bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the addition of chlorhexidine and miswak extract on the clinical performance and antibacterial properties of conventional glass ionomer: an in vivo study
Authors: Kabil Noha Samir , Badran Amira Saad , Wassel Mariem Osama
Published: October 2016

Background

Antibacterial restorations can increase the success rate of minimum invasive dentistry especially in young permanent molars with deep carious lesions as an attempt to preserve maximum dental structure and avoid pulp exposure. Further research is warranted to evaluate different antibacterial agents.

Objectives

This study aimed to evaluate the efficacy of adding chlorhexidine gluconate (CHX) or aqueous miswak (Salvadora persica) extract on the clinical performance and in vivo antibacterial activity of conventional anhydrous glass ionomer cement (GIC).

Design

The study was a randomized clinical trial. Sixty young permanent molars, with deep carious lesions in 6‐ to 9‐year‐old children were included. After randomization, atraumatic restorative treatment (ART) or stepwise excavation was performed followed by bacterial sampling from the center of the remaining carious dentine in the floor of the pulp. GIC powder was mixed with 0.5% chlorhexidine gluconate liquid in group I; with 100% aqueous miswak in group II; and with deionized water in group III (control). Clinical performance for all groups was assessed at 3, 6, and 9 months. After 9 months, restorations were removed and a second bacterial sample was collected for Streptococcus mutans (S. mutans) quantification and analysis by real‐time polymerase chain reaction (PCR) test.

Results

Results showed no statistically significant difference in the success rate of the three groups at the 3‐month interval. At 6 and 9 months, however, restoration success was 75% then 60% in group I, 100% then 90% in group II, and 95% then 85% in control group. Group II and the control group showed statistically significant higher survival rates than group I. All groups showed reduction in S. mutans counts in underlying dentine, but the percent reduction was significantly higher in group I. (P < 0.001).

Conclusions

The addition of CHX and miswak to GIC showed superior antibacterial properties than conventional GIC, without seriously affecting the clinical performance of the restoration until the 6‐month follow‐up, but failure significantly increased in terms of marginal defects at 9 months with CHX (group 1).
Cross‐group friendships and outgroup attitudes among Turkish–Kurdish ethnic groups: does perceived interethnic conflict moderate the friendship‐attitude link?
Authors: Bagci Sabahat C. , Çelebi Elif
Published: October 2016

We investigated associations between cross‐group friendships, perceived interethnic conflict, and outgroup attitudes in the context of intractable Turkish–Kurdish conflict in Turkey. Measures of cross‐group friendship quantity, perceived conflict, outgroup attitudes, multiculturalism, and outgroup responsibility for conflict were completed by Turkish (N = 320) and Kurdish (N = 153) participants (Mage = 21, 156 males, 317 females). Both cross‐group friendships and perceived conflict were related to outcome variables. While cross‐group friendships were beneficial for both groups’ outgroup attitudes when perceived conflict was lower; when perceived conflict level was higher, positive associations between friendships and attitudes became non‐significant for the Turkish group and negative for the Kurdish group. Implications of the findings for the intergroup contact theory have been discussed.
Role Dynamics in a Structured Relationship: The EU–China Strategic Partnership
Authors: Michalski Anna , Pan Zhongqi
Published: October 2016

In this article, we investigate the function of strategic partnerships as a new type of state interaction in the international system. We are primarily interested in the dynamics of strategic partnerships and to that aim we analyze the competitive role‐playing that occurs in the EU–China Strategic Partnership. We contend that EU and China engage in competitive role‐playing in order to enhance their position and status as global actors and to seek recognition of their international roles. The interaction between the EU and China is analyzed throughout four periods in which their role conceptions have undergone change and adaptation. The article claims to make a theoretical contribution by developing the understanding of social interaction in the international system by conceptualizing strategic partnerships as arenas (structures) in which international roles play out, and an empirical contribution by tracing the complexities of the EU–China Strategic Partnership by utilizing role theory's conceptual apparatus.
Survival of enteric viruses during yoghurt making process using male‐specific coliphage
Authors: Moradi Moghadam Somayeh , Yavarmanesh Masoud , Habibi Najafi Mohammad Bagher
Published: October 2016

The effects of yoghurt‐making process on the survival of male specific coliphage (MS2) in raw milk with different fat content, as well as the survival of MS2 during the storage of yoghurt were evaluated. All samples were analyzed for pH, acidity, and virus count. The results showed that the heat treatment of milk (85 °C, 30 min) decreased the recovery of coliphage MS2 from approximately 7 to 0.97 and 1.49 log10 (pfu/ml) in the milk samples with 2.5% and 3% fat, respectively. No MS2 could be detected in the heat‐treated milk sample with 1.5% fat. The recovery of MS2 during incubation was decreased as the acidity increased particularly in milk with 1.5% fat. Moreover, during the storage time (10 days), yoghurt samples with 1.5% and 3% fat had the lowest and the highest recovery for coliphage MS2, respectively.

