bluuebunny/crossref_metadata_2025 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.
Improving BOP Reliability Through an Integrated Management Approach
Authors: Martins F. B. , Bittencourt J. , Santos M. S. , Amato T. M.
Published: October 2015

The Oil & Gas Industry faces major challenges in seeking to improve the management of its exploration operations, mainly in terms of operational safety, process safety, preservation of environment and reliability of their equipment. The sensibility created by the theme BOP, due by all attention gathered after Macondo event, established a new level of requirements from regulatory agencies and clients themselves. Queiroz GalvÃo óleo e Gás S/A (QGOG), hence since 1981 with continuous operations of drilling services in Brazil, through a strategic reasoning aligned with the strengthening of quality management, safety, and environment, developed a program aiming to increase the reliability of BOP system and operational safety. The paper aims to demonstrate how the endeavor was conducted under this Program, making the initiative an unequaled experience.
Characterization and Adsorption Investigations of the Nanostructure of Gas Shales
Authors: Holmes Randall , Rupp Erik C. , Vishal Vikram , Wilcox Jennifer
Published: October 2015

Due to the complexities involved in the analysis of micro- and mesoporous gas shale, a combined theoretical and experimental approach has proven to provide increased insight into the adsorption characteristics of methane (CH4) and carbon dioxide (CO2). Pore characterization techniques are used to provide information for theoretical modeling efforts, such as pore volume and pore size distribution (PSD). Idealized powdered shale sorption isotherms are created by varying incremental amounts of kerogen, illite, quartz, and calcium carbonate (CaCO3). The kerogen and illite have been shown to be the most vital for micropore measurements. The kerogen was obtained from Silurian shale, while Green River illite was used for the clay component and the rest was composed of equal parts by weight of silica (SiO2) to represent quartz and CaCO3 to represent the carbonate components. Baltic, Eagle Ford, and Barnett shale sorption measurements were used to validate the idealized samples. The idealized and validation shale sorption isotherms were measured using low-pressure N2(77K), Ar (87K) and CO2 (273K) adsorbates on a Quantachrome Autosorb IQ2 instrument. A subset of these samples was also measured using CO2 and CH4 adsorbates under subsurface temperature and pressure conditions using a Rubotherm magnetic suspension balance. The shale samples were processed using outgassing temperatures that did not affect the structures of kerogen and illite, while removing adsorbed gas species, such as H2O and CH4. This data lends itself toward the development of predictive models weighted and scaled by the percentages of these essential shale components to provide accurate gas-in-pace estimates of both CH4 and CO2.
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.
The Influence of Compressibility and Shrinkage in the Start-up of a Flow of Gelled Waxy Crudes in Pipelines
Authors: Van Der Geest C. , Bizotto Guersoni V. C. , Merino-Garcia D. , Bannwart A. C.
Published: October 2015

The procedure of shutdown and restart of an oil production unit due to equipment maintenance or emergency occurs regularly during its operational lifetime. In some cases, the concentration of high molecular weight linear alkanes is very high, leading to the appearance of solids when the oil is cooled below a threshold temperature termed WAT (Wax Appearance Temperature). In such cases, the crude is typically called Waxy Oil, which requires a minimum temperature-dependent yield stress to start flowing. When designing the pipelines and the pump facilities engineers usually do a simplified force balance. The assumption is that when the pressure is enough to overcome the yield stress, flow restart occurs. However, there is considerable evidence that this calculation is overestimated, and therefore, a better understanding of the phenomena involved in this process is required. The present study was performed with two commercial waxy crudes, to better generalize the results. The first part of the study consisted of bench experiments to verify whether the crudes exhibit an yield stress. After we confirmed the presence of this rheological feature, we designed and built an experimental apparatus to verify how much pressure was required and how the pressure propagates through the gelled crude. The experimental data obtained confirms the evidence that the rheology might not be the dominant phenomenon in the restart. It actually indicates that compressibility and shrinkage can influence the necessary pressure to restart the flow as much as rheology or even more. We ran three different experimental procedures to evaluate the influence of shrinkage and compressibility separately, and in all of them we did not observed a real influence of the oil's rheology.
Reservoir-Schedule Coupled Uncertainty Analysis for PD Projects: Optimization Opportunities and Improvements for More Robust Production Forecasts
Authors: Silva V. C. , Pinto J. W.
Published: October 2015

