bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between Selective Serotonin Reuptake Inhibitors and Risk of Dental Implant Failure
Authors: Carr Alan B. , Gonzalez Ricardo L. Vidal , Jia Li , Lohse Christine M.
Published: January 2019

Purpose

To identify associations between implant failure and selective serotonin reuptake inhibitor (SSRI) medication use in a cohort of consecutive patients receiving dental implants during a 20‐year period.

Materials and Methods

A retrospective review was conducted of all patients who received at least 1 dental implant from January 1, 1995, through December 31, 2014, assessing their history of SSRI use, active SSRI use, and SSRI use during follow‐up with implant failure. Cox proportional hazards regression models assessed associations between demographic characteristics and SSRI use with implant failure, and outcomes were summarized with hazard ratios (HRs) and 95% confidence intervals (CIs). Follow‐up SSRI use was analyzed with time‐dependent covariates.

Results

During the study period, 5456 patients received their first implant (median age, 53 years). The median duration of follow‐up was 5.3 years (interquartile range, 2.3‐10.2 years) for the 4927 patients who did not have implant failure. For the 529 patients who had implant failure, it occurred at a median of 0.5 years. After adjusting for age, sex, and era of implant, history of use of the SSRI sertraline was associated with an increased risk of implant failure among all patients (hazard ratio [HR], 1.60; 95% CI, 1.15‐2.23; p = 0.006) and among the subset of patients with a history of SSRI use (HR, 1.64; 95% CI, 1.07‐2.52; p = 0.02).

Conclusions

In the population reviewed, a history of sertraline use was associated with a 60% greater risk of implant failure; however, active SSRI use at the time of implant placement or during follow‐up was not significantly associated with an increased risk of implant failure.
Using the Big Five Aspect Scales to translate between the HEXACO and Big Five personality models
Authors: Ludeke Steven G. , Bainbridge Timothy F. , Liu Jie , Zhao Kun , Smillie Luke D. , Zettler Ingo
Published: January 2019

Objective

The extensive use of two diverging personality taxonomies (the Big Five and HEXACO models) in contemporary research creates a need for understanding how traits connect to each other across taxonomies. Previous research has approached this at both a highly general (domain‐) level as well as at a highly specific (facet‐) level. The present report is the first to use the intermediate (aspect‐) level of the Big Five Aspect Scales (BFAS) to understand the connections between the two models.

Method

We explored these associations in a meta‐analysis of four samples drawn from three countries (total N = 1,586).

Results

We observed that each HEXACO domain correlated ≥|0.51| with one or more BFAS aspects. Half of the aspects were more strongly associated with HEXACO facets than with HEXACO domains, sometimes markedly so.

Conclusion

Although many domains, aspects, and facets are similarly represented across the two models, this was not always the case. Researchers seeking to use one model to extend findings built primarily off the other should carefully consider how well represented their traits of interest are in the other assessment. Psychology instructors are encouraged to use the BFAS to illustrate the subtler distinctions between the Big Five and HEXACO models.
A Case Study of a New State Model for Assessing Local Wellness Policies
Authors: LeGros Theresa A. , Jones Bete , Jacobs Laurel , Orzech Kathryn M. , Torbert Kinsey , Martinez Stephanie H.
Published: January 2019

BACKGROUND

In 2016, the United States Department of Agriculture issued a final rule to strengthen local wellness policies (LWPs). As school districts pursue compliance, states can provide critical guidance by leveraging support from intermediary programs such as the Supplemental Nutrition Assistance Program—Education (SNAP‐Ed). After Arizona SNAP‐Ed piloted a statewide model for assessing LWPs, we evaluated that model by exploring local SNAP‐Ed agency experiences with the pilot. Our case study objectives were to determine the model's feasibility and utility from the perspective of local agencies supporting school districts during LWP review and revision.

METHODS

We used open‐ended semistructured interviews with the 13 local SNAP‐Ed agencies who engaged in each LWP assessment phase and analyzed data using constant comparative analysis.

RESULTS

Participants found the model feasible and useful. Five themes emerged, 3 of which tracked strongly with successful LWP review and revision: local agency staff comprehension, the openness of local agency staff and district/school personnel to the process, and the local agency's engagement of the district/school throughout the process.

CONCLUSIONS

Leveraging local agency support can be an effective strategy to improving LWPs, given understanding, buy‐in, and staff engagement. Findings can inform agencies seeking to engage intermediaries in LWP assessment and revision.
Substance Use and School Characteristics in Lesbian, Gay, Bisexual, and Heterosexual High School Students
Authors: Fallin‐Bennett Amanda , Goodin Amie
Published: January 2019

BACKGROUND

Tobacco, alcohol, and illicit drug use among lesbian, gay, and bisexual (LGB) high school students as well as related environment and school‐level risk and protective factors were examined.

