To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dime...To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.展开更多
The three-dimensional interactions of a perturbed premixed flame interface with a planar incident shock wave and its reflected shock waves are numerically simulated by solving the compressible,reactive Navier-Stokes e...The three-dimensional interactions of a perturbed premixed flame interface with a planar incident shock wave and its reflected shock waves are numerically simulated by solving the compressible,reactive Navier-Stokes equations with the high-resolution scheme and a single-step chemical reaction.The effects of the initial incident shock wave strength (Mach number) and the initial perturbation pattern of interface on the interactions are investigated.The distinct properties of perturbation growth on the flame interface during the interactions are presented.Our results show that perturbation growth is mainly attributed to the flame stretching and propagation.The flame stretching is associated with the larger-scale vortical flow due to RichtmyerMeshkov instability while the flame propagation is due to the chemical reaction.The mixing properties of unburned/burned gases on both sides of the flame are quantitatively analyzed by using integral and statistical diagnostics.The results show that the large-scale flow due to the vortical motion always plays a dominating role during the reactive interaction process;however,the effect of chemistry becomes more important at the later stage of the interactions,especially for higher Mach number cases.The scalar dissipation due to the molecular diffusion is always small in the present study and can be negligible.展开更多
In this paper,the momentum conservation equation in the longitudinal direction for simple railgun was deduced.Then,a three-dimensional model was established and the finite element method was utilized to simulate the p...In this paper,the momentum conservation equation in the longitudinal direction for simple railgun was deduced.Then,a three-dimensional model was established and the finite element method was utilized to simulate the problem.Based on the simulation,some results such as the surface force on the electromagnetic field,the electromagnetic force on the conductor in the longitudinal direction were obtained.Besides,the surface force density on different longitudinal section of railgun was analyzed and discussed in details.The results showed that the momentum of the railgun system was conserved when the surface force of the electromagnetic field was contained.Moreover,large amount of longitudinal force was transmitted to the breech by the electromagnetic field in the form of surface force.The exact position and distribution of recoil were related to the current input device.展开更多
Electrolyzed water(EW) can be produced by electrolysis of a dilute salt solution. Slightly acidic electrolyzed water(SAEW, p H 5.0–6.5) and neutral electrolyzed water(NEW, p H 6.5–8.5) are considered healthy and env...Electrolyzed water(EW) can be produced by electrolysis of a dilute salt solution. Slightly acidic electrolyzed water(SAEW, p H 5.0–6.5) and neutral electrolyzed water(NEW, p H 6.5–8.5) are considered healthy and environmentally friendly because no hazardous chemicals are added in its production, there is reduced corrosion of surfaces and it minimizes the potential for damage to animal and human health. Over the last decade, EW has become increasingly popular as an alternative disinfectant for decontamination in animal houses. However, there have been some issues related to EW that are not well known, including different mechanisms for generation of SAEW and NEW, and the antimicrobial mechanism of EW. This review covers the definitions of SAEW and NEW, different generation systems for SAEW and NEW, the antimicrobial mechanism of EW, and recent developments related to the application of SAEW and NEW in animal houses.展开更多
Major scientific studies have shown that global warming(i.e.increasing average temperature of the Earth)is now a reality.The aims of this paper are to broadly review the underlining causes of global warming,the genera...Major scientific studies have shown that global warming(i.e.increasing average temperature of the Earth)is now a reality.The aims of this paper are to broadly review the underlining causes of global warming,the general effects of global warming on social and environmental systems and the specific effects of resulting from global warming phenomena severe fluctuations in weather patterns,particularly heat waves on livestock health,welfare and productivity.Finally this article aims to summarise some common sense climate control methods and more importantly to highlight the required future research and development(R&D)work that is necessary to achieve a new level of building environment control capability,and thus ensure that the intensive livestock industries will be able to cope with the changed external climate.With the increasing temperatures on a global scale,the most direct effect of the high temperature on the animals is heat stress,which has been proven to have a variety of negative effects on animal health,welfare and productivity.Different potential measures could be taken in future to alleviate the increased heat stress.Some of these measures are mere adaptations or improvements of current engineering solutions.However,facing the complex challenges of global warming and particularly resulting from it the rapid increase of the number of consecutive days with significantly higher than average temperatures will probably require novel solutions,including new designs based on solid engineering judgment,development of new engineering standards and codes to guide designs,the exploration of new and superior building materials,the need for better energy management,and the development of substantially more“intelligent”control systems that will balance changing exterior disturbances,interior building loads and demands to the biological needs of the occupants of the structures.展开更多
