BaFe12O19 fibers was prepared via an aqueous sol-gel process using Fe（OH）（HCOO）2 synthesized in laboratory and Ba（CH3COO）2 as the original materials and citrate as the chelate. The rheological behaviour of spinn...BaFe12O19 fibers was prepared via an aqueous sol-gel process using Fe（OH）（HCOO）2 synthesized in laboratory and Ba（CH3COO）2 as the original materials and citrate as the chelate. The rheological behaviour of spinnable sol was characterized on rheometer, and the development of gel fibers to barium ferrite fibers was studied by IR, TG and XRD. Morphology observation of the fibers was given on SEM, and the diameter of the obtained fibers was between 5 and 10 um corresponding to different additives. The additives affected the surface tension of the precursor sol which had close relation to the microstructure of fibers. Sucrose and hydroxyethylic cellulose could improve the surface tension while diethanolamine and hexadecylamine reduce that of the decylamine as an additive, well-structured BaFe12O19 precursor sol. And using diethanolamine or hexafibers could be obtained.展开更多
The reliability and maintainability of electrical system of drum shearer at Parvade. 1 Coal Mine in central Iran was analyzed. The maintenance and failure data were collected during 19 months of shearer operation. Acc...The reliability and maintainability of electrical system of drum shearer at Parvade. 1 Coal Mine in central Iran was analyzed. The maintenance and failure data were collected during 19 months of shearer operation. According to trend and serial correlation tests, the data were independent and identically distributed （iid） and therefore the statistical techniques were used for modeling. The data analysis show that the time between failures （TBF） and time to repair （TTR） data obey the lognormal and Weibull 3 parameters distribution respectively. Reliability-based preventive maintenance time intervals for electrical system of the drum shearer were calculated with regard to reliability plot. The reliability-based maintenance intervals for 90%, 80%, 70% and 50% reliability level are respectively 9.91, 17.96, 27.56 and 56.1 h. Also the calculations show that time to repair （TTR） of this system varies in range 0.17-4 h with 1.002 h as mean time to repair （MTTR）. There is a 80% chance that the electrical system of shearer of Parvade. 1 mine repair will be accomplished within 1.45 h.展开更多
A 3-month feeding experiment was conducted in an in-door seawater system to investigate the effect of dietary vitamin E （Ve） on the sperm quality of turbot （Scophthalmus maximus）. D-α-tocopherol acetate was suppl...A 3-month feeding experiment was conducted in an in-door seawater system to investigate the effect of dietary vitamin E （Ve） on the sperm quality of turbot （Scophthalmus maximus）. D-α-tocopherol acetate was supplemented to the basal （control） diet （65.14 mg kg-l Ve） to obtain low and high levels of dietary Ve （244.60 mgkg-1, LVe; 721.60 mg kg-1, HVe）. Compared with the con- trol, sperm concentration was significantly increased in Ve-supplemented groups （LVe and HVe）; while relative sperm volume and testis-somatic index were significantly increased in group HVe only. Sperm motility duration was significantly longer in group HVe than in the control, but no significant difference was observed in percent motility among groups. Sperm size, the uniformity of mito- chondrial size, and the integrity of mitochondria cristae and plasma membrane were improved by dietary Ve, especially in HVe. The content of Ve in testis and liver as well as polyunsaturated fatty acids in sperm increased with dietary Ve. These results suggested that dietary Ve, especially at the high level （721.60 mg kgl）, significantly improved sperm concentration and motility duration and main- tained normal sperm morphology of turbot.Abstract A 3-month feeding experiment was conducted in an in-door seawater system to investigate the effect of dietary vitamin E （Ve） on the sperm quality of turbot （Scophthalmus maximus）. D-α-tocopherol acetate was supplemented to the basal （control） diet （65.14 mg kg-l Ve） to obtain low and high levels of dietary Ve （244.60 mgkg-1, LVe; 721.60 mg kg-1, HVe）. Compared with the con- trol, sperm concentration was significantly increased in Ve-supplemented groups （LVe and HVe）; while relative sperm volume and testis-somatic index were significantly increased in group HVe only. Sperm motility duration was significantly longer in group HVe than in the control, but no significant difference was observed in percent motility among groups. Sperm size, the uniformity of mito- chondrial size, and the integrity of mitochondria cristae and plasma membrane were improved by dietary Ve, especially in HVe. The content of Ve in testis and liver as well as polyunsaturated fatty acids in sperm increased with dietary Ve. These results suggested that dietary Ve, especially at the high level （721.60 mg kgl）, significantly improved sperm concentration and motility duration and main- tained normal sperm morphology of turbot.展开更多
