bluuebunny/crossref_metadata_2025 huggingface dataset:
YM155 induces apoptosis through downregulation of specificity protein 1 and myeloid cell leukemia‐1 in human oral cancer cell lines
Authors: Sachita Khadka , Yu Hyun‐Ju , Yun Jun‐Won , Lee Jeong‐Sang , Cho Sung‐Dae
Published: December 2014

Background

YM155 is a small‐molecule pro‐apoptotic agent which has shown to inhibit survivin expression and induce apoptosis in various cancer cells. In this study, we investigated the function and molecular mechanism of YM155 in human oral cancer cells.

Methods

The apoptotic effects and related signaling pathways of YM155 were evaluated using trypan blue exclusion assay, 4′‐6‐diamidino‐2‐phenylindole staining, Western blotting, RT‐PCR, and siRNA.

Results

YM155 inhibited the growth and caused caspase‐dependent apoptosis in MC3 and HN22 cells. YM155 significantly suppressed the level of survivin protein expression through proteasome‐dependent protein degradation to confirm its survivin‐inhibiting function. YM155 reduced myeloid cell leukemia‐1 (Mcl‐1) protein, but it did not alter Mcl‐1 mRNA. It was associated with the facilitation of lysosome‐dependent protein degradation. The modifications of Mcl‐1 and survivin by YM155 were caspase‐independent manner. Treatment of MC‐3 and HN22 cells with YM155 inhibited specificity protein 1 (Sp1) and the knockdown of Sp1 by siRNA demonstrated that Mcl‐1 was regulated by Sp1 protein.

Conclusions

We demonstrated the novel mechanism that YM155 causes apoptosis of human oral cancer cell lines through downregulation of Sp1 and Mcl‐1. Therefore, it may be a potential anticancer drug candidate for the treatment of oral cancer.
Growth performance and physiological parameters of conventional and specified pathogen‐free rats fed autoclaved diets with different protein sources
Authors: Barszcz M. , Paradziej‐Łukowicz J. , Taciak M. , Tuśnio A. , Staśkiewicz Ł. , Muszyńska‐Furas B. , Lewandowska A. , Pastuszewska B. , Skomiał J.
Published: December 2014

The effects of feeding autoclaved commercialSSNIFF(SN) diet and diets containing soya bean (S) and casein (C) to growing conventional (CON) and specified pathogen‐free (SPF) rats were determined. Diets S, C andSN, autoclaved at 121 °C during 20 min (T1), at 134 °C during 10 min (T2) and non‐autoclaved (T0), were fed during four weeks, each to 8CONmales and 8 females of mean initial body weight 56 g, kept individually. Diets S, C andSN, autoclaved at T1, were fed during two months, each to 20 SPF males and 20 females of mean initial body weight 58 g, kept in group of 5 animals per cage. InCONrats, autoclaving did not affect feed intake and weight gain, decreased thyroid and stomach weight, increased caecal tissue and digesta weight, and concentrations of isobutyric, isovaleric and valeric acid in caecal digesta. Among biochemical blood parameters, autoclaving decreased only total protein concentration and aspartate aminotransferase activity. Feeding C diet resulted in lower feed intake and weight gain inCONandSPFmales. Diet affected organ weights and the greatest differences were found in rats onSNdiet for weights of stomach, caecum and female reproductive organs. Diet affected concentration of all short‐chain fatty acids, pH and weight of caecal digesta, the most important being the greatest butyric acid concentration onSNdiet and isoacids on C diet. It is concluded that autoclaving of both soya‐containing and soya‐free diets does not affect negatively animal performance and physiology.
DNA markers for eating quality of indica rice in Indonesia
Authors: Lestari Puji , Jiang Wenzhu , Chu Sang‐Ho , Reflinur   , Sutrisno   , Kusbiantoro Bram , Kim Backki , Piao Rihua , Cho Young‐Chan , Luo Zhixiang , Chin Joong‐Hyeon , Koh Hee‐Jong
Published: December 2014

Rice eating quality is considered to be one of the top priorities in determining the agronomical value of rice; thus, the rapid evaluation of eating quality at early breeding generations in breeding programmes for better eating quality is of great importance. In an attempt to develop DNA markers associated with eating quality of indica rice, we used multiple regression analysis to test 54 markers, which were preselected for their possible association with eating quality, using 24 indica varieties with different palatability scores. Of these markers, eighteen markers were found to be significantly associated with palatability according to sensory evaluation. Accordingly, a marker set in the model regression equation with a high R2 (0.997) was formulated to estimate indica rice palatability. Validation suggests that markers and the statistical parameters formulated by the equation could be a potential tool to predict the palatability of cooked Indonesian indica rice and could be reliable in developing country‐dependent model equations for eating quality.
Global Justice and Charity: A Brief for a New Approach to Empirical Philosophy
Authors: Hassoun Nicole
Published: December 2014

