The phase transformation kinetics of 35CrMo steel during heating have been harnessed to refine thermo-mechanical processing techniques, thereby ensuring the quality of heat-treated components. To accurately forecast t...
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The phase transformation kinetics of 35CrMo steel during heating have been harnessed to refine thermo-mechanical processing techniques, thereby ensuring the quality of heat-treated components. To accurately forecast the austenite phase transformation in 35CrMo steel, a non-isothermal diffusion-type Johnson-Mehl-Avrami-Kolmogorov (J-M-A-K) model was developed under continuous heating conditions. The phase transformation activation energy was determined to be Q = 1.097 x 106 J/mol, with kinetic parameters n = 0.6434 and k0 = 7.8316 x 1052. The adaptive simulated annealing (asa) algorithm was employed to perform inverse estimation, optimizing the J-M-A-K model parameters to n = 0.6306 and k0 = 1.2 x 1053. Taking the cumulative error between the experimental and model values of austenite volume fraction as the objective function, with the minimization of this error as the identification strategy, the optimized model showed an improvement in the prediction correlation coefficient R by 0.285, while the average absolute relative error (AARE) and root-mean-square error (RMSE) decreased by 2.67% and 0.0176, respectively. Through secondary development, the optimized J-M-A-K model was integrated into the SIMHEAT simulation software to simulate the continuous heating of 35CrMo steel. The simulation results correlated highly with experimental data, demonstrating the optimized J-M-A-K model's precision in characterizing the austenitization process of 35CrMo steel during continuous heating.
Study objectives: This study was designed to evaluate how the anesthesiologists in Cairo University Hospitals are adherent in their practice to the latest asa guidelines for management of difficult airway in order to ...
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Study objectives: This study was designed to evaluate how the anesthesiologists in Cairo University Hospitals are adherent in their practice to the latest asa guidelines for management of difficult airway in order to stand on the current status and establish a basis for improvement. Methods: This is a survey study included 190 anesthesiologists from the faculty members of Cairo university hospitals. All of them completed the study questionnaire. Main results: A 77.9% of the responders admitted their use of the asa algorithm during their practice. For anticipated difficult airway, 74% would employ regional anesthesia as first choice while 52% and 54% would use Supraglottic airway devices and awake Fiberoptic respectively. For unanticipated failed intubation with adequate mask ventilation, 90% would use a supraglottic airway device as their first choice while 85% and 90% would wake up the patient, perform awake fiberoptic intubation and make an emergency invasive airway access respectively. For failed intubation with difficult/impossible mask ventilation, 87% would use a supraglottic airway device while 51% and 28% would perform needle cricothyroidotomy and percutaneous tracheostomy respectively. Awake fiberoptic intubation and intubation with direct laryngoscope using intravenous induction and succinylcholine were the most frequently used techniques in different clinical scenarios. Conclusion: The practice of anesthesiologists in Cairo university hospitals is close to the recommendations of the asa guidelines for management of difficult airway. There is increased skills in fiberoptic bronchoscopes and SGA with increased frequency of difficult airway managements training courses;however, they need to improve their skills in awake fiberoptic intubations technique and they need to be trained on invasive airway management access to close the discrepancy between their theoretical choices in different situations and their actual skills. (C) 2015 Production and hosting by E
Considering the present backward situation of the compressor splitter designing level, a multi-objective Combinatorial Optimization Design method is put forward for the splitter design consisting of three core compone...
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ISBN:
(纸本)9780791856659
Considering the present backward situation of the compressor splitter designing level, a multi-objective Combinatorial Optimization Design method is put forward for the splitter design consisting of three core components: the CST parameterized method, the Design of Experiment and the asa optimization algorithm. In the whole optimization design process, the CST parameterized method is developed for the complex geometry modeling and geometric samples generating of splitter. The Design of Experiment is taken used to qualitatively analyze the multiple design variables and adjust their number and scopes. The asa algorithm takes charge of the global optimization of splitter geometry samples, and selects the best geometry conform to the design target. All the relevant optimization components and modules are integrated by the Isight software and be interacted and automatically called by the edited scripts. The effectiveness of the proposed design method is verified through a practical splitter example. Results show that: 1) the CST parameterized method of fourth order or above is of great accurately to fit the splitter geometry, in order to generate variable geometric samples. 2) The Design of Experiment is able to identify the different influence of multiple design variables on the design objectives and lead to the optimization process more targeted. 3) The performance of optimization result is improved significantly, in which the core duct behaves more sensitive to splitter geometry changing and the low-static pressure and high-radial velocity areas reduced to half of the initial design.
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