The system of mixture of single lane and double lane is studied by a cellular automata model, which is developed by us based on the Nagel and Schreckenberg＇s models. We justify that the model can reach a stable state...The system of mixture of single lane and double lane is studied by a cellular automata model, which is developed by us based on the Nagel and Schreckenberg＇s models. We justify that the model can reach a stable states quickly. The density distributions of the stable state is presented for several cases, which illustrate the manner of the congestion. The relationship between the outflow rate and the total number of vehicles and that between the outflow rate and the density just before the bottleneck are both given. Comparing with the relationship that occurring in the granular flow, we conclude that the transition from the free traffic flow to the congested traffic flow can also be attributed to the abrupt variation through unstable flow state, which can naturally explain the discontinuities and the complex time variation behavior observed in the traffic flow experiments.展开更多
Aggressive behavior can be an important factor in determining how animals use and divide space and resources. Previous studies have shown that aggression in fishes can be influenced by a variety of factors, including ...Aggressive behavior can be an important factor in determining how animals use and divide space and resources. Previous studies have shown that aggression in fishes can be influenced by a variety of factors, including water temperature and resource levels. In this study, we tested if the amount of habitat structure in the environment affected aggression levels in female convict cichlids Archocentrus nigrofasciatus. We performed a laboratory experiment in which we placed female convict cichlids into an aquarium with low or high amounts of habitat structure and monitored the dominant female＇s behavior toward the subordinate female. Aggressive behavior in convict cichlids primarily consists of chases and bites. We found that the total time the dominant female spent chasing the subordinate female was greater when there was a low amount of habitat structure as compared to when there was a high amount of habitat structure. We also found that both the average duration of a chasing bout and the number of bites directed at the subordinate fish increased when there was a low amount of structure, but the number of chases did not. These results indicate that increased habitat structural complexity decreases aggressive behavior in convict cichlids [Current Zoology 56 （1）： 52-56, 2010].展开更多
In Africa, donkeys have significant contribution in traction operation, but there is little research related to workload and their welfare. The objective of this work was to examine the effect of various loads on donk...In Africa, donkeys have significant contribution in traction operation, but there is little research related to workload and their welfare. The objective of this work was to examine the effect of various loads on donkeys＇ physiological and behavioural responses to evaluate welfare. Donkeys weighing of 132-172 kg （159 ± 11 kg） and totally 20 were used for the experiment. The experimental design included two wheeled cart × seven load class （an increment of 100 kg） with five repetitions each, and the travelled distance was 2 km. Travelled time, behavioural occurrences and physiological responses were recorded. Statistical analysis was conducted using SAS （version 9.4） software programme. When loads were 500-700 kg, heavy and rapid panting and falling down occurred frequently. When loads increased successively and reached 500, 600 and 700 kg, speed started declining from 3.68 km/hto 3.5, 2.94 and 2.54 krn/h, respectively, indicating that speed and applied loads are inversely correlated （P 〈 0.001）. Heart rate was 129 ± 11 bpm at 700 kg, and in respect to resting state, donkeys＇ heart rate elevated by a factor of up to 3. As the load exceeded 400 kg, the speed declined significantly, and behavioural occurrences like heavy panting and falling down confirmed this. This leads to the conclusion that donkeys could pull about 2.7 times of their live weight. But if they have continuous and long working hours （about 6 h）, it is recommended to keep load of two wheeled cart about double of donkeys live weight so as to safe guard donkeys＇ welfare.展开更多
This work explores the feasibility of a novel predictive control strategy on a power factor correction system. The proposed control strategy allows a significant reduction of the power losses respect to a classical pr...This work explores the feasibility of a novel predictive control strategy on a power factor correction system. The proposed control strategy allows a significant reduction of the power losses respect to a classical predictive control strategy working with a fixed execution time Ts. The proposed control strategy operates with a variable execution time T~, and it has been implemented using a low cost hardware platform based on TI~ TMS320F2812 DSP. The chosen platform is capable to execute a control strategy code with a variable execution time T,. This operation can be performed by setting in proper manner, the timer registers of one of two event manager A/B blocks present on the mentioned DSP （digital signal processor）.展开更多