METHODS

Data was acquired from the 2015 CDC's Youth Behavior Risk Survey for Kentucky (N = 2577). Prevalence of substance use was calculated for all high school respondents by reported sexual orientation. Multivariate analyses estimated the relationship between school and environmental‐level factors (eg, having an adult to talk to) and tobacco, alcohol, and illicit drug use via logistic regressions. Sexual orientation, gender, age, and race/ethnicity were covariates.

RESULTS

LGB students used tobacco, alcohol, and illicit drugs more frequently than their heterosexual counterparts. More LGB teens report facing school risk factors (eg, 37% LGB vs 20% heterosexual bullied at school, p ≤ .001; 17% LGB vs 5% heterosexual ever threatened or injured at school, p < .001; 13% LGB vs 7% heterosexual involved in a school fight, p = .001). Adjusting for school related risk factors, having an adult to talk to was associated with a reduced likelihood of daily smoking (adjusted odds ratio [aOR]: 0.43; 95% confidence interval [CI]: 0.26–0.73), past 30‐day alcohol use (aOR: 0.71; 95% CI: 0.50–0.95), and ever marijuana use (aOR: 0.71; 95% CI: 0.50–1.00).

CONCLUSION

Innovative strategies are needed to create safe, supportive school environments. These strategies are particularly needed in predominately rural states like Kentucky.
A Paleozoic age for the Tunnunik impact structure
Authors: Lepaulard Camille , Gattacceca Jérôme , Swanson‐Hysell Nicholas , Quesnel Yoann , Demory François , Osinski Gordon R.
Published: January 2019

We report paleomagnetic directions from the target rocks of the Tunnunik impact structure, as well as from lithic impact breccia dikes that formed during the impact event. The target sedimentary rocks have been remagnetized after impact‐related tilting during a reverse polarity interval. Their magnetization is unblocked up to 350 °C. The diabase dikes intruding into these sediments retained their original magnetization which unblocks above 400 °C. The impact breccia records a paleomagnetic direction similar to that of the overprints in the target sedimentary rocks. The comparison of the resulting virtual geomagnetic pole for the Tunnunik impact structure with the apparent polar wander path for Laurentia combined with biostratigraphic constraints from the target sedimentary rocks is most consistent with an impact age in the Late Ordovician or Silurian, around 430–450 Ma, soon after the deposition of the youngest impacted sedimentary rocks. Our results from the overprinted sedimentary rocks and diabase dikes imply that the postimpact temperature of the studied rocks was about 350 °C.
The money creation process: A theoretical and empirical analysis for the United States
Authors: Deleidi Matteo , Levrero Enrico Sergio
Published: January 2019

The aim of this paper is to assess—on both theoretical and empirical grounds—the two main views regarding the money creation process, namely the endogenous and exogenous money approaches. After analysing the main issues and the related empirical literature, we will apply a vector autoregression model and a vector error‐correction model methodology to the United States for the period 1959–2017 to assess the causal relationship between a number of critical variables that are supposed to determine the money supply, that is, the monetary base, bank deposits, bank loans and the nominal level of economic activity. The empirical analysis supports several propositions related to the endogenous money approach. In particular, it shows that for the United States in the years 1959–2017 (a) bank loans determine bank deposits and (b) bank deposits in turn determine the monetary base. Our conclusion is that money supply is mainly determined endogenously by the lending activity of commercial banks and the nominal level of economic activity.
Taxonomic notes on Ilex sect. Ilex (Aquifoliaceae) from China I: revision of four species
Authors: Yang Yi , Peng Hua
Published: January 2019

A taxonomic revision of four species of Ilex from China is presented. Ilex dabieshanensis is accepted as the nothospecies I. × dabieshanensis. Six new synonyms are proposed: I. huoshanensis is reduced to a synonym of I. × dabieshanensis from I. centrochinensis, I. urceolatus to I. hylonoma var. glabra, I. kunmingensis var. capitata and I. macrostigma to I. kunmingensis var. kunmingensis, and I. dasyclada and I. tetramera var. glabra to I. tetramera var. tetramera. A nomenclatural account, description, phenology, distribution and habitat, taxonomic notes and specimens cited is provided for each species.
Glycolate from microalgae: an efficient carbon source for biotechnological applications
Authors: Taubert Anja , Jakob Torsten , Wilhelm Christian
Published: January 2019

Glycolate is produced in autotrophic cells under high temperatures and Ci‐limitation via oxygenation of ribulose‐1,5‐bisphosphate. In unicellular algae, glycolate is lost via excretion or metabolized via the C2 cycle by consuming reductants, ATP and CO2 emission (photorespiration). Therefore, photorespiration is an inhibitory process for biomass production. However, cells can be manipulated in a way that they become glycolate‐producing ‘cell factories’, when the ratio carboxylation/oxygenation is 2. If under these conditions the C2 cycle is blocked, glycolate excretion becomes the only pathway of photosynthetic carbon flow. The study aims to proof the biotechnological applicability of algal‐based glycolate excretion as a new biotechnological platform. It is shown that cells of Chlamydomonas can be cultivated under specific conditions to establish a constant and long‐term stable glycolate excretion during the light phase. The cultures achieved a high efficiency of 82% of assimilated carbon transferred into glycolate biosynthesis without losses of function in cell vitality. Moreover, the glycolate accumulation in the medium is high enough to be directly used for microbial fermentation but does not show toxic effects to the glycolate‐producing cells.
Improving organizational newcomers’ creative job performance through creative process engagement: The moderating role of a synergy diversity climate
Authors: Richard Orlando C. , Avery Derek R. , Luksyte Aleksandra , Boncoeur O. Dorian , Spitzmueller Christiane
Published: January 2019

