bluuebunny/crossref_metadata_2025_split huggingface dataset:
Importance of Detailed Terrain and Geohazard Information for Pipeline and Infrastructure Developments in Arctic Environments
Authors: O'Leary Dennis , Garrigus Andrew , Krzewinski Thomas 
Published: October 2018

Abstract
Pipelines and roads represent the arteries of the oil and gas, and mining and transportation industries, respectively. They move product from remote locations to more centralized locations, either for processing or for shipping to refineries and mills for subsequent processing. Proper infrastructure development is critical to the successful development of the sensitive Arctic environment especially true in light of ongoing climate change where the melting of permafrost poses significant issues for development in the Arctic. The harsh Arctic environment presents unique challenges that are not found in more southern latitudes for the oil and gas and transportation sectors, including permafrost and permafrost degradation. It is well acknowledged that the extent of permafrost in northern environments is poorly known and mapped.
New tools are being used to help determine the extent of permafrost and to identify areas that are more susceptible to permafrost degradation in light of on-going and future development. One such tool is the use of softcopy mapping to help map terrain and geological modifying processes such as permafrost. Softcopy uses traditional stereo aerial photographs in a digital environment to allow scientists the ability to view the landscape at scales of 1:1,000 from traditional aerial photography that were captured at scales of 1:24,000 to 1:40,000. The advantage of softcopy is that by being able to zoom down to such large scales allows terrain scientists the ability to better determine the soil types (sand, silt or clay), drainage conditions (rapid to very poor) and on-going geological processes such as permafrost as evidenced by frost boils and permafrost degradation as evidenced by presence of thermokarst and thaw slides. Another method often utilized where stereo aerial photography is not available is use of remote sensing datasets such high resolution digital elevation models and satellite imagery which are becoming general available in Arctic regions. These elevation models are used to create hillshade images of varying aspects and photorealistic 3D models to help map terrains.
This paper will present a number of examples of where such mapping has been used to assist in pipeline and infrastructure planning in Alaska and Canada's north.
Solid Propellant Accumulators – Next Generation Hydraulic Power Source for Cold Weather BOP's
Authors: Bedrossian Nazareth 
Published: October 2018

Abstract
This paper describes a new type of piston accumulator which uses a solid propellant gas generator to pressurize hydraulic fluid. It is a self-contained device in that both the power source and hydraulic fluid are packaged together in single accumulator. The device rapidly supplies high pressure and high flowrate hydraulic fluid on-demand much like an airbag system for automobiles. It is particularly suited for emergency applications such as closing of subsea BOP shear rams, closing pipeline valves, etc. A conventional piston accumulator can be easily retrofitted with a gas generator cartridge with only minor cap and piston modifications. Retrofitting a conventional compressed gas accumulator with a gas generator cartridge increases the performance of the accumulator by nearly 10X in terms of usable fluid, reliability, weight, and volumetric footprint. Additionally, the gas generator equipped accumulator requires essentially no maintenance and has a service life of more than 10 years. In DMAS applications it can be used in a "Direct-To-Hydraulics" mode by connecting the accumulators directly to the shear rams without the need for any valves other than a check valve. It also eliminates the hydraulic delay system in the DMAS with an electronic delay between CSR and BSR activation, and does not need a complex control system.
Field Experiments on Shear Strength of Solid and Freeze-Bonded Sea Ice
Authors: Boroojerdi Marjan Taghi , Taylor Rocky , Mohammadafzali Soroosh , Bailey-Dudley Eleanor , Turnbull Ian , Hossain Ridwan 
Published: October 2018

