bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unconventional hydrocarbon resources: geological statistics, petrophysical characterization, and field development strategies
Authors: Muther Temoor , Qureshi Haris Ahmed , Syed Fahad Iqbal , Aziz Hassan , Siyal Amaar , Dahaghi Amirmasoud Kalantari , Negahban Shahin 
Published: December 2021

AbstractHydrocarbons exist in abundant quantity beneath the earth's surface. These hydrocarbons are generally classified as conventional and unconventional hydrocarbons depending upon their nature, geology, and exploitation procedure. Since the conventional hydrocarbons are under the depletion phase, the unconventional hydrocarbons have been a major candidate for current and future hydrocarbon production. Additionally, investment and research have increased significantly for its exploitation. Having the shift toward unconventional hydrocarbons, this study reviews in depth the technical aspects of unconventional hydrocarbons. This review brings together all the important aspects of unconventional reservoirs in single literature. This review at first highlights the worldwide unconventional hydrocarbon resources, their technical concept, distribution, and future supplies. A portion of this study also discusses the resources of progressive unconventional hydrocarbon candidates. Apart from this, this review also highlights the geological aspects of different unconventional hydrocarbon resources including tight, shale, and coalbed methane. The petrophysical behavior of such assists including the response to well logs and the discussion of improved correlation for petrophysical analysis is a significant part of this detailed study. The variation in geology and petrophysics of unconventional resources with conventional resources are also presented. In addition, the latest technologies for producing unconventional hydrocarbons ranging from fractured wells to different fluid injections are discussed in this study. In the end, the latest machine learning and optimization techniques have been discussed that aids in the optimized field development planning of unconventional reservoirs.
Synthesis, characterization and evaluation of stearyl acrylate-co-behenyl acrylate copolymer as a pour point depressant of waxy crude oil
Authors: Elarbe Basem , Elganidi Ibrahim , Ridzuan Norida , Yusoh Kamal , Abdullah Norhayati , Vijayakumar Shamala 
Published: December 2021

AbstractPour point depressant (PPD) has the competitive advantage of lowering the temperature of the wax appearance (WAT) and crude oil viscosity. In this paper, a novel PPD of poly stearyl acrylate-co-behenyl acrylate (SA-co-BA) in various mass ratios (1:1, 2:1, 3:1, 1:2 and 1:3) was effectively synthesized by solution radical polymerization method, and characterized by fourier transform infrared FTIR, proton nuclear magnetic resonance NMR, x-ray diffraction XRD and scanning electron microscopy SEM. The SA-co-BA PPD was evaluated on Malaysian crude oil via the pour point, the rheological and cold finger analysis to prevent the wax deposition at low temperature and improve flowability. The findings showed that the mass ratio (1:1) at 1000 ppm has a positive effect on the pour point depression from 11 to 2 °C. It was investigated from the rheological measurement that the viscosity of crude oil increases as the temperature decreases. Whereas, the viscosity decreases as the shear rate increases and as shear rate increases, shear stress increases. The flowability performance of the crude by the mass ratio of 1:1 at 1000 of the SA-co-BA concentrations have improved by 89.76%. The highest paraffin inhibition efficiency PIE of wax deposited was obtained at 1:1 of the mass ratio by 44.14%, indicating the smallest amount of wax is formed. This finding is interestingly attributed to the acrylate groups that have a long alkyl chain. Thus, SA-co-BA copolymer was demonstrated to be an appreciable pour point depressant that can prevent the wax deposition at low temperature and increasing the flowability of Malaysian crude oil.
Inaccuracy in arc power calculation through a product of voltage and current averages
Authors: Scotti Américo , Batista Márcio Andrade , Eshagh Mehdi 
Published: December 2021

AbstractPower is an indirect measurand, determined by processing voltage and current analogue signals through calculations. Using arc welding as a case study, the objective of this work was to bring up subsidies for power calculation. Based on the definitions of correlation and covariance in statistics, a mathematical demonstration was developed to point out the difference between the product of two averages (e.g. P = $$\overline{U} x \overline{I}$$

