bluuebunny/crossref_metadata_2025 huggingface dataset:
Peanut allergy is common among hazelnut‐sensitized subjects but is not primarily the result of IgE cross‐reactivity
Authors: Masthoff L. J. , van Hoffen E. , Mattsson L. , Lidholm J. , Andersson K. , Zuidmeer‐Jongejan L. , Versteeg S. A. , Bruijnzeel‐Koomen C. A. , Knulst A. C. , Pasmans S. G. , van Ree R.
Published: December 2014

Background

Hazelnut and peanut are botanically unrelated foods, but patients are often sensitized and allergic to both, for reasons that are not well understood.

Methods

To investigate molecular cosensitization and cross‐reactivity to peanut in hazelnut‐sensitized individuals, children (n = 81) and adults (n = 80) were retrospectively selected based on sensitization to hazelnut. IgE to hazelnut extract, Cor a 1, 8, 9 and 14, to peanut extract, Ara h 1, 2, 3, 8 and 9, and to Bet v 1 was determined by ImmunoCAP. Allergy to hazelnut and peanut was established by DBPCFC and/or detailed clinical history. Patients were either tolerant or displayed subjective or objective symptoms to either food. IgE cross‐reactivity between hazelnut and peanut storage proteins was assessed by reciprocal ImmunoCAP inhibition experiments.

Results

Of the 161 hazelnut‐sensitized subjects, 109 (68%) were also sensitized to peanut, and 73 (45%) had clinical expression of allergy to peanut that was not associated with the presence or severity of hazelnut allergy. Instead, it was associated with IgE reactivity to peanut storage proteins, in particular Ara h 2. No cross‐reactivity could be detected between Ara h 2 and Cor a 14, and 2 of 13 subjects displayed extensive cross‐reactivity between 11S globulins; in plasma of both individuals, Ara h 3 almost completely inhibited IgE binding to Cor a 9.

Conclusions

Peanut allergy is not primarily the result of IgE cross‐reactivity to hazelnut storage proteins. IgE to Cor a 14 and Ara h 2 may serve as useful markers of primary sensitization to hazelnut and peanut, respectively.
Ventral hernia and patient experience of an elastic girdle
Authors: Strigård Karin , Stark Birgit , Bogren Agneta , Gunnarsson Ulf
Published: December 2014

Background

Abdominal girdles are used to prevent hernia and to facilitate the in‐growth of mesh following ventral hernia surgery or instead of surgery. Scientific evidence supporting the use of girdle, including patient experience, is lacking. The aim was to investigate patient experience of wearing an elastic girdle in terms of support and tolerability.

Methods

A trans‐sectional study with quantitative onset was performed. Telephone interviews following a strict protocol were performed 2 years after girdle prescription. Of the 89 eligible patients, 67 completed the interview. The questionnaire constituted 13 questions.

Results

Of the 52 women and 15 men, two thirds had ventral hernia surgery. Patients over 70 years more often used girdle as a substitute for surgery. Most patients (64%) were satisfied with the girdle and 94% used it as prescribed. Five out of 53 who used girdles preoperatively stated no improvement in their inconvenience. Almost all patients (97%) had some problem with the girdle.

Conclusion

In this first study on patient experience, nearly all patients used it as prescribed and subjective benefit was achieved even though side effects were present in most cases. Individual fitting and improved information about when and how to use the girdle is important for patient comfort and optimal function. This study attended patient experience of negative side effects from wearing a girdle. Improvement may be reached concerning comfort from the patients' perspective. The importance of both written and oral information has been revealed.
A model of urban demography
Authors: Aiura Hiroshi , Sato Yasuhiro
Published: December 2014

This study develops an overlapping generations model that involves the endogenous determination of demographic and city structure to fully analyze the social and natural changes in city populations. We provide conditions under which the model exhibits the spatial features of demography observed in urban areas: city centres have a lower total fertility rate than suburbs and larger cities have a lower total fertility rate than smaller cities. Through calibration, we also show that spatial factors have a significant impact on demographic characteristics and city growth.
Dynamic sorting in durable goods markets with buyer heterogeneity
Authors: Roy Santanu
Published: December 2014

In a competitive dynamic durable good market where sellers have private information about quality, I identify certain inefficiencies that arise due to heterogeneity in buyers' valuations. Even if the market induces dynamic sorting among sellers and all goods are eventually traded, inefficiency can arise because high valuation buyers buy early when low‐quality goods are sold, while high‐quality goods are allocated to low valuation buyers that buy later. This misallocation adds to the inefficiency caused by delay in trading. Under certain circumstances, high‐quality goods may never be traded as in a static market.
Ataxia and myoclonic epilepsy due to a heterozygous new mutation in KCNA2: proposal for a new channelopathy
Authors: Pena S.D.J. , Coimbra R.L.M.
Published: December 2014