What does global justice or charity requires us to give to other people? There is a large theoretical literature on this question. There is much less experimental work in political philosophy relevant to answering it. Perhaps for this reason, this literature has yet to have any major impact on theoretical discussions of global justice or charity. There is, however, some experimental research in behavioral economics that has helped to shape the field and a few relevant studies by political philosophers. This paper reviews this research. Moreover, it argues that the little work that has been done can offer some methodological lessons to empirically engaged philosophers of many kinds. Finally, it suggests that there is reason for those interested in global ethics and charitable giving to consider doing new kinds of experimental and other empirical work in addition to traditional experimental philosophy.
Probability and Logic
Authors: Easwaran Kenny
Published: December 2014

Probability and logic are two branches of mathematics that have important philosophical applications. This article discusses several areas of intersection between them. Several involve the role for probability in giving semantics for logic or the role of logic in governing assignments of probability. Some involve probability over non‐classical logic or self‐referential sentences.
The Affect Misattribution Procedure: Ten Years of Evidence on Reliability, Validity, and Mechanisms
Authors: Payne Keith , Lundberg Kristjen
Published: December 2014

The affect misattribution procedure (AMP) measures automatically activated responses based on the misattributions people make about the sources of their affect or cognitions. The AMP is one of the most widely used implicit attitude measures, and evidence regarding its reliability and validity has grown rapidly. In this brief review, we survey the evidence of reliability and validity while discussing the mechanisms that drive priming effects in the AMP. We consider the unique capabilities of this procedure to measure implicit and explicit cognition with simplicity and greater experimental control than other measures. Finally, we offer recommendations for using the AMP effectively for a wide variety of research purposes.
Experimental Investigation of Wax Deposition at Different Deposit Locations Through a Detachable Flow Loop Apparatus
Authors: Li Si , Huang Qiyu , Wang Wenda , Wang Changhui , Ding Zhenjun
Published: December 2014

Wax deposition has always been a focus in the research field of flow assurance. Operating conditions are among the predominant factors that control the deposition rate and the nature of the formed deposits. However, the disadvantages of the available wax thickness measurement techniques applied to laboratory flow loops limit deeper studies on this issue. In this work, the effects of operating conditions, including temperature interval and flow rate, on wax deposition at different deposit locations are experimentally studied using a detachable flow loop apparatus. With the detachable test section, it is achievable to obtain the thickness and the wax content profiles of the deposit as functions of axial location and time. The temperature fields in the test section under both temperature intervals are simulated with CFD software FLUENT to provide more information for the analysis of deposition process. As the results manifest, the low temperature interval tends to intensify deposition, relating to the inner temperature field and wax precipitated property of the oil. The larger flow rate leads to a growth in the deposit thickness under the laminar flow regime and brings about a distinct rise in the wax content of deposit at inlet. In addition, the increase in deposit thickness and wax content indicates the phenomenon of deposit aging, and the wax deposit layer is thinner but with higher wax content at the inlet, due to the strong flow scour.
Comparison of Degradation of Two Different Gas Turbine Engines in Natural Gas Compressor Stations
Authors: Hartloper C. , Botros K. K. , Golshan H. , Rogers D. , Samoylove Z.
Published: December 2014

Gas Turbine (GT), like other prime movers, undergoes wear and tear over time which results in performance drop as far as available power and efficiency are concerned. In addition to routine wear and tear, the engine also undergoes corrosion, fouling etc. due to the impurities it breathes in. It is standard procedure to ‘wash’ the engine from time to time to revive it. However, it is important to establish a correct schedule for the wash to ensure optimal maintenance procedure. This calls for accurate prediction of the performance degradation of the engine over time. In this paper, an error-in-variables based methodology is applied to evaluate the performance degradation of two GT engines between soak washes. These engines are LM2500+ (single spool) and RB211-24G (twin spool). The engine-air-compressor isentropic efficiency and air inlet flow rate as well as the engine heat rate and specific work are analyzed for both engines. For both engines, the compressor isentropic efficiency is found to degrade over time, while the engine heat rate correspondingly increases. The compressor air inlet flow rate and engine specific work remain mostly constant. Through a comparison between the time-history of the engine health parameters, it is found that the LM2500+ degrades at a much faster rate than the RB211-24G. However, the degradation of the LM2500+ is found to be fully recoverable by offline washes, while the degradation of the RB211-24G is only slightly recovered by offline washes. The RB211-24G engine is found to be running near its maximum efficiency at all times, which is likely the cause for the observed non-recoverable degradation that the engine experiences. The engine’s site location is also found to contribute to the degradation that the engine experiences.
Models and Methods of Determining the Minimum Stack Metal Temperature During Sonic Blowdown of Natural Gas
Authors: Hartloper C. , Botros K. K. , Abdalgawad E. , Reid S.
Published: December 2014

