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Numerical Simulation of Turbulent Diffusion Flames of a Biogas Enriched with Hydrogen

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Fluid Dynamics & Materials Processing 2024年第1期20卷 79-96页

作者： Naima Krarraz Amina Sabeur Khadidja Safer Ahmed Ouadha Laboratoire des Science et Ingénierie Maritimes Facultéde Génie MécaniqueUniversitédes Sciences et de la Technologie d’Oran Mohamed BoudiafOranAlgérie Laboratoire des Carburants Gazeux et de l’Environnement Facultéde Génie MécaniqueUniversitédes Sciences et de la Laboratoire des Carburants Gazeux et de l’Environneme

Any biogas produced by the anaerobic fermentation of organic materials has the advantage of being an environmentally friendly ***,the relatively low calorific value of such gases makes their effective utilization in practical applications relatively *** present study considers the addition of hydrogen as a potential solution to mitigate this *** particular,the properties of turbulent diffusion jet flames and the related pollutant emissions are investigated numerically for different operating *** related numerical simulations are conducted by solving the RANS equations in the frame of the Reynolds Stress Model in combination with the flamelet *** effects are also taken into account and the combustion kinetics are described via the GRI-Mech 3.0 reaction *** considered hydrogen fuel enrichment spans the range from 0%to 50%in terms of *** varies between 1 and 10 *** results show that both hydrogen addition and pressure increase lead to an improvement in terms of mixing quality and have a significant effect on flame temperature and *** also reduce CO_(2) emissions but increase NOx *** NO is shown to be the predominant NO formation mechanism.

关键词： Biogas hydrogen diffusion flame turbulence NO formation route pressure

Virtual brain twins: from basic neuroscience to clinical use

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National Science Review 2024年第5期11卷 72-86页

作者： Huifang E.Wang Paul Triebkorn Martin Breyton Borana Dollomaja Jean-Didier Lemarechal Spase Petkoski Pierpaolo Sorrentino Damien Depannemaecker Meysam Hashemi Viktor K.Jirsa Aix Marseille Université Institut National de la Santéet de la Recherche Médicale Institut de Neurosciences des Systèmes(INS) UMR1106 Service de Pharmacologie Clinique et Pharmacosurveillance AP–HM

Virtual brain twins are personalized, generative and adaptive brain models based on data from an individual's brain for scientific and clinical use. After a description of the key elements of virtual brain twins,we present the standard model for personalized whole-brain network models. The personalization is accomplished using a subject's brain imaging data by three means:(1) assemble cortical and subcortical areas in the subject-specific brain space;(2) directly map connectivity into the brain models, which can be generalized to other parameters; and(3) estimate relevant parameters through model inversion, typically using probabilistic machine learning. We present the use of personalized whole-brain network models in healthy ageing and five clinical diseases: epilepsy, Alzheimer's disease, multiple sclerosis, Parkinson's disease and psychiatric disorders. Specifically, we introduce spatial masks for relevant parameters and demonstrate their use based on the physiological and pathophysiological hypotheses. Finally, we pinpoint the key challenges and future directions.

关键词： virtual brain twin personalized modeling inference neuroscience brain disorder

Fire and retention island remnants have similar deadwood carbon stock a decade after disturbances in boreal forests of Alberta

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Forest Ecosystems 2024年第5期11卷 677-684页

作者： Richard Osei Lance P.Moore Rosanise A.Odell Marcel Schneider Tanvir Ahmed Shovon Charles A.Nock Department of Renewable Resources University of AlbertaEdmontonCanada institut des sciences de La For^et Temperee Universite Du Quebec en Outaouais58 Rue PrincipaleRiponJ0V 1V0QCCanada

In an attempt to reconcile wood extraction and forest biodiversity in managed boreal forests,ecosystem-based forest management(EBM)has become the de facto management *** forestry represents one prominent way that EBM is implemented in many parts of the *** patches commonly left after harvesting serve as analogues of fire island remnants,which are patches of unburned forests in the burned forest *** the persistence of retention patches has been questioned,few studies have attempted to quantitatively compare forest attributes in both burned and harvested *** part of a larger program examining multiple aspects of ecosystem function in fire and harvest island remnants,we investigated the impact of disturbance type(fire/harvest)and forest edges on C stock in snags and coarse woody debris(CWD)found in island remnants in mixedwood boreal forests of Alberta,*** C stock(in snags and CWD)was similar between the two disturbance types and edge plots had similar total deadwood C stocks to *** edges of island remnants had about two-fold more snag C stock than their interiors in both disturbance types,but C stock in CWD was unaffected by edge effects and disturbance *** results suggest that deadwood C dynamics in island remnants in fire and harvest disturbed boreal forests were similar,thus lending support for the continued implementation of retention forestry in Alberta.

