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A Boundary Meshless Method for solving Heat Transfer Problems Using the Fourier Transform

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Advances in Applied Mathematics and Mechanics 2011年第5期3卷 572-585页

作者： A.Tadeu C.s.Chen J.antonio Nuno simoes Department of Civil Engineering Faculty of Sciences and TechnologyUniversity of CoimbraPolo II-Pinhal de Marrocos3030-290 CoimbraPortugal Department of Mathematics University of Southern MississippiHattiesburgMS 39406USA

Fourier transform is applied to remove the time-dependent variable in the diffusion *** non-harmonic initial conditions this gives rise to a non-homogeneous Helmholtz equation,which is solved by the method of fundamental solutions and the method of particular *** particular solution of Helmholtz equation is available as shown in[4,15].The approximate solution in frequency domain is then inverted numerically using the inverse Fourier transform *** frequencies are used in order to avoid aliasing phenomena and to allow the computation of the static *** numerical examples are given to illustrate the effectiveness of the proposed approach for solving 2-D diffusion equations.

关键词： Transient heat transfer meshless methods method of particular solutions method of fundamental solutions frequency domain Fourier transform

Geotechnical particle finite element method for modeling of soilstructure interaction under large deformation conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第3期14卷 967-983页

作者： Josep Maria Carbonell Lluís Monforte Matteo O.Ciantia Marcos Arroyo antonio Gens MECAMAT Group Department of EngineeringFaculty of Science and TechnologyUniversitat de Vic-Universitat Central de Catalunya(UVic-UCC)VicSpain Centre Internacional de Mètodes Numèrics a l'Enginyeria(CIMNE) BarcelonaSpain school of science and Engineering University of DundeeDundeeUK Universitat Politècnica de Cataluna-BarcelonaTech BarcelonaSpain

The possibilities of the particle finite element method(PFEM)for modeling geotechnical problems are increasingly *** is a numerical approach to solve large displacement and large strain continuum problems that are beyond the capabilities of classical finite element method(FEM).In PFEM,the computational domain is reconfigured for optimal solution by frequent remeshing and boundary *** inherits many concepts,such as a Lagrangian description of continuum,from classic geomechanical *** familiarity with more popular numerical methods facilitates learning and *** work focuses on G-PFEM,a code specifically developed for the use of PFEM in geotechnical *** article has two *** first is to give the reader an overview of the capabilities and main features of the current version of the G-PFEM and the second is to illustrate some of the newer developments of the code.G-PFEM can solve coupled hydro-mechanical static and dynamic problems involving the interaction of solid and/or deformable *** constitutive models for geomaterials are available,including features,such as structure and destructuration,which result in brittle *** solutions are robust,solidly underpinned by numerical technology including mixedfield formulations,robust and mesh-independent integration of elastoplastic constitutive models and a rigorous and flexible treatment of contact *** novel features presented in this work include the contact domain technique,a natural way to capture contact interactions and impose contact constraints between different continuum bodies,as well as a new simplified formulation for dynamic impact *** code performance is showcased by the simulation of several soil-structure interaction problems selected to highlight the novel code features:a rigid footing insertion in soft rock,pipeline insertion and subsequent lateral displacement on over-consolidated clay,screw-pile pull-out and the dyn

关键词： Particle finite element method(PFEM) structured soils Nonlocal elastoplasticity Contact domain method soil penetration problems

Innovative treatments for congenital heart defects

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World Journal of Pediatrics 2023年第1期19卷 1-6页

作者： antonio F.Corno Taylor s.Koerner Jorge D.salazar McGovern Medical school Children's Heart InstituteMemorial Hermann Children's HospitalUniversity of Texas Health Science Center in Houston6410 Fannin StreetMSB 6.274HoustonTX 77030USA

The past few decades have witnessed substantial advances in the treatment of complex congenital heart defects,with most significant advances in surgical treatment strategies and improved outcomes dependent upon well-educated and calculated risk-taking *** the present surgical era,doing nothing for complex congenital heart defects is unacceptable,and pioneering surgeons are willing to under-take and accept the substantial risks of innovative pediatric cardiac surgery[1].