Despite the mounting research demonstrating that employee seniority positively relates to creative job performance, we predict that a synergy diversity climate eliminates the employee seniority–creative job performance relationship by unleashing the creative potential of organizational newcomers. Drawing upon the integration‐and‐learning perspective for managing diversity, Study 1 finds that a synergy diversity climate moderates the relationship between employee seniority and supervisor‐rated creative job performance lending support to our hypothesis. Study 2 provides an extension by showing how creative process engagement mediates this moderating effect on self‐rated creative performance. Finally, Study 3 replicates and extends Study 2 by demonstrating the mediating role of creative process engagement but utilizing supervisor‐rated creative job performance, while again showing synergy diversity climate to be an important boundary condition. In sum, we find that synergy diversity climate, as opposed to fairness and discrimination diversity climate, interacts with employee seniority by facilitating greater creative process engagement for newcomers subsequently impacting creative job performance. We discuss theoretical and practical implications for how the individual‐level creative job performance effects may represent a microfoundation to creative team dynamics that confer a sustainable competitive advantage.
Oscillatory brain activity during acute exercise: Tonic and transient neural response to an oddball task
Authors: Ciria Luis F. , Luque‐Casado Antonio , Sanabria Daniel , Holgado Darías , Ivanov Plamen Ch. , Perakakis Pandelis
Published: January 2019

Intense physical exercise exerts measurable changes at various physiological levels that are well documented in the literature. However, despite the key role of the brain in processing inputs from internal organ systems and the external environment to coordinate and optimize behavior, little is known about brain dynamics during exercise. The present study investigates tonic and transient oscillatory brain activity in a group of participants performing an oddball task during a single bout of aerobic exercise. Twenty young males (19–32 years) were recruited for two experimental sessions on separate days. EEG activity was recorded during a session of cycling at 80% (moderate‐to‐high intensity) of VO2max (maximum rate of oxygen consumption) while participants responded to infrequent targets (red square and big blue circle) presented among frequent nontargets (small blue circle). This was compared to a (baseline) light intensity session (30% VO2max) to control any potential effect of dual tasking (i.e., pedaling and performing the oddball task). A cluster‐based nonparametric permutations test revealed an increase in power across the entire frequency spectrum during the moderate‐to‐high intensity exercise compared to light intensity. Furthermore, the more salient target (red square) elicited a lower increase in (stimulus‐evoked) theta power in the 80% VO2max than in the light intensity condition. Alpha and lower beta power decreased less in the standard trials (small blue circle) during the moderate‐to‐high exercise condition than in the light exercise condition. The present study unveils, for the first time, a complex brain activity pattern during vigorous exercise while attending to task‐relevant stimuli.
Antioxidants and glycine can improve the developmental competence of vitrified/warmed ovine immature oocytes
Authors: Ahmadi Ebrahim , Shirazi Abolfazl , Shams‐Esfandabadi Naser , Nazari Hassan
Published: January 2019

Contents

Despite the numerous potential applications of oocyte cryopreservation, the poor success rate has limited its practical applications. In livestock, particularly in ovine, the oocytes have low developmental competence following vitrification/warming process. Considering the occurrence of osmotic and oxidative stresses during the vitrification/warming process, the application of antioxidants and osmolytes may improve the developmental competence of vitrified/warmed oocytes. In the present study, we aimed to evaluate the effects of the addition of ascorbic acid (AA) and N‐acetyl cysteine (NAC) as antioxidants and glycine as an organic osmolyte either to the vitrification/warming solutions (VWS) or to the IVM medium on the developmental competence of vitrified/warmed ovine germinal vesicle stage oocytes. The survival rate in the vitrified groups was significantly lower than fresh ones. In vitrified/warmed oocytes, there was no significant difference in survival rate between supplemented and non‐supplemented groups. The addition of AA and/or NAC to the VWS or IVM medium and adding glycine to the IVM medium reduced the proportion of apoptotic oocytes and fragmented embryos, which was reflected as an increase in the proportions of metaphase II stage oocytes and blastocyst production. The best result was achieved by supplementing the IVM medium with NAC. In our study condition, antioxidants and glycine could improve the developmental competence of vitrified/warmed ovine immature oocytes, especially when added during IVM.
Middle Class, Government Effectiveness and Poverty in the EU: A Dynamic Multilevel Analysis
Authors: Bosco Bruno , Poggi Ambra
Published: January 2019

