scholarly journals Influencing Factors of Motion Responses for Large-Diameter Tripod Bucket Foundation

2019 ◽  
Vol 9 (22) ◽  
pp. 4957 ◽  
Author(s):  
Xianqing Liu ◽  
Puyang Zhang ◽  
Mingjie Zhao ◽  
Hongyan Ding ◽  
Conghuan Le
Keyword(s):  
Water Depth ◽  
Large Diameter ◽  
Maximum Amplitude ◽  
Cost Effective ◽  
Offshore Wind ◽  
Pitching Motion ◽  
Bucket Foundation ◽  
Response Amplitude Operators ◽  
Effective Development ◽  
The Cost

Large-diameter multi-bucket foundation is well suited for offshore wind turbines at deeper water than 20 m. Air floating transportation is one of the key technologies for the cost-effective development of bucket foundation. To predict the dynamic behavior of large-diameter tripod bucket foundation (LDTBF) supported by an air cushion and a water plug inside every bucket in waves, three 1/25-scale physical model tests with different bucket spacing were conducted in waves; detailed prototype foundation models were established using a hydrodynamic software MOSES with a draft of 4.0 m, 4.5 m, and 5.0 m and with a water depth of 10.0 m, 11.25 m, and 12.5 m. The numerical and experimental results are consistent for heaving motion, while exhibiting favorable agreement for pitching motion. The results show that the resonant periods for heaving motion increased with increasing draft and water depth. The maximum amplitude for heaving motion first decreased and then increased with the increase of water depth and spacing between the buckets. The maximum amplitude for pitching motion first decreased and then increased with increasing water depth but decreased with increasing spacing between the buckets. The wider the spacing between the bucket foundations, the larger the heave response amplitude operators (RAOs). Simply improving the pitch RAOs by increasing the spacing between bucket foundations is limited and negatively affects motion performance during the transportation of LDTBF.

scholarly journals ANN-Based Decision Making in Station Keeping for Geotechnical Drilling Vessel

2021 ◽  
Vol 9 (6) ◽  
pp. 596
Author(s):  
Murugan Ramasamy ◽  
Mohammed Abdul Hannan ◽  
Yaseen Adnan Ahmed ◽  
Arun Kr Dev
Keyword(s):  
Decision Making ◽  
Water Depth ◽  
Business Models ◽  
Cost Benefit ◽  
Cost Effective ◽  
Station Keeping ◽  
Operational Information ◽  
Effective Option ◽  
The Cost ◽  
Cost Factors

Offshore vessels (OVs) often require precise station-keeping and some vessels, for example, vessels involved in geotechnical drilling, generally use Spread Mooring (SM) or Dynamic Positioning (DP) systems. Most of these vessels are equipped with both systems to cover all ranges of water depths. However, determining which system to use for a particular operational scenario depends on many factors and requires significant balancing in terms of cost-benefit. Therefore, this research aims to develop a platform that will determine the cost factors for both the SM and DP station-keeping systems. Operational information and cost data are collected for several field operations, and Artificial Neural Networks (ANN) are trained using those data samples. After that, the trained ANN is used to predict the components of cost for any given environmental situation, fieldwork duration and water depth. Later, the total cost is investigated against water depth for both DP and SM systems to determine the most cost-effective option. The results are validated using two operational scenarios for a specific geotechnical vessel. This decision-making algorithm can be further developed by adding up more operational data for various vessels and can be applied in the development of sustainable decision-making business models for OVs operators.

scholarly journals A Comparative Study between Three-Legged and Tripod Sub-structures in Design of Offshore Wind Turbines in the Transition Water Depth

2018 ◽  
Vol 7 (3.36) ◽  
pp. 23
Author(s):  
Aliakbar Khosravi ◽  
Tuck Wai Yeong ◽  
Mohammed Parvez Anwar ◽  
Jayaprakash Jaganathana ◽  
Teck Leong Lau ◽  
...  
Keyword(s):  
Water Depth ◽  
Limit State ◽  
Cost Effective ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Ultimate Limit State ◽  
Offshore Wind Turbines ◽  
Welding Joints ◽  
Fatigue Limit State ◽  
Ultimate Limit

This research aimed at investigating tripod and three-legged offshore wind turbine substructures. A comparison between the two substructures based on their weight as well as the installation method of piles, i.e. pre-piling and post-piling, was carried out. The in-place (Ultimate Limit State), Dynamic, natural frequency check and fatigue (Fatigue Limit State) analyses were conducted considering aerodynamic and hydrodynamic loads imposed on substructures in 50m water depth. An optimisation process was carried out in order to reduce the mass of substructures. The results revealed that the three-legged substructure is more cost effective with 25% lesser structure mass. However, the construction of the three-legged structure usually takes more time due to increased number of members and subsequently welding joints. The results, furthermore, showed that the pre-piling method reduces the time and cost of offshore installation, and reduces the weight of piles by 50%.  

scholarly journals ANN-Based Decision Making in Station Keeping for Geotechnical Drilling Vessel

