy Vol.15, 847 - 863. Angus C.W. Creech, Wolf-Gerrit Früh, A. Eoghan Maguire (2013). High-resolution CFD modelling of Lillgrund Wind farm. Renewable Energies and Power Quality Journal, Vol. 11

Characterization of the dimensional stability of advanced metallic materials using an optical test bench structure

NASA Technical Reports Server (NTRS)

Hsieh, Cheng; O'Donnell, Timothy P.

1991-01-01

The dimensional stability of low-density high specific-strength metal-matrix composites (including 30 vol pct SiC(p)/SXA 24-T6 Al, 25 vol pct SiC(p)/6061-T6 Al, 40 vol pct graphite P100 fiber/6061 Al, 50 vol pct graphite P100 fiber/6061 Al, and 40 vol pct P100 graphite fiber/AZ91D Mg composites) and an Al-Li-Mg metal alloy was evaluated using a specially designed five-strut optical test bench structure. The structure had 30 thermocouple locations, one retroreflector, one linear interferometer multilayer insulation, and various strip heaters. It was placed in a 10 exp -7 torr capability vacuum chamber with a laser head positioned at a window port, and a laser interferometer system for collecting dimensional change data. It was found that composite materials have greater 40-C temporal dimensional stability than the AL-Li-Mg alloy. Aluminum-based composites demonstrated better 40-C temporal stability than Mg-based composites.

Risks to offshore installations in Europe due to natural hazards

NASA Astrophysics Data System (ADS)

Necci, Amos; Krausmann, Elisabeth

2017-04-01

Natural hazards, such as storms, earthquakes, or lightning are a major threat to industry. In particular, chemical plants, storage facilities, pipelines, and offshore oil and gas facilities are vulnerable to natural events which can cause hazardous materials releases and thereby endanger workers, the population and the environment. These technological accidents are commonly referred to as Natech accidents. Recent events have increased concerns about safety in the offshore oil and gas sector, and the need for improving knowledge on the matter has become evident. With those premises, we analyzed accidents, near misses and accident precursors at offshore facilities in Europe caused by natural events using both a statistical and a qualitative approach. For this purpose, we screened the World Offshore Accident Database (WOAD) to identify all incidents that featured natural events as causes or aggravating factors. A dataset of 1,085 global Natech events was built for the statistical analysis. Among those, a subset composed of 303 European records was selected. The results of the analysis showed that offshore Natech events in Europe are frequent; they resulted, however, in low consequences. The main threat to offshore facilities resulted from bad weather, such as strong winds and heavy seas. Storms can put intense loads on the structural parts of offshore installations, eventually exceeding design resistance specifications. Several incidents triggered by lightning strikes and earthquakes were also recorded. Substantial differences in terms of vulnerability, damage modality and consequences emerged between fixed and floating offshore structures. The main damage mode for floating structures was the failure of station keeping systems due to the rupture of mooring or anchors, mainly caused by adverse meteorological conditions. Most of the incidents at fixed offshore structures in Europe involved falling loads for both metal jacket and concrete base platforms due to storms. In contrast, in other parts of the world, and in particular in the Gulf of Mexico, tropical storms are likely to trigger severe direct damage to structures, resulting in platform capsizing, sinking or grounding. The in-depth analysis of the incident records also showed that the natural event was often just the triggering cause of the accident, which was frequently accompanied by contributing factors (e.g. corrosion, fatigue, wrong procedures, etc.). Under these circumstances, not only extreme storms, but also storms with moderate intensity can trigger incidents. Due to the high density of offshore structures and the unique environmental conditions promoting fatigue and corrosion, the North Sea is the area with the highest number of incidents recorded in Europe, as well as the area with the highest number of incidents at semi-submersible units in the world. About 4% of all reported global Natech events at offshore infrastructures involved casualties, and 2.6% for the European incident subset. Hazardous materials releases were documented for 21 events in Europe, resulting in fires and hydrocarbon spills polluting the sea. Furthermore, a surprisingly high number of severe events occurred during towing which highlights the impact of natural hazards on the safety of offshore transfer operations.

Study of self-ion irradiated nanostructured ferritic alloy (NFA) and silicon carbide-nanostructured ferritic alloy (SiC-NFA) cladding materials

NASA Astrophysics Data System (ADS)

Ning, Kaijie; Bai, Xianming; Lu, Kathy

2018-07-01

Silicon carbide-nanostructured ferritic alloy (SiC-NFA) materials are expected to have the beneficial properties of each component for advanced nuclear claddings. Fabrication of pure NFA (0 vol% SiC-100 vol% NFA) and SiC-NFAs (2.5 vol% SiC-97.5 vol% NFA, 5 vol% SiC-95 vol% NFA) has been reported in our previous work. This paper is focused on the study of radiation damage in these materials under 5 MeV Fe++ ion irradiation with a dose up to ∼264 dpa. It is found that the material surfaces are damaged to high roughness with irregularly shaped ripples, which can be explained by the Bradley-Harper (B-H) model. The NFA matrix shows ion irradiation induced defect clusters and small dislocation loops, while the crystalline structure is maintained. Reaction products of Fe3Si and Cr23C6 are identified in the SiC-NFA materials, with the former having a partially crystalline structure but the latter having a fully amorphous structure upon irradiation. The different radiation damage behaviors of NFA, Fe3Si, and Cr23C6 are explained using the defect reaction rate theory.

Investigation of the Hosgri Fault, offshore Southern California, Point Sal to Point Conception

USGS Publications Warehouse

Payne, C.M.; Swanson, O.E.; Schell, B.A.

1979-01-01

A high-resolution seismic reflection survey of the inner continental shelf between Point Sal and Point Conception has revealed faults that displace post-Wisconsin strata (less than 17,000-20,000 years). These faults are the Hosgri fault, the Offshore Lompoc fault, and smaller unnamed faults. Faults trending offshore from the adjacent shoreline such as the Pezzoni, Lions Head, Honda, and Pacifico faults, do not show post-Wisconsin activity. The Hosgri fault trends directly toward the coastline between Purisima Point and Point Arguello where it appears to merge with folds and smaller faults in the western Transverse Ranges. This trend of offshore structures toward the Point Arguello-Point Conception area is consistent with a hypothesis that the regional structural fabric of the southern California Coast Ranges and its adjacent offshore area merge with the Transverse Ranges.

Towers for Offshore Wind Turbines

NASA Astrophysics Data System (ADS)

Kurian, V. J.; Narayanan, S. P.; Ganapathy, C.

2010-06-01

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy from wind over the oceans and convert to electric energy. The advantages of offshore wind turbines as compared to land are that offshore winds flow at higher speed than onshore winds and the more available space. In some land based settings, for better efficiency, turbines are separated as much as 10 rotor diameters from each other. In offshore applications where only two wind directions are likely to predominate, the distances between the turbines arranged in a line can be shortened to as little as two or four rotor diameters. Today, more than a dozen offshore European wind facilities with turbine ratings of 450 kw to 3.6 MW exist offshore in very shallow waters of 5 to 12 m. Compared to onshore wind turbines, offshore wind turbines are bigger and the tower height in offshore are in the range of 60 to 80 m. The water depths in oceans where offshore turbines can be located are within 30 m. However as the distance from land increases, the costs of building and maintaining the turbines and transmitting the power back to shore also increase sharply. The objective of this paper is to review the parameters of design for the maximum efficiency of offshore wind turbines and to develop types offshore towers to support the wind turbines. The methodology of design of offshore towers to support the wind turbine would be given and the environmental loads for the design of the towers would be calculated for specific cases. The marine corrosion on the towers and the methods to control the corrosion also would be briefly presented. As the wind speeds tend to increase with distance from the shore, turbines build father offshore will be able to capture more wind energy. Currently two types of towers are considered. Cylindrical tubular structures and truss type structures. But truss type structures have less weight and flexibility in design. The construction of the offshore towers to harness the wind energy is also presented. The results will include the calculation of wind and wave forces on the tower and the design details for the tower.

40 CFR 125.138 - As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

Code of Federal Regulations, 2013 CFR

2013-07-01

... offshore oil and gas extraction facility, must I keep records and report? 125.138 Section 125.138... Intake Structures for New Offshore Oil and Gas Extraction Facilities Under Section 316(b) of the Act § 125.138 As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

40 CFR 125.138 - As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

Code of Federal Regulations, 2014 CFR

2014-07-01

... offshore oil and gas extraction facility, must I keep records and report? 125.138 Section 125.138... Intake Structures for New Offshore Oil and Gas Extraction Facilities Under Section 316(b) of the Act § 125.138 As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

40 CFR 125.138 - As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

Code of Federal Regulations, 2010 CFR

2010-07-01

... offshore oil and gas extraction facility, must I keep records and report? 125.138 Section 125.138... Intake Structures for New Offshore Oil and Gas Extraction Facilities Under Section 316(b) of the Act § 125.138 As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

40 CFR 125.138 - As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

Code of Federal Regulations, 2012 CFR

2012-07-01

... offshore oil and gas extraction facility, must I keep records and report? 125.138 Section 125.138... Intake Structures for New Offshore Oil and Gas Extraction Facilities Under Section 316(b) of the Act § 125.138 As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

40 CFR 125.138 - As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

Code of Federal Regulations, 2011 CFR

2011-07-01

... offshore oil and gas extraction facility, must I keep records and report? 125.138 Section 125.138... Intake Structures for New Offshore Oil and Gas Extraction Facilities Under Section 316(b) of the Act § 125.138 As an owner or operator of a new offshore oil and gas extraction facility, must I keep records...

Review and Recommendations for the Interagency Ship Structure Committee’s Fiscal 1984 Research Program,

DTIC Science & Technology

1983-01-01

Daily. Proposal Evaluation Procedure Organizations interested in doing the work adverstised submit proposals and cost estimates. The USCG contracting...types of offshore structures. These structures have largely been fixed platforms for petroleum drilling and production, and mobile offshore drilling...structures and of those mobile drilling units that are bottom supported, such as jack-ups and submersibles. Structures which are held in place by anchors

Proceedings of the Conference Arctic '85; Civil Engineering in the Artic offshore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, F.L.; Machemehl, J.L.

1985-01-01

Topics of the 1985 Conference included: Arctic construction, Arctic foundation, Arctic structures, and ocean effects. Arctic terminals and coastal offshore bases, protecting the Arctic environment, and probabilistic methods in Arctic offshore engineering were also discussed. Ice mechanics, marine pipelines in the Arctic, and the role of universities in training civil engineers for Arctic offshore development were highlighted. Sessions on remote sensing, surveying, and mapping were included, and offshore installations in the Bering Sea were discussed. Another topic of discussion was research in Civil Engineering for development of the Arctic offshore. The overall thrust of the conference was the application ofmore » Arctic offshore engineering principles and research in the field of oil and gas exploration and exploitation activity.« less

Seismic swarms and fluid flow offshore Central America

NASA Astrophysics Data System (ADS)

Dzierma, Yvonne; Thorwart, Martin; Hensen, Christian; Rabbel, Wolfgang; Wolf, Florian

2010-05-01

Offshore Nicaragua and Northern Costa Rica, the Cocos Plate subducts beneath the Caribbean Plate, carrying with it a large amount of fluids and volatiles. While some of these are set free at great depth beneath the volcanic arc, causing the extremely high water content observed in Nicaraguan mafic magmas (Carr et al., 2003; Kutterolf et al., 2007), some early dehydration reactions already release fluids from the subducting plate underneath the continental slope. Unlike in accretionary margins, where these fluids migrate up along the decollement towards the deformation front, fluid release at erosional margins seems to occur through fractures in the overriding plate (Ranero et al., 2008). Fluid seeps in this region have be observed at seafloor mounds, appearing as side-scan sonar backscatter anomalies or revealed by the presence of chemosynthetic communities (Sahling et al., 2008). In the framework of the General Research Area SFB 574 "Volatiles and Fluids in Subduction Zones", a network of 20 ocean-bottom-stations was deployed offshore Sta Elena Peninsula, Northern Costa Rica, from December 2005 to June 2006. Several distinct swarms of small earthquakes were observed at the seismic stations, which occurred clustered over a time period of several days and have very similar seismic waveforms. Since a correlation of fluid-release sites with the occurrence of sporadic seismic swarms would indicate that fluid migration and fracturing is the mechanism responsible for triggering the earthquake swarms, the events are re-analysed by double-difference localisation to enhance the resolution of the earthquake locations. The results are then considered to estimate the migration velocity and direction and compare the localisations with the known mound sites. Carr, M., Feigenson, M. D., Patino, L. C., and Walker, J. A., 2003: Volcanism and geochemistry in Central America: Progress and problems, in Eiler, J. (ed.), Inside the subduction factory, pp. 153-179, American Geophysical Union Kutterolf S., Freundt, A., Perez, W. Wehrmann, H., and Schmincke, H. U., 2007: Late Pleistocene to Holocene temporal succession and magnitudes of highly-explosive volcanic eruptions in west-central Nicaragua. J. Volc. Geothermal Res. 163, pp. 55-82 Ranero, C. R., Grevemeyer, I., Sahling, H., Barckhausen, U., Hensen, C., Wallmann, K., Weinrebe, W., Vannucchi, P., von Huene, R., and McIntosh, K., 2008: Hydrogeological system of erosional convergent margins and its influence on tectonics and interplate seismogenesis, Geochem. Geophys. Geosys., Vol 9, Nr 3 Sahling, H., Masson, D. G., Ranero, C. R., Hühnerbach, V., Weinrebe, W., Klauke, I., Bürk, D., Brückmann, W., and Suess, E., 2008: Fluid seepage at the continental margin offshore Costa Rica and southern Nicaragua, Geochem. Geophys. Geosys., Vol 9, Nr 5

78 FR 12037 - Announcement of the American Petroleum Institute's Standards Activities

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-21

... Execution, 1st Edition Standard 2CCU, Offshore Cargo Container Design, Manufacturing and Inspection, 1st... Integrity Management of Fixed Offshore Structures, 1st Edition Recommended Practice 2SM, Design, Manufacture... Offshore Production Platforms, 8th Edition Specification 14F, Design and Installation of Electrical Systems...

Aeroelastic Stability Investigations for Large-scale Vertical Axis Wind Turbines

NASA Astrophysics Data System (ADS)

Owens, B. C.; Griffith, D. T.

2014-06-01

The availability of offshore wind resources in coastal regions, along with a high concentration of load centers in these areas, makes offshore wind energy an attractive opportunity for clean renewable electricity production. High infrastructure costs such as the offshore support structure and operation and maintenance costs for offshore wind technology, however, are significant obstacles that need to be overcome to make offshore wind a more cost-effective option. A vertical-axis wind turbine (VAWT) rotor configuration offers a potential transformative technology solution that significantly lowers cost of energy for offshore wind due to its inherent advantages for the offshore market. However, several potential challenges exist for VAWTs and this paper addresses one of them with an initial investigation of dynamic aeroelastic stability for large-scale, multi-megawatt VAWTs. The aeroelastic formulation and solution method from the BLade Aeroelastic STability Tool (BLAST) for HAWT blades was employed to extend the analysis capability of a newly developed structural dynamics design tool for VAWTs. This investigation considers the effect of configuration geometry, material system choice, and number of blades on the aeroelastic stability of a VAWT, and provides an initial scoping for potential aeroelastic instabilities in large-scale VAWT designs.

SINGER: A Computer Code for General Analysis of Two-Dimensional Reinforced Concrete Structures. Volume 1. Solution Process

DTIC Science & Technology

1975-05-01

Conference on Earthquake Engineering, Santiago de Chile, 13-18 January 1969, Vol. I , Session B2, Chilean Association oil Seismology and Earth- quake...Nuclear Agency May 1975 DISTRIBUTED BY: KJ National Technical Information Service U. S. DEPARTMENT OF COMMERCE ^804J AFWL-TR-74-228, Vol. I ...CM o / i ’•fu.r ) V V AFWL-TR- 74-228 Vol. I SINGER: A COMPUTER CODE FOR GENERAL ANALYSIS OF TWO-DIMENSIONAL CONCRETE STRUCTURES Volum« I

Getting offshoring right.

PubMed

Aron, Ravi; Singh, Jitendra V

2005-12-01

The prospect of offshoring and outsourcing business processes has captured the imagination of CEOs everywhere. In the past five years, a rising number of companies in North America and Europe have experimented with this strategy, hoping to reduce costs and gain strategic advantage. But many businesses have had mixed results. According to several studies, half the organizations that have shifted processes offshore have failed to generate the expected financial benefits. What's more, many of them have faced employee resistance and consumer dissatisfaction. Clearly, companies have to rethink how they formulate their offshoring strategies. A three-part methodology can help. First, companies need to prioritize their processes, ranking each based on two criteria: the value it creates for customers and the degree to which the company can capture some of that value. Companies will want to keep their core (highest-priority) processes in-house and consider outsourcing their commodity (low-priority) processes; critical (moderate-priority) processes are up for debate and must be considered carefully. Second, businesses should analyze all the risks that accompany offshoring and look systematically at their critical and commodity processes in terms of operational risk (the risk that processes won't operate smoothly after being offshored) and structural risk (the risk that relationships with service providers may not work as expected). Finally, companies should determine possible locations for their offshore efforts, as well as the organizational forms--such as captive centers and joint ventures--that those efforts might take. They can do so by examining each process's operational and structural risks side by side. This article outlines the tools that will help companies choose the right processes to offshore. It also describes a new organizational structure called the extended organization, in which companies specify the quality of services they want and work alongside providers to get that quality.

[Offshore work and the work of nurses on board: an integrative review].

PubMed

Antoniolli, Silvana Aline Cordeiro; Emmel, Suzel Vaz; Ferreira, Gímerson Erick; Paz, Potiguara de Oliveira; Kaiser, Dagmar Elaine

2015-08-01

To know the production of theoretical approaches on issues related to offshore work and the work of offshore nurses. Integrative literature review conducted in the databases of LILACS, BDENF, MEDLINE, SciELO and Index PSI. We selected 33 studies published in national and international journals between 1997 and 2014. The thematic analysis corpus resulted in four central themes: offshore work environment; amid work adversities, an escape; structuring of offshore health and safety services; in search of safe practices. This study contributes to the offshore work of nurses in relation to the nature of work, acting amid adversities and the restless search for safe practices in the open sea.

Application of two passive strategies on the load mitigation of large offshore wind turbines

NASA Astrophysics Data System (ADS)

Shirzadeh, Rasoul; Kühn, Martin

2016-09-01

This study presents the numerical results of two passive strategies to reduce the support structure loads of a large offshore wind turbine. In the first approach, an omnidirectional tuned mass damper is designed and implemented in the tower top to alleviate the structural vibrations. In the second approach, a viscous fluid damper model which is diagonally attached to the tower at two points is developed. Aeroelastic simulations are performed for the offshore 10MW INNWIND.EU reference wind turbine mounted on a jacket structure. Lifetime damage equivalent loads are evaluated at the tower base and compared with those for the reference wind turbine. The results show that the integrated design can extend the lifetime of the support structure.

Different effects of propofol and isoflurane on cochlear blood flow and hearing function in Guinea pigs.

PubMed

Xiao, Ying; Wen, Jian; Bai, Yanxia; Duan, Na; Jing, G X

2014-01-01

To investigate the effects of isoflurane and propofol on mean arterial pressure (MAP), cochlear blood flow (CoBF), distortion-product otoacoustic emission (DPOAE), and the ultrastructure of outer hair cells (OHCs) in guinea pig cochleae. Forty-eight male guinea pigs were randomly assigned to one of six treatment groups. Groups 1 to 3 were infused (i.v.) with a loading dose of propofol (5 mg/kg) for 5 min and three maintenance doses (10, 20, or 40 mg kg-1·h-1, respectively) for 115 min. Groups 4 to 6 were inhaled with isoflurane at concentrations of 1.15 vol%, 2.30 vol% or 3.45 vol% respectively for 120 min. CoBF and MAP were recorded prior to and at 5 min intervals during drug administration. DPOAE was measured before, immediately after, and 1 h after administration. Following the final DPOAE test, cochleae were examined using scanning electron microscopy. Propofol treatment reduced MAP in a dose-dependent manner. CoBF and DPOAE showed increases at propofol maintenance doses of 10 and 20 mg kg-1·h-1. Inhalation of isoflurane at concentrations of 2.30 vol% and 3.45 vol% reduced MAP and CoBF. DPOAE amplitude increased following inhalation of 1.15 vol% isoflurane, but decreased following inhalations of 2.30 vol% and 3.45 vol%. Cochlear structure was changed following inhalation of either 2.30 vol% or 3.45 vol% isoflurane. Propofol could decrease MAP and increase both CoBF and DPOAE without affecting OHC structure. Inhalation of isoflurane at concentrations >2.30 vol% decreased CoBF and DPOAE, and produced injury to OHCs.

Long-term Bat Monitoring on Islands, Offshore Structures, and Coastal Sites in the Gulf of Maine, mid-Atlantic, and Great Lakes—Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Trevor; Pelletier, Steve; Giovanni, Matt

This report summarizes results of a long-term regional acoustic survey of bat activity at remote islands, offshore structures, and coastal sites in the Gulf of Maine, Great Lakes, and mid-Atlantic coast.

Review of technology for Arctic offshore oil and gas recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sackinger, W. M.

1980-08-01

The technical background briefing report is the first step in the preparation of a plan for engineering research oriented toward Arctic offshore oil and gas recovery. A five-year leasing schedule for the ice-prone waters of the Arctic offshore is presented, which also shows the projected dates of the lease sale for each area. The estimated peak production rates for these areas are given. There is considerable uncertainty for all these production estimates, since no exploratory drilling has yet taken place. A flow chart is presented which relates the special Arctic factors, such as ice and permafrost, to the normal petroleummore » production sequence. Some highlights from the chart and from the technical review are: (1) in many Arctic offshore locations the movement of sea ice causes major lateral forces on offshore structures, which are much greater than wave forces; (2) spray ice buildup on structures, ships and aircraft will be considerable, and must be prevented or accommodated with special designs; (3) the time available for summer exploratory drilling, and for deployment of permanent production structures, is limited by the return of the pack ice. This time may be extended by ice-breaking vessels in some cases; (4) during production, icebreaking workboats will service the offshore platforms in most areas throughout the year; (5) transportation of petroleum by icebreaking tankers from offshore tanker loading points is a highly probable situation, except in the Alaskan Beaufort; and (6) Arctic pipelines must contend with permafrost, making instrumentation necessary to detect subtle changes of the pipe before rupture occurs.« less

40 CFR 125.139 - As the Director, what must I do to comply with the requirements of this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil... the initial permit application from the owner or operator of a new offshore oil and gas extraction... offshore oil and gas extraction facility. In addition, the Director must review materials to determine...

40 CFR 125.139 - As the Director, what must I do to comply with the requirements of this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil... the initial permit application from the owner or operator of a new offshore oil and gas extraction... offshore oil and gas extraction facility. In addition, the Director must review materials to determine...

40 CFR 125.139 - As the Director, what must I do to comply with the requirements of this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil... the initial permit application from the owner or operator of a new offshore oil and gas extraction... offshore oil and gas extraction facility. In addition, the Director must review materials to determine...

40 CFR 125.139 - As the Director, what must I do to comply with the requirements of this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil... the initial permit application from the owner or operator of a new offshore oil and gas extraction... offshore oil and gas extraction facility. In addition, the Director must review materials to determine...

40 CFR 125.139 - As the Director, what must I do to comply with the requirements of this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil... the initial permit application from the owner or operator of a new offshore oil and gas extraction... offshore oil and gas extraction facility. In addition, the Director must review materials to determine...

NREL/University of Delaware Offshore Wind R&D Collaboration: Cooperative Research and Development Final Report, CRADA Number CRD-10-393

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musial, Walt

2015-11-12

Specifically, the work under this CRADA includes, but is not limited to, the development of test procedures for an offshore test site in Delaware waters; testing of installed offshore wind turbines; performance monitoring of those turbines; and a program of research and development on offshore wind turbine blades, components, coatings, foundations, installation and construction of bottom-fixed structures, environmental impacts, policies, and more generally on means to enhance the reliability, facilitate permitting, and reduce costs for offshore wind turbines. This work will be conducted both at NREL's National Wind Technology Center and participant facilities, as well as the established offshore windmore » test sites.« less

Residuals-Based Subgraph Detection with Cue Vertices

DTIC Science & Technology

2015-11-30

Workshop, 2012, pp. 129–132. [5] M. E. J. Newman , “Finding community structure in networks using the eigenvectors of matrices,” Phys. Rev. E, vol. 74, no...from Data, vol. 1, no. 1, 2007. [7] M. W. Mahoney , L. Orecchia, and N. K. Vishnoi, “A spectral algorithm for improving graph partitions,” CoRR, vol. abs

Sea Spray and Icing in the Emerging Open Water of the Arctic Ocean

DTIC Science & Technology

2015-06-12

concentrations of wind-generated sea spray and the resulting spray icing on offshore structures, such as wind turbines and exploration, drilling , and...We anticipate that structures placed in shallow water—wind turbines, drilling rigs, or man-made production islands, for instance—will, therefore...and the severity of sea spray icing on fixed offshore structures. We will use existing information on the relationship of the spray concentration

Design for perception management system on offshore reef based on integrated management

NASA Astrophysics Data System (ADS)

Peng, Li; Qiankun, Wang

2017-06-01

According to an analysis of actual monitoring demands using integrated management and information technology, a quad monitoring system is proposed to provide intelligent perception of offshore reefs, including indoor building environments, architectural structures, and facilities and perimeter integrity. This will strengthen the ability to analyse and evaluate offshore reef operation and health, promoting efficiency in decision making.

Study on optimized decision-making model of offshore wind power projects investment

NASA Astrophysics Data System (ADS)

Zhao, Tian; Yang, Shangdong; Gao, Guowei; Ma, Li

2018-02-01

China’s offshore wind energy is of great potential and plays an important role in promoting China’s energy structure adjustment. However, the current development of offshore wind power in China is inadequate, and is much less developed than that of onshore wind power. On the basis of considering all kinds of risks faced by offshore wind power development, an optimized model of offshore wind power investment decision is established in this paper by proposing the risk-benefit assessment method. To prove the practicability of this method in improving the selection of wind power projects, python programming is used to simulate the investment analysis of a large number of projects. Therefore, the paper is dedicated to provide decision-making support for the sound development of offshore wind power industry.

40 CFR 125.136 - As an owner or operator of a new offshore oil and gas extraction facility, what must I collect...

Code of Federal Regulations, 2011 CFR

2011-07-01

... stresses on the source waterbody. (B) Evaluation of potential cooling water intake structure effects. This... (CONTINUED) WATER PROGRAMS CRITERIA AND STANDARDS FOR THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil and Gas Extraction Facilities...

40 CFR 125.136 - As an owner or operator of a new offshore oil and gas extraction facility, what must I collect...

Code of Federal Regulations, 2010 CFR

2010-07-01

... stresses on the source waterbody. (B) Evaluation of potential cooling water intake structure effects. This... (CONTINUED) WATER PROGRAMS CRITERIA AND STANDARDS FOR THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil and Gas Extraction Facilities...

Offshore finfish aquaculture in the United States: An examination of federal laws that could be used to address environmental and occupational public health risks.

PubMed

Fry, Jillian P; Love, David C; Shukla, Arunima; Lee, Ryan M

2014-11-19

Half of the world's edible seafood comes from aquaculture, and the United States (US) government is working to develop an offshore finfish aquaculture industry in federal waters. To date, US aquaculture has largely been regulated at the state level, and creating an offshore aquaculture industry will require the development of a new regulatory structure. Some aquaculture practices involve hazardous working conditions and the use of veterinary drugs, agrochemicals, and questionable farming methods, which could raise environmental and occupational public health concerns if these methods are employed in the offshore finfish industry in the US. This policy analysis aims to inform public health professionals and other stakeholders in the policy debate regarding how offshore finfish aquaculture should be regulated in the US to protect human health; previous policy analyses on this topic have focused on environmental impacts. We identified 20 federal laws related to offshore finfish aquaculture, including 11 that are relevant to preventing, controlling, or monitoring potential public health risks. Given the novelty of the industry in the US, myriad relevant laws, and jurisdictional issues in an offshore setting, federal agencies need to work collaboratively and transparently to ensure that a comprehensive and functional regulatory structure is established that addresses the potential public health risks associated with this type of food production.

Offshore Finfish Aquaculture in the United States: An Examination of Federal Laws That Could be Used to Address Environmental and Occupational Public Health Risks

PubMed Central

Fry, Jillian P.; Love, David C.; Shukla, Arunima; Lee, Ryan M.

2014-01-01

Half of the world’s edible seafood comes from aquaculture, and the United States (US) government is working to develop an offshore finfish aquaculture industry in federal waters. To date, US aquaculture has largely been regulated at the state level, and creating an offshore aquaculture industry will require the development of a new regulatory structure. Some aquaculture practices involve hazardous working conditions and the use of veterinary drugs, agrochemicals, and questionable farming methods, which could raise environmental and occupational public health concerns if these methods are employed in the offshore finfish industry in the US. This policy analysis aims to inform public health professionals and other stakeholders in the policy debate regarding how offshore finfish aquaculture should be regulated in the US to protect human health; previous policy analyses on this topic have focused on environmental impacts. We identified 20 federal laws related to offshore finfish aquaculture, including 11 that are relevant to preventing, controlling, or monitoring potential public health risks. Given the novelty of the industry in the US, myriad relevant laws, and jurisdictional issues in an offshore setting, federal agencies need to work collaboratively and transparently to ensure that a comprehensive and functional regulatory structure is established that addresses the potential public health risks associated with this type of food production. PMID:25415208

3-D Simulation of Earthquakes on the Cascadia Megathrust: Key Parameters and Constraints from Offshore Structure and Seismicity

NASA Astrophysics Data System (ADS)

Wirth, E. A.; Frankel, A. D.; Vidale, J. E.; Stone, I.; Nasser, M.; Stephenson, W. J.

2017-12-01

The Cascadia subduction zone has a long history of M8 to M9 earthquakes, inferred from coastal subsidence, tsunami records, and submarine landslides. These megathrust earthquakes occur mostly offshore, and an improved characterization of the megathrust is critical for accurate seismic hazard assessment in the Pacific Northwest. We run numerical simulations of 50 magnitude 9 earthquake rupture scenarios on the Cascadia megathrust, using a 3-D velocity model based on geologic constraints and regional seismicity, as well as active and passive source seismic studies. We identify key parameters that control the intensity of ground shaking and resulting seismic hazard. Variations in the down-dip limit of rupture (e.g., extending rupture to the top of the non-volcanic tremor zone, compared to a completely offshore rupture) result in a 2-3x difference in peak ground acceleration (PGA) for the inland city of Seattle, Washington. Comparisons of our simulations to paleoseismic data suggest that rupture extending to the 1 cm/yr locking contour (i.e., mostly offshore) provides the best fit to estimates of coastal subsidence during previous Cascadia earthquakes, but further constraints on the down-dip limit from microseismicity, offshore geodetics, and paleoseismic evidence are needed. Similarly, our simulations demonstrate that coastal communities experience a four-fold increase in PGA depending upon their proximity to strong-motion-generating areas (i.e., high strength asperities) on the deeper portions of the megathrust. An improved understanding of the structure and rheology of the plate interface and accretionary wedge, and better detection of offshore seismicity, may allow us to forecast locations of these asperities during a future Cascadia earthquake. In addition to these parameters, the seismic velocity and attenuation structure offshore also strongly affects the resulting ground shaking. This work outlines the range of plausible ground motions from an M9 Cascadia earthquake, and highlights the importance of offshore studies for constraining critical parameters and seismic hazard in the Pacific Northwest.

What can wave energy learn from offshore oil and gas?

PubMed

Jefferys, E R

2012-01-28

This title may appear rather presumptuous in the light of the progress made by the leading wave energy devices. However, there may still be some useful lessons to be learnt from current 'offshore' practice, and there are certainly some awful warnings from the past. Wave energy devices and the marine structures used in oil and gas exploration as well as production share a common environment and both are subject to wave, wind and current loads, which may be evaluated with well-validated, albeit imperfect, tools. Both types of structure can be designed, analysed and fabricated using similar tools and technologies. They fulfil very different missions and are subject to different economic and performance requirements; hence 'offshore' design tools must be used appropriately in wave energy project and system design, and 'offshore' cost data should be adapted for 'wave' applications. This article reviews the similarities and differences between the fields and highlights the differing economic environments; offshore structures are typically a small to moderate component of field development cost, while wave power devices will dominate overall system cost. The typical 'offshore' design process is summarized and issues such as reliability-based design and design of not normally manned structures are addressed. Lessons learned from poor design in the past are discussed to highlight areas where care is needed, and wave energy-specific design areas are reviewed. Opportunities for innovation and optimization in wave energy project and device design are discussed; wave energy projects must ultimately compete on a level playing field with other routes to low CO₂ energy and/or energy efficiency. This article is a personal viewpoint and not an expression of a ConocoPhillips position.

Oblique Collision of the Leeward Antilles, Offshore Venezuela: Linking Onshore and Offshore Data from BOLIVAR

NASA Astrophysics Data System (ADS)

Beardsley, A. G.; Avé Lallemant, H. G.; Levander, A.; Clark, S. A.

2006-12-01

The kinematic history of the Leeward Antilles (offshore Venezuela) can be characterized with the integration of onshore outcrop data and offshore seismic reflection data. Deformation structures and seismic interpretation show that oblique convergence and wrench tectonics have controlled the diachronous deformation identified along the Caribbean - South America plate boundary. Field studies of structural features in outcrop indicate one generation of ductile deformation (D1) structures and three generations of brittle deformation (F1 - F3) structures. The earliest deformation (D1/F1) began ~ 110 Ma with oblique convergence between the Caribbean plate and South American plate. The second generation of deformation (F2) structures initiated in the Eocene with the extensive development of strike-slip fault systems along the diffuse plate boundary and the onset of wrench tectonics within a large-scale releasing bend. The most recent deformation (F3) has been observed in the west since the Miocene where continued dextral strike-slip motion has led to the development of a major restraining bend between the Caribbean plate transform fault and the Oca - San Sebastian - El Pilar fault system. Deformation since the late Cretaceous has been accompanied by a total of 135° clockwise rotation. Interpretation of 2D marine reflection data indicates similar onshore and offshore deformation trends. Seismic lines that approximately parallel the coastline (NW-SE striking) show syndepositional normal faulting during F1/F2 and thrust faulting associated with F3. On seismic lines striking NNE-SSW, we interpret inversion of F2 normal faults with recent F3 deformation. We also observe both normal and thrust faults related to F3. The thick sequence of recent basin sedimentation (Miocene - Recent), interpreted from the seismic data, supports the ongoing uplift and erosion of the islands; as suggested by fluid inclusion analysis. Overall, there appears to be a strong correlation between onshore micro- and mesoscopic deformational structures and offshore macro-scale structural features seen in the reflection data. The agreement of features supports our regional deformation and rotation model along the Caribbean - South America obliquely convergent plate boundary.

Observations and a model of undertow over the inner continental shelf

USGS Publications Warehouse

Lentz, Steven J.; Fewings, Melanie; Howd, Peter; Fredericks, Janet; Hathaway, Kent

2008-01-01

Onshore volume transport (Stokes drift) due to surface gravity waves propagating toward the beach can result in a compensating Eulerian offshore flow in the surf zone referred to as undertow. Observed offshore flows indicate that wave-driven undertow extends well offshore of the surf zone, over the inner shelves of Martha’s Vineyard, Massachusetts, and North Carolina. Theoretical estimates of the wave-driven offshore transport from linear wave theory and observed wave characteristics account for 50% or more of the observed offshore transport variance in water depths between 5 and 12 m, and reproduce the observed dependence on wave height and water depth.During weak winds, wave-driven cross-shelf velocity profiles over the inner shelf have maximum offshore flow (1–6 cm s−1) and vertical shear near the surface and weak flow and shear in the lower half of the water column. The observed offshore flow profiles do not resemble the parabolic profiles with maximum flow at middepth observed within the surf zone. Instead, the vertical structure is similar to the Stokes drift velocity profile but with the opposite direction. This vertical structure is consistent with a dynamical balance between the Coriolis force associated with the offshore flow and an along-shelf “Hasselmann wave stress” due to the influence of the earth’s rotation on surface gravity waves. The close agreement between the observed and modeled profiles provides compelling evidence for the importance of the Hasselmann wave stress in forcing oceanic flows. Summer profiles are more vertically sheared than either winter profiles or model profiles, for reasons that remain unclear.

Aeroelastic impact of above-rated wave-induced structural motions on the near-wake stability of a floating offshore wind turbine rotor

NASA Astrophysics Data System (ADS)

Rodriguez, Steven; Jaworski, Justin

2017-11-01

The impact of above-rated wave-induced motions on the stability of floating offshore wind turbine near-wakes is studied numerically. The rotor near-wake is generated using a lifting-line free vortex wake method, which is strongly coupled to a finite element solver for kinematically nonlinear blade deformations. A synthetic time series of relatively high-amplitude/high-frequency representative of above-rated conditions of the NREL 5MW referece wind turbine is imposed on the rotor structure. To evaluate the impact of these above-rated conditions, a linear stability analysis is first performed on the near wake generated by a fixed-tower wind turbine configuration at above-rated inflow conditions. The platform motion is then introduced via synthetic time series, and a stability analysis is performed on the wake generated by the floating offshore wind turbine at the same above-rated inflow conditions. The stability trends (disturbance modes versus the divergence rate of vortex structures) of the two analyses are compared to identify the impact that above-rated wave-induced structural motions have on the stability of the floating offshore wind turbine wake.

Preliminary interpretation of high resolution 3D seismic data from offshore Mt. Etna, Italy

NASA Astrophysics Data System (ADS)

Gross, F.; Krastel, S.; Chiocci, F. L.; Ridente, D.; Cukur, D.; Bialas, J.; Papenberg, C. A.; Crutchley, G.; Koch, S.

2013-12-01

In order to gain knowledge about subsurface structures and its correlation to seafloor expressions, a hydro-acoustic dataset was collected during RV Meteor Cruise M86/2 (December 2011/January 2012) in Messina Straits and offshore Mt. Etna. Especially offshore Mt. Etna, the data reveals an obvious connection between subsurface structures and previously known morphological features at the sea floor. Therefore a high resolution 3D seismic dataset was acquired between Riposto Ridge and Catania Canyon close to the shore of eastern Sicily. The study area is characterized by a major structural high, which hosts several ridge-like features at the seafloor. These features are connected to a SW-NE trending fault system. The ridges are bended in their NE-SW direction and host major escarpments at the seafloor. Furthermore they are located directly next to a massive amphitheater structure offshore Mt. Etna with slope gradients of up to 35°, which is interpreted as remnants of a massive submarine mass wasting event off Sicily. The new 3D seismic dataset allows an in depth analysis of the ongoing deformation of the east flank of Mt. Etna.

Calcareous nannofossil evidence for the existence of the Gulf Stream during the late Maastrichtian

USGS Publications Warehouse

Watkins, D.K.; ,

2005-01-01

Upper Maastrichtian calcareous nannofossil assemblages, from eight cores on the South Carolina Coastal Plain (onshore set) and three deep sea drilling sites from the continental slope and abyssal hills (offshore set), were analyzed by correlation and principal component analysis to examine the ancient surface water thermal structure. In addition, a temperature index derived from independently published paleobiogeographic information was applied to the sample data. All three methods indicate a strong separation of the samples into onshore and offshore sets, with the offshore data set exhibiting significantly warmer paleotemperatures. The great disparity between these two sample sets indicates that there was a strong thermal contrast between the onshore and offshore surface water masses that persisted throughout the late Maastrichtian despite evident shortterm changes in fertility, productivity, and community structure. This suggests the Gulf Stream was present as a major oceanographic feature during the late Maastrichtian. Copyright 2005 by the American Geophysical Union.

Abundance of Corals on Offshore Oil and Gas Platforms in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Kolian, Stephan R.; Sammarco, Paul W.; Porter, Scott A.

2017-08-01

Scleractinian, octocoral, and antipatharian corals have colonized many of the offshore oil and gas platforms in the northern Gulf of Mexico. We surveyed 25 offshore oil and gas platforms for these cnidarians. Few to no corals were detected on inshore, shallow-water structures at <25 m depth; however, the abundance of corals increased, ranging from 14 to 194/m2, on platforms in waters deeper ≥25 m. The most common coral encountered were Tubastraea coccinea (Scleractinia) and Telesto spp. (Octocorallia). The data suggest that the offshore platforms located in waters of >25-30 m in the study area are often colonized by these corals. We recommend that structures located in deeper waters should be surveyed for coral and, if the populations are substantial, consider alternate uses for the retired platforms, and leaving them in place, when feasible.

Abundance of Corals on Offshore Oil and Gas Platforms in the Gulf of Mexico.

PubMed

Kolian, Stephan R; Sammarco, Paul W; Porter, Scott A

2017-08-01

Scleractinian, octocoral, and antipatharian corals have colonized many of the offshore oil and gas platforms in the northern Gulf of Mexico. We surveyed 25 offshore oil and gas platforms for these cnidarians. Few to no corals were detected on inshore, shallow-water structures at <25 m depth; however, the abundance of corals increased, ranging from 14 to 194/m 2 , on platforms in waters deeper ≥25 m. The most common coral encountered were Tubastraea coccinea (Scleractinia) and Telesto spp. (Octocorallia). The data suggest that the offshore platforms located in waters of >25-30 m in the study area are often colonized by these corals. We recommend that structures located in deeper waters should be surveyed for coral and, if the populations are substantial, consider alternate uses for the retired platforms, and leaving them in place, when feasible.

Oil rigs and offshore sport fishing in Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dugas, R.; Guillory, V.; Fischer, M.

Forty years ago, offshore sport fishing in Louisiana was almost nonexistent. Offshore oil drilling platforms are the primary cause of the present increase in sport fishing in this area. Algae and other organisms forming the first step in the food chain cluster around the subsurface structures of the rigs, attracting fish that seek food and shelter. Major game species frequenting these rigs are identified. (3 photos, 22 references, 2 tables)

Nuclear and Mitochondrial Patterns of Population Structure in North Pacific False Killer Whales (Pseudorca crassidens)

DTIC Science & Technology

2014-05-14

microsatellite loci from 206 individuals to examine levels of differentiation among the 2 island-associated populations and offshore animals from the...they are from offshore animals . The patterns of differentiation revealed by the 2 marker types suggest that the island-associated false killer whale...False killer whales (Pseudorca crassidens) are large delphinids typically found in deep water far offshore . However, in the Hawaiian Archipelago

Investigation on the effect of geometrical and geotechnical parameters on elongated offshore piles using fuzzy inference systems

NASA Astrophysics Data System (ADS)

Aminfar, Ali; Mojtahedi, Alireza; Ahmadi, Hamid; Aminfar, Mohammad Hossain

2017-06-01

Among numerous offshore structures used in oil extraction, jacket platforms are still the most favorable ones in shallow waters. In such structures, log piles are used to pin the substructure of the platform to the seabed. The pile's geometrical and geotechnical properties are considered as the main parameters in designing these structures. In this study, ANSYS was used as the FE modeling software to study the geometrical and geotechnical properties of the offshore piles and their effects on supporting jacket platforms. For this purpose, the FE analysis has been done to provide the preliminary data for the fuzzy-logic post-process. The resulting data were implemented to create Fuzzy Inference System (FIS) classifications. The resultant data of the sensitivity analysis suggested that the orientation degree is the main factor in the pile's geometrical behavior because piles which had the optimal operational degree of about 5° are more sustained. Finally, the results showed that the related fuzzified data supported the FE model and provided an insight for extended offshore pile designs.

Offshore oil in the Alaskan Arctic

NASA Technical Reports Server (NTRS)

Weeks, W. F.; Weller, G.

1984-01-01

Oil and gas deposits in the Alaskan Arctic are estimated to contain up to 40 percent of the remaining undiscovered crude oil and oil-equivalent natural gas within U.S. jurisdiction. Most (65 to 70 percent) of these estimated reserves are believed to occuur offshore beneath the shallow, ice-covered seas of the Alaskan continental shelf. Offshore recovery operations for such areas are far from routine, with the primary problems associated with the presence of ice. Some problems that must be resolved if efficient, cost-effective, environmentally safe, year-round offshore production is to be achieved include the accurate estimation of ice forces on offshore structures, the proper placement of pipelines beneath ice-produced gouges in the sea floor, and the cleanup of oil spills in pack ice areas.

Floating Offshore Wind in Hawaii: Potential for Jobs and Economic Impacts from Three Future Scenarios

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jimenez, Tony; Keyser, David; Tegen, Suzanne

Construction of the first offshore wind power plant in the United States began in 2015, off the coast of Rhode Island, using fixed platform structures that are appropriate for shallow seafloors, like those located off the East Coast and mid-Atlantic. However, floating platforms, which have yet to be deployed commercially, will likely need to be anchored to the deeper seafloor if deployed in Hawaiian waters. To analyze the employment and economic potential for floating offshore wind off Hawaii's coasts, the Bureau of Ocean Energy Management commissioned the National Renewable Energy Laboratory (NREL) to analyze two hypothetical deployment scenarios for Hawaii:more » 400 MW of offshore wind by 2050 and 800 MW of offshore wind by 2050. The results of this analysis can be used to better understand the general scale of economic opportunities that could result from offshore wind development.« less

Nonconsensual clinical trials: a foreseeable risk of offshoring under global corporatism.

PubMed

Spielman, Bethany

2015-03-01

This paper explores the connection of offshoring and outsourcing to nonconsensual global pharmaceutical trials in low-income countries. After discussing reasons why the topic of nonconsensual offshored clinical trials may be overlooked in bioethics literature, I suggest that when pharmaceutical corporations offshore clinical trials today, nonconsensual experiments are often foreseeable and not simply the result of aberrant ethical conduct by a few individuals. Offshoring of clinical trials is structured so that experiments can be presented as health care in a unique form of outsourcing from the host country to pharmaceutical corporations. Bioethicists' assessments of the risks and potential benefits of offshore corporate pharmaceutical trials should therefore systematically include not only the hoped for benefits and the risks of the experimental drug but also the risk that subjects will not have consented, as well as the broader international consequences of nonconsensual experimentation.

Advanced Fabrication Processes for Superconducting Very Large Scale Integrated Circuits

DTIC Science & Technology

2015-10-13

transistors. There are several reasons for this gigantic disparity: insufficient funding and lack of profit-driven investments in superconductor ...Inductance of circuit structures for MIT LL superconductor electronics fabrication process with 8 niobium layers,” IEEE Trans. Appl. Supercond., vol...vol. 25, No. 3, 1301704, June 2015. [7] V. Ambegaokar and A. Baratoff, “Tunneling between superconductors ,” Phys. Rev. Lett., vol. 10, no. 11, pp

Design Calculations 93’ MLW Structure East Coast Air Combat Maneuvering Range Offshore Kitty Hawk, North Carolina.

DTIC Science & Technology

1976-09-01

CALCULATIONS 93’ MLW PLATFORM EAST COAST AIR COMBAT MANEUVERING RANGE OFFSHORE KITTY HAWK, NORTH CAROLINA CONTRACT NO. N62477-76-C-0179 MODIFICATION NO. P0001...of structures comprising the U.S. Navy East Coast Air Combat Maneuvering Range. Its purpose is to provide a platform to support electronic...All portions of the platform above elevation (-) 4.0 feet will be painted. 2. All main structural members located within the splash zone will have an

A Comprehensive Structural Study of Offshore Wind Turbine Foundation and Non-Model Based Damage Detection using Effective Mass with Application to Small Components/ Cables and a Truss Wind Turbine Tower

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Scott A.

This research has two areas of focus. The first area is to investigate offshore wind turbine (OWT) designs, for use in the Maryland offshore wind area (MOWA), using intensive modeling techniques. The second focus area is to investigate a way to detect damage in wind turbine towers and small electrical components.

Foundations for offshore wind turbines.

PubMed

Byrne, B W; Houlsby, G T

2003-12-15

An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers.

Optimisation and evaluation of pre-design models for offshore wind turbines with jacket support structures and their influence on integrated load simulations

NASA Astrophysics Data System (ADS)

Schafhirt, S.; Kaufer, D.; Cheng, P. W.

2014-12-01

In recent years many advanced load simulation tools, allowing an aero-servo-hydroelastic analyses of an entire offshore wind turbine, have been developed and verified. Nowadays, even an offshore wind turbine with a complex support structure such as a jacket can be analysed. However, the computational effort rises significantly with an increasing level of details. This counts especially for offshore wind turbines with lattice support structures, since those models do naturally have a higher number of nodes and elements than simpler monopile structures. During the design process multiple load simulations are demanded to obtain an optimal solution. In the view of pre-design tasks it is crucial to apply load simulations which keep the simulation quality and the computational effort in balance. The paper will introduce a reference wind turbine model consisting of the REpower5M wind turbine and a jacket support structure with a high level of detail. In total twelve variations of this reference model are derived and presented. Main focus is to simplify the models of the support structure and the foundation. The reference model and the simplified models are simulated with the coupled simulation tool Flex5-Poseidon and analysed regarding frequencies, fatigue loads, and ultimate loads. A model has been found which reaches an adequate increase of simulation speed while holding the results in an acceptable range compared to the reference results.

46 CFR 107.211 - Original Certificate of Inspection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Original Certificate of Inspection. 107.211 Section 107.211 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS... Offshore Drilling Units” (Appendix A). Existing structure, arrangements, materials, equipment, and...

46 CFR 107.211 - Original Certificate of Inspection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Original Certificate of Inspection. 107.211 Section 107.211 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS... Offshore Drilling Units” (Appendix A). Existing structure, arrangements, materials, equipment, and...

46 CFR 107.211 - Original Certificate of Inspection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Original Certificate of Inspection. 107.211 Section 107.211 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS... Offshore Drilling Units” (Appendix A). Existing structure, arrangements, materials, equipment, and...

46 CFR 107.211 - Original Certificate of Inspection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Original Certificate of Inspection. 107.211 Section 107.211 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS... Offshore Drilling Units” (Appendix A). Existing structure, arrangements, materials, equipment, and...

46 CFR 107.211 - Original Certificate of Inspection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Original Certificate of Inspection. 107.211 Section 107.211 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS... Offshore Drilling Units” (Appendix A). Existing structure, arrangements, materials, equipment, and...

High-resolution computational algorithms for simulating offshore wind turbines and farms: Model development and validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calderer, Antoni; Yang, Xiaolei; Angelidis, Dionysios

2015-10-30

The present project involves the development of modeling and analysis design tools for assessing offshore wind turbine technologies. The computational tools developed herein are able to resolve the effects of the coupled interaction of atmospheric turbulence and ocean waves on aerodynamic performance and structural stability and reliability of offshore wind turbines and farms. Laboratory scale experiments have been carried out to derive data sets for validating the computational models.

Arctic ice islands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sackinger, W.M.; Jeffries, M.O.; Lu, M.C.

1988-01-01

The development of offshore oil and gas resources in the Arctic waters of Alaska requires offshore structures which successfully resist the lateral forces due to moving, drifting ice. Ice islands are floating, a tabular icebergs, up to 60 meters thick, of solid ice throughout their thickness. The ice islands are thus regarded as the strongest ice features in the Arctic; fixed offshore structures which can directly withstand the impact of ice islands are possible but in some locations may be so expensive as to make oilfield development uneconomic. The resolution of the ice island problem requires two research steps: (1)more » calculation of the probability of interaction between an ice island and an offshore structure in a given region; and (2) if the probability if sufficiently large, then the study of possible interactions between ice island and structure, to discover mitigative measures to deal with the moving ice island. The ice island research conducted during the 1983-1988 interval, which is summarized in this report, was concerned with the first step. Monte Carlo simulations of ice island generation and movement suggest that ice island lifetimes range from 0 to 70 years, and that 85% of the lifetimes are less then 35 years. The simulation shows a mean value of 18 ice islands present at any time in the Arctic Ocean, with a 90% probability of less than 30 ice islands. At this time, approximately 34 ice islands are known, from observations, to exist in the Arctic Ocean, not including the 10-meter thick class of ice islands. Return interval plots from the simulation show that coastal zones of the Beaufort and Chukchi Seas, already leased for oil development, have ice island recurrences of 10 to 100 years. This implies that the ice island hazard must be considered thoroughly, and appropriate safety measures adopted, when offshore oil production plans are formulated for the Alaskan Arctic offshore. 132 refs., 161 figs., 17 tabs.« less

[Medical Emergency Preparedness in offshore wind farms : New challenges in the german north and baltic seas].

PubMed

Stuhr, M; Dethleff, D; Weinrich, N; Nielsen, M; Hory, D; Kowald, B; Seide, K; Kerner, T; Nau, C; Jürgens, C

2016-05-01

Offshore windfarms are constructed in the German North and Baltic Seas. The off-coast remoteness of the windfarms, particular environmental conditions, limitations in offshore structure access, working in heights and depths, and the vast extent of the offshore windfarms cause significant challenges for offshore rescue. Emergency response systems comparable to onshore procedures are not fully established yet. Further, rescue from offshore windfarms is not part of the duty of the German Maritime Search and Rescue Organization or SAR-Services due to statute and mandate reasons. Scientific recommendations or guidelines for rescue from offshore windfarms are not available yet. The present article reflects the current state of medical care and rescue from German offshore windfarms and related questions. The extended therapy-free interval until arrival of the rescue helicopter requires advanced first-aid measures as well as improved first-aider qualification. Rescue helicopters need to be equipped with a winch system in order to dispose rescue personnel on the wind turbines, and to hoist-up patients. For redundancy reasons and for conducting rendezvous procedures, adequate sea-bound rescue units need to be provided. In the light of experiences from the offshore oil and gas industry and first offshore wind analyses, the availability of professional medical personnel in offshore windfarms seems advisible. Operational air medical rescue services and specific offshore emergency reaction teams have established a powerful rescue chain. Besides the present development of medical standards, more studies are necessary in order to place the rescue chain on a long-term, evidence-based groundwork. A central medical offshore registry may help to make a significant contribution at this point.

New Insights on the Structure of the Cascadia Subduction Zone from Amphibious Seismic Data

NASA Astrophysics Data System (ADS)

Janiszewski, Helen Anne

A new onshore-offshore seismic dataset from the Cascadia subduction zone was used to characterize mantle lithosphere structure from the ridge to the volcanic arc, and plate interface structure offshore within the seismogenic zone. The Cascadia Initiative (CI) covered the Juan de Fuca plate offshore the northwest coast of the United States with an ocean bottom seismometer (OBS) array for four years; this was complemented by a simultaneous onshore seismic array. Teleseismic data recorded by this array allows the unprecedented imaging of an entire tectonic plate from its creation at the ridge through subduction initiation and back beyond the volcanic arc along the entire strike of the Cascadia subduction zone. Higher frequency active source seismic data also provides constraints on the crustal structure along the plate interface offshore. Two seismic datasets were used to image the plate interface structure along a line extending 100 km offshore central Washington. These are wide-angle reflections from ship-to-shore seismic data from the Ridge-To-Trench seismic cruise and receiver functions calculated from a densely spaced CI OBS focus array in a similar region. Active source seismic observations are consistent with reflections from the plate interface offshore indicating the presence of a P-wave velocity discontinuity. Until recently, there has been limited success in using the receiver function technique on OBS data. I avoid these traditional challenges by using OBS constructed with shielding deployed in shallow water on the continental shelf. These data have quieter horizontals and avoid water- and sediment-multiple contamination at the examined frequencies. The receiver functions are consistently modeled with a velocity structure that has a low velocity zone (LVZ) with elevated P to S-wave velocity ratios at the plate interface. A similar LVZ structure has been observed onshore and interpreted as a combination of elevated pore-fluid pressures or metasediments. This new offshore result indicates that the structure may persist updip indicating the plate interface may be weak. To focus more broadly on the entire subduction system, I calculate phase velocities from teleseismic Rayleigh waves from 20-100 s period across the entire onshore-offshore array. The shear-wave velocity model calculated from these data can provide constrains on the thermal structure of the lithosphere both prior to and during subduction of the Juan de Fuca plate. Using OBS data in this period band requires removal of tilt and compliance noise, two types of water-induced noise that affect long period data. To facilitate these corrections on large seismic arrays such as the CI, an automated quality control routine was developed for selecting noise windows for the calculation of the required transfer functions. These corrections typically involve either averaging out transient signals, which requires the assumption of stationarity of the noise over the long periods of time, or laborious hand selection of noise segments. This new method calculates transfer functions based on daily time series that exclude transient signals, but allows for the investigation of long-term variation over the course of an instrument's deployment. I interpret these new shoreline-crossing phase velocity maps in terms of the tectonics associated with the Cascadia subduction system. Major findings include that oceanic plate cooling models do not explain the velocities observed beneath the Juan de Fuca plate, that slow velocities in the forearc appear to be more prevalent in areas modeled to have experienced high slip in past Cascadia megathrust earthquakes, and along strike variations in phase velocity reflect variations in arc structure and backarc tectonics.

Moment tensor inversion of the 2016 southeast offshore Mie earthquake in the Tonankai region using a three-dimensional velocity structure model: effects of the accretionary prism and subducting oceanic plate

NASA Astrophysics Data System (ADS)

Takemura, Shunsuke; Kimura, Takeshi; Saito, Tatsuhiko; Kubo, Hisahiko; Shiomi, Katsuhiko

2018-03-01

The southeast offshore Mie earthquake occurred on April 1, 2016 near the rupture area of the 1944 Tonankai earthquake, where seismicity around the interface of the Philippine Sea plate had been very low until this earthquake. Since this earthquake occurred outside of seismic arrays, the focal mechanism and depth were not precisely constrained using a one-dimensional velocity model, as in a conventional approach. We conducted a moment tensor inversion of this earthquake by using a three-dimensional velocity structure model. Before the analysis of observed data, we investigated the effects of offshore heterogeneous structures such as the seawater, accretionary prism, and subducting oceanic plate by using synthetic seismograms in a full three-dimensional model and simpler models. The accretionary prism and subducting oceanic plate play important roles in the moment tensor inversion for offshore earthquakes in the subduction zone. Particularly, the accretionary prism, which controls the excitation and propagation of long-period surface waves around the offshore region, provides better estimations of the centroid depths and focal mechanisms of earthquakes around the Nankai subduction zone. The result of moment tensor inversion for the 2016 southeast offshore Mie earthquake revealed low-angle thrust faulting with a moment magnitude of 5.6. According to geophysical surveys in the Nankai Trough, our results suggest that the rupture of this earthquake occurred on the interface of the Philippine Sea plate, rather than on a mega-splay fault. Detailed comparisons of first-motion polarizations provided additional constraints of the rupture that occurred on the interface of the Philippine Sea plate.

Analysis of Tide and Offshore Storm-Induced Water Table Fluctuations for Structural Characterization of a Coastal Island Aquifer

NASA Astrophysics Data System (ADS)

Trglavcnik, Victoria; Morrow, Dean; Weber, Kela P.; Li, Ling; Robinson, Clare E.

2018-04-01

Analysis of water table fluctuations can provide important insight into the hydraulic properties and structure of a coastal aquifer system including the connectivity between the aquifer and ocean. This study presents an improved approach for characterizing a permeable heterogeneous coastal aquifer system through analysis of the propagation of the tidal signal, as well as offshore storm pulse signals through a coastal aquifer. Offshore storms produce high wave activity, but are not necessarily linked to significant onshore precipitation. In this study, we focused on offshore storm events during which no onshore precipitation occurred. Extensive groundwater level data collected on a sand barrier island (Sable Island, NS, Canada) show nonuniform discontinuous propagation of the tide and offshore storm pulse signals through the aquifer with isolated inland areas showing enhanced response to both oceanic forcing signals. Propagation analysis suggests that isolated inland water table fluctuations may be caused by localized leakage from a confined aquifer that is connected to the ocean offshore but within the wave setup zone. Two-dimensional groundwater flow simulations were conducted to test the leaky confined-unconfined aquifer conceptualization and to identify the effect of key parameters on tidal signal propagation in leaky confined-unconfined coastal aquifers. This study illustrates that analysis of offshore storm signal propagation, in addition to tidal signal propagation, provides a valuable and low resource approach for large-scale characterization of permeable heterogeneous coastal aquifers. Such an approach is needed for the effective management of coastal environments where water resources are threatened by human activities and the changing climate.

Twelve years in offshore for Doris C. G

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-04-12

The offshore engineering operations of Doris have included the design of concrete and steel offshore structures, the design and construction of diving and underwater equipment, offshore equipment, vessels, and heavy mooring systems, and the design and installation of pipelines and risers. The company has also engaged in pipelaying, marine operations, diving, and inspection and maintenance work. Some achievements in 1978 were the completion, tow-out, and installation of the Ninian central platform and the design of an additional riser for the Frigg field manifold compression platform to connect the Piper field to the Frigg gas pipeline. The articulated gravity tower formore » concrete platforms was certified by Norsk Veritas in 1978, but fatigue tests on the articulating ball joint are continuing. New designs include the fixed gravity structure with removable floats, which makes the substructure much smaller, so that concrete platforms become economically feasible in water depths previously considered prohibitive, and the steel-and-concrete hybrid platform, which has been fully developed and certified as safe and economical.« less

Stakeholders Opinions on Multi-Use Deep Water Offshore Platform in Hsiao-Liu-Chiu, Taiwan

PubMed Central

Sie, Ya-Tsune; Chang, Yang-Chi; Lu, Shiau-Yun

2018-01-01

This paper describes a group model building activity designed to elicit the potential effects a projected multi-use deep water offshore platform may have on its local environment, including ecological and socio-economic issues. As such a platform is proposed for construction around the island of Hsiao-Liu-Chiu, Taiwan, we organized several meetings with the local stakeholders and structured the debates using group modeling methods to promote consensus. During the process, the participants iteratively built and revised a causal-loop diagram that summarizes their opinions. Overall, local stakeholders concluded that a multi-use deep water offshore marine platform might have beneficial effects for Hsiao-Liu-Chiu because more tourists and fish could be attracted by the structure, but they also raised some potential problems regarding the law in Taiwan and the design of the offshore platform, especially its resistance to extreme weather. We report the method used and the main results and insights gained during the process. PMID:29415521

Automatic control and monitoring equipment for cathodic protection of offshore structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, J.H.

1979-10-01

The preferred cathodic-protection systems for offshore structures are (1) the sacrificial-anode form for areas where the anode's weight or wave resistance is not a serious handicap and (2) a combined anode/impressed-current system that reduces the anode mass. Problems associated with controlling and monitoring the equipment are related to the anode locations, suitability of the reference electrodes, instrumentation requirements, interpretation of the measured potentials, and influence of water depth.

Development and Verification of the Soil-Pile Interaction Extension for SubDyn

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damiani, Rick R; Wendt, Fabian F

SubDyn is the substructure structural-dynamics module for the aero-hydro-servo-elastic tool FAST v8. SubDyn uses a finite-element model (FEM) to simulate complex multimember lattice structures connected to conventional turbines and towers, and it can make use of the Craig-Bampton model reduction. Here we describe the newly added capability to handle soil-pile stiffness and compare results for monopile and jacket-based offshore wind turbines as obtained with FAST v8, SACS, and EDP (the latter two are modeling software packages commonly used in the offshore oil and gas industry). The level of agreement in terms of modal properties and loads for the entire offshoremore » wind turbine components is excellent, thus allowing SubDyn and FAST v8 to accurately simulate offshore wind turbines on fixed-bottom structures and accounting for the effect of soil dynamics, thus reducing risk to the project.« less

Response spectrum method for extreme wave loading with higher order components of drag force

NASA Astrophysics Data System (ADS)

Reza, Tabeshpour Mohammad; Mani, Fatemi Dezfouli; Ali, Dastan Diznab Mohammad; Saied, Mohajernasab; Saied, Seif Mohammad

2017-03-01

Response spectra of fixed offshore structures impacted by extreme waves are investigated based on the higher order components of the nonlinear drag force. In this way, steel jacket platforms are simplified as a mass attached to a light cantilever cylinder and their corresponding deformation response spectra are estimated by utilizing a generalized single degree of freedom system. Based on the wave data recorded in the Persian Gulf region, extreme wave loading conditions corresponding to different return periods are exerted on the offshore structures. Accordingly, the effect of the higher order components of the drag force is considered and compared to the linearized state for different sea surface levels. When the fundamental period of the offshore structure is about one third of the main period of wave loading, the results indicate the linearized drag term is not capable of achieving a reliable deformation response spectrum.