Provision of nest boxes is necessary for laying hens,especially in non-cage systems.This study investigated the effects of nest width on nest utilization and mislaid eggs.Hy-Line Browns hens were transferred from conv...Provision of nest boxes is necessary for laying hens,especially in non-cage systems.This study investigated the effects of nest width on nest utilization and mislaid eggs.Hy-Line Browns hens were transferred from conventional cages to perchery pens at 12 weeks of age.Two experiments were conducted to mutually verify the hypothesis that narrowing group nests would improve nest utilization and reduce mislaid eggs.In experiment 1,group nests of 150 cm wide in two pens were partitioned at intervals of 50 cm and 37 cm,respectively.In experiment 2,partition panels were removed after acclimation.The number of mislaid eggs and nest eggs in each pre-set section were compared.Results indicated that narrowing group nests had positive effects on improving usage uniformity and efficiency of group nests.Nest eggs were more evenly distributed on the egg belt in both narrowed group nests,which was indicated by the significant decrease of variance among different sections(p<0.001).The proportion of mislaid eggs decreased by 3.5%in 37 cm treatment(p<0.05)and 4.7% in 50 cm treatment(p<0.001),respectively.As expected,reuse of the 150 cm group nests after removal of partition panels lowered the usage uniformity of group nests.A growth of three percentage points was found for the proportion of mislaid eggs after removing the partition panels in 50 cm treatment.The present results indicated that it is the width of the nest box that works for a better use of group nests.In conclusion,adding partition panels at intervals of 50 cm and 37 cm in group nests both are effective on nest usage and decreasing the occurrence of mislaid eggs.展开更多
Nutrients and water play an important role in microalgae cultivation.Using wastewater as a culture medium is a promising alternative to recycle nutrients and water,and for further developing microalgae-based products....Nutrients and water play an important role in microalgae cultivation.Using wastewater as a culture medium is a promising alternative to recycle nutrients and water,and for further developing microalgae-based products.In the present study,two species of microalgae,Chlorella sp.(high ammonia nitrogen tolerance)and Spirulinaplatensis (S.platensis,high growth rate),were cultured by using poultry wastewater through a two-stage cultivation system for algal biomass production.Ultrafiltration (UF)or centrifuge was used to harvest Chlorella-sp.from the first cultivation stage and to recycle culture medium for S.platensis growth in the second cultivation stage.Results showed the two-stage cultiyation system produced high microalgae biomass including 0.39g·L^-1 Chlorella sp.and 3.45g·L^-1 S.platensis in the first-stage and second-stage,respectively.In addition,the removal efficiencies of NH4+reached 19% and almost 100% in the first and the second stage,respectively. Total phosphorus (TP)removal reached 17% and 83%,and total organic carbon (TOC)removal reached 55% and 72% in the first and the second stage,respectively.UF and centrifuge can reeycle 96.8% and 100% water,respectively.This study provides a new method for the combined of pure microalgae cultivation and wastewater treatment with eulture medium recycling.展开更多
The degree-day method is widely used to determine energy consumption but cannot be directly applied to poultry buildings without improvements in its accuracy.This study was designed to optimize the degreeday calculati...The degree-day method is widely used to determine energy consumption but cannot be directly applied to poultry buildings without improvements in its accuracy.This study was designed to optimize the degreeday calculation and proposes a solar-air degree-day method,which can be used to calculate the cooling and heating degree-days and the annual cooling and heating loads under different climate conditions for poultry buildings.In this paper,the solar-air degree-day method was proposed,which considers the effects of solar radiation with different wall orientations and surface colors.Five Chinese cities,Harbin,Beijing,Chongqing,Kunming and Guangzhou,were selected to represent different climate zones to determine the solar-air degreedays.The heating and cooling energy requirements for different climates were compared by DeST(Designer’s Simulation Toolkit)simulation and the solar-air degreeday method.Approaches to decrease energy consumption were developed.The results showed that the maximum relative error was less than 10%,and the new method was not significantly different from the DeST simulation(P>0.05).The accuracy of calculating energy requirements was improved by the solar-air degree-day method in the different climate zones.Orientation and surface color effects on energy consumption need to be considered,and external walls of different orientations should have different surface colors.展开更多