关键词： congenital treatment defects

Magnetic field assisted fluidization:A modified Richardson-Zaki equation

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China Particuology 2007年第1期5卷 61-70页

作者： Jose Manuel Valverde antonio Castellanos Faculty of Physics Universidad de Sevilla Avenida Reina Mercedes s/n 41012 Sevilla Spain

Magnetic particles can be uniformly fluidized by coupling the gas flow with an externally imposed magnetic field. Interparticle forces generated by the magnetic field cause aggregation of the particles in chain-like structures preferentially oriented along the magnetic field lines. In the present paper, we study the implications of the formation of these special types of aggregates on the empirical Richardson-Zaki （RZ） equation, originally proposed to describe the expansion of fluidized beds of non-aggregated particles. We have addressed two important issues, namely the flow regime, which is a function of the size of the aggregates, and the effect of shape and orientation of the chain-like aggregates with respect to gas flow on fluid drag. We propose a modified RZ equation （MRZE） in which the velocity scale, given by the terminal settling velocity of the individual aggregates, and the RZ exponent are predetermined as a function of the chain length. The chain length depends on the ratio of the magnetic energy to gravitational energy, and is estimated from the magnetic field intensity, and particle magnetization, size and density. Predictions of the MRZE are successfully compared with published results in the literature on the expansion of magnetic particles in the presence of externally applied magnetic fields.

关键词： Fluidization Geldart B Magnetic particles Aggregation Richardson-Zaki equation

Phenomenological model for torsional galloping of an elastic flat plate due to hydrodynamic loads

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Journal of Hydrodynamics 2014年第1期26卷 57-65页

作者： FERNANDEs antonio Carlos ARMANDEI Mohammadmehdi Department of Naval and Ocean Engineering COPPE/UFRJ

This study investigates the torsional galloping phenomenon, an instability type flow-induced oscillation, in an elastic stru-cture due to hydrodynamic loads into the water current. The structure applied here is a rectangular flat plate with an elastic axis in its mid-chord length. The elasticity is provided by torsion spring. The flat plate has only one degree of freedom which is rotation in pure yaw about its axis. It is observed that as the current speed is higher than a critical velocity, the flat plate becomes unstable. The instability leads to torsional galloping occurrence, as a result of which the flat plate begins to yaw about the elastic axis. By testing two different chord lengths each with several torsion spring rates, the flat plate behavior is investigated and three different responses are recognized. Then, a phenomenological model is developed with the original kernel in the form of the van der Pol-Duffing equa-tion. The model explains these three responses observed experimentally.

关键词： torsional galloping flow-induced oscillation phenomenological model van der Pol-Duffing equation

stability analysis of the fluttering and autorotation of flow-induced rotation of a hinged flat plate

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Journal of Hydrodynamics 2013年第5期25卷 755-762页

作者： MIRZAEIsEFAT sina FERNANDEs antonio Carlos Department of Naval Architecture and Marine Engineering University of Michigan COPPE/UFRJ Federal University of Rio de Janeiro

This work describes investigations performed on the interaction of uniform current and freely rotating plate about a fixed vertical axis. Fluttering and autorotation are two different motions that may occur during the flow induced rotation. The dimensional analysis proves that the motion in flow induced rotation motion is governed essentially by the dimensionless moment of inertia and Reynolds number. Certain combinations define the stability boundaries between fluttering and autorotation. Fluttering is oscillation of body about a vertical axis and the autorotation is a name given to the case when the body turns continuously about the vertical axis First, the loads and moment coefficients are calculated by experiments and streamline theory for different angles of attack for a fixed fiat plate. Then for dynamic case, a bifurcation diagram is presented based on experiments to classify different motion states of flow induced rotation. Finally, a dynamical model is proposed for stability analysis of flow induced rotation of a flat plate.

关键词： flow-induced rotation autorotation fluttering stability analysis

CRIsPR-Cas-based plant genome engineering goes viral

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Molecular Plant 2023年第4期16卷 660-661页

作者： Jose-antonio Daros Fabio Pasin Fernando Merwaiss Instituto de Biologia Molecular y Celular de Plantas(CsiC-Universitat Politecnica deValencia) 46022ValenciaSpain

Biotechnological advances in the field of plant biology based on the bacterial and archaeal CRisPR-Cas systems promise a new generation of crop plants that are more productive and nutritive,resistant to pest and pathogens,and better adapted to environmental ***,application of this technology in plants still encounters some burdens,especially related to the expression of the CRIsPR-Cas reaction components in plant cells.