In a production development project (PDP) many disciplines work, arising with a set of inherent uncertainties, which are quantifiable or not. A well-represented set of these uncertainties should lead to a realistic stochastic spectrum of production forecast, however only a part of these uncertainties is usually consider in the process. This paper presents an integrative proposal between different uncertainty areas inherent in a DP project, from the association of reservoir and activities schedule, driving to more accurate assessment of the probability spectrum and production-curve-based schedules optimization opportunities, assisting the decision making process. It was noticed that the impact on production forecasts may be significant when the uncertainties in the schedules are evaluated together with the reservoir uncertainties, especially in the short term. Moreover, the opportunities identified when reservoir and schedules are assessed combined can lead to a significant improvement in production forecasts and indicates flexibility and robustness gains.
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.
Resultado de un programa adaptado de ejercicio físico en pacientes ancianos en hemodiálisis
Authors: Junqué Jiménez Anna , Esteve Simón Vicent , Tomás Bernabeu Esther , Paz López Oscar , Iza Pinedo Gorka , Luceño Solé Inés , Lavado Sempere Mª Luisa , Ramírez de Arellano Manel
Published: October 2015

Introducción: Los pacientes ancianos constituyen un grupo en continuo crecimiento en los programas de hemodiálisis. Éstos se caracterizan por su elevada complejidad, dependencia y comorbilidad asociada. Múltiples beneficios del ejercicio físico en los pacientes en hemodiálisis han sido descritos; si bien no han sido completamente evaluados en la población anciana en hemodiálisis.
Objetivos: Analizar el efecto de un programa adaptado de ejercicio físico intradiálisis sobre la fuerza muscular, la capacidad funcional, la sintomatología depresiva y la calidad de vida en nuestros pacientes ancianos (>75 años) en hemodiálisis.
Material y métodos: Estudio prospectivo de 12 semanas de duración. 11 pacientes incluidos (36.4% hombres). Edad media 83.9 años y 37.2 meses en hemodiálisis. Charlson medio: 9.7. Principal etiología: Diabetes Mellitus (45.5%), No filiada (27.3%), hipertensión (9.1%). Los pacientes incluidos realizaron un programa de ejercicio físico adaptado mediante pelotas medicinales, pesas, bandas elásticas y cicloergómetros en las primeras dos horas de hemodiálisis. Analizamos: 1.-Parámetros bioquímicos. 2. Datos musculares: Fuerza extensión máxima cuádriceps y hand-grip. 3.-Tests Test funcionales: "Sit to stand to sit" y "six-minutes walking test". 4.- Sintomatología depresiva: Inventario Beck. 5.-Calidad de Vida: EuroQol-5D.
Resultados: De forma global, se observó una mejoría en las pruebas realizadas (*p
Black carbon surface oxidation and organic composition of beech-wood soot aerosols
Authors: Corbin J. C. , Lohmann U. , Sierau B. , Keller A. , Burtscher H. , Mensah A. A.
Published: October 2015

Abstract. Soot particles are the most strongly light-absorbing particles commonly found in the atmosphere. They are major contributors to the radiative budget of the Earth and to the toxicity of atmospheric pollution. Atmospheric aging of soot may change its health- and climate-relevant properties by oxidizing the primary black carbon (BC) or organic particulate matter (OM) which, together with ash, comprise soot. This atmospheric aging, which entails the condensation of secondary particulate matter as well as the oxidation of the primary OM and BC emissions, is currently poorly understood. In this study, atmospheric aging of wood-stove soot aerosols was simulated in a continuous-flow reactor. The composition of fresh and aged soot particles was measured in real time by a dual-vaporizer aerosol-particle mass spectrometer (SP-AMS). The dual-vaporizer SP-AMS provided information on the OM and BC components of the soot as well as on refractory components internally mixed with BC. By switching the SP-AMS laser vaporizer off and using only the AMS thermal vaporizer (at 600 °C), information on the OM component only was obtained. In both modes, OM appeared to be generated largely by cellulose and/or hemicellulose pyrolysis and was only present in large amounts when new wood was added to the stove. In SP-AMS mode, BC signals otherwise dominated the mass spectrum. These signals consisted of ions related to refractory BC (rBC, C1-5+), oxygenated carbonaceous ions (CO1-2+), potassium (K+), and water (H2O+ and related fragments). The C4+ : C3+ ratio, but not the C1+ : C3+ ratio, was consistent with the BC-structure trends of Corbin et al. (2015c). The CO1-2+ signals likely originated from BC surface groups: upon aging, both CO+ and CO2+ increased relative to C1-3+ while CO2+ simultaneously increased relative to CO+. Factor analysis (positive matrix factorization) of SP-AMS and AMS data, using a modified error model to address peak-integration uncertainties, indicated that the surface composition of the BC was approximately constant across all stages of combustion for both fresh and aged samples. These results represent the first time-resolved measurements of in situ BC surface aging and suggest that the surface of beech-wood BC may be modelled as a single chemical species.
Optimization of a gas sampling system for measuring eddy-covariance fluxes of H2O and CO2
Authors: Metzger S. , Burba G. , Burns S. P. , Blanken P. D. , Li J. , Luo H. , Zulueta R. C.
Published: October 2015