Observations from Space: Marine Ecosystem and Environment Response to Typhoon/ Hurricanes

NASA Astrophysics Data System (ADS)

Tang, Danling; Yi, Sui

Marine ecosystem is sensitive to environmental factors, including typhoon. Typhoon's activities have been strengthening in both intensity and spatial coverage in the past several decades, along with global changes; however, our knowledge about the impact of typhoons upon the marine ecosystem is very scarce. To understand how could typhoon/hurricane impact on marine ecosystem, we have conducted a series studies in the South China Sea, by using Satellite remote sensing and in situ observation data to investigate phytoplankton concentration, sea surface temperature (SST) and related factors before, during, and after typhoon. Results show that typhoon can induce large area of phytoplankton blooms with increases of Chlorophyll a (Chl a) concentrations and decrease of sea surface temperature (SST) about 4 oC. Analysis showed that typhoon can support nutrients to surface phytoplankton by upwelling and vertical mixing, and typhoon rain can also nourish marine phytoplankton. More observations confirmed that typhoon can induce cold eddy, and cold eddy can support eddy-shape phyto-plankton bloom by upwelling. Typhoon can also induce transport of nutrient-rich water from depth and from the coast to offshore regions, nourishing phytoplankton biomass. Comparative study show that slow-moving typhoon induced phytoplankton blooms of higher Chlorophyll-a (Chl-a), the strong typhoon induced phytoplankton blooms of a large area. Therefore, typhoons may have important contribution to the marine primary production. Those studies may help better understand the mechanism of typhoon impacts on marine ecosys-tem, and the role of typhoon in the global environmental changes. The series research were sup-ported by: NSFC (40976091, 40811140533) and GD NSF (8351030101000002); (2) CAS(kzcx2-yw-226 and LYQ200701); (3) The CAS/SAFEA International Partnership Program for Creative Research Teams (KZCX2-YW-T001). References: Tang, DanLing, H Kawamura, P Shi, W Takahashi, T Shimada, F. Sakaida, O Isoguchi, 2005. Seasonal phytoplankton blooms associated with monsoonal influences and coastal environments in the sea areas either side of the Indochina Peninsula. JGR-Bio-geo. VOL. 111, G01010, doi:10.1029/2005JG000050, 2006. Tang, DanLing, H Kawamura, Hai Doan-Nhu, W Takahashi , 2004. Remote sensing oceanography of a harmful algal bloom (HAB) off the coast of southeastern Vietnam. J. of Geophysical Research (Ocean).Vol 109, doi:10.1029/2003JC002045; Tang, DanLing, H Kawamura, TV Dien. MA Lee, 2004. Offshore phytoplankton biomass increase and its oceanographic causes in the South China Sea. Marine Ecology Progress Series, 268: 31-41; Tang, DanLing, H ZHAO, B. Satyanarayana, GM ZHENG, RP. SINGH, JH LV, 2009, Enhancement of Chlorophyll-a in the Northeastern Indian Ocean after the 2004 South Asian Tsunami, Int. J. Remote Sensing doi10.1080/01431160802603778 , Vol.30 (17):4553-4565; Zhao, H., DanLing Tang, and Y. Wang, 2008, Comparison of phyto-plankton blooms triggered by two typhoons with different intensities and translation speeds in the South China SeaMar Ecol Prog Ser, 365, 57-65; Zheng, GM. and DanLing Tang ,2007Off-shore and nearshore chlorophyll increases induced by typhoon winds and subsequent terrestrial rainwater runoff, Mar Ecol Prog Ser, 333, 61-72; H Zhao, DanLing TANG, DX Wang, 2009, Phytoplankton blooms near the Pearl River Estuary induced by Typhoon Nuri, Journal of Geophysical Research -Oceans. 114, C12027; YQ Chen, DanLing Tang, 2010, Cold eddies and eddy-shape phytoplankton blooms induced by tropical cyclone Linfa in the South China Sea. In preparation; XX Yang, DanLing Tang, 2010, Sea Surface Temperature Decreasing in the Northern South China Sea Induced by Typhoon. In preparation.

Metocean Data Needs Assessment for U.S. Offshore Wind Energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, Bruce H.; Filippelli, Matthew; Baker, Matthew

2015-01-01

A potential barrier to developing offshore wind energy in the United States is the general lack of accurate information in most offshore areas about the wind resource characteristics and external metocean design conditions at the heights and depths relevant to wind turbines and their associated structures and components. Knowledge of these conditions enables specification of the appropriate design basis for wind turbine structures and components so they can withstand the loads expected over a project’s lifetime. Human safety, vessel navigation, and project construction and maintenance activities are equally tied to the metocean environment. Currently, metocean data is sparse in potentialmore » development areas and even when available, does not include the detail or quality required to make informed decisions.« less

Characterization of the Hosgri Fault Zone and adjacent structures in the offshore Santa Maria Basin, south-central California: Chapter CC of Evolution of sedimentary basins/onshore oil and gas investigations - Santa Maria province

USGS Publications Warehouse

Willingham, C. Richard; Rietman, Jan D.; Heck, Ronald G.; Lettis, William R.

2013-01-01

The Hosgri Fault Zone trends subparallel to the south-central California coast for 110 km from north of Point Estero to south of Purisima Point and forms the eastern margin of the present offshore Santa Maria Basin. Knowledge of the attributes of the Hosgri Fault Zone is important for petroleum development, seismic engineering, and environmental planning in the region. Because it lies offshore along its entire reach, our characterizations of the Hosgri Fault Zone and adjacent structures are primarily based on the analysis of over 10,000 km of common-depth-point marine seismic reflection data collected from a 5,000-km2 area of the central and eastern parts of the offshore Santa Maria Basin. We describe and illustrate the along-strike and downdip geometry of the Hosgri Fault Zone over its entire length and provide examples of interpreted seismic reflection records and a map of the structural trends of the fault zone and adjacent structures in the eastern offshore Santa Maria Basin. The seismic data are integrated with offshore well and seafloor geologic data to describe the age and seismic appearance of offshore geologic units and marker horizons. We develop a basin-wide seismic velocity model for depth conversions and map three major unconformities along the eastern offshore Santa Maria Basin. Accompanying plates include maps that are also presented as figures in the report. Appendix A provides microfossil data from selected wells and appendix B includes uninterpreted copies of the annotated seismic record sections illustrated in the chapter. Features of the Hosgri Fault Zone documented in this investigation are suggestive of both lateral and reverse slip. Characteristics indicative of lateral slip include (1) the linear to curvilinear character of the mapped trace of the fault zone, (2) changes in structural trend along and across the fault zone that diminish in magnitude toward the ends of the fault zone, (3) localized compressional and extensional structures characteristic of constraining and releasing bends and stepovers, (4) changes in the sense and magnitude of vertical separation along strike within the fault zone, and (5) changes in downdip geometry between the major traces and segments of the fault zone. Characteristics indicative of reverse slip include (1) reverse fault geometries that occur across major strands of the fault zone and (2) fault-bend folds and localized thrust faults that occur along the northern and southern reaches of the fault. Analyses of high-resolution, subbottom profiler and side-scan sonar records indicate localized Holocene activity along most of the extent of the fault zone. Collectively, these features are the basis of our characterization of the Hosgri Fault Zone as an active, 110-km-long, convergent right-oblique slip (transpressional) fault with identified northern and southern terminations. This interpretation is consistent with recently published analyses of onshore geologic data, regional tectonic kinematic models, and instrumental seismicity.

Healthy offshore workforce? A qualitative study on offshore wind employees' occupational strain, health, and coping.

PubMed

Mette, Janika; Velasco Garrido, Marcial; Harth, Volker; Preisser, Alexandra M; Mache, Stefanie

2018-01-23

Offshore work has been described as demanding and stressful. Despite this, evidence regarding the occupational strain, health, and coping behaviors of workers in the growing offshore wind industry in Germany is still limited. The purpose of our study was to explore offshore wind employees' perceptions of occupational strain and health, and to investigate their strategies for dealing with the demands of offshore work. We conducted 21 semi-structured telephone interviews with employees in the German offshore wind industry. The interviews were transcribed and analyzed in a deductive-inductive approach following Mayring's qualitative content analysis. Workers generally reported good mental and physical health. However, they also stated perceptions of stress at work, fatigue, difficulties detaching from work, and sleeping problems, all to varying extents. In addition, physical health impairment in relation to offshore work, e.g. musculoskeletal and gastrointestinal complaints, was documented. Employees described different strategies for coping with their job demands. The strategies comprised of both problem and emotion-focused approaches, and were classified as either work-related, health-related, or related to seeking social support. Our study is the first to investigate the occupational strain, health, and coping of workers in the expanding German offshore wind industry. The results offer new insights that can be utilized for future research in this field. In terms of practical implications, the findings suggest that measures should be carried out aimed at reducing occupational strain and health impairment among offshore wind workers. In addition, interventions should be initiated that foster offshore wind workers' health and empower them to further expand on effective coping strategies at their workplace.

"It's still a great adventure" - exploring offshore employees' working conditions in a qualitative study.

PubMed

Mette, Janika; Velasco Garrido, Marcial; Harth, Volker; Preisser, Alexandra M; Mache, Stefanie

2017-01-01

Despite the particular demands inherent to offshore work, little is known about the working conditions of employees in the German offshore wind industry. To date, neither offshore employees' job demands and resources, nor their needs for improving the working conditions have been explored. Therefore, the aim of this study was to conduct a qualitative analysis to gain further insight into these topics. Forty-two semi-structured telephone interviews with German offshore employees ( n  = 21) and offshore experts ( n  = 21) were conducted. Employees and experts were interviewed with regard to their perceptions of their working conditions offshore. In addition, employees were asked to identify areas with potential need for improvement. The interviews were analysed in a deductive-inductive process according to Mayring's qualitative content analysis. Employees and experts reported various demands of offshore work, including challenging physical labour, long shifts, inactive waiting times, and recurrent absences from home. In contrast, the high personal meaning of the work, regular work schedule (14 days offshore, 14 days onshore), and strong comradeship were highlighted as job resources. Interviewees' working conditions varied considerably, e.g. regarding their work tasks and accommodations. Most of the job demands were perceived in terms of the work organization and living conditions offshore. Likewise, employees expressed the majority of needs for improvement in these areas. Our study offers important insight into the working conditions of employees in the German offshore wind industry. The results can provide a basis for further quantitative research in order to generalize the findings. Moreover, they can be utilized to develop needs-based interventions to improve the working conditions offshore.

Extensional Tectonics and Sedimentary Architecture Using 3-D Seismic Data: An Example from Hydrocarbon-Bearing Mumbai Offshore Basin, West Coast of India

NASA Astrophysics Data System (ADS)

Mukhopadhyay, D. K.; Bhowmick, P. K.; Mishra, P.

2016-12-01

In offshore sedimentary basins, analysis of 3-D seismic data tied with well log data can be used to deduce robust isopach and structure contour maps of different stratigraphic formations. The isopach maps give depocenters whereas structure contour maps give structural relief at a specific time. Combination of these two types of data helps us decipher horst-graben structures, sedimentary basin architecture and tectono-stratigraphic relations through Tertiary time. Restoration of structural cross sections with back-stripping of successively older stratigraphic layers leads to better understand tectono-sedimentary evolution of a basin. The Mumbai (or Bombay) Offshore Basin is the largest basin off the west coast of India and includes Bombay High giant oil/gas field. Although this field was discovered in 1974 and still producing, the basin architecture vis-à-vis structural evolution are not well documented. We take the approach briefly outlined above to study in detail three large hydrocarbon-bearing structures located within the offshore basin. The Cretaceous Deccan basalt forms the basement and hosts prodigal thickness (> 8 km at some localities) of Tertiary sedimentary formations.A two stage deformation is envisaged. At the first stage horst and graben structures formed due to approximately E-W extensional tectonics. This is most spectacularly seen at the basement top level. The faults associated with this extension strike NNW. At the second stage of deformation a set of ENE-striking cross faults have developed leading to the formation of transpressional structures at places. High rate of early sedimentation obliterated horst-graben architecture to large extent. An interesting aspect emerges is that the all the large-scale structures have rather low structural relief. However, the areal extent of such structures are very large. Consequently, these structures hold commercial quantities of oil/gas.

Deposition model of a Miocene barred wave- and storm-dominated shoreface and shelf, southeastern Malay basin, offshore west Malaysia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramli, N.

1986-01-01

The J sandstone is an important hydrocarbon-bearing reservoir in the southeastern part of the Malay basin. The lower and upper members of the J sandstone are composed of shoreface and offshore sediments. The shoreface sequence contains depositional structures characteristic of a barred wave- and storm-dominated shoreface. Each shoreface sequence is laterally associated with a series of stacked offshore bars. Offshore bars can be subdivided into proximal and distal types. Two types of proximal offshore bars have been identified: (1) proximal bars formed largely above fair-weather wave base (inner proximal bars), and (2) proximal bars formed below fair-weather wave base (outermore » proximal bars). The inner proximal bars are closely associated with the shoreface sequence and are similar to the middle and lower shoreface. The presence of poorly sorted, polymodal, very fine to very coarse-grained sandstone beneath well-sorted crestal sandstones of inner proximal bars suggests that these offshore bars may have been deposited rapidly by storms. The crests of the inner proximal offshore bars were subsequently reworked by fair-weather processes, and the crests of the outer proximal and distal offshore bars were reworked by waning storm currents and oscillatory waves. Thick marine shales overlying offshore bars contain isolated sheet sandstones. Each sheet sandstone exhibits features that may be characteristic of distal storm shelf deposits. 15 figures, 2 tables.« less

Simplified Technique for Predicting Offshore Pipeline Expansion

NASA Astrophysics Data System (ADS)

Seo, J. H.; Kim, D. K.; Choi, H. S.; Yu, S. Y.; Park, K. S.

2018-06-01

In this study, we propose a method for estimating the amount of expansion that occurs in subsea pipelines, which could be applied in the design of robust structures that transport oil and gas from offshore wells. We begin with a literature review and general discussion of existing estimation methods and terminologies with respect to subsea pipelines. Due to the effects of high pressure and high temperature, the production of fluid from offshore wells is typically caused by physical deformation of subsea structures, e.g., expansion and contraction during the transportation process. In severe cases, vertical and lateral buckling occurs, which causes a significant negative impact on structural safety, and which is related to on-bottom stability, free-span, structural collapse, and many other factors. In addition, these factors may affect the production rate with respect to flow assurance, wax, and hydration, to name a few. In this study, we developed a simple and efficient method for generating a reliable pipe expansion design in the early stage, which can lead to savings in both cost and computation time. As such, in this paper, we propose an applicable diagram, which we call the standard dimensionless ratio (SDR) versus virtual anchor length (L A ) diagram, that utilizes an efficient procedure for estimating subsea pipeline expansion based on applied reliable scenarios. With this user guideline, offshore pipeline structural designers can reliably determine the amount of subsea pipeline expansion and the obtained results will also be useful for the installation, design, and maintenance of the subsea pipeline.

Evaluating stress analysis and failure criteria for offshore structures for Pechora Sea conditions

NASA Astrophysics Data System (ADS)

Nesic, S.; Donskoy, Y.; Zolotukhin, A.

2017-12-01

Development of Arctic hydrocarbon resources has faced many challenges due to sensitive environmental conditions including low temperatures, ice cover and terrestrial permafrost and extreme seasonal variation in sunlight. Russian offshore field development in Arctic region is usually associated with annual ice cover, which can cause serious damage on the offshore platforms. The Pechora Sea has claimed as one of the most perspective oil and gas region of the Russian Arctic with seven discovered oil and gas fields and several dozens of structures. Our rough assessment, based on in-place hydrocarbon volumes and recovery factor evaluation concept, indicates that Pechora Sea alone has in-place volumes amounting to ca. 20 billion barrel oil equivalent (BOE). This quantity is enough to secure produced volumes by 2040 exceeding 3 billion BOE [1] that indicates huge resource potential of the region. The environmental conditions are primarily function of water dynamics and ice cover. The sea is covered by the ice for greatest part of the year. In this article, the ice load simulations were performed using explicit dynamic analysis system in ANSYS software to determine best shape and size of an offshore platform for the Pechora Sea ice conditions. Different gravity based structures (GBS) were analyzed: artificial island, hollow cylindrical and conical concrete structures and four-leg GBS. Relationships between the stress, deformations and time were analyzed and important observations from the simulation results were a basis for selecting the most preferable structures.

The Influence of Phenocrysts on Magma Degassing in Rhyolitic Systems

NASA Astrophysics Data System (ADS)

deGraffenried, R.; Larsen, J. F.; Lindoo, A. N.

2016-12-01

The kinetics of volatile exsolution and magma degassing control volcanic eruption styles, but the role of phenocrysts in the degassing process is poorly understood. The focus of this study is two series of decompression experiments examining how phenocrysts may or may not influence vesicle structures leading to permeability development and degassing in magmas with rhyolitic matrix melts. Powdered rhyolite obsidian (75 SiO2 wt. %; Mono Craters, CA) was seeded with 20 and 40 vol. % euhedral corundum crystals (350 μm) to approximate phenocrysts. Experiments were run using TZM (Ti-Zr-Mo alloy) vessels fitted with a water-cooled rapid quench top in a vertical Deltech furnace. Each run was held at 110 MPa and 900OC for 24 hours then decompressed continuously at a rate of 0.25 MPa/s to a final pressure (Pf) between 75 and 15 MPa. Permeability was measured using a bench-top permeameter constructed for the small experimental samples. Porosity was obtained from reflected light images using NIH Image J. The porosity of the samples increased from 11.0±1.7 to 73.3±3.1 vol % at Pf of 75 to 15 MPa for crystal free samples, 30.1±6.9 to 62.2±2.6 vol % at Pf of of 75 to 25 MPa for 20 vol % crystal samples, and 13.3±2.5 to 41.2±9.6 vol % at Pf of 75 to 50 MPa for 40 vol % crystal samples. The 20 vol % samples are impermeable up to at least 50 MPa Pf. The 40 vol % samples are impermeable up to 25 MPa Pf, with one sample having a measured Darcian permeability of -13.93±0.05 m2 at 25 MPa Pf. Comparatively, the crystal free samples were mostly impermeable up to 15 MPa, with one sample having a measured Darcian permeability of -14.41±0.04 m2 at 15 MPa Pf and 73.3 vol % porosity. Although preliminary, our permeable 40 vol % experiment suggests the phenocrysts help the samples develop permeability at a higher ending pressure and potentially lower porosity. Differences in the porosity curve as a function of pressure between the 20 and 40 vol % series indicate phenocrysts influence the vesicle structures in ascending magmas.

The Effects of Anthropogenic Structures on Habitat Connectivity and the Potential Spread of Non-Native Invertebrate Species in the Offshore Environment.

PubMed

Simons, Rachel D; Page, Henry M; Zaleski, Susan; Miller, Robert; Dugan, Jenifer E; Schroeder, Donna M; Doheny, Brandon

2016-01-01

Offshore structures provide habitat that could facilitate species range expansions and the introduction of non-native species into new geographic areas. Surveys of assemblages of seven offshore oil and gas platforms in the Santa Barbara Channel revealed a change in distribution of the non-native sessile invertebrate Watersipora subtorquata, a bryozoan with a planktonic larval duration (PLD) of 24 hours or less, from one platform in 2001 to four platforms in 2013. We use a three-dimensional biophysical model to assess whether larval dispersal via currents from harbors to platforms and among platforms is a plausible mechanism to explain the change in distribution of Watersipora and to predict potential spread to other platforms in the future. Hull fouling is another possible mechanism to explain the change in distribution of Watersipora. We find that larval dispersal via currents could account for the increase in distribution of Watersipora from one to four platforms and that Watersipora is unlikely to spread from these four platforms to additional platforms through larval dispersal. Our results also suggest that larvae with PLDs of 24 hours or less released from offshore platforms can attain much greater dispersal distances than larvae with PLDs of 24 hours or less released from nearshore habitat. We hypothesize that the enhanced dispersal distance of larvae released from offshore platforms is driven by a combination of the offshore hydrodynamic environment, larval behavior, and larval release above the seafloor.

Hydrogeological and Seismic Responses to Incoming Materials at the Non-Accreting Margin, Offshore the Osa Peninsula, Costa Rica

NASA Astrophysics Data System (ADS)

Harris, R. N.; Kameda, J.; Shimizu, M.; Ujiie, K.; Tsutsumi, A.; Ikehara, M.; Uno, M.; Yamaguchi, A.; Hamada, Y.; Namiki, Y.; Kimura, G.

2015-12-01

The relationship between temperature and the updip limit of seismicity has been demonstrated for accretionary margins where the incoming sediment is thick relative to basement relief (e.g., Oleskevich et al., JGR 1999). Here we show an example offshore the Osa Peninsula where this relationship does not appear to hold. At this non-accreting margin, the incoming sediment thickness is thin and the basement relief is substantial. The MW 6.4, 16 June 2002, Osa, Costa Rica earthquake occurred along the plate interface, 25 km landward of the trench at a depth of approximately 5-10 km (Arroyo et al., G3, 2014). Two-dimensional thermal models indicate that the temperature at this position is approximately 70-90° C (Harris et al., G3, 2010), and is cooler than the reported correlation between temperature and the updip limit of seismicity. We estimate the incoming fluid budget based on the 100 m section from the Costa Rica Seismogenesis Project reference site (IODP Exp. 334 Site U1381) using porosity and bulk mineral assemblage based on X-ray diffraction analysis of core samples. The porosity (76%) combined with the water content in smectite (~40 vol.%) and biogenic silica (~24 vol.%), leads to a total sedimentary water influx estimate of 6.9 m3/yr per m of trench length. The dehydration source term is calculated with respect to silica diagenesis and clay diagenesis using the thermal model. Peak mineral dehydration occurs at temperatures of approximately ~100 °C, 40-30 km landward of the trench and 5-10 km landward of the shallowest seismicity (Arroyo et al., G3, 2014). These results suggest that in this region the presence of subducting bathymetric relief may be more important in influencing the updip extent of seismicity than the thermal regime. This interpretation is consistent with the observed patchy seismicity (Bilek et al. Geology, 2003) and emphasizes the importance of frictional heterogeneities along the subduction thrust (Bilek and Lay, GRL, 2002).

Offshore Wind Energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strach-Sonsalla, Mareike; Stammler, Matthias; Wenske, Jan

In 1991, the Vindeby Offshore Wind Farm, the first offshore wind farm in the world, started feeding electricity to the grid off the coast of Lolland, Denmark. Since then, offshore wind energy has developed from this early experiment to a multibillion dollar market and an important pillar of worldwide renewable energy production. Unit sizes grew from 450 kW at Vindeby to the 7.5 MW-class offshore wind turbines (OWT ) that are currently (by October 2014) in the prototyping phase. This chapter gives an overview of the state of the art in offshore wind turbine (OWT) technology and introduces the principlesmore » of modeling and simulating an OWT. The OWT components -- including the rotor, nacelle, support structure, control system, and power electronics -- are introduced, and current technological challenges are presented. The OWT system dynamics and the environment (wind and ocean waves) are described from the perspective of OWT modelers and designers. Finally, an outlook on future technology is provided. The descriptions in this chapter are focused on a single OWT -- more precisely, a horizontal-axis wind turbine -- as a dynamic system. Offshore wind farms and wind farm effects are not described in detail in this chapter, but an introduction and further references are given.« less

OC5 Project Phase Ib: Validation of hydrodynamic loading on a fixed, flexible cylinder for offshore wind applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, Amy N.; Wendt, Fabian; Jonkman, Jason M.

This paper summarizes the findings from Phase Ib of the Offshore Code Comparison, Collaboration, Continued with Correlation (OC5) project. OC5 is a project run under the International Energy Agency (IEA) Wind Research Task 30, and is focused on validating the tools used for modelling offshore wind systems through the comparison of simulated responses of select offshore wind systems (and components) to physical test data. For Phase Ib of the project, simulated hydrodynamic loads on a flexible cylinder fixed to a sloped bed were validated against test measurements made in the shallow water basin at the Danish Hydraulic Institute (DHI) withmore » support from the Technical University of Denmark (DTU). The first phase of OC5 examined two simple cylinder structures (Phase Ia and Ib) to focus on validation of hydrodynamic models used in the various tools before moving on to more complex offshore wind systems and the associated coupled physics. As a result, verification and validation activities such as these lead to improvement of offshore wind modelling tools, which will enable the development of more innovative and cost-effective offshore wind designs.« less

OC5 Project Phase Ib: Validation of hydrodynamic loading on a fixed, flexible cylinder for offshore wind applications

DOE PAGES

Robertson, Amy N.; Wendt, Fabian; Jonkman, Jason M.; ...

2016-10-13

This paper summarizes the findings from Phase Ib of the Offshore Code Comparison, Collaboration, Continued with Correlation (OC5) project. OC5 is a project run under the International Energy Agency (IEA) Wind Research Task 30, and is focused on validating the tools used for modelling offshore wind systems through the comparison of simulated responses of select offshore wind systems (and components) to physical test data. For Phase Ib of the project, simulated hydrodynamic loads on a flexible cylinder fixed to a sloped bed were validated against test measurements made in the shallow water basin at the Danish Hydraulic Institute (DHI) withmore » support from the Technical University of Denmark (DTU). The first phase of OC5 examined two simple cylinder structures (Phase Ia and Ib) to focus on validation of hydrodynamic models used in the various tools before moving on to more complex offshore wind systems and the associated coupled physics. As a result, verification and validation activities such as these lead to improvement of offshore wind modelling tools, which will enable the development of more innovative and cost-effective offshore wind designs.« less

Offshore rectenna feasbility

NASA Technical Reports Server (NTRS)

Freeman, J. W.; Hervey, D.; Glaser, P.

1980-01-01

A preliminary study of the feasibility and cost of an offshore rectenna to serve the upper metropolitan east coast was performed. A candidate site at which to build a 5 GW rectenna was selected on the basis of proximity to load centers, avoidance of shipping lanes, sea floor terrain, and relocated conditions. Several types of support structures were selected for study based initially on the reference system rectenna concept of a wire mesh ground screen and dipoles each with its own rectifier and filter circuits. Possible secondary uses of an offshore rectenna were examined and are evaluated.

Pile Driving

NASA Technical Reports Server (NTRS)

1987-01-01

Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

Development of High Heat Input Welding Offshore Steel as Normalized Condition

NASA Astrophysics Data System (ADS)

Deng, Wei; Qin, Xiaomei

The heavy plate used for offshore structure is one of the important strategic products. In recent years, there is an increasing demand for heavy shipbuilding steel plate with excellent weldability in high heat input welding. During the thermal cycle, the microstructure of the heat affected zone (HAZ) of plates was damaged, and this markedly reduced toughness of HAZ. So, how to improve the toughness of HAZ has been a key subject in the fields of steel research. Oxide metallurgy is considered as an effective way to improve toughness of HAZ, because it could be used to retard grain growth by fine particles, which are stable at the high temperature.The high strength steel plate, which satisfies the low temperature specification, has been applied to offshore structure. Excellent properties of the plates and welded joints were obtained by oxide metallurgy technology, latest controlled rolling and accelerated cooling technology using Ultra-Fast Cooling (an on-line accelerated cooling system). The 355MPa-grade high strength steel plates with normalizing condition were obtained, and the steels have excellent weldability with heat input energy of 79 287kJ/cm, and the nil ductility transition (NDT) temperature was -70°C, which can satisfy the construction of offshore structure in cold regions.

Structure and magnetic properties of Ni-poly(p-xylylene) nanocomposites synthesized by vapor deposition polymerization

NASA Astrophysics Data System (ADS)

Ozerin, Sergei A.; Vdovichenko, Artem Yu.; Streltsov, Dmitry R.; Davydov, Alexander B.; Orekhov, Anton S.; Vasiliev, Alexander L.; Zubavichus, Yan V.; Grigoriev, Evgenii I.; Zavyalov, Sergei A.; Oveshnikov, Leonid N.; Aronzon, Boris A.; Chvalun, Sergei N.

2017-12-01

The relationship between structure, electrical and magnetic properties of thin poly(p-xylylene) - nickel nanocomposite films with Ni concentrations from 5 to 30 vol% was studied. It was found that metal concentration strongly affects size and oxidation state of the nanoparticles and composites morphology. At nickel concentration below 5 vol% the nanoparticles are oxidized to NiO and homogeneously distributed within fine-grained polymer matrix. An increase of Ni concentration up to 10 vol% results in the development of coarse-grained morphology with preferable localization of the nanoparticles at the boundaries of polymeric grains. And finally, in the composite films with nickel concentration above 20 vol%, the fine-grained morphology is observed again, but the nanoparticles are mainly metallic. Effect of the filler content on electrical and magnetic properties of the nanocomposites was elucidated showing that they are determined by percolation phenomenon with the threshold value of about 10 vol%. The well-pronounced magnetic hysteresis as well as ferromagnetic ordering were observed at Ni content above the percolation threshold. The diagrams of magnetic properties of these composites as a function of composition and temperature were elaborated. It was demonstrated that film annealing can be used to control magnetic properties of the composites and strongly enhance magnetoresistance.

Drivers of coastal bacterioplankton community diversity and structure along a nutrient gradient in the East China Sea

NASA Astrophysics Data System (ADS)

He, Jiaying; Wang, Kai; Xiong, Jinbo; Guo, Annan; Zhang, Demin; Fei, Yuejun; Ye, Xiansen

2017-04-01

Anthropogenic nutrient discharge poses widespread threats to coastal ecosystems and has increased environmental gradients from coast to sea. Bacterioplankton play crucial roles in coastal biogeochemical cycling, and a variety of factors affect bacterial community diversity and structure. We used 16S rRNA gene pyrosequencing to investigate the spatial variation in bacterial community composition (BCC) across five sites on a coast-offshore gradient in the East China Sea. Overall, bacterial alpha-diversity did not differ across sites, except that richness and phylogenetic diversity were lower in the offshore sites, and the highest alpha-diversity was found in the most landward site, with Chl-a being the main factor. BCCs generally clustered into coastal and offshore groups. Chl-a explained 12.3% of the variation in BCCs, more than that explained by either the physicochemical (5.7%) or spatial (8.5%) variables. Nutrients (particularly nitrate and phosphate), along with phytoplankton abundance, were more important than other physicochemical factors, co-explaining 20.0% of the variation in BCCs. Additionally, a series of discriminant families (primarily affiliated with Gammaproteobacteria and Alphaproteobacteria), whose relative abundances correlated with Chl-a, DIN, and phosphate concentrations, were identified, implying their potential to indicate phytoplankton blooms and nutrient enrichment in this marine ecosystem. This study provides insight into bacterioplankton response patterns along a coast-offshore gradient, with phytoplankton abundance increasing in the offshore sites. Time-series sampling across multiple transects should be performed to determine the seasonal and spatial patterns in bacterial diversity and community structure along this gradient.

Drivers of coastal bacterioplankton community diversity and structure along a nutrient gradient in the East China Sea

NASA Astrophysics Data System (ADS)

He, Jiaying; Wang, Kai; Xiong, Jinbo; Guo, Annan; Zhang, Demin; Fei, Yuejun; Ye, Xiansen

2018-03-01

Anthropogenic nutrient discharge poses widespread threats to coastal ecosystems and has increased environmental gradients from coast to sea. Bacterioplankton play crucial roles in coastal biogeochemical cycling, and a variety of factors affect bacterial community diversity and structure. We used 16S rRNA gene pyrosequencing to investigate the spatial variation in bacterial community composition (BCC) across five sites on a coast-offshore gradient in the East China Sea. Overall, bacterial alpha-diversity did not differ across sites, except that richness and phylogenetic diversity were lower in the offshore sites, and the highest alpha-diversity was found in the most landward site, with Chl-a being the main factor. BCCs generally clustered into coastal and offshore groups. Chl-a explained 12.3% of the variation in BCCs, more than that explained by either the physicochemical (5.7%) or spatial (8.5%) variables. Nutrients (particularly nitrate and phosphate), along with phytoplankton abundance, were more important than other physicochemical factors, co-explaining 20.0% of the variation in BCCs. Additionally, a series of discriminant families (primarily affiliated with Gammaproteobacteria and Alphaproteobacteria), whose relative abundances correlated with Chl-a, DIN, and phosphate concentrations, were identified, implying their potential to indicate phytoplankton blooms and nutrient enrichment in this marine ecosystem. This study provides insight into bacterioplankton response patterns along a coast-offshore gradient, with phytoplankton abundance increasing in the offshore sites. Time-series sampling across multiple transects should be performed to determine the seasonal and spatial patterns in bacterial diversity and community structure along this gradient.

Resolving plate structure across the seismogenic zone in Cascadia from onshore-offshore receiver function imaging

NASA Astrophysics Data System (ADS)

Audet, P.; Schaeffer, A. J.

2017-12-01

Studies of the forearc structure in the Cascadia subduction zone using teleseismic P-wave receiver function have resolved structures associated with deep fluid cycling, such as the basalt-to-eclogite reaction and fluid overpressure within the subducting oceanic crust, as well as the serpentinization of the forearc mantle wedge. Unfortunately, the updip extent of the over-pressured zone, and therefore the possible control on the transition from episodic slow slip to seismic slip, occurs offshore and is not resolved in those studies. The Cascadia Initiative (CI) has provided an opportunity to extend this work to the locked zone using teleseismic receiver functions from the deployment of a dense line of ocean-bottom seismograph stations offshore of Washington State, from the trench to the coastline. Here we calculate P-wave receiver functions using data from offshore (CI) and onshore (CAFE) broadband seismic stations. These data clearly show the various scattered phases associated with a dipping low-velocity layer that was identified in previous studies as the downgoing oceanic crust. These signals are difficult to untangle offshore because they arrive at similar times. We process receiver functions using a modified common-conversion point (CCP) stacking technique that uses a coherency filter to optimally stack images obtained from the three main scattered phases. The resulting image shows along-dip variations in the character of the seismic discontinuities associated with the top and bottom of the low-velocity layer. Combined with focal depth information of regular and low-frequency earthquakes, these variations may reflect changes in the material properties of the megathrust across the seismogenic zone in Cascadia.

Amy Robertson | NREL

Science.gov Websites

validation, and data analysis. At NREL, Amy specializes in the modeling of offshore wind system dynamics. She Amy.Robertson@nrel.gov | 303-384-7157 Amy's expertise is in structural dynamics modeling, verification and of offshore wind modeling tools. Prior to joining NREL, Amy worked as an independent consultant for

Prediction of dynamic strains on a monopile offshore wind turbine using virtual sensors

NASA Astrophysics Data System (ADS)

Iliopoulos, A. N.; Weijtjens, W.; Van Hemelrijck, D.; Devriendt, C.

2015-07-01

The monitoring of the condition of the offshore wind turbine during its operational states offers the possibility of performing accurate assessments of the remaining life-time as well as supporting maintenance decisions during its entire life. The efficacy of structural monitoring in the case of the offshore wind turbine, though, is undermined by the practical limitations connected to the measurement system in terms of cost, weight and feasibility of sensor mounting (e.g. at muddline level 30m below the water level). This limitation is overcome by reconstructing the full-field response of the structure based on the limited number of measured accelerations and a calibrated Finite Element Model of the system. A modal decomposition and expansion approach is used for reconstructing the responses at all degrees of freedom of the finite element model. The paper will demonstrate the possibility to predict dynamic strains from acceleration measurements based on the aforementioned methodology. These virtual dynamic strains will then be evaluated and validated based on actual strain measurements obtained from a monitoring campaign on an offshore Vestas V90 3 MW wind turbine on a monopile foundation.

Aeroacoustics of Flight Vehicles: Theory and Practice. Volume 1. Noise Sources

DTIC Science & Technology

1991-08-01

243. 62 Brown, Garry L.; and Roshko, Anatol On Density Effects and Large Structure in Turbulent Mixing Layers J. Fluid Aeci, vol 64, pt 4, July 24, 1974...Structure in Jet Turbulence. J. Fluid Mech., vol. 48, pt. 3, Aug. 16, 1971, pp. 547-591. 2 Brown, Garry L., and Roshko, Anatol On Density Effects and Large...depending on such things as engine power setting and combustor and turbine design considerations. The dominant frequencies associated with both combustion

Complete Genome Sequence of Rothia mucilaginosa DY-18: A Clinical Isolate with Dense Meshwork-Like Structures from a Persistent Apical Periodontitis Lesion

DTIC Science & Technology

2010-09-25

dermatitis associated with Rothia mucilaginosa bacteremia: a case report ,”American Journal of Dermatopathol- ogy, vol. 32, no. 2, pp. 175–179, 2010. [5] P...root- filled teeth with chronic apical periodontitis ,” International Endodontic Journal, vol. 34, no. 6, pp. 429–434, 2001. [12] L. C. de Paz...of Rothiamucilaginosa DY-18: A Clinical Isolate with DenseMeshwork-Like Structures from a Persistent Apical Periodontitis Lesion Kazuyoshi Yamane,1

An Empirical Examination of Reverse Auction Appropriateness in B2B Source Selection

DTIC Science & Technology

2006-01-01

Measures of Marketing Constructs," Journal of Marketing Research , Vol. 16, No.2, pp. 64 - 73. Cohn, L. (2000), "B2B: The Hottest Net Bet Yet...34 Psycholgical Bulletin, Vol. 103, No.3, pp. 411-423. Armstrong, J.S. and T.S. Overton (1977), "Estimating Nonresponse Bias in Mail Surveys," Journal of Marketing ... Research , Vol.14, No.3, pp. 396-402. Bagozzi, R. (1983), "Issues in the Application of Covariance Structure Analysis: A Further Comment," Journal of

Contrast Enhancement for Thermal Acoustic Breast Cancer Imaging via Resonant Stimulation

DTIC Science & Technology

2009-03-01

structures,” Appl . Opt., vol. 39, no. 31, pp. 5872–5883, 2000. [12] D. Feng, Y. Xu, G. Ku, and L. V. Wang, “Microwave-induced thermoa- coustic tomography...image recon- struction,” Appl . Opt., vol. 39, no. 32, pp. 5971–5977, 2000. [14] G. Kossoff, E. K. Fry, and J. Jellins, “Average velocity of ultrasound...P. Stoica, and R. Wu, “Microwave imaging via adaptive beamforming methods for breast cancer detection,” J. Electro- magn. Waves Appl ., vol. 20, no. 1

Re-assessment of offshore structures using the revised HSE fatigue guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stacey, A.; Sharp, J.V.

1995-12-31

The re-assessment of existing North Sea structures is an increasingly important issue as the age of platforms increases. Over 50 from a total of approximately 180 fixed installations in the UK sector are now over 15 years old. Fatigue damage has been the main reason for repairs to North Sea structures and the risk of this continues. The fatigue guidance of the Offshore Safety Division of the Health and Safety Executive (HSE) has recently been revised and published. Fundamental changes have been made to this guidance with several new recommendations including joint classification, basic design S-N curves for welded joints,more » the thickness effect, the effects of environment and the treatment of low and high stress ranges. To quantify the effects of the new guidance on the fatigue life assessment of offshore strictures, the HSE commissioned a study which included a deep water and a shallow water fixed steel structure and a twin-pontoon semi-submersible. These structures are typical of those operating in the North Sea. These were re-assessed with respect to fatigue lives and the results compared with predictions based on the 1990 guidance. The results and general conclusions are presented in this paper.« less

Tomographic Imaging of the Cascadia Subduction Zone and Juan de Fuca Plate System: Improved Methods Eliminate Artifacts and Reveal New Structures

NASA Astrophysics Data System (ADS)

Bodmer, M.; Toomey, D. R.; Hooft, E. E. E.; Bezada, M.; Schmandt, B.; Byrnes, J. S.

2017-12-01

Amphibious studies of subduction zones promise advances in understanding links between incoming plate structure, the subducting slab, and the upper mantle beneath the slab. However, joint onshore/offshore imaging is challenging due to contrasts between continental and oceanic structure. We present P-wave teleseismic tomography results for the Cascadia subduction zone (CSZ) that utilize existing western US datasets, amphibious seismic data from the Cascadia Initiative, and tomographic algorithms that permit 3D starting models, nonlinear ray tracing, and finite frequency kernels. Relative delay times show systematic onshore/offshore trends, which we attribute to structure in the upper 50 km. Shore-crossing CSZ seismic refraction models predict relative delays >1s, with equal contributions from elevation and crustal thickness. We use synthetic data to test methods of accounting for such shallow structure. Synthetic tests using only station static terms produce margin-wide, sub-slab low-velocity artifacts. Using a more realistic a priori 3D model for the upper 50 km better reproduces known input structures. To invert the observed delays, we use data-constrained starting models of the CSZ. Our preferred models utilize regional surface wave studies to construct a starting model, directly account for elevation, and use 3D nonlinear ray tracing. We image well-documented CSZ features, including the subducted slab down to 350 km, along strike slab variations below 150 km, and deep slab fragmentation. Inclusion of offshore data improves resolution of the sub-slab mantle, where we resolve localized low-velocity anomalies near the edges of the CSZ (beneath the Klamath and Olympic mountains). Our new imaging and resolution tests indicate that previously reported margin-wide, sub-slab low-velocity asthenospheric anomalies are an imaging artifact. Offshore, we observe low-velocity anomalies beneath the Gorda plate consistent with regional deformation and broad upwelling resulting from plate stagnation. At the Juan de Fuca Ridge we observe asymmetric low-velocity anomalies consistent with dynamic upwelling. Our results agree with recent offshore tomography studies using S wave data; however, differences in the recovered relative amplitudes are likely due to anisotropy, which we are exploring.

Guided waves in a monopile of an offshore wind turbine.

PubMed

Zernov, V; Fradkin, L; Mudge, P

2011-01-01

We study the guided waves in a structure which consists of two overlapping steel plates, with the overlapping section grouted. This geometry is often encountered in support structures of large industrial offshore constructions, such as wind turbine monopiles. It has been recognized for some time that the guided wave technology offers distinctive advantages for the ultrasonic inspections and health monitoring of structures of this extent. It is demonstrated that there exist advantageous operational regimes of ultrasonic transducers guaranteeing a good inspection range, even when the structures are totally submerged in water, which is a consideration when the wind turbines are deployed off shore. Copyright © 2010 Elsevier B.V. All rights reserved.

H. David Politzer, Asymptotic Freedom, and Strong Interaction

Science.gov Websites

Possible Non-Regge Behavior of Electroproduction Structure Functions; Physical Review D, Vol. 10, Issue 5 ; 1974 Heavy Quarks and Long-lived Hadrons; Physical Review D, Vol. 12, Issue 5; 1975 Experimental take you to non-federal websites. Their policies may differ from this site. Website Policies/Important

State-of-the-Art Review on Composite Material Fatigue/Damage Tolerance.

DTIC Science & Technology

1985-12-01

Automobile Structures," Plastic Rubber Material Application, Vol. 3, No. 2, May 1978. 148. Nguyen, D.T., Arora, J.S., and Belegundu, A.D., "Design...Vanthier, D., " Kunststoff -Verstaerkung MIT Kevlar 49," [Reinforcing Plastics With "Kevlar" 49], Plastverarbeiter, Vol. 31, No. 9, September 1980. 232

Final Technical Report. DeepCwind Consortium Research Program. January 15, 2010 - March 31, 2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagher, Habib; Viselli, Anthony; Goupee, Andrew

This is the final technical report for the U.S. Department of Energy-funded program, DE-0002981: DeepCwind Consortium Research Program. The project objective was the partial validation of coupled models and optimization of materials for offshore wind structures. The United States has a great opportunity to harness an indigenous abundant renewable energy resource: offshore wind. In 2010, the National Renewable Energy Laboratory (NREL) estimated there to be over 4,000 GW of potential offshore wind energy found within 50 nautical miles of the US coastlines (Musial and Ram, 2010). The US Energy Information Administration reported the total annual US electric energy generation inmore » 2010 was 4,120 billion kilowatt-hours (equivalent to 470 GW) (US EIA, 2011), slightly more than 10% of the potential offshore wind resource. In addition, deep water offshore wind is the dominant US ocean energy resource available comprising 75% of the total assessed ocean energy resource as compared to wave and tidal resources (Musial, 2008). Through these assessments it is clear offshore wind can be a major contributor to US energy supplies. The caveat to capturing offshore wind along many parts of the US coast is deep water. Nearly 60%, or 2,450 GW, of the estimated US offshore wind resource is located in water depths of 60 m or more (Musial and Ram, 2010). At water depths over 60 m building fixed offshore wind turbine foundations, such as those found in Europe, is likely economically infeasible (Musial et al., 2006). Therefore floating wind turbine technology is seen as the best option for extracting a majority of the US offshore wind energy resource. Volume 1 - Test Site; Volume 2 - Coupled Models; and Volume 3 - Composite Materials« less

English-Spanish glossary: offshore exploration and production, gas processing, and valves (in Spanish)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-12-01

This series of articles contains 3 different English-Spanish glossaries of related terms used in the oil industry. The glossary of the offshore exploration and production involves a summary of terms used in the offshore oil activity. It also includes names of singular equipment used in offshore drilling, as well as several navigation terms in relation to the floating oil structures. With the help of the Gas Processors Association it was possible to compile a glossary of gas processing with a concise selection of common terms of the industry of gas processing. The glossary of valves includes more than 200 termsmore » of the industry of valves in a specialized glossary, and several explanations about the application and operation of valves.« less

Influence of multi-walled carbon nanotubes (MWCNTs) volume percentage on the magnetic and microwave absorbing properties of BaMg{sub 0.5}Co{sub 0.5}TiFe{sub 10}O{sub 19}/MWCNTs nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alam, Reza Shams; Moradi, Mahmood, E-mail: moradi@susc.ac.ir; Institute of Nanotechnology, Shiraz University, Shiraz 71454

2016-01-15

Graphical abstract: Reflection losses of (a) doped barium hexaferrite, BaMg{sub 0.5}Co{sub 0.5}TiFe{sub 10}O{sub 19}, sample and their nanocomposites with (b) 4 vol. (c) 8 vol. and (d) 12 vol.% of MWCNTs are presented. - Highlights: • BaMg{sub 0.5}Co{sub 0.5}TiFe{sub 10}O{sub 19}/MWCNTs nanocomposites were synthesized. • The structural, magnetic and microwave absorption properties were investigated. • The microwave absorption is strongly influenced by volume percentage of MWCNTs. • The nanocomposite with 8 vol.% of MWCNTs can be proposed as a wideband absorber. - Abstract: In this study BaMg{sub 0.5}Co{sub 0.5}TiFe{sub 10}O{sub 19}/MWCNTs nanocomposites with different amount of MWCNTs (0, 4, 8more » and 12 vol.%) were synthesized. Here, the X-ray diffraction (XRD), Fourier transform spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to demonstrate the structural and morphological characteristics of the prepared samples. XRD along with FTIR examinations exhibited that the nanocomposites were successfully synthesized. Vibrating sample magnetometer (VSM) showed the relatively strong dependence of saturation magnetization and coercivity on the volume percentage of MWCNTs. The microwave evaluation also confirmed that the complex permittivity of nanocomposites could be enhanced by adding MWCNTs. Finally, the nanocomposite with 8% vol. of MWCNTs exhibited the best microwave absorption performance among the samples.« less

Nighttime approaches to offshore installations in Brazil: Safety shortcomings experienced by helicopter pilots.

PubMed

Nascimento, Felipe A C; Majumdar, Arnab; Jarvis, Steve

2012-07-01

Accident rates for night sorties by helicopters traveling to offshore oil and gas platforms are at least five times higher than those during the daytime. Because pilots need to transition from automated flight to a manually flown night visual segment during arrival, the approach and landing phases cause great concern. Despite this, in Brazil, regulatory changes have been sought to allow for the execution of offshore night flights because of the rapid expansion of the petroleum industry. This study explores the factors that affect safety during night visual segments in Brazil using 28 semi-structured interviews with offshore helicopter pilots, followed by a template analysis of the narratives. The relationships among the factors suggest that flawed safety oversights, caused by a combination of lack of infrastructure for night flights offshore and declining training, currently favor spatial disorientation on the approach and near misses when close to the destination. Safety initiatives can be derived on the basis of these results. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genetic divergence between two phenotypically distinct bottlenose dolphin ecotypes suggests separate evolutionary trajectories.

PubMed

Fruet, Pedro F; Secchi, Eduardo R; Di Tullio, Juliana C; Simões-Lopes, Paulo César; Daura-Jorge, Fábio; Costa, Ana P B; Vermeulen, Els; Flores, Paulo A C; Genoves, Rodrigo Cezar; Laporta, Paula; Beheregaray, Luciano B; Möller, Luciana M

2017-11-01

Due to their worldwide distribution and occupancy of different types of environments, bottlenose dolphins display considerable morphological variation. Despite limited understanding about the taxonomic identity of such forms and connectivity among them at global scale, coastal (or inshore) and offshore (or oceanic) ecotypes have been widely recognized in several ocean regions. In the Southwest Atlantic Ocean (SWA), however, there are scarce records of bottlenose dolphins differing in external morphology according to habitat preferences that resemble the coastal-offshore pattern observed elsewhere. The main aim of this study was to analyze the genetic variability, and test for population structure between coastal ( n  = 127) and offshore ( n  = 45) bottlenose dolphins sampled in the SWA to assess whether their external morphological distinction is consistent with genetic differentiation. We used a combination of mtDNA control region sequences and microsatellite genotypes to infer population structure and levels of genetic diversity. Our results from both molecular marker types were congruent and revealed strong levels of structuring (microsatellites F ST  = 0.385, p  < .001; mtDNA F ST  =  0.183, p  < .001; Φ ST  = 0.385, p  < .001) and much lower genetic diversity in the coastal than the offshore ecotype, supporting patterns found in previous studies elsewhere. Despite the opportunity for gene flow in potential "contact zones", we found minimal current and historical connectivity between ecotypes, suggesting they are following discrete evolutionary trajectories. Based on our molecular findings, which seem to be consistent with morphological differentiations recently described for bottlenose dolphins in our study area, we recommend recognizing the offshore bottlenose dolphin ecotype as an additional Evolutionarily Significant Unit (ESU) in the SWA. Implications of these results for the conservation of bottlenose dolphins in SWA are also discussed.

Improved Target Detection in Urban Structures Using Distributed Sensing and Fast Data Acquisition Techniques

DTIC Science & Technology

2013-04-01

Trans. Signal Process., vol. 57, no. 6, pp. 2275-2284, 2009. [83] A. Gurbuz, J. IVIcClellan, and W. Scott, "Compressive sensing for subsurface ... imaging using ground penetrating radar," Signal Pracess., vol. 89, no. 10, pp. 1959 -1972, 2009. [84] A. Gurbuz, J. McClellan, and W. Scott, "A

Mechanical Properties of Structural Polymers. Computer Simulations and Key Experiments

DTIC Science & Technology

1992-09-30

Technology", edited by R.W. Cahn, P. Haasen, and E.J. Kramer, (VCH: Weinheim, Germany) (vol. editor H. Mughrabi ) Vol. 6, in the press (1992). 14. A.S. Argon...34, Acta Metall. et Mater., submitted for publication. 5 32. A. Galeski, Z. Bartczak, A.S. Argon and R.E. Cohen, "Morphological Al - terations during

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Bingbin; Karr, Dale G.; Song, Huimin

It is a fact that developing offshore wind energy has become more and more serious worldwide in recent years. Many of the promising offshore wind farm locations are in cold regions that may have ice cover during wintertime. The challenge of possible ice loads on offshore wind turbines raises the demand of modeling capacity of dynamic wind turbine response under the joint action of ice, wind, wave, and current. The simulation software FAST is an open source computer-aided engineering (CAE) package maintained by the National Renewable Energy Laboratory. In this paper, a new module of FAST for assessing the dynamicmore » response of offshore wind turbines subjected to ice forcing is presented. In the ice module, several models are presented which involve both prescribed forcing and coupled response. For conditions in which the ice forcing is essentially decoupled from the structural response, ice forces are established from existing models for brittle and ductile ice failure. For conditions in which the ice failure and the structural response are coupled, such as lock-in conditions, a rate-dependent ice model is described, which is developed in conjunction with a new modularization framework for FAST. In this paper, analytical ice mechanics models are presented that incorporate ice floe forcing, deformation, and failure. For lower speeds, forces slowly build until the ice strength is reached and ice fails resulting in a quasi-static condition. For intermediate speeds, the ice failure can be coupled with the structural response and resulting in coinciding periods of the ice failure and the structural response. A third regime occurs at high speeds of encounter in which brittle fracturing of the ice feature occurs in a random pattern, which results in a random vibration excitation of the structure. An example wind turbine response is simulated under ice loading of each of the presented models. This module adds to FAST the capabilities for analyzing the response of wind turbines subjected to forces resulting from ice impact on the turbine support structure. The conditions considered in this module are specifically addressed in the International Organization for Standardization (ISO) standard 19906:2010 for arctic offshore structures design consideration. Special consideration of lock-in vibrations is required due to the detrimental effects of such response with regard to fatigue and foundation/soil response. Finally, the use of FAST for transient, time domain simulation with the new ice module is well suited for such analyses.« less

Floating Offshore Wind in California: Gross Potential for Jobs and Economic Impacts from Two Future Scenarios

DOE Office of Scientific and Technical Information (OSTI.GOV)

Speer, Bethany; Keyser, David; Tegen, Suzanne

Construction of the first offshore wind farm in the United States began in 2015, using fixed platform structures that are appropriate for shallow seafloors, like those located off of the East Coast and mid-Atlantic. However, floating platforms, which have yet to be deployed commercially, will likely need to anchor to the deeper seafloor if deployed off of the West Coast. To analyze the employment and economic potential for floating offshore wind along the West Coast, the Bureau of Ocean Energy Management (BOEM) has commissioned the National Renewable Energy Laboratory (NREL) to analyze two hypothetical, large-scale deployment scenarios for California: 16more » GW of offshore wind by 2050 (Scenario A) and 10 GW of offshore wind by 2050 (Scenario B). The results of this analysis can be used to better understand the general scales of economic opportunities that could result from offshore wind development. Results show total state gross domestic product (GDP) impacts of $16.2 billion in Scenario B or $39.7 billion in Scenario A for construction; and $3.5 billion in Scenario B or $7.9 billion in Scenario A for the operations phases.« less

Taking ownership of safety. What are the active ingredients of safety coaching and how do they impact safety outcomes in critical offshore working environments?

PubMed

Krauesslar, Victoria; Avery, Rachel E; Passmore, Jonathan

2015-01-01

Safety coaching interventions have become a common feature in the safety critical offshore working environments of the North Sea. Whilst the beneficial impact of coaching as an organizational tool has been evidenced, there remains a question specifically over the use of safety coaching and its impact on behavioural change and producing safe working practices. A series of 24 semi-structured interviews were conducted with three groups of experts in the offshore industry: safety coaches, offshore managers and HSE directors. Using a thematic analysis approach, several significant themes were identified across the three expert groups including connecting with and creating safety ownership in the individual, personal significance and humanisation, ingraining safety and assessing and measuring a safety coach's competence. Results suggest clear utility of safety coaching when applied by safety coaches with appropriate coach training and understanding of safety issues in an offshore environment. The current work has found that the use of safety coaching in the safety critical offshore oil and gas industry is a powerful tool in managing and promoting a culture of safety and care.

Scenario analysis for techno-economic model development of U.S. offshore wind support structures

DOE PAGES

Damiani, Rick; Ning, Andrew; Maples, Ben; ...

2016-09-22

Challenging bathymetry and soil conditions of future US offshore wind power plants might promote the use of multimember, fixed-bottom structures (or 'jackets') in place of monopiles. Support structures affect costs associated with the balance of system and operation and maintenance. Understanding the link between these costs and the main environmental design drivers is crucial in the quest for a lower levelized cost of energy, and it is the main rationale for this work. Actual cost and engineering data are still scarce; hence, we evaluated a simplified engineering approach to tie key site and turbine parameters (e.g. water depth, wave height,more » tower-head mass, hub height and generator rating) to the overall support weight. A jacket-and-tower sizing tool, part of the National Renewable Energy Laboratory's system engineering software suite, was utilized to achieve mass-optimized support structures for 81 different configurations. This tool set provides preliminary sizing of all jacket components. Results showed reasonable agreement with the available industry data, and that the jacket mass is mainly driven by water depth, but hub height and tower-head mass become more influential at greater turbine ratings. A larger sensitivity of the structural mass to wave height and target eigenfrequency was observed for the deepest water conditions (>40 m). Thus, techno-economic analyses using this model should be based on accurate estimates of actual metocean conditions and turbine parameters especially for deep waters. Finally, the relationships derived from this study will inform National Renewable Energy Laboratory's offshore balance of system cost model, and they will be used to evaluate the impact of changes in technology on offshore wind lower levelized cost of energy.« less

Fine-scale spatial patterns in the demersal fish and invertebrate community in a northwest Atlantic ecosystem

NASA Astrophysics Data System (ADS)

Malek, Anna J.; Collie, Jeremy S.; Gartland, James

2014-06-01

The abundance, biomass, diversity, and species composition of the demersal fish and invertebrate community in Rhode Island Sound and Block Island Sound, an area identified for offshore renewable energy development, were evaluated for spatial and seasonal structure. We conducted 58 otter trawls and 51 beam trawls in the spring, summer and fall of 2009-2012, and incorporated additional data from 88 otter trawls conducted by the Northeast Area Monitoring and Assessment Program. We used regionally-grouped abundance, biomass, diversity, and size spectra to assess spatial patterns in the aggregate fish community, and hierarchical cluster analysis to evaluate trends in species assemblages. Our analyses revealed coherent gradients in fish community biomass, diversity and species composition extending from inshore to offshore waters, as well as patterns related to the differing bathymetry of Rhode Island and Block Island Sounds. The fish communities around Block Island and Cox's Ledge are particularly diverse, suggesting that the proximity of hard bottom habitat may be important in structuring fish communities in this area. Species assemblages in Rhode Island and Block Island Sounds are characterized by a combination of piscivores (silver hake, summer flounder, spiny dogfish), benthivores (American lobster, black sea bass, Leucoraja spp. skates, scup) and planktivores (sea scallop), and exhibit geographic patterns that are persistent from year to year, yet variable by season. Such distributions reflect the cross-shelf migration of fish and invertebrate species in the spring and fall, highlighting the importance of considering seasonal fish behavior when planning construction schedules for offshore development projects. The fine spatial scale (10 s of kms) of this research makes it especially valuable for local marine spatial planning efforts by identifying local-scale patterns in fish community structure that will enable future assessment of the ecological impacts of offshore development. As such, this knowledge of the spatial and temporal structure of the demersal fish community in Rhode Island and Block Island Sounds will help to guide the placement of offshore structures so as to preserve the ecological and economic value of the area.

Optimization of monopiles for offshore wind turbines.

PubMed

Kallehave, Dan; Byrne, Byron W; LeBlanc Thilsted, Christian; Mikkelsen, Kristian Kousgaard

2015-02-28

The offshore wind industry currently relies on subsidy schemes to be competitive with fossil-fuel-based energy sources. For the wind industry to survive, it is vital that costs are significantly reduced for future projects. This can be partly achieved by introducing new technologies and partly through optimization of existing technologies and design methods. One of the areas where costs can be reduced is in the support structure, where better designs, cheaper fabrication and quicker installation might all be possible. The prevailing support structure design is the monopile structure, where the simple design is well suited to mass-fabrication, and the installation approach, based on conventional impact driving, is relatively low-risk and robust for most soil conditions. The range of application of the monopile for future wind farms can be extended by using more accurate engineering design methods, specifically tailored to offshore wind industry design. This paper describes how state-of-the-art optimization approaches are applied to the design of current wind farms and monopile support structures and identifies the main drivers where more accurate engineering methods could impact on a next generation of highly optimized monopiles. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

The electrical resistivity and percolation threshold of MWCNTs/polymer composites filled with a few aligned carbonyl iron particles

NASA Astrophysics Data System (ADS)

Dong, Shuai; Wang, Xiaojie

2018-03-01

Conductive polymer composites (CPCs) consist of multi-walled carbon nanotubes (MWCNTs), a few carbonyl iron particles (CIPs) and polydimethylsiloxane (PDMS) are fabricated under a moderate magnetic field. The alignment of CIPs will change the structure of MWCNT network, and consequently the electrical properties of CPCs. The volume fraction of CIPs is fixed at 0.08 vol% at which CIPs will not directly participate in electric conduction. The electrical resistivity of CPCs and the changes of resistance versus strain are evaluated at various MWCNT volume fractions. The testing results show that a percolation threshold as low as 0.19 vol% is obtained due to the effect of aligned CIPs, comparing with 0.39 vol% of isotropic MWCNT/CIP/PDMS (prepared without magnetic field). Meanwhile, the anisotropic structure reduces the electrical resistivity by more than 80% when the MWCNT volume fractions is over the percolation threshold.

Simulated Microstructure-Sensitive Extreme Value Probabilities for High Cycle Fatigue of Duplex Ti-6Al-4V

DTIC Science & Technology

2010-04-01

of texture on  mechanical   properties  in an advanced  titanium  alloy,"  Materials Science and Engineering A, vol. 319‐321, pp. 409‐414, 2001.  Simulated... mechanisms  of fatigue facet nucleation in  titanium  alloys," Fatigue  and Fracture of Engineering Materials and  Structures , vol. 31, pp. 949‐958, 2008...crack initiation in Ti‐6Al‐4V  titanium   alloy," Fatigue and Fracture of Engineering Materials and  Structures , vol. 25, pp. 527‐545, 2002.  [20]  I

Offshore platform structure intended to be installed in arctic waters, subjected to drifting icebergs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kure, G.; Jenssen, D.N.; Naesje, K.

1984-09-11

An offshore platform structure, particularly intended to be installed in waters where drifting iceberg frequently appear, the platform structure being intended to be founded in a sea bed and comprises a substructure, a superstructure rigidly affixed to the substructure and extending vertically up above the sea level supporting a deck superstructure at its upper end. The horizontal cross-sectional area of the substructure is substantially greater than tath of the superstructure. The substructure rigidly supports a fender structure, the fender structure comprising an outer peripherally arranged wall and an inner cylindrical wall the inner and outer wall being rigidly interconnected bymore » means of a plurality of vertical and/or horizontal partition walls, dividing the fender structure into a plurality of cells or compartlents. The fender structure is arranged in spaced relation with respect to the superstructure.« less

Floating Offshore Wind in Oregon: Potential for Jobs and Economic Impacts from Two Future Scenarios

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jimenez, Tony; Keyser, David; Tegen, Suzanne

Construction of the first offshore wind power plant in the United States began in 2015, off the coast of Rhode Island, using fixed platform structures that are appropriate for shallow seafloors, like those located off of the East Coast and mid-Atlantic. However, floating platforms, which have yet to be deployed commercially, will likely need to anchor to the deeper seafloor if deployed off of the West Coast. To analyze the employment and economic potential for floating offshore wind along the West Coast, the Bureau of Ocean Energy Management (BOEM) commissioned the National Renewable Energy Laboratory (NREL) to analyze two hypothetical,more » large-scale deployment scenarios for Oregon: 5,500 megawatts (MW) of offshore wind deployment in Oregon by 2050 (Scenario A), and 2,900 MW of offshore wind by 2050 (Scenario B). These levels of deployment could power approximately 1,600,000 homes (Scenario A) or 870,000 homes (Scenario B). Offshore wind would contribute to economic development in Oregon in the near future, and more substantially in the long term, especially if equipment and labor are sourced from within the state. According to the analysis, over the 2020-2050 period, Oregon floating offshore wind facilities could support 65,000-97,000 job-years and add $6.8 billion-$9.9 billion to the state GDP (Scenario A).« less

Offshore Windfarm Impact on Pelagic Primary Production in the Southern North Sea

NASA Astrophysics Data System (ADS)

Slavik, Kaela; Zhang, Wenyan; Lemmen, Carsten; Wirtz, Kai

2016-04-01

As society struggles to find solutions to mitigate global warming, the demand for renewable energy technology has increased. Especially investment in offshore wind energy has proliferated in the European Union, with projections over the next 15 years estimating an over 40 fold increase in total offshore wind electricity. Though built with the goal of reducing the environmental impacts associated with traditional energy production, the long-term ecological impacts of offshore windfarm structures is not yet well understood. The consequences are of particular importance in the southern North Sea, where the expansion of offshore windfarms is focused. Our study investigates how the gradual accumulation of epifaunal biomass on submerged substrate at offshore windfarms impacts ecosystem services in the southern North Sea. Biofouling is governed predominately by the filter feeder Mytilus edulis, which, as an ecological engineer, will further alter the surrounding benthic and pelagic environment. We reconstruct the distribution of benthic filter feeders in the SNS and generate scenarios of increased potential distribution based on available information of Mytilus edulis settlement at turbines and of turbine locations. These maps are coupled through the MOSSCO (Modular Coupling System for Shelves and Coasts) to state-of-the-art and high resolution hydrodynamic and ecosystem models. We find a substantial change in pelagic primary production as a result of additional Mytilus edulis growth at offshore windfarms.

The limits of seaward spreading and slope instability at the continental margin offshore Mt Etna, imaged by high-resolution 2D seismic data

NASA Astrophysics Data System (ADS)

Gross, Felix; Krastel, Sebastian; Geersen, Jacob; Behrmann, Jan Hinrich; Ridente, Domenico; Chiocci, Francesco Latino; Bialas, Jörg; Papenberg, Cord; Cukur, Deniz; Urlaub, Morelia; Micallef, Aaron

2016-01-01

Mount Etna is the largest active volcano in Europe. Instability of its eastern flank is well documented onshore, and continuously monitored by geodetic and InSAR measurements. Little is known, however, about the offshore extension of the eastern volcano flank, defining a serious shortcoming in stability models. In order to better constrain the active tectonics of the continental margin offshore the eastern flank of the volcano, we acquired a new high-resolution 2D reflection seismic dataset. The data provide new insights into the heterogeneous geology and tectonics at the continental margin offshore Mt Etna. The submarine realm is characterized by different blocks, which are controlled by local- and regional tectonics. A compressional regime is found at the toe of the continental margin, which is bound to a complex basin system. Both, the clear link between on- and offshore tectonic structures as well as the compressional regime at the easternmost flank edge, indicate a continental margin gravitational collapse as well as spreading to be present at Mt Etna. Moreover, we find evidence for the offshore southern boundary of the moving flank, which is identified as a right lateral oblique fault north of Catania Canyon. Our findings suggest a coupled volcano edifice/continental margin instability at Mt Etna, demonstrating first order linkage between on- and offshore tectonic processes.

Friction Stir Welding of Line-Pipe Steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanderson, Samuel; Mahoney, Murray; Feng, Zhili

Friction stir welding (FSW) offers both economic and technical advantages over conventional fusion welding practices for welding line-pipe. For offshore line-pipe construction, the economic savings has been shown to be considerable, approaching a calculated 25%. Offshore pipe is relatively small diameter but heavy wall compared to onshore pipe. One concern is the ability to achieve consistent full weld penetration in an on-site offshore FSW operation, e.g., on a lay-barge. In addition, depending on the size and morphology of the unwelded zone, lack of penetration at the weld root can be difficult if not impossible to detect by conventional NDE methods.more » Thus, an approach to assure consistent full penetration via process control is required for offshore line-pipe construction using FSW. For offshore construction, an internal structural mandrel can be used offering the opportunity to use a sacrificial anvil FSW approach. With this approach, a small volume of sacrificial material can be inserted into the structural anvil. The FSW tool penetrates into the sacrificial anvil, beyond the inner diameter of the pipe wall, thus assuring full penetration. The sacrificial material is subsequently removed from the pipe inner wall. In the work presented herein, FSW studies were completed on both 6 mm and 12 mm wall thickness line-pipe. Lastly, post-FSW evaluations including radiography, root-bend tests, and metallography demonstrated the merits of the sacrificial anvil approach to achieve consistent full penetration.« less

Introduction to “Global tsunami science: Past and future, Volume II”

USGS Publications Warehouse

Rabinovich, Alexander B.; Fritz, Hermann M.; Tanioka, Yuichiro; Geist, Eric L.

