Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition最新文献

{"title":"Defect Localization for Pressure Vessel Based on Circumferential Guided Waves: An Experimental Study","authors":"Shuangmiao Zhai, Chaofeng Chen, Gangyi Hu, Shaoping Zhou","doi":"10.1115/PVP2018-85108","DOIUrl":"https://doi.org/10.1115/PVP2018-85108","url":null,"abstract":"Pressure vessels are normally employed under extreme environments with high temperature and high pressure. Inevitably, the defects like crack and corrosion that easily occur in the equipment and can significantly influence the normal operation. Guided wave-based method is a cost-effective means to measure the utility of pressure vessel. In this paper, finite element (FE) simulation is used to explore the propagation characteristics of circumferential guided waves in pressure vessel. Based on the propagation characteristics, the experiments with different configurations of piezoelectric transducers (PETs), which contain a sparse array and a dense array, have been conducted on pressure vessel respectively. Different imaging methods, including discrete ellipse imaging algorithm and probability damage imaging algorithm have been applied to locate the defect based on the configurations above. Furthermore, a multi-channel ultrasonic guided wave detection system has been set up for pressure vessel inspection. The experimental results show that the sparse array with the discrete ellipse imaging algorithm can locate the defect effectively. The imaging results based on probability damage imaging algorithm show that the dense array presents the better localization result.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114214557","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":"Fatigue Life Analysis of Storage Tanks In-Service Based on Exponential Curve Settlement Prediction Model","authors":"Delin Zhang, Zhiping Chen, You Li","doi":"10.1115/PVP2018-84431","DOIUrl":"https://doi.org/10.1115/PVP2018-84431","url":null,"abstract":"In order to study the structural fatigue safety of in-service fixed roof storage tanks after uneven settlement, an exponential curve method of settlement prediction has been constructed. A finite element model based on the contact condition between the elastic ring beam foundation and the tank base was also proposed. On the basis of above, a fatigue life prediction method of in-service storage tanks based on the settlement prediction model has been established. Combined with the engineering example of an in-service tank, the structural fatigue safety under the actual uneven settlement was analyzed. The results indicate that the trend of foundation settlement with time could be predicted accurately and the contact condition between base and foundation could be simulated simultaneously. Subsequently, the in-service tank’s structural fatigue life under the uneven settlement could be predicted.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127508731","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":"The Effect of a Low Constraint Geometry on Measured T0 Values for a Nuclear Reactor Pressure Vessel Ferritic Steel","authors":"Geena K. Rait, C. Davies, S. Garwood","doi":"10.1115/PVP2018-84167","DOIUrl":"https://doi.org/10.1115/PVP2018-84167","url":null,"abstract":"Current requirements for assessing the fracture toughness of reactor pressure vessel (RPV) ferritic steels are potentially overly conservative due to the employment of high constraint geometries such as compact tension (C(T)) or single edge notch bend, SEN(B), specimens for material testing. These high constraint conditions are not representative of the actual conditions experienced by the RPV in service. If this conservatism could be reduced, more appropriate predictions for RPV lifetime extension could become a possibility. In this study, a known low constraint geometry, single edge notch tension, SEN(T), has been tested alongside the higher constraint SEN(B) specimen in order to compare measured T0 and fracture toughness values for both cases. Finite element analyses have also been conducted for both geometries in order to measure T-stress and calculate Q values thereby allowing quantification of the level of constraint for both geometries. Eight SEN(B) and eight SEN(T) specimens were tested with dimensions 24 × 254 × 96 mm and 20 × 20 × 200 mm, respectively.\u0000 Testing was conducted at sub-zero temperatures, as close to the T0 as possible, in accordance with the guidelines presented in ASTM E1921-17a. Contrary to expected behaviour the SEN(T) specimen indicated a higher (less negative) T0 then the SEN(B) specimen. The reason for these results are explored in this paper.