Abstract. Several initiatives are currently emerging to observe the exchange of energy and matter between the earth's surface and atmosphere standardized over larger space and time domains. For example, the National Ecological Observatory Network (NEON) and the Integrated Carbon Observing System (ICOS) will provide the ability of unbiased ecological inference across eco-climatic zones and decades by deploying highly scalable and robust instruments and data processing. In the construction of these observatories, enclosed infrared gas analysers are widely employed for eddy-covariance applications. While these sensors represent a substantial improvement compared to their open- and closed-path predecessors, remaining high-frequency attenuation varies with site properties, and requires correction. Here, we show that the gas sampling system substantially contributes to high-frequency attenuation, which can be minimized by careful design. From laboratory tests we determine the frequency at which signal attenuation reaches 50 % for individual parts of the gas sampling system. For different models of rain caps and particulate filters, this frequency falls into ranges of 2.5–16.5 Hz for CO2, 2.4–14.3 Hz for H2O, and 8.3–21.8 Hz for CO2, 1.4–19.9 Hz for H2O, respectively. A short and thin stainless steel intake tube was found to not limit frequency response, with 50 % attenuation occurring at frequencies well above 10 Hz for both H2O and CO2. From field tests we found that heating the intake tube and particulate filter continuously with 4 W was effective, and reduced the occurrence of problematic relative humidity levels (RH > 60 %) by 50 % in the infrared gas analyser cell. No further improvement of H2O frequency response was found for heating in excess of 4 W. These laboratory and field tests were reconciled using resistor-capacitor theory, and NEON's final gas sampling system was developed on this basis. The design consists of the stainless steel intake tube, a pleated mesh particulate filter, and a low-volume rain cap in combination with 4 W of heating and insulation. In comparison to the original design, this reduced the high-frequency attenuation for H2O by ≈ 3/4, and the remaining cospectral correction did not exceed 3 %, even at a very high relative humidity (95 %). This standardized design can be used across a wide range of eco-climates and site layouts, and maximizes practicability due to minimal flow resistance and maintenance needs. Furthermore, due to minimal high-frequency spectral loss, it supports the routine application of adaptive correction procedures, and enables more automated data processing across sites.
Retrieval of near-surface sulfur dioxide (SO2) concentrations at a global scale using IASI satellite observations
Authors: Bauduin S. , Clarisse L. , Hadji-Lazaro J. , Theys N. , Clerbaux C. , Coheur P.-F.
Published: October 2015

Abstract. SO2 from volcanic eruptions is now operationally monitored from space in both ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO2 has almost solely been measured from UV sounders. Indeed, TIR instruments are well-known to have a poor sensitivity to the boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability of the Infrared Atmospheric Sounding Interferometer (IASI) to measure near-surface SO2 locally, for specific atmospheric conditions. In this work, we develop a retrieval method allowing the inference of SO2 near-surface concentrations from IASI measurements at a global scale. This method consists of two steps. Both are based on the computation of radiance indexes representing the strength of the SO2 ν3 band in IASI spectra. The first step allows retrieving the peak altitude of SO2 and selecting near-surface SO2. In the second step, 0–4 km columns of SO2 are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface SO2 from IASI-A, and identify the dominant anthropogenic hotspot sources and volcanic degassing. The 7-year daily time evolution of SO2 columns above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran) is investigated and correlated to the seasonal variations of the parameters that drive the IASI sensitivity to the PBL composition. Apart from TC, we show that humidity is the most important parameter which determines IR sensitivity to near-surface SO2. As IASI provides twice daily global measurements, the differences between the retrieved columns for the morning and evening orbits are investigated. This paper finally presents a first intercomparison of the measured 0–4 km columns with an independent iterative retrieval method and with observations of the Ozone Monitoring Instrument (OMI).
Soil microbial nutrient constraints along a tropical forest elevation gradient: a belowground test of a biogeochemical paradigm
Authors: Nottingham A. T. , Turner B. L. , Whitaker J. , Ostle N. J. , McNamara N. P. , Bardgett R. D. , Salinas N. , Meir P.
Published: October 2015