U
¯

x

I
¯

) and the average of the products (e.g. P = ($$\overline{UxI}$$

UxI

¯

). Complementarily, a brief on U and I waveform distortion sources were discussed, emphasising the difference between signal standard deviations and measurement errors. It was demonstrated that the product of two averages is not the same as the average of the products, unless in specific conditions (when the variables are fully correlated). It was concluded that the statistical correlation can easily flag the interrelation, but if assisted by covariance, these statistics quantify the inaccuracy between approaches. Finally, although the statistics' determination is easy to implement, it is proposed that power should always be calculated as the average of the instantaneous U and I products. It is also proposed that measurement error sources should be observed and mitigated, since they predictably interfere in power calculation accuracy.
Randomized Clinical Trial Comparing Dialogical Family Guidance with Ordinary Clinical Treatment for Families with a Child with Neurodevelopmental Disorders
Authors: Cavonius-Rintahaka Diana , Roos Mervi , Gillberg Christopher , Billstedt Eva , Aho Anna Liisa 
Published: December 2021

Abstract
Objectives
Previous studies have highlighted the need to offer targeted interventions to strengthen the wellbeing of family members in families with children with neurodevelopmental disorders (NDD). Interventions for this target group require research and development. The purpose of this study was to test a new family intervention: Dialogical Family Guidance (DFG).

Methods
Families of children with NDD were randomized into an intervention group that was delivered DFG and a comparison group provided with ordinary clinical treatment. The Family Functioning, Family Health and Social Support (FAFHES) and the DFG instrument were used to collect data at baseline and after 3 months. Repeated measure analysis of variance (ANOVA) was used as an analytical strategy.

Results
There was a significant within-subjects effect of time on family health and social support, indicating that family health and social support increased in both groups over time. There was also a significant between-subjects effect of group and interaction between time and group on social support, indicating that social support increased more in the intervention group than in the control group. Managing in daily life and the relationship between parents were associated with family functioning and family health.

Conclusion
DFG can strengthen parental experiences of social support. Managing in daily life, relationship between parents, practical guidance, psychoeducation, dialogue, and receiving positive feedback on parenting were strengthening factors during DFG. However, the results of this study must be considered as only preliminary, as they relate only to parental perceptions of the intervention effects.

Trial registration
ClinicalTrials.gov NCT04892992 (retrospectively registered).
Orbital‐ and Millennial‐Scale Variability in Northwest African Dust Emissions Over the Past 67,000 years
Authors: Kinsley Christopher W. , Bradtmiller Louisa I. , McGee David , Galgay Michael , Stuut Jan‐Berend , Tjallingii Rik , Winckler Gisela , deMenocal Peter B. 
Published: December 2021

AbstractReconstructions of aeolian dust flux to West African margin sediments can be used to explore changing atmospheric circulation and hydroclimate over North Africa on millennial to orbital timescales. Here, we extend West African margin dust flux records back to 37 ka in a transect of sites from 19° to 27°N, and back to 67 ka at Ocean Drilling Program (ODP) Hole 658C, in order to explore the interplay of orbital and high‐latitude forcings on North African climate and make quantitative estimates of dust flux during the core of the Last Glacial Maximum (LGM). The ODP 658C record shows a Green Sahara interval from 60 to 50 ka during a time of high Northern Hemisphere summer insolation, with dust fluxes similar to levels during the early Holocene African Humid Period, and an abrupt peak in flux during Heinrich event 5a (H5a). Dust fluxes increase from 50 to 35 ka while the high‐latitude Northern Hemisphere cools, with peaks in dust flux associated with North Atlantic cool events. From 35 ka through the LGM dust deposition decreases in all cores, and little response is observed to low‐latitude insolation changes. Dust fluxes at sites from 21° to 27°N were near late Holocene levels during the LGM time slice, suggesting a more muted LGM response than observed from mid‐latitude dust sources. Records along the northwest African margin suggest important differences in wind responses during different stadials, with maximum dust flux anomalies centered south of 20°N during H1 and north of 20°N during the Younger Dryas.
Simulation of Unconfined Aquifer Flow Based on Parallel Adaptive Mesh Refinement
Authors: Kourakos Georgios , Harter Thomas 
Published: December 2021

