bluuebunny/crossref_metadata_2025 huggingface dataset:
Urinary Biomarkers for Sensitive and Specific Detection of Acute Kidney Injury in Humans
Authors: Vaidya Vishal S. , Waikar Sushrut S. , Ferguson Michael A. , Collings Fitz B. , Sunderland Kelsey , Gioules Costas , Bradwin Gary , Matsouaka Roland , Betensky Rebecca A. , Curhan Gary C. , Bonventre Joseph V.
Published: October 2008

Acute kidney injury (AKI) is associated with high morbidity and mortality. The lack of sensitive and specific injury biomarkers has greatly impeded the development of therapeutic strategies to improve outcomes of AKI.

The unique objective of this study was to evaluate the diagnostic performance of nine urinary biomarkers of AKI—kidney injury molecule‐1 (KIM‐1), neutrophil gelatinase associated lipocalin (NGAL), interleukin‐18 (IL‐18), hepatocyte growth factor (HGF), cystatin C (Cys), N‐acetyl‐β‐D‐glucosaminidase (NAG), vascular endothelial growth factor (VEGF), chemokine interferon‐inducible protein 10 (IP‐10; CXCL10), and total protein—in a cross‐sectional comparison of 204 patients with or without AKI.

Median urinary concentrations of each biomarker were significantly higher in patients with AKI than in those without AKI (p < 0.001). The area under the receiver operating characteristics curve (AUC‐ROC) for the combination of biomarkers using a logic regression model [risk score of 2.93*(NGAL > 5.72 and HGF > 0.17) + 2.93*(PROTEIN > 0.22) −2*(KIM < 0.58)] was greater (0.94) than individual biomarker AUC‐ROCs. Age‐adjusted levels of urinary KIM‐1, NAG, HGF, VEGF, and total protein were significantly higher in patients who died or required renal replacement therapy (RRT) when compared to those who survived and did not require RRT.

Our results demonstrate the comparative value of multiple biomarkers in the diagnosis and prognosis of AKI.
Improving the accuracy of breach modelling: why are we not progressing faster?
Authors: Morris Mark , Hanson Greg , Hassan Mohamed
Published: October 2008

Flood risk assessment and management often requires the prediction of potential breaching of a flood defence embankment or dam in order to either assess potential impacts or provide information to assist emergency planning, evacuation, repair strategies and improve alternative future design strategies. There are many different aspects of the overall breaching process, which are more, or less, relevant to the wide range of potential end users of such information. Consequently, the prediction of breach growth is an area where research has been undertaken for many decades in an attempt to provide more reliable models and predictions. However, despite many initiatives providing observations and recommendations as to processes observed and how research might progress, more detailed literature searches will often uncover conclusions and observations noted a decade or two or three earlier that are similar to those being made today. In particular, observations relating to material type, state (such as water content and compaction) and properties are relevant here. This prompts the obvious question as to why our ability to predict breach initiation and growth has not progressed further over this period. Why are so many studies identifying similar issues and, in effect, ‘reinventing the wheel’? With a programme of research into breach initiation and growth under the EC FLOODsite Project and continued pressure to improve tools and techniques following events such as those seen at New Orleans in August 2005, this paper considers this question of apparent slow progress and offers some suggestions as to why this may have occurred and what direction might prove more effective in the future.
Polymerase chain reaction multiplexing of microsatellites and single nucleotide polymorphism markers for quantitative trait loci mapping of wild house mice
Authors: KAWAŁKO AGATA , DUFKOVÁ PETRA , WÓJCIK JAN M. , PIÁLEK JAROSLAV
Published: October 2008

We tested 96 microsatellites and 10 single nucleotide polymorphisms for their allelic distribution in two subspecies of the house mouse, Mus musculus musculus and M. m. domesticus. Sixty‐two microsatellites discriminated strain‐specific differences among nine wild‐derived ‘musculus’ and ‘domesticus’ and three ‘classical’ laboratory strains. For efficient genotyping, we optimized multiplex conditions using five microsatellites per polymerase chain reaction. All 10 single nucleotide polymorphisms were also optimized for simultaneous analysis in one reaction using SNaPshot multiplex. The uniform distribution of markers on autosomes and on the X chromosome makes these panels potentially useful tools for quantitative trait loci mapping of wild house mice.
Direct Assessment (DA) White Paper
Authors: Smith Robert W. , Barrett Zach
Published: October 2008

The U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) has drafted a direct assessment (DA) white paper to summarize the current state of direct assessment activities and practice. Several industry organizations, associations and operating companies have subsequently added content to this white paper improving the accuracy and updating the current state of direct assessment in the pipeline industry. This white paper includes information on DA standards development, drivers, current efforts to further develop DA and an overview of the path forward. Several recent high profile pipeline failures drove the public expectation that pipeline operators understand and improve the integrity of their pipelines. PHMSA has promulgated regulations to require this improved understanding and management of pipeline integrity. During the preparation of the new integrity management requirements, it was recognized that some gas transmission pipelines could not be inspected using then-available assessment techniques, pressure testing and in-line inspection. As a result, PHMSA along with the industry developed and codified several processes for assessing these lines. These processes, which utilized proven tools as part of assessment processes, are collectively called DA.
Dynamic Characteristics Analysis of West-East Pipeline in China
Authors: Wu Yan , Gong Jing , Fan Li
Published: October 2008