2017-01-01

Twenty-two papers on the study of tsunamis are included in Volume II of the PAGEOPH topical issue “Global Tsunami Science: Past and Future”. Volume I of this topical issue was published as PAGEOPH, vol. 173, No. 12, 2016 (Eds., E. L. Geist, H. M. Fritz, A. B. Rabinovich, and Y. Tanioka). Three papers in Volume II focus on details of the 2011 and 2016 tsunami-generating earthquakes offshore of Tohoku, Japan. The next six papers describe important case studies and observations of recent and historical events. Four papers related to tsunami hazard assessment are followed by three papers on tsunami hydrodynamics and numerical modelling. Three papers discuss problems of tsunami warning and real-time forecasting. The final set of three papers importantly investigates tsunamis generated by non-seismic sources: volcanic explosions, landslides, and meteorological disturbances. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

Introduction to "Global Tsunami Science: Past and Future, Volume II"

NASA Astrophysics Data System (ADS)

Rabinovich, Alexander B.; Fritz, Hermann M.; Tanioka, Yuichiro; Geist, Eric L.

2017-08-01

Twenty-two papers on the study of tsunamis are included in Volume II of the PAGEOPH topical issue "Global Tsunami Science: Past and Future". Volume I of this topical issue was published as PAGEOPH, vol. 173, No. 12, 2016 (Eds., E. L. Geist, H. M. Fritz, A. B. Rabinovich, and Y. Tanioka). Three papers in Volume II focus on details of the 2011 and 2016 tsunami-generating earthquakes offshore of Tohoku, Japan. The next six papers describe important case studies and observations of recent and historical events. Four papers related to tsunami hazard assessment are followed by three papers on tsunami hydrodynamics and numerical modelling. Three papers discuss problems of tsunami warning and real-time forecasting. The final set of three papers importantly investigates tsunamis generated by non-seismic sources: volcanic explosions, landslides, and meteorological disturbances. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

Interventions for confusion and dementia. 5: Changing cultures.

PubMed

Woodrow, P

Previous articles in this series (Vol 7(15): 891-94; Vol 7(17): 1018-20; Vol 7(19): 1145-49; Vol 7(20): 1247-50) have explored the promotion of quality of life for people with dementia and how this can be achieved through existing interventions. This final article moves from discussing specific interventions to cover wider issues around healthcare beliefs and values. A brief historical overview of dementia care is given, outlining the inherited structures and values. Much valuable work has been carried out by the Bradford Dementia Group, who has described changes in dementia care as moving from an 'old' to a 'new' culture. This 'new culture', offering a comprehensive person-centred approach to holistic care, is explored with reference to the work of Kitwood, who has done much to promote quality of life for people suffering from dementia.

Magnetic mapping for structural geology and geothermal exploration in Guadeloupe, Lesser Antilles

NASA Astrophysics Data System (ADS)

Mercier de Lépinay, jeanne; munschy, marc; geraud, yves; diraison, marc; navelot, vivien; verati, christelle; corsini, michel; lardeaux, jean marc; favier, alexiane

2017-04-01

This work is implemented through the GEOTREF program which benefits from the support of both the ADEME and the French public funds "Investments for the future". The program focuses on the exploration for geothermal resources in Guadeloupe, Lesser Antilles, where a geothermal power plant is in production since 1986 (Bouillante, Basse Terre). In Les Saintes archipelago, in the south of Guadeloupe, the outcrop analysis of Terre-de-Haut Island allows to point out an exhumed geothermal paleo-system that is thought to be an analogue of the Bouillante active geothermal system. We show that a detailed marine magnetic survey with a quantitative interpretation can bring information about the offshore structures around Les Saintes archipelago in order to extend the geological limits and structural elements. A similar survey and workflow is also conducted offshore Basse-Terre where more geophysical data is already available. In order to correctly link the offshore and onshore structures, the magnetic survey must be close enough to the shoreline and sufficiently detailed to correctly outline the tectonic structures. An appropriate solution for such a survey is to use a three component magnetometer aboard a speedboat. Such a boat allows more navigation flexibility than a classic oceanic vessel towing a magnetometer; it can sail at higher speed on calm seas and closer to the shoreline. This kind of magnetic acquisition is only viable because the magnetic effect of the ship can be compensated using the same algorithms than those used for airborne magnetometry. The use of potential field transforms allows a large variety of structures to be highlighted, providing insights to build a general understanding of the nature and distribution of the magnetic sources. In particular, we use the tilt angle operator to better identify the magnetic lineaments offshore in order to compare them to the faults identified onshore during the outcrop analysis. All the major faults and fractures directions observed onshore are well represented through the magnetic lineaments except the main N90-110 system which is almost inexistent. We also invert the magnetic data to obtain a magnetization intensity map. This inversion assumes a constant depth magnetized layer and a constant magnetization's direction. The calculated variations on the map are consistent with on-field measurements showing that hydrothermalized rocks have a lower magnetic susceptibility (2 orders of magnitude) than fresh ones. Our interpretation and the onshore structural and petrographic analysis allow us to recognize the offshore extension of the hydrothermalized area, as well as different structural orientations.

Work, eat and sleep: towards a healthy ageing at work program offshore.

PubMed

Riethmeister, Vanessa; Brouwer, Sandra; van der Klink, Jac; Bültmann, Ute

2016-02-09

Health management tools need to be developed to foster healthy ageing at work and sustain employability of ageing work-forces. The objectives of this study were to 1) perform a needs assessment to identify the needs of offshore workers in the Dutch Continental Shelf with regard to healthy ageing at work and 2) to define suitable program objectives for a future healthy ageing at work program in the offshore working population. A mixed methods design was used applying an intervention mapping procedure. Qualitative data were gathered in N = 19 semi-structured interviews and six focus-group sessions (N = 49). Qualitative data were used to develop a questionnaire, which was administered among N = 450 offshore workers. Subgroup analyses were performed to investigate age-related differences relating to health status and work-related factors. The importance of good working environments, food, as well as sleep/fatigue management was identified by the qualitative data analysis. A total of 260 offshore workers completed the questionnaire. Significant differences in work ability were found between offshore workers aged <45 and 45-54 years (mean 8.63 vs. 8.19; p = 0.005) and offshore workers aged <45 and >55 years (mean 8.63 vs. 8.22; p = 0.028). Offshore workers had a high BMI (M = 27.06, SD = 3.67), with 46 % classified as overweight (BMI 25-30) and 21 % classified as obese (BMI >30). A significant difference in BMI was found between offshore workers aged <45 and ≥55 years (mean 26.3 vs. 28.6; p <0.001). In total, 73 % of offshore workers reported prolonged fatigue. A significant difference in fatigue scores was found between offshore workers aged <45 and ≥55 years (mean 36.0 vs. 37.6; p = 0.024). Further, a "dip" was reported by 41 % of offshore workers. Dips were mainly experienced at day 10 or 11 (60 %), with 45 % experiencing the dip both as physical and mental fatigue, whereas 39 % experienced the dip as only mental fatigue. Both qualitative and quantitative analyses identified work, food and sleep/fatigue management as most important program objectives for a healthy ageing at work and sustainable employability program offshore. Future studies should investigate possible causes of dip occurrences and high fatigue scores to identify suitable interventions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cornaggia, F.; Congo, S.A.; Agostino, M.

Kitina field is located in Marine VII permit, offshore Congo. The field was discovered in 1991 by a joint venture composed of Agip Recherches Congo (operator), Hydrocongo and Chevron International Limited. The field is a structural four-way dip closure trap shaped as turtle-back. Halokinetic movements are responsible for the structuring. The seismic imaging of the reservoir is affected by strong lateral velocity variations caused by different sedimentation across the paleo-shelf edge in the post-Albian sequence. One pass 3D poststack depth migration, performed with a velocity field obtained by means of geostatistical integration of 2D seismic and wellbore velocities, achieved amore » good compromise between high dip reflector imaging and depths at well location. Three main reservoirs of lower Albian age exist between -2100 and -3100m. They are separated by tight mudstones which act as intraformational seal. Seismic trace inversion improved the resolution of petrophysical variations in some of the field reservoirs, which have the following characteristics (from top to bottom): reservoir 2A is composed of bioclastic and oolitic packstone-grainstone laid down during regional regressive phase in insulated offshore bars on the crest of structural high. Early diagenetic phenomena lead to the development of world class permeability framework. Reservoir 1A-1B are composed of sandstone bodies which were deposited as shoreface to offshore bars during short-term regressive pulse. The 1A-1B reservoir, are embedded in mudstones deposited during long lasting phases of relative high stand in relatively deep offshore setting characterised by high, halokinetic driven subsidence.« less

Assessing Fatigue and Ultimate Load Uncertainty in Floating Offshore Wind Turbines Due to Varying Simulation Length

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, G.; Lackner, M.; Haid, L.

2013-07-01

With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation lengthmore » on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.« less

3D Modelling of Seismically Active Parts of Underground Faults via Seismic Data Mining

NASA Astrophysics Data System (ADS)

Frantzeskakis, Theofanis; Konstantaras, Anthony

2015-04-01

During the last few years rapid steps have been taken towards drilling for oil in the western Mediterranean sea. Since most of the countries in the region benefit mainly from tourism and considering that the Mediterranean is a closed sea only replenishing its water once every ninety years careful measures are being taken to ensure safe drilling. In that concept this research work attempts to derive a three dimensional model of the seismically active parts of the underlying underground faults in areas of petroleum interest. For that purpose seismic spatio-temporal clustering has been applied to seismic data to identify potential distinct seismic regions in the area of interest. Results have been coalesced with two dimensional maps of underground faults from past surveys and seismic epicentres, having followed careful reallocation processing, have been used to provide information regarding the vertical extent of multiple underground faults in the region of interest. The end product is a three dimensional map of the possible underground location and extent of the seismically active parts of underground faults. Indexing terms: underground faults modelling, seismic data mining, 3D visualisation, active seismic source mapping, seismic hazard evaluation, dangerous phenomena modelling Acknowledgment This research work is supported by the ESPA Operational Programme, Education and Life Long Learning, Students Practical Placement Initiative. References [1] Alves, T.M., Kokinou, E. and Zodiatis, G.: 'A three-step model to assess shoreline and offshore susceptibility to oil spills: The South Aegean (Crete) as an analogue for confined marine basins', Marine Pollution Bulletin, In Press, 2014 [2] Ciappa, A., Costabile, S.: 'Oil spill hazard assessment using a reverse trajectory method for the Egadi marine protected area (Central Mediterranean Sea)', Marine Pollution Bulletin, vol. 84 (1-2), pp. 44-55, 2014 [3] Ganas, A., Karastathis, V., Moshou, A., Valkaniotis, S., Mouzakiotis, E. and Papathanassiou, G.: 'Aftershock relocation and frequency-size distribution, stress inversion and seismotectonic setting of the 7 August 2013 M=5.4 earthquake in Kallidromon Mountain, central Greece', Tectonophysics, vol. 617, pp. 101-113, 2014 [4] Maravelakis, E., Bilalis, N., Mantzorou, I., Konstantaras, A. and Antoniadis, A.: '3D modelling of the oldest olive tree of the world', International Journal Of Computational Engineering Research, vol. 2 (2), pp. 340-347, 2012 [5] Konstantaras, A., Katsifarakis, E, Maravelakis, E, Skounakis, E, Kokkinos, E. and Karapidakis, E.: 'Intelligent spatial-clustering of seismicity in the vicinity of the Hellenic seismic arc', Earth Science Research, vol. 1 (2), pp. 1- 10, 2012 [6] Georgoulas, G., Konstantaras, A., Katsifarakis, E., Stylios, C., Maravelakis, E and Vachtsevanos, G.: 'Seismic-mass" density-based algorithm for spatio-temporal clustering', Expert Systems with Applications, vol. 40 (10), pp. 4183-4189, 2013 [7] Konstantaras, A.: 'Classification of Distinct Seismic Regions and Regional Temporal Modelling of Seismicity in the Vicinity of the Hellenic Seismic Arc', Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of', vol. 99, pp. 1-7, 2013

Simultaneous Vibration Suppression and Energy Harvesting

DTIC Science & Technology

2013-08-15

D.J., 2011. “Modeling and Analysis of Piezoelectric Energy Harvesting from Aeroelastic Vibrations Using the Doublet-Lattice Method,” ASME Journal...Friswell, M. I., and Inman, D. J., 2009, “ Piezoelectric Energy Harvesting from Broadband Random Vibrations ,” Smart Materials and Structures, Vol. 18...and Electrode Configuration on Piezoelectric Energy Harvesting from Cantilevered Beams,” ASME Journal of Vibration and Acoustics, Vol. 131, No. 1, pp

Lower plate deformation structures along the Costa Rica erosive plate boundary - results from IODP Expedition 344 (CRISP 2)

NASA Astrophysics Data System (ADS)

Brandstätter, Jennifer; Kurz, Walter; Micheuz, Peter; Krenn, Kurt

2015-04-01

The primary objective of Integrated Ocean Drilling Program (IODP) Expedition 344 offshore the Osa Peninsula in Costa Rica was to sample and quantify the material entering the seismogenic zone of the Costa Rican erosive subduction margin. Fundamental to this objective is an understanding of the nature of both the subducting Cocos plate crust and of the overriding Caribbean plate. The subducting Cocos plate is investigated trying to define its hydrologic system and thermal state. The forearc structures recorded by the sediment deposited on the forearc, instead, document periods of uplift and subsidence and provide important information about the process of tectonic erosion that characterizes the Costa Rica margin. Offshore the western margin of Costa Rica, the oceanic Cocos plate subducts under the Caribbean plate, forming the southern end of the Middle America Trench. Subduction parameters including the age, convergence rate, azimuth, obliquity, morphology, and slab dip all vary along strike. The age of the Cocos plate at the Middle America Trench decreases from 24 Ma offshore the Nicoya Peninsula to 15 Ma offshore the Osa Peninsula. Subduction rates vary from 70 mm/y offshore Guatemala to 90 mm/y offshore southern Costa Rica. Convergence obliquity across the trench varies from offshore Nicaragua, where it is as much as 25° oblique, to nearly orthogonal southeast of the Nicoya Peninsula. Passage of the Cocos plate over the Galapagos hotspot created the aseismic Cocos Ridge, an overthickened welt of oceanic crust. This ridge is ~25 km thick, greater than three times normal oceanic crustal thickness. During IODP Expedition 344, the incoming Cocos plate was drilled at sites U1381 and U1414. Site U1381 is located ~4.5 km seaward of the deformation front offshore the Osa Peninsula and Caño Island. It is located on a local basement high. Basement relief often focuses fluid flow, so data from this site are likely to document the vigor of fluid flow in this area. Site U1414 is located ~1 km seaward of the deformation front offshore the Osa Peninsula and Caño Island. Primary science goals at Site U1414 included characterization of the alteration state of the magmatic basement. Brittle structures within the incoming plate (sites U1380, U1414) are mineralized extensional fractures and shear fractures. The shear fractures mainly show a normal component of shear. Within the sedimentary sequence both types of fractures dip steeply (vertical to subvertical) and strike NNE-SSW. Deformation bands trend roughly ENE-WSW, sub-parallel to the trend of the Cocos ridge. Structures in the Cocos Ridge basalt mainly comprise mineralized veins at various orientations. A preferred orientation of strike directions was not observed. Some veins show straight boundaries, others are characterized by an irregular geometry characterized by brecciated wall rock clasts embedded within vein precipitates. The vein mineralization was analysed in detail by RAMAN spectroscopy. Precipitation conditions and fluid chemistry were analysed by fluid inclusions entrapped within vein minerals. Vein mineralizations mainly consist of carbonate (fibrous aragonite, calcite), chalcedony, and quartz. Vein mineralization is mainly characterized by zoned antitaxial growth of carbonate fibres including a suture along the central vein domains. Quartz is often characterized by fibre growth of crystals perpendicular to the vein boundaries, too. These zoned veins additinally have wall rock alteration seams consisting of clay minerals. The precipitation sequence basically indicates that fluid chemistry evolved from an CO2-rich towards a SiO2- rich fluid.

Investigations in structural morphological and optical properties of Bi-Pb-S system thin films

NASA Astrophysics Data System (ADS)

Malika, Boukhalfa; Noureddine, Benramdane; Mourad, Medles; Abdelkader, Outzourhit; Attouya, Bouzidi; Hind, Tabet-derraz

Bi2S3, PbS and Bi-Pb-S system thin films were grown on glass substrates by the spray pyrolysis technique. The films growth was realized by the reaction of aqueous solutions of bismuth trichloride (BiCl3) and trihydrate Lead Acetate (TLA) (Pb(CH3COO)2.3H2O) with thiourea on heated substrates. The films study was performed as a function of the TLA volume ratio (TLA vol. ratio) in the solution obtained by the mixture of BiCl3 and thiourea used as precursor solution (PrS). X-ray diffraction (XRD), field emitting scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) were used for structural and compositional analysis of the as deposited films. With the structural investigations, Bi2S3, PbS thin films and PbS-Bi2S3 composite thin films formation was confirmed. Optical properties of the deposited films were obtained using transmittance and reflectance measurements in the wavelength range [200-2500 nm]. The absorption edge shows a shift towards low energy with the increase of the TLA vol. ratio.The optical bandgaps for the films with various TLA vol. ratio are found to lie between those of the Bi2S3 and PbS ones. The optical parameters (extinction coefficient, refractive index, real and imaginary parts if the complex dielectric constant) of the thin films are also investigated. These are found to be dependent on the TLA vol. ratio.

Discussion of the paper 'Hydrates offshore Brazil'

USGS Publications Warehouse

Dillon, William P.

1994-01-01

The paper “Hydrates Offshore Brazil” by Rogerio L. Fontana and Alexandre Mussumeci presents some important information that strongly indicates the presence of gas hydrates on the southern Brazilian continental margin. However, the acoustic compressional wave velocity structure reported for the Brazilian margin sediments is highly unusual and quite puzzling. We will discuss a possible explanation related to the presence of gas hydrate and free gas in the sediments.

Seabirds at risk around offshore oil platforms in the north-west Atlantic.

PubMed

Wiese, F K; Montevecchi, W A; Davoren, G K; Huettmann, F; Diamond, A W; Linke, J

2001-12-01

Seabirds aggregate around oil drilling platforms and rigs in above average numbers due to night lighting, flaring, food and other visual cues. Bird mortality has been documented due to impact on the structure, oiling and incineration by the flare. The environmental circumstances for offshore hydrocarbon development in North-west Atlantic are unique because of the harsh climate, cold waters and because enormous seabird concentrations inhabit and move through the Grand Banks in autumn (storm-petrels, Oceanodroma spp), winter (dovekies, Alle alle, murres, Uria spp), spring and summer (shearwaters, Puffinus spp). Many species are planktivorous and attracted to artificial light sources. Most of the seabirds in the region are long-distance migrants, and hydrocarbon development in the North-west Atlantic could affect both regional and global breeding populations. Regulators need to take responsibility for these circumstances. It is essential to implement comprehensive, independent arm's length monitoring of potential avian impacts of offshore hydrocarbon platforms in the North-west Atlantic. This should include quantifying and determining the nature, timing and extent of bird mortality caused by these structures. Based on existing evidence of potential impacts of offshore hydrocarbon platforms on seabirds, it is difficult to understand why this has not been, and is not being, systematically implemented.

A surface ice module for wind turbine dynamic response simulation using FAST

DOE PAGES

Yu, Bingbin; Karr, Dale G.; Song, Huimin; ...

2016-06-03

It is a fact that developing offshore wind energy has become more and more serious worldwide in recent years. Many of the promising offshore wind farm locations are in cold regions that may have ice cover during wintertime. The challenge of possible ice loads on offshore wind turbines raises the demand of modeling capacity of dynamic wind turbine response under the joint action of ice, wind, wave, and current. The simulation software FAST is an open source computer-aided engineering (CAE) package maintained by the National Renewable Energy Laboratory. In this paper, a new module of FAST for assessing the dynamicmore » response of offshore wind turbines subjected to ice forcing is presented. In the ice module, several models are presented which involve both prescribed forcing and coupled response. For conditions in which the ice forcing is essentially decoupled from the structural response, ice forces are established from existing models for brittle and ductile ice failure. For conditions in which the ice failure and the structural response are coupled, such as lock-in conditions, a rate-dependent ice model is described, which is developed in conjunction with a new modularization framework for FAST. In this paper, analytical ice mechanics models are presented that incorporate ice floe forcing, deformation, and failure. For lower speeds, forces slowly build until the ice strength is reached and ice fails resulting in a quasi-static condition. For intermediate speeds, the ice failure can be coupled with the structural response and resulting in coinciding periods of the ice failure and the structural response. A third regime occurs at high speeds of encounter in which brittle fracturing of the ice feature occurs in a random pattern, which results in a random vibration excitation of the structure. An example wind turbine response is simulated under ice loading of each of the presented models. This module adds to FAST the capabilities for analyzing the response of wind turbines subjected to forces resulting from ice impact on the turbine support structure. The conditions considered in this module are specifically addressed in the International Organization for Standardization (ISO) standard 19906:2010 for arctic offshore structures design consideration. Special consideration of lock-in vibrations is required due to the detrimental effects of such response with regard to fatigue and foundation/soil response. Finally, the use of FAST for transient, time domain simulation with the new ice module is well suited for such analyses.« less

Fatigue reassessment for lifetime extension of offshore wind monopile substructures

NASA Astrophysics Data System (ADS)

Ziegler, Lisa; Muskulus, Michael

2016-09-01

Fatigue reassessment is required to decide about lifetime extension of aging offshore wind farms. This paper presents a methodology to identify important parameters to monitor during the operational phase of offshore wind turbines. An elementary effects method is applied to analyze the global sensitivity of residual fatigue lifetimes to environmental, structural and operational parameters. Therefore, renewed lifetime simulations are performed for a case study which consists of a 5 MW turbine with monopile substructure in 20 m water depth. Results show that corrosion, turbine availability, and turbulence intensity are the most influential parameters. This can vary strongly for other settings (water depth, turbine size, etc.) making case-specific assessments necessary.

Indus basin off Pakistan contains few wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quadri, V.N.; Quadri, S.M.G.J.

1997-06-16

The U.N. Conference on the Law of the Sea reaffirmed sovereignty of nations over 22 km of territorial sea, a 370 km Exclusive Economic Zone (EEZ), and rights over the continental shelf to at least 370 km and out to 648 km or beyond under specified conditions. With a coast line of about 990 km, the EEZ for Pakistan extends over an area almost 240,000 sq km, or 40% of the land sedimentary area, in which two distinct geological provinces, and the Indus Offshore and the Makran offshore, have been defined. The paper discusses the tectonics, structure, exploration history, andmore » play types offshore Pakistan. Data show a potential for both oil and gas.« less

Structural Considerations of a 20MW Multi-Rotor Wind Energy System

NASA Astrophysics Data System (ADS)

Jamieson, P.; Branney, M.

2014-12-01

The drive to upscale offshore wind turbines relates especially to possiblereductions in O&M and electrical interconnection costs per MW of installed capacity.Even with best current technologies, designs with rated capacity above about 3 MW are less cost effective exfactory per rated MW(turbine system costs) than smaller machines.Very large offshore wind turbines are thereforejustifiedprimarily by overall offshore project economics. Furthermore, continuing progress in materials and structures has been essential to avoid severe penalties in the power/mass ratio of large multi-MW machines.The multi-rotor concept employs many small rotors to maximise energy capture area withminimum systemvolume. Previous work has indicated that this can enablea very large reduction in the total weight and cost of rotors and drive trains compared to an equivalent large single rotor system.Thus the multi rotor concept may enable rated capacities of 20 MW or more at a single maintenancesite. Establishing the cost benefit of a multi rotor system requires examination of solutions for the support structure and yawing, ensuring aerodynamic losses from rotor interaction are not significant and that overall logistics, with much increased part count (more reliable components) and less consequence of single failuresare favourable. This paper addresses the viability of a support structure in respect of structural concept and likely weight as one necessary step in exploring the potential of the multi rotor concept.

Effects of offshore platforms on soft-bottom macro-benthic assemblages: a case study in a Mediterranean gas field.

PubMed

Terlizzi, Antonio; Bevilacqua, Stanislao; Scuderi, Danilo; Fiorentino, Dario; Guarnieri, Giuseppe; Giangrande, Adriana; Licciano, Margherita; Felline, Serena; Fraschetti, Simonetta

2008-07-01

The exploitation of fossil fuels in the Mediterranean Sea will likely lead to an increase in the number of offshore platforms, a recognized threat for marine biodiversity. To date, in this basin, few attempts have been made to assess the impact of offshore gas and oil platforms on the biodiversity of benthic assemblages. Here, we adopted a structured experimental design coupled with high taxonomic resolution to outline putative effects of gas platforms on soft-bottom macrofauna assemblages in the North Ionian Sea. The analysis was based on a total of 20,295 specimens of 405 taxa, almost entirely identified at species level. Multivariate and univariate analyses showed idiosyncratic patterns of assemblage change with increasing distance from the platforms. Potential reasons underlying such inconsistency are analyzed and the view that structured experimental monitoring is a crucial tool to quantify the extent and magnitude of potential threats and to provide sound baseline information on biodiversity patterns is supported.

Structural health and prognostics management for the enhancement of offshore wind turbine operations and maintenance strategies

DOE PAGES

Griffith, D. Todd; Yoder, Nathanael C.; Resor, Brian; ...

2013-09-19

Offshore wind turbines are an attractive source for clean and renewable energy for reasons including their proximity to population centers and higher capacity factors. One obstacle to the more widespread installation of offshore wind turbines in the USA, however, is that recent projections of offshore operations and maintenance costs vary from two to five times the land-based costs. One way in which these costs could be reduced is through use of a structural health and prognostics management (SHPM) system as part of a condition-based maintenance paradigm with smart loads management. Our paper contributes to the development of such strategies bymore » developing an initial roadmap for SHPM, with application to the blades. One of the key elements of the approach is a multiscale simulation approach developed to identify how the underlying physics of the system are affected by the presence of damage and how these changes manifest themselves in the operational response of a full turbine. A case study of a trailing edge disbond is analysed to demonstrate the multiscale sensitivity of damage approach and to show the potential life extension and increased energy capture that can be achieved using simple changes in the overall turbine control and loads management strategy. Finally, the integration of health monitoring information, economic considerations such as repair costs versus state of health, and a smart loads management methodology provides an initial roadmap for reducing operations and maintenance costs for offshore wind farms while increasing turbine availability and overall profit.« less

Integrity management of offshore structures and its implication on computation of structural action effects and resistance

NASA Astrophysics Data System (ADS)

Moan, T.

2017-12-01

An overview of integrity management of offshore structures, with emphasis on the oil and gas energy sector, is given. Based on relevant accident experiences and means to control the associated risks, accidents are categorized from a technical-physical as well as human and organizational point of view. Structural risk relates to extreme actions as well as structural degradation. Risk mitigation measures, including adequate design criteria, inspection, repair and maintenance as well as quality assurance and control of engineering processes, are briefly outlined. The current status of risk and reliability methodology to aid decisions in the integrity management is briefly reviewed. Finally, the need to balance the uncertainties in data, methods and computational efforts and the cautious use and quality assurance and control in applying high fidelity methods to avoid human errors, is emphasized, and with a plea to develop both high fidelity as well as efficient, simplified methods for design.

New Insights Into Valley Formation and Preservation: Geophysical Imaging of the Offshore Trinity River Paleovalley

NASA Astrophysics Data System (ADS)

Speed, C. M.; Swartz, J. M.; Gulick, S. P. S.; Goff, J.

2017-12-01

The Trinity River paleovalley is an offshore stratigraphic structure located on the inner continental shelf of the Gulf of Mexico offshore Galveston, Texas. Its formation is linked to the paleo-Trinity system as it existed across the continental shelf during the last glacial period. Newly acquired high-resolution geophysical data have imaged more complexity to the valley morphology and shelf stratigraphy than was previously captured. Significantly, the paleo-Trinity River valley appears to change in the degree of confinement and relief relative to the surrounding strata. Proximal to the modern shoreline, the interpreted time-transgressive erosive surface formed by the paleo-river system is broad and rugose with no single valley, but just 5 km farther offshore the system appears to become confined to a 10 km wide valley structure before again becoming unconfined once again 30 km offshore. Fluvial stratigraphy in this region has a similar degree of complexity in morphology and preservation. A dense geophysical survey of several hundred km is planned for Fall 2017, which will provide unprecedented imaging of the paleovalley morphology and associated stratigraphy. Our analysis leverages robust chirp processing techniques that allow for imaging of strata on the decimeter scale. We will integrate our geophysical results with a wide array of both newly collected and previously published sediment cores. This approach will allow us to address several key questions regarding incised valley formation and preservation on glacial-interglacial timescales including: to what extent do paleo-rivers remain confined within a single broad valley structure, what is the fluvial systems response to transgression, and what stratigraphy is created and preserved at the transition from fluvial to estuarine environments? Our work illustrates that traditional models of incised valley formation and subsequent infilling potentially fail to capture the full breadth of dynamics of past river systems.

33 CFR 148.400 - What does this subpart do?

Code of Federal Regulations, 2012 CFR

2012-07-01

... topographic and geologic structure of the ocean bottom to determine its ability to support offshore structures and other equipment; and (3) Studies done for the preparation of the environmental analysis required...

Structural Changes and Material Transport in Al2O3-Supported Cu/Fe Spinel Particles in a Simulated Chemical Looping Combustion Environment

NASA Astrophysics Data System (ADS)

Nealley, W. H. Harrison; Nakano, Anna; Nakano, Jinichiro; Bennett, James P.

2018-05-01

Alumina-supported Cu/Fe spinel particles were exposed to oxidation/reduction atmospheres at 800°C. Structural changes of the particles subjected to gas cycles between air and 10 vol.% CO-90 vol.% Ar were studied from physical data and real-time images collected using a confocal scanning laser microscope equipped with a heating chamber. Overall particle volume slowly expanded with cycles while surface roughness decreased. Cross-sections of the exposed particles showed segregation of Cu and Fe to the edges of inner grains, which may have acted as oxygen carriers during the exposures. The particles remained whole during the cyclic exposures without any noticeable structural breakdown.

Critical Factors Analysis for Offshore Software Development Success by Structural Equation Modeling

NASA Astrophysics Data System (ADS)

Wada, Yoshihisa; Tsuji, Hiroshi

In order to analyze the success/failure factors in offshore software development service by the structural equation modeling, this paper proposes to follow two approaches together; domain knowledge based heuristic analysis and factor analysis based rational analysis. The former works for generating and verifying of hypothesis to find factors and causalities. The latter works for verifying factors introduced by theory to build the model without heuristics. Following the proposed combined approaches for the responses from skilled project managers of the questionnaire, this paper found that the vendor property has high causality for the success compared to software property and project property.

Aspects of structural health and condition monitoring of offshore wind turbines

PubMed Central

Antoniadou, I.; Dervilis, N.; Papatheou, E.; Maguire, A. E.; Worden, K.

2015-01-01

Wind power has expanded significantly over the past years, although reliability of wind turbine systems, especially of offshore wind turbines, has been many times unsatisfactory in the past. Wind turbine failures are equivalent to crucial financial losses. Therefore, creating and applying strategies that improve the reliability of their components is important for a successful implementation of such systems. Structural health monitoring (SHM) addresses these problems through the monitoring of parameters indicative of the state of the structure examined. Condition monitoring (CM), on the other hand, can be seen as a specialized area of the SHM community that aims at damage detection of, particularly, rotating machinery. The paper is divided into two parts: in the first part, advanced signal processing and machine learning methods are discussed for SHM and CM on wind turbine gearbox and blade damage detection examples. In the second part, an initial exploration of supervisor control and data acquisition systems data of an offshore wind farm is presented, and data-driven approaches are proposed for detecting abnormal behaviour of wind turbines. It is shown that the advanced signal processing methods discussed are effective and that it is important to adopt these SHM strategies in the wind energy sector. PMID:25583864

Aspects of structural health and condition monitoring of offshore wind turbines.

PubMed

Antoniadou, I; Dervilis, N; Papatheou, E; Maguire, A E; Worden, K

2015-02-28

Wind power has expanded significantly over the past years, although reliability of wind turbine systems, especially of offshore wind turbines, has been many times unsatisfactory in the past. Wind turbine failures are equivalent to crucial financial losses. Therefore, creating and applying strategies that improve the reliability of their components is important for a successful implementation of such systems. Structural health monitoring (SHM) addresses these problems through the monitoring of parameters indicative of the state of the structure examined. Condition monitoring (CM), on the other hand, can be seen as a specialized area of the SHM community that aims at damage detection of, particularly, rotating machinery. The paper is divided into two parts: in the first part, advanced signal processing and machine learning methods are discussed for SHM and CM on wind turbine gearbox and blade damage detection examples. In the second part, an initial exploration of supervisor control and data acquisition systems data of an offshore wind farm is presented, and data-driven approaches are proposed for detecting abnormal behaviour of wind turbines. It is shown that the advanced signal processing methods discussed are effective and that it is important to adopt these SHM strategies in the wind energy sector.

Predicting recreational fishing use of offshore petroleum platforms in the Central Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, W.R. Jr.

1987-01-01

This study is based on the premise that properly sited artificial reefs for optimal human recreational use, a predictive model based upon the marine travel patterns and behavior of marine recreational fishermen, is needed. This research used data gathered from a previous study that addressed the recreational fishing use of offshore oil and gas structures (Ditton and Auyong 1984); on-site data were also collected. The primary research objective was to generate a predictive model that can be applied to artificial-reef development efforts elsewhere. This study investigated the recreational-user patterns of selected petroleum platforms structures in the Central Gulf of Mexico.more » The petroleum structures offshore from the Louisiana coastline provide a unique research tool. Although intended to facilitate the exploration and recovery of hydrocarbons, petroleum platforms also serve as defacto artificial reefs, providing habitat for numerous species of fish and other marine life. Petroleum platforms were found to be the principal fishing destinations within the study area. On-site findings reveal that marine recreational fishermen were as mobile on water, as they are on land. On-site findings were used to assist in the development of a predictive model.« less

Seismotetonics of the Eastern Taiwan offshore area from OBS data

NASA Astrophysics Data System (ADS)

Chin, S.; Lin, J.

2013-12-01

Located at the arc-continental collision region between the Eurasian (EU) and Philippine Sea Plate (PSP), Taiwan is characterized by a complex tectonic environment, especially the eastern part of the island. Based on geodetic, geological and geophysical data, the tectonic structures in the eastern Taiwan have been well studied by several former works. However, the seismotectonic structures in the offshore area of eastern Taiwan are still poorly understood, because most seismic stations are inland and the earthquakes occur offshore cannot be located accurately. To understand the seismic activities in the offshore area of the eastern Taiwan, we deployed 8 OBSs (Ocean Bottom Seismometer) from Jul. 9th to Aug. 3rd, 2012 to record the seismic signal. The continuous waveform data recorded by the CWB (Central Weather Bureau) land stations were also used to increase the precision of the hypocenter determination. Seismic events were detected manually and the Antelope software and the global velocity model iasp91 (Kennett and Engdahl, 1991) were used for the initial localization. As a result, a total of 714 events were located in the previous 17-day data. Because of the complexity of the crustal structures around Taiwan, a 1-D seismic velocity model is not accurate sufficiently for a reliable hypocenter determination. For improving the precision of the location, we relocated the earthquakes with the HypoDD relocation method (Waldhauser and Ellsworth, 2000) which could minimize errors result from the velocity structure without the use of station corrections. Finally, 306 events were relocated successfully. Compared with the earthquakes determined by the Taiwanese seismic network (CWB and BATS- Broadband Array in Taiwan for Seismology), our preliminary result has a similar seismic pattern with these two catalogs but contains much more offshore earthquakes in the same time period. The relocated earthquakes show an east-dipping seismic zone in the southern part of eastern Taiwan (about 22.8°N-23.4°N) which is consistent with the published tomographic and seismic distribution (Malavielle et al., 2002; Wu et al., 2007; Kuochen et al., 2012). Further north (near 23.5°N), a west-dipping seismic structure at a depth of 25-60 km corresponds to the northwestward collision or subduction of part of the PSP (Chemenda et al., 2001; Lallemand et al., 2001 and 2013). Moreover, it is obvious that the presence of a NW-SE trending seismic pattern at 30-40 km depth in the eastern offshore area of the Coastal Range (CR). Further investigation on the focal mechanism and the geological evidence is required to understand the origin and the role of this seismic feature.

Methodes de calcul des forces aerodynamiques pour les etudes des interactions aeroservoelastiques

NASA Astrophysics Data System (ADS)

Biskri, Djallel Eddine

L'aeroservoelasticite est un domaine ou interagissent la structure flexible d'un avion, l'aerodynamique et la commande de vol. De son cote, la commande du vol considere l'avion comme une structure rigide et etudie l'influence du systeme de commande sur la dynamique de vol. Dans cette these, nous avons code trois nouvelles methodes d'approximation de forces aerodynamiques: Moindres carres corriges, Etat minimal corrige et Etats combines. Dans les deux premieres methodes, les erreurs d'approximation entre les forces aerodynamiques approximees par les methodes classiques et celles obtenues par les nouvelles methodes ont les memes formes analytiques que celles des forces aerodynamiques calculees par LS ou MS. Quant a la troisieme methode, celle-ci combine les formulations des forces approximees avec les methodes standards LS et MS. Les vitesses et frequences de battement et les temps d'executions calcules par les nouvelles methodes versus ceux calcules par les methodes classiques ont ete analyses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rashid, A.; Nygaard, C.

The use of concrete in marine environment has gained tremendous popularity in the past decade and is continued to be a very popular material for marine industry in the world today. It has a very diversified use from large offshore platforms and floating structures in the North Sea, Canada and South America to offshore loading terminals and junction platforms in shallow waters in the marshes of southern Louisiana in the Gulf of Mexico. Also, precast concrete sections are extensively used all over the world in the construction of marine structures. Because of their large variety of shapes and sizes, theymore » can be tailored to fit multiple applications in marine environment. The added quality control in the fabrication yard and the ease of installation by lifting makes them a very attractive option. The use of precast concrete sections is gaining a lot of popularity in South America. A lot of fabrication yards are manufacturing these sections locally. There are hundreds of offshore concrete platforms utilizing these sections in Lake Maracaibo, Venezuela. The paper discusses the use of concrete for offshore structures including floaters. It describes some general concepts and advantages to be gained by the use of concrete (precast and cast-in-place) in marine environment. It also discusses some general design considerations required for the use of different types of precast concrete sections that can be utilized for oil and gas platforms and loading terminals. Lastly the paper describes some typical examples of concrete platforms built out of concrete piles, precast concrete girders and beam sections and concrete decking.« less

A vector auto-regressive model for onshore and offshore wind synthesis incorporating meteorological model information

NASA Astrophysics Data System (ADS)

Hill, D.; Bell, K. R. W.; McMillan, D.; Infield, D.

2014-05-01

The growth of wind power production in the electricity portfolio is striving to meet ambitious targets set, for example by the EU, to reduce greenhouse gas emissions by 20% by 2020. Huge investments are now being made in new offshore wind farms around UK coastal waters that will have a major impact on the GB electrical supply. Representations of the UK wind field in syntheses which capture the inherent structure and correlations between different locations including offshore sites are required. Here, Vector Auto-Regressive (VAR) models are presented and extended in a novel way to incorporate offshore time series from a pan-European meteorological model called COSMO, with onshore wind speeds from the MIDAS dataset provided by the British Atmospheric Data Centre. Forecasting ability onshore is shown to be improved with the inclusion of the offshore sites with improvements of up to 25% in RMS error at 6 h ahead. In addition, the VAR model is used to synthesise time series of wind at each offshore site, which are then used to estimate wind farm capacity factors at the sites in question. These are then compared with estimates of capacity factors derived from the work of Hawkins et al. (2011). A good degree of agreement is established indicating that this synthesis tool should be useful in power system impact studies.

Influence of occupational stress on mental health among Chinese off-shore oil workers.

PubMed

Chen, Wei-Qing; Wong, Tze-Wai; Yu, Tak-Sun

2009-09-01

To explore the influence of occupational stress on mental health in off-shore oil production. A cross-sectional survey was conducted among 561 Chinese off-shore oil workers. The workers were invited to fill in a self-administered questionnaire exploring their socio-demographic characteristics, occupational stress levels, and 12-item general health questionnaire. A hierarchical multiple regression procedure was used to assess the effects of occupational stress on mental health. After controlling for age, educational level, marital status and years of off-shore work, poor mental health was found to have a significant positive association with seven of the nine identified sources of occupational stress. They were: conflict between job and family/social life, poor development of career and achievement at work, safety problems at work, management problems and poor relationship with others at work, poor physical environment of the work place, uncomfortable ergonomic factors at work, and poor organizational structure at work. All of these occupational stress sources together explained 19.9% of the total variance. The results confirmed that occupational stress was a major risk factor for poor mental health among Chinese off-shore oil workers. Reducing or eliminating occupational stressors at work would benefit workers' mental health.

RADIATION DOSE AND RISK TO RECREATIONAL FISHERMEN FROM INGESTION OF FISH CAUGHT NEAR EIGHT OIL PLATFORMS IN THE GULF OF MEXICO

DOE Office of Scientific and Technical Information (OSTI.GOV)

MEINHOLD,A.F.; HOLTZMAN,S.

1998-06-01

Offshore production of oil and gas is accompanied by a saline wastewater, called produced water. Produced water discharges to the Gulf of Mexico often contain elevated concentrations of radionuclides that occur naturally in the geologic reservoir along with the oil and gas. These radionuclides may accumulate in organisms that live near offshore oil and gas structures. Because recreational fishing in the Gulf of Mexico is concentrated near oil and gas platforms, there is the potential for increased risks to recreational fishermen from the ingestion of radionuclides in fish caught near produced water discharges. This analysis investigated the potential risk tomore » recreational fishermen from radium and lead-210 in offshore produced water discharges to the Gulf of Mexico. The assessment used data collected at eight discharging offshore platforms and two reference locations. These data were collected in a USDOE funded project titled ``Environmental and Economic Assessment of Discharges from Gulf of Mexico Region Oil and Gas Operations'', here called the USDOE Field Study. The risk assessments were done to support risk managers in developing regulations and permits for offshore discharges of produced water.« less

Artificial reef effect in relation to offshore renewable energy conversion: state of the art.

PubMed

Langhamer, Olivia

2012-01-01

The rapid worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization, thus acting as artificial reefs. The artificial reef effect is important when constructing, for example, scour protections since it can generate an enhanced habitat. Specifically, artificial structures can create increased heterogeneity in the area important for species diversity and density. Offshore energy installations also have the positive side effect as they are a sanctuary area for trawled organisms. Higher survival of fish and bigger fish is an expected outcome that can contribute to a spillover to outer areas. One negative side effect is that invasive species can find new habitats in artificial reefs and thus influence the native habitats and their associated environment negatively. Different scour protections in offshore wind farms can create new habitats compensating for habitat loss by offshore energy installations. These created habitats differ from the lost habitat in species composition substantially. A positive reef effect is dependent on the nature and the location of the reef and the characteristics of the native populations. An increase in surface area of scour protections by using specially designed material can also support the reef effect and its productivity.

Artificial Reef Effect in relation to Offshore Renewable Energy Conversion: State of the Art

PubMed Central

2012-01-01

The rapid worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization, thus acting as artificial reefs. The artificial reef effect is important when constructing, for example, scour protections since it can generate an enhanced habitat. Specifically, artificial structures can create increased heterogeneity in the area important for species diversity and density. Offshore energy installations also have the positive side effect as they are a sanctuary area for trawled organisms. Higher survival of fish and bigger fish is an expected outcome that can contribute to a spillover to outer areas. One negative side effect is that invasive species can find new habitats in artificial reefs and thus influence the native habitats and their associated environment negatively. Different scour protections in offshore wind farms can create new habitats compensating for habitat loss by offshore energy installations. These created habitats differ from the lost habitat in species composition substantially. A positive reef effect is dependent on the nature and the location of the reef and the characteristics of the native populations. An increase in surface area of scour protections by using specially designed material can also support the reef effect and its productivity. PMID:23326215

Motion performance and mooring system of a floating offshore wind turbine

NASA Astrophysics Data System (ADS)

Zhao, Jing; Zhang, Liang; Wu, Haitao

2012-09-01

The development of offshore wind farms was originally carried out in shallow water areas with fixed (seabed mounted) structures. However, countries with limited shallow water areas require innovative floating platforms to deploy wind turbines offshore in order to harness wind energy to generate electricity in deep seas. The performances of motion and mooring system dynamics are vital to designing a cost effective and durable floating platform. This paper describes a numerical model to simulate dynamic behavior of a new semi-submersible type floating offshore wind turbine (FOWT) system. The wind turbine was modeled as a wind block with a certain thrust coefficient, and the hydrodynamics and mooring system dynamics of the platform were calculated by SESAM software. The effect of change in environmental conditions on the dynamic response of the system under wave and wind loading was examined. The results indicate that the semi-submersible concept has excellent performance and SESAM could be an effective tool for floating wind turbine design and analysis.

Sea loads on ships and offshore structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faltinsen, O.

1990-01-01

The book introduces the theory of the structural loading on ships and offshore structures caused by wind, waves and currents, and goes on to describe the applications of this theory in terms of real structures. The main topics described are linear-wave induced motions, loads on floating structures, numerical methods for ascertaining wave induced motions and loads, viscous wave loads and damping, stationkeeping and water impact and entry. The applications of the theoretical principles are introduced with extensive use of exercises and examples. Applications covered include conventional ships, barges, high speed marine vehicles, semisubmersibles, tension leg platforms, moored or dynamic positionedmore » ships, risers, buoys, fishing nets, jacket structures and gravity platforms. One aim of the book is to provide a physical understanding through simplified mathematical models. In this way one can develop analytical tools to evaluate results from test models, full scale trials or computer simulation, and learns which parameters represent the major contributions and influences on sea loads.« less

Recent deformation along the offshore Malibu Coast, Dume, and related faults west of Point Dume, southern California

USGS Publications Warehouse

Fisher, M.A.; Langenheim, V.E.; Sorlien, C.C.; Dartnell, P.; Sliter, R.W.; Cochrane, G.R.; Wong, F.L.

2005-01-01

Offshore faults west of Point Dume, southern California, are part of an important regional fault system that extends for about 206 km, from near the city of Los Angeles westward along the south flank of the Santa Monica Mountains and through the northern Channel Islands. This boundary fault system separates the western Transverse Ranges, on the north, from the California Continental Borderland, on the south. Previous research showed that the fault system includes many active fault strands; consequently, the entire system is considered a serious potential earthquake hazard to nearby Los Angeles. We present an integrated analysis of multichannel seismic- and high-resolution seismic-reflection data and multibeam-bathymetric information to focus on the central part of the fault system that lies west of Point Dume. We show that some of the main offshore faults have cumulative displacements of 3-5 km, and many faults are currently active because they deform the seafloor or very shallow sediment layers. The main offshore fault is the Dume fault, a large north-dipping reverse fault. In the eastern part of the study area, this fault offsets the seafloor, showing Holocene displacement. Onshore, the Malibu Coast fault dips steeply north, is active, and shows left-oblique slip. The probable offshore extension of this fault is a large fault that dips steeply in its upper part but flattens at depth. High-resolution seismic data show that this fault deforms shallow sediment making up the Hueneme fan complex, indicating Holocene activity. A structure near Sycamore knoll strikes transversely to the main faults and could be important to the analysis of the regional earthquake hazard because the structure might form a boundary between earthquake-rupture segments.

Spreading and slope instability at the continental margin offshore Mt Etna, imaged by high-resolution 2D seismic data

NASA Astrophysics Data System (ADS)

Gross, Felix; Krastel, Sebastian; Behrmann, Jan-Hinrich; Papenberg, Cord; Geersen, Jacob; Ridente, Domenico; Latino Chiocci, Francesco; Urlaub, Morelia; Bialas, Jörg; Micallef, Aaron

2015-04-01

Mount Etna is the largest active volcano in Europe. Its volcano edifice is located on top of continental crust close to the Ionian shore in east Sicily. Instability of the eastern flank of the volcano edifice is well documented onshore. The continental margin is supposed to deform as well. Little, however, is known about the offshore extension of the eastern volcano flank and its adjacent continental margin, which is a serious shortcoming in stability models. In order to better constrain the active tectonics of the continental margin offshore the eastern flank of the volcano, we acquired and processed a new marine high-resolution seismic and hydro-acoustic dataset. The data provide new detailed insights into the heterogeneous geology and tectonics of shallow continental margin structures offshore Mt Etna. In a similiar manner as observed onshore, the submarine realm is characterized by different blocks, which are controlled by local- and regional tectonics. We image a compressional regime at the toe of the continental margin, which is bound to an asymmetric basin system confining the eastward movement of the flank. In addition, we constrain the proposed southern boundary of the moving flank, which is identified as a right lateral oblique fault movement north of Catania Canyon. From our findings, we consider a major coupled volcano edifice instability and continental margin gravitational collapse and spreading to be present at Mt Etna, as we see a clear link between on- and offshore tectonic structures across the entire eastern flank. The new findings will help to evaluate hazards and risks accompanied by Mt Etna's slope- and continental margin instability and will be used as a base for future investigations in this region.

Recursive thoughts on the simulation of the flexible multibody dynamics of slender offshore structures

NASA Astrophysics Data System (ADS)

Schilder, J.; Ellenbroek, M.; de Boer, A.

2017-12-01

In this work, the floating frame of reference formulation is used to create a flexible multibody model of slender offshore structures such as pipelines and risers. It is shown that due to the chain-like topology of the considered structures, the equation of motion can be expressed in terms of absolute interface coordinates. In the presented form, kinematic constraint equations are satisfied explicitly and the Lagrange multipliers are eliminated from the equations. Hence, the structures can be conveniently coupled to finite element or multibody models of for example seabed and vessel. The chain-like topology enables the efficient use of recursive solution procedures for both transient dynamic analysis and equilibrium analysis. For this, the transfer matrix method is used. In order to improve the convergence of the equilibrium analysis, the analytical solution of an ideal catenary is used as an initial configuration, reducing the number of required iterations.

Fluid-structure interaction simulation of floating structures interacting with complex, large-scale ocean waves and atmospheric turbulence with application to floating offshore wind turbines

NASA Astrophysics Data System (ADS)

Calderer, Antoni; Guo, Xin; Shen, Lian; Sotiropoulos, Fotis

2018-02-01

We develop a numerical method for simulating coupled interactions of complex floating structures with large-scale ocean waves and atmospheric turbulence. We employ an efficient large-scale model to develop offshore wind and wave environmental conditions, which are then incorporated into a high resolution two-phase flow solver with fluid-structure interaction (FSI). The large-scale wind-wave interaction model is based on a two-fluid dynamically-coupled approach that employs a high-order spectral method for simulating the water motion and a viscous solver with undulatory boundaries for the air motion. The two-phase flow FSI solver is based on the level set method and is capable of simulating the coupled dynamic interaction of arbitrarily complex bodies with airflow and waves. The large-scale wave field solver is coupled with the near-field FSI solver with a one-way coupling approach by feeding into the latter waves via a pressure-forcing method combined with the level set method. We validate the model for both simple wave trains and three-dimensional directional waves and compare the results with experimental and theoretical solutions. Finally, we demonstrate the capabilities of the new computational framework by carrying out large-eddy simulation of a floating offshore wind turbine interacting with realistic ocean wind and waves.

River Flow Impacts Bacterial and Archaeal Community Structure in Surface Sediments in the Northern Gulf of Mexico.

PubMed

Ortmann, Alice C; Brannock, Pamela M; Wang, Lei; Halanych, Kenneth M

2018-04-17

Meiobenthic community structure in the northern Gulf of Mexico has been shown to be driven by geographical differences due to inshore-offshore gradients and location relative to river discharge. Samples collected along three transects spanning Mobile Bay, Alabama, showed significant differences in meiobenthic communities east of the bay compared to those sampled from the west. In contrast, analysis of bacterial and archaeal communities from the same sediment samples shows that the inshore-offshore gradient has minimal impact on their community structure. Significant differences in community structure were observed for Bacteria and Archaea between the east and west samples, but there was no difference in richness or diversity. Grouped by sediment type, higher richness was observed in silty samples compared to sandy samples. Significant differences were also observed among sediment types for community structure with bacteria communities in silty samples having more anaerobic sulfate reducers compared to aerobic heterotrophs, which had higher abundances in sandy sediments. This is likely due to increased organic matter in the silty sediments from the overlying river leading to low oxygen habitats. Most archaeal sequences represented poorly characterized high-level taxa, limiting interpretation of their distributions. Overlap between groups based on transect and sediment characteristics made determining which factor is more important in structuring bacterial and archaeal communities difficult. However, both factors are driven by discharge from the Mobile River. Although inshore-offshore gradients do not affect Bacteria or Archaea to the same extent as the meiobenthic communities, all three groups are strongly affected by sediment characteristics.

Velocity and Structure Estimation of a Moving Object Using a Moving Monocular Camera

DTIC Science & Technology

2006-01-01

map the Euclidean position of static landmarks or visual features in the environment . Recent applications of this technique include aerial...From Motion in a Piecewise Planar Environment ,” International Journal of Pattern Recognition and Artificial Intelligence, Vol. 2, No. 3, pp. 485-508...1988. [9] J. M. Ferryman, S. J. Maybank , and A. D. Worrall, “Visual Surveil- lance for Moving Vehicles,” Intl. Journal of Computer Vision, Vol. 37, No

Numerical Simulation of the Interaction of a Vortex with Stationary Airfoil in Transonic Flow,

DTIC Science & Technology

1984-01-12

Goorjian, P. M., "Implicit Vortex Wakes ," AIAA Journal, Vol. 15, No. 4, April Finite- Difference Computations of Unsteady Transonic 1977, pp. 581-590... Difference Simulations of Three- tion of Wing- Vortex Interaction in Transonic Flow Dimensional Flow," AIAA Journal, Vol. 18, No. 2, Using Implicit...assumptions are made in p = density modeling the nonlinear vortex wake structure. Numerical algorithms based on the Euler equations p_ = free stream density

Differential Multiscale Modeling of Chemically Complex Materials under Heavy Deformation: Biological, Bioinspired and Synthetic Hierarchical Materials

DTIC Science & Technology

2010-06-01

Buehler, “Meso- Origami : Folding Multilayer Graphene Sheets”, Applied Physics Letters, Vol. 95, paper #: 123121, 2009 D. Sen and M.J. Buehler, “Size and... geometry effects on flow stress in bioinspired de novo metal-matrix nanocomposites”, Advanced Engineering Materials, Vol. 11(10), pp. 774-781, 2009...behavior is recovered. Second, a subset of all geometries shows the inverse banana curve behavior. Interestingly, only 2% of all structures give the

Interactions Between the Cross-Shore Structure of Small Pelagic Fish Population, Offshore Industrial Fisheries and Near Shore Artisanal Fisheries: A Mathematical Approach.

PubMed

Mchich, Rachid; Brochier, Timothée; Auger, Pierre; Brehmer, Patrice

2016-12-01

This work presents a mathematical model describing the interactions between the cross-shore structure of small pelagic fish population an their exploitation by coastal and offshore fisheries. The complete model is a system of seven ODE's governing three stocks of small pelagic fish population moving and growing between three zones. Two types of fishing fleets are inter-acting with the fish population, industrial boats, constrained to offshore area, and artisanal boats, operating from the shore. Two time scales were considered and we use aggregation methods that allow us to reduce the dimension of the model and to obtain an aggregated model, which is a four dimension one. The analysis of the aggregated model is performed. We discuss the possible equilibriums and their meaning in terms of fishery management. An interesting equilibrium state can be obtained for which we can expect coexistence and a stable equilibrium state between fish stocks and fishing efforts. Some identification parameters are also given in the discussion part of the model.

Development of fast wireless detection system for fixed offshore platform

NASA Astrophysics Data System (ADS)

Li, Zhigang; Yu, Yan; Jiao, Dong; Wang, Jie; Li, Zhirui; Ou, Jinping

2011-04-01

Offshore platforms' security is concerned since in 1950s and 1960s, and in the early 1980s some important specifications and standards are built, and all these provide technical basis of fixed platform design, construction, installation and evaluation. With the condition that more and more platforms are in serving over age, the research about the evaluation and detection technology of offshore platform has been a hotspot, especially underwater detection, and assessment method based on the finite element calculation. For fixed platform structure detection, conventional NDT methods, such as eddy current, magnetic powder, permeate, X-ray and ultrasonic, etc, are generally used. These techniques are more mature, intuitive, but underwater detection needs underwater robot, the necessary supporting tools of auxiliary equipment, and trained professional team, thus resources and cost used are considerable, installation time of test equipment is long. This project presents a new kind of fast wireless detection and damage diagnosis system for fixed offshore platform using wireless sensor networks, that is, wireless sensor nodes can be put quickly on the offshore platform, detect offshore platform structure global status by wireless communication, and then make diagnosis. This system is operated simply, suitable for offshore platform integrity states rapid assessment. The designed system consists in intelligence acquisition equipment and 8 wireless collection nodes, the whole system has 64 collection channels, namely every wireless collection node has eight 16-bit accuracy of A/D channels. Wireless collection node, integrated with vibration sensing unit, embedded low-power micro-processing unit, wireless transceiver unit, large-capacity power unit, and GPS time synchronization unit, can finish the functions such as vibration data collection, initial analysis, data storage, data wireless transmission. Intelligence acquisition equipment, integrated with high-performance computation unit, wireless transceiver unit, mobile power unit and embedded data analysis software, can totally control multi-wireless collection nodes, receive and analyze data, parameter identification. Data is transmitted at the 2.4GHz wireless communication channel, every sensing data channel in charge of data transmission is in a stable frequency band, control channel responsible for the control of power parameters is in a public frequency band. The test is initially conducted for the designed system, experimental results show that the system has good application prospects and practical value with fast arrangement, high sampling rate, high resolution, capacity of low frequency detection.

The vertical structure of the circulation and dynamics in Hudson Shelf Valley

USGS Publications Warehouse

Lentz, Steven J.; Butman, Bradford; Harris, Courtney K.

2014-01-01

Hudson Shelf Valley is a 20–30 m deep, 5–10 km wide v-shaped submarine valley that extends across the Middle Atlantic Bight continental shelf. The valley provides a conduit for cross-shelf exchange via along-valley currents of 0.5 m s−1 or more. Current profile, pressure, and density observations collected during the winter of 1999–2000 are used to examine the vertical structure and dynamics of the flow. Near-bottom along-valley currents having times scales of a few days are driven by cross-shelf pressure gradients setup by wind stresses, with eastward (westward) winds driving onshore (offshore) flow within the valley. The along-valley momentum balance in the bottom boundary layer is predominantly between the pressure gradient and bottom stress because the valley bathymetry limits current veering. Above the bottom boundary layer, the flow veers toward an along-shelf (cross-valley) orientation and a geostrophic balance with some contribution from the wind stress (surface Ekman layer). The vertical structure and strength of the along-valley current depends on the magnitude and direction of the wind stress. During offshore flows driven by westward winds, the near-bottom stratification within the valley increases resulting in a thinner bottom boundary layer and weaker offshore currents. Conversely, during onshore flows driven by eastward winds the near-bottom stratification decreases resulting in a thicker bottom boundary layer and stronger onshore currents. Consequently, for wind stress magnitudes exceeding 0.1 N m−2, onshore along-valley transport associated with eastward wind stress exceeds the offshore transport associated with westward wind stress of the same magnitude.

Pulling the rug out from under California: Seismic images of the Mendocino Triple Junction region

USGS Publications Warehouse

Tréhu, Anne M.

1995-01-01

In 1993 and 1994 a network of large-aperture seismic profiles was collected to image the crustal and upper-mantle structure beneath northern California and the adjacent continental margin. The data include approximately 650 km of onshore seismic refraction/reflection data, 2000 km of off-shore multichannel seismic (MCS) reflection data, and simultaneous onshore and offshore recording of the MCS airgun source to yield large-aperture data. Scientists from more than 12 institutions were involved in data acquisition.

Offshore Installations and Their Relevance to the Coast Guard through the Next Twenty-Five Years. Volume I. Basic Report: Forecast of Offshore Installations and Their Implications to the Coast Guard.

DTIC Science & Technology

1980-11-01

institution to impose charges on members of the Coast Guard’s constituency who benefit from Coast Guard sevices --i.e. establish user charges and value... Sex Ratio - Externalities * Labor Force - Relation to economic growth - Nature and number - Man’s welfare - Participation rate - Productivity rate...Pollution characterisitcs - Sex distribution Radioactive e By Country Thermal Toxic 9 Structure Contanimant - Stratification Long run/short run

Offshore Installations and Their Relevance to the Coast Guard through the Next Twenty-Five Years. Volume II. Detailed Forecasts.

DTIC Science & Technology

1980-11-01

Deposits Red Clay/ooze Argonite deposits Manganese Nodules Minerals susceptible to gas/liquid conversion Salt Potash Minerals from Icebergs 1-7 Figure 1-2...in general, and from the arctic and antartic regions in particular; o Increased safety and security on offshore structures exposed to hazardous...Minerals present as or which may be converted Salt to liquids or gases Potash Minerals from icebergs BACKGROUND In many respects, particularly in processing

Numerical tools to predict the environmental loads for offshore structures under extreme weather conditions

NASA Astrophysics Data System (ADS)

Wu, Yanling

2018-05-01

In this paper, the extreme waves were generated using the open source computational fluid dynamic (CFD) tools — OpenFOAM and Waves2FOAM — using linear and nonlinear NewWave input. They were used to conduct the numerical simulation of the wave impact process. Numerical tools based on first-order (with and without stretching) and second-order NewWave are investigated. The simulation to predict force loading for the offshore platform under the extreme weather condition is implemented and compared.

Cape Cod Easterly Shore Beach Erosion Study. Volume 2

DTIC Science & Technology

1979-04-01

exploration leases in itself does not affect land use, but the discovery of oil , gas , or minerals offshore can have a major impact on the coast if...Structures - A few seasonal cottages are located s) uth of and on the southeast side of Little Pochet Island (Figure 1-G3). They are reached by jeep trail...unknown, but many of the offshore islands and submerged banks of the area are of glacial origin. Noteworthy examples are the Nantucket shoals southeast

Evaluation of coated columbium alloy heat shields for space shuttle thermal protection system application. Volume 3, phase 3: Full size TPS evaluation

NASA Technical Reports Server (NTRS)

Baer, J. W.; Black, W. E.

1974-01-01

The thermal protection system (TPS), designed for incorporation with space shuttle orbiter systems, consists of one primary heat shield thermally and structurally isolated from the test fixture by eight peripheral guard panels, all encompassing an area of approximately 12 sq ft. TPS components include tee-stiffened Cb 752/R-512E heat shields, bi-metallic support posts, panel retainers, and high temperature insulation blankets. The vehicle primary structure was simulated by a titanium skin, frames, and stiffeners. Test procedures, manufacturing processes, and methods of analysis are fully documented. For Vol. 1, see N72-30948; for Vol. 2, see N74-15660.

Trophic connections in Lake Superior Part I: the offshore fish community

USGS Publications Warehouse

Gamble, A.E.; Hrabik, T.R.; Stockwell, J.D.; Yule, D.L.

2011-01-01

Detailed diet linkages within the offshore (> 80 m bathymetric depth) food web of Lake Superior are currently not well identified. We used analyses of fish stomach contents to create an empirically based food web model of the Lake Superior offshore fish community. Stomachs were collected seasonally (spring, summer, and fall) from nine offshore locations in 2005, using bottom and midwater trawls. In total, 2643 stomachs representing 12 fish species were examined. The predominant fish species collected were deepwater sculpin (Myoxocephalus thompsonii), siscowet (Salvelinus namaycush siscowet), kiyi (Coregonus kiyi), and cisco (Coregonus artedi). Mysis diluviana was the most common prey item, indicating that changes in Mysis abundance could have a profound impact on the entire offshore food web. Mysis was the primary diet item of deepwater sculpin (≥ 53% by mass) and kiyi (≥ 96% by mass) regardless of depth or season. The invasive Bythotrephes was an important diet component of the pelagic cisco in summer and fall. Deepwater sculpin were the primary diet item of siscowet (≥ 52% by mass), with coregonines appearing in the diet of larger (> 400 mm) siscowet. Non-metric multidimensional scaling analysis indicated that there were no statistically significant seasonal or site-specific differences in diets of deepwater sculpin, cisco, or kiyi. Site was the primary structuring factor in siscowet diets. Generally, in Lake Superior, the diet items of the dominant offshore species did not appear to be in danger from those types of major ecological shifts occurring in the lower Laurentian Great Lakes.

The Offshore New European Wind Atlas

NASA Astrophysics Data System (ADS)

Karagali, I.; Hahmann, A. N.; Badger, M.; Hasager, C.; Mann, J.

2017-12-01

The New European Wind Atlas (NEWA) is a joint effort of research agencies from eight European countries, co-funded under the ERANET Plus Program. The project is structured around two areas of work: development of dynamical downscaling methodologies and measurement campaigns to validate these methodologies, leading to the creation and publication of a European wind atlas in electronic form. This atlas will contain an offshore component extending 100 km from the European coasts. To achieve this, mesoscale models along with various observational datasets are utilised. Scanning lidars located at the coastline were used to compare the coastal wind gradient reproduced by the meso-scale model. Currently, an experimental campaign is occurring in the Baltic Sea, with a lidar located in a commercial ship sailing from Germany to Lithuania, thus covering the entire span of the south Baltic basin. In addition, satellite wind retrievals from scatterometers and Synthetic Aperture Radar (SAR) instruments were used to generate mean wind field maps and validate offshore modelled wind fields and identify the optimal model set-up parameters.The aim of this study is to compare the initial outputs from the offshore wind atlas produced by the Weather & Research Forecasting (WRF) model, still in pre-operational phase, and the METOP-A/B Advanced Scatterometer (ASCAT) wind fields, reprocessed to stress equivalent winds at 10m. Different experiments were set-up to evaluate the model sensitivity for the various domains covered by the NEWA offshore atlas. ASCAT winds were utilised to assess the performance of the WRF offshore atlases. In addition, ASCAT winds were used to create an offshore atlas covering the years 2007 to 2016, capturing the signature of various spatial wind features, such as channelling and lee effects from complex coastal topographical elements.