关键词： Retention forestry Deadwood Ecosystem-based management Wildfires Boreal forest

Minimal Legendrian surfaces in the tangent sphere bundle of R3

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Science China Mathematics 2024年第11期67卷 2607-2628页

作者： Mingyan Li Guofang Wang School of Mathematical sciences Ocean University of China Mathematisches institut Albert-Ludwigs-Universit?t Freiburg

In this paper,we study minimal Legendrian surfaces Σ immersed in the tangent sphere bundle *** classify(1) totally geodesic Legendrian surfaces,(2) closed minimal Legendrian surfaces of genus smaller than or equal to 1 and complete minimal Legendrian surfaces with the non-negative Gauss curvature,and(3) complete stable minimal Legendrian surfaces.

关键词： 53C24 53C42 classification Legendrian surface stable minimal surface tangent sphere bundle

Drought events influence nutrient canopy exchanges and green leaf partitioning during senescence in a deciduous forest

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Forest Ecosystems 2024年第1期11卷 110-119页

作者： J.Touche C.Calvaruso P.De Donato M.-P.Turpault INRAE BEFF-54000NancyFrance UMR 7359 GeoRessourcesFaculte des Sciences-Campus des Aiguillettes54506Vandoeuvre Les NancyFrance EcoSustain Environmental Engineering OfficeResearch and DevelopmentKanfen57330France

The increase in the frequency and intensity of drought events expected in the coming decades in Western Europe may disturb forest biogeochemical cycles and create nutrient deficiencies in *** possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption,foliar leaching and senesced ***,the effects of drought events on this partitioning and the consequences for the maintenance of tree nutrition are poorly *** experiment in a beech forest in Meuse(France)was conducted to assess the effect of drought events on nutrient canopy exchanges and on the partitioning of the green leaf pool during the leaf senescence *** aim was to identify potential nutritional consequences of droughts for *** nutrient dynamics,including resorption,chemistry of green and senesced leaves,foliar absorption and leaching in mature beech stands from 2012 to 2019 allowed us to compare the nutrient exchanges for three nondry and three dry years(i.e.,with an intense drought event during the growing season).During dry years,we observed a decrease by almost a third of the potassium(K)partitioning to resorption(*** efficiency),thus reducing the K reserve in trees for the next growing *** result suggests that with the increased drought frequency and intensity expected for the coming decades,there will be a risk of potassium deficiency in trees,as already observed in a rainfall exclusion experiment on the same study *** foliar leaching and higher parititioning to the senesced leaves for K and phosphorus(P)were also *** addition,a slight increase in nitrogen(N)resorption efficiency occurred during dry years which is more likely to improve tree *** calcium(Ca)negative resorption decreased,with no apparent consequence in our study *** results show that nutrient exchanges in the canopy and the partitioning of the green leaf

关键词： Natural drought Beech forest Canopy Resorption Foliar leaching Senesced leaves Nutrition

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Isometric Immersions of Lightlike Warped Product Manifolds

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Journal of Applied Mathematics and Physics 2024年第7期12卷 2490-2505页

作者： Domitien Ndayirukiye Cyriaque Atindogbe Gilbert Nibaruta Ecole Normale Suprieure Bujumbura Burundi institut des Mathmatiques et des sciences Physiques Universit dAbomey-Calavi Porto-Novo Bnin

In this paper, we deal with isommetric immersions of globally null warped product manifolds into Lorentzian manifolds with constant curvature c in codimension k≥3. Under the assumptions that the globally null warped product manifold has no points with the same constant sectional curvature c as the Lorentzian ambient, we show that such isometric immersion splits into warped product of isometric immersions.

