bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Pretreatment Considerations for Floating LNG
Authors: Shane Tierling 
Published: October 2015

Global LNG demand is expected to continue to grow over the next two decades. Some of the new projects required to meet this demand will be developed with floating LNG (FLNG) technologies, to monetize mid-sized offshore reservoirs, eliminating the costly and technically challenging pipeline to a land based LNG facility. FLNG facilities have the potential of serving multiple fields over the life of the facility, reducing the minimum size field that can be economically monetized. The market has affirmed these benefits and projected LNG demand growth with the start of construction of several floating LNG facilities.
Much recent attention has been given to offshore LNG ship-to-ship transfer, topsides layout and liquefaction technology selection for FLNG with lesser coverage of support systems, particularly gas treatment. This paper will address this void by providing an overview of gas treatment for FLNG, highlighting the pretreatment requirements for cryogenic processing that may be unfamiliar to those more grounded in FPSO technology. Cryogenic processing requires removal of water and carbon dioxide to prevent solids formation. The use of brazed or welded aluminum equipment, common in cryogenic processing, requires the removal of mercury. Gas treatment technology selection is impacted by constraints on safety, weight, space, maintainability, flexibility in modularization, and insensitivity to both tilt and motion. Candidate technologies will be explored.
Optimizing Recovery by Integrating an Advanced Reservoir Simulation Approach Into the Drilling of Horizontal Wells
Authors: Salim D. , Couto P. , Alves J. , Freitas E. , Haq S. , Denichou J. M. 
Published: October 2015

With the advent of rotary steerable systems, successful drilling of horizontal wells became a reality in the oilfield. Even though the costs are much higher than for a vertical well, the production factor can be enhanced multiple times, making it very attractive. However, the drilling of horizontal wells is extremely difficult, mainly due to lateral lithological discontinuities of the reservoirs and seismic uncertainties. To overcome such challenge, Well Placement technique is used to interactively position the well based on geological and seismic criteria together with LWD measurements. While covering drilling, geology and geophysics, most Well Placement approaches rarely consider reservoir engineering aspects.
Therefore the project objectives were to evaluate the impacts in the productivity generated by the geometrical changes in the trajectory through numerical reservoir simulation. The research work was then divided into two parts. The first one was the creation of a representative 3D synthetic reservoir model where numerical simulations were applied for each trajectory design. A detailed sensitivity analysis was made by comparing the results among the different trajectory cases in order to identify the relationship between well positioning and its productivity response.
The second part consisted of a real geosteering case study. Around both planned and executed wellbores, it was created a detailed reservoir model enhanced by LWD inputs. To increase prediction accuracy, a refined gridding with variable cell size technique was applied to enhance pressure and saturation sensitivity. The level of precision was improved by using LWD measurements, such as the most precise formation pressure, the permeability near wellbore and the remote boundary mapper technology that provided a detailed reservoir structure based on formation resistivity contrast. Afterwards, reservoir simulations were performed in order to evaluate the impacts caused by the trajectory variations, demonstrating the expected productivity results versus the actual ones.
The work delivers a novel ability to construct optimal horizontal wells not only by including conventional Well Placement technique, using geological and geophysical criteria, but also by adding into the workflow an advanced numerical simulation approach. Such integration allows the operator to predict the impacts on the productivity as the trajectory is being changed, and the actual reservoir geometry and its properties are determined by LWD measurements. It also reinforces that predictions related to reservoir productivity should not only be performed on planning stage, but most importantly during or right after well execution using relevant inputs, such as the actual well path, LWD logs, and formation pressure measurements, which all combined provides an enhanced reservoir model, and so a more accurate forecast analysis.
Characteristics of Gas/Water/Viscous Oil in Stratified-Annular Horizontal Pipe Flows
Authors: Shmueli A. , Unander T. E. , Nydal O. J. 
Published: October 2015