Practical applications

Enteric viruses have been reported in dairy products such as pasteurized milk, cheese, and yoghurt. Bacteriophages are viruses that infect bacteria, and exist in ecosystems in which bacteria have been located. A case in point is the vats that are used for the fermentation of yoghurt and other dairy products. This phenomenon renders bacteriophages suitable as surrogates for the evaluation of the survival of enteric viruses in foodstuffs, as is outlined in the present work and similar studies. Due to the health concerns caused by enteric viruses, as well as an increase in the consumption of dairy products, a considerable need for further investigation of their survival is recognized. In order to achieve this aim, researchers can take advantage of the procedure applied here, which has proven reliable and practical for the aforementioned purpose.
Ecological factors associated with behavioral problems in vulnerable children
Authors: Choo Jina , Kim Hye‐Jin , Turk Melanie T. , Kim Eun‐Kyung , Yang Kyung‐Sook
Published: October 2016

Aim

Based onMcLeroy's ecological perspective, this study aimed to identify the factors that are associated with behavioral problems among children who were enrolled in community child centers that provide public welfare services for vulnerable children.

Methods

A cross‐sectional survey was conducted among 175 children aged 6–12 years and their parents who were recruited from 16 community child centers in a municipal county ofSeoul,SouthKorea. The children's behavioral problems were reported by their parents and measured by theChildBehaviorChecklist/6–18. As predictor variables, 14 potential factors were selected at multiple ecological levels; parents’ health‐related quality of life was measured by theWorldHealthOrganizationQuality ofLife‐BREF. A multiple linear regression analysis was carried out.

Results

At the intrapersonal level, children's chronic illness was significantly associated with internalizing problems. At the interpersonal level, lower parental health‐related quality of life was significantly associated with internalizing and externalizing problems. At the organizational level, more years since the community child centers were founded was significantly associated with social problems. At the community level, a lower population density in the district in which the community child center was located was significantly associated with internalizing problems.

Conclusion

Among vulnerable children, behavioral problems were significantly associated with a comprehensive array of intrapersonal‐, interpersonal‐, organizational‐, and community‐level factors. These ecological factors that have been identified in the present study need to be considered when developing multilevel, community‐based nursing strategies for preventing and managing vulnerable children's behavioral problems.
A stand‐alone compact EUV microscope based on gas‐puff target source
Authors: TORRISI ALFIO , WACHULAK PRZEMYSLAW , WĘGRZYŃSKI ŁUKASZ , FOK TOMASZ , BARTNIK ANDRZEJ , PARKMAN TOMÁŠ , VONDROVÁ ŠÁRKA , TURŇOVÁ JANA , JANKIEWICZ BARTŁOMIEJ J. , BARTOSEWICZ BARTOSZ , FIEDOROWICZ HENRYK
Published: October 2016

We report on a very compact desk‐top transmission extreme ultraviolet (EUV) microscope based on a laser‐plasma source with a double stream gas‐puff target, capable of acquiring magnified images of objects with a spatial (half‐pitch) resolution of sub‐50 nm. A multilayer ellipsoidal condenser is used to focus and spectrally narrow the radiation from the plasma, producing a quasi‐monochromatic EUV radiation (λ = 13.8 nm) illuminating the object, whereas a Fresnel zone plate objective forms the image. Design details, development, characterization and optimization of the EUV source and the microscope are described and discussed. Test object and other samples were imaged to demonstrate superior resolution compared to visible light microscopy.
LOCAL PUBLIC SERVICE PROVISION AND SPATIAL INEQUALITY IN CHINESE CITIES: THE ROLE OF RESIDENTIAL INCOME SORTING AND LAND‐USE CONDITIONS
Authors: Sun Weizeng , Fu Yuming , Zheng Siqi
Published: October 2016

Spatial inequality refers to unequal access to local public services between high‐ and low‐income households in relation to their residential locations. We examine two hypotheses regarding the role of income sorting and land‐use conditions in shaping spatial inequality in Chinese cities, where residents have little direct influence on local public service provision. First, in the presence of resource indivisibility, travel cost, and location‐based rationing, scarcity of public‐service resources in a city makes access to public services more uneven across neighborhoods, thus exacerbating income sorting and spatial inequality in the city. Second, the exacerbating effect of resource scarcity is mitigated by land‐use conditions that limit income sorting. Estimates of willingness to pay by households of different income levels for public‐service resources across cities corroborate both the exacerbating effect of resource scarcity and the mitigating effect of inclusive land‐use conditions.
Tenofovir versus tenofovir plus entecavir for chronic hepatitis B with lamivudine resistance and entecavir resistance
Authors: Lee S. , Ahn S. H. , Jung K. S. , Kim D. Y. , Kim B. K. , Kim S. U. , Baatarkhuu O. , Ku H. J. , Han K. , Park J. Y.
Published: October 2016

