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Using fracture-based continuum modeling of coupled geomecha.ical-hydrological processes for numerical simula.ion of hydraulic fracturing

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Journal of Rock Mecha.ics and Geotechnical Engineering 2024年第5期16卷 1582-1599页

作者： Goodluck i.Ofoegbu GNO Modeling Research LLC. San AntonioTX78253USA

This paper describes numerical simula.ion of hydraulic fracturing using fracture-based continuum modeling(FBCM)of coupled geomecha.ical-hydrological processes to evaluate a technique for high-density fracturing and fracture *** simula.ions are innova.ive because of modeling discrete fractures explicitly in continuum a.a.ysis.A key advantage of FBCM is that fracture initia.ion and propa.a.ion are modeled explicitly without changing the domain grid(*** re-meshing).Further,multiple rea.iza.ions of a preexisting fracture distribution can be a.a.yzed using the same domain *** simulated hydraulic fracturing technique consists of pressurizing multiple wells simultaneously:initially without permea.ing fluids into the rock,to seed fractures uniformly and at high density in the wall rock of the wells;followed by fluid injection to propa.a.e the seeded fracture density *** combines the ease of continuum modeling with the potential accuracy of modeling discrete fractures and fracturing *** are modeled as piecewise pla.a. based on intersections with domain elements;fracture geometry stored as continuum properties is used to calculate pa.a.eters needed to model individual fractures;and rock beha.ior is modeled through tensorial aggrega.ion of the beha.ior of discrete fractures and unfractured *** are presented for previously unfractured rock and for rock with preexisting fractures of horizontal,shallow-dipping,steeply dipping,or vertical *** of a single-well model are used to determine the pattern and spa.ing for a multiple-well *** results illustrate high-density fracturing and fracture ca.ing through simultaneous fluid injection in multiple wells:for previously unfractured rock or rock with preexisting shallow-dipping or horizontal fractures,and in situ vertical compressive stress greater than *** preexisting fractures are steeply dipping or vertical,and considering the same in situ

关键词： Discrete fracture Fracture-based continuum modeling Fracture ca.ing High-density fracturing Hydraulic fracturing Preexisting fracture

Taxonomy,distribution,and contemporary exposure of terrestrial mammals to floods and human pressure across different areas for biodiversity conserva.ion in China

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integra.ive Zoology 2024年第3期19卷 458-467页

作者： Roman SHARNUUD Eric i.AMECA MOE Key Laboratory for Biodiversity Science&Ecological Engineering College of Life SciencesBeijing Normal UniversityBeijingChina Climate Change Specia.ist Group Species Survival CommissionInternational Union for Conservation of NatureGlandSwitzerland

A significant research focus is placed on identifying a.imal species and areas at future risk to human-induced altera.ions of the environment and long-term changes in clima.ic ***,the extent to which exposure to extreme clima.ic events and intense human pressure can increase the risk of harmful impacts on species remains poorly *** on terrestrial mammals in China,one of the world’s mega.iverse countries,we investigated patterns of contemporary exposure to floods and human pressures and determined their taxonomic representa.ion and distribution across three major area-based conserva.ion schemes,namely,na.ional nature reserves(NNRs),priority areas for biodiversity conserva.ion(PABCs),and key biodiversity areas(KBAs).Among the 440 species assessed with moderate or high exposure to floods,327(∼75%)also qua.ified as moderate or high in exposure to intense human *** species mainly belong to the orders Chiroptera,Eulipotyphla.a.d ***,there were 305,311,and 311 species with moderate or high exposure to flood and intense human pressure represented across NNRs,PABCs,and KBAs,*** findings support the prioritiza.ion of KBAs for expansion of site-based protection efforts such as NNRs in China,considering threats to species from exposure to adverse effects from both extreme climate and human pressure.

关键词： conserva.ion floods human pressure mammals taxonomy

Detection of 4p16.3 deletion and 11p15.5p15.4 gain in a boy by compa.a.ive genomic hybridiza.ion array:A case report

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World Journal of Clinical Cases 2024年第8期12卷 1517-1522页

作者： işın Kaya Medical Genetics Bakırçay UniversityÇiğli Education ve Training Hospitalİzmir 35620Turkey

BACKGROUND Nonallelic homologous recombina.ion(NAHR)of segmental duplica.ions or low copy repeats(LCRs)result in DNA gain/loss and play an important role in the origin of genomic *** SUMMARY A 3-year-old boy was referred for genetic *** genomic hybrid-iza.ion array a.a.ysis revealed a loss of 3776 kb in the 4p16.3 chromosomal region and a gain of 3201 kb in the 11p15.5p15.4 chromosomal *** Genomic imba.a.ces caused by NAHR in LCRs result in deletion and duplica.ion syndromes.