Abstract
Sea ice rubble/ridge strength and interaction mechanics are highly important in the design of structures and subsea infrastructure for ice prone offshore environments. To better characterize sea ice conditions in northern Newfoundland, a series of field tests were conducted on landfast ice in Pistolet Bay, NL in February 2018. This paper presents a summary of recent shear strength tests on solid and freeze-bonded ice specimens, to help improve understanding of ice rubble properties and behaviour under field conditions. Both horizontal and vertical sea ice samples were tested under dry and submerged conditions, as well as freeze-bonded ice samples under submerged conditions. Sea ice samples were sheared using the Asymmetric Four Point Bending (AFPB) method, which has been shown to produce a near pure shear region at the center of the specimen. For the dry tests, cores were sheared directly after collection so as to test them in conditions as close to in-situ as possible. For submerged tests, cores were submerged for a specific period of time before shearing. Freeze-bonded samples were prepared using a confinement frame which applied a pressure of 25 kPa to the specimens during submergence. These data for AFPB field tests are an important consideration in modelling the strength of ice rubble/ridges and are the first of their kind. From this work it may be concluded that the AFPB method is a promising approach for studying shear strength of both solid and freeze-bonded specimens in the field and additional testing is recommended. New field testing approaches, such as the one presented here, will help improve understanding of in-situ sea ice properties and behavior, which ultimately supports the development of new ice-structure interaction models, which directly benefits oil and gas, shipping, renewable energy, and public works projects in ice prone Arctic and Sub-Arctic regions.
Full Scale Trials for the Validation of Ship Performance and Model Tests in Ice
Authors: Reimer N. , Hisette Q. , Schroeder C. 
Published: October 2018

Abstract
The paper addresses methods used to analyse full scale trials for performance determination of ships in ice. Furthermore uncertainties resulting from assumptions taken in the early stage when ice model tests are typically performed are discussed. In a first step the difference between model test based prediction and final determined performance from ice trial are shown for an example ship for which both results are available. The main assumptions are critically reviewed and possible reasons for deviations between the prediction and final outcome of ice trials are systematically assessed. The performance of ships in ice determined by model testing based on single combinations of speed and ice thickness is compared to full scale trial results. Furthermore the effect of generalizing impact friction and snow cover which is usually generalized for the model based prediction is determined by different methods. Finally a comparison between the propeller-ice interaction based on model tests and full scale trials is made to assess possible sources and magnitude of deviations between the performance prediction in early design stage and the final trial results.
The paper shows that even though the prediction of icebreaking resistance by theoretic means and by model testing is well established comparisons between performance results obtained from ice trials sometimes deviate in their values and trends from those predictions. Besides testing uncertainties also missing parameters and testing methods can be identified as reasons for differences in the results. Recorded time series of propeller ice interaction in full scale and model scale are compared and analyzed. Different scaling approaches are applied to the model scale torque trends and compared to the full scale data. The results of the comparison between full scale and model test results show the limits of the current methods and encourage to take a closer look at additional parameters with stronger influence on ice performance. Additionally the comparisons of ship performance and propeller ice interaction of model and full scale data will improve the understanding of the transferability from model to full scale data.
Discrete Element Simulation of Ships Navigating Through Brash Ice Channels
Authors: Prasanna M. , Hisette Q. 
Published: October 2018

Abstract
The paper describes a simulation tool for simulating the transit of ships through brash ice channels, based on the Discrete Element Method (DEM). Fundamentals of the method are given, including contact detection and forces calculation. Artificial brash ice channels are created in the simulation domain by the so-called floating-up technique. Hull geometry is introduced into the model, handling non-convex bodies as composites of convex bodies. Hydrostatic properties are calculated according to the actual draft, pitch, and roll angles. In order to calibrate the parameters of the code, a standard cylinder experiment is simulated and the results are compared with the experimental model test results. Graphical output of the simulation is also compared with underwater camera footage. General behavior of the ice particles is identical in the vicinity of the structure. However, ice loads on the structure exhibit some discrepancies. Simulation of an Ice Class Tanker was also carried out, and the results were compared with experimental model test values and under water videos. In this case, ice loads tend to be higher than expected. However, particle behavior near hull is very satisfactory. The cause for high ice loads is identified to be deficiencies in modelling the behavior of far field ice particles in the current tool. The simulation tends to overestimate the particle motions in far field due to the deficiencies in the implemented friction model (Cundall-Strack Friction). The current tool is suitable for obtaining qualitative results on ships navigating in brash ice channel in the early design stage; especially to visualize the ice particle flow around ship hull and identify possible concentration of ice particles especially around appendages.
The Design Width of Floating Ice Roads and Effect of Longitudinal Cracks
Authors: Spencer Paul , Wang Ruixue 
Published: October 2018

