Effects of finite strains in fully coupled 3D geomechanical simulations

Numerical modeling of geomechanical phenomena and geo-engineering problems often involves complex issues related to several variables and corresponding coupling effects. Under certain circumstances, both soil and rock may experience a nonlinear material response caused by, for example, plastic, viscous, or damage behavior or even a nonlinear geometric response due to large deformations or displacements of the solid. Furthermore, the presence of one or more fluids (water, oil, gas, etc.) within the skeleton must be taken into account when evaluating the interaction between the different phases of the continuum body. A multiphase three-dimensional (3D) coupled model of finite strains, suitable for dealing with solid-displacement and fluid-diffusion problems, is described for assumed elastoplastic behavior of the solid phase. Particularly, a 3D mixed finite element was implemented to fulfill stability requirements of the adopted formulation, and a permeability tensor dependent on deformation is introduced. A consolidation scenario induced by silo filling was investigated, and the effects of the adoption of finite strains are discusse

Cardiopulmonary bypass-induced coagulopathy in paediatric patients: the Role of Platelets in postoperative bleeding. A preliminary study

INTRODUCTION: Paediatric patients are particularly prone to cardiopulmonary bypass (CPB)-induced coagulopathy mainly due to haemodilution, consumption of coagulation factors and hypothermia. The aim of the present study was to examine the possible role of platelet count and function as it relates to the bleeding risk after CPB in the paediatric population.MATERIALS AND METHODS: All consecutive patients (age 75th percentile were bleeders (cases). Controls were non-bleeders.RESULTS: A total of 31 patients were enrolled [median age 17 (4-57) months]. A significant postoperative reduction in platelet count (p 262500 x109 /L, a DeltaADP-test >29 U, a DeltaTRAP-test >44 U and a DeltaASPI-test >26 U showed to be predictive of major postoperative bleeding.CONCLUSIONS: Postoperative bleeding in children undergoing cardiac surgery with CPB was linked to younger age, longer CPB duration and significant postoperative reduction in platelet count and function. Larger studies are needed to confirm our results and define strategies to reduce postoperative bleeding in these patients

Energy calibration and resolution of the CMS electromagnetic calorimeter in pp collisions at s\sqrt{s} = 7 TeV

The energy calibration and resolution of the electromagnetic calorimeter (ECAL) of the CMS detector have been determined using proton-proton collision data from LHC operation in 2010 and 2011 at a centre-of-mass energy of sqrt(s)=7 TeV with integrated luminosities of about 5 inverse femtobarns. Crucial aspects of detector operation, such as the environmental stability, alignment, and synchronization, are presented. The in-situ calibration procedures are discussed in detail and include the maintenance of the calibration in the challenging radiation environment inside the CMS detector. The energy resolution for electrons from Z-boson decays is better than 2% in the central region of the ECAL barrel (for pseudorapidity abs(eta)<0.8) and is 2-5% elsewhere. The derived energy resolution for photons from 125 GeV Higgs boson decays varies across the barrel from 1.1% to 2.6% and from 2.2% to 5% in the entraps. The calibration of the absolute energy is determined from Z to e+e- decays to a precision of 0.4% in the barrel and 0.8% in the endcaps