We have recently performed exome analysis in a 7 year boy who presented in infancy with an encephalopathy characterized by ataxia and myoclonic epilepsy. Parents were not consanguineous and there was no family history of the disease. Exome analysis did not show any pathogenic variants in genes known to be associated with seizures and/or ataxia in children, including all known human channelopathies. However, we have identified a mutation in KCNA2 that we believe to be responsible for the disease in our patient. This gene, which encodes a member of the potassium channel, voltage‐gated, shaker‐related subfamily, has not been previously described as a cause of disease in humans, but mutations of the orthologous gene in mice (Kcna2) are known to cause both ataxia and convulsions. The mutation is c.890C>A, leading to the amino acid substitution p.Arg297Gln, which involves the second of the critical arginines in the S4 voltage sensor. This mutation is characterized as pathogenic by five different prediction programs. RFLP analysis and Sanger sequencing confirmed the presence of the mutation in the patient, but not in his parents, characterizing it as de novo. We believe that this discovery characterizes a new channelopathy.
Consensus guidelines for diagnosis, prophylaxis and management of Pneumocystis jirovecii pneumonia in patients with haematological and solid malignancies, 2014
Authors: Cooley L. , Dendle C. , Wolf J. , Teh B. W. , Chen S. C. , Boutlis C. , Thursky K. A.
Published: December 2014

Pneumocystis jirovecii infection (PJP) is a common cause of pneumonia in patients with cancer‐related immunosuppression. There are well‐defined patients who are at risk of PJP due to the status of their underlying malignancy, treatment‐related immunosuppression and/or concomitant use of corticosteroids. Prophylaxis is highly effective and should be given to all patients at moderate to high risk of PJP. Trimethoprim‐sulfamethoxazole is the drug of choice for prophylaxis and treatment, although several alternative agents are available.
Consensus guidelines for implementation of quality processes to prevent invasive fungal disease and enhanced surveillance measures during hospital building works, 2014
Authors: Chang C. C. , Ananda‐Rajah M. , Belcastro A. , McMullan B. , Reid A. , Dempsey K. , Athan E. , Cheng A. C. , Slavin M. A.
Published: December 2014

Healthcare‐associated fungal outbreaks impose a substantial economic burden on the health system and typically result in high patient morbidity and mortality, particularly in the immunocompromised host. As the population at risk of invasive fungal infection continues to grow due to the increased burden of cancer and related factors, the need for hospitals to employ preventative measures has become increasingly important. These guidelines outline the standard quality processes hospitals need to accommodate into everyday practice and at times of healthcare‐associated outbreak, including the role of antifungal stewardship programmes and best practice environmental sampling. Specific recommendations are also provided to help guide the planning and implementation of quality processes and enhanced surveillance before, during and after high‐risk activities, such as hospital building works. Areas in which information is still lacking and further research is required are also highlighted.
Dyadic Sexual Communication in Pre-Menopausal Women with Self-Reported Dyspareunia and Their Partners: Associations with Sexual Function, Sexual Distress and Dyadic Adjustment
Authors: Pazmany Els , Bergeron Sophie , Verhaeghe Johan , Van Oudenhove Lukas , Enzlin Paul
Published: December 2014

Introduction

While there is increasing interest in studying aspects of communication processes in sex research, the association between dyadic sexual communication and relationship and sexuality outcomes has not yet been examined in pre-menopausal women with dyspareunia.

Aim

To examine the associations between dyadic sexual communication and pain, sexual distress, sexual function and dyadic adjustment in women with self-reported dyspareunia and their male partners.

Methods

Pre-menopausal women (n = 38; M age = 24.92, SD = 6.12) with self-reported dyspareunia from a community sample and their partners (n = 38; M age = 26.71, SD = 6.59) completed an online survey. The Actor-Partner Interdependence Model was used in order to investigate both actor and partner effects.

Main Outcome Measures

Both members of the couple completed: (i) the Dyadic Sexual Communication Scale and (ii) the Dyadic Adjustment Scale; women also completed (iii) the Female Sexual Function Index, (iv) the Female Sexual Distress Scale, and (v) a Visual Analogue Scale on pain during intercourse; and men also completed (vi) the International Index of Erectile Functioning.

Results

Controlling for relationship duration, women's better dyadic sexual communication was significantly associated with their higher levels of sexual function (P = 0.028), lower levels of sexual distress (P = 0.003) and higher levels of dyadic adjustment (P = 0.005), but not with their pain or men's sexual function or dyadic adjustment. Controlling for relationship duration, men's better dyadic sexual communication was associated with their higher levels of dyadic adjustment (P = 0.027) but not with their sexual function, nor with women's sexual function or dyadic adjustment.

Conclusions

These findings contribute to the theoretical knowledge on interaction processes in couples with dyspareunia and suggest that it may be important to enhance open and direct communication about sexual matters in couples with dyspareunia.
Newly Diagnosed Erectile Dysfunction and Risk of Depression: A Population-Based 5-year Follow-Up Study in Taiwan
Authors: Chou Ping-Song , Chou Wei-Po , Chen Ming-Chao , Lai Chiou-Lian , Wen Yu-Ching , Yeh Kun-Chieh , Chang Wei-Pin , Chou Yii-Her
Published: December 2014

Introduction

Depression might increase the risk of erectile dysfunction (ED), and ED might further exacerbate depression. The causal relationship between these two diseases remains controversial. In addition, limited evidence is available regarding the age-dependent and time-dependent effects on the association of depression and ED.

