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Isogeometric shape optimisation has been studied for over a decade. The present contribution focuses on applying this approach to aircraft engine blades design by integrating geometric description, structural analysis and shape optimisation in a single industrial framework. Starting with stacked cross-sections of the blade geometry as an input, we construct a B-spline analysis-suitable volumetric model of the blade, ensuring its geometric accuracy and parametrisation regularity. Using the multi-level approach inherent to Isogeometric Analysis, we perform structural shape optimisation with the same geometric representation of the blades in the analysis and optimisation; the final optimised model being directly CAD compatible. Several self-adjoint problems are addressed using gradient-based optimisation with full analytical sensitivities that are obtained in a compact form thanks to the isogeometric framework. Examples of interest are solved using suitable industrial loading cases and objective functions. The results demonstrate the efficiency of the method and its relevance for industrial aircraft engine blades design and optimisation. [ABSTRACT FROM AUTHOR]

We propose a convenient methodology for the modeling and analysis of aircraft compressor blades. To meet this goal, IsoGeometric Analysis is put to good use, as it allows for an exact representation of the geometry, especially for the analysis. This work aims at developing numerical tools to handle mechanical analysis, and later on shape optimisation, of 3D aircraft engine compressor blades using IGA. More precisely, our final goal is to carry out shape optimisation of one precise patch belonging to a complex multipatch structure, while having other patches to follow automatically the geometric changes. To meet this goal, work on geometric and modeling aspects are needed, which is the objective of this paper. Using the proposed techniques to perform gradient-based shape optimisation constitutes a work in itself and is therefore not presented here, but will be detailed in a follow-up paper. In our case, the complete blade assembly is represented using several volumetric patches: the airfoil, the platform, the tenon and the fillet. In order to ensure the geometric compatibility between the different patches, we propose an embedded solid element formulation. A mortar method is implemented in order to guarantee the coupling between the various parts of the assembly. The results show a great potential for the proposed approach for blades design, while concurrently offering broad perspectives in terms of applications. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with a Finite Element (FE) behavior analysis of a shape memory alloy actuator for a micropump. It is composed of two membranes of NiTi shape memory alloy (SMA) in a martensitic state at room temperature. They have an initial flat shape and are bonded together with an intermediate spacer. The thermal loading allows the actuator to move up and down in the membrane normal direction. A detailed analysis of sensibility to material and geometric parameters of the SMA actuator is undertaken by FE method. The actuation capability and reliability are studied in order to lead to optimal parameters set providing a higher stroke (deflection) with a low heating temperature. The shape memory effect exhibited by these membranes is simulated by means of the phenomenological constitutive law based on Chemisky–Duval model , and implemented in the Abaqus® FE code. The obtained numerical results were detailed proving the ability of the proposed modeling to reproduce the actuator behavior under thermal loading. This analysis showed that it is possible to provide a large stroke for a minimal geometry of the actuator. [Copyright &y& Elsevier]

Objective. We attempted to evaluate endothelial dysfunction and the role of AECAs in systemic lupus (SL) with low disease activity. We quantified endothelial microparticles (EMps) and attempted to find the best flow cytometry method for that purpose. [ABSTRACT FROM PUBLISHER]

Prurigo nodularis is a pruritic dermatosis of unknown origin. Human T-cell lymphotropic virus type I (HTLV- 1) causes adult T-cell leukaemia/lymphoma. HTLV-1 is not considered to be a cause of prurigo nodularis. A 52-year-old black man, from the French West Indies, who had had prurigo nodularis for 12 years, presented with a distinct micropapular eruption with the typical pathological picture of epidermotropic T-cell lymphoma. Based on HTLV-1-positive serology and monoclonal integration of HTLV-1 we diagnosed smouldering adult T-cell leukaemia/lymphoma. Re-examinination of previous skin biopsies revealed that the disease had been evolving for 12 years. Treatment with n-interferon, 3 × 106 units three times a week, associated with zidovudine, I g daily, resulted in complete remission within 4 months. When investigating a prurigo nodularis, we therefore recommend: (1) performing HTLV-1 serology if the patient comes' from an endemic area; (ii) if positive, performing CD25 staining and looking for a HTLV-1 clonal integration; and (iii) if positive, using a treatment targeting HTLV-1. [ABSTRACT FROM AUTHOR]

A nonconventional application of worm gears exploits the irreversibility of these power transmission devices in order to realize fast emergency braking. This application can be used to secure lifting devices. A limiting factor in the design of these instantaneous braking systems is the residual deformations of the worm/wheel contacting teeth, due to the impact between them at each emergency stop. The prediction of these residual displacements requires solving of an elastic–plastic, multi-scale and multi-contact problem. Original numerical tools were developed in this study to solve the problem at global and local scales. The method has been validated by comparing the obtained results with 3D measurements on new and deformed worm/wheel pairs. In order to predict the issue of the worm gear after an impact, a criterion based on kinematic errors is proposed. Applying this criterion gives the maximal admissible torque for the braking system to be operational after the impact. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented about a study concerning aprepitant as an antipruritic agent.