Organizational Structures for International Universities: Implications for Campus Autonomy, Academic Freedom, Collegiality, and Conflict

ERIC Educational Resources Information Center

Edwards, Ron; Crosling, Glenda; Lim, Ngat-Chin

2014-01-01

One significant form of transnational higher education is the International Branch Campus (IBC), in effect an "outpost" of the parent institution located in another country. Its organizational structure is alignable with offshore subsidiaries of multinational corporations (MNCs). The implications of organizational structure for academic…

Moving And Working On Space Structures

NASA Technical Reports Server (NTRS)

Mclaughlin, Pat B.

1992-01-01

Clawlike device attaches boots to rails. Memorandum presents, in sketches and brief text, concept for boot-toe clip helping astronaut move about outside on structures being built at Space Station. Clip also helps astronaut maintain stable position at worksite. Concept adaptable to underwater work on such structures as offshore oil rigs.

Radiation dose and risk to recreational fishermen from ingestion of fish caught near eight oil platforms in the Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meinhold, A.F.; Holtzman, S.

1998-06-01

Offshore production of oil and gas is accompanied by a saline wastewater, called produced water. Produced water discharges to the Gulf of Mexico often contain elevated concentrations of radionuclides that occur naturally in the geologic reservoir along with the oil and gas. These radionuclides may accumulate in organisms that live near offshore oil and gas structures. Because recreational fishing in the Gulf of Mexico is concentrated near oil and gas platforms, there is the potential for increased risks to recreational fishermen from the ingestion of radionuclides in fish caught near produced water discharges. This analysis investigated the potential risk tomore » recreational fishermen from radium and lead-210 in offshore produced water discharged to the Gulf of Mexico.« less

Magnetic properties of Japan Sea sediments in areas which host shallow gas hydrates and in relation to the the amount of gas hydrate

NASA Astrophysics Data System (ADS)

Shimono, T.; Matsumoto, R.

2016-12-01

Shallow gas hydrate is known to occur as massive nodular aggregates in subsurface and/or shallow marine sediments (e.g. Matsumoto et al. 2009). We conducted a rock magnetic study of marine core sediments to clarify the relationship between shallow gas hydrate and the surrounding sediments. The core samples were taken from around Oki area and offshore Joetsu, the eastern margin of Japan Sea, during PS15 cruise in 2015. We mainly report magnetic susceptibility measurement of whole-round core samples. From the onboard measurements, the magnetic susceptibilities of gas hydrates indicated diamagnetic mineral like water or ice ( -0.9 x 10-5 vol. SI). Moreover, we introduce a method to assess the amount of gas hydrate present within marine sediments using magnetic susceptibility and rock magnetic analyses. This study was conducted under the commission from AIST as a part of the methane hydrate research project of METI (the Ministry of Economy, Trade and Industry, Japan).

Isotope and fatty acid trends along continental shelf depth gradients: Inshore versus offshore hydrological influences on benthic trophic functioning

NASA Astrophysics Data System (ADS)

Chouvelon, T.; Schaal, G.; Grall, J.; Pernet, F.; Perdriau, M.; A-Pernet, E. J.; Le Bris, H.

2015-11-01

Anthropogenic activities and land-based inputs into the sea may influence the trophic structure and functioning of coastal and continental shelf ecosystems, despite the numerous opportunities and services the latter offer to humans and wildlife. In addition, hydrological structures and physical dynamics potentially influence the sources of organic matter (e.g., terrestrial versus marine, or fresh material versus detrital material) entering marine food webs. Understanding the significance of the processes that influence marine food webs and ecosystems (e.g., terrestrial inputs, physical dynamics) is crucially important because trophic dynamics are a vital part of ecosystem integrity. This can be achieved by identifying organic matter sources that enter food webs along inshore-offshore transects. We hypothesised that regional hydrological structures over wide continental shelves directly control the benthic trophic functioning across the shelf. We investigated this issue along two transects in the northern ecosystem of the Bay of Biscay (north-eastern Atlantic). Carbon and nitrogen stable isotope analysis (SIA) and fatty acid analysis (FAA) were conducted on different complementary ecosystem compartments that include suspended particulate organic matter (POM), sedimentary organic matter (SOM), and benthic consumers such as bivalves, large crustaceans and demersal fish. Samples were collected from inshore shallow waters (at ∼1 m in depth) to more than 200 m in depth on the offshore shelf break. Results indicated strong discrepancies in stable isotope (SI) and fatty acid (FA) compositions in the sampled compartments between inshore and offshore areas, although nitrogen SI (δ15N) and FA trends were similar along both transects. Offshore the influence of a permanently stratified area (described previously as a ;cold pool;) was evident in both transects. The influence of this hydrological structure on benthic trophic functioning (i.e., on the food sources available for consumers) was especially apparent across the northern transect, due to unusual carbon isotope compositions (δ13C) in the compartments. At stations under the cold pool, SI and FA organism compositions indicated benthic trophic functioning based on a microbial food web, including a significant contribution of heterotrophic planktonic organisms and/or of SOM, notably in stations under the cold pool. On the contrary, inshore and shelf break areas were characterised by a microalgae-based food web (at least in part for the shelf break area, due to slope current and upwelling that can favour fresh primary production sinking on site). SIA and FAA were relevant and complementary tools, and consumers better medium- to long-term system integrators than POM samples, for depicting the trophic functioning and dynamics along inshore-offshore transects over continental shelves.

Tectonic structure and petroleum potential of TayabasBay southeast Luzon, Philippines

NASA Astrophysics Data System (ADS)

Bacud, Jaime; Moore, Aidan; Lee, Chao-Skiing

Tayabas Bay is one of four offshore Philippine areas where the Australian GeologicalSurvey Organization and the Philippine Department of Energy conducted a cooperative marine seismic, gravity, magnetic, bathymetry and geochemical survey. The project acquired new seismic data and reprocessed the 1983 World Bank seismic sections which were all integrated with previous oil company data. the absence of wells drilled offshore, interpretation of offshore seismic data was complemented by onshore well log information and stratigraphy of the Bondoc Peninsula. Geochemistry data, both offshore and onshore, were analyzed to confirm the presence of mature source rocks and hydrocarbon migration. A new seismic interpretation has revealed the structure of this tectonically active geologically complex area. A major structural feature interpreted in offshore Tayabas Bay was a N-NW-trending strike-slip fault which is believed to be a northern splay of the Sibuyan Sea Fault. The authors named this fault the Tayabas Bay Fault and due to its association with the Philippine Fault System the movement is assumed to be left-lateral. The present study suggested the presence of a prolific source rock in the Middle Miocene Vigo Formation and/or the Late Oligocene to Early Miocene Panaon Limestone. Oil and gas generation have been and are occurring in the Bondoc Sub-basin. Two groups of reservoirs were identified, the shelf carbonates beneath the Middle Miocene shales on the Marinduque Platform and the early Middle Miocene carbonates and basin-floor clastics near the base of the Vigo Formation. Carbonate reservoirs are believed to be present in traps formed when the Late Oligocene to Early Miocene carbonate reefs and shelf deposits of the Panaon Limestone were buried by the Middle Miocene shales. A later set of traps was formed and possibly superimposed by the intense deformation associated with the Philippine Fault System which has continued from the Late Pliocene up to the present. Evaluation for hydrocarbon reserves of several possible traps identified three significant leads, namely the Yuni Lead in the south, the Mulanay in the central area and the Mabio in the North.

Assessing Fish and Motile Fauna around Offshore Windfarms Using Stereo Baited Video

PubMed Central

Griffin, Ross A.; Robinson, Gary J.; West, Ashley; Gloyne-Phillips, Ian T.; Unsworth, Richard K. F.

2016-01-01

There remains limited knowledge of how offshore windfarm developments influence fish assemblages, particularly at a local scale around the turbine structures. Considering the existing levels of anthropogenic pressures on coastal fish populations it is becoming increasingly important for developers and environmental regulators to gain a more comprehensive understanding of the factors influencing fish assemblages. Improving our ability to assess such fish populations in close proximity to structures will assist in increasing this knowledge. In the present study we provide the first trial use of Baited Remote Underwater Stereo-Video systems (stereo BRUVs) for the quantification of motile fauna in close proximity to offshore wind turbines. The study was conducted in the Irish Sea and finds the technique to be a viable means of assessing the motile fauna of such environments. The present study found a mixture of species including bottom dwellers, motile crustaceans and large predatory fish. The majority of taxa observed were found to be immature individuals with few adult individuals recorded. The most abundant species were the angular crab (Goneplax rhomboides) and the small-spotted catshark (Scyliorhinus canicula). Of note in this study was the generally low abundance and diversity of taxa recorded across all samples, we hypothesise that this reflects the generally poor state of the local fauna of the Irish Sea. The faunal assemblages sampled in close proximity to turbines were observed to alter with increasing distance from the structure, species more characteristic of hard bottom environments were in abundance at the turbines (e.g. Homarus gammarus, Cancer pagarus, Scyliorhinus spp.) and those further away more characteristic of soft bottoms (e.g. Norwegian Lobster). This study highlights the need for the environmental impacts of offshore renewables on motile fauna to be assessed using targeted and appropriate tools. Stereo BRUVs provide one of those tools, but like the majority of methods for sampling marine biota, they have limitations. We conclude our paper by providing a discussion of the benefits and limitations of using this BRUV technique for assessing fauna within areas close to offshore windfarms. PMID:26934587

Fabrication and Characterization of Three Dimensional Photonic Crystals Generated by Multibeam Interference Lithography

DTIC Science & Technology

2009-01-01

and J. A. Lewis, "Microperiodic structures - Direct writing of three-dimensional webs ," Nature, vol. 428, pp. 386-386, 2004. [9] M. Campbell, D. N...of Applied Physics Part 1-Regular Papers Brief Communications & Review Papers , vol. 44, pp. 6355-6367, 2005. [75] P. Cloetens, W. Ludwig, J... paper screen on the sample holder and marking the beam position. If the central beam is properly aligned, the spot on the screen remains at the

Structure of the Extended Emission in the Infrared Celestial Background,

DTIC Science & Technology

1986-09-30

the energy cascade to smaller sizes due to turbulence. Such a steep function would predict little energy in microfilaments at the resolution of a meter...Neugebauer, H.H. Aumann, N. Boggess, J.P. Emerson, J.R. Fuck , B.T. Soifer and R.G. Walker, "IRAS Observations of the Diffuse Infrared Background", Astrophys. J...Astrcphys., Vol. 100, 116, 1981. " 80. Little , S.J. and S.D. Price, "Infrared Mapping of the Galactic Plane. IV. The Galactic Center", Astron. J., Vol

Surface electrical properties experiment, Part 3

NASA Technical Reports Server (NTRS)

1974-01-01

A complete unified discussion of the electromagnetic response of a plane stratified structure is reported. A detailed and comprehensive analysis of the theoretical parts of the electromagnetic is given. The numerical problem of computing numbers of the electromagnetic field strengths is discussed. It is shown that the analysis of the conductive media is not very far removed from the theoretical analysis and the numerical difficulties are not as accute as for the low-loss problem. For Vol. 1, see N75-15570; for Vol. 2 see N75-15571.

Characterization of Residual Stress as a Function of Friction Stir Welding Parameters in ODS Steel MA956

DTIC Science & Technology

2013-06-01

dispersion strengthened - Eurofer steel ,” J. Nucl. Mater., vol. 416 , pp. 2229, Sep 1, 2011. [10] H. J. K. Lemmen and K. J. Sudmeijer, I, “Laser beam...Reynolds and W. Tang, “Structure, properties, and residual stress of 304L stainless steel friction stir welds,” Scr. Mater., vol. 48, pp. 12891294...OF RESIDUAL STRESS AS A FUNCTION OF FRICTION STIR WELDING PARAMETERS IN ODS STEEL MA956 by Martin S. Bennett June 2013 Thesis Advisor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kennedy, R.P.; Kincaid, R.H.; Short, S.A.

This report presents the results of part of a two-task study on the engineering characterization of earthquake ground motion for nuclear power plant design. Task I of the study, which is presented in NUREG/CR-3805, Vol. 1, developed a basis for selecting design response spectra taking into account the characteristics of free-field ground motion found to be significant in causing structural damage. Task II incorporates additional considerations of effects of spatial variations of ground motions and soil-structure interaction on foundation motions and structural response. The results of Task II are presented in four parts: (1) effects of ground motion characteristics onmore » structural response of a typical PWR reactor building with localized nonlinearities and soil-structure interaction effects; (2) empirical data on spatial variations of earthquake ground motion; (3) soil-structure interaction effects on structural response; and (4) summary of conclusions and recommendations based on Tasks I and II studies. This report presents the results of the first part of Task II. The results of the other parts will be presented in NUREG/CR-3805, Vols. 3 to 5.« less

Reorganization of a marine trophic network along an inshore-offshore gradient due to stronger pelagic-benthic coupling in coastal areas

NASA Astrophysics Data System (ADS)

Kopp, Dorothée; Lefebvre, Sébastien; Cachera, Marie; Villanueva, Maria Ching; Ernande, Bruno

2015-01-01

Recent theoretical considerations have highlighted the importance of the pelagic-benthic coupling in marine food webs. In continental shelf seas, it was hypothesized that the trophic network structure may change along an inshore-offshore gradient due to weakening of the pelagic-benthic coupling from coastal to offshore areas. We tested this assumption empirically using the eastern English Channel (EEC) as a case study. We sampled organisms from particulate organic matter to predatory fishes and used baseline-corrected carbon and nitrogen stable isotope ratios (δ13C and δ15N) to determine their trophic position. First, hierarchical clustering on δ13C and δ15N coupled to bootstrapping and estimates of the relative contribution of pelagic and benthic carbon sources to consumers' diet showed that, at mesoscale, the EEC food web forms a continuum of four trophic levels with trophic groups spread across a pelagic and a benthic trophic pathway. Second, based on the same methods, a discrete approach examined changes in the local food web structure across three depth strata in order to investigate the inshore-offshore gradient. It showed stronger pelagic-benthic coupling in shallow coastal areas mostly due to a reorganization of the upper consumers relative to the two trophic pathways, benthic carbon sources being available to pelagic consumers and, reciprocally, pelagic sources becoming accessible to benthic species. Third a continuous approach examined changes in the mean and variance of upper consumers' δ13C and δ15N with depth. It detected a significant decrease in δ13C variance and a significant increase in δ15N variance as depth increases. A theoretical two-source mixing model showed that an inshore-offshore decrease in the pelagic-benthic coupling was a sufficient condition to produce the δ13C variance pattern, thus supporting the conclusions of the discrete approach. These results suggest that environmental gradients such as the inshore-offshore one should be accounted for to better understand marine food webs dynamics.

Microstructural, textural, and sensory characteristics of probiotic yogurts fortified with sodium calcium caseinate or whey protein concentrate.

PubMed

Akalın, A S; Unal, G; Dinkci, N; Hayaloglu, A A

2012-07-01

The influence of milk protein-based ingredients on the textural characteristics, sensory properties, and microstructure of probiotic yogurt during a refrigerated storage period of 28 d was studied. Milk was fortified with 2% (wt/vol) skim milk powder as control, 2% (wt/vol) sodium calcium caseinate (SCaCN), 2% (wt/vol) whey protein concentrate (WPC) or a blend of 1% (wt/vol) SCaCN and 1% (wt/vol) WPC. A commercial yogurt starter culture and Bifidobacterium lactis Bb12 as probiotic bacteria were used for the production. The fortification with SCaCN improved the firmness and adhesiveness. Higher values of viscosity were also obtained in probiotic yogurts with SCaCN during storage. However, WPC enhanced water-holding capacity more than the caseinate. Addition of SCaCN resulted in a coarse, smooth, and more compact protein network; however, WPC gave finer and bunched structures in the scanning electron microscopy micrographs. The use of SCaCN decreased texture scores in probiotic yogurt; probably due to the lower water-holding capacity and higher syneresis values in the caseinate-added yogurt sample. Therefore, the textural characteristics of probiotic yogurts improved depending on the ingredient variety. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The Influence of Inherited Topography and/or Tectonics on Paleo-channel Systems and Incised Valleys Offshore of South Carolina

NASA Astrophysics Data System (ADS)

Long, A. M.; Hill, J. C.

2016-12-01

The Quaternary paleo-channel and incised valley systems of the Southeastern United States have been well documented onshore; however, few studies have focused on the positions and fill histories of these systems on the continental shelf. The effects of inherited topography can be studied through the integration of seismo-acoustic and core data. Existing offshore datasets have been used to document underlying structural and stratigraphic fabrics deeper than the Quaternary in the sedimentary record. By integrating these results with the published tectonic setting and onshore interpretations, some of the controls on paleo-channel/incised valley positions can be inferred. Preliminary results suggest the stress caused by the uplift along the Cape Fear Arch has been accommodated by shallow folding and reactivation of deeper structures in the South Carolina offshore province. The resultant topography may have dictated both the position and geometry of the fluvial incisions across the shelf. This in turn influences the accommodation space available to be filled in as sea level fluctuates. The depositional facies within the paleo-channel and incised valley range from single, uninterrupted fill to complex and repeated scour and fill with at least four different episodes of erosion and deposition. The observations and interpretations proposed here are the first steps in unraveling the complex interplay between sea level, climate, and tectonic changes on the morphology and stratigraphy of incised valleys and paleo-channels observed offshore of South Carolina.

A structural scheme proposal derived from geophysical data in the epicentral area of the Boumerdes (Algeria) earthquake of May 21, 2003

NASA Astrophysics Data System (ADS)

Samai, Saddek; Idres, Mouloud; Ouyed, Merzouk; Bourmatte, Amar; Boughacha, Mohamed Salah; Bezzeghoud, Mourad; Borges, José Fernando

2017-09-01

In this study, we processed and interpreted gravity and aeromagnetic data of the epicentral area of the Boumerdes earthquake (May 21, 2003). The joint interpretation of both data allowed the development of a structural scheme that shows the basement undulations offshore and onshore. The shape of the eastern part of the Mitidja Basin is better defined; its northern edge is represented by a large ;sub-circular; uplifted basement located offshore. The rise of this basement indicates that this basin does not extend towards the sea. At the eastern part of the study area, aeromagnetic data have revealed that the Sid-Ali-Bounab basement is individualized in a ;sub-circular; shape, while the Dellys basement, located in the NE part, is elongated in the NE-SW direction and extends offshore. The aeromagnetic data also highlighted two EW basement uplifts which divide Isser depression into three parts. The northern part of this depression extends offshore. The southernmost uplift is an extension of the Thenia Fault (TF), suggesting the continuity of this fault to the east. It is important to note that the active Reghaia Fault (RF), which runs through the Boudouaou and Reghaia urban centers, is bounded by two faults suggesting that its length does not exceed 12 km. Moreover, alluvial terraces observed west of the active Zemmouri Fault (ZF) are in agreement with the reverse component of this fault.

Magnetic anomalies northeast of Cape Adare, northern Victoria Land (Antarctica), and their relation to onshore structures

USGS Publications Warehouse

Damaske, D.; Läufer, A.L.; Goldmann, F.; Möller, H.-D.; Lisker, F.

2007-01-01

An aeromagnetic survey was flown over the offshore region northeast of Cape Adare and the magnetic anomalies compared to onshore structures between Pennell Coast and Tucker Glacier. The magnetic anomalies show two nearly orthogonal major trends. NNW-SSE trending anomalies northeast of Cape Adare represent seafloor spreading within the Adare Trough. A connection of these anomalies to the Northern Basin of the Ross Sea is not clear. Onshore faults are closely aligned to offshore anomalies. Main trends are NW-SE to NNW-SSE and NE-SW to NNESSW. NNW-SSE oriented dextral-transtensional to extensional faults parallel the Adare Peninsula and Adare Trough anomalies. NE-SW trending normal faults appear to segment the main Hallett volcanic bodies.

Risk management in the North sea offshore industry: History, status and challenges

NASA Astrophysics Data System (ADS)

Smith, E. J.

1995-10-01

There have been major changes in the UK and Norwegian offshore safety regimes in the last decade. On the basis of accumulated experience (including some major accidents), there has been a move away from a rigid, prescriptive approach to setting safety standards; it is now recognised that a more flexible, "goal-setting" approach is more suited to achieving cost-effective solutions to offshore safety. In order to adapt to this approach, offshore operators are increasingly using Quantitative Risk Assessment (QRA) techniques as part of their risk management programmes. Structured risk assessment can be used at all stages of a project life-cycle. In the design stages (concept and detailed design), these techniques are valuable tools in ensuring that money is wisely spent on safety-related systems. In the operational stage, QRA can aid the development of procedures. High quality Safety Management Systems (SMSs), covering issues such as training, inspection, and emergency planning, are crucial to maintain "asdesigned" levels of safety and reliability. Audits of SMSs should be carried out all through the operational phase to ensure that risky conditions do not accumulate.

Conceptual design and thermal analysis of a modular cryostat for one single coil of a 10 MW offshore superconducting wind turbine

NASA Astrophysics Data System (ADS)

Sun, Jiuce; Sanz, Santiago; Neumann, Holger

2015-12-01

Superconducting generators show the potential to reduce the head mass of large offshore wind turbines. A 10 MW offshore superconducting wind turbine has been investigated in the SUPRAPOWER project. The superconducting coils based on MgB2 tapes are supposed to work at cryogenic temperature of 20 K. In this paper, a novel modular rotating cryostat was presented for one single coil of the superconducting wind turbine. The modular concept and cryogen-free cooling method were proposed to fulfil the requirements of handling, maintenance, reliability of long term and offshore operations. Two stage Gifford-McMahon cryocoolers were used to provide cooling source. Supporting rods made of titanium alloy were selected as support structures of the cryostat in aim of reducing the heat load. The thermal performance in the modular cryostat was carefully investigated. The heat load applied to the cryocooler second stage was 2.17 W@20 K per coil. The corresponding temperature difference along the superconducting coil was only around 1 K.

Application of GNSS Methods for Monitoring Offshore Platform Deformation

NASA Astrophysics Data System (ADS)

Myint, Khin Cho; Nasir Matori, Abd; Gohari, Adel

2018-03-01

Global Navigation Satellite System (GNSS) has become a powerful tool for high-precision deformation monitoring application. Monitoring of deformation and subsidence of offshore platform due to factors such as shallow gas phenomena. GNSS is the technical interoperability and compatibility between various satellite navigation systems such as modernized GPS, Galileo, reconstructed GLONASS to be used by civilian users. It has been known that excessive deformation affects platform structurally, causing loss of production and affects the efficiency of the machinery on board the platform. GNSS have been proven to be one of the most precise positioning methods where by users can get accuracy to the nearest centimeter of a given position from carrier phase measurement processing of GPS signals. This research is aimed at using GNSS technique, which is one of the most standard methods to monitor the deformation of offshore platforms. Therefore, station modeling, which accounts for the spatial correlated errors, and hence speeds up the ambiguity resolution process is employed. It was found that GNSS combines the high accuracy of the results monitoring the offshore platforms deformation with the possibility of survey.

Study on dynamic characteristics of hydraulic pumping unit on offshore platform

NASA Astrophysics Data System (ADS)

Chang, Zong-yu; Yu, Yan-qun; Qi, Yao-guang

2017-12-01

A new technology of offshore oil rod pumping production is developed for offshore heavy oil recovery. A new type of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure is designed based on the spatial characteristics of offshore platforms. By combining the strengths of sinusoidal velocity curve and trapezoidal velocity curve, a kinematical model of the acceleration, the velocity and displacement of the pumping unit's hanging point is established. The results show that the pumping unit has good kinematic characteristics of smooth motion and small dynamic load. The multi-degree-of-freedom dynamic model of the single-well pumping unit is established. The first and second order natural frequencies of the sucker rod string subsystem and the pumping unit subsystem are studied. The results show that the first and the second order natural frequencies among the pumping rod string, pumping unit-platform subsystem and the dynamic excitation have differences over 5 times from each other, indicating that resonance phenomenon will not appear during the operation and the dynamic requirements for field use are met in the system.

Structural Health Monitoring challenges on the 10-MW offshore wind turbine model

NASA Astrophysics Data System (ADS)

Di Lorenzo, E.; Kosova, G.; Musella, U.; Manzato, S.; Peeters, B.; Marulo, F.; Desmet, W.

2015-07-01

The real-time structural damage detection on large slender structures has one of its main application on offshore Horizontal Axis Wind Turbines (HAWT). The renewable energy market is continuously pushing the wind turbine sizes and performances. This is the reason why nowadays offshore wind turbines concepts are going toward a 10 MW reference wind turbine model. The aim of the work is to perform operational analyses on the 10-MW reference wind turbine finite element model using an aeroelastic code in order to obtain long-time-low- cost simulations. The aeroelastic code allows simulating the damages in several ways: by reducing the edgewise/flapwise blades stiffness, by adding lumped masses or considering a progressive mass addiction (i.e. ice on the blades). The damage detection is then performed by means of Operational Modal Analysis (OMA) techniques. Virtual accelerometers are placed in order to simulate real measurements and to estimate the modal parameters. The feasibility of a robust damage detection on the model has been performed on the HAWT model in parked conditions. The situation is much more complicated in case of operating wind turbines because the time periodicity of the structure need to be taken into account. Several algorithms have been implemented and tested in the simulation environment. They are needed in order to carry on a damage detection simulation campaign and develop a feasible real-time damage detection method. In addition to these algorithms, harmonic removal tools are needed in order to dispose of the harmonics due to the rotation.

Development of structural health monitoring techniques using dynamics testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

James, G.H. III

Today`s society depends upon many structures (such as aircraft, bridges, wind turbines, offshore platforms, buildings, and nuclear weapons) which are nearing the end of their design lifetime. Since these structures cannot be economically replaced, techniques for structural health monitoring must be developed and implemented. Modal and structural dynamics measurements hold promise for the global non-destructive inspection of a variety of structures since surface measurements of a vibrating structure can provide information about the health of the internal members without costly (or impossible) dismantling of the structure. In order to develop structural health monitoring for application to operational structures, developments inmore » four areas have been undertaken within this project: operational evaluation, diagnostic measurements, information condensation, and damage identification. The developments in each of these four aspects of structural health monitoring have been exercised on a broad range of experimental data. This experimental data has been extracted from structures from several application areas which include aging aircraft, wind energy, aging bridges, offshore structures, structural supports, and mechanical parts. As a result of these advances, Sandia National Laboratories is in a position to perform further advanced development, operational implementation, and technical consulting for a broad class of the nation`s aging infrastructure problems.« less

Multiple tuned mass damper based vibration mitigation of offshore wind turbine considering soil-structure interaction

NASA Astrophysics Data System (ADS)

Hussan, Mosaruf; Sharmin, Faria; Kim, Dookie

2017-08-01

The dynamics of jacket supported offshore wind turbine (OWT) in earthquake environment is one of the progressing focuses in the renewable energy field. Soil-structure interaction (SSI) is a fundamental principle to analyze stability and safety of the structure. This study focuses on the performance of the multiple tuned mass damper (MTMD) in minimizing the dynamic responses of the structures objected to seismic loads combined with static wind and wave loads. Response surface methodology (RSM) has been applied to design the MTMD parameters. The analyses have been performed under two different boundary conditions: fixed base (without SSI) and flexible base (with SSI). Two vibration modes of the structure have been suppressed by multi-mode vibration control principle in both cases. The effectiveness of the MTMD in reducing the dynamic response of the structure is presented. The dynamic SSI plays an important role in the seismic behavior of the jacket supported OWT, especially resting on the soft soil deposit. Finally, it shows that excluding the SSI effect could be the reason of overestimating the MTMD performance.

Regional chloride distribution in the Northern Atlantic Coastal Plain aquifer system from Long Island, New York, to North Carolina

USGS Publications Warehouse

Charles, Emmanuel

2016-08-31

Although additional offshore chloride data are available compared to 27 years ago (1989), the offshore information remains sparse, resulting in less confidence in the offshore interpretations than in the onshore interpretations. Regionally, the 250- and 10,000-mg/L isochlors tend to map progressively eastward from the deepest to the shallowest aquifers across the Northern Atlantic Coastal Plain aquifer system but with some exceptions. The additional data, conceptual understanding, and interpretations in the vicinity of the buried Chesapeake Bay impact structure in eastern Virginia resulted in substantial refinement of isochlors in that area. Overall, the interpretations in this study are updates of the previous regional study from 1989 but do not comprise major differences in interpretation and do not indicate regional movement of the freshwater-saltwater interface since then.

Measuring attachment to life in old age: the Portuguese version of the Positive Valuation of Life Scale (Positive VOL).

PubMed

Araújo, Lia; Ribeiro, Oscar; Teixeira, Laetitia; Azevedo, Maria João; Jopp, Daniela S; Rott, Christoph; Paúl, Constança

2015-10-01

This study aims to present the psychometric properties of the Portuguese version of the Positive Valuation of Life Scale (Lawton et al. in J Aging Ment Healt 13:3-31, 2001). Sample included 207 community-dwelling elders (129 women; M Age = 77.2 years, SD = 7.5). The data collection included the translated and adapted Portuguese version of Positive Valuation of Life Scale, Life Satisfaction Index Z, Meaning in Life Questionnaire and Geriatric Depression Scale. From exploratory factor analysis, two factors emerged, existential beliefs and perceived control, explaining 49 % of the total variance. Both factors were positively related with meaning in life and life satisfaction and negatively related with depression (p < 0.05). The values obtained for internal consistency for the total scale and for each subscale were good (α > 0.75). The Portuguese version of Positive VOL Scale represents a reliable and valid measure to capture the subjective experience of attachment to one's life. The two-factor structure is an update to Lawton's previous work and in line with findings obtained in the USA (Dennis et al. in What is valuation of life for frail community-dwelling older adults: factor structure and criterion validity of the VOL, Thomas Jefferson University, Center for Applied Research on Aging and Health Research, 2005) and Japan (Nakagawa et al. in Shinrigaku Kenkyu 84:37-46, 2013). Future research is required to investigate VOL predictors and the potential changes toward the end of the life span.

Ionic Liquid-Doped Gel Polymer Electrolyte for Flexible Lithium-Ion Polymer Batteries

PubMed Central

Zhang, Ruisi; Chen, Yuanfen; Montazami, Reza

2015-01-01

Application of gel polymer electrolytes (GPE) in lithium-ion polymer batteries can address many shortcomings associated with liquid electrolyte lithium-ion batteries. Due to their physical structure, GPEs exhibit lower ion conductivity compared to their liquid counterparts. In this work, we have investigated and report improved ion conductivity in GPEs doped with ionic liquid. Samples containing ionic liquid at a variety of volume percentages (vol %) were characterized for their electrochemical and ionic properties. It is concluded that excess ionic liquid can damage internal structure of the batteries and result in unwanted electrochemical reactions; however, samples containing 40–50 vol % ionic liquid exhibit superior ionic properties and lower internal resistance compared to those containing less or more ionic liquids.

Intrabasement structures as structural templates for rifts: Insights from the Taranaki Basin, offshore New Zealand

NASA Astrophysics Data System (ADS)

Collanega, L.; Jackson, C. A. L.; Bell, R. E.; Lenhart, A.; Coleman, A. J.; Breda, A.; Massironi, M.

2017-12-01

Intrabasement structures are often envisaged to have acted as structural templates for normal fault growth in the overlying sedimentary cover during rifting (e.g. East African Rift; NE Brazilian Margin; Norwegian North Sea). However, in some settings, the geometry of rift-related faults is apparently unaffected by pre-existing basement fabric (Måløy Slope and Lofoten Ridge, offshore Norway). Understanding the nucleation and propagation of normal faults in the presence of basement structures may elucidate how and under what conditions basement fabric can exert an influence on rifting. Here, we investigate the 3D geometry of a series of normal faults and intrabasement structures from the Taranaki Basin, offshore New Zealand to understand how normal faults grow in the presence of basement heterogeneities. The Taranaki Basin is an ideal setting because the basement structures, related to the Mesozoic compressional tectonics, are shallow and well-imaged on 3D seismic reflection data, and the relatively thin and stratigraphically simple sedimentary cover is only affected by mild Pliocene extension. Our kinematic analysis highlights two classes of normal faults affecting different vertical intervals of the sedimentary cover. Deep faults, just above the basement, strike NW-SE to NE-SW, reflecting the trend of underlying intrabasement structures. In contrast, shallow faults strike according to the NE-SW to NNE-SSW Pliocene trend and are not generally affected by intrabasement structures at distances >500 m above the basement. Deep and shallow faults are only linked when they strike similarly, and are located above strong intrabasement reflections. We infer that cover deformation is significantly influenced by intrabasement structures within the 500 m interval above the crystalline basement, whereas shallower faults are optimally aligned to the Pliocene regional stress field. Since we do not observe an extensional reactivation of intrabasement structures during Pliocene rifting, we suspect that the key factor controlling cover fault nucleation and growth are local stress perturbations due to intrabasement structures. We conclude that intrabasement structures may provide a structural template for subsequent rift episodes, but only when these structures are proximal to newly forming faults.

The Discovery of a Potential Antimicrobial Agent: the Novel Compound Natural Medicinal Plant Fermentation Extracts against Candida albicans

NASA Astrophysics Data System (ADS)

Song, Mingzhu; Wang, Xirui; Mao, Canquan; Yao, Wei

2018-01-01

Natural medicinal plants and their extracts are important sources of antimicrobial drug development. In this study, we reported an ancient formula of Chinese folk medicine, the compound natural medicinal plant fermentation extracts (CNMPFE) for its antimicrobial effects. The effects and mechanisms of CNMPFE on C. albicans were studied by cell damage experiments including antimicrobial kinetics, fungal growth curve, alkaline phosphatase (AKP) activity, ultraviolet absorption, electric conductivity and the evaluation of cellular ultra microstructure. The results showed that the minimal inhibitory concentration and minimum fungicidal concentration of CNMPFE against C. albicans were 75% (vol/vol) and 80% (vol/vol) respectively. The inhibition of CNMPFE for C. albicans was dose and time dependent, based on increasing of the AKP activities and the ultraviolet absorptions and the electric conductivities of the fungal solutions, it may exert its antifungal properties by disrupting the structure of cell wall and the cell membrane integrity and their permeability, subsequently resulting in cell death. Taken together, these findings suggest that CNMPFE may be a promising drug candidate for the treatment of fungal infections skin diseases.

NLC Newsletter

Science.gov Websites

November 2003 Vol. 4 No. 10 - 11 September 2003 Vol. 4 No. 9 August 2003 Vol.4 No. 8 July 2003 Vol.4 No. 7 Vol. 3 No. 9 August 2002 Vol. 3 No. 8 July 2002 Vol. 3 No. 7 June 2002 Vol. 3 No. 6 May 2002 Vol. 3 No . 2 No.10 August 2001 Vol. 2 No. 4 March 2001 Vol. 2 No. 3 February 2001 Vol. 2 No. 2 January 2001 Vol

Characterisation of impacts on the environment of an idealised offshore wind farm foundation, under waves and the combination of waves and currents

NASA Astrophysics Data System (ADS)

García-Hermosa, Isabel; Abcha, Nizar; Brossard, Jérôme; Bennis, Anne-Claire; Ezersky, Alexander; Gross, Marcus; Iglesias, Gregorio; Magar, Vanesa; Miles, Jon; Mouazé, Dominique; Perret, Gaële; Pinon, Grégory; Rivier, Aurélie; Rogan, Charlie; Simmonds, David

2015-04-01

Offshore wind technology is currently the most widespread and advanced source of marine renewable energy. Offshore wind farms populate waters through the North Sea and the English Channel. The UK and French governments devised deadlines to achieve percentages of electricity from renewable sources by 2020, these deadlines and the direct translation of land based wind farm technology to the offshore environment resulted in the rapid expansion of the offshore wind energy. New wind farms have been designed with a larger number of masts and are moving from shallow offshore banks to deeper waters and in order to produce more power the diameters of monopoles masts are becoming larger to support larger turbines. The three-partner EU INTERREG funded project OFELIA (http://www.interreg-ofelia.eu/) aims to establish a cross-channel (between the UK and France) research collaboration to improve understanding of the environmental impacts of offshore wind farm foundations. The objective of the present study is to characterise changes in the hydrodynamics and sea bed in the vicinity of an offshore wind farm mast and in the wake area under wave and wave-current conditions corresponding to events in the French wind farm site of Courseulles-sur-mer (offshore of Lower Normandy, in the English Channel). Experiments were carried out in two laboratory facilities: a wave flume of 35 m long, 0.9 m wide and 1.2 m in depth with regular and irregular waves (García-Hermosa et al., 2014); and a wave and current flume of 17 m long, 0.5 m wide and 0.4 m depth with regular waves, currents from 180° to the waves and a mobile bed (Gunnoo et al., 2014). Flow velocity measurements were taken with an Acoustic Dopple Velocimeter (ADV) at various points around the cylinder and Particle Image Velocitmetry (PIV) techniques were applied to larger areas upstream and downstream of the cylinder. During the assessment of waves and currents' effects on the bed evolution were assessed using a laser and camera system photographing the bed (Marin & Ezersky, 2007, and Jarno-Druaux et al., 2004). Velocity fields, and flow structures around the cylinder at low KC numbers (KC~1) were characterised and parameters such as vorticity, turbulent kinetic energy and bed shear stresses derived where possible. During the experiments vortex structures with a horizontal axis were observed in the vicinity of the cylinder and the bed even at low KC. The Keulegan-Carpenter number (KC) is defined as: KC = UmT- D, where Um is the bottom orbital velocity, T the peak period and D the pile diameter. As part of the project, the findings from the experiments fed into a regional numerical modelling (Rivier et al., 2014) to improve parametrisation of the representation of the within-cell processes (local to the mast). References García-Hermosa, M. I., Brossard, J., Cohen, Z., Perret, G. (2014). Experimental characterisation of wave induced flow fields due to an offshore wind farm mast. First International Conference on Renewable Energies Offshore (RENEW) Lisbon, Portugal. November 2014. Gunnoo, H., Abcha, N., Mouazé, D., Ezersky, A., García-Hermosa, M. I. (2014). Laboratory simulation of resonance amplification of the hydrodynamic fields in the vicinity of wind farm masts. Proceedings of the First International Conference on Renewable Energies Offshore (RENEW) Lisbon, Portugal. November 2014. Jarno-Druaux, A., Brossard, J., Marin, F. (2004). Dynamical evolution of ripples in a wave channel, European Journal of Mechanics B/Fluids 23: 695-708. Marin, F. and Ezersky, A. B. (2007). Formation dynamics of sand bedforms under solitons and bound states of solitons in a wave flume used in resonant mode. European Journal of Mechanics - B/Fluids, Elsevier, 2008, 27 (3), pp.251-267. Rivier, A., Bennis, A.-C., Pinon, G., Gross, M., Magar, V. (2014). Regional numerical modelling of offshore monopile wind turbine impacts on hydrodynamics and sediment transport. Proceeding of the 1st International Conference on Renewable Energies Offshore (RENEW) Lisbon, Portugal. November 2014.

Main devices design of submarine oil-water separation system

NASA Astrophysics Data System (ADS)

Cai, Wen-Bin; Liu, Bo-Hong

2017-11-01

In the process of offshore oil production, in order to thoroughly separate oil from produced fluid, solve the environment problem caused by oily sewage, and improve the economic benefit of offshore drilling, from the perspective of new oil-water separation, a set of submarine oil-water separation devices were designed through adsorption and desorption mechanism of the polymer materials for crude oil in this paper. The paper introduces the basic structure of gas-solid separation device, periodic separation device and adsorption device, and proves the rationality and feasibility of this device.

Issues in offshore platform research - Part 1: Semi-submersibles

NASA Astrophysics Data System (ADS)

Sharma, R.; Kim, Tae-Wan; Sha, O. P.; Misra, S. C.

2010-09-01

Availability of economic and efficient energy resources is crucial to a nation's development. Because of their low cost and advancement in drilling and exploration technologies, oil and gas based energy systems are the most widely used energy source throughout the world. The inexpensive oil and gas based energy systems are used for everything, i.e., from transportation of goods and people to the harvesting of crops for food. As the energy demand continues to rise, there is strong need for inexpensive energy solutions. An offshore platform is a large structure that is used to house workers and machinery needed to drill wells in the ocean bed, extract oil and/or natural gas, process the produced fluids, and ship or pipe them to shore. Depending on the circumstances, the offshore platform can be fixed (to the ocean floor) or can consist of an artificial island or can float. Semi-submersibles are used for various purposes in offshore and marine engineering, e.g. crane vessels, drilling vessels, tourist vessels, production platforms and accommodation facilities, etc. The challenges of deepwater drilling have further motivated the researchers to design optimum choices for semi-submersibles for a chosen operating depth. In our series of eight papers, we discuss the design and production aspects of all the types of offshore platforms. In the present part I, we present an introduction and critical analysis of semi-submersibles.

Studying onshore-offshore fault linkages and landslides in Icy Bay and Taan Fjord to assess geohazards in Southeast Alaska

NASA Astrophysics Data System (ADS)

McCall, N.; Walton, M. A. L.; Gulick, S. P. S.; Haeussler, P. J.; Reece, R.; Saustrup, S.

2016-12-01

In southeast Alaska, the plate boundary where the Yakutat microplate collides with North America has produced large historical earthquakes (i.e., the Mw 8+ 1899 sequence). Despite the seismic potential, the possible source fault systems for these earthquakes have not been imaged with modern methods in Icy Bay. The offshore Pamplona Zone and its eastward onshore extension, the Malaspina Fault, may have played a role in the September 1899 earthquakes. Onshore and offshore mapping indicates that these structures likely connect offshore in Icy Bay. In August 2016 we collected high-resolution (300-1200 Hz) seismic reflection and multibeam bathymetry data to search for evidence of such faults beneath Icy Bay and Taan Fiord. If the Malaspina Fault is found to link with the Pamplona Zone, a rupture could trigger a tsunami impacting the populated regions in southeast Alaska. More recently, on October 17th 2015, nearby Taan Fjord experienced one of the largest non-volcanic landslides recorded in North America. Approximately 200 million metric tons spilled into Taan Fjord creating a tsunami with waves reaching 150m onshore. Using the new data, we are capable of imaging landslide and tsunami deposits in high-resolution. These data give new constraints for onshore-offshore fault systems, giving us new insights into the earthquake and tsunami hazard in southeast Alaska.

Effects of sea water on elongated duration of ground motion as well as variation in its amplitude for offshore earthquakes

NASA Astrophysics Data System (ADS)

Todoriki, Masaru; Furumura, Takashi; Maeda, Takuto

2017-01-01

We investigated the effects of sea water on the propagation of seismic waves using a 3-D finite-difference-method simulation of seismic wave propagation following offshore earthquakes. When using a 1-D layered structure, the simulation results showed strong S- to P-wave conversion at the sea bottom; accordingly, S-wave energy was dramatically decreased by the sea water layer. This sea water de-amplification effect had strong frequency dependence, therefore resembling a low-pass filter in which the cut-off frequency and damping coefficients were defined by the thickness of the sea water layer. The sea water also acted to elongate the duration of Rayleigh wave packet. The importance of the sea water layer in modelling offshore earthquakes was further demonstrated by a simulation using a realistic 3-D velocity structure model with and without sea water for a shallow (h = 14 km) outer-rise Nankai Trough event, the 2004 SE Off Kii Peninsula earthquake (Mw = 7.2). Synthetic seismograms generated by the model when sea water was included were in accordance with observed seismograms for long-term longer period motions, particularly those in the shape of Rayleigh waves.

Uncovering Offshore Financial Centers: Conduits and Sinks in the Global Corporate Ownership Network.

PubMed

Garcia-Bernardo, Javier; Fichtner, Jan; Takes, Frank W; Heemskerk, Eelke M

2017-07-24

Multinational corporations use highly complex structures of parents and subsidiaries to organize their operations and ownership. Offshore Financial Centers (OFCs) facilitate these structures through low taxation and lenient regulation, but are increasingly under scrutiny, for instance for enabling tax avoidance. Therefore, the identification of OFC jurisdictions has become a politicized and contested issue. We introduce a novel data-driven approach for identifying OFCs based on the global corporate ownership network, in which over 98 million firms (nodes) are connected through 71 million ownership relations. This granular firm-level network data uniquely allows identifying both sink-OFCs and conduit-OFCs. Sink-OFCs attract and retain foreign capital while conduit-OFCs are attractive intermediate destinations in the routing of international investments and enable the transfer of capital without taxation. We identify 24 sink-OFCs. In addition, a small set of five countries - the Netherlands, the United Kingdom, Ireland, Singapore and Switzerland - canalize the majority of corporate offshore investment as conduit-OFCs. Each conduit jurisdiction is specialized in a geographical area and there is significant specialization based on industrial sectors. Against the idea of OFCs as exotic small islands that cannot be regulated, we show that many sink and conduit-OFCs are highly developed countries.

40 CFR 227.21 - Uses considered.

Code of Federal Regulations, 2012 CFR

2012-07-01

... be affected by the proposed dumping, and a quantitative and qualitative evaluation made, where... development and offshore marine terminal or other structure development; and (l) Scientific research and study. ...

40 CFR 227.21 - Uses considered.

Code of Federal Regulations, 2011 CFR

2011-07-01

... be affected by the proposed dumping, and a quantitative and qualitative evaluation made, where... development and offshore marine terminal or other structure development; and (l) Scientific research and study. ...

40 CFR 227.21 - Uses considered.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be affected by the proposed dumping, and a quantitative and qualitative evaluation made, where... development and offshore marine terminal or other structure development; and (l) Scientific research and study. ...

40 CFR 227.21 - Uses considered.

Code of Federal Regulations, 2014 CFR

2014-07-01

... be affected by the proposed dumping, and a quantitative and qualitative evaluation made, where... development and offshore marine terminal or other structure development; and (l) Scientific research and study. ...

40 CFR 227.21 - Uses considered.

Code of Federal Regulations, 2013 CFR

2013-07-01

... be affected by the proposed dumping, and a quantitative and qualitative evaluation made, where... development and offshore marine terminal or other structure development; and (l) Scientific research and study. ...

Potential earthquake faults offshore Southern California, from the eastern Santa Barbara Channel south to Dana Point

USGS Publications Warehouse

Fisher, M.A.; Sorlien, C.C.; Sliter, R.W.

2009-01-01

Urban areas in Southern California are at risk from major earthquakes, not only quakes generated by long-recognized onshore faults but also ones that occur along poorly understood offshore faults. We summarize recent research findings concerning these lesser known faults. Research by the U.S. Geological Survey during the past five years indicates that these faults from the eastern Santa Barbara Channel south to Dana Point pose a potential earthquake threat. Historical seismicity in this area indicates that, in general, offshore faults can unleash earthquakes having at least moderate (M 5-6) magnitude. Estimating the earthquake hazard in Southern California is complicated by strain partitioning and by inheritance of structures from early tectonic episodes. The three main episodes are Mesozoic through early Miocene subduction, early Miocene crustal extension coeval with rotation of the Western Transverse Ranges, and Pliocene and younger transpression related to plate-boundary motion along the San Andreas Fault. Additional complication in the analysis of earthquake hazards derives from the partitioning of tectonic strain into strike-slip and thrust components along separate but kinematically related faults. The eastern Santa Barbara Basin is deformed by large active reverse and thrust faults, and this area appears to be underlain regionally by the north-dipping Channel Islands thrust fault. These faults could produce moderate to strong earthquakes and destructive tsunamis. On the Malibu coast, earthquakes along offshore faults could have left-lateral-oblique focal mechanisms, and the Santa Monica Mountains thrust fault, which underlies the oblique faults, could give rise to large (M ??7) earthquakes. Offshore faults near Santa Monica Bay and the San Pedro shelf are likely to produce both strike-slip and thrust earthquakes along northwest-striking faults. In all areas, transverse structures, such as lateral ramps and tear faults, which crosscut the main faults, could segment earthquake rupture zones. ?? 2009 The Geological Society of America.

Crustal structure of the southeastern Brazilian margin, Campos Basin, from aeromagnetic data: New kinematic constraints

NASA Astrophysics Data System (ADS)

Stanton, N.; Schmitt, R.; Galdeano, A.; Maia, M.; Mane, M.

2010-07-01

The continental and adjacent marginal features along southeast Brazil were investigated, focusing on the basement structural relationships between onshore and offshore provinces. Lateral and vertical variations in the magnetic anomalies provided a good correlation with the regional tectonic features. The sin-rift dykes and faults are associated with the magnetic lineaments and lie sub parallel to the Precambrian N45E-S45W basement structure of the Ribeira Belt, but orthogonally to the Cabo Frio Tectonic Domain (CFTD) basement, implying that: (1) the upper portion of the continental crust was widely affected by Mesozoic extensional deformation; and (2) tectonic features related to the process of break up of the Gondwana at the CFTD were form regardless of the preexisting structural basement orientation being controlled by the stress orientation during the rift phase. The deep crustal structure (5 km depth) is characterized by NE-SW magnetic "provinces" related to the Ribeira Belt tectonic units, while deep suture zones are defined by magnetic lows. The offshore Campos structural framework is N30E-S30W oriented and resulted from a main WNW-ESE direction of extension in Early Cretaceous. Transfer zones are represented by NW-SE and E-W oriented discontinuities. A slight difference in orientation between onshore (N45E) and offshore (N30E) structural systems seems to reflect a re-orientation of stress during rifting. We proposed a kinematical model to explain the structural evolution of this portion of the margin, characterized by polyphase rifting, associated with the rotation of the South American plate. The Campos Magnetic High (CMH), an important tectonic feature of the Campos Basin corresponds to a wide area of high crustal magnetization. The CMH wass interpreted as a magmatic feature, mafic to ultramafic in composition that extends down to 14 km depth and constitutes an evidence of intense crustal extension at 60 km from the coast.

An Advanced Flash Suppression Network Involving Alkali Salts

DTIC Science & Technology

1984-12-01

Potassium Tetroxide," J. Chem. -hys. Vol.4, p. 4 5 8 , 1936. A-8. JANAF Thermochemical Tables, 2nd Ed., D. R. Stull and H. Prophet, NSRDS-NBS-73, June 1971. A...34Structure of Potassium Tetroxide," J. Chem. Phys., Vol.4, p. 4 58 , 1936. A-8. JANAF Thlermochemical Tables, 2nd Ed., D. L Stull and H1. Prophet, NSRDS-NBS...A. Dean Washington, DC 20332 N. Chou P.O. Box 45 1Linden, NJ 07036 Kirtland AFB, NM 87117 Dirctor I Ford Aerospace and I N SIC Communications Corp

Testing for Structural Change by D-Methods in Switching Simultaneous Equations Models.

DTIC Science & Technology

1982-02-01

on ’Oaening Strate Raquiremets wad PP 225 Mili1tary Posture"). Chicago. il.. Septmer 2, 1976). Mengel . Marc. ’bciletons, Fluctuations, and tile Hopt...Telephocne Laoratories, Inc. Journal of tile Amrican Societ for Inforeeatlon Science, Vol. 3 N&. 6, pp. 366-370, Novowbr 1977). AD A04 425 PP 227 Mengel , Marc...Journal of Chemical Physics, Mengel , Marc S. end Thomas, Jons A., Jr., "Anelytical Vol. 69, ft. 8, Oct 1S, 1918). AD AD03 787 Methads In Search The"r," 86

Hydrodynamic trapping in the Cretaceous Nahr Umr lower sand of the North Area, Offshore Qatar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wells, P.R.A.

A hydrodynamic model is described to account for oil and gas occurrences in the Cretaceous of offshore Qatar, in the Arabian Gulf. Variable and inconsistent fluid levels and variable formation water potentials and salinities cannot be explained by combinations of stratigraphic and structural trapping. Indeed, there is no structural closure to the southwest of the oil and gas accumulations. The water-potential and salinity data and oil distribution are consistent with this model and indicate that a vigorous hydrodynamic system pervades the Cretaceous of the Arabian Gulf region. Extensive upward cross-formational discharge is taking place in the North Area. This cross-formationmore » water flow could be partly responsible for localized leaching and reservoir enhancement in the chalky limestones.« less

Effects of Second-Order Hydrodynamics on a Semisubmersible Floating Offshore Wind Turbine: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bayati, I.; Jonkman, J.; Robertson, A.

2014-07-01

The objective of this paper is to assess the second-order hydrodynamic effects on a semisubmersible floating offshore wind turbine. Second-order hydrodynamics induce loads and motions at the sum- and difference-frequencies of the incident waves. These effects have often been ignored in offshore wind analysis, under the assumption that they are significantly smaller than first-order effects. The sum- and difference-frequency loads can, however, excite eigenfrequencies of the system, leading to large oscillations that strain the mooring system or vibrations that cause fatigue damage to the structure. Observations of supposed second-order responses in wave-tank tests performed by the DeepCwind consortium at themore » MARIN offshore basin suggest that these effects might be more important than originally expected. These observations inspired interest in investigating how second-order excitation affects floating offshore wind turbines and whether second-order hydrodynamics should be included in offshore wind simulation tools like FAST in the future. In this work, the effects of second-order hydrodynamics on a floating semisubmersible offshore wind turbine are investigated. Because FAST is currently unable to account for second-order effects, a method to assess these effects was applied in which linearized properties of the floating wind system derived from FAST (including the 6x6 mass and stiffness matrices) are used by WAMIT to solve the first- and second-order hydrodynamics problems in the frequency domain. The method has been applied to the OC4-DeepCwind semisubmersible platform, supporting the NREL 5-MW baseline wind turbine. The loads and response of the system due to the second-order hydrodynamics are analysed and compared to first-order hydrodynamic loads and induced motions in the frequency domain. Further, the second-order loads and induced response data are compared to the loads and motions induced by aerodynamic loading as solved by FAST.« less

Southeast Offshore Storage Resource Assessment (SOSRA): Evaluation of CO2 Storage Potential on the Continental Shelf from North Carolina to Florida

NASA Astrophysics Data System (ADS)

Knapp, J. H.; Knapp, C. C.; Brantley, D.; Lakshmi, V.; Howard, S.

2016-12-01

The Southeast Offshore Storage Resource Assessment (SOSRA) project is part of a major new program, funded by the U.S. Department of Energy for the next two and a half years, to evaluate the Atlantic and Gulf of Mexico offshore margins of the United States for geologic storage capacity of CO2. Collaborating organizations include the Southern States Energy Board, Virginia Polytechnic Institute, University of South Carolina, Oklahoma State University, Virginia Department of Mines, Minerals, and Energy, South Carolina Geological Survey, and Geological Survey of Alabama. Team members from South Carolina are focused on the Atlantic offshore, from North Carolina to Florida. Geologic sequestration of CO2 is a major research focus globally, and requires robust knowledge of the porosity and permeability distribution in upper crustal sediments. Using legacy seismic reflection, refraction, and well data from a previous phase of offshore petroleum exploration on the Atlantic margin, we are analyzing the rock physics characteristics of the offshore Mesozoic and Cenozoic stratigraphy on a regional scale from North Carolina to Florida. Major features of the margin include the Carolina Trough, the Southeast Georgia Embayment, the Blake Plateau basin, and the Blake Outer Ridge. Previous studies indicate sediment accumulations on this margin may be as thick as 12-15 km. The study will apply a diverse suite of data analysis techniques designed to meet the goal of predicting storage capacity to within ±30%. Synthetic seismograms and checkshot surveys will be used to tie well and seismic data. Seismic interpretation and geophysical log analysis will employ leading-edge software technology and state-of-the art techniques for stratigraphic and structural interpretation and the definition of storage units and their physical and chemical properties. This approach will result in a robust characterization of offshore CO2 storage opportunities, as well as a volumetric analysis that is consistent with established procedures.

Structural health and prognostics management for offshore wind turbines :

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffith, Daniel; Resor, Brian Ray; White, Jonathan Randall

2012-12-01

Operations and maintenance costs for offshore wind plants are expected to be significantly higher than the current costs for onshore plants. One way in which these costs may be able to be reduced is through the use of a structural health and prognostic management system as part of a condition based maintenance paradigm with smart load management. To facilitate the creation of such a system a multiscale modeling approach has been developed to identify how the underlying physics of the system are affected by the presence of damage and how these changes manifest themselves in the operational response of amore » full turbine. The developed methodology was used to investigate the effects of a candidate blade damage feature, a trailing edge disbond, on a 5-MW offshore wind turbine and the measurements that demonstrated the highest sensitivity to the damage were the local pitching moments around the disbond. The multiscale method demonstrated that these changes were caused by a local decrease in the blades torsional stiffness due to the disbond, which also resulted in changes in the blades local strain field. Full turbine simulations were also used to demonstrate that derating the turbine power by as little as 5% could extend the fatigue life of a blade by as much as a factor of 3. The integration of the health monitoring information, conceptual repair cost versus damage size information, and this load management methodology provides an initial roadmap for reducing operations and maintenance costs for offshore wind farms while increasing turbine availability and overall profit.« less

Seismicity and active tectonics in the Alboran Sea, Western Mediterranean: Constraints from an offshore-onshore seismological network and swath bathymetry data

NASA Astrophysics Data System (ADS)

Grevemeyer, Ingo; Gràcia, Eulàlia; Villaseñor, Antonio; Leuchters, Wiebke; Watts, Anthony B.

2015-12-01

Seismicity and tectonic structure of the Alboran Sea were derived from a large amphibious seismological network deployed in the offshore basins and onshore in Spain and Morocco, an area where the convergence between the African and Eurasian plates causes distributed deformation. Crustal structure derived from local earthquake data suggests that the Alboran Sea is underlain by thinned continental crust with a mean thickness of about 20 km. During the 5 months of offshore network operation, a total of 229 local earthquakes were located within the Alboran Sea and neighboring areas. Earthquakes were generally crustal events, and in the offshore domain, most of them occurred at crustal levels of 2 to 15 km depth. Earthquakes in the Alboran Sea are poorly related to large-scale tectonic features and form a 20 to 40 km wide NNE-SSW trending belt of seismicity between Adra (Spain) and Al Hoceima (Morocco), supporting the case for a major left-lateral shear zone across the Alboran Sea. Such a shear zone is in accord with high-resolution bathymetric data and seismic reflection imaging, indicating a number of small active fault zones, some of which offset the seafloor, rather than supporting a well-defined discrete plate boundary fault. Moreover, a number of large faults known to be active as evidenced from bathymetry, seismic reflection, and paleoseismic data such as the Yusuf and Carboneras faults were seismically inactive. Earthquakes below the Western Alboran Basin occurred at 70 to 110 km depth and hence reflected intermediate depth seismicity related to subducted lithosphere.

Development of jacket platform tsunami risk rating system in waters offshore North Borneo

NASA Astrophysics Data System (ADS)

Lee, H. E.; Liew, M. S.; Mardi, N. H.; Na, K. L.; Toloue, Iraj; Wong, S. K.

2016-09-01

This work details the simulation of tsunami waves generated by seaquakes in the Manila Trench and their effect on fixed oil and gas jacket platforms in waters offshore North Borneo. For this study, a four-leg living quarter jacket platform located in a water depth of 63m is modelled in SACS v5.3. Malaysia has traditionally been perceived to be safe from the hazards of earthquakes and tsunamis. Local design practices tend to neglect tsunami waves and include no such provisions. In 2004, a 9.3 M w seaquake occurred off the northwest coast of Aceh, which generated tsunami waves that caused destruction in Malaysia totalling US 25 million and 68 deaths. This event prompted an awareness of the need to study the reliability of fixed offshore platforms scattered throughout Malaysian waters. In this paper, we present a review of research on the seismicity of the Manila Trench, which is perceived to be high risk for Southeast Asia. From the tsunami numerical model TUNA-M2, we extract computer-simulated tsunami waves at prescribed grid points in the vicinity of the platforms in the region. Using wave heights as input, we simulate the tsunami using SACS v5.3 structural analysis software of offshore platforms, which is widely accepted by the industry. We employ the nonlinear solitary wave theory in our tsunami loading calculations for the platforms, and formulate a platform-specific risk quantification system. We then perform an intensive structural sensitivity analysis and derive a corresponding platform-specific risk rating model.

Seismicity of the Earth 1900-2013 offshore British Columbia-southeastern Alaska and vicinity

USGS Publications Warehouse

Hayes, Gavin P.; Smoczyk, Gregory M.; Ooms, Jonathan G.; McNamara, Daniel E.; Furlong, Kevin P.; Benz, Harley M.; Villaseñor, Antonio

2014-01-01

The tectonics of the Pacific margin of North America between Vancouver Island and south-central Alaska are dominated by the northwest motion of the Pacific plate with respect to the North America plate at a velocity of approximately 50 mm/yr. In the south of this mapped region, convergence between the northern extent of the Juan de Fuca plate (also known as the Explorer microplate) and North America plate dominate. North from the Explorer, Pacific, and North America plate triple junction, Pacific:North America motion is accommodated along the ~650-km-long Queen Charlotte fault system. Offshore of Haida Gwaii and to the southwest, the obliquity of the Pacific:North America plate motion vector creates a transpressional regime, and a complex mixture of strike-slip and convergent (underthrusting) tectonics. North of the Haida Gwaii islands, plate motion is roughly parallel to the plate boundary, resulting in almost pure dextral strike-slip motion along the Queen Charlotte fault. To the north, the Queen Charlotte fault splits into multiple structures, continuing offshore of southwestern Alaska as the Fairweather fault, and branching east into the Chatham Strait and Denali faults through the interior of Alaska. The plate boundary north and west of the Fairweather fault ultimately continues as the Alaska-Aleutians subduction zone, where Pacific plate lithosphere subducts beneath the North America plate at the Aleutians Trench. The transition is complex, and involves intraplate structures such as the Transition fault. The Pacific margin offshore British Columbia is one of the most active seismic zones in North America and has hosted a number of large earthquakes historically.

Femtosecond laser-inscribed fiber Bragg gratings for strain monitoring in power cables of offshore wind turbines.

PubMed

Burgmeier, Jörg; Schippers, Wolfgang; Emde, Nico; Funken, Peter; Schade, Wolfgang

2011-05-01

A fiber Bragg grating sensor system used for monitoring the effects of strain on the power cable of an offshore wind turbine is presented. The Bragg grating structure was inscribed into coated nonphotosensitive standard telecommunication fibers using an IR femtosecond laser and the point-by-point writing technique. Because of the presence of the protective coating of the fiber, the mechanical stability of the resultant sensor device is better than that of a sensor consisting of a bare fiber. A system containing this sensing element was to our knowledge for the first time successfully installed and tested in an offshore wind turbine prototype (REpower 6M, REpower Systems, AG, Germany) in February 2010, near Ellhöft (Germany). The fabrication process of the fiber Bragg gratings, measurement results of the online monitoring, and a comparison between the sensor signal and commonly used sensing techniques are presented.

40 CFR 125.136 - As an owner or operator of a new offshore oil and gas extraction facility, what must I collect...

Code of Federal Regulations, 2012 CFR

2012-07-01

... you are a fixed facility and your cooling water intake structure is located in an estuary or tidal... waterbody flow information. If your cooling water intake structure is located in an estuary or tidal river...

40 CFR 125.136 - As an owner or operator of a new offshore oil and gas extraction facility, what must I collect...

Code of Federal Regulations, 2013 CFR

2013-07-01

... you are a fixed facility and your cooling water intake structure is located in an estuary or tidal... waterbody flow information. If your cooling water intake structure is located in an estuary or tidal river...

40 CFR 125.136 - As an owner or operator of a new offshore oil and gas extraction facility, what must I collect...

Code of Federal Regulations, 2014 CFR

2014-07-01

... you are a fixed facility and your cooling water intake structure is located in an estuary or tidal... waterbody flow information. If your cooling water intake structure is located in an estuary or tidal river...

MODU marine safety: Structural inspection and readiness surveys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, M.W.; Marucci, T.F.; Taft, D.G.

1987-11-01

Several years ago, Exxon instituted a survey of mobile offshore drilling units (MODU's) under contract to the corporation to evaluate structural integrity and readiness to respond properly to marine emergencies. This paper briefly describes results of the inspections and our on-going marine safety program. Industry activity is also highlighted.

Evidence for a strong sulfur-aromatic interaction derived from crystallographic data.

PubMed

Zauhar, R J; Colbert, C L; Morgan, R S; Welsh, W J

2000-03-01

We have uncovered new evidence for a significant interaction between divalent sulfur atoms and aromatic rings. Our study involves a statistical analysis of interatomic distances and other geometric descriptors derived from entries in the Cambridge Crystallographic Database (F. H. Allen and O. Kennard, Chem. Design Auto. News, 1993, Vol. 8, pp. 1 and 31-37). A set of descriptors was defined sufficient in number and type so as to elucidate completely the preferred geometry of interaction between six-membered aromatic carbon rings and divalent sulfurs for all crystal structures of nonmetal-bearing organic compounds present in the database. In order to test statistical significance, analogous probability distributions for the interaction of the moiety X-CH(2)-X with aromatic rings were computed, and taken a priori to correspond to the null hypothesis of no significant interaction. Tests of significance were carried our pairwise between probability distributions of sulfur-aromatic interaction descriptors and their CH(2)-aromatic analogues using the Smirnov-Kolmogorov nonparametric test (W. W. Daniel, Applied Nonparametric Statistics, Houghton-Mifflin: Boston, New York, 1978, pp. 276-286), and in all cases significance at the 99% confidence level or better was observed. Local maxima of the probability distributions were used to define a preferred geometry of interaction between the divalent sulfur moiety and the aromatic ring. Molecular mechanics studies were performed in an effort to better understand the physical basis of the interaction. This study confirms observations based on statistics of interaction of amino acids in protein crystal structures (R. S. Morgan, C. E. Tatsch, R. H. Gushard, J. M. McAdon, and P. K. Warme, International Journal of Peptide Protein Research, 1978, Vol. 11, pp. 209-217; R. S. Morgan and J. M. McAdon, International Journal of Peptide Protein Research, 1980, Vol. 15, pp. 177-180; K. S. C. Reid, P. F. Lindley, and J. M. Thornton, FEBS Letters, 1985, Vol. 190, pp. 209-213), as well as studies involving molecular mechanics (G. Nemethy and H. A. Scheraga, Biochemistry and Biophysics Research Communications, 1981, Vol. 98, pp. 482-487) and quantum chemical calculations (B. V. Cheney, M. W. Schulz, and J. Cheney, Biochimica Biophysica Acta, 1989, Vol. 996, pp.116-124; J. Pranata, Bioorganic Chemistry, 1997, Vol. 25, pp. 213-219)-all of which point to the possible importance of the sulfur-aromatic interaction. However, the preferred geometry of the interaction, as determined from our analysis of the small-molecule crystal data, differs significantly from that found by other approaches. Copyright 2000 John Wiley & Sons, Inc.

