Day 4 Thu, August 19, 2021最新文献

{"title":"Hull Condition Monitoring and Lifetime Estimation by the Combination of On-Board Sensing and Digital Twin Technology","authors":"T. Sugimura, Shunsaku Matsumoto, Soichiro Inoue, Shingo Terada, S. Miyazaki","doi":"10.4043/30977-ms","DOIUrl":"https://doi.org/10.4043/30977-ms","url":null,"abstract":"\u0000 The industries using floating facilities such as FPSO and offshore wind turbine are increasing. Since these vessels have been fixed and operated in the installed area for a long period of time, they cannot be regularly docked, inspected and repaired as opposed to normal ship case, and limited to the inspection of the hull outer plates from under the water and the inspection of inside the tanks are conducted once every five years. These inspections involving visual inspections and thickness measurements at representative points, only examine the current state, and don’t evaluate quantitatively the future potential (remaining life) over the subsequent long operation period. To predict residual life in order to maintain the integrity of these structures, digital twin technology is proposed to realize this demand. This paper shows the method to develop digital twin assessment which solve the insufficiency of conventional monitoring and simulation method in order to utilize for risk-based inspection (RBI) and condition-based maintenance (CBM) to the operators.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73745107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lateral Buckling Mitigation in Deep Waters - A Total Installed Costs Comparison","authors":"Hemant Priyadarshi, Matthew D Fudge, M. Brunner, Seban Jose, C. Weakly","doi":"10.4043/30969-ms","DOIUrl":"https://doi.org/10.4043/30969-ms","url":null,"abstract":"\u0000 The paper introduces lateral buckling mitigation techniques (sleepers, distributed buoyancy sections, and residual curvature method or RCM) used in deep water fields and provides a total installed cost comparison of these solutions in relative terms. A hypothetical deep-water scenario is used to compare all techniques within the same site environment. Historic benchmarks have been used to make a relative comparison of these buckle mitigation methods on the engineering, procurement, fabrication, and installation fronts.\u0000 In addition, risks associated with engineering, procurement/fab and installation have been listed to illustrate the risks versus rewards tradeoff. While sleepers and distributed buoyancy have been previously used in deep water, RCM doesn't have a significant track record yet. RCM is a proven and cost-effective buckle mitigation solution in shallow water. This paper compares its application in deep water to the prevailing buckle mitigation methods and confirms if it creates value (savings and reduces risks) for an offshore installation project. It is assumed that each mitigation method is appropriate for the hypothetical deep-water scenario.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86257486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Use of Digital Solutions to Enable New Health Care Services on Calm Buoys","authors":"Antoine Jeannin, Rodrigo Vieira Camara de Castro, Jonathan Peter, Sebastien de Tessieres","doi":"10.4043/31126-ms","DOIUrl":"https://doi.org/10.4043/31126-ms","url":null,"abstract":"\u0000 Offshore fields present a growing need to guarantee safety and productivity while minimizing operational costs and increasing remote assistance. Brownfields are more exposed to risks due to the presence of aged assets requiring in depth inspections to assess potential life extensions. This challenge was tackled with a comprehensive approach to asset integrity management based on the enhanced use of digital solutions to enable new health care services on offshore assets, like CALM Buoys.\u0000 In line with the recent Oil & Gas industry trends, new digital technologies have been recently developed and deployed on board our fleet of CALM (Catenary Anchor Leg Mooring) Buoys, such as the 3C Telemetry system, Inspection Tablets, the IDEA Web Portal and the Marine Drone. All these new digital solutions will be presented in the proposed paper concerning their technical capabilities and the overall integrity performance improvements achieved with their enhanced use on offshore assets.\u0000 The 3C Telemetry system converts and upgrades CALM Buoys into smart, internet-friendly offloading terminals, connecting the system to Cloud services and ensuring secured data transmission, treatment, storage, and privacy, while delivering reliable accurate information to operators anywhere in the world. Inspection tablets are used to optimize health check campaigns on Buoys with a real-time and remote back office engineering support. These systems can also be connected to the IDEA (Imodco Digital Experience Access) Web Portal to allow online data visualization and analysis of the mooring systems performance.\u0000 \"The Marine Drone is an unmanned survey vehicle to perform diverless UWILD (Underwater Inspection in Lieu of Dry-docking). The system can perform in depth visual inspections with its ROV (Remotely Operated Vehicle) and high-resolution subsea layout mapping of CALM buoys’ structures with its 3D bathymetry system, all providing high quality digital data post processed by advanced analytical tools for integrity analysis and preventive maintenance planning\" (Castro, R., et al. 2020).\u0000 Data management has become the most valuable asset for companies seeking to have a better understanding and to continuously improve operations. This paper will demonstrate how Buoys and passive (process wise) equipment, like Turrets, can be operated in new ways: 1. Connected Asset (IoT): 3C Telemetry, Tablets, and the Marine Drone. 2. Platform to share/connect data to algorithms/users: IDEA System. 