This paper discusses the tractive rolling contact between dissimilar and multi-layered bodies. Drawn from the Kalker's theory on the three dimensional rolling contact, the rolling contact in presence of tangential forces and a spinning moment is formulated. In the present paper, the focus is put on the tangential component of the problem. Then, the variational formulation of the contact problem is solved using a Conjugate Gradient Method (CGM) coupled with Fast Fourier Transform (FFT) algorithms for acceleration. The proposed solver allows to solve the tractive rolling contact problem in both transient and steady-state regimes. The multi-layered aspect of the bodies in contact is taken into account through the influence coefficients used for the calculation of the elastic displacements and stresses. Further, a validation of the model is performed by comparison with models from the literature. The transition from the Cattaneo–Mindlin shift to the steady-state regime is analysed, with Kalker's solution in the validation section for elastically similar bodies, and further in a parametric study for elastically dissimilar bodies. Moreover, the parametric study allows to highlight the effects of various combinations of the tangential loading input on the stick and the slip zones within the contact zone. Finally, the three dimensional stresses are analysed in a multi-layered body. • Tractive contact in presence of tangential forces and spinning moment is formulated. • The problem is solved both in transient and steady-state regimes.. • A parametric study allows to highlight the effect of various combinations of loading. • Effect on stick and the slip zones within the contact area is investigated in detail. • Finally, the three dimensional stresses are analysed in a multi-layered body. [ABSTRACT FROM AUTHOR]

Non-thermal plasmas are gaseous mixtures of molecules, radicals, and excited species with a small proportion of ions and energetic electrons. Non-thermal plasmas can be generated with any high electro-magnetic field. We studied here the pathological effects, and in particular cell death, induced by nanosecond-pulsed high voltage generated plasmas homogeneously applied on cell cultures and nude mouse skin. In vitro, Jurkat cells and HMEC exhibited apoptosis and necrosis, in dose-dependent manner. In vivo, on nude mouse skin, cell death occurred for doses above 113 J/cm2 for the epidermis, 281 J/cm2 for the dermis, and 394 J/cm2 for the hypodermis. Using electron microscopy, we characterized apoptosis for low doses and necrosis for high doses. We demonstrated that these effects were not related to thermal, photonic or pH variations, and were due to the production of free radicals. The ability of cold plasmas to generate apoptosis on cells in suspension and, without any sensitizer, on precise skin areas, opens new fields of application in dermatology for extracorporeal blood cell treatment and the eradication of superficial skin lesions. [ABSTRACT FROM AUTHOR]

This article explores the applicability of numerical homogenization techniques for analyzing transport properties in real foam samples, mostly open-cell, to understand long-wavelength acoustics of rigid-frame air-saturated porous media on the basis of microstructural parameters. Experimental characterization of porosity and permeability of real foam samples are used to provide the scaling of a polyhedral unit-cell. The Stokes, Laplace, and diffusion-controlled reaction equations are numerically solved in such media by a finite element method in three-dimensions; an estimation of the materials' transport parameters is derived from these solution fields. The frequency-dependent visco-inertial and thermal response functions governing the long-wavelength acoustic wave propagation in rigid-frame porous materials are then determined from generic approximate but robust models and compared to standing wave tube measurements. With no adjustable constant, the predicted quantities were found to be in acceptable agreement with multi-scale experimental data and further analyzed in light of scanning electron micrograph observations and critical path considerations. [ABSTRACT FROM AUTHOR]

In this paper, IsoGeometric Analysis is applied to a transient nonlinear heat conduction problem using a predictor-corrector scheme. To obtain a better approximation of the solution, we propose the k-refinement method coupled to a Matrix-Free Weighted Quadrature approach which speeds up matrix-vector operations and also reduces memory consumption. The main goal of this work is to introduce a preconditioning strategy to improve the convergence rate of the iterative solver. This method is based on Fast Diagonalization technique which exploits the tensor structure of basis functions. We show that our preconditioner is inexpensive, easy to code and as effective as other more sophisticated methods. It is also robust with respect to polynomial degree, mesh size and time-integration scheme parameters. Numerical experiments for different geometries and materials are presented, which support our theoretical results. • A nonlinear transient heat transfer equation is solved using IsoGeometric Analysis. • Matrix-Free and Weighted Quadrature significantly reduce the CPU time and memory. • A good preconditioner can increase the iterative solver convergence rate. • The proposed one is robust, easy to code, inexpensive, suited to transient problem. [ABSTRACT FROM AUTHOR]

In this paper, the contact problem between a rigid indenter and a viscoelastic half space containing either isotropic or anisotropic elastic inhomogeneities is solved. The model presented here is 3D and based on semi-analytical methods. To take into account the viscoelastic properties of the matrix, contact and subsurface problem equations are discretized in the spatial and temporal dimensions. A conjugate gradient method and the fast Fourier transform are used to solve the normal problem, contact pressure, subsurface problem and real contact area simultaneously. The Eshelby's formalism is applied at each step of the temporal discretization to account for the effect of the inhomogeneity on pressure distribution and subsurface stresses. This method can be seen as an enrichment technique where the enrichment fields from heterogeneous solutions are superimposed to the homogeneous viscoelastic problem solution. Note that both problems are fully coupled. The model is validated by comparison with a Finite Element Model. A parametric analysis of the effect of elastic properties and geometrical features of the inhomogeneity is proposed. The model allows to obtain the contact pressure distribution disturbed by the presence of inhomogeneities as well as subsurface and matrix/inhomogeneity interface stresses at every step of the temporal discretization. [ABSTRACT FROM AUTHOR]