Comparison of two linearization schemes for the nonlinear bending problem of a beam pinned at both ends

The nonlinear bending problem of a constant cross-section simply supported beam pinned at both ends and subject to a uniformly distributed load qðxÞ is analyzed in detail. The numerical integration of the two-point boundary value problem (BVP) derived for the nonlinear Timoshenko beam is tackled through two different linearization schemes, the multi-step transversal linearization (MTrL) and the multi-step tangential linearization (MTnL), proposed by Viswanath and Roy (2007). The fundamentals of these linearization techniques are to replace the nonlinear part of the governing ODEs through a set of conditionally linearized ODE systems at the nodal grid points along the neutral axis, ensuring the intersection between the solution manifolds (transversally in the MTrL and tangentially in the MTnL). In this paper, the solution values are determined at grid points by means of a centered finite differences method with multipoint linear constraints (Keller, 1969), and a simple iterative strategy. The analytical solution for this kind of bending problem, including the extensional effects, can be worked out by integration of the governing two-point BVP equations (Monleón et al., 2008). Finally, the comparison of analytical and numerical results shows the better ability of MTnL with the proposed iterative strategy to reproduce the theoretical behavior of the beam for each load step, because the restraint of equating derivatives in MTnL leads to further closeness between solution paths of the governing ODEs and the linearized ones, in comparison with MTrL. This result is opposed to the conclusion reached in Viswanath and Roy (2007), where the relative errors produced by MTrL are said to be smaller than the MTnL ones for the simply supported beam and the tip-loaded cantilever beam problems. 2009 Elsevier Ltd. All rights reserved.Merli Gisbert, R.; Lazaro, C.; Monleón Cremades, S.; Domingo Cabo, A. (2010). Comparison of two linearization schemes for the nonlinear bending problem of a beam pinned at both ends. International Journal of Solids and Structures. 47(6):865-874. doi:10.1016/j.ijsolstr.2009.12.001S86587447

Lipid-Lowering Therapy is Related to Inflammatory Markers and 3-Year Mortality in Patients With Critical Limb Ischemia.

To evaluate relationships between lipid-lowering therapy, inflammation, and 3-year mortality in critical limb ischemia (CLI), 259 consecutive CLI patients underwent evaluation of medication, tumor necrosis factor-alpha, interleukin-6 (IL6), neopterin, high-sensitivity C-reactive protein (hs-CRP), 8-epi-PGF2alpha, and endothelin-1. Mortality was assessed after 3 years. Sixty-one patients (24%) were on lipid-lowering therapy and 59 patients (97%) on statins. Patients on lipid-lowering therapy were younger and showed lower low-density lipoprotein cholesterol, hs-CRP, and IL-6 levels than patients without therapy. Three-year survival was higher among patients on lipid-lowering therapy. In logistic regression, the effect of lipid-lowering therapy on 3year survival was significant with inflammatory markers entered into the model one by one but disappeared when all inflammatory markers were entered into the model together. In conclusion, hs-CRP and IL-6 levels were lower and 3-year survival was higher in CLI patients on lipid-lowering therapy

Decolorization of textile dyes by Bjerkandera sp. BOL 13 using waste biomass as carbon source

BACKGROUND: Phanerochaete chrysosporium, Trametes versicolor and Bjerkandera sp BOL13 were compared for decolorization of azo dyes supplied individually or as a mixture. The dye decolorization was also evaluated during continuous treatment under non-sterile conditions using a lignocellulosic growth substrate. RESULTS: Bjerkandera sp BOL13 showed the highest dye decolorization potential. This fungus was also found to support high decolorization of Remazol Red RR at an initial pH of 4-6 and when using straw as co-substrate. The fungus was evaluated for Remazol Red RR decolorization in a continuously fed packed-bed bioreactor operated under non-sterile conditions with 3 days of hydraulic retention time. When glucose was supplied as growth-substrate, decolorization efficiencies of 65-90% were maintained for 12 days in a bioreactor packed with wooden material. The decolorization efficiency was lower when glucose was not fed to the fungus or when a plastic material was used as packing. Higher manganese peroxidase and laccase activities were also recorded when the wood packing was used. Contamination caused a drop in decolorization efficiency after 17-19 days operation. CONCLUSIONS: The potential of Bjerkandera sp BOL13 for decolorization of azo dyes under non-sterile conditions using lignocellulosic growth substrates was demonstrated. Research is needed to reduce contamination under non-sterile conditions