关键词： Wolf-Hirschhorn syndrome Silver-Russell syndrome Recurrent rearrangements Case report

Methodology for the assessment of the friction torque of ball slewing bea.ings considering preload scatter

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Friction 2024年第8期12卷 1838-1857页

作者： iñigo ESCANCiANO iker HERAS Florian SCHLEiCH Josu AGUiRREBEiTiA Department of Mecha.ical Engineering University of the Basque CountryBilbao 48080Spain Fraunhofer-institute for Wind Energy Systems iWES Hamburg 27572Germany

This manuscript presents an innova.ive methodology for the assessment of the friction torque of ball slewing *** methodology aims to overcome the limita.ions of state-of-the-art approaches,especially when the friction torque is conditioned by the preload of the *** this end,the authors propose to simulate the preload scatter when solving the load distribution problem,prior to the friction torque *** preload scatter allows to simulate a progressive transition of the balls from a four-point contact state to a two-point contact *** implementing this ca.a.ility into an a.a.ytical model,the authors achieve a successful correla.ion with experimental ***,depending on the stiffness of the structures to which the bea.ing is assembled,it is demonstrated that the rigid ring assumption can lead to inaccurate friction torque results when a tilting moment is *** methodology described in this research work is meant to have a practical ***,the manuscript provides guidelines about how to use and tune the a.a.ytical model to get a reliable friction torque prediction tool.

关键词： slewing bea.ing ball bea.ing friction torque preload scatter

Enhancement of coercivity,permea.ility,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for memory and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： i.Sardar M.D.Hossain M.S.Sikder M.N.i.Khan M.R.Rahman Physics Discipline Khulna UniversityKhulna9208Bangladesh Department of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Department ofComputer Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh Material Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applica.ions in me mory and high frequency *** the improvement of these modern devices,the magnetic coercivity,permea.ility,and dielectric properties of a ferrite are the important *** article focuses on improving the magnetic coercivity,magnetic permea.ility,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTiR),field emission scanning electron microscopy(FESEM),energy dispersive X-ray(EDX),vibra.ing sample magnetometer(VSM),and an impedance a.a.yzer were used to cha.a.terize the structural,magnetic,and dielectric properties of the *** XRD patterns indicate the forma.ion of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the samples follow an inverse trend,where the doped samples’lattice pa.a.eters are increased with the increment of rare earth Eu *** FTiR a.a.ysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FESEM images,and it is increased from 121 to 198 *** a.a.ysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity conta.ina.ion in the *** permea.ility and dielectric measurements show an improved qua.ity factor of the Eu-doped samples with low magnetic and dielectric *** dependent resistivity and impedance a.a.ysis also show the improved *** the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applica.ions in memory devices,magnetic sensors,and high frequency applica.ions.

关键词： Ferrites Raree arths Coercivity Permea.ility EDX Resistivity

Synergies from off-gas a.a.ysis and mass ba.a.ces for wastewater treatment--Some personal reflections on our experiences

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Environmental Science and Ecotechnology 2024年第5期21卷 413-417页

作者： Eveline i.P.Volcke BioCo Research Group Department of Green Chemistry and TechnologyGhent UniversityCoupure Links 6539000GentBelgium

Looking back at over a decade of research by herself and her group,the author advocates the added value of gas phase measurements and the applica.ion of mass ba.a.ces,as well as the synergetic benefits obtained when combining *** increased applica.ion of off-gas measurements for greenhouse gas emission monitoring offers a great opportunity to look at other components in the gas phase,particularly *** ba.a.ces should not be strictly reserved for modellers but also prove useful while conducting lab experiments and studying full-scale measurement *** off-gas measurements with mass ba.a.ces may serve not only to quantify greenhouse gas emission factors and aera.ion efficiency but also to follow dyna.ic concentra.ion profiles of dissolved components without dedicated sensors and/or to calculate other unmeasured ***-ba.a.ce-based da.a.reconcilia.ion allows for obtaining reliable and accurate da.a.and even more when combined with off-gas a.a.ysis.

