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Modeling slow deformation of polygonal particles using DEM

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Particuology 2008年第6期6卷 506-514页

作者： Andrés A. Pea pedro G. lind Hans J. Herrmann Institute for Computational Physics Universitt Stuttgart Computational Physics IfB HIF E12 ETH Hnggerberg CH-8093 Zrich Switzerland Departamento de Física Universidade Federal do Ceará

We introduce two improvements in the numerical scheme to simulate collision and slow shearing of irregular particles. First, we propose an alternative approach based on simple relations to compute the frictional contact forces. The approach improves efficiency and accuracy of the Discrete Element Method （DEM） when modeling the dynamics of the granular packing. We determine the proper upper limit for the integration step in the standard numerical scheme using a wide range of material parameters. To this end, we study the kinetic energy decay in a stress controlled test between two particles. Second, we show that the usual way of defining the contact plane between two polygonal particles is, in general, not unique which leads to discontinuities in the direction of the contact plane while particles move. To solve this drawback, we introduce an accurate definition for the contact plane based on the shape of the overlap area between touching particles, which evolves continuously in time.

关键词： Granular media Discrete element method Slow deformation Contact forces

Transcatheter mitral valve repair in nonagenarians

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Journal of Geriatric Cardiology 2022年第1期19卷 90-94页

作者： pedro Luis Cepas-Guillén Isaac Pascual Eulogio Garcia Pilar Jimenez-Quevedo Alfonso Jurado-Roman Tomás Benito-González Rodrigo Estevez-Loureiro pedro li Dabit Arzamendi Bruno Meli.a Eduardo Infante de Oliveira pedro Martín Lorenzo Felipe Fernández-Vázquez Guillermo Galeote Luis Nombela-Franco Leire Unzue Pablo Avanzas Manel Sabate Xavier Freixa Cardiology Department Cardiovascular Institute(ICCV)Hospital ClinicIDIBAPSUniversity of BarcelonaBarcelonaSpain Interventional Cardiology Unit Hospital Universitario Central de AsturiasDepartment of MedicineUniversity of OviedoOviedoSpain Servicio de Hemodinámica y Cardiología Intervencionista HM CIEC-Centro Integral de Enfermedades CardiovascularesHospital Universitario HM MontepríncipeHM HospitalesMadridSpain Facultad de Medicina Universidad CEU San PabloMadridSpain Cardiology Department Cardiovascular InstituteHospital Clínico San CarlosIdISSCMadridSpain Division of Interventional Cardiology University Hospital La PazIdiPAZCIBER-CVMadridSpain Department of Cardiology University Hospital of LeónLeónSpain Interventional Cardiology Unit HospitalÁlvaro CunqueiroVigoSpain Interventional Cardiology Unit Hospital Sant Pau i Santa CreuBarcelonaSpain Serviço de Cardiologia Centro Hospitalar de Vila Nova de Gaia/Espinho-EPEVila Nova de GaiaPortugal Serviço de Cardiologia Hospital de Santa MariaCentro Hospitalar Lisboa NorteCentro Académico Médico de LisboaLisboaPortugal Servicio de Cardiología Hospital Universitario de Gran Canaria Dr.NegrínLas Palmas de Gran CanariaSpain

Given the increase in life expectancy indeveloped countries,nonagenarian population will become clinically and numerically relevant in our daily routine practice in the near *** has been observed to exert a profound influence on the prevalence of severe mitral regurgitation (MR) in the population.[1]Mitral valve surgery remains the gold standard of care for patients with symptomatic severe MR.

