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Prediction of Forming Limit Diagrams for materials with HCP Structure

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Acta metallurgica Sinica(English Letters) 2015年第12期28卷 1442-1451页

作者： Sheng-Hua Wu Nan-Nan Song francisco m.and.ad. pires Abel D.Santos Faculty of Engineering University of Porto INEGI University of Porto

The forming limit diagram（FLD） is an important tool to be used when characterizing the formability of metallic sheets used in metal forming processes. Experimental measurement and determination of the FLD is timeconsuming and therefore the analytical prediction based on theory of plasticity and instability criteria allows a direct and efficient methodology to obtain critical values at different loading paths, thus carrying significant practical ***, the accuracy of the plastic instability prediction is strongly dependent on the choice of the material constitutive model [1–3]. Particularly for materials with hexagonal close packed（HCP） crystallographic structure, they have a very limited number of active slip systems at room temperature and demonstrate a strong asymmetry between yielding in tension and compression [4, 5]. Not only the magnitude of the yield locus changes, but also the shape of the yield surface is evolving during the plastic deformation [4]. Conventional phenomenological constitutive models of plasticity fail to capture this unconventional mechanical behavior [4, 6]. Cazacu and Plunkett [6] have proposed generic yield criteria, by using the transformed principal stress, to account for the initial plastic anisotropy and strength differential（SD） effect simultaneously. In this contribution, a generic FLD mATLAB script was developed based on marciniak–Kuczynski analytical theory and applied to predict the localized necking. The influence of asymmetrical effect on the FLD was evaluated. Several yield functions such as von mises, Hill, Barlat89, and Cazacu06 were incorporated into analysis. The paper also presents and discusses the influence of different hardening laws on the formability of materials with HCP crystal structures. The findings indicate that the plastic instability theory coupled with Cazacu model can adequately predict the onset of localized necking for HCP materials under different strain paths.

关键词： Forming limit diagram(FLD) marciniak–Kuczynski analysis Plastic instability Yield function Hardening law

modulational Instability of Optical Vortices in Engineered Saturable media

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Engineering 2022年第10期17卷 31-43页

作者： D.G.pires N.m.Litchinitser Department of Electrical and Computer Engineering Duke UniversityDurhamNC 27708USA

Propagation of light beams in turbid media such as underwater environments,fog,clouds,or biological tissues finds increasingly important applications in science and technology,including bio-imaging,underwater communication,and free-space communication *** many of these applications traditionally relied on conventional,linearly polarized Gaussian beams,light possesses many degrees of freedom that are still largely unexplored,such as spin angular momentum(SAm)and orbital angular momentum(OAm).Here,we present nonlinear light-matter interactions of such complex light beams with"rotational"degrees of freedom in engineered nonlinear colloidal *** making use of both variational and perturbative approach,we consider non-cylindrical optical vortices,elliptical optical vortices,and higher-order Bessel beams integrated in time(HOBBIT)to predict the dynamics and stability of the evolution of these *** results may find applications in many scenarios involving light transmission in strongly scattering environments.

关键词： Optical vortex Orbital angular momentum modulation instability Turbid media

multi-conductor Line models for Harmonic Load-flow Calculations in LV Networks with High Penetration of PV Generation

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Journal of modern Power Systems and Clean Energy 2022年第5期10卷 1288-1301页

作者： Fernando m.Camilo m.E.Almeida Rui Castro V.Fernao pires Institutode Engenhariade Sistemas e Computadores Investigacao eDesenvolvimento(INESC-ID)and TecnicoUniversity of LisbonLisbonPortugal ESTSetubal Polytechnics of SetubalSetuibalPortugal

Low-voltage(LV) distribution networks are unbalanced and present loads with nonlinear behavior, which introduce harmonics in the networks. The predictable increase in photovoltaic microgeneration(PV μG) accentuates this unbalanced characteristic, as well as poses new technical problems,namely voltage rise and reverse power flow. To accurately account for the distributed PV and loads in the LV network, unbalanced three-phase power flow algorithms should be utilized,where different approaches may be used to represent lines with various degrees of accuracy. The more accurate algorithm considers the electromagnetic coupling between the line conductors,whereas the simpler algorithm represents each conductor of the line as a single-phase line with pure resistive behavior. This paper aims to analyze the influence of the line model on the load flow in a highly unbalanced LV network with a high penetration of PV production, and considers the impact of the harmonics produced by nonlinear loads. Based on the results obtained,it is possible to identify the most suitable model to be used, depending on the study to be performed. Different scenarios of PV generation and loads are addressed in this paper.

关键词： Line model nonlinear loads photovoltaic microgeneration unbalanced distribution network

Shear velocity criterion for incipient motion of sediment

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Water Science and Engineering 2014年第2期7卷 183-193页

作者： francisco J.m.SImOES U.S. Geological Survey Geomorphology and Sediment Transport LaboratoryGolden CO 80403 USA

The prediction of incipient motion has had great importance to the theory of sediment transport. The most commonly used methods are based on the concept of critical shear stress and employ an approach similar, or identical, to the Shields diagram. An alternative method that uses the movability number, defined as the ratio of the shear velocity to the particle＇s settling velocity, was employed in this study. A large amount of experimental data were used to develop an empirical incipient motion criterion based on the movability number. It is shown that this approach can provide a simple and accurate method of computing the threshold condition for sediment motion.

