388 research outputs found

    A Study of the Application of Supply Chain Management in Construction Industry

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    The concept of construction supply chain (CSC) is defined firstly. Then the authors depict a typical construction supply chain model from the perspectives of partners involved in construction process, analyze the characteristics and attributes of CSC, and identify some problems in CSC. Based-on the definition and principles of supply chain management (SCM), the concept of construction supply chain management (CSCM) are also described in detail. From the perspective of relationship management, a framework for integrated CSCM is developed to guide the effective implement of SCM in construction industry, which includes contractor (supplier) selection, conflict management, risk management, innovation management, performance management and information supporting system. Finally, traditional construction management approaches are compared with integrated CSCM approaches

    Virtual Element Methods Without Extrinsic Stabilization

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    Virtual element methods (VEMs) without extrinsic stabilization in arbitrary degree of polynomial are developed for second order elliptic problems, including a nonconforming VEM and a conforming VEM in arbitrary dimension under the mesh assumption that all the faces of each polytope are simplices. The key is to construct local H(div)H({\rm div})-conforming macro finite element spaces such that the associated L2L^2 projection of the gradient of virtual element functions is computable, and the L2L^2 projector has a uniform lower bound on the gradient of virtual element function spaces in L2L^2 norm. Optimal error estimates are derived for these VEMs. Numerical experiments are provided to test the VEMs without extrinsic stabilization.Comment: 25 pages, 8 figure

    Geometric Decomposition and Efficient Implementation of High Order Face and Edge Elements

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    This paper delves into the world of high-order curl and div elements within finite element methods, providing valuable insights into their geometric properties, indexing management, and practical implementation considerations. It first explores the decomposition of Lagrange finite elements. The discussion then extends to H(div)-conforming finite elements and H(curl)-conforming finite element spaces by choosing different frames at different sub-simplex. The required tangential continuity or normal continuity will be imposed by appropriate choices of the tangential and normal basis. The paper concludes with a focus on efficient indexing management strategies for degrees of freedom, offering practical guidance to researchers and engineers. It serves as a comprehensive resource that bridges the gap between theory and practice in the realm of high-order curl and div elements in finite element methods, which are vital for solving vector field problems and understanding electromagnetic phenomena.Comment: 25 pages, 8 figure

    A Model for Residential Building Energy Consumption Characteristics and Energy Demand: A Case in Chongqing

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    AbstractThis study adopts a bottom-up typical method to establish the microscopic model to simulate the urban residential building energy consumption. The model is composed of a three-hierarchy structure: a) the classification according to the climate; b) according to the energy use; c) according to the energy intensity. Based on the model, energy consumption of urban residential building in Chongqing is calculated as an example. The calculation results of the model and the actual energy consumption are compared and validated. The residential building energy consumption model can be used to analyze the energy consumption in the past years using the existing data, as well as the development trend of the related factors so that the appropriate energy saving measures can be selected properly

    Design and Modeling for 2D Plate Type MR Damper

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    A two-dimensional magnetorheological damper is developed for the engineering two-dimensional damping need. The velocity and pressure distribution model of the two-dimensional plate-type damper, and the damping force calculation model are established based on the Navier-Stokes equation. Several structural and physical parameters, including the working gap δ, the length a, and the width a of the middle slide plate, are analyzed theoretically. The damping performance of the two-dimensional plate-type magnetorheological damper was evaluated using a two-dimensional vibration test-bed, with the effect of the excitation current analyzed. The experimental results suggest a significant influence of Coulomb damping force on the damping force of magnetorheological damper when using appropriate magnetorheological fluid. As the excitation current increases, the damping force of magnetorheological damper becomes larger while the system amplitude decreases gradually in both directions, a maximum reduction of 2.5956 times. It's confirmed that the design of the two-dimensional plate-type magnetorheological damper is reasonable

    Panax Quinquefolius Saponin of Stem and Leaf Attenuates Intermittent High Glucose-Induced Oxidative Stress Injury in Cultured Human Umbilical Vein Endothelial Cells via PI3K/Akt/GSK-3 β

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    Panax quinquefolius saponin of stem and leaf (PQS), the effective parts of American ginseng, is widely used in China as a folk medicine for diabetes and cardiovascular diseases treatment. In our previous studies, we have demonstrated that PQS could improve the endothelial function of type II diabetes mellitus (T2DM) rats with high glucose fluctuation. In the present study, we investigated the protective effects of PQS against intermittent high glucose-induced oxidative damage on human umbilical vein endothelial cells (HUVECs) and the role of phosphatidylinositol 3-kinase kinase (PI3K)/Akt/GSK-3β pathway involved. Our results suggested that exposure of HUVECs to a high glucose concentration for 8 days showed a great decrease in cell viability accompanied by marked MDA content increase and SOD activity decrease. Moreover, high glucose significantly reduced the phosphorylation of Akt and GSK-3β. More importantly, these effects were even more evident in intermittent high glucose condition. PQS treatment significantly attenuated intermittent high glucose-induced oxidative damage on HUVECs and meanwhile increased cell viability and phosphorylation of Akt and GSK-3β of HUVECs. Interestingly, all these reverse effects of PQS on intermittent high glucose-cultured HUVECs were inhibited by PI3K inhibitor LY294002. These findings suggest that PQS attenuates intermittent-high-glucose-induced oxidative stress injury in HUVECs by PI3K/Akt/GSK-3β pathway
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