2021 ◽  
Author(s):  
Murugan Ramasamy ◽  
Mohammed Abdul Hannan ◽  
Yaseen Adnan Ahmed ◽  
Arun Kr Dev
Keyword(s):  
Decision Making ◽  
Water Depth ◽  
Business Models ◽  
Cost Benefit ◽  
Cost Effective ◽  
Station Keeping ◽  
Operational Information ◽  
Effective Option ◽  
The Cost ◽  
Cost Factors

Offshore vessels (OVs) often requires precise station-keeping and some vessels, for example, vessel involves in geotechnical drilling generally use Spread Mooring (SM) or Dynamic Positioning (DP) systems. Most of these vessels are equipped with both systems to cover all ranges of water depths. However, determining which systems to use for a particular operational scenario depends on many factors and requires significant balancing in terms of cost-benefit. Therefore, this research aims to develop a platform that will determine the cost factors for both the SM and DP station keeping systems. Operational information and cost data are collected for several field operations, and Artificial Neural Networks (ANN) is trained using those data samples. After that, the trained ANN is used to predict the components of cost for any given environmental situation, fieldwork duration and water depth. Later, the total cost is investigated against water depth for both DP and SM systems to determine the most cost-effective option. The results are validated using two operational scenarios for a specific geotechnical vessel. This decision-making algorithm can be further developed by adding up more operational data for various vessels and can be applied in the development of sustainable decision-making business models for OVs operators.

scholarly journals Air-Floating Characteristics of Large-Diameter Multi-Bucket Foundation for Offshore Wind Turbines

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4108 ◽  
Author(s):  
Xianqing Liu ◽  
Puyang Zhang ◽  
Mingjie Zhao ◽  
Hongyan Ding ◽  
Conghuan Le
Keyword(s):  
Wind Turbines ◽  
Large Diameter ◽  
Added Mass ◽  
State Equation ◽  
Offshore Wind ◽  
Alternative Form ◽  
Bucket Foundation ◽  
Offshore Wind Turbines ◽  
Damping Characteristics ◽  
Oscillating Motion

In the present study, as a novel and alternative form of foundation for offshore wind turbines, the air-floating characteristics of a large-diameter multi-bucket foundation (LDMBF) in still water and regular waves are investigated. Following the theory of single degree of freedom (DOF)-damped vibration, the equations of oscillating motion for LDMBF are established. The spring or restoring coefficients in heaving, rolling and pitching motion are modified by a dimensionless parameter ϑ related to air compressibility in every bucket with the ideal air state equation. Combined with the 1/25 scale physical model tests and the numerically simulated prototype models by MOSES, the natural periods, added mass coefficients and damping characteristics of the LDMBF in free oscillations and the response amplitude operator (RAO) have been investigated. The results shown that the added mass coefficients between 1.2 and 1.6 is equal to or larger than the recommended values for ship dynamics. The coefficient 1.2 can be taken as the lower limit 1.2 for a large draft and 1.6 can be taken as the upper limit 1.6 for a small draft. The resonant period and maximum amplitudes for heaving and pitching motions decrease with increasing draft. The amplitudes of heaving and pitching movements decrease to a limited extent with decreasing water depth.

scholarly journals A Minimalistic Prediction Model to Determine Energy Production and Costs of Offshore Wind Farms

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 448
Author(s):  
Jens Nørkær Sørensen ◽  
Gunner Christian Larsen
Keyword(s):  
Prediction Model ◽  
Wind Turbines ◽  
Water Depth ◽  
Energy Production ◽  
Wind Farm ◽  
Cost Model ◽  
Wind Farms ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
The Cost

A numerical framework for determining the available wind power and associated costs related to the development of large-scale offshore wind farms is presented. The idea is to develop a fast and robust minimal prediction model, which with a limited number of easy accessible input variables can determine the annual energy output and associated costs for a specified offshore wind farm. The utilized approach combines an energy production model for offshore-located wind farms with an associated cost model that only demands global input parameters, such as wind turbine rotor diameter, nameplate capacity, area of the wind farm, number of turbines, water depth, and mean wind speed Weibull parameters for the site. The cost model includes expressions for the most essential wind farm cost elements—such as costs of wind turbines, support structures, cables and electrical substations, as well as costs of operation and maintenance—as function of rotor size, interspatial distance between the wind turbines, and water depth. The numbers used in the cost model are based on previous but updatable experiences from offshore wind farms, and are therefore, in general, moderately conservative. The model is validated against data from existing wind farms, and shows generally a very good agreement with actual performance and cost results for a series of well-documented wind farms.

scholarly journals Development and Transferability of Black and Red Raspberry Microsatellite Markers from Short-Read Sequences

2015 ◽  
Vol 140 (3) ◽  
pp. 243-252 ◽  
Author(s):  
Michael Dossett ◽  
Jill M. Bushakra ◽  
Barbara Gilmore ◽  
Carol A. Koch ◽  
Chaim Kempler ◽  
...  
Keyword(s):  
Ssr Markers ◽  
Massively Parallel Sequencing ◽  
Cost Effective ◽  
Black Raspberry ◽  
Red Raspberry ◽  
Short Read ◽  
Sequencing Technologies ◽  
Effective Development ◽  
The Cost ◽  
Simple Sequence