AbstractThe density of a numerical mesh is a key component for the quality of the numerical solution. Common methods in groundwater simulations rely on meshes generated prior to simulation, which lead to unnecessary or insufficient degrees of freedom (dofs). In this study we use Adaptive Mesh Refinement (AMR) to substitute the subjective mesh generation process with a more rigorous approach where new dofs are iteratively added to the solution of an initial coarse mesh based on a solution error estimation. The simulation is solved on a succession of meshes through which the mesh density is increased in areas of steep gradients in the solution variable. Here, we apply the approach to unconfined aquifer flow which is a non‐linear problem commonly encountered in groundwater modeling. By taking advantage of the iterative nature of AMR we arrive at an efficient solver approach. We treat the position of the unconfined boundary as an additional unknown which is estimated iteratively. The first iterations are executed rapidly as the mesh is rather coarse, while the free boundary adapts to the computed water table position as close as the mesh density allows. In this study we demonstrate the viability of the proposed unconfined aquifer simulation method to a series of 2D hypothetical examples under several conditions and stresses as well as a 3D test case. In all cases the AMR was able to automatically resolve the solution in areas with steep hydraulic head gradient, using appropriately higher density to achieve high localized refinement and accuracy.
The Influence of Atmosphere‐Ocean Phenomenon on Water Availability Across Temperate Australia
Authors: Khaledi Jabbar , Nitschke Craig , Lane Patrick N. J. , Penman Trent , Nyman Petter 
Published: December 2021

AbstractLinks between climate variability modes, rainfall, and streamflow are important for understanding the trajectories of change and dynamics in water availability. In this study, we examined the influence of the El Nino Southern Oscillation, Indian Ocean Dipole, Southern Annular Mode, and Interdecadal Pacific Oscillation modes on interannual variations in rainfall and streamflow in four hydroclimate regions. We also explored the link between climate variability modes and extreme rainfall and streamflow years. Climate mode indices, rainfall, and streamflow data from 1975 to 2018 were analyzed for 92 predominately forested catchments located across temperate Australia. Climate modes had divergent influences on streamflow and rainfall between and within regions. Across temperate Australia, a higher proportion of interannual variation in rainfall was explained by climate modes than for streamflow, indicating factors other than atmosphere‐ocean phenomena are important in determining interannual streamflow variability. Extremes in rainfall and streamflow across regions were related to the co‐occurrence of climate modes, with a stronger relationship between teleconnections and low rainfall/streamflow years than high rainfall/streamflow years. The study provides new insights into the regional drivers of hydrological extremes and consolidates our understanding of the role of teleconnections on water availability in the temperate zone of Australia.
A New MEPED‐Based Precipitating Electron Data Set
Authors: Pettit Joshua M. , Randall Cora E. , Peck Ethan D. , Harvey V. Lynn 
Published: December 2021

AbstractThe work presented here introduces a new data set for inclusion of energetic electron precipitation (EEP) in climate model simulations. Measurements made by the medium energy proton and electron detector (MEPED) instruments onboard both the Polar Orbiting Environmental Satellites and the European Space Agency Meteorological Operational satellites are used to create global maps of precipitating electron fluxes. Unlike most previous data sets, the electron fluxes are computed using both the 0° and 90° MEPED detectors. Conversion of observed, broadband electron count rates to differential spectral fluxes uses a linear combination of analytical functions instead of a single function. Two dimensional maps of electron spectral flux are created using Delaunay triangulation to account for the relatively sparse nature of the MEPED sampling. This improves on previous studies that use a 1D interpolation over magnetic local time or L‐shell zonal averaging of the MEPED data. A Whole Atmosphere Community Climate Model (WACCM) simulation of the southern hemisphere 2003 winter using the new precipitating electron data set is shown to agree more closely with observations of odd nitrogen than WACCM simulations using other MEPED‐based electron data sets. Simulated EEP‐induced odd nitrogen increases led to ozone losses of more than 15% in the polar stratosphere near 10 hPa in September of 2003.
Field‐Aligned Current During an Interval of BY‐Dominated Interplanetary‐Field; Modeled‐to‐Observed Comparisons
Authors: Carter J. A. , Samsonov A. A. , Milan S. E. , Branduardi‐Raymont G. , Ridley A. J. , Paxton L. J. , Anderson B. J. , Waters C. L. , Edwards T. 
Published: December 2021

