bluuebunny/crossref_metadata_2025 huggingface dataset:
Allometric scaling of seed retention time in seed dispersers and its application to estimation of seed dispersal potentials of theropod dinosaurs
Authors: Yoshikawa Tetsuro , Kawakami Kazuto , Masaki Takashi
Published: January 2019

Seed retention time (SRT), the time interval between seed ingestion and defaecation, is a critical parameter that determines the spatial pattern of seed dispersal created by an animal, and is therefore, an essential component of trait‐based modelling of seed dispersal functions. However, no simple predictive model of SRT for any given animal exists.

We explored the linkage between animal traits and SRT. We collected previously published data on mean SRT for 112 species of birds, mammals, reptiles and fishes and investigated the general allometric scaling of mean SRT with body mass for each taxon. Moreover, we analysed the effects of food habit and digestive strategy on mean SRT for birds and mammals.

In general, mean SRT increased with body mass in all four taxa, whereas the pattern of allometric scaling varied greatly among the taxa. Birds had a smaller intercept and larger slope than those of mammals, whereas reptiles had a much larger intercept and smaller slope than those of either birds or mammals. For birds, food habit was also detected as an important factor affecting SRT. We applied the allometric scaling that was obtained for birds to estimate mean SRT of extinct Mesozoic dinosaurs (Theropoda) – few of which are assumed to have acted as seed dispersers. SRT for large carnivorous theropods was estimated to be 4–5 days, when considering only body mass.

The present study provides allometric scaling parameters of mean SRT for a variety of seed‐dispersing animals, and highlights large variations in scaling among taxa. The allometric scaling obtained could be a critical component of further trait‐based modelling of seed dispersal functions. Further, the potential and limitations of the scaling of animal SRT with body mass and a future pathway to the development of trait‐based modelling are discussed.
Generalists are the most urban‐tolerant of birds: a phylogenetically controlled analysis of ecological and life history traits using a novel continuous measure of bird responses to urbanization
Authors: Callaghan Corey T. , Major Richard E. , Wilshire John H. , Martin John M. , Kingsford Richard T. , Cornwell William K.
Published: January 2019

Identifying which ecological and life history traits influence a species’ tolerance to urbanization is critical to understanding the trajectory of biodiversity in an increasingly urbanizing world. There is evidence for a wide array of contrasting patterns for single trait associations with urbanization. In a continental‐scale analysis, incorporating 477 species and >5 000 000 bird observations, we developed a novel and scalable methodology that evaluated the ecological and life history traits which most influence a species’ adaptability to persist in urban environments. Specifically, we assigned species‐specific scores based on continuous measures of response to urbanization, using VIIRS night‐time light values (i.e. radiance) as a proxy for urbanization. We identified generalized, phylogenetically controlled patterns: bird species which are generalists (i.e. large niche breadth), with large clutch size, and large residual brain size are among the most urban‐tolerant bird species. Conversely, specialized feeding strategies (i.e. insectivores and granivores) were negatively associated with urbanization. Enhancement and persistence of avian biodiversity in urban environments probably relies on protecting, maintaining and restoring diverse habitats serving a range of life history strategies.
The effects of intervessel pit characteristics on xylem hydraulic efficiency and photosynthesis in hemiepiphytic and non‐hemiepiphytic Ficus species
Authors: Li Shuai , Hao Guang‐You , Niinemets Ülo , Harley Peter C. , Wanke Stefan , Lens Frederic , Zhang Yong‐Jiang , Cao Kun‐Fang
Published: January 2019

Xylem vulnerability to cavitation and hydraulic efficiency are directly linked to fine‐scale bordered pit features in water‐conducting cells of vascular plants. However, it is unclear how pit characteristics influence water transport and carbon economy in tropical species. The primary aim of this study was to evaluate functional implications of changes in pit characteristics for water relations and photosynthetic traits in tropical Ficus species with different growth forms (i.e. hemiepiphytic and non‐hemiepiphytic) grown under common conditions. Intervessel pit characteristics were measured using scanning electron microscopy in five hemiepiphytic and five non‐hemiepiphytic Ficus species to determine whether these traits were related to hydraulics, leaf photosynthesis, stomatal conductance and wood density. Ficus species varied greatly in intervessel pit structure, hydraulic conductivity and leaf physiology, and clear differences were observed between the two growth forms. The area and diameter of pit aperture were negatively correlated with sapwood‐specific hydraulic conductivity, mass‐based net assimilation rate, stomatal conductance (gs), intercellular CO2 concentration (Ci) and the petiole vessel lumen diameters (Dv), but positively correlated with wood density. Pit morphology was only negatively correlated with sapwood‐ and leaf‐specific hydraulic conductivity and Dv. Pit density was positively correlated with gs, Ci and Dv, but negatively with intrinsic leaf water‐use efficiency. Pit and pit aperture shape were not significantly correlated with any of the physiological traits. These findings indicate a significant role of pit characteristics in xylem water transport, carbon assimilation and ecophysiological adaptation of Ficus species in tropical rain forests.
The SER Standards, cultural ecosystems, and the nature‐culture nexus—a reply to Evans and Davis
Authors: McDonald Tein , Aronson James , Eisenberg Cristina , Gann George D. , Dixon Kingsley W. , Hallett James G.
Published: January 2019