In this paper, the characteristics of stratified-annular flows such as flow patterns, phase distributions, liquid height, and pressure gradient were studied using a traversing two-energy gamma densitometer, high-speed video recordings and pressure transducers.
The experiments were carried out in a 0.069m diameter and 50 m long horizontal pipe. The fluid system consist of high density gas, SF6, at 0.7 MPa and 20 C (46 kg/m3) to simulate high pressure conditions of real multiphase transport systems; 0.102 Pa s viscosity oil and water as liquid phases. Two-phase and three-phase flow experiments were conducted at four liquid superficial velocities and different gas velocities for water cut values (The water cut is defined as the ratio between the superficial water velocity to the liquid superficial velocity).
The experimental results show that: The liquid fraction profile with a pure gas-oil shows higher values than for the three-phase flow profiles; the oil and water holdup profiles show water accumulation with respect of no-slip conditions due to more oil than water being entrained as droplets into the gas core; the three-phase pressure drop values are in between the gas-oil and gas-water values; when a comparison between the visual liquid heights with holdup measurements is made, there are indications that the shape of the gas-liquid interface may be curved. The application of gamma densitometry for measuring phase fractions in three-phase flows is shown and new data for systems using high viscosity oils for stratified-annular flows in horizontal pipes which is valuable for improving models and closures in multiphase flow simulators.
Study of Progressive Collapse of a Flare Boom Structure
Authors: Nabuco B. , Castanheira F. 
Published: October 2015

Topside structures in offshore installations are subjected to deterioration mechanisms such as corrosion and fatigue. One of the topside structures more prone to deterioration by corrosion is the flare boom due to the combination of corrosive marine environment with cycles of high temperatures.
This paper presents a structural reassessment of an existing flare boom structure under operation in a floating unit through a non-linear progressive collapse analysis.
A traditional linear analysis was not considered since the original design criteria are not met in the presence of these damages and the results are inconclusive with respect to structural integrity. Therefore, it was decided to perform a progressive collapse analysis (nonlinear) where the loads are applied incrementally in the light of a LRFD methodology. In this way, the structural stiffness matrix is updated in each load step while loads are redistributed due to both large deflections and materials non-linearity. The variation (loss) of the mechanical properties with respect to the temperature field was also taken into account.
This reassessment has considered, in addition to all design loads, several structural damages scenarios covering general and local corrosion. Since the actual corrosion pattern is not completely known due to the lack of inspection data, the definition of these assumed scenarios was necessary in order to investigate the global structural response in the presence of typical corrosion damages.
Members buckling, yielding/plastification, joint failure and global collapse results have been evaluated for ULS conditions in which it could be observed that gravitational loads governs the structural collapse. SLS conditions have also been assessed in order to evaluate deflection results.
Finally, the results allow identifying the most critical members of the flare boom with respect to structural integrity giving to the Operator a rational way to prioritize them for inspection purposes. Following this procedure, the most important members with respect to global structural integrity are then known. In other words, more conclusive results regarding the structural integrity in the presence of damages will be assessed.
Advanced Microemulsion Cleaner Fluid Applications in Deepwater Wells
Authors: Quintero Lirio , Passanha Wallan D. , Aubry Eric , Poitrenaud Hugues 
Published: October 2015

In a high number of deepwater fields, water injector and producer wells are being drilled with synthetic or oil-based drilling fluid (SBM or OBM). The filter cake and drilling fluids residue left on all of the well surfaces after the drilling phase is a water-impermeable layer. If not removed, they will compromise project objectives. To avoid excessive operating costs and to remove near-wellbore damage, a quick and efficient removal of SBM or OBM with properly-designed clean-up fluids, such as microemulsion fluids, is required.
Properly designed microemulsion spacer fluid formulations can be used to displace the SBM or OBM to a water-based fluid and completely water-wet all the surfaces in less than one circulation. The displacement fluids are formulated with customized surfactant blends (CSB) that exhibit equal affinity for the oil and water phases. They promote a very thorough microemulsification of the oil residue from the SBM or OBM during the displacement operation resulting in an aqueous external phase at the end of the process. The microemulsion displacement fluids are formulated to: (a) prevent viscous sludge at the fluids interface; (b) remove all of the oil from the surfaces; and (c) make the wellbore surfaces and near- wellbore region water-wet.
In addition to spacer fluid formulations, customized microemulsion fluids can remediate wells and increase water injectivity and well productivity. These fluids contain a customized surfactant blend (CSB), a small amount of acid, and an optional co-surfactant. They form an in-situ microemulsion and produce a uniform wellbore cleanup in horizontal and highly-deviated open-hole wells. Customized microemulsion fluids are able to cleanup in a broad range of temperature, density, and salinity. They restore the water-wet condition of the rock and increase injectivity or productivity of the wells.
This paper presents laboratory evaluations and field data of treatment fluids for wellbore displacement and near-wellbore cleanup based on the microemulsification mechanism. Data from systematic evaluation tests performed prior to field application (e.g. interfacial tension, detergency tests, fluids compatibility, filter cake removal and regain permeability) demonstrates performance results that were beyond the capabilities of conventional treatments.
Based on the key performance indicators (turbidity of completion brine, volume used and resulting cleanliness of tools), displacement of SBM or OBM with microemulsion cleaners in deepwater applications was achieved in one circulation during the wellbore displacement process.
Successful removal of SBM or OBM in the near wellbore region is evidenced by comparing predicted and achieved injection and production rates.
Influence of climate model variability on projected Arctic shipping futures
Authors: Stephenson Scott R. , Smith Laurence C. 
Published: October 2015