We compared the viral suppressive efficacy of tenofovir disoproxil fumarate (TDF) mono‐rescue therapy (TDF group) and TDF plus entecavir (ETV) combination‐rescue therapy (TDF + ETV group) in chronic hepatitis B (CHB) patients with lamivudine resistance and entecavir resistance. One hundred and thirty‐three CHB patients with lamivudine and entecavir resistance were investigated. Ninety‐six patients were treated with TDF and 37 with TDF + ETV for at least 6 months. We compared the virologic response rate (HBV DNA level <20 IU/mL) between the two groups and identified the predictive factors of treatment outcome. There were no significant differences between the two groups in demographic characteristics. Up to 24 months [median: 18 (range 6‐24) months], 85.4% and 89.2% of the TDF group and TDF + ETV group, respectively, achieved a virologic response (P=.068). Only the HBV DNA level at baseline was significantly associated with a virologic response in the multivariate analysis. In a subanalysis of patients with HBV DNA levels ≥4 log (IU/mL) at baseline, a higher proportion of patients in the TDF + ETV group than the TDF group achieved a virologic response (92.9% vs 68.3%; P<.001), while 90% of patients with HBV DNA (IU/mL) levels <4 log in all both TDF and TDF + ETV groups achieved a virologic response. TDF mono‐rescue therapy is a reasonable option in patients with lamivudine resistance and entecavir resistance. However, the combination strategy should be considered in patients with high baseline HBV DNA levels.
Multidrug‐resistant Fusarium in keratitis: a clinico‐mycological study of keratitis infections in Chennai, India
Authors: Tupaki‐Sreepurna Ananya , Al‐Hatmi Abdullah M. S. , Kindo Anupma J. , Sundaram Murugan , de Hoog G. Sybren
Published: October 2016

In this study, we aimed to present the first molecular epidemiological data from Chennai, India, analyse keratitis cases that have been monitored in a university hospital during 2 years, identify the responsible Fusarium species and determine antifungal susceptibilities. A total of 10 cases of keratitis were included in the study. Fusarium isolates were identified using the second largest subunit of the RNA polymerase gene (RPB2) and the translation elongation factor 1 alpha (TEF1). Antifungal susceptibility was tested by the broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI) methodology. The aetiological agents belonged to Fusarium solani species complex (FSSC) (n = 9) and Fusarium sambucinum species complex (FSAMSC) (n = 1), and the identified species were Fusarium keratoplasticum (n = 7), Fusarium falciforme (n = 2) and Fusarium sporotrichioides (n = 1). All strains showed multidrug resistance to azoles and caspofungin but exhibited lower minimum inhibitory concentration (MIC) to natamycin and amphotericin B. Fusarium keratoplasticum and Fusarium falciforme belonging to the Fusarium solani species complex were the major aetiological agents of Fusarium keratitis in this study. Early presentation and 5% topical natamycin was associated with better patient outcome. Preventative measures and monitoring of local epidemiological data play an important role in clinical practice.
Root avoidance of toxic metals requires the GeBP‐LIKE 4 transcription factor in Arabidopsis thaliana
Authors: Khare Deepa , Mitsuda Nobukata , Lee Seungchul , Song Won‐Yong , Hwang Daehee , Ohme‐Takagi Masaru , Martinoia Enrico , Lee Youngsook , Hwang Jae‐Ung
Published: October 2016

Plants reorganize their root architecture to avoid growth into unfavorable regions of the rhizosphere. In a screen based on chimeric repressor gene‐silencing technology, we identified the Arabidopsis thaliana GeBP‐LIKE 4 (GPL4) transcription factor as an inhibitor of root growth that is induced rapidly in root tips in response to cadmium (Cd).

We tested the hypothesis that GPL4 functions in the root avoidance of Cd by analyzing root proliferation in split medium, in which only half of the medium contained toxic concentrations of Cd.

The wild‐type (WT) plants exhibited root avoidance by inhibiting root growth in the Cd side but increasing root biomass in the control side. By contrast, GPL4‐suppression lines exhibited nearly comparable root growth in the Cd and control sides and accumulated more Cd in the shoots than did the WT. GPL4 suppression also altered the root avoidance of toxic concentrations of other essential metals, modulated the expression of many genes related to oxidative stress, and consistently decreased reactive oxygen species concentrations.