Evans and Davis claim the SER Standards use a “pure naturalness” model for restoration baselines and exclude most cultural ecosystems from the ecological restoration paradigm. The SER Standards do neither. The SER Standards consider both “natural” ecosystems (that are unequivocally not cultural) and “similar” cultural ecosystems as suitable reference models. Furthermore, Evans and Davis propose assessing whether a cultural ecosystem exhibits “good, bad, or neutral impacts from humans on ecosystems” as the basis for reference models. We argue that such an approach would overlook the indispensability of native ecosystem benchmarks to measure human impacts and provide a springboard for social‐ecological restoration.
Restoration potential of invaded abandoned agricultural fields: what does the seed bank tell us?
Authors: Haussmann Natalie S. , Delport Christopher , Kakembo Vincent , Mashiane Katlego K. , le Roux Peter C.
Published: January 2019

Soil seed banks can play an important role in the restoration of degraded ecosystems, especially where indigenous species are well represented in, and invasive species are largely absent from, the seed bank. Here, we studied the potential contribution of the soil seed bank to the restoration of invaded, abandoned agricultural fields in the Eastern Cape, South Africa. We recorded the aboveground cover and belowground abundance of all vascular plant species from 120 quadrats that differ in cover of the extralimital woody invader, Pteronia incana. Our results show that higher cover of P. incana is associated with lower species richness, aboveground cover, and belowground seed abundance. Furthermore, community similarity between the above‐ and belowground component was low, with the seed bank and standing vegetation having only 15 species in common and 49 species being recorded only from the seed bank. We suggest that this large number of seed bank‐only species is a relic of previous vegetation, prior to large‐scale invasion by P. incana. The most important finding from our study is the absence of P. incana from the soil seed bank. This finding, combined with the large number of mostly native species from the seed bank, holds promise from a restoration perspective. However, given the susceptibility of the invaded systems to erosion, coupled with the low grazing value of the seed bank species, we suggest that P. incana removal should be accompanied by both erosion control measures and reseeding with palatable grass species, to secure the livelihoods of local communities.
The Big Five and Southern Legislative Distinctiveness
Authors: Turner Joel F. , Kash Jeffrey P. , Lasley Scott
Published: January 2019

Objective

Previous research has found that southern state legislators demonstrate more progressive ambition than their nonsouthern counterparts. This presents an interesting puzzle with regard to why this difference exists. In this article, we apply the Five‐Factor Model (conscientiousness, agreeableness, neuroticism, openness, and extraversion) to investigate whether regional personality differences exist that can help explain why southern legislators exhibit greater levels of progressive ambition than nonsouthern legislators.

Methods

Data from a national survey of state legislator are analyzed using ordinal regression.

Results

Our findings show that higher levels of extraversion and openness among the legislators are directly related to greater levels of political ambition. More specifically, southern legislators appear to possess disproportionately higher levels of extraversion and openness than their nonsouthern counterparts. This helps explain the greater levels of progressive ambition they express.

Conclusions

In addition to providing insight into progressive ambition, the results reinforce the notion of southern distinctiveness among state legislatures.
D‐Licensing in Adjectival Passives
Authors: Hallman Peter
Published: January 2019

This article argues that in addition to the familiar Case licensing requirement known as the ‘Case Filter’, nominal arguments (DPs) are subject to a requirement that I refer to as ‘D‐licensing’, construed as a requirement of DPs themselves. It is claimed that this notion of D‐licensing is useful in the characterization of restrictions on adjectival participle formation. Adjectival participles fail to license the full complement frame of the corresponding verb not because they fail to assign Case, but because they lack D‐licensing structure.
Ambiguous Labeling and Full Interpretation
Authors: Mizuguchi Manabu
Published: January 2019

Syntactic objects constructed by Merge are label‐less and are identified or labeled by a labeling algorithm called Label for interpretation at the interfaces. It has been argued that the set of the form {{XP}, {YP}} (or simply,XP‐YP) incurs labeling ambiguity and cannot be labeled unless [i] eitherXPorYPmoves out or [ii] X and Y agree. This paper considers labeling ofXP‐YPand argues that labeling ambiguity can be tolerated, causing no labeling failure. I claim thatXP‐YPcan be labeled either 〈X〉 or 〈Y〉, which is a natural consequence of minimal computation. The well‐formedness of labeling is attributable to theCIinterface (or conditions imposed by theCIsystem), with syntax not caring about the outcome of labeling. I show that ambiguous labeling is empirically supported and removes unwanted stipulations on labeling.
Clinical analysis and nonsurgical management of 11 dogs with aural cholesteatoma
Authors: Imai Akihiro , Kondo Hirotaka , Suganuma Tsunenori , Nagata Masahiko
Published: January 2019

Background

Aural cholesteatomas, also called tympanokeratomas, are destructive and expansile growths of keratinizing epithelium that develop in the middle ear. They have been reported sporadically in dogs, and surgery is usually the recommended treatment.