During a natural gas blowdown event, the flow through the blowdown stack is either sonic or supersonic at the stack exit. In this case, the temperature of the gas at the stack exit can drop significantly as the gas enthalpy is converted to kinetic energy. Depending on the initial pipeline temperature, it is possible for the gas temperature at the stack exit to drop below the minimum metal temperature specification of the stack steel grade. Traditionally in this case it is assumed that the blowdown-stack metal temperature follows the gas temperature; therefore, it would also drop below this minimum temperature. However, analogous to the decrease in the temperature of the gas as the velocity increases, the gas will increase in temperature as the velocity decreases near the wall of the stack due to the boundary layer. As such, the blowdown-stack wall temperature will not decrease to the same extent as the bulk gas temperature during the blowdown event. This phenomenon is referred to as wall temperature recovery. This paper describes the various models and methods for determining the extent of this temperature recovery via a parameter known as “recovery factor” which is a function of the flow Reynolds number, Prandtl number, Mach number, etc. These methods are evaluated and compared for several pipeline conditions, and the most suitable model is determined. It is recommended that fundamental blowdown testing on natural gas be conducted on well instrumented full-bore blowdown stack to validate the predictions by these methods.
Forecasting the Consequences of Pipeline Failures
Authors: Cunha Sérgio B.
Published: December 2014

The consequences of the accidental release of petroleum based liquids or natural gas from onshore pipelines are studied. Damage to property, environment and society are considered. Property damage and environmental reparation costs are evaluated directly from publicly available data. Straight forward regression models are proposed to quantify these types of consequence, considering the released fluid and the characteristics of the environment. Societal impact, taken as the number of casualties, is evaluated by combining approximated fire models, heat vs. mortality correlations, population density and the statistical value of life. For gas, a jet fire model is employed; the heat flux is parameterized by the pressure and the failure size. For liquid releases, either pool or jet fire model might be employed, according to the size of the hole. The heat flux of the pool fire model depends on the size of the pool, which is determined by a correlation between released volume and affected area. On the jet fire model the heat flux is parameterized by the release rate and the heat of combustion. This study may serve as basis for the estimation of the consequences of failure in the evaluation of the risk of operating hazard liquids and natural gas pipelines.
Experimental and Analytical Leak Characterization for Axial Through-Wall Cracks in a Liquids Pipeline
Authors: Chebaro Mohamed R. , Yoosef-Ghodsi Nader , Norfleet David M. , Bergman Jason H. , Sutton Aaron C.
Published: December 2014

Three pipeline sections containing defects of interest were non-destructively tested in the field, cut out and shipped to a structural laboratory to undergo full-scale testing. The common objectives of the experiments were to determine (1) the leak initiation pressure and (2) the leak rate at various specified internal pressures. While two spools (Specimens A and B) contained through-wall cracks, the third (Specimen C) had a partial through-wall crack with similar characteristics. The capacity of through-wall defects to withstand a level of internal pressure without leaking is due to the resultant local, compressive hoop residual stresses. Specimen C underwent full-scale pressure cycling to further comprehend the crack propagation mechanism in order to correlate it to field operation and analytical fatigue life predictions.

To enhance the understanding of the physical crack behaviour as a function of internal pressure, a comprehensive finite element analysis (FEA) model was built using SIMULIA’s Abaqus software. The model inputs incorporated results from the above-mentioned laboratory tests, in addition to extensive radial, circumferential and axial residual stress measurements using the X-ray diffraction (XRD) technique, obtained on three pipe spools cut out from the same line. The resulting crack opening parameters from FEA were input into a closed-form fluid mechanics (FM) model, which was calibrated against a computational fluid dynamics (CFD) model, to determine the corresponding leak initiation pressures and leak rates. These outcomes were then compared to experimental findings. The FEA and FM models were subsequently employed to carry out a parametric study for plausible combinations of feature geometries, material properties, operational pressures and residual stresses to replicate field conditions.

The key outcome from this study is the experimental and analytical demonstration that, for given fluid properties and pressures, the leak threshold and leak rate for through-wall cracks are primarily dependent upon the crack geometry and local residual stress distributions.
Identifying Optimal Pigging Frequency for Oil Pipelines Subject to Non-Uniform Wax Deposition Distribution
Authors: Wang Wenda , Huang Qiyu , Li Si , Wang Changhui , Wang Xi
Published: December 2014

Wax deposition in oil pipelines causes reduced throughput and other associated problems. Periodical pigging program can effectively minimize the cost of wax deposition. This paper shows a typical pigging case study for a field pipeline subject to non-uniform wax deposition distribution by using a developed wax deposition model. The model prediction results prove that the wax is distributed in a short, localized accumulation along the first half pipeline. The resultant pressure drop along the pipeline was examined to reveal the effects of non-uniform wax deposition distribution on the pipeline production. In extreme case, the pressure drop of severe localized section increases by 50%, while this value between pump stations is merely 3%. A maximum wax thickness of 2–4 mm is used as a criterion to determine an optimal pigging frequency. The case study pipeline is recommended to be pigged at a frequency of 10 to 15 days, using by-pass pigs.
Track Record of In-Line Inspection as a Means of ERW Seam Assessment in Response to NTSB Recommendation P-09-1, Arising From the Carmichael, MS Rupture
Authors: Kiefner J. F. , Nestleroth J. B. , Beavers J. A. , Maier C. J.
Published: December 2014

