Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fractur...Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fracture behavior. The results show that eutectic Si undergoes stubbing, necking, fragmentation, and growth in the initial stage (250 min); in the middle solution stage (250 to 400 min), the eutectic Si morphology has no significant change, only the degree of spheroidizing becomes higher; after 600 min, the growth of eutectic Si is a coarsening process controlled by diffusion and follows the Liftshitz-Slyozov-Wangner (LSW) model, and the eutectic Si morphology deteriorates due to the occurrence of facets and lap. Based on the quantitative measure and regression analysis, the eutectic Si morphology has a remarkable influence on mechanical properties and fracture behavior.展开更多
In this paper, the authors analyze the impact of the specific ownership structure of the banking sector in Czech and Slovakia on the performance and applied strategies of particular banks during times of crisis. Did t...In this paper, the authors analyze the impact of the specific ownership structure of the banking sector in Czech and Slovakia on the performance and applied strategies of particular banks during times of crisis. Did the multinational banks pursue a coherent regional strategy to cope with the risks resulting from the crisis, or did they focus on finding local solutions？ The aim of this paper is to find answers to these questions. A case study is going to be used as a basic research method. Two members （Slovak and Czech） of four multinational banking groups are examined in the crisis year 2009, whereby both a qualitative analysis of the annual reports regarding strategic business or risk management decisions and a comparative quantitative analysis of selected financial data and risk indicators are employed. The authors have found that Czech and Slovak banks generally tried to follow the main strategic directions given by their parent banks during the financial crisis. However, particular financial results and risk profiles of respective subsidiaries of multinational banks still differ because of market factors specific to the different countries in which the subsidiaries are located.展开更多
In this paper, a study related to the expected performance behaviour of present 3-level cache system for multi-core systems is presented. For this a queuing model for present 3-level cache system for multi-core proces...In this paper, a study related to the expected performance behaviour of present 3-level cache system for multi-core systems is presented. For this a queuing model for present 3-level cache system for multi-core processors is developed and its possible performance has been analyzed with the increase in number of cores. Various important performance parameters like access time and utilization of individual cache at different level and overall average access time of the cache system is determined. Results for up to 1024 cores have been reported in this paper.展开更多
This work presents a multi-criteria analysis of the MAC （media access control） layer misbehavior of the IEEE （Institute of Electrical and Electronics Engineers） 802.11 standard, whose principle is to cheat at the ...This work presents a multi-criteria analysis of the MAC （media access control） layer misbehavior of the IEEE （Institute of Electrical and Electronics Engineers） 802.11 standard, whose principle is to cheat at the protocol to increase the transmission rate by greedy nodes at the expense of the other honest nodes. In fact, IEEE 802.11 forces nodes for access to the channel to wait for a back off interval, randomly selected from a specified range, before initiating a transmission. Greedy nodes may wait for smaller back-off intervals than honest nodes, and then obtaining an unfair assignment. In the first of our works a state of art on the research on IEEE 802.11 MAC layer misbehavior are presented. Then the impact of this misbehavior at the reception is given, and we will generalize this impact on a large scale. An analysis of the correlation between the throughput and the inter-packets time is given. Afterwards, we will define a new metric for measuring the performance and capability of the network.展开更多
Because zirconium alloy cladding is the first containment barrier for fission products, its mechanical integrity is the most important concern. In view of the mechanical integrity, stress and strain are the main facto...Because zirconium alloy cladding is the first containment barrier for fission products, its mechanical integrity is the most important concern. In view of the mechanical integrity, stress and strain are the main factors that affect the cladding performance during normal or off-normal operation, which induces force interaction between the pellet and cladding. In the case of a normal operation period, to estimate the cladding stress and strain, various models and codes have been developed using a simplified 1D （one-dimensional） assumption. However, in the case of a slow ramp during start-up and shut-down and a fast transient such as an AOO （anticipated operational occurrence）, it is difficult for a 1D model to simulate the cladding stress and strain accurately due to its modeling limitation. To model a large deformation along the radial and axial directions such as a ＂＇ballooning＂ phenomenon, FE （finite element） modeling, which can simulate a higher degree of freedom, is an indispensable requirement. In this work, an axisymmetric two-dimensional FE module, which will be integrated into the transient fuel performance code, has been developed. To solve the mechanical equilibrium of the pellet-cladding system, taking into account the geometrical and material non-linearities, the FE module employs an ESF （effective-stress-function） algorithm. Verifications of the FE module for the cases of thermal and elastic analyes were performed using the results of ANSYS 13.0.展开更多
The goal of this work is to investigate the seismic behaviour of plan-asymmetric structures by considering the least seismic-resistant directions and the spatial features of the seismic event. New tools for the analys...The goal of this work is to investigate the seismic behaviour of plan-asymmetric structures by considering the least seismic-resistant directions and the spatial features of the seismic event. New tools for the analysis of the seismic behaviour of plan-asymmetric structures are herein presented and the concepts of ＂Polar Spectrum＂ and limit domains are discussed. In particular, the capacity of the structure is described by using the limit domains based on the Non Linear Static Procedures, while the seismic demand is analysed by introducing a new representation of the spectral response. This representation is based on the construction of a spectral surface obtained by the spectral seismic response for different in-plan directions and the in-plan projection of this surface is herein defined ＂Polar Spectrum＂. The obtained results for two benchmark structures, verified by means of non-linear incremental dynamic analyses, have pointed out that non-linear static analyses, carried out for different in-plan directions of the incoming seismic action, have allowed us to accurately evaluate the least seismic resistant directions.展开更多
文摘Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fracture behavior. The results show that eutectic Si undergoes stubbing, necking, fragmentation, and growth in the initial stage (250 min); in the middle solution stage (250 to 400 min), the eutectic Si morphology has no significant change, only the degree of spheroidizing becomes higher; after 600 min, the growth of eutectic Si is a coarsening process controlled by diffusion and follows the Liftshitz-Slyozov-Wangner (LSW) model, and the eutectic Si morphology deteriorates due to the occurrence of facets and lap. Based on the quantitative measure and regression analysis, the eutectic Si morphology has a remarkable influence on mechanical properties and fracture behavior.
