Hydrodynamic cavitaion venturi tube technique is used for pico and nano bubble generations in coal column flotation. In order to determine the optimal design of hydrodynamic cavitation venture tube for pico and nano b...Hydrodynamic cavitaion venturi tube technique is used for pico and nano bubble generations in coal column flotation. In order to determine the optimal design of hydrodynamic cavitation venture tube for pico and nano bubble generation, a four-factor three-level Central Composite Design of Experimental was conducted for investigating four important design parameters of cavitation venturi tube governing the median size and the volume of pico and nano bubbles. The test results showed that maximum volume of pico and nano bubbles, 65–75%, and minimum mean pico and nano bubble size,150–240 nm, were achieved at the medium ratio of the diameter of outlet of the venturi-tube and diameter of throat(3–4), medium outlet angle(11–13°), high inlet angle(26–27°) and high ratio of the length of the throat and the diameter of throat(2.3–3). Study the effects of the producing pico and nano bubbles on fine coal flotation was performed in a 5 cm diameter 260 cm height flotation column. The optimal percentage of pico and nano bubbles was about 70%, which produced maximum combustible material recovery of 86% with clean coal ash content of 11.7%.展开更多
This paper addresses the issue of Chinese students＇ oral English skills in talking about Chinese culture from the perspective of conversation analysis. To examine their performance in this regard, group discussion da...This paper addresses the issue of Chinese students＇ oral English skills in talking about Chinese culture from the perspective of conversation analysis. To examine their performance in this regard, group discussion data in the classroom were collected for analysis. Their oral skills in talking about Chinese New Year and Christmas, a Western festival, were analyzed and compared to determine their oral performance in describing their native culture. Comments by two native English speakers on the students＇ performance are used to complement the conversation analysis. The results indicate that, compared with their performance regarding Christmas, the students were able to express a wider range of cultural connotations about Chinese New Year in English, but they used significantly fewer correct culturally-loaded words and phrases, and switched to Chinese much more frequently, suggesting unsatisfactory oral skills in describing Chinese culture.展开更多
基金West Virginia State Coal and Energy Research Bureau(WVCERB)the Department of Mining Engineering,West Virginia University
文摘Hydrodynamic cavitaion venturi tube technique is used for pico and nano bubble generations in coal column flotation. In order to determine the optimal design of hydrodynamic cavitation venture tube for pico and nano bubble generation, a four-factor three-level Central Composite Design of Experimental was conducted for investigating four important design parameters of cavitation venturi tube governing the median size and the volume of pico and nano bubbles. The test results showed that maximum volume of pico and nano bubbles, 65–75%, and minimum mean pico and nano bubble size,150–240 nm, were achieved at the medium ratio of the diameter of outlet of the venturi-tube and diameter of throat(3–4), medium outlet angle(11–13°), high inlet angle(26–27°) and high ratio of the length of the throat and the diameter of throat(2.3–3). Study the effects of the producing pico and nano bubbles on fine coal flotation was performed in a 5 cm diameter 260 cm height flotation column. The optimal percentage of pico and nano bubbles was about 70%, which produced maximum combustible material recovery of 86% with clean coal ash content of 11.7%.
文摘This paper addresses the issue of Chinese students＇ oral English skills in talking about Chinese culture from the perspective of conversation analysis. To examine their performance in this regard, group discussion data in the classroom were collected for analysis. Their oral skills in talking about Chinese New Year and Christmas, a Western festival, were analyzed and compared to determine their oral performance in describing their native culture. Comments by two native English speakers on the students＇ performance are used to complement the conversation analysis. The results indicate that, compared with their performance regarding Christmas, the students were able to express a wider range of cultural connotations about Chinese New Year in English, but they used significantly fewer correct culturally-loaded words and phrases, and switched to Chinese much more frequently, suggesting unsatisfactory oral skills in describing Chinese culture.