Abstract
The thickened width of floating ice roads has tended to be a practical consideration rather than a design aspect. Standard methods of calculating the required thickness of ice roads consider the road to be of infinite length and width. In this paper we outline calculations of the bending stress for a finite width ice road. The recommended minimum width that should be thickened to the design value is given below where Lc is the ice characteristic length:
Longitudinal wet cracks reduce the load bearing capacity of an ice road. Stress analysis indicated that as long as the ice is less than 1.83m thick and the footprint of the vehicle is longer than 10 m (33 ft) then a safe and simple to use estimate of the road capacity for a vehicle travelling parallel and adjacent to the crack is given by:
Defining a Path Towards Successful Low Cost Marginal Field Subsea Developments – An Overview
Authors: Muise Jason , Ralph Freeman 
Published: October 2018

AbstractSubsea oil and gas developments in the Grand Banks region, offshore Eastern Canada, require mitigation techniques to protect against iceberg keel interactions. For example, untrenched infield flowlines incorporate weak link systems designed to fail in the event of flowline snag to protect upstream and downstram assets. Even with these systems, the assumption that any iceberg contact equates to flowline failure means that flowline lengths in excess of approximately 10 km require trenching to meet safety target levels. Furthermore, all subsea wells to date have been installed in excavated drill centers to avoid contact with gouging icebergs. Based on current design practices, these mitigation measures are cost prohibitive and limit the potential for the development of marginal fields. This paper addresses conventional practice to protect against iceberg interaction and proposes alternative solutions that maintain safety, while reducing costs significantly.
First Year Ridge Interaction on Upward Sloping Structures: A New Approach
Authors: Croasdale Ken , Brown Tom , Li George , Spring Walt 
Published: October 2018

AbstractNumerous field studies show that mature first-year (FY) ridges consist of a solid ice consolidated layer (CL) below which is a keel of ice rubble. The CL is generally thicker than the ambient level ice. With the decrease in multi-year ice in the Arctic, FY ridges may become the controlling ice feature at many Arctic locations. In sub-Arctic regions ridges are smaller but they also usually control design ice loads. For vertical structures, ISO 19906 (Standard on Arctic Offshore Structures) suggests calculating the load due to crushing of the CL and adding this to the load to fail the keel. In ISO a formula is provided for the load to fail the keel on a vertical-face which assumes that the keel material has Mohr-Coulomb properties. No specific algorithms are given in ISO for FY ridge loads on sloping structures. The work described in this paper addresses this gap.The study investigated three bounding methods and compared them with the measured loads due to FY ridges on Confederation Bridge (which has piers with upward breaking cones). The three bounding methods are: Model A; which assumes the CL breaks in bending and rides up as level ice and the keel load is calculated assuming a "dead wedge" is created on the slope which converts the slope into a vertical face against which the keel fails. This model can make use of the methods in ISO 19906 for calculating these two components and can be considered to be the implied "current ISO approach". Model B assumes that the CL layer fails in bending as "level ice" on an elastic foundation and rides up the slope with the accompaniment of additional ice rubble scooped-up from the sail and keel of the ridge. Model C assumes that the FY ridge can be idealized into an equivalent "solid ice" beam using composite beam theory. Then the beam on elastic foundation method, as used for solid ridges, is used to estimate breaking and clearing loads.These various approaches are reviewed and the derived loads are compared to failure modes and measured loads from Confederation Bridge for selected events involving FY ridges. Based on these comparisons a hybrid of Models B and C is recommended and the paper gives the details of how to apply this method.When used for example structures, the new model gives loads which are 40 – 50% lower than the current approach implied in ISO 19906. The method can be adapted to downward sloping structures.
The Commensal Neisseria musculi Modulates Host Innate Immunity To Promote Oral Colonization
Authors: Powell Daniel A , Ma Mancheong , So Magdalene , Frelinger Jeffrey A 
Published: October 2018