Passive strategies for acclimatization of buildings have been studied by several authors in many countries, especially the evaporative and radiant cooling techniques. Fiber cement tiles are very common in popular cons...Passive strategies for acclimatization of buildings have been studied by several authors in many countries, especially the evaporative and radiant cooling techniques. Fiber cement tiles are very common in popular constructions due to their low cost. However, they have over twice of the value thermal transmittance indicated to this bioclimatic zone according to Brazilian guidelines. The objective is to present an alternative to reduce high temperatures on fiber cement tiles. In this paper, the monitoring of passive cooling of roofing during the spring season in a city with subtropical climate is described. Single and combined reflective and evaporative cooling systems were studied in different environmental conditions. Internal surface temperatures of tiles were monitored together with weather variables. Results show a decrease of about 6 ℃, 9 ℃, 10 ℃ and 11 ℃ as compared to the original tiles according to environment conditions and the combined passive cooling techniques. These results allow for the conclusion that the use of passive cooling techniques opens up new possibilities to attenuate the internal surface temperatures of tiles and to consequently decrease the roofing solar heat gain into buildings, thus, providing less air cooling energy consumption.展开更多
A series of water absorption tests on dried soft rock have been conducted by the intelligent testing system for water absorption tests in deep soft rock, including tests of water absorption with and without pres- sure...A series of water absorption tests on dried soft rock have been conducted by the intelligent testing system for water absorption tests in deep soft rock, including tests of water absorption with and without pres- sure. The results show that the water absorbing capacity of rock with a certain pressure is larger than that of rock without pressure： however, the relationship between the water absorbing percentage and the time can be expressed by w（t） = a（l - e^-bt）. In hi-logarithmic coordinates, the hydrophilic relationship with time in tests with pressure could be characterized by linearity, while they present concave or convex in tests without pressure. Based on the hypothesis that each influential factor is irrelevant and they have a linear correlation with the water absorbing capacity, we calculated the weight coefficient of each factor according to experimental results under different conditions. The calculations demonstrate that the effec- tive porosity, content of smectite and kaolinite are all positively correlated with the water absorption capacity of rock; meanwhile, the fractal dimension of the effective pores presents a negative correlation with the water absorption capacity of rock. The water absorption capacity with pressure increases with increasing illite, chlorite and chlorite/smectite formation and a decrease in illite/smectite formation and the fractal dimension of the effective pores, while it is opposite in tests without pressure. The weight coefficient of smectite is smallest among positive factors, and the fractal dimension of the effective pores is the smallest amongst the negative factors.展开更多
In the last decades, there is a lot of discussion in many scientific fields, about the high importance of water as a basic element for the existence and the maintenance of life, aiming to the right and proper usage of...In the last decades, there is a lot of discussion in many scientific fields, about the high importance of water as a basic element for the existence and the maintenance of life, aiming to the right and proper usage of water in our everyday basic water-needs due to its limited resources and the growing demand. This research deals with simple ways and technological systems applicable in urban residential buildings for the better management of domestic fresh water, as far as its maintenance and sustainability. Main aim of the survey is the effective minimization of urban daily water usage. All measurements of water quantities have estimated in the imperial gallon （1 gallon = 4.546 liter）, and in liter （1 liter = 0.2 gallon）.展开更多
The fractal characteristics of drainage in the ten kongduis of the upper Yellow River were obtained using the box counting dimension, and the evolution stages of the watershed topography were defined by different rang...The fractal characteristics of drainage in the ten kongduis of the upper Yellow River were obtained using the box counting dimension, and the evolution stages of the watershed topography were defined by different ranges of the fractal dimensions of river networks（D_g）. The results show that the fractal scaleless range of the Maobula River is 20–370 m based on a combination of artificial judgment, correlation coefficient test and fitting error. Other kongduis show good fractal characteristics in this fractal scaleless range as well. The box counting dimension can be used as a quantitative index of watershed topography fractal characteristics. The fractal dimension of stream networks is independent of the threshold contributing area used for extracting the drainage networks from the DEM. The values of D_g in the upper ten kongduis are in the range of 1.08-1.14. Both the runoff yield and the sediment yield are positively and linearly related with D_g. The positive relation between the sediment yield and D_g reflects the effect of landform features on sediment yield in the young and/or mature stages of landform evolution of the study area. By revising the critical value of D_g, the value of D_g of the basin in the young evolution stage is less than 1.06, while it is more than 1.06 for the basin in mature or old evolution stage. The upper ten kongduis are in the mature stage of landform evolution.展开更多