关键词： mitral routine surgery

Molecular signature of soil organic matter under different land uses in the Lake Chaohu Basin

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Eco-Environment & Health 2022年第4期1卷 212-218页

作者： Han Gao Huixin li Chen lin pedro J.J.Alvarez Caroline A.Masiello Dongqiang Zhu Ao Kong Xiaolei Qu State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023China School of Finance Nanjing University of Finance and EconomicsNanjing 210023China Key Laboratory of Watershed Geographic Sciences Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control Nanjing Institute of Environmental SciencesMinistry of Ecology and Environment of ChinaNanjing 210042China Department of Civil and Environmental Engineering Rice UniversityHouston TX 77005USA Department of Earth Environmental and Planetary SciencesRice UniversityHouston TX 77005USA School of Urban and Environmental Sciences Peking UniversityBeijing 100871China

The concentration and molecular composition of soil organic matter(SOM)are important factors in mitigation against cli.ate change as well as providing other ecosystem *** quantitative understanding of how land use influences SOM molecular composition and associated turnover dynamics is limited,which underscores the need for high-throughput analytical approaches and molecular marker signatures to clarify this *** a high-throughput untargeted mass spectrometry screening and molecular markers,we show that forest,farmland and urban land uses result in distinct molecular signatures of SOM in the Lake Chaohu *** markers indicate that forest SOM has abundant carbon contents from vegetation and condensed organic carbon,leading to high soil organic carbon(SOC)*** SOM has moderate carbon contents from vegetation,and limited content of condensed organic carbon,with SOC significantly lower than that of forest *** SOM has high abundance of condensed organic carbon markers due to anthropogenic activities but relatively low in markers from ***,urban soils have the highest black carbon/SOC ratio among these land ***,our results suggested that the molecular signature of SOM varies significantly with land use in the Lake Chaohu Basin,influencing carbon *** strategy of molecular fingerprinting and marker discovery is expected to enlighten further research on SOM molecular signatures and cycling dynamics.

关键词： High-throughput untargeted mass spectrometry screening Mass spectrum processing algorithm Soil organic matter Molecular signature Land use

Geochemical Analysis of Albian-Maastrichtian Formations in the Offshore Basin of the Abidjan Margin: Rock-Eval Pyrolysis Study

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Open Journal of Geology 2024年第8期14卷 805-822页

作者： N’Guessan Donald Ahoure Blandine Akissi Egoran Guy Richard N’Dri Kouadio Zokagon Sylvain Sehi Emmanuelle Laure Oura Zéli Bruno Digbehi UFR of Sciences and Technologies Alassane Ouattara Bouak Laboratory of Plant Biology and Earth Sciences Bouak Cte dIvoire UFR Marine Sciences San Pedro University San Pedro Cte dIvoire PETROCI Geochimistry Department at the Center for Analysis and Research Abidjan Cte dIvoire UFR/STRM Felix Houphout Boigny University of Abidjan Abidjan Cte dIvoire

The Albian-Maastrichtian interval of the Ivorian sedimentary basin has been the subject of numerous sedimentological, biostratigraphic, and geophysical studies. However, its geochemical characteristics remain relatively unexplored. This study aims to determine the oil potential and the nature of the organic matter it contains. It focuses on the geochemical analysis (physicochemical method) of two oil wells located in the offshore sedimentary basin of Côte d’Ivoire, specifically in the Abidjan margin. A total of 154 cuttings samples from wells TMH-1X and TMH-2X were analyzed to determine their oil potential and the nature of the organic matter (OM) they contain. The analyses were performed using Rock-Eval pyrolysis, a method that characterizes the amount of hydrocarbons generated by the organic matter present in the rocks. The key parameters measured include Total Organic Carbon (TOC), Hydrogen Index (HI), oil potential (S2), and maximum pyrolysis temperature (Tmax). These parameters are used to assess the amount of organic matter, its thermal maturity, and its potential to generate hydrocarbons in the studied wells. The results show significant variations between different stratigraphic levels. In well TMH-1X, the Cenomanian and Campanian intervals stand out with very good quantities of organic matter (OM) with good oil potential, although often immature. In contrast, other stages such as the Albian and Turonian contain organic matter in moderate to low quantities, often immature and of continental type, which limits their capacity to generate hydrocarbons. In well TMH-2X, a similar trend is observed. Despite an abundance of organic matter, the oil potential remains low in most of the studied stages. The organic matter is primarily of type III (continental origin) and thermally immature, indicating a low potential for hydrocarbon generation. The study reveals that, although some intervals exhibit high-quality organic matter, the majority of the samples show insuffic

