bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population-Wide Folic Acid Fortification and Preterm Birth: Testing the Folate Depletion Hypothesis
Authors: Naimi Ashley I. , Auger Nathalie 
Published: February 2015

Objectives. We assess whether population-wide folic acid fortification policies were followed by a reduction of preterm and early-term birth rates in Québec among women with short and optimal interpregnancy intervals. Methods. We extracted birth certificate data for 1.3 million births between 1981 and 2010 to compute age-adjusted preterm and early-term birth rates stratified by short and optimal interpregnancy intervals. We used Joinpoint regression to detect changes in the preterm and early term birth rates and assess whether these changes coincide with the implementation of population-wide folic acid fortification. Results. A change in the preterm birth rate occurred in 2000 among women with short (95% confidence interval [CI] = 1994, 2005) and optimal (95% CI = 1995, 2008) interpregnancy intervals. Changes in early term birth rates did not coincide with the implementation of folic acid fortification. Conclusions. Our results do not indicate a link between folic acid fortification and early term birth but suggest an improvement in preterm birth rates after implementation of a nationwide folic acid fortification program.
Use of Life Course Work–Family Profiles to Predict Mortality Risk Among US Women
Authors: Sabbath Erika L. , Guevara Ivan Mejía , Glymour M. Maria , Berkman Lisa F. 
Published: February 2015

Objectives. We examined relationships between US women’s exposure to midlife work–family demands and subsequent mortality risk. Methods. We used data from women born 1935 to 1956 in the Health and Retirement Study to calculate employment, marital, and parenthood statuses for each age between 16 and 50 years. We used sequence analysis to identify 7 prototypical work–family trajectories. We calculated age-standardized mortality rates and hazard ratios (HRs) for mortality associated with work–family sequences, with adjustment for covariates and potentially explanatory later-life factors. Results. Married women staying home with children briefly before reentering the workforce had the lowest mortality rates. In comparison, after adjustment for age, race/ethnicity, and education, HRs for mortality were 2.14 (95% confidence interval [CI] = 1.58, 2.90) among single nonworking mothers, 1.48 (95% CI = 1.06, 1.98) among single working mothers, and 1.36 (95% CI = 1.02, 1.80) among married nonworking mothers. Adjustment for later-life behavioral and economic factors partially attenuated risks. Conclusions. Sequence analysis is a promising exposure assessment tool for life course research. This method permitted identification of certain lifetime work–family profiles associated with mortality risk before age 75 years.
Physical Activity in Adults with Cystic Fibrosis Receiving Intravenous Antibiotics in Hospital and in the Community§
Authors: Khiroya Heena , Pound Rebecca , Qureshi Ushna , Brown Catherine , Barrett Joanne , Rashid Rifat , Whitehouse Joanna L. , Turner Alice M. , Nash Edward F. 
Published: February 2015

Introduction :Intravenous antibiotic therapy (IVAT) for CF acute pulmonary exacerbations (APE) can be delivered in hospital or in the community. This study aimed to compare physical activity in CF patients receiving hospital and community-delivered IVAT, as well as other health outcomes.Materials and Methods :This was a non-randomised parallel group prospective observational study. Hospitalised and community-treated CF adults receiving IVAT for APE were asked to wear ActiGraph® activity monitors, complete the habitual activity estimation scale (HAES), food diary, modified shuttle test (MST) and CFQ-R at the start and end of therapy. Nutritional and clinical outcomes were also compared between the cohorts. The primary outcomes was physical activity measured by the ActiGraph® activity monitors at the beginning and end of treatment in both cohorts.Results :Physical activity (measured and self-reported) was no different between the cohorts, with both hospitalised and community-treated subjects being generally sedentary. Body weight increased significantly in the hospitalised cohort, whereas no difference was seen in the community-treated cohort. FEV1 % predicted and FVC % predicted increased in community-treated subjects, whereas only FVC % predicted increased in hospitalised subjects. CFQ-R respiratory domain increased to a greater extent in community-treated subjects.Conclusion :CF adults receiving IVAT for APE, both in hospital and in the community, are generally sedentary and we found no difference in physical activity between the two groups. These findings suggests the need to further promote physical activity in suitable patients during APE where considered appropriate.
Technical Notoe: Prediction of Static Liquefaction by Nor Sand Constitutive Model
Authors: Sternik Krzysztof 
Published: February 2015

Abstract
The paper gives a short description of unstable behaviour of saturated sand under undrained monotonic loading. Constitutive model Nor Sand capable to describe static liquefaction is presented. The model is based on critical state soil mechanics and assumes associated flow rule. Hardening law incorporates the state parameter proposed earlier by Been and Jefferies. Results of numerical simulations of undrained element tests have been presented and discussed.
Dynamic Response of Three-Layered Annular Plate with Imperfections
Authors: Pawlus Dorota 
Published: February 2015