The track record of in-line inspection crack detection technology with respect to locating and characterizing seam defects in electric-resistance-welded (ERW) pipe was examined on the basis of 13 tool runs on 741 miles of hazardous liquid and natural gas pipelines. Results for three types of tools were examined: (ultrasonic angle beam, circumferential magnetic flux, and electromagnetic acoustic transducer (EMAT). The methods for validating the locations, types, and sizes of anomalies included in-the-ditch NDE (UT and MT), and removal of pipe for metallurgical investigation and/or burst testing. The work indicates that in-the-ditch NDE is not always reliable for confirming the ILI findings. The metallographic examinations and burst tests sometimes confirmed the ILI findings, but in other cases, they revealed defects did not compare well in size with the anomalies indicated by the ILI or the in-the-ditch NDE. In some cases, anomalies that caused failures in burst tests had not been identified by the ILI. Because the toughness of the bond line region may differ significantly from that of adjacent material, predictions of failure pressure based on ILI-indicated dimensions using a single toughness level are unreliable. It is concluded that significant improvements in ILI crack-detection technologies will be needed in order for pipeline operators to be able to have adequate confidence in the ERW seam integrity of a pipeline inspected by means of an ILI crack-detection tool. It is also concluded that significant improvements of in-the-ditch NDE methods are needed for such methods to be considered a reliable means of validating ERW seam anomalies found by ILI. These results should not discourage the use of technologies for ERW seam integrity assessment. The tools clearly are useful for finding and eliminating some seam defects. Only by continuing to use and develop the tools can pipeline operators expect to see the technologies improve to the point where operators can have a high degree of confidence in the ERW seam integrity of an inspected pipeline.
Small-Scale Testing to Characterize ERW Seam Properties in Response to NTSB Recommendation P-09-1, Arising From the Carmichael, MS Rupture
Authors: Quickel Gregory T. , Beavers John A. , Kiefner John F. , Leis Brian N.
Published: December 2014

On November 1, 2007, a liquid propane pipeline ruptured near Carmichael, Mississippi. Several pipeline industry experts collaboratively concluded the likely origin of the failure was a defect in the longitudinal electric resistance welded (ERW) seam.[1] These experts also noted that a seam-integrity assessment did not prevent the failure. Following the National Transportation Safety Board’s (NTSB’s) public report, they issued Recommendation P-09-1, which called upon the Pipeline and Hazardous Materials Safety Administration (PHMSA) to conduct a comprehensive study to identify actions that can be used by operators to eliminate catastrophic longitudinal seam failures in pipelines, and indicated the required scope. NTSB directed that PHMSA conduct a comprehensive study of ERW pipe properties and the means to assure that they do not fail in service. Battelle contracted Kiefner and Associates, Inc. (KAI) and Det Norse Veritas (U.S.A.), Inc. (DNV) with the objective to assist PHMSA in favorably closing NTSB Recommendation P-09-1.

One of the tasks performed by DNV was to identify the best method(s) to characterize the toughness properties of ERW seams.[2] The objectives of the task were met by performing 1) a literature search to identify current and new practices for characterizing seam weld properties and 2) Charpy V-notch (CVN) impact testing. The findings from the literature search support the use of the Charpy test for the assessment of the toughness of line pipe steels in general, and the ERW weld seams in particular.

CVN testing was performed on specimens 1) where the notch varied in circumferential location from the bond line and 2) on bond line specimens, at and away from seam weld features/defects. The results indicated a significant decrease in the Charpy energy for non-post weld heat-treated (PWHT) pipe with decreasing distance from the bond line. Surprisingly, the Charpy energies (upper shelf) at the bond line were higher adjacent to the five confirmed (lack of fusion) LOF defects compared to away from the defects.

Failure pressure calculations using CorLAS™ on various (direct current) DC ERW failures, where the pipe dimensions, tensile properties, and flaw geometry were known, revealed that very low Charpy energies (<1.4 J, [1 ft·lb] back-calculated) are needed to cause failure. While the data are very limited in this study, they do not support the notion that CVN tests of the bond line can be used in integrity assessments of bond line defects. This paper will outline some basic steps to be performed to establish a range of bond line Charpy energies.
Advanced Strain-Based Design Pipeline Welding Technologies
Authors: Verma Neerav , Fairchild Doug P. , Noecker Fredrick F. , Macia Mario L. , Nissley Nathan E.
Published: December 2014

To meet the increasing worldwide demand for natural gas, there is a need to safely and economically develop remotely located resources. Pipeline construction is a major activity required to connect these remote resources to markets. Such pipeline routes may cross areas containing geohazards such as discontinuous permafrost, active seismicity and offshore ice gouging. These pipelines may be subjected to longitudinal strains above 0.5%. To safely design pipelines for such conditions, a strain-based design (SBD) approach can be used in addition to conventional allowable stress designs (ASD).

Significant pipeline construction cost savings can be achieved with the use of higher strength steels (X70+) due to reduced pipe wall thicknesses (less steel) and faster girth welding. However, a robust welding technology for higher strength SBD pipelines is often a technology gap depending on the target level of longitudinal strain that needs to be accommodated, since such applications often demand excellent weld toughness at low temperatures (−15°C) and high tensile strength (>120ksi). This paper discusses the development of an enabling welding technology that offers a superior combination of strength and toughness compared to commercially available technologies.