关键词： Geochemistry Rock-Eval Pyrolysis Upper Senonian Petroleum Potential Côte d’Ivoire

Nutritional Composition of Ten Persimmon Cultivars in the “Ready-to-Eat Crisp” Stage. Effect of Deastringency Treatment

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Food and Nutrition Sciences 2015年第14期6卷 1296-1306页

作者： pedro Novillo Cristina Besada li Tian Almudena Bermejo Alejandra Salvador Postharvest Department Instituto Valenciano de Investigaciones Agrarias Moncada Valencia Spain Department of Plant Sciences University of California Davis CA USA

Traditionally persimmons have been consumed over-ripened to avoid astringency perception. However, the introduction of new technology that removes astringency while preserving fruit firmness has allowed the commerciali.ation of “ready-to-eat crisp” fruits. Several studies have evaluated the nutritional composition of over-ripened persimmons and have claimed that they are a good source of primary and secondary metabolites that are favourable for human health. Yet very little is known about the nutritional composition of persimmons in the “ready-to-eat crisp” stage. In this context, we determined the main nutritional compounds in ten popular persimmon cultivars, including astringent cultivars (“Rojo Brillante”, “Tone Wase”, “Giboshi”, “Kaki Tipo”, “Aizumishirazu-A”, “Giombo”, “Hachiya”) and non-astringent cultivars (“O’gosho”, “Hana Fuyu” and “Jiro”). To this end, fruits were harvested when their texture was firm, and soluble polyphenols content, total antioxidant capacity and main sugars, organic acids and carotenoids were evaluated. In those astringent cultivars at harvest, the changes in nutritional compounds associated with applying deastringency treatment with high CO2 concentration were determined. Our results revealed the main sugars (glucose, fructose and sucrose), organic acids (citric acid, malic acid and succinic) and carotenoids (β-cryptoxanthin, lutein, violoxanthin, zeaxanthin, and β-carotene) present in the flesh of crisp persimmons. At harvest the content of these metabolites vastly varied among cultivars;astringent cultivars showed higher soluble polyphenols and greater antioxidant capacity, and presented higher contents of sugars and organic acids than non-astringent ones. The deastringency treatment applied to astringent cultivars resulted in a drastic loss of soluble polyphenols and total antioxidant capacity, and induced changes in carotenoids and sugars composition.

关键词： Persimmon Crispy Texture Nutritional Composition Antioxidant Capacity Deastringency Treatment

Aerodynamic effects on a railway tunnel with partially changed cross-sectional area

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Journal of Central South University 2022年第8期29卷 2589-2604页

作者： li Wen-hui liU Tang-hong MARTINEZ-VAZQUEZ pedro XIA Yu-tao CHEN Zheng-wei GUO Zi-jian Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic&Transportation EngineeringCentral South UniversityChangsha 410075China Joint International Research Laboratory of Key Technology for Rail Traffic Safety Central South UniversityChangsha 410075China National&Local Joint Engineering Research Centre of Safety Technology for Rail Vehicle Central South UniversityChangsha 410075China School of Engineering The University of BirminghamEdgbastonB152TTUnited Kingdom Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

The present study numerically explored the aerodynamic performance of a novel railway tunnel with a partially reduced *** impact of the reduction rate of the tunnel cross-section on wave transmissions was analyzed based on the three-dimensional,unsteady,compressible,and RNG k-εturbulence *** results highlight that the reduction rate(S)most affects pressure configurations at the middle tunnel segment,followed by the enlarged segments near access,and finally the *** strength of the newly generated compression wave at the tunnel junction where the cross-section abruptly changes increases exponentially with the decrease of the cross-sectional *** maximum peak-to-peak pressureΔP on the tunnel and train surface for non-uniform tunnels is reduced by 10.7%and 13.8%,respectively,compared with those of equivalent uniform ***,the economic analysis suggests that the aerodynamic performance of the developed tunnel prototype surpasses those conventional tunnels based on the same excavated volume.