Objectives

To describe the common clinical, radiological and histological findings of cholesteatoma; to report on the outcome of conservative management.

Animals

Eleven dogs (13 ears) with cholesteatomas.

Methods and materials

Medical records were reviewed for dogs diagnosed with cholesteatoma between 2012 and 2018. All dogs had computed tomography (CT) and/or magnetic resonance imaging (MRI) followed by trans‐canal endoscopic procedure (TEP) for removal and biopsy of middle ear lesions. Dogs were then treated with in‐clinic flushing initially weekly tapered to monthly, as well as at‐home ear cleaning and application of topical otic steroid medication, initially daily then tapered to once or twice weekly.

Results

Nine dogs had a history of chronic otitis externa; head tilt or facial paralysis was present in seven and four cases, respectively. Otic examination identified a protruding nodule in seven ears.CTdemonstrated soft tissue‐like material in 12 bullae and expansion in seven bullae.MRIrevealed minimally contrast‐enhancing bulla contents in 12 ears. Post‐TEPand with maintenance medical treatment, nine ears had no further signs of middle ear disease during a mean follow‐up of 27.9 months.

Conclusions and clinical importance

The results suggest that otitis externa may not necessarily precede cholesteatoma in all dogs.MRIappears to be more sensitive thanCTfor identifying cholesteatomas. Conservative treatment of cholesteatomas could be useful before or as an alternative to surgery.
Adaptation and evaluation of a monopolar electrosurgical triangle‐tip knife for transendoscopic ventriculocordectomy in healthy horses
Authors: Suarez‐Fuentes David G. , Tatarniuk Dane M. , Caston Stephanie S. , Bell Chris D. , Loinaz Ricardo J. , Hostetter Jesse M.
Published: January 2019

Objective

To evaluate the efficacy and safety of a transendoscopic monopolar electrosurgical triangle‐tip knife as instrumentation to perform unilateral ventriculocordectomy (VC) in healthy adult horses.

Study design

In vivo experimental study.

Study population

Nine horses donated for medical conditions unrelated to respiratory system.

Methods

The triangle‐tip knife was applied in contact fashion. Left VC was performed under standing sedation. Endoscopic images of the upper airway were graded for inflammation by 2 masked surgeons preoperatively and immediately, 24 hours and, in 2 cases, 7 and 14 days postoperatively. Four larynxes were examined for histological evidence of inflammation and collagen deposition at 24 hours (n = 2) and at 14 days (n = 2) after surgery.

Results

Ventriculocordectomy was successfully performed in all horses. Endoscopic evidence of inflammation was scored as normal (preoperatively), mild (immediately postoperatively), mild (24 hours postoperatively), mild (7 days postoperatively), and normal (14 days postoperatively). According to histopathology, inflammation of the surgical site and ventricularis muscle was generally increased (variable is common and is present in most high‐power fields) 24 hours and 14 days postoperatively. Fibrosis and collagen deposition also seemed increased at the surgical site 14 days postoperatively.

Conclusion

Ventriculocordectomy was successfully performed with an electrosurgical triangle‐tip knife and resulted in acceptable short‐term outcomes.

Clinical significance

The use of an electrosurgical triangle‐tip knife alternative instrumentation may be offer an alternative option to perform VC in practices when diode laser is not available or is cost prohibitive. Longer term evaluation of the VC site is required to determine the effect on rima glottic cross‐sectional area.
A Methodology for Evaluating the Adoption of Knowledge and Innovation Management Tools in a Product Development Process
Authors: Bordegoni Monica , Cascini Gaetano , Filippi Stefano , Mandorli Ferruccio
Published: January 2019

The efforts made by a company to focus on the manufacturing process to minimize production costs are not any more sufficient to launch competitive products on the market. In recent years, the industry has focused on the integration and optimization of the phases of the product development process and on the introduction of innovations in the attempt to tackle and solve the above mentioned issues. The paper presents the results of a research project whose aim is to study a methodology for the evaluation of the impact and costs related to the adoption of new and innovative technologies for knowledge and innovation management within currently implemented companies’ product development processes (As-Is process).
Design Through Common Graph Representations
Authors: Shai Offer
Published: January 2019

