Modem packing technology is presented in terms of correlations and criteria for an extensive evaluation of up-to-date packing design used in current mass transfer operations. The corresponding basic information covers...Modem packing technology is presented in terms of correlations and criteria for an extensive evaluation of up-to-date packing design used in current mass transfer operations. The corresponding basic information covers the process engineering aspects, e.g. volumetric effectiveness and optimum geometry of the packing, and the techno-economic aspects, e.g. when selecting a packing adopted in practice for a certain application task. The correlations required for this investigation are derived and evaluated on the basis of a comprehensive experimental re- search by testing and comparison of modem packings, such as Raschig Super-Rings and reference packings. The results thus obtained are correlated and presented in graphic presentation of diagrams, figures and tables.展开更多
Recent advances in broadband technology have caused forwarding engines to handle pack- ets with over 10 gigabit per second. In this paper, we present a high-speed forwarding pipeline which can finish all of the routin...Recent advances in broadband technology have caused forwarding engines to handle pack- ets with over 10 gigabit per second. In this paper, we present a high-speed forwarding pipeline which can finish all of the routing and forwarding tasks in the way of pipelining. We also establish the analysis model of the pipeline with which one can evaluate some key performance parameters of the forwarding engine such as forwarding rate and forwarding delay. We find that the pipeline is of good scalability and can forward unicast packets up to the speed of 40Gbit/s.展开更多
A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of whee...A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of wheel structural unit,suspension unit,and connecting device unit between suspension and load platform,some new locomotion system configurations were proposed and the metrics and indexes to evaluate the performance of the new locomotion system were analyzed.Performance evaluation and comparison between two LER with locomotion systems of different configurations were analyzed.The analysis results indicate that the new locomotion system configuration has good trafficability performance.展开更多
The objective of Performance-Based Earthquake Engineering （PBEE） is the analysis of performance objectives with a specified annual probability of exceedance. Increasingly undesirable performance is caused by increas...The objective of Performance-Based Earthquake Engineering （PBEE） is the analysis of performance objectives with a specified annual probability of exceedance. Increasingly undesirable performance is caused by increasing levels of strong ground motion having decreasing annual probabilities of exceedance. The development of this methodology includes three steps： （1） evaluation of the distribution of ground motion at a site; （2） evaluation of the distribution of system response; （3） evaluation of the probability of exceeding decision variables within a given time period, given appropriate damage measures. The work has taken a systematic approach to determine the impact of increasing levels of detail in site characterization on the accuracy of ground motion and site effects predictions. Complementary studies have investigated the use of the following models for evaluating site effects： （1） amplification factors defined on the basis of generalized site categories, （2） one-dimensional ground response analysis, and （3） two-dimensional ground response analysis for surface topography on ground motion. The paper provides a brief synthesis of ground motion and site effects analysis procedures within a Performance-Based Design framework. It focuses about the influence on the evaluation of site effects in some active regions by different shear waves velocity measurements Down Hole （D-H）, Cross Hole （C-H）, Seismic Dilatometer Marchetti Test （SDMT） and by different variation of shear modulus and damping ratio with strain level and depth from different laboratory dynamic tests for soil characterization： Resonant Column Test （RCT）, Cyclic Loading Torsional Shear Test （CLTST）.展开更多
This paper presents the performance evaluation of a regenerative pump to increase its efficiency using optimal design method. Two design parameters which define the shape of the pump impeller, are introduced and analy...This paper presents the performance evaluation of a regenerative pump to increase its efficiency using optimal design method. Two design parameters which define the shape of the pump impeller, are introduced and analyzed. Pump performance is evaluated by numerical simulation and design of experiments(DOE). To analyze three-dimensional flow field in the pump, general analysis code, CFX, is used in the present work. Shear stress turbulence model is employed to estimate the eddy viscosity. Experimental apparatus with an open-loop facility is set up for measuring the pump performance. Pump performance, efficiency and pressure, obtained from numerical simulation are validated by comparison with the results of experiments. Throughout the shape optimization of the pump impeller at the operating flow condition, the pump efficiency is successfully increased by 3 percent compared to the reference pump. It is noted that the pressure increase of the optimum pump is mainly caused by higher momentum force generated inside blade passage due to the optimal blade shape. Comparisons of pump internal flow on the reference and optimum pump are also investigated and discussed in detail.展开更多
文摘Modem packing technology is presented in terms of correlations and criteria for an extensive evaluation of up-to-date packing design used in current mass transfer operations. The corresponding basic information covers the process engineering aspects, e.g. volumetric effectiveness and optimum geometry of the packing, and the techno-economic aspects, e.g. when selecting a packing adopted in practice for a certain application task. The correlations required for this investigation are derived and evaluated on the basis of a comprehensive experimental re- search by testing and comparison of modem packings, such as Raschig Super-Rings and reference packings. The results thus obtained are correlated and presented in graphic presentation of diagrams, figures and tables.