Acicular ferrite interspersed in martensite (AFIM) has been previously identified as a useful high strength weld metal microstructure that can be applied in field pipeline construction. This paper describes how this microstructure has been used to create welds with excellent strength overmatch and good ductile tearing resistance for X80 SBD pipelines. This approach has been implemented for mainline, double-joining and repair welding applications. This paper describes the welding procedures, mechanical properties achieved, estimated strain capacities, and the results of a full-scale pipe strain capacity test.
Development of X90 and X100 Steel Grades for Seamless Linepipe Products
Authors: Toma Diana , Harksen Silke , Niklasch Dorothee , Mahn Denise , Koka Ashraf
Published: December 2014

The general trend in oil and gas industry gives a clear direction towards the need for high strength grades up to X100. The exploration in extreme regions and under severe conditions, e.g. in ultra deep water regions also considering High Temperature/High Pressure Fields or arctic areas, becomes more and more important with respect to the still growing demand of the world for natural resources. Further, the application of high strength materials enables the possibility of structure weight reduction which benefits to materials and cost reduction and increase of efficiency in the pipe line installation process.

To address these topics, the development of such high strength steel grades with optimum combination of high tensile properties, excellent toughness properties and sour service resistivity for seamless quenched and tempered pipes are in the focus of the materials development and improvement of Vallourec.

This paper will present the efforts put into the materials development for line pipe applications up to grade X100 for seamless pipes manufactured by Pilger Mill. The steel concept developed by Vallourec over the last years [1,2] was modified and adapted according to the technical requirements of the Pilger rolling process. Pipes with OD≥20″ and wall thickness up to 30 mm were rolled and subsequent quenched and tempered. The supportive application of thermodynamic and kinetic simulation techniques as additional tool for the material development was used. Results of mechanical characterization by tensile and toughness testing, as well as microstructure examination by light-optical microscopy will be shown. Advanced investigation techniques as scanning electron microcopy and electron backscatter diffraction are applied to characterize the pipe material up to the crystallographic level. The presented results will demonstrate not only the effect of a well-balanced alloying concept appointing micro-alloying, but also the high sophisticated and precise thermal treatment of these pipe products.

The presented alloying concept enables the production grade X90 to X100 with wall thickness up to 30 mm and is further extending the product portfolio of Vallourec for riser systems for deepwater and ultra-deep water application [1, 3, 4].
Examinations Regarding the Sour Gas Resistance of Girth Welds Carried Out on API Grade X80 Seamless Pipe Steel (Heavy Wall)
Authors: Toma Diana , Wiebe Jörg , Niklasch Dorothee , Koka Ashraf
Published: December 2014

Various accessories such as buckle arrestors and J-lay collars are needed in some cases to successfully lay and secure an offshore pipeline on the sea bed. For such applications the using of high strength seamless pipes in Grade X70 and X80 with heavy wall are necessary. However, there is only small information regarding the welding procedure for such grades in heavy wall dimensions.

In comparison to steels used for lower strength level, the chemistry of high strength steel pipes includes higher amounts of micro-alloying elements as well as requires a more complex heat treatment. Due to the higher carbon equivalent these steel grades react more sensitive on heat input during welding. Consequently, the range of welding parameters which ensure suitable mechanical properties has to be adapted.

This article presents the results of weldability trials carried out on seamless API X80 heavy wall (> 50mm) line pipe. The welding trials were performed using different preheating temperatures and heat inputs followed by microstructure investigations and mechanical tests of the multilayer welds. The sour gas resistance has to be demonstrated by SSC-tests because it stays challenging to guarantee values below 250 HV10.
Pipeline Sludge Sampling for Assessing Internal Corrosion Threat
Authors: Garcia Alfonso , Place Trevor , Holm Michael , Sargent Jennifer , Oliver Andrew
Published: December 2014

Internal corrosion sometimes occurs under deposits of solid particles on the bottom of transmission pipelines. The solids trap water with soluble products and other nutrients which can support the development of microbial communities and may lead to Microbiologically Influenced Corrosion (MIC). Corrosion processes associated with the metabolic activities of specific bacteria have been discussed elsewhere, but the simple presence of large microbial populations may increase the risk of internal corrosion owing to the ability of biofilms to extract and concentrate water at the pipe floor.

As a method to monitor the internal corrosion threat in transmission pipelines and recommend mitigating activities for corrosion management, reliable microbial content and corrosion activity correlations are desired. Sludge samples have been obtained from cleaning pigs at the pipe trap and analyzed using Biological Activity Reaction Test (BART™) (or serial dilution test), Dean-Stark analysis, XRD and EDX. These tests provide information about certain bacterial populations, water / solid / hydrocarbon content, and crystalline/elemental composition of these solids, respectively. Despite best efforts, bacterial population/activity of pipeline sludge samples exhibit high variability and are difficult to correlate to actual internal corrosion in a pipeline.

