bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heavy Wall Bends for Sour and Arctic-Alike Environment
Authors: Farè Stefano , Bagliani Emanuele Paravicini , Crippa Stefano , Zana Fabio , Darcis Philippe 
Published: October 2015

During last decade, customers’ requirements of Line Pipes and accessories became more and more stringent. This process is led by the exploitation of fields with more severe conditions of pressure, environment and temperature. For this reason, heavy wall products (both straight pipes and bends) need to be developed.
A development program was carried out in order to satisfy more stringent requirements and higher wall thickness. The metallurgical approach to steel design aimed to improve the combination of strength and toughness and increase the control of hardness after quenching and tempering, preserving adequate weldability.
Industrial trials were performed to manufacture 60 mm thick hot induction bends in grade X65. Characterization was carried out after various post bending heat treatments (quenching, tempering and post welding).
The new low-C steel showed promising results. The full characterization of off-line Q&T bends at various locations (tangent length, transition zone, and bend body) confirmed the achievement of X65 grade, with hardness HV10 < 240, Charpy V-notch transition temperature < −60°C, Crack Tip Opening Displacement > 0.7 mm at −45 °C, and very good HIC and SSC resistance.
Short-Term Operational Sea Ice Forecasting for Arctic Shipping
Authors: Howell Carl , Richard Martin , Barnes Joshua , King Tony 
Published: October 2015

The Arctic sea ice is declining in extent, volume and thickness. With this decline comes an increased interest in the two main Arctic shipping routes: Canada’s Northwest Passage (NWP) and Russian Northern Sea Route (NSR). The NWP is the most direct route between Asia and the East coast of North America. Some routes are up to 40% shorter than those using the Suez Canal.
With commercial and contractual implications, Arctic shipping route access needs to be predictable with sufficient lead time to allow optimization. This paper presents a methodology for forecasting the timing and length of the open-water season (by determining freeze-up and break-up dates) on regional scales at key locations in the NWP along with examples of applications.
A suite of statistical models were developed to forecast the timing and length of the open-water season at key locations within the NWP, using a multi-node based quadratic discriminant (QD) approach. Forecasts are feasible up to four weeks in advance. Ensembles of QD models were built for key regions using a feature selection method to select an optimized set of input parameters to better discriminate between two states (i.e., ice or open-water). The set of available features used included observed and modeled environmental, oceanographic and atmospheric parameters. Results of models with a 28-day forecast horizon show that over 59% of predictions for break-up and 79% of predictions for freeze-up fall within a ±4-day range, which is the error on the reference dates derived from the weekly CIS ice charts.
Assessment of Pipeline Walking With Coupled Triggering Mechanisms by Finite Element Approach
Authors: Birdas Michail , Srinil Narakorn , Van den Abeele Filip 
Published: October 2015

Asymmetric loading/unloading profiles during the start-up and shut-down operations of high pressure high temperature pipelines may cause an accumulated axial displacement over several operational cycles known as Pipeline Walking phenomenon. This pipeline walking can be triggered by several factors e.g. the seabed slope, riser tension and thermal transients. Several studies have been carried out in the literature regarding the influence from individual factors; nevertheless, very little has been made in the evaluation of coupled triggering mechanisms, common for a pipeline segment.
This paper investigates the pipeline walking phenomenon using finite element modelling and analysis software SAGE Profile 3D versus standard analytical formulae. The keys aims are (i) to study the interaction and coupling between the walking triggering mechanisms by comparing coupled and uncoupled analyses, and (ii) to compare the obtained numerical results with analytical predictions, commonly used in the subsea industry. Depending on the pipeline and soil properties, the effect of triggering mechanisms is parametrically investigated with varying pipeline tension and seabed slope for a specific thermal gradient profile.
It is found that the common approach to sum up the individual walking rate by the uncoupled analysis for a combination of any two triggering mechanisms, underestimates the walking phenomenon when compared with the coupled analysis. This highlights how attention must be paid to the interaction mechanism. In addition, this study emphasizes that the analytical models severely overestimate the pipeline walking phenomenon, especially when more than one triggering mechanisms are present.
Validation of a Software Tool (DROPSIM) to Predict the ‘Drop and Getaway’ Behaviour of a Lifeboat
Authors: Palermo Elia , Tonelli Roberto , Quadvlieg Frans , Scharnke Jule , Drummen Ingo , Teigen Per 
Published: October 2015