Aim

We investigated the hypothesis that ED increases the risk of depression by using a nationwide Taiwanese population-based claims database. In addition, we assessed the age-dependent and time-dependent effects on the association of depression and ED.

Methods

A longitudinal cohort study was conducted to determine the association between patients with ED and depression development during a 5-year follow-up period, using claims data from the Taiwanese National Health Insurance Research Database.

Main Outcome Measures

The study cohort comprised patients who were diagnosed with ED during 1997 to 2005 (N = 2,527). For a comparison cohort, 5 age- and sex-matched patients for every patient in the study cohort were selected using random sampling (N = 12,635). All of the patients were followed-up for 5 years from the date of cohort entry to identify the development of depression.

Results

The main finding of this study was that patients with ED are at an increased risk of developing depression. The adjusted hazard ratio (AHR) for depression was 2.24-fold higher in the patients with ED than in the comparison cohort (95% confidence interval [CI]: 1.83–2.74; P < 0.001). Regarding the time-dependent effect, the incidence of depression was highest during the first year of follow-up (AHR: 3.03, 95% CI = 2.08–4.40; P < 0.001).

Conclusions

This study demonstrates that patients with ED are at a higher longitudinal risk of developing depression in Asian men, particularly within the first year after the diagnosis of ED.
Population status and habitat occupancy of endangered river dolphins in the Karnali River system of Nepal during low water season
Authors: Paudel Shambhu , Timilsina Yajna Prasad , Lewis Jennifer , Ingersoll Tom , Jnawali Shant Raj
Published: December 2014

Ganges river dolphin abundance has undergone a predominant decline across its range since monitoring began. In Nepal, disappearance from some of the rivers it once used has already occurred. Today this species can only be found in three river systems in Nepal, the Karnali, Sapta Koshi, and Narayani, but numbers are low in these locations. To determine the abundance of dolphins remaining in the Karnali system (which includes the Karnali, Geruwa, and Mohana), and factors affecting dolphin habitat use, we conducted surveys where we recorded dolphin presence. Dolphins within this river system were sighted only in the Karnali and an abundance estimate of 5.04 ± 0.753 SE was calculated. This pattern of ranging differed from that previously reported (from previous sightings only in the Geruwa to current sightings only in the Karnali). River depth likely contributed to the presence or absence of dolphins. Shifts in available habitat between the Geruwa and Karnali have resulted from changes in the course of the main stream Karnali following construction of the Chisapani irrigation intake. Because of the low numbers of dolphins reported, there is great concern that loss of this species in Nepal is likely in the near future.
Polycomb group proteins – epigenetic repressors with emerging roles in melanocytes and melanoma
Authors: Huang Jennifer M. , Hornyak Thomas J.
Published: December 2014

Melanocytes undergo rapid and significant changes in their gene expression programs at regular intervals during development and the hair follicle cycle. In melanoma, the gene expression pattern found in normal melanocytes is disrupted. These gene expression patterns are regulated in part by post‐translational histone modifications catalyzed by Polycomb group (PcG) proteins, which play a major role in many developmental processes and are often altered in cancer. In this review, we discuss the role of the PcG proteins in stem cell and cancer biology, in general, as well as in melanocyte development and melanomagenesis. Highlights include the discussion of newly identified treatments that target the activity of PcG proteins as well as new developments in the understanding of the role that these proteins play in melanocyte biology.
Shades of American Identity: Implicit Relations between Ethnic and National Identities
Authors: Devos Thierry , Mohamed Hafsa
Published: December 2014

The issue of ethnic diversity and national identity in an immigrant nation such as the USA is a recurrent topic of debate. We review and integrate research examining the extent to which the American identity is implicitly granted or denied to members of different ethnic groups. Consistently, European Americans are implicitly conceived of as being more American than African, Asian, Latino, and even Native Americans. This implicit American = White effect emerges when explicit knowledge or perceptions point in the opposite direction. The propensity to deny the American identity to members of ethnic minorities is particularly pronounced when targets (individuals or groups) are construed through the lenses of ethnic identities. Implicit ethnic–national associations fluctuate as a function of perceivers' ethnic identity and political orientation, but also contextual or situational factors. The tendency to equate being American with being White accounts for the strength of national identification (among European Americans) and behavioral responses including hiring recommendations and voting intentions. The robust propensity to deny the American identity to ethnic minority groups reflects an exclusionary national identity.
Evolution and spread of glyphosate resistance in Conyza bonariensis in California and a comparison with closely related Conyza canadensis
Authors: Okada M , Hanson B D , Hembree K J , Peng Y , Shrestha A , Stewart C N , Wright S D , Jasieniuk M
Published: December 2014

