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Numerical Study of Flow Features Around Submerged Circular and Square Piles at Flat and Scoured Beds Using OpenFOAM

Journal of Ocean University of China 2024年第4期23卷 897-914页

作者： WANG Chaolin WU Guoxiang WANG Dianhe DU Shengtao ZHANG Zhiyong JIN Heng ZHU david Z. LIANG Bingchen Donghai Academy School of Civil&Environmental Engineering and Geography ScienceNingbo UniversityNingbo 315211China Key Laboratory of Estuary and Coast of Zhejiang Province and Zhejiang Institute of Hydraulics and EstuaryHangzhou 310020China Shandong Provincial Key Laboratory of Ocean Engineering and College of EngineeringOcean University of ChinaQingdao 266100China Shandong Water Conservancy Vocational College Rizhao 276826China School of Mechanical and Energy Engineering Ningbotech UniversityNingbo 315211China

Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth *** study details the flow turbulence characteristics of two submerged piles that are determined by solving the Navier-Stokes equations with the improved delayed detached eddy simulation *** model is verified by comparing experimental and numerical results for hydrodynamic parameters with the literature for both square-crossing piles(SCPs)and circular-crossing piles(CCPs).Original topographies of flat and scoured beds(i.e.,the initial and equilibrium scouring stages)are based on experimental results obtained by the authors in the present *** and CCP flow features in the scouring process are *** results indicate that during the scouring process,the time-averaged drag coefficient and root mean square(rms)of the lift coefficient increase linearly in the CCP test,while the rms of the lift coefficient in the SCP test decreases ***,the minimum pressure coefficient is always located in the upstream corners in the SCP case but moves from 72.5°to 79.5°when the scour hole is completely developed in the CCP *** flow behind the pile,which is generated by separated boundary layers above the top face of the pile,can reach the sand bed and turn the separated shear layers into patches of small vortices in the near-wake ***,the high shear stress zones are mainly at the scour edges under scoured-bed conditions.

关键词： flat bed scoured bed local scour OpenFOAM bed shear stress

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Making bridges between preclinical and clinical insights into age-related cognitive decline

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Neural Regeneration Research 2025年第8期20卷 2321-2322页

作者： david VC Brito Clévio Nóbrega Algarve Biomedical Center-Research Institute(ABC-RI) Campus GambelasFaroPortugal Algarve Biomedical Center-(ABC) Campus GambelasFaroPortugal Faculty of Medicine and Biomedical Sciences(FMCB) University of AlgarveGambelas CampusFaroPortugal

With people living longer,the societal impact of age-related cognitive decline is becoming more pronounced(Crimmins,2015).Thus,it is increasingly important to comprehend the cognitive shifts linked to aging-whether th... 详细信息

关键词： bridges becoming insight

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Cardiovascular risk burden and disability:findings from the International Mobility in Aging Study(IMIAS)

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Journal of Geriatric Cardiology 2024年第3期21卷 331-339页

作者： Juan-david Martinez-Aristizábal Carmen-Lucia Curcio Juliana Fernandes Afshin Vafael Cristiano dos Santos Gomes Fernando Gomez Internal Medicine Critical Care DepartmentPablo Tobón Uribe HospitalMedellínColombia Research Group in Geriatrics and Gerontology Faculty of Health SciencesUniversidad de CaldasManizalesColombia Laboratory of Physical Therapy and Collective Health Physical Therapy DepartmentFederal University of PernambucoJornalista Aníbal Fernandes Avenue RecifeBrazil Department of Public Health Sciences Queen’s UniversityKingstonONCanada Department of Physiotherapy University of PernambucoBR 203KmBrazil

BACKGROUND The association of cardiovascular risk burden with disability is *** examined the association between trajectories of the Framingham general cardiovascular disease risk score(FGCRS)with the trajectories of limitations of physical function in older *** A total of 1219 participants with no disabilities from the International Mobility in Aging Study(IMIAS)study who had up to three repeated measures of FGCRS between 2012–2016 and without a history of stroke or coronary heart disease at baseline and follow-up were *** at baseline was assessed and categorized into *** function was evaluated with the Short Physical Performance Battery(SPPB).The data were analyzed using linear mixed-effects *** At baseline,FGCRS ranged between 3–94(mean score:24±15.8),participants were 32(2.6%),502(41.2%)and 685(56.2%)in lowest,middle,and highest tertiles,*** the trajectories of limitations of physical function,the lowest FGCRS had no differences,while the middle and highest had a decrease in physical performance between 2012–2014(P=0.0001).Age,being female,living in Andes Mountains,having middle and highest FGCRS,higher alcohol consumption,being obese,lack of exercise and cognitive impairment increase the probability of disability(P<0.05).Alternatively,living in more developed regions and having a higher educational level reduced the probability of disability during the follow-up time(P<0.05).CONCLUSIONS Higher cardiovascular risk burden is associated with decreased physical performance,especially in *** suggest SPPB may provide a measure of cardiovascular health in older adults.

