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Solid Structure (solid + structure)
Selected AbstractsA Coupled 3D Discrete-Finite Element Method for the Simulation of Granular Materials and Their Interaction with Solid StructuresPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2008Christian Wellmann No abstract is available for this article. [source] Solid-State Adducts between C60 and DecamethylferroceneEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2003Aldo Arrais Abstract Co-deposition from concentrated solutions of C60 and Fe[C5(CH3)5]2 affords two solid products in different yields. The major product 1, in the form of regular shaped crystals, has been investigated by X-ray diffraction, 13C CPMAS NMR and vibrational spectroscopy, which showed it to be a co-crystalline adduct of C60 and Fe[C5(CH3)5]2 with no significant electron charge transfer between the two building blocks. The minor product 2, in the form of an amorphous powder, has been investigated by vibrational techniques. Both IR and Raman spectra are consistent with a solid structure in which electron transfer between the two units appears to be possible. ((© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Predictive index for carcinoma of thyroid nodules and its integration with fine-needle aspiration cytology,HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 7 2009Bekir Kuru MD Abstract Background The objective of this study was to select patients for resection of thyroid malignity among patients with thyroid nodules by integration of predictive indices with fine-needle aspiration cytology (FNAC). Methods Characteristics of 571 euthyroid patients with thyroid nodules who underwent surgery in our institution were prospectively recorded. Predictive factors for malignancy were identified and categorized as predictive indices that were integrated with FNAC to select patients for surgery. Results Eighty-three (14.5%) of the 571 patients had thyroid carcinoma. Size ,4 cm, age ,65, cervical lymph nodes, solid structure, hypoechogenicity, microcalcification, and elevated serum thyroglobulin levels were independent predictive factors associated with thyroid malignancy. Sensitivity, specificity, and accuracy of FNAC were 88%, 80%, and 81%, respectively, and were 100% for index 3. Conclusions Patients with malignant and suspicious FNAC findings and, among patients with follicular neoplasm and nondiagnostic FNAC findings, those with ,2 risk factors should undergo surgery. © 2009 Wiley Periodicals, Inc. Head Neck, 2009 [source] FEM simulation of turbulent flow in a turbine blade passage with dynamical fluid,structure interactionINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2009Lixiang Zhang Abstract Results are described from a combined mathematical modeling and numerical iteration schemes of flow and vibration. We consider the coupling numerical simulations of both turbulent flow and structure vibration induced by flow. The methodology used is based on the stabilized finite element formulations with time integration. A fully coupled model of flow and flow-induced structure vibration was established using a hydride generalized variational principle of fluid and solid dynamics. The spatial discretization of this coupling model is based on the finite element interpolating formulations for the fluid and solid structure, while the different time integration schemes are respectively used for fluid and solid structure to obtain a stabilized algorithm. For fluid and solid dynamics, Hughes' predictor multi-corrector algorithm and the Newmark method are monolithically used to realize a monolithic solution of the fully coupled model. The numerical convergence is ensured for small deformation vibrating problems of the structure by using different time steps for fluid and solid, respectively. The established model and the associated numerical methodology developed in the paper were then applied to simulate two different flows. The first one is the lid-driven square cavity flow with different Reynolds numbers of 1000, 400 and 100 and the second is the turbulent flows in a 3-D turbine blade passage with dynamical fluid,structure interaction. Good agreement between numerical simulations and measurements of pressure and vibration acceleration indicates that the finite element method formulations developed in this paper are appropriate to deal with the flow under investigation. Copyright © 2009 John Wiley & Sons, Ltd. [source] A hybrid immersed boundary and material point method for simulating 3D fluid,structure interaction problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2008Anvar Gilmanov Abstract A numerical method is developed for solving the 3D, unsteady, incompressible Navier,Stokes equations in curvilinear coordinates containing immersed boundaries (IBs) of arbitrary geometrical complexity