FIC/FEM formulation with matrix stabilizing terms for incompressible flows at low and high Reynolds numbers

The final publication is available at Springer via http://dx.doi.org/10.1007/s00466-006-0060-yWe present a general formulation for incompressible fluid flow analysis using the finite element method. The necessary stabilization for dealing with convective effects and the incompressibility condition are introduced via the Finite Calculus method using a matrix form of the stabilization parameters. This allows to model a wide range of fluid flow problems for low and high Reynolds numbers flows without introducing a turbulence model. Examples of application to the analysis of incompressible flows with moderate and large Reynolds numbers are presented.Peer ReviewedPostprint (author's final draft

Plasmid-Based DNA Vaccines

Plasmids are circular deoxyribonucleic acid (DNA) vectors that can be used as vaccines to prevent various types of diseases. These plasmids are DNA platforms that are usually composed of a viral promoter gene, a gene coding resistance to antibiotics, a bacterial origin of replication gene and a multiple cloning site (MCS) for a transgenic region, where one or several genes of antigenic interest can be inserted. Immunization with these recombinant vectors allows intracellular expression of the encoded antigens by molecular and cellular machinery of transfected cells, stimulating an antigen-specific immune response. This process provides an effective protection against diverse types of pathogens, tumor cells and even allergy and autoimmune diseases. Protective efficacy is achieved by the induction of a strong humoral and cellular immune response dependent on B and T cells. The immunity induced by these DNA vaccines, added to the ease of production, administration, genetic stability, and safety, has transformed plasmid-based immunization into a safe strategy in prevention of various diseases

CIMNE Verification of the validation analysis of Xfinas elements database

In order to validate the Xfinas code a very comprehensive series of test examples were solved by Prof Ki-Du Kim and his co-workers. A collection of the more representative benchmarks were chosen at CIMNE for testing the good behavior of every element implemented in the software. The aim of the validation work carried out at CIMNE has been to asses the accuracy of the Xfinas program. This was done studying the whole validation process carried out by Prof Ki-Du Kim’s team in detail. For this purpose we have chosen at CIMNE randomly the different benchmarks to be reproduced between those of the validation manual (VM from now on). In every example we checked the agreement of the results with the Xfinas validation data

A four-noded quadrilateral element for composite laminated plates/shell using the refined zigzag theory

A new bilinear 4-noded quadrilateral element (called QLRZ) for the analysis of composite laminated and sandwich plates/shells based on the refined zigzag theory (RZT) proposed by Tessler et al. [1] is presented. The element has seven kinematic variables per node. Shear locking is avoided by introducing an assumed linear shear strain field. The performance of the element is studied in several examples where the reference solution is the 3D finite element analysis using 20-noded hexahedral elements. Finally, the capability for capturing delamination effects is analyzed

A four‐noded quadrilateral element for composite laminated plates/shells using the refined zigzag theory

A new bilinear four‐noded quadrilateral element (called quadrilateral linear refined zigzag) for the analysis of composite laminated and sandwich plates/shells based on the refined zigzag theory is presented. The element has seven kinematic variables per node. Shear locking is avoided by introducing an assumed linear shear strain field. The performance of the element is studied in several examples where the reference solution is the 3D finite element analysis using 20‐noded hexahedral elements

A numerical model of delamination in composite laminated beams using the LRZ beam element based on the refined zigzag theory

A method based on the Refined Zigzag Theory (RZT) to model delamination in composite laminated beam structures is presented. The novelty of this method is the use of one-dimensional finite elements to discretize the geometry of the beam. The key property of this beam element, named LRZ, is the possibility to capture the relative displacement between consecutive layers which occurs during delamination. The fracture mode that the LRZ element is capable to predict is mode II. In order to capture the relative displacement using the LRZ element it is necessary to adapt the RZT theory as presented in this paper. The mechanical properties of the layers are modeled using a continuum isotropic damage model. The modified Newton–Raphson method is used for solving the non-linear problem. The RZT theory, the LRZ finite element and the isotropic damage model are described in the paper. Also, the implicit integrations algorithm is presented. The performance of the LRZ element is analyzed by studying the delamination in a beam for two different laminates, using the plane stress solution as a reference

Two-noded beam element for composite and sandwich beams using Timoshenko theory and refined zigzag kinematics

The so-called zigzag theory has been developed in recent years as an extension of the classical layer-wise theory for modeling composite laminated beams, plates and shells. An advantage of the zigzag theory is that the number of kinematic variables is independent of the number of layers. In this work we present a simple linear two-noded beam element adequate for the analysis of composite and sandwich beams based on the combination of classical Timoshenko beam theory and the refined zigzag kinematics recently proposed by Tessler et al. [19]. The accuracy of the new beam element is tested in a number of examples of applications for composite laminated beams

A four-noded quadrilateral element for composite laminated plates/shell using the refined zigzag theory

A new bilinear 4-noded quadrilateral element (called QLRZ) for the analysis of composite laminated and sandwich plates/shells based on the refined zigzag theory (RZT) proposed by Tessler et al. [1] is presented. The element has seven kinematic variables per node. Shear locking is avoided by introducing an assumed linear shear strain field. The performance of the element is studied in several examples where the reference solution is the 3D finite element analysis using 20-noded hexahedral elements. Finally, the capability for capturing delamination effects is analyzed

Osmium-mediated direct C–H bond activation at the 8-position of quinolines

Metal-mediated direct C–H bond activation at the 8-position of quinolines, which is the essential step for the functionalization of this bond, is promoted by the hexahydride OsH6(PiPr3)2. This complex activates quinoline and 2-, 3-, 6-, and 7-methylquinoline to afford the classical trihydride derivatives OsH3{κ2-C8,N-(quinolinyl)}(PiPr3)2 and OsH3{κ2-C8,N-(quinolinyl-n-Me)}(PiPr3)2 (n = 2, 3, 6, 7), containing a four-membered heterometalla ring.Financial support from the MINECO of Spain (Projects CTQ2014-52799-P and CTQ2014-51912-REDC), the Diputación General de Aragón (E-35), FEDER, and the European Social Fund is acknowledged.Peer reviewe

LES Turbulence models. Relation with stabilized numerical methods

One of the aims of this text is to show some important results in LES modelling and to identify which are main mathematical problems for the development of a complete theory. A relevant aspect of LES theory, which we will consider in our work, is the close relationship between the mathematical properties of LES models and the numerical methods used for their implementation. In last years it is more and more common the idea in the scientific community, especially in the numerical community, that turbulence models and stabilization techniques play a very similar role. Methodologies used to simulate turbulent flows, RANS or LES approaches, are based on the same concept: unability to simulate a turbulent flow using a finite discretization in time and space. Turbulence models introduce additional information (impossible to be captured by the approximation technique used in the simulation) to obtain physically coherent solutions. On the other side, numerical methods used for the integration of partial differential equations (PDE) need to be modified in order to able to reproduce solutions that present very high localized gradients. These modifications, known as stabilization techniques, make possible to capture these sharp and localized changes of the solution. According with previous paragraphs, the following natural question appears: Is it possible to reinterpret stabilization methods as turbulence models? This question suggests a possible principle of duality between turbulence modelling and numerical stabilization. More than to share certain properties, actually, it is suggested that the numerical stabilization can be understood as turbulence. The opposite will occur if turbulence models are only necessary due to discretization limitations instead of a need for reproducing the physical behaviour of the flow. Finally: can turbulence models be understood as a component of a general stabilization method