To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehol...To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehole.Combining with the engineering geological conditions,we built a numeral model to study the influence rule of the aquifer hydraulic pressure and seepage location of feeding borehole on the amount of seepage with fnite element numerical method.The results show that the nonlinear relationship is presented among the amount of seepage,the seepage location and aquifer hydraulic pressure.The higher the aquifer hydraulic pressure is,the closer the distance between seepage location and aquifer is,and the faster the harmful levels of aquifer will grow.In practice,we calculated the allowable seepage of feeding borehole by the optimum moisture content and natural moisture content of backflling materials,and then determined the protection zone of feeding borehole,so the moisture content of backflling materials can be controlled within the scope of optimum moisture content.展开更多
No or little information on the use fresh(wet)housefly maggots(Musca domestica)in African catfish(Clarias gariepinus)fry feeding.Therefore,this study was conducted to investigate the effect of feeding on fresh(wet)hou...No or little information on the use fresh(wet)housefly maggots(Musca domestica)in African catfish(Clarias gariepinus)fry feeding.Therefore,this study was conducted to investigate the effect of feeding on fresh(wet)housefly maggots with or without artificial diet on water quality,growth performance,survival percentage and feed utilization of African catfish fry under laboratory conditions.Housefly maggots produced from a mixture of poultry droppings and foods wastes,it was used to replace artificial feed at 0,50 and 100% levels.Catfish were fed artificial diet alone(Feed 1),fresh(wet)housefly maggots alone(Feed 2),and 50% fresh housefly maggots with 50% artificial diet(Feed 3)were prepared and tested on triplicate groups of African catfish fry(initial weight of 0.25±0.02 g)for 60 days.Results showed that final weight(g/fish)was significantly(P≤0.05)higher in fish fed on feed 3(6.03±0.08),followed by fish fed feed 2(4.62±0.27),followed by fish fed feed 1(3.15±0.68).Specific growth rate(%/day)was also significantly higher in fish fed on feed 3(5.31±0.10),followed by fish fed feed 2(4.86±0.03),followed by fish fed feed 1(4.18±0.24).The same trend was observed with total weight gain,percentage weight gain,daily growth rate and relative growth rate.Feed intake and protein intake were significantly(P≤0.05)higher in fish fed on feed 3 and fish fed on feed 2,followed by fish fed feed 1.While,feed conversion ratio(FCR)and protein efficiency ratio were not significantly(P>0.05),but the improvement in FCR recorded in catfish fry fed feed 3 and feed 2 under the experimental conditions.Survival percentage was within the range 55-75%,with insignificant differences(P>0.05)among treatments.The water quality parameters such as temperature,pH,dissolved oxygen,total ammonia,nitrite and nitrate were not significantly(P>0.05)between the treatments and were tolerable for Catfish culture.Accordingly,use of the 50% fresh(wet)housefly maggots with 50% artificial diet in African catfish fry feeding had positive effect on growth performance and reduce of the feed cost.展开更多
As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introd...As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introduces a new design of for steam feeding the water pump of an air-cooled unit using the back-pressure steam turbine as the prime motor. Using variable condition analysis on a 600 MW direct air-cooled unit, and with consideration of the effect on the ambient conditions, the feasibility, economy, and adaptability of the design are verified.展开更多
A thermoeconomic optimization analysis is presented yielding simple algebraic formulae for estimating the optimum number of feed water heater and optimal area distribution among the feed water heaters for thermal powe...A thermoeconomic optimization analysis is presented yielding simple algebraic formulae for estimating the optimum number of feed water heater and optimal area distribution among the feed water heaters for thermal power plants. The P1-P2 method is used in the present study, together with the thermoeconomic analyses of feed water heaters.展开更多
