Rectangular shell elements based on the absolute nodal coordinate formulation

This thesis concerns the development of tools that are useful for designing machine systems and components in an virtual environment using flexible multibody dynamics. Initially, flexible multibody dynamics is briefly reviewed to explain available formalisms and possible applications of this method. Subsequently, attention is turned towards the analysis of structuresthat undergo large deformations and rotations using shell finite elements based on the absolute nodal coordinate formulation, ANCF. This topic is the focus for the remainder of the thesis. The thesis is divided into three main parts. The first part acts as a general introduction to ANCF based shell finite elements and sums up available elements found in the research literature. In the end, a new ANCF element developed during this PhD project is presented which gives enhanced modeling capabilities of problems including e.g. moving boundary conditions.The second part concerns the performance and behavior of a certain class of ANCF shell elements that are developed for analysis of thin shell structures. This includes discussions on differences concerning their kinematic descriptions and disclosure of certain issues regarding their performance. Those being sensitivity to irregular mesh, poor representation of curved structuresand load dependent convergence when analyzing curved structures.The final part concerns the development of a new versatile ANCF shell element. This element is distinguished by being able to describe both thin and thick curved structures. This part contains a thorough derivation of its kinematics and stiffness description, as well as numerical examples to demonstrate its performance. However, this part of the study is not yet complete. Finally, the findings of this PhD project are summed up in a conclusion and possibilities for further studies and perspectives are outline

Die Erforschung der Apostelgeschichte : Linien und Tendenzen

nicht vorhanden

Large Displacement Analysis of Shell Structures using the Absolute Nodal Coordinate Formulation

This report will review and discuss thin rectangular ANCF shell elements. First, a thorough review of the kinematic descriptions used in the current thin rectangular ANCF shells is given. This review will also contain a derivation of the equations of motion. Subsequently, a novel ANCF shell finite element with dynamic mesh properties is reviewed. This element is characterized by being able to change element size during transient simulation. The following chapter contains a preliminary study of the kinematics and numerical performance of thin rectangular ANCF shell elements when used in a curved and distorted mesh. A more general comparison of current element formulations is also performed. The results from the ANCF elements are compared to solutions obtained using a traditional commercial finite element code. At the end, the content of this report is summed up in a conclusion, and the outline of future work is presented

Use of chemically enhanced primary treatment in Puerto Rico

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.Includes bibliographical references (leaves 64-65).by Adrianne Hyldahl and Elisha Hopson.M.Eng

Pericyte NF-κB Activation Enhances Endothelial Cell Proliferation and Proangiogenic Cytokine Secretion

Pericytes are skeletal muscle resident, multipotent stem cells that are localized to capillaries. They respond to damage through activation of nuclear-factor kappa-B (NF-κB), a transcription factor that regulates many cellular processes including inflammation. Research has shown that pericyte NF-κB activation positively affects myoblast proliferation. It is unknown how pericyte NF-κB affects signaling and proliferation of endothelial cells, an important component of muscle tissue microcirculation. PURPOSE: To determine the effects of altered pericyte NF-κB activity on endothelial cell proliferation and identify inflammatory factors involved in this cell-cell signaling. METHODS: Human primary pericytes were transfected with vectors designed to increase or decrease NF-κB activity (or empty vector control). Transfected pericytes were co-cultured with human microvascular endothelial cells (HMVECs) using transwell inserts. HMVEC proliferation was assessed via cell counting at 24 and 48 hr. Secreted cytokines in cell culture supernatants were screened using a Luminex multiplex assay. RESULTS: HMVEC proliferation was greater in the increased pericyte NF-κB activity condition compared to the decreased NF-κB condition at 24 and 48 hr (1.3 fold, p=0.002). At 24 hr, cytokine secretion was greater in the increased NF-κB condition compared to control and decreased NF-κB conditions for 14 cytokines, including interleukin-8 (IL-8; 6.4 fold, p CONCLUSION: NF-κB activation in pericytes caused increased HMVEC proliferation, which may have been mediated by proinflammatory and proangiogenic cytokines known to be under the transcriptional regulation of NF-κB

Percussive Massage Increases Capillary Density in Type I and II Skeletal Muscle Fibers

Capillaries play a critical role in delivering oxygen and nutrients to cells. Skeletal muscle adapts to increased demand by increasing capillary density through a process known as angiogenesis. The effects of alternative therapies such as massage on angiogenic adaptation in skeletal muscle are inconclusive, particularly for newer techniques such as percussive massage. PURPOSE: To investigate the effect of 6 weeks of percussive massage on skeletal muscle myofiber area and angiogenesis. METHODS: 11 healthy young (22±4 yr.) men (n=5) and women (n=6) received 18 sessions of 30-min-percussive massage on their right thigh over the course of 6 weeks. Muscle samples were collected one week before the start of massage sessions and 48 h after the last session from the participant’s treated thigh. Sections from the biopsies were stained with CD31 for capillary analysis and type I myosin heavy chain for fiber type analysis. Capillary per fiber, capillary density, fiber area and fiber type were analyzed before and after massage treatment. RESULTS: The mean cross-sectional area of type I fibers did not change after massage treatment, but type II fiber area decreased by 7.5% (p=0.04). The number of capillaries per fiber increased only for type I fibers (p=0.01) and did not change in type II fibers. Massage increased overall capillary density (capillary per fiber/area) of both type I (p=0.04) and II muscle fibers (p=0.03). CONCLUSION: Although capillary density increased for both muscle fiber types; massage likely affected the two fiber types differently. Whereas increased capillary density of type I fibers was the likely result of angiogenesis, the increase in capillary density for type II fibers was driven largely by a reduction in type II fiber area

De gammeltestamentlige apokryfer og pseudepigrafer og Qumranteksterne

Artiklen fokuserer på jødisk litteratur og centrale spørgsmål om jøderne ret til deres egen religion, makkabæernes legitimitet og bestemmelsen af termerne ”eskatologi” og ”apokalyptik”. Endvidere berøres sammenhængen mellem apokalyptikken og gnosticisme