Determining the optimum insulation thicknesses of external envelopes for livestock buildings are one of the most effective metrics to decrease energy requirements.This study was carried out to determine the optimum in...Determining the optimum insulation thicknesses of external envelopes for livestock buildings are one of the most effective metrics to decrease energy requirements.This study was carried out to determine the optimum insulation thicknesses for livestock buildings in different climate zones,to examine the effects of insulation thickness and material(foam glass,mineral wool,expanded polystyrene,foamed polyurethane,foamed polyvinyl chloride,and expanded polyethylene)on life cycle total cost,life cycle savings,and payback period.The finishing pig houses and laying hen buildings with sandwich wall structures(color steel laminboard)in five typical cities were studied using the degree-days method with economic models.Optimal insulation thicknesses ranged from 0.05 m to 0.25 m and 0.02 m to 0.24 m in finishing pig houses and poultry buildings,respectively;the life cycle total costs ranged from 16.49 to 37.98$/m2 and 13.37 to 36.84$/m2;the life cycle savings ranged from 29.13 to 220.60$/m2 and 0 to 202.13$/m2;and the payback period ranged from 1.11 to 5.81 years and 1.19 to 20.76 years,respectively.Foamed polyurethane provided the highest life cycle savings,while foam glass had the lowest.In this research,the insulation thicknesses for the sandwich structure livestock buildings external envelopes are optimized,and the energy saving can be obtained by using proper insulation thickness in different regions.Furthermore,it can increase the knowledge about energy consumption in the livestock buildings and the results can be also a useful tool for farmers.展开更多
Colony cages for natural mating have been applied on many layer breeder farms.However,feather pecking and cloacal cannibalism are considered as prominent problems for these systems.This study aimed to investigate the ...Colony cages for natural mating have been applied on many layer breeder farms.However,feather pecking and cloacal cannibalism are considered as prominent problems for these systems.This study aimed to investigate the effects on feather pecking and vent pecking behaviors by providing layer breeders with nest boxes(0.90 m L×0.40 m W×0.60 m H)in colony cages for natural mating(4.80 m L×1.20 m W×0.71 m H).Video recording and artificial observation were adopted.The results showed that the usage of nest boxes gradually increased from the beginning of nest boxes providing at the age of 37 weeks to the end of the experiment at the age of 55 weeks.The utilization rates of nest boxes were 36.75%,44.75%and 50.38%at the ages of 41 weeks,47 weeks and 53 weeks,respectively.The hens in the cages without nest boxes showed significantly more frequent gentle feather pecks(both given and received)than hens in the cages with nest boxes at the ages of 41 weeks,47 weeks and 53 weeks.A decreasing trend of gentle feather pecking frequency(both given and received)was found with the increasing age for both the two groups.No significant difference was found in the number of given or received severe feather pecks at the age of 41 weeks.The hens in the cages without nest boxes showed a significantly higher frequency of given and received severe feather pecks than hens in the cages with nest boxes at the ages of 47 weeks and 53 weeks(p<0.05).Both cannibalistic injury occurrence and mortality rate in the cages with nest boxes were significantly lower than those in the cages without nest boxes.In conclusion,providing nest boxes in colony cages for natural mating could decrease abnormal pecking behaviors and improve animal welfare conditions of layer breeders.展开更多
Pullets often raised in cage system from week 1 to week 13 in China,when transferred to aviary system after,there will be a problem with adapt.A large cage aviary unit(LCAU)system was developed,which allocated with fa...Pullets often raised in cage system from week 1 to week 13 in China,when transferred to aviary system after,there will be a problem with adapt.A large cage aviary unit(LCAU)system was developed,which allocated with facilities such as ramps to help cage reared hens to adapt to the multi-tier space.To investigate hens’adaptability to the new system,space use over time in the LCAU system during the first 10 days after hens transferred were recorded,instantaneous scan sampling and continuous focal sampling were used to assess the behavior difference of hens between the LCAU and conventional cage(CC)systems.On the first day of arrival,10.03% of hens reached the second tier(S2)and the third tier(S3)of the aviary.During the observation period,an average of 2.42% of hens climbed and stayed at the upper tiers every day.Space allowance on floor of the first tier(S1)increased from 444.62 cm^(2)/hen(91 d)to 586.32 cm^(2)/hen(100 d),which was more than 540 cm^(2)/hen in the CC system.Comfort behaviors in the LCAU system were significantly more than in the CC system(p<0.01)and hens performed more comfort behaviors with the increase of days after transferred.Hens ate and drank less in the LCAU system in the beginning,however,with the increasing use of upper space,hens ate and drank more and more in the LCAU system during the 10 days after transferred from CC system.Consequently,there were no difference of feed behavior between the CC and LCAU systems(p>0.05)on the last 5 days of the whole observing period.The results indicated that hens gradually learned to use the 3-dimensional space in the initial settling-in period and,gained a good welfare condition in LCAU system.Further studies are needed to investigate the three-dimensional preferences and behavior expression in difference period to bridge the gap in knowledge of space use capacity among adult laying hens.展开更多