Subjective and objective comparisons of image quality between ultra-high-resolution CT and conventional area detector CT in phantoms and cadaveric human lungs.

PubMed

Yanagawa, Masahiro; Hata, Akinori; Honda, Osamu; Kikuchi, Noriko; Miyata, Tomo; Uranishi, Ayumi; Tsukagoshi, Shinsuke; Tomiyama, Noriyuki

2018-05-29

To compare the image quality of the lungs between ultra-high-resolution CT (U-HRCT) and conventional area detector CT (AD-CT) images. Image data of slit phantoms (0.35, 0.30, and 0.15 mm) and 11 cadaveric human lungs were acquired by both U-HRCT and AD-CT devices. U-HRCT images were obtained with three acquisition modes: normal mode (U-HRCT N : 896 channels, 0.5 mm × 80 rows; 512 matrix), super-high-resolution mode (U-HRCT SHR : 1792 channels, 0.25 mm × 160 rows; 1024 matrix), and volume mode (U-HRCT SHR-VOL : non-helical acquisition with U-HRCT SHR ). AD-CT images were obtained with the same conditions as U-HRCT N . Three independent observers scored normal anatomical structures (vessels and bronchi), abnormal CT findings (faint nodules, solid nodules, ground-glass opacity, consolidation, emphysema, interlobular septal thickening, intralobular reticular opacities, bronchovascular bundle thickening, bronchiectasis, and honeycombing), noise, artifacts, and overall image quality on a 3-point scale (1 = worst, 2 = equal, 3 = best) compared with U-HRCT N . Noise values were calculated quantitatively. U-HRCT could depict a 0.15-mm slit. Both U-HRCT SHR and U-HRCT SHR-VOL significantly improved visualization of normal anatomical structures and abnormal CT findings, except for intralobular reticular opacities and reduced artifacts, compared with AD-CT (p < 0.014). Visually, U-HRCT SHR-VOL has less noise than U-HRCT SHR and AD-CT (p < 0.00001). Quantitative noise values were significantly higher in the following order: U-HRCT SHR (mean, 30.41), U-HRCT SHR-VOL (26.84), AD-CT (16.03), and U-HRCT N (15.14) (p < 0.0001). U-HRCT SHR and U-HRCT SHR-VOL resulted in significantly higher overall image quality than AD-CT and were almost equal to U-HRCT N (p < 0.0001). Both U-HRCT SHR and U-HRCT SHR-VOL can provide higher image quality than AD-CT, while U-HRCT SHR-VOL was less noisy than U-HRCT SHR . • Ultra-high-resolution CT (U-HRCT) can improve spatial resolution. • U-HRCT can reduce streak and dark band artifacts. • U-HRCT can provide higher image quality than conventional area detector CT. • In U-HRCT, the volume mode is less noisy than the super-high-resolution mode. • U-HRCT may provide more detailed information about the lung anatomy and pathology.

The effect of oil-water-rock partitioning on the occurrence of alkylphenols in petroleum systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, P.; Larter, S.; Jones, M.

1997-05-01

Low molecular weight (C{sub 0}-C{sub 3}) alkylphenols are ubiquitous constituents of crude oils and formation waters of petroleum systems, and they represent legislatively monitored pollutants in produced oils and waters from offshore petroleum facilities. Their origin and the controls on their abundance are uncertain. Analysis of forty-four oils from various petroleum provinces, together with laboratory partitioning experiments, has provided further information on these controls. Although phenols are clearly partitioned between oil and water in petroleum systems, the consistency of most nondegraded petroleum phenol distributions (despite the apparent decrease of phenol concentrations in petroleums with increasing secondary migration distance) requires phenolmore » partitioning between petroleum, water, and solid phases-chiefly kerogen in the carrier bed. The retention of significant phenol concentrations in petroleums that have migrated tens of kilometres does indicate that petroleum typically only equilibrates with minor volumes of rock and associated waters. Laboratory experiments indicate that oils which have migrated approximately 25 km in the North Sea Tampen Spur through Jurassic sandstones may have equilibrated with less than 20 vol of rock and water, and possibly much less than 1 vol, depending on the sorbing phases within the rock (i.e., mineral or organic matter) and the wetting phase (oil or water). We conclude, supporting the hypothesis of Ioppolo-Armanios et al. (1995), that although ortho-substituted isomers dominate the phenol distributions of many petroleums, this reflects catalytic alkylation/isomerisation of unknown alkylphenol precursors in source rocks, rather than selective removal of meta- and para-substituted alkylphenol isomers from petroleum by water washing. 35 refs., 7 figs., 2 tabs.« less

Microstructure and mechanical properties of 2.5 vol. % TiBw/Ti6Al4V composites plates fabricated by hot-hydrostatic canned extrusion

NASA Astrophysics Data System (ADS)

Zhang, Wencong; Zhang, Lingjia; Feng, Yangju; Cui, Guorong; Chen, Wenzhen

2018-04-01

Plates of 2.5 vol. % TiB whisker-reinforced Ti6Al4V titanium matrix composites (TiBw/Ti64) with network structure were successfully fabricated by hot-hydrostatic extrusion with steel cup at 1100 °C. The dimensions of plates were about 150mm in length, 27mm in width and 2mm in thickness. After extrusion, the original equiaxed-network structure formed by TiB whiskers still existed, but was compressed in cross-section and stretched in longitudinal section and then the TiB whiskers were directional distribution along the extrusion direction. Furthermore, the mechanical properties results showed that the strength, hardness and ductility of the plates were significantly improved compared to as-sintered composites.

Crustal structure across the Brunswick Magnetic Anomaly in Southern Georgia

NASA Astrophysics Data System (ADS)

Lizarralde, D.; Shillington, D. J.; Harder, S. H.

2017-12-01

We will present results from Line 3 of the SUGAR experiment, a seismic refraction profile crossing the Brunswick Magnetic Anomaly (BMA) in southern Georgia. The BMA is a prominent, long-wavelength magnetic low that runs along the shelf offshore South Carolina and Georgia, turns inland near Brunswick and extends WNW toward Columbus GA. The source and significance of the BMA remain central elements of hypotheses for the construction of the SE U.S. continental lithosphere, including scenarios where the BMA marks the location of the Alleghany suture, where it represents a pre-existing suture within a peri-Gondwanan accreted terrane, and where the anomaly is related to Mesozoic rift-related tectono/magmatic processes. Deep-crustal reflectivity observed in multi-channel seismic images across the BMA proximal to the Laurentian margin near Columbus GA promoted the hypothesis that the BMA marks the location of the Alleghany suture. Results from an offshore refraction profile across the BMA along the Georgia shelf revealed a continuous, stratified, 4-km-thick layer in the upper crust beneath the post-rift unconformity with Vp=5.8 km/s interpreted as an undeformed Paleozoic metasedimentary section, inconsistent with an Alleghany suture, but also found an abrupt transition in mid-crustal velocity (6.18 north to 6.4 km/s south of BMA), consistent with preferential emplacement of Mesozoic magmatic additions or perhaps a pre-Alleghany suture. Line 3 of the SUGAR experiment is a relatively high-resolution crustal refraction line that included 11 shots and 700 seismic stations along a 110-km-long profile crossing normal to the BMA near Jesup GA. Preliminary results from Line 3 are similar to what is found offshore, with upper crustal velocities transitioning from 6.0 to 6.3 km/s across the BMA from N to S, with modest structural disruption related to the Kibbee Basin at the northern end of the line. These results are thus generally consistent with the ancient-suture hypothesis, though there is no corollary to the 5.8 km/s layer observed offshore. Further analyses will reveal upper-crustal structure in greater detail and also provide information on Moho structure across the BMA.

Marine fish community structure and habitat associations on the Canadian Beaufort shelf and slope

NASA Astrophysics Data System (ADS)

Majewski, Andrew R.; Atchison, Sheila; MacPhee, Shannon; Eert, Jane; Niemi, Andrea; Michel, Christine; Reist, James D.

2017-03-01

Marine fishes in the Canadian Beaufort Sea have complex interactions with habitats and prey, and occupy a pivotal position in the food web by transferring energy between lower- and upper-trophic levels, and also within and among habitats (e.g., benthic-pelagic coupling). The distributions, habitat associations, and community structure of most Beaufort Sea marine fishes, however, are unknown thus precluding effective regulatory management of emerging offshore industries in the region (e.g., hydrocarbon development, shipping, and fisheries). Between 2012 and 2014, Fisheries and Oceans Canada conducted the first baseline survey of offshore marine fishes, their habitats, and ecological relationships in the Canadian Beaufort Sea. Benthic trawling was conducted at 45 stations spanning 18-1001 m depths across shelf and slope habitats. Physical oceanographic variables (depth, salinity, temperature, oxygen), biological variables (benthic chlorophyll and integrated water-column chlorophyll) and sediment composition (grain size) were assessed as potential explanatory variables for fish community structure using a non-parametric statistical approach. Selected stations were re-sampled in 2013 and 2014 for a preliminary assessment of inter-annual variability in the fish community. Four distinct fish assemblages were delineated on the Canadian Beaufort Shelf and slope: 1) Nearshore-shelf: <50 m depth, 2) Offshore-shelf: >50 and ≤200 m depths, 3) Upper-slope: ≥200 and ≤500 m depths, and 4) Lower-slope: ≥500 m depths. Depth was the environmental variable that best explained fish community structure, and each species assemblage was spatially associated with distinct aspects of the vertical water mass profile. Significant differences in the fish community from east to west were not detected, and the species composition of the assemblages on the Canadian Beaufort Shelf have not changed substantially over the past decade. This community analysis provides a framework for testing hypotheses regarding the trophic dynamics and ecosystem roles of Beaufort Sea marine fishes, including biological linkages (i.e., fish movements and trophic interactions) among offshore habitats. Understanding regional-scale habitat associations will also provide context to identify potentially unique and/or sensitive habitats and fish community characteristics, thus aiding identification of ecologically and biologically significant areas, and to inform conservation efforts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karr, Dale G.; Yu, Bingbin; Sirnivas, Senu

To create long-term solutions for offshore wind turbines in a variety of environmental conditions, CAE tools are needed to model the design-driving loads that interact with an offshore wind turbine system during operation. This report describes our efforts in augmenting existing CAE tools used for offshore wind turbine analysis with a new module that can provide simulation capabilities for ice loading on the system. This augmentation was accomplished by creating an ice-loading module coupled to FAST8, the CAE tool maintained by the NREL for simulating land-based and offshore wind turbine dynamics. The new module includes both static and dynamic icemore » loading that can be applied during a dynamic simulation of the response of an offshore wind turbine. The ice forces can be prescribed, or influenced by the structure’s compliant response, or by the dynamics of both the structure and the ice floe. The new module covers ice failure modes of spalling, buckling, crushing, splitting, and bending. The supporting structure of wind turbines can be modeled as a vertical or sloping form at the waterline. The Inward Battered Guide Structure (IBGS) foundation designed by Keystone Engineering for the Great Lakes was used to study the ice models coupled to FAST8. The IBGS foundation ice loading simulations in FAST8 were compared to the baseline simulation case without ice loading. The ice conditions reflecting those from Lake Huron at Port Huron and Lake Michigan at North Manitou were studied under near rated wind speed of 12 m/s for the NREL 5-MW reference turbine. Simulations were performed on ice loading models 1 through 4 and ice model 6 with their respective sub-models. The purpose of ice model 5 is to investigate ice loading on sloping structures such as ice-cones on a monopile and is not suitable for multi-membered jacketed structures like the IBGS foundation. The key response parameters from the simulations, shear forces and moments from the tower base and IBGS foundation base, were compared. Ice models 1 and 6 do not significantly affect the tower fore-aft shear and moment. However, ice model 2 (dynamic analyses), model 3 (random ice loading), and model 4 (multiple ice failure zone loading) show increased effect on the tower fore-aft shear and moment with significant effect from ice model 3.1. In general ice loading creates large reaction forces and moments at the base of the IBGS foundation; the largest occurred in model 1.1 (steady creep ice indentation loading) followed by model 3.1 (random creep ice indentation loading). In general the power production from the ice loading cases had little deviation from the baseline case without ice loading. For ultimate limit state (ULS), ice model 1.1 ice and 3.1 appear to be the ice most critical models to consider at an early stage of design. Ice model 4 is an important tool for assessing structural fatigue.« less

Hydroxyapatite-based porous aggregates: physico-chemical nature, structure, texture and architecture.

PubMed

Fabbri, M; Celotti, G C; Ravaglioli, A

1995-02-01

At the request of medical teams from the maxillofacial sector, a highly porous ceramic support based on hydroxyapatite of around 70-80% porosity was produced with a pore size distribution similar to bone texture (< 10 microns, approximately 3 vol%; 10-150 microns, approximately 110 vol%; > 150 microns, approximately 86 vol%). The ceramic substrates were conceived not only as a fillers for bone cavities, but also for use as drug dispensers and as supports to host cells to produce particular therapeutic agents. A method is suggested to obtain a substrate of high porosity, exploiting the impregnation of spongy substrate with hydroxyapatite ceramic particles. X-ray and scanning electron microscopy analyses were carried out to evaluate the nature of the new ceramic support in comparison with the most common commercial product; pore size distribution and porosity were controlled to known hydroxyapatite ceramic architecture for the different possible uses.

Mechanical properties of particulate composites based on a body-centered-cubic Mg-Li alloy containing boron

NASA Technical Reports Server (NTRS)

Whalen, R. T.; Gonzalez-Doncel, G.; Robinson, S. L.; Sherby, O. D.

1989-01-01

The effect of substituting the Mg metal in Mg-B composites by a Mg-14 wt pct Li solid solution on the ductility of the resulting composite was investigated using elastic modulus measurements on the P/M composite material prepared with a dispersion of B particles (in a vol pct range of 0-30) in a matrix of Mg-14 wt pct Li-1.5 wt pct Al. It was found that the elastic modulus of the composites increased rapidly with increasing boron, with specific stiffness values reaching about two times that of most structural materials. The values of the compression and tensile strengths increased significantly with boron additions. Good tensile ductility was achieved at the level of 10 vol pct B. However, at 20 vol pct B, the Mg-Li composite exhibited only limited tensile ductility (about 2 percent total elongation).

Sparse Representation Based Classification with Structure Preserving Dimension Reduction

DTIC Science & Technology

2014-03-13

dictionary learning [39] used stochastic approximations to update dictionary with a large data set. Laplacian score dictionary ( LSD ) [58], which is based on...vol. 4. 2003. p. 864–7. 47. Shaw B, Jebara T. Structure preserving embedding. In: The 26th annual international conference on machine learning, ICML

Modeling of Lamb Waves and Application to Crack Identification

DTIC Science & Technology

2009-09-01

and Structures, vol. 13, pp. 621–630, 2004. [13] Seth S Kessler , S. Mark Spearing, and Constantinos Soutis, “Damage detection in composite materials...growth in metallic structures. Kessler et al. [13] presented part of an experimental and analytical survey of candidate methods for in-situ damage

Improved graph clustering

DTIC Science & Technology

2013-01-01

5, pp. 75–174, 2010. [2] J. Leskovec, K. J. Lang, A. Dasgupta, and M. W. Mahoney , “Statistical properties of community structure in large social and...2011. [14] R. R. Nadakuditi and M. Newman , “Graph spectra and the detectability of community structure in networks,” Phys. Rev. Lett., vol. 108, no

Post-CMOS Micromachining of Surface and Bulk Structures

DTIC Science & Technology

2002-05-06

Structures iii Acknowledgements I would like to thank my advisors, Professor Gary K. Fedder and Professor Dave W. Greve, for their continuing support...Donnelly, Plasma Chem. Plasma Process, vol. 1, pp. 37, 1981. [54] J. L. Mauer, J. S. Logan, L. B. Zielinski , and G. S. Schwartz, J. Vac. Sci. Technol

Fabrication and thermophysical property characterization of UN/U 3Si 2 composite fuel forms

DOE PAGES

White, Joshua Taylor; Travis, Austin William; Dunwoody, John Tyler; ...

2017-09-21

High uranium density composite fuels composed of UN and U 3Si 2 have been fabricated using a liquid phase sintering route at temperatures between 1873 K and 1973 K and spanning compositions of 10 vol% to 40 vol% U 3Si 2. Microstructural analysis and phase characterization revealed the formation of an U-Si-N phase of unknown structure. Microcracking was observed in the U-Si portion of the composite microstructure that likely originates from the mismatched coefficient of thermal expansion between the UN and U 3Si 2 leading to stresses on heating and cooling of the composite. Thermal expansion coefficient, thermal diffusivity, andmore » thermal conductivity were characterized for each of the compositions as a function of temperature to 1673 K. Hysteresis is observed in the thermal diffusivity for the 20 vol% through 40 vol% specimens between room temperature and 1273 K, which is attributed to the microcracking in the U-Si phase. Thermal conductivity of the composites was modeled using the MOOSE framework based on the collected microstructure data. In conclusion, the impact of irradiation on thermal conductivity was also simulated for this class of composite materials.« less

Fabrication and thermophysical property characterization of UN/U 3Si 2 composite fuel forms

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, Joshua Taylor; Travis, Austin William; Dunwoody, John Tyler

High uranium density composite fuels composed of UN and U 3Si 2 have been fabricated using a liquid phase sintering route at temperatures between 1873 K and 1973 K and spanning compositions of 10 vol% to 40 vol% U 3Si 2. Microstructural analysis and phase characterization revealed the formation of an U-Si-N phase of unknown structure. Microcracking was observed in the U-Si portion of the composite microstructure that likely originates from the mismatched coefficient of thermal expansion between the UN and U 3Si 2 leading to stresses on heating and cooling of the composite. Thermal expansion coefficient, thermal diffusivity, andmore » thermal conductivity were characterized for each of the compositions as a function of temperature to 1673 K. Hysteresis is observed in the thermal diffusivity for the 20 vol% through 40 vol% specimens between room temperature and 1273 K, which is attributed to the microcracking in the U-Si phase. Thermal conductivity of the composites was modeled using the MOOSE framework based on the collected microstructure data. In conclusion, the impact of irradiation on thermal conductivity was also simulated for this class of composite materials.« less

Reactivation of intrabasement structures during rifting: A case study from offshore southern Norway

NASA Astrophysics Data System (ADS)

Phillips, Thomas B.; Jackson, Christopher A.-L.; Bell, Rebecca E.; Duffy, Oliver B.; Fossen, Haakon

2016-10-01

Pre-existing structures within crystalline basement may exert a significant influence over the evolution of rifts. However, the exact manner in which these structures reactivate and thus their degree of influence over the overlying rift is poorly understood. Using borehole-constrained 2D and 3D seismic reflection data from offshore southern Norway we identify and constrain the three-dimensional geometry of a series of enigmatic intrabasement reflections. Through 1D waveform modelling and 3D mapping of these reflection packages, we correlate them to the onshore Caledonian thrust belt and Devonian shear zones. Based on the seismic-stratigraphic architecture of the post-basement succession, we identify several phases of reactivation of the intrabasement structures associated with multiple tectonic events. Reactivation preferentially occurs along relatively thick (c. 1 km), relatively steeply dipping (c. 30°) structures, with three main styles of interactions observed between them and overlying faults: i) faults exploiting intrabasement weaknesses represented by intra-shear zone mylonites; ii) faults that initiate within the hangingwall of the shear zones, inheriting their orientation and merging with said structure at depth; or iii) faults that initiate independently from and cross-cut intrabasement structures. We demonstrate that large-scale discrete shear zones act as a long-lived structural template for fault initiation during multiple phases of rifting.

Defense Threat Reduction Agency > Research > DTRIAC > DTRIAC Dispatch

Science.gov Websites

@mail.mil with your submissions. DTRIAC Dispatch - Vol 5, Issue 3 DTRIAC Dispatch - Vol 5, Issue 2 DTRIAC Dispatch - Vol 5, Issue 1 DTRIAC Dispatch - Vol 4, Issue 1 DTRIAC Dispatch - Vol 3, Issue 4 DTRIAC Dispatch - Vol 3, Issue 3 DTRIAC Dispatch - Vol 3, Issue 2 DTRIAC Dispatch - Vol 3, Issue 1 DTRIAC Dispatch - Vol

Pacific-North America plate boundary reorganization in response to a change in relative plate motion: Offshore Canada

NASA Astrophysics Data System (ADS)

Rohr, K. M. M.; Tryon, A. J.

2010-06-01

The transition from subduction in Cascadia to the transform Queen Charlotte fault along western Canada is often drawn as a subduction zone, yet recent studies of GPS and earthquake data from northern Vancouver Island are not consistent with that model. In this paper we synthesize seismic reflection and gravity interpretations with microseismicity data in order to test models of (1) microplate subduction and (2) reorganization of the preexisting strike-slip plate boundary. We focus on the critical region of outer Queen Charlotte Sound and the adjacent offshore. On much of the continental shelf, several million years of subsidence above thin crust are a counterindicator for subduction. An undated episode of compression uplifted the southernmost shelf, but subsidence patterns offshore show that recent subduction is unlikely to be responsible. Previously unremarked near-vertical faults and a mix of extensional and compressional faults offshore indicate that strike-slip faulting has been a significant mode of deformation. Seismicity in the last 18 years is dominantly strike-slip and shows large amounts of moment release on the Revere-Dellwood fault and its overlap with the Queen Charlotte fault. The relative plate motion between the Pacific and North American plates rotated clockwise ˜6 Ma and appears to have triggered formation of an evolving array of structures. We suggest that the paleo-Queen Charlotte fault which had defined this continental margin retreated northward as offshore distributed shear and the newly formed Revere Dellwood fault propagated to the northwest.

Virginia Offshore Wind Technology Advancement Project (VOWTAP) DOE EE0005985 Final Technical Report Rev 1a

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietryk, Steven

The primary purpose of the VOWTAP was to advance the offshore wind industry in the United States (U.S.) by demonstrating innovative technologies and process solutions that would establish offshore wind as a cost-effective renewable energy resource. The VOWTAP Team proposed to design, construct, and operate a 12 megawatt (MW) offshore wind facility located approximately 27 statute miles (mi) (24 nautical miles [nm], 43 kilometers [km]) off the coast of Virginia. The proposed Project would consist of two Alstom Haliade™ 150-6 MW turbines mounted on inward battered guide structures (IBGS), a 34.5-kilovolt (kV) alternating current (AC) submarine cable interconnecting the WTGsmore » (inter-array cable), a 34.5-kV AC submarine transmission cable (export cable), and a 34.5 kV underground cable (onshore interconnection cable) that would connect the Project with existing Dominion infrastructure located in Virginia Beach, Virginia (Figure 1). Interconnection with the existing Dominion infrastructure would also require an onshore switch cabinet, a fiber optic cable, and new interconnection station to be located entirely within the boundaries of the Camp Pendleton State Military Reservation (Camp Pendleton). The VOWTAP balanced technology innovation with commercial readiness such that turbine operations were anticipated to commence by 2018. Dominion, as the leaseholder of the Virginia Wind Energy Area (WEA), anticipated leveraging lessons learned through the VOWTAP, and applying them to future commercial-scale offshore wind development.« less

Tectonostratigraphy of the Passive Continental Margin Offshore Indus Pakistan

NASA Astrophysics Data System (ADS)

Aslam, K.; Khan, M.; Liu, Y.; Farid, A.

2017-12-01

The tectonic evolution and structural complexities are poorly understood in the passive continental margin of the Offshore Indus of Pakistan. In the present study, an attempt has been made to interpret the structural trends and seismic stratigraphic framework in relation to the tectonics of the region. Seismic reflection data revealed tectonically controlled, distinct episodes of normal faulting representing rifting at different ages and transpression in the Late Eocene time. This transpression has resulted in the reactivation of the Pre-Cambrian basement structures. The movement of these basement structures has considerably affected the younger sedimentary succession resulting in push up structures resembling anticlines. The structural growth of the push-up structures was computed. The most remarkable tectonic setting in the region is represented by the normal faulting and by the basement uplift which divides the rifting and transpression stages. Ten mappable seismic sequences have been identified on the seismic records. A Jurassic aged paleo-shelf has also been identified on all regional seismic profiles which is indicative of Indian-African Plates separation during the Jurassic time. Furthermore, the backstripping technique was applied which has been proved to be a powerful technique to quantify subsidence/uplift history of rift-type passive continental margins. The back strip curves suggest that transition from an extensional rifted margin to transpression occurred during Eocene time (50-30 Ma). The backstripping curves show uplift had happened in the area. We infer that the uplift has occurred due to the movement of basement structures by the transpression movements of Arabian and Indian Plates. The present study suggests that the structural styles and stratigraphy of the Offshore Indus Pakistan were significantly affected by the tectonic activities during the separation of Gondwanaland in the Mesozoic and northward movement of the Indian Plate, post-rifting, and sedimentations along its western margin during the Middle Cenozoic. The present comprehensive interpretation can help in understanding the structural complexities and stratigraphy associated with tectonics in other parts of the passive continental margins worldwide dominated by rifting and drifting tectonics.

The Junction of Hellenic and Cyprus Arcs: the Bey Daglari Lineament, Offshore Termination of the Antalya Basin

NASA Astrophysics Data System (ADS)

Gogacz, A.; Hall, J.; Cifci, G.; Yasar, D.; Kucuk, M.; Yaltirak, C.; Aksu, A.

2009-05-01

The Antalya Basin is one of a series of basins that sweep along the Cyprus Arc in the forearc region between the (formerly) volcanic Tauride Mountains on Turkey in the north and the subduction zone and associated suture between the African plate and the Aegean-Anatolian microplate in the eastern Mediterranean, south of Cyprus. Miocene contraction occurs widely on southwest verging thrusts. Pliocene-Quaternary structures vary from extension/transtension in the northeast, adjacent to the Turkish coastline, to transpression in the southwest, farther offshore. All these structures are truncated at the northwest end of the Antalya Basin by a broad zone of NNE-SSW-trending transverse structure that appears to represent a prolongation of the extreme easterly transform end of the Hellenic arc. Our mapping suggests that this broad zone links the Hellenic Arc with the Isparta Angle in southern Turkey, which we suggest is an earlier location of the junction of Hellenic and Cyprus Arcs: the junction migrated to the southwest over time, as the Hellenic Arc rolled back. The Turkish coastline turns from parallel to the Antalya Basin structures in the east to a N-S orientation, cutting across the trend of the Antalya Basin. The Antalya Complex and the Bey Dağları Mountains provide a spectacular backdrop to this edge of the offshore basin. Somewhere offshore lies the structural termination of the Antalya Basin. In 2001, we acquired around 400 km of high-resolution multi-channel seismic reflection data across the western end of the Antalya Basin to explore the nature of the termination, which we call the Bey Dağları lineament. We present a selection of the seismic profiles with interpretation of the nature and Neogene history of the lineament. Landward of the N-S-trending coastline, ophiolites of the Antalya Complex are exposed in a series of westerly-verging thrust slivers that extend to the carbonate sequences of the Bey Dağları Mountains. Our seismic data indicate that N-S trending west- and east-verging thrusts define a transpressional continental margin. The shelf is underlain by a prominent angular unconformity between overlying shallow-dipping Pliocene-Quaternary sediments and underlying, easterly- dipping ?Miocene sediments.

How large B-factors can be in protein crystal structures.

PubMed

Carugo, Oliviero

2018-02-23

Protein crystal structures are potentially over-interpreted since they are routinely refined without any restraint on the upper limit of atomic B-factors. Consequently, some of their atoms, undetected in the electron density maps, are allowed to reach extremely large B-factors, even above 100 square Angstroms, and their final positions are purely speculative and not based on any experimental evidence. A strategy to define B-factors upper limits is described here, based on the analysis of protein crystal structures deposited in the Protein Data Bank prior 2008, when the tendency to allow B-factor to arbitrary inflate was limited. This B-factor upper limit (B_max) is determined by extrapolating the relationship between crystal structure average B-factor and percentage of crystal volume occupied by solvent (pcVol) to pcVol =100%, when, ab absurdo, the crystal contains only liquid solvent, the structure of which is, by definition, undetectable in electron density maps. It is thus possible to highlight structures with average B-factors larger than B_max, which should be considered with caution by the users of the information deposited in the Protein Data Bank, in order to avoid scientifically deleterious over-interpretations.

30 CFR 250.903 - What records must I keep?

Code of Federal Regulations, 2013 CFR

2013-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Platforms and Structures General... steel brackets, deck stiffeners and secondary braces or beams would not generally be considered primary...

30 CFR 250.903 - What records must I keep?

Code of Federal Regulations, 2014 CFR

2014-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Platforms and Structures General... steel brackets, deck stiffeners and secondary braces or beams would not generally be considered primary...

30 CFR 250.903 - What records must I keep?

Code of Federal Regulations, 2012 CFR

2012-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Platforms and Structures General... steel brackets, deck stiffeners and secondary braces or beams would not generally be considered primary...

Offshore submarine storage facility for highly chilled liquified gases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, S.F.

1982-12-28

Improvements in an offshore platform and submarine storage facility for highly chilled liquified gas, such as liquified natural gas, are disclosed. The improved facility includes an elongated, vertically oriented submerged anchoring frame to which one or more insulated storage tanks are moveably mounted so they can be positioned at a selected depth in the water. The double piston tank is constructed with improved seals to transfer ambient water pressure of the selected depth to the cryogenic liquified gas without intermixture. This transferred pressure at the depth selected aids in maintaining the liquified state of the stored liquified gas. Structural improvementsmore » to the tank facilitating ballasting, locking the double piston cylinders together and further facilitating surface access to the tank for inspection, repairs and removal, and structural improvements to the platform are disclosed.« less

Structure, stratigraphy and petroleum geology of the south east Nam Con Son Basin, offshore Vietnam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fraser, A.J.; Matthews, S.J.; Lowe, S.

1996-12-31

Recent exploration of the south east Nam Con Son Basin, offshore Vietnam, by BP in alliance with Statoil has involved acquisition of new seismic and well data. These new data have allowed re-evaluation of the tectono-stratigraphic development and petroleum geology, and have provided additional constraints on the regional tectonic evolution. The offshore Vietnamese basins have evolved in response to the complex relative motions of Indochina, Peninsular Malaysia, Borneo and the South China Sea during the Cenozoic. On the regional scale these motions have been accommodated by strike-slip fault development, rifting and contraction. In the Nam Con Son Basin these motionsmore » have interacted in different ways from the Palaeogene to recent. Two rifting episodes are recognized; a Palaeogene phase dominated by E-W trending extensional faults, and a Miocene phase dominated by N-S to NE-SW trending faults. The structural evolution is complicated by a pulse of mild contraction during the Middle Miocene. The sedimentary fill of the basin evolves from continental fluvio-lacustrine in the Palaeogene through to fully marine following the second phase of rifting in the Miocene. This pulsed structural and stratigraphic evolution has resulted in basinwide deposition of source, reservoir and seal facies, and produced a variety of potential trapping styles. This paper describes the hydrocarbon habitat of the south east Nam Con Son Basin within the context of the regional tectono-stratigraphic model.« less

Structure, stratigraphy and petroleum geology of the south east Nam Con Son Basin, offshore Vietnam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fraser, A.J.; Matthews, S.J.; Lowe, S.

1996-01-01

Recent exploration of the south east Nam Con Son Basin, offshore Vietnam, by BP in alliance with Statoil has involved acquisition of new seismic and well data. These new data have allowed re-evaluation of the tectono-stratigraphic development and petroleum geology, and have provided additional constraints on the regional tectonic evolution. The offshore Vietnamese basins have evolved in response to the complex relative motions of Indochina, Peninsular Malaysia, Borneo and the South China Sea during the Cenozoic. On the regional scale these motions have been accommodated by strike-slip fault development, rifting and contraction. In the Nam Con Son Basin these motionsmore » have interacted in different ways from the Palaeogene to recent. Two rifting episodes are recognized; a Palaeogene phase dominated by E-W trending extensional faults, and a Miocene phase dominated by N-S to NE-SW trending faults. The structural evolution is complicated by a pulse of mild contraction during the Middle Miocene. The sedimentary fill of the basin evolves from continental fluvio-lacustrine in the Palaeogene through to fully marine following the second phase of rifting in the Miocene. This pulsed structural and stratigraphic evolution has resulted in basinwide deposition of source, reservoir and seal facies, and produced a variety of potential trapping styles. This paper describes the hydrocarbon habitat of the south east Nam Con Son Basin within the context of the regional tectono-stratigraphic model.« less

East Cameron Block 270, offshore Louisiana: a Pleistocene field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holland, D.S.; Sutley, C.E.; Berlitz, R.E.

1976-01-01

Exploration of the Plio-Pleistocene in the Gulf of Mexico since 1970 has led to the discovery of significant hydrocarbon reserves. One of the better gas fields found to date has been the East Cameron Block 270 field, offshore Louisiana. Utilization of a coordinated exploitation plan with Schlumberger Offshore Services has allowed Pennzoil Co., as operator, to develop and put the Block 270 field on production in minimum time. The structure at Block 270 field is a north-south-trending, faulted nose at 6000 ft (1825 m). At the depth of the ''G'' sandstone (8700 ft or 2650 m), the structure is closed;more » it is elongated north-south and dips in all directions from the Block 270 area. Closure is the result of contemporaneous growth of the east-bounding regional fault. Structural and stratigraphic interpretations from dipmeters were used to determine the most favorable offset locations. The producing zones consist of various combinations of bar-like, channel-like, and distributary-front sandstones. The sediment source for most of the producing zones was southwest of the area, except for two zones which derived their sediments from the north through a system of channels paralleling the east-bounding fault. Computed logs were used to convert conventional logging measurements into a more readily usable form for evaluation. The computed results were used for reserve calculations, reservoir-quality determinations, and confirmation of depositional environments as determined from other sources.« less

76 FR 12070 - Incidental Taking of Marine Mammals; Taking of Marine Mammals Incidental to the Explosive Removal...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-04

... Energy's EROS operations in 2010: Marine mammals Biological impacts Company Structure Dates sighted... Taking of Marine Mammals; Taking of Marine Mammals Incidental to the Explosive Removal of Offshore Structures in the Gulf of Mexico AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and...

30 CFR 250.901 - What industry standards must your platform meet?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Structures for Hurricane Conditions, (as incorporated by reference in § 250.198); (5) API Bulletin 2INT-EX, Interim Guidance for Assessment of Existing Offshore Structures for Hurricane Conditions, (as incorporated by reference in § 250.198); (6) API Bulletin 2INT-MET, Interim Guidance on Hurricane Conditions in...

30 CFR 250.901 - What industry standards must your platform meet?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Structures for Hurricane Conditions, (as incorporated by reference in § 250.198); (5) API Bulletin 2INT-EX, Interim Guidance for Assessment of Existing Offshore Structures for Hurricane Conditions, (as incorporated by reference in § 250.198); (6) API Bulletin 2INT-MET, Interim Guidance on Hurricane Conditions in...

30 CFR 250.901 - What industry standards must your platform meet?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Structures for Hurricane Conditions, (as incorporated by reference in § 250.198); (5) API Bulletin 2INT-EX, Interim Guidance for Assessment of Existing Offshore Structures for Hurricane Conditions, (as incorporated by reference in § 250.198); (6) API Bulletin 2INT-MET, Interim Guidance on Hurricane Conditions in...

Paleostress Reconstruction from 3D seismic, Natural Fracture and Calcite Twin Analyses: Structural Insights into the Otway Basin, Australia

NASA Astrophysics Data System (ADS)

Burgin, Hugo; Amrouch, Khalid; Holford, Simon

2017-04-01

The Otway Basin, Australia, is of particular interest due to its significance as an Australian hydrocarbon producing province and a major global CO2 burial project. Structural data was collected in the form of natural fractures from wellbore image logs and outcrop in addition to calcite twin analyses, within formations from the mid cretaceous from both on and offshore. Evidence for four structural events within the study area have been identified including NE-SW and NW-SE orientated extension, in addition to a NW-SE compressive event. Natural fracture data also reveals a previously "un-detected" NE-SW compression within the Otway Basin. This study presents the first investigation of paleostress environments within the region from micro, meso and macro scale tectonic data in both onshore and offshore in addition to the first quantification of differential paleostresses. This work highlights the importance of a comprehensive understanding of four dimensional stress evolution within the sedimentary basins of Australia's southern margin.

Decommissioning of offshore oil and gas facilities: a comparative assessment of different scenarios.

PubMed

Ekins, Paul; Vanner, Robin; Firebrace, James

2006-06-01

A material and energy flow analysis, with corresponding financial flows, was carried out for different decommissioning scenarios for the different elements of an offshore oil and gas structure. A comparative assessment was made of the non-financial (especially environmental) outcomes of the different scenarios, with the reference scenario being to leave all structures in situ, while other scenarios envisaged leaving them on the seabed or removing them to shore for recycling and disposal. The costs of each scenario, when compared with the reference scenario, give an implicit valuation of the non-financial outcomes (e.g. environmental improvements), should that scenario be adopted by society. The paper concludes that it is not clear that the removal of the topsides and jackets of large steel structures to shore, as currently required by regulations, is environmentally justified; that concrete structures should certainly be left in place; and that leaving footings, cuttings and pipelines in place, with subsequent monitoring, would also be justified unless very large values were placed by society on a clear seabed and trawling access.

Damage to offshore infrastructure in the Gulf of Mexico by hurricanes Katrina and Rita

NASA Astrophysics Data System (ADS)

Cruz, A. M.; Krausmann, E.

2009-04-01

The damage inflicted by hurricanes Katrina and Rita to the Gulf-of-Mexico's (GoM) oil and gas production, both onshore and offshore, has shown the proneness of industry to Natech accidents (natural hazard-triggered hazardous-materials releases). In order to contribute towards a better understanding of Natech events, we assessed the damage to and hazardous-materials releases from offshore oil and natural-gas platforms and pipelines induced by hurricanes Katrina and Rita. Data was obtained through a review of published literature and interviews with government officials and industry representatives from the affected region. We also reviewed over 60,000 records of reported hazardous-materials releases from the National Response Center's (NRC) database to identify and analyze the hazardous-materials releases directly attributed to offshore oil and gas platforms and pipelines affected by the two hurricanes. Our results show that hurricanes Katrina and Rita destroyed at least 113 platforms, and severely damaged at least 53 others. Sixty percent of the facilities destroyed were built 30 years ago or more prior to the adoption of the more stringent design standards that went into effect after 1977. The storms also destroyed 5 drilling rigs and severely damaged 19 mobile offshore drilling units (MODUs). Some 19 MODUs lost their moorings and became adrift during the storms which not only posed a danger to existing facilities but the dragging anchors also damaged pipelines and other infrastructure. Structural damage to platforms included toppling of sections, and tilting or leaning of platforms. Possible causes for failure of structural and non-structural components of platforms included loading caused by wave inundation of the deck. Failure of rigs attached to platforms was also observed resulting in significant damage to the platform or adjacent infrastructure, as well as damage to equipment, living quarters and helipads. The failures are attributable to tie-down components and occurred on both fixed and floating platforms. The total number of pipelines damaged by Hurricanes Katrina and Rita as of May 1, 2006, was 457. Pipeline damage was mostly caused by damage or failure of the host platform or its development and production piping, the impact of dragging and displaced objects, and pipeline interaction at a crossing. Damage to pipelines was a major contributing factor in delaying start up of offshore oil and gas production. During our analysis of the NRC database we identified 611 reported hazardous-materials releases directly attributed to offshore platforms and pipelines affected by the two hurricanes. There were twice as many releases during Hurricane Katrina than during Rita; 80% or more of the releases reported in the NRC database occurred from platforms. Our analysis suggests that the majority of releases were petroleum products, such as crude oil and condensate, followed by natural gas. In both Katrina and Rita, releases were more likely in the front, right quadrant of the storm. Storm-surge values were highest closer to the coastline. This may help explain the higher number of releases in shallow waters. The higher number of hazardous-materials releases from platforms during Katrina may partly be attributed to the higher wind speeds for this storm as it approached land.

The marine geology of the eastern Santa Barbara Channel, with particular emphasis on the ground water basins offshore from the Oxnard Plain, Southern California

USGS Publications Warehouse

Greene, H. Gary; Wolf, Stephen C.; Blom, Ken G.

1978-01-01

Marine geophysical investigations provide new data concerning the stratigraphy, tectonic and sedimentary history, and the ground water geology of the southeastern Santa Barbara Channel region. The offshore stratigraphy identified in seismic reflection profiles includes a succession of Neogene to Quaternary strata. The middle Miocene Conejo volcanics form an acoustical basement and the overlying late Cenozoic sedimentary rocks attain a thickness greater than 2,500 m. These sedimentary deposits fill a structurally controlled, physiographic and depositional depression called the Ventura Basin. Structure consists generally of a gently folded, east-trending Tertiary synclinorium bordered on the north by a regional thrust fault and on the south by a steep asymmetrical anticlinal ridge. Most structures show evidence of north-south compression that occurred during early Pleistocene time. Three well-defined unconformities represent widespread erosion in late Miocene, early to middle Pleistocene, and late Pleistocene time. The boundaries of Miocene, Pliocene, and lower Pleistocene strata continue uninterrupted eastward along the southern part of Santa Barbara basin to Hueneme Canyon, where they turn northeast and can be traced to the coast near Port Hueneme. These limits probably represent the south edge of the Santa Barbara basin during Pliocene and Pleistocene time. Fresh water-bearing materials of the Oxnard plain are unconsolidated Quaternary sediment laid down on more consolidated Tertiary rocks. Offshore, the total fresh water-bearing materials distinguished in the seismic reflection profiles attain a thickness of about 356 m and have an areal extent of over 760 km2. Strata that contain the offshore continuation of the five major on-land aquifers (Grimes Canyon, Fox Canyon, Hueneme, Mugu, and Oxnard aquifers) are identified in the seismic reflection profiles. These strata make up the two offshore ground-water basins, the Mound and Oxnard plain ground-water basins, which are separated by the east-west trending Oak Ridge fault. Possible entrance areas for salt water intrusion into fresh water aquifers are found along the walls of the submarine canyons and along the northern slopes of Santa Barbara and Santa Monica basins. Hueneme and Mugu aquifers are probably exposed locally in all five submarine canyons of the Oxnard offshore area and may also crop out along the upper northern slope of Santa Monica basin. In all of these areas, salt water readily intrudes the aquifers. A salinity-temperature-depth study made in April, 1971, does not indicate any great dilution of surface ocean water by fresh water that could be 'leaking' from the exposed aquifers along the walls of Hueneme Canyon and the landward slope of Santa Barbara Channel. Earthquakes in the vicinity of the Oxnard plain suggest that the region is seismically active. Epicenters are widely dispersed over the region. No distinct trend or alignment of earthquake epicenters occurs near the trace of any of the faults, although many epicenters are scattered around the Oak Ridge zone of deformation in the northern part of the region. The largest magnitude earthquake recorded in the area was a magnitude 5.7 that occurred on February 21, 1973, offshore of Point Mugu, south of the Oxnard plain.

Structure and Electrochemistry of Copper Fluoride Nanocomposites Utilizing Mixed Conducting Matrices

DTIC Science & Technology

2007-01-01

similar to the conversion reaction of the metal fluoride. Attractive materials such as V2O5 , MoS2, and MoO3-δ can be utilized. Examples of metal...fluorides enabled by these MCM matrices are nanocomposites of FeF3 ( V2O5 ),2 BiF3 (MoS2),15 and as discussed herein, CuF2 (MoO3). In all cases, the...filled dry box using Whatman GF/D glass fiber separators saturated with 1M LiPF6 in 1:1 vol/vol ethylene carbonate:dimethyl carbonate elec- trolyte

Program for establishing long-time flight service performance of composite materials in the center wing structure of C-130 aircraft. Phase 3: Fabrication

NASA Technical Reports Server (NTRS)

Harvill, W. E.; Kays, A. O.

1974-01-01

The manufacturing plan for three C-130 aircraft center wing box test articles, selectively reinforced with boron-epoxy composites, is outlined for the following tasks: (1) tooling; (2) metal parts fabrication: (3) reinforcing laminate fabrication; (4) laminate-to-metal parts bonding; and (5) wing box assembly. The criteria used for reliability and quality assurance are discussed, and several solutions to specific manufacturing problems encountered during fabrication are given. For Vol. 1, see N73-13011; for Vol. 2, see N73-22929.

High loading uranium fuel plate

DOEpatents

Wiencek, Thomas C.; Domagala, Robert F.; Thresh, Henry R.

1990-01-01

Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pair of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat having a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process.

Helical piles: an innovative foundation design option for offshore wind turbines.

PubMed

Byrne, B W; Houlsby, G T

2015-02-28

Offshore wind turbines play a key part in the renewable energy strategy in the UK and Europe as well as in other parts of the world (for example, China). The majority of current developments, certainly in UK waters, have taken place in relatively shallow water and close to shore. This limits the scale of the engineering to relatively simple structures, such as those using monopile foundations, and these have been the most common design to date, in UK waters. However, as larger turbines are designed, or they are placed in deeper water, it will be necessary to use multi-footing structures such as tripods or jackets. For these designs, the tension on the upwind footing becomes the critical design condition. Driven pile foundations could be used, as could suction-installed foundations. However, in this paper, we present another concept-the use of helical pile foundations. These foundations are routinely applied onshore where large tension capacities are required. However, for use offshore, a significant upscaling of the technology will be needed, particularly of the equipment required for installation of the piles. A clear understanding of the relevant geotechnical engineering will be needed if this upscaling is to be successful. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Seismic definition of Lower Cretaceous delta, south Whale subbasin, offshore Newfoundland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jayasinghe, N.R.; Stokes, R.E.

1986-05-01

Recognition of stratigraphic traps in areas where previous prospects were structural is a trend attributable partly to the availability of new, high-quality seismic data. In the South Whale subbasin, offshore Newfoundland, Canada, such a change in exploration philosophy is presently being evaluated. Exploratory drilling offshore eastern Canada began in 1966 in the South Whale subbasin. By the end of 1973, 13 wells were drilled in this subbasin; however, lack of success discouraged further drilling. These wells evaluated large, salt-related structures, well defined by seismic data. Although an adequate reservoir was encountered in a number of these wells, faulting associated withmore » halokinesis may have resulted in petroleum migration out of the reservoir. Interpretation of recently acquired high-quality seismic data indicate a delta in the Lower Cretaceous Missisauga Formation in the study area. Seismic dip sections across the delta show a shingled progradation pattern suggesting a wave-dominated depositional environment. The delta comprises approximately 400 km/sup 2/, with closure in the eastern half. Data from wells in the area indicate that adequate source and sealing beds could be present. Furthermore, rocks of similar age in the nearby Avalon basin contain significant petroleum accumulations, the most notable being within the Hibernia oil field.« less

Abundance and Genetic Diversity of Aerobic Anoxygenic Phototrophic Bacteria of Coastal Regions of the Pacific Ocean

PubMed Central

Ritchie, Anna E.

2012-01-01

Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic microbes that are found in a broad range of aquatic environments. Although potentially significant to the microbial ecology and biogeochemistry of marine ecosystems, their abundance and genetic diversity and the environmental variables that regulate these properties are poorly understood. Using samples along nearshore/offshore transects from five disparate islands in the Pacific Ocean (Oahu, Molokai, Futuna, Aniwa, and Lord Howe) and off California, we show that AAP bacteria, as quantified by the pufM gene biomarker, are most abundant near shore and in areas with high chlorophyll or Synechococcus abundance. These AAP bacterial populations are genetically diverse, with most members belonging to the alpha- or gammaproteobacterial groups and with subclades that are associated with specific environmental variables. The genetic diversity of AAP bacteria is structured along the nearshore/offshore transects in relation to environmental variables, and uncultured pufM gene libraries suggest that nearshore communities are distinct from those offshore. AAP bacterial communities are also genetically distinct between islands, such that the stations that are most distantly separated are the most genetically distinct. Together, these results demonstrate that environmental variables regulate both the abundance and diversity of AAP bacteria but that endemism may also be a contributing factor in structuring these communities. PMID:22307290

The revised HSE fatigue guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stacey, A.; Sharp, J.V.

1995-12-31

Fatigue cracking has been a principal cause of damage to North Sea structures and consequently considerable attention has been given to the development of guidance for the prediction of fatigue performance. The fatigue guidance of the Offshore Safety Division of the Health and Safety Executive (HSE) was recently revised and published, following a significant offshore industry review in the period 1987 to 1990, and is based on the results of a considerable amount of research and development work on the fatigue behavior of welded tubular and plated joints. As a result of this review, the revised fatigue guidance incorporates severalmore » new clauses and recommendations. The revised recommendations apply to joint classification, basic design S-N curves for welded joints and cast or forged steel components, the thickness effect, the effects of environment and the treatment of low and high stress ranges. Additionally, a new appendix on the derivation of stress concentration factors is included. The new clauses cover high strength steels, bolts and threaded connectors, moorings, repaired joints and the use of fracture mechanics analysis. This paper presents an overview of the revisions to the fatigue guidance, the associated background technical information and aspects of the fatigue behavior of offshore structures which are considered to require further investigation. 67 refs., 7 figs., 8 tabs.« less

Silver Flakes and Silver Dendrites for Hybrid Electrically Conductive Adhesives with Enhanced Conductivity

NASA Astrophysics Data System (ADS)

Ma, Hongru; Li, Zhuo; Tian, Xun; Yan, Shaocun; Li, Zhe; Guo, Xuhong; Ma, Yanqing; Ma, Lei

2018-03-01

Silver dendrites were prepared by a facile replacement reaction between silver nitrate and zinc microparticles of 20 μm in size. The influence of reactant molar ratio, reaction solution volume, silver nitrate concentration, and reaction time on the morphology of dendrites was investigated systematically. It was found that uniform tree-like silver structures are synthesized under the optimal conditions. Their structure can be described as a trunk, symmetrical branches, and leaves, which length scales of 5-10, 1-2 μm, and 100-300 nm, respectively. All features were systematically characterized by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, and x-ray powder diffraction. A hybrid fillers system using silver flakes and dendrites as electrically conductive adhesives (ECAs) exhibited excellent overall performance. This good conductivity can be attributed mainly to the synergy between the silver microflakes (5-20 μm sized irregular sheet structures) and dendrites, allowing more conductive pathways to be formed between the fillers. In order to further optimize the overall electrical conductivity, various mixtures of silver microflakes and silver dendrites were tested in ECAs, with results indicating that the highest conductivity was shown when the amounts of silver microflakes, silver dendrites and the polymer matrix were 69.4 wt.% (20.82 vol.%), 0.6 wt.% (0.18 vol.%), and 30.0 wt.% (79.00 vol.%), respectively. The corresponding mass ratio of silver flakes to silver dendrites was 347:3. The resistivity of ECAs reached as low as 1.7 × 10-4 Ω cm.

Geometry and active tectonics of the Los Osos-Hosgri Fault Intersection in Estero Bay, CA: Reconciling seismicity patterns with near-surface geology

NASA Astrophysics Data System (ADS)

Watt, J. T.; Hardebeck, J.; Johnson, S. Y.; Kluesner, J.

2016-12-01

Characterizing active structures within structurally complex fault intersections is essential for unraveling the deformational history and for assessing the importance of fault intersections in regional earthquake hazard assessments. We employ an integrative, multi-scale geophysical approach to describe the 3D geometry and active tectonics of the offshore Los Osos fault (LOF) in Estero Bay, California. The shallow structure of the LOF, as imaged with multibeam and high-resolution seismic-reflection data, reveals a complex west-diverging zone of active faulting that bends into and joins the Hosgri fault. The down-dip geometry of the LOF as revealed by gravity, magnetic, and industry multi-channel seismic data, is vertical to steeply-dipping and varies along strike. As the LOF extends offshore, it is characterized by SW-side-up motion on a series of W-NW trending, steeply SW-dipping reverse faults. The LOF bends to the north ( 23°) as it approaches the Hosgri fault and dips steeply to the NE along a magnetic basement block. Inversion of earthquake focal mechanisms within Estero Bay yields maximum compressive stress axes that are near-horizontal and trend approximately N15E. This trend is consistent with dextral strike-slip faulting along NW-SE trending structures such as the Hosgri fault and northern LOF, and oblique dip-slip motion along the W-NW trending section of the LOF. Notably, NW-SE trending structures illuminated by seismicity in Estero Bay coincide with, but also appear to cross-cut, LOF structures imaged in the near-surface. We suggest this apparent disconnect reflects ongoing fault reorganization at a dynamic and inherently unstable fault intersection, in which the seismicity reflects active deformation at depth that is not clearly expressed in the near-surface geology. Direct connectivity between the Hosgri and Los Osos faults suggests a combined earthquake rupture is possible; however, the geometrical complexity along the offshore LOF may limit the extent of rupture.

Marine corrosion of mild steel at Lumut, Perak

NASA Astrophysics Data System (ADS)

Ting, Ong Shiou; Potty, Narayanan Sambu; Liew, Mohd. Shahir

2012-09-01

The corrosion rate of structural steels in the adverse marine and offshore environments affects the economic interest of offshore structures since the loss of steel may have significant impact on structural safety and performance. With more emphasis to maintain existing structures in service for longer time and hence to defer replacement costs, there is increasing interest in predicting corrosion rate at a given location for a given period of exposure once the protection coating or cathodic protection is lost. The immersion depth, salinity, steel composition and water pollution will be taken into account. Various corrosion allowances are prescribed for structural members by different standards. There are no studies to determine the appropriate corrosion allowance for steel structures in marine environment in Malaysia. The objectives of the research are to determine the nature and rate of corrosion in mm/year for steel structures in marine environment. It also tries to identify whether the corrosion rate is affected by differences in the chemical composition of the steels, and microalgae. Two sets of corrosion coupons of Type 3 Steel consisting of mild steel were fabricated and immersed in seawater using steel frames. The corrosion rate of the coupon in mm/ per year is estimated based on the material weight loss with time in service. The results are compared with recommendations of the code.

Establishment of a National Wind Energy Center at University of Houston

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Su Su

The DOE-supported project objectives are to: establish a national wind energy center (NWEC) at University of Houston and conduct research to address critical science and engineering issues for the development of future large MW-scale wind energy production systems, especially offshore wind turbines. The goals of the project are to: (1) establish a sound scientific/technical knowledge base of solutions to critical science and engineering issues for developing future MW-scale large wind energy production systems, (2) develop a state-of-the-art wind rotor blade research facility at the University of Houston, and (3) through multi-disciplinary research, introducing technology innovations on advanced wind-turbine materials, processing/manufacturingmore » technology, design and simulation, testing and reliability assessment methods related to future wind turbine systems for cost-effective production of offshore wind energy. To achieve the goals of the project, the following technical tasks were planned and executed during the period from April 15, 2010 to October 31, 2014 at the University of Houston: (1) Basic research on large offshore wind turbine systems (2) Applied research on innovative wind turbine rotors for large offshore wind energy systems (3) Integration of offshore wind-turbine design, advanced materials and manufacturing technologies (4) Integrity and reliability of large offshore wind turbine blades and scaled model testing (5) Education and training of graduate and undergraduate students and post- doctoral researchers (6) Development of a national offshore wind turbine blade research facility The research program addresses both basic science and engineering of current and future large wind turbine systems, especially offshore wind turbines, for MW-scale power generation. The results of the research advance current understanding of many important scientific issues and provide technical information for solving future large wind turbines with advanced design, composite materials, integrated manufacturing, and structural reliability and integrity. The educational program have trained many graduate and undergraduate students and post-doctoral level researchers to learn critical science and engineering of wind energy production systems through graduate-level courses and research, and participating in various projects in center’s large multi-disciplinary research. These students and researchers are now employed by the wind industry, national labs and universities to support the US and international wind energy industry. The national offshore wind turbine blade research facility developed in the project has been used to support the technical and training tasks planned in the program to accomplish their goals, and it is a national asset which is available for used by domestic and international researchers in the wind energy arena.« less

Quantitative Diagnostics of Multilayered Composite Structures with Ultrasonic Guided Waves

DTIC Science & Technology

2014-09-01

sensors. These IDT sensors were fabricated from thin wafer of piezoelectric lead zirconate titanate ( PZT ) substrates by using a pulse laser micro...pavement structures," J. Acoust. Soc. Am., vol. 116, no. 5, pp. 2902-2913, 2004. [9] E. Kostson and P. Fromme, " Fatigue crack growth monitoring in multi

Jurassic faults of southwest Alabama and offshore areas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mink, R.M.; Tew, B.H.; Bearden, B.L.

1991-03-01

Four fault groups affecting Jurassic strata occur in the southwest and offshore Alabama areas. They include the regional basement rift trend, the regional peripheral fault trend, the Mobile graben fault system, and the Lower Mobile Bay fault system. The regional basement system rift and regional peripheral fault trends are distinct and rim the inner margin of the eastern Gulf Coastal Plain. The regional basement rift trend is genetically related to the breakup of Pangea and the opening of the Gulf of Mexico in the Late Triassic-Early Jurassic. This fault trend is thought to have formed contemporaneously with deposition of Latemore » Triassic-Early Jurassic Eagle Mills Formation and to displace pre-Mesozoic rocks. The regional peripheral fault trend consists of a group of en echelon extensional faults that are parallel or subparallel to regional strike of Gulf Coastal Plain strata and correspond to the approximate updip limit of thick Louann Salt. Nondiapiric salt features are associated with the trend and maximum structural development is exhibited in the Haynesville-Smackover section. No hydrocarbon accumulations have been documented in the pre-Jurassic strata of southwest and offshore Alabama. Productive hydrocarbon reservoirs occur in Jurassic strata along the trends of the fault groups, suggesting a significant relationship between structural development in the Jurassic and hydrocarbon accumulation. Hydrocarbon traps are generally structural or contain a major structural component and include salt anticlines, faulted salt anticlines, and extensional fault traps. All of the major hydrocarbon accumulations are associated with movement of the Louann Salt along the regional peripheral fault trend, the Mobile graben fault system, or the Lower Mobile Bay fault system.« less

Hierarchical polymerized high internal phase emulsions synthesized from surfactant-stabilized emulsion templates.

PubMed

Wong, Ling L C; Villafranca, Pedro M Baiz; Menner, Angelika; Bismarck, Alexander

2013-05-21

In building construction, structural elements, such as lattice girders, are positioned specifically to support the mainframe of a building. This arrangement provides additional structural hierarchy, facilitating the transfer of load to its foundation while keeping the building weight down. We applied the same concept when synthesizing hierarchical open-celled macroporous polymers from high internal phase emulsion (HIPE) templates stabilized by varying concentrations of a polymeric non-ionic surfactant from 0.75 to 20 w/vol %. These hierarchical poly(merized)HIPEs have multimodally distributed pores, which are efficiently arranged to enhance the load transfer mechanism in the polymer foam. As a result, hierarchical polyHIPEs produced from HIPEs stabilized by 5 vol % surfactant showed a 93% improvement in Young's moduli compared to conventional polyHIPEs produced from HIPEs stabilized by 20 vol % of surfactant with the same porosity of 84%. The finite element method (FEM) was used to determine the effect of pore hierarchy on the mechanical performance of porous polymers under small periodic compressions. Results from the FEM showed a clear improvement in Young's moduli for simulated hierarchical porous geometries. This methodology could be further adapted as a predictive tool to determine the influence of hierarchy on the mechanical properties of a range of porous materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Kang; Wu, Sujun; Guan, Juan

Strong and tough epoxy composites are developed using a less-studied fibre reinforcement, that of natural silk. Two common but structurally distinct silks from the domestic B. mori/Bm and the wild A. pernyi/Ap silkworms are selected in fabric forms. We show that the toughening effects on silk-epoxy composites or SFRPs are dependent on the silk species and the volume fraction of silk. Both silks enhance the room-temperature tensile and flexural mechanical properties of the composite, whereas the more resilient Ap silk shows a more pronounced toughening effect and a lower critical reinforcement volume for the brittle-ductile transition. Specifically, our 60 vol.%more » Ap-SFRP displays a three-fold elevation in tensile and flexural strength, as compared to pure epoxy resin, with an order of magnitude higher breaking energy via a distinct, ductile failure mode. Importantly, the 60 vol.% Ap-SFRP remains ductile with 7% flexural elongation at lower temperatures (-50 °C). Under impact, these SFRPs show significantly improved energy absorption, and the 60 vol.% Ap-SFRP has an impact strength some eight times that of pure epoxy resin. Lastly, the findings demonstrate both marked toughening and strengthening effects for epoxy composites from natural silk reinforcements, which presents opportunities for mechanically superior and "green" structural composites.« less

Enhancing the Mechanical Toughness of Epoxy-Resin Composites Using Natural Silk Reinforcements

DOE PAGES

Yang, Kang; Wu, Sujun; Guan, Juan; ...

2017-09-20

Strong and tough epoxy composites are developed using a less-studied fibre reinforcement, that of natural silk. Two common but structurally distinct silks from the domestic B. mori/Bm and the wild A. pernyi/Ap silkworms are selected in fabric forms. We show that the toughening effects on silk-epoxy composites or SFRPs are dependent on the silk species and the volume fraction of silk. Both silks enhance the room-temperature tensile and flexural mechanical properties of the composite, whereas the more resilient Ap silk shows a more pronounced toughening effect and a lower critical reinforcement volume for the brittle-ductile transition. Specifically, our 60 vol.%more » Ap-SFRP displays a three-fold elevation in tensile and flexural strength, as compared to pure epoxy resin, with an order of magnitude higher breaking energy via a distinct, ductile failure mode. Importantly, the 60 vol.% Ap-SFRP remains ductile with 7% flexural elongation at lower temperatures (-50 °C). Under impact, these SFRPs show significantly improved energy absorption, and the 60 vol.% Ap-SFRP has an impact strength some eight times that of pure epoxy resin. Lastly, the findings demonstrate both marked toughening and strengthening effects for epoxy composites from natural silk reinforcements, which presents opportunities for mechanically superior and "green" structural composites.« less

Effects of sol-gel synthesis on 5Fe-15Mn-40Zn-40Ti-O mixed oxide structure and its H2S removal efficiency from industrial gas streams.

PubMed

Polychronopoulou, Kyriaki; Efstathiou, Angelos M

2009-06-15

A novel Fe-Mn-Zn-Ti-O mixed metal oxide has been developed for efficient low-temperature (25-50 degrees C) removal of H2S from a gas mixture containing 600 ppm H2S, 25 vol% H2, 7.5 vol % CO2, and 1-3 vol% H2O that simulates typical conditions experienced at the outlet of a bioreactor loaded with sulfate metal reducing bacteria (SMRB) that converts toxic Cr6+ and As5+ present in ground and surface waters and soils into nontoxic elements. During the latter conversion H2S gas is produced and has to be treated. In the present work it is demonstrated for the first time that by using the sol-gel synthesis route at given experimental conditions (e.g., metal precursor salts, solvent system, and solution pH), optimum structural properties for the Fe-Mn-Zn-Ti-O solid can be obtained for maximization of H2S uptake. In particular, at 25 degrees C an H2S uptake (0.085 g H2S/g solid) larger by at least a factor of 3 compared to a commercial Ni-based H2S absorbent material was obtained.

Industrializing Offshore Wind Power with Serial Assembly and Lower-cost Deployment - Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kempton, Willett

A team of engineers and contractors has developed a method to move offshore wind installation toward lower cost, faster deployment, and lower environmental impact. A combination of methods, some incremental and some breaks from past practice, interact to yield multiple improvements. Three designs were evaluated based on detailed engineering: 1) a 5 MW turbine on a jacket with pin piles (base case), 2) a 10 MW turbine on a conventional jacket with pin piles, assembled at sea, and 3) a 10 MW turbine on tripod jacket with suction buckets (caissons) and with complete turbine assembly on-shore. The larger turbine, assemblymore » ashore, and the use of suction buckets together substantially reduce capital cost of offshore wind projects. Notable capital cost reductions are: changing from 5 MW to 10 MW turbine, a 31% capital cost reduction, and assembly on land then single-piece install at sea an additional 9% capital cost reduction. An estimated Design 4) estimates further cost reduction when equipment and processes of Design 3) are optimized, rather than adapted to existing equipment and process. Cost of energy for each of the four Designs are also calculated, yielding approximately the same percentage reductions. The methods of Design 3) analyzed here include accepted structures such as suction buckets used in new ways, innovations conceived but previously without engineering and economic validation, combined with new methods not previously proposed. Analysis of Designs 2) and 3) are based on extensive engineering calculations and detailed cost estimates. All design methods can be done with existing equipment, including lift equipment, ports and ships (except that design 4 assumes a more optimized ship). The design team consists of experienced offshore structure designers, heavy lift engineers, wind turbine designers, vessel operators, and marine construction contractors. Comparing the methods based on criteria of cost and deployment speed, the study selected the third design. That design is, in brief: a conventional turbine and tubular tower is mounted on a tripod jacket, in turn atop three suction buckets. Blades are mounted on the tower, not on the hub. The entire structure is built in port, from the bottom up, then assembled structures are queued in the port for deployment. During weather windows, the fully-assembled structures are lifted off the quay, lashed to the vessel, and transported to the deployment site. The vessel analyzed is a shear leg crane vessel with dynamic positioning like the existing Gulliver, or it could be a US-built crane barge. On site, the entire structure is lowered to the bottom by the crane vessel, then pumping of the suction buckets is managed by smaller service vessels. Blades are lifted into place by small winches operated by workers in the nacelle without lift vessel support. Advantages of the selected design include: cost and time at sea of the expensive lift vessel are significantly reduced; no jack up vessel is required; the weather window required for each installation is shorter; turbine structure construction is continuous with a queue feeding the weather-dependent installation process; pre-installation geotechnical work is faster and less expensive; there are no sound impacts on marine mammals, thus minimal spotting and no work stoppage Industrializing Offshore Wind Power 6 of 96 9 for mammal passage; the entire structure can be removed for decommissioning or major repairs; the method has been validated for current turbines up to 10 MW, and a calculation using simple scaling shows it usable up to 20 MW turbines.« less

National Offshore Wind Energy Grid Interconnection Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, John P.; Liu, Shu; Ibanez, Eduardo

2014-07-30

The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States. A total of 54GW of offshore wind was assumed to be the target for the analyses conducted. A variety of issues are considered including: the anticipated staging of offshore wind; the offshore wind resource availability; offshore wind energy power production profiles; offshore wind variability; present and potential technologies for collection and delivery of offshore wind energy to the onshore grid; potential impacts to existing utility systemsmore » most likely to receive large amounts of offshore wind; and regulatory influences on offshore wind development. The technologies considered the reliability of various high-voltage ac (HVAC) and high-voltage dc (HVDC) technology options and configurations. The utility system impacts of GW-scale integration of offshore wind are considered from an operational steady-state perspective and from a regional and national production cost perspective.« less

High Power Combiner/Divider with Coupled Lines for Broadband Applications

DTIC Science & Technology

2017-03-20

novel isolation structure will also be presented. I. INTRODUCTION Power divider/combiners are traditionally used in the development of high power ...a novel Gysel divider/combiner structure have been demonstrated. The divider/combiner are applicable to various high- power , broadband radar, EW...Gysel Power Divider With Arbitrary Power Ratios and Filtering Responses Using Coupling Structure ,” IEEE Transactions on Microwave Theory and Tech., vol

Enhanced electrical conductivity and piezoresistive sensing in multi-wall carbon nanotubes/polydimethylsiloxane nanocomposites via the construction of a self-segregated structure.