Using the 2008‐2011 EU‐Statistics on Income and Living Conditions data, we implement a dynamic three‐level model to analyze poverty persistence in 26 EU countries. We isolate true state dependence phenomena by disentangling the effects of observed and unobserved heterogeneity at country level and employ cofactors not previously considered by the literature. Estimates show that unobserved heterogeneity across individuals remains large, even after explicitly controlling for the observable components of individual characteristics. The initial value of poverty has large effects on current poverty status but this effect is not uniform across countries. The risk of poverty is negatively related to the size of the structural middle class and to the level of structural social expenditure but it increases when lagged total public expenditure increases (with respect to the structural value). There is strong evidence of true state dependence.
Positive affect regulation in youth: Taking stock and moving forward
Authors: Gentzler Amy L. , Root Amy E.
Published: January 2019

This article summarizes the four articles in the Social Development quartet focused on positive affect regulation in youth. Each article in the quartet shows that parents’ socialization of youth positive affect (e.g., encouraging, enhancing, savoring, or dampening responses) is associated with youth positive affect regulation and depressive symptoms. Further, three of the studies provide novel evidence for an indirect relationship whereby parental socialization predicts youth depressive symptoms through youth positive affect regulation. The studies include samples of youth across mid‐childhood and adolescence (7–18‐year‐olds) from three countries (the United States, Belgium, and India), and utilize several methods of assessing youth positive affect regulation or parental socialization (parent‐reported surveys, youth‐reported surveys, coded parent–child discussions). This integrative article also identifies several ways in which the study of youth positive affect regulation can be advanced. We address the conceptualization of positive affect regulation and the socialization of children's positive affect, constraints on the adaptiveness of upregulating positive emotions, methodological directions, potential moderated effects based on child characteristics such as sex or temperament, and the importance of studying outcomes beyond depression.
An extended high‐frequency ultrasound protocol for assessing and quantifying of inflammation and fibrosis in localized scleroderma
Authors: Ranosz‐Janicka Irmina , Lis‐Święty Anna , Skrzypek‐Salamon Alina , Brzezińska‐Wcisło Ligia
Published: January 2019

Background

Clinical characteristics of the lesions are used to identify activity and damage in localized scleroderma (LoS). For high‐frequency ultrasound (HF‐US), the features of active lesions were described.

Materials and Methods

Clinical signs of activity and damage in LoS lesions were assessed with the use of Localized Scleroderma Cutaneous Assessment Tool (LoSCAT) and HF‐US by two examiners independently. All US images were obtained using a 20 MHz HF‐US (DermaLab System, Cortex Technology, Hadsund, Denmark). The dermal thickness (DT) and echogenicity (intensity score, IS) of the LoS lesional dermis were measured in the area of each lesion with the highest score for erythema (ER), skin thickness (ST), and dermal atrophy (DAT). Measurements were compared to the site‐matched unaffected skin. The relative difference of DT and IS values was calculated between each lesion and its normal control for comparison among different clinical scores for ER, ST, and DAT.

Results

A total of 92 lesions in 40 adult patients were examined with HF‐US. Thirty one lesions were erythematous, 26 were in sclerosis, and 35 were in atrophy. A correlation between the clinical evaluation of the LoS lesions and US measurements was found. The sensitivity and specificity of HF‐US were 97% and 90%, respectively. The positive predictive value was 83%, negative predictive value—98%. Interrater reliability was excellent for LoSCAT and HF‐US findings.

Conclusion

High‐frequency ultrasound allows an accurate assessment of the inflammatory and fibrotic skin lesions in LoS.
Making knowledge and meaning in communities of practice: What role may science play? The case of sustainable soil management in England
Authors: Krzywoszynska Anna
Published: January 2019

Social learning is gaining popularity as a tool for understanding and designing interactions between experts and farming communities to enhance the uptake of sustainable and innovative farming practices. To date, the literature has mainly focused on the technical role scientists and researchers play in social learning, as sources of or co‐producers of knowledge. Social learning, however, implies a dynamic between the creation of knowledge (what can be done) and the creation of meaning (what is considered worth doing). This paper addresses this research gap by exploring the roles that “expert” actors and their narratives perform in meaning‐creation. I argue that a sustainable soil management community of practice is emerging in England and discuss the dynamics of farmer participation in this community. I further argue that members of this community use scientific “experts” and narratives to inspire, justify and legitimise sustainable soil management as a valid way of being a “good farmer.” This paper thus stresses the role that scientific or “expert” actors and narratives play in communities of practice as contributors to meaning‐creation inherent to social learning. How soil degradation will be addressed is as much a technical question, a question of what can be done, as a question of meaning, a question of what land managers consider worthwhile doing. The scientific community thus needs to work with the farming community not only to co‐produce technical solutions, but also to co‐produce shared visions of agrarian futures which put soils at their heart.
Meloxicam vs robenacoxib for postoperative pain management in dogs undergoing combined laparoscopic ovariectomy and laparoscopic‐assisted gastropexy
Authors: Bendinelli Cristiano , Properzi Roberto , Boschi Paolo , Bresciani Carla , Rocca Erica , Sabbioni Alberto , Leonardi Fabio
Published: January 2019

Objective

To compare meloxicam and robenacoxib for short‐term postoperative pain management after combined laparoscopic ovariectomy and laparoscopic‐assisted gastropexy.

