The non-linear finite element software ABAQUS was used to simulate the dynamic response of a marine supercharged boiler when subjected to impact loading. Shock resistance was analyzed by the time-domain simulation met...The non-linear finite element software ABAQUS was used to simulate the dynamic response of a marine supercharged boiler when subjected to impact loading. Shock resistance was analyzed by the time-domain simulation method. After exhaustive simulations,the effect of air pressure induced by different working conditions on the shock response of a supercharged boiler was reviewed,leading to conclusions about the variability of structural response with different loading parameters. In order to simulate the real impulsive environments of supercharged boilers,the integration of equipment and ship structure was then primarily used to analyze shock response. These distinctly different equipment shock test methods,run under equivalent work conditions,were compared and the causes of discrepancy were analyzed. The main purpose of this paper is to present references for the anti-shock design of marine supercharged boilers.展开更多
Current nitrogen (N) leaching losses and their responses to monthly N additions were investigated under a disturbed pine (Pinus massoniana) forest and a mature monsoon broadleaf forest in southern China. N leaching lo...Current nitrogen (N) leaching losses and their responses to monthly N additions were investigated under a disturbed pine (Pinus massoniana) forest and a mature monsoon broadleaf forest in southern China. N leaching losses from both disturbed and mature forests were quite high (14.6 and 29.2 kg N ha-1 year-1, respectively), accounting for 57% and 80% of their corresponding atmospheric N inputs. N leaching losses were substantially increased following the first 1.5 years of N applications in both forests. The average increases induced by the addition of 50 and 100 kg N ha-1 year-1 were 36.5 and 24.9 kg N ha-1 year-1, respectively, in the mature forest, accounting for 73.0% and 24.9% of the annual amount of N added, and 14.2 and 16.8 kg N ha-1 year-1 in the disturbed forest, accounting for 28.4% and 16.8% of the added N. Great N leaching and a fast N leaching response to N additions in the mature forest might result from long-term N accumulation and high ambient N deposition load (greater than 30 kg N ha-1 year-1 over the past 15 years), whereas in the disturbed forest, it might result from the human disturbance and high ambient N deposition load. These results suggest that both disturbed and mature forests in the study region may be sensitive to increasing N deposition.展开更多
In this paper, the control volume method is used to establish the general expression of entropy generation due to combined convective heat and mass transfer in internal and external fluid streams. Theexpression accoun...In this paper, the control volume method is used to establish the general expression of entropy generation due to combined convective heat and mass transfer in internal and external fluid streams. Theexpression accounts for irreversibilities due to the presence of heat transfer across a finite temperaturedifference, mass transfer across a finite difference in the chemical potential of a species, and due toflow friction. Based on the assumption of local thermodynamic equilibrium, the generalized form ofthe Gibbs equation is used in this analysis. The results are applied to two fundamental problems offorced convection heat and mass transfer in internal and external flows. After minimizing the entropygeneration, useful conclusions are derived that are typical of the second law viewpoint for the definitionof the optimum operation conditions for the specified applications, which is a' valuable criterion foroptimum design of heat and fluid flow devices.展开更多
文摘The non-linear finite element software ABAQUS was used to simulate the dynamic response of a marine supercharged boiler when subjected to impact loading. Shock resistance was analyzed by the time-domain simulation method. After exhaustive simulations,the effect of air pressure induced by different working conditions on the shock response of a supercharged boiler was reviewed,leading to conclusions about the variability of structural response with different loading parameters. In order to simulate the real impulsive environments of supercharged boilers,the integration of equipment and ship structure was then primarily used to analyze shock response. These distinctly different equipment shock test methods,run under equivalent work conditions,were compared and the causes of discrepancy were analyzed. The main purpose of this paper is to present references for the anti-shock design of marine supercharged boilers.
基金supported by the National Natural Science Foundation of China (No.30670392)the Knowledge InnovationProgram of the Chinese Academy of Sciences (Nos.KZCX2-YW-432-2 and KSCX2-SW-133).
文摘Current nitrogen (N) leaching losses and their responses to monthly N additions were investigated under a disturbed pine (Pinus massoniana) forest and a mature monsoon broadleaf forest in southern China. N leaching losses from both disturbed and mature forests were quite high (14.6 and 29.2 kg N ha-1 year-1, respectively), accounting for 57% and 80% of their corresponding atmospheric N inputs. N leaching losses were substantially increased following the first 1.5 years of N applications in both forests. The average increases induced by the addition of 50 and 100 kg N ha-1 year-1 were 36.5 and 24.9 kg N ha-1 year-1, respectively, in the mature forest, accounting for 73.0% and 24.9% of the annual amount of N added, and 14.2 and 16.8 kg N ha-1 year-1 in the disturbed forest, accounting for 28.4% and 16.8% of the added N. Great N leaching and a fast N leaching response to N additions in the mature forest might result from long-term N accumulation and high ambient N deposition load (greater than 30 kg N ha-1 year-1 over the past 15 years), whereas in the disturbed forest, it might result from the human disturbance and high ambient N deposition load. These results suggest that both disturbed and mature forests in the study region may be sensitive to increasing N deposition.
文摘In this paper, the control volume method is used to establish the general expression of entropy generation due to combined convective heat and mass transfer in internal and external fluid streams. Theexpression accounts for irreversibilities due to the presence of heat transfer across a finite temperaturedifference, mass transfer across a finite difference in the chemical potential of a species, and due toflow friction. Based on the assumption of local thermodynamic equilibrium, the generalized form ofthe Gibbs equation is used in this analysis. The results are applied to two fundamental problems offorced convection heat and mass transfer in internal and external flows. After minimizing the entropygeneration, useful conclusions are derived that are typical of the second law viewpoint for the definitionof the optimum operation conditions for the specified applications, which is a' valuable criterion foroptimum design of heat and fluid flow devices.
