The cutting simulation of soft tissue is important in virtual surgery. It includes three major challenges in computation: Soft tissue simulation, collision detection, and handling, as well as soft tissue models. In order to address the earlier challenges, we propose a virtual cutting system based on the mass-spring model. In this system, MSM is utilized to simulate the soft tissue model. Residual stress is introduced to the model for simulating the shrinking effect of soft tissue in cutting. Second, a cylinder-based collision detection method is used to supervise the collision between surgical tools and soft tissue. Third, we simulate the cutting operation with a three-stage cutting method with swept volume, B´ezier curve, and an algorithm named shortest distance nodes matching method. In order to verify the system performance, we carry out three validation experiments on the proposed system: Cutting accuracy experiment, collision detection validation, and practical cutting evaluation. Experiments indicate that our system can well perform the shrinking effect of soft tissue in cutting. The system has fast and accurate collision detection. Moreover, the system can reconstruct smooth incisions vividly.
Since asphalt mortar is highly heterogeneous and occurs as an interfacial bonding material between the asphalt-binder and aggregate, it is very important to have a detailed and adequate understanding of its mechanical properties at a multi-scale (micro and macro) level analysis. In this study, the fundamental properties of the asphalt mortar were evaluated and quantified using molecular dynamic simulations. The tensile strength, stress-separation responses, and adhesive-bonding strength were numerically measured and characterised from a micro perspective. Other mechanical properties such as the complex modulus, low-temperature stiffness modulus, hardness, and elastic modulus were also experimentally measured to verify the dynamic simulations and modelling results. In comparison to the macro experimental test results, it was found that the micro-simulated results were superior in terms of characterising the mechanical properties of the asphalt mortar. Whilst the tensile strength, adhesive-bond strength, and hardness of the asphalt mortar changed significantly as a function of aging, the stress-separation responses and elastic modulus were hardly affected. Overall, the study findings indicated that multi-scale characterisation of the mechanical properties of asphalt mortar is a potentially promising methodology for quantitatively evaluating and understanding the mechanical properties.
This paper used to SWOT analysis to analyze the advantages and disadvantages,conditions,opportunities,challenges of internal and external environment for Shaanxi,civil-military integration development,and on this basis points out the development proposals with Shaanxi characteristic,such as WT,WO,ST,SO integration,to provide the theoretical basis and practical guidance for the implementation of civil-military integration in Shaanxi and also lay a foundation for achievement of strategy for a prosperous country with a powerful army uniform.
0D indium halide [1-Me-Pipz] 2 [InCl 6 ]Cl·H 2 O exhibits strong broadband yellow emission with a high PLQY of 52%. This crystal also demonstrated excellent structural and spectral stability, allowing its use in efficient white light-emitting diodes.
Coal and coal gangue spontaneous combustion (CGSC) occurs globally, causing significant environmental pollution. However, its emissions are poorly quantified and are overlooked in global or regional air pollutant emission inventories in previous studies, resulting in the underestimation of its impacts on climate, environment, and public health. This study quantified the emissions of various air pollutants originating from CGSC in Wuhai, a city in China, investigated emission characteristics, and estimated the contribution of CGSC emissions to fine particulate matter (PM2.5) air pollution and related health impacts on a regional scale. The results revealed that the CGSC-related PM2.5 emissions were approximately 4643 t a–1 (95% confidence interval (95% CI): 721; 10447), accounting for 26.3% of the total PM2.5 emissions. Alkanes, alkenes, and aromatics accounted for 69.4, 17.9, and 2.9%, respectively, of the total emissions of volatile organic compounds (VOCs). Due to CGSC emissions, the ambient PM2.5 concentration in Wuhai increased by 5.7 μg m–3 on average, while the nitrate concentration decreased. The number of premature deaths caused by exposure to ambient PM2.5 associated with CGSC reached 381 (95% CI: 290; 452) in Wuhai and surrounding cities in 2017. Urgent control strategies and engineering techniques are needed to mitigate CGSC to protect public health.
Based on the determine and working of the construction scheme of main arch of Yuyuantan butterfly-style bridge,the author shows the advantages of steel pipe concrete technology and analyzes the quality control and survey method of this technology.
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