PubMed

Wang, Ming; Zhang, Kai; Dai, Xin-Xin; Li, Yin; Guo, Jiang; Liu, Hu; Li, Gen-Hui; Tan, Yan-Jun; Zeng, Jian-Bing; Guo, Zhanhu

2017-08-10

Formation of highly conductive networks is essential for achieving flexible conductive polymer composites (CPCs) with high force sensitivity and high electrical conductivity. In this study, self-segregated structures were constructed in polydimethylsiloxane/multi-wall carbon nanotube (PDMS/MWCNT) nanocomposites, which then exhibited high piezoresistive sensitivity and low percolation threshold without sacrificing their mechanical properties. First, PDMS was cured and pulverized into 40-60 mesh-sized particles (with the size range of 250-425 μm) as an optimum self-segregated phase to improve the subsequent electrical conductivity. Then, the uncured PDMS/MWCNT base together with the curing agent was mixed with the abovementioned PDMS particles, serving as the segregated phase. Finally, the mixture was cured again to form the PDMS/MWCNT nanocomposites with self-segregated structures. The morphological evaluation indicated that MWCNTs were located in the second cured three-dimensional (3D) continuous PDMS phase, resulting in an ultralow percolation threshold of 0.003 vol% MWCNTs. The nanocomposites with self-segregated structures with 0.2 vol% MWCNTs achieved a high electrical conductivity of 0.003 S m -1 , whereas only 4.87 × 10 -10 S m -1 was achieved for the conventional samples with 0.2 vol% MWCNTs. The gauge factor GF of the self-segregated samples was 7.4-fold that of the conventional samples at 30% compression strain. Furthermore, the self-segregated samples also showed higher compression modulus and strength as compared to the conventional samples. These enhanced properties were attributed to the construction of 3D self-segregated structures, concentrated distribution of MWCNTs, and strong interfacial interaction between the segregated phase and the continuous phase with chemical bonds formed during the second curing process. These self-segregated structures provide a new insight into the fabrication of elastomers with high electrical conductivity and piezoresistive sensitivity for flexible force-sensitive materials.

Tectonic controls on the hydrocarbon habitats of the Barito, Kutei, and Tarakan Basins, Eastern Kalimantan, Indonesia: major dissimilarities in adjoining basins

NASA Astrophysics Data System (ADS)

Satyana, Awang Harun; Nugroho, Djoko; Surantoko, Imanhardjo

1999-04-01

The Barito, Kutei, and Tarakan Basins are located in the eastern half of Kalimantan (Borneo) Island, Indonesia. The basins are distinguished by their different tectonic styles during Tertiary and Pleistocene times. In the Barito Basin, the deformation is a consequence of two distinct, separate, regimes. Firstly, an initial transtensional regime during which sinistral shear resulted in the formation of a series of wrench-related rifts, and secondly, a subsequent transpressional regime involving convergent uplift, reactivating old structures and resulting in wrenching, reverse faulting and folding within the basin. Presently, NNE-SSW and E-W trending structures are concentrated in the northeastern and northern parts of the basin, respectively. In the northeastern part, the structures become increasingly imbricated towards the Meratus Mountains and involve the basement. The western and southern parts of the Barito Basin are only weakly deformed. In the Kutei Basin, the present day dominant structural trend is a series of tightly folded, NNE-SSW trending anticlines and synclines forming the Samarinda Anticlinorium which is dominant in the eastern part of the basin. Deformation is less intense offshore. Middle Miocene to Recent structural growth is suggested by depositional thinning over the structures. The western basin area is uplifted, large structures are evident in several places. The origin of the Kutei structures is still in question and proposed mechanisms include vertical diapirism, gravitational gliding, inversion through regional wrenching, detachment folds over inverted structures, and inverted delta growth-fault system. In the Tarakan Basin, the present structural grain is typified by NNE-SSW normal faults which are mostly developed in the marginal and offshore areas. These structures formed on older NW-SE trending folds and are normal to the direction of the basin sedimentary thickening suggesting that they developed contemporaneously with deposition, as growth-faults, and may be the direct result of sedimentary loading by successive deltaic deposits. Older structures were formed in the onshore basin, characterized by the N-S trending folds resulting from the collision of the Central Range terranes to the west of the basin. Hydrocarbon accumulations in the three basins are strongly controlled by their tectonic styles. In the Barito Basin, all fields are located in west-verging faulted anticlines. The history of tectonic inversion and convergent uplift of the Meratus Mountains, isostatically, have caused the generation, migration, and trapping of hydrocarbons. In the Kutei Basin, the onshore Samarinda Anticlinorium and the offshore Mahakam Foldbelt are prolific petroleum provinces, within which most Indonesian giant fields are located. In the offshore, very gentle folds also play a role as hydrocarbon traps, in association with stratigraphic entrapment. These structures have recently become primary targets for exploratory drilling. In the Tarakan Basin, the prominent NW-SE anticlines, fragmented by NE-SW growth-faults, have proved to be petroleum traps. The main producing pools are located in the downthrown blocks of the faults. Diverse tectonic styles within the producing basins of Kalimantan compel separate exploration approaches to each basin. To discover new opportunities in exploration, it is important to understand the structural evolution of neighbouring basins.

Mapping offshore portions of the Khlong Marui and Ranong faults in Thailand: Implications for seismic hazards in the Thai peninsula

NASA Astrophysics Data System (ADS)

Ramirez, H.; Furlong, K.; Pananont, P.; Krastel, S.; Nhongkai, S. N.

2017-12-01

Thailand experiences Mw < 6.5 earthquakes, but the frequency of these earthquakes is considerably less within Thailand than at plate boundaries. Faults in Thailand that are potentially active, but have not historically hosted a large earthquake pose an unknown seismic hazard. Two such faults are the Khlong Marui and Ranong faults, which are left lateral strike-slip faults that strike northeast across the Thai peninsula and have been assumed to continue into the Andaman Sea. The Ranong and Khlong Marui fault zones have clear surface expression onshore, but their offshore extent is unknown. An estimated 100 km of sinistral displacement has occurred in the last 52 million years on the Ranong fault zone and the Khlong Marui fault zone is assumed to be similar (Watkinson et al., 2008; Kornsawan and Morley, 2002). Five Mw < 4.5 earthquakes have occurred near the inferred offshore extension of the Ranong and Khlong Marui faults since 2005. However, the maximum earthquake magnitude possible and recurrence interval of events on these faults is unconstrained, leaving southern Thailand unprepared for a Mw < 6 earthquake. To constrain the location of offshore portion of these two faults we performed a marine seismic reflection survey in the Andaman Sea, and construct an offshore fault map. Additionally, we are working to resolve the depth extent of displacement associated with faulting in the seismic data to constrain the timing of fault motion. Using empirical scaling between fault area and earthquake size we will be able to estimate a maximum earthquake magnitude for the Ranong and Khlong Marui faults. This will provide additional information to help southern Thailand prepare for potential seismic events. Kornsawan, A., & Morley, C. K. (2002). The origin and evolution of complex transfer zones (graben shifts) in conjugate fault systems around the Funan Field, Pattani Basin, Gulf of Thailand. Journal of Structural Geology, 24(3), 435-449. http://doi.org/10.1016/S0191- 8141(01)00080-3 Watkinson, I., Elders, C., & Hall, R. (2008). The kinematic history of the Khlong Marui and Ranong Faults, southern Thailand. Journal of Structural Geology, 30, 1554-1571. http://doi.org/10.1016/j.jsg.2008.09.001

Pore structures and mechanical properties of porous titanium scaffolds by bidirectional freeze casting.

PubMed

Yan, Leiming; Wu, Jisi; Zhang, Lei; Liu, Xinli; Zhou, Kechao; Su, Bo

2017-06-01

Porous titanium scaffolds with long-range lamellar structure were fabricated using a novel bidirectional freeze casting method. Compared with the ordinarily porous titanium materials made by traditional freeze casting, the titanium walls can offer the structure of ordered arrays with parallel to each other in the transverse cross-sections. And titanium scaffolds with different pore width, wall size and porosity can be synthesized in terms of adjusting the fabrication parameters. As the titanium content was increased from 15vol.% to 25vol.%, the porosity and pore width decreased from 67±3% to 50±2% and 80±10μm to 67±7μm, respectively. On the contrary, as the wall size was increased from 18±2μm to 30±3μm, the compressive strength and stiffness were increased from 58±8MPa to 162±10MPa and from 2.5±0.7GPa to 6.5±0.9GPa, respectively. The porous titanium scaffolds with long-range lamellar structure and controllable pore structure produced in present work will be capable of having potential application as bone tissue scaffold materials. Copyright © 2016 Elsevier B.V. All rights reserved.

On-Orbit Assessment of Satellite Structural Properties via Robust Structural Health Monitoring

DTIC Science & Technology

2012-07-23

4-5] in aerospace applications. Compared to traditional SHM approaches using strain gages or Fiber Bragg Grating ( FBG ) sensors, the advantage of...decay model [20], principle stress directions for impact locations [21], use of Laser Doppler Vibrometer (LDV) [22] and FBG sensors [16, 23]. These...for Damage Localization in Flexural Structures Using Long-Gage FBG Sensors,” Structural Control Health Monitoring, Vol. 18, pp. 341-360, 2010. [24

Flammability limits of lithium-ion battery thermal runaway vent gas in air and the inerting effects of halon 1301

NASA Astrophysics Data System (ADS)

Karp, Matthew Eugene

Lithium-ion (rechargeable) and lithium-metal (non-rechargeable) battery cells put aircraft at risk of igniting and fueling fires. Lithium batteries can be packed in bulk and shipped in the cargo holds of freighter aircraft; currently lithium batteries are banned from bulk shipment on passenger aircraft [1]. The federally regulated Class C cargo compartment extinguishing system's utilization of a 5 %vol Halon 1301 knockdown concentration and a sustained 3 %vol Halon 1301 may not be sufficient at inerting lithium-ion battery vent gas and air mixtures [2]. At 5 %vol Halon 1301 the flammability limits of lithium-ion premixed battery vent gas (Li-Ion pBVG) in air range from 13.80 %vol to 26.07 %vol Li-Ion pBVG. Testing suggests that 8.59 %vol Halon 1301 is required to render all ratios of the Li-Ion pBVG in air inert. The lower flammability limit (LFL) and upper flammability limit (UFL) of hydrogen and air mixtures are 4.95 %vol and 76.52 %vol hydrogen, respectively. With the addition of 10 %vol and 20 %vol Halon 1301 the LFL is 9.02 %vol and 11.55 %vol hydrogen, respectively, and the UFL is 45.70 %vol and 28.39 %vol hydrogen, respectively. The minimum inerting concentration (MIC) of Halon 1301 in hydrogen and air mixtures is 26.72 %vol Halon 1301 at 16.2 %vol hydrogen. The LFL and UFL of Li-Ion pBVG and air mixtures are 7.88 %vol and 37.14 %vol Li-Ion pBVG, respectively. With the addition of 5 %vol, 7 %vol, and 8 %vol Halon 1301 the LFL is 13.80 %vol, 16.15 %vol, and 17.62 % vol Li-Ion pBVG, respectively, and the UFL is 26.07 %vol, 23.31 %vol, and 21.84 %vol Li- Ion pBVG, respectively. The MIC of Halon 1301 in Li-Ion pBVG and air mixtures is 8.59 %vol Halon 1301 at 19.52 %vol Li-Ion pBVG. Le Chatelier's mixing rule has been shown to be an effective measure for estimating the flammability limits of Li-Ion pBVGes. The LFL has a 1.79 % difference while the UFL has a 4.53 % difference. The state of charge (SOC) affects the flammability limits in an apparent parabolic manner, where the widest flammability limits are at or near 100 % SOC. [1] IATA. Lithium Battery Guidance Document. 7 Jan. 2016. Guidance for complying with provisions applicable to the transport by air of lithium batteries as set out in the 57th Edition of the IATA Dangerous Goods Regulations (DGR). [2] Webster, Harry. Flammability assessment of bulk-packed, rechargeable lithium-ion cells in transport category aircraft. Office of Aviation Research, Federal Aviation Administration, 2006.

Review of Literature on Probability of Detection for Magnetic Particle Nondestructive Testing

DTIC Science & Technology

2013-01-01

4 3.2 Offshore welded structures..................................................................................... 8 3.3 Aerospace...presented in Section 6. 2. Overview of Magnetic Particle Testing MPT is used in heavy engineering to inspect welds for surface-breaking... welded structures, and concluding with a summary of reliability information embedded in aerospace standards. 3.1 Aerospace It appears that the

[Work-related accidents on oil drilling platforms in the Campos Basin, Rio de Janeiro, Brazil].

PubMed

Freitas, C M; Souza, C A; Machado, J M; Porto, M F

2001-01-01

The offshore oil industry is characterized by complex systems in relation to technology and organization of work. Working conditions are hazardous, resulting in accidents and even occasional full-scale catastrophes. This article is the result of a study on work-related accidents in the offshore platforms in the Campos Basin, Rio de Janeiro State. The primary objective was to provide technical back-up for both workers' representative organizations and public authorities. As a methodology, we attempt to go beyond the immediate causes of accidents and emphasize underlying causes related to organizational and managerial aspects. The sources were used in such a way as to permit classification in relation to the type of incident, technological system, operation, and immediate and underlying causes. The results show the aggravation of safety conditions and the immediate need for public authorities and the offshore oil industry in Brazil to change the methods used to investigate accidents in order to identify the main causes in the organizational and managerial structure of companies.

Effects of sheens associated with offshore oil and gas development on the feather microstructure of pelagic seabirds.

PubMed

O'Hara, Patrick D; Morandin, Lora A

2010-05-01

Operational discharges of hydrocarbons from maritime activities can have major cumulative impacts on marine ecosystems. Small quantities of oil (i.e., 10 ml) results in often lethally reduced thermoregulation in seabirds. Thin sheens of oil and drilling fluids form around offshore petroleum production structures from currently permissible operational discharges of hydrocarbons. Methodology was developed to measure feather microstructure impacts (amalgamation index or AI) associated with sheen exposure. We collected feather samples from two common North Atlantic species of seabirds; Common Murres (Uria aalge) and Dovekies (Alle alle). Impacts were compared after feather exposure to crude oil and synthetic lubricant sheens of varying thicknesses. Feather weight and microstructure changed significantly for both species after exposure to thin sheens of crude oil and synthetic drilling fluids. Thus, seabirds may be impacted by thin sheens forming around offshore petroleum production facilities from discharged produced water containing currently admissible concentrations of hydrocarbons. (c) 2009. Published by Elsevier Ltd. All rights reserved.

Fluid pressure and shear zone development over the locked to slow slip region in Cascadia.

PubMed

Audet, Pascal; Schaeffer, Andrew J

2018-03-01

At subduction zones, the deep seismogenic transition from a frictionally locked to steady sliding interface is thought to primarily reflect changes in rheology and fluid pressure and is generally located offshore. The development of fluid pressures within a seismic low-velocity layer (LVL) remains poorly constrained due to the scarcity of dense, continuous onshore-offshore broadband seismic arrays. We image the subducting Juan de Fuca oceanic plate in northern Cascadia using onshore-offshore teleseismic data and find that the signature of the LVL does not extend into the locked zone. Thickening of the LVL down dip where viscous creep dominates suggests that it represents the development of an increasingly thick and fluid-rich shear zone, enabled by fluid production in subducting oceanic crust. Further down dip, episodic tremor, and slip events occur in a region inferred to have locally increased fluid pressures, in agreement with electrical resistivity structure and numerical models of fault slip.

Fluid pressure and shear zone development over the locked to slow slip region in Cascadia

PubMed Central

Audet, Pascal; Schaeffer, Andrew J.

2018-01-01

At subduction zones, the deep seismogenic transition from a frictionally locked to steady sliding interface is thought to primarily reflect changes in rheology and fluid pressure and is generally located offshore. The development of fluid pressures within a seismic low-velocity layer (LVL) remains poorly constrained due to the scarcity of dense, continuous onshore-offshore broadband seismic arrays. We image the subducting Juan de Fuca oceanic plate in northern Cascadia using onshore-offshore teleseismic data and find that the signature of the LVL does not extend into the locked zone. Thickening of the LVL down dip where viscous creep dominates suggests that it represents the development of an increasingly thick and fluid-rich shear zone, enabled by fluid production in subducting oceanic crust. Further down dip, episodic tremor, and slip events occur in a region inferred to have locally increased fluid pressures, in agreement with electrical resistivity structure and numerical models of fault slip. PMID:29536046

Proceedings: An international workshop on offshore lease abandonment and platform disposal: Technology, regulation, and environmental effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pulsipher, A.

This Proceedings volume includes papers prepared for an international workshop on lease abandonment and offshore platform disposal. The workshop was held April 15, 16, and 17, 1996, in New Orleans, Louisiana. Included in the volume are several plenary speeches and issue papers. prepared by six working groups, who discussed: Abandoning Wells; Abandoning Pipelines; Removing Facilities; Site Clearance; Habitat Management, Maintenance, and Planning; and Regulation and Policy. Also included are an introduction, an afterword (reprinted with the permission of its author, John Lohrenz), and, as Appendix C, the complete report of the National Research Council Marine Boards An Assessment of Techniquesmore » for Removing Fixed Offshore Structures, around which much of the discussion at the workshop was organized. Short biographies of many speakers, organizers, and chairpersons are included as Appendix A. Appendix B is a list of conference participants. Selected papers have been processes separately for inclusion in the Energy Science and Technology database.« less

Structural and mechanical defects of materials of offshore and onshore main gas pipelines after long-term operation

NASA Astrophysics Data System (ADS)

Maruschak, Pavlo; Panin, Sergey; Danyliuk, Iryna; Poberezhnyi, Lyubomyr; Pyrig, Taras; Bishchak, Roman; Vlasov, Ilya

2015-10-01

The study has established the main regularities of a fatigue failure of offshore gas steel pipes installed using S-lay and J-lay methods.We have numerically analyzed the influence of preliminary deformation on the fatigue life of 09Mn2Si steel at different amplitudes of cyclic loading. The results have revealed the regularities of formation and development of a fatigue crack in 17Mn1Si steel after 40 years of underground operation. The quantitative analysis describes the regularities of occurrence and growth of fatigue cracks in the presence of a stress concentration.

3D seismic attribute expressions of deep offshore Niger Delta

NASA Astrophysics Data System (ADS)

Anyiam, Uzonna Okenna

Structural and stratigraphic interpretation of 3D seismic data for reservoir characterization in an area affected by dense faulting, such as the Niger Delta, is typically difficult and strongly model driven because of problems with imaging. In the Freeman field, located about 120km offshore southwestern Niger Delta at about 1300m water depth, 3D seismic attribute-based analogs, and structural and stratigraphic based geometric models are combined to help enhance and constrain the interpretation. The objectives being to show how 3D seismic attribute analysis enhances seismic interpretation, develop structural style and stratigraphic architecture models and identify trap mechanisms in the study area; with the main purpose of producing structural and stratigraphic framework analogs to aid exploration and production companies, as well as researchers in better understanding the structural style, stratigraphic framework and trap mechanism of the Miocene to Pliocene Agbada Formation reservoirs in the deep Offshore Niger Delta Basin. A multidisciplinary approach which involved analyses of calculated variance-based coherence cube, spectral decomposition box probe and root-mean-square amplitude attributes, sequence stratigraphy based well correlation, and structural modeling; were undertaken to achieve these objectives. Studies reveal a massive northwest-southeast trending shale cored detachment fold anticline, with associated normal faults; interpreted to have been folded and faulted by localized compression resulting from a combination of differential loading on the deep-seated overpressured-ductile-undercompacted-marine Akata shale, and gravitational collapse of the Niger delta continental slope due to influx of sediments. Crestal extension resulting from this localized compression, is believed to have given rise to the synthetic, antithetic and newly observed crossing conjugate normal faults in the study area. This structure is unique to the existing types of principal oil field structures in the Niger Delta. Stratigraphic results show that the Mid-Miocene to Pliocene Agbada Formation reservoirs of the Freeman field occur as part of a channelized fan system; mostly deposited as turbidites in an unconfined distributary environment; except one that occurs as channel sand within a submarine canyon that came across and eroded previously deposited distributary fan complex, at the time. Hence, prospective area for hydrocarbon exploration is suggested southwest of the Freeman field.

Examining courses of sleep quality and sleepiness in full 2 weeks on/2 weeks off offshore day shift rotations.

PubMed

Riethmeister, V; Bültmann, U; De Boer, M R; Gordijn, M; Brouwer, S

2018-05-16

To better understand sleep quality and sleepiness problems offshore, we examined courses of sleep quality and sleepiness in full 2-weeks on/2-weeks off offshore day shift rotations by comparing pre-offshore (1 week), offshore (2 weeks) and post-offshore (1 week) work periods. A longitudinal observational study was conducted among N=42 offshore workers. Sleep quality was measured subjectively with two daily questions and objectively with actigraphy, measuring: time in bed (TIB), total sleep time (TST), sleep latency (SL) and sleep efficiency percentage (SE%). Sleepiness was measured twice a day (morning and evening) with the Karolinska Sleepiness Scale. Changes in sleep and sleepiness parameters during the pre/post and offshore work periods were investigated using (generalized) linear mixed models. In the pre-offshore work period, courses of SE% significantly decreased (p=.038). During offshore work periods, the courses of evening sleepiness scores significantly increased (p<.001) and significantly decreased during post-offshore work periods (p=.004). During offshore work periods, TIB (p<.001) and TST (p<.001) were significantly shorter, SE% was significantly higher (p=.002), perceived sleep quality was significantly lower (p<.001) and level of rest after wake was significantly worse (p<.001) than during the pre- and post-offshore work periods. Morning sleepiness was significantly higher during offshore work periods (p=.015) and evening sleepiness was significantly higher in the post-offshore work period (p=.005) compared to the other periods. No significant changes in SL were observed. Courses of sleep quality and sleepiness parameters significantly changed during full 2-weeks on/2-weeks off offshore day shift rotation periods. These changes should be considered in offshore fatigue risk management programmes.

Seismic-reflection studies, offshore Santa Maria Province, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bird, K.J.; Childs, J.R.; Taylor, D.J.

1991-02-01

Well data and seismic-reflection records are being analyzed to provide a subsurface geologic framework for the US Geological Survey's Santa Maria Province project. This project, jointly sponsored by the Evolution of Sedimentary Basins and Onshore Oil and Gas Investigations Programs, in a basin-evolution and petroleum geology study focusing on the geologically complex and tectonically active south-central California margin. The area embraces several basins and basin fragments including the onshore Santa Maria, offshore Santa Maria, Pismo, Huasna, Sur, Santa Lucia, and western Santa Barbara-Ventura. These basins have many similarities, including generally synchronous formation at about the end of the Oligocene, developmentmore » on a complex assemblage of Mesozoic tectonostratigraphic terranes, and basin fill consisting of Neogene clastic marine and nonmarine deposits, minor volcanic rocks, and organic-rich biogenous deposits of the Monterey Formation. Despite these similarities, basin origins are controversial and paleogeographies uncertain. In 1990, the US Geological Survey collected approximately 130 line-mi of multichannel seismic reflection data in seven profiles off-shore California from Morro Bay south to the western Santa Barbara Channel. These are the first US Geological Survey seismic data collected in this area since the early 1980s exploratory drilling began in the offshore Santa Maria basin. Profiles were generally oriented perpendicular to structural grain and located to intersect as many well-sites and pre-existing seismic profiles as possible. Profile orientation and spacing were designed to provide the offshore extensions of onshore well-correlation profiles currently under construction. With synthetic seismograms the authors are integrating the stratigraphy of the wells with these seismic-reflection records.« less

Seasonal and spatial variations of macro- and megabenthic community characteristics in two sections of the East China Sea

NASA Astrophysics Data System (ADS)

Xu, Yong; Li, Xinzheng; Ma, Lin; Dong, Dong; Kou, Qi; Sui, Jixing; Gan, Zhibin; Wang, Hongfa

2017-09-01

In spring and summer 2011, the macro- and megabenthic fauna in two sections of the East China Sea were investigated using an Agassiz net trawl to detect the seasonal and spatial variations of benthic community characteristics and the relation to environmental variables. The total number of species increased slightly from spring (131 species) to summer (133) whereas the percentage of Mollusca decreased significantly. The index of relative importance (IRI) indicated that the top five important species changed completely from spring to summer. Species number, abundance and biomass in summer were significantly higher than in spring, but no significant difference was observed among areas (coastal, transitional and oceanic areas, divided basically from inshore to offshore). Species richness ( d), diversity ( H') and evenness ( J') showed no significant seasonal or spatial variations. Cluster analysis and nMDS ordination identified three benthic communities from inshore to offshore, corresponding to the three areas. Analysis of Similarity (ANOSIM) indicated the overall significant difference in community structure between seasons and among areas. K-dominance curves revealed the high intrinsic diversity in the offshore area. Canonical correspondence analysis showed that the coastal community was positively correlated to total nitrogen and total organic carbon in spring, but negatively in summer; oceanic community was positively correlated to total nitrogen and total organic carbon in both seasons. Species such as Coelorhynchus multispinulosus, Neobythites sivicola, Lepidotrigla alata, Solenocera melantho, Parapenaeus fissuroides, Oratosquilla gonypetes and Spiropagurus spiriger occurred exclusively in the offshore oceanic area and their presence may reflect the influence of the offshore Kuroshio Current.

Submarine slope earthquake-induced instability and associated tsunami generation potential along the Hyblean-Malta Escarpment (offshore eastern Sicily, Italy)

NASA Astrophysics Data System (ADS)

Ausilia Paparo, Maria; Pagnoni, Gianluca; Zaniboni, Filippo; Tinti, Stefano

2016-04-01

The stability analysis of offshore margins is an important step for the assessment of natural hazard: the main challenge is to evaluate the potential slope failures and the consequent occurrence of submarine tsunamigenic landslides to mitigate the potential coastal damage to inhabitants and infrastructures. But the limited geotechnical knowledge of the underwater soil and the controversial scientific interpretation of the tectonic units make it often difficult to carry out this type of analysis reliably. We select the Hyblean-Malta Escarpment (HME), the main active geological structure offshore eastern Sicily, because the amount of data from historical chronicles, the records about strong earthquakes and tsunami, and the numerous geological offshore surveys carried out in recent years make the region an excellent scenario to evaluate slope failures, mass movements triggered by earthquakes and the consequent tsunamis. We choose several profiles along the HME and analyse their equilibrium conditions using the Minimun Lithostatic Deviation (MLD) method (Tinti and Manucci, 2006, 2008; Paparo et al. 2013), that is based on the limit-equilibrium theory. Considering the morphological and geotechnical features of the offshore slopes, we prove that large-earthquake shaking may lead some zones of the HME to instability, we evaluate the expected volumes involved in sliding and compute the associated landslide-tsunami through numerical tsunami simulations. This work was carried out in the frame of the EU Project called ASTARTE - Assessment, STrategy And Risk Reduction for Tsunamis in Europe (Grant 603839, 7th FP, ENV.2013.6.4-3).

Moored offshore structures - evaluation of forces in elastic mooring lines

NASA Astrophysics Data System (ADS)

Crudu, L.; Obreja, D. C.; Marcu, O.

2016-08-01

In most situations, the high frequency motions of the floating structure induce important effects in the mooring lines which affect also the motions of the structure. The experience accumulated during systematic experimental tests and calculations, carried out for different moored floating structures, showed a complex influence of various parameters on the dynamic effects. Therefore, it was considered that a systematic investigation is necessary. Due to the complexity of hydrodynamics aspects of offshore structures behaviour, experimental tests are practically compulsory in order to be able to properly evaluate and then to validate their behaviour in real sea. Moreover the necessity to carry out hydrodynamic tests is often required by customers, classification societies and other regulatory bodies. Consequently, the correct simulation of physical properties of the complex scaled models becomes a very important issue. The paper is investigating such kind of problems identifying the possible simplification, generating different approaches. One of the bases of the evaluation has been found consideringtheresults of systematic experimental tests on the dynamic behaviour of a mooring chain reproduced at five different scales. Dynamic effects as well as the influences of the elasticity simulation for 5 different scales are evaluated together. The paper presents systematic diagrams and practical results for a typical moored floating structure operating as pipe layer based on motion evaluations and accelerations in waves.

Sill induced hydrothermal venting: A summary of our current understanding

NASA Astrophysics Data System (ADS)

Jerram, Dougal; Svenesn, Henrik; Planke, Sverre; Millett, John; Reynolds, Pete

2017-04-01

Hydrothermal vent structures which are predominantly related with the emplacement of large (>1000 km3) intrusions into the sub-volcanic basins represent a specific style of piercement structure, where climate-forcing gases can be transferred into the atmosphere and hydrosphere. In this case, the types and volumes of gas produced by intrusions is heavily dependent on the host-rock sediment properties that they intrude through. The distribution of vent structures can be shown to be widespread in Large Igneous Provinces for example on both the Norwegian and the Greenland margins of the North Atlantic Igneous Province (NAIP). In this overview we assess the distribution, types and occurrence of hydrothermal vent structures associated with LIPs. There is particular focus on those within the NAIP using mapped examples from offshore seismic data as well as outcrop analogues, highlighting the variability of these structures and their deposits. As the availability of 3D data from offshore and onshore increases, the full nature of the volcanic stratigraphy from the subvolcanic intrusive complexes, through the main eruption cycles into the piercing vent structures, can be realised along the entirety of volcanic rifted margins and LIPs. This will help greatly in our understanding of the evolving palaeo-environments, and climate contributions during the evolution of these short lived massive volcanic events.

Ellipsis and the Structure of Expectation. San Jose State Occasional Papers in Linguistics, Vol. 1, November, 1975.

ERIC Educational Resources Information Center

Ross, Robert N.

This paper discusses one way of exploring how we perceive and understand the connections between some parts of texts, or between one sentence and the whole discourse. Understanding ellipsis involves non-syntactic understanding; the semantic structure is responsible for our understanding of elliptical sentences and encoding the knowledge contained…

Structurally Efficient Anisotropic Organized Reticulated structures for Cooling of Electronics and Sensors

DTIC Science & Technology

2006-08-31

Chang and You [19971 and Mukherjee and Mudawar [20031. For each experiment, data is collected by varying the heat flux from high to low. This is...Science", Vol. 20, 1965, pp. 237-246. Mukherjee, S., and Mudawar , I., 2003, "Smart Pumpless Loop for Micro-Channel Electronic Cooling Using Flat and

Discrete Structure-Point Testing: Problems and Alternatives. TESL Reporter, Vol. 9, No. 4.

ERIC Educational Resources Information Center

Aitken, Kenneth G.

This paper presents some reasons for reconsidering the use of discrete structure-point tests of language proficiency, and suggests an alternative basis for designing proficiency tests. Discrete point tests are one of the primary tools of the audio-lingual method of teaching a foreign language and are based on certain assumptions, including the…

Investigation of Structure/Fluid Interaction in Piping Systems Using an Intensity Measurement Approach.

DTIC Science & Technology

1987-07-01

of vibrational power flow had been considered by experiments in the area of statistical energy analysis (SEA)8, 9 using other measurement ipproaches...Constants in Statistical Energy Analysis of Structure," J. Acoust. Soc. Am. Vol. 52, No. 2, pp. 516-524 (1973) 9. Fahy, F. and R. Pierri, "Application of

Experiment on the Effects of Storage Duration of Biodiesel produced from Crude Palm Oil, Waste Cooking oil and Jatropha

NASA Astrophysics Data System (ADS)

Nanihar, Nadiarulah; Khalid, Amir; Mustaffa, Norrizal; Jaat, Norrizam; Sapit, Azwan; Razali, Azahari; Sunar, Norshuhaila Mohamed

2017-10-01

Biodiesel based on vegetable oil is an alternative that had various advantage in term of sustainability and environmental attractive compare to others conventional diesel. Biodiesel is product of any fat or oil that derived from any organic sources through a refinery process called transesterification process. This research investigates the effects of storage duration and variant ambient condition on the biodiesel properties and characteristics. In this study, there are three types of blending which is 5vol% blends ( 5vol% plant oil 95vol% diesel), 10vol% blending (10vol% plant oil and 90vol% diesel) and 15vol% blending (15vol% plant oil and 85vol% diesel) each called CPO5 (crude palm oil 5vol%), CPO10 (crude palm oil 10vol%),CPO15 (crude palm oil 15vol%), JO5 (jatropha oil 5vol%), JO10 (jatropha oil 10vol%),and JO15 (jatropha oil 15vol%) respectively. Biodiesel samples were stored at indoor condition and outdoor condition for a 3 months period. The fuel properties such as acid value, viscosity, density, water content and flash point are observed with the laboratory instrument. Flash point value and water content increased under both of indoor and outdoor condition and a steady data for viscosity and density. However, acid value at indoor condition nearly constant but increased dramatically for outdoor condition over the time.

Rare Earth Doped GaN Laser Structures Using Metal Modulated Epitaxy

DTIC Science & Technology

2015-03-30

from Eu-doped GaN,” Appl. Phys. Lett., vol. 75, pp. 1189–1191, 1999. 24. D. S . Lee and A. J. Steckl, “Room-temperature-grown rare- earth -doped GaN...luminescent thin films,” Appl. Phys. Lett., vol. 79, pp. 1962–1964,2001. 25. D. S . Lee and A. J. Steckl, “Lateral color integration on rare- earth doped... s . 0.259nm/ s =1.14E13cm-2/ s =1 ML/ s .Our plasma source was optimized to work at 1.5 sccm and 230 W RF power and it provides a growth rate of 0.8 ML/ s

Seafloor bathymetry and gravity from the ALBACORE marine seismic experiment offshore southern California

NASA Astrophysics Data System (ADS)

Shintaku, N.; Weeraratne, D. S.; Kohler, M. D.

2010-12-01

Although the North America side of the plate boundary surrounding the southern California San Andreas fault region is well studied and instrumented, the Pacific side of this active tectonic boundary is poorly understood. In order to better understand this complex plate boundary offshore, its microplate structures, deformation, and the California Borderland formation, we have recently conducted the first stage of a marine seismic experiment (ALBACORE - Asthenospheric and Lithospheric Broadband Architecture from the California Offshore Region Experiment) deploying 34 ocean bottom seismometers offshore southern California in August 2010. We present preliminary data consisting of seafloor bathymetry and free air gravity collected from this experiment. We present high-resolution maps of bathymetry and gravity from the ALBACORE experiment compiled with previous ship track data obtained from the NGDC (National Geophysical Data Center) and the USGS. We use gravity data from Smith and Sandwell and study correlations with ship track bathymetry data for the features described below. We observe new seafloor geomorphological features far offshore and within the Borderland. Steep canyon walls which line the edges of the Murray fracture zone with possible volcanic flows along the canyon floor were mapped by multibeam bathymetry for the first time. Deep crevices juxtaposed with high edifices of intensely deformed plateaus indicate high strain deformation along the arcuate boundary of the Arguello microplate. Small volcanic seamounts are mapped which straddle the Ferrelo fault (Outer Borderland) and San Pedro fault (Inner Borderland), and appear to exhibit fracture and fault displacement of a portion of the volcanic centers in a left-lateral sense. A large landslide is also imaged extending approximately 6 miles in length and 3 miles in width in the Santa Cruz basin directly south of Santa Rosa Island. Deformation associated with capture of Arguello and Patton microplates by the Pacific plate is studied as well as deformation surrounding the Murray fracture zone near the California shore. Faults in the Borderland identified by improved sea floor mapping may indicate offshore earthquake sources.

The OMEGA system for marine bioenergy, wastewater treatment, environmental enhancement, and aquaculture

NASA Astrophysics Data System (ADS)

Trent, J. D.

2013-12-01

OMEGA is an acronym for Offshore Membrane Enclosure for Growing Algae. The OMEGA system consists of photobioreactors (PBRs) made of flexible, inexpensive clear plastic tubes attached to floating docks, anchored offshore in naturally or artificially protected bays [1]. The system uses domestic wastewater and CO2 from coastal facilities to provide water, nutrients, and carbon for algae cultivation [2]. The surrounding seawater maintains the temperature inside the PBRs and prevents the cultivated (freshwater) algae from becoming invasive species in the marine environment (i.e., if a PBR module accidentally leaks, the freshwater algae that grow in wastewater cannot survive in the marine environment). The salt gradient between seawater and wastewater is used for forward osmosis (FO) to concentrate nutrients and facilitate algae harvesting [3]. Both the algae and FO clean the wastewater, removing nutrients as well as pharmaceuticals and personal-care products [4]. The offshore infrastructure provides a large surface area for solar-photovoltaic arrays and access to offshore wind or wave generators. The infrastructure can also support shellfish, finfish, or seaweed aquaculture. The economics of the OMEGA system are supported by a combination of biofuels production, wastewater treatment, alternative energy generation, and aquaculture. By using wastewater and operating offshore from coastal cities, OMEGA can be located close to wastewater and CO2 sources and it can avoid competing with agriculture for water, fertilizer, and land [5]. By combining biofuels production with wastewater treatment and aquaculture, the OMEGA system provides both products and services, which increase its economic feasibility. While the offshore location has engineering challenges and concerns about the impact and control of biofouling [6], large OMEGA structure will be floating marine habitats and will create protected 'no-fishing' zones that could increase local biodiversity and fishery productivity. Potential test sites for the next phase of OMEGA (1-hectare integrated system) will be discussed.

Numerical and experimental results on the spectral wave transfer in finite depth

NASA Astrophysics Data System (ADS)

Benassai, Guido

2016-04-01

Determination of the form of the one-dimensional surface gravity wave spectrum in water of finite depth is important for many scientific and engineering applications. Spectral parameters of deep water and intermediate depth waves serve as input data for the design of all coastal structures and for the description of many coastal processes. Moreover, the wave spectra are given as an input for the response and seakeeping calculations of high speed vessels in extreme sea conditions and for reliable calculations of the amount of energy to be extracted by wave energy converters (WEC). Available data on finite depth spectral form is generally extrapolated from parametric forms applicable in deep water (e.g., JONSWAP) [Hasselmann et al., 1973; Mitsuyasu et al., 1980; Kahma, 1981; Donelan et al., 1992; Zakharov, 2005). The present paper gives a contribution in this field through the validation of the offshore energy spectra transfer from given spectral forms through the measurement of inshore wave heights and spectra. The wave spectra on deep water were recorded offshore Ponza by the Wave Measurement Network (Piscopia et al.,2002). The field regressions between the spectral parameters, fp and the nondimensional energy with the fetch length were evaluated for fetch-limited sea conditions. These regressions gave the values of the spectral parameters for the site of interest. The offshore wave spectra were transfered from the measurement station offshore Ponza to a site located offshore the Gulf of Salerno. The offshore local wave spectra so obtained were transfered on the coastline with the TMA model (Bouws et al., 1985). Finally the numerical results, in terms of significant wave heights, were compared with the wave data recorded by a meteo-oceanographic station owned by Naples Hydrographic Office on the coastline of Salerno in 9m depth. Some considerations about the wave energy to be potentially extracted by Wave Energy Converters were done and the results were discussed.

Geologic framework of the offshore region adjacent to Delaware

USGS Publications Warehouse

Benson, R.N.; Roberts, J.H.

1989-01-01

Several multichannel, common depth point (CDP) seismic reflection profiles concentrated in the area of the entrance to Delaware Bay provide a tie between the known onshore geology of the Coastal Plain of Delaware and the offshore geology of the Baltimore Canyon Trough. The data provide a basis for understanding the geologic framework and petroleum resource potential of the area immediately offshore Delaware. Our research has focused on buried early Mesozoic rift basins and their geologic history. Assuming that the buried basins are analogous to the exposed Newark Supergroup basins of Late Triassic-Early Jurassic age, the most likely possibility for occurrence of hydrocarbon source beds in the area of the landward margin of the Baltimore Canyon Trough is presumed to be lacustrine, organic-rich shales probably present in the basins. Although buried basins mapped offshore Delaware are within reach of drilling, no holes have been drilled to date; therefore, direct knowledge of source, reservoir, and sealing beds is absent. Buried rift basins offshore Delaware show axial trends ranging from NW-SE to NNE-SSW. Seismic reflection profiles are too widely spaced to delineate basin boundaries accurately. Isopleths of two-way travel time representing basin fill suggest that, structurally, the basins are grabens and half-grabens. As shown on seismic reflection profiles, bounding faults of the basins intersect or merge with low-angle fault surfaces that cut the pre-Mesozoic basement. The rift basins appear to have formed by Mesozoic extension that resulted in reverse motion on reactivated basement thrust faults that originated from compressional tectonics during the Paleozoic. Computer-plotted structure contour maps derived from analysis of seismic reflection profiles provide information on the burial history of the rift basins. The postrift unconformity bevels the rift basins and, in the offshore area mapped, ranges from 2000 to 12,000 m below present sea level. The oldest postrift sediments that cover the more deeply buried rift basins are estimated to be of Middle Jurassic age (Bajocian-Bathonian), the probable time of opening of the Atlantic Ocean basin and onset of continental drift about 175-180 m.y. ago. By late Oxfordian-early Kimmeridgian time, the less deeply buried basins nearshore Delaware had been covered. A time-temperature index of maturity plot of one of the basins indicates that only dry gas would be present in reservoirs in synrift rocks buried by more than 6000 m of postrift sediments and in the oldest (Bathonian?-Callovian?) postrift rocks. Less deeply buried synrift rocks landward of the basin modeled might still be within the oil generation window. ?? 1989.

Different key roles of mesoscale oceanographic structures and ocean bathymetry in shaping larval fish distribution pattern: A case study in Sicilian waters in summer 2009

NASA Astrophysics Data System (ADS)

Cuttitta, Angela; Quinci, Enza Maria; Patti, Bernardo; Bonomo, Sergio; Bonanno, Angelo; Musco, Marianna; Torri, Marco; Placenti, Francesco; Basilone, Gualtiero; Genovese, Simona; Armeri, Grazia Maria; Spanò, Antonina; Arculeo, Marco; Mazzola, Antonio; Mazzola, Salvatore

2016-09-01

Fish larvae data collected in year 2009 were used to examine the effects of particular environmental conditions on the structure of larval assemblages in two oligotrophic Mediterranean areas (the Southern Tyrrhenian Sea and the Strait of Sicily). For this purpose, relationships with environmental variables (temperature, salinity and fluorescence), zooplankton biomass, water circulation and bathymetry are discussed. Hydrodynamic conditions resulted very differently between two study areas. The Southern Tyrrhenian Sea was characterized by moderate shallow circulation compared to the Strait of Sicily. In this framework, distribution pattern of larval density in the Tyrrhenian Sea was mainly driven by bathymetry, due to spawning behavior of adult fish. There, results defined four assemblages: two coastal assemblages dominated by pelagic and demersal families and two oceanic assemblages dominated by mesopelagic species more abundant in western offshore and less abundant in eastern offshore. The assemblage variations in the western side was related to the presence of an anti-cyclonic gyre in the northern side of the Gulf of Palermo, while in the eastern side the effect of circulation was not very strong and the environmental conditions rather than the dispersal of species determined the larval fish communities structure. Otherwise in the Strait of Sicily the currents were the main factor governing the concentration and the assemblage structure. In fact, the distribution of larvae was largely consistent with the branch of the Atlantic Ionian Stream (AIS). Moreover, very complex oceanographic structures (two cyclonic circulations in the western part of the study area and one anti-cyclonic circulation in the eastern part) caused the formation of uncommon spatial distribution of larval fish assemblages, only partially linked to bathymetry of the study area. Typically coastal larvae (pelagic families: Engraulidae and Clupeidae) were mostly concentrated in the offshore areas and off Capo Passero, where the presence of a thermo-haline front maintained their position in an area with favourable conditions for larval fish feeding and growth.

Deep crustal structure of the northeastern margin of the Arabian plate from seismic and gravity data

NASA Astrophysics Data System (ADS)

Pilia, Simone; Ali, Mohammed; Watts, Anthony; Keats, Brook; Searle, Mike

2017-04-01

The United Arab Emirates-Oman mountains constitute a 700 km long, 50 km wide compressional orogenic belt that developed during the Cainozoic on an underlying extensional Tethyan rifted margin. It contains the world's largest and best-exposed thrust sheet of oceanic crust and upper mantle (Semail Ophiolite), which was obducted onto the Arabian rifted continental margin during the Late Cretaceous. Although the shallow structure of the UAE-Oman mountain belt is reasonably well known through the exploitation of a diverse range of techniques, information on deeper structure remains little. Moreover, the mechanisms by which dense oceanic crustal and mantle rocks are emplaced onto less dense and more buoyant continental crust are still controversial and remain poorly understood. The focus here is on an active-source seismic and gravity E-W transect extending from the UAE-mountain belt to the offshore. Seismic refraction data were acquired using the survey ship M/V Hawk Explorer, which was equipped with a large-volume airgun array (7060 cubic inches, 116 liters). About 400 air gun shots at 50-second time interval were recorded on land by eight broadband seismometers. In addition, reflection data were acquired at 20 seconds interval and recorded by a 5-km-long multichannel streamer. Results presented here include an approximately 85 km long (stretching about 35 km onshore and 50 km offshore) P-wave velocity crustal profile derived by a combination of forward modelling and inversion of both diving and reflected wave traveltimes using RAYINVR software. We employ a new robust algorithm based on a Monte Carlo approach (VMONTECARLO) to address the velocity model uncertainties. We find ophiolite seismic velocities of about 5.5 km/s and a thick sedimentary package in the offshore. Furthermore, the velocity model reveals a highly stretched crust with the Moho discontinuity lying at about 20 km. A prestack depth-migrated profile (about 50 km long) coincident with the offshore part of the refraction profile shows a thick sequence (up to about 10 km) of seaward dipping sediments that are offset by a number of listric (normal) faults, some of which intersect the seabed and so reflect recent tectonic activity. The trend of the Bouguer anomaly provides further constraints on the deeper structure of the margin and appears to confirm the presence of a stretched crust.

Paleohighs and Paleolows in the Basement Rocks of the Eastern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Robinson, D.; Weislogel, A. L.

2017-12-01

The Eastern Gulf of Mexico has topography on the basement rocks composed of igneous and metamorphic rocks as well as some sedimentary rocks underneath a relatively thin salt layer with 3-6 km of topography relief. Paleohighs from south to north include Sarasota Arch, Middle Ground Arch/Southern Platform, Pensacola Arch, Conecuh Ridge Complex, Baldwin High, Wiggins Arch and Choctaw Ridge Complex. Paleolows from south to north include South Florida Basin, Tampa Embayment, Apalachicola Basin/Desoto Canyon Salt Basin, Conecuh Embayment, Manila Embayment and the Mississippi Interior Salt Basin. The topography on the basement is a result of several collisions between Laurentian and Gondwana to produce Pangea with final suturing during Pennsylvanian time and also from extension in Late Triassic to Early Cretaceous time as a result of the opening of the Gulf and rotation of Yucatan. Heterogeneities related to previous collisions may have also factored into producing these paleohighs and paleolows. A series of grabens and half-grabens, trending northeast-southwest from northwest-southeast directed extension and with the sedimentary rocks, exist on the continents and appear to be present in the offshore under the salt. We know the paleolows were depositional pathways to funnel sediments from onshore to offshore via water and wind in Jurassic and maybe Cretaceous times. Many tectonic models call for the paleohighs and paleolows to be structurally controlled; however, finding the faults called upon to control the "horst and graben" structures is challenging. We present data from several seismic studies that questions the idea that these paleohighs and paleolows are the result of horst and graben extension. Half grabens exist in the offshore with graben bounding faults northeast-southwest; however, down is to the north instead of the anticipated down to the south. Instead, the basement paleohighs and paleolows in the offshore Eastern Gulf of Mexico may be the result of preexisting lithologic and structural weaknesses in conjunction with lithospheric thinning. Some of the basement paleohighs and paleolows in the onshore are related to the buried Appalachian fold-thrust belt.

Structure of the Lithosphere-Asthenosphere Boundary Onshore and Offshore the California Continental Margin from Three-Dimensional Seismic Anisotropy

NASA Astrophysics Data System (ADS)

Gomez, C. D.; Escobar, L., Sr.; Rathnayaka, S.; Weeraratne, D. S.; Kohler, M. D.

2016-12-01

The California continental margin, a major transform plate boundary in continental North America, is the locus of complex tectonic stress fields that are important in interpreting both remnant and ongoing deformational strain. Ancient subduction of the East Pacific Rise spreading center, the rotation and translation of tectonic blocks and inception of the San Andreas fault all contribute to the dynamic stress fields located both onshore and offshore southern California. Data obtained by the ALBACORE (Asthenospheric and Lithospheric Broadband Architecture from the California Offshore Region Experiment) and the CISN (California Integrated Seismic Network) seismic array are analyzed for azimuthal anisotropy of Rayleigh waves from 80 teleseismic events at periods 16 - 78 s. Here we invert Rayleigh wave data for shear wave velocity structure and three-dimensional seismic anisotropy in the thee regions designated within the continental margin including the continent, seafloor and California Borderlands. Preliminary results show that seismic anisotropy is resolved in multiple layers and can be used to determine the lithosphere-asthenosphere boundary (LAB) in offshore and continental regions. The oldest seafloor in our study at age 25-35 Ma indicates that the anisotropic transition across the LAB occurs at 73 km +/- 25 km with the lithospheric fast direction oriented WNW-ESE, consistent with current Pacific plate motion direction. The continent region west of the San Andreas indicates similar WNW-ESE anisotropy and LAB depth. Regions east of the San Andreas fault indicate NW-SE anisotropy transitioning to a N-S alignment at 80 km depth north of the Garlock fault. The youngest seafloor (15 - 25 Ma) and outer Borderlands indicate a more complex three layer fabric where shallow lithospheric NE-SW fast directions are perpendicular with ancient Farallon subduction arc, a mid-layer with E-W fast directions are perpendicular to remnant fossil fabric, and the deepest layer indicates NW-SE fast directions below the LAB likely controlled by current Pacific plate motion. The inner Borderland indicates two layer anisotropic structure with a shallow NW-SE lithospheric fast direction that changes to NE-SW fast directions below the LAB, possibly consistent with the ancient subduction direction.

P-wave velocity structure offshore central Sumatra: implications for compressional and strike-slip faulting

NASA Astrophysics Data System (ADS)

Karplus, M.; Henstock, T.; McNeill, L. C.; Vermeesch, P. M. T.; Barton, P. J.

2014-12-01

The Sunda subduction zone features significant along-strike structural variability including changes in accretionary prism and forearc morphology. Some of these changes have been linked to changes in megathrust faulting styles, and some have been linked to other thrust and strike-slip fault systems across this obliquely convergent margin (~54-58 mm/yr convergence rate, 40-45 mm/yr subduction rate). We examine these structural changes in detail across central Sumatra, from Siberut to Nias Island, offshore Indonesia. In this area the Investigator Fracture Zone and the Wharton Fossil Ridge, features with significant topography, are being subducted, which may affect sediment thickness variation and margin morphology. We present new seismic refraction P-wave velocity models using marine seismic data collected during Sonne cruise SO198 in 2008. The experiment geometry consisted of 57 ocean bottom seismometers, 23 land seismometers, and over 10,000 air gun shots recorded along ~1750 km of profiles. About 130,000 P-wave first arrival refractions were picked, and the picks were inverted using FAST (First Arrivals Refraction Tomography) 3-D to give a velocity model, best-resolved in the top 25 km. Moho depths, crustal composition, prism geometry, slab dip, and upper and lower plate structures provide insight into the past and present tectonic processes at this plate boundary. We specifically examine the relationships between velocity structure and faulting locations/ styles. These observations have implications for strain-partitioning along the boundary. The Mentawai Fault, located west of the forearc basin in parts of Central Sumatra, has been interpreted variably as a backthrust, strike-slip, and normal fault. We integrate existing data to evaluate these hypotheses. Regional megathrust earthquake ruptures indicate plate boundary segmentation in our study area. The offshore forearc west of Siberut is almost aseismic, reflecting the locked state of the plate interface, which last ruptured in 1797. The weakly-coupled Batu segment experiences sporadic clusters of events near the forearc slope break. The Nias segment in the north ruptured in the 2005 M8.7 earthquake. We compare P-wave velocity structure to the earthquake data to examine potential links between lithospheric structure and seismogenesis.

Assessing the impact of Hurricanes Irene and Sandy on the morphology and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York

USGS Publications Warehouse

Schwab, William C.; Baldwin, Wayne E.; Denny, Jane F.

2016-01-15

This report documents the changes in seabed morphology and modern sediment thickness detected on the inner continental shelf offshore of Fire Island, New York, before and after Hurricanes Irene and Sandy made landfall. Comparison of acoustic backscatter imagery, seismic-reflection profiles, and bathymetry collected in 2011 and in 2014 show that sedimentary structures and depositional patterns moved alongshore to the southwest in water depths up to 30 meters during the 3-year period. The measured lateral offset distances range between about 1 and 450 meters with a mean of 20 meters. The mean distances computed indicate that change tended to decrease with increasing water depth. Comparison of isopach maps of modern sediment thickness show that a series of shoreface-attached sand ridges, which are the dominant sedimentary structures offshore of Fire Island, migrated toward the southwest because of erosion of the ridge crests and northeast-facing flanks as well as deposition on the southwest-facing flanks and in troughs between individual ridges. Statistics computed suggest that the modern sediment volume across the about 81 square kilometers of common sea floor mapped in both surveys decreased by 2.8 million cubic meters, which is a mean change of –0.03 meters, which is smaller than the resolution limit of the mapping systems used.

Offshore seismicity in the southeastern sea of Korea

NASA Astrophysics Data System (ADS)

Park, H.; Kang, T. S.

2017-12-01

The offshore southeastern sea area of Korea appear to have a slightly higher seismicity compared to the rest of the Korean Peninsula. According to the earthquake report by Korean Meteorological Administration (KMA), earthquakes over ML 3 has persistently occurred over once a year during the last ten years. In this study, we used 33 events in KMA catalog, which occurred in the offshore Ulsan (35.0°N-35.85°N, 129.45°E-130.75°E) from April 2007 to June 2017, as mother earthquakes. The waveform matching filter technique was used to precisely detect microearthquakes (child earthquakes) that occurred after mother earthquakes. It is the optimal linear filter for maximizing the signal-to-noise ratio in the presence of additive stochastic noise. Initially, we used the continuous seismic waveforms available from KMA and the Korea Institute of Geosciences and Mineral Resources. We added the data of F-net to increase the reliability of the results. The detected events were located by using P- and S-wave arrival times. The hypocentral depths were constrained by an iterative optimal solution technique which is proven to be effective under the poorly known structure. Focal mechanism solutions were obtained from the analysis of P-wave first-motion polarities. Seismicity patterns of microearthquakes and their focal mechanism results were analyzed to understand their seismogenic characteristics and their relationship to subsea seismotectonic structures.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodwin, Andrew; Wang, Weiyu; Kang, Nam -Goo

We present in this paper the synthesis of poly(n-butyl acrylate)-g-poly(methyl methacrylate) (PnBA-g-PMMA) multigraft copolymers via a grafting-through (macromonomer) approach. The synthesis was performed using two controlled polymerization techniques. The PMMA macromonomer was obtained by high-vacuum anionic polymerization followed by the copolymerization of n-butyl acrylate and PMMA macromonomer using reversible addition–fragmentation chain transfer (RAFT) polymerization to yield the desired all-acrylic multigraft structures. The PnBA-g-PMMA multigraft structures exhibit randomly spaced branch points with various PMMA contents, ranging from 15 to 40 vol %, allowing an investigation into how physical properties vary with differences in the number of branch points and molecular weightmore » of grafted side chains. The determination of molecular weight and polydispersity indices of both the PMMA macromonomer and the graft copolymers was carried out using size exclusion chromatography with triple detection, and the structural characteristics of both the macromonomer and PnBA-g-PMMA graft materials were characterized by 1H and 13C NMR. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was employed for monitoring the macromonomer synthesis. Thermal characteristics of the materials were analyzed using differential scanning calorimetry and thermogravimetric analysis. The mechanical performance of the graft materials was characterized by rheology and dynamic mechanical analysis, revealing that samples with PMMA content of 25–40 vol % exhibit superior elastomeric properties as compared to materials containing short PMMA side chains or <25 vol % PMMA. In conclusion, atomic force microscopy showed a varying degree of microphase separation between the glassy and rubbery components that is strongly dependent on PMMA side chain molecular weight.« less

Quick-Connect, Self-Alining Latch

NASA Technical Reports Server (NTRS)

Burns, G. C.; Williams, E. J.

1983-01-01

Sturdy latch tolerates 10 degrees of angular mismatch in joining structural elements. Hexagonal passive plate nests in active plate, guided by capture plates and alinement keys and grooves. Center hole in both active and passive plates is 1 meter in diameter. Latch has possible uses a pipe joint, connector for parts of portable structures, and fitting for marine risers on offshore drilling rigs.

Simplified rotor load models and fatigue damage estimates for offshore wind turbines.

PubMed

Muskulus, M

2015-02-28

The aim of rotor load models is to characterize and generate the thrust loads acting on an offshore wind turbine. Ideally, the rotor simulation can be replaced by time series from a model with a few parameters and state variables only. Such models are used extensively in control system design and, as a potentially new application area, structural optimization of support structures. Different rotor load models are here evaluated for a jacket support structure in terms of fatigue lifetimes of relevant structural variables. All models were found to be lacking in accuracy, with differences of more than 20% in fatigue load estimates. The most accurate models were the use of an effective thrust coefficient determined from a regression analysis of dynamic thrust loads, and a novel stochastic model in state-space form. The stochastic model explicitly models the quasi-periodic components obtained from rotational sampling of turbulent fluctuations. Its state variables follow a mean-reverting Ornstein-Uhlenbeck process. Although promising, more work is needed on how to determine the parameters of the stochastic model and before accurate lifetime predictions can be obtained without comprehensive rotor simulations. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Spatial-temporal analysis of coherent offshore wind field structures measured by scanning Doppler-lidar

NASA Astrophysics Data System (ADS)

Valldecabres, L.; Friedrichs, W.; von Bremen, L.; Kühn, M.

2016-09-01

An analysis of the spatial and temporal power fluctuations of a simplified wind farm model is conducted on four offshore wind fields data sets, two from lidar measurements and two from LES under unstable and neutral atmospheric conditions. The integral length scales of the horizontal wind speed computed in the streamwise and the cross-stream direction revealed the elongation of the structures in the direction of the mean flow. To analyse the effect of the structures on the power output of a wind turbine, the aggregated equivalent power of two wind turbines with different turbine spacing in the streamwise and cross-stream direction is analysed at different time scales under 10 minutes. The fact of considering the summation of the power of two wind turbines smooths out the fluctuations of the power output of a single wind turbine. This effect, which is stronger with increasing spacing between turbines, can be seen in the aggregation of the power of two wind turbines in the streamwise direction. Due to the anti-correlation of the coherent structures in the cross-stream direction, this smoothing effect is stronger when the aggregated power is computed with two wind turbines aligned orthogonally to the mean flow direction.

Frequency Domain Decomposition performed on the strain data obtained from the aluminium model of an offshore support structure

NASA Astrophysics Data System (ADS)

Mieloszyk, M.; Opoka, S.; Ostachowicz, W.

2015-07-01

This paper presents an application of Fibre Bragg Grating (FBG) sensors for Structural Health Monitoring (SHM) of offshore wind energy support structure model. The analysed structure is a tripod equipped with 16 FBG sensors. From a wide variety of Operational Modal Analysis (OMA) methods Frequency Domain Decomposition (FDD) technique is used in this paper under assumption that the input loading is similar to a white noise excitation. The FDD method can be applied using different sets of sensors, i.e. the one which contains all FBG sensors and the other set of sensors localised only on a particular tripod's leg. The cases considered during investigation were as follows: damaged and undamaged scenarios, different support conditions. The damage was simulated as an dismantled flange on an upper brace in one of the tripod legs. First the model was fixed to an antishaker table and investigated in the air under impulse excitations. Next the tripod was submerged into water basin in order to check the quality of the measurement set-up in different environmental condition. In this case the model was excited by regular waves.

Structural styles of the western onshore and offshore termination of the High Atlas, Morocco

NASA Astrophysics Data System (ADS)

Hafid, Mohamad; Zizi, Mahmoud; Bally, Albert W.; Ait Salem, Abdellah

2006-01-01

The present work aims (1) at documenting, by regional seismic transects, how the structural style varies in the western High Atlas system and its prolongation under the present-day Atlantic margin, (2) at understanding how this variation is related to the local geological framework, especially the presence of salt within the sedimentary cover, and (3) at discussing the exact geographic location of the northern front of the western High Atlas and how it links with the most western Atlas front in the offshore Cap Tafelney High Atlas. Previous work showed that the structural style of the Atlas belt changes eastward from a dominantly thick-skinned one in central and eastern High Atlas and Middle Atlas of Morocco to a dominantly thin-skinned one in Algeria and Tunisia. We propose here to show that a similar structural style change can be observed in the other direction of the Atlas Belt within its western termination, where the western High Atlas intersects at right angle the Atlantic passive margin and develops into a distinct segment, namely the High Atlas of Cap Tafelney, where salt/evaporite-based décollement tectonics prevail. To cite this article: M. Hafid et al., C. R. Geoscience 338 (2006).

Mineralogy and chemistry of Rumuruti: The first meteorite fall of the new R chondrite group

NASA Astrophysics Data System (ADS)

Schulze, H.; Bischoff, A.; Palme, H.; Spettel, B.; Dreibus, G.; Otto, J.

1994-03-01

The Rumuruti meteorite shower fell in Rumuruti, Kenya, on 1934 January 28 at 10:45 p.m. Rumuruti is an olivine-rich chondritic breccia with light-dark structure. Based on the coexistence of highly recrystallized fragments and unequilibrated components, Rumuruti is classified as a type 3-6 chondrite breccia. The most abundant phase of Rumuruti is olivine (mostly Fa(approximately 39) with about 70 vol%. Feldspar (approximately 14 vol%; mainly plagioclase), Ca-pyroxene (5 vol%), pyrrhotite (4.4 vol%), and pentlandite (3.6 vol%) are major constituents. All other phases have abundances below 1 vol%, including low-Ca pyroxene, chrome spinels, phosphates (chlorapatite and whitlockite), chalcopyrite, ilemenite, tridymite, Ni-rich and Ge-containing metals, kamacite, and various particles enriched in noble metals like Pt, Ir, and Au. The chemical composition of Rumuruti is chondritic. The depletion in refractory elements (Sc, REE, etc.) and the comparatively high Mn, Na, and K contents are characteristic of ordinary chondrites and distinguish Rumuruti from carbonaceous chondrites. However, S, Se, and Zn contents in Rumuruti are significantly above the level expected for ordinary chondrites. The oxygen isotope composition of Rumuruti is high in delta O-17 (5.52%) and delta O-18 (5.07%). With Rumuruti, nine meteorites samples exist that are chemically and mineralogically very similar. These meteorites are attributed to at least eight different fall events. It is proposed in this paper to call this group R chondrites (rumurutites) after the first and only fall among these meteorites. The meteorites have a close relationship to ordinary chondrites. However, they are more oxidized than any of the existing groups of ordinary chondrites. Small, but significant differences in chemical composition and in oxygen isotopes between R chondrites and ordinary chondrites exclude formation of R chondrites from ordinary chondrites by oxidation. This implies a separate, independent R chondrite parent body.