Study design

Double‐blind, prospective, randomised clinical trial.

Animals

Twenty‐six client‐owned female dogs.

Methods

Dogs undergoing combined laparoscopic ovariectomy and laparoscopic‐assisted gastropexy were randomly divided into 2 groups. Before induction of anesthesia, 13 dogs received meloxicam (0.2 mg/kg subcutaneously), and 13 dogs received robenacoxib (2 mg/kg subcutaneously). Pain was scored with the Glasgow Composite Pain Scale (short form) before surgery and at 1, 6, 12, 18, and 24 hours after extubation. Rescue analgesia (tramadol, 3 mg/kg) was provided to dogs with a Glasgow pain score (GPS) ≥5. Glasgow pain scores were analyzed by ANOVA with treatment, age, and surgical time as fixed factors.

Results

Glasgow pain scores were higher at 24 hours postsurgery in dogs treated with robenacoxib (2.18 ± 0.29) compared with those treated with meloxicam (0.68 ± 0.41, P = .04). Two dogs treated with meloxicam and 7 dogs treated with robenacoxib required rescue analgesia. Regardless of the treatment, the overall GPS was lower at 18 and 24 hours postsurgery when the surgical time was >40 minutes compared with surgical times ≤40 minutes, but surgical site inflammation was likely a confounding factor in this finding. Glasgow pain score was not affected by patient age.

Conclusion

Meloxicam was more effective than robenacoxib at controlling pain in the population of dogs reported here.

Clinical significance

Preoperative administration of meloxicam effectively controls pain for 24 hours after combined laparoscopic ovariectomy and laparoscopic‐assisted gastropexy, but rescue analgesia may be required.
Comparing Three Different Modularity Methods
Authors: Holtta Katja M. M. , Salonen Mikko P.
Published: January 2019

Modularity has many advantages but few methods exist to partition a product into modules, and no knowledge on which method to use and when. This study compares the heuristic method, the design structure matrix, and modular function deployment. The methods are applied on four commercial products. The disturbing result is that, given the same inputs, all methods partition the products differently. Some consider functionality and interface simplicity whereas others focus on strategic factors. A method developed for single products is poorly suited to modularizing product families. The methods find almost no common module boundaries that would be ideal regardless of the method used. This result is not due to poor application of the methods: the repeatability of each method was analyzed. It varied from 68% to nearly perfect. Modular function deployment was the least repeatable whereas the computerized design structure matrix the most repeatable. The heuristic approach fell in between.
Combinatorial Laws for Physically Meaningful Design
Authors: Ramaswamy Vasu , Shapiro Vadim
Published: January 2019

A typical computer representation of a design includes geometric and physical information organized in a suitable combinatorial data structure. Queries and transformations of these design representations are used to formulate most algorithms in computational design, including analysis, optimization, evolution, generation, and synthesis. Formal properties, and in particular existence and validity of the computed solutions, must be assured and preserved by all such algorithms. Using tools from algebraic topology, we show that a small set of the usual combinatorial operators: boundary (∂), coboundary (δ), and dualization (*) — are sufficient to represent a variety of physical laws and invariants. Specific examples include geometric integrity, balance and equilibrium, and surface smoothing. Our findings point a way toward systematic development of data structures and algorithms for design in a common formal computational framework.
Functional Modeling: Toward a Common Language for Design and Reverse Engineering
Authors: Verma Manish , Wood William H.
Published: January 2019

Computer support for future product development must focus on the conceptual design stage where informed decisions make the most impact on design. Working within a systematic, function-based design methodology, we propose modifications to a formal representation originally applied to reverse engineering. In recasting this representation for design capture and reuse, significant barriers have been identified: the language appears to lack expressiveness in key areas, and the representations generated from reverse engineering differ significantly from those used for design. Toward addressing these issues, we augment the language to improve its description of key aspects of design function. In addition, we propose several means of reorganizing reverse engineering information to enhance its reuse in design. Both of these efforts are evaluated in a framework of case-based design, showing significant improvement over the original design representation and pointing toward future improvements.
Functional and Mathematical Equivalence of Mechanisms: A Novel Approach to Integrating Synthesis and Design Analysis
Authors: Yekula Ravi K. , McAdams Daniel A. , Stone Robert B.
Published: January 2019