Glyphosate‐resistant weeds are an increasing problem in perennial cropping systems in the Central Valley of California, USA. To elucidate the evolutionary origins and spatial spread of resistance, we investigated the geographical distribution of glyphosate resistance and the population genetic diversity and structure of Conyza bonariensis and compared the results with previously studied C. canadensis. Thirty‐five populations from orchards and vineyards across the Central Valley were sampled. Population genetic structure was assessed using microsatellite markers. Population‐level resistance was assessed in glasshouse screening of plants grown from field‐collected seed. Bayesian clustering and analyses of multilocus genotypes indicated multiple origins of resistance, as observed in C. canadensis. Pairwise FST analysis detected spatial spread of resistance in the south of the Central Valley, also similar to C. canadensis. The results strongly indicate that the southern valley was an environment markedly more suitable than the northern valley for resistance spread and that spread in Conyza species was driven by increased uniformity of strong selection in the southern valley, due to recent regulation on herbicides other than glyphosate. Accordingly, resistant C. canadensis individuals occurred at high frequencies only in the southern valley, but interestingly resistant C. bonariensis occurred at high frequencies throughout the valley. Expression of resistance showed varying degrees of plasticity in C. bonariensis. The lower selfing rate and substantially greater genotypic diversity in C. bonariensis, relative to C. canadensis, indicate greater evolutionary potential over shorter time periods. Interspecific hybridisation was detected, but its role in resistance evolution remains unclear.
Strain Localization in the Dent of a Linepipe
Authors: Oshana-Jajo Jandark , Ghaednia Hossein , Heydariha Jamshid Zohreh , Das Sreekanta
Published: December 2014

Steel pipelines used for transporting oil and gas can develop various damages such as mechanical damages, corrosion, wrinkle, and crack. One of the mechanical damages is a dent with or without other defects such as corrosion, gouge, and crack. The dent without other defect is often referred to as plain dent. Depending on the severity, a dent can lead to a failure of a field linepipe. The strain concentration in a dented pipeline wall can be used to determine the level of severity of a dent. Hence, a research program was undertaken at the Centre for Engineering Research in Pipelines (CERP) using full-scale tests and finite element analyses. The prime objective of this research was to determine comparative strain distributions in and around the dent and locations of high strains developed from the denting process. This information will help the pipeline operators to determine the severity of dents in their field linepipes. Hence, the outcome of this research will allow the pipeline operators to take an informed decision on whether or not an imminent remedial action for the dented segment of the line pipe is required. This paper presents test data and finite element simulation to discuss the locations and values of crucial strains in dents.
Pipeline Plain Dent Fatigue: A Comparison of Assessment Methodologies
Authors: Cunha Sérgio B. , Pasqualino Ilson P. , Pinheiro Bianca C.
Published: December 2014

A collection of results of fatigue tests undertaken on full scale pipeline specimens containing unconstrained plain dents is presented. A total of 61 test results are reported, comprising dents of different shapes and depths, introduced in pipe sections with nominal diameters of 12″ and 24″, D/t ratios varying from 18.6 to 77.2 and made of API 5L X42, X46, X52, X60, X70 and X80 steels. The fatigue test results are used to compare five plain dent fatigue assessment methodologies. The assessment methodologies most widely used in the industry, namely, API 1156 and EPRG, are evaluated; each one of these has two different versions, evaluated independently. A dent assessment methodology previously proposed by the authors is also is included in the study. The classic Palmgren-Miner’s cumulative fatigue damage rule is employed in order to correlate the results, since all tests were carried out with two different pressure cycles. Only two of the evaluated methodologies presented a correlation with the fatigue tests that justifies recommending their application in the industry.
Pipeline Hydrostatic Pressure Test Pass/Fail Criteria Used by a Regulatory Agency
Authors: Edwards Michael
Published: December 2014

This paper describes the development and use of objective and subjective evaluation criteria for hydrostatic pressure tests of oil pipelines at marine terminal facilities by a California state agency. Many regulatory agencies require a periodic hydrostatic pressure test (hydrotest or static liquid pressure test) to re-validate the integrity of a pipeline. Performance variables for a typical test include: test duration, test pressure, test medium temperature, ambient environment temperature, and volumetric changes. At California State Lands Commission, Marine Facilities Division, an Excel spreadsheet is used to evaluate test results. The spreadsheet is also used by many marine oil terminals and contracted testing companies. The spreadsheet aids the user to: perform pretest checks, record input, quantify numerical output, and plot graphical output. The pretest checks include calculating fill volume and determining significant trapped air. The graphical output provides a visual presentation for the test variables of time, test medium temperature, ambient environment temperature, actual test pressure, theoretical test pressure, and allowable pressure variance. Acceptable pressure range is shown as a plus or minus bandwidth around the theoretical test pressure, and is based upon the thermal expansion sensitivity of the test medium. For those test results that fall partially outside the acceptable pressure range, interpretive criteria are used involving data trends and correlations. The spreadsheet software is the property of the State; however, it is freely distributed to anyone who requests a copy. An acceptable hydrostatic pressure test is achieved by adequate test preparation, quality data collection, and quantitative, and often times, interpretive results evaluation.
Correlation of Fracture Behavior in Circumferentially Cracked Pipes and Fracture Specimens Including Ductile Tearing
Authors: Sarzosa Diego F. B. , Ruggieri Claudio
Published: December 2014