基金Supported by the National High Technology Research and Development Program of China (No.2003AA103510).
文摘Recent advances in broadband technology have caused forwarding engines to handle pack- ets with over 10 gigabit per second. In this paper, we present a high-speed forwarding pipeline which can finish all of the routing and forwarding tasks in the way of pipelining. We also establish the analysis model of the pipeline with which one can evaluate some key performance parameters of the forwarding engine such as forwarding rate and forwarding delay. We find that the pipeline is of good scalability and can forward unicast packets up to the speed of 40Gbit/s.
基金Supported by National "863" High-Tech Program (No.2006AA04Z231)Foundation of State Key Laboratory of Robotics and Systems (No.SKLRS-200801A02)+1 种基金the College Discipline Innovation Wisdom Plan (No.B07018)Natural Science Foundation of Heilongjiang Province (No.ZJG0709)
文摘A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of wheel structural unit,suspension unit,and connecting device unit between suspension and load platform,some new locomotion system configurations were proposed and the metrics and indexes to evaluate the performance of the new locomotion system were analyzed.Performance evaluation and comparison between two LER with locomotion systems of different configurations were analyzed.The analysis results indicate that the new locomotion system configuration has good trafficability performance.
文摘The objective of Performance-Based Earthquake Engineering （PBEE） is the analysis of performance objectives with a specified annual probability of exceedance. Increasingly undesirable performance is caused by increasing levels of strong ground motion having decreasing annual probabilities of exceedance. The development of this methodology includes three steps： （1） evaluation of the distribution of ground motion at a site; （2） evaluation of the distribution of system response; （3） evaluation of the probability of exceeding decision variables within a given time period, given appropriate damage measures. The work has taken a systematic approach to determine the impact of increasing levels of detail in site characterization on the accuracy of ground motion and site effects predictions. Complementary studies have investigated the use of the following models for evaluating site effects： （1） amplification factors defined on the basis of generalized site categories, （2） one-dimensional ground response analysis, and （3） two-dimensional ground response analysis for surface topography on ground motion. The paper provides a brief synthesis of ground motion and site effects analysis procedures within a Performance-Based Design framework. It focuses about the influence on the evaluation of site effects in some active regions by different shear waves velocity measurements Down Hole （D-H）, Cross Hole （C-H）, Seismic Dilatometer Marchetti Test （SDMT） and by different variation of shear modulus and damping ratio with strain level and depth from different laboratory dynamic tests for soil characterization： Resonant Column Test （RCT）, Cyclic Loading Torsional Shear Test （CLTST）.
基金supported by a grant(16AUDPB083704-03)from Architecture&Urban Development Research Program funded by Ministry of Land,Infrastructure and Transport of Korean government
文摘This paper presents the performance evaluation of a regenerative pump to increase its efficiency using optimal design method. Two design parameters which define the shape of the pump impeller, are introduced and analyzed. Pump performance is evaluated by numerical simulation and design of experiments(DOE). To analyze three-dimensional flow field in the pump, general analysis code, CFX, is used in the present work. Shear stress turbulence model is employed to estimate the eddy viscosity. Experimental apparatus with an open-loop facility is set up for measuring the pump performance. Pump performance, efficiency and pressure, obtained from numerical simulation are validated by comparison with the results of experiments. Throughout the shape optimization of the pump impeller at the operating flow condition, the pump efficiency is successfully increased by 3 percent compared to the reference pump. It is noted that the pressure increase of the optimum pump is mainly caused by higher momentum force generated inside blade passage due to the optimal blade shape. Comparisons of pump internal flow on the reference and optimum pump are also investigated and discussed in detail.