Current paper introduces a new technique that enables to solve design problems through their discrete mathematical models called – graph representations. When different engineering fields are represented by the same (common) graph representation, channels for knowledge transformation are paved between these fields. Current paper employs these knowledge transformation channels for design, by transforming a design problem into a design problem in another (secondary) engineering domain. Then, a search is performed in the secondary domain for existent solution. Once such solution is found, it is transformed back to the original domain through the same graph representation based channel. The paper provides a thorough design case study demonstrating the idea behind the proposed technique.
A Design Data Model to Support Rationale Capture and Functional Synthesis
Authors: Aurisicchio Marco , Bracewell Rob H. , Walllace Ken M.
Published: January 2019

Keeping design notebooks is widely considered to be a very good practice as it allows the progression of a design to be recorded, and it is one of the few spontaneous ways in which designers document their design processes. Nevertheless, design notebooks by their nature contain diverse collections of information and knowledge, lacking any clear and comprehensive structure. The aim of researching the generation and use of such design knowledge is to provide a better understanding of how it may be captured and structured for later review and reuse, either by the original designers or by others. In this paper, we explore and test ways of structuring design rationale that is recorded in design notebooks during mechanical design projects. Our investigation focuses on the application of two well-known alternative knowledge structures. These are PROSUS matrices that are used for indexing design rationale against the nodes of a product breakdown [1], and Function-Means Trees [2] that are used to represent the generation and combination of alternative partial design solutions. The results are compared with the Design Data Model, which has been proposed as a way of beneficially unifying these two seemingly incompatible approaches. Design notebooks kept during the Mobile Arm Support project, an inhouse design project undertaken between 1992 and 1997 in Cambridge Engineering Design Centre, provided the source material to illustrate our arguments.
On Rank Reversals in the Borda Count
Authors: Scott Michael J. , Zivkovic Irena
Published: January 2019

The Borda count is a pairwise comparison method which can be shown to have various desirable properties. Questions have been raised about the efficacy of the Borda count and its engineering equivalents for concept selection in engineering design. Of chief concern is the possibility of rank reversals among design alternatives when other alternatives are added or dropped from consideration. Results from simulations are presented that show the likelihood that Borda count comparisons will result in rank reversals upon modifications of the set of alternatives. The available evidence indicates that rank reversals in the Borda count are generally restricted to alternatives that are difficult to distinguish.
Platform Commonization With Discrete Design Spaces: Introduction of the Flow Design Space
Authors: Corbett Brian P. , Rosen David W.
Published: January 2019

Many companies have adopted the usage of common platforms to support the development of product families. The problem addressed in this paper deals with the development of a common platform for an existing set of products that may or may not already form a product family. The common platform embodies the core function, form, and technology base shared across the product family. In this work, we focus on configuration aspects of the platform commonization problem to determine which components are in the platform and the relationships among these components. Configuration design spaces are discrete and combinatorial in nature, but not necessarily purely combinatorial, as certain combinations represent infeasible designs. By carefully forming discrete design spaces and applying constraints to them, feasible design regions can be found and their sizes predicted. The purpose of this paper is to outline our approach to defining configuration design spaces for engineering design, with an emphasis on the mathematics of the spaces and their combinations into larger spaces that more completely capture design requirements. A new design space that models flows among components is introduced. Other design spaces that model physical connectivity, functionality, and assembly considerations are summarized. An example of a family of rechargeable flashlights illustrates the application of the discrete design space approach to develop a common platform.
Work Structure Based Collaborative Engineering Design
Authors: Zhao Li , Jin Yan
Published: January 2019

Collaborative engineering design requires multiple people working together to achieve a common goal. Data sharing approach and workflow management approach have been developed to support collaborative design, but the disconnection of these two approaches has led to problems of efficiency and adaptability. In this paper, we propose a work structure based approach for collaborative design. Our goal is to improve process efficiency and adaptability by integrating management processes with engineering details and allowing designers to make certain managerial decisions through peer coordination. For a specific task, a work structure is a network of engineering work items connected by dynamically acquired engineering dependencies. It is used to generate multiple processes from which the one that best fits the current situation is dynamically determined through coordination among team participants. In order to capture engineering dependencies and associate engineering details, an adaptive work process model is developed that explicitly represents engineering work, work structure, and processes. Based on this model, a set of operations and algorithms are developed for intelligent agents to provide coordination support. Experiments have shown that by following this approach, engineering design processes can dynamically adapt to both requirement and resource changes, and the process efficiency can be significantly improved.
Pump Replacement at a Critical 63 Year Old Pump Station
Authors: Greaves Thomas H.
Published: January 2019

The pump station at Kinder Morgan Canada’s (KMC) Kamloops facility has been in operation for 60+ years. In that time the four parallel pumps in the facility have each moved an estimated 1 billion barrels of crude oil, gasoline and diesel from the Sherwood Park area of Alberta and the oil fields of NE British Columbia to the west coast of Canada and into Washington State.

