bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influences of heating and plasma density on impurity production and transport during the ramp-down phase of JET ILW discharge
Authors: Ivanova-Stanik I , Zagórski R , Chomiczewska A , Lomas P J , Voitsekhovitch I , Ferreira D R , Sozzi C , Joffrin E , Lerche E 
Published: December 2020

Abstract
The aim of this paper is to study the influences of plasma heating and plasma density on impurity production and transport during the plasma-termination phase. We have analyzed the ramp-down (RD) phase of a set of representative high-current JET ITER-like wall discharges: #92 437 (disrupted) and #92 442 (soft landing), characterized by a high plasma current of I

p
= 3.5MA. Analysis is performed for different time slots within the RD phase, corresponding to different levels of electron line density and auxiliary heating power. Since the deuterium gas fluxes are different, the influence of the separatrix density is also analyzed. The main conclusion from the simulations is the observation that for the same average-electron density, a decrease of the separatrix density leads to an increase of the plasma temperature at the divertor plate, leading to increased W production and consequently to a larger W concentration and radiation in the core. When the central electron temperature approaches the 2 keV level, corresponding to the maximum W and Ni cooling rate, the radiation in the plasma’s center is enhanced. Ni radiation is more important in the RD phase.
Multiphase lattice metamaterials with enhanced mechanical performance
Authors: Usta Fatih , Scarpa Fabrizio , Türkmen Halit S , Johnson Peter , Perriman Adam W , Chen Yanyu 
Published: December 2020

Abstract
We describe here the quasi-static crushing behavior of novel classes of multiphase (hybrid) hierarchical lattice metamaterials. The first class is represented by a hybrid architecture combining a hierarchical honeycomb with polyurethane foam filler, while the second is a multiphase structure produced by injecting an alginate hydrogel into the hierarchical voids of the honeycomb metamaterial. Twelve different auxetic (i.e. negative Poisson’s ratio) and non-auxetic metamaterial architectures have been 3D printed and subjected to edgewise compression crushing loading. A parametric numerical analysis has been also performed using validated finite element models to identify best metamaterial architecture configurations. Configurations filled with the hydrogel showed a significant stabilization of the deformation mechanism during large deformation edgewise compression. The use of metamaterials designs with internal slots and round in the ribs also filled by polyurethane rigid semi-reticulated foam feature however significant increases in terms of specific stiffness, mean crushing force, strength and energy absorption. The enhancement is particularly evident for the hybrid lattice metamaterials auxetic configurations.
Speech-imagery-based brain–computer interface system using ear-EEG
Authors: Kaongoen Netiwit , Choi Jaehoon , Jo Sungho 
Published: December 2020

Abstract

Objective. This study investigates the efficacy of electroencephalography (EEG) centered around the user’s ears (ear-EEG) for a speech-imagery-based brain–computer interface (BCI) system. Approach. A wearable ear-EEG acquisition tool was developed and its performance was directly compared to that of a conventional 32-channel scalp-EEG setup in a multi-class speech imagery classification task. Riemannian tangent space projections of EEG covariance matrices were used as input features to a multi-layer extreme learning machine classifier. Ten subjects participated in an experiment consisting of six sessions spanning three days. The experiment involves imagining four speech commands (‘Left,’ ‘Right,’ ‘Forward,’ and ‘Go back’) and staying in a rest condition. Main results. The classification accuracy of our system is significantly above the chance level (20%). The classification result averaged across all ten subjects is 38.2% and 43.1% with a maximum (max) of 43.8% and 55.0% for ear-EEG and scalp-EEG, respectively. According to an analysis of variance, seven out of ten subjects show no significant difference between the performance of ear-EEG and scalp-EEG. Significance. To our knowledge, this is the first study that investigates the performance of ear-EEG in a speech-imagery-based BCI. The results indicate that ear-EEG has great potential as an alternative to the scalp-EEG acquisition method for speech-imagery monitoring. We believe that the merits and feasibility of both speech imagery and ear-EEG acquisition in the proposed system will accelerate the development of the BCI system for daily-life use.
Adequately reflecting the severity of tropical cyclones using the new Tropical Cyclone Severity Scale
Authors: Bloemendaal Nadia , de Moel Hans , Mol Jantsje M , Bosma Priscilla R M , Polen Amy N , Collins Jennifer M 
Published: December 2020

