1,720,993 research outputs found
C0 plate element for delamination damage analysis, based on a zig-zag model and strain energy updating
No full textIn this paper, a C0 eight-node plate element for analysis of global/local effects in sandwich and composite laminates is developed,based on a piecewise cubic zig-zag model. Characteristic feature,it is developed upon the kinematics and nodal degrees of freedom of a first-order,sh ear deformation parent plate element wherein strain energy is updated to incorporate the energy contributions brought by the zig-zag model. This allows to overcome the C1 continuity requirement resulting from enforcement of the transverse shear stress continuity at the interfaces. The element is implemented in a finite element code for damage simulation and used for investigating low velocity impact-induced damage in laminated composite panels with I and O stiffeners. The impact load is computed by the Hertz's contact law,where the dynamic equations are integrated by the Newmark's algorithm. Local damage extent and position across the thickness are predicted using several classical semi-empirical strength-based criteria,whi le degradation is simulated by reducing the stiffness of damaged plies. The damage extent and thickness position by present finite element simulation appears rather accurate when confronted with ultrasonic inspection and cost effective
Finite element for analysis of impact induced delamination
No full textNota Scientifica 220 DIASP-Politecnico di Torin
The Role of H3K4 Trimethylation in CpG Islands Hypermethylation in Cancer
No full textCpG methylation in transposons, exons, introns and intergenic regions is important for long-term silencing, silencing of parasitic sequences and alternative promoters, regulating imprinted gene expression and determining X chromosome inactivation. Promoter CpG islands, although rich in CpG dinucleotides, are unmethylated and remain so during all phases of mammalian embryogenesis and development, except in specific cases. The biological mechanisms that contribute to the maintenance of the unmethylated state of CpG islands remain elusive, but the modification of established DNA methylation patterns is a common feature in all types of tumors and is considered as an event that intrinsically, or in association with genetic lesions, feeds carcinogenesis. In this review, we focus on the latest results describing the role that the levels of H3K4 trimethylation may have in determining the aberrant hypermethylation of CpG islands in tumors
Low velocity impact induced delamination on composite stiffened panels: fem simulation and c-scan detection
No full textNota Scientifica 211 DIASP-Politecnic
Effects of thermal stresses on composite stiffened panels with impact induced delamination
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Inhibition of poly(ADP-ribosyl)ation introduces an anomalous methylation pattern in trasfected foreign DNA
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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