Biomass in the form of nutshell, hay of catkin, wheat straw and linseed residue in particles have been pyrolyzed in laboratory scale fixed bed reactor which yielded liquid oil, solid char and gas. The variation of oil...Biomass in the form of nutshell, hay of catkin, wheat straw and linseed residue in particles have been pyrolyzed in laboratory scale fixed bed reactor which yielded liquid oil, solid char and gas. The variation of oil yield for different biomass feedstock with reactor bed temperature and feed size is presented in this paper. A maximum liquid yield of 55 wt% of dry feedstock is obtained at an optimum temperature of 500℃ for a feed size of 300-600μm with a running time of 55 min for nutshell as the feedstock while the minimum liquid oil yield is found to be 30 wt% of feedstock at an optimum temperature of 400℃ for a feed size of 2.36 mm with a running time of 65 min for linseed residue as the feedstock. A comparison on the product yields is highlighted in this study. The pyrolysis liquid products are characterized and compared for some of the fuel properties like HHV （higher heating value）, viscosity, density and specific gravity.展开更多
The relation between the implementation time of small reactor and its market was studied if small reactor could be implemented to be utilized as a base load operation. If the small reactors with 100 or 50 MWe could be...The relation between the implementation time of small reactor and its market was studied if small reactor could be implemented to be utilized as a base load operation. If the small reactors with 100 or 50 MWe could be implemented from 2020, the potential countries could be selected from the view point of the estimated total electricity consumption in 2020 and the stability of the electrical grid system. The commercialization of small reactors should be best done early because the market for these power units as a base load operation might be reduced due to the increase of the electricity consumption in the future after 2020. The implementation program of small reactors for the district heating and electricity supply in Mongolia, which is one of the countries having the interests in small reactor, was investigated and the future implementation plan was proposed too. In order to reduce the air pollution by coal fired heating system, there is an urgent need to start the discussion for the utilization of nuclear district heating reactor in Ulaanbaatar.展开更多
Recently, Sandia Laboratories developed a neutron scatter camera to detect special nuclear materials. This camera exhibits the following advantages: high efficiency, direction discrimination, neutron-gamma discriminat...Recently, Sandia Laboratories developed a neutron scatter camera to detect special nuclear materials. This camera exhibits the following advantages: high efficiency, direction discrimination, neutron-gamma discrimination ability, and wide field of view. However, using the direct projection method, the angular resolution of this camera is limited by uncertainties in the energies estimated from pulse height and time of flight measurements. In this study, we established an eight-element neutron scatter camera and conducted the experiment with a ^(252)Cf neutron source. The results show that it has an angular resolution better than 8°(1s) and a detection efficiency of approximately 2.6′10-4. Using maximum likelihood expectation maximization method, the image artifact was eliminated, and the angular resolution was improved. We proposed an average scattering angle method to estimate the scattering energy of neutrons and Compton gamma rays. As such, we can obtain a recognizable image and energy spectrum of the source with some degradation of energy and image resolutions. Finally, a newly measured light response function based on the MPD^(-4) device was used for image reconstruction. Although we did not obtain a better result than that of the standard light response function, we have observed the effects of light response function on image reconstruction.展开更多
基金supported by National Natural Science Foundation of China under Grant Nos. 10674157 and 10875166
文摘The system of mixture of single lane and double lane is studied by a cellular automata model, which is developed by us based on the Nagel and Schreckenberg＇s models. We justify that the model can reach a stable states quickly. The density distributions of the stable state is presented for several cases, which illustrate the manner of the congestion. The relationship between the outflow rate and the total number of vehicles and that between the outflow rate and the density just before the bottleneck are both given. Comparing with the relationship that occurring in the granular flow, we conclude that the transition from the free traffic flow to the congested traffic flow can also be attributed to the abrupt variation through unstable flow state, which can naturally explain the discontinuities and the complex time variation behavior observed in the traffic flow experiments.
基金Acknowledgements We thank Samantha Hilber for valuable comments on the manuscriPt. RMC thanks G.W. Barlow for countless discussions about behavior and for his unbounded enthusiasm for fishes.
文摘Aggressive behavior can be an important factor in determining how animals use and divide space and resources. Previous studies have shown that aggression in fishes can be influenced by a variety of factors, including water temperature and resource levels. In this study, we tested if the amount of habitat structure in the environment affected aggression levels in female convict cichlids Archocentrus nigrofasciatus. We performed a laboratory experiment in which we placed female convict cichlids into an aquarium with low or high amounts of habitat structure and monitored the dominant female＇s behavior toward the subordinate female. Aggressive behavior in convict cichlids primarily consists of chases and bites. We found that the total time the dominant female spent chasing the subordinate female was greater when there was a low amount of habitat structure as compared to when there was a high amount of habitat structure. We also found that both the average duration of a chasing bout and the number of bites directed at the subordinate fish increased when there was a low amount of structure, but the number of chases did not. These results indicate that increased habitat structural complexity decreases aggressive behavior in convict cichlids [Current Zoology 56 （1）： 52-56, 2010].