During the long-term construction and development process of eliminating water disasters and promoting water conservancy in traditional settlements,a set of mature strategies that have simple ecological wisdom in wate...During the long-term construction and development process of eliminating water disasters and promoting water conservancy in traditional settlements,a set of mature strategies that have simple ecological wisdom in water layout have been formed by adapting to the natural water environment and utilizing the regional water system.This study conducted a qualitative and quantitative analysis of the water layout strategies and their effects on Liukeng Village from three aspects:deciphering the water systematic pattern,calculating the spatial characteristics and quantifying the water environment,to explore the technical assistance and potential of water layout research in traditional rural settlements.The results indicated that Liukeng has an unambiguously systematic water layout pattern of source diversion,middle drainage and end purification of the water.Through 3D point cloud computing,it was shown that the site selection made accurate use of micro-topography and adopted the strategy of a multi-source water management.It formed an organic water system pattern,which provided sufficient water sources for all kinds of needs of Liukeng Village.The Dragon Lake in Liukeng held 83.0%of the precipitation,and the vegetation area accounted for 34.7%of the total area of Liukeng,which had high surface permeability and good middle drainage effects.Water detection showed that the Dragon Lake provided good water quality and purification.The purposes of this study are to fill the gap in previous non-quantitative research on water layout in traditional rural settlements,excavate the hidden information and value of settlements,and deepen our understanding of the ecological wisdom of the overall planning,layout and construction of water conservancy in traditional rural settlements.This knowledge can assist the win-win situation of water conservancy cultural heritage protection and modern utilization.It also provides useful inspiration and reference for properly dealing with the problems of rain and flooding,realizing the sustainability of water resources,and protecting the ecological environment in the process of the development and construction of village settlements in China.展开更多
基金Supported by National Natural Science Foundation of China(No.50506020)Natural Science Foundation of Tianjin(No.043605211)Young Teacher Foundation of Tianjin University(No.5110103)
文摘BaFe12O19 fibers was prepared via an aqueous sol-gel process using Fe（OH）（HCOO）2 synthesized in laboratory and Ba（CH3COO）2 as the original materials and citrate as the chelate. The rheological behaviour of spinnable sol was characterized on rheometer, and the development of gel fibers to barium ferrite fibers was studied by IR, TG and XRD. Morphology observation of the fibers was given on SEM, and the diameter of the obtained fibers was between 5 and 10 um corresponding to different additives. The additives affected the surface tension of the precursor sol which had close relation to the microstructure of fibers. Sucrose and hydroxyethylic cellulose could improve the surface tension while diethanolamine and hexadecylamine reduce that of the decylamine as an additive, well-structured BaFe12O19 precursor sol. And using diethanolamine or hexafibers could be obtained.
文摘The reliability and maintainability of electrical system of drum shearer at Parvade. 1 Coal Mine in central Iran was analyzed. The maintenance and failure data were collected during 19 months of shearer operation. According to trend and serial correlation tests, the data were independent and identically distributed （iid） and therefore the statistical techniques were used for modeling. The data analysis show that the time between failures （TBF） and time to repair （TTR） data obey the lognormal and Weibull 3 parameters distribution respectively. Reliability-based preventive maintenance time intervals for electrical system of the drum shearer were calculated with regard to reliability plot. The reliability-based maintenance intervals for 90%, 80%, 70% and 50% reliability level are respectively 9.91, 17.96, 27.56 and 56.1 h. Also the calculations show that time to repair （TTR） of this system varies in range 0.17-4 h with 1.002 h as mean time to repair （MTTR）. There is a 80% chance that the electrical system of shearer of Parvade. 1 mine repair will be accomplished within 1.45 h.