Seasonal and sexual variations as well as the effect of dry feed supplement on total drinking water intake and its utilization were observed in mithun （Bosfrontalis） - a semi-wild animal found in North Eastern Hill ...Seasonal and sexual variations as well as the effect of dry feed supplement on total drinking water intake and its utilization were observed in mithun （Bosfrontalis） - a semi-wild animal found in North Eastern Hill Region （NEHR） of India. In a completely randomized design, twelve adult mithuns （B. frontalis） as per their sex and body weight were assigned in two different rearing systems （free grazing and free grazing with dry concentrate feed supplementation）, and ten growing male mithuns as per their body weight assigned in two different levels of dry concentrate feed supplementation （1.o kg and 2.0 kg dry concentrate feeds on green forage based diet） and in two different seasons （summer and winter）. It was observed that the environmental temperature had a significant effect on drinking water intake by mithuns. Drinking water consumption （per unit of body weight） was significantly （P 〈 0.05） higher in summer than in winter. Supplementation of concentrate feed on free grazing animals resulted in increase in water consumption. Total water consumption （drinking as well as performed water） was found to be 15.18 litres per 100 kg body weight by growing mithun. Feed dry matter and digestible nutrient intakes by growing mithun were observed to be increased with the increase of supplementation of dry concentrate feed. Roughage to concentrate ratio did not affect the nutrient digestibility. Mithun calves drank an average of 4.30 litres water for each kg of dry matter intake. Metabolic water was significantly （P〈0.01） increased with the increase of supplementation of concentrate feed whereas water turn over, which depends upon the body weight of the animals, did not differ significantly on offering of lower or higher level of dry feed. Faecal water loss of growing mithun was decreased with the increase in intake of concentrate feed and was estimated to be 33 - 46 % of total water intake. Excretion of water through faeces of mithun was about 3.8 % of body weight. It could, therefore, be inferred that water intake by mithun varied with seasons, rearing systems and dry feed consumption. As far as the water nutrition is concerned, it is needed to give an attention while feeding mithun in summer with dry feed supplementation under semi-intensive system of rearing.展开更多
Feeding rhythm of common carp was investigated from 4℃ to 34℃. The results indicated that there was a diel feeding rhythm for both adult （630-850 g） and youth （61-91 g） at all tested temperatures. There were two...Feeding rhythm of common carp was investigated from 4℃ to 34℃. The results indicated that there was a diel feeding rhythm for both adult （630-850 g） and youth （61-91 g） at all tested temperatures. There were two main activity peaks at 8：00-11：00 a.m. and 19：00-23：00 p.m., during which feeding quantities were 10.68%-32.53% and 16.25%-33.41% of the daily intake, respectively. When water temperature dropped to below 10℃, the feeding peak concentrated at 8：00-11：00 a.m. and 19：00 p.m. to 4：00 a.m. At 6℃, though both adult and youth would still feed, the feeding quantities were only 0.01% and 0.35% of body mass. Daily feeding rate of adult and youth reached 1.21% and 2.63% at 14℃, respectively. Both adult and youth carps reached the maximum daily feeding rate at 28℃, being 2.84% and 12.06% of body mass, respectively. The daily feeding rate of adult and youth reduced suddenly after at 34℃, and the daily feeding rate was only 0.74% and 9.45% of body mass, respectively. There was significant difference in daily feeding rate at different water temperatures （P〈0.05）.展开更多
In view of the fact that cages and bait are not allowed in large water surface aquiculture,1-2 kinds of new green feeds"plankton+microecologics"were developed to solve the problems of yield reduction,slow gr...In view of the fact that cages and bait are not allowed in large water surface aquiculture,1-2 kinds of new green feeds"plankton+microecologics"were developed to solve the problems of yield reduction,slow growth and difficulty in fishing of aquatic organisms caused by extensive mode.The new green feed is ecological,environmentally friendly and residue-free,which not only supplements nutrition but also meets the requirements of environmental protection.展开更多
The study was conducted in Adami Tulu Jidokombolcha(ATJK),Bora,Dodola,Shala and Negele-Arsi districts with objective to assess main cattle feed resources,water sources and housing systems.A pre-tested,semi-structured ...The study was conducted in Adami Tulu Jidokombolcha(ATJK),Bora,Dodola,Shala and Negele-Arsi districts with objective to assess main cattle feed resources,water sources and housing systems.A pre-tested,semi-structured questionnaire was used to conduct survey.About 240 respondents were identified using random sampling techniques.Collected data was analyzed by SPSS statistical software(Ver.24).Study result indicates that household in average had three hectares of land and allocated about two hectares of land for crop cultivation.Most respondents reported that cattle herding is not common during dry season while it is common during wet season.Survey result