关键词： high-speed train railway tunnel cross-section transient pressure blockage ratio

Sex-specific differences in white matter microvascular integrity after ischaemic stroke

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Stroke & Vascular Neurology 2019年第4期4卷 198-205页

作者： Mark R Etherton Ona Wu pedro Cougo Svetlana Lorenzano Hua li li.a Cloonan Mark J R J Bouts Arne Lauer Ken Arai Eng H Lo Steve K Feske Karen L Furie Natalia S Rost Department of Neurology Massachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA Martinos Center for Biomedical Imaging Massachusetts General HospitalCharlestownMAUnited States Department of Radiology Massachusetts General Hospital and Harvard Medical SchoolBostonMAUnited States Medical School of Ribeirao Preto University of Sao PauloSao PauloBrazil Department of Human Neurosciences Sapienza University of RomeRomeItaly Institute of Psychology Leiden UniversityLeidenNetherlands Department of Neuroradiology Goethe-Universitat Frankfurt am MainFrankfurtGermany Department of Neurology Brigham and Women’s Hospital and Harvard Medical SchoolBostonMAUnited States Department of Neurology Warren Alpert Medical School of Brown UniversityProvidenceRhode IslandUSA

background and purpose Functional outcomes after ischaemic stroke are worse in women,despite adjusting for differences in comorbidities and treatment *** matter microvascular integrity represents one risk factor for poor long-term functional outcomes after ischaemic *** aim of the study is to characterise sex-specific differences in microvascular integrity in individuals with acute ischaemic *** A retrospective analysis of subjects with acute ischaemic stroke and brain MRI with diffusion-weighted(DWI)and dynamic-susceptibility contrast-enhanced(DSC)perfusion-weighted imaging obtained within 9 hours of last known well was *** the hemisphere contralateral to the acute infarct,normal-appearing white matter(NAWM)microvascular integrity was measured using the K_(2) coefficient and apparent diffusion coefficient(ADC)*** analyses for predictors of K_(2) coefficient,DWI volume and good outcome(90-day modified Rankin scale(mRS)score<2)were *** 105 men and 79 women met inclusion criteria for *** no difference in age,women had increased NAWM K_(2) coefficient(1027.4 vs 692.7×10^(-6)/s;p=0.006).In women,atrial fibrillation(β=583.6;p=0.04)and increasing NAWM ADC(β=4.4;p=0.02)were associated with increased NAWM K_(2) *** multivariable regression analysis,the K_(2) coefficient was an independent predictor of DWI volume in women(β=0.007;p=0.01)but not *** In women with acute ischaemic stroke,increased NAWM K_(2) coefficient is associated with increased infarct volume and chronic white matter structural *** studies investigating sex-specific differences in white matter microvascular integrity are needed.

关键词： microvascular white coefficient

Influence of the operating temperature on the ageing and interfaces of double layer polymer electrolyte solid state li metal batteries

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Nano Research 2023年第6期16卷 8377-8384页

作者： Mikel Arrese-Igor María Martinez-Ibañez Ander Orue Ekaterina Pavlenko Erwan Dumont Michel Armand Frédéric Aguesse pedro López Aranguren Centre for Cooperative Research on Alternative Energies(CIC energiGUNE) Basque Research and Technology Alliance(BRTA)Alava Technology ParkAlbert Einstein 48Vitoria-Gasteiz 01510Spain University of the Basque Country(UPV/EHU) Barrio Sarrienas/nLeioa 48940Spain Saft 111 Boulevard Alfred DaneyBordeaux Cedex 33074France