Abstract
Neisseria musculi, isolated from the oral cavity of wild-caught mice, does not colonize most inbred mouse strains. N. musculi does weakly (50%) colonize C57BL/6J (B6) mice but readily colonizes CAST/EiJ (CAST) mice. In this study, we examined whether differences in the CAST and B6 host response could elucidate mechanisms governing N. musculi colonization. In vivo stimulation of B6 or CAST splenocytes with wild type (WT) Neisseria or Escherichia coli LPS showed that CAST mice had a blunted inflammatory response, producing significantly lower levels of IL-6 than B6 mice. The use of specific genetic knockouts highlighted a need for an intact innate immune system to prevent colonization. B6–RAG-1−/− mice were colonized at a similar rate as WT B6 mice, whereas B6-MyD88−/− and TLR4−/− mice were readily colonized like CAST (100%) mice. Sequence analysis revealed a unique point mutation in TLR4 in CAST mice. However, crosses to TLR4−/− mice and analysis of recombinant inbred Collaborative Cross mice showed that TLR4 from CAST mice was not sufficient to allow Neisseria colonization. In vitro stimulation of B6 bone marrow–derived macrophages or splenocytes with WT Neisseria yielded low levels of IL-6 compared with LPS stimulation. Surprisingly, UV-inactivated Neisseria induced high levels of IL-6, suggesting suppression of IL-6 production is an active bacterial process. Consistent with a critical role for IL-6 in preventing colonization, mice deficient for the IL-6 receptor were efficiently colonized, indicating host IL-6 production plays a critical role in determining host colonization susceptibility.
Motivational factors for engaging in dirty work entrepreneurship among a sample of African immigrant entrepreneurs in South Africa
Authors: Cobbinah Charles , Chinyamurindi Willie T. 
Published: October 2018

Orientation: South Africa is witnessing a large number of African immigrants coming into the country. These immigrants seek formal and informal employment. One sector favoured is ‘dirty work’ within the informal sector.Research purpose: To investigate the immigrants’ motivational factors influencing migration and dirty work entrepreneurship in South Africa.Motivation for the study: Because of the dynamic nature of political and economic circumstances that affect a country’s employment options, calls have been made for empirical focus on understanding the career development processes of neglected sample groups such as immigrants and even those engaged in dirty work.Research approach/design and method: A qualitative research approach was utilised based on the narratives and stories of 27 immigrant entrepreneurs in the informal sector engaged in dirty work careers.Main findings: Three narratives emerged as motivating factors for migrating: (1) socio-economic issues, (2) lack of opportunities and (3) experience of a new life. Furthermore, three motivational factors led into dirty work careers: (1) challenges of breaking into formal employment because of immigration rules, (2) motivation from social networks the immigrants belong to and (3) an enterprising spirit, driven by ambition.Practical/managerial implications: Based on the findings, interventions can be proposed to assist not only those engaged in dirty work but also migrants and citizens seeking opportunities in this sector.Contribution/value add: This study advances the literature in dirty work research within a South African context. Further, the study gives currency to an often neglected yet important sample group in dirty work entrepreneurship, who also happen to be immigrants.
Adiós al lenguaje, bienvenido el lenguaje: una aproximación al pensamiento matemático en el cine de Jean-Luc Godard
Authors: López Fernández José Luis 
Published: October 2018