Abstract
This paper presents the imperfection sensitivity of annular plate with three-layered structure. The plate composed of thin elastic facings and a thicker elastic core is loaded in facing plane. The classical issue of a three-layered plate was solved for dynamic deflection problem using the approximation methods: orthogonalization and finite difference. The solution includes the axisymmetric and asymmetric plate modes of the dynamic stability loss. The evaluation of the rate of plate sensitivity to imperfection of plate preliminary geometry has been enriched by the analysis of plate models built of finite elements. The ABAQUS program has been used. The numerous calculation results in the form of deflection characteristics, buckling modes, values of critical parameters create the view of response of dynamic plate structure with different rate of imperfection and linear in time loading growth, too.
Installation of Dual-Riser Combination onto the Existing Jacket
Authors: Zhou Shengjie , Li Daquan , Wang Jianming , Wang Wenlong , Chen Dajiang , Qiu Chaopeng , Liang Siyin , Jin Tongjun , Zhou Dongrong , Chen Shi , Yin Yankun , Deng Xin 
Published: February 2015

The YC13–4 gas field in South China Sea is tied into the developed YC13–1 gas field existing facilities nearby. The CRA clad carbon steel gas riser and carbon steel umbilical protective riser are designed and together installed onto the existing jacket of YC13–1 gas field.
In order to ensure the welding quality of the CRA clad gas riser, avoid the high risks of simultaneous operations of production, hot works and installation, and taking into account of natural gas operational conditions of high temperature and high pressure around YC13–1 gas field existing platform, the installation method of dual-risers (gas riser and umbilical protective riser) together onto the existing jacket is used. The CRA clad gas riser and umbilical protective riser are designed, fabricated and precisely assembled on land forming dual-risers upper and lower parts together with fastening clamps based on measuring data of existing jacket correspondingly. The lower part is installed at first and then upper part. Each part is lifted, submerged in water, up-righted under the help of intentionally added buoyancy and then moved close to jacket by winch. The lower and upper parts are joined by bolted flange at last.
The installation of dual-risers together onto the existing jacket for YC13–4 gas field is actually completed within 10 days. This method avoids the close support from the existing platform and works efficiently.
Subsea Processing : Oil/Water Quality Control
Authors: Eriksson Klas 
Published: February 2015

This paper discusses briefly some of the most vital performancecontrol loops for a subsea oil/water separation processes, a subsearaw seawater chlorination/injection plant, and a subsea compressionplant. Monitoring issues for a subsea separation plant:–The oil quality needs to be monitored (such that there is not toomuch water in it).–The water quality needs to be monitored (such that there is not toomuch oil and sand in it).–Sand may accumulate in the separator vessel, and ultimately fill itup such that it no longer operates properly. The sand deposition needsto be monitored, and the sand flushed out when necessary.
Monitoring issues for a subsea compression plant:–Liquid carryover from scrubber to compressor needs to be monitored–Solids build-up in scrubber need to be nmonitored Monitoring issues for a subsea seawater chlorination/injection plant:–Solids content in injection water–Live bacteria content in injection water
Monitoring issues for a subsea raw seawater injection plant:Solids content in injection waterBacteria content in injection water
The 6 main control loops discussed in this paper are thus:. Separation Oil quality sensing and control. Separation Water quality sensing and control. Sand deposition sensing and control. Liquid carry-over sensing and control. Solids content monitoring and control in injection water. Bacterial content monitoring and control in injection water
Sensing and mitigating options are discussed.
Effective Lateral Buckling Mitigation for Deepwater Flowline
Authors: Lim Kok Kien , Lau Siew Ming 
Published: February 2015