The objective of our research is to produce classical engineering design analysis models in conjunction with the employment of function based synthesis techniques. As a part of this goal, we define a design approach to construct parametric design models from functional models. Such an approach allows a natural progression from functional product models, to synthesis, to analysis, and then to initial parameter specification. An empirical study is performed to gather product data from a jigsaw and a palm sander. Our method starts by creating a black box model and a functional model of a product. From the functional model, a critical flow and an associated function chain are identified. The next step is to express each component at a functional level. Following that, components are mapped to equations describing their performance and finally, functions are mapped to equations. We analyze product data that is collected following the above described steps and discover functional and mathematical similarities between a scotch yoke mechanism in a jigsaw and an eccentric cam in a palm sander; in this case, two mechanisms used to perform the same function. We derive general performance equations for functions based on the components that are functionally similar but differing in form.
Evolving Engineering Design Trade-Offs
Authors: Antonsson Erik K. , Zhang Yizhen , Martinoli Alcherio
Published: January 2019

In the engineering design process, it is important to know the engineering trade-offs achievable under various design preferences and strategies. In this paper, a family of engineering design trade-offs are evolved from an automatic design synthesis methodology based on evolutionary computation. The complete Pareto optima frontier can be evolved by a consideration of fitness function that aggregates the weighted fuzzy design preferences under different trade-off strategies. An initial case study concerned with the configuration of a collective sensory system is presented and discussed, along with preliminary results obtained from simulations under a specific scenario. The results indicate that the approach can be useful for designers to solve complex engineering problems.
Evaluating a Functional Basis
Authors: Ahmed Saeema , Wallace Ken
Published: January 2019

One of the motivations to develop a standard language to describe the functions of a product or artifact is to facilitate the indexing, search and retrieval of design knowledge. Taxonomies describing a standard language of functions have been developed by a number of researchers. This paper describes an empirical study carried out to evaluate two such taxonomies for their suitability to indexing design knowledge. The results of eighteen interviews conducted into two separate aerospace companies in the UK are presented. Engineering designers were asked to describe the function of assemblies or components that they were familiar with. In total, 207 descriptions of functions were collected. These descriptions have been analysed and compared to the two taxonomies evaluated. This paper describes the findings from these studies and draws conclusions on the suitability of these taxonomies for indexing design knowledge.
Vulnerability of Buried Pipelines to Landslides
Authors: Ferris Gerald , Newton Sarah , Porter Michael
Published: January 2019

The movement of a mass of rock, debris or earth down a slope is a landslide, which in the pipeline industry is often referred to as ground movement. Landslides continue to cause pipeline failures throughout the industry, sometimes as the singular cause of failure and in others cases as a contributing factor to failures (such as stress corrosion cracking on slopes). Landslides can originate on slopes above a pipeline and cause impact loads; they can originate below a pipeline and cause unintended spans; and they can encompass the ground crossed by a pipeline, which can lead to high compressive (or tensile) strains and pipeline buckling. This paper focuses on the latter scenario.

Similar to the approach recently outlined for watercourses [1], the term ‘vulnerability’ refers to the conditional probability of pipeline failure given that landslide movement spatially impacts a pipeline. This paper presents the development of a statistical and judgment-based vulnerability model for pipeline crossings of slopes that are subject to landslides that can be used to rank the relative importance of slopes at a screening level of assessment. The model is based on case histories where this type of landslide scenario caused pipeline failures (defined as holes, leaks and ruptures), or buckling of pipelines that resulted in the need for immediate repairs. Vulnerability has two main uses: on its own to help prioritize large numbers of slope crossings for further investigation; and, once combined with estimates of the probability of landslide movement, to provide a probability of pipeline failure estimate that can be used to guide integrity management programs.
Modeling of Outflow Following Full-Bore Rupture in a Gas Pipeline
Authors: Leung Teresa , Botros Kamal K. , Tomic Aleksandar , Kariyawasam Shahani
Published: January 2019

Accurate prediction of the gas release rate following a full-bore pipeline rupture is key to risk assessment, safe pipeline routing, effective emergency planning and valve closure strategy. Typical tools adopted by the pipeline industry are developed for a perfect gas and are designed to simulate an isolated line rupture event or for simplistic boundary conditions (e.g. constant inlet pressure or no inflow). In the case of a real-life rupture event, a mainline block valve (MLBV) does not respond instantaneously at the time of rupture. Depending on the operation of the pipeline and the configuration of the network itself, the ruptured section might not be isolated for a period of time. Meanwhile, the inlet boundary condition is driven by the upstream network configuration, valve characteristics and operation protocols. As a result, the amount of mass release can be significantly under-estimated by a predictive tool that does not account for these factors.