关键词： finding Battery burden

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Past, Present and Future: A Role for Liquid Biofuels in Transitioning to Net Zero?

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Natural Resources 2024年第5期15卷 107-124页

作者： david Michael Mousdale Beò carta Ltd. Glasgow United Kingdom

Over the last decade, the uptake rate of first-generation biofuels (ethanol and biodiesel) has decelerated as low blend limits have increased only slowly and extreme volatility in oil prices has limited investment in biofuels production infrastructure. Concerns over the environmental impacts of large-scale biofuels production combined with tariff barriers have greatly restricted the global trade in biofuels. First-generation biofuels produced either by fermentation of sugars from maize or sugarcane (ethanol) or transesterification of triglycerides (biodiesel) presently contribute less than 4% of terrestrial transportation fuel demand and techno-economic modelling foresees this only slowly increasing by 2035. With internal combustion and diesel engines widely anticipated as being phased out in favour of electric power for motor vehicles, a much-reduced market demand for biofuels is likely if global demand for all liquid fuels declines by 2050. However, second-generation, thermochemically produced and biomass-derived fuels (renewable diesel, marine oils and sustainable aviation fuel) have much higher blend limits;combined with policies to decarbonise the aviation and marine industries, major new markets for these products in terrestrial, marine and aviation sectors may emerge in the second half of the 21st century.

关键词： Biofuels Ethanol Biodiesel Renewable Diesel Sustainable Aviation Fuel Biomass

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Sex Determination in Homo sapiens as a Multi-Step Process: Potential for Development of Variants and Sex Differences in Disease Risk

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Journal of Biomedical Science and Engineering 2024年第1期17卷 13-34页

作者： david A. Hart Department of Surgery Faculty of Kinesiology McCaig Institute for Bone & Joint Health University of Calgary Cal-gary Canada

Reproduction via cis-binary mechanisms appears to have evolved fairly early in the evolution of complex organisms, and a system committed to prior to evolution of humans. While the evolution of a chromosomal-specific approach has been a successful strategy for survival of a large variety of species including humans, the fidelity of sex determination leading to 100% cis-binary outcomes is not achieved in many species, with evidence for homosexual or bisexual behaviour evident in more than 1500 species. Thus, such outcomes indicates that sex determination is a multi-step process and not a single event, and as such, could lead to the appearance of variants during the process which developed much earlier than humans. Variants could arise either due to intrinsic variation in the steps of determination, or also be influenced by environmental factors of a biological or psychological nature. In contrast to homosexual variants which do not require interventions such as hormone therapy or surgery, expression of gender dysphoria, is more based in psychology, but also has biological underpinnings and can be influenced by such hormonal interventions and surgery. While the numbers of those with gender dysphoria is small (~0.6% - 1.0% of population), the attention given to this issue raises the possibility of biological and psychological environmental factors impacting the emergence of some of those expressing gender dysphoria. Furthermore, transitioning from male-to-female or female-to-male can have consequences regarding disease risks latter in life, including the appearance of autoimmune diseases. This review will attempt to review some of the evidence regarding sex determination, discuss why the system has potentially not been improved upon during evolution, how a potential role for sex chromosome function on neurodevelopment may be central to variation in humans, and how commitment to the current strategy is likely integrated into other sex-related events such as puberty, pre

关键词： Sex Determination Variant Development Fidelity of Sex Determination Biological Sex Determination Species Variation

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Post-layout simulation driven analog circuit sizing

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Science China(Information Sciences) 2024年第4期67卷 289-300页

作者： Xiaohan GAO Haoyi ZHANG Siyuan YE Mingjie LIU david Z.PAN Linxiao SHEN Runsheng WANG Yibo LIN Ru HUANG School of Integrated Circuits Peking University School of Computer Science Peking University Department of Electrical and Computer Engineering University of Texas at Austin Institute of Electronic Design Automation Peking University