There is an increasing trend of pipelines operating at temperature in excess of 100 °C, particularly in deepwater production flowlines. These pipelines are generally of small diameter and often also operating at relatively high pressure. The combination of high temperature with high pressure leads to design challenges with respect to lateral buckling mitigation requirements.
In line with this development, a noble lateral buckling design mitigation scheme involving combined vertical and lateral offsets incorporated in a conventional sleeper concept has been developed [Ref. 1]. This so called Zero-Radius-Bend (ZRB) method significantly improves the buckle initiation reliability and its effectiveness has been field proven on many recent projects. However, ZRB track record to date has been limited to relatively shallow water in the range of 50m-100m water depth using conventional S-lay pipeline installation method.
This paper first describes the ZRB buckle mitigation method, its unique characteristics and ensuing advantages over the conventional sleeper method, followed by specific design and analysis considerations for deepwater application using reel-lay or J-lay installation method to create the lateral offset. The feasibility of ZRB is demonstrated through advanced three-dimensional finite-element (ABAQUS) modelling of pipe response, from progressive pipe laying, to pre-commissioning to first start-up and through to eventual operating cyclic loads from thermal and pressure cycles. Changes in pipe material post-yielding properties due to reeling/unreeling cycles and their impacts on buckle response are also considered.
Deepwater production flowlines also tend to be relatively short and, coupled with high operating and low ambient temperature, can lead to global axial walking response driven by the thermal gradient during the transient restart condition, following a full or partial shutdown. Excessive axial walking can have serious impacts on flowline tie-in spool design and connector loads. Axial walking can also interact and change the buckle profile affecting its overall characteristics. The effects of walking, its impacts on buckle response and tie-in spool design are demonstrated and captured in a single FEA model to illustrate the overall flowline behaviours under cyclically high thermal and pressure loads.
Reference (1): Subsea Australasia Conference 2011, "Lateral Buckling Design And Field Verification", Lim & Lau, et. al.
The Effects of Geomechanics on the WAG Injection Model
Authors: Bataee M. , Irawan S. , Majidaie S. 
Published: February 2015

Geomechanics is the study of the rock elastic or plastic behavior and has direct impact on well integrity. Wellbore instability is a serious drilling problem that costs the oil industry over US$500–1000 million each year. Over the past two decades the geo-mechanical analysis has made major changes in the petroleum industry by maximizing production and increasing the life of the well. Water alternating gas (WAG) injection has been a popular method for commercial gas injection projects worldwide.
The main objective of this paper is to determine the effects of geomechanics on reservoir flow for the water alternating gas (WAG) process. The WAG injection pressure, temperature and the initial in-situ stress is important to determine the stress after the injection. The change in stress changes the porosity, permeability and subsequently the flow pattern changes.
There are some methods to investigate the effects of geomechanics on reservoir simulation, as implicit, explicit, iterative and psudo-coupling method. In this study we use the iterative coupling method. In this type of coupling, reservoir flow variables and geomechanics variables are solved by a reservoir simulator and a geomechanics module, and the coupling terms are iterated on at each time step. The results show the difference in the flow patterns, porosity and permeability with and without considering the geomechanics.
Open Hole Formation Testing and Sampling in Shallow and Low Pressure Gas Reservoirs: Best Practices and Lessons Learned
Authors: Trebolle Ramiro , Okamoto Maruro , Haddad Sammy , Wa Wee Wei 
Published: February 2015

Cendor Graben Shallow sands are 35 Km2 of gas accumulation at depth varying from 350-450mss over the Jambu-Liang anticline, defined by high amplitude in seismic, containing hydrocarbon gas (C1-C3gas indicated by mudlogs) with the possibility of high CO2; possibly charged from deeper sources though fault seeps.
Shallow Gas reservoirs also due to the unconsolidated formation present unique measurement and operations challenges to the wireline formation tester (WFT) in pretesting and sampling due to its nature of high compressibility especially at low pressure. Often the high gas compressibility results in a larger pretest drawdown volume needed to decompress the flowline and to reduce the flowline pressure below the formation pressure for a valid formation pressure measurement. The good mobility formation further complicates the flowline decompression due to a very small pressure drawdown. In addition, at the start of pretest build-up period, a pressure build-down behavior was observed and has greatly affected the formation pressure stabilization and mobility calculation.
On the other hand, gas sampling in such low pressure and unconsolidated formation introduces great difficulties in balancing the samples bottle filling and sand production initiation which may potentially plugged the downhole pump-out module. The station time limitation commonly imposed by the drillers making the sampling process even more challenging. In the past, companies often considered these sands as drilling hazards and not targets for exploitation. This testing validated the importance of formation testing in shallow unconsolidated gas reservoirs by preventing formation failure that could lead to plugging. The small sand particle sizes and unconsolidated nature of the formation makes it very difficult to control sand production.
This work presents an exploration work done in a very shallow and low pressure gas bearing formation, which exposes the WFT to a combination of unconsolidated formation and high gas compressibility challenges. Best practices are established and discussed in this paper to address the aforementioned challenges to enable a successful WFT evaluation in the shallow, low pressure gas reservoirs.
Technical and Economical Comparison of Subsea Active Heating Technologies
Authors: Ansart Bruno , Marret Antoine , Parenteau Thomas , Rageot Olivier 
Published: February 2015