This paper, which is based on West-East Gas Transportation Project, manages to build mathematical models to describe hydraulic characteristics and simulate the operation of the system. It studies the impact of changes in hydraulic system, and analyzes the fluctuations in operational characteristics of pipeline combined with initial conditions and boundary conditions, particularly those delivery points that connect different consumers, and investigates operation characteristics and the interaction between laterals, liaison pipelines and the mainline.
Industrial Test and Application of Drag Reducer in Sudan GNPOC Crude Oil Pipeline
Authors: Shui Biyuan , Guan Zhongyuan , Zhao Liying , Shi Xiaoyan
Published: October 2008

The drag reducer, EP-W203, was industrially tested and applied in a long segment of Sudan GNPOC (Greater Nile Petroleum Operating Company) crude oil pipeline. From July 29th to August 3th in 2001, between PS#1 and PS#3, which totals 547km in length, a single point of DRA injection at PS#1 was tested. With an average DRA injection concentration of about 23.4 ppm, 8.28% of drag reduction and 5.09% of throughput increase was gained. It is indicated that 70–80% of drag reduction capacity was still remained after 237 kilometers of pipe wall shear from PS#1 to PS#2. But after severe local shear (without pump shear) during by passing PS#2 process, the DRA almost lost its efficiency. On Dec., 30th, 2001, two points DRA injection test at PS#1 and PS#2 were performed, with injection concentration about 25ppm individually and a total of 12% throughput increase was realized. Since then, routine industrial application of DRA injection at two points were commenced. During the application of DRA since the end of July in 2002, the pipeline throughput suddenly decreased for about 4.32%. Even adding with a third DRA injection point at BV5 was no effect to the pipeline throughput. Research and analysis indicated that due to the change of oil source and the increase of crude viscosity, and the effect of environmental condition in raining season as well, the Reynolds number between PS#2 and PS#3 decreased to lower level, which reduced the function and effect of the Drag Reducer.
Development of Reliability-Based Design and Assessment Standards for Onshore Natural Gas Transmission Pipelines
Authors: Zhou Joe , Rothwell Brian , Nessim Maher , Zhou Wenxing
Published: October 2008

Onshore pipelines have traditionally been designed with a deterministic stress based methodology. The changing operating environment has however imposed many challenges to the pipeline industry, including heightened public awareness of risk, more challenging natural hazards and increased economic competitiveness. To meet the societal expectation of pipeline safety and enhance the competitiveness of the pipeline industry, significant efforts have been spent for the development of reliability-based design and assessment (RBDA) methodology. This paper will briefly review the technology development in the RBDA area and the focus will be on the progresses in the past years in standard development within the American Society of Mechanical Engineers (ASME) and the Canadian Standard Association (CSA) organizations.
Correlation Between Microstructure and Yield Strength in Low-Carbon High-Strength Microalloyed Steels
Authors: Poorhaydari K. , Patchett B. M. , Ivey D. G.
Published: October 2008

Microalloyed pipeline and structural steels are currently graded according to their yield strength. In this work, different microstructural factors that affect the yield strength of the steels are assessed and their contributions to the strength are estimated for several low-carbon microalloyed steels, used in pipeline or structural applications. Emphasis is placed on the relative contribution of grain/sub-grain size, precipitate distribution and dislocation density. Accurate grain/sub-grain size measurements were only possible through electron microscopy imaging. It was found that the increased strength is mainly due to the formation of bainitic structures with fine grain/sub-grain sizes. The contribution from other strengthening sources such as precipitates, dislocations and atoms in solid solution is limited and does not vary much among the several grades examined here. The variation in hardness among the fine-grained heat-affected zone samples (heat input range 0.5–2.5 kJ/mm) of one of the steels was also explained based on the microstructural changes.
Case Study: Mardi Gras Deep Water Transportation System GIS and Underwater Inspections
Authors: McDonald W. Leith , Gin Gordon , Boyle Rachel
Published: October 2008