关键词： incipient motion sediment transport Shields diagram critical shear stress criticalshear velocity movability number

Dipole (hyper)polarizabilities of neutral silver clusters

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Chinese Physics B 2016年第12期25卷 217-222页

作者： francisco E Jorge Luiz G m de macedo Departarnento de Fisica Universidade Fedoral do Espirito Santo 29060-900 Vitoria Brazil Unidade Academica de Fisica Universidade Federal de Campina Grande 58429-900 Campina Grande Brazil Faculdade de Biotecnologia ICB Universidade Federal do Para 66075-110 Belem Brazil

At the Douglas-Kroll-Hess （DKI4） level, the B3PW91 functional along with the all-eleclron relativistic basis sets of valence triple and quadruple zeta qualities are used to determine the structure, stability, and electronic properties of the small silver clusters （Agn, n ≤ 7）. The results presented in this study are in good agreement with the experimental data and theoretical values obtained at a higher level of theory from the literature. Static polarizability and hyperpolarizability are also reported. It is verified that the mean dipole polarizability per atom exhibits an odd-even oscillation and that the polarizability anisotropy is directly related to the cluster shape. In this article, the first study of hyperpolarizabilities of small silver clusters is presented. Except for the monomer, the second hyperpolarizabilities of the silver clusters are significantly larger than those of the copper clusters.

关键词： B3PW91 functional all-electron basis sets non-relativistic and DKH2 calculations silver clusters,dipole (hyper)polarizabilities

Nanoparticle-encapsulated retinoic acid for the modulation of bone marrow hematopoietic stem cell niche

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Bioactive materials 2024年第4期34卷 311-325页

作者： Emanuel Quartin Susana Rosa Sara Gonzalez-Anton Laura mosteo Lopez Vitor francisco Delfim Duarte Cristina Lo Celso Ricardo pires das Neves Lino Ferreira CNC-Center for Neuroscience and Cell Biology CIBB-Centre for Innovative Biomedicine and BiotechnologyUniversity of Coimbra3004-517CoimbraPortugal IIIUC-Institute of Interdisciplinary Research University of Coimbra3004-517CoimbraPortugal Faculty of medicine University of Coimbra3004-517CoimbraPortugal Department of Life Sciences Imperial College LondonSouth Kensington CampusThe Francis Crick InstituteLondonUK Haematopoietic Stem Cell Laboratory The Francis Crick InstituteLondonUK Instituto de Investigação e Inovação em Saúde(i3S) University of PortoPortoPortugal Department of Biomedicine Faculdade de Medicina da Universidade do Porto(FMUP)PortoPortugal Department of Onco-Hematology Instituto Português de Oncologia(IPO)-PortoPortoPortugal

more effective approaches are needed in the treatment of blood cancers,in particular acute myeloid leukemia(AmL),that are able to eliminate resistant leukemia stem cells(LSCs)at the bone marrow(Bm),after a chemotherapy session,and then enhance hematopoietic stem cell(HSC)engraftment for the re-establishment of the HSC ***,we investigate whether light-activatable nanoparticles(NPs)encapsulating all-trans-retinoic acid(RA^(+)NPs)could solve both *** in vitro results show that mouse AmL cells transfected with RA^(+)NPs differentiate towards antitumoral m1 macrophages through RIG.1 and OASL gene *** in vivo results further show that mouse AmL cells transfected with RA^(+)NPs home at the Bm after transplantation in an AmL mouse *** photo-disassembly of the NPs within the grafted cells by a blue laser enables their differentiation towards a macrophage *** macrophage activation seems to have systemic anti-leukemic effect within the Bm,with a significant reduction of leukemic cells in all Bm compartments,of animals treated with RA^(+)NPs,when compared with animals treated with empty *** a separate group of experiments,we show for the first time that normal HSCs transfected with RA^(+)NPs show superior engraftment at the Bm niche than cells without treatment or treated with empty *** is the first time that the activity of RA is tested in terms of long-term hematopoietic reconstitution after transplant using an in situ activation approach without any exogenous priming or genetic conditioning of the transplanted ***,the approach documented here has the potential to improve consolidation therapy in AmL since it allows a dual intervention in the Bm niche:to tackle resistant leukemia and improve HSC engraftment at the same time.

