Heating the oil shale by current underground to accomplish in-situ transformation process, is a viable direction. The electrical properties of oil shale under different temperatures, especially the resistance, become ...Heating the oil shale by current underground to accomplish in-situ transformation process, is a viable direction. The electrical properties of oil shale under different temperatures, especially the resistance, become important. Charging oil shale underground to heat oil shale till kerogen's decomposition temperature, then crude oil and other gases can be generated. The resistance of the oil shale samples was measured by Direct Current (DC) quadripole method to find out the variation rules of resistance value. In the experiments, oil shale presented its semiconductor property. When heated till 350℃-450℃, its resistance changed greatly, optional for heating and cracking. The porosity, oil content, media and composition affected the resistance largely.展开更多
The Savonius rotor is a vertical axis-wind machine composed of two half cylindrical blades presenting a central gap. It is a slow velocity machine compared with horizontal wind machines. Its efficiency is about twenty...The Savonius rotor is a vertical axis-wind machine composed of two half cylindrical blades presenting a central gap. It is a slow velocity machine compared with horizontal wind machines. Its efficiency is about twenty per cent. In this work experimental tests are presented using two kind of deflectors placed in front of the resistive blade. Such disposition allows to hide the resistant blade and to guide the flow toward the motrice blade. Two deflectors have been used： a short one and a long one. The results obtained in wind tunnel have shown that the long deflector is the more efficient, essentially for high values of the tip speed ratio. One has been interested, using a numerical approach, in the study of the influence of a wall on the aerodynamical field near the rotor.展开更多
An empirical study is conducted to examine the effect of constructing sense relations in vocabulary teaching. Fifty subjects are divided into two groups： the controlled group which was taught with traditional method,...An empirical study is conducted to examine the effect of constructing sense relations in vocabulary teaching. Fifty subjects are divided into two groups： the controlled group which was taught with traditional method, and the experimental group to which sense relation strategy was applied in vocabulary instruction. At the end of the experiment instruction, a test （depth of vocabulary knowledge measure） was given to examine the teaching effects of the two vocabulary teaching strategies. The target words in the tests were selected from the word list that had been taught during the experiment time. A delayed vocabulary posttest was given to the subjects two weeks after examining the long-term retention effect. The third test was administered with different targets words which were selected from a different intensive reading material which wass new to the subjects. The experiment proves that constructing sense relations in vocabulary teaching could produce satisfactory results by enhancing students＇ lexical capacity and long-term retention.展开更多
The main propose of this research was to develop a two-step biodiesel production technique from animal fat as a raw material. The developed process consists ofesterification and transesterification steps. With special...The main propose of this research was to develop a two-step biodiesel production technique from animal fat as a raw material. The developed process consists ofesterification and transesterification steps. With special attention to optimize the first step is acid catalyzed esterification to reduce free fatty acid content and the second step is alkali catalyzed transesterification for converting triglyceride to fatty acid methyl ester or biodiesel. Animal fat containing 78.80 mg KOH/g of high acid value and molecular weight of 851 g/mol with the highest oleic acid content was used as raw material. Respond surface methodology （RSM） was applied for the experiment design. This were 20 experiments involving the three investigated variables of methanol to animal fat ratio, amount of sulfuric acid catalyst and reaction time that were studied on esterification to optimize the condition for decreasing acid value in animal fat less than 2 mg KOH/g. The animal fat with low acid value was further experimented in transesterification step to obtain fatty acid methyl ester or biodiesel. Animal fat biodiesel is further investigated by determining its fuel properties according to the ASTM standard test method.展开更多
Theory of film condensation heat transfer(FCHT) for vapor condensed on horizontal tube bundle(HTB) is vital to many industry processes.Meanwhile,the inundation effect is the key to model the film condensation heat tra...Theory of film condensation heat transfer(FCHT) for vapor condensed on horizontal tube bundle(HTB) is vital to many industry processes.Meanwhile,the inundation effect is the key to model the film condensation heat transfer coefficient(CHTC) on HTB.This paper proposed a new experimental method,homologous method,to obtain the inundation effect precisely.Based on the requirements of the new test method,a new test facility was designed and established.Then,the superiority of homologous method for inundation effect was investigated based on experiment result and theoretic analysis.The results showed that the homogenous method can effectively control the experimental error of inundation effect,which is less than 50% of the error of CHTC,and less than 30% of the error of the inundation effect gained by routine method.The new test facility built for the homogenous method is excellent in obtaining the accurate inundation effect of film condensation on HTB.All the result is a foundation of the theoretical development of the FCHT on HTB.展开更多
文摘Heating the oil shale by current underground to accomplish in-situ transformation process, is a viable direction. The electrical properties of oil shale under different temperatures, especially the resistance, become important. Charging oil shale underground to heat oil shale till kerogen's decomposition temperature, then crude oil and other gases can be generated. The resistance of the oil shale samples was measured by Direct Current (DC) quadripole method to find out the variation rules of resistance value. In the experiments, oil shale presented its semiconductor property. When heated till 350℃-450℃, its resistance changed greatly, optional for heating and cracking. The porosity, oil content, media and composition affected the resistance largely.