This paper presents a case study of BP’s Mardi Gras Gulf of Mexico deep water pipeline transportation system. The Mardi Gras Transportation System (MGTS), operated by BP Pipelines, N.A. has set the standard for large diameter, deepwater pipeline design, construction and maintenance. The pipelines range in size from NPS 16 to NPS 30 in water depths up to 7,300 ft. The paper showcases the ArcGIS and PODS relational database management tools and the process of how we implemented programs to track underwater facility features and their displacements caused by the 2005 hurricane season. We will describe the challenges, solutions and new technology used to monitor and maintain the integrity of this pipeline system, even when covered by 5000 feet or more of water. Submarine (ROV) inspection technology, digital video and GPS are the order of the day. We shall demonstrate how GIS can assist in managing and reporting the results of the inspections and setup a database for long term managment of the pipeline system.
The Design, Development and Validation of an Innovative High Strength, Self Monitoring, Composite Pipe Liner for the Restoration of Energy Transmission Pipelines
Authors: Bethel Kyle , Catha Steven C. , Kanninen Melvin F. , Stonesifer Randall B. , Charbonneau Ken , Ekelund Aron , Mandich Ivan , McIntosh Robin , Stringfellow William D.
Published: October 2008

The research described in this paper centers on a composite of thermoplastic materials that can be inserted in a degraded steel pipe to completely restore its strength. Through the use of fabrics consisting of ultra high strength fibers that are co-helically wrapped over a thin walled thermoplastic cylindrical tube that serves as a core, arbitrarily high pressures can be achieved. This paper first outlines the design, manufacturing and installation procedures developed for this unique material to provide a context for the engineering research. Based on this outline, the technological basis that has been developed for assuring the strength and long term durability of this concept during its insertion, and in its very long term service as a liner in energy transmission pipelines, is presented in detail. The research that is described includes burst testing of the material in stand alone pipe form, load/elongation testing of ultra high strength fabrics, and linear and nonlinear elastic and viscoelastic analysis models. This body of work indicates that the concept is fundamentally feasible for restoring a wide range of large diameter natural gas and liquid transmission pipelines to be able to carry arbitrarily high pressures over very long lifetimes. It also indicates that liners can be safely installed in long lengths even in lines with severe bends in a continuous manner. With further research the concept has the potential for eliminating hydro testing and smart pigging during service, and could possibly be installed in some lines that are currently unpiggable.
An Integrated Engineering Model for Prediction of Strain Demands in Pipelines Subject to Frost Heave
Authors: Zhou Joe , Craig Gordon , Hazen Beez , Hart James D.
Published: October 2008

Long distance pipelines are actively pursued by the industry to transport natural gas from remote arctic regions to markets. A chilled gas pipeline is one of the options to minimize the environmental impact resulting from operation of such pipelines. When a chilled gas pipeline crosses discontinuous permafrost areas, differential frost heave can occur. The result is pipe being subjected to potentially high strains, primarily in the axial direction. Reliable prediction of strain demands is one of the key components for a strain-based design process and it is essential for both ensuring pipeline integrity and facilitating life-cycle cost optimization for the design and maintenance of pipelines. The prediction of strain demands resulting from frost heave of chilled gas pipelines involves three fundamental engineering analysis processes. They are gas hydraulic analysis, geothermal analysis and pipeline structural analysis. Not only are these three processes complex, they are also mutually interdependent. To reliably predict strain demands and fully capture the interactions among these processes, TransCanada Pipelines Ltd. (TransCanada) and its partners developed an integrated engineering model on the basis of three well established programs for the three individual engineering processes. This paper will briefly review the integrated model for strain demand prediction.
Application of High-Grade Steels to Onshore Natural Gas Pipelines Using Reliability-Based Design Method
Authors: Zhou Joe , Rothwell Brian , Zhou Wenxing , Nessim Maher
Published: October 2008

Two example onshore gas pipelines were designed using a reliability-based approach. The first example (1219 mm, 17.2 MPa) represents a high-pressure large-diameter pipeline; the second example has a smaller diameter (762 mm) and lower pressure (9.9 MPa). Three steel grades (X70, X80 and X100) were used to develop three design solutions for each example. The wall thickness-related life cycle costs of the designs were evaluated. The design outcomes show that the reliability targets for both examples can be met using X100 steels and high equivalent design factors (0.93 for the first example and 0.9 for the second example). Moreover, ruptures and excessive plastic deformation of a defect free pipe were found to be insignificant integrity threats even when the design uses X100 and relatively high equivalent design factors such as 0.85 and 0.9. The economic assessment results show that the X100 design is the most economical option for the high-pressure large-diameter example. However, using X100 does not show a clear economic advantage over using X80 for the second example mainly because the wall thickness for the design using X100 is governed by the maximum D/t ratio constraint. The study also demonstrates the advantages of the reliability-based approach as a valuable tool in assessing the feasibility and potential benefits of using high-grade steels on a pipeline project.
Remote and Intelligent Diagnostic Methods on Leakage Fault for Crude Oil Pipelines
Authors: Zhang Lai-Bin , Wang Zhao-Hui , Liang Wei
Published: October 2008