This paper describes the innovative project (see Figure 1 above) where the four existing multi-stage parallel pumps at the Kamloops facility were replaced with two single stage series pumps.

This paper assumes the reader has a working knowledge of pump hydraulics.

A detailed list of all acronyms used within this paper is located at the end of the document under the heading entitled “Nomenclature”.
Ensuring Pipeline Risk Model Usability
Authors: Alfano Tony , Weichel Megan
Published: January 2019

Equally important to choosing the correct pipeline risk modeling approach is ensuring the identified risks are properly managed through a fully integrated risk management program. Implementing the most sophisticated risk modeling algorithm on the market will not help a company manage their risks if the model and associated program are not usable to the company. The role of a framework is to provide specific guidance to support other company programs by referencing applicable management system elements and outlining additional elements specific to the program itself. A successful risk management framework sets the groundwork for effective risk management by ensuring the risk management program is integrated into the company in a way in which all relevant stakeholders benefit from its use.

This paper outlines common pipeline risk management framework elements and their links to the Pipeline Safety Management System elements set forth in API RP 1173. As the development of such a framework is often an iterative process, prioritized aspects are identified for companies undertaking the development of such a system.
‘We’re Still Hitting Things’: The Effectiveness of Third Party Processes for Pipeline Strike Prevention
Authors: McDermott Vanessa , Hayes Jan
Published: January 2019

High-pressure gas pipelines are vulnerable to damage in the course of building or maintaining other infrastructure, such as roads, water pipelines, electricity or telecommunications cabling. Unlike other countries, there has never been a death or serious injury from a high-pressure gas pipeline strike in Australia and yet external interference continues to be the most common cause of pipeline damage despite a range of technical and legislative measures in place. This research project aims to enhance the safety strategies regarding third party pipeline strikes by giving the pipeline sector a greater understanding of the motivations and priorities of those who work around pipeline assets and so how to work with them to achieve better outcomes.

Using data gathered from more than 70 in-depth interviews, we explore empirically alternate understandings of risk amongst a range of stakeholders and individuals that are responsible in some way for work near or around high-pressure gas transmission pipelines in Australia. Outside the pipeline sector, much of the work around pipelines is conducted by those at the bottom of long chains of contractors and sub-contractors. We discuss perceptions of risk held by a range of third party actors whose activities have the potential to threaten gas pipeline integrity. We compare these views with gas pipeline industry perceptions of risk, couched in terms of asset management, public safety, legal and insurance obligations, and reputation management.

This paper focuses on how financial risk and so also management of the potential for pipeline strikes is shifted down the third party contractor chain. Added to this, incentives for timely project completion can unintentionally lead to situations where the potential for third party contractors to strike pipelines increases. The data shows that third party contractors feel the time and cost impact of design or project changes most immediately. Consequently, strikes or near misses may result as sub-contractors seek to avoid perceived ‘unnecessary’ time delays along with the associated financial impact. We argue that efforts to reduce the potential for pipeline strike need to be targeted at structural changes, rather than simply aimed at worker risk perception and enforcement of safety compliance strategies.
Current Land and Waterborne Geophysical Methods for Guiding Horizontal Directional Drilling and Trenching Along Pipeline Right-of-Ways
Authors: Bauman Paul , McClymont Alastair , Woods Landon , Ernst Erin
Published: January 2019

In Western Canada, oil and natural gas pipeline projects are being considered that will move hydrocarbons from the Prairie Provinces and British Columbia, to the Pacific Ocean, the Atlantic, and even potentially the Arctic. Along the proposed right-of-ways, the pipeline engineers will encounter challenging and varied terrain, including discontinuous permafrost, creek and river crossings, glaciomarine clays, thick muskeg, and other subsurface conditions that require specialized engineering planning in advance of construction. Geophysical surveys, in support of geotechnical investigations, provide continuous subsurface information to help inform design challenges associated with the many terrain challenges. Some geophysical surveys to be considered include electrical resistivity tomography (ERT), induced polarization (IP), seismic refraction, seismic reflection, multi-channel analysis of surface waves (MASW), ground penetrating radar (GPR), and borehole geophysics. Typically, a combination of several geophysical surveys along with drilling information, are optimal for the cost-effective site characterization of problematic segments of proposed pipeline right-of-ways.
Some Observations on Soil-Pipe Interface Shear Strength in Direct Shear Under Low Effective Normal Stresses and Large Displacements
Authors: Amarasinghe Ruslan S. , Wijewickreme Dharma , Eid Hisham T.
Published: January 2019