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116019985","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":"Application of T-Scaling Method to Account for the Effects of Notch Acuity on Notch Fracture Toughness in the Ductile-to-Brittle Transition Temperature Region","authors":"Hiroki Nakano, T. Meshii","doi":"10.1115/PVP2018-84165","DOIUrl":"https://doi.org/10.1115/PVP2018-84165","url":null,"abstract":"Current defect assessment procedures based on fracture mechanics usually assume flaws to be infinitely sharp. While this assumption may be appropriate for fatigue cracks, for non-sharp flaws such as porosity, mechanical damage, or weld undercut, it can be an over-conservative assumption that can lead to pessimistic assessments of structural integrity and a significant underestimation of the true safety margin against fracture. Irwin studied notched and pre-cracked fracture toughness in the lower shelf region and suggested that notched KIc, which is linear-elastic plane-strain fracture toughness is proportional to the square root of notch radius ρ but is not continuous with pre-cracked KIc (i.e., when zero is substituted by ρ in the fitted KIc and ρ relationship, the obtained value differs from that of the pre-cracked specimen KIc). In contrast, Begley et al. conducted a similar study in the upper shelf region and suggested that JIc ∝ ρ In addition, they showed that notched JIc is continuous with pre-cracked JIc. Very few studies have been conducted on this topic in the ductile-to-brittle transition temperature (DBTT) region. In this study, the effects of notch acuity on notch fracture toughness in the lower shelf and DBTT regions were studied for 0.55% C steel JIS S55C with 0.5TSE(B) specimens. The notch sizes ρ were selected as 50, 150, and 375 μm. Fatigue pre-cracked specimens were also studied. The experimental results showed that notched KIc ∝ ρ1/2 but is not continuous with the pre-cracked KIc at a lower shelf temperature of −166 °C. The DBTT notch fracture toughness KJc ∝ ρ1/2 and is continuous with the pre-cracked KJc. By conducting elastic-plastic finite element analysis (EP-FEA), the mid-plane crack-opening stress distribution on the x1-axis, was shown that the scaled stress distribution at fracture load was identical for pre-cracked and notched specimens. Thus, notched and pre-cracked KJc has a reason to be continuous. The reason for notch size effect on Jc was explained as the difference in load for notched specimens to reach the stress level of the pre-cracked specimen.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116610146","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 Seismic Vulnerability Analysis of a Liquefied Natural Gas Subplant","authors":"Massimiliano Pedot, R. D. Filippo, O. Bursi","doi":"10.1115/PVP2018-84731","DOIUrl":"https://doi.org/10.1115/PVP2018-84731","url":null,"abstract":"“Special risk” industrial plants can be highly vulnerable when subjected to natural phenomena such as earthquakes, flooding and explosions. In this study we focused our attention on the performance of a liquefied natural gas (LNG) terminal subjected to extreme earthquakes; an LNG terminal consists of a series of process facilities connected by pipelines of various sizes carrying hazardous chemical components. Although tanks, pipes, elbows, bolted flanges have been a major concern in terms of seismic design, generally, they have not been analyzed with modern performance-based procedures. Thus, our work has been devoted to the assessment, within the performance-based earthquake engineering (PBEE) framework, of the seismic performance of tanks, pipes, elbows and bolted flange joints by means of seismic fragility functions. Particular attention was paid to component resistance and to loss of containment (LoC) due to leakage.\u0000 A representative case study of an LNG terminal has been selected and tank, support structures and pipework, including elbows and flanges were analyzed with a detailed 3D finite elements model. Preliminary analyses identified elbow and bolted flange joints as critical components. A mechanical model, based on experimental data, defines leakage limit states for bolted flange joints. A significant effort was also devoted to identification of a leakage limit state for piping elbows, and we found the level of the hoop plastic strain to be an indicator.\u0000 On a first stage for the probabilistic seismic demand analysis (PSDA) we applied the Cloud method, due to its advantages in terms of consistency in the seismic input and of computational savings. More precisely, we studied the behaviour of critical components using a set of 36 ground motions, selected from a database of historic earthquake accelerations. The results of seismic analysis show that bolted flange joints remain significantly below their leakage threshold while elbows at the top of the LNG tank are likely to show LoC. Fragility functions show that elbows located on the tank platform are relatively unsafe against earthquakes.\u0000 On a second stage, in order to detect more complex failure scenarios, we analysed an LNG plant comprising a more complex piping substructure with respect to the original FE model. Moreover, we have treated the LoC of elbows from a probabilistic point of view by means of a Gaussian probability density function associated to a hoop strain limit state. The results provided by the aforementioned refined piping system allow for an improved and more accurate seismic risk assesment of the LNG plant.