Oil and gas transportation pipelines are the key equipment in petroleum and chemical industry. At present, with the increase of transportation task in oil fields, real-time leak detection system becomes a demand that petroleum companies need to safeguard routines. At the heart of the leakage monitoring and detection procedures are the report of leakage event timely and of leakage point precisely. This paper presents a more realistic approach for using rarefaction-pressure wave technique in oil pipelines, which aims to two targets, one is the improvement of remote and intelligent degree, and the other is the improvement of the leakage location ability. This paper introduces a new scheme to meet the requirements of real time and high data transferring necessary for remote monitoring and leak detection methods for pipelines. The scheme is based on SCADA framework for remote pipeline leakage diagnosis, in which the Dynamic Data Exchange technology is utilized to construct the data-acquiring component to acquire the real-time information that could perform remote test and analysis. It also introduces a basic concept and structure of the remote leak detection system. Primarily, an embedded leak-detection package is designed to exchange the diagnostic information with the RTU data package of Modbus protocol, and then via fiber network, the SCADA-based remote monitoring and leak detection system is realized. Existing data acquisition apparatus applied in oil fields and city underground water pipeline is used, without changing the structure of pipeline supervisory system. This paper introduces the method of constructing DDE-based hot links between servers and client terminals, using Borland C++ Builder 6.0 development environment, and also explains the universality and friendliness of the method. It can easily access similar Windows’ applications simply by modifying Service names, Topic options and data Items. System feasibility was tested using negative-pressure data from oil-fields. Additionally, the applied results show that the whole running status of pipeline can be monitored effectively, and a higher automation grade and an excellent leak location precision of the system can be obtained.
Detection of the Propagation of Defects in Pressurized Pipes Through the Acoustic Emission Technique Using Artificial Neural Networks
Authors: Soares Sergio Damasceno , da Silva Romeu Ricardo
Published: October 2008

The acoustic emission test has distinguished relevance in non-destructive testing and, therefore, existing research abound at present aiming at the improvement of the reliability of their results. In this work, the methodologies and the results obtained in a study performed are presented to implement pattern classifiers by using artificial neural networks, aiming at the propagation of existing defects in pressurized pipes by means of Acoustic Emission testing (AE). Parameters that are characteristic of AE signals were used as input data for the classifiers. Several tests were performed and the classification performances were in the range of 92% for most of the instances analyzed. Studies of parameter relevance were also performed and showed that only a few of the parameters are actually important for the separation of classes of signals corresponding to No Propagation (NP) of defects and Propagation (P) of defects. The results obtained are pioneering in this type of research and encouraged the present publication.
Near-Neutral pH SCC of Two Line Pipe Steels Under Quasi-Static Stressing Conditions
Authors: Zheng W. , Bibby D. , Li J. , Bowker J. T. , Gianetto J. A. , Revie R. W. , Williams G.
Published: October 2008

Most published SCC results for the near-neutral pH condition were produced under cyclic loading. However, the presence of stress corrosion cracks in pipeline systems involving very small pressure fluctuations suggests the cracking should initiate and grow without large dynamic loads. This study was designed to investigate this issue. A Grade 448 (X-65) line pipe steel and a prototype Grade 550 (X-80) steel were evaluated in near-neutral pH solutions. The maximum stress applied was at 95% of the respective yield strengths and the R values applied were between 0.98 and 1.0. Two solutions were used for each steel: NS4 and NS4/clay mixture. The solutions were purged with a gas mixture of 95%N2 and 5%CO2. Recognizing that the crack propagation rate can be very slow under such near-static conditions, relatively long-term tests were carried out. The durations of the three tests using the prototype Grade 550 (X-80) steel were 110 days, 54 days and 26 days, and the duration for the X-65 steel was 110 days. After 110 days, the majority of the cracks in the Grade 550 (X-80) steel were in the range of 5 to 30 micrometers (μm) deep, giving an average crack propagation rate of 2*10−9 mm/s. Tests at short durations revealed that only a few cracks were detectable after 26 days and that several more cracks were produced after 54 days. So majority of the cracks in the 110-day were likely produced after 54 days of testing. The NS4/clay mixture was found to be less aggressive than the NS4 solution for both steels studied. The cracks in the prototype Grade 550 (X-80) steel were deeper and more numerous in comparison with the X-65 steel. Possible reasons for this observation are also explored in terms of the presence of martensite-austenite (MA) phase in the Grade 550 (X-80) steel.
Calculation of Strains in Dents Based on High Resolution In-Line Caliper Survey
Authors: Lukasiewicz Stanislaw A. , Czyz Jaroslaw A. , Sun Chao , Adeeb Samer
Published: October 2008

The strain level in a deformed pipe wall has been included in recent years in the assessment of severity of dents in order to better prioritize and effectively repair mechanical damage in pipelines. High resolution caliper data provide accurate dent shape that can be used for determination of strains using commercial Finite Element Method (FEM) programs. However, those programs, designed to solve a variety of general problems, are very inefficient in calculation of strains in a pipewall with known radial displacements. This paper presents a very efficient method that combines analytical techniques with FEM approach. After properly filtering the caliper measurements the bending strain is calculated from the pipewall curvature, and the membrane strain is obtained using a FEM shell model that includes nodes with only two degrees of freedom in the mid-plane of the wall.
A Case Study of Gas Leakage and Assessment of Mechanical Properties With Welding Variables in Fillet Weldment of Small Diameter Pipe
Authors: Baek Jong-Hyun , Kim Woo-Sik
Published: October 2008