This work addresses a two-parameter description of crack-tip fields in bend and tensile fracture specimens incorporating the evolution of near-tip stresses following stable crack growth with increased values of the crack driving force as characterized by the J-integral. The primary objective of this study is to assess the coupled effects of geometry and ductile tearing on crack-tip constraint, as characterized by the J – Q theory, to correlate fracture behavior in circumferentially cracked reeled pipes and common fracture specimens. 3-D finite element computations including stationary and growth analyses were conducted for 3P SE(B) and clamped SE(T) specimens having different notch depth (a) to specimen width (W) ratio. Additional 3-D finite element analyses were also performed for circumferentially cracked pipes with a surface flaw having different crack depth (a) over pipe wall thickness (t) ratios. A cell methodology to model Mode I crack extension in ductile materials was utilized to describe the evolution of J with the evolving near-tip opening stresses. Laboratory testing of an API 5L X70 steel using deeply cracked C(T) specimens was used to measure the crack growth resistance curve for the material and to calibrate the cell parameter defined by the initial void fraction, f0. The present results provide further understanding of crack growth resistance measurements in pipeline steels using SE(T) and SE(B) specimens while eliminating some restrictions against the use of shallow cracked bend specimens in defect assessment procedures.
A Strain Rate-Dependent Finite Element Model of Drop-Weight Tear Tests for Pipeline Steels
Authors: Yu P. S. , Ru C. Q.
Published: December 2014

The influence of crack speed on dynamic fracture toughness of pipeline steel has been observed in some recent tests, although it is still a challenge to obtain a specific relationship between dynamic fracture toughness and crack speed due to the expensive costs of experiments. Meanwhile, the understanding of the dependence of fracture toughness on crack speed is critical for material selection and crack-arrest design in high-strength steel pipelines. The present work develops a strain rate-dependent cohesive zone model and related finite element model to analyze speed-dependent dynamic fracture of pipeline steels observed in recent drop-weight tear tests. Different than most of existing cohesive zone models, the traction-separation law of the present model considers the role of rate of separation, and a strain rate-dependent elastic-viscoplastic constitutive model is employed for the bulk material. The speed-dependences of crack-tip-opening angle (CTOA) and energy dissipation observed in experiments are reproduced in our simulations for crack speed up to 150 m/s. A remarkable feature of the present work is that the present rate-dependent model can predict speed-dependent fracture as a consequence of the strain rate effect even when all fixed material parameters are speed-independent. These results suggest that the strain rate effect in the bulk material could be largely responsible for the speed-dependent dynamic fracture of pipeline steels, and the present rate-dependent model could be used to simulate dynamic fracture of pipeline steels especially when experiments are difficult or too expensive.
Benefits and Methods of Automating Surge Relief Valves
Authors: Konopa John W. , Konopa Kyle A.
Published: December 2014

When using nitrogen loaded surge relief valves it is believed that the relief valve is in control of the upper pressure limit of the pipeline. In reality, it is the nitrogen system together with the valve in a master and slave relationship that sets the upper threshold. The negative effects of changing temperature on the stability of a nitrogen loaded relief valve’s set point is well known but poorly understood. There have been many attempts to minimize this effect. Burying the plenum and using the soil as an insulator has proven to be ineffective. Manual adjustments are not cost effective. Regulators offer inconsistent performance and are often misapplied. Evolving technology now allows for this process to be automated. Set points can be held with remarkable accuracy and plenums no longer need to be buried.
Pragmatic Approach to Estimate Corrosion Rates for Pipelines Subject to Complex Corrosion
Authors: Dann Markus R. , Huyse Luc
Published: December 2014

Corrosion is a common degradation process for most oil and gas pipelines in operation that can lead to leak and rupture failures. To avoid failures due to corrosion, integrity management plans for pipelines require fitness-for-service (FFS) assessments and remaining life analysis of the corrosion features that are detected by in-line inspections (ILIs). The objective of the present paper is to support the deterministic integrity and remaining life assessment of pipelines by introducing a pragmatic approach for the determination of corrosion rates from two inspections. The proposed approach is primarily tailored towards upstream and subsea pipelines that are subject to very high density internal corrosion rather than transmission pipelines with low to moderate densities of external features.

ILI data may be subject to significant measurement errors and feature matching for two ILIs can become highly unreliable if high-density corrosion is present. To address these uncertainties, the backbone of the proposed approach is to focus on corrosion clusters rather than individual corrosion pits and a filtering process is utilized to identify true corrosion growth. The introduced approach is supported by theoretical knowledge and practical experience. The approach can be easily executed in spreadsheet software tools without the application of advanced statistical and probabilistic methods for the deterministic remaining life assessment in practice.
Development of TMCP Type Alloy625/X65 Clad Steel Plate for Pipe
Authors: Tachibana Shunichi , Kuronuma Yota , Yokota Tomoyuki , Mitao Shinji , Sueyoshi Hitoshi , Wada Yutaka , Yabumoto Keizou , Moriya Yutaka , Nagae Moriyasu
Published: December 2014

Demand for CRAs (Corrosion Resistant Alloys) clad steel is getting increased for pipeline application of oil and gas industry because of economic advantage over solid CRAs. CRAs clad steel consists of a CRAs layer for corrosion resistance and a carbon steel for mechanical properties. Nickel based Alloy625 is known to be suitable for harsh environmental condition such as high temperature and high pressure H2S (hydrogen sulfide) condition.