Considering that bacterial populations in pipeline sludge may be a meaningful representation of the internal corrosion threat to a transmission pipeline, a more rigorous approach on the sludge sampling procedure is necessary to improve the accuracy and reliability of the bacterial assays. It is also important to control such variables as storage temperature of the samples, exposure to air, and storage duration prior to enumeration — as these may affect the viability of the sample and enumeration results. This report presents historical pipeline sludge analysis data and suggests a method to evaluate data containing high variability. Practical recommendations to reduce data variability through handling and storage of sludge samples are also discussed.
Horizontal Directional Drilling Application in a Wide River Crossing in the Amazon Rain Forest
Authors: Nóbrega Alves Robson Santana , de Souza Filho Byron Gonçalves
Published: December 2014

Horizontal Directional Drilling, as known as HDD, is a method of construction that requires few trenches or no continuous trenches, used for making crossings under rivers, roads and existing structures. In the oil and gas industry, it is most commonly used in offshore and onshore well drilling activities to better explore the reservoir from a single well. It is also very much used when laying pipelines, where no other feasible option is possible. This technology was widely applied in the Urucu-Manaus natural-gas pipeline construction by Petrobras, and Transpetro has been responsible for the operation and maintenance of this pipeline since November 2009, flowing Natural Gas from the heart of the Amazon forest mainly to the growing market of thermoelectric plants. Due to its extension in the forest, the crossing of numerous wide navigable rivers and other natural obstacles was unavoidable, and no other construction methods were more suitable than the HDD technology. This work shows the application of this method in the 1777m long crossing of the Solimões River during the construction of this 662km Natural Gas pipeline. It also shows the challenges faced due to the logistical adversities in the rainforest, as well as the operations by Transpetro.
Re-Examination of Battelle Two Curve Method
Authors: Lu C. , Michal G. , Godbole A. , Venton P. , Fletcher L.
Published: December 2014

The possibility of fracture propagation is a significant concern for pipelines transporting gases. The need to arrest a running fracture in a pipeline is paramount to the integrity and safety of the pipeline’s operation. The most commonly used method to predict pipe resistance to a ductile fracture is the Battelle Two Curve Method (BTCM). Recent full-scale fracture propagation tests have shown that the BTCM cannot give accurate predictions for modern high-toughness steels.

A Computational Fluid Dynamics (CFD) model has been developed to identify the limitations of the BTCM. The predictions of the developed model are in good agreement with the available experimental data. It has been found from the simulation that the pressure drops very fast in the initial stages of fracture propagation, leading to an intersection between the fracture curve and the decompression curve. However, the fracture speed does not remain constant at the speed corresponding to the intersection point, as assumed in the BTCM. It generally decreases, following the decompression curve as the fracture propagates. This observation indicates that the J-type fracture propagation curve adopted in the BTCM does not accurately represent the fracture propagation behaviour.
Full-Scale Reeling Tests of HFI Welded Line Pipe for Offshore Reel-Laying Installation
Authors: Meiwes Karl Christoph , Höhler Susanne , Erdelen-Peppler Marion , Brauer Holger
Published: December 2014

During reel-laying repeated plastic strains are introduced into a pipeline which may affect strength properties and deformation capacity of the line pipe material. Conventionally the effect on the material is simulated by small-scale reeling simulation tests. For these, coupons are extracted from pipes that are loaded in tension and compression and thermally aged, if required. Afterwards, specimens for mechanical testing are machined from these coupons and tested according to the corresponding standards. Today customers often demand additional full-scale reeling simulation tests to assure that the structural pipe behavior meets the strain demands as well. Realistic deformations have to be introduced into a full-size pipe, followed by aging, sampling and mechanical testing comparable to small-scale reeling.

In this report the fitness for use of a four-point-bending test rig for full-scale reeling simulation tests is demonstrated. Two high-frequency-induction (HFI) welded pipes of grade X65M (OD = 323.9 mm, WT = 15.9 mm) from Salzgitter Mannesmann Line Pipe GmbH (MLP) are bent with alternate loading. To investigate the influences of thermal aging from polymer-coating process one test pipe had been heat treated beforehand, in the same manner as if being PE-coated. After the tests mechanical test samples were machined out of the plastically strained pipes. A comparison of results from mechanical testing of material exposed to small- and full-scale reeling simulation is given. The results allow an evaluation of the pipe behavior as regards reeling ability and plastic deformation capacity.
Site-Specific Quantitative Pipeline Risk Analysis Using Monte Carlo Methods
Authors: Byrd William R. , Wylie Matthew G.
Published: December 2014

This paper compares a site specific quantitative risk analysis for a gas transmission pipeline using traditional “average” risk ranking methods to a more complex Monte Carlo analysis using a range of possibilities and consequences for the various areas of the site—each with their own probability. The comparison is based on the California “Guidance Protocol for School Site Pipeline Risk Analysis”, a quantitative risk analysis protocol which uses average probability and consequence values, and extends it to explain how a more complex Monte Carlo analysis of those same risk factors can give a more comprehensive understanding of anticipated risks and consequences.
Integrity Implications of Unintentionally Expanded Line Pipe
Authors: Rosenfeld M. J.
Published: December 2014