The advent of next-generation, or massively parallel sequencing technologies has been a boon to the cost-effective development of molecular markers, particularly in nonmodel species. Here, we demonstrate the efficiency of microsatellite or simple sequence repeat (SSR) marker development from short-read sequences in black and red raspberry (Rubus occidentalis L. and R. idaeus L., respectively), compare transferability of markers across species, and test whether the rate of polymorphism in the recovered markers can be improved upon by how marker sequences are chosen. From 28,536,412 black raspberry reads and 27,430,159 reads in red raspberry, we identified more than 6000 SSR sequences in each species and selected 288 of these (144 from each species), for testing in black and red raspberry. A total of 166 SSR primer pairs were identified with informative polymorphism in one or both species. SSRs selected based on different percentages (90% to 97% as compared with ≥98%) of read cluster similarity did not differ in polymorphism rates from each other or from those originating from singletons. Efficiency of polymorphic SSR recovery was nearly twice as high in black raspberry from black raspberry-derived sequences as from red raspberry-derived sequences, while efficiency of polymorphic SSR recovery in red raspberry was unaffected by the source of the primer sequences. Development of SSR markers that are transferable between red and black raspberry for marker-assisted selection, evaluation of genome collinearity and to facilitate comparative studies in Rubus L. will be more efficient using SSR markers developed from black raspberry sequences.

SHARED INFRASTRUCTURE: A COST-EFFECTIVE DEVELOPMENT STRATEGY FOR SMALLER FIELDS OFFSHORE AUSTRALIA?

2004 ◽  
Vol 44 (1) ◽  
pp. 569
Author(s):  
B.F. Ronalds
Keyword(s):  
Shallow Water ◽  
Development Strategy ◽  
Water Depth ◽  
New Technology ◽  
Cost Effective ◽  
Oil Fields ◽  
Field Conditions ◽  
Oil Companies ◽  
Effective Development ◽  
Shared Infrastructure

B.F. RonaldsFuture oil discoveries offshore Australia are unlikely to be large fields that can support the development of a one-off self-sufficient facility. Fixed platforms are generally only feasible in shallow water when the water depth (in metres) to well count ratio d/w The construction and ongoing re-use of a generic FPSO suited to Australasian field conditions might be of considerable assistance in monetising small oil fields in deeper water. Similarly, aptly located, designed and operated gas hubs could open up large areas for satellite gas development long into the future, aided by new technology to enable ultra-long tiebacks. Both approaches suggest the benefit of overlaying a regional perspective on the oil companies’ field-specific development philosophy.

Modeling Large Diameter Industrial Pipe Insulation Performance

2021 ◽  
Vol 263 (5) ◽  
pp. 1555-1560
Author(s):  
Kevin Herreman
Keyword(s):  
Large Diameter ◽  
Small Diameter ◽  
Cost Effective ◽  
Noise Emission ◽  
Cost Effective Method ◽  
Diameter Pipe ◽  
Insulation Systems ◽  
The Cost ◽  
Pipe Insulation ◽  
Insulation Performance

As previously presented, reducing industrial noise emission utilizing jacketed pipe insulation is critical to reducing noise in industrial spaces. The ISO 15665 standard defines a testing process for measurement of the acoustical performance of installed and jacketed pipe insulation systems. To provide a cost-effective method for evaluating various types of multilayered jacketed pipe insulation a model was developed. The model accurately estimates the performance of single, and multilayered, jacketed pipe insulation. Validating the use of the model to very large pipe diameters is highly desirable as the cost to test is significantly higher than testing the medium or small diameter pipe insulation. The estimated insertion loss result from the model is compared to validation testing results for large diameter jacketed pipe insulation are reported herein.

The IBM-PC in electron microscopy

1996 ◽  
Vol 54 ◽  
pp. 612-613
Author(s):  
James F. Mancuso
Keyword(s):  
Head Start ◽  
Image Acquisition ◽  
Cost Effective ◽  
Financial Applications ◽  
Number Of Factors ◽  
Instrument Control ◽  
The Cost ◽  
Training And Support ◽  
Control Image ◽  
Ibm Pc

IBM PC compatible computers are widely used in microscopy for applications ranging from control to image acquisition and analysis. The choice of IBM-PC based systems over competing computer platforms can be based on technical merit alone or on a number of factors relating to economics, availability of peripherals, management dictum, or simple personal preference.IBM-PC got a strong “head start” by first dominating clerical, document processing and financial applications. The use of these computers spilled into the laboratory where the DOS based IBM-PC replaced mini-computers. Compared to minicomputer, the PC provided a more for cost-effective platform for applications in numerical analysis, engineering and design, instrument control, image acquisition and image processing. In addition, the sitewide use of a common PC platform could reduce the cost of training and support services relative to cases where many different computer platforms were used. This could be especially true for the microscopists who must use computers in both the laboratory and the office.

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