The purpose of a free fall lifeboat is to evacuate people from platforms in case of emergency, and when other, normal means of evacuation, are not possible. For instance, when the weather is too rough, and evacuation cannot be performed by helicopters, the lifeboats are the last way of escape. It is thus essential to be able to properly assess the operability of a lifeboat and the safety of its occupants upon evacuation.
Over the past four years, methods to quantify the operability limits of a lifeboat were analysed in a research project carried out for Statoil. As part of this project, a prototype software (denominated DROPSIM) was developed to predict the ‘drop and sailaway behaviour’ of a lifeboat. DROPSIM is a simplified method based on strip theory, with the objective to obtain predictions that are consistent with the relevant statistical behaviour of the lifeboat, and for the same target level of probability.
Particularly because DROPSIM is a simplified tool, it is vital to verify that the software is adequate for simulating thousands of random lifeboat drops, yielding robust statistical predictions with sufficient accuracy. In order to show the performance of the simulation tool, an extensive validation procedure was established, based on a large amount of model test and data from other simulation tools. The following topics were considered in the validation:
A. Verification: basic checks, e.g. related to buoyancy without comparison to model tests
B. Consistency of simulated and measured response for basic test cases, including free-falling wedge tests and a variety of impact tests with a bullet shaped model
C. Prediction of the sailaway behaviour of a lifeboat in comparison to model tests
D. Comparison with integrated drop and sailaway model tests in normal and off-design (extreme) conditions in calm water and in waves.
In this paper the results of the validation of DROPSIM are presented and discussed. Another dedicated paper gives insight into the mathematical model of DROPSIM ([1]).
Modelling of Sea Storms Associated With Energy Harvesters: Downtime and Energy Losses
Authors: Arena Felice , Laface Valentina , Malara Giovanni , Romolo Alessandra 
Published: October 2015

The design of an energy harvester involves achieving the two following objectives: to install a safe structure with a reasonable safety margin; and to install an effective device which is able to capture energy in a variety of environmental conditions. In this context, the long-term modelling of the environmental variables plays a crucial role.
In the context of wave energy harvesters, the occurrence of sea storms is a critical element in the design process. Indeed, its identification is required for determining extreme loads as well as controlled de-activations of the device for preserving the mechanical components into the device.
Considering these issues, the paper proposes an analysis of the wave climate oriented to the determination of the downtime and of the energy losses. Specifically, the paper provides expressions: for calculating the average deactivation time of a wave energy device, given that it must be deactivated if the significant wave height is larger than a certain threshold; and for calculating the energy “lost” (as it is not absorbed by the device) during a storm in which the maximum wave height is larger than the mentioned threshold.
The paper shows that closed-form expressions can be obtained by relying on the Equivalent Triangular Storm (ETS) model and that the adequacy of the estimations improves for larger values of the significant wave height threshold.
A New Approach of Quantifying Top-Tensioned Risers Clashing by Using Wavelet Scalograms
Authors: Xing Shutao , Dai Wentao , Moorthy Dakshina , Li Gangqiang 
Published: October 2015

Clashing or colliding can take place between a riser and its adjacent risers or other lines/structures. Clashing is of great concern for the design of top-tensioned riser (TTR) arrays in deep water. Understanding the impact behavior between risers is essential for developing reliable clashing mitigation approaches during design phase. Further, monitoring of risers clashing is useful during operation and installation of the systems.
A critical consideration of clashing monitoring is how to quantify the impact. Traditional methods need a priori information which is difficult to be obtained accurately. This paper proposed a new method of monitoring risers clashing by using wavelet scalograms of dynamic responses that doesn’t need such priori information. The method was investigated through numerical simulation of a pair of TTR risers operated from tension-leg platform (TLP) that are subjected to current and floater motions. The wavelet scalograms of the risers’ velocities and accelerations were utilized to quantify impact. It was verified that the wavelet scalograms can indicate clashing severity quite well.
Deformation Capacity of Weld Seam of the High Quality HFW Linepipe
Authors: Igi Satoshi , Yabumoto Satoru , Sadasue Teruki , Tajika Hisakazu , Oi Kenji 
Published: October 2015