基金financially supported by a grant from the Modern Agro-Industry Technology Research System of China(CARS-50-G08)
文摘A 3-month feeding experiment was conducted in an in-door seawater system to investigate the effect of dietary vitamin E （Ve） on the sperm quality of turbot （Scophthalmus maximus）. D-α-tocopherol acetate was supplemented to the basal （control） diet （65.14 mg kg-l Ve） to obtain low and high levels of dietary Ve （244.60 mgkg-1, LVe; 721.60 mg kg-1, HVe）. Compared with the con- trol, sperm concentration was significantly increased in Ve-supplemented groups （LVe and HVe）; while relative sperm volume and testis-somatic index were significantly increased in group HVe only. Sperm motility duration was significantly longer in group HVe than in the control, but no significant difference was observed in percent motility among groups. Sperm size, the uniformity of mito- chondrial size, and the integrity of mitochondria cristae and plasma membrane were improved by dietary Ve, especially in HVe. The content of Ve in testis and liver as well as polyunsaturated fatty acids in sperm increased with dietary Ve. These results suggested that dietary Ve, especially at the high level （721.60 mg kgl）, significantly improved sperm concentration and motility duration and main- tained normal sperm morphology of turbot.Abstract A 3-month feeding experiment was conducted in an in-door seawater system to investigate the effect of dietary vitamin E （Ve） on the sperm quality of turbot （Scophthalmus maximus）. D-α-tocopherol acetate was supplemented to the basal （control） diet （65.14 mg kg-l Ve） to obtain low and high levels of dietary Ve （244.60 mgkg-1, LVe; 721.60 mg kg-1, HVe）. Compared with the con- trol, sperm concentration was significantly increased in Ve-supplemented groups （LVe and HVe）; while relative sperm volume and testis-somatic index were significantly increased in group HVe only. Sperm motility duration was significantly longer in group HVe than in the control, but no significant difference was observed in percent motility among groups. Sperm size, the uniformity of mito- chondrial size, and the integrity of mitochondria cristae and plasma membrane were improved by dietary Ve, especially in HVe. The content of Ve in testis and liver as well as polyunsaturated fatty acids in sperm increased with dietary Ve. These results suggested that dietary Ve, especially at the high level （721.60 mg kgl）, significantly improved sperm concentration and motility duration and main- tained normal sperm morphology of turbot.
文摘Passive strategies for acclimatization of buildings have been studied by several authors in many countries, especially the evaporative and radiant cooling techniques. Fiber cement tiles are very common in popular constructions due to their low cost. However, they have over twice of the value thermal transmittance indicated to this bioclimatic zone according to Brazilian guidelines. The objective is to present an alternative to reduce high temperatures on fiber cement tiles. In this paper, the monitoring of passive cooling of roofing during the spring season in a city with subtropical climate is described. Single and combined reflective and evaporative cooling systems were studied in different environmental conditions. Internal surface temperatures of tiles were monitored together with weather variables. Results show a decrease of about 6 ℃, 9 ℃, 10 ℃ and 11 ℃ as compared to the original tiles according to environment conditions and the combined passive cooling techniques. These results allow for the conclusion that the use of passive cooling techniques opens up new possibilities to attenuate the internal surface temperatures of tiles and to consequently decrease the roofing solar heat gain into buildings, thus, providing less air cooling energy consumption.
文摘A series of water absorption tests on dried soft rock have been conducted by the intelligent testing system for water absorption tests in deep soft rock, including tests of water absorption with and without pres- sure. The results show that the water absorbing capacity of rock with a certain pressure is larger than that of rock without pressure： however, the relationship between the water absorbing percentage and the time can be expressed by w（t） = a（l - e^-bt）. In hi-logarithmic coordinates, the hydrophilic relationship with time in tests with pressure could be characterized by linearity, while they present concave or convex in tests without pressure. Based on the hypothesis that each influential factor is irrelevant and they have a linear correlation with the water absorbing capacity, we calculated the weight coefficient of each factor according to experimental results under different conditions. The calculations demonstrate that the effec- tive porosity, content of smectite and kaolinite are all positively correlated with the water absorption capacity of rock; meanwhile, the fractal dimension of the effective pores presents a negative correlation with the water absorption capacity of rock. The water absorption capacity with pressure increases with increasing illite, chlorite and chlorite/smectite formation and a decrease in illite/smectite formation and the fractal dimension of the effective pores, while it is opposite in tests without pressure. The weight coefficient of smectite is smallest among positive factors, and the fractal dimension of the effective pores is the smallest amongst the negative factors.