Pipeline construction projects underway in the US during the 2005 to 2010 timeframe encountered occurrences of unintended diameter expansion during hydrostatic testing of high-strength line pipe. Causes of expansion were in some cases attributed to inadequate pipe manufacturing and procurement practices or in other cases to high external loads present concurrently during pressure testing. This paper considers the implications to long-term pipeline integrity arising with pipe that underwent unintended diameter change with associated strain accumulation. The paper presents a relationship between test pressure and diameter expansion, estimation of the reserve strain capacity, effects on fracture control, and effects on integrity reassessment intervals. The conclusions are that the integrity issues associated with limited magnitudes of diameter change can be readily managed.
Refined Modeling Processes and Compressive Strain Capacity Models
Authors: Liu Ming , Zhang Fan , Kotian Kunal , Nanney Steve
Published: December 2014

Local buckling generated by excessive bending and/or longitudinal compression is one of the main threats to pipeline integrity. The resistance to local buckling is usually measured by compressive strain capacity (CSC). Extensive work has been performed on the CSC of pipes through both experiments and numerical modeling. Many CSC models have been developed to compute the CSC.

The comparison of the existing CSC models often shows (1) large differences in recognized input parameters and their applicable ranges, (2) large differences in computed CSC, especially for pressurized conditions, (3) large differences in recommended safety factors; and (4) inconsistent trends on model conservatism.

Refined compressive strain models were developed recently. The development involves comprehensive review of existing CSC models, selecting modeling processes that represent field conditions, sensitivity studies on parameters affecting the CSC, and the model evaluation against experimental data.

In this paper, the refined compressive strain models and the key improvement to the modeling processes are summarized.
Critical Crack Size Detection Criteria to Develop a Novel ILI Tool for Non-Piggable Gas Pipelines
Authors: Al-Muslim Husain , Rosenfeld Michael , Merte David
Published: December 2014

Cracks or crack-like defects have been associated with failures in gas transmission pipelines and gas distribution piping systems, some incidents being consequential. Cracks are identified in natural gas pipeline safety regulations and safety standards as conditions that must be dealt with, however critical sizes or other specific evaluation criteria are not generally given. A hydrostatic test pressure to specified margins above the operating pressure could establish a benchmark for critical sizes that are a potential threat to the integrity of the pipe. Cracks that are too small to fail at the hydrostatic test pressure may still remain present in the pipeline. Ideally, determination of a sufficient margin of safety to identify defects that should be monitored after taking into consideration the potential growth of crack or crack like defects that are too small to fail a hydrostatic test pressure will address defects of concern that may remain present in the pipeline.

The development of an integrated robotic internal inspection tool that can be used to accurately detect and size cracks or crack like features in natural gas pipelines is of mutual interest to pipeline regulators and operators. NDE technology carried by inline inspection tools should be at least capable of identifying cracks or crack like features that would fail in a hydrostatic pressure test or could potentially grow to failure with a high degree of probability prior to the next ILI reassessment. The tool and its integrated software algorithms must be capable of indicating the location, position, orientation, size, and characteristics of defects of interest or concern to minimize validation and/or repair costs and to preserve the overall integrity of pipelines in a gas transmission operator’s integrity management program.

This paper develops criteria for the minimum detection requirements of cracks or crack-like defects by an ILI tool to ensure equivalent integrity to that provided by a hydrostatic pressure test performed to standard requirements. The critical defect sizes will be estimated using fracture mechanics (e.g., the Modified NG-18 equation) considering different toughness categories. The paper addresses the challenge of variability in the real material properties through two approaches. The first approach is to conduct three sets of analyses for each material grade based on the lower 5% percentile, mean and upper 95% percentile properties. The second approach is to conduct the analysis based on Monte Carlo simulations to generate random combinations of material properties as well as crack dimensions.
Under Pressure Welding and Preheat Temperature Decay Times on Carbon Dioxide Pipelines
Authors: Slater Simon , Andrews Robert , Boothby Peter , Barnett Julian , Armstrong Keith
Published: December 2014

Whilst there is extensive industry experience of under pressure welding onto live natural gas and liquid pipelines, there is limited experience for Carbon Dioxide (CO2) pipelines, either in the gaseous or dense phases. National Grid has performed a detailed research programme to investigate if existing natural gas industry under pressure welding procedures are applicable to CO2 pipelines, or if new specific guidance is required. This paper reports the results from one part of a comprehensive trial programme, with the aim of determining the preheat decay times, defined by the cooling time from 250 °C to 150 °C (T250–150), in CO2 pipelines and comparing them to the decay times in natural gas pipelines. Although new build CO2 pipelines are likely to operate in the dense phase, if an existing natural gas pipeline is converted to transport CO2 it may operate in the gaseous phase and so both cases were considered. The aims of the work presented were to:

• Determine the correlations between the operating parameters of the pipeline, i.e. flow velocity, pressure etc. and the cooling rate after removal of the preheat, characterised by the (T250–150) cooling time.