Newly-developed high quality high frequency electric resistance welded (HFW) linepipes have recently been used in pipelines in reel-lay applications and low temperature service environments because of their excellent low temperature weld toughness and cost effectiveness. In order to clarify the applicability of these HFW linepipes to the seismic environment, a series of full-scale tests such as bending test with internal pressure and uniaxial compression test were conducted according to the seismic design code in Japan gas association (JGA).
Based on the above-mentioned full-scale tests, the safety performance of high quality HFW linepipe to apply to the seismic region is discussed in comparison with the mechanical properties in the small-scale tests such as the tensile and compression property of the base material and weld seam, especially focused on the strain capacity of HFW linepipe from the view points of full-scale performance and geometrical imperfection.
Test results of the bending test with internal pressure and the uniaxial compression were complied with the JGA seismic design code for the permanent ground deformation induced by lateral spreading and surface faults.
A Collaborative Approach to Root Cause Analysis: With Reference to Suncor Energy Terra Nova Flexible Flowlines and Risers
Authors: Karabelas George , Redfern Geoff , Jacobs Brad , Roberts Andrew , Fernando Upul , Tink Brian , Varley Mark 
Published: October 2015

One riser and two flowline sections installed in the Suncor Energy Terra Nova riser replacement programme were shown to leak during field tests performed after site installation. No hydrocarbon loss occurred nor was there an environmental incident; however, the scheduled production start-up for the pipes was delayed. The pipes were designed and manufactured to comply with API [1] code and had successfully undergone full-scale factory acceptance testing (FAT) at 1.5 times design pressure following manufacture. Investigations confirmed that the leaks in both pipes occurred due to a crack in the polymer (PVDF) barrier within the end-fitting region of the pipe. It was also concluded that the crack in the barrier in these pipes occurred after completion of the FAT and sometime during the transportation, storage and subsequent installation of the pipes in the field. It was identified that the problem in the barrier resulted from an unknown thermo-mechanical loading condition of the pipe during this period, and also related to specific design features of some components in those end-fittings.
The TapRoot Root Cause Analysis (RCA) tool was used to guide the investigation effort and consider all available data. Small and full-scale tests were performed to simulate and understand the end fitting design in the environments and conditions experienced during transport, installation and offshore testing.
What is presented here is a brief outline of the incident and details of the subsequent investigation. The investigation was conducted over a period of 18 months with the participation of all parties involved in the design, manufacture, installation and operation of the flexibles. This paper summarises the investigation process followed, documents the results, discusses the results and outlines the conclusions and recommendations arising from this investigation.
FEA Analysis of Subsea Mooring Suction Anchor Under Operation Condition
Authors: Wang Shuqin , Zhang Jiaping , Malachowski Jim , Hossain Jubair , Colling James 
Published: October 2015

The analysis of a mooring suction anchor involves both geotechnical and structural engineering. The design starts with the geotechnical analysis of a mooring suction anchor where the design loads are used to determine the size of the mooring suction anchor.
Typically, a conservative estimate would be made for the soil strength and analysis would involve several layers of soil with different properties. The mooring suction anchor is then designed using the relevant soil parameters for various limit states under the combined vertical, lateral, torsional, and moment loading. Soil pressures or reactions acting on a rigid steel mooring suction anchor for each limit state are calculated. The calculation results are then provided to structural engineers to perform strength analysis to verify the integrity of the anchor. Therefore, it is important to understand how the soil reactions interact with the suction anchor in the structural model.
The current analysis used the soil reaction data developed for an in-place loading condition for a mooring suction anchor. The structure of the mooring suction anchor was modelled using a 3D finite element method. Two studies were performed. The first study performed the regular mapping of the soil pressure to the suction anchor. The second study assumed that all the loads would be applied on the mooring padeye and the bottom of the suction would be fixed. It was presumed that the second study would yield a conservative result. However, the analysis results showed that the second study did not provide a conservative result. Therefore, it is recommended that the care should be taken when making such assumptions in future studies.
The Connection between Persistent, Disinfectant-Resistant Listeria monocytogenes Strains from Two Geographically Separate Iberian Pork Processing Plants: Evidence from Comparative Genome Analysis
Authors: Ortiz Sagrario , López-Alonso Victoria , Rodríguez Pablo , Martínez-Suárez Joaquín V. 
Published: October 2015

