The hallmark of development in the Yangtze River Delta(YRD) of East China has been sprawling urbanization. However, air pollution is a significant problem in these urban areas. In this paper, we investigated and analy...The hallmark of development in the Yangtze River Delta(YRD) of East China has been sprawling urbanization. However, air pollution is a significant problem in these urban areas. In this paper, we investigated and analyzed the air pollution index(API) in four cities(Shanghai, Nanjing, Hangzhou and Ningbo) in the YRD from 2001 to 2012. We attempted to empirically examine the relationship between meteorological factors and air quality in the urban areas of the YRD. According to the monitoring data, the API in Shanghai, Nanjing, Hangzhou slightly declined and that in Ningbo increased over the study period. We analyzed the inter-annual, seasonal, and monthly variations of API, from which we found that the air quality had different temporal changes in the four cities. It was indicated that air quality was poor in winter and spring and best in summer. Furthermore, different weather conditions affected air quality level. The wind direction was considered as an important and influential factor to air pollution, which has an impact on the accumulating or cleaning processes of pollutants. The air quality was influenced by the different wind directions that varied with seasons and cities.展开更多
This paper focuses on the drying characteristic of anchovy fish （Anchovia engraulidae）. It is necessary to understand the drying behavior, quality of the products and time required to optimize the energy consumption...This paper focuses on the drying characteristic of anchovy fish （Anchovia engraulidae）. It is necessary to understand the drying behavior, quality of the products and time required to optimize the energy consumption of the process. The optimum velocity and temperature of drying air for good quality dried anchovy fish was determined. In average, the fish are 7 cm in length and 3.0-3.5 g in mass. Although some research on fish drying has been done, the study of drying of anchovy fish and its characteristic has not been well reported. The fish to be dried were arranged on 15 × 15 cm2 tray in the drying chamber of 17 × 30 cm2. The hot air of 40 -70 ℃ was delivered parallel to the tray with the velocity of 0.6 and 0.9 m s-1. It is found that thermal conductivity （k） and specific heat （cp） of anchovy fish are function of the moisture content （MC）. The higher moisture content results in higher thermal conductivity and specific heat. Critical water content is also found in this experiment as well as the optimum drying condition. Drying rate period of anchovy fish will change from the constant drying rate period to the falling drying rate period when critical moisture content is about 48.8%-50.3% （wet basis）. At these experiments, there is no case-hardening, even at temperature of 70 ℃. To achieve the optimum result, the drying process should be implemented in three steps, drying process at 70 ℃ for 150 min followed by drying at 50℃ for 100 min, and finally drying at 40℃ till achieving equilibrium moisture content. This research will contribute to improvement of drying method to achieve good quality of dried fish.展开更多
Shuttlecock used for badminton is light in mass so that its flight locus is strongly influenced by air. The highest launching velocity of the shuttlecock by professional badminton players exceeds speeds of over 83.3 m...Shuttlecock used for badminton is light in mass so that its flight locus is strongly influenced by air. The highest launching velocity of the shuttlecock by professional badminton players exceeds speeds of over 83.3 m/s （300 km/hr）. In this study, a new badminton server machine was developed. The badminton machine can launch the shuttlecocks at wide range of speeds up to 52.8 m/s （190 km/hr） and with many shot types such as smash, clear and so on, which are easily achieved. The finite element models of a shuttlecock with feathers and the badminton machine were made, and the launching simulations of the shuttlecock were tried. The roller with a large diameter attained a higher speed of the shuttlecock than the small rollers for all kinds of launching conditions. The taper angles of the roller edge and the insert height of the shuttlecock relative to the roller surface were optimized for attaining the maximum shuttle speed by the response surface approach. After the optimization, the performance of the badminton machine had been improved about 7% as the shuttle speeds increase and the stress causing the shuttle deterioration decreased.展开更多
基金Under the auspices of Special Research Fund of the Ministry of Land and Resources for the Non-Profit Sector(No201411014-03)National Key Technology Research and Development Program of China(No.2012BAH28B04)
文摘The hallmark of development in the Yangtze River Delta(YRD) of East China has been sprawling urbanization. However, air pollution is a significant problem in these urban areas. In this paper, we investigated and analyzed the air pollution index(API) in four cities(Shanghai, Nanjing, Hangzhou and Ningbo) in the YRD from 2001 to 2012. We attempted to empirically examine the relationship between meteorological factors and air quality in the urban areas of the YRD. According to the monitoring data, the API in Shanghai, Nanjing, Hangzhou slightly declined and that in Ningbo increased over the study period. We analyzed the inter-annual, seasonal, and monthly variations of API, from which we found that the air quality had different temporal changes in the four cities. It was indicated that air quality was poor in winter and spring and best in summer. Furthermore, different weather conditions affected air quality level. The wind direction was considered as an important and influential factor to air pollution, which has an impact on the accumulating or cleaning processes of pollutants. The air quality was influenced by the different wind directions that varied with seasons and cities.
文摘This paper focuses on the drying characteristic of anchovy fish （Anchovia engraulidae）. It is necessary to understand the drying behavior, quality of the products and time required to optimize the energy consumption of the process. The optimum velocity and temperature of drying air for good quality dried anchovy fish was determined. In average, the fish are 7 cm in length and 3.0-3.5 g in mass. Although some research on fish drying has been done, the study of drying of anchovy fish and its characteristic has not been well reported. The fish to be dried were arranged on 15 × 15 cm2 tray in the drying chamber of 17 × 30 cm2. The hot air of 40 -70 ℃ was delivered parallel to the tray with the velocity of 0.6 and 0.9 m s-1. It is found that thermal conductivity （k） and specific heat （cp） of anchovy fish are function of the moisture content （MC）. The higher moisture content results in higher thermal conductivity and specific heat. Critical water content is also found in this experiment as well as the optimum drying condition. Drying rate period of anchovy fish will change from the constant drying rate period to the falling drying rate period when critical moisture content is about 48.8%-50.3% （wet basis）. At these experiments, there is no case-hardening, even at temperature of 70 ℃. To achieve the optimum result, the drying process should be implemented in three steps, drying process at 70 ℃ for 150 min followed by drying at 50℃ for 100 min, and finally drying at 40℃ till achieving equilibrium moisture content. This research will contribute to improvement of drying method to achieve good quality of dried fish.
文摘Shuttlecock used for badminton is light in mass so that its flight locus is strongly influenced by air. The highest launching velocity of the shuttlecock by professional badminton players exceeds speeds of over 83.3 m/s （300 km/hr）. In this study, a new badminton server machine was developed. The badminton machine can launch the shuttlecocks at wide range of speeds up to 52.8 m/s （190 km/hr） and with many shot types such as smash, clear and so on, which are easily achieved. The finite element models of a shuttlecock with feathers and the badminton machine were made, and the launching simulations of the shuttlecock were tried. The roller with a large diameter attained a higher speed of the shuttlecock than the small rollers for all kinds of launching conditions. The taper angles of the roller edge and the insert height of the shuttlecock relative to the roller surface were optimized for attaining the maximum shuttle speed by the response surface approach. After the optimization, the performance of the badminton machine had been improved about 7% as the shuttle speeds increase and the stress causing the shuttle deterioration decreased.