indicate that natural pasture,weed and maize tiller and stored crop residues are main feed resources in wet season while crop after math,crop residue and fodder trees are main resources during dry season.Brackish,local mineral and common salt are mineral sources for cattle in study areas.Lake,river and boreholes are important water sources in dry season where as ponds and rivers are main water sources during wet season for their cattle.The observed cattle watering frequency is mainly once a day.Housing system practiced in the study areas is mainly Kraal.The information generated from this study on land size per household,cattle herding system,feed resources,mineral sources,water sources,water utilization and housing type can be used as a baseline for any livestock development programs in those and similar areas.展开更多
During the operation of the boiler in thermal power plant, the feed water pump, as the core part, plays an important role that cannot be ignored and is also an important basis for the orderly operation of the boiler. ...During the operation of the boiler in thermal power plant, the feed water pump, as the core part, plays an important role that cannot be ignored and is also an important basis for the orderly operation of the boiler. At present, the boilers of thermal power plants are constantly updated and upgraded to meet the actual operation requirements of thermal power plants, which also puts forward many new requirements for various functions of the boilers to a certain extent. The boiler feed water pump of thermal power plant plays an important role in the stability and safety of the boiler in operation. At present, in the boiler system of thermal power plants, regular maintenance is very important for the boiler feed pump. Only by strengthening the maintenance of the feed pump can the stable operation and reliability of the feed pump be ensured. Therefore, the paper will analyze the problem of boiler feedwater pump failure in thermal power plants and put forward effective maintenance countermeasures, in order to ensure the safe use of boilers in thermal power plants and strengthen the operation efficiency of boiler systems.展开更多
Seawater desalination is a key technological approach to address the global problem of water scarcity.Spacers in water treatment membrane modules play a critical role in the water treatment process.The use of a spacer...Seawater desalination is a key technological approach to address the global problem of water scarcity.Spacers in water treatment membrane modules play a critical role in the water treatment process.The use of a spacer improves fluid dynamics,enhances heat and mass transfer efficiency,and effectively mitigates concentration polarization,reduces fouling risks,and increases the long-term operational stability of the system as a whole.Although numerous novel spacer designs have been proposed in recent years,their large-scale commercialization still faces significant challenges.This review summarizes the critical strategies for improving hydraulic performance,mitigating scaling issues,and enhancing heat and mass transfer performance of spacers.It focuses on structural innovations that aim to optimize spacer performance and meet the diverse demands of various desalination methods.On the basis of a comprehensive analysis of spacer performance in typical application scenarios,it summarizes the limitations of current research,identifies future research directions,and highlights the potential of novel spacer designs to improve desalination efficiency.This review enhances understanding of the role of spacers in desalination systems and offers new research directions for future developments in seawater desalination technology.展开更多
基金funded by the State Key Development Program for Basic Research of China(No.2013CB227900)the National High Technology Joint Research Program of China(No.2012BAB13B00)
文摘To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehole.Combining with the engineering geological conditions,we built a numeral model to study the influence rule of the aquifer hydraulic pressure and seepage location of feeding borehole on the amount of seepage with fnite element numerical method.The results show that the nonlinear relationship is presented among the amount of seepage,the seepage location and aquifer hydraulic pressure.The higher the aquifer hydraulic pressure is,the closer the distance between seepage location and aquifer is,and the faster the harmful levels of aquifer will grow.In practice,we calculated the allowable seepage of feeding borehole by the optimum moisture content and natural moisture content of backflling materials,and then determined the protection zone of feeding borehole,so the moisture content of backflling materials can be controlled within the scope of optimum moisture content.