文摘In Africa, donkeys have significant contribution in traction operation, but there is little research related to workload and their welfare. The objective of this work was to examine the effect of various loads on donkeys＇ physiological and behavioural responses to evaluate welfare. Donkeys weighing of 132-172 kg （159 ± 11 kg） and totally 20 were used for the experiment. The experimental design included two wheeled cart × seven load class （an increment of 100 kg） with five repetitions each, and the travelled distance was 2 km. Travelled time, behavioural occurrences and physiological responses were recorded. Statistical analysis was conducted using SAS （version 9.4） software programme. When loads were 500-700 kg, heavy and rapid panting and falling down occurred frequently. When loads increased successively and reached 500, 600 and 700 kg, speed started declining from 3.68 km/hto 3.5, 2.94 and 2.54 krn/h, respectively, indicating that speed and applied loads are inversely correlated （P 〈 0.001）. Heart rate was 129 ± 11 bpm at 700 kg, and in respect to resting state, donkeys＇ heart rate elevated by a factor of up to 3. As the load exceeded 400 kg, the speed declined significantly, and behavioural occurrences like heavy panting and falling down confirmed this. This leads to the conclusion that donkeys could pull about 2.7 times of their live weight. But if they have continuous and long working hours （about 6 h）, it is recommended to keep load of two wheeled cart about double of donkeys live weight so as to safe guard donkeys＇ welfare.
文摘This work explores the feasibility of a novel predictive control strategy on a power factor correction system. The proposed control strategy allows a significant reduction of the power losses respect to a classical predictive control strategy working with a fixed execution time Ts. The proposed control strategy operates with a variable execution time T~, and it has been implemented using a low cost hardware platform based on TI~ TMS320F2812 DSP. The chosen platform is capable to execute a control strategy code with a variable execution time T,. This operation can be performed by setting in proper manner, the timer registers of one of two event manager A/B blocks present on the mentioned DSP （digital signal processor）.
文摘Biomass in the form of nutshell, hay of catkin, wheat straw and linseed residue in particles have been pyrolyzed in laboratory scale fixed bed reactor which yielded liquid oil, solid char and gas. The variation of oil yield for different biomass feedstock with reactor bed temperature and feed size is presented in this paper. A maximum liquid yield of 55 wt% of dry feedstock is obtained at an optimum temperature of 500℃ for a feed size of 300-600μm with a running time of 55 min for nutshell as the feedstock while the minimum liquid oil yield is found to be 30 wt% of feedstock at an optimum temperature of 400℃ for a feed size of 2.36 mm with a running time of 65 min for linseed residue as the feedstock. A comparison on the product yields is highlighted in this study. The pyrolysis liquid products are characterized and compared for some of the fuel properties like HHV （higher heating value）, viscosity, density and specific gravity.
文摘The relation between the implementation time of small reactor and its market was studied if small reactor could be implemented to be utilized as a base load operation. If the small reactors with 100 or 50 MWe could be implemented from 2020, the potential countries could be selected from the view point of the estimated total electricity consumption in 2020 and the stability of the electrical grid system. The commercialization of small reactors should be best done early because the market for these power units as a base load operation might be reduced due to the increase of the electricity consumption in the future after 2020. The implementation program of small reactors for the district heating and electricity supply in Mongolia, which is one of the countries having the interests in small reactor, was investigated and the future implementation plan was proposed too. In order to reduce the air pollution by coal fired heating system, there is an urgent need to start the discussion for the utilization of nuclear district heating reactor in Ulaanbaatar.
基金supported by the National Natural Science Fundation of China(Grant Nos.1110510611375144&11275153)
文摘Recently, Sandia Laboratories developed a neutron scatter camera to detect special nuclear materials. This camera exhibits the following advantages: high efficiency, direction discrimination, neutron-gamma discrimination ability, and wide field of view. However, using the direct projection method, the angular resolution of this camera is limited by uncertainties in the energies estimated from pulse height and time of flight measurements. In this study, we established an eight-element neutron scatter camera and conducted the experiment with a ^(252)Cf neutron source. The results show that it has an angular resolution better than 8°(1s) and a detection efficiency of approximately 2.6′10-4. Using maximum likelihood expectation maximization method, the image artifact was eliminated, and the angular resolution was improved. We proposed an average scattering angle method to estimate the scattering energy of neutrons and Compton gamma rays. As such, we can obtain a recognizable image and energy spectrum of the source with some degradation of energy and image resolutions. Finally, a newly measured light response function based on the MPD^(-4) device was used for image reconstruction. Although we did not obtain a better result than that of the standard light response function, we have observed the effects of light response function on image reconstruction.
