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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 563-580页

作者： n.HUMnEKAR D.sRInIVAsACHARYA Department of Mathematics National Institute of TechnologyWarangal 506004TelanganaIndia

The influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel is *** DarcyBrinkman model is used to characterize the fluid flow dynamics in porous *** analytical solutions are obtained for the unidirectional and completely developed *** on a normal mode analysis,the generalized eigenvalue problem under a perturbed state is *** eigenvalue problem is then solved by the spectral ***,the critical Rayleigh number with the corresponding wavenumber is evaluated at the assigned values of the other flow-governing *** results show that increasing the Darcy number,the Lewis number,the Dufour parameter,or the soret parameter increases the stability of the system,whereas increasing the inclination angle of the channel destabilizes the ***,the flow is the most unstable when the channel is vertically oriented.

关键词： nanofluid inclined channel variable viscosity linear stability double dif-fusion porous medium

Influence of biomass burning on ozone levels in the Megalopolis of Central Mexico during the COVID-19 lockdown

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Journal of Environmental sciences 2024年第9期143卷 99-115页

作者： Victor Almanza Luis Gerardo Ruiz-suárez Ricardo Torres-Jardón Agustín García-Reynoso Iván Y.Hernández-Paniagua Institute for Atmospheric sciences and Climate Change National Autonomous University of MexicoCoyoacan 04510Mexico CityMexico

The massive reductions in anthropogenic emissions resulting from the COVID-19 lockdown provided a unique opportunity to evaluate the effect of mitigation measures aiming to abate air *** Mexico,the total lockdown period took place during the dry-hot season when biomass burning activity is ***,we investigate the role of biomass burning emissions on regional ozone levels in the Megalopolis of Central *** studied period covers the lockdown phases 2 and 3,and the first month of the new *** applied a factor separation technique and process analysis to estimate the pure and synergistic contributions of emission reductions under lockdown and that from biomass burning to daily ozone maximum concentrations in 7 metropolitan areas of different states in the *** results revealed that biomass burning plumes likely masked the effect of massive reductions from mobile emissions,impacted the PBL development during phase 3 and favored transition and mixed nO_(x)-limited and VOC-limited regional *** contributed to increased ozone production in the middle to lower PBL by changing the regional background levels which potentially could bias high ozone production efficiency *** the Megalopolis contribution to economic and societal development at national scale,our study suggests that ozone mitigation measures during the dry-hot season targeting mainly mobile emissions will likely be offset by biomass burning plumes.A regional and synergic policy aiming to control biomass burning would help to reduce the occurrence of high ozone levels in Central Mexico with the co-benefit of tackling short-lived climate pollutants.

关键词： COVID-19 Mexico Megalopolis Ozone Factor separation Process Analysis

Magnetic,dielectric and electrical modulus of Ce^(3+) doped cobalt-magnesium ferrite nanoparticles

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Journal of Rare Earths 2024年第2期42卷 373-382,I0005页

作者： n.M.Basfer Hanaa Almaghamsi Department of Physics Umm AL-Qura UniversityMakkahSaudi Arabia Physics Department College of Science and ArtKing Abdulaziz UniversityPOB344Rabigh291Saudi Arabi

In this work,the magnetic,dielectric properties and electric modulus of Ce^(3+) substituted cobaltmagnesium(Co_(0.7)Mg_(0.3)Ce_(x)Fe_(2-x)O_4)(labeled as CMCF) ferrite nanoparticles were investigated in *** magnetization decreases from 50.05 to 34.87 emu/g for further substituting Ce^(3+) ***,coercivity increases from 738.22 Gs for the CMCFO sample to 912.10 Gs for the CMCF2 sample,then decreases monotonically to 762.1 Gs for the CMCF5 *** cerium content and particle size play important roles in controlling the magnetization and coercivity of the CMCF *** CMCF nanoferrites are suitable for microwave applications since their high-frequency response ranges from 7.72 to 11.07 *** CMCF nanoferrites' dielectric parameter dispersion exhibits normal *** pristine Co-Mg nanoferrite only has ε' value of 28.25,but the nanoferrite MCMF2 has ε' value of365.03,with an enhancing ratio of 1192%.The conduction mechanism of the MCMF nanoferrites was determined by fitting the σ_(ac) results via the Jonscher power *** 653 K,large polaron tunnelling is thought to be responsible for this conduction process,which is followed by electron barrier hopping at higher ***-Cole diagrams at different temperatures,assuring the contributions of the grains and their boundaries at lower temperatures(653 K) and only the grains at higher *** on our results,the CMCF nanoferrites hold magnetic and semiconducting nature,which can be used in magnetic devices and dielectrics in lower-frequencies or conductors in higher-frequencies.