In this paper, the corrosion resistance of Alloy625/X65 clad steel plate for pipe produced by TMCP (Thermo-Mechanical Control Process) was investigated. TTP (Time - Temperature - Precipitation) and TTS (Time - Temperature - Sensitization) diagram of Alloy625 indicated precipitation nose, e.g. M6C and M23C6 which would cause deterioration of corrosion resistance. TMCP enable Alloy625 to avoid long time exposure to the precipitation nose. In Huey test, the corrosion rate in TMCP was almost the same as that of solution treated Alloy625 and smaller than that in Q-T (Quench and Temper). In ferric chloride pitting test, no pitting was observed in Alloy625 layer of TMCP type clad steel. In addition, the corrosion test simulating service environment using autoclave apparatus was conducted under the condition of 0.39MPa H2S - 0.53MPa CO2 - Cl− solution at 200°C. Alloy625 clad steel produced by TMCP showed neither SSC (Sulfide stress corrosion cracking) nor crevice corrosion. All the mechanical properties of base carbon steel satisfied API 5L grade X65 specification by optimizing TMCP conditions. It is notable that 85% SATT of DWTT was below −10 °C. Thus, Alloy625/X65 clad steel plate for pipe produced by TMCP with both superior corrosion resistance and low temperature toughness has been developed.
Assessment of the Reliability Level Embedded in Pipeline Design Codes
Authors: Timashev Sviatoslav , Bushinskaya Anna
Published: December 2014

Recently a long time discussion among specialists about the meaning of the probabilities of failure (POF) produced by different reliability analysis methods surfaced in pipeline journals. This paper, which was a long time in the making, is a follow-up on the discussion and analyses the actual reliability level which was empirically embedded in codes for pipeline design [B31G, B31Gmod, Shell92 and Battelle (PCORRC)] and Building Standard (BR) Main Pipelines #2.05.06-85, using a real pipeline as an example.

Assessment of the actual reliability level empirically embedded in BR is based on assessing the order of the quintiles of strength parameters (design values of tensile strength and yield strength of the pipe material) and load (internal pressure) on the pipeline.

This approach allows direct connection of the deterministic safety coefficients used in the BR with the level of reliability of the pipelines associated with these coefficients.

The actual reliability level, empirically embedded in international codes, is calculated as the probability that the limit state function (LSF) of ideal pipeline (without defects) is positive. LSF = Pf − Pop, where Pf is the failure pressure of an ideal pipe, which is estimated by any design code; Pop is the operating pressure. The failure and operating pressure are considered as random variables. The expression for this probability was obtained analytically and in closed form.

Recommendations are also presented for choosing probability distributions and statistical parameters for random variables RVs. Extensive calculations permitted revealing the reliability levels which are actually present in the analyzed international pipeline design codes. In a nutshell, the paper proves that the international codes under consideration are very reliable, as they produce very safe designs of pipelines with very low POF, and, hence, provide large safety coefficients, and that the algorithm developed in the paper permits connecting the current level of pipeline degradation (in terms of POF), with its current safety coefficient, which, in this case, is a function of time.

All calculating in the paper where performed using MathCAD. Illustrations of these calculations are also presented in the paper.
Consideration of Line-Pack Flexibility in Dynamic Steady-State Simulations for Natural Gas Transport Networks
Authors: Münch Kevin , Körner Hendrik G. E. , Moser Albert
Published: December 2014

Natural gas transport networks have the primary function of transporting natural gas over long distances. Due to the compressibility of gas, a sufficient line pack must exist in the network to provide the contractual delivery pressures. Based on the fact that pressure levels are mostly specified as pressure bands, there is also the possibility to store gas within the network. The gas volume which can be stored and is not necessary for the transport is the line pack flexibility.

In context of the European liberalized market the network operator has the function of managing the gas transport of different actors. Because of forecast deviations, imbalances between gas feed-in and gas feed-out often occur. This is compensated by the use of balancing energy, which can be provided either from external sources or from the line-pack flexibility.

As the necessary line pack for transport varies with each transport situation, this volume must be balanced by the line-pack flexibility. Therefore, a precise knowledge of the line-pack flexibility during the network operation is very important. For this purpose computer-aided simulations are necessary.