As one of the main tumor-infiltrating immune cell types, tumor-associated macrophages (TAMs) determine the efficacy of immunotherapy. However, limited knowledge about their phenotypically and functionally heterogeneou...As one of the main tumor-infiltrating immune cell types, tumor-associated macrophages (TAMs) determine the efficacy of immunotherapy. However, limited knowledge about their phenotypically and functionally heterogeneous nature restricts their application in tumor immunotherapy. In this study, we identified a subpopulation of CD146+ TAMs that exerted antitumor activity in both human samples and animal models. CD146 expression in TAMs was negatively controlled by STAT3 signaling. Reducing this population of TAMs promoted tumor development by facilitating myeloid-derived suppressor cell recruitment via activation of JNK signaling. Interestingly, CD146 was involved in the NLRP3 inflammasome-mediated activation of macrophages in the tumor microenvironment, partially by inhibiting transmembrane protein 176B (TMEM176B), an immunoregulatory cation channel. Treatment with a TMEM176B inhibitor enhanced the antitumor activity of CD146+ TAMs. These data reveal a crucial antitumor role of CD146+ TAMs and highlight the promising immunotherapeutic approach of inhibiting CD146 and TMEM176B.展开更多
Poor early adaptation in aviaries has adverse effects on welfare and the later production.Effects of system modification by ramps and ladders on early adaptation of birds were investigated.A total of 240 pullets and 2...Poor early adaptation in aviaries has adverse effects on welfare and the later production.Effects of system modification by ramps and ladders on early adaptation of birds were investigated.A total of 240 pullets and 24 cockerels of Yukou Jing Pink II parent stock were allocated into six perchery compartments at the age of 83 days from conventional cages.Three compartments were modified with ramps of different angles,30°,40°and 30°&50°combination.The other compartments were fitted with 2 ladders,with 22 cm steps and 33 cm steps.Spatial distribution of birds and eggs,as well as the data of ramps and ladders utilization were used to assess birds’adaptation and the effectiveness of modification facilities.A higher proportion of hens got onto the tiered platforms in ramp group(p<0.001)and engaged in feeding(p=0.002).Inversely more than 85.0%of hens dwelled on the system floor in the ladder group for the whole observation period.The proportion of birds feeding increased over time(p<0.001),with the proportion of birds lying decreasing(p<0.001).A higher frequency of utilization of ramps was found compared with ladders(4.5-25.8 vs.2.8-14.7 times/40 birds per hour).For ramp use,79.3%of hens negotiated level change by using 30°ramp and behavioral process was also found related with the type of ramps.On the contrary,very few successful level changes were observed via ladders and 60%of ladder use was ended with birds backing to the system floor.Besides,a higher proportion of non-nest eggs was recorded in ladder group in the early laying period.These results indicated that modification of ramps is more applicable for improving birds’early adaptation and later production in perchery system of multi-tier,especially for pullets reared in conventional cages.展开更多
To study the influence of ripple cross angles on the resistance of wet curtains,wet curtains with different ripple cross angles(45°/45°,45°/15°)were tested on agricultural ventilation equipment per...To study the influence of ripple cross angles on the resistance of wet curtains,wet curtains with different ripple cross angles(45°/45°,45°/15°)were tested on agricultural ventilation equipment performance testing benches,and the static pressure drop under different wind speeds(1-3 m/s)was determined.Four turbulence models(κ-ε,RNGκ-ε,κ-ω,SSTκ-ω)were adopted for numerical simulations of the two types of wet curtain,and the simulations’results were compared with those of experiments.The average errors found are 41.1%,48.7%,27.1%,and 27.8%,respectively,and theκ-ωmodel is found to be the most suitable one for the calculation of wet curtain resistance among the four turbulence models.By using theκ-ωturbulence model,the static pressure drop performances of wet curtains with ripple cross angles 45°/35°and 45°/25°were calculated.Resistance increases with wind speed and ripple cross angles,and a large ripple cross angle has a higher resistance growth rate with increasing wind speed.展开更多
Algal blooms have become a worldwide environmental concern due to water eutrophication.Dianchi Lake in Yunnan Province,China is suffering from severe eutrophication and is listed in the Three Important Lakes Restorati...Algal blooms have become a worldwide environmental concern due to water eutrophication.Dianchi Lake in Yunnan Province,China is suffering from severe eutrophication and is listed in the Three Important Lakes Restoration Act of China.Hydrothermal liquefaction allows a promising and direct conversion of algal biomass into biocrude oil.In this study,algal samples were collected from Dianchi Lake after a separation procedure including dissolved air flotation with polyaluminum chloride and centrifugation during four months,April,June,August and October.The algal biochemical components varied over the period;lipids from 0.7%to 2.1%ash-free dry weight(afdw),protein from 20.9%to 33.4%afdw and ash from 36.6%to 45.2%dry weight.The algae in June had the highest lipid and protein concentrations,leading to a maximum biocrude oil yield of 24.3%afdw.Biodiversity analysis using pyrosequencing revealed different distributions of microbial communities,specifically Microcystis in April(89.0%),June(63.7%)and August(84.0%),and Synechococcus in April(2.2%),June(12.0%)and August(1.0%).This study demonstrated remarkable temporal changes in the biochemical composition and biodiversity of algae harvested from Dianchi Lake and changes in biocrude oil production potential.展开更多
文摘To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.
基金The work was supported by the National Natural Science Foundation of China(11372140).