A branched pipe joint has been employed to execute the pressure control, condition check, purgation, and distribution of the gas in the natural gas facilities. Installation of branch pipes is generally done through the welding work, and as a welding process, the weldolet and the sockolet are used. During the maintenance working of in-service natural gas pipeline, there was gas leakage in sockolet weldment. The causes of incident were investigated with various tests. We found the wrong pipe material, the weld defect and the non-destructive test limitation of fillet weldment as the reasons of gas leakage. As the follow-up measures, it was done to assess the soundness depending upon the configuration of the weld zone, a change in the welding process and a change in the pipe diameter by assessing the mechanical properties of the sockolet weld zone and further to assess comparatively the mechanical performance of the sockolet weld zone and that of the weldolet weld zone. In the sockolet weld, the tensile strength showed no difference and the fatigue strength showed a difference depending upon a change in the welding process. In the case that the leg length of the weld zone was made lengthwise in the direction of the branch pipe, the SMAW welding work compare with the GTAW, the sectional area of the weld zone was more increased, and the pipe diameter was more increased, the fatigue strength was increased.
Influence of Internal Pressure for Depth Measurement on a Dent
Authors: Le Bastard Avigae¨le
Published: October 2008

The main cause of failure for most transmission pipelines is third party damages, which conduct to the creation of dents. Depending on their dimensions, these defects can be detrimental in term of pipeline integrity. Defect measurement is usually performed on field when the pipeline is under pressure. However, common assessment criteria are based on the defect characteristics measured in absence of internal pressure. An empirical relation — Ho = 1.43 Hr — links the dent’s depth in absence of pressure Ho to its depth under pressure Hr. It can be assumed that the dent’s depth decreases as internal pressure increases; however, the relation is used whatever the pressure value, during measurement, is. Therefore, this relation can be considered as too conservative, and not realistic, especially when the pressure during defect characterization is low. This study presents a new relation linking Ho and Hr based on results of finite elements calculations and experimental data. The calculated results are always conservative, and the difference between experimental and calculated data does not exceed one percent. Gaz de France Research and Development division has also been able to decrease the coefficient of the relation below 1.43 for most of cases, especially for low values of internal pressure. But some cases with a coefficient between Hr and Ho which overtook 1,43 were also found. The depth of a dent without pressure can then be determined by taking into account the internal pressure when measuring the size of the dent.
Nano Precipitate Analysis of X80 Pipeline Steel Using Small Angle Neutron Scattering
Authors: Wiskel J. B. , Ivey D. G. , Henein H.
Published: October 2008

An understanding of precipitate size distribution and its evolution with processing conditions is important with regards to the final mechanical properties of microalloyed pipeline steel. A study was undertaken using small angle neutron scattering (SANS) to quantify the size distribution of nano-sized precipitates in X80 pipeline steel. The distributions obtained for different X80 samples were correlated with the finish rolling temperature and final coiling temperature as a means of identifying processing conditions that may enhance fine precipitate evolution. The precipitate distribution predicted for Grade 100 steel using SANS data is compared to data obtained from a TEM particle counting analysis.
Field Trial of the NoPig Inspection System
Authors: Choudhary Usman K. , Lee Rachel , Worthingham Robert
Published: October 2008

The NoPig system is an above ground metal-loss detection tool utilizing magnetics. Sensors at ground level detect disturbances in the magnetic field around the pipeline generated by impressed alternating current (AC) signals. This tool is intended for use on segments of pipeline which are considered unpiggable. Previous field trials indicated the tool was capable of detecting metal-loss in small diameter seamless pipe. Trials on electric resistance weld (ERW) or double submerged arc weld (DSAW) pipe were inconclusive. Modifications have been made to the NoPig hardware and analysis software to correct for the non-uniform magnetic fields produced by seamed pipe and girth welds. The study reported in this paper is a field trial of the modified inspection system. Recently inline inspected pipelines of nominal pipe size (NPS) 12 and 16 were selected for survey. Pipeline segments where significant metal-loss was detected from Inline Inspection (ILI) were selected for the blind test. Eight hundred meter sections of pipeline were surveyed at each of these locations to ensure a range of pipe conditions were included. After all surveys were complete, significant features were excavated and actual measurements were obtained. This paper describes the field inspection program as well as the analysis process used to verify the detection capabilities of the modified NoPig system. The results will include discussion of the positional accuracy, detection capability and threshold of the system. This analysis will help determine if the NoPig system is suitable alternative for assessing the integrity of unpiggable pipeline segments.
A New Role on the Pipeline EPCM Project
Authors: Parker David
Published: October 2008