3. New operating business models enabled by health care approach.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88326892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Digital Twin For Offshore Pipeline Corrosion Monitoring: A Deep Learning Approach","authors":"S. Bhowmik","doi":"10.4043/31296-ms","DOIUrl":"https://doi.org/10.4043/31296-ms","url":null,"abstract":"\u0000 Pipeline corrosion is a major identified threat in the offshore oil and gas industry. In this paper, a novel computer vision-based digital twin concept for real-time corrosion inspection is proposed. The Convolution Neural Network (CNN) algorithm is used for the automated corrosion identification and classification from the ROV images and In-Line Inspection data. Predictive and prescriptive maintenance strategies are recommended based on the corrosion assessment through the digital twin.\u0000 A Deep-learning Image processing model is developed based on the pipeline inspection images and In-Line Inspection images from some previous inspection data sets. During the corrosion monitoring through pipeline inspection, the digital twin system would be able to gather data and, at the same time, process and analyze the collected data. The analyzed data can be used to classify the corrosion type and determine the actions to be taken (develop predictive and prescriptive maintenance strategy). Convolution Neural Network, a well known Deep Learning algorithm, is used in the Tensorflow framework with Keras in the backend is used in the digital twin for corrosion inspection. CNN algorithm will first detect the corrosion and then the type of corrosion based on image classification. The deep-learning network training is done using 4000 images taken from the inspection video frames from a subsea pipeline inspection using ROV. The performances of both the methods are compared based on result accuracy as well as processing time.\u0000 Deep Learning algorithm, CNN has approximately 81% accuracy for correctly identifying the corrosion and classify them based on severity through image classification. The processing time for the deep-learning method is significantly faster, and the digital twin generates the predictive or prescriptive strategy based on the inspection result in real-time.\u0000 Deep-learning based digital twin for Corrosion inspection significantly improve current corrosion identification and reduce the overall time for offshore inspection. The inspection data loss due to the communication interference during real-time assessment can be eliminated using the digital twin. The image data can recover the required features based on other features available through the previous inspection. Furthermore, the system can adapt to the unrefined environment, making the proposed system robust and useful for other detection applications. The digital twin makes a recommended decision based on an expert system database during the real-time inspection.\u0000 The complete corrosion monitoring process is performed in real-time on a cloud-based digital twin. The proposed pipeline corrosion inspection digital twin based on the CNN method will significantly reduce the overall maintenance cost and improve the efficiency of the corrosion monitoring system.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87049167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Troll Phase 3: The Next Step for a Groundbreaking Giant","authors":"Bjørn Laastad, Knut Ellevog, Roger Oen Jensen, Tor-Martin Tveit, Eirik Torgrimsen, Ingmar Jensen","doi":"10.4043/30954-ms","DOIUrl":"https://doi.org/10.4043/30954-ms","url":null,"abstract":"\u0000 An important driver for maximizing value creation for the Troll Phase 3 gas project offshore Norway was to identify means to reduce the pressure drop in the value chain from the reservoir to the onshore terminal. Using a design-to-cost approach in the concept selection phase, this has affected design of the wells, subsea production system, pipeline and the new inlet separator on the Troll A platform; all of which have been designed to preserve the energy from the reservoir as much as possible. The final design has enabled a significant increase of the project value by accelerated gas deliveries, reduction of the energy consumption and thus lowering the CO2 emissions.\u0000 Calculations show that 1 bar pressure drop in the Troll Phase 3 value chain increases the project NPV (8%, pretax) with approx. 45 Million USD and reduces the power consumption by 11 GWh/year.\u0000 The well tubing size was increased to 9 5/8\", reducing the required number of wells by ~40%. Factoring both wells and subsea facilities, this optimized well concept alone represents a total cost saving of nearly 300 million USD. The project has piloted a modification to the Vertical X-Mas Tree (VXT) design featuring an increase from 5 1/8\" to a 7\" production wing outlet to minimize the pressure drop across the subsea production system. This VXT design has become the new company standard for gas field developments. The big bore wells and subsea production system design also ensures acceptable gas velocities in the late production phase with low reservoir pressure.\u0000 The total reduced pressure drop obtained through these and other measures is estimated to 19 bar, realizing a project NPV improvement of approx. 850 million USD (8%, pretax).","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91003262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solving Decommissioning and Abandonment Problems When Planning to Shear 9 5/8-inch Casing in a 13 5/8-inch × 10k RAM BOP","authors":"D. E. Cain, K. Klopfenstein, James Robert McMullan","doi":"10.4043/31062-ms","DOIUrl":"https://doi.org/10.4043/31062-ms","url":null,"abstract":"\u0000 A decommissioning and abandonment requirement to shear 9 5/8-inch casing in certain circumstances with a 13 5/8-inch × 10,000 psi rated working pressure, RWP, Shear RAM type blowout preventer, BOP, resulted in a need to develop a novel casing shear device and shear calculation method. Results of shear testing, future engineering planning guidance, the new shear calculation method, and comparison to legacy technology are included in this paper.