AbstractThough climate models exhibit broadly similar agreement on key long‐term trends, they have significant temporal and spatial differences due to intermodel variability. Such variability should be considered when using climate models to project the future marine Arctic. Here we present multiple scenarios of 21st‐century Arctic marine access as driven by sea ice output from 10 CMIP5 models known to represent well the historical trend and climatology of Arctic sea ice. Optimal vessel transits from North America and Europe to the Bering Strait are estimated for two periods representing early‐century (2011–2035) and mid‐century (2036–2060) conditions under two forcing scenarios (RCP 4.5/8.5), assuming Polar Class 6 and open‐water vessels with medium and no ice‐breaking capability, respectively. Results illustrate that projected shipping viability of the Northern Sea Route (NSR) and Northwest Passage (NWP) depends critically on model choice. The eastern Arctic will remain the most reliably accessible marine space for trans‐Arctic shipping by mid‐century, while outcomes for the NWP are particularly model‐dependent. Omitting three models (GFDL‐CM3, MIROC‐ESM‐CHEM, and MPI‐ESM‐MR), our results would indicate minimal NWP potential even for routes from North America. Furthermore, the relative importance of the NSR will diminish over time as the number of viable central Arctic routes increases gradually toward mid‐century. Compared to vessel class, climate forcing plays a minor role. These findings reveal the importance of model choice in devising projections for strategic planning by governments, environmental agencies, and the global maritime industry.
Optimization of end‐members used in multiple linear regression geochemical mixing models
Authors: Dunlea Ann G. , Murray Richard W. 
Published: October 2015

AbstractTracking marine sediment provenance (e.g., of dust, ash, hydrothermal material, etc.) provides insight into contemporary ocean processes and helps construct paleoceanographic records. In a simple system with only a few end‐members that can be easily quantified by a unique chemical or isotopic signal, chemical ratios and normative calculations can help quantify the flux of sediment from the few sources. In a more complex system (e.g., each element comes from multiple sources), more sophisticated mixing models are required. MATLAB codes published in Pisias et al. () solidified the foundation for application of a Constrained Least Squares (CLS) multiple linear regression technique that can use many elements and several end‐members in a mixing model. However, rigorous sensitivity testing to check the robustness of the CLS model is time and labor intensive. MATLAB codes provided in this paper reduce the time and labor involved and facilitate finding a robust and stable CLS model. By quickly comparing the goodness of fit between thousands of different end‐member combinations, users are able to identify trends in the results that reveal the CLS solution uniqueness and the end‐member composition precision required for a good fit. Users can also rapidly check that they have the appropriate number and type of end‐members in their model. In the end, these codes improve the user's confidence that the final CLS model(s) they select are the most reliable solutions. These advantages are demonstrated by application of the codes in two case studies of well‐studied datasets (Nazca Plate and South Pacific Gyre).
Electromagnetic neutrinos in laboratory experiments and astrophysics
Authors: Giunti Carlo , Kouzakov Konstantin A. , Li Yu‐Feng , Lokhov Alexey V. , Studenikin Alexander I. , Zhou Shun 
Published: October 2015