We suggest that GPL4 inhibits the growth of roots exposed to toxic metals by modulating reactive oxygen species concentrations, thereby allowing roots to colonize noncontaminated regions of the rhizosphere.
Neuronal systems and circuits involved in the control of food intake and adaptive thermogenesis
Authors: Caron Alexandre , Richard Denis
Published: October 2016

With the still‐growing prevalence of obesity worldwide, major efforts are made to understand the various behavioral, environmental, and genetic factors that promote excess fat gain. Obesity results from an imbalance between energy intake and energy expenditure, which emphasizes the importance of deciphering the mechanisms behind energy balance regulation to understand its physiopathology. The control of energy balance is assured by brain systems/circuits capable of generating adequate ingestive and thermogenic responses to maintain the stability of energy reserves, which implies a proper integration of the homeostatic signals that inform about the status of the energy stores. In this article, we overview the organization and functionality of key neuronal circuits or pathways involved in the control of food intake and energy expenditure. We review the role of the corticolimbic (executive and reward) and autonomic systems that integrate their activities to regulate energy balance. We also describe the mechanisms and pathways whereby homeostatic sensing is achieved in response to variations of homeostatic hormones, such as leptin, insulin, and ghrelin, while putting some emphasis on the prominent importance of the mechanistic target of the rapamycin signaling pathway in coordinating the homeostatic sensing process.
Bank Internationalization and Firm Exports: Evidence from Matched Firm–Bank Data
Authors: Bronzini Raffaello , D'Ignazio Alessio
Published: October 2016

In this paper we investigate whether new exporter firms have a higher probability of starting to export to the countries where their financing banks have already established their branches. The underlying mechanism we hypothesize is based on the transmission of foreign market knowledge from banks to firms, so as to cut down information barriers to international trade. In those countries where such information is arguably more precious to the firm, we find a significant positive relationship between a firm's probability of beginning to export to one market and the presence in the same market of a branch of the firm's financing bank. Coherently with the mechanism hypothesized, we find a stronger effect for closer firm–bank relationships and when banks have established their branches abroad over a longer time period.
Noise Control Performance Guidelines for Compressor Station Design
Authors: Frank Leslie D. , Maybee Nigel B. , Matthews Neal
Published: October 2016

Gas transmission companies are sometimes disappointed with the results of efforts to control noise from reciprocating and centrifugal compressor packages, including new compressor station designs and retrofit programs. In an effort to begin to standardize noise control equipment specifications and performance testing procedures, the PRCI undertook a project to develop a series of “Guidelines” for implementing engineering noise control designs for compressor station equipment. The project was sponsored by the PRC International (PRCI). The project report consists of eleven stand-alone Guidelines that can be used by gas transmission companies to develop their own noise control specifications for major compressor station equipment. The intent of the Guidelines is to maintain traditional vendor/sub-vendor roles between compressor packagers and component manufacturers while maintaining the practice of vendor design - vendor guarantee. The noise control requirements can be verified by pre-establishing field performance testing methods. Specific field performance testing methods for various typical mechanical equipment are provided in each Guideline.

The Guidelines are structured to draw a distinction between mechanical equipment components which are noise generators, sound attenuators or acoustic radiators, as each requires a different specification format. To fulfill this aspect, a high temperature microphone probe was researched, developed and tested. This piece of hardware, along with the developed measurement methodology, allows optional diagnostical testing of the engine exhaust noise component of compressor station noise. These diagnostics can assist in isolating the noise generated by the engine versus the attenuation provided by the exhaust silencer. The measurement procedures do not require silencer removal from the package or equipment shutdown to test, which thus reduces testing costs.
Managing Environmental Noise Associated With Pipeline Facilities in Canada
Authors: DeGagne David C.
Published: October 2016

Today’s new pipeline projects have to meet countless technical, regulatory, economic, or social requirements before they can go from the drawing board to reality. One of the more recent considerations is in the area of environmental noise. Environmental noise from pipeline facilities is particularly difficult to control because of the complexities of sound propagation and the subjective nature of that sound relative to some receptor. The extent of noise control from facility equipment such as compressors, coolers, piping, valves, blowdown, emergency flares, even telephone horns, therefore, becomes very difficult to estimate. There must be some understanding of baseline expectations from all interested parties. In addition, pipeline operators must treat environmental noise control as an integral part of project concept and design and not as an afterthought or additional non-core responsibility. Environmental noise control is not an additional cost, it is part of the overall cost of the pipeline transportation business.
Benchmarking for Competitive Advantage
Authors: Korpach David , Hutchison Mark
Published: October 2016

Both liquids pipeline and natural gas transportation companies have been confronted with increasing competition over the past several years. Shippers have become far more demanding, insisting that transporters provide more cost effective rates. As a result, pipeline companies are under increased pressure to reduce transportation rates. This scenario is also true for regulated pipelines where shippers are joining forces to pressure transporters to be more creative in their ways of doing business so they can provide lower tolls.

In order to assess their current cost structures and identify the most appropriate areas of their business to focus improvement efforts, pipeline companies have benchmarked their performance against competitors and leaders in the industry.

Companies have used the results from these benchmarking studies for several purposes:

a) understand cost / activity driver relationships;

b) obtain empirical versus anecdotal information;

c) assess their current level of performance;

d) identify opportunities for improvement, focusing efforts on areas with the greatest potential for cost reductions;

e) establishing realistic performance improvement targets;

f) challenge corporate “myths and legends”; and

g) provide insights into leading business practices that have been used by other companies to improve efficiencies.