A program based on the Method of Characteristics was developed, which allows an accurate equation of state and complex boundary conditions that reflect proper upstream conditions and valve closure strategy to be incorporated. An example case demonstrates that a shut-in scenario cannot provide correct out-flow prediction. The resulting outflow amount in a real-life rupture can be a few times higher than a shut-in scenario. This holds important implications in pipeline design, valve closure strategy and risk management.
Valve Characteristics and Their Effect on Transient Surge Pressures in Delivery Terminals
Authors: Perez Emma , El-Bayoumi Ahmed
Published: January 2019

A hydraulic transient occurs when there is a sudden change in the steady state condition of a fluid in a pipeline. The rapid change in velocity of a fluid causes a pressure wave to travel along the pipeline, potentially causing damage to the equipment and piping. Usually, different scenarios are studied depending on whether the fluid is being injected or delivered from the pipeline into a tank. The most commonly studied causes of sudden fluid velocity change in a pipeline are: closing of a fast acting valve (ESD or control valves which close within seconds) and stopping or starting of pumps.

When a pipeline is delivering fluid into a tank, the closure of a valve can completely block the flow and create transient surge pressures that exceed acceptable pressure limits, and require mitigation. Although the closure of a fast acting valve is a commonly analyzed scenario, the closure of a motor operated valve (MOV), which is less commonly analyzed, can also create surge pressures which can put the pipeline at risk. There are three characteristics of an MOV that can significantly impact the surge pressures it creates when it is closed. These valve characteristics are: flow coefficient, valve curve and stroke time.

Hydraulic simulations were performed to study the effect of these three valve characteristics on transient responses when delivering from pipelines into tanks. Simulation results show that a faster stroke time leads to higher pressure surges, as well as a valve with a quick closing or linear curve. However, the flow coefficient of the valves will have varying effects on transients depending on the piping system being analyzed. The purpose of this paper is to not only highlight the importance of valve characteristics when modeling transient surge events but also to provide key learnings that can be used to design safer delivery terminals.
Updated Estimates of Frequencies of Pipeline Failures Caused by Geohazards
Authors: Porter Michael , Ferris Gerald , Leir Mark , Leach Miguel , Haderspock Mario
Published: January 2019

This paper provides an updated compilation of geohazard-related pipeline failure frequencies for onshore hydrocarbon gathering and transmission pipelines, with a particular emphasis on the analysis of data from Western Europe, Western Canada, the US, and South America. The results will be of interest to owners, operators, regulators and insurers who wish to calibrate estimates of geohazard failure frequency and risk on planned and operating pipelines, particularly for pipelines traversing mountainous terrain. It concludes with an estimate of the global annual frequency of failures caused by geohazards on hydrocarbon gathering and transmission pipelines, and postulates that this failure frequency should continue to decline when measured on a per kilometer basis due to ongoing improvements in geohazard recognition, routing and design of new pipelines, and improvements to integrity management practices for operating pipelines.
Full-Scale Pipe Strain Test Quality and Safety Factor Determination for Strain-Based Engineering Critical Assessment
Authors: Fairchild Douglas P. , Crapps Justin M. , Cheng Wentao , Tang Huang , Shafrova Svetlana
Published: January 2019

Generating a tensile strain capacity (TSC) prediction model is a difficult challenge in applied mechanics. Because current models are relatively new and extensive strain-based design (SBD) pipeline service experience does not exist, rigorous model validation using full-scale tests (FSTs) is paramount. The lessons learned from 159 FSTs were presented previously and the data base has grown to 173 tests. This data base is used to assess the accuracy of a relatively new TSC prediction model. The new model simulates a single, surface breaking weld flaw; however, some of the FSTs contained interacting or embedded flaws or unintentional weld defects, while others failed by brittle fracture, and still others experienced welding problems rendering them unsuitable for model validation. Of 173 tests, a smaller number (122, 101, or 89 depending on the goal) is used for comparison to the new model. This paper describes (1) the importance of reliable FSTs, (2) how the 173 tests were judged for suitability in model accuracy assessment, and (3) the use of the FST data to develop a safety factor for strain-based engineering critical assessment (SBECA). The safety factor is generated from a 95% upper confidence limit on the ratio of predicted-to-measured TSC. The safety factor is 1.88. Using the new model and this safety factor, a TSC prediction equation is provided for use in SBECA. The practical meaning of this is that if either TSC or tolerable defect size is calculated using the new model, then the probability of being non-conservative is estimated to be 5%.
Pipeline Route Planning for Multiphase Pipelines
Authors: Kitt Benjamin J. , Licker Aaron , Cull Joshua
Published: January 2019

Pipelines transporting multiphase products (i.e. mixtures of liquids and gas) are common in the upstream oil and gas industry. However, there are numerous flow assurance challenges to the operation of multiphase pipelines, particularly in hilly terrain. For multi-phase pipelines the flow pattern, pressure drop, and associated liquid hold-up within the pipeline is highly dependent on the elevation profile, the gas to liquid ratio, the fluid properties, and the rate of flow. It is desirable to consider how multiphase pipelines can be routed to minimize these operational challenges.