\u0000 Interaction with the end user to understand requirements, a five-step problem solving procedure, a basis of design process, materials justification, verification analysis, validation testing, and describing an improved shear operator force/pressure calculation are all described. Shear larger casing in the required and restrictive RAM BOP and well bore presented a problematic challenge. Equally, tubular fish size was required to support fishing extraction operations following shear. Validation test results exceeded requirements and resulted in the need for a new approach to the shear calculation method.\u0000 The novel shear RAM geometry was developed utilizing shear calculation methods which were based on legacy considerations. API 16A shear validation procedures and two legacy shear calculation methods where employed. Shear calculations are used to anticipate the RAM BOP operator pressures required to shear a specific tubular. The larger than historically allowed casing size to be sheared in a 13 5/8-inch × 10,000 psi RAM BOP meant higher operator pressures were anticipated for each operator option. A Novel shear RAM geometry was developed as a design intent to lower shear force/pressure. There was an observation during validation testing that the geometry exceeded expectations to lower shear pressure significantly. This observation led to a conclusion that an improved shear calculation method was required for this application. This novel calculation method description / statistical treatment, test results, RAM design methods, and tabular shear engineering planning information are included in this paper.\u0000 One additional requirement of the shear RAM geometry was to provide an upper and lower fish deformed surface which could be easily retrieved thru the 13 5/8-inch BOP bore. An additional observation was that the fish width requirement was achieved.\u0000 The novel shear calculation method allows an engineer to precisely plan for bonnet actuation pressures when larger casing is sheared. The precise calculation of shear force/pressure also assists with BOP operator size and type selection. The engineer will gain casing size versus shear pressure for specific operator options in tabular format. Planners will gain insight into tubular fish deformation estimation allowing mitigation of tubular extraction risk during operations planning.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88796964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slugging Fatigue Assessment for Steel Lazy Wave Risers","authors":"B. Campbell, P. Agarwal, Christopher E. Curtis, Guangqiang Yang, Angshuman Singha, Kathleen Casstevens, Gizem Ersoy Gokcal","doi":"10.4043/30922-ms","DOIUrl":"https://doi.org/10.4043/30922-ms","url":null,"abstract":"\u0000 The objective of this paper is to introduce a new analysis methodology for assessment of riser fatigue due to slugging. Under certain flow regimes, a multiphase (oil-gas-water) flow can result in slug flow, in which a sequence of relatively high density slugs and relatively low density bubbles propagate along the flowline and the riser. The variation of slug and bubble density at a location with time is random, and slug characteristics can also change significantly along the riser length. Due to local and global weight variations, the riser undergoes cycles of bending which cause fatigue. By explicitly modeling full spatial and temporal variability and randomness of slugs, the new analysis method is significantly more accurate than other methods and it captures physics of riser's slugging response.\u0000 The slugging fatigue of a steel lazy wave riser was analyzed in Orcaflex software by modeling a repeating pair of slug and bubble with constant slug and bubble densities and associated lengths over the 3-hour simulation time. A separate slug train was propagated in five sub-segments of the riser. To model a more accurate and realistic representation of slugging behavior, the time series of density was extracted at each node from the multiphase flow simulator Olga. Statistical and spectral analysis of the Olga output showed that assumptions of constant slug-bubble density, and of slug behavior being uniform over long segments of riser are too simplistic. Therefore, full time series of density at each node was input into the riser analysis using the existing capabilities of Orcaflex software. As the Orcaflex slug form approach was computationally expensive, we also developed an extrenal slug loader, which provides same level of accuracy while being computationally fast and full automated.\u0000 The new method shows that the cyclic riser response at the touchdown point (TDP) is composed of two parts. One is the relatively short period (~20-60 seconds) fluctuations that occur because of local weight variations as a slug-bubble passes a riser node. The other is the relatively long period (~10-30 minutes) fluctuations that occur due to global weight variations, which are due to spatial integration of density time series over the lower catenary. These long period fluctuations drive the TDP fatigue. Preliminary field measurements with an ROV, while inducing temporary slugging in the riser, confirmed analytical predictions of long period and high amplitude motions at hog bend.