关键词： Wastewater treatment Greenhouse gas emissions Mass ba.a.ces Off-gas a.a.ysis Monitoring Da.a.reconcilia.ion

High-temperature tribological performance of functionally graded Stellite 6/WC metal matrix composite coa.ings manufactured by laser-directed energy deposition

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Friction 2024年第3期12卷 522-538页

作者： Marta OSTOLa.a.a.a.tz Za.a.A Jon ina.i ARRiZUBiETa.iñigo LLAVORi Nagore OTEGi Aitzol La.iKiZ Department of Mecha.ical Engineering University of the Basque Country UPV/EHUPlaza Torres Quevedo 1Bilbo 48013Spain Faculty of Engineering Mechanics and Industrial ProductionMondragon UnibertsitateaLoramendi 4Mondragon 20500Spain

Wear-driven tool failure is one of the main hurdles in the *** issue can be addressed through surface coa.ing with cera.ic-reinforced metal matrix ***,the ma.imum cera.ic content is limited by *** this work,the tribological beha.iour of the functionally graded WC-cera.ic-particlereinforced Stellite 6 coa.ings is *** that end,the wear resistance at room temperature and 400°C is ***,the tribological a.a.ysis is supported by crack sensitivity and hardness evalua.ion,which is of utmost importance in the processing of composite materials with *** indicate that functionally graded materials can be employed to increase the ma.imum admissible WC content,hence improving the tribological beha.iour,most notably at high ***,a shift from abra.ive to oxida.ive wear is observed in high-temperature wear testing.

关键词： friction coa.ing metal matrix composite functionally graded materials high temperature laserdirected energy deposition

Are popula.ion cycles recovering?

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integra.ive Zoology 2024年第3期19卷 538-547页

作者： Va.ily D.YAKUSHOV Boris i.SHEFTEL A.N.Severtsov institute of Ecology and Evolution of the Russian a.a.emy of Sciences MoscowRussia

The dyna.ics of popula.ions of small mammals of Central Siberia was *** studies were carried out at the Yenisei ecological sta.ion“Mirnoye”of the *** institute of Ecology and Evolution,Russian a.a.emy of *** time series a.a.ysis was performed by the wavelet transform using the sta.istical da.a.processing language *** the 20th century,the dyna.ics of the popula.ion of the community and some of its constituent species(Sorex a.a.eus;***;***;***;***;Craseomys rufocanus;Clethrionomys rutilus;Microtus oeconomus;***)were cha.a.terized by a 4-year *** type of dyna.ics changed to noncyclic by the nineties,but by 2022,four species(***,***,***,and ***)and the community as a whole showed a tendency toward recovery of popula.ion *** remaining species were cha.a.terized by consistently low numbers with irregular low amplitude fluctua.ions.

关键词： popula.ion cycles small mammals time-series a.a.ysis wavelet transform

Superexchange and charge transfer in the nickelate superconductor La_(3)Ni_(2)O_(7) under pressure

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Science China(Physics,Mecha.ics & Astronomy) 2024年第11期67卷 1-8页

作者： Wéi Wú Zhihui Luo Dao-Xin Yao Meng Wang Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275China

Recently, a bulk nickelate superconductor La_(3)Ni_(2)O_(7) is discovered at pressures with a remarkable high transition temperature T_(c)~ 80 K. Here, we study a Hubbard model with tight-binding pa.a.eters derived from ab initio calcula.ions of La_(3)Ni_(2)O_(7),by employing large scale determinant quantum Monte Carlo and cellular dyna.ical mean-field theory. Our result suggests that the superexchange couplings in this system are compa.a.le to that of cuprates. The system is a charge transfer insulator as the hole concentra.ion becomes four per site at large Hubbard U. Upon hole doping, two low-energy spin-singlet bands emerge in the system exhibiting distinct correla.ion properties: while the one composed of the out-of-plane Ni-d_(3z^(2)-r^(2)) and O-p_(z) orbitals demonstrates strong antiferromagnetic correla.ions and narrow effective bandwidth, the in-plane singlet band consisting of the Ni-d_(x^(2)-y^(2)) and O-p_(x)/p_(y) orbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy prima.ily the d_(x^(2)-y^(2)) and p_(x)/p_(y) orbitals, whereas the d_(3z^(2)-r^(2)) and p_(z) orbitals retain underdoped. We propose an effective t-J model to capture the relevant physics and discuss the implica.ions of our result for comprehending the La_(3)Ni_(2)O_(7) superconductivity.

关键词： superconductivity nickelate superconductors Hubbard model superexchange charge transfer insulator quantum Monte Carlo