关键词： nanoferrites Rare earth ions Magnetic properties Dielectric parameters Impedance spectroscopy

Comprehensive analysis of uncertainty quantification for the^(58)ni(n,p)^(58)Co reaction cross section

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Chinese Physics C 2024年第9期48卷 170-175页

作者： Mahesh Choudhary Aman sharma namrata singh Mahima Upadhyay Punit Dubey A.Gandhi Akash Hingu G Mishra sukanya De L.s.Danu Ajay Kumar R.G.Thomas saurav sood sajin Prasad s.Mukherjee I.n.Ruskov Yu.n.Kopatch A.Kumar Department of Physics Banaras Hindu UniversityVaranasi 221005India Horia Hulubei national Institute of Physics and nuclear Engineering-IFIn-HH Bucharest 077125Romania Department of Physics The Maharaja Sayajirao University of BarodaVadodara 390002India nuclear Physics Division Bhabha Atomic Research CentreMumbai 400085India Health Physics Division Bhabha Atomic Research CentreMumbai 400085India Department of Electrical Power Engineering Brno University of TechnologyBrno 61600Czech Republic Institute for nuclear Research and nuclear Energy Bulgarian Academy of SciencesSofia 1784Bulgaria Joint Institute for nuclear Research(JInR) Dubna 141980Russia

In this study,we measured the^(58)ni(n,p)^(58)Co reaction cross section with neutron energies of 1.06,1.86,and 2.85 *** cross section was measured using neutron activation techniques andγ-ray spectroscopy,and it was compared with cross section data available in the ***,we calculated the covariance matrix of the measured cross section for the aforementioned nuclear *** uncertainties of the theoretical calculation for^(58)ni(n,p)^(58)Co reaction cross section were calculated via Monte Carlo *** this study,we used uncertainties in the optical model and level density parameters to calculate uncertainties in the theoretical cross *** theoretical calculations were performed by using *** this study,we aim to analyze the effect of uncertainties of the nuclear model input as well as different experimental variables used to obtain the values of reaction cross section.

关键词： ^(58)ni(n p)^(58)Co reaction γ-ray spectroscopy uncertainty quantification of cross section covariance analysis

structural stability of the Financial Market Model: Continuity of superhedging Price and Model Approximation

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Journal of the Operations Research society of China 2024年第1期12卷 215-241页

作者： sergey n.smirnov Faculty of Computational Mathematics and Cybernetics Lomonosov Moscow State UniversityMoscow119991Russian Federation

The present paper continues the topic of our recent paper in the same journal,aiming to show the role of structural stability in financial *** the context of financial market modeling,structural stability means that a specific“no-arbitrage”property is unaffected by small(with respect to the Pompeiu–Hausdorff metric)perturbations of the model’s *** formulate,based on our economic interpretation,a new requirement concerning“no arbitrage”properties,which we call the“uncertainty principle”.This principle in the case of no-trading constraints is equivalent to structural *** demonstrate that structural stability is essential for a correct model approximation(which is used in our numerical method for superhedging price computation).We also show that structural stability is important for the continuity of superhedging prices and discuss the sufficient conditions for this continuity.

关键词： Uncertainty structural stability no arbitrage Continuity of superhedging price Compact-valued multifunction Financial market model approximation Trading constraints

Maximizing aged photovoltaic array power:a computer modelling study

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Clean Energy 2024年第1期8卷 171-187页

作者： Fadi n.sibai Electrical&Computer Engineering Department Gulf University for Science and TechnologyMishrefKuwait