\u0000 This paper presents a new and significantly more accurate method for analyzing riser fatigue due to slugging. Previously unknown behavior of very long period and high amplitude riser motions is identified and explained. SLWR response to slugging can be an important contributor to the overall fatigue design budget especially at the TDP. This work reflects ExxonMobil's on-going efforts to ensure that we maintain safe designs as we adopt systems new to us in new and challenging environments.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89188872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decommissioning Offshore Structures by Extraction of Foundation Mono piles Applying a Vibratory Hammer","authors":"Rob van Dorp, P. Middendorp, M. Bielefeld, G. Verbeek","doi":"10.4043/31006-ms","DOIUrl":"https://doi.org/10.4043/31006-ms","url":null,"abstract":"\u0000 The vibratory hammer is one of the tools for the extraction of offshore foundation piles as well as monopiles for the decommissioning of offshore structures. In addition to the standard application, where a pile is driven downward to be installed, a vibratory hammer can also be applied to extract piles. For an efficient and commercially attractive application of vibratory hammers for this purpose, the extraction process needs to be modeled during the planning phase to ensure that the appropriate equipment is used. This paper describes how pile driving simulation software can be used to model the extraction process. This is further illustrated through a case study covering the extraction phase of the 1st (onshore) and 2nd (offshore) part of the Delft Offshore Turbine Project. A monopile with a diameter of 4.0 m was extracted approximate 6 months after installation onshore and then extracted several times offshore shortly after installation in the 2nd phase. The paper will not only present the actual extraction predictions, but also the monitoring data obtained during extraction and the results of the post-analysis.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88268874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensor Ball: Autonomous, Intelligent Logging Platform","authors":"E. Buzi, H. Seren, M. Deffenbaugh, Y BukhamseenAhmed, Mohamed Larbi Zeghlache","doi":"10.4043/31149-ms","DOIUrl":"https://doi.org/10.4043/31149-ms","url":null,"abstract":"\u0000 Recent developments in automation and electronics have enabled modernization and miniaturization of oilfield instruments. One product of these trends is our autonomous logging platform called \"Sensor Ball\". The Sensor Ball is a handheld, untethered logging tool that one person can deploy and recover from a pressurized well with no special equipment and crews (Deffenbaugh, 2016). The only tool needed is a wrench to open the cap of the wellhead. The operator puts the sensor ball in through the cap, then sequentially opens and closes the crown and master valves. This process takes only a few minutes. Once clear of the well head, the Sensor Ball falls down the well, logging data as it travels downhole. During this time, all the wellhead valves are closed and there is no need for the field crew to stay at the well site. We present data from recent Sensor Ball deployments to log pressure and temperature profiles and bottom-hole pressures. Depth information is provided by a novel onboard sensor that detects the connections between casing or tubing joints like a casing collar locator. A small dissolvable metal weight is magnetically attached to the housing and is sized to make the Sensor Ball descend at about 1 foot per second. At the desired depth, Sensor Ball drops the weight to become buoyant in the wellbore fluids and return to the surface. As it returns, it repeats the logging measurements, storing temperature and pressure data in its internal memory. After a typical four-to-eight hour mission, the operator returns to the well, opens and closes the well head valves in reverse order, removes the cap and takes out the Sensor Ball. The logged data are downloaded wirelessly to a laptop or cell phone. A lightweight, syntactic foam housing provides buoyancy and protects the electronics from the well fluids. The small thermal mass of the housing minimizes the temperature distortion in the downhole environment. This miniaturized technology simplified logging to a one-person job and shortened the time at the well from multiple hours to a few minutes.\u0000 This work describes a novel method of retrieving downhole data, which is a practical and inexpensive alternative to wireline or slickline logging and permanently-installed sensors (Deffenbaugh, 2017). In this paper we present the system design and our recent field results from vertical and deviated wells. We also describe a new application of the Sensor Ball where we perform extended bottom-hole pressure measurements in addition to logging temperature and pressure along the wellbore.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81069695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Subsea Chemicals Storage Solution Based on Liquid Barriers","authors":"M. Simionato, C. Giudicianni","doi":"10.4043/31290-ms","DOIUrl":"https://doi.org/10.4043/31290-ms","url":null,"abstract":"\u0000 This paper presents a solution for subsea storage of chemicals, where the conventional solid barriers between the chemical and sea water are replaced by a liquid layer, forming a liquid stacking tower inside a vertical tank. It can deal with most of the chemical formulations, providing a pressure balanced system based on barriers that are inherently damage-free. The storage units are easy to integrate and maintain as their design is simple. The benefits of the technology are discussed, also providing an overview of the ongoing qualification programme.","PeriodicalId":11084,"journal":{"name":"Day 4 Thu, August 19, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76811889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}