Abstract. Aboveground primary productivity is widely considered to be limited by phosphorus (P) availability in lowland tropical forests and by nitrogen (N) availability in montane tropical forests. However, the extent to which this paradigm applies to belowground processes remains unresolved. We measured indices of soil microbial nutrient status in lowland, sub-montane and montane tropical forests along a natural gradient spanning 3400 m in elevation in the Peruvian Andes. With increasing elevation there were marked increases in soil concentrations of total N, total P, and readily exchangeable P, but a decrease in N mineralization determined by in situ resin bags. Microbial carbon (C) and N increased with increasing elevation, but microbial C : N : P ratios were relatively constant, suggesting homeostasis. The activity of hydrolytic enzymes, which are rich in N, decreased with increasing elevation, while the ratio of enzymes involved in the acquisition of N and P increased with increasing elevation, further indicating an increase in the relative demand for N compared to P with increasing elevation. We conclude that soil microorganisms shift investment in nutrient acquisition from P to N between lowland and montane tropical forests, suggesting that different nutrients regulate soil microbial metabolism and the soil carbon balance in these ecosystems.
CranSLIK v2.0: improving the stochastic prediction of oil spill transport and fate using approximation methods
Authors: Rutherford R. , Moulitsas I. , Snow B. J. , Kolios A. J. , De Dominicis M.
Published: October 2015

Abstract. Oil spill models are used to forecast the transport and fate of oil after it has been released. CranSLIK is a model that predicts the movement and spread of a surface oil spill at sea via a stochastic approach. The aim of this work is to identify parameters that can further improve the forecasting algorithms and expand the functionality of CranSLIK, while maintaining the run-time efficiency of the method. The results from multiple simulations performed using the operational, validated oil spill model, MEDSLIK-II, were analysed using multiple regression in order to identify improvements which could be incorporated into CranSLIK. This has led to a revised model, namely CranSLIK v2.0, which was validated against MEDSLIK-II forecasts for real oil spill cases. The new version of CranSLIK demonstrated significant forecasting improvements by capturing the oil spill accurately in real validation cases and also proved capable of simulating a broader range of oil spill scenarios.
On the modulation of the periodicity of the Faroe Bank Channel overflow instabilities
Authors: Darelius E. , Fer I. , Rasmussen T. , Guo C. , Larsen K. M. H.
Published: October 2015

Abstract. The Faroe Bank Channel (FBC) is one of the major pathways where dense, cold water formed in the Nordic Seas flows southward as a bottom-attached energetic plume towards the North Atlantic. The plume region downstream of the FBC sill is characterized by high mesoscale variability, quasi-regular oscillations and intense mixing. Here, 1 year long time series of velocity and temperature from ten moorings deployed in May 2012 in the plume region are analysed to describe variability in the strength and period of the oscillations. The eddy kinetic energy (EKE) associated with the oscillations changes by a factor of 10 during the year and the dominant period of the oscillations is modulated and varies between 3 to 4 and 6 days, where the shorter-period oscillations are more energetic. The dense water is observed on a wider portion of the slope (both deeper and shallower) during periods with energetic, short-period oscillations. The observations are complemented by results from a regional, high-resolution model that shows a similar variability in EKE and a gradual change in oscillation period of between 3 and 4 days. The observed variability in oscillation period is directly linked to changes in the volume transport across the sill: the oscillation period increases from approximately 3 days to about 6 days when the transport decreases from 2.4 to 1.9 Sv. A similar relation is obtained from the model. This is in agreement with results from a linear baroclinic instability analysis, which suggests that the period increases while the growth rate decreases for decreased plume thickness. Advective effects, caused by the variable background current, further modulate the observed periodicity by up to 1 day. In addition, it is shown that about 50 % of the transport variability across the sill is explained by changes in the local sea surface height gradient.
A conceptual affective design framework for the use of emotions in computer game design
Authors: De Byl Penny
Published: October 2015