El cine de Jean-Luc Godard apuesta desde el principio por la búsqueda de un lenguaje depurado y renovador, en el que el conocimiento científico ocupa un papel bastante destacado. En particular, el realizador ha asimilado e incorporado satisfactoriamente el pensamiento matemático a diferentes niveles de sus elementos discursivos, como pretendemos reflejar a lo largo de este artículo. De la metáfora al pensamiento político y del montaje a la teoría de la comunicación, la “matematización” del cine de Godard constituye uno de los aspectos más interesantes de su nueva narrativa.
Who Cares for Total Hip Arthroplasty Complications? Rates of Readmission to a Hospital Different From the Location of the Index Procedure
Authors: Chen James B. , Hegde Vishal , Cheung Edward C. , Stavrakis Alexandra I. , SooHoo Nelson F. 
Published: October 2018

Introduction:
While the number of total hip arthroplasties (THAs) performed increases, so is the number of postoperative readmissions, resulting in costly episodes of care that may disproportionately affect certain hospitals. This study examines the rates of readmission of patients to the same hospital at which they underwent index THA, compared with readmission to a different hospital.

Methods:
Data for all hospital discharges from 1995 to 2010 were obtained from the California Office of Statewide Health Planning and Development database. Patient outcomes, readmission data, demographic information, hospital teaching status, and location were analyzed. Regression modeling was used to evaluate the effect of hospital teaching status, location, and individual complications on the risk of readmission to the same hospital as opposed to a different hospital following the index procedure.

Results:
The overall postoperative readmission rate for specific defined complications or all-cause 30-day readmissions was 3.92%, with 75.17% readmitted to the same hospital. Following index THA at a nonacademic or academic hospital, 95.9% and 84.6% of patients were readmitted to the same type of hospital, respectively. Patients who had their index procedure at an academic hospital had lower odds for readmission to the same hospital (odds ratio, 0.734; P < 0.0001) compared with nonacademic centers. Hospitals in midsize towns had higher odds of readmission to the same hospital (odds ratio, 1.735; P = 0.0012) compared with those in large metropolitan areas.

Discussion:
Although more than 75% of patients with unplanned readmissions went to the same hospital as their index THA, academic and larger metropolitan hospitals had higher odds of postoperative readmissions to a different hospital.
Iberian pig adaptation to acorn consumption: I. Net portal appearance of metabolites
Authors: Fernández-Fígares Ignacio , Rodríguez-López Jose Miguel , González-Valero Lucrecia , Lachica Manuel 
Published: October 2018

Most valuable cured products from Iberian pigs come from pure bred animals raised for a final grazing-fattening period where pigs eat mainly acorns, a low protein energy rich fruit. This is a nutritional challenge for animals fed equilibrated diets from weaning. The aim of the study was to determine net portal appearance (NPA) of metabolites in gilts fed acorns and evaluate adaptational changes after one week of feeding. Two sampling periods were carried out (after one day and after one week of acorn feeding) with six gilts (34 kg average BW) set up with three catheters: in carotid artery and portal vein for blood sampling, and ileal vein for para-aminohippuric acid (PAH) infusion to measure portal plasma flow (PPF). Pigs were fed at 2.5 × ME for maintenance a standard diet in two portions, at 09:00 (0.25) and 15:00 h (the remaining 0.75). On the day prior to the first sampling period, pigs were fed 2.4 kg of oak acorns. After feeding 0.25 of ration a 6 h serial blood collection was initiated. Following an identical protocol, a second sampling session was performed 1 week later. Adaptation to acorn consumption decreased NPA of ammonia (47%,P < 0.001). Although there was a transfer of urea from the gastrointestinal tract to the circulation in both sampling periods, no differences in NPA of urea was found (P > 0.05). NPA of glucose was not influenced by sampling period (P > 0.05), but NPA of lactate was greatly increased (231%,P < 0.001). There was a negative NPA of albumin although adaptation to acorn feeding did not alter it. Although NPA of triglycerides and cholesterol were unchanged, a subtle increase in arterial and portal cholesterol was noticed (9.6%,P < 0.01). Pigs fed a protein deficient diet for one week adapted decreasing NPA of ammonia for saving metabolic energy as less ammonia would become available for conversion to urea.