Dynamic analysis of flexible mechanical systems using LATDYN

A 3-D, finite element based simulation tool for flexible multibody systems is presented. Hinge degrees-of-freedom is built into equations of motion to reduce geometric constraints. The approach avoids the difficulty in selecting deformation modes for flexible components by using assumed mode method. The tool is applied to simulate a practical space structure deployment problem. Results of examples demonstrate the capability of the code and approach

A finite element approach for the dynamic analysis of joint-dominated structures

A finite element method to model dynamic structural systems undergoing large rotations is presented. The dynamic systems are composed of rigid joint bodies and flexible beam elements. The configurations of these systems are subject to change due to the relative motion in the joints among interconnected elastic beams. A body fixed reference is defined for each joint body to describe the joint body's displacements. Using the finite element method and the kinematic relations between each flexible element and its corotational reference, the total displacement field of an element, which contains gross rigid as well as elastic effects, can be derived in terms of the translational and rotational displacements of the two end nodes. If one end of an element is hinged to a joint body, the joint body's displacements and the hinge degree of freedom at the end are used to represent the nodal displacements. This results in a highly coupled system of differential equations written in terms of hinge degrees of freedom as well as the rotational and translational displacements of joint bodies and element nodes

Effects of caffeoylxanthiazonoside on airway inflammation in an allergic asthma mice model

Purpose: To investigate the inhibitory effects of caffeoylxanthiazonoside (CYT) on airway inflammation in mice and its mechanism of action. Methods: An allergic asthma mice model was established by intraperitoneal injection and aerosol nebulization with ovalbumin (OVA). After treatment with CYT, the blood and bronchoalveolar lavage fluid (BALF) were collected from the mice. The leukocytes were classified and counted with Giemsa solution. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of IgE, and IL-4, IL-5, IL-13 and IFN-γ in the BALF of mice. Lung tissues were obtained from the mice and MUC5AC protein expression was measured by western blot. Results: CYT significantly decreased the serum level of IgE in asthmatic mice. Inflammatory cells in BALF of mice were markedly reduced (p < 0.05) by CYT treatment at varying doses (10, 20, and 40 mg/kg). Treatment with CYT also significantly suppressed the cytokines of IL-4, IL-5 and IL-13 and increased the IFN-γ in the BLAF of OVA-induced allergic asthma mice (p < 0.05). Western blot results indicate that CYT treatment significantly decreased the expression of MUC5AC protein in the lung tissues of asthmatic mice. In addition, no significant effects on the body weight of the mice were found after CYT treatment. Conclusion: Caffeoylxanthiazonoside inhibits airway inflammation in allergic asthma mice by altering Th1/Th2 via re-balancing of related cytokines and downregulation of lung MUC5AC protein expression. Therefore, this compound can potentially be developed for the therapeutic management of inflammation in allergic asthma

A STUDY ON THE BENEFITS OF SPORTS TOURISM ON CITY MARKETING

The purpose of this study is to explore the benefits of sports tourism on city marketing. In recent years, Taiwan has been actively striving for the marketing of large-scale sports events in the development of international sports. The host city uses the resources invested before the holding of the sports event to develop sports tourism attractions, develop sports tourism policies, and make good use of marketing and promotion strategies to shape the city’s image; and uses media marketing as a tourism promotion tool to expand Taiwan’s sports tourism facets which would bring huge tourism effects. This study organizes the research of past scholars by way of literature discussion, and then collects, organizes and analyzes the data. It is concluded that Taiwan has opened up its international reputation through international large-scale sports events and city marketing. From the experience of hosting international large-scale events, Taiwan not only attracts countless domestic and foreign tourists, but also promotes its city’s culture, tourism, and economy. The vigorous development of related industries, the enhancement of sports tourism quality and the improvement of sports tourism image in Taiwan are also achieved. Finally, international large-scale events revitalize the city to bring business opportunities and make such events the pride of the city. Therefore, this study serves as a reference for future exploration of sports tourism development and city marketing issues, integrating relevant resources, and providing reference for relevant organizations to jointly build Taiwan as a sports tourism island. JEL: L10; L80; L83 Article visualizations

Comparison between simulation and experimental result of the scale down vertical concrete cask under the historical earthquake hit

In recent years, the final disposal facility for the long-term storage of high radioactive waste is an important issue and an urgent task for nuclear Industry. This study is focus on the understanding the procedure of dry storage system in a nuclear power plant. The dry storage system is known as transportable storage canister (TSC) packing by using spent fuel placed in vertical concrete cask (VCC) or VCC with add-on-shell (AOS) canister and then those conveyed VCC or AOS will be put on the concrete pad. A numerical simulation for evaluation the behavior of VCC and AOC under the earthquake hits is used the finite element model by LS-DYNA and the real seismic behavior is obtained using shaking table test. Test results indicate that the simulation by numerical model can slightly simulate the dynamic records by shaking table test. This is because that the behavior of shaking table test is the rocking motion but the numerical model is the sliding motion. The surface roughness between the cask and concrete pad is an important variable and it needs more numerical simulation to solve the interface and friction coefficient between the cask and concrete pad

Large Angle Transient Dynamics (LATDYN) user's manual

A computer code for modeling the large angle transient dynamics (LATDYN) of structures was developed to investigate techniques for analyzing flexible deformation and control/structure interaction problems associated with large angular motions of spacecraft. This type of analysis is beyond the routine capability of conventional analytical tools without simplifying assumptions. In some instances, the motion may be sufficiently slow and the spacecraft (or component) sufficiently rigid to simplify analyses of dynamics and controls by making pseudo-static and/or rigid body assumptions. The LATDYN introduces a new approach to the problem by combining finite element structural analysis, multi-body dynamics, and control system analysis in a single tool. It includes a type of finite element that can deform and rotate through large angles at the same time, and which can be connected to other finite elements either rigidly or through mechanical joints. The LATDYN also provides symbolic capabilities for modeling control systems which are interfaced directly with the finite element structural model. Thus, the nonlinear equations representing the structural model are integrated along with the equations representing sensors, processing, and controls as a coupled system

Giant lipoma arising from deep lobe of the parotid gland

BACKGROUND: Lipomas are common benign soft tissue neoplasms but they are found very rarely in the deep lobe of parotid gland. Surgical intervention in these tumors is challenging because of the proximity of the facial nerve, and thus knowledge of the anatomy and meticulous surgical technique are essential. CASE PRESENTATION: A 71-year-old female presented with a large asymptomatic mass, which had occupied the left facial area for over the past fifteen years, and she requested surgical excision for a cosmetically better facial appearance. The computed tomography (CT) scan showed a well-defined giant lipoma arising from the left deep parotid gland. The lipoma was successfully enucleated after full exposure and mobilization of the overlying facial nerve branches. The surgical specimen measured 9 × 6 cm in size, and histopathology revealed fibrolipoma. The patient experienced an uneventful recovery, with a satisfying facial contour and intact facial nerve function. CONCLUSION: Giant lipomas involving the deep parotid lobe are extremely rare. The high-resolution CT scan provides an accurate and cost-effective preoperative investigative method. Surgical management of deep lobe lipoma should be performed by experienced surgeons due to the need for meticulous dissection of the facial nerve branches. Superficial parotidectomy before deep lobe lipoma removal may be unnecessary in selected cases because preservation of the superficial lobe may contribute to a better aesthetic and functional result