AbstractFor decades, meteorologists and governments have been warning communities in coastal areas for an imminent tropical cyclone (TC) using the Saffir-Simpson Hurricane Wind Scale (SSHWS). The SSHWS categorizes a TC based on its maximum wind speed, and is used in defining evacuation strategies and humanitarian response. However, the SSHWS considers only the wind hazard of a TC, whereas a TC can also cause severe conditions through its high storm surges and extreme rainfall, triggering coastal and inland flooding. Consequently, the SSHWS fails to mirror the TC’s total severity. This becomes evident when looking at past events such as Hurricane Harvey (2017), which was classified as a Tropical Storm while it caused widespread flooding in the Houston (TX) area, with precipitation totals exceeding 1.5 m. Without including storm surge and rainfall information, adequate risk communication with the SSHWS can be challenging, as the public can (mistakenly) perceive a low-category TC as a low-risk TC. To overcome this, we propose the new Tropical Cyclone Severity Scale (TCSS) that includes all three major TC hazards in its classification. The new scale preserves the categorization as used in the SSHWS, to maintain familiarity amongst the general public. In addition, we extend the scale with a Category 6, to support communication about the most extreme TCs with multiple hazards. The TCSS is designed to be applied on a local-scale, hereby supporting local-scale risk communication efforts and evacuation strategies prior to a TC landfall. The scale can be used for risk communication on both the total TC risk and on the categories of the separate hazards, which can be valuable especially in cases when one hazard is the predominant risk factor, such as excess rainfall triggering flooding.
Reply to comment on ‘The relativistic Aharonov–Bohm–Coulomb system with position-dependent mass’
Authors: Oliveira R R S , Filho A A Araújo , Maluf R V , Almeida C A S 
Published: December 2020

Abstract
It is shown that the results of our paper are correct, although the use of the chirality operator γ
5 = σ
1 in the paper is not correct, as fairly the authors of the comment stated.
Phase space theory for open quantum systems with local and collective dissipative processes
Authors: Merkel Konrad , Link Valentin , Luoma Kimmo , Strunz Walter T 
Published: December 2020

Abstract
In this article we investigate driven dissipative quantum dynamics of an ensemble of two-level systems given by a Markovian master equation with collective and local dissipators. Exploiting the permutation symmetry in our model, we employ a phase space approach for the solution of this equation in terms of a diagonal representation with respect to certain generalized spin coherent states. Remarkably, this allows to interpolate between mean field theory and finite system size in a formalism independent of Hilbert-space dimension. Moreover, in certain parameter regimes, the evolution equation for the corresponding quasiprobability distribution resembles a Fokker–Planck equation, which can be efficiently solved by stochastic calculus. Then, the dynamics can be seen as classical in the sense that no entanglement between the two-level systems is generated. Our results expose, utilize and promote techniques pioneered in the context of laser theory, which can be powerful tools to investigate problems of current theoretical and experimental interest.
Carbonate fine lithology prediction using amplitude attribute of PS-wave
Authors: Qiyan Chen , Hongqiu Wang , Jianhu Gao , Xin Guo 
Published: December 2020

Abstract
The Lower Permian Maokou Formation and Qixia Formation in central part of Sichuan Basin have huge natural gas exploration potential. For the Maokou Formation, there is argillaceous limestone in the limestone background, and thin dolomite reservoirs are developed. The ability to use conventional PP-wave data to predict lithology and dolomite reservoirs is insufficient. In PP-wave seismic section, the response of argillaceous limestone and dolomite in the limestone background is not obvious, which limits the prediction accuracy of lithology. Making full use of high-precision matched PP-wave and PS-wave seismic data, we find a special phenomenon in the Maokou Formation that PP-wave usually shows weak amplitude and poor continuity while PS-wave shows stronger amplitude and better continuity. Aimed at the particular phenomenon, through multi-wave seismic forward modelling, log lithology interpretation, cross plot of P-impedance with S-impedance and seismic section comparison of PP-wave and PS-wave, it is clear that the weak peak of PP-wave and strong peak of PS-wave reflects weak and subtle change in lithology, which shows the existence of argillaceous limestone in limestone background. And the gas-bearing dolomite reservoirs are characterized by low frequency and weak amplitude on PP-wave, while show weak peak feature on PS-wave. Compared with PP-wave, the favorable lithology (dolomite) distribution predicted by maximum peak amplitude of PS-wave is more consistent with reservoir distribution and origin of hydrothermal-karst-controlled dolomite. Result of lithology prediction by PS-wave is reasonable and reliable for Maokou Formation.
Geochemical characteristics and genesis of the Upper Paleozoic natural gas in Longdong area, Ordos Basin, NW China
Authors: Kong Qingfen , Kong Lingyin , Li Jianfeng 
Published: December 2020

