Serological survey concerning the IBR, CHV2, BVD, PI3, BRS and rinderpest viruses in small ruminants in Zaire

More than 400 small ruminant sera from Zaire were screened for antibodies to IBR, CHV2, BVD, bovine and ovine PI3, BRS and rinderpest viruses. Sera from local animals were negative for BVD, PI3 and rinderpest viruses: 8% of sera were positive for IBR virus, all with higher titers to CHV2; 31% of sera were positive to BRS virus

Serological survey on the prevalence of bovine type-4 herpesvirus infection in cattle in the Accra plains of Ghana

Sera from cattle of the Accra Plains in Ghana were screened for bovine type-4 herpesvirus (BHV-4) antibodies by an indirect immunofluorescence test. Among the 176 screened serums, 14% were found positive at a 1/100 dilution. Further studies are necessary for a better understanding of the relationships between BHV-4 or some other agents and necrotic vaginitis associated with poor fertility observed in cattle in this area

An augmented Lagrangian optimization method for inflatable structures analysis problems

This paper describes the development of an augmented Lagrangian optimization method for the numerical simulation of the inflation process in the design of inflated space structures. Although the Newton-Raphson scheme has proved to be efficient for solving many non linear problems, it can lead to lacks of convergence when it is applied to the simulation of the inflation process. As a result, it is recommended in the literature to use an optimization algorithm in order to find the minimum energy configuration that satisfies the equilibrium equations characterizing the final shape of the inflated structure subject to an internal pressure. Besides, given that some degrees of freedom may be linked, the optimum may be constrained. The paper presents the formulation and the augmented Lagrangian method (ALM) developed in SAMCEF Mecano for inflatable structures analysis problems. The related quasiunconstrained optimization problem is solved with a non linear conjugate gradients method. The Wolfe conditions are used in conjunction with a cubic interpolation for the line search. Equality constraints are considered and can be easily treated by the ALM formulation. Numerical applications present simulations of unconstrained as well as constrained inflation processes (i.e. where some nodes' motion is ruled by a rigid body element restriction, and/or problems including contact conditions). 2. Keywords: Augmented Lagrangian Method, Conjugate Gradients Method, inflatable structures, contact 3

Shape Control of Thin Shell Reflectors for Future Space Telescopes

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Technical properties of tachymeters Leica Geosystems

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Morphing of Multi-Layer Thin Shell Reflectors for Future Space Telescopes

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Multi-layer Adaptive Thin Shells for Future Space Telescopes

This paper examines the morphing capability of doubly curved elastic shells with various layers of active materials with strain actuation capability. The equivalent piezoelectric loads of an orthotropic multi-layer shell is established and it is demonstrated that a set of four active layers offer independent control of the in-plane forces and bending moments, which guarantees optimum morphing with arbitrary profile. This is illustrated by a numerical example which compares a unimorph configuration (single layer of active material) with a twin-bimorph (two pairs of symmetrical layers of active material with orthotropic properties). Numerical simulations indicate that the optical (Zernike) modes with shapes where the curvatures in orthogonal directions have opposite signs (e.g. astigmatism, trefoil, tetrafoil) are fairly easy to control with both configurations and that substantial amplitudes may be achieved. However, the optical modes with shapes where the curvatures in orthogonal directions have the same sign (e.g. defocus, coma, spherical aberration) are difficult to control with the unimorph configuration, and they lead to the appearance of slope discontinuities at the interface between the independent electrodes. As expected, a much better morphing is achieved with a twin-bimorph configuration. © 2012 IOP Publishing Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Swaged bolts: modelling of the installation process and numerical analysis of the mechanical behaviour

Swaged bolts are an alternative to high strength bolts in steel structures. To clarify the steps of the installation process, numerical modelling has been carried out. The relevant phenomena are described and evaluated. This numerical calculation accounts for large displacements, large strains, mechanical plasticity and friction contact between the components of swaged bolts. The non-linear finite element code ‘‘Lagamine’’ designed for the simulation of metal forming processes has been used to provide the stress distributions in the components