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"599 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123426051","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":"Development of Degradation Management System for Bottom Plate Coating of Oil Storage Tank Using New Parameters","authors":"D. Ito, K. Sekino, S. Okazaki, K. Sekine, Masaru Ishihara","doi":"10.1115/PVP2018-85000","DOIUrl":"https://doi.org/10.1115/PVP2018-85000","url":null,"abstract":"In Japan, according to the national policy, oil is stockpiled to keep the life of the people around 180 days. Stockpiling method are ground base tank, marine base tank, and underground bedrock base tank. Especially, the inspection of the ground tank is carried out every 8 years by Fire Defense Law. A high performance organic coating is used as the corrosion protection for inner bottom plate of the tank. Regarding the degradation of the coating, blisters and scratches are mainly found by visual inspection. In addition, as a non-destructive inspection of the degradation level of the coating, there is an evaluation using the tanδ1–2) value by the electrochemical impedance method. However, the tanδ value is the result of only one frequency region, and complicated degradation phenomenon cannot be explained. Therefore, in this study, two Constant Phase Element (CPE)3)-5) parameters were applied to the equivalent circuit analysis. CPE is a distributed constant element and may replace complicated degradation phenomena. We designed the elements separately for overall slow degradation phenomena (soundness) and specific degradation phenomena (damage). As a result of analysis based on the analysis parameter (T, p) using the data of the inspection of actual tanks, the characteristics of each tank could be evaluated with new indices.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121496704","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":"Experimental Determination of the Static Equivalent Pressures of Detonative Explosions of Ethylene/O2/N2-Mixtures and Cyclohexane/O2/N2-Mixtures in Long and Short Pipes","authors":"H. Schildberg","doi":"10.1115/PVP2018-84493","DOIUrl":"https://doi.org/10.1115/PVP2018-84493","url":null,"abstract":"In the recent past (PVP2013-97677, PVP2014-28197, PVP2015-45286, PVP2016-63223) we had started to determine the static equivalent pressures (pstat) of the eight detonative pressure scenarios in long and short pipes for different detonable gas mixtures. The pstat-values are of vital importance for process design: by assigning static equivalent pressures to the highly dynamic detonative pressure peaks it is possible to apply the established pressure vessel guidelines, which can only cope with static loads, in the design of detonation pressure resistant pipes. In the previous publications the parameter R was defined as the ratio between pstat at the location where transition from deflagration to detonation occurs and pstat in the region of the stable detonation. One important finding was that R depends on the reactivity of the gas mixture. So far, R cannot be predicted from first principles or from combustion parameters, but can only be determined experimentally. The ratio R has a special significance, because it not only determines pstat for the Deflagration to Detonation Transition (DDT) in long pipes (first detonative pressure scenario), but also gives a good estimate for two of the three scenarios relevant in the design of short pipes: DDT and the coalescence of DDT and reflection.\u0000 The present paper concludes the test series conducted at BASF during the last 4 years. It presents additional experimental data showing the variation of R over the entire detonative range of Ethylene/O2/N2 mixtures and along the stoichiometric line of Cyclohexane/O2/N2 mixtures. Based on the variation of R for these ternary mixtures and for the mixtures presented in the preceding publications, a typical variation of R for a general combustible/O2/N2-mixture is estimated over the entire explosive range. By means of this estimation the static equivalent pressures of the six design-relevant detonative pressure scenarios of any combustible/O2/N2-mixture can now be derived combining the parameter R with the Chapman-Jouguet pressure ratio, which can be calculated in a straightforward manner from thermodynamic properties.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126896862","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":"Creep Fatigue Damage Assessment of V-Butt Weld Pipe With an Extended Direct Steady Cycle Analysis","authors":"M. Puliyaneth, Haofeng Chen, Weiling Luan","doi":"10.1115/PVP2018-84568","DOIUrl":"https://doi.org/10.1115/PVP2018-84568","url":null,"abstract":"One of the methods to increase the efficiency of power plants is by increasing their operating temperature, this can lead to various damage mechanisms due to creep-cyclic plasticity interactions such as creep ratcheting, cyclically enhanced creep and creep enhanced plasticity. In the presence of welds, their assessments are complicated due to the presence of different material zones, namely parent metal, weld metal and heat affected zone which exhibit different properties. This paper aims at investigating the creep-fatigue damage