文摘The three-dimensional interactions of a perturbed premixed flame interface with a planar incident shock wave and its reflected shock waves are numerically simulated by solving the compressible,reactive Navier-Stokes equations with the high-resolution scheme and a single-step chemical reaction.The effects of the initial incident shock wave strength (Mach number) and the initial perturbation pattern of interface on the interactions are investigated.The distinct properties of perturbation growth on the flame interface during the interactions are presented.Our results show that perturbation growth is mainly attributed to the flame stretching and propagation.The flame stretching is associated with the larger-scale vortical flow due to RichtmyerMeshkov instability while the flame propagation is due to the chemical reaction.The mixing properties of unburned/burned gases on both sides of the flame are quantitatively analyzed by using integral and statistical diagnostics.The results show that the large-scale flow due to the vortical motion always plays a dominating role during the reactive interaction process;however,the effect of chemistry becomes more important at the later stage of the interactions,especially for higher Mach number cases.The scalar dissipation due to the molecular diffusion is always small in the present study and can be negligible.
基金We thank Dr Bin Zhang （University of Michigan, USA） for providing the MCFD2 antibodies. This work was supported in part by the Life Science Special Fund of the Chinese Academy of Sciences for Human Genome Research （KJ95T-06 and KSCX1-Y02 to BML, NHJ and MLJ）, the National Natural Science Foundation of China （30225023 and 30430240 to BML and 90208011, 30300174, 30470856, 30421005 and 30623003 to NHJ）, the National Key Basic Research and Development Program of China （2006CB500807 to BML and 2002CB713802, 2005CB522704 and 2006CB943902 to NHJ）, the National High-Tech Research and Development Program of China （2006AA02ZI99 to BML and 2006AA02Z186 to NHJ）, the Shanghai Key Project of Basic Science Research （04DZ14005 to BML and 04DZ14005, 04DZ05608, 06DJI4001 and 06DZ22032 to NHJ）, the Council of the Shanghai Municipal for Science and Technology （05814578 to NHJ）, and the US National Institutes of Health （DA013471 and DA020555 to LY）.
文摘In this paper,the momentum conservation equation in the longitudinal direction for simple railgun was deduced.Then,a three-dimensional model was established and the finite element method was utilized to simulate the problem.Based on the simulation,some results such as the surface force on the electromagnetic field,the electromagnetic force on the conductor in the longitudinal direction were obtained.Besides,the surface force density on different longitudinal section of railgun was analyzed and discussed in details.The results showed that the momentum of the railgun system was conserved when the surface force of the electromagnetic field was contained.Moreover,large amount of longitudinal force was transmitted to the breech by the electromagnetic field in the form of surface force.The exact position and distribution of recoil were related to the current input device.
基金funded by the National Natural Science Foundation of China (30871957)Beijing Natural Science Foundation, China (6154029)China Agricultural Research System (CARS–41)
文摘Electrolyzed water(EW) can be produced by electrolysis of a dilute salt solution. Slightly acidic electrolyzed water(SAEW, p H 5.0–6.5) and neutral electrolyzed water(NEW, p H 6.5–8.5) are considered healthy and environmentally friendly because no hazardous chemicals are added in its production, there is reduced corrosion of surfaces and it minimizes the potential for damage to animal and human health. Over the last decade, EW has become increasingly popular as an alternative disinfectant for decontamination in animal houses. However, there have been some issues related to EW that are not well known, including different mechanisms for generation of SAEW and NEW, and the antimicrobial mechanism of EW. This review covers the definitions of SAEW and NEW, different generation systems for SAEW and NEW, the antimicrobial mechanism of EW, and recent developments related to the application of SAEW and NEW in animal houses.
文摘Major scientific studies have shown that global warming(i.e.increasing average temperature of the Earth)is now a reality.The aims of this paper are to broadly review the underlining causes of global warming,the general effects of global warming on social and environmental systems and the specific effects of resulting from global warming phenomena severe fluctuations in weather patterns,particularly heat waves on livestock health,welfare and productivity.Finally this article aims to summarise some common sense climate control methods and more importantly to highlight the required future research and development(R&D)work that is necessary to achieve a new level of building environment control capability,and thus ensure that the intensive livestock industries will be able to cope with the changed external climate.With the increasing temperatures on a global scale,the most direct effect of the high temperature on the animals is heat stress,which has been proven to have a variety of negative effects on animal health,welfare and productivity.Different potential measures could be taken in future to alleviate the increased heat stress.Some of these measures are mere adaptations or improvements of current engineering solutions.However,facing the complex challenges of global warming and particularly resulting from it the rapid increase of the number of consecutive days with significantly higher than average temperatures will probably require novel solutions,including new designs based on solid engineering judgment,development of new engineering standards and codes to guide designs,the exploration of new and superior building materials,the need for better energy management,and the development of substantially more“intelligent”control systems that will balance changing exterior disturbances,interior building loads and demands to the biological needs of the occupants of the structures.