Because the increase or decrease of the line-pack flexibility is a transient process, transient simulations should be used. However, transient simulations require a long computing time, which leads to many disadvantages during the network operation. Therefore, this paper develops a method to simulate a natural gas transport network by using fast steady-state calculations under consideration of the transient characteristics of the line-pack flexibility. For this purpose the line-pack flexibility and transient calculation models are analyzed in detail to show the problems using a steady-state approach. Afterwards a method is described to take into account the transient characteristics of the line-pack flexibility. This is verified by exemplary simulations. Finally, the main findings are summarized.
Impact of Small-Scale Reeling Simulation on Mechanical Properties on Line Pipe Steel
Authors: Meiwes Karl Christoph , Erdelen-Peppler Marion , Brauer Holger
Published: December 2014

Reel-laying is a fast and cost effective method to install pipelines since the time consuming operations of welding and inspection are conducted onshore. During reel-laying repeated plastic strain is introduced into a pipeline which may affect strength and ductility of the line pipe material. Based on the experience, it has been shown that the small-scale reeling test procedure according to DNV-OS-F101 [1] is a good way to inspect the mechanical properties for the reel-laying process. Coupons from pipes are loaded in tension and compression tests and aged if required. Specimens for mechanical testing are machined from these coupons and tested according to the corresponding standards.

This paper demonstrates current efforts to demonstrate the usability of cold-formed HFI pipes from Salzgitter Mannesmann Line Pipe GmbH (MLP) for the reel-laying process. In a first step the results of the pre-strained materials are compared in extensive material tests with the undeformed incoming materials. The effect of thermal aging from the coating process on the reeling behavior is then examined, in relation to the background of thermal aging. In discussing the difference between compression and tension zone of the reeled pipe, the influence according to the load conditions is analyzed by the material property tests. This paper demonstrates current efforts of the availability for use of cold-formed HFI pipes for the real-laying process. In addition, the report notes the difference and the effects of the material properties to testing according to the strain-based or stress-based load conditions. In discussing the influence of the tempered conditions of the mechanical properties, therefore two different pipe conditions are investigated by the small scale-reeling (SSR) testing procedure. In summary the results of the pre-strain materials are comparable with the unformed incoming materials.
Comparison of Compressive Strain Limit Equations
Authors: Yoosef-Ghodsi Nader , Ozkan Istemi , Chen Qishi
Published: December 2014

Buried pipelines subjected to non-continuous ground movement such as frost heave, thaw settlement, slope instability and seismic movement experience high compressive strains that can cause local buckling (or wrinkling). In the context of strain-based design, excessive local buckling deformation that may cause loss of serviceability, or even pressure containment in some cases, is managed by limiting the strain demand below the strain limit. The determination of compressive strain limit is typically performed by full-scale structural testing or nonlinear finite element analysis that takes into account material and geometric non-linearity associated with the inelastic buckling of cylindrical shells. Before performing testing and numerical analysis (or when such options do not exist), empirical equations are used to estimate the strain limit. In this paper a number of representative equations were evaluated by comparing strain limit predictions to full-scale test results. Work prior to this study has identified the importance of key variables that have the greatest impact on the local buckling behaviour. Examples of these variables include the diameter-to-thickness ratio (D/t), internal pressure and shape of the stress strain curve. The evaluation presented here focused on how existing equations address these key variables, and the performance of the equations with respect to key variables and in different ranges.
Research on Hydrostatic Test of the Test Pipe Section With a 0.8 Design Factor in the West-to-East China Gas Pipeline III
Authors: Zhang Zhenyong , Liu Yuqing , Zhao Zifeng , Wen Kai , Zhang Jinyuan
Published: December 2014

In order to improve the efficiency of pipeline transportation, a 0.8 design factor is used for gas pipelines in Level 1 area of the western section of West-to-East China Gas Pipeline III for the first time. In accordance with the design requirements, the hoop stress generated in the pipeline strength pressure test should be no less than 100% of the specified minimum yield strength (SMYS). For such a high pressure test strength, there is no domestic experience to follow. This paper studies the approach using P-V curve for pressure test control combined with the actual pressure test of pipelines with a 0.8 design factor and then validates the feasibility and accuracy of such kind of approach through the hydrostatic test of the test pipe section with a 0.8 design factor in the West-to-East China gas pipeline III. Practice has proved that the hydrostatic test of gas pipelines with a 0.8 design factor in Level 1 area is successful and the use of P-V curve method for pressure test control is feasible. This great success accumulates a wealth of experience for the application of pipelines with a 0.8 design factor in Level 1 area, laying a good practice foundation for the promotion of 0.8 design factor in Level 1 area of China.
Field Testing of Pipeline Trench Backfill Properties
Authors: McAffee Rodney , Phillips Ryan , Martens Michael
Published: December 2014

The soil response around a high temperature pipeline proposed for construction in northern Alberta was evaluated. The objective of the field testing program was to gain a better understanding of the engineering properties of the backfill material placed in the trench around a pipeline when subjected to cyclic loading. This is required for the strength and stiffness of these backfill materials in order to improve the predictions related to pipe restraint and movements of the pipe during the cyclic loading anticipated from the thermal cycles.