of a V-butt welded pipe under a constant mechanical load and a cyclic temperature load, considering full interaction between creep and cyclic plasticity using the extended Direct Steady Cycle Analysis (eDSCA) within the Linear Matching Method Framework (LMMF). The impact of applied load level and creep dwell on the failure mechanism and location is investigated. Influence of hoop to axial stress ratio and groove angle is studied comprehensively by choosing ranges covering majority of common pipe configurations. Further validation of results is carried out by using detailed step-by-step inelastic analyses in ABAQUS, thereby demonstrating the accuracy and efficiency of LMM eDSCA in predicating the remaining life of multi-material components such as a welded pipe, combining with appropriate creep and fatigue damage models.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129225683","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 Modified Microstructure-Based Creep Damage Model for Considering Prior Low Cycle Fatigue Damage Effects","authors":"Wei Zhang, Xiaowei Wang, J. Gong","doi":"10.1115/PVP2018-84148","DOIUrl":"https://doi.org/10.1115/PVP2018-84148","url":null,"abstract":"A modified continuum damage mechanics (CDM) model was proposed to predict the creep behavior of P92 steel with prior low cycle fatigue (LCF) damage. In order to investigate the damage mechanisms of prior LCF, microstructural observations of P92 steel after various prior LCF and subsequent creep exposures were performed. Results show that the key creep degradation is associated with the martensite lath recovery. Based on the physics of microstructural evolutions, three state variable formulas which represent damage mechanisms related to martensite lath recovery were employed to account for the prior LCF damage. The three state variable formulas which describe the damage evolution with prior LCF cycles were coupled with Hayhurst CDM model. The main advantage of the modified CDM creep model lies in its ability to directly predict creep behavior with different levels of prior LCF damage. The only parameter needed to be known for the prediction is the martensite lath width after prior LCF. Comparison of the predicted and experimental results shows that the proposed model can give a reasonable prediction for creep behavior. Moreover, this model also shows good predictive ability at different strain amplitudes of prior LCF.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"293 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114014536","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":"The Influence of Bauschinger Effect on the Stability of Residual Stresses in Autofrettaged High Pressure Tubes","authors":"H. Maderbacher, M. Pölzl","doi":"10.1115/PVP2018-85123","DOIUrl":"https://doi.org/10.1115/PVP2018-85123","url":null,"abstract":"In the petrochemical industry, in particular for LDPE (Low-Density-Poly-Ethylene) and EVA-processes (Ethylene-Vinyl-Acetate), high strength quenched and tempered steels are used for seamless tubes subjected to ultra-high pressure. The high safety demands at pressures up to 4000bar require besides high fracture toughness and static strength also high fatigue endurance. The fatigue performance can be significantly impoved by the use of autofrettage. In this case residual compressive stresses are generated with simultaneous material work-hardening by targeted plastic deformation in the area of the inner wall of the tube. The positive effect of autofrettage mainly depends on the level of residual compressive stress. The maximum magnitude of these compressive stresses is always smaller than the yield strength of the material in tensile direction, even if the autofrettage level is increased. The amount by what this stress is smaller than the material yield strength depends on the characteristic of the so-called Bauschinger-effect, or on the kinematic hardening behavior of the material.\u0000 The target of the present work is to investigate the stability of residual stresses from autofrettage and their influence on the service life of high pressure tubes under cyclic internal pressure loading. For this purpose, in the first part, the quantitative character of the Bauschinger effect for a high strength quenched and tempered steel is determined by means of specimen tests. In the next step, the influence of the Bauschinger-effect on the resulting residual compressive stresses in a tube-like specimen is investigated. Autofrettage tests are performed on these specimens equipped with strain gages. In the second part of the work, the results of fatigue tests of the mentioned tube-like specimen are compared with the calculated fatigue endurance according to Division 3, Section VIII of the ASME Pressure Vessel Code (BPVC). Calculations are performed, which once use the residual stress correction for reverse yielding according to ASME Code and once consider the actual residual stresses from tests and simulation.","PeriodicalId":275459,"journal":{"name":"Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131730654","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}