文摘In the last decades, there is a lot of discussion in many scientific fields, about the high importance of water as a basic element for the existence and the maintenance of life, aiming to the right and proper usage of water in our everyday basic water-needs due to its limited resources and the growing demand. This research deals with simple ways and technological systems applicable in urban residential buildings for the better management of domestic fresh water, as far as its maintenance and sustainability. Main aim of the survey is the effective minimization of urban daily water usage. All measurements of water quantities have estimated in the imperial gallon （1 gallon = 4.546 liter）, and in liter （1 liter = 0.2 gallon）.
基金National Natural Science Foundation of China(41371036)
文摘The fractal characteristics of drainage in the ten kongduis of the upper Yellow River were obtained using the box counting dimension, and the evolution stages of the watershed topography were defined by different ranges of the fractal dimensions of river networks（D_g）. The results show that the fractal scaleless range of the Maobula River is 20–370 m based on a combination of artificial judgment, correlation coefficient test and fitting error. Other kongduis show good fractal characteristics in this fractal scaleless range as well. The box counting dimension can be used as a quantitative index of watershed topography fractal characteristics. The fractal dimension of stream networks is independent of the threshold contributing area used for extracting the drainage networks from the DEM. The values of D_g in the upper ten kongduis are in the range of 1.08-1.14. Both the runoff yield and the sediment yield are positively and linearly related with D_g. The positive relation between the sediment yield and D_g reflects the effect of landform features on sediment yield in the young and/or mature stages of landform evolution of the study area. By revising the critical value of D_g, the value of D_g of the basin in the young evolution stage is less than 1.06, while it is more than 1.06 for the basin in mature or old evolution stage. The upper ten kongduis are in the mature stage of landform evolution.
基金The National Natural Science Foundation of China(51878439,51878437,51908179)The Project of Key Laboratory of Ministry of Cultureand Tourism(20180508)+1 种基金The Youth Foundation for Humanities and Social Sciences of the Ministry of Education(17YJCZH095)The SocialScience Foundation of Hebei Province(HB19YS036).
文摘During the long-term construction and development process of eliminating water disasters and promoting water conservancy in traditional settlements,a set of mature strategies that have simple ecological wisdom in water layout have been formed by adapting to the natural water environment and utilizing the regional water system.This study conducted a qualitative and quantitative analysis of the water layout strategies and their effects on Liukeng Village from three aspects:deciphering the water systematic pattern,calculating the spatial characteristics and quantifying the water environment,to explore the technical assistance and potential of water layout research in traditional rural settlements.The results indicated that Liukeng has an unambiguously systematic water layout pattern of source diversion,middle drainage and end purification of the water.Through 3D point cloud computing,it was shown that the site selection made accurate use of micro-topography and adopted the strategy of a multi-source water management.It formed an organic water system pattern,which provided sufficient water sources for all kinds of needs of Liukeng Village.The Dragon Lake in Liukeng held 83.0%of the precipitation,and the vegetation area accounted for 34.7%of the total area of Liukeng,which had high surface permeability and good middle drainage effects.Water detection showed that the Dragon Lake provided good water quality and purification.The purposes of this study are to fill the gap in previous non-quantitative research on water layout in traditional rural settlements,excavate the hidden information and value of settlements,and deepen our understanding of the ecological wisdom of the overall planning,layout and construction of water conservancy in traditional rural settlements.This knowledge can assist the win-win situation of water conservancy cultural heritage protection and modern utilization.It also provides useful inspiration and reference for properly dealing with the problems of rain and flooding,realizing the sustainability of water resources,and protecting the ecological environment in the process of the development and construction of village settlements in China.