关键词： plant CRIsPR adapted

Litter production and leaf nutrient concentration and remobilization in response to climate seasonality in the central Amazon

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Journal of Forestry Research 2024年第3期35卷 131-141页

作者： Ricardo antonio Marenco saul Alfredo Antezana-Vera Daniela Pereira Dias Luiz antonio Candido Instituto Nacional de Pesquisas da Amazonia Coordenagao de Uso da Terra e Mudanca ClimaticaAv.Andre Araujo 2936ManausAM69067-375Brazil Programa de pos-Graduagao em Agricultura no Tropico Umido Instituto Nacional de Pesquisas da Amazonia-INPAManausAMBrazil Unidade Academica de Ciencias Agrarias Universidade Federal de JataiBR 364km 195JataiGO 75801-615Brazil

Litterfall is the largest source of nutrients to for-est soils of tropical ***,variability in lit-terfall production,nutrient remobilization,and changes in leaf nutrient concentration with climate seasonality remain largely unknown for the central *** study meas-ured litterfall production,leaf nutrient remobilization,and leaf area index on a forest plateau in the central *** was measured at monthly intervals during 2014,while nitrogen,phosphorus,potassium,calcium and mag-nesium concentrations of leaf litter and canopy leaves were measured in the dry and rainy seasons,and remobilization rates *** area index was also recorded in the dry and rainy *** litterfall varied from 33.2(in the rainy season)to 87.6 g m^(-2) in the dry season,while leaf area index increased slightly in the rainy *** seasonality had no effect on concentrations of nitrogen,calcium,and magnesium,whereas phosphorous and potassium responded to rainfall seasonality *** phosphorous increased,potassium decreased during the dry *** seasons,nitrogen,potassium,and phosphorous decreased in leaf litter;calcium increased in leaf litter,while magnesium remained unaffected with leaf ***,the five nutrients had similar remobilization rates over the *** absence of climate seasonality on nutrient remobilization suggests that the current length of the dry season does not alter nutrient remobilization rates but this may change as dry periods become more prolonged in the future due to climate change.

关键词： Throughfall Nutrient cycling Climatic seasonality Leaf mass per area

seismic performance of a reinforced concrete building retrofitted with self-centering shape memory alloy braces

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Earthquake Engineering and Engineering Vibration 2022年第3期21卷 785-809页

作者： Massimiliano Ferraioli antonio Concilio Carmine Molitierno Department of Engineering University of Campania“Luigi Vanvitelli”via Roma 2981031 Aversa(CE)Italy Adaptive structures Div. the Italian Aerospace Research Centre(CIRA)via Maiorise81043 Capua(CE)Italy Department of structures for Engineering and Architecture University of Naples“Federico Ⅱ”via Claudio 2180125NapoliItaly

self-centering earthquake-resistant structures have received increased attention due to their ability to reduce post-earthquake residual deformations and,thus,repair time and *** stimulated the development of recentering shape memory alloy(sMA)dampers that use superelastic nitinol wires to dissipate energy and self-center the ***,there are still a few case studies applications on full-scale RC buildings in the ***,general guidelines or even simplified approaches for the practical design of sMA damped braces are still *** paper focuses on evaluating the effect of using self-centering shape memory alloy dampers for buckling-restrained braces applied for the seismic retrofit of a complex RC building structure.A design method originally proposed for elastoplastic dampers was implemented to size the sMA dampers to be placed on selected spans and stories of a *** effectiveness of the design procedure was demonstrated by nonlinear time-history analyses under different sets of earthquake strong ground *** analysis results show that the recentering shape memory alloy bracing system is effective in limiting the maximum transient inter-story drifts and reducing the residual inter-story drifts after strong seismic events,due to its excellent recentering behavior together with its not negligible energy dissipation capacity.

关键词： RC buildings seismic retrofit buckling-restrained braces shape memory alloys dampers self-centering