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    Physiological Parameters Relevant to Dissolution Testing - Hydrodynamic Considerations (rev. and suppl. version)
    (Tübingen : Universitätsbibliothek Tübingen, 2023) Diebold, Steffen M.
    The first two sections of the monograph present an introduction into basic hydrodynamics relevant to in vitro dissolution testing including V. G. Levichs convective diffusion theory and the authors combination model. This part is followed by hydrodynamic considerations of in vivo dissolution including hydrodynamic problems inherent to in vivo bioavailability of solid oral dosage forms. Hydrodynamics in the upper GI tract contribute to in vivo dissolution. Our ability to forecast dissolution of poorly soluble drugs in vitro depends on our knowledge of and ability to control hydrodynamics as well as other factors influencing dissolution. Provided suitable conditions (apparatus, hydrodynamics, media) are chosen for the dissolution test, it seems possible to predict dissolution limitations to the oral absorption of drugs and to reflect variations in hydrodynamic conditions in the upper GI tract. The fluid volume available for dissolution in the gut lumen, the contact time of the dissolved compound with the absorptive sites and the particle size have been identified as the main hydrodynamic determinants for the absorption of poorly soluble drugs in vivo. The influence of these factors is usually more pronounced than that of the motility pattern or the gastrointestinal flow rates per se.
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    Composite forming simulation for non-crimp fabrics based on generalized continuum approaches – AMECOMP : Abschlussbericht / Final project report (DFG 431354059 / ANR-19-CE06-0031)
    (Hannover : Technische Informationsbibliothek, 2024-05) Schäfer, Bastian; Kärger, Luise; Naouar, Naim; Zheng, Ruochen; Schäfer, Bastian; Kärger, Luise; Naouar, Naim; Zheng, Ruochen; Boisse, Philippe; Colmars, Julien; Platzer, Auriane
    Continuously carbon fiber reinforced composites are increasingly used for structural applications in various fields of engineering due to their excellent weight-specific mechanical properties. Non-crimp-fabrics (NCF) provide the highest lightweight potential as reinforcement for the composite due to their straight fibers, compared to woven fabrics with undulated fibers. NCFs are made of one (UD-NCF), two (Biax-NCF) or more directions of fibers linked together with a polymer stitching in specific patterns. The deformation behavior of NCFs is challenging due to the interaction between the fibers and the stitching, which also results in a higher susceptibility to forming effects such as roving slippage, fiber waviness and gapping compared to woven fabrics. The aim of the AMECOMP project was to improve the understanding of the forming behavior of NCFs and to develop suitable simulation models to broaden the range of potential applications. Mesoscopic models that accurately describe the architecture of the NCF were developed for virtual material characterization and detailed analysis of forming defects in critical areas. Macroscopic models that describe the relevant deformation mechanisms of NCF in a homogenized way were developed for efficient analysis of large components and multi-layer stacks.