Post-layout simulation provides accurate guidance for analog circuit design, but post-layout performance is hard to be directly optimized at early design stages. Prior work on analog circuit sizing often utilizes pre-layout simulation results as the optimization objective. In this work, we propose a post-layoutsimulation-driven(post-simulation-driven for short) analog circuit sizing framework that directly optimizes the post-layout simulation performance. The framework integrates automated layout generation into the optimization loop of transistor sizing and leverages a coupled Bayesian optimization algorithm to search for the best post-simulation performance. Experimental results demonstrate that our framework can achieve over 20% better post-layout performance in competitive time than manual design and the method that only considers pre-layout optimization.

关键词： analog EDA transistor sizing Bayesian optimization post-layout simulation

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Failure mechanism and simulation for long run-out of the catastrophic rock landslide in the Shanyang Vanadium Mine,China

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Journal of Mountain Science 2024年第9期21卷 2905-2917页

作者： LIU Yinpeng Mumtaz HAIDER david-darnor LAWRENCE LI Tonglu SHEN Wei LI Ping College of Geological Engineering and Geomatics Chang’an UniversityXi’an 710054China Observation and Research Station of Water Cycle and Geological Environment for the Chinese Loess Plateau Ministry of EducationZhengning 745399China

On 12th August 2015,a massive rapid long run-out rock landslide occurred in the Shanyang Vanadium Mine in Shaanxi Province,China,which claimed the lives of 65 *** heavy rainfalls,earthquakes,and mining blasts were recorded before the ***,the failure mechanism and the cause of the long run-out movement are always in *** this paper,we conducted a detailed field investigation,laboratory tests,block theory analysis,and numerical simulation to investigate the failure and long run-out mechanisms of the *** field investigation results show that the source material of the rock landslide is a huge dolomite wedge block bedding on siliceous shale *** compression tests indicate that the uniaxial compression strength of the intact dolomite is 130-140MPa and the dolomite shows a brittle failure *** to the progressive downward erosion of the gully,the dolomite rock bridge at the slope toe became *** the compression stress in the dolomite bridge increased to surpass its strength,the brittle failure of the bridge *** huge potential energy was released following the disintegration of the landslide,which led to the high acceleration of this rock *** 3D discrete element simulation results suggest that the low intergranular friction contributes to the long run-out movement of this rock landslide.

关键词： Rock landslide Gully erosion Long run-out Wedge block Discrete element method

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The Impact of the Inclusion of MgO Nano-Fillers in a Polyethylene Matrix on Dielectric Strength and Resistance to Partial Discharges

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Open Journal of Applied Sciences 2024年第3期14卷 626-634页

作者： Virginie Griseri Dominique Mary david Malec Eric david Laboratoire Plasma et Conversion d’énergie Université de Toulouse CNRS UPS INPT Route de Narbonne Toulouse France É cole de Technologie Supérieure de Montréal Rue Notre-Dame Ouest Montréal Canada

One commonly used strategy to enhance polymers specific properties such as the resistance to partial discharges erosion is the incorporation into the polymeric matrix of inorganic micro or nanoparticles. This study focused on the dielectric properties of Low-Density Polyethylene (LDPE) filled with nano-sized Magnesium Oxide (MgO) particles compounded by thermo-mechanical process and one of the purposes was to establish appropriate processing parameters in order to reach the desired dielectric properties. LDPE was used as a matrix and was reinforced by MgO particles having a nominal average size of 30 nm. The MgO nanoparticles were treated with a silane coupling agent (3-Glycidyloxypropyl Trimethoxysilane). The samples were initially prepared in a melt-mixing chamber with a MgO content of 1% wt. These pre-mixed samples were further treated by the means of thermo-mechanical mixing in a conical co-rotating twin-screw extruder in order to improve the dispersion and distribution of the MgO particles. In this report, both lifetime under a PD activity and AC dielectric strength of pure and nano-filled LDPE samples have been measured and compared. Nano-filled LDPE samples were found to exhibit an improve lifetime, without any detrimental impact on their short-term dielectric strength. This suggests that nano-filled LDPE may be for electric applications for which the dielectric materials may be exposed to partial discharge activities. This is significant result for the use of MgO-reinforced PE as an insulating material for HV cables since the resistance to PD is closely related to treeing resistance which is the main electrical degradation mechanism that leads to failure for shielded extruded power cables.