Results from the benchmarking studies suggest that the pipeline industry is, in general, reacting to this pressure for lower transportation costs. Over the past three years, based on a sample of North American pipeline companies, both liquids and gas pipelines have reported improvements in operating costs on a unitized/normalized basis. These cost reductions have resulted from focusing improvement efforts on key areas of the business where performance was not up to industry standards. Modifying business practices in these areas has been critical in assisting these organizations in reducing costs.

This paper will present a comprehensive approach to conducting pipeline benchmarking studies. Actual performance results for both gas transportation and liquids carriers will be discussed. The results will focus both on current cost levels as well as industry trends. In addition, it will provide insights into initiatives that have been successful in helping reduce cost structures, moving them towards being the “shipper of choice”.
A Cost-Effective Method of Achieving Meaningful Citizen Participation in Public Roadway Pipeline Studies
Authors: Buszynski Mario E.
Published: October 2016

Many proponents of gas pipeline studies using the public roadway for their facilities have trouble encouraging public participation. Problems resulting from a lack of public involvement are documented. A public participation process designed to gather meaningful public input is presented through a case study of a public roadway pipeline study in southern Ontario. Techniques are outlined to effectively stimulate public interest and document the public involvement process. Recommendations are made as to the transferability of this process to other jurisdictions.
Risk Communication, A Component of an Integrated Risk Management Process for Pipeline Operators
Authors: DeGagne David C.
Published: October 2016

It is essential in today’s socio-economic environment that pipeline operators adopt and utilize a comprehensive approach to managing technical, environmental, economic and public safety risks associated with their business. Clearly, this type of approach to risk management would be integrated and include a variety of considerations. For example, one is the technical assessment of the level of safety or risk inherent within the system itself. Another, is the external view held of that system. While the physical system and its associated risk can be identified, evaluated and to some extent controlled, the external view of the risk, however, is an entirely different matter. Making important decisions about risk requires that both the external and internal views be in agreement. When this is not the case, an integrated management plan needs to include a risk communication component.

Simply, risk communication is the purposeful exchange of information about the existence, nature, form, severity or acceptability of risks.1 An effective risk communication strategy will be able to gauge the political and social reaction to a project. If pipeline operators try to establish what a project’s acceptable level of risk is without a purposeful exchange of information with the community the effort will likely fail. The need to look at the “big picture” is paramount. All factors which affect the outcome of the project need to be understood and, in some way, contribute meaningfully to the final product. The most overlooked aspect in risk management is the qualitative assessment of “how does the public perceive the risk?”. Risk analysts use many basic technical assumptions in their risk assessments. They allow their training and faith in the science to be sufficient indicators of the real risk. The public, on the other hand, view risk from a completely different perspective and set of values. Consequently, when attempts are made to quantitatively determine “what is an acceptable level of risk” the outcome must be viewed as incomplete, lacking the critical external input. Experience suggests that the only ones who can truly determine what is an acceptable level of risk are those who must ultimately accept that risk. This is where the power of effective risk communication can play a significant role in the risk management process. While risk analysis can help in understanding the potential of a risk, effective risk communication and public outreach are necessary in understanding the perceptions and concerns of the community.

It seems ironic that corporations dedicate tremendous resources deriving a mathematical estimate of risk that most in the community cannot comprehend much less believe what the numbers are supposed to tell them. This paper will help to explain the fundamentals of risk communication, its ethical use and methods for developing a strategy for outreach programs as part of an integrated risk management plan.
Quantitative Examination of Segregation in Slabs for the Production of Sour Service Linepipe
Authors: Hoh Bernhard
Published: October 2016

Segregation is a major problem to be overcome by producers of HIC resistant steels. Primary segregation is an inherent and unavoidable feature of the solidification process. The constitutive relationship between solid and liquid stage determines microsegregation and it is influenced by the chemical composition of the steel and its cooling rate. Macrosegregation occurs when microsegregated liquids collect and shift through liquid flow.

OREGON STEEL MILLS has conducted systematic measurements on pressure-cast slabs using a computer assisted micro analyzer. This microprobe measures element concentrations over a large area of the specimen. A statistical evaluation based on the frequency distribution of the concentrations forms the basis of a quantitative analysis. From this, characteristic parameters such as the segregation factor and maximum concentration can be derived.