An overview of neutrino electromagnetic properties, which open a door to the new physics beyond the Standard Model, is given. The effects of neutrino electromagnetic interactions both in terrestrial experiments and in astrophysical environments are discussed. The experimental bounds on neutrino electromagnetic characteristics are summarized. Future astrophysical probes of electromagnetic neutrinos are outlined.
image
Crystal Structure of the Isopropylzinc Alkoxide of Pyrimidyl Alkanol: Mechanistic Insights for Asymmetric Autocatalysis with Amplification of Enantiomeric Excess
Authors: Matsumoto Arimasa , Abe Takaaki , Hara Atsushi , Tobita Takayuki , Sasagawa Taisuke , Kawasaki Tsuneomi , Soai Kenso 
Published: October 2015

AbstractAsymmetric amplification during self‐replication is a key feature that is used to explain the origin of homochirality. Asymmetric autocatalysis of pyrimidyl alkanol in the asymmetric addition of diisopropylzinc to pyrimidine‐5‐carbaldehyde is a unique example of this phenomenon. Crystallization of zinc alkoxides of this 5‐pyrimidyl alkanol and single‐crystal X‐ray diffraction analysis of the alkoxide crystals reveal the existence of tetramer or higher oligomer structures in this asymmetric autocatalytic system.
In Situ Microscopy and Spectroscopy Applied to Surfaces at Work
Authors: Han Hui‐Ling , Melaet Gérôme , Alayoglu Selim , Somorjai Gabor A. 
Published: October 2015

AbstractThe present review discusses the current state of the art microscopic and spectroscopic characterization techniques available to study surfaces and interfaces under working conditions. Microscopic techniques such as environmental transmission electron microscopy and in situ transmission electron microscopy are first discussed showing their applications in the field of nanomaterials and catalysis. Next sum frequency generation vibrational spectroscopy is discussed, giving probing examples of surface studies in gaseous conditions. Synchrotron based X‐ray techniques are also examined with a specific focus on ambient pressure X‐ray photoelectron and absorption techniques such as near and extended X‐ray absorption fine structure. Each of the techniques is evaluated, whilst the pros and cons are discussed in term of surface sensitivity, spatial resolution and/or time resolution. The second part of the articles is articulated around the future of in situ characterization, giving examples of the probable development of the discussed techniques as well as an introduction of emerging tools such as scanning transmission X‐ray microscopy, ptychography, and X‐ray photon correlation spectroscopy.
Core‐Scaffold‐Inspired Asymmetric Synthesis of Polysubstituted Chiral Hexahydropyridazines that Potently Inhibit Breast Cancer Cell Proliferation by Inducing Apoptosis
Authors: Leng Hai‐Jun , Peng Fu , Zingales Sarah , Huang Wei , Wang Biao , Zhao Qian , Zhou Rui , He Gu , Peng Cheng , Han Bo 
Published: October 2015

AbstractThe highly enantioselective preparation of pharmacologically interesting hexahydropyridazine derivatives based on a multicomponent cascade reaction is described. This one‐pot approach utilizes an organocatalytic Michael reaction followed by intermolecular α‐amination and intramolecular hemiaminalization to yield a chiral pyridazine backbone with contiguous stereogenic centers and multiple functional groups in good yield and with high stereoselectivity. Compounds synthesized by this method potently inhibited proliferation of MCF‐7 breast cancer cells. Mechanistic studies suggest that compound 5 c exerts these anticancer effects by inducing apoptosis through extracellular signal related kinase (ERK)‐ and poly(adenosine diphosphate ribose) polymerase (PARP)‐regulated pathways, as well as mitochondrial pathways.
Nature‐Inspired Multifunctional Ligands: Focusing on Amyloid‐Based Molecular Mechanisms of Alzheimer's Disease
Authors: Simoni Elena , Serafini Melania M. , Bartolini Manuela , Caporaso Roberta , Pinto Antonella , Necchi Daniela , Fiori Jessica , Andrisano Vincenza , Minarini Anna , Lanni Cristina , Rosini Michela 
Published: October 2015