Experimental work is undertaken at the University of British Columbia (UBC) to study the soil-pipe interface shear strength at levels of shear displacements and effective normal stresses typically encountered in offshore soil-pipe interaction problems. A macro-scale interface direct shear apparatus having a test specimen footprint of 1.72 m × 1.75 m was designed and built for this purpose. The apparatus is capable of testing various soil-pipe interfaces under effective normal stresses in the range of 3 kPa to 6 kPa. A maximum shear displacement of 1.2 m is achievable at rates ranging from 0.1 μm/s to 1 mm/s. Sensors mounted at the interface enable the accurate determination of the effective normal stress at the interface when fully saturated fine-grained soils are tested. This paper presents some observations arising from a series of interface direct shear tests involving fine-grained soils of different plasticity against bare and epoxy coated steel surfaces.
Integrity of Small Angle Mitered Joints
Authors: Zheng Gavin (Guowei) , Colquhoun Iain , Paviglianiti Joe
Published: January 2019

Miter bends are permitted for use in the oil and gas industry in a variety of configurations. This paper addresses small angle miter joints used to correct minor misalignments.

The CSA Z662-15 standard (Oil and Gas Pipeline Systems) states in the construction section (Clause 6.2.3(g)) that “mitred bends shall not be used”. However, a note accompanying the clause states that “deflections up to 3 degrees caused by misalignment are not considered to be mitred bends.” Nonetheless, concerns continue to be raised that stresses introduced due to this misalignment can affect safety and operation of pipelines.

This paper reviews literature of failures associated with mitered joints and the theoretical development of stresses in miters, and presents results from a linearized sensitivity analysis of buried mitered joints under pressure and thermal loading based on ASME B31.1 and B31.3 criteria. The paper contains an analysis of the origins of CSA-Z662 Clause 6.2.3(g). Recognizing that the stresses introduced by miters are discontinuity stresses, the paper discusses the effects of such stresses, including the use of miters in cyclic service.

Recognizing also the strong dependence of D/t ratio on the discontinuity stress, the paper suggests a modification to the Z662 approach to account for this effect. This modification would provide guidance to the use of miters to effect small deflections both during design and construction of piping.
Use of Bowties for Pipeline Safety Management
Authors: Pettitt Glenn , Pennicott Philip
Published: January 2019

Bowtie diagrams have become a widely-used method for demonstrating the relationship between the causes and consequences of hazardous events following the identification of Major Accident Hazards (MAHs). They are particularly useful for illustrating how safeguarding measures protect against particular threats or mitigate the various consequences of an incident. Bowtie diagrams have been widely used in a range of industries for over twenty years and are widespread in the upstream oil and gas industry, as well as other high hazard industries such as mining and nuclear.

Bowtie diagrams are used for a range of purposes. At their simplest, they provide an overview of the measures in place to prevent and mitigate hazardous events, and as such are valuable additions to training programmes. A bowtie diagram provides an excellent platform to show regulatory authorities, trainees and new employees the various threats to a pipeline system, and what barriers are in place to prevent and control major accidents, such that the risks are as low as reasonably practicable.

The bowtie process may be used during design, construction, operations and decommissioning. The bowtie for construction is different to that for design and operations, being more to do with occupational safety rather that loss of containment. However, the construction bowtie diagram still plays a vital role in minimising risk.

Whilst the typical failure mechanisms for pipelines are generally well-established during operations, bowties have a key role in informing senior management of the measures in place to reduce risk. Furthermore, a large proportion of major accidents may occur at above ground installations (AGIs), and bowtie diagrams provide a mechanism to help management in the protection of personnel and potentially of nearby populations. For both cross-country pipelines and AGIs, the effectiveness of each barrier can be established to ensure that the risk of loss of containment is minimised.

More detailed bowties may be used to assist in identifying safety critical elements (SCEs) or safety critical tasks; developing performance standards and defining process safety performance indicators. Often, the hardware shown by the barriers may be considered as SCEs, particularly in the case of effective barriers, such as vibration detection along the right-of-way (RoW) (prevention) or gas detection at AGIs (recovery). Where such barriers are defined as key to a major threat, the bowtie diagram illustrates the importance of good maintenance systems to ensure that the barriers have a high reliability. Thus, by defining the SCEs in a logical manner, bowties may be a key element in managing the risk from a pipeline system.
Safety Level on Different Offshore Pipeline Design Criteria: A Comparison Between DNV-OS-F101 and API RP-1111 Codes
Authors: D’Angelo Luis , Thorsen Hans M. , Fyrileiv Olav , Collberg Leif , Furtado Sonia
Published: January 2019

Submarine pipelines are more often than before required to operate in harsh environments, especially for systems deployed in ultra-deep water. In order to minimize the installation tension due to the hanged section, they are installed empty and therefore the external pressure is often the prime load parameter for the design.