基金This study was financially supported by the Developing Key Equipment for Digital Management and Monitoring Environment in Animal Production Modern Agricultural Industry Technology System(2013AA10230602)the Special Fund for Cultivation and Evolution of Beijing Innovative Base(Z171100002217018).
文摘Provision of nest boxes is necessary for laying hens,especially in non-cage systems.This study investigated the effects of nest width on nest utilization and mislaid eggs.Hy-Line Browns hens were transferred from conventional cages to perchery pens at 12 weeks of age.Two experiments were conducted to mutually verify the hypothesis that narrowing group nests would improve nest utilization and reduce mislaid eggs.In experiment 1,group nests of 150 cm wide in two pens were partitioned at intervals of 50 cm and 37 cm,respectively.In experiment 2,partition panels were removed after acclimation.The number of mislaid eggs and nest eggs in each pre-set section were compared.Results indicated that narrowing group nests had positive effects on improving usage uniformity and efficiency of group nests.Nest eggs were more evenly distributed on the egg belt in both narrowed group nests,which was indicated by the significant decrease of variance among different sections(p<0.001).The proportion of mislaid eggs decreased by 3.5%in 37 cm treatment(p<0.05)and 4.7% in 50 cm treatment(p<0.001),respectively.As expected,reuse of the 150 cm group nests after removal of partition panels lowered the usage uniformity of group nests.A growth of three percentage points was found for the proportion of mislaid eggs after removing the partition panels in 50 cm treatment.The present results indicated that it is the width of the nest box that works for a better use of group nests.In conclusion,adding partition panels at intervals of 50 cm and 37 cm in group nests both are effective on nest usage and decreasing the occurrence of mislaid eggs.
基金the Program of Outstanding Talents and Innovative Research Teams in Agriculture (2011-049) China Agricultural Research System (CARS-40)and National Natural Science Foundation of China (51576206).
文摘Nutrients and water play an important role in microalgae cultivation.Using wastewater as a culture medium is a promising alternative to recycle nutrients and water,and for further developing microalgae-based products.In the present study,two species of microalgae,Chlorella sp.(high ammonia nitrogen tolerance)and Spirulinaplatensis (S.platensis,high growth rate),were cultured by using poultry wastewater through a two-stage cultivation system for algal biomass production.Ultrafiltration (UF)or centrifuge was used to harvest Chlorella-sp.from the first cultivation stage and to recycle culture medium for S.platensis growth in the second cultivation stage.Results showed the two-stage cultiyation system produced high microalgae biomass including 0.39g·L^-1 Chlorella sp.and 3.45g·L^-1 S.platensis in the first-stage and second-stage,respectively.In addition,the removal efficiencies of NH4+reached 19% and almost 100% in the first and the second stage,respectively. Total phosphorus (TP)removal reached 17% and 83%,and total organic carbon (TOC)removal reached 55% and 72% in the first and the second stage,respectively.UF and centrifuge can reeycle 96.8% and 100% water,respectively.This study provides a new method for the combined of pure microalgae cultivation and wastewater treatment with eulture medium recycling.
基金This work was funded by the National Key R&D Program of China(2018YFD0500700)the China Agricultural Research System(CARS-40).
文摘The degree-day method is widely used to determine energy consumption but cannot be directly applied to poultry buildings without improvements in its accuracy.This study was designed to optimize the degreeday calculation and proposes a solar-air degree-day method,which can be used to calculate the cooling and heating degree-days and the annual cooling and heating loads under different climate conditions for poultry buildings.In this paper,the solar-air degree-day method was proposed,which considers the effects of solar radiation with different wall orientations and surface colors.Five Chinese cities,Harbin,Beijing,Chongqing,Kunming and Guangzhou,were selected to represent different climate zones to determine the solar-air degreedays.The heating and cooling energy requirements for different climates were compared by DeST(Designer’s Simulation Toolkit)simulation and the solar-air degreeday method.Approaches to decrease energy consumption were developed.The results showed that the maximum relative error was less than 10%,and the new method was not significantly different from the DeST simulation(P>0.05).The accuracy of calculating energy requirements was improved by the solar-air degree-day method in the different climate zones.Orientation and surface color effects on energy consumption need to be considered,and external walls of different orientations should have different surface colors.
基金This work was supported by National Key R&D Program of China(2018YFD0500700)and the China Agricultural Research System(CARS-40).