Experimental studies on equilibrium adsorption isosteres and determination of the thermodynamic quantities of polar media on alumina Al2O3

NASA Astrophysics Data System (ADS)

Yonova, Albena

2017-03-01

The present work is a revieif of theoretical and experimental study on the adsorption performance of the adsorbent Alumina (Al2O3) used in the adsorption system. An experimental investigation on the equilibrium adsorption isosteres at low pressure (< 1 atm) of working pairs Al2O3/H2O and Al2O3/C2H6O2 is carried out. The isovolume measurement method is adopted in the test setup to directly measure the saturated vapor pressures of working pairs at vapor-liquid equilibrium (dG=0 and dμi=0). Quantity adsorbed is determined from pressure, volume and temperature using gas law. The isosteric heat of adsorption is calculated from the slope of the plot of lnP versus 1/T different amounts of adsorbate onto adsorbent as follows: 0,01 vol% Al2O3/H2O; 0,03 vol% Al2O3/H2O; 0,1 vol% Al2O3/H2O; 0,01 vol% Al2O3/C2H6O2; 0,03 vol% Al2O3/C2H6O2; 0,1 vol% Al2O3/C2H6O2. This study shows that adsorption working pair Al2O3 C2H6O2 has better adsorption performances than those of the A2O3/H2O. Surface acidity! is a most important property! far both adsorption and catalysis and therefore is examined structure of active sites of alumina surface. Thermodynamic parameters such as isosteric heat of adsorption, isosteric enthalpy and entropy of adsorption are critical design variables in estimating the performance and predicting the mechanism of an adsorption process and are also one of the basic requirements for the characterization and optimization of an adsorption process

Sea Spray and Icing in the Emerging Open Water of the Arctic Ocean

DTIC Science & Technology

2013-06-17

can create copious amounts of sea spray. We anticipate that structures placed in shallow water— wind turbines or drilling rigs, for instance— will...anticipate that structures placed in shallow water— wind turbines or drilling rigs, for instance—will, therefore, experience more episodes of freezing...concentrations of wind -generated sea spray and the resulting spray icing on offshore structures, such as wind turbines and exploration, drilling, and production

Distributed meandering waveguides (DMWs) for novel photonic circuits (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dag, Ceren B.; Anil, Mehmet Ali; Serpengüzel, Ali

2017-05-01

Meandering waveguide distributed feedback structures are novel integrated photonic lightwave and microwave circuit elements. Meandering waveguide distributed feedback structures with a variety of spectral responses can be designed for a variety of lightwave and microwave circuit element functions. Distributed meandering waveguide (DMW) structures [1] show a variety of spectral behaviors with respect to the number of meandering loop mirrors (MLMs) [2] used in their composition as well as their internal coupling constants (Cs). DMW spectral behaviors include Fano resonances, coupled resonator induced transparency (CRIT), notch, add-drop, comb, and hitless filters. What makes the DMW special is the self-coupling property intrinsic to the DMW's nature. The basic example of DMW's nature is motivated through the analogy between the so-called symmetric meandering resonator (SMR), which consists of two coupled MLMs, and the resonator enhanced Mach-Zehnder interferometer (REMZI) [3]. A SMR shows the same spectral characteristics of Fano resonances with its self-coupling property, similar to the single, distributed and binary self coupled optical waveguide (SCOW) resonators [4]. So far DMWs have been studied for their electric field intensity, phase [5] and phasor responses [6]. The spectral analysis is performed using the coupled electric field analysis and the generalization of single meandering loop mirrors to multiple meandering distributed feedback structures is performed with the transfer matrix method. The building block of the meandering waveguide structures, the meandering loop mirror (MLM), is the integrated analogue of the fiber optic loop mirrors. The meandering resonator (MR) is composed of two uncoupled MLM's. The meandering distributed feedback (MDFB) structure is the DFB of the MLM. The symmetric MR (SMR) is composed of two coupled MLM's, and has the characteristics of a Fano resonator in the general case, and tunable power divider or tunable hitless filter in special cases. The antisymmetric MR (AMR) is composed of two coupled MLM's. The AMR has the characteristics of an add-drop filter in the general case, and coupled resonator induced transparency (CRIT) filter in a special case. The symmetric MDFB (SMDFB) is composed of multiple coupled MLM's. The antisymmetric MDFB (AMDFB) is composed of multiple coupled MLM's. The SMDFB and AMDFB can be utilized as band-pass, Fano, or Lorentzian filters, or Rabi splitters. Distributed meandering waveguide elements with extremely rich spectral and phase responses can be designed with creative combinations of distributed meandering waveguides structures for various novel photonic circuits. References [1 ] C. B. Dağ, M. A. Anıl, and A. Serpengüzel, "Meandering Waveguide Distributed Feedback Lightwave Circuits," J. Lightwave Technol, vol. 33, no. 9, pp. 1691-1702, May 2015. [2] N. J. Doran and D. Wood, "Nonlinear-optical loop mirror," Opt. Lett. vol. 13, no. 1, pp. 56-58, Jan. 1988. [3] L. Zhou and A. W. Poon, "Fano resonance-based electrically reconfigurable add-drop filters in silicon microring resonator-coupled Mach-Zehnder interferometers," Opt. Lett. vol. 32, no. 7, pp. 781-783, Apr. 2007. [4] Z. Zou, L. Zhou, X. Sun, J. Xie, H. Zhu, L. Lu, X. Li, and J. Chen, "Tunable two-stage self-coupled optical waveguide resonators," Opt. Lett. vol. 38, no. 8, pp. 1215-1217, Apr. 2013. [5] C. B. Dağ, M. A. Anıl, and A. Serpengüzel, "Novel distributed feedback lightwave circuit elements," in Proc. SPIE, San Francisco, 2015, vol. 9366, p. 93660A. [6] C. B. Dağ, M. A. Anıl, and A. Serpengüzel, "Meandering Waveguide Distributed Feedback Lightwave Elements: Phasor Diagram Analysis," in Proc. PIERS, Prague, 1986-1990 (2015).

Grouted pile to sleeves connections: Design provisions for the new ISO Standard for offshore structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harwood, R.G.; Billington, C.J.; Buitrago, J.

1996-12-01

A Technical Core Group (TCG) was set up in March 1994 to review the design practice provisions for grouted pile to sleeve connections, mechanical connections and repairs as part of the international harmonization process for the new ISO Standard, ISO 13819-2, Petroleum and Natural Gas Industries--Offshore Structures, Part 2: Fixed Steel Structures. This paper provides an overview of the development of the proposed new design provisions for grouted connections including, the gathering and screening of the data, the evolution of the design formulae, and the evaluation of the resistance factor. Detailed comparisons of the new formulae with current design practicemore » (API, HSE and DnV) are also included. In the development of the new provisions the TCG has been given access to the largest database ever assembled on this topic. This database includes all the major testing programs performed over the last 20 years, and recent UK and Norwegian research projects not previously reported. The limitations in the database are discussed and the areas where future research would be of benefit are highlighted.« less

The crustal structures from Wuyi-Yunkai orogen to Taiwan orogen: the onshore-offshore wide-angle seismic experiment of TAIGER and ATSEE projects

NASA Astrophysics Data System (ADS)

Kuochen, H.; Kuo, N. Y. W.; Wang, C. Y.; Jin, X.; Cai, H. T.; Lin, J. Y.; Wu, F. T.; Yen, H. Y.; Huang, B. S.; Liang, W. T.; Okaya, D. A.; Brown, L. D.

2015-12-01

The crustal structure is key information for understanding the tectonic framework and geological evolution in the southeastern China and its adjacent area. In this study, we integrated the data sets from the TAIGER and ATSEE projects to resolve onshore-offshore deep crustal seismic profiles from the Wuyi-Yunkai orogen to the Taiwan orogen in southeastern China. Totally, there are three seismic profiles resolved and the longest profile is 850 km. Unlike 2D and 3D first arrival travel-time tomography from previous studies, we used both refracted and reflected phases (Pg, Pn, PcP, and PmP) to model the crustal structures and the crustal reflectors. 40 shots, 2 earthquakes, and about 1,950 stations were used and 15,319 arrivals were picked among three transects. As a result, the complex crustal evolution since Paleozoic era are shown, which involved the closed Paleozoic rifted basin in central Fujian, the Cenozoic extension due to South China sea opening beneath the coastline of southern Fujian, and the on-going collision of the Taiwan orogen.

High resolution seismic reflection survey in the Gulf of Pozzuoli, Naples, Italy. An example of preliminary interpretation of seismic profiles.

NASA Astrophysics Data System (ADS)

D'Aniello, Elena; di Fiore, Vincenzo; Sacchi, Marco; Rapolla, Antonio

2010-05-01

During the cruise CAFE_07 - Leg 3 conducted in the Gulf of Naples and Pozzuoli in January 2008, on board of the R/V URANIA of the CNR it was carried out the acquisition of a grid of ca. 800 km of high-resolution multichannel reflection seismic profiles (Sacchi et al., 2009; Di Fiore et al., 2009). The aim of the cruise was the understanding of the stratigraphic-structural setting of the Pozzuoli Bay area, with specific reference to the major offshore volcanic features, such as Nisida Bank, Pentapalummo Bank, M.Dolce-Pampano Bank and Miseno Bank and others. The Gulf of Pozzuoli is placed in the Volcanic district of Campi Flegrei, an area of active volcanism located at North West of Naples city, along the Tyrrhenian margin, in an extensional collapsed area called Campanian Plain, filled by siliciclastic, epiclastic and volcaniclastic sediments, deposited during Late Pliocene and Quaternary. Several studies present in literature suggest a relation between volcanic system of Campi Flegrei and faults system; in particular, at the Gulf of Pozzuoli we can observe some volcanic banks and submarine volcanic edifices, as Pentapalummo, Nisida and Miseno Banks, are aligned along the NE-SW trending Magnaghi-Sebeto fault line, that separates the Bay of Naples into two sectors: the first, at NW of the Bay, characterized by volcanism activity and magnetic anomalies and the second, at SE of the bay, involved only by sedimentary activity, with the exceptions of the circular anomalies in the offshore of Torre del Greco city (Bruno et al., 2003; Secomandi et al., 2003); other volcanic hights are instead positioned along NW-SE structural discontinuities (Bruno, 2004). The magnetic and gravimetric analysis of the Bay of Naples confirms the tectonic control of the Campanian volcanism: we can observe a good correspondence of high magnetic anomalies with the main volcanic structures at the North-Western side of the bay, just the Gulf of Pozzuoli, where both NE-SW and NW-SE normal faults were recognized. The correspondence between magnetic structures, interpreted as volcanic bodies, and the faults NE-SW and NW-SE trending, supports the hypothesis that the magma rises along normal faults cutting the carbonate platform. We here present two significant seismic profiles: their interpretation reveals a complex stratigraphic and structural setting, dominated by the occurrence of volcanic bodies and siliciclastic depositional units, mostly deriving from the dismantling of the adjacent vents and volcaniclastic units. The results of this preliminary research include the recognition of volcanic features and structures not yet described in the literature that may represent a relevant contribute to the understanding of the Late Quaternary evolution of the Campi Flegrei area. References: Bruno P.P., Rapolla A., Di Fiore V., 2003. Structural setting of the Bay of Naples (Italy) seismic reflection data: implications for Campanian volcanism. Tectonophysics, 372, 193-213. Bruno P.P., 2004. Structure and evolution of the Bay of Pozzuoli (Italy) using marine seismic reflection data: implication for collapse of the Campi Flegrei caldera. Bull. Volcanol., 66, 342-355. Di Fiore V., D'Aniello E., Rapolla A., Sacchi M., Secomandi M., Spiess V., 2009. Multichannel seismic survey in coastal Campania area by two different resolution sources. EGU General Assembly 2009, vol.11. Sacchi M., Alessio G., Aquino I., Esposito E., Molisso F., Nappi R., Porfido S., Violante C., 2008. Risultati preliminari della campagna oceanografica CAFE_07 - Leg 3 nei Golfi di Napoli e Pozzuoli, Mar Tirreno Orientale. Quaderni di Geofisica, n. 64. Secomandi M., Paoletti V., Aiello G., Fedi M., Marsella E., Ruggieri S., D'Argenio B., Rapolla A., 2003. Analysis of the magnetic anomaly field of the volcanic district of the Bay of Naples, Italy. Marine Geophysical Researches. 24: 207-221.

75 FR 76453 - Columbia Gulf Transmission Company and Southern Natural Gas Company; Notice of Intent to Prepare...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-08

... workspaces) at three discrete onshore and offshore locations: One 60-foot by 20-foot excavation area within... district, site, building, structure, or object included in or eligible for inclusion in the National...

30 CFR 250.915 - What are the CVA's primary responsibilities?

Code of Federal Regulations, 2010 CFR

2010-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Platforms and Structures... or organizations acting as CVAs must not function in any capacity that would create a conflict of... design, fabrication and installation of the platform. ...

Offshore Wind Energy Resource Assessment for Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doubrawa Moreira, Paula; Scott, George N.; Musial, Walter D.

This report quantifies Alaska's offshore wind resource capacity while focusing on its unique nature. It is a supplement to the existing U.S. Offshore Wind Resource Assessment, which evaluated the offshore wind resource for all other U.S. states. Together, these reports provide the foundation for the nation's offshore wind value proposition. Both studies were developed by the National Renewable Energy Laboratory. The analysis presented herein represents the first quantitative evidence of the offshore wind energy potential of Alaska. The technical offshore wind resource area in Alaska is larger than the technical offshore resource area of all other coastal U.S. states combined.more » Despite the abundant wind resource available, significant challenges inhibit large-scale offshore wind deployment in Alaska, such as the remoteness of the resource, its distance from load centers, and the wealth of land available for onshore wind development. Throughout this report, the energy landscape of Alaska is reviewed and a resource assessment analysis is performed in terms of gross and technical offshore capacity and energy potential.« less

Simulation-based optimization of lattice support structures for offshore wind energy converters with the simultaneous perturbation algorithm

NASA Astrophysics Data System (ADS)

Molde, H.; Zwick, D.; Muskulus, M.

2014-12-01

Support structures for offshore wind turbines are contributing a large part to the total project cost, and a cost saving of a few percent would have considerable impact. At present support structures are designed with simplified methods, e.g., spreadsheet analysis, before more detailed load calculations are performed. Due to the large number of loadcases only a few semimanual design iterations are typically executed. Computer-assisted optimization algorithms could help to further explore design limits and avoid unnecessary conservatism. In this study the simultaneous perturbation stochastic approximation method developed by Spall in the 1990s was assessed with respect to its suitability for support structure optimization. The method depends on a few parameters and an objective function that need to be chosen carefully. In each iteration the structure is evaluated by time-domain analyses, and joint fatigue lifetimes and ultimate strength utilization are computed from stress concentration factors. A pseudo-gradient is determined from only two analysis runs and the design is adjusted in the direction that improves it the most. The algorithm is able to generate considerably improved designs, compared to other methods, in a few hundred iterations, which is demonstrated for the NOWITECH 10 MW reference turbine.

Microelectrodes with Three-Dimensional Structures for Improved Neural Interfacing

DTIC Science & Technology

2001-10-25

highly xible bio-interfaces [2]. Polyimides combine excellent ectrical and mechanical characteristics with biocompatibility ], and are well known in...excellent biocompatibility , polyimide -based electrodes promise for fabrication of long-term implants for the use in prostheses. The flexible structures...R. R. Richardson, J. A. Miller, and W. M. Reichert, " Polyimides as Biomaterials - Preliminary Biocompatibility Testing," Biomaterials, vol. 14, pp

Assessing the effects of catch and release regulations on a quality adfluvial brook trout population using a computer based age-structure model

USGS Publications Warehouse

Risley, Casey A.L.; Zydlewski, Joseph D.

2011-01-01

Assessing the Effects of Catch-and-Release Regulations on a Brook Trout Population Using an Age-Structured Model: North American Journal of Fisheries Management: Vol 30, No 6 var _prum=[['id','54ff88bcabe53dc41d1004a5'],['mark','firstbyte',(new Date()).getTime()

Solidification of Magnesium (AM50A) / vol%. SiCp composite

NASA Astrophysics Data System (ADS)

Zhang, X.; Hu, H.

2012-01-01

Magnesium matrix composite is one of the advanced lightweight materials with high potential to be used in automotive and aircraft industries due to its low density and high specific mechanical properties. The magnesium composites can be fabricated by adding the reinforcements of fibers or/and particles. In the previous literature, extensive studies have been performed on the development of matrix grain structure of aluminum-based metal matrix composites. However, there is limited information available on the development of grain structure during the solidification of particulate-reinforced magnesium. In this work, a 5 vol.% SiCp particulate-reinforced magnesium (AM50A) matrix composite (AM50A/SiCp) was prepared by stir casting. The solidification behavior of the cast AM50A/SiCp composite was investigated by computer-based thermal analysis. Optical and scanning electron microscopies (SEM) were employed to examine the occurrence of nucleation and grain refinement involved. The results indicate that the addition of SiCp particulates leads to a finer grain structure in the composite compared with the matrix alloy. The refinement of grain structure should be attributed to both the heterogeneous nucleation and the restricted primary crystal growth.

A new submarine oil-water separation system

NASA Astrophysics Data System (ADS)

Cai, Wen-Bin; Liu, Bo-Hong

2017-12-01

In order to solve the oil field losses of environmental problems and economic benefit caused by the separation of lifting production liquid to offshore platforms in the current offshore oil production, from the most basic separation principle, a new oil-water separation system has been processed of adsorption and desorption on related materials, achieving high efficiency and separation of oil and water phases. And the submarine oil-water separation device has been designed. The main structure of the device consists of gas-solid phase separation device, period separating device and adsorption device that completed high efficiency separation of oil, gas and water under the adsorption and desorption principle, and the processing capacity of the device is calculated.

Investigation of the fluid flow dynamic parameters for Newtonian and non-Newtonian materials: an approach to understanding the fluid flow-like structures within fault zones

NASA Astrophysics Data System (ADS)

Tanaka, H.; Shiomi, Y.; Ma, K.-F.

2017-11-01

To understand the fault zone fluid flow-like structure, namely the ductile deformation structure, often observed in the geological field (e.g., Ramsay and Huber The techniques of modern structure geology, vol. 1: strain analysis, Academia Press, London, 1983; Hobbs and Ord Structure geology: the mechanics of deforming metamorphic rocks, Vol. I: principles, Elsevier, Amsterdam, 2015), we applied a theoretical approach to estimate the rate of deformation, the shear stress and the time to form a streak-line pattern in the boundary layer of viscous fluids. We model the dynamics of streak lines in laminar boundary layers for Newtonian and pseudoplastic fluids and compare the results to those obtained via laboratory experiments. The structure of deformed streak lines obtained using our model is consistent with experimental observations, indicating that our model is appropriate for understanding the shear rate, flow time and shear stress based on the profile of deformed streak lines in the boundary layer in Newtonian and pseudoplastic viscous materials. This study improves our understanding of the transportation processes in fluids and of the transformation processes in fluid-like materials. Further application of this model could facilitate understanding the shear stress and time history of the fluid flow-like structure of fault zones observed in the field.[Figure not available: see fulltext.

Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California

USGS Publications Warehouse

Ryan, H.F.; Parsons, T.; Sliter, R.W.

2008-01-01

A new fault map of the shelf offshore of San Francisco, California shows that faulting occurs as a distributed shear zone that involves many fault strands with the principal displacement taken up by the San Andreas fault and the eastern strand of the San Gregorio fault zone. Structures associated with the offshore faulting show compressive deformation near where the San Andreas fault goes offshore, but deformation becomes extensional several km to the north off of the Golden Gate. Our new fault map serves as the basis for a 3-D finite element model that shows that the block between the San Andreas and San Gregorio fault zone is subsiding at a long-term rate of about 0.2-0.3??mm/yr, with the maximum subsidence occurring northwest of the Golden Gate in the area of a mapped transtensional basin. Although the long-term rates of vertical displacement primarily show subsidence, the model of coseismic deformation associated with the 1906 San Francisco earthquake indicates that uplift on the order of 10-15??cm occurred in the block northeast of the San Andreas fault. Since 1906, 5-6??cm of regional subsidence has occurred in that block. One implication of our model is that the transfer of slip from the San Andreas fault to a fault 5??km to the east, the Golden Gate fault, is not required for the area offshore of San Francisco to be in extension. This has implications for both the deposition of thick Pliocene-Pleistocene sediments (the Merced Formation) observed east of the San Andreas fault, and the age of the Peninsula segment of the San Andreas fault.

Observations of internal bores and waves of elevation on the New England inner continental shelf during summer 2001

NASA Astrophysics Data System (ADS)

Pritchard, Mark; Weller, Robert A.

2005-03-01

During July-August 2001, oceanographic variability on the New England inner continental shelf was investigated with an emphasis on temporal scales shorter than tidal periods. Mooring and ship survey data showed that subtidal variation of inner shelf stratification was in response to regional Ekman upwelling and downwelling wind driven dynamics. High-frequency variability in the vertical structure of the water column at an offshore mooring site was linked to the baroclinic internal tide and the onshore propagation of nonlinear solitary waves of depression. Temperature, salinity, and velocity data measured at an inshore mooring detected a bottom bore that formed on the flood phase of the tide. During the ebb tide, a second bottom discontinuity and series of nonlinear internal waves of elevation (IWOE) formed when the water column became for a time under hydraulic control. A surface manifestation of these internal wave crests was also observed in aircraft remote sensing imagery. The coupling of IWOE formation to the offshore solitary waves packets was investigated through internal wave breaking criterion derived in earlier laboratory studies. Results suggested that the offshore solitons shoaled on the sloping shelf, and transformed from waves of depression to waves of elevation. The coupling of inshore bore formation to the offshore solitary waves and the possible impact of these periodic features on mixing on the inner shelf region are discussed.

Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 5 - Structural dynamics and aeroelasticity

NASA Technical Reports Server (NTRS)

Noor, Ahmed K. (Editor); Venneri, Samuel L. (Editor)

1993-01-01

Various papers on flight vehicle materials, structures, and dynamics are presented. Individual topics addressed include: general modeling methods, component modeling techniques, time-domain computational techniques, dynamics of articulated structures, structural dynamics in rotating systems, structural dynamics in rotorcraft, damping in structures, structural acoustics, structural design for control, structural modeling for control, control strategies for structures, system identification, overall assessment of needs and benefits in structural dynamics and controlled structures. Also discussed are: experimental aeroelasticity in wind tunnels, aeroservoelasticity, nonlinear aeroelasticity, aeroelasticity problems in turbomachines, rotary-wing aeroelasticity with application to VTOL vehicles, computational aeroelasticity, structural dynamic testing and instrumentation.

77 FR 70172 - Lifesaving and Fire-Fighting Equipment, Training and Drills Onboard Offshore Facilities and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-23

... Equipment, Training and Drills Onboard Offshore Facilities and Mobile Offshore Drilling Units (MODUs... lifesaving and fire-fighting equipment, training and drills on board offshore facilities and MODUs operating... guidance concerning lifesaving and fire-fighting equipment, training, and drills onboard manned offshore...

Atmospheric Characterization of the US Offshore Sites and Impact on Turbine Performance (Poster)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arora, Dhiraj; Ehrmann, Robert; Zuo, Delong

Reliable, long term offshore atmospheric data is critical to development of the US offshore wind industry. There exists significant lack of meteorological, oceanographic, and geological data at potential US offshore sites. Assessment of wind resources at heights in the range of 25-200m is needed to understand and characterize offshore wind turbine performance. Data from the US Department of Energy owned WindSentinel buoy from two US offshore sites and one European site is analyzed. Low Level Jet (LLJ) phenomena and its potential impact on the performance of an offshore wind turbine is investigated.

Synthesis of ceramic-based porous gradient structures for applications in energy conversion and related fields

NASA Astrophysics Data System (ADS)

Graule, Thomas; Ozog, Paulina; Durif, Caroline; Wilkens-Heinecke, Judit; Kata, Dariusz

2016-06-01

Porous, graded ceramic structures are of high relevance in the field of energy conversion as well as in catalysis, and additionally in filtration technology and in biomedical applications. Among different technologies for the tailored design for such structures we demonstrate here a new environmental friendly UV curing-based concept to prepare laminated structures with pore sizes ranging from a few microns up to 50 microns in diameter and with porosities ranging from 10% up to 75 vol.% porosity.

Structures and geriatrics from a failure analysis experience viewpoint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopper, D.M.

In a failure analysis consulting engineering practice one sees a variety of structural failures from which observations may be made concerning geriatric structures. Representative experience with power plants, refineries, offshore structures, and forensic investigations is summarized and generic observations are made regarding the maintenance of fitness for purpose of structures. Although it is important to optimize the engineering design for a range of operational and environmental variables, it is essential that fabrication and inspection controls exist along with common sense based ongoing monitoring and operations procedures. 18 figs.

LOOP marine and estuarine monitoring program, 1978-95 : volume 4 : zooplankton and ichthyoplankton.

DOT National Transportation Integrated Search

1998-01-01

The Louisiana Offshore Oil Port (LOOP) facilities in coastal Louisiana provide the United States with the country's only Superport for off-loading deep draft tankers. The three single-point mooring (SPM) structures connected by pipelines to a platfor...

50 CFR 216.214 - Prohibitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS Taking of Marine Mammals Incidental to Explosive Severance Activities Conducted During Offshore Structure Removal Operations on the Outer Continental Shelf in the U.S. Gulf of Mexico § 216.214 Prohibitions. No...

Fair shares: a preliminary framework and case analyzing the ethics of offshoring.

PubMed

Gordon, Cameron; Zimmerman, Alan

2010-06-01

Much has been written about the offshoring phenomenon from an economic efficiency perspective. Most authors have attempted to measure the net economic effects of the strategy and many purport to show that "in the long run" that benefits will outweigh the costs. There is also a relatively large literature on implementation which describes the best way to manage the offshoring process. But what is the morality of offshoring? What is its "rightness" or "wrongness?" Little analysis of the ethics of offshoring has been completed thus far. This paper develops a preliminary framework for analyzing the ethics of offshoring and then applies this framework to basic case study of offshoring in the U.S. The paper following discusses the definition of offshoring; shifts to the basic philosophical grounding of the ethical concepts; develops a template for conducting an ethics analysis of offshoring; applies this template using basic data for offshoring in the United States; and conducts a preliminary ethical analysis of the phenomenon in that country, using a form of utilitarianism as an analytical baseline. The paper concludes with suggestions for further research.

Tubular solid oxide fuel cells with porous metal supports and ceramic interconnections

DOEpatents

Huang, Kevin [Export, PA; Ruka, Roswell J [Pittsburgh, PA

2012-05-08

An intermediate temperature solid oxide fuel cell structure capable of operating at from 600.degree. C. to 800.degree. C. having a very thin porous hollow elongated metallic support tube having a thickness from 0.10 mm to 1.0 mm, preferably 0.10 mm to 0.35 mm, a porosity of from 25 vol. % to 50 vol. % and a tensile strength from 700 GPa to 900 GPa, which metallic tube supports a reduced thickness air electrode having a thickness from 0.010 mm to 0.2 mm, a solid oxide electrolyte, a cermet fuel electrode, a ceramic interconnection and an electrically conductive cell to cell contact layer.

Optimized Generator Designs for the DTU 10-MW Offshore Wind Turbine using GeneratorSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sethuraman, Latha; Maness, Michael; Dykes, Katherine

Compared to land-based applications, offshore wind imposes challenges for the development of next generation wind turbine generator technology. Direct-drive generators are believed to offer high availability, efficiency, and reduced operation and maintenance requirements; however, previous research suggests difficulties in scaling to several megawatts or more in size. The resulting designs are excessively large and/or massive, which are major impediments to transportation logistics, especially for offshore applications. At the same time, geared wind turbines continue to sustain offshore market growth through relatively cheaper and lightweight generators. However, reliability issues associated with mechanical components in a geared system create significant operation andmore » maintenance costs, and these costs make up a large portion of overall system costs offshore. Thus, direct-drive turbines are likely to outnumber their gear-driven counterparts for this market, and there is a need to review the costs or opportunities of building machines with different types of generators and examining their competitiveness at the sizes necessary for the next generation of offshore wind turbines. In this paper, we use GeneratorSE, the National Renewable Energy Laboratory's newly developed systems engineering generator sizing tool to estimate mass, efficiency, and the costs of different generator technologies satisfying the electromagnetic, structural, and basic thermal design requirements for application in a very large-scale offshore wind turbine such as the Technical University of Denmark's (DTU) 10-MW reference wind turbine. For the DTU reference wind turbine, we use the previously mentioned criteria to optimize a direct-drive, radial flux, permanent-magnet synchronous generator; a direct-drive electrically excited synchronous generator; a medium-speed permanent-magnet generator; and a high-speed, doubly-fed induction generator. Preliminary analysis of leveled costs of energy indicate that for large turbines, the cost of permanent magnets and reliability issues associated with brushes in electrically excited machines are the biggest deterrents for building direct-drive systems. The advantage of medium-speed permanent-magnet machines over doubly-fed induction generators is evident, yet, variability in magnet prices and solutions to address reliability issues associated with gearing and brushes can change this outlook. This suggests the need to potentially pursue fundamentally new innovations in generator designs that help avoid high capital costs but still have significant reliability related to performance.« less

Optimized Generator Designs for the DTU 10-MW Offshore Wind Turbine using GeneratorSE: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sethuraman, Latha; Maness, Michael; Dykes, Katherine

Compared to land-based applications, offshore wind imposes challenges for the development of next generation wind turbine generator technology. Direct-drive generators are believed to offer high availability, efficiency, and reduced operation and maintenance requirements; however, previous research suggests difficulties in scaling to several megawatts or more in size. The resulting designs are excessively large and/or massive, which are major impediments to transportation logistics, especially for offshore applications. At the same time, geared wind turbines continue to sustain offshore market growth through relatively cheaper and lightweight generators. However, reliability issues associated with mechanical components in a geared system create significant operation andmore » maintenance costs, and these costs make up a large portion of overall system costs offshore. Thus, direct-drive turbines are likely to outnumber their gear-driven counterparts for this market, and there is a need to review the costs or opportunities of building machines with different types of generators and examining their competitiveness at the sizes necessary for the next generation of offshore wind turbines. In this paper, we use GeneratorSE, the National Renewable Energy Laboratory's newly developed systems engineering generator sizing tool to estimate mass, efficiency, and the costs of different generator technologies satisfying the electromagnetic, structural, and basic thermal design requirements for application in a very large-scale offshore wind turbine such as the Technical University of Denmark's (DTU) 10-MW reference wind turbine. For the DTU reference wind turbine, we use the previously mentioned criteria to optimize a direct-drive, radial flux, permanent-magnet synchronous generator; a direct-drive electrically excited synchronous generator; a medium-speed permanent-magnet generator; and a high-speed, doubly-fed induction generator. Preliminary analysis of leveled costs of energy indicate that for large turbines, the cost of permanent magnets and reliability issues associated with brushes in electrically excited machines are the biggest deterrents for building direct-drive systems. The advantage of medium-speed permanent-magnet machines over doubly-fed induction generators is evident, yet, variability in magnet prices and solutions to address reliability issues associated with gearing and brushes can change this outlook. This suggests the need to potentially pursue fundamentally new innovations in generator designs that help avoid high capital costs but still have significant reliability related to performance.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Xiao-Dong; Xu, Yun-Bo, E-mail: yunbo_xu@126.com; Yang, Xiao-Long

Microstructures composed of lath martensite and retained austenite with volume fraction between 8.0 vol.% and 12.0 vol.% were obtained in a low-C low-Si Al-free steel through hot-rolling direct quenching and dynamical partitioning (HDQ&DP) processes. The austenite stabilization mechanism in the low-C low-Si Al-free steel under the special dynamical partitioning processes is investigated by analyzing the carbon partition behavior from martensite to austenite and the carbide precipitation-coarsening behavior in martensite laths combining with the possible hot rolling deformation inheritance. Results show that the satisfying retained austenite amount in currently studied low-Si Al-free HDQ&DP steel is caused by the high-efficiency carbon enrichmentmore » in the 30–80 nm thick regions of austenite near the interfaces in the hot-rolled ultra-fast cooled structure and the avoidance of serious carbides coarsening during the continuous cooling procedures. The excellent strength-elongation product reaching up to 26,000 MPa% shows that the involved HDQ&DP process is a promising method to develop a new generation of advanced high strength steel. - Highlights: • HDQ&DP processes were applied to a low-C low-Si Al-free steel. • Effective partitioning time during the continuous cooling processes is 1–220 s. • Retained austenite with volume fraction between 8.0 vol. % and 12.0 vol. % has been obtained. • The special austenite stabilization mechanism has been expounded.« less

Towards sustainable fishery management for skates in South America: The genetic population structure of Zearaja chilensis and Dipturus trachyderma (Chondrichthyes, Rajiformes) in the south-east Pacific Ocean.

PubMed

Vargas-Caro, Carolina; Bustamante, Carlos; Bennett, Michael B; Ovenden, Jennifer R

2017-01-01

The longnose skates (Zearaja chilensis and Dipturus trachyderma) are the main component of the elasmobranch fisheries in the south-east Pacific Ocean. Both species are considered to be a single stock by the fishery management in Chile however, little is known about the level of demographic connectivity within the fishery. In this study, we used a genetic variation (560 bp of the control region of the mitochondrial genome and ten microsatellite loci) to explore population connectivity at five locations along the Chilean coast. Analysis of Z. chilensis populations revealed significant genetic structure among off-shore locations (San Antonio, Valdivia), two locations in the Chiloé Interior Sea (Puerto Montt and Aysén) and Punta Arenas in southern Chile. For example, mtDNA haplotype diversity was similar across off-shore locations and Punta Arenas (h = 0.46-0.50), it was significantly different to those in the Chiloé Interior Sea (h = 0.08). These results raise concerns about the long-term survival of the species within the interior sea, as population resilience will rely almost exclusively on self-recruitment. In contrast, little evidence of genetic structure was found for D. trachyderma. Our results provide evidence for three management units for Z. chilensis, and we recommend that separate management arrangements are required for each of these units. However, there is no evidence to discriminate the extant population of Dipturus trachyderma as separate management units. The lack of genetic population subdivision for D. trachyderma appears to correspond with their higher dispersal ability and more offshore habitat preference.

Study of crustal structure and stretch mechanism of central continental shelf of northern South China Sea

NASA Astrophysics Data System (ADS)

Cao, J.; Xia, S.; Sun, J.; Wan, K.; Xu, H.

2017-12-01

Known as a significant region to study tectonic relationship between South China block and South China Sea (SCS) block and the evolution of rifted basin in continental margin, the continental shelf of northern SCS documents the evolution from continental splitting to seafloor spreading of SCS. To investigate crustal structure of central continental shelf in northern SCS, two wide-angle onshore-offshore seismic experiments and coincident multi-channel seismic (MCS) profiles were carried out across the onshore-offshore transitional zone in northern SCS, 2010 and 2012. A total of 34 stations consisted of ocean bottom seismometers, portable and permanent land stations were deployed during the survey. The two-dimensional precise crustal structure models of central continental shelf in northern SCS was constructed from onshore to offshore, and the stretching factors along the P-wave velocity models were calculated. The models reveal that South China block is a typical continental crust with a 30-32 km Moho depth, and a localized high-velocity anomaly in middle-lower crust under land area near Hong Kong was imaged, which may reflect magma underplating caused by subduction of paleo-Pacific plate in late Mesozoic. The littoral fault zone is composed of several parallel, high-angle, normal faults that mainly trend northeast to northeast-to-east and dip to the southeast with a large displacement, and the fault is divided into several segments separated by the northwest-trending faults. The shelf zone south of LFZ was consisted of a differential thinning upper and lower continental crust, which indicate stretch thinning of passive continent margin during the Cenozoic spreading of the SCS. The results appear to further confirm that the northern margin of SCS experienced a transition from active margin to passive one during late Mesozoic and Cenozoic.

Considerations in evaluating potential socioeconomic impacts of offshore platform decommissioning in California.

PubMed

Kruse, Sarah A; Bernstein, Brock; Scholz, Astrid J

2015-10-01

The 27 oil and gas platforms offshore southern California will eventually reach the end of their useful lifetimes (estimated between 2015 and 2030) and will be decommissioned. Current state and federal laws and regulations allow for alternative uses in lieu of the complete removal required in existing leases. Any decommissioning pathway will create a complex mix of costs, benefits, opportunities, and constraints for multiple user groups. To assist the California Natural Resources Agency in understanding these issues, we evaluated the potential socioeconomic impacts of the 2 most likely options: complete removal and partial removal of the structure to 85 feet below the waterline with the remaining structure left in place as an artificial reef-generally defined as a manmade structure with some properties that mimic a natural reef. We estimated impacts on commercial fishing, commercial shipping, recreational fishing, nonconsumptive boating, and nonconsumptive SCUBA diving. Available data supported quantitative estimates for some impacts, semiquantitative estimates for others, and only qualitative approximations of the direction of impact for still others. Even qualitative estimates of the direction of impacts and of user groups' likely preferred options have been useful to the public and decision makers and provided valuable input to the project's integrative decision model. Uncertainty surrounds even qualitative estimates of the likely direction of impact where interactions between multiple impacts could occur or where user groups include subsets that would experience the same option differently. In addition, we were unable to quantify effects on ecosystem value and on the larger regional ecosystem, because of data gaps on the population sizes and dynamics of key species and the uncertainty surrounding the contribution of platforms to available hard substrate and related natural populations offshore southern California. © 2015 SETAC.

Crustal structure and fault geometry of the 2010 Haiti earthquake from temporary seismometer deployments

USGS Publications Warehouse

Douilly, Roby; Haase, Jennifer S.; Ellsworth, William L.; Bouin, Marie‐Paule; Calais, Eric; Symithe, Steeve J.; Armbruster, John G.; Mercier de Lépinay, Bernard; Deschamps, Anne; Mildor, Saint‐Louis; Meremonte, Mark E.; Hough, Susan E.

2013-01-01

Haiti has been the locus of a number of large and damaging historical earthquakes. The recent 12 January 2010 Mw 7.0 earthquake affected cities that were largely unprepared, which resulted in tremendous losses. It was initially assumed that the earthquake ruptured the Enriquillo Plantain Garden fault (EPGF), a major active structure in southern Haiti, known from geodetic measurements and its geomorphic expression to be capable of producing M 7 or larger earthquakes. Global Positioning Systems (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data, however, showed that the event ruptured a previously unmapped fault, the Léogâne fault, a north‐dipping oblique transpressional fault located immediately north of the EPGF. Following the earthquake, several groups installed temporary seismic stations to record aftershocks, including ocean‐bottom seismometers on either side of the EPGF. We use data from the complete set of stations deployed after the event, on land and offshore, to relocate all aftershocks from 10 February to 24 June 2010, determine a 1D regional crustal velocity model, and calculate focal mechanisms. The aftershock locations from the combined dataset clearly delineate the Léogâne fault, with a geometry close to that inferred from geodetic data. Its strike and dip closely agree with the global centroid moment tensor solution of the mainshock but with a steeper dip than inferred from previous finite fault inversions. The aftershocks also delineate a structure with shallower southward dip offshore and to the west of the rupture zone, which could indicate triggered seismicity on the offshore Trois Baies reverse fault. We use first‐motion focal mechanisms to clarify the relationship of the fault geometry to the triggered aftershocks.

Towards sustainable fishery management for skates in South America: The genetic population structure of Zearaja chilensis and Dipturus trachyderma (Chondrichthyes, Rajiformes) in the south-east Pacific Ocean

PubMed Central

Bustamante, Carlos; Bennett, Michael B.; Ovenden, Jennifer R.

2017-01-01

The longnose skates (Zearaja chilensis and Dipturus trachyderma) are the main component of the elasmobranch fisheries in the south-east Pacific Ocean. Both species are considered to be a single stock by the fishery management in Chile however, little is known about the level of demographic connectivity within the fishery. In this study, we used a genetic variation (560 bp of the control region of the mitochondrial genome and ten microsatellite loci) to explore population connectivity at five locations along the Chilean coast. Analysis of Z. chilensis populations revealed significant genetic structure among off-shore locations (San Antonio, Valdivia), two locations in the Chiloé Interior Sea (Puerto Montt and Aysén) and Punta Arenas in southern Chile. For example, mtDNA haplotype diversity was similar across off-shore locations and Punta Arenas (h = 0.46–0.50), it was significantly different to those in the Chiloé Interior Sea (h = 0.08). These results raise concerns about the long-term survival of the species within the interior sea, as population resilience will rely almost exclusively on self-recruitment. In contrast, little evidence of genetic structure was found for D. trachyderma. Our results provide evidence for three management units for Z. chilensis, and we recommend that separate management arrangements are required for each of these units. However, there is no evidence to discriminate the extant population of Dipturus trachyderma as separate management units. The lack of genetic population subdivision for D. trachyderma appears to correspond with their higher dispersal ability and more offshore habitat preference. PMID:28207832

Diagnosis of an intense atmospheric river impacting the pacific northwest: Storm summary and offshore vertical structure observed with COSMIC satellite retrievals

USGS Publications Warehouse

Neiman, P.J.; Ralph, F.M.; Wick, G.A.; Kuo, Y.-H.; Wee, T.-K.; Ma, Z.; Taylor, G.H.; Dettinger, M.D.

2008-01-01

This study uses the new satellite-based Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission to retrieve tropospheric profiles of temperature and moisture over the data-sparse eastern Pacific Ocean. The COSMIC retrievals, which employ a global positioning system radio occultation technique combined with "first-guess" information from numerical weather prediction model analyses, are evaluated through the diagnosis of an intense atmospheric river (AR; i.e., a narrow plume of strong water vapor flux) that devastated the Pacific Northwest with flooding rains in early November 2006. A detailed analysis of this AR is presented first using conventional datasets and highlights the fact that ARs are critical contributors to West Coast extreme precipitation and flooding events. Then, the COSMIC evaluation is provided. Offshore composite COSMIC soundings north of, within, and south of this AR exhibited vertical structures that are meteorologically consistent with satellite imagery and global reanalysis fields of this case and with earlier composite dropsonde results from other landfalling ARs. Also, a curtain of 12 offshore COSMIC soundings through the AR yielded cross-sectional thermodynamic and moisture structures that were similarly consistent, including details comparable to earlier aircraft-based dropsonde analyses. The results show that the new COSMIC retrievals, which are global (currently yielding ???2000 soundings per day), provide high-resolution vertical-profile information beyond that found in the numerical model first-guess fields and can help monitor key lower-tropospheric mesoscale phenomena in data-sparse regions. Hence, COSMIC will likely support a wide array of applications, from physical process studies to data assimilation, numerical weather prediction, and climate research. ?? 2008 American Meteorological Society.

The characteristics of gas hydrates occurring in natural environment

NASA Astrophysics Data System (ADS)

Lu, H.; Moudrakovski, I.; Udachin, K.; Enright, G.; Ratcliffe, C.; Ripmeester, J.

2009-12-01

In the past few years, extensive analyses have been carried out for characterizing the natural gas hydrate samples from Cascadia, offshore Vancouver Island; Mallik, Mackenzie Delta; Mount Elbert, Alaska North Slope; Nankai Trough, offshore Japan; Japan Sea and offshore India. With the results obtained, it is possible to give a general picture of the characteristics of gas hydrates occurring in natural environment. Gas hydrate can occur in sediments of various types, from sands to clay, although it is preferentially enriched in sediments of certain types, for example coarse sands and fine volcanic ash. Most of the gas hydrates in sediments are invisible, occurring in the pores of the sediments, while some hydrates are visible, appearing as massive, nodular, planar, vein-like forms and occurring around the seafloor, in the fractures related to fault systems, or any other large spaces available in sediments. Although methane is the main component of most of the natural gas hydrates, C2 to C7 hydrocarbons have been recognized in hydrates, sometimes even in significant amounts. Shallow marine gas hydrates have been found generally to contain minor amounts of hydrogen sulfide. Gas hydrate samples with complex gas compositions have been found to have heterogeneous distributions in composition, which might reflect changes in the composition of the available gas in the surrounding environment. Depending on the gas compositions, the structure type of a natural gas hydrate can be structure I, II or H. For structure I methane hydrate, the large cages are almost fully occupied by methane molecules, while the small cages are only partly occupied. Methane hydrates occurring in different environments have been identified with almost the same crystallographic parameters.

Measurement of shallow sea floor motion with GPS on a rigid buoy: system design and synthetic analysis

NASA Astrophysics Data System (ADS)

Dixon, T. H.; Xie, S.; Malservisi, R.; Lembke, C.; Iannaccone, G.; Law, J.; Rodgers, M.; Russell, R.; Voss, N. K.

2017-12-01

A GPS-buoy system has been built and is currently undergoing test to measure precise 3D sea floor motion in the shallow (less than 200 m) continental shelf environment. Offshore deformation is undersampled in most subduction zones. In Cascadia, the shallow shelf environment constitutes roughly 20%-25% of the offshore area between the coastline and the trench. In the system being tested, the GPS receiver at the top of the buoy is connected to the sea floor through a rigid structure supported by a float. A similar design has been used by INGV (Italy) to measure vertical deformation on the sea floor near the Campi Flegrei caldera. Synthetic analysis shows that by adding a 3-axis digital compass to measure heading and tilt, along with kinematic GPS measurements, position of the anchor can be recovered to an accuracy of several centimeters or better, depending on water depth and GPS baseline length. Synthetic resolution tests show that our ability to detect shallow slow slip events on subduction plate boundaries can be greatly improved by adding offshore GPS-buoy sites.

Seismic evidence for an extensive gas-bearing layer at shallow depth, offshore from Prudhoe Bay, Alaska

USGS Publications Warehouse

Boucher, G.; Reimnitz, E.; Kempema, E.

1981-01-01

High-resolution seismic reflection data, recorded offshore from Prudhoe Bay, Alaska, were processed digitally to determine the reflectivity structure of the uppermost layers of the seafloor. A prominent reflector, found at 27 m below the mud line (water depths 7-9 m), has a negative reflection coefficient greater than 0.5. The large acoustic impedance contrast, coupled with a report of gas encountered at a corresponding depth in a nearby drillhole, shows that the reflector is the upper boundary of a zone containing gas. The gas exists in sandy gravel capped by stiff, silty clay. Analysis of unprocessed conventional high-resolution records from the region indicates that the gas-bearing layer may extend over an area of at least 50 km2 at a depth of 20-35 m below the mud line. Similar-appearing reflectors (Reimnitz, 1972), previously unexplained, occur in patches over wide regions of the shelf where offshore oil development is beginning at a rapid pace. This suggests the exercise of caution with respect to possible hazards from shallow gas pockets.

Status of the KM3NeT project

NASA Astrophysics Data System (ADS)

Margiotta, A.

2014-04-01

KM3NeT is a deep-sea research infrastructure being constructed in the Mediterranean Sea. It will be installed at three sites: KM3NeT-Fr, offshore Toulon, France, KM3NeT-It, offshore Portopalo di Capo Passero, Sicily (Italy) and KM3NeT-Gr, offshore Pylos, Peloponnese, Greece. It will host the next generation Cherenkov neutrino telescope and nodes for a deep sea multidisciplinary observatory, providing oceanographers, marine biologists, and geophysicists with real time measurements. The neutrino telescope will search for Galactic and extra-Galactic sources of neutrinos, complementing IceCube in its field of view. The detector will have a modular structure and consists of six building blocks, each including about one hundred Detection Units (DUs). Each DU will be equipped with 18 multi-PMT digital optical modules. The first phase of construction has started and shore and deep-sea infrastructures hosting the future KM3NeT detector are being prepared in France near Toulon and in Italy, near Capo Passero in Sicily. The technological solutions for KM3NeT and the expected performance of the detector are presented and discussed.

Holocene deformation offshore Ventura basin, CA, constrained by new high-resolution geophysical data

NASA Astrophysics Data System (ADS)

Perea, H.; Ucarkus, G.; Driscoll, N. W.; Kent, G. M.; Levy, Y.; Rockwell, T. K.

2017-12-01

The Transverse Ranges (Southern California, USA) accommodate the contraction resulting from a regional restraining bend in the San Andreas Fault to form a thrust-and-fold belt system. The southern boundary of this system corresponds to the E-W trending Ventura basin, which is filled by more than 5 km of Pleistocene sediment and is shortening at about 10 mm/yr as inferred from geodetic data. Although the different thrust and folds are fairly well known in the onshore areas of the basin, there is still uncertainty about their continuation in the offshore. The analysis of new high-resolution (SIO CHIRP) and existing (USGS sparker and chirp) seismic data has allowed us to characterize better the active geological structures in the offshore. In the dataset, we have identified different latest Quaternary seismostratigraphic units and horizons, with the most regionally recognized being a transgressive surface (LGTS) associated to the Last Glacial maximum and subsequent sea level rise. A series of E-W regional folds related to thrust faults have deformed the LGTS producing highs and depressions. The correlation of these structures between profiles shows that they are elongated and parallel between them and continue to the coastline. In addition, considering their trend and kinematics, we have been able to tie them with the main onshore active thrusts and folds. Above the LGTS we have identified progradational and agradational units that are related to global sea level rise, which exhibit less deformation (folding and faulting) than the lower units and horizons. However, we have recognized some specific fold growth sequences above LGTS associated with the activity of different thrust-related anticlines. Accordingly, we have identified between 3 and 5 tectonic deformation events (e.g., earthquakes) associated to thrust fault activity. These results may help us to determine the deformation history for the offshore Ventura basin and the potentiality of the thrust faults that may be tsunamigenic, and compare our observations to the onshore results.

Structural Health and Prognostics Management for Offshore Wind Turbines: Sensitivity Analysis of Rotor Fault and Blade Damage with O&M Cost Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myrent, Noah J.; Barrett, Natalie C.; Adams, Douglas E.

2014-07-01

Operations and maintenance costs for offshore wind plants are significantly higher than the current costs for land-based (onshore) wind plants. One way to reduce these costs would be to implement a structural health and prognostic management (SHPM) system as part of a condition based maintenance paradigm with smart load management and utilize a state-based cost model to assess the economics associated with use of the SHPM system. To facilitate the development of such a system a multi-scale modeling and simulation approach developed in prior work is used to identify how the underlying physics of the system are affected by themore » presence of damage and faults, and how these changes manifest themselves in the operational response of a full turbine. This methodology was used to investigate two case studies: (1) the effects of rotor imbalance due to pitch error (aerodynamic imbalance) and mass imbalance and (2) disbond of the shear web; both on a 5-MW offshore wind turbine in the present report. Sensitivity analyses were carried out for the detection strategies of rotor imbalance and shear web disbond developed in prior work by evaluating the robustness of key measurement parameters in the presence of varying wind speeds, horizontal shear, and turbulence. Detection strategies were refined for these fault mechanisms and probabilities of detection were calculated. For all three fault mechanisms, the probability of detection was 96% or higher for the optimized wind speed ranges of the laminar, 30% horizontal shear, and 60% horizontal shear wind profiles. The revised cost model provided insight into the estimated savings in operations and maintenance costs as they relate to the characteristics of the SHPM system. The integration of the health monitoring information and O&M cost versus damage/fault severity information provides the initial steps to identify processes to reduce operations and maintenance costs for an offshore wind farm while increasing turbine availability, revenue, and overall profit.« less

Europe's mild winters, due to offshore wind-farms, shipping and fishery?

NASA Astrophysics Data System (ADS)

Bernaerts, A.

2016-02-01

The winter 2014/15 was no winter in Northern Europa. In Europe the mean average temperature during the last century has risen by 0.9°C. In the last 30 years the tendency of warming per decade with about 0.41°C was significantly higher than the global mean of +0.17°C. Warming in central and northern Europe was very strong and winter temperatures rose faster than summer temperatures, and water temperatures in the North Sea and Baltic increased more than in other oceans. Can anthropogene activities between the English Channel and the Gulf of Finland be made partly responsible? Presumably yes! Stirring hot coffee will cool it down. At the end of August the sea areas have gained their maximum potential of warmth. Many ship propellers are plowing through the sea stirring the surface layer to a depth of 15 meters and more. In the North Sea and Baltic, ten thousand and more motor ships are simultaneously at sea. Several thousand offshore facilities on the bottom of the sea or anchored offshore rigs divert currents at sea and influence tides and currents as a permanent resistance against the normal flow of huge amounts of ocean water. The result is like stirring hot liquids. Warm water will come to the surface and the heat will supply the atmosphere with warmth. The air will become warmer and the winters will be milder. The correlation is not to be overseen. It is not relevant to climate research and agencies allowing offshore structures and they are neglecting such evaluations. Summary: The facts are conclusive. "Global Climate Change" cannot cause a special rise in temperatures in Northern Europe, neither in the North Sea nor the Baltic or beyond. Any use of the oceans by mankind has an influence on thermo-haline structures within the water column from a few cm to 10m and more. Noticeable warmer winters in Europe are the logical consequence.

Offshore safety case approach and formal safety assessment of ships.

PubMed

Wang, J

2002-01-01

Tragic marine and offshore accidents have caused serious consequences including loss of lives, loss of property, and damage of the environment. A proactive, risk-based "goal setting" regime is introduced to the marine and offshore industries to increase the level of safety. To maximize marine and offshore safety, risks need to be modeled and safety-based decisions need to be made in a logical and confident way. Risk modeling and decision-making tools need to be developed and applied in a practical environment. This paper describes both the offshore safety case approach and formal safety assessment of ships in detail with particular reference to the design aspects. The current practices and the latest development in safety assessment in both the marine and offshore industries are described. The relationship between the offshore safety case approach and formal ship safety assessment is described and discussed. Three examples are used to demonstrate both the offshore safety case approach and formal ship safety assessment. The study of risk criteria in marine and offshore safety assessment is carried out. The recommendations on further work required are given. This paper gives safety engineers in the marine and offshore industries an overview of the offshore safety case approach and formal ship safety assessment. The significance of moving toward a risk-based "goal setting" regime is given.

Flight Experience, Risk Taking, and Hazardous Attitudes in Glider Instructors (Experience de vol, Prise de Risque et Attitudes Dangereuses des Instructeurs de vol sur Planeur)

DTIC Science & Technology

2010-11-01

sur planeur . On a également examiné le rôle que jouent l’expérience de vol et la propension à prendre des risques dans le but d’anticiper les...données transversales, obtenues par l’observation de 144 instructeurs de vol sur planeur , en activité ou non, œuvrant dans cinq centres de vol à...137 Sommaire ..... Expérience de vol, prise de risque et attitudes dangereuses des instructeurs de vol sur planeur Ann-Renee Blais

NREL Researchers Play Integral Role in National Offshore Wind Strategy |

Science.gov Websites

News | NREL Researchers Play Integral Role in National Offshore Wind Strategy NREL Researchers Play Integral Role in National Offshore Wind Strategy December 16, 2016 A photo of three offshore wind turbines in turbulent water. Offshore wind energy in the United States is just getting started, with the

Airfoil family design for large offshore wind turbine blades

NASA Astrophysics Data System (ADS)

Méndez, B.; Munduate, X.; San Miguel, U.

2014-06-01

Wind turbine blades size has scaled-up during last years due to wind turbine platform increase especially for offshore applications. The EOLIA project 2007-2010 (Spanish Goverment funded project) was focused on the design of large offshore wind turbines for deep waters. The project was managed by ACCIONA Energia and the wind turbine technology was designed by ACCIONA Windpower. The project included the design of a wind turbine airfoil family especially conceived for large offshore wind turbine blades, in the order of 5MW machine. Large offshore wind turbines suffer high extreme loads due to their size, in addition the lack of noise restrictions allow higher tip speeds. Consequently, the airfoils presented in this work are designed for high Reynolds numbers with the main goal of reducing blade loads and mantainig power production. The new airfoil family was designed in collaboration with CENER (Spanish National Renewable Energy Centre). The airfoil family was designed using a evolutionary algorithm based optimization tool with different objectives, both aerodynamic and structural, coupled with an airfoil geometry generation tool. Force coefficients of the designed airfoil were obtained using the panel code XFOIL in which the boundary layer/inviscid flow coupling is ineracted via surface transpiration model. The desing methodology includes a novel technique to define the objective functions based on normalizing the functions using weight parameters created from data of airfoils used as reference. Four airfoils have been designed, here three of them will be presented, with relative thickness of 18%, 21%, 25%, which have been verified with the in-house CFD code, Wind Multi Block WMB, and later validated with wind tunnel experiments. Some of the objectives for the designed airfoils concern the aerodynamic behavior (high efficiency and lift, high tangential coefficient, insensitivity to rough conditions, etc.), others concern the geometry (good for structural design, compatibility for the different airfoil family members, etc.) and with the ultimate objective that the airfoils will reduce the blade loads. In this paper the whole airfoil design process and the main characteristics of the airfoil family are described. Some force coefficients for the design Reynolds number are also presented. The new designed airfoils have been studied with computational calculations (panel method code and CFD) and also in a wind tunnel experimental campaign. Some of these results will be also presented in this paper.

Lake Michigan Offshore Wind Feasibility Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boezaart, Arnold; Edmonson, James; Standridge, Charles

The purpose of this project was to conduct the first comprehensive offshore wind assessment over Lake Michigan and to advance the body of knowledge needed to support future commercial wind energy development on the Great Lakes. The project involved evaluation and selection of emerging wind measurement technology and the permitting, installation and operation of the first mid-lake wind assessment meteorological (MET) facilities in Michigan’s Great Lakes. In addition, the project provided the first opportunity to deploy and field test floating LIDAR and Laser Wind Sensor (LWS) technology, and important research related equipment key to the sitting and permitting of futuremore » offshore wind energy development in accordance with public participation guidelines established by the Michigan Great Lakes Wind Council (GLOW). The project created opportunities for public dialogue and community education about offshore wind resource management and continued the dialogue to foster Great Lake wind resource utilization consistent with the focus of the GLOW Council. The technology proved to be effective, affordable, mobile, and the methods of data measurement accurate. The public benefited from a substantial increase in knowledge of the wind resources over Lake Michigan and gained insights about the potential environmental impacts of offshore wind turbine placements in the future. The unique first ever hub height wind resource assessment using LWS technology over water and development of related research data along with the permitting, sitting, and deployment of the WindSentinel MET buoy has captured public attention and has helped to increase awareness of the potential of future offshore wind energy development on the Great Lakes. Specifically, this project supported the acquisition and operation of a WindSentinel (WS) MET wind assessment buoy, and associated research for 549 days over multiple years at three locations on Lake Michigan. Four research objectives were defined for the project including to: 1) test and validate floating LIDAR technology; 2) collect and access offshore wind data; 3) detect and measure bird and bat activity over Lake Michigan; 4) conduct an over water sound propagation study; 5) prepare and offer a college course on offshore energy, and; 6) collect other environmental, bathometric, and atmospheric data. Desk-top research was performed to select anchorage sites and to secure permits to deploy the buoy. The project also collected and analyzed data essential to wind industry investment decision-making including: deploying highly mobile floating equipment to gather offshore wind data; correlating offshore wind data with conventional on-shore MET tower data; and performing studies that can contribute to the advancement and deployment of offshore wind technologies. Related activities included: • Siting, permitting, and deploying an offshore floating MET facility; • Validating the accuracy of floating LWS using near shoreline cup anemometer MET instruments; • Assessment of laser pulse technology (LIDAR) capability to establish hub height measurement of wind conditions at multiple locations on Lake Michigan; • Utilizing an extended-season (9-10 month) strategy to collect hub height wind data and weather conditions on Lake Michigan; • Investigation of technology best suited for wireless data transmission from distant offshore structures; • Conducting field-validated sound propagation study for a hypothetical offshore wind farm from shoreline locations; • Identifying the presence or absence of bird and bat species near wind assessment facilities; • Identifying the presence or absence of benthic and pelagic species near wind assessment facilities; All proposed project activities were completed with the following major findings: • Floating Laser Wind Sensors are capable of high quality measurement and recordings of wind resources. The WindSentinel presented no significant operational or statistical limitations in recording wind data technology at a at a high confidence level as compared to traditional anemometer cup technology. • During storms, mean Turbulent Kinetic Energy (TKE) increases with height above water; • Sufficient wind resources exist over Lake Michigan to generate 7,684 kWh of power using a 850 kW rated turbine at elevations between 90 - 125 meters, a height lower than originally anticipated for optimum power generation; • Based on initial assessments, wind characteristics are not significantly different at distant (thirty-two mile) offshore locations as compared to near-shore (six mile) locations; • Significant cost savings can be achieved in generation wind energy at lower turbine heights and locating closer to shore. • Siting must be sufficiently distant from shore to minimize visual impact and to address public sentiment about offshore wind development; • Project results show that birds and bats do frequent the middle of Lake Michigan, bats more so than birds; • Based on the wind resource assessment and depths of Lake Michigan encountered during the project, future turbine placement will most likely need to incorporate floating or anchored technology; • The most appropriate siting of offshore wind energy locations will enable direct routing of transmission cables to existing generating and transmission facilities located along the Michigan shoreline; • Wind turbine noise propagation from a wind energy generating facility at a five mile offshore location will not be audible at the shoreline over normal background sound levels.« less

Damping Effects in Aerospace Structures

DTIC Science & Technology

1979-10-01

Vibration, vol.29, n02 (1973). [12] ODEN J.T. & RAMIREZ G.A.: Formulation of General Discrete Models of Thermomechanical Behaviour of Ma- terials with...Aerea Rua da Escola Politecnica 42 Lisboa Attn: AGARD National Delegate TURKEY Department of Research and Development (ARGE) Ministry of

Flood Control Structures Research Program. Annotated Bibliography on Grade Control Structures

DTIC Science & Technology

1991-09-01

evaluating the effects of geology, geomorphology, soils, land use, and climate on runoff and sediment production from major source areas; (4...Otto, and ,t:iji, Ahmed. 1987. "Theoret- ical Flow Model for Drop Structures," -’. aulic ’ngineering, Proceed- ings of the 1987 National Confere’,ce on...Facilities for Unique Flood Problems," Journal of the-Waterways and Harbors Division, ASCE, Vol 97, No. WWI, pp 185-203. The unusual climatic

Advanced Residual Strength Degradation Rate Modeling for Advanced Composite Structures. Volume II. Tasks II and III.

DTIC Science & Technology

1981-07-01

ADVANCED COMPOSITE STRUCTURES VOLUME II - TASKS Ix AND III K. N. Lauraitis Tl J. T. Ryder ?l4 D. E. Pettit ~ Lockheed-California Company S Burbank...Strength Degradation Rate Final Report Modeling for Advanced Composite Structures 1 July 1979 to 29 May 1981 Vol II - Task II and III S. PERFORMIN ONG...identify by block namber) composites , graphite/epoxy, impact damage, damaged holes, fatigue, damage propagation, residual strength, NDI 20. ABSTRACT

Summary of Research 1998, Department of Aeronautics and Astronautics

DTIC Science & Technology

1999-08-01

included which consists of conference presentations and publications, books, contributions to books, published journal papers, technical reports, and...Using Smart Materials," Journal of Smart Materials and Structures, Vol. 7, pp. 95-104, 1998. Agrawal, B. and Treanor, K., "Shape Control of a Beam Using...Piezoelectric Actuators," Journal of Smart Materials and Structures, accepted. THESES DIRECTED: Johnson, S. and Vlattas, J., "Active Vibration

30 CFR 285.641 - What must I demonstrate in my GAP?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Section 285.641 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER... and wildlife); property; the marine, coastal, or human environment; or sites, structures, or objects...

50 CFR 216.216 - Mitigation.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS Taking of Marine Mammals Incidental to Explosive Severance Activities Conducted During Offshore Structure Removal Operations on the Outer Continental Shelf in the U.S. Gulf of Mexico § 216.216 Mitigation. (a) The...

50 CFR 216.212 - Effective dates.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS Taking of Marine Mammals Incidental to Explosive Severance Activities Conducted During Offshore Structure Removal Operations on the Outer Continental Shelf in the U.S. Gulf of Mexico § 216.212 Effective dates...

Study and Test of a New Bundle-Structure Riser Stress Monitoring Sensor Based on FBG.

PubMed

Xu, Jian; Yang, Dexing; Qin, Chuan; Jiang, Yajun; Sheng, Leixiang; Jia, Xiangyun; Bai, Yang; Shen, Xiaohong; Wang, Haiyan; Deng, Xin; Xu, Liangbin; Jiang, Shiquan

2015-11-24

To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the "HYSY-981" ocean oil drilling platform. No welding and pasting were used when the sensor was installed on risers. Therefore, the installation is convenient, reliable and harmless to risers. The continuous, reasonable, time-consistent data obtained indicates that the sensor worked normally under water. In all detailed working conditions, the test results show that the sensor can do well in reflecting stresses and bending moments both in and in magnitude. The measured maximum stress is 132.7 MPa, which is below the allowable stress. In drilling and testing conditions, the average riser stress was 86.6 MPa, which is within the range of the China National Offshore Oil Corporation (CNOOC) mechanical simulation results.

Study and Test of a New Bundle-Structure Riser Stress Monitoring Sensor Based on FBG

PubMed Central

Xu, Jian; Yang, Dexing; Qin, Chuan; Jiang, Yajun; Sheng, Leixiang; Jia, Xiangyun; Bai, Yang; Shen, Xiaohong; Wang, Haiyan; Deng, Xin; Xu, Liangbin; Jiang, Shiquan

2015-01-01

To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the “HYSY-981” ocean oil drilling platform. No welding and pasting were used when the sensor was installed on risers. Therefore, the installation is convenient, reliable and harmless to risers. The continuous, reasonable, time-consistent data obtained indicates that the sensor worked normally under water. In all detailed working conditions, the test results show that the sensor can do well in reflecting stresses and bending moments both in and in magnitude. The measured maximum stress is 132.7 MPa, which is below the allowable stress. In drilling and testing conditions, the average riser stress was 86.6 MPa, which is within the range of the China National Offshore Oil Corporation (CNOOC) mechanical simulation results. PMID:26610517

Maintaining of the Eastern South Pacific Oxygen Minimum Zone (OMZ) off Chile

NASA Astrophysics Data System (ADS)

Paulmier, A.; Ruiz-Pino, D.; Garçon, V.; Farías, L.

2006-10-01

Processes regulating OMZs persistence in the oxygenated ocean remain poorly understood. Four cruises (21°-30°S) and fixed-point monitoring (36°S) between 2000 and 2002 using techniques adapted to O2 conditions as low as 1 μM allow a preliminary analysis of the entire Chilean OMZ structure. A shallow OMZ is observed in the three studied areas, although its structure differs. Off northern and central Chile, the OMZ is a permanent feature, more pronounced at the coast than further offshore. On the shelf, it forms in spring and erodes in fall. A conceptual model of two intermittent active or passive phases (intense or low biogeochemical O2 consumption) is proposed as a key mechanism for the local OMZ maintaining. The highest O2 consumptions are paradoxically favoured at the oxycline when the OMZ is less intense as offshore and on the shelf in spring and fall, suggesting a control by O2 availability of the OMZ remineralization.

Lump waves and breather waves for a (3+1)-dimensional generalized Kadomtsev-Petviashvili Benjamin-Bona-Mahony equation for an offshore structure

NASA Astrophysics Data System (ADS)

Yin, Ying; Tian, Bo; Wu, Xiao-Yu; Yin, Hui-Min; Zhang, Chen-Rong

2018-04-01

In this paper, we investigate a (3+1)-dimensional generalized Kadomtsev-Petviashvili Benjamin-Bona-Mahony equation, which describes the fluid flow in the case of an offshore structure. By virtue of the Hirota method and symbolic computation, bilinear forms, the lump-wave and breather-wave solutions are derived. Propagation characteristics and interaction of lump waves and breather waves are graphically discussed. Amplitudes and locations of the lump waves, amplitudes and periods of the breather waves all vary with the wavelengths in the three spatial directions, ratio of the wave amplitude to the depth of water, or product of the depth of water and the relative wavelength along the main direction of propagation. Of the interactions between the lump waves and solitons, there exist two different cases: (i) the energy is transferred from the lump wave to the soliton; (ii) the energy is transferred from the soliton to the lump wave.

Sea lice levels on wild Atlantic salmon, Salmo salar L., returning to the coast of Ireland.