New discoveries and associated technical challenges have generated important research and development endeavors in a wide range of disciplines in order to improve efficiency and reliability, but also keeping the risks associated with the new scenarios within an acceptable range. Some aspects that can be mentioned include, for instance, steel line grade improvements and manufacturing innovations of pipe products; more powerful lay vessels and development of new pipeline installation methods; determination of the mechanical behavior and the expected failure modes of concern for deep and long pipelines under combined loads; and the improved different design criteria like the DNV-OS-F101 (1) and API RP-1111 (2) codes.

The intention of this paper is to review and compare three different pipeline design criteria well established in the oil and gas industry. The pipeline wall thickness design for pipe pressure containment (bursting), local buckling (system collapse) and propagating buckling for DNV-OS-F101 (1) and API RP-1111 (2) are discussed as well as the parameters used, definitions, safety philosophy and code limitations. A pipeline example is used to illustrate and compare the results.
Re-Introducing the Benefits of Terrain Mapping for Pipeline Routing and Design
Authors: Johnston Katherine , Waddington Betsy , Leir Mark , Kenny Corey
Published: January 2019

Terrain mapping is the process of the interpretation of aerial photographs, LiDAR and satellite imagery plus field based ground truthing to delineate and characterize terrain polygons with similar surficial materials, landforms and geological processes [1]. For new pipeline projects, detailed terrain mapping is usually completed at a map scale of 1:20,000 corresponding to ground accuracy, at best, of 20 m. Although typically used to support the forestry industry in planning and developing forestry operations in British Columbia, Canada [2], and despite the rapid advancements of remote sensing technology, the art and science of terrain mapping continues to be an essential. albeit somewhat forgotten, tool for new and existing pipeline projects in a variety of terrain settings.

For new pipeline projects, a quality terrain mapping product has been be used to characterize ground conditions and support the estimation of design inputs for numerous aspects of pipeline routing and design [3,4]. It is the backbone of most terrain and geohazard related tasks on a pipeline project and it is useful through many stages of a project’s development [5]. At routing and feasibility stages of a project, terrain mapping can be used to efficiently identify geohazards to avoid and to allow comparison of the terrain between different corridor options. Later on at the early design stages, terrain mapping can be used to develop and maintain a geohazard inventory to support geohazard risk assessment and design through geohazards that could not be avoided [6], delineate areas of shallow groundwater where buoyancy control and construction dewatering maybe required, help estimate soil spring parameters to support pipe stress analysis, delineate areas of shallow bedrock to support construction cost estimates and planning [8], and to identify sources of sands and gravels that maybe used for pipeline construction.

This paper is intended to re-introduce the ongoing benefits of terrain mapping for new pipeline projects and describe how terrain mapping can cost-effectively support a pipeline project through its lifecycle of feasibility, design, and construction. Examples of the benefits of terrain mapping for routing and design of two proposed transmission pipelines in northern BC are presented. This work will be of interest to project managers, engineers, scientists and regulators involved with routing, design, and construction of new pipelines projects.
Simulation of Gas-Hydrate Slurry Stratified Flow With Inward and Outward Hydrate Growth Model
Authors: Shi Bohui , Liu Yang , Ding Lin , Lv Xiaofang , Gong Jing
Published: January 2019

The topic of hydrate formation and blocking in offshore petroleum industry has attracted more and more attentions, which is known as one of the flow assurance issues. A new technology has been proposed to avoid the occurrence of hydrate blockage in multiphase transportation system, which is hydrate slurry flow technology, also named as cold flow technology. The low dosage hydrate inhibitor of anti-agglomerate was added into the flow systems to allow hydrate formation in the liquid phase while it prevented the aggregation of hydrate particles. Thus these particles were evacuated with the liquid phase as pseudo-fluid like slurry. In this work, an inward and outward hydrate growth shell model coupled with two phase flow hydrodynamic model was applied to investigate the characteristics of gas-hydrate slurry stratified flow. The inward and outward hydrate growth shell model considered the kinetics, mass transfer and heat transfer process of hydrate formation, which could predict the hydrate formation rate and the released heat. The two phase flow hydrodynamic model included mass, momentum and energy equations. A case for an inclined pipeline was simulated using the combined models. The results showed that once the kinetic requirements for hydrate crystallization was satisfied, hydrates would form quickly at the initial stage and then hydrate formation rate would decrease obviously due to the limitation of mass transfer and heat transfer. Meanwhile, the flow characteristics, such as the liquid holdup and pressure drop, were predicted by the model, which also provided an acceptable results about the state of hydrates (onset time of formation, formation rate, volume fraction, etc.) in multiphase system for the operation engineers in the field. The key parameters of the inward and outward hydrate growth shell model were determined by referring to the literatures. To investigate the reliability and influence of these set values on the results, a sensitivity analysis of the key parameters of the shell model was implemented. Further works should be done, such as the flow mechanism in other flow regimes as well as the influence of particle aggregation.
Effect of Calibration of Measurements on Integrity Reliability Analysis
Authors: Cheng Karmun , Abdolrazaghi Mona , Hassanien Sherif , Watt Charles
Published: January 2019