The purpose of this strategy of inquiry is to understand how emotions influence gameplay and to review contemporary techniques to design for them in the aim of devising a model that brings current disparate parts of the game design process together. Emotions sit at the heart of a game player’s level of engagement. They are evoked across many of the components that facilitate gameplay including the interface, the player’s avatar, non-player characters and narrative. Understanding the role of emotion in creating truly immersive and believable environments is critical for game designers. After discussing a taxonomy of emotion, this paper will present a systematic literature review of designing for emotion in computer games. Following this, a conceptual framework for affective design is offered as a guide for the future of computer game design.
Getting Past the “Yuck Factor”: Public Opinion Research Provides Guidance for Successful Potable Reuse Outreach
Authors: Tennyson Patricia A. , Millan Mark , Metz David
Published: October 2015

Leveraging the right research, terminology, and tools can make all the difference in successfully garnering public support for potable reuse water.
The Cost of Borrowing: Understanding Credit Ratings
Authors: Warmath Alexis , Kreps Bart
Published: October 2015

With more than $1 trillion in infrastructure investment needs over the next 25 years, many water, wastewater, and stormwater utilities across the United States will need continued access to the capital markets as a source for financing system improvements. And just as for someone borrowing money to buy a house, a utility's credit rating is a key component in determining its cost of debt or a creditor's required rate of return to compensate for the risk of lending money. Central to this discussion is the role that rating agencies play in evaluating credit. While credit ratings are not required in order to issue municipal securities, they provide a key benchmark and guidance to the market on the probability of default.
Influence of climate model variability on projected Arctic shipping futures
Authors: Stephenson Scott R. , Smith Laurence C.
Published: October 2015

Though 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

Tracking 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).
In Situ TEM Observation of Electrochemical Lithiation of Sulfur Confined within Inner Cylindrical Pores of Carbon Nanotubes
Authors: Kim Hyea , Lee Jung Tae , Magasinski Alexandre , Zhao Kejie , Liu Yang , Yushin Gleb
Published: October 2015

Lithium insertion into sulfur confined within 200 nm cylindrical inner pores of individual carbon nanotubes (CNTs) was monitored in situ in a transmission electron microscope (TEM). This electrochemical reaction was initiated at one end of the S‐filled CNTs. The material expansion during lithiation was accommodated by the expansion into the remaining empty pore volume and no fracture of the CNT walls was detected. A sharp interface between the initial and lithiated S was observed. The reaction front was flat, oriented perpendicular to the confined S cylinder, and propagated along the cylinder length. Lithiation of S in the proximity of conductive carbon proceeded at the same rate as the one in the center of the pore, suggesting the presence of electron pathways at the Li2S/S interface. Density of states calculations further confirmed this hypothesis. In situ electron diffraction showed a direct phase transformation of S into nanocrystalline Li2S without detectable formation of any intermediates, such as polysulfides and LiS. These important insights may elucidate some of the reaction mechanisms and guide the improvements in the design of C–S nanocomposites for high specific energy Li–S batteries. The proposed use of conductive CNTs with tunable pore diameter as cylindrical reaction vessels for in situ TEM studies of electrochemical reactions proved to be highly advantageous and may help to resolve the ongoing problems in battery technology.
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

Asymmetric 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.
Flexible modelling of vaccine effect in self‐controlled case series models
Authors: Ghebremichael‐Weldeselassie Yonas , Whitaker Heather J. , Farrington C. Paddy
Published: October 2015

The self‐controlled case series (SCCS) method, commonly used to investigate the safety of vaccines, requires information on cases only and automatically controls all age‐independent multiplicative confounders, while allowing for an age‐dependent baseline incidence. Currently, the SCCS method represents the time‐varying exposures using step functions with pre‐determined cut points. A less prescriptive approach may be beneficial when the shape of the relative risk function associated with exposure is not known a priori, especially when exposure effects can be long‐lasting. We therefore propose to model exposure effects using flexible smooth functions. Specifically, we used a linear combination of cubic M‐splines which, in addition to giving plausible shapes, avoids the integral in the log‐likelihood function of the SCCS model. The methods, though developed specifically for vaccines, are applicable more widely. Simulations showed that the new approach generally performs better than the step function method. We applied the new method to two data sets, on febrile convulsion and exposure to MMR vaccine, and on fractures and thiazolidinedione use.
In Situ Microscopy and Spectroscopy Applied to Surfaces at Work
Authors: Han Hui‐Ling , Melaet Gérôme , Alayoglu Selim , Somorjai Gabor A.
Published: October 2015

The 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

The 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

The 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

Computer‐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.