Solid-state lithium metal batteries(SSLMBs)are considered an auspicious technology to develop high energy density and safe energy storage *** double layer polymer electrolyte(DLPE)is a rational approach for engineering high-performance SSLMBs addressing electrolyte requirements with specifically designed polymers at the positive electrode and as *** this work,SSLMBs were assembled with poly(propylene carbonate)(PPC),offering stability toward oxidation at the positive electrode,and a gel polymer electrolyte with polyethyleneglycol dimethylether(PEGDME)as separator,offering high ionic conductivity at low temperature and sufficient interfacial stability with li *** electrochemical properties and performance of cells with liFePO_(4) and li[Ni_(0.6)Mn_(0.2)Co_(0.2)]O_(2) positive electrodes are thoroughly investigated as function of the operating temperature by using a host of characterization ***-voltage cells with an areal capacity of 0.7 mAh·cm^(−2)cycled at 40℃ exhibit a higher capacity retention than the cells cycled at 70℃.To understand such differences,a three-electrode setup is applied to discriminate anodic processes from cathodic as function of the *** elucidate the ageing and interfacial evolution for DLPE cells with gel polymer electrolytes paving the way for building performance solid state batteries.

关键词： double layer polymer electrolyte solid-state lithium metal battery gel polymer electrolyte high voltage interfacial study

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纳米铁为脱氯菌供电降解三氯乙烯实验研究

环境科学 2009年第6期30卷 1791-1796页

作者：修宗明李铁龙金朝晖 pedro J. Alvarez 南开大学环境科学与工程学院天津300071 南开大学环境污染过程与基准教育部重点实验室天津300071 Department of Civil and Environmental Engineering Rice University

采用一种从氯乙烯污染场址土壤中提取的脱氯菌种(Dehalococcoidesspp.)进行三氯乙烯(TCE)降解实验,研究纳米铁厌氧腐蚀产氢为该脱氯菌种提供电子的可能性.结果表明,在甲醇做电子供体时,稀释25倍的菌液[(2.0±0.44)×105cell/mL)]可以在9... 详细信息

采用一种从氯乙烯污染场址土壤中提取的脱氯菌种(Dehalococcoidesspp.)进行三氯乙烯(TCE)降解实验,研究纳米铁厌氧腐蚀产氢为该脱氯菌种提供电子的可能性.结果表明,在甲醇做电子供体时,稀释25倍的菌液[(2.0±0.44)×105cell/mL)]可以在96 h内将20 mg/L TCE完全降解,并在190 h时有2.706μmol乙烯产生.而在无甲醇做电子供体时,96 h内只有部分TCE转化为顺二氯乙烯(cis-DCE),且190 h时几乎无乙烯产生(0.159μmol),因此无电子供体时菌液脱氯活动不能维持.但在4 g/L纳米铁腐蚀产氢的情况下,脱氯菌可以利用纳米铁产生的阴极氢维持脱氯活动,在131 h内将20 mg/L TCE完全降解,并且其耦合的脱氯速率高于纳米铁单独降解时的速率.从乙烯的产量分析中可以看出,纳米铁供电时190 h后由脱氯菌产生的乙烯量为1.187μmol,明显低于甲醇做电子供体时乙烯的产量2.706μmol,表明纳米铁可能对微生物存在一定的毒性效应.同时反应190 h后乙炔的产量为0.109μmol,相对低于与纳米铁单独降解TCE时的产量0.161μmol,说明微生物在无电子供体的情况下,竞争利用了纳米铁与水反应产生的电子导致乙炔的生成量降低.上述结果表明,4 g/L的纳米铁与水反应生成的活性氢可以为脱氯菌提供电子,并维持其脱氯活动,这对纳米铁和脱氯菌耦合应用于地下水的有机氯修复具有重要的实际意义.

关键词：纳米铁脱氯菌 TCE 电子供体