关键词： Lightlike Warped Product Manifolds Globally Null Warped Products Manifolds Lightlike Warped Product Isometric Immersions

Spectroscopic Observations of Ten Galactic Wolf-Rayet Stars at Bosscha Observatory:Determination of Stellar Parameters and Mass-loss Rates

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Research in Astronomy and Astrophysics 2024年第9期24卷 7-27页

作者： Hakim Luthfi Malasan Bakuh Danang Setyo Budi Department of Astronomy Faculty of Mathematics and Natural SciencesInstitut Teknologi BandungBandung 40132Indonesia Bosscha Observatory Institut Teknologi BandungLembang 40391Indonesia Master Program in Astronomy Faculty of Mathematics and Natural SciencesInstitut Teknologi BandungJl.Ganesha No.10Bandung 40132Indonesia

We present optical spectra of 10 Galactic Wolf-Rayet(WR)stars that consist of five WN and five WC *** optical observation was conducted using a low-resolution spectrograph NEO-R1000(λ/Δλ~1000)at GAO-ITB RTS(27.94 cm,F/10.0),Bosscha Observatory,*** implemented stellar atmosphere Postdam Wolf-Rayet(PoWR)grid modeling to derive stellar *** normalized optical spectrum can be used to find the best model from the available PoWR grid,then we could derive stellar temperature and transformation *** derive luminosity,stellar radius and color excess,we conducted a Spectral Energy Distribution(SED)analysis with additional data on the near-ultraviolet spectrum from the International Ultraviolet Explorer(IUE)database,and UBV and 2MASS JHK broadband filter *** analysis to derive asymptotic terminal wind velocity was conducted from the P-Cygni profile analysis of the high-resolution IUE ultraviolet *** previously derived parameters,we could determine the mass loss rate of the WR ***,we compared our results with previous work that used PoWR code and the differences are not more than 20%.We conclude that the PoWR spectral grid is sufficient to derive WR stellar parameters quickly and could provide more accurate initial parameter input to the PoWR program code.

关键词： stars:massive stars:mass-loss stars:Wolf-Rayet stars:atmospheres stars:winds outflows

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Dynamic of Scalar Bosons in Aharonov-Bohm Magnetic Field

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Journal of Applied Mathematics and Physics 2024年第1期12卷 268-276页

作者： Frédéric D. Y. Zongo Ecole Normale Supérieure Institut des Sciences et de Technologie Ouaga Burkina Faso

We study the dynamic of scalar bosons in the presence of Aharonov-Bohm magnetic field. First, we give the differential equation that governs this dynamic. Secondly, we use variational techniques to show that the following Schrödinger-Newton equation: , where A is an Aharonov-Bohm magnetic potential, has a unique ground-state solution.

关键词： Scalar Boson Aharonov-Bohm Magnetic Field Schrödinger-Newton Equation Ground-State Solution

Influence of the Nature of the Incoming Sludge on the Performance of a Vertical Flow Reed Beds in Dakar-Senegal

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Journal of Water Resource and Protection 2024年第6期16卷 429-449页

作者： Elhadji Mamadou Sonko Diomaye Dieng Maïmouna Lo Cheikh Diop Laboratoire dEtude Environnemental des Milieux Urbains (LEEMUR) Institut des Sciences de lEnvironnement (ISE) Facult des Sciences et Technique (FST) Universit Cheikh Anta Diop de Dakar (UCAD) Dakar-Fann Sngal

This work investigates the influence of the type sludge on drainage, plant development, purification performances and biosolids quality. Drainage properties were measured through the frequency of clogging, the percentage of leachate recovered and the dryness of accumulated sludge. Plant development was measured through the density, the height and the stem diameter. Purification performance was evaluated from the reduction rate. Biosolids quality was measured after 3 months of maturation. The results show that the clogging frequencies were 9.5%;0% and 3.7%;the volume of leachate recovered was 42.2%;20.4% and 24.7% and, the dryness was 33.4%;61.1% and 52.4% for FS-ST, FS-STT and SS respectively. Plants densities were about, with densities 197.1, 171.3 and 178.3 plants/m2 in beds fed respectively with FS-ST, FS-STT and SS. despite the high removal rates, the concentrations of pollutants in the leachates are above the Senegalese standard NS 05-061 for discharge into the environment. The biosolids are all mature with C/N and NH4+/NO3?ratios lower than 12 and 1 respectively. The biosolids are also rich in organic and mineral elements. The concentrations of Ascaris eggs are higher than the WHO recommendations. These biosolids should be stored for additional time or composted.

关键词： Biosolid Quality Dewatering Performance Planted Drying Beds Purification Performance Sludge Type