Photovoltaic(PV)modules age with time for various reasons such as corroded joints and terminals and glass coating defects,and their ageing degrades the PV array *** the help of the PV array numerical model,this paper explores the effects of PV module ageing on the PV array power,and the power gains and costs of rearranging and recabling aged PV modules in a PV *** numerical PV array model is first revised to account for module ageing,rearrangement and recabling,with the relevant equations presented *** updated numerical model is then used to obtain the array powers for seven different PV *** power results are then analysed in view of the attributes of the seven PV array examples.A guiding method to recommend recabling after rearranging aged modules is then proposed,leading to further significant power gains,while eliminating intra-row *** certain conditions are met,it was shown that recabling PV modules after rearranging them may lead to further significant power gains,reaching 57%and 98%in two considered PV array *** gains are possible in other arrays.A cost-benefit analysis weighing annual power gains versus estimated recabling costs is also given for the seven considered PV array examples to guide recabling decisions based on technical and economic *** the considered examples,recabling costs can be recovered ins of the aged arrays,power gains due to our proposed rearranging and recabling the PV arrays ranged between 73%and 131%in the considered examples—well over the gains reported in the ***,the cost of our static module rearrangement and recabling method outshines the costs of dynamic reconfiguration methods recently published in the literature.

关键词： solar energy optimizing array power photovoltaic array modelling photovoltaic modules ageing photovoltaic module rearrangement module recabling and reconfiguration PV array mismatch

Predicting uniaxial compressive strength of tuff after accelerated freeze-thaw testing: Comparative analysis of regression models and artificial neural networks

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Journal of Mountain science 2024年第10期21卷 3521-3535页

作者： Ogün Ozan VAROL Department of Mining Engineering Faculty of EngineeringVan Yuzuncu Yil UniversityVan 65080Türkiye

Ignimbrites have been widely used as building materials in many historical and touristic structures in the Kayseri region of Türkiye. Their diverse colours and textures make them a popular choice for modern construction as well. However, ignimbrites are particularly vulnerable to atmospheric conditions, such as freeze-thaw cycles, due to their high porosity, which is a result of their formation process. When water enters the pores of the ignimbrites, it can freeze during cold weather. As the water freezes and expands, it generates internal stress within the stone, causing micro-cracks to develop. Over time, repeated freeze-thaw (F-T) cycles lead to the growth of these micro-cracks into larger cracks, compromising the structural integrity of the ignimbrites and eventually making them unsuitable for use as building materials. The determination of the long-term F-T performance of ignimbrites can be established after long F-T experimental processes. Determining the long-term F-T performance of ignimbrites typically requires extensive experimental testing over prolonged freeze-thaw cycles. To streamline this process, developing accurate predictive equations becomes crucial. In this study, such equations were formulated using classical regression analyses and artificial neural networks (Ann) based on data obtained from these experiments, allowing for the prediction of the F-T performance of ignimbrites and other similar building stones without the need for lengthy testing. In this study, uniaxial compressive strength, ultrasonic propagation velocity, apparent porosity and mass loss of ignimbrites after long-term F-T were determined. Following the F-T cycles, the disintegration rate was evaluated using decay function approaches, while uniaxial compressive strength (UCs) values were predicted with minimal input parameters through both regression and Ann analyses. The Ann and regression models created for this purpose were first started with a single input value and then dev

关键词： Ignimbrite Uniaxial compressive strength Freeze-thaw Decay function Regression Artificial neural network

Assessment of CO_(2)storage prospect based on physical properties of Rio Bonito Formation rock units

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Energy Geoscience 2024年第1期5卷 321-330页

作者： Richardson M.Abraham-A stephanie san Martín Cañas Isabella F.s.Miranda Colombo C.G.Tassinari Institute of Energy and Environment(IEE) University of São Paulo(USP)Brazil Research Centre for Greenhouse Gas Innovation(RCGI) University of Sãao Paulo(USP)Brazil

The physical properties of the rock units associated with the Rio Bonito Formation are presented in this study with the focus on modelling reservoir quality based on petrophysics-derived parameters to evaluate CO_(2)storage *** involves the modelling of the reservoir depths,thicknesses,flow zone indicators(FZI),and effective permeability(Keff)and presenting the CO_(2)storage efficiency factors peculiar to the rock units of the study *** results presented by this study for the stated objectives are not quite common in the *** values range from 200 mD to higher than 2000 mD,and FZI values are generally above 1.0 mm and up to 13.0 mm within the portions covered by the drilled *** sandstone units recorded are up to 20 m thick in some *** Keff and FZI models indicate the sandstone reservoirs as permeable units to support the injection and circulation of CO_(2)within the potential reservoir units of the Rio Bonio Formation across são Paulo *** from some points in the southeastern part of the study location,where the Rio Bonito are delineated at depths less than 800 m(minimum CO_(2)storage depth based on best practices),other portions are deeper,ranging from 950 m to 3500 ***-bedded layers will affect the integrity of the rocks as CO_(2)storage tanks or reservoir seals/traps/overburden within the *** bed thicknesses are up to 20 m in some ***,hybrid CO_(2)reservoir units are feasible,especially in portions where thin siltstone layers are sandwiched between sandstone units to provide considerable thicknesses based on CO_(2)storage *** current study shows that useable areas considering reservoir thickness,depth,and other physical qualities will significantly control the CO_(2)storage efficiency of the study *** studies featuring a detailed geophysical exploration of the site to confirm the availability and saturations of preexisting fluid(hydrocarbon and water)are encouraged