moving and deforming under forces acting on the body. Since simulations of flow in complex geometries with deformable surfaces require special treatment, the present approach combines a hybrid immersed boundary method (HIBM) for handling complex moving boundaries and a material point method (MPM) for resolving structural stresses and movement. This combined HIBM & MPM approach is presented as an effective approach for solving fluid,structure interaction (FSI) problems. In the HIBM, a curvilinear grid is defined and the variable values at grid points adjacent to a boundary are forced or interpolated to satisfy the boundary conditions. The MPM is used for solving the equations of solid structure and communicates with the fluid through appropriate interface-boundary conditions. The governing flow equations are discretized on a non-staggered grid layout using second-order accurate finite-difference formulas. The discrete equations are integrated in time via a second-order accurate dual time stepping, artificial compressibility scheme. Unstructured, triangular meshes are employed to discretize the complex surface of the IBs. The nodes of the surface mesh constitute a set of Lagrangian control points used for tracking the motion of the flexible body. The equations of the solid body are integrated in time via the MPM. At every instant in time, the influence of the body on the flow is accounted for by applying boundary conditions at stationary curvilinear grid nodes located in the exterior but in the immediate vicinity of the body by reconstructing the solution along the local normal to the body surface. The influence of the fluid on the body is defined through pressure and shear stresses acting on the surface of the body. The HIBM & MPM approach is validated for FSI problems by solving for a falling rigid and flexible sphere in a fluid-filled channel. The behavior of a capsule in a shear flow was also examined. Agreement with the published results is excellent. Copyright © 2007 John Wiley & Sons, Ltd. [source] Development of clinical dosage forms for a poorly water-soluble drug II: Formulation and characterization of a novel solid microemulsion preconcentrate system for oral delivery of a poorly water-soluble drugJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2009Ping Li Abstract The solution of a poorly water-soluble drug in a liquid lipid,surfactant mixture, which served as a microemulsion preconcentrate, was converted into a solid form by incorporating it in a solid polyethylene glycol (PEG) matrix. The solid microemulsion preconcentrates thus formed consisted of Capmul PG8 (propylene glycol monocaprylate) as oil, Cremophor EL (polyoxyl 35 castor oil) as surfactant, and hydrophilic polymer PEG 3350 as solid matrix. The drug (aqueous solubility: 0.17 µg/mL at pH 1,8 and 25°C) was dissolved in a melt of the mixture at 65,70°C and then the hot solution was filled into hard gelatin capsules; the liquid gradually solidified upon cooling below 55°C. The solid system was characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), confocal Raman microscopy (CRM), and the dispersion testing in water. It was confirmed that a solid microemulsion preconcentrate is a two-phase system, where clusters of crystalline PEG 3350 formed the solid structure (m.p. 55,60°C) and the liquid microemulsion preconcentrate dispersed in between PEG 3350 crystals as a separate phase. The drug remained dissolved in the liquid phase. In vitro release testing showed that the preconcentrate dispersed readily in water forming a microemulsion with the drug dissolved in the oil particles (<150 nm) and the presence of PEG 3350 did not interfere with the process of self-microemulsification. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:1750,1764, 2009 [source] Ring-opening polymerization of ,-caprolactone by a new yttrium complex: Y[2,2,-ethylidene-bis(4,6-di- tert -butylphenoxy)]2(ethylene glycol dimethyl ether)Na(ethylene glycol dimethyl ether)3POLYMER INTERNATIONAL, Issue 4 2010Guangming Wu Abstract The main aims of the work reported here were to synthesize and characterize a new 2,2,-ethylidene-bis(4,6-di- tert -butylphenol) (EDBPH2)-based bimetal yttrium complex, Y(EDBP)2(DME)Na(DME)3 (1c; where DME is ethylene glycol dimethyl ether), which was employed as an efficient initiator for the ring-opening polymerization of ,-caprolactone (,-CL). From single-crystal X-ray diffraction, the solid structure of this new bimetal initiator was well established. Experimental results show that 1c initiates the ring-opening polymerization of ,-CL to afford poly(,-CL) with a narrow molecular weight distribution (Mw/Mn = 1.09,1.36, 65 °C). Based on an in situ NMR study, a plausible coordination,insertion mechanism is then proposed. The bimetal complex 1c can be used as an initiator for the ring-opening polymerization