PFEM application in fluid structure interaction problems

In the current paper the Particle Finite Element Method (PFEM), an innovative numerical method for solving a wide spectrum of problems involving the interaction of fluid and structures, is briefly presented. Many examples of the use of the PFEM with GiD support are shown. GiD framework provides a useful pre and post processor for the specific features of the method. Its advantages and shortcomings are pointed out in the present work.Peer ReviewedPostprint (published version

A new species of Arrhopalites (Collembola, Symphypleona, Arrhopalitidae) from a cave on the Central East Iberian Peninsula

A new species of Collembola, Arrhopalites miravetensis, sp. nov., is described, from a karstic cave in the “Desierto de las Palmas” Nature Park, Castellón, Spain. The new species can be distinguished from all other species in the genus by the combination of the following characters: 2+2 pigmented eyes, rod-like anal appendage with two, relatively long, basal projections, small teeth present in both mucro edges and visible only from posterior view, winged circumanal setae, and no spines on the head. The new species belongs to the A. pygmaeus-group s. str. This species could be a troglophile species as the most of Arrhopalites, although there are too troglobite species

Chlorinated solvents transport and natural attenuation modeling in groundwater

International audienceThe purpose of this study is to compare natural attenuation models to predict transport and fate of chlorinated solvents in saturated groundwater Systems. This work was realised within the framework of the research program TRANSPOL. This program was created in order to bring a better and common practice of the use of transport models concerning various pollutants the most encountered. Real case study, Real Case 3, concerns chlorinated solvents fate and transport in groundwater

An accurate nonlocal bonded discrete element method for nonlinear analysis of solids: application to concrete fracture tests

The final publication is available at Springer via http://dx.doi.org/10.1007/s40571-019-00278-5.We present a numerical procedure for elastic and nonlinear analysis (including fracture situations) of solid materials and structures using the discrete element method. It can be applied to strongly cohesive frictional materials such as concrete and rocks. The method consists on defining nonlocal constitutive equations at the contact interfaces between discrete particles using the information provided by the stress tensor over the neighbor particles. The method can be used with different yield surfaces, and in the paper, it is applied to the analysis of fracture of concrete samples. Good comparison with experimental results is obtained.Peer ReviewedPostprint (author's final draft

Design and validation of rockfall protection systems by numerical modeling with discrete elements

Rockfall protection systems are installed in order to preserve civil infrastructures against landslides and falling rocks. For the evaluation of these systems,one of the main problems is the difficulty to develop laboratory tests, since landslides and falling rocks are unpredictable events that involve the movement of large masses of material over several meters or evenkil-ometers. For this reason, the use of numerical methods, which allows reproducing full-scale situations without the need of laboratory devices or sliding materials, has become more popular. The study presented in this document shows theapplication of the Discrete Element Method (DEM) for the analysis of the behavior of one of the most popular rockfall protection systems, flexible metallic fences.Postprint (published version

Possibilities of the particle finite element method in computational mechanics

We present some developments in the formulation of the Particle Finite Element Method (PFEM) for analysis of complex coupled problems in fluid and solid mechanics accounting for fluid-structure interaction and coupled thermal effects. The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in both the fluid and the structure domains. Nodes are viewed as material points which can freely move and even separate from the main analysis domain representing, for instance, the effect of water drops. A mesh connects the nodes defining the discretized domain where the governing equations are solved as in the standard FEM. The necessary stabilization for dealing with the incompressibility of the fluid is introduced via the finite calculus (FIC) method. An incremental iterative scheme for the solution of the non linear transient coupled fluid-structure problem is described. Extensions of the PFEM to allow for frictional contact conditions at fluid-solid and solid-solid interfaces via mesh generation are described. A simple algorithm to treat erosion in the fluid bed is presented. Examples of application of the PFEM to solve a number of coupled problems such as the effect of large wave on structures, the large motions of floating and submerged bodies, bed erosion situations and melting and dripping of polymers under the effect of fire are given.Preprin

Lagrangian analysis of multiscale particulate flows with the particle finite element method

The final publication is available at Springer via http://dx.doi.org/10.1007/s40571-014-0012-9We present a Lagrangian numerical technique for the analysis of flows incorporating physical particles of different sizes. The numerical approach is based on the particle finite element method (PFEM) which blends concepts from particle-based techniques and the FEM. The basis of the Lagrangian formulation for particulate flows and the procedure for modelling the motion of small and large particles that are submerged in the fluid are described in detail. The numerical technique for analysis of this type of multiscale particulate flows using a stabilized mixed velocity-pressure formulation and the PFEM is also presented. Examples of application of the PFEM to several particulate flows problems are given.Peer ReviewedPostprint (published version

Reproductive fluids, used for the in vitro production of pig embryos, result in healthy offspring and avoid aberrant placental expression of PEG3 and LUM

Background: In vitro embryo production (IVP) and embryo transfer (ET) are two very common assisted reproductive technologies (ART) in human and cattle. However, in pig, the combination of either procedures, or even their use separately, is still considered suboptimal due to the low efficiency of IVP plus the difficulty of performing ET in the long and contorted uterus of the sow. In addition, the potential impact of these two ART on the health of the offspring is unknown. We investigated here if the use of a modified IVP system, with natural reproductive fluids (RF) as supplements to the culture media, combined with a minimally invasive surgery to perform ET, affects the output of the own IVP system as well as the reproductive performance of the mother and placental molecular traits. Results: The blastocyst rates obtained by both in vitro systems, conventional (C-IVP) and modified (RF-IVP), were similar. Pregnancy and farrowing rates were also similar. However, when compared to in vivo control (artificial insemination, AI), litter sizes of both IVP groups were lower, while placental efficiency was higher in AI than in RF-IVP. Gene expression studies revealed aberrant expression levels for PEG3 and LUM in placental tissue for C-IVP group when compared to AI, but not for RF-IVP group. Conclusions: The use of reproductive fluids as additives for the culture media in pig IVP does not improve reproductive performance of recipient mothers but could mitigate the impact of artificial procedures in the offspring.MINECO, FEDER, Fundación Senec

Advances in the DEM and coupled DEM and FEM techniques in non linear solid mechanics

Abstract In this chapter we present recent advances in the Discrete Element Method (DEM) and in the coupling of the DEM with the Finite Element Method (FEM) for solving a variety of problems in non linear solid mechanics involving damage, plasticity and multifracture situations.Preprin

Mycobacterium manresensis induces trained immunity in vitro

The COVID-19 pandemic posed a global health crisis, with new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants weakening vaccine-driven protection. Trained immunity could help tackle COVID-19 disease. Our objective was to analyze whether heat-killed Mycobacterium manresensis (hkMm), an environmental mycobacterium, induces trained immunity and confers protection against SARS-CoV-2 infection. To this end, THP-1 cells and primary monocytes were trained with hkMm. The increased secretion of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1β, and IL-10, metabolic activity, and changes in epigenetic marks suggested hkMm-induced trained immunity in vitro. Healthcare workers at risk of SARS-CoV-2 infection were enrolled into the MANRECOVID19 clinical trial (NCT04452773) and were administered Nyaditum resae (NR, containing hkMm) or placebo. No significant differences in monocyte inflammatory responses or the incidence of SARS-CoV-2 infection were found between the groups, although NR modified the profile of circulating immune cell populations. Our results show that M. manresensis induces trained immunity in vitro but not in vivo when orally administered as NR daily for 14 days. Biological sciences; Molecular biology; Immunology; Microbiolog