This paper discussed the influence of carbon on segregation structure and on segregation properties of manganese, and compares the results with those of continuously cast slabs.
A Simple Procedure for Synthesizing Charpy Impact Energy Transition Curves From Limited Test Data
Authors: Rosenfeld Michael J.
Published: October 2016

The importance of Charpy V-notch testing of pipe has been well established in the pipeline industry. Until now, it has been necessary to perform a number of tests in order to develop the toughness transition curve. A method is described which makes possible forecasting the full-scale toughness transition from a single subsize test datum to an acceptable degree of accuracy. This is potentially useful where historical test results or material samples available for testing are limited in quantity. Worked examples illustrating the use of the relationships are given.
Limit Loads for Pipelines With Axial Surface Flaws
Authors: Shen G. , Tyson W. R.
Published: October 2016

The limit loads for pipelines with axial surface flaws have been evaluated by using a strip yield model at levels of ligament yield and ligament collapse. The former was defined as that at which the plastic zone first reaches the back surface, and the later is that at which the plastic zone spreads over the entire ligament. The evaluated collapse load has been used to estimate the failure stress of pipelines containing axial surface flaws. Predictions have been compared with existing experimental data.
Validating the Serviceability of IPL’s Line 13
Authors: Kiefner John , Maxey Willard , Smith John , Lazor Robert
Published: October 2016

This paper describes a technical assessment of operating Interprovincial Pipe Line Inc.’s reactivated Line 1 segments from Hardisty, Alberta to Regina, Saskatchewan and active Line 13 segments from Regina to Gretna, Manitoba at a maximum operating pressure equivalent to 80 percent of the test pressure. The assessment addressed the metallurgy and manufacturing methods of the pipe materials, the operating history, the hydrostatic test results, and the analysis of the hydrostatic test failures. From the assessment it was concluded that the existing portions of original Line 1 and all of existing Line 13 that will be used as parts of the proposed New Line 13 are capable of being operated at pressure levels of 80 percent of the 1993/1994 test pressures.
R&D Advances in Corrosion and Crack Monitoring for Oil and Gas Lines
Authors: Atherton D. L. , Czura W. , Krause T. W. , Laursen P. , Mergelas B. , Hauge C.
Published: October 2016

Magnetic Flux Leakage (MFL) inspection techniques for in-line corrosion monitoring of pipelines continue to evolve rapidly. Current R&D is aimed at improving the accuracy and reliability of defect sizing. Major issues are the variability and consequent need to characterize the magnetic properties of the pipes and the effects of line pressure, residual and bending stresses on MFL signals. Magnetic Barkhausen Noise (MBN) measurements are being used to study the stress-induced changes in magnetic anisotropy. Remote Field Eddy Current (RFEC) techniques are being investigated for detection and measurement of stress corrosion cracking in gas pipelines. Anomalous defect source models have improved the detailed explanation of crack defect interactions greatly.
Residual Strength of 48-Inch Diameter Corroded Pipe Determined by Full Scale Combined Loading Experiments
Authors: Grigory Stephen C. , Smith Marina Q.
Published: October 2016

To provide a data base for the confirmation of computational and classical residual strength analyses of corroded pipelines subjected to combined loads, full scale experiments of 48-inch diameter pipe sections with artificial corrosion were conducted. Design of the experiments was guided by the prerequisite of testing pipe sections in full scale such that subsequent corrections for the uniform depth and extent of the degraded region, and D/t ratios were not required. The testing and analysis procedures were progressively developed through three distinct phases of the program: 1) one proof of concept experiment performed on smaller diameter pipe with artificial corrosion subjected to internal pressure and axial bending, 2) five 48-inch diameter pipe tests, each with artificial corrosion, subjected to internal pressure and axial bending, and 3) eight 48-inch diameter pipe tests, each with artificial corrosion subjected to pressure, axial bending, and axial compression. Combined loading on the test specimens followed a predetermined path until failure by either rupture or global buckling occurred, while the elastic-plastic load-deflection and large strain behavior was recorded. The uniform depth, axial length, and circumferential length of the degraded region were selected to represent commonly observed general corrosion dimensions found among in-service pipelines, with the maximum and minimum extents reflecting the typical wall loss characteristics at the girth and seam weld locations. The pipe behavior during the experiments and analyses was ultimately modeled and verified by an elastic-shell model capable of defining failure pressure and curvature for a corroded pipe subjected to combined service loads.

This paper presents details on the test procedures, specimen preparation and design, and complex data acquisition techniques utilized in the generation of required global and location response information. In addition, significant experimental results from the program which enabled the development and validation of a new procedure for the assessment of corroded pipes under combined loads are reviewed.
New Procedures for the Residual Strength Assessment of Corroded Pipe Subjected to Combined Loads
Authors: Smith Marina Q. , Grigory Stephen C.
Published: October 2016