关键词： Rio Bonito Effective permeability Fluid transmissibility CO_(2)storage prospect Reservoir quality Overburden integrity Flow zones

Unravelling COVID-19 waves in Rio de Janeiro city:Qualitative insights from nonlinear dynamic analysis

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Infectious Disease Modelling 2024年第2期9卷 314-328页

作者： Adriane s.Reis Laurita dos santos Américo Cunha Jr Thaís C.R.O.Konstantyner Elbert E.n.Macao Institute of science and Technology Federal University of São PauloSão Josédos CamposSPBrazil Physics Institute University of São PauloSão PauloSPBrazil scientific and Technological Institute Universidade BrasilSão PauloSPBrazil Department of Applied Mathematics Rio de Janeiro State UniversityRio de JaneiroRJBrazil Paulista school of Medicine Federal University of São PauloSão PauloSPBrazil

since the COVID-19 pandemic was first reported in 2019,it has rapidly spread around the *** countries implemented several measures to try to control the virus *** healthcare system and consequently the general quality of life population in the cities have all been significantly impacted by the Coronavirus *** different waves of contagious were responsible for the increase in the number of cases that,unfortunately,many times lead to *** this paper,we aim to characterize the dynamics of the six waves of cases and deaths caused by COVID-19 in Rio de Janeiro city using techniques such as the Poincaréplot,approximate entropy,second-order difference plot,and central tendency *** results reveal that by examining the structure and patterns of the time series,using a set of non-linear techniques we can gain a better understanding of the role of multiple waves of COVID-19,also,we can identify underlying dynamics of disease spreading and extract meaningful information about the dynamical behavior of epidemiological time *** findings can help to closely approximate the dynamics of virus spread and obtain a correlation between the different stages of the disease,allowing us to identify and categorize the stages due to different virus variants that are reflected in the time series.

关键词： COVID-19 nonlinear analysis Poincaréplot Central tendency measure

Antibiotic ciprofloxacin removal from aqueous solutions by electrochemically activated persulfate process:Optimization,degradation pathways,and toxicology assessment

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Journal of Environmental sciences 2024年第9期143卷 85-98页

作者： Elif Yakamercan Ahmet Aygün Halis simsek Environmental Engineering Department Bursa Technical UniversityBursaTurkey Agricultural and Biological Engineering Department Purdue UniversityWest LafayetteINUSA

Ciprofloxacin(CIP)is a commonly used antibiotic in the fluoroquinolone group and is widely used in medical and veterinary medicine disciplines to treat bacterial *** CIP is discharged into the sewage system,it cannot be removed by a conventional wastewater treatment plant because of its recalcitrant *** this study,boron-doped diamond anode and persulfate were used to degrade CIP in an aquatic solution by creating an electrochemically activated persulfate(EAP)*** added to the system as a coactivator and the process was called EAP+*** effects of independent variables,including pH,Fe^(2+),persulfate concentration,and electrolysis time on the systemwere optimized using the response surface *** results showed that the EAP+Fe process removed 94%of CIP under the following optimum conditions:A pH of 3,persulfate/Fe^(2+)concentration of 0.4 mmol/L,initial CIP concentration 30 mg/L,and electrolysis time of 12.64 *** removal efficiency was increased from 65.10%to 94.35%by adding Fe^(2+)as a transition *** degradation products,7 pathways,and 78 intermediates of CIP were studied,and three of those intermediates(m/z 298,498,and 505)were *** toxicological analysis based on toxicity estimation software results indicated that some degradation products of CIP were toxic to targeted animals,including fathead minnow,Daphnia magna,Tetrahymena pyriformis,and *** optimumoperation costswere similar in EAP and EAP+Fe processes,approximately 0.54€/m^(3).

关键词： Ciprofloxacin Response surface methodology Electrochemically activated persulfate Electrooxidation