AbstractThe amyloidogenic pathway is a prominent feature of Alzheimer's disease (AD). However, growing evidence suggests that a linear disease model based on β‐amyloid peptide (Aβ) alone is not likely to be realistic, which therefore calls for further investigations on the other actors involved in the play. The pro‐oxidant environment induced by Aβ in AD pathology is well established, and a correlation among Aβ, oxidative stress, and conformational changes in p53 has been suggested. In this study, we applied a multifunctional approach to identify allyl thioesters of variously substituted trans‐cinnamic acids for which the pharmacological profile was strategically tuned by hydroxy substituents on the aromatic moiety. Indeed, only catechol derivative 3 [(S)‐allyl (E)‐3‐(3,4‐dihydroxyphenyl)prop‐2‐enethioate] inhibited Aβ fibrilization. Conversely, albeit to different extents, all compounds were able to decrease the formation of reactive oxygen species in SH‐SY5Y neuroblastoma cells and to prevent alterations in the conformation of p53 and its activity mediated by soluble sub‐lethal concentrations of Aβ. This may support an involvement of oxidative stress in Aβ function, with p53 emerging as a potential mediator of their functional interplay.
Fit of cobalt–chromium implant frameworks before and after ceramic veneering in comparison with CNC‐milled titanium frameworks
Authors: Svanborg Per , Stenport Victoria , Eliasson Alf 
Published: October 2015

AbstractComputer‐aided design/computer‐aided manufacturing fabrication of implant‐supported frameworks is a standard procedure, and the use of ceramic‐veneered cobalt–chromium alloys is increasing. However, no data are available concerning the precision of fit of these frameworks and the impact on the fit of the veneering procedure. The aim of this study was to evaluate the fit of computer numeric‐controlled‐milled cobalt–chromium and titanium implant frameworks for edentulous maxillas, provided with six implants. An additional aim was to evaluate the effect of ceramic veneering on the fit of the cobalt–chromium frameworks. Ten stone casts simulating an edentulous maxilla provided with six dental implants and abutments were produced. One computer numeric‐controlled‐milled cobalt–chromium framework and one titanium framework were fabricated for each stone cast. Each stone cast and corresponding titanium and cobalt–chromium framework was measured with a coordinate measuring machine in the three‐dimensional (X axis, Y axis, and Z axis) directions. Both milled titanium and cobalt–chromium frameworks presented a good fit in the vertical plane (Z axis), 5.3 µm for titanium frameworks and 4.6 µm for the cobalt–chromium frameworks. The titanium frameworks showed a statistically significant smaller mean degree of misfit in the horizontal plane, X (5.0 µm) and Y (2.8 µm) axes as compared with the cobalt–chromium frameworks presenting a mean deviation of 13.5 µm in X axis and 6.3 µm in Y axis (P < 0.001). After ceramic veneering of the cobalt–chromium frameworks, the horizontal distortion significantly decreased from 13.5 to 9.7 µm in X axis (P = 0.007) and from 6.3 to 4.4 µm in Y axis (P = 0.017). The fit of both titanium and cobalt–chromium frameworks was very good. There were small but significant differences in fit between the titanium and cobalt–chromium frameworks, but the difference is of no clinical significance. The ceramic veneering resulted in a minor but significant improvement of the fit for the cobalt–chromium frameworks.
Carbon‐Free Cathodes: A Step Forward in the Development of Stable Lithium–Oxygen Batteries
Authors: Landa‐Medrano Imanol , Pinedo Ricardo , Ortiz‐Vitoriano Nagore , de Larramendi Idoia Ruiz , Rojo Teófilo 
Published: October 2015

AbstractLithium–oxygen (Li–O2) batteries are receiving considerable interest owing to their potential for higher energy densities than current Li–ion systems. However, the lack stability of carbon‐based oxygen electrodes is believed to promote carbonate formation leading to capacity fade and limiting the cycling performance of the battery. To improve the stability and cyclability of these systems, alternative electrode materials are required. Metal oxides are mainly utilized at low current densities, whereas noble metals show outstanding performance at high current densities. Carbides appear to provide a good compromise between electrochemical performance and cost, which makes them interesting materials for further investigations. Here, a critical review of current carbon‐free electrode research is provided with the goal of identifying routes to its successful optimization.