Motivated by the inability to accurately address non-pressure related stresses within the framework of current assessment guidelines, a three phase study aimed at the progressive development of a reliable and readily-useable procedure suitable for the analysis of internally pressurized degraded pipes which sustain large settlement and/or axial loads was performed. To ensure accuracy of the resulting procedure, full-scale experiments and finite element numerical simulations of artificially corroded 48-inch (122-cm) diameter X65 pipes subjected to combined loadings were designed to produce upper and lower bound rupture and global buckling failure envelopes for a given set of representative corrosion dimensions. The evaluation model accommodates combined stresses arising from internal pressure, axial bending, and axially compressive loadings to predict operational margins of safety for a pipe containing discrete or multiple metal loss regions guided by failure criteria which considers two critical failure modes: 1) a von Mises type failure criterion for rupture moment capacity determination, and 2) a global buckling failure criterion for identification of the critical moment capacity approximating collapse of the pipe mid-section due to a reduction in bending stiffness attributed in part to ovalization of the cross-section. The new methodology has been incorporated in the personal computer based program SAFE (Shell Analysis Failure Envelope), developed by Southwest Research Institute (SwRI) for the Alyeska Pipeline Service Company. The user-friendly program allows for definition of combined applied stresses and geometry of the degraded region through implementation of field-obtainable pre-or post-excavation measurements, and employs unique features which provide for the examination of pipe sections exhibiting distinct areas of general corrosion, or “patches,” separated both longitudinally and circumferentially, in a single analysis run.

This paper outlines the model development and validation with supporting experiments and numerical analyses, and extension of the new procedure through sophisticated numerical techniques embodied in SAFE to actual corrosion profiles and service loadings. Detailed information included in the review are the finite element and SAFE program failure predictions for pipes analyzed with a given set of corrosion dimensions and load magnitudes, and a thorough discussion of the practical application of the SAFE program.
Pipeline Failure Investigations: Analytical Techniques and Case Studies
Authors: Wilson Brian R.
Published: October 2016

There are a number of analytical techniques which can be employed during the course of a pipeline failure investigation to assist in the collection of all the pertinent information essential to determining the cause of failure. The key is to select the appropriate analytical techniques at the beginning of the investigation and involve experienced and qualified people in every facet of the examination and testing process. Case studies described in this paper involve stress corrosion cracking, external corrosion on a gas transmission pipeline, cracking of fibreglass line pipe, failure of a new mechanical interference fit pipeline joint and mill defects in a large diameter submerged arc weld seam.
Pipeline SCC in Near-Neutral pH Environment: Recent Progress
Authors: Zheng W. , Revie R. W. , MacLeod F. A. , Tyson W. R. , Shen G.
Published: October 2016

Transgranular stress corrosion cracking in oil and gas linepipe was studied by testing full-scale pipes in soil environments. Three pipes made of Grade 359 (X-52) and Grade 414 (X-60) steels were used. Sixteen cracks were prepared on the external surface of each pipe, and crack growth was monitored and studied as a function of the pressure level and pressure fluctuation, the latter being described by the minimum to maximum stress ratio (R) and the loading rate.

The overall results suggest strong mechanical effects on crack growth. Crack growth rates were found to be affected by both the pressure level and the level and rate of pressure fluctuation. For the Grade 414 pipe, reducing pressure fluctuation by increasing R from 0.6 to greater than 0.97 reduced the crack growth rates to below 5*10−9 mm/s, the detection limit of the crack depth measurement system used. Similar effects of pressure fluctuation were also seen for the Grade 359 pipes.
Stress Corrosion Cracking of a Liquid Transmission Line
Authors: Krishnamurthy Ravi M. , MacDonald Reg W. , Marreck Peter M.
Published: October 2016

Localized corrosion, and the associated stress corrosion cracking compromised the integrity of the 610 mm diameter X-52 Rainbow pipeline. Following incidents of rupture, an extensive excavation effort was undertaken to locate and rehabilitate the line. Limited correlation’s were noted with the type of soil, and the operating line pressure. A elastic-plastic fracture model was developed to manage the SCC on this pipeline. Hydrotests were deemed necessary in certain portions of the line, based on model predictions on susceptibility to failure. Additionally, the model was further applied to define hydrotest frequency.
Factors Influencing Stress Corrosion Cracking of Gas Transmission Pipelines: Detailed Studies Following a Pipeline Failure: Part 1 — Environmental Considerations
Authors: Wilmott Martyn J. , Diakow David A.
Published: October 2016

Following a failure caused by stress corrosion cracking (SCC) on an NPS 8 pipeline in the NOVA Gas Transmission Limited (NGTL) system a detailed investigation was undertaken to understand the contributing factors resulting in the failure. Studies included site characterization using the NOVAProbe, followed by detailed excavation and sampling. In total 1.1 km of pipe was inspected and replaced. This paper will detail the procedures used to investigate the site and the subsequent analysis and characterization of the samples collected. Factors which appear dominant in determining where SCC occurs will be discussed.
Investigation of the Passivity, Hydrogen Embrittlement and Threshold Stress of Duplex Stainless Steel
Authors: Gojić Mirko , Metikoš-Huković Mirjana , Babić Ranko
Published: October 2016

The electrochemical behavior of duplex stainless steel has been studied in various environments. Its passivity state was investigated in borate-buffer using cyclic voltammetry and impedance spectroscopy techniques. The susceptibility towards sulfide stress cracking and hydrogen embrittlement were tested at a constant load under cathodic polarization in the NACE solution saturated with H2S and 0.5 M sulfuric acid solution containing As203 as a promoter. SEM analysis accompanied these investigations.