Variation from project to project and the complex nature of multi-phase flow can create challenges to developing common rules of thumb to be used in pipeline routing. There are commercially available software programs that model steady-state and transient flow conditions for multiphase flow, but these programs accept only one set of inputs for a particular routing scenario and the process of finding an optimal pipeline profile through the landscape can become tedious. Consequently, in the author’s experience, it is still common practice to develop pipeline routes for multiphase pipelines using traditional pipeline routing methods that are biased towards pipeline construction rather than operational factors. However, operational cost-savings can be realized through the application of multi-phase flow optimization in early pipeline routing and facility siting.

This paper proposes an alternate method to routing multiphase pipelines using Geographic Information Systems (GIS) based design tools to simultaneously evaluate route options at a landscape level and model the hydraulic behavior of the multiphase flow to identify optimal pipeline routes that minimize the challenges related to multiphase flow. This method allows for proper consideration of the potential construction and operational challenges of multiphase pipelines to be integrated into the pipeline design and balance against various other factors which includes land use, construction methods, terrain challenges and environmental or social impacts. Considering these challenges early in the conceptual design process will help operators realize capital and operational cost savings while allowing for safer and more reliable pipeline operations.

The method uses a multi-criteria approach coupled with a hydraulic model with the ability to balance the influence each factor has on the calculated “least cost path” to route options that improve the flow assurance aspects by strategically navigating the terrain while respecting the host of other factors that contribute or influence the final chosen pipeline route. Using this method, operators can be assured that where opportunities exist to improve the hydraulic performance of a pipeline through route selection, these opportunities will be presented as outputs of the model and expert judgment can be used to determine the final pipeline alignment.
Pipeline Integrity in Seismic and Extremely Cold Regions
Authors: Suzuki Nobuhisa , Arakawa Takekazu , Arabey Andrei
Published: January 2019

This paper discusses seismic integrity of a gas pipeline in extremely cold regions which pipeline consists of X70-grade high-strain line pipes with outside diameter of 1420 mm. Longitudinal compressive strain limits and max longitudinal compressive strain induced by compressive or bending deformation are discussed. The strain capacity in bending of the high strain line pipes tends to be high by 0.5% compared to the largest value within those calculated by some semi-empirical formulae proposed by former researchers. The pipeline may be subjected to axial and/or bending deformation due to ground deformations in discontinuous permafrost zones or stone run areas before an earthquake occurs there. Hence the effects of ground motion and ground deformations should be taken into account simultaneously to investigate the seismic integrity of a pipeline. In order to simply distinguish displacement controlled condition from load controlled condition, parameters including pipe-soil interaction properties are proposed. Design formulae were derived to calculate strain demand of a pipeline to endure the ground deformations, which parameters shall be applied to the deformation in the displacement controlled condition. Finally it was concluded that the high-strain pipes are effective to ensure pipeline integrity in extremely cold and seismically active regions.
Influence of Cold Formed Bending on Strain Based Design Buckling Limits
Authors: Oldfield Tom , Turner Tim , Young Andy
Published: January 2019

Cold formed bends are regularly used in onshore pipeline design to follow the profile and contours of the ground and to ensure any necessary bending is performed under controlled conditions. The cold forming process induces compressive and tensile plastic strains in the pipe wall which remain in the line pipe throughout the service life of the pipeline.

Strain based design of oil and gas pipelines is well established in the offshore environment, where high operating temperatures and pressures have pushed engineers to design more efficient structures through a better understanding of post yield material behaviour and loading mechanisms. The industry standard code DNV-OS-F101 covers the design and limit states for offshore pipeline environments.

There is less experience of strain based design in onshore pipelines, and some of the problems unique to the onshore environment have not been fully investigated.

Low lateral and vertical soil restraints can be observed on a pipeline operating in a desert environment, this in combination with high operational temperature and pressure loading can result in the potential for displacement of the bends. This displacement can induce significant strains in the pipeline. The compressive strains may be sufficient to develop local buckling. Consequently, the local buckling strain represents a key performance limit for the design of the bends.

There is currently no code guidance to include the additional strain component generated by the cold forming process for onshore strain based design. This results in overestimation of the allowable strain capacity of the bends.

This paper investigates how the fabrication of cold formed bends affects the local buckling strain limit and how this reduces the structural capacity of the bend.

Finite Element analysis has been used to assess how the additional strain components, induced during cold formed bending affects the operational capacity of the pipeline. Sensitivity analysis was carried out on a range of unpressurised line pipe, with a diameter to wall thickness ratio varying between 25 and 60, using a specific material model.

Sensitivity analysis indicated a strong correlation between the Finite Element results and those calculated from the local buckling strain limit equation within the industry standard code DNV OS-F-101. The results suggest that an increase in wall thickness, at the bends within a pipeline, could be a solution to offsetting the overestimation in allowable strain capacity due to the cold formed bending process.

Fully understanding the effect that cold form bending has on reducing the local buckling strain limit will promote a more robust design of onshore buried bends under high temperature loads.