关键词： Low Density Polyethylene MgO Nanofillers Dielectric Strength Partial Discharges Resistance

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Repeatability and reproducibility of corneal higher-order aberrations measurements after small incision lenticule extraction using the Scheimpfug-Placido topographer

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Eye and Vision 2024年第1期10卷 1-9页

作者： Rui Ning Rongrong Gao david PPiñero Jun Zhang Qingyi Gao Yili Jin Yiran Wang Chenxiao Wang Jinhai Huang Eye Hospital and School of Ophthalmology and Optometry Wenzhou Medical UniversityWenzhouZhejiangChina Eye Institute and Department of Ophthalmology Eye and ENT HospitalFudan UniversityShanghaiChina Group of Optics and Visual Perception Department of OpticsPharmacology and AnatomyUniversity of AlicanteAlicanteSpain NHC Key Laboratory of Myopia(Fudan University) Key Laboratory of MyopiaChinese Academy of Medical SciencesShanghaiChina Shanghai Research Center of Ophthalmology and Optometry ShanghaiChina

Background:To evaluate the precision of corneal higher-order aberrations measurements after small incision lenticule extraction(SMILE)using the Sirius Scheimpfug-Placido topographer(CSO,Italy).Methods:Seventy-fve eyes from 75 postoperative subjects were included in this prospective *** consecutive corneal aberrometric measurements were obtained with the Scheimpfug-Placido topographer by two experienced operators to assess intra-and inter-observer *** within-subject standard deviation(Sw),test-retest repeatability(TRT)and the intraclass correlation coefcient(ICC)were ***:For intraobserver repeatability of anterior and total corneal aberrations,all ICCs were more than 0.922,except for trefoil(0.722 to 0.768).The ICCs of total root mean square(RMS),coma Z(3,±1),and spherical aberration Z(4,0)were over 0.810 while higher-order RMS,trefoil Z(3,±3),and astigmatism II Z(4,±2)were below 0.634 for posterior corneal surface *** Sw values for all types of aberrations were equal to or below 0.07μ*** interobserver reproducibility,all TRT values were no more than 0.12μm,0.05μm,and 0.11μm for anterior,posterior,and total corneal aberrations,*** ICC values ranged from 0.875 to 0.989,from 0.686 to 0.976 and over 0.834 for anterior,posterior,and total corneal aberrations,***:The repeatability of measurements of anterior and total corneal aberrations with the Sirius system in corneas after SMILE surgery was high,except for *** was some variability in posterior corneal aberrometric *** reproducibility of corneal aberrometric measurements was observed between measurements of both examiners,except for trefoil,with poor to moderate reproducibility.

关键词： Sirius Higher-order aberrations Repeatability Reproducibility Small incision lenticule extraction

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Rational molecular design of efficient yellow-red dendrimer TADF for solution-processed OLEDs: a combined effect of substitution position and strength of the donors

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Science China Chemistry 2024年第5期67卷 1613-1623页

作者： Changfeng Si Dianming Sun Tomas Matulaitis david B.Cordes Alexandra M.Z.Slawin Eli Zysman-Colman Organic Semiconductor Centre EaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsKY169STUK

The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red thermally activated delayed fluorescence(TADF) dendrimers that are solution-processable: 2GCz BP, 2DPACz BP, 2FBP2GCz and 2FBP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the optoelectronic properties. The reverse intersystem crossing rate constant(kRISC) of the emitters having donors substituted at positions 11and 12 of the dibenzo[a,c]phenazine(BP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACz BP, containing stronger donors than 2GCz BP, exhibits a red-shifted emission and smaller singlet-triplet energy splitting, ΔE_(ST), of 0.01 e V. The solution-processed OLED with 10 wt% 2DPACz BP doped in m CP emitted at 640 nm and showed a maximum external quantum efficiency(EQE_(max)) of 7.8%, which was effectively maintained out to a luminance of 1,000 cd m-2. Such a device's performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4Cz IPN as an assistant dopant in a hyperfluorescence(HF) configuration, where the 2DPACz BP HF device shows an EQEmaxof 20.0% at λEL of 605 nm and remains high at 11.8% at a luminance of 1,000 cd m-2, which makes this device one of the highest efficiency orange-to-red HF SP-OLEDs to date.

关键词： thermally activated delayed fluorescence solution-processing red OLEDs dibenzo[a,c]phenazine dendrimers

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