It is proposed that the highly protective quality of the passive film formed on the investigated duplex stainless steel may be associated with the presence of multiple oxidation states (Cr3+ and Cr6+) formed in the solid state along with (CrO42- and MoO42-) anions and the great variety of possible bridging ligand states (OH−, H2O, O2−). This leads to a significant degree of bonding flexibility and supports amorphous i.e. glassy structure of the passive film. Therefore, the stresses that would be associated with epitaxy, are easily alleviated without the creation of long-range defect structures. The investigated duplex stainless steel shows high resistance to hydrogen embrittlement and sulfide stress cracking. The embrittlement index was determined to be 26%, while the threshold stress amounts to 84% of the yield strength.
Study of Stress-Corrosion Cracks, Physical and Mechanical Properties of Steel After Hydrostatic Re-Testing
Authors: Karpov S. , Korolyov M. , Sergeyeva T.
Published: October 2016

The hydrostatic re-testing of pipelines is one of the general methods of determination of service reliability of pipes in the zones characterized by high risk of stress corrosion.

The detailed complex metal-physics studies of structural and stress-strain state of steel, as well as topography of stress-corrosion cracks, hydrogenation in fragments of pipes damaged at various stages of loading during re-testing were carried out due to the idea of “damage” of steel caused by harmful effect of increased pipes deformation.

Templates of pipes having fractures and zones with or without stress-corrosion defects were cut out for studies. It has been shown that no deterioration of mechanical and ductility properties occurs in the parts of pipes without stress-corrosion defects. No considerable changes of character and degree of cracking as well as cracks topography have been detected during various stages of re-testing.
Mechanisms of High-pH and Near-Neutral-pH SCC of Underground Pipelines
Authors: Beavers John A. , Harle Brent A.
Published: October 2016

This paper provides an overview of mechanisms for high-pH and near-neutral-pH stress corrosion cracking of underground pipelines. Characteristics and historical information on both forms of cracking are discussed. This information is then used to support proposed mechanisms for crack initiation and growth.
Stress Corrosion Crack Growth of Pipeline Steels in NS4 Solution
Authors: Plumtree A. , Lambert S. B.
Published: October 2016

Stress corrosion cracking (SCC) can occur on the soil side of buried natural gas pipelines when the coating breaks down and ground water comes into contact with the pipe surface. A neutral solution and a transgranular crack morphology have been identified with recent field cracking in Canada. A series of experiments have been conducted on fatigue pre-cracked specimens to investigate this type of SCC. Crack growth has been monitored with a direct current potential drop system and fractographic examination. The experimental system developed to investigate the growth of large stress corrosion cracks under relevant field conditions is presented and discussed.
Numerical Investigation of Jamming of Solid Particles in a Straight Pipe
Authors: Sun Yi , Vinogradov Oleg
Published: October 2016

The flow of fluids containing solid particles is numerically simulated in order to determine the critical parameters of the system leading to a jam. Two parameters are varied: the volumetric density of solid particles and the velocity of fluid flow. The energy dissipation in the system is due to dry friction losses and collisions. The results presented are based on the mathematical models of granular materials treated as multibody systems with variable topology. The fluid flow is considered to be potential. It is shown that jamming strongly depends on the volumetric density of particles and fluid velocity. The results of numerical experiments are in qualitative agreement with physical experiments of flow of spherical particles in a pipe.
Pipeline Integrity Design for Differential Settlement in Discontinuous Permafrost Areas
Authors: Zhou Z. Joe , Boivin Raymond P. , Glover Alan G. , Kormann Phil J.
Published: October 2016

The NOVA Gas Transmission Ltd. (NGTL) gas pipeline system is expanding northwards as the producers search for and find new gas reserves. This growth has taken the system into the discontinuous permafrost zone, and also into new design problems. One such problem is the structural integrity of a pipeline subjected to the settlement differentials that occur between frozen and unfrozen soils. Adequate integrity design for differential settlement is required by design codes, such as CSA Z662, but the procedures and criteria must be established by the pipeline designers.

This paper presents the methodology of pipeline integrity design for differential settlements used on a number of pipeline projects in Northwest Alberta. Outlined in the paper are the procedures, rationales and models used to: (a) locate discontinuous permafrost; (b) quantify the potential differential settlement; (c) predict pipeline stresses and strains; (d) establish strain limits; and (e) determine the pipe wall thickness to withstand those potential differential settlements. Several design options are available and are briefly discussed. For the projects mentioned, the heavy wall pipe option was identified as a cost effective design for medium to large differential settlements.