Recent developments in the application of spatial information technologies have brought opportunities for dramatic improvements in speed, accuracy and cost-effectiveness of production of pipeline project deliverables. In addition to the potential for design and construction improvements, life cycle improvements are found through the use of spatial data relating to pipeline operation, environmental stewardship, regulatory, public and other stakeholder communications. However, these opportunities have not been consistently captured on all pipeline jobs. Part of the challenge in the introduction of new technology is to align members of the team so that skills and assigned tasks are matched. Traditionally, pipeline design and construction projects have employed a proven team organization structure. Changes to the tradition are necessary. This paper discusses the main advantages of using spatial information on a pipeline project. Furthermore, a discussion of the various project team roles explores how to leverage the new technologies effectively. Examples drawn from the largest pipeline projects currently in process will highlight the lessons learned to date.
PipeRep Software: A Decision Support Tool for the Repair of Pipelines
Authors: Chateau Emmanuel , Hertz-Cle´mens Ste´phane , Barre Cle´o
Published: October 2008

A common problem for pipeline operators is the choice of the most suitable repair technique for a given defect found on an operating pipeline. Several permanent repair techniques may be available. However, each repair method is characterized by its specific application range, and the choice of the most suitable ones is not always intuitive. In order to support decision made by operational teams confronted with such an alternative, Gaz de France R&D Division has developed an integrated software, PipeRep, aimed to provide an immediate answer. Through the input of pipeline and defect characteristics, the reparability of the defect is assessed, and the software indicates which techniques are suitable or not for the planned repair. In addition, a distinction is made during the assessment of the repair between burst and fatigue strength, the software indicating whether a repair can be considered as permanent, or temporary. The PipeRep software provides an efficient support for the choice of the most suitable repair technique, and is periodically updated regarding repair procedures adaptation and repair techniques technical progress.
A Time Dependent Model for Assessing the Significance of Mechanical Damage
Authors: Martin Michael , Andrews Robert (Bob)
Published: October 2008

A small but significant number of pipeline failures occur each year and many in populated regions arise as a result of mechanical damage from external interference. These failures generally occur at the time of damage, but a small number are delayed, with the final failure reportedly taking place following periods of up to 40 years from the original damage. This type of failure is of concern to pipeline operators as they occur without warning. The mechanisms governing time-delayed failures are poorly understood due to the extremely limited experimental data available. A greater understanding of the failure mechanism would help operators to improve their strategies for managing external interference damage. In the event of combined dent and gouge mechanical damage, the model described in this paper provides an approach for the assessment of the time dependent failure modes of the defective pipeline. The model, developed using Matlab code, is capable of investigating a complex load history consisting of constant internal pressure hold periods and cyclic fluctuations and can predict time dependent phenomenon such as pressure reversals sometimes experienced following hydrostatic pressure testing. The approach is based on the BS 7910 material specific Failure Assessment Diagram (FAD) in conjunction with R5 (British Energy) creep procedures. The result is a time dependent FAD which allows the combined influence of time dependent material properties (toughness, strength and cold creep) and loading to be investigated.
Deepwater Pipelines: Reliability of Finite Element Models in the Prediction of Collapse and Collapse Propagation Loads
Authors: Toscano Rita G. , Dvorkin Eduardo N.
Published: October 2008

In the design of pipelines it is of utmost importance to use validated numerical tools, usually finite element models, to reliably determine the structural limit loads. Also for steel pipes manufacturers it is very important, for establishing the set-up of their production processes, to be able to analyze using validated finite element models the effect that different manufacturing imperfections have on the pipe limit loads (e.g. “ovalization” of the external diameter, eccentricity, residual stresses, etc.). For deepwater pipelines the most relevant limit states that need to be analyzed are the collapse and collapse propagation under different combinations of external pressure and bending. In the second section of this paper we discuss the finite element models that we developed to predict the collapse and collapse propagation of seamless steel pipes under external pressure and bending. The validation of these models was performed comparing the numerical results with experimental results obtained at CFER (Edmonton, Canada) [1] and at our lab for the pre-collapse and post-collapse regimes. In deepwater pipelines, in order to prevent the propagation of collapse failures through the pipeline length, buckle arrestors are used. In the third section of this paper we review the finite element models that we developed to predict buckle arrestors cross-over external pressures. The validation of these models was performed comparing the numerical results with experimental ones obtained at our lab for different ratios [arrestor thickness/pipe thickness] corresponding to either the flattening or flipping cross-over mechanisms [2]. Finally in the fourth section of this paper the validated finite element models are used to perform parametric analyses that provide useful data for pipeline engineers on the effect of different geometrical parameters on crossover pressure.
Inline Inspection of Dents and Corrosion Using “High Quality” Multi-Purpose Smart-Pig Inspection Data
Authors: Paeper Steffen , Brown Bryce , Beuker Thomas
Published: October 2008