Active heating of subsea flowlines is an attractive solution for facing flow assurance issues related to always going deeper and longer, as well as more complex fluids and critical wellhead flowing conditions (pressure, temperature, flowrate) prone to pour point issues, hydrates and/or wax appearance risk.
Over the last 15 years, several active heating technologies have been developed and operated in order to significantly help solve flow assurance issues from the subsea wellheads up to the surface support facilities. These technologies have demonstrated to be very different in their design and operability (use of hot water, direct or indirect electrical heating) but also in their efficiency and cost.
In parallel with the development of heated flexible pipe designated IPB (Integrated Production Bundle) already used for field development in West Africa and Brazil as well as a rigid heated pipe-in-pipe technology, both using electrical heat trace cables, Technip has been involved in the design, construction and installation on several projects of all active heating technologies.
Based on this extensive knowledge and track-record, this paper describes and compares the working principle as well as the advantages and drawbacks of the different active heating technologies. This paper also identifies their limitations with regards to field application, i.e. length and water depth based on their actual development status.
On the basis of different generic case studies (shallow long tie-back, shallow in-field development, deep water tie-back and ultra-deep water in-field development), this paper finally reviews all the potential benefits the different active heating technologies can bring to a project and includes an economical comparison of these technologies.
Method to Assess the Overtrawlability of Pipe-in-Pipe
Authors: Zheng Jiexin , Palmer Andrew , Brunning Paul , Lim Gerry , Shu Sun 
Published: February 2015

This paper summarizes a three-year research on the overtrawlability of pipe-in-pipe, and develops the method to access it. Overtrawlablity is the ability of the pipe to resist the trawl gear impact and the pull-over force. The trawl gear will first impact the pipe and then pull over the pipe. If the overtrawlable capacity of the pipeline is insufficient, the trawl gear may damage the pipeline by denting or bending the pipe heavily. Overtrawlability of the pipeline has a direct bearing on whether the pipeline needs to be protected by burial with significant cost savings if burial is not required.
DNV-RP-F111 and the other industry guidelines give a method to estimate the overtrawlability, but currently there is no method specifically for pipe-in-pipe. The outer pipe gives the inner pipe extra protection, and it does not have to resist internal pressure and can therefore accommodate a greater level of indentation than a single-wall pressure-containing pipe. If we apply the approach for the single wall pipe to pipe-in-pipe, the results are likely to be conservative. Therefore, an assessment of the overtrawlability of pipe-in-pipe is necessary to be conducted before making any trenching decisions, and to avoid providing unnecessary protection.
With this motivation, a three-year JIP has been conducted at the National University of Singapore to better understand the overtrawlability of pipe-in-pipe, and to find the method to assess it. The research includes three different experiment programs to investigate the impact and pull-over responses. FE models of indentation and impact are developed and validated against first-hand experimental data. A new relationship of load-deflection relationship is developed to assess the impact response. External pressure is considered by the FE model using hydrostatic fluid element. Small scale pull-over experiments are conducted to study the pull-over force for different pipes and different conditions.
The research work altogether develops the way to analysis the response of pipe-in-pipe when it interacts with a trawl gear. Finally, A comparison between a pipe-in-pipe and a single wall pipe shows the difference between them and throws light on the issue of trenching for pipe-in-pipes to some extent.
Design of the Surface Flow Test System for 1st Offshore Production Test of Methane Hydrate
Authors: Terao Yoshihiro , Lay Kevin , Yamamoto Koji 
Published: February 2015

Description:
As a paper of the MH21 study, this paper describes the design and operation of the surface flow test system utilized for the 1st Offshore Production Test of Methane Hydrate in deep water offshore Japan in March 2013 using a dynamically positioned drill ship. The unique characteristics of this production test required a customized approach to the design of this system. As the production test was carried out for scientific research purposes, the data acquisition requirements were of paramount importance.

Application:
The information contained in this paper can be applied to future offshore production tests of methane hydrate using the depressurization technique.

Results, Observations, and Conclusions:
The surface flow test system was successfully designed, installed, commissioned and operated. Measurement and separation of the produced gas and water were effectively achieved under low temperature, low pressure, and low production rate conditions. Transportation and operation of surface flow test equipment was able to accommodate the motions of the floating drilling vessel. Two separate fluid processing trains were installed for high quality measurement of the gas and water rates. A real time data sharing system to monitor the condition of the surface system and the down hole systems implemented but shut down of the downhole equipment was not triggered automatically by surface production equipment ESD. Some non-critical data acquisition failures occurred or limitations observed during the production test.

Significance of Subject Matter:
It is believed that this was the first offshore production test of methane hydrate to have been conducted in the world. The design philosophy and operational experience will be useful for future production testing in similar environments.