Abstract
The Upper Paleozoic gases from the Longdong areas in the Ordos Basin are characterized by low contents of heavy hydrocarbon gases, the mean value of wetness as 2%, relatively heavy δ13C1(δ13C1 value -28.3‰), and large variations in δ13C2
+. The distribution pattern of carbon isotopic sequence of natural gas is mainly characterized by the abnormal light δ13C2
+ values and carbon isotopic reversal. According to the organic geochemical characteristics of natural gas and the development of gas-source rocks, the upper Paleozoic natural gas in Longdong area belongs to high mature and over-mature “coal-formed gas”. In theory, only the mixture of highly mature gas with extremely low contents of heavy hydrocarbon gases and a small amount of natural gas with higher contents and lighter carbon isotopic composition of heavy hydrocarbon gases can lead to the occurrence of abnormally light δ13C2
+ and the carbon isotope reversal between methane and ethane. The mixed gas is probably derived from the thermal cracking of a small amount of residual soluble organic matter in the gas-source rocks and reservoirs during the initial stage of the uplift movement at the end of Early Cretaceous. Key words: Ethane carbon isotope; Inverted sequence of carbon isotopic composition; Natural gas of high maturity; natural gas genesis; Ordos Basin.
Shale gas prospect of different source rock types from Early Maastrichtian Mamu Formation, Anambra Basin, Nigeria
Authors: Faboya O L , Sonibare O O , Abimbade S F , Liao Z W 
Published: December 2020

Abstract
The gas prospect of three identified source rock types from the Early Maastrichtian Mamu Formation of the Anambra Basin, Nigeria was evaluated by thermal simulation, followed by gas composition analyses of the generated hydrocarbons. The amounts of C1 and ΣC1-5 generated at the highest examined pyrolysis temperature of 480°C (Easy Ro of 3.27%) range from 3.52 to 32.00 ml/g rock and 4.08 to 43.44 ml/g rock, respectively. The sub-bituminous coal has the highest gaseous hydrocarbon generative potential up to late gas generation stage, followed by carbonaceous shale while shale has the least productive capacity. The recovery of gaseous hydrocarbons may be influenced by the ratio of TOC to clay content in all the source rocks. The gas dryness index indicates that the shale is the driest among the source rock types.
Study on gas yields and generation kinetics of a type I kerogen sample by open and confined pyrolysis
Authors: Liu Jinzhong , Weng Cui , Li Yong , Yang Xiao 
Published: December 2020

Abstract
A shale sample collected from the Neoproterozoic Xiamaling Formation in Xiahuayuan region, North China, was studied by a newly developed apparatus, Multiple-Gas Container Open Pyrolysis Devise, and data were compared with those from confined gold tube pyrolysis. This device is mainly composed by a pyrolysis heater and 15 gas containers, a whole heating process was divided into 15 time/temperature segments, gases generated in different temperature segments with carrier gas were temporarily conserved in their gas container correspondingly. When pyrolysis completed, gases in each container were introduced to a gas chromatography for analysis. Sample was heated from room temperature to 650 °C. Because oil generated from sample was removed by carrier gas immediately from heating area, oil cracking did not play an important role in gas generation. Maximum yield of methane is only 28.4% of that from confined gold tube pyrolysis. Trend of methane yield from open method is similar to that from confined method in EASY%Ro range from 0.58% to 1.80%, indicating that oil cracking in this maturity range is minor, but at higher temperature, gas yields produced in confined pyrolysis increased rapidly, much higher than those from closed method. Activation energies of methane generation from open method ranges from 53 to 72 kcal/mol, central value of C1, C2, C3 decline with their carbon number, showing a clear generating order that the gas with larger carbon number will be generated earlier. δ 13C of methane from open method is similar to that from confined method in EASY%Ro range from 0.58% to 2.2%; But in later pyrolysis stage, it is much heavier than that from confined method. δ 13C deviation of methane between open and confined methods provides a possible way to calculate proportion of the gas from oil cracking. This open pyrolysis device offers a convenient and efficient way to simulate gas generation potential and acquire kinetics parameters, especially for the source rock from open or semi open gas producing strata.
Gas generation evaluation of Pingliang shale in Weibei Uplift, Ordos Basin using PetroMod
Authors: Shi Shuyong , Liao Lingling , He Zhihua , Wang Yunpeng 
Published: December 2020