A new generation of geometry sensor for ILI tools has been developed. This sensor provides highly accurate geometry data of the internal pipe contour. The technology uses the benefits of a touchless distance measurement in combination with the advantages of a mechanical caliper arm. The complementary interaction allow the measurement of accurate data under demanding operational conditions. The geometry sensor technology can be combined with a navigation unit and the high resolution MFL inspection technology on so called multi-purpose ILI-tools. The merging of different inspection tasks on a single tool is an economic solution to create and add to an ILI-database for integrity management. Field experience with this new technology will be discussed, based on more than 500 miles inspected pipeline. Most inspections were performed in the US and Canada. The operational performance of the sensors justified the new design.
Estimation Procedures for J and CTOD Fracture Parameters Using Three-Point Bend Specimens
Authors: Donato Gustavo H. B. , Ruggieri Claudio
Published: October 2008

This work presents the development of J and CTOD estimation procedures for deep and shallow cracked bend specimens based upon plastic eta factors and rotational factors. The techniques considered include: i) estimating J and CTOD from plastic work and ii) estimating CTOD from the plastic rotational factor. The primary objective is to derive estimation techniques which are applicable to determine J and CTOD fracture parameters for a wide range of a/W-ratios and material flow properties. Very detailed non-linear finite element analyses for plane-strain models provide the evolution of load with increased load-line displacement and crack mouth opening displacement which are required for the estimation procedure. Laboratory testing of a structural steel using shallow and deep crack bend specimens provide the data needed to determine the CTOD-values for the material based upon the proposed methodology. These fracture toughness values are compared against the results obtained based upon the estimation equations given by BS 7448. The present analyses, when taken together with previous studies, provide a fairly extensive body of results which serve to determine parameters J and CTOD using bend specimens with varying geometries.
Mitigation of Frost Heave of Chilled Gas Pipelines Using Temperature Cycling
Authors: Morgan Vincent , Hawlader Bipul , Zhou Joe
Published: October 2008

A number of recent studies have been undertaken by the pipeline industry to improve understanding and design capability of frost heave issues related to the operation of large diameter chilled gas transmission pipelines through areas of discontinuous permafrost. These studies have included the assessment of methods of reducing the effects of frost heave on pipeline integrity, in particular the onset of significant bending strain due to differential vertical displacement of the pipeline. This paper will present one component of a study to investigate and assess the use of temperature cycling of the product as a means of reducing long-term frost heave of a pipeline system. The use of chillers at compressor station locations is considered a feasible method of controlling the gas temperature in the pipeline. The studies were undertaken using a geotechnical centrifuge as a cost effective means of obtaining physical test data under realistic soil stress conditions. The potential benefits of cyclic temperature operation in reducing pipeline strain are discussed.
Investigating the Effect of UOE Forming Process on the Buckling of Line Pipes Using Finite Element Modeling
Authors: Adeeb Samer , Zhou Joe , Horsley Dave
Published: October 2008

Buried line pipe are often subjected to compressive and/or bending loads at locations of ground movements. Those loads might increase the strain of the pipe at some location beyond a critical value and thus a buckle is formed on the pipe wall. Finite element modeling is an excellent numerical technique that can predict the values of the critical strains that a pipe can withstand before buckling. However, these numerical models require an accurate representation of the spatial material behaviour. Tensile specimens taken from the longitudinal and the transverse directions of a line pipe formed using the UOE process often exhibit different behaviour. Finite Element Models of buckling of line pipe often use the tensile properties exhibited by longitudinal specimens without taking into consideration the effect of the different behaviour in the transverse direction. In order to investigate the effect of the forming process a finite element model of forming a plate into a pipe was analyzed. The model was analyzed twice, once with isotropic hardening material properties and the other with kinematic hardening material properties with a constant size for the yield surface. The behaviour under tensile loading of the formed pipe in both the longitudinal direction and the transverse direction were quite different between the two models. The results show that the kinematic hardening material model can predict the difference in the tensile properties often seen between specimens taken from the longitudinal versus the transverse direction of the pipe. The material model is extended further to model the buckling of line pipe. The results show that the buckling of line pipes is dependent on the behaviour of the pipe in both the longitudinal and the transverse direction.
Establishing a Safe Working Pressure During Excavation of a Pipeline in a Rock Ditch
Authors: Adeeb Samer , Horsley David , Zhou Joe , Sadoway Brad
Published: October 2008

In order to perform pipeline maintenance it is often necessary to excavate the pipeline. To ensure this is conducted safely, the expected condition of the pipeline and possible failure scenarios are considered in order to establish a safe operating pressure during the excavation and subsequent work. For pipelines that are laid in rocky terrain, consideration must be given to the possibility of a large rock impacting the pipeline. The purpose of this work is to describe the application of a numerical procedure to establish the safe working pressure during the excavation of a pipeline in a rocky terrain. A numerical procedure, developed previously [1] was shown to conservatively estimate a safe working pressure for the case of a rock falling on the pipeline. FEA was used to determine the relationship between the available kinetic energy of a falling rock and the energy to puncture the pipeline (as a function of internal pressure). The resulting puncture dimensions were then compared to the critical-crack-length to cause rupture. The safe pressure was obtained from the pressure where rupture first occurs, reduced by an appropriate safety factor. This paper describes the application of the numerical procedure described to cover a large range of pipe toughnesses and internal pressures.
Gas-Breakout of the West-East Pipeline and Its Control Research
Authors: Jiang Duzhi , Gong Jing , Li Bo
Published: October 2008