AbstractWe model an interval of remarkable interplanetary magnetic field (IMF), for which we have a comprehensive set of observational data. This interval is associated with the arrival of an interplanetary coronal mass ejection. The solar wind densities at the time are particularly high and the IMF is primarily northward over many hours. This results in strong auroral emissions within the polar cap in a cusp spot, which we associate with lobe reconnection at the high‐latitude magnetopause. We also observe areas of upwards field‐aligned current (FAC) within the summer Northern Hemisphere polar cap that exhibit large current magnitudes. The model can reproduce the spatial distribution of the FACs well, even under changing conditions in the incoming IMF. Discrepancies exist between the modeled and observed current magnitudes. Notably, the winter Southern Hemisphere exhibits much lower current magnitudes overall. We also model a sharp transition of the location of magnetopause reconnection at the beginning of the interval, before the IMF remained northward for many hours. The reconnection location changed rapidly from a subsolar location at the low‐latitude magnetopause under southward IMF conditions, to a high‐latitude lobe reconnection location when the field is northward. This occurs during a fast rotation of the IMF at the shock front of a magnetic cloud.
The Structure of the Cusp Diamagnetic Cavity and Test Particle Energization in the GAMERA Global MHD Simulation
Authors: Burkholder B. L. , Nykyri K. , Ma X. , Sorathia K. , Michael A. , Otto A. , Merkin V. 
Published: December 2021

AbstractElectrons with energies ≥40 keV can be found at low density in many different regions of Earth's magnetosphere. A litany of fundamental questions in space physics have focused on the acceleration mechanism of these particles, given that the sources of plasma are the relatively cool ionosphere and solar wind (∼1–100s eV). Upgraded global solar wind‐magnetosphere simulations which can resolve mesoscale dynamics have the ability to enhance our understanding of these high energy particles. This is because the energization of particles often takes the form of a sequence of discrete steps, potentially occurring in different regions of the magnetosphere and due to both meso‐ and global‐scale processes. First, brief results are presented from the Grid Agnostic MHD for Extended Research Applications (GAMERA) global simulation on the structure of the cusp diamagnetic cavity for northward and southward IMF. Then, the Conservative Hamiltonian Integrator for Magnetospheric Particles (CHIMP) framework, with both guiding center and full Lorentz integrators, evolves necessary parameters such as the energy and pitch angle of electron test particles to investigate particle acceleration inside the cavity, as well as the ultimate fate of electrons accelerated inside the cavity. The simulation shows that particles can gain ≥ 10 keV inside the cavity and subsequently leak into the magnetosheath or onto dipolar field lines where they execute different types of bounce motion. The distribution of test particles initialized inside the cavity is compared with Magnetospheric Multi‐Scale (MMS) observations.
Magnetic Reconnection Inside Solar Wind Rotational Discontinuity During Its Interaction With the Quasi‐Perpendicular Bow Shock and Magnetosheath
Authors: Guo Zhifang , Lin Yu , Wang Xueyi , Du Aimin 
Published: December 2021