Specialized field tests were carried out to measure the stiffness of backfill materials within the trench and of the undisturbed native material. Tests were completed along the proposed right-of-way in the native undisturbed soils and then repeated in the “fresh” backfill materials. In addition, field tests were completed over an existing pipeline to assess the effects of “aging” on the backfill materials. Overall, the test results show a significant reduction in the strength and stiffness of the backfill materials as well as a moderate improvement as the materials age with time. However, even “aged” backfill has a much lower strength and stiffness when compared to the native undisturbed soils. The results from the field testing program were incorporated into the numerical models being used to evaluate the performance of the pipeline.
Structural Integrity of Steel Hydrocarbon Pipelines With Local Wall Distortions
Authors: Pournara Aglaia E. , Karamanos Spyros A. , Papatheocharis Theocharis , Perdikaris Philip C.
Published: December 2014

Local distortions on pipeline wall in the form of dents or buckles may constitute a threat for the structural integrity of the steel pipeline. In the present paper, experimental research supported by numerical simulation is reported to investigate the structural integrity of smoothly dented steel pipes. A series of six (6) full-scale experiments on 6-inch X52 pipes has been carried out, and numerical simulations have also been conducted. The dented steel pipes are subjected to cyclic loading (bending or pressure) in order to estimate their residual strength and remaining fatigue life. The finite element analysis simulate the experimental procedure for each type of deformation and loading case, in order to estimate the local stress and strain distributions at the dented region. Based on the numerical results, fatigue life is predicted and compared with the experimental results. The results of the present study are aimed at evaluating existing guidelines and methodologies towards appropriate assessment of local wall distortions in steel pipelines.
Revision to the UK Pipeline Quantitative Risk Assessment Guidelines IGEM/TD/2 and PD 8010-3
Authors: Goodfellow Graham D. , Haswell Jane V. , Jackson Neil W. , Ellis Roger
Published: December 2014

The United Kingdom Onshore Pipeline Operators Association (UKOPA) was formed by UK pipeline operators to provide a common forum for representing pipeline operators interests in the safe management of pipelines. This includes ensuring that UK pipeline codes include best practice, and that there is a common view in terms of compliance with these codes.

Quantitative risk assessment (QRA) is used by operators in the UK to determine if individual and societal risk levels at new developments adjacent to existing pipelines are as low as reasonably practicable (ALARP). In 2008 the UKOPA Risk Assessment Working Group developed codified advice on the use of QRA applied to land use planning assessments, which was published by the Institution of Gas Engineers & Managers (IGEM) and the British Standards Institute (BSI). This advice was designed to ensure a standard and consistent approach, and reduce the potential for disagreement between stakeholders on the acceptability of proposed developments.

Since publication of IGEM/TD/2 and PD8010-3 in 2008, feedback from users of the guidance together with new research work and additional discussions with the UK safety regulator, the Health & Safety Executive (HSE), have been undertaken and the codified advice has been revised and reissued in June 2013.

This paper describes the revisions to the guidance given in these codes in relation to:

• Clarification on application

• Update of physical risk mitigation measures (slabbing and depth of cover)

• Update of HSE approach to Land Use Planning

• Update of failure frequency data:

○ Weibull damage distributions for external interference

○ Generic failure frequency curve for external interference

○ Prediction of failure frequency due to landsliding

The revised codes, and their content, are considered to represent the current UK best practice in pipeline QRA.
Considerations in Planning and Managing a Large Software Development Project
Authors: Milton Dave C.
Published: December 2014

While the pipeline industry is no stranger to complex and expensive projects, the unique characteristics of a truly large software development project require a special set of considerations. Many companies are finding themselves undertaking such a project in order to manage growth, achieve efficiencies, adjust to a new business driver, or simply to replace aging legacy systems. Without the proper attention to topics such as vendor selection, off-shore resourcing, the role of the internal IT shop, testing and training, these projects are almost sure to cost more, take longer and under deliver benefits compared to the original plan and justification.
Towards Effective Pipeline Integrity Decision Making Under Uncertain Environment
Authors: Hassanien Sherif , Sporns Ryan , Gomez Johana , Liang Jeff
Published: December 2014

Pipeline integrity operators often face the challenge of rendering critical decisions even when there is uncertainty in some portion of essential input data. The decision making process can be further complicated by multiple possible courses of integrity action, each of which may contain their own specific uncertainties. This paper presents a multi-attribute decision making process to assist integrity managers in prioritizing and selecting integrity activities necessary for maintaining the safety of their system The proposed approach tackles decisions/actions prioritization process of integrity solutions based on engineering analysis, logistical issues, and availability of the pipeline to deliver the intended capacity; all while maintaining an appropriate safety level. The complexity of some integrity decisions could be better represented through priority versus probability/reliability because there are elements whose contribution or influence is not probabilistic, but nevertheless are describable in terms of priorities. Hence, the proposed approach focuses on two types of uncertainties; uncertainty on available information, and uncertainty about the range of judgments used to express preferences of feasible integrity actions. Integrity actions can take different forms, including excavating a considerable amount of pipeline, applying point or discharge pressure restrictions, executing validation digs, increasing in line inspection frequency, running complimentary in-line inspection technologies, or some combination of these integrity actions. The complexity of optimizing integrity decision arises not only from uncertainties on information, but also from resource availability and feasibility of the various possible integrity actions.