文摘The Savonius rotor is a vertical axis-wind machine composed of two half cylindrical blades presenting a central gap. It is a slow velocity machine compared with horizontal wind machines. Its efficiency is about twenty per cent. In this work experimental tests are presented using two kind of deflectors placed in front of the resistive blade. Such disposition allows to hide the resistant blade and to guide the flow toward the motrice blade. Two deflectors have been used： a short one and a long one. The results obtained in wind tunnel have shown that the long deflector is the more efficient, essentially for high values of the tip speed ratio. One has been interested, using a numerical approach, in the study of the influence of a wall on the aerodynamical field near the rotor.
文摘An empirical study is conducted to examine the effect of constructing sense relations in vocabulary teaching. Fifty subjects are divided into two groups： the controlled group which was taught with traditional method, and the experimental group to which sense relation strategy was applied in vocabulary instruction. At the end of the experiment instruction, a test （depth of vocabulary knowledge measure） was given to examine the teaching effects of the two vocabulary teaching strategies. The target words in the tests were selected from the word list that had been taught during the experiment time. A delayed vocabulary posttest was given to the subjects two weeks after examining the long-term retention effect. The third test was administered with different targets words which were selected from a different intensive reading material which wass new to the subjects. The experiment proves that constructing sense relations in vocabulary teaching could produce satisfactory results by enhancing students＇ lexical capacity and long-term retention.
文摘The main propose of this research was to develop a two-step biodiesel production technique from animal fat as a raw material. The developed process consists ofesterification and transesterification steps. With special attention to optimize the first step is acid catalyzed esterification to reduce free fatty acid content and the second step is alkali catalyzed transesterification for converting triglyceride to fatty acid methyl ester or biodiesel. Animal fat containing 78.80 mg KOH/g of high acid value and molecular weight of 851 g/mol with the highest oleic acid content was used as raw material. Respond surface methodology （RSM） was applied for the experiment design. This were 20 experiments involving the three investigated variables of methanol to animal fat ratio, amount of sulfuric acid catalyst and reaction time that were studied on esterification to optimize the condition for decreasing acid value in animal fat less than 2 mg KOH/g. The animal fat with low acid value was further experimented in transesterification step to obtain fatty acid methyl ester or biodiesel. Animal fat biodiesel is further investigated by determining its fuel properties according to the ASTM standard test method.
基金supported by the National Natural Science Foundation of China (Grant No. 51078053)the Fundamental Research Funds for the Central Universities of China (Grant No. DUT11ZD105)
文摘Theory of film condensation heat transfer(FCHT) for vapor condensed on horizontal tube bundle(HTB) is vital to many industry processes.Meanwhile,the inundation effect is the key to model the film condensation heat transfer coefficient(CHTC) on HTB.This paper proposed a new experimental method,homologous method,to obtain the inundation effect precisely.Based on the requirements of the new test method,a new test facility was designed and established.Then,the superiority of homologous method for inundation effect was investigated based on experiment result and theoretic analysis.The results showed that the homogenous method can effectively control the experimental error of inundation effect,which is less than 50% of the error of CHTC,and less than 30% of the error of the inundation effect gained by routine method.The new test facility built for the homogenous method is excellent in obtaining the accurate inundation effect of film condensation on HTB.All the result is a foundation of the theoretical development of the FCHT on HTB.