AbstractUsing a three‐dimensional global hybrid simulation, we investigate the formation and evolution of ion‐scale magnetic reconnection inside an interplanetary rotational discontinuity (RD) owing to its interaction with the quasi‐perpendicular (Q‐) bow shock and the magnetosphere. The interplanetary magnetic field (IMF) is initially predominantly northward, while it changes to purely southward across the RD. A significantly thinned RD current layer with a width ∼ ion skin depth and normal magnetic field is formed by a shock compression process as the RD interacts with the Q‐ shock. Magnetic reconnection thereupon takes place inside the thin RD current layer, where Hall magnetic and electric fields, reconnection electric field, and high‐speed ion outflow jets are identified. Simultaneously, flux ropes form with an extension of a few ion inertial lengths. As the RD is transmitted into the magnetosheath, multiple reconnection sites lead to the formation of longer flux ropes. Moreover, magnetosheath reconnection is also found at new reconnection sites inside the RD. No reconnection is found in the Q‐ shock alone outside the RD. The flux ropes propagate poleward and tailward in the magnetosheath. In addition, magnetopause reconnection takes place under the southward IMF on the sunward side of the RD after the RD passes through the magnetopause.
Constraints on Emission Source Locations of Methane Detected by Mars Science Laboratory
Authors: Viúdez‐Moreiras D. , Richardson M. I. , Newman C. E. 
Published: December 2021

AbstractThe Sample Analysis at Mars (SAM) instrument on the Mars Science Laboratory (MSL) Curiosity rover has detected both methane spikes and variable background methane abundance in recent years in Gale Crater, Mars. While methane spikes have been attributed to a hypothetical local or regional source emission, the background measurements acquired during the nighttime were postulated to represent the global methane abundance on Mars. However, recent high‐accuracy observations by instruments on the Trace Gas Orbiter (TGO) in several locations around the planet have not detected methane at all, apparently contradicting the SAM measurements. This paper analyzes the constraints that TGO and MSL impose on the hypothetical location of the emission source of methane responsible for the levels detected by SAM. The numerical simulations presented here indicate that not only the spikes but also the background measurements performed by MSL must result from localized emissions, specifically in the northwest interior of Gale Crater. Other simulated emission source locations at a greater distance from MSL, even if still within Gale Crater, are difficult to reconcile with current observations by MSL and TGO. Confirming previous studies, these results therefore point either to an improbable scenario, in which the rover has landed close to one of only a few localized emission sources on Mars, or to a problematic scenario, in which an unknown loss mechanism must be invoked that is able to destroy methane orders of magnitude faster than predicted by standard gas chemistry or to a weighted action between both scenarios.
Isotopic Composition of CO2 in the Atmosphere of Mars: Fractionation by Diffusive Separation Observed by the ExoMars Trace Gas Orbiter
Authors: Alday Juan , Wilson Colin F. , Irwin Patrick G. J. , Trokhimovskiy Alexander , Montmessin Franck , Fedorova Anna A. , Belyaev Denis A. , Olsen Kevin S. , Korablev O. , Lefèvre Franck , Braude Ashwin S. , Baggio Lucio , Patrakeev Andrey , Shakun Alexey 
Published: December 2021

AbstractIsotopic ratios in atmospheric CO2 are shaped by various processes throughout Mars' history, and can help understand what the atmosphere of early Mars was like to sustain liquid water on its surface. In this study, we monitor the O and C isotopic composition of CO2 between 70 and 130 km for more than half a Martian year using solar occultation observations by the Atmospheric Chemistry Suite onboard the ExoMars Trace Gas Orbiter. We find the vertical trends of the isotopic ratios to be consistent with the expectations from diffusive separation above the homopause, with average values below this altitude being consistent with Earth‐like fractionation (δ13C = −3 ± 37‰; δ18O = −29 ± 38‰; and δ17O = −11 ± 41‰). Using these measurements, we estimate that at least 20%–40% of primordial C on Mars has escaped to space throughout history. The total amount of C lost from the atmosphere is likely to be well in excess of this lower limit, due to carbonate formation and further sink processes. In addition, we propose a photochemical transfer of light O from H2O to CO2 to explain the larger enrichment in the ratio in H2O than in CO2.