文摘No or little information on the use fresh(wet)housefly maggots(Musca domestica)in African catfish(Clarias gariepinus)fry feeding.Therefore,this study was conducted to investigate the effect of feeding on fresh(wet)housefly maggots with or without artificial diet on water quality,growth performance,survival percentage and feed utilization of African catfish fry under laboratory conditions.Housefly maggots produced from a mixture of poultry droppings and foods wastes,it was used to replace artificial feed at 0,50 and 100% levels.Catfish were fed artificial diet alone(Feed 1),fresh(wet)housefly maggots alone(Feed 2),and 50% fresh housefly maggots with 50% artificial diet(Feed 3)were prepared and tested on triplicate groups of African catfish fry(initial weight of 0.25±0.02 g)for 60 days.Results showed that final weight(g/fish)was significantly(P≤0.05)higher in fish fed on feed 3(6.03±0.08),followed by fish fed feed 2(4.62±0.27),followed by fish fed feed 1(3.15±0.68).Specific growth rate(%/day)was also significantly higher in fish fed on feed 3(5.31±0.10),followed by fish fed feed 2(4.86±0.03),followed by fish fed feed 1(4.18±0.24).The same trend was observed with total weight gain,percentage weight gain,daily growth rate and relative growth rate.Feed intake and protein intake were significantly(P≤0.05)higher in fish fed on feed 3 and fish fed on feed 2,followed by fish fed feed 1.While,feed conversion ratio(FCR)and protein efficiency ratio were not significantly(P>0.05),but the improvement in FCR recorded in catfish fry fed feed 3 and feed 2 under the experimental conditions.Survival percentage was within the range 55-75%,with insignificant differences(P>0.05)among treatments.The water quality parameters such as temperature,pH,dissolved oxygen,total ammonia,nitrite and nitrate were not significantly(P>0.05)between the treatments and were tolerable for Catfish culture.Accordingly,use of the 50% fresh(wet)housefly maggots with 50% artificial diet in African catfish fry feeding had positive effect on growth performance and reduce of the feed cost.
文摘As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introduces a new design of for steam feeding the water pump of an air-cooled unit using the back-pressure steam turbine as the prime motor. Using variable condition analysis on a 600 MW direct air-cooled unit, and with consideration of the effect on the ambient conditions, the feasibility, economy, and adaptability of the design are verified.
文摘A thermoeconomic optimization analysis is presented yielding simple algebraic formulae for estimating the optimum number of feed water heater and optimal area distribution among the feed water heaters for thermal power plants. The P1-P2 method is used in the present study, together with the thermoeconomic analyses of feed water heaters.
文摘Seasonal and sexual variations as well as the effect of dry feed supplement on total drinking water intake and its utilization were observed in mithun （Bosfrontalis） - a semi-wild animal found in North Eastern Hill Region （NEHR） of India. In a completely randomized design, twelve adult mithuns （B. frontalis） as per their sex and body weight were assigned in two different rearing systems （free grazing and free grazing with dry concentrate feed supplementation）, and ten growing male mithuns as per their body weight assigned in two different levels of dry concentrate feed supplementation （1.o kg and 2.0 kg dry concentrate feeds on green forage based diet） and in two different seasons （summer and winter）. It was observed that the environmental temperature had a significant effect on drinking water intake by mithuns. Drinking water consumption （per unit of body weight） was significantly （P 〈 0.05） higher in summer than in winter. Supplementation of concentrate feed on free grazing animals resulted in increase in water consumption. Total water consumption （drinking as well as performed water） was found to be 15.18 litres per 100 kg body weight by growing mithun. Feed dry matter and digestible nutrient intakes by growing mithun were observed to be increased with the increase of supplementation of dry concentrate feed. Roughage to concentrate ratio did not affect the nutrient digestibility. Mithun calves drank an average of 4.30 litres water for each kg of dry matter intake. Metabolic water was significantly （P〈0.01） increased with the increase of supplementation of concentrate feed whereas water turn over, which depends upon the body weight of the animals, did not differ significantly on offering of lower or higher level of dry feed. Faecal water loss of growing mithun was decreased with the increase in intake of concentrate feed and was estimated to be 33 - 46 % of total water intake. Excretion of water through faeces of mithun was about 3.8 % of body weight. It could, therefore, be inferred that water intake by mithun varied with seasons, rearing systems and dry feed consumption. As far as the water nutrition is concerned, it is needed to give an attention while feeding mithun in summer with dry feed supplementation under semi-intensive system of rearing.