PubMed

Jackson, D; Kane, F; O'Donohoe, P; Mc Dermott, T; Kelly, S; Drumm, A; Newell, J

2013-03-01

The sea lice population structure, prevalence and intensity of Lepeophtheirus salmonis have been studied over a period extending from 2004 to 2011. Infestation data were collected from the interceptor drift net fishery from 2004 until it was closed in 2006. From 2010, data were collected from the inshore draft net fishery. In all, 34 samples from the drift and draft net fisheries have been analysed to date. Prevalence of infestation with L. salmonis regularly approached 100% in samples of hosts recovered from the offshore drift net fishery. Abundance was variable both within and between years with a maximum mean abundance of 25.8 lice per fish recorded in 2004. The population structure of L. salmonis on hosts recovered in the inshore and estuarine draft net fisheries was different from that observed in the more offshore drift net samples. There is clear evidence of recent infestation with L. salmonis in the draft net samples. © 2013 Blackwell Publishing Ltd.

3D Crustal Structure of the North-Ligurian Margin from Refraction Tomography S. Simon (1), J.-X. Dessa (1), M.-O. Beslier (1), A. Deschamps (1), N. Béthoux (1), S. Solarino (2), E. Eva (2), F. Sage (1), G. Ferretti (3), C. Eva (3), M. Lelièvre (1), and the GROSMarin Team (1)UNS/UPMC/OCA/INSU-CNRS/IRD, Villefranche-sur-Mer, France (ssimon@geoazur.obs-vlfr.fr), (2)INGV/Dip.Te.Ris, Genova, Italia (3) Univ. Genova/Dip.Te.Ris, Genova, Italia

NASA Astrophysics Data System (ADS)

Simon, S.; Dessa, J.; Beslier, M.; Deschamps, A.; Béthoux, N.; Solarino, S.; Eva, E.; Ferretti, G.; Eva, C.; Lelievre, M.

2010-12-01

The GROSMarin experiment, held in 2008, investigates the structures of the seismically active North Ligurian rifted margin. An array of 21 Ocean Bottom Seismometers was deployed offshore a region spanning from Nice to Imperia and recorded seismic refraction shots as well as microseismicity for a duration of more than 5 months. It was extended onland by both the regional French and Italian seismic networks and 13 mobile stations that provided an even density of acquisition on- and offshore. With this programme, we aim at characterizing the main structures of this singular margin and adjacent atypical oceanic crust and thick Alpine foreland. We also seek to detect and locate microseismic events that occur regularly, mostly offshore, and that herald rare large events such as the destructive 1887 Imperia earthquake (Mw 6.5) which is the greatest seismic event in the area since at least four hundred years, and whose source and associated tectonics remain poorly understood. We present and discuss some results of our active first arrival travel time tomography that covers the margin and coastal zone and includes a total of ~185,000 picks. The transition from oceanic to continental domains is clearly evidenced as well as an intermediate zone wherein anomalously high velocities are found at the base of the crust. Velocity structures are not found to evidence significant variations along strike and locally fit some published results of 1D logs.

Historical Population Estimates For Several Fish Species At Offshore Oil and Gas Structures in the US Gulf of Mexico

NASA Astrophysics Data System (ADS)

Gitschlag, G.

2016-02-01

Population estimates were calculated for four fish species occurring at offshore oil and gas structures in water depths of 14-32 m off the Louisiana and upper Texas coasts in the US Gulf of Mexico. From 1993-1999 sampling was conducted at eight offshore platforms in conjunction with explosive salvage of the structures. To estimate fish population size prior to detonation of explosives, a fish mark-recapture study was conducted. Fish were captured on rod and reel using assorted hook sizes. Traps were occasionally used to supplement catches. Fish were tagged below the dorsal fin with plastic t-bar tags using tagging guns. Only fish that were alive and in good condition were released. Recapture sampling was conducted after explosives were detonated during salvage operations. Personnel operating from inflatable boats used dip nets to collect all dead fish that floated to the surface. Divers collected representative samples of dead fish that sank to the sea floor. Data provided estimates for red snapper (Lutjanus campechanus), Atlantic spadefish (Chaetodipterus faber), gray triggerfish (Balistes capriscus), and blue runner (Caranx crysos) at one or more of the eight platforms studied. At seven platforms, population size for red snapper was calculated at 503-1,943 with a 95% CI of 478. Abundance estimates for Atlantic spadefish at three platforms ranged from 1,432-1,782 with a 95% CI of 473. At three platforms, population size of gray triggerfish was 63-129 with a 95% CI of 82. Blue runner abundance at one platform was 558. Unlike the other three species which occur close to the platforms, blue runner range widely and recapture of this species was dependent on fish schools being in close proximity to the platform at the time explosives were detonated. Tag recapture was as high as 73% for red snapper at one structure studied.

Synthesis, characterization, X-ray crystal structure, DFT calculation and antibacterial activities of new vanadium(IV, V) complexes containing chelidamic acid and novel thiourea derivatives.

PubMed

Farzanfar, Javad; Ghasemi, Khaled; Rezvani, Ali Reza; Delarami, Hojat Samareh; Ebrahimi, Ali; Hosseinpoor, Hona; Eskandari, Amir; Rudbari, Hadi Amiri; Bruno, Giuseppe

2015-06-01

Three new thiourea ligands derived from the condensation of aroyl- and aryl-isothiocyanate derivatives with 2,6-diaminopyridine, named 1,1'-(pyridine-2,6-diyl)bis(3-(benzoyl)thiourea) (L1), 1,1'-(pyridine-2,6-diyl)bis(3-(2-chlorobenzoyl)thiourea) (L2) and 1,1'-(pyridine-2,6-diyl)bis(3-(4-chlorophenyl)thiourea) (L3), their oxido-vanadium(IV) complexes, namely [VO(L1('))(H2O)] (C1), [VO(L2('))(H2O)] (C2) and [VO(L3('))(H2O)] (C3), and also, dioxo-vanadium(V) complex containing 4-hydroxy-2,6-pyridine dicarboxylic acid (chelidamic acid, H2dipic-OH) and metformin (N,N-dimethylbiguanide, Met), named [H2Met][VO2(dipic-OH)]2·H2O (C4), were synthesized and characterized by elemental analysis, FTIR and (1)H NMR and UV-visible spectroscopies. Proposed structures for free thiourea ligands and their vanadium complexes were corroborated by applying geometry optimization and conformational analysis. Solid state structure of complex [H2Met][VO2(dipic-OH)]2·H2O (triclinic, Pī) was fully determined by single crystal X-ray diffraction analysis. In this complex, metformin is double protonated and acted as counter ion. The antibacterial properties of these compounds were investigated in vitro against standard Gram-positive and Gram-negative bacterial strains. The experiments showed that vanadium(IV) complexes had the superior antibacterial activities than novel thiourea derivatives and vanadium(V) complex against all Gram-positive and Gram-negative bacterial strains. Copyright © 2015 Elsevier Inc. All rights reserved.

The Chimborazo sector collapse and debris avalanche: Deposit characteristics as evidence of emplacement mechanisms

NASA Astrophysics Data System (ADS)

Bernard, Benjamin; van Wyk de Vries, Benjamin; Barba, Diego; Leyrit, Hervé; Robin, Claude; Alcaraz, Samantha; Samaniego, Pablo

2008-09-01

Chimborazo is a Late Pleistocene to Holocene stratovolcano located at the southwest end of the main Ecuadorian volcanic arc. It experienced a large sector collapse and debris avalanche (DA) of the initial edifice (CH-I). This left a 4 km wide scar, removing 8.0 ± 0.5 km 3 of the edifice. The debris avalanche deposit (DAD) is abundantly exposed throughout the Riobamba Basin to the Río Chambo, more than 35 km southeast of the volcano. The DAD averages a thickness of 40 m, covers about 280 km 2, and has a volume of > 11 km 3. Two main DAD facies are recognized: block and mixed facies. The block facies is derived predominantly from edifice lava and forms > 80 vol.% of the DAD, with a probable volume increase of 15-25 vol.%. The mixed facies was essentially created by mixing brecciated edifice rock with substratum and is found mainly in distal and marginal areas. The DAD has clear surface ridges and hummocks, and internal structures such as jigsaw cracks, injections, and shear-zone features are widespread. Structures such as stretched blocks along the base contact indicate high basal shear. Substratum incorporation is directly observed at the base and is inferred from the presence of substratum-derived material in the DAD body. Based on the facies and structural interpretation, we propose an emplacement model of a lava-rich avalanche strongly cataclased before and/or during failure initiation. The flow mobilises and incorporates significant substrata (10-14 vol.%) while developing a fine lubricating basal layer. The substrata-dominated mixed facies is transported to the DAD interior and top in dykes invading previously-formed fractures.

All-acrylic multigraft copolymers: Effect of side chain molecular weight and volume fraction on mechanical behavior

DOE PAGES

Goodwin, Andrew; Wang, Weiyu; Kang, Nam -Goo; ...

2015-08-21

We present in this paper the synthesis of poly(n-butyl acrylate)-g-poly(methyl methacrylate) (PnBA-g-PMMA) multigraft copolymers via a grafting-through (macromonomer) approach. The synthesis was performed using two controlled polymerization techniques. The PMMA macromonomer was obtained by high-vacuum anionic polymerization followed by the copolymerization of n-butyl acrylate and PMMA macromonomer using reversible addition–fragmentation chain transfer (RAFT) polymerization to yield the desired all-acrylic multigraft structures. The PnBA-g-PMMA multigraft structures exhibit randomly spaced branch points with various PMMA contents, ranging from 15 to 40 vol %, allowing an investigation into how physical properties vary with differences in the number of branch points and molecular weightmore » of grafted side chains. The determination of molecular weight and polydispersity indices of both the PMMA macromonomer and the graft copolymers was carried out using size exclusion chromatography with triple detection, and the structural characteristics of both the macromonomer and PnBA-g-PMMA graft materials were characterized by 1H and 13C NMR. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was employed for monitoring the macromonomer synthesis. Thermal characteristics of the materials were analyzed using differential scanning calorimetry and thermogravimetric analysis. The mechanical performance of the graft materials was characterized by rheology and dynamic mechanical analysis, revealing that samples with PMMA content of 25–40 vol % exhibit superior elastomeric properties as compared to materials containing short PMMA side chains or <25 vol % PMMA. In conclusion, atomic force microscopy showed a varying degree of microphase separation between the glassy and rubbery components that is strongly dependent on PMMA side chain molecular weight.« less

Ice Load Project Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCoy, Timothy J.; Brown, Thomas; Byrne, Alex

As interest and investment in offshore wind projects increase worldwide, some turbines will be installed in locations where ice of significant thickness forms on the water surface. This ice moves under the driving forces of wind, current, and thermal effects and may result in substantial forces on bottom-fixed support structures. The North and Baltic Seas in Europe have begun to see significant wind energy development and the Great Lakes of the United States and Canada may host wind energy development in the near future. Design of the support structures for these projects is best performed through the use of anmore » integrated tool that can calculate the cumulative effects of forces due to turbine operations, wind, waves, and floating ice. The dynamic nature of ice forces requires that these forces be included in the design simulations, rather than added as static forces to simulation results. The International Electrotechnical Commission (IEC) standard[2] for offshore wind turbine design and the International Organization for Standardization (ISO) standard[3] for offshore structures provide requirements and algorithms for the calculation of forces induced by surface ice; however, currently none of the major wind turbine dynamic simulation codes provides the ability to model ice loads. The scope of work of the project described in this report includes the development of a suite of subroutines, collectively named IceFloe, that meet the requirements of the IEC and ISO standards and couples with four of the major wind turbine dynamic simulation codes. The mechanisms by which ice forces impinge on offshore structures generally include the forces required for crushing of the ice against vertical-sided structures and the forces required to fracture the ice as it rides up on conical-sided structures. Within these two broad categories, the dynamic character of the forces with respect to time is also dependent on other factors such as the velocity and thickness of the moving ice and the response of the structure. In some cases, the dynamic effects are random and in other cases they are deterministic, such as the effect of structural resonance and coupling of the ice forces with the defection of the support structure. The initial versions of the IceFloe routines incorporate modules that address these varied force and dynamic phenomena with seven alternative algorithms that can be specified by the user. The IceFloe routines have been linked and tested with four major wind turbine aeroelastic simulation codes: FAST, a tool developed under the management of the National Renewable Energy Laboratory (NREL) and available free of charge from its web site; Bladed[4], a widely-used commercial package available from DNV GL; ADAMS[5], a general purpose multi-body simulation code used in the wind industry and available from MSC Software; and HAWC2[6], a code developed by and available for purchase from Danmarks Tekniske Universitet (DTU). Interface routines have been developed and tested with full wind turbine simulations for each of these codes and the source code and example inputs and outputs are available from the NREL website.« less

Characteristics of Offshore Hawai';i Island Seismicity and Velocity Structure, including Lo';ihi Submarine Volcano

NASA Astrophysics Data System (ADS)

Merz, D. K.; Caplan-Auerbach, J.; Thurber, C. H.

2013-12-01

The Island of Hawai';i is home to the most active volcanoes in the Hawaiian Islands. The island's isolated nature, combined with the lack of permanent offshore seismometers, creates difficulties in recording small magnitude earthquakes with accuracy. This background offshore seismicity is crucial in understanding the structure of the lithosphere around the island chain, the stresses on the lithosphere generated by the weight of the islands, and how the volcanoes interact with each other offshore. This study uses the data collected from a 9-month deployment of a temporary ocean bottom seismometer (OBS) network fully surrounding Lo';ihi volcano. This allowed us to widen the aperture of earthquake detection around the Big Island, lower the magnitude detection threshold, and better constrain the hypocentral depths of offshore seismicity that occurs between the OBS network and the Hawaii Volcano Observatory's land based network. Although this study occurred during a time of volcanic quiescence for Lo';ihi, it establishes a basis for background seismicity of the volcano. More than 480 earthquakes were located using the OBS network, incorporating data from the HVO network where possible. Here we present relocated hypocenters using the double-difference earthquake location algorithm HypoDD (Waldhauser & Ellsworth, 2000), as well as tomographic images for a 30 km square area around the summit of Lo';ihi. Illuminated by using the double-difference earthquake location algorithm HypoDD (Waldhauser & Ellsworth, 2000), offshore seismicity during this study is punctuated by events locating in the mantle fault zone 30-50km deep. These events reflect rupture on preexisting faults in the lower lithosphere caused by stresses induced by volcano loading and flexure of the Pacific Plate (Wolfe et al., 2004; Pritchard et al., 2007). Tomography was performed using the double-difference seismic tomography method TomoDD (Zhang & Thurber, 2003) and showed overall velocities to be slower than the regional velocity model (HG50; Klein, 1989) in the shallow lithosphere above 16 km depth. This is likely a result of thick deposits of volcaniclastic sediments and fractured pillow basalts that blanket the southern submarine flank of Mauna Loa, upon which Lo';ihi is currently superimposing (Morgan et al., 2003). A broad, low-velocity anomaly was observed from 20-40 km deep beneath the area of Pahala, and is indicative of the central plume conduit that supplies magma to the active volcanoes. A localized high-velocity body is observed 4-6 km deep beneath Lo';ihi's summit, extending 10 km to the North and South. Oriented approximately parallel to Lo';ihi's active rift zones, this high-velocity body is suggestive of intrusion in the upper crust, similar to Kilauea's high-velocity rift zones.

Projecting the success of plant restoration with population viability analysis

USGS Publications Warehouse

Bell, T.J.; Bowles, M.L.; McEachern, A.K.; Brigham, C.A.; Schwartz, M.W.

2003-01-01

Conserving viable populations of plant species requires that they have high probabilities of long-term persistence within natural habitats, such as a chance of extinction in 100 years of less than 5% (Menges 1991, 1998; Brown 1994; Pavlik 1994; Chap. 1, this Vol.). For endangered and threatened species that have been severely reduces in range and whose habitats have been fragmented, important species conservation strategies may include augmenting existing populations or restoring new viable populations (Bowles and Whelan 1994; Chap. 2, this Vol.). Restoration objectives may include increasing population numbers to reduce extinction probability, deterministic manipulations to develop a staged cohort structure, or more complex restoration of a desired genetic structure to allow outcrossing or increase effective population size (DeMauro 1993, 1994; Bowles et al. 1993, 1998; Pavlik 1994; Knapp and Dyer 1998; Chap. 2, this Vol.). These efforts may require translocation of propagules from existing (in situ) populations, or from ex situ botanic gardens or seed storage facilities (Falk et al. 1996; Guerrant and Pavlik 1998; Chap. 2, this Vol.). Population viability analysis (PVA) can provide a critical foundation for plant restoration, as it models demographic projections used to evaluate the probability of population persistence and links plant life history with restoration strategies. It is unknown how well artificially created populations will meet demographic modeling requirements (e.g., due to artificial cohort transitions) and few, if any, PVAs have been applied to restorations. To guide application of PVA to restored populations and to illustrate potential difficulties, we examine effects of planting different life stages, model initial population sizes needed to achieve population viability, and compare demographic characteristics between natural and restored populations. We develop and compare plant population restoration viability analysis (PRVA) case studies of two plant species listed in the USA for which federal recovery planning calls for population restoration: Cirsium pitcheri, a short-lived semelparous herb, and Asclepias meadii, a long-lived iteroparous herb.

The Cape Ghir filament system in August 2009 (NW Africa)

NASA Astrophysics Data System (ADS)

Sangrà, Pablo; Troupin, Charles; Barreiro-González, Beatriz; Desmond Barton, Eric; Orbi, Abdellatif; Arístegui, Javier

2015-06-01

In the framework of the Canaries-Iberian marine ecosystem Exchanges (CAIBEX) experiment, an interdisciplinary high-resolution survey was conducted in the NW African region of Cape Ghir (30°38'N) during August 2009. The anatomy of a major filament is investigated on scales down to the submesoscale using in situ and remotely sensed data. The filament may be viewed as a system composed of three intimately connected structures: a small, shallow, and cold filament embedded within a larger, deeper, and cool filament and an intrathermocline anticyclonic eddy (ITE). The cold filament, which stretches 110 km offshore, is a shallow feature 60 m deep and 25 km wide, identified by minimal surface temperatures and rich in chlorophyll a. This structure comprises two asymmetrical submesoscale (˜18 km) fronts with jets flowing in opposite directions. The cold filament is embedded near the equatorward boundary of a much broader region of approximately 120 km width and 150 m depth that forms the cool filament and stretches at least 200 km offshore. This cool region, partly resulting from the influence of cold filament, is limited by two asymmetrical mesoscale (˜50 km) frontal boundaries. At the ITE, located north of the cold filament, we observe evidence of downwelling as indicated by a relatively high concentration of particles extending from the surface to more than 200 m depth. We hypothesize that this ITE may act as a sink of carbon and thus the filament system may serve dual roles of offshore carbon export and carbon sink.

Offshore oil platforms and fouling communities in the southern Arabian Gulf (Abu Dhabi).

PubMed

Stachowitsch, Michael; Kikinger, Reinhard; Herler, Jürgen; Zolda, Pamela; Geutebrück, Ernst

2002-09-01

This study examined the fouling organisms on the legs of offshore oil platforms at two sites in the southern Arabian Gulf (offshore Abu Dhabi, United Arab Emirates). 100% of the metal structures was colonized by encrusting organisms. Both the number of individuals and the total biomass tended to decrease with depth. The total weight of dead shells always exceeded that of living organisms. Sessile filter feeders dominated the biomass, whereas small mobile forms had the largest number of individuals. The biomass at the deeper platform (22 m) was dominated by bivalves, barnacles and bryozoans, while polychaetes and amphipods had the greatest number of individuals. Biomass values here ranged from 1 g/0.1 m2 at 20 m to 147 g/0.1 m2 at 5 m; the corresponding individual numbers were 266 (20 m) and 11,814 indiv./0.1 m2 (5 m). The results at the shallower platform (11 m) differed in several respects: barnacles clearly dominated over bivalves, and sponges exceeded byrozoans, while total individual numbers fell due to a decline in polychaete dominance. Biomass values here ranged from 84 g/0.1 m2 at 10 m to 153 g/0.1 m2 at 0 m; the corresponding individual numbers were 695 (10 m) and 3,125 indiv./0.1 m2 (0 m). The potential role of such fouling communities on artificial structures in the Gulf is discussed.

Investigating daily fatigue scores during two-week offshore day shifts.

PubMed

Riethmeister, Vanessa; Bültmann, Ute; Gordijn, Marijke; Brouwer, Sandra; de Boer, Michiel

2018-09-01

This study examined daily scores of fatigue and circadian rhythm markers over two-week offshore day shift periods. A prospective cohort study among N = 60 offshore day-shift workers working two-week offshore shifts was conducted. Offshore day shifts lasted from 07:00 - 19:00 h. Fatigue was measured objectively with pre- and post-shift scores of the 3-minute psychomotor vigilance tasks (PVT-B) parameters (reaction times, number of lapses, errors and false starts) and subjectively with pre- and post-shift Karolinska Sleepiness Scale (KSS) ratings. Evening saliva samples were collected on offshore days 2,7 and 13 to measure circadian rhythm markers such as dim-light melatonin onset times and cortisol. Generalized and linear mixed model analyses were used to examine daily fatigue scores over time. Complete data from N = 42 offshore day shift workers was analyzed. Daily parameters of objective fatigue, PVT-B scores (reaction times, average number of lapses, errors and false starts), remained stable over the course of the two-week offshore day shifts. Daily subjective post-shift fatigue scores significantly increased over the course of the two-week offshore shifts. Each day offshore was associated with an increased post-shift subjective fatigue score of 0.06 points (95%CI: .03 - .09 p < .001). No significant statistical differences in subjective pre-shift fatigue scores were found. Neither a circadian rhythm phase shift of melatonin nor an effect on the pattern and levels of evening cortisol was found. Daily parameters of objective fatigue scores remained stable over the course of the two-week offshore day shifts. Daily subjective post-shift fatigue scores significantly increased over the course of the two-week offshore shifts. No significant changes in circadian rhythm markers were found. Increased post-shift fatigue scores, especially during the last days of an offshore shift, should be considered and managed in (offshore) fatigue risk management programs and fatigue risk prediction models. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mobile Landing Platform with Core Capability Set (MLP w/CCS): Combined Initial Operational Test and Evaluation and Live Fire Test and Evaluation Report

DTIC Science & Technology

2015-07-01

annex.   iii Self-defense testing was limited to structural test firing from each machine gun mount and an ammunition resupply drill. Robust self...provided in the classified annex. Self-   8 defense testing was limited to structural test firing from each machine gun mount and a single...Caliber Machine Gun Mount Structural Test Fire November 2014 San Diego, Offshore Ship Weapons Range Operating Independently       9 Section Three

Frontal Eddy Dynamics (FRED) experiment off North Carolina: Volume 1. Executive summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebbesmeyer, C.C.

1989-03-01

In preparation for oil and gas lease sales on the outer continental shelf offshore of North Carolina, the Minerals Management Service was requested to investigate the potential transport and impacts of oil spilled offshore. The Gulf Stream and associated eddies are an important aspect of the transport. Although the speed and location of the Gulf Stream are reasonably well known, knowledge of the meanders of the Gulf Stream is limited. How the circulatory structure and movement of associated frontal eddies and filaments affect the North Carolina coastal waters is not clear. This study investigates the interactions of these circulatory elementsmore » and follows the evolution of frontal eddies as they migrate along the North Carolina coast.« less

A methodology to model causal relationships on offshore safety assessment focusing on human and organizational factors.

PubMed

Ren, J; Jenkinson, I; Wang, J; Xu, D L; Yang, J B

2008-01-01

Focusing on people and organizations, this paper aims to contribute to offshore safety assessment by proposing a methodology to model causal relationships. The methodology is proposed in a general sense that it will be capable of accommodating modeling of multiple risk factors considered in offshore operations and will have the ability to deal with different types of data that may come from different resources. Reason's "Swiss cheese" model is used to form a generic offshore safety assessment framework, and Bayesian Network (BN) is tailored to fit into the framework to construct a causal relationship model. The proposed framework uses a five-level-structure model to address latent failures within the causal sequence of events. The five levels include Root causes level, Trigger events level, Incidents level, Accidents level, and Consequences level. To analyze and model a specified offshore installation safety, a BN model was established following the guideline of the proposed five-level framework. A range of events was specified, and the related prior and conditional probabilities regarding the BN model were assigned based on the inherent characteristics of each event. This paper shows that Reason's "Swiss cheese" model and BN can be jointly used in offshore safety assessment. On the one hand, the five-level conceptual model is enhanced by BNs that are capable of providing graphical demonstration of inter-relationships as well as calculating numerical values of occurrence likelihood for each failure event. Bayesian inference mechanism also makes it possible to monitor how a safety situation changes when information flow travel forwards and backwards within the networks. On the other hand, BN modeling relies heavily on experts' personal experiences and is therefore highly domain specific. "Swiss cheese" model is such a theoretic framework that it is based on solid behavioral theory and therefore can be used to provide industry with a roadmap for BN modeling and implications. A case study of the collision risk between a Floating Production, Storage and Offloading (FPSO) unit and authorized vessels caused by human and organizational factors (HOFs) during operations is used to illustrate an industrial application of the proposed methodology.

50 CFR Figure 1 to Subpart I of... - Existing California Area Closures (hatched areas extend to 3 miles offshore; cross-hatched areas...

Code of Federal Regulations, 2011 CFR

2011-10-01

... (hatched areas extend to 3 miles offshore; cross-hatched areas extend beyond 3 miles offshore) and Optional.... I, Fig. 1 Figure 1 to Subpart I of Part 660—Existing California Area Closures (hatched areas extend to 3 miles offshore; cross-hatched areas extend beyond 3 miles offshore) and Optional Catalina...

50 CFR Figure 1 to Subpart I of... - Existing California Area Closures (hatched areas extend to 3 miles offshore; cross-hatched areas...

Code of Federal Regulations, 2013 CFR

2013-10-01

... (hatched areas extend to 3 miles offshore; cross-hatched areas extend beyond 3 miles offshore) and Optional.... I, Fig. 1 Figure 1 to Subpart I of Part 660—Existing California Area Closures (hatched areas extend to 3 miles offshore; cross-hatched areas extend beyond 3 miles offshore) and Optional Catalina...

50 CFR Figure 1 to Subpart I of... - Existing California Area Closures (hatched areas extend to 3 miles offshore; cross-hatched areas...

Code of Federal Regulations, 2012 CFR

2012-10-01

... (hatched areas extend to 3 miles offshore; cross-hatched areas extend beyond 3 miles offshore) and Optional.... I, Fig. 1 Figure 1 to Subpart I of Part 660—Existing California Area Closures (hatched areas extend to 3 miles offshore; cross-hatched areas extend beyond 3 miles offshore) and Optional Catalina...

50 CFR Figure 1 to Subpart I of... - Existing California Area Closures (hatched areas extend to 3 miles offshore; cross-hatched areas...

Code of Federal Regulations, 2014 CFR

2014-10-01

... (hatched areas extend to 3 miles offshore; cross-hatched areas extend beyond 3 miles offshore) and Optional.... I, Fig. 1 Figure 1 to Subpart I of Part 660—Existing California Area Closures (hatched areas extend to 3 miles offshore; cross-hatched areas extend beyond 3 miles offshore) and Optional Catalina...

Minicourses in Astrophysics, Modular Approach, Vol. II.

ERIC Educational Resources Information Center

Illinois Univ., Chicago.

This is the second of a two-volume minicourse in astrophysics. It contains chapters on the following topics: stellar nuclear energy sources and nucleosynthesis; stellar evolution; stellar structure and its determination; and pulsars. Each chapter gives much technical discussion, mathematical treatment, diagrams, and examples. References are…

Slick Nanoparticles and Other Gleanings from Nature

NASA Astrophysics Data System (ADS)

Heinhorst, Sabine; Cannon, Gordon C.

1997-09-01

The total synthesis of a new class of compounds that promise to be cancer chemotherapeutic agents at least as effective as taxol was presented in the May 15 issue (Vol. 387, pp 238-239) as a "News and Views" article. Although structurally unrelated, epothilones, like taxol, target the microtubules of the cytoskeleton and inhibit cancer cell growth by polymerizing these subcellular structures. Future research will have to determine which derivatives of natural epothilones are effective and which functional groups hold the key to the compounds' biological activity. An article by Deshpande and Danishefsky (May 8 issue of Vol. 387, pp 164-166) details the successful chemical synthesis of an oligosaccharide that is frequently found on the surface of colon adenocarcinomas. While the small quantities of this cancer antigen that can be purified from natural sources preclude its usefulness as an immunological tool, the synthetic compound and an analog that can be linked to a carrier molecule for biological delivery have potential as vaccines for several human cancers.

Impact of Parameter Variation in Fabrication of Nanostructure by Atomic Force Microscopy Nanolithography

PubMed Central

Dehzangi, Arash; Larki, Farhad; Hutagalung, Sabar D.; Goodarz Naseri, Mahmood; Majlis, Burhanuddin Y.; Navasery, Manizheh; Hamid, Norihan Abdul; Noor, Mimiwaty Mohd

2013-01-01

In this letter, we investigate the fabrication of Silicon nanostructure patterned on lightly doped (1015 cm−3) p-type silicon-on-insulator by atomic force microscope nanolithography technique. The local anodic oxidation followed by two wet etching steps, potassium hydroxide etching for silicon removal and hydrofluoric etching for oxide removal, are implemented to reach the structures. The impact of contributing parameters in oxidation such as tip materials, applying voltage on the tip, relative humidity and exposure time are studied. The effect of the etchant concentration (10% to 30% wt) of potassium hydroxide and its mixture with isopropyl alcohol (10%vol. IPA ) at different temperatures on silicon surface are expressed. For different KOH concentrations, the effect of etching with the IPA admixture and the effect of the immersing time in the etching process on the structure are investigated. The etching processes are accurately optimized by 30%wt. KOH +10%vol. IPA in appropriate time, temperature, and humidity. PMID:23776479

Enhanced Structural Interpretation Using Multitrace Seismic Attribute For Oligo-Miocene Target at Madura Strait Offshore

NASA Astrophysics Data System (ADS)

Pratama Wahyu Hidayat, Putra; Hary Murti, Antonius; Sudarmaji; Shirly, Agung; Tiofan, Bani; Damayanti, Shinta

2018-03-01

Geometry is an important parameter for the field of hydrocarbon exploration and exploitation, it has significant effect to the amount of resources or reserves, rock spreading, and risk analysis. The existence of geological structure or fault becomes one factor affecting geometry. This study is conducted as an effort to enhance seismic image quality in faults dominated area namely offshore Madura Strait. For the past 10 years, Oligo-Miocene carbonate rock has been slightly explored on Madura Strait area, the main reason because migration and trap geometry still became risks to be concern. This study tries to determine the boundary of each fault zone as subsurface image generated by converting seismic data into variance attribute. Variance attribute is a multitrace seismic attribute as the derivative result from amplitude seismic data. The result of this study shows variance section of Madura Strait area having zero (0) value for seismic continuity and one (1) value for discontinuity of seismic data. Variance section shows the boundary of RMKS fault zone with Kendeng zone distinctly. Geological structure and subsurface geometry for Oligo-Miocene carbonate rock could be identified perfectly using this method. Generally structure interpretation to identify the boundary of fault zones could be good determined by variance attribute.

High-resolution multi-channel seismic images of the Queen Charlotte Fault system offshore southeastern Alaska

NASA Astrophysics Data System (ADS)

Miller, N. C.; Brothers, D. S.; Kluesner, J.; Balster-Gee, A.; Ten Brink, U. S.; Andrews, B. D.; Haeussler, P. J.; Watt, J. T.; Dartnell, P.; East, A. E.

2016-12-01

We present high-resolution multi-channel seismic (MCS) images of fault structure and sedimentary stratigraphy along the southeastern Alaska margin, where the northern Queen Charlotte Fault (QCF) cuts the shelf-edge and slope. The QCF is a dominantly strike slip system that forms the boundary between the Pacific (PA) and North American (NA) plates offshore western Canada and southeastern Alaska. The data were collected using a 64 channel, 200 m digital streamer and a 0.75-3 kJ sparker source aboard the R/V Norseman in August 2016. The survey was designed to cross a seafloor fault trace recently imaged by multibeam sonar (see adjacent poster by Brothers et al.) and to extend the subsurface information landward and seaward from the fault. Analysis of these MCS and multibeam data focus on addressing key questions that have significant implications for the kinematic and geodynamic history of the fault, including: Is the imaged surface fault in multibeam sonar the only recently-active fault trace? What is the shallow fault zone width and structure, is the internal structure of the recently-discovered pull-apart basin a dynamically developing structure? How does sediment thickness vary along the margin and how does this variation affect the fault expression? Can previous glacial sequences be identified in the stratigraphy?

Health monitoring of offshore structures using wireless sensor network: experimental investigations

NASA Astrophysics Data System (ADS)

Chandrasekaran, Srinivasan; Chitambaram, Thailammai

2016-04-01

This paper presents a detailed methodology of deploying wireless sensor network in offshore structures for structural health monitoring (SHM). Traditional SHM is carried out by visual inspections and wired systems, which are complicated and requires larger installation space to deploy while decommissioning is a tedious process. Wireless sensor networks can enhance the art of health monitoring with deployment of scalable and dense sensor network, which consumes lesser space and lower power consumption. Proposed methodology is mainly focused to determine the status of serviceability of large floating platforms under environmental loads using wireless sensors. Data acquired by the servers will analyze the data for their exceedance with respect to the threshold values. On failure, SHM architecture will trigger an alarm or an early warning in the form of alert messages to alert the engineer-in-charge on board; emergency response plans can then be subsequently activated, which shall minimize the risk involved apart from mitigating economic losses occurring from the accidents. In the present study, wired and wireless sensors are installed in the experimental model and the structural response, acquired is compared. The wireless system comprises of Raspberry pi board, which is programmed to transmit the acquired data to the server using Wi-Fi adapter. Data is then hosted in the webpage for further post-processing, as desired.

Characterization of the influence of 1-butyl-3-methylimidazolium chloride on the structure and thermal stability of green fluorescent protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heller, William T; O'Neill, Hugh Michael; Zhang, Qiu

2010-01-01

Ionic liquids (ILs) are finding a vast array of applications as novel solvents for a wide variety of processes that include enzymatic chemistry, particularly as more biocompatible ILs are designed and discovered. While it is assumed that a native or near-native structure is required for enzymatic activity, there is some evidence that ILs alter protein structure and oligomerization states in a manner than can negatively impact function. The IL 1-butyl-3-methylimidazolium chloride, [bmim]Cl, is a well-studied, water-miscible member of the popular 1-alkyl-3-methylimidazolium IL family. To improve our understanding of the impact of water-miscible ILs on proteins, we have characterized the structuremore » and oligomerization state of green fluorescent protein (GFP) in aqueous solutions containing 25 and 50 vol % [bmim]Cl using a combination of optical spectroscopy and small-angle neutron scattering (SANS). Measurements were also performed as a function of temperature to provide insight into the effect of the IL on the thermal stability of GFP. While GFP exists as a dimer in water, the presence of 25 vol % [bmim]Cl causes GFP to transition to a monomeric state. The SANS data indicate that GFP is a great deal less compact in 50 vol % [bmim]Cl than in neat water, indicative of unfolding from the native structure. The oligomerization state of the protein in IL-containing aqueous solution changes from a dimer to a monomer in response to the IL, but does not change as a function of temperature in the IL-containing solution. The SANS and spectroscopic results also demonstrate that the addition of [bmim]Cl to the solution decreases the thermal stability of GFP, allowing the protein to unfold at lower temperatures than in aqueous solution.« less

30 CFR 585.610 - What must I include in my SAP?

Code of Federal Regulations, 2013 CFR

2013-07-01

... offshore and onshore. (6) General structural and project design, fabrication, and installation Information... requested by BOEM. (b) You must provide the results of geophysical and geological surveys, hazards surveys, archaeological surveys (if required), and baseline collection studies (e.g., biological) with the supporting data...

30 CFR 585.610 - What must I include in my SAP?

Code of Federal Regulations, 2014 CFR

2014-07-01

... offshore and onshore. (6) General structural and project design, fabrication, and installation Information... requested by BOEM. (b) You must provide the results of geophysical and geological surveys, hazards surveys, archaeological surveys (if required), and baseline collection studies (e.g., biological) with the supporting data...

30 CFR 585.610 - What must I include in my SAP?

Code of Federal Regulations, 2012 CFR

2012-07-01

... offshore and onshore. (6) General structural and project design, fabrication, and installation Information... requested by BOEM. (b) You must provide the results of geophysical and geological surveys, hazards surveys, archaeological surveys (if required), and baseline collection studies (e.g., biological) with the supporting data...

30 CFR 585.641 - What must I demonstrate in my GAP?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Section 585.641 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Plans and... marine, coastal, or human environment; or sites, structures, or objects of historical or archaeological...

30 CFR 585.641 - What must I demonstrate in my GAP?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Section 585.641 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Plans and... marine, coastal, or human environment; or sites, structures, or objects of historical or archaeological...

30 CFR 585.641 - What must I demonstrate in my GAP?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Section 585.641 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Plans and... marine, coastal, or human environment; or sites, structures, or objects of historical or archaeological...

30 CFR 285.906 - What must my decommissioning application include?

Code of Federal Regulations, 2011 CFR

2011-07-01

... include? 285.906 Section 285.906 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY ALTERNATE USES OF EXISTING FACILITIES ON THE... or marine mammals at the structure site. (i) Mitigation measures you will use to protect...

77 FR 5002 - Wind and Water Power Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-01

... with offshore wind turbine support structures, will not be accepted. DOE may fund specific technical... DEPARTMENT OF ENERGY Office of Energy Efficiency and Renewable Energy Wind and Water Power Program...-solicitation public meeting, request for comment. SUMMARY: The Wind and Water Power Program (WWPP) within the U...

50 CFR 216.213 - Permissible methods of taking.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS Taking of Marine Mammals Incidental to Explosive Severance Activities Conducted During Offshore Structure Removal Operations on the Outer Continental Shelf in the U.S. Gulf of Mexico § 216.213 Permissible...

50 CFR 216.218 - Letters of Authorization.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS Taking of Marine Mammals Incidental to Explosive Severance Activities Conducted During Offshore Structure Removal Operations on the Outer Continental Shelf in the U.S. Gulf of Mexico § 216.218 Letters of...

78 FR 35363 - Marine Mammals; Incidental Take During Specified Activities

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-12

... design criteria for any planned structure. Methodology for geotechnical surveys may vary between those..., depending on the type of activity. Offshore activities, such as exploration drilling, seismic surveys, and shallow hazards surveys, are expected to occur only during the open- water season (July-November). Onshore...

A heuristic simulation model of Lake Ontario circulation and mass balance transport

USGS Publications Warehouse

McKenna, J.E.; Chalupnicki, M.A.

2011-01-01

The redistribution of suspended organisms and materials by large-scale currents is part of natural ecological processes in large aquatic systems but can contribute to ecosystem disruption when exotic elements are introduced into the system. Toxic compounds and planktonic organisms spend various lengths of time in suspension before settling to the bottom or otherwise being removed. We constructed a simple physical simulation model, including the influence of major tributaries, to qualitatively examine circulation patterns in Lake Ontario. We used a simple mass balance approach to estimate the relative water input to and export from each of 10 depth regime-specific compartments (nearshore vs. offshore) comprising Lake Ontario. Despite its simplicity, our model produced circulation patterns similar to those reported by more complex studies in the literature. A three-gyre pattern, with the classic large counterclockwise central lake circulation, and a simpler two-gyre system were both observed. These qualitative simulations indicate little offshore transport along the south shore, except near the mouths of the Niagara River and Oswego River. Complex flow structure was evident, particularly near the Niagara River mouth and in offshore waters of the eastern basin. Average Lake Ontario residence time is 8 years, but the fastest model pathway indicated potential transport of plankton through the lake in as little as 60 days. This simulation illustrates potential invasion pathways and provides rough estimates of planktonic larval dispersal or chemical transport among nearshore and offshore areas of Lake Ontario. ?? 2011 Taylor & Francis.

[Reliability and validity of the Occupational Stress Scale for Chinese offshore oil platform workers].

PubMed

Chen, Wei-qing; Huang, Zi-hui; Yu, De-xin; Lin, Yan-zu; Ling, Zhi-ming; Tang, Ji-song

2003-02-01

To evaluate the validity and reliability of the Occupational Stress Scale (OSS) for Chinese offshore oil platform workers. A 51-item self-administered questionnaire developed in the light of Cooper's questionnaire and company's special situation was used to investigate 561 subjects. 51 occupational stress items relating to offshore oil production were subjected to factor analysis, and nine latent factors were identified, which explained 62.5% of the total variance. According to the contents described by the items included in each factor, they were respectively defined as: "the interface between job and family/social life (factor 1)", "career and achievement (factor 2)", "safety (factor 3)", "management problem and relationship with others at work (factor 4)", "physical factors of workplace (factor 5)", "platform living environment (factor 6)", "role in management (factor 7)", "ergonomics (factor 8)" and "organization structure (factor 9)". Significant difference in the score of five factors was observed among 12 different job categories by analysis of variance. After adjusting for potential confounding factors (age, educational level), hierarchical multiple regression analysis indicated that the score of the OSS was significantly and positively correlated with the poor mental health of the workers (P < 0.01). The consistent test between OSS and each factor showed that Cronbach's alpha were 0.72 - 0.91. The OSS is a valid and reliable tool for measuring occupational stress, and can be used to explore occupational stress and its influence on health and safety problems in offshore oil workers.

3D Velocity Structure in Southern Haiti from Local Earthquake Tomography

NASA Astrophysics Data System (ADS)

Douilly, R.; Ellsworth, W. L.; Kissling, E. H.; Freed, A. M.; Deschamps, A.; de Lepinay, B. M.

2016-12-01

We investigate 3D local earthquake tomography for high-quality travel time arrivals from aftershocks following the 2010 M7.0 Haiti earthquake on the Léogâne fault. The data were recorded by 35 stations, including 19 ocean bottom seismometers, from which we selected 595 events to simultaneously invert for hypocenter location and 3D Vp and Vs velocity structures in southern Haiti. We performed several resolution tests and concluded that clear features can be recovered to a depth of 15 km. At 5km depth we distinguish a broad low velocity zone in the Vp and Vs structure offshore near Gonave Island, which correlate with layers of marine sediments. Results show a pronounced low velocity zone in the upper 5 km across the city of Léogâne, which is consistent with the sedimentary basin location from geologic map. At 10 km depth, we detect a low velocity anomaly offshore near the Trois Baies fault and a NW-SE directed low velocity zone onshore across Petit-Goâve and Jacmel, which is consistent with a suspected fault from a previous study and that we refer to it in our study as the Petit-Goâve-Jacmel fault (PGJF). These observations suggest that low velocity structures delineate fault structures and the sedimentary basins across the southern peninsula, which is extremely useful for seismic hazard assessment in Haiti.

77 FR 17491 - National Offshore Safety Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-26

... from the Mobile Offshore Drilling Unit Guidance Policy, Notice of Availability, request for comments... DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket No. USCG-2012-0091] National Offshore Safety... Management; Notice of Federal Advisory Committee Meetings. SUMMARY: The National Offshore Safety Advisory...

JPRS Report, Science & Technology, USSR: Life Sciences

DTIC Science & Technology

1989-03-07

BIOORGANICHESKAYA KHIMIYA, Vol 14 No 4, Apr 88] 19 Intrinsic Fluorescence Studies on Effects of pH on Structure of Mistletoe Lectin [T. L. Bushuyeva, A. G...Figures 2; references 15: 3 Russian, 12 Western. UDC 576.8.097.29:547.962.3 Intrinsic Fluorescence Studies on Effects of pH on Structure of Mistletoe ...characteristics of the mistletoe lectin I (MLI), a molecule consisting of A (29 kD) and a B (34 kD) subunit, were used in assessing the structural

Review of potential impacts to sea turtles from underwater explosive removal of offshore structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viada, Stephen T.; Hammer, Richard M.; Racca, Roberto

2008-05-15

The purpose of this study was to collect and synthesize existing information relevant to the explosive removal of offshore structures (EROS) in aquatic environments. Data sources were organized and summarized by topic - explosive removal methods, physics of underwater explosions, sea turtle resources, documented impacts to sea turtles, and mitigation of effects. Information was gathered via electronic database searches and literature source review. Bulk explosive charges are the most commonly used technique in EROS. While the physical principles of underwater detonations and the propagation of pressure and acoustic waves are well understood, there are significant gaps in the application ofmore » this knowledge. Impacts to sea turtles from explosive removal operations may range from non-injurious effects (e.g. acoustic annoyance; mild tactile detection or physical discomfort) to varying levels of injury (i.e. non-lethal and lethal injuries). Very little information exists regarding the impacts of underwater explosions on sea turtles. Effects of explosions on turtles often must be inferred from documented effects to other vertebrates with lungs or other gas-containing organs, such as mammals and most fishes. However, a cautious approach should be used when determining impacts to sea turtles based on extrapolations from other vertebrates. The discovery of beached sea turtles and bottlenose dolphins following an explosive platform removal event in 1986 prompted the initiation of formal consultation between the U.S. Department of the Interior, Minerals Management Service (MMS) and the National Marine Fisheries Service (NMFS), authorized through the Endangered Species Act Section 7, to determine a mechanism to minimize potential impacts to listed species. The initial consultation resulted in a requirement for oil and gas companies to obtain a permit (through separate consultations on a case-by-case basis) prior to using explosives in Federal waters. Because many offshore structure removal operations are similar, a 'generic' Incidental Take Statement was established by the NMFS that describes requirements to protect sea turtles when an operator's individual charge weights did not exceed 50 lb (23 kg). Requirements associated with the Incidental Take Permit were revised in 2003 and 2006 to accommodate advances in explosive charge technologies, removals of structures in deeper waters, and adequate protection of deep water marine mammal species in Gulf of Mexico waters. Generally, these requirements include pre- and post-detonation visual monitoring using standard surface and aerial survey methods for sea turtles and marine mammals, and, in some scenarios, passive acoustic survey methods for marine mammals within a specified radius from an offshore structure. The survey program has been successful in mitigating impacts to sea turtles associated with EROS. However, even with these protective measures in place, there have been observations of sea turtles affected by explosive platform removals.« less

Optimization of monitoring and inspections in the life-cycle of wind turbines

NASA Astrophysics Data System (ADS)

Hanish Nithin, Anu; Omenzetter, Piotr

2016-04-01

The past decade has witnessed a surge in the offshore wind farm developments across the world. Although this form of cleaner and greener energy is beneficial and eco-friendly, the production of wind energy entails high life-cycle costs. The costs associated with inspections, monitoring and repairs of wind turbines are primary contributors to the high costs of electricity produced in this way and are disadvantageous in today's competitive economic environment. There is limited research being done in the probabilistic optimization of life-cycle costs of offshore wind turbines structures and their components. This paper proposes a framework for assessing the life cycle cost of wind turbine structures subject to damage and deterioration. The objective of the paper is to develop a mathematical probabilistic cost assessment framework which considers deterioration, inspection, monitoring, repair and maintenance models and their uncertainties. The uncertainties are etched in the accuracy and precision of the monitoring and inspection methods and can be considered through the probability of damage detection of each method. Schedules for inspection, monitoring and repair actions are demonstrated using a decision tree. Examples of a generalised deterioration process integrated with the cost analysis using a decision tree are shown for a wind turbine foundation structure.

The Shock and Vibration Bulletin. Part 2. Opening Session, Panel Session, Shock Testing and Analysis, Fluid-structure Topics

DTIC Science & Technology

1976-08-01

would like to 20 g’s rms and this would be instead of the to mention is that the IES under the leadership present single frequency non resonant 2.2 g am...Vol. 11, 1970. 19. Thomson, W. T., Vibration Theory 7. Cremer , L. and Heckl, M. and and Applications, Prentice-Hall, Ungar, E. E., Structure-Borne

The effect of alumina particles on the microstructural and mechanical properties of copper foams fabricated by space-holder method

NASA Astrophysics Data System (ADS)

Salvo, C.; Aguilar, C.; Lascano, S.; Pérez, L.; López, M.; Mangalaraja, R. V.

2018-05-01

The copper foam is an interesting field of research because of its several advantages as an engineering material. Powder metallurgy presents an alternative route to obtain a porous structure with high strength to weight ratio and functional properties. The viability of processing copper foam separately with two different space-holders such as ammonium hydrogen carbonate (NH4HCO3) and sodium chloride (NaCl) of 50 vol% was studied. The green compacts obtained under 200 MPa were sintered at different cycles for the complete removal of space-holder. The sintered foams were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and uniaxial testing machine (UTM) to study their structural features and compressive strength, respectively. The results showed that NaCl particles were the best alternative to obtain a porous structure, hence two different sizes (1 and 0.01 μm) of alumina (Al2O3) particles with 2, 4 and 6 vol% were used to fabricate copper foams. As a result, a bimodal structure consisting of macro and micropores with a highly interconnected porosity was achieved. In addition, the smaller size alumina particles promoted a higher density of pores, however, the compressive strength was reduced for the higher volume fraction of alumina particles.

Layered nanocomposites inspired by the structure and mechanical properties of nacre.

PubMed

Wang, Jianfeng; Cheng, Qunfeng; Tang, Zhiyong

2012-02-07

Nacre (mother-of-pearl), made of inorganic and organic constituents (95 vol% aragonite calcium carbonate (CaCO(3)) platelets and 5 vol% elastic biopolymers), possesses a unique combination of remarkable strength and toughness, which is compatible for conventional high performance materials. The excellent mechanical properties are related to its hierarchical structure and precisely designed organic-inorganic interface. The rational design of aragonite platelet strength, aspect ratio of aragonite platelets, and interface strength ensures that the strength of nacre is maximized under platelet pull-out failure mode. At the same time, the synergy of strain hardening mechanisms acting over multiple scales results in platelets sliding on one another, and thus maximizes the energy dissipation of viscoplastic biopolymers. The excellent integrated mechanical properties with hierarchical structure have inspired chemists and materials scientists to develop biomimetic strategies for artificial nacre materials. This critical review presents a broad overview of the state-of-the-art work on the preparation of layered organic-inorganic nanocomposites inspired by nacre, in particular, the advantages and disadvantages of various biomimetic strategies. Discussion is focused on the effect of the layered structure, interface, and component loading on strength and toughness of nacre-mimic layered nanocomposites (148 references). This journal is © The Royal Society of Chemistry 2012

78 FR 18614 - National Offshore Safety Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-27

... Continental Shelf (OCS); (b) Electrical Equipment in Hazardous Areas on Foreign Flag Mobile Offshore Drilling... DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket No. USCG-2013-0182] National Offshore Safety... Advisory Committee Meetings. SUMMARY: The National Offshore Safety Advisory Committee (NOSAC) will meet on...

76 FR 11503 - National Offshore Safety Advisory Committee; Vacancies

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-02

... person representing enterprises specializing in offshore drilling. To be eligible, applicants for all... DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket No. USCG-2011-0040] National Offshore Safety... Coast Guard seeks applications for membership on the National Offshore Safety Advisory Committee. This...

76 FR 39410 - National Offshore Safety Advisory Committee; Vacancies

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-06

... energy industry; (d) One member representing enterprises specializing in offshore drilling; and, (e) One... DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket No. USCG-2011-0539] National Offshore Safety... Coast Guard seeks applications for membership on the National Offshore Safety Advisory Committee. This...

Structural inheritance and coastal geomorphology in SW Brittany, France: An onshore/offshore integrated approach

NASA Astrophysics Data System (ADS)

Raimbault, Céline; Duperret, Anne; Le Gall, Bernard; Authemayou, Christine

2018-04-01

The Variscan crystalline basement exposed along the SW Brittany coast recorded extensive long-term planation processes during Mesozoic times. Detailed onshore-offshore mapping (600 km2) in the Penmarc'h-Concarneau granitic coastal area reveals a km-scale, deeply fractured submarine rocky shelf. High-resolution offshore imagery (bathymetry and seismic reflection dataset), combined to structural field investigations, on these surfaces allow us to identify a preserved network of both ductile and brittle structures. The inherited fault pattern is dominated by the N160°E-trending and long-lived Concarneau-Toulven fault zone (CTFS) that separates two distinct morphostructural blocks, and strongly influences the seaward limit of the Concarneau submarine rocky shelf, as well as the linear coastline of the Concarneau embayment. The structural imprint of the CTFS decreases progressively westwards with respect to a composite network of large-scale N50°E- and N140°E-oriented faults bounding the seaward edge of the Penmarc'h rocky shelf. The latter in turn splits into three large-scale blocks along N50°E- (La Torche Fault - LTF), N140°E- (Saint Guénolé Fault - SGF) and N160°E-trending normal faults. The morphostructural evolutionary model applied here to the Penmarc'h-Concarneau granitic coastal area resulted from the combined effects of structural Variscan inheritance and post-Variscan tectonics. Paleo-stress analysis of striated fault planes indicates three main Cenozoic tectonic events, inferred to have operated from Eocene to post-Oligocene times. The 3D-architecture of the Concarneau embayment, as a rocky shelf partially sealed with quaternary sediments, chiefly resulted from the reactivation of the CTFS during Eocene and Oligocene times. Further west, the surface of the Penmarc'h rocky shelf was tilted southeastward by the brittle reactivation of the LTF, and dissected by a horst-graben network post-Oligocene in age. The present-day morphology of the Penmarc'h and Concarneau domains depends on distinct driving processes: the Concarneau N160°E coastline is clearly controlled by tectonic processes via the CTFS, while the Penmarc'h headland land-sea contact appears to have been shaped by post-Cenozoic eustatism.

A quantitative method for estimating dermal benzene absorption from benzene-containing hydrocarbon liquids.

PubMed

Petty, Stephen E; Nicas, Mark; Boiarski, Anthony A

2011-01-01

This study examines a method for estimating the dermal absorption of benzene contained in hydrocarbon liquids that contact the skin. This method applies to crude oil, gasoline, organic solvents, penetrants, and oils. The flux of benzene through occluded skin as a function of the percent vol/vol benzene in the liquid is derived by fitting a curve to experimental data; the function is supralinear at benzene concentrations < or = 5% vol/vol. When a liquid other than pure benzene is on nonoccluded skin, benzene may preferentially evaporate from the liquid, which thereby decreases the benzene flux. We present a time-averaging method here for estimating the reduced dermal flux during evaporation. Example calculations are presented for benzene at 2% vol/vol in gasoline, and for benzene at 0.1% vol/vol in a less volatile liquid. We also discuss other factors affecting dermal absorption.

The Structure of Analogical Models in Science.

DTIC Science & Technology

1980-07-01

standard 69I edition of the complete psychological words of Sigmund Freud , Vol. XVII. London, The Hogarth Press Ltd. and the Isltitute of Psycho-Analysis...Intelligence. Cambridge, Ma.: MIT, 1977, 299-304. Freud , S. On transformations of instinct as exemplified in anal eroticism. In J. Strachey (Ed.), The

Acquisition Review Quarterly (ARQ) Vol. 4, No. 4.

DTIC Science & Technology

1997-01-01

served. Truly, as the African proverb has it, when elephants fight, the grass suffers. In a sinister twist, there is now a big push to get...institutionalizing a formal structure for reporting issues, problems, required actions, and successes. The re- ports were consolidated into a keystone

Blood Program in World War II. Medical Department, United States Army

DTIC Science & Technology

1964-01-01

Branch Lieutenant Colonel JEROME RUDBERG, MSC, USA, Chief, Information Activities Branch RODERICK M. ENGERT, Chief, General Reference and Research... Activities of Medical Consultants Vol. II. Infectious Diseases Preventive Medicine in World War II: Vol. II. Environmental Hygiene Vol. III. Personal...Other Than Malaria Vr VIII Surgery in World War II: Activities of Surgical Consultants, vol. I Activities of Surgical Consultants, vol. II General

47 CFR 22.1037 - Application requirements for offshore stations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... telephone number of the applicant; (2) The location and geographical coordinates of the proposed station; (3... 47 Telecommunication 2 2013-10-01 2013-10-01 false Application requirements for offshore stations... for offshore stations. Applications for new Offshore Radiotelephone Service stations must contain an...

47 CFR 22.1037 - Application requirements for offshore stations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... telephone number of the applicant; (2) The location and geographical coordinates of the proposed station; (3... 47 Telecommunication 2 2011-10-01 2011-10-01 false Application requirements for offshore stations... for offshore stations. Applications for new Offshore Radiotelephone Service stations must contain an...

47 CFR 22.1037 - Application requirements for offshore stations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... telephone number of the applicant; (2) The location and geographical coordinates of the proposed station; (3... 47 Telecommunication 2 2014-10-01 2014-10-01 false Application requirements for offshore stations... for offshore stations. Applications for new Offshore Radiotelephone Service stations must contain an...

47 CFR 22.1037 - Application requirements for offshore stations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... telephone number of the applicant; (2) The location and geographical coordinates of the proposed station; (3... 47 Telecommunication 2 2012-10-01 2012-10-01 false Application requirements for offshore stations... for offshore stations. Applications for new Offshore Radiotelephone Service stations must contain an...

50 CFR 216.211 - Specified activity and specified geographical region.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Specified activity and specified... Activities Conducted During Offshore Structure Removal Operations on the Outer Continental Shelf in the U.S. Gulf of Mexico § 216.211 Specified activity and specified geographical region. (a) Regulations in this...

50 CFR 216.211 - Specified activity and specified geographical region.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Specified activity and specified... Activities Conducted During Offshore Structure Removal Operations on the Outer Continental Shelf in the U.S. Gulf of Mexico § 216.211 Specified activity and specified geographical region. (a) Regulations in this...

30 CFR 585.906 - What must my decommissioning application include?

Code of Federal Regulations, 2014 CFR

2014-07-01

... include? 585.906 Section 585.906 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF... conducted in the vicinity of the structure and recent observations of turtles or marine mammals at the...

30 CFR 585.906 - What must my decommissioning application include?

Code of Federal Regulations, 2013 CFR

2013-07-01

... include? 585.906 Section 585.906 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF... conducted in the vicinity of the structure and recent observations of turtles or marine mammals at the...

30 CFR 285.1016 - When will an Alternate Use RUE be cancelled?

Code of Federal Regulations, 2010 CFR

2010-07-01

... OFFSHORE RENEWABLE ENERGY ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Rights of Use and Easement for Energy- and Marine-Related Activities Using Existing OCS Facilities Alternate Use... marine, coastal, or human environment; or sites, structures, or objects of historical or archaeological...

30 CFR 585.906 - What must my decommissioning application include?

Code of Federal Regulations, 2012 CFR

2012-07-01

... include? 585.906 Section 585.906 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF... conducted in the vicinity of the structure and recent observations of turtles or marine mammals at the...

30 CFR 285.103 - When may MMS prescribe or approve departures from these regulations?

Code of Federal Regulations, 2011 CFR

2011-07-01

... from these regulations? 285.103 Section 285.103 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY ALTERNATE USES OF EXISTING..., or the marine, coastal, or human environment; or (4) Protect sites, structures, or objects of...

40 CFR 125.133 - What special definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 22 2014-07-01 2013-07-01 true What special definitions apply to this subpart? 125.133 Section 125.133 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil and Gas Extraction Facilities...

40 CFR 125.133 - What special definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 23 2013-07-01 2013-07-01 false What special definitions apply to this subpart? 125.133 Section 125.133 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil and Gas Extraction Facilities...

40 CFR 125.133 - What special definitions apply to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 23 2012-07-01 2012-07-01 false What special definitions apply to this subpart? 125.133 Section 125.133 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil and Gas Extraction Facilities...

40 CFR 80.82 - Butane blending.

Code of Federal Regulations, 2011 CFR

2011-07-01

...% aromatics≤2.0 vol% benzene≤0.03 vol% sulfur≤140 ppm until December 31, 2003; ≤120 ppm in 2004; ≤30 ppm... results demonstrate the butane has the following properties: olefins≤10.0 vol% aromatics≤2.0 vol% benzene...

40 CFR 80.82 - Butane blending.

Code of Federal Regulations, 2010 CFR

2010-07-01

...% aromatics≤2.0 vol% benzene≤0.03 vol% sulfur≤140 ppm until December 31, 2003; ≤120 ppm in 2004; ≤30 ppm... results demonstrate the butane has the following properties: olefins≤10.0 vol% aromatics≤2.0 vol% benzene...

An amperometric NO2 sensor based on La10Si5NbO27.5 electrolyte and nano-structured CuO sensing electrode.

PubMed

Wang, Ling; Han, Bingxu; Dai, Lei; Zhou, Huizhu; Li, Yuehua; Wu, Yinlin; Zhu, Jing

2013-11-15

A novel amperometric-type NO2 sensor based on La10Si5NbO27.5 (LSNO) electrolyte and nano-structured CuO sensing electrode was fabricated and tested. A bilayer LSNO electrolyte including both a dense layer and a porous layer was prepared by conventional solid state reaction method and screen-printing technology. The nano-structured CuO sensing electrode was in situ fabricated in LSNO porous layer by impregnating method. The composition and microstructure of the sample were characterized by XRD and SEM, respectively. The results showed that the CuO particles with diameters range of 200-500 nm were homogeneously dispersed on the LSNO backbone in porous layer. The sensor exhibited well sensing characteristics to NO2. The response current was almost linear to NO2 concentration in the range of 25-500 ppm at 600-800 °C. With increase of operating temperature, the sensitivity increased and reached 297 nA/ppm at 800 °C. The response currents toward NO2 were slightly affected by coexistent O2 (0-21 vol%) and CO2 (0-5 vol%). Copyright © 2013 Elsevier B.V. All rights reserved.

A Delay Vector Variance based Marker for an Output-Only Assessment of Structural Changes in Tension Leg Platforms

NASA Astrophysics Data System (ADS)

Jaksic, V.; Wright, C.; Mandic, D. P.; Murphy, J.; Pakrashi, V.

2015-07-01

Although aspects of power generation of many offshore renewable devices are well understood, their dynamic responses under high wind and wave conditions are still to be investigated to a great detail. Output only statistical markers are important for these offshore devices, since access to the device is limited and information about the exposure conditions and the true behaviour of the devices are generally partial, limited, and vague or even absent. The markers can summarise and characterise the behaviour of these devices from their dynamic response available as time series data. The behaviour may be linear or nonlinear and consequently a marker that can track the changes in structural situations can be quite important. These markers can then be helpful in assessing the current condition of the structure and can indicate possible intervention, monitoring or assessment. This paper considers a Delay Vector Variance based marker for changes in a tension leg platform tested in an ocean wave basin for structural changes brought about by single column dampers. The approach is based on dynamic outputs of the device alone and is based on the estimation of the nonlinearity of the output signal. The advantages of the selected marker and its response with changing structural properties are discussed. The marker is observed to be important for monitoring the as- deployed structural condition and is sensitive to changes in such conditions. Influence of exposure conditions of wave loading is also discussed in this study based only on experimental data.

Analysis of offshore platforms lifting with fixed pile structure type (fixed platform) based on ASD89

NASA Astrophysics Data System (ADS)

Sugianto, Agus; Indriani, Andi Marini

2017-11-01

Platform construction GTS (Gathering Testing Sattelite) is offshore construction platform with fix pile structure type/fixed platform functioning to support the mining of petroleum exploitation. After construction fabrication process platform was moved to barges, then shipped to the installation site. Moving process is generally done by pull or push based on construction design determined when planning. But at the time of lifting equipment/cranes available in the work area then the moving process can be done by lifting so that moving activity can be implemented more quickly of work. This analysis moving process of GTS platform in a different way that is generally done to GTS platform types by lifting using problem is construction reinforcement required, so the construction can be moved by lifting with analyzing and checking structure working stress that occurs due to construction moving process by lifting AISC code standard and analysis using the SAP2000 structure analysis program. The analysis result showed that existing condition cannot be moved by lifting because stress ratio is above maximum allowable value that is 0.950 (AISC-ASD89). Overstress occurs on the member 295 and 324 with stress ratio value 0.97 and 0.95 so that it is required structural reinforcement. Box plate aplication at both members so that it produces stress ratio values 0.78 at the member 295 and stress ratio of 0.77 at the member 324. These results indicate that the construction have qualified structural reinforcement for being moved by lifting.

Estimating the Economic Potential of Offshore Wind in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beiter, P.; Musial, W.; Smith, A.

The potential for cost reduction and market deployment for offshore wind varies considerably within the United States. This analysis estimates the future economic viability of offshore wind at more than 7,000 sites under a variety of electric sector and cost reduction scenarios. Identifying the economic potential of offshore wind at a high geospatial resolution can capture the significant variation in local offshore resource quality, costs, and revenue potential. In estimating economic potential, this article applies a method initially developed in Brown et al. (2015) to offshore wind and estimates the sensitivity of results under a variety of most likely electricmore » sector scenarios. For the purposes of this analysis, a theoretical framework is developed introducing a novel offshore resource classification system that is analogous to established resource classifications from the oil and gas sector. Analyzing economic potential within this framework can help establish a refined understanding across industries of the technology and site-specific risks and opportunities associated with future offshore wind development. The results of this analysis are intended to inform the development of the U.S. Department of Energy's offshore wind strategy.« less

Boundary Spanning in Offshored Information Systems Development Projects

ERIC Educational Resources Information Center

Krishnan, Poornima

2010-01-01

Recent growth in offshore outsourcing of information systems (IS) services is accompanied by managing the offshore projects successfully. Much of the project failures can be attributed to geographic and organizational boundaries which create differences in culture, language, work patterns, and decision making processes among the offshore project…

78 FR 63233 - National Offshore Safety Advisory Committee; Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-23

... Equipment in Hazardous Areas on Foreign Flag Mobile Offshore Drilling Units. (4) Safety Impact of Liftboat... Equipment in Hazardous Areas on Foreign Flag Mobile Offshore Drilling Units (MODUs); (d) Safety Impact of... DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket No. USCG-2013-0886] National Offshore Safety...

76 FR 78938 - Carpinteria Offshore Field Redevelopment Project-Developmental Drilling Into the Carpinteria...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-20

... DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management Carpinteria Offshore Field Redevelopment Project--Developmental Drilling Into the Carpinteria Offshore Field Oil and Gas Reserves... Lands Commission (CSLC) intend to jointly review a proposal to develop offshore oil and gas resources...