Abstract
Ordos Basin is an important large petroliferous basin in China. In order to recover gas generation history and evaluate gas resources of Pingliang shale in Weibei Uplift, Ordos Basin, we took the Pingliang shale of Well XT-1 as the research target. We reconstructed burial and thermal histories of Pingliang shale based on PetroMod software. Besides, we also recovered gas generation history and its resources potential. The modeling results show that Well XT-1 had experienced five major tectonic stages. The burial depth of the bottom of Pingliang shale reached the maximum with the value of approximately 4500 m at the late Cretaceous and the current burial depth is 3068 m. The results of thermal history show that Pingliang shale had experienced oil-generation and gas-generation stages and current Ro is 2.52%. Based on the calculation results about gas generation history, generation masses of methane, wet gas, and total gas are 1.24 × 108 kg/km2, 0.88 × 108 kg/km2, 2.12 × 108 kg/km2, respectively, which shows great gas resource potential of Pingliang shale in Weibei uplift, Ordos Basin.
Sedimentary geochemical records and their depositional environmental significance during Cambrian-Ordovician transition in well YD 2, eastern Tarim Basin, NW China
Authors: Wang H Z , Zhang H Z , Deng Q , Wei Z W , Li S D , Cheng B , Liao Z W 
Published: December 2020

Abstract
In the eastern part of Tarim Basin, thick carbonate rocks were developed in the Upper Cambrian, while thick grey-black mudstone in the Lower Ordovician. Due to the complex tectonic and geological conditions in the basin, there are still many uncertainties in the study of the sedimentary environment, post-diagenesis and hydrocarbon accumulation conditions during the Cambrian-Ordovician transition. In this paper, 24 drilling core samples of the key strata of the Upper Cambrian-Lower Ordovician in the well YD2 were selected as the main research objects. Their mineral composition, major and trace elements (including REE) were analyzed. The results showed that the proportion of carbonate-siliciclastic sources in the rocks was controlled by the sedimentary environment, especially seawater depth. The oxic-suboxic sedimentary environment is indicated by the redox-sensitive elements and other trace elements (especially REE). This is consistent with the mineralogical features of the samples and the relatively low TOC. The elements Mn, Cr, V, Ni, on the whole, show a trend of first increasing, then decreasing, and repeated occurrence, indicating the sea level fluctuation cycle. In addition, according to the Ba/Sr and Mn/Sr ratios, the upper Cambrian carbonate rocks were normal marine sediments with weak post-diagenesis. Quartz, dolomite and calcite veins filling the fissures of the samples may have formed in the stage of intense uplift denudation, which was unfavourable to the formation of large oil and gas reservoirs.
Gas detecting of the Lower Permian dolomite reservoirs in Sichuan Basin using amplitude ratio attribute of PP-wave to PS-wave
Authors: Hongqiu Wang , Lu Zhou , Qiyan Chen , Kang Chen , Ronghua Wang , Xin Guo 
Published: December 2020

Abstract
At present, multi-wave multi-component seismic exploration has a good effect in the gas-bearing structural imaging improvement, fracture detection, clastic rock lithology description, reservoir monitoring, etc., but in gas detection, especially for the deep carbonate reservoir, there are not many successful cases. The paper takes the 5000m deep Lower Permian Qixia Formation dolomite gas reservoir in the central part of Sichuan Basin as the research target. Aiming at the differences in gas production characteristics of different wells and difficulty in gas detection, based on the high-precision matched 3D multi-wave seismic data by seismic processing and fine horizon interpretation of target formation, the differences between the PP- and PS-wave reflection amplitudes of high-production wells, low-production wells and poor gas wells are compared and analyzed, and multi-wave forward modelling and analysis are carried out. It is clear that the high production gas layer has the characteristics of strong PP-wave reflection and weaker PS-wave reflection. With the gas production decreasing from high to low, the reflection amplitude of PP gradually weakens, while that of PS change little and nearly have no obvious abnormalities. Finally, attribute of amplitude ratio of PP to PS were extracted for gas detection, which is in good agreement with the gas characteristics of the known wells and consistent with current geological understanding. The amplitude ratio attribute of PP to PS could provide a quick and reliable gas detection method for the deep dolomite reservoir.
Hydrocarbon generation from bacterial biomass in ca. 1320 million years ago
Authors: Wang Huajian , Zhang Shuichang , Wang Xiaomei , Zhang Baomin , Bian Lizeng , Bi Lina 
Published: December 2020

