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Develops a computed laminography system for inspecting large or flat objects using x-rays. Necessity of object translation in the method; Basis for reconstruction of object cross sections; Use of a microfocus x-ray tube and line detector for object inspection with 50 micrometer slice resolution.

Abstract: Algebraic reconstruction methods are used widely for limited view tomography. They have been preferred with limited view and also with noisy data. Memory and compute intensive nature of these algorithms make it difficult to be used for higher resolution reconstruction. Present work encompasses a single view coded modified multiplicative algebraic reconstruction technique for circular and helical cone beam data collection geometries. The algorithm provides good results for (a) classical circular scan trajectory and (b) long object scanning performed with helical scan trajectory. Reconstruction results with real data indicate encouraging results for circular as well as helical scanning geometry. [Copyright &y& Elsevier]

Various studies have reported the changes in the mechanical properties and the modification in morphology of polyamide due to the absorption of water. However, the relation between the local water content and the alteration in the properties has not been consolidated in a coupled model yet. In the current work, a simulation model is proposed that can capture the diffusion of water as well as simulate the effect of the local moisture content on the stiffness of polyamide (PA6). To this end, a finite element model was developed by coupling of a nonlinear diffusion model and a viscoelastic material model. The Galerkin finite element method was used to formulate the weak form of the equations for the two physical processes. The coupled nonlinear equations were solved with the help of the Newton method. The diffusion process was studied experimentally with the help of gravimetric measurements. Relaxation tests were conducted on the polyamide specimens that were saturated under different moisture levels. Based on these experimental results, the dependency of the material parameters on the local moisture content was identified and an efficient and stable numerical simulation model has been developed. [ABSTRACT FROM AUTHOR]