文摘In this paper, the authors analyze the impact of the specific ownership structure of the banking sector in Czech and Slovakia on the performance and applied strategies of particular banks during times of crisis. Did the multinational banks pursue a coherent regional strategy to cope with the risks resulting from the crisis, or did they focus on finding local solutions？ The aim of this paper is to find answers to these questions. A case study is going to be used as a basic research method. Two members （Slovak and Czech） of four multinational banking groups are examined in the crisis year 2009, whereby both a qualitative analysis of the annual reports regarding strategic business or risk management decisions and a comparative quantitative analysis of selected financial data and risk indicators are employed. The authors have found that Czech and Slovak banks generally tried to follow the main strategic directions given by their parent banks during the financial crisis. However, particular financial results and risk profiles of respective subsidiaries of multinational banks still differ because of market factors specific to the different countries in which the subsidiaries are located.
文摘In this paper, a study related to the expected performance behaviour of present 3-level cache system for multi-core systems is presented. For this a queuing model for present 3-level cache system for multi-core processors is developed and its possible performance has been analyzed with the increase in number of cores. Various important performance parameters like access time and utilization of individual cache at different level and overall average access time of the cache system is determined. Results for up to 1024 cores have been reported in this paper.
文摘This work presents a multi-criteria analysis of the MAC （media access control） layer misbehavior of the IEEE （Institute of Electrical and Electronics Engineers） 802.11 standard, whose principle is to cheat at the protocol to increase the transmission rate by greedy nodes at the expense of the other honest nodes. In fact, IEEE 802.11 forces nodes for access to the channel to wait for a back off interval, randomly selected from a specified range, before initiating a transmission. Greedy nodes may wait for smaller back-off intervals than honest nodes, and then obtaining an unfair assignment. In the first of our works a state of art on the research on IEEE 802.11 MAC layer misbehavior are presented. Then the impact of this misbehavior at the reception is given, and we will generalize this impact on a large scale. An analysis of the correlation between the throughput and the inter-packets time is given. Afterwards, we will define a new metric for measuring the performance and capability of the network.
文摘Because zirconium alloy cladding is the first containment barrier for fission products, its mechanical integrity is the most important concern. In view of the mechanical integrity, stress and strain are the main factors that affect the cladding performance during normal or off-normal operation, which induces force interaction between the pellet and cladding. In the case of a normal operation period, to estimate the cladding stress and strain, various models and codes have been developed using a simplified 1D （one-dimensional） assumption. However, in the case of a slow ramp during start-up and shut-down and a fast transient such as an AOO （anticipated operational occurrence）, it is difficult for a 1D model to simulate the cladding stress and strain accurately due to its modeling limitation. To model a large deformation along the radial and axial directions such as a ＂＇ballooning＂ phenomenon, FE （finite element） modeling, which can simulate a higher degree of freedom, is an indispensable requirement. In this work, an axisymmetric two-dimensional FE module, which will be integrated into the transient fuel performance code, has been developed. To solve the mechanical equilibrium of the pellet-cladding system, taking into account the geometrical and material non-linearities, the FE module employs an ESF （effective-stress-function） algorithm. Verifications of the FE module for the cases of thermal and elastic analyes were performed using the results of ANSYS 13.0.
文摘The goal of this work is to investigate the seismic behaviour of plan-asymmetric structures by considering the least seismic-resistant directions and the spatial features of the seismic event. New tools for the analysis of the seismic behaviour of plan-asymmetric structures are herein presented and the concepts of ＂Polar Spectrum＂ and limit domains are discussed. In particular, the capacity of the structure is described by using the limit domains based on the Non Linear Static Procedures, while the seismic demand is analysed by introducing a new representation of the spectral response. This representation is based on the construction of a spectral surface obtained by the spectral seismic response for different in-plan directions and the in-plan projection of this surface is herein defined ＂Polar Spectrum＂. The obtained results for two benchmark structures, verified by means of non-linear incremental dynamic analyses, have pointed out that non-linear static analyses, carried out for different in-plan directions of the incoming seismic action, have allowed us to accurately evaluate the least seismic resistant directions.