ABSTRACT

The aim of this study was to investigate the basis of the putative persistence of
Listeria monocytogenes
in a new industrial facility dedicated to the processing of ready-to-eat (RTE) Iberian pork products. Quaternary ammonium compounds, which included benzalkonium chloride (BAC), were repeatedly used as surface disinfectants in the processing plant. Clean and disinfected surfaces were sampled to evaluate if resistance to disinfectants was associated with persistence. Of the 14 isolates obtained from product contact and non-product contact surfaces, only five different pulsed-field gel electrophoresis (PFGE) types were identified during the 27-month study period. Two of these PFGE types (S1 and S10-1) were previously identified to be persistent and BAC-resistant (BAC
r
) strains in a geographically separate slaughterhouse belonging to the same company. The remaining three PFGE types, which were first identified in this study, were also BAC
r
. Whole-genome sequencing and
in silico
multilocus sequence typing (MLST) analysis of five BAC
r
isolates of the different PFGE types identified in this study showed that the isolate of the S1 PFGE type belonged to MLST sequence type 31 (ST31), a low-virulence type characterized by mutations in the
inlA
and
prfA
genes. The isolates of the remaining four PFGE types were found to belong to MLST ST121, a persistent type that has been isolated in several countries. The ST121 strains contained the BAC resistance transposon Tn
6188
. The disinfection-resistant
L. monocytogenes
population in this RTE pork product plant comprised two distinct genotypes with different multidrug resistance phenotypes. This work offers insight into the
L. monocytogenes
subtypes associated with persistence in food processing environments.
Comparative Adjuvant Effects of Type II Heat-Labile Enterotoxins in Combination with Two Different Candidate Ricin Toxin Vaccine Antigens
Authors: Vance David J. , Greene Christopher J. , Rong Yinghui , Mandell Lorrie M. , Connell Terry D. , Mantis Nicholas J. 
Published: October 2015

ABSTRACTType II heat-labile enterotoxins (HLTs) constitute a promising set of adjuvants that have been shown to enhance humoral and cellular immune responses when coadministered with an array of different proteins, including several pathogen-associated antigens. However, the adjuvant activities of the four best-studied HLTs, LT-IIa, LT-IIb, LT-IIbT13I, and LT-IIc, have never been compared side by side. We therefore conducted immunization studies in which LT-IIa, LT-IIb, LT-IIbT13I, and LT-IIc were coadministered by the intradermal route to mice with two clinically relevant protein subunit vaccine antigens derived from the enzymatic A subunit (RTA) of ricin toxin, RiVax and RVEc. The HLTs were tested with low and high doses of antigen and were assessed for their abilities to stimulate antigen-specific serum IgG titers, ricin toxin-neutralizing activity (TNA), and protective immunity. We found that all four HLTs tested were effective adjuvants when coadministered with RiVax or RVEc. LT-IIa was of particular interest because as little as 0.03 μg when coadministered with RiVax or RVEcproved effective at augmenting ricin toxin-specific serum antibody titers with nominal evidence of local inflammation. Collectively, these results justify the need for further studies into the mechanism(s) underlying LT-IIa adjuvant activity, with the long-term goal of evaluating LT-IIa's activity in humans.
Molecular Characterization of Nonhemolytic and Nonpigmented Group B Streptococci Responsible for Human Invasive Infections
Authors: Six Anne , Firon Arnaud , Plainvert Céline , Caplain Camille , Touak Gérald , Dmytruk Nicolas , Longo Magalie , Letourneur Franck , Fouet Agnès , Trieu-Cuot Patrick , Poyart Claire 
Published: October 2015