文摘Determining the optimum insulation thicknesses of external envelopes for livestock buildings are one of the most effective metrics to decrease energy requirements.This study was carried out to determine the optimum insulation thicknesses for livestock buildings in different climate zones,to examine the effects of insulation thickness and material(foam glass,mineral wool,expanded polystyrene,foamed polyurethane,foamed polyvinyl chloride,and expanded polyethylene)on life cycle total cost,life cycle savings,and payback period.The finishing pig houses and laying hen buildings with sandwich wall structures(color steel laminboard)in five typical cities were studied using the degree-days method with economic models.Optimal insulation thicknesses ranged from 0.05 m to 0.25 m and 0.02 m to 0.24 m in finishing pig houses and poultry buildings,respectively;the life cycle total costs ranged from 16.49 to 37.98$/m2 and 13.37 to 36.84$/m2;the life cycle savings ranged from 29.13 to 220.60$/m2 and 0 to 202.13$/m2;and the payback period ranged from 1.11 to 5.81 years and 1.19 to 20.76 years,respectively.Foamed polyurethane provided the highest life cycle savings,while foam glass had the lowest.In this research,the insulation thicknesses for the sandwich structure livestock buildings external envelopes are optimized,and the energy saving can be obtained by using proper insulation thickness in different regions.Furthermore,it can increase the knowledge about energy consumption in the livestock buildings and the results can be also a useful tool for farmers.
基金This research was funded by China Agricultural Research System(CARS-40)Beijing Science&Technology Committee Special Project(Z171100002217018).
文摘Colony cages for natural mating have been applied on many layer breeder farms.However,feather pecking and cloacal cannibalism are considered as prominent problems for these systems.This study aimed to investigate the effects on feather pecking and vent pecking behaviors by providing layer breeders with nest boxes(0.90 m L×0.40 m W×0.60 m H)in colony cages for natural mating(4.80 m L×1.20 m W×0.71 m H).Video recording and artificial observation were adopted.The results showed that the usage of nest boxes gradually increased from the beginning of nest boxes providing at the age of 37 weeks to the end of the experiment at the age of 55 weeks.The utilization rates of nest boxes were 36.75%,44.75%and 50.38%at the ages of 41 weeks,47 weeks and 53 weeks,respectively.The hens in the cages without nest boxes showed significantly more frequent gentle feather pecks(both given and received)than hens in the cages with nest boxes at the ages of 41 weeks,47 weeks and 53 weeks.A decreasing trend of gentle feather pecking frequency(both given and received)was found with the increasing age for both the two groups.No significant difference was found in the number of given or received severe feather pecks at the age of 41 weeks.The hens in the cages without nest boxes showed a significantly higher frequency of given and received severe feather pecks than hens in the cages with nest boxes at the ages of 47 weeks and 53 weeks(p<0.05).Both cannibalistic injury occurrence and mortality rate in the cages with nest boxes were significantly lower than those in the cages without nest boxes.In conclusion,providing nest boxes in colony cages for natural mating could decrease abnormal pecking behaviors and improve animal welfare conditions of layer breeders.
基金The authors wish to acknowledge the financial support of the Beijing Science&Technology Commiittee Special Project(Z171100002217018)China Agricultural Research System(CARS-40)Natural Science Foundation of China(31601981).
文摘Pullets often raised in cage system from week 1 to week 13 in China,when transferred to aviary system after,there will be a problem with adapt.A large cage aviary unit(LCAU)system was developed,which allocated with facilities such as ramps to help cage reared hens to adapt to the multi-tier space.To investigate hens’adaptability to the new system,space use over time in the LCAU system during the first 10 days after hens transferred were recorded,instantaneous scan sampling and continuous focal sampling were used to assess the behavior difference of hens between the LCAU and conventional cage(CC)systems.On the first day of arrival,10.03% of hens reached the second tier(S2)and the third tier(S3)of the aviary.During the observation period,an average of 2.42% of hens climbed and stayed at the upper tiers every day.Space allowance on floor of the first tier(S1)increased from 444.62 cm^(2)/hen(91 d)to 586.32 cm^(2)/hen(100 d),which was more than 540 cm^(2)/hen in the CC system.Comfort behaviors in the LCAU system were significantly more than in the CC system(p<0.01)and hens performed more comfort behaviors with the increase of days after transferred.Hens ate and drank less in the LCAU system in the beginning,however,with the increasing use of upper space,hens ate and drank more and more in the LCAU system during the 10 days after transferred from CC system.Consequently,there were no difference of feed behavior between the CC and LCAU systems(p>0.05)on the last 5 days of the whole observing period.The results indicated that hens gradually learned to use the 3-dimensional space in the initial settling-in period and,gained a good welfare condition in LCAU system.Further studies are needed to investigate the three-dimensional preferences and behavior expression in difference period to bridge the gap in knowledge of space use capacity among adult laying hens.
基金supported in part by grants from the Beijing Natural Science Foundation of China(Grant No.7192123,7222117)the National Natural Science Foundation of China(Grant No.31770793,82000812)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2018122).