of ,-CL with some living characteristics. A study of the mechanism reveals that DME displacement in 1c by ,-CL is involved in the initiation process and the propagation may proceed through three pathways by NaO insertion or YO insertion. Copyright © 2009 Society of Chemical Industry [source] A cohort study of thyroid cancer and other thyroid diseases after the Chornobyl accident,CANCER, Issue 11 2006Pathology analysis of thyroid cancer cases in Ukraine detected during the first screening (1998-2000) Abstract BACKGROUND. The Ukrainian American Cohort Study evaluated the risk of thyroid disorders in a group of individuals who were younger than age 18 years at the time of the Chornobyl (Chernobyl) accident. In this article, the authors describe the pathology of thyroid carcinomas detected in the first screening. METHODS. From 1998 to 2000, 13,243 individuals completed the first cycle of screening examinations. Eighty patients underwent surgery between 1998 and 2004. Intraoperative and postoperative pathologic studies were performed at the Institute of Endocrinology and Metabolism, Kyiv. RESULTS. Pathologic analysis revealed 45 thyroid carcinomas, including 43 papillary thyroid carcinomas (PTCs) (95.6%) and 2 follicular thyroid carcinomas (FTCs) (4.4%). TNM classification (5th edition) of the PTCs included 8 T1 tumors (18.6%), 16 T2 tumors (37.2%), and 19 T4 tumors (44.2%). Fifteen PTCs (34.9%) were N1a,N1b, and 3 PTCs (7.0%) were M1. Among the PTCs, 8 exhibited the classical papillary histologic pattern (18.6%), 14 exhibited a follicular histologic pattern (32.6%), 5 exhibited a solid histologic pattern (11.6%), and 16 exhibited a mixed histologic pattern (37.2%). Both FTCs had a microfollicular-solid structure. Eleven of 20 cohort members who underwent surgery before the first screening had PTCs. Regional metastases (63.6%) and distant metastases (18.2%) were more common in this group. CONCLUSIONS. Multifocal growth, lymphatic and blood vessel invasion, extrathyroid spread, and regional and distant metastases were more frequent in less differentiated PTCs (>30% solid structure). Small carcinomas (,10 mm) comprised 23.3% of PTCs, and most of those (8 of 10 small carcinomas; 80%) were of the papillary-follicular subtype and therefore were more differentiated. The solid subtype of PTC was associated with shorter latency, especially in individuals who were diagnosed before the first screening. The histology of post-Chornobyl cancers is changing with time. Cancer 2006. Published 2006 by the American Cancer Society. [source] Layer-by-Layer Interference Lithography of Three-dimensional Microstructures in SU-8,ADVANCED ENGINEERING MATERIALS, Issue 5 2009Andrés F. Lasagni We report on rapid fabrication of two-, two and a half-, and 3D planar periodic structures using layer-by-layer deposition and interference patterning of SU-8 photoresist. Complex structures with non-periodic vertical symmetry were fabricated controlling the cure depth by addition of a UV absorber. The fabrication method reported here can be applied for the high-volume manufacturing of solid structures for microelectromechanical systems and microfluidic devices. [source] Volume-dependent pressure loading and its influence on the stability of structuresINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 2 2003T. Rumpel Abstract Deformation-dependent pressure loading on solid structures is created by the interaction of gas with the deformable surface of a structure. Such fairly simple load models are valid for static and quasi-static analyses and they are a very efficient tool to represent the influence of gas on the behaviour of structures. Completing previous studies on the deformation dependence of the loading with the assumption of infinite gas volumes, the current contribution is focusing on the influence of modifications of the size and shape of a finite volume containing the gas in particular on the stability of structures. The linearization of the corresponding virtual work expression necessary for a Newton-type solution leads to additional terms for the volume dependence. Investigating these terms the conservativeness of the problem can be proven by the symmetry of the linearized form. The discretization with finite elements leads to standard stiffness matrix forms plus the so-called load stiffness matrices and a rank-one update for each enclosed volume part, if the loaded surface segments are identical with element surfaces. Some numerical examples show first the effectiveness of the approach and the necessity to take the corresponding terms in the variational expression and in the following linearization into account, and second the particular influence of this term on the stability of structures is shown with some specific examples. Copyright © 2002 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||