Abstract
Bacteria are the oldest life on the Earth. Some of them, such as cyanobacteria, can produce oxygen and organic matter through photosynthesis. However, the hydrocarbon generation ability of these bacterial biomass is still unclear. Here we reported the molecular evidence from the wrapped bitumen in well-preserved silicified concretions from the Xiamaling Formation, North China. The absence of steranes indicated negligible contribution of eukaryotic algae to the bitumen. Abundant hopanes, 13α(n-alkyl)-tricyclic terpanes and other biomarkers of bacteria prove that bacterial biogenic organic matter can generate hydrocarbons on a large scale. Combined with our previous microfossils and elements studies, these bitumen were considered to be from the Xiamaling shales, for the intrusion of Yanliao large igneous provinces into the organic-rich Xiamaling shales at ca. 1320 million years ago.
Geochemical characteristics and significance of the bitumen in Sinian reservoirs in Sichuan basin and its periphery
Authors: Xie Z Y , Li J , Zhang L , Yang C L , Guo J Y , Wang Z H , Li Z S , Guo Z Q , Zhang G W , Li J , Hao A S 
Published: December 2020

Abstract
The bitumen of Doushantuo Formation distributed along fractures has been firstly discovered in the dolomite reservoirs of Dou-3 Member in Zigui region, Yichang, Hubei. Research has been conducted using multiple methods on the characteristics of the newly discovered bitumen of Doushantuo Formation, bitumen of Dengying Formation-Longwangmiao Formation in Anyue gas field in Sichuan Basin, and bitumen of Sinian and source rocks of Sinian-Cambrian in Northeast Sichuan. The results show:①The reflectivity of the bitumen of Dou-3 Member is about 2.8%; ② The carbon number of n-alkanes in the bitumen of Dou-3 Member is C13-C33, where nC17 is the main peak; the relative proportion of the regular steranes is C27≈C29>C28, and C27, C28 and C29ααα20R steranes are distributed in “L” shape; abundant tricyclic terpanes and pentacyclic triterpanes have been detected, and the abundance of gammacerane is high; Aromatics are mainly phenanthrene series compounds. ③ The heteroatomic compounds in the bitumen of Dou-3 Member are mainly O2 carboxylic acids, and the oxygen compounds in the bitumen of Dengying Formation in Anyue gas field are close to those of the source rocks of Doushantuo Formation. The research results are of vital guiding significance to the study of potential source rocks of Doushantuo Formation in Sichuan Basin and the exploration of oil and gas from the source rocks of Doushantuo Formation.
Chemical characteristics of Middle Permian formation water and hydrocarbon preservation conditions in Northwest Sichuan
Authors: Yang C L , Xie Z Y , Pei S Q , Guo J Y , Zhang L , Dong C Y , Hao A S , Yang C X , Liu Z X 
Published: December 2020

Abstract
The analysis of the chemical characteristics of the Middle Permian formation water in 10 wells in the northwest of Sichuan Basin indicates that: the TDS of the Middle Permian formation water in Northwest Sichuan increases longitudinally with the burial depth of the formation, and the formation water is mainly of CaCl2 type (Surin classification), Cl-Na-Ca type and Cl-Ca-Na type (Shukarev classification). The rNa+/rCl− and rSO4
2-*100/rCl− of the formation water are 0.05-0.95 and 0-5 respectively, reflecting strong water-rock interaction and strong sealing conditions. The analysis of the chemical characteristics of formation water and the preservation conditions of oil and gas shows that the overall preservation conditions of the Middle Permian in Northwest Sichuan are good, most of which is located in the “preservation zone”; longitudinally, the preservation conditions of Qixia Formation are better than those of Maokou Formation; areally, the preservation conditions of Shuangyushi and Jiulongshan regions are good; the sealing property of the strata in Hewanchang region is poor.