文摘As one of the main tumor-infiltrating immune cell types, tumor-associated macrophages (TAMs) determine the efficacy of immunotherapy. However, limited knowledge about their phenotypically and functionally heterogeneous nature restricts their application in tumor immunotherapy. In this study, we identified a subpopulation of CD146+ TAMs that exerted antitumor activity in both human samples and animal models. CD146 expression in TAMs was negatively controlled by STAT3 signaling. Reducing this population of TAMs promoted tumor development by facilitating myeloid-derived suppressor cell recruitment via activation of JNK signaling. Interestingly, CD146 was involved in the NLRP3 inflammasome-mediated activation of macrophages in the tumor microenvironment, partially by inhibiting transmembrane protein 176B (TMEM176B), an immunoregulatory cation channel. Treatment with a TMEM176B inhibitor enhanced the antitumor activity of CD146+ TAMs. These data reveal a crucial antitumor role of CD146+ TAMs and highlight the promising immunotherapeutic approach of inhibiting CD146 and TMEM176B.
基金This study was funded by China Agricultural Research System-National Technology System for Layer Industry(CARS-40-19K)National Natural Science Foundation of China(31601981).
文摘Poor early adaptation in aviaries has adverse effects on welfare and the later production.Effects of system modification by ramps and ladders on early adaptation of birds were investigated.A total of 240 pullets and 24 cockerels of Yukou Jing Pink II parent stock were allocated into six perchery compartments at the age of 83 days from conventional cages.Three compartments were modified with ramps of different angles,30°,40°and 30°&50°combination.The other compartments were fitted with 2 ladders,with 22 cm steps and 33 cm steps.Spatial distribution of birds and eggs,as well as the data of ramps and ladders utilization were used to assess birds’adaptation and the effectiveness of modification facilities.A higher proportion of hens got onto the tiered platforms in ramp group(p<0.001)and engaged in feeding(p=0.002).Inversely more than 85.0%of hens dwelled on the system floor in the ladder group for the whole observation period.The proportion of birds feeding increased over time(p<0.001),with the proportion of birds lying decreasing(p<0.001).A higher frequency of utilization of ramps was found compared with ladders(4.5-25.8 vs.2.8-14.7 times/40 birds per hour).For ramp use,79.3%of hens negotiated level change by using 30°ramp and behavioral process was also found related with the type of ramps.On the contrary,very few successful level changes were observed via ladders and 60%of ladder use was ended with birds backing to the system floor.Besides,a higher proportion of non-nest eggs was recorded in ladder group in the early laying period.These results indicated that modification of ramps is more applicable for improving birds’early adaptation and later production in perchery system of multi-tier,especially for pullets reared in conventional cages.
基金This study was funded by the China Agricultural Research System(CARS-36)the National key research and development plan special project(2018YFF0213604)the National Natural Science Foundation of China(31402115)。
文摘To study the influence of ripple cross angles on the resistance of wet curtains,wet curtains with different ripple cross angles(45°/45°,45°/15°)were tested on agricultural ventilation equipment performance testing benches,and the static pressure drop under different wind speeds(1-3 m/s)was determined.Four turbulence models(κ-ε,RNGκ-ε,κ-ω,SSTκ-ω)were adopted for numerical simulations of the two types of wet curtain,and the simulations’results were compared with those of experiments.The average errors found are 41.1%,48.7%,27.1%,and 27.8%,respectively,and theκ-ωmodel is found to be the most suitable one for the calculation of wet curtain resistance among the four turbulence models.By using theκ-ωturbulence model,the static pressure drop performances of wet curtains with ripple cross angles 45°/35°and 45°/25°were calculated.Resistance increases with wind speed and ripple cross angles,and a large ripple cross angle has a higher resistance growth rate with increasing wind speed.
基金the Chinese Universities Scientific Fund(2015SYL004).
文摘Algal blooms have become a worldwide environmental concern due to water eutrophication.Dianchi Lake in Yunnan Province,China is suffering from severe eutrophication and is listed in the Three Important Lakes Restoration Act of China.Hydrothermal liquefaction allows a promising and direct conversion of algal biomass into biocrude oil.In this study,algal samples were collected from Dianchi Lake after a separation procedure including dissolved air flotation with polyaluminum chloride and centrifugation during four months,April,June,August and October.The algal biochemical components varied over the period;lipids from 0.7%to 2.1%ash-free dry weight(afdw),protein from 20.9%to 33.4%afdw and ash from 36.6%to 45.2%dry weight.The algae in June had the highest lipid and protein concentrations,leading to a maximum biocrude oil yield of 24.3%afdw.Biodiversity analysis using pyrosequencing revealed different distributions of microbial communities,specifically Microcystis in April(89.0%),June(63.7%)and August(84.0%),and Synechococcus in April(2.2%),June(12.0%)and August(1.0%).This study demonstrated remarkable temporal changes in the biochemical composition and biodiversity of algae harvested from Dianchi Lake and changes in biocrude oil production potential.