• Compare the experimentally determined T250–150 cooling times with the values determined using a simple one dimensional heat transfer model.

• Define the implications of heat decay for practical under pressure welding on CO2 pipelines.

Small-scale trials were performed on a 150 mm (6″) diameter pressurised flow loop at Spadeadam in the UK. The trial matrix was determined using a one dimensional heat transfer model. Welding was performed on a carbon manganese (C-Mn) pipe that was machined to give three sections of 9.9 mm, 19.0 mm and 26.9 mm wall thickness. Trials were performed using natural gas, gaseous phase CO2 and dense phase CO2; across a range of flow velocities from 0.3 m/s to 1.4 m/s.

There was relatively good agreement between the T250–150 cooling times predicted by the thermal model and the measured T250–150 times.

For the same pipe wall thickness, flow velocity and pressure level, the preheat decay cooling times are longest for gaseous phase CO2, with the fastest cooling rate recorded for dense phase CO2.

Due to the fast cooling rate observed on dense phase CO2, the T250–150 times drop below the 40 second minimum requirement in the National Grid specification for under pressure welding, even at relatively low flow velocities. The practical limitation for under pressure welding of pipelines containing dense phase CO2 will be maintaining sufficient preheating during welding.

The results from this stage of the technical programme were used to develop the welding trials and qualification of a full encirclement split sleeve assembly discussed in an accompanying paper (1).
Microstructural Feature Analysis of X65 Steel Exposed to Ripple Load Testing Under Near Neutral pH Conditions
Authors: Jakupi Pellumb , Santos Bill , Binns Wilfred , Barker Ivan , Been Jenny
Published: December 2014

Newly designed miniature Compact Tension (CT) specimens, designed according to standard ASTM dimension ratios, and machined out of previously in-service X65 pipeline steel were exposed to super-imposed cyclic loading at high mean stresses in NS4 solution to determine the behaviour of X65 steel to ripple loading under near neutral pH conditions. Electron Back-Scatter Diffraction (EBSD) was used to study the microstructural grain geometry to determine if it influences stress-corrosion cracking (SCC) initiation and propagation. Prior to ripple load testing, finely polished X65 surfaces were subjected to EBSD measurements to characterize the microstructure’s geometry; i.e., grain and grain boundary orientations and texture. On the same locations where EBSD maps were recorded, a grid of cross-shaped resist markings — approximately 1–5 μm in size — were deposited every 15 μm across the analyzed surfaces. Following microscopic analyses the specimens were pre-cracked and re-examined to determine whether the crack initiation procedure preconditions the residual strain (quantified by grain misorientations) around an induced crack. Then, ripple load testing at stress levels characterized by load ratios (R) greater than 0.9 was performed, while simultaneously monitoring the open-circuit potential (OCP) at room temperature. The originally characterized surface was again re-examined to determine if the crack tip propagated preferably along a specific crystallographic grain orientation by comparing the shifts in each cross-shaped grid. Results from this investigation will help determine if there is a link between microstructural grain geometries and transgranular stress corrosion cracking.
Bending Deformation Capacity of Large-Diameter Spiral-Welded Tubes
Authors: Vasilikis Daniel , Karamanos Spyros A. , van Es Sjors H. J. , Gresnigt Arnold M.
Published: December 2014

Numerical simulations are conducted to define the bending deformation capacity of large-diameter spiral-welded tubes, towards efficient strain-based design. Under bending loading, the principal failure mode of those tubes is local buckling (wrinkling) of the tube wall. Bending moment, curvature and ovalization are monitored through the numerical analysis, and comparison is conducted with available test data on two 42-inch-diameter tubes, with D/t ratio of 67 and 119, described in detail elsewhere.

The analysis accounts for the actual material properties. Initial geometric imperfections (profile, thickness, ovalization) are obtained from the tested specimens. Furthermore, residual stresses are also considered in the analysis, as computed by a numerical simulation of the cold bending process. A parametric analysis is also conducted on the influence of material properties, geometric initial imperfections and residual stresses on local buckling of spiral-welded tubes. Finally, a comparison with design equations for tube bending deformation capacity is conducted.
Fracture Toughness of X70 Pipe Girth Welds Using Clamped SE(T) and SE(B) Single-Specimens
Authors: Park Dong-Yeob , Gravel Jean-Philippe , Simha C. Hari Manoj , Liang Jie , Duan Da-Ming
Published: December 2014

Shallow-notched single edge-notched tension (SE(T) or SENT) and deep- and shallow-notched single edge-notched bend (SE(B) or SENB) specimens with notches positioned in the weld and the heat-affected zone were tested. Crack-tip opening displacement (CTOD) versus resistance curves were obtained using both a single and double clip gauge consolidated in a SE(T) single-specimen. Up until the peak load the resistance curves from both gauging methods yield approximately the same results; thereafter the curves deviate. Interrupted testing showed that the crack had initiated below 50% of the peak load, and in some cases had propagated significantly prior to reaching the peak load.