ABSTRACT

Group B
Streptococcus
(GBS) is a common commensal bacterium in adults, but is also the leading cause of invasive bacterial infections in neonates in developed countries. The β-hemolysin/cytolysin (β-h/c), which is always associated with the production of an orange-to-red pigment, is a major virulence factor that is also used for GBS diagnosis. A collection of 1,776 independent clinical GBS strains isolated in France between 2006 and 2013 was evaluated on specific medium for β-h/c activity and pigment production. The genomic sequences of nonhemolytic and nonpigmented (NH/NP) strains were analyzed to identify the molecular basis of this phenotype. Gene deletions or complementations were carried out to confirm the genotype-phenotype association. Sixty-three GBS strains (3.5%) were NH/NP, and 47 of these (74.6%) originated from invasive infections, including bacteremia and meningitis, in neonates or adults. The mutations are localized predominantly in the
cyl
operon, encoding the β-h/c pigment biosynthetic pathway and, in the
abx1
gene, encoding a CovSR regulator partner. In conclusion, although usually associated with GBS virulence, β-h/c pigment production is not absolutely required to cause human invasive infections. Caution should therefore be taken in the use of hemolysis and pigmentation as criteria for GBS diagnosis in routine clinical laboratory settings.
Structure/Function Studies Involving the V3 Region of the HIV-1 Envelope Delineate Multiple Factors That Affect Neutralization Sensitivity
Authors: Zolla-Pazner Susan , Cohen Sandra Sharpe , Boyd David , Kong Xiang-Peng , Seaman Michael , Nussenzweig Michel , Klein Florian , Overbaugh Julie , Totrov Max 
Published: October 2015

ABSTRACTAntibodies (Abs) specific for the V3 loop of the HIV-1 gp120 envelope neutralize most tier 1 and many tier 2 viruses and are present in essentially all HIV-infected individuals as well as immunized humans and animals. Vaccine-induced V3 Abs are associated with reduced HIV infection rates in humans and affect the nature of transmitted viruses in infected vaccinees, despite the fact that V3 is often occluded in the envelope trimer. Here, we link structural and experimental data showing how conformational alterations of the envelope trimer render viruses exceptionally sensitive to V3 Abs. The experiments interrogated the neutralization sensitivity of pseudoviruses with single amino acid mutations in various regions of gp120 that were predicted to alter packing of the V3 loop in the Env trimer. The results indicate that the V3 loop is metastable in the envelope trimer on the virion surface, flickering between states in which V3 is either occluded or available for binding to chemokine receptors (leading to infection) and to V3 Abs (leading to virus neutralization). The spring-loaded V3 in the envelope trimer is easily released by disruption of the stability of the V3 pocket in the unliganded trimer or disruption of favorable V3/pocket interactions. Formation of the V3 pocket requires appropriate positioning of the V1V2 domain, which is, in turn, dependent on the conformation of the bridging sheet and on the stability of the V1V2 B-C strand-connecting loop.IMPORTANCEThe levels of antibodies to the third variable region (V3) of the HIV envelope protein correlate with reduced HIV infection rates. Previous studies showed that V3 is often occluded, as it sits in a pocket of the envelope trimer on the surface of virions; however, the trimer is flexible, allowing occluded portions of the envelope (like V3) to flicker into an exposed position that binds antibodies. Here we provide a systematic interrogation of mechanisms by which single amino acid changes in various regions of gp120 (i) render viruses sensitive to neutralization by V3 antibodies, (ii) result in altered packing of the V3 loop, and (iii) activate an open conformation that exposes V3 to the effects of V3 Abs. Taken together, these and previous studies explain how V3 antibodies can protect against HIV-1 infection and why they should be one of the targets of vaccine-induced antibodies.