关键词： Light Nanoparticles Retinoic acid Leukemia m1 macrophages Drug delivery

Stability analysis of slopes with planar failure using variational calculus and numerical methods

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Frontiers of Structural and Civil Engineering 2020年第5期14卷 1262-1273页

作者： Norly BELANDRIA RobertoÚCAR francisco m.LEON Ferri HASSANI Geological Engineering School University of Los AndesMérida 5101Venezuela mechanical Engineering School University of Los AndesMérida 5101Venezuela Department of mining and material Engineering McGill UniversityMontrealQC H3A 0E9Canada

This study investigates the technique of variational calculus applied to estimate the slope stability considering the mechanism of planar *** critical plane failure surface should be determined because it theoretically indicates the most unfavorable plane to be considered when stabilizing a slope to rectify the instability generated by several statistically possible *** generates integrals that can be solved by numerical methods,such as the Newton Cotes and the finite differences ***,a system of nonlinear equations is obtained and *** surface of the critical planar failure is determined by applying the condition of transversality in mobile boundaries,for which various examples are *** number of slices is varied in one of the examples,while the surface of the critical planar failure is determined in the *** are compared using analytical methods through axis *** the results obtained by considering normal stress,safety factors,and critical planar failure are nearly the same;however,in this research,a study is carried out for“n”number of slices using programming ***-routines are important because they can be applied in slopes with different geometry,surcharge,interstitial pressure,and pseudo-static load.

关键词： slopes stability planar failure variational calculus numerical methods

Decoupled Photovoltaic Power Ramp-rate Calculation method for Perturb and Observe Algorithms

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Journal of modern Power Systems and Clean Energy 2022年第4期10卷 932-940页

作者： Jose miguel Riquelme-Dominguez francisco m.Gonzalez-Longatt Sergio martinez Electrical Engineering Department Escuela Tecnica Superior de Ingenieros IndustrialesUniversidad Politecnica de Madrid28006 MadridSpain Department of Electrical Engineering Information Technology and CyberneticsUniversity of South-Eastern Norway3918 PorsgrunnNorway

As photovoltaic energy increasingly penetrates in power systems,transmission system operators have started to request its participation in providing ancillary *** of the demanded services is the power ramp-rate control(PRRC),which attempts to limit the power ramps produced by intermittent irradiance *** order to achieve the desired objective,solutions based on storage systems or modifying the maximum power point tracking(mPPT)in perturb and observe(P&O)algorithms are commonly *** starting point in PRRC is the determination of the instantaneous power ramprate,and different methods have been proposed in the literature for its ***,the accuracy and computational speed of existing procedures can be improved,which may be critical in situations with rapid irradiance *** this paper,a decoupled photovoltaic power ramp-rate calculation method is presented,in which the effect of variable irradiance and the P&O algorithm are computed *** proposed method has been theoretically demonstrated and tested through simulation and experimental *** results show that it can improve the previous methods in terms of accuracy and computation *** validation with hardware-inthe-loop demonstrates the suitability of the proposed method for real-time applications,even in presence of noisy measurements.

关键词： Hardware-in-the-loop maximum power point tracking perturb and observe photovoltaic power ramp-rate control ramp-rate calculation method

The differential genetic signatures related to climatic landscapes for jaguars and pumas on a continental scale

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Integrative Zoology 2021年第1期16卷 2-18页

作者： marina ZANIN Noa GONZALEZ-BORRAJO Cuauhtémoc CHÁVEZ Yamel RUBIO Bart HARmSEN Claudia KELLER Pablo VILLALVA Ana Carolina SRBEK-ARAUJO Leonora pires COSTA francisco PALOmARES Biology Department Federal University of MaranhãoSão LuísBrazil Departamento de Biologia de la Conservación Estación Biológica de DoñanaSevillaSpain Departamento de Ciencias Ambientales Universidad Autónoma MetropolitanaMexico CityMexico Escuela de Biologia Universidad Autónoma de SinaloaCuliacánMexico Panthera New YorkUSA Biodiversity Coordination Amazon Research InstituteManausBrazil Biology Department Vila Velha UniversityVila VelhaBrazil Biological Sciences Department Federal University of Espírito SantoVitóriaBrazil

modern and paleoclimate changes may have altered species dynamics by shifting species’niche suitability over space and *** analyze whether the current genetic structure and isolation of the two large American felids,jaguar(Panthera onca)and puma(Puma concolor),are mediated by changes in climatic suitability and connection routes over modern and paleoclimatic *** estimate species distribution under 5 climatic landscapes(modern,Holocene,last maximum glaciations[LmG],average suitability,and climatic instability)and correlate them with individuals’genetic isolation through causal modeling on a resemblance *** species exhibit genetic isolation patterns correlated with LmG climatic suitability,suggesting that these areas may have worked as“allele refuges.”However,the jaguar showed higher vulnerability to climate changes,responding to modern climatic suitability and connection routes,whereas the puma showed a continuous and gradual transition of genetic *** differential responsiveness to climate change,both species are subjected to the climatic effects on genetic configuration,which may make them susceptible to future climatic changes,since these are progressing faster and with higher intensity than changes in the ***,the effects of climatic changes should be considered in the design of conservation strategies to ensure evolutionary and demographic processes mediated by gene flow for both species.

关键词： causal modeling climatic landscape ecological niche modeling gene flow linear mixed model