The emphasis on pipeline safety through reliability analysis strategies in the pipeline industry has pushed the process of uncertainty quantification towards advanced statistical techniques. Probabilistic modeling of pipeline threats and inline inspection (ILI) validation/tool performance assessment are areas that have all benefited from advances in uncertainty quantification. More recently, the statistical calibration of measurement uncertainty has developed as a promising approach for reducing the effect of measurement errors that exist in both ILI and field non-destructive examination (NDE) measurement readings. Using traditional methods for estimating measurement error quantities in ILI data, calibration provides a robust and simple approach towards incorporating the error information towards obtaining an improved estimate of the true value. Since calibration is performed at the individual feature-level, its combination with probabilistic modeling using statistical distributions at the parameter-level can potentially provide an opportunity to understand its effect on the probabilistic analysis (leak or burst limit state). In this work, the impact of applying statistical calibration towards identifying/utilizing ILI and NDE measurement uncertainty in conjunction with probabilistic modelling is explored through an investigated problem.
Training and Education: The Great Competence Divide...
Authors: Unger Michelle , Hopkins Phil
Published: January 2019

All industries need ‘competent’ staff, and pipeline standards and regulations expect all staff in the pipeline industry to be competent. This is emphasized by a North American pipeline regulator stating in its report on a failure: ...the management of training and competency is particularly critical for an organization [operating pipelines]’.

Competence is a mix of skills, knowledge, and experience, and is obtained from training, mentoring, and experience. Consequently, industry knows how to develop competencies, but how can companies prove their staff are competent? Staff can attend the many training courses on offer, but how can the industry know these courses are the required quality, and that staff have acquired and absorbed the necessary skills/training?

This evidence and demonstration are major problems in the pipeline industry, and need urgent solutions. Fortunately, the industry can learn from academia, who have been providing demonstrable skills for centuries.

Most current industry training courses are presented by good trainers, using good materials, through good training providers. Unfortunately, most of these courses/trainers/organisers are not accredited by any reputable organisation, the materials are not quality assured, the necessary competence levels are neither specified nor defined, and there is no assessment to demonstrate understanding. This learning process may be good and delivered in good faith, but it is disorganised, unregulated, with no control or benchmarking, and no assessment. This leads to a lack of credibility.

Academia has a well-established, but relatively simple system to ensure its learning process is credible. It has: courses that are assessed to a specified learning level, with clear objectives, outcomes, and qualification requirements; materials that are independently quality assured; lecturers that are qualified to teach; and, an assessment, qualification, and certification process that demonstrates the student has acquired all the stated skills. This leads to credibility.

This paper assesses current training in the pipeline industry, and highlights the good points and bad points, and the deficiencies in the learning process, that prevent demonstrable competencies. It then describes how academia has a rigorous learning process that allows this demonstration.

The paper ends with a ‘way forward’ for the pipeline industry, in its goal of demonstrating competency in its workforce.
Application of the Discrete Element Method (DEM) to Evaluate Pipeline Response to Slope Movement
Authors: Fredj Abdelfettah , Dinovitzer Aaron , Hassannejadasl Amir , Gailing Richard , Sen Millan
Published: January 2019

The long linear nature of buried pipelines results in the risk of interaction with a range of geotechnical hazards including active slopes and land surface subsidence areas. Ground movement induced by these geotechnical hazards can subject a pipeline to axial, lateral flexural, and vertical flexural loading. The techniques to predict pipeline displacements, loads, stresses or strains are not well described in design standards or codes of practice. The results of geotechnical site observation, successive in-line inspection or pipeline instrumentation are used to infer pipeline displacement or strain accumulation and these techniques are often augmented through the application of finite element analysis. The practice of using finite element analysis for pipe-soil interaction has developed in recent years and is proving to be a useful tool in evaluating the pipeline behavior in response to ground movement.

This paper considers pipeline response to geotechnical hazard-induced loading scenarios related to slope movement transverse to the pipeline axis. The details of the three-dimensional LS-DYNA-based BMT pipe-soil interaction model employing a discrete element method (DEM) are presented in this paper. The validation of the numerical models through comparison with medium-scale physical pipe-soil interaction tests are described to demonstrate that the models are capable of accurately simulating real world events. The models are further calibrated for nominal soil types to replicate the pipe-soil load displacement properties outlined in ASCE guideline recommendations by developing responses that closely agree with these results from the physical trials and engineering judgement.

The utility of advanced pipe-soil interaction modelling in supporting strain-based pipeline integrity management or design is demonstrated by presenting the results of geotechnical hazard numerical simulations. These simulations are used to describe the sensitivity of pipeline displacements and strains to the demands of these geotechnical events and develop relationships between the geotechnical event key parameters and pipeline response.