20,587 research outputs found

    Modelling the thermo-mechanical volume change behaviour of compacted expansive clays

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    Compacted expansive clays are often considered as a possible buffer material in high-level deep radioactive waste disposals. After the installation of waste canisters, the engineered clay barriers are subjected to thermo-hydro-mechanical actions in the form of water infiltration from the geological barrier, heat dissipation from the radioactive waste canisters, and stresses generated by clay swelling under almost confined conditions. The aim of the present work is to develop a constitutive model that is able to describe the behaviour of compacted expansive clays under these coupled thermo-hydro-mechanical actions. The proposed model is based on two existing models: one for the hydro-mechanical behaviour of compacted expansive clays and another for the thermo-mechanical behaviour of saturated clays. The elaborated model has been validated using the thermo-hydro-mechanical test results on the compacted MX80 bentonite. Comparison between the model prediction and the experimental data show that this model is able to reproduce the main features of volume changes: heating at constant suction and pressure induces either expansion or contraction; the mean yield stress changes with variations of suction or temperature

    Linear Global Translation Estimation with Feature Tracks

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    This paper derives a novel linear position constraint for cameras seeing a common scene point, which leads to a direct linear method for global camera translation estimation. Unlike previous solutions, this method deals with collinear camera motion and weak image association at the same time. The final linear formulation does not involve the coordinates of scene points, which makes it efficient even for large scale data. We solve the linear equation based on L1L_1 norm, which makes our system more robust to outliers in essential matrices and feature correspondences. We experiment this method on both sequentially captured images and unordered Internet images. The experiments demonstrate its strength in robustness, accuracy, and efficiency.Comment: Changes: 1. Adopt BMVC2015 style; 2. Combine sections 3 and 5; 3. Move "Evaluation on synthetic data" out to supplementary file; 4. Divide subsection "Evaluation on general data" to subsections "Experiment on sequential data" and "Experiment on unordered Internet data"; 5. Change Fig. 1 and Fig.8; 6. Move Fig. 6 and Fig. 7 to supplementary file; 7 Change some symbols; 8. Correct some typo

    Nursing Care of a Case of Mediastinal Tumor Resection Combined with Postoperative Thoracic Hemorrhage after Video-assisted Thoracoscopic Surgery (VATS)

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    Objective: To summarize the nursing experience of a patient withpostoperative intrathoracic hemorrhage after thoracoscopic-assistedresection of the right upper mediastinal tumor through the original incision.Methods: Summarize the main points of nursing care of postoperativeintrathoracic hemorrhage after thoracoscopic mediastinal surgery, includingobservation and nursing when internal hemorrhage occurs after operation,respiratory management, activity management and pain managementmeasures. Result: After careful care, the patient recovered and dischargedsmoothly. Conclusion: It is particularly important to observe the overallobservation and take timely corresponding nursing measures for patientswith intrathoracic hemorrhage after thoracoscopic mediastinal surgery
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