文摘Feeding rhythm of common carp was investigated from 4℃ to 34℃. The results indicated that there was a diel feeding rhythm for both adult （630-850 g） and youth （61-91 g） at all tested temperatures. There were two main activity peaks at 8：00-11：00 a.m. and 19：00-23：00 p.m., during which feeding quantities were 10.68%-32.53% and 16.25%-33.41% of the daily intake, respectively. When water temperature dropped to below 10℃, the feeding peak concentrated at 8：00-11：00 a.m. and 19：00 p.m. to 4：00 a.m. At 6℃, though both adult and youth would still feed, the feeding quantities were only 0.01% and 0.35% of body mass. Daily feeding rate of adult and youth reached 1.21% and 2.63% at 14℃, respectively. Both adult and youth carps reached the maximum daily feeding rate at 28℃, being 2.84% and 12.06% of body mass, respectively. The daily feeding rate of adult and youth reduced suddenly after at 34℃, and the daily feeding rate was only 0.74% and 9.45% of body mass, respectively. There was significant difference in daily feeding rate at different water temperatures （P〈0.05）.
文摘In view of the fact that cages and bait are not allowed in large water surface aquiculture,1-2 kinds of new green feeds"plankton+microecologics"were developed to solve the problems of yield reduction,slow growth and difficulty in fishing of aquatic organisms caused by extensive mode.The new green feed is ecological,environmentally friendly and residue-free,which not only supplements nutrition but also meets the requirements of environmental protection.
文摘The study was conducted in Adami Tulu Jidokombolcha(ATJK),Bora,Dodola,Shala and Negele-Arsi districts with objective to assess main cattle feed resources,water sources and housing systems.A pre-tested,semi-structured questionnaire was used to conduct survey.About 240 respondents were identified using random sampling techniques.Collected data was analyzed by SPSS statistical software(Ver.24).Study result indicates that household in average had three hectares of land and allocated about two hectares of land for crop cultivation.Most respondents reported that cattle herding is not common during dry season while it is common during wet season.Survey result indicate that natural pasture,weed and maize tiller and stored crop residues are main feed resources in wet season while crop after math,crop residue and fodder trees are main resources during dry season.Brackish,local mineral and common salt are mineral sources for cattle in study areas.Lake,river and boreholes are important water sources in dry season where as ponds and rivers are main water sources during wet season for their cattle.The observed cattle watering frequency is mainly once a day.Housing system practiced in the study areas is mainly Kraal.The information generated from this study on land size per household,cattle herding system,feed resources,mineral sources,water sources,water utilization and housing type can be used as a baseline for any livestock development programs in those and similar areas.
文摘During the operation of the boiler in thermal power plant, the feed water pump, as the core part, plays an important role that cannot be ignored and is also an important basis for the orderly operation of the boiler. At present, the boilers of thermal power plants are constantly updated and upgraded to meet the actual operation requirements of thermal power plants, which also puts forward many new requirements for various functions of the boilers to a certain extent. The boiler feed water pump of thermal power plant plays an important role in the stability and safety of the boiler in operation. At present, in the boiler system of thermal power plants, regular maintenance is very important for the boiler feed pump. Only by strengthening the maintenance of the feed pump can the stable operation and reliability of the feed pump be ensured. Therefore, the paper will analyze the problem of boiler feedwater pump failure in thermal power plants and put forward effective maintenance countermeasures, in order to ensure the safe use of boilers in thermal power plants and strengthen the operation efficiency of boiler systems.
基金supported by the National Natural Science Foundation of China with Grant No.12202392the National Natural Science Foundation of China with Grant No.52476039the General Scientific Research Project of Zhejiang Education Department with Grant No.Y202457111.
文摘Seawater desalination is a key technological approach to address the global problem of water scarcity.Spacers in water treatment membrane modules play a critical role in the water treatment process.The use of a spacer improves fluid dynamics,enhances heat and mass transfer efficiency,and effectively mitigates concentration polarization,reduces fouling risks,and increases the long-term operational stability of the system as a whole.Although numerous novel spacer designs have been proposed in recent years,their large-scale commercialization still faces significant challenges.This review summarizes the critical strategies for improving hydraulic performance,mitigating scaling issues,and enhancing heat and mass transfer performance of spacers.It focuses on structural innovations that aim to optimize spacer performance and meet the diverse demands of various desalination methods.On the basis of a comprehensive analysis of spacer performance in typical application scenarios,it summarizes the limitations of current research,identifies future research directions,and highlights the potential of novel spacer designs to improve desalination efficiency.This review enhances understanding of the role of spacers in desalination systems and offers new research directions for future developments in seawater desalination technology.