In order to know roundly the run circumstances of the gas pipeline system under different conditions, predict the impact of diversified factors and the adaptability of the gas pipeline to the customer requirements, this paper makes hydraulic analyses for three kinds of gas-breakout accidents that happen possibly in the west-east pipeline, and constitutes the corresponding control methods. Through the analyses, we can understand syllabify the influencing degree and process that the short-term accidents caused by different sections impose on the pipeline’s natural run. These analytical results will have directive effects on compiling the compilation schemes to rush to repair the pipeline, deciding the scheme of gas storage construction and keeping the pipeline running safely.
A Common Mathematic Model for Solving Hot Oil Pipeline Transient Heat Transfer and Flow Problems and Its Application
Authors: Cui Xiuguo , Zhao Liying
Published: October 2008

A mathematic model to describe transient heat transfer and flow problems during pipelining hot crude oil is established. The model can be used to solve typical transient heat transfer and flow problems of hot oil pipelines, such as the change of throughput rate and heated temperature of oil, shut-down and restarting of pipeline, and preheating newly-built pipeline. For the transient heat transfer problem brought by changing oil heated temperature, the calculation result of the common model developed in the paper is between calculation result of Russian analytical formula and Russian measurement results. As another example, the thermal process of preheating Dong-Bin pipeline is calculated, the comparison between field measurement results and calculation results shows that the common model developed in the paper can meet the demand of thermal calculation of field pipeline.
Study on the Mismatched Girth Welds of X80 Line Pipes
Authors: Zhuang Chuanjing , Feng Yaorong , Huo Chunyong
Published: October 2008

X80 linepipes are going to be widely used for gas transmission pipelines in China. The welding procedure for girth weld is very critical to the safety of the X80 pipeline. In this paper, different welding procedures are employed to obtain three different mismatched girth welds, with which tests were carried out to analyze effect of mismatch on the properties of girth welds. Plastic deformation and critical defect size (δc) is calculated and discussed for the different mismatched girth welds utilizing both FAD and FEM methods. Overmatched or evenmatched girth weld is recommended for high grade linepipes because overmatched weld has the advantages of improving limit load and enhencing fracture resistance of pipe girth welds. But the increase of weld strength may reduce the resistance of the weld to HIC and SCC, as well as make the field weld operation more difficult. The level of mismatch shouldn’t be too high because too much weld seam strength will not only be a way of waste, but also decrease weld resistance to HIC cracks.
Study on the Assets Integrity Management System of Long Distance Oil and Gas Pipeline
Authors: Wang Weibin , Tong Wenqiang , Yang Zupei , Ai Muyang , Cui Hongsheng , Zhao Liying , Zhang Huifen , Zhou Lijian
Published: October 2008

The integrity management system of steel pipeline is an international popular pattern of assets management at present. It has important meaning and effect that establishing and consummating a set of assets integrity management (AIM) system with practical application value in all the integrity management system. By using the AIM system, risk can be identified and ranged timely; more detect and assess data may be gained; the maintenance and remedy cost can be saved and the monitoring become more convenient and quick. Thereby, the AIM system can contribute to dynamic and circular integrity management. According to the latest research development of integrity management in the international, this paper illustrate the assets integrity management in detail from the aspect of the application of assets integrity management, design way, workflow, and function introducing, which is based on the design module of assets integrity management.
Leak Detection in a Pipeline Using Modified Line Volume Balance and Sequential Probability Tests
Authors: Di Blasi Marti´n , Muravchik Carlos
Published: October 2008

The use of statistical tools to improve the decision aspect of leak detection is becoming a common practice in the area of computer pipeline monitoring. Among these tools, the sequential probability ratio test is one of the most named techniques used by commercial leak detection systems [1]. This decision mechanism is based on the comparison of the estimated probabilities of leak or no leak observed from the pipeline data. This paper proposes a leak detection system that uses a simplified statistical model for the pipeline operation, allowing a simple implementation in the pipeline control system [2]. Applying linear regression to volume balance and average pipeline pressure signals, a statistically corrected volume balance signal with reduced variance is introduced. Its expected value is zero during normal operation whereas it equals the leak flow under a leak condition. Based on the corrected volume balance, differently configured sequential probability ratio tests (SPRT) to extend the dynamic range of detectable leak flow are presented. Simplified mathematical expressions are obtained for several system performance indices, such as spilled volume until detection, time to leak detection, minimum leak flow detected, etc. Theoretical results are compared with leak simulations on a real oil pipeline. A description of the system tested over a 500 km oil pipeline is included, showing some real data results.