The present study was conducted to evaluate the effects of carrot leaf powder in the diet on reproductive and growth characteristics in rabbits. Thirty sexually matured rabbits does of 8 months old, 3.00 to 3.20 kg, w...The present study was conducted to evaluate the effects of carrot leaf powder in the diet on reproductive and growth characteristics in rabbits. Thirty sexually matured rabbits does of 8 months old, 3.00 to 3.20 kg, were divided into three groups of 10 rabbits each, which were comparable in terms of body weight. Throughout the experiment, the rabbits of group 1 (control group) were fed ad libitum with a feed not containing carrot leaf powder (control ration), while those of groups 2 and 3 received the control ration supplemented with carrot leaf powder in concentrations of 0.5% and 1% respectively. Data was collected on feed intake, weight gain, receptivity, fertility, gestation length of does, litter size, weight, viability and sex ratio of the young rabbits till 5 weeks post-partum. There was no significant (P > 0.05) difference in the fertility rate, gestation duration and sex ratio of the kits with reference to the control. Litter size at birth was not significantly (P > 0.05) influenced in does fed diets containing carrot leaf powder compared to the control. However, the reversed effects were observed at five weeks post-partum. The live weight of weaned kits and weight gain of rabbit does at birth were significantly (P < 0.05) increased in treated rabbits compared to the control. The supplementation of carrot leaf powder in feed can improve production performance in female rabbits, through their antioxidant activities thanks to their various components, thus fighting against oxidative stress effects to which animals are exposed both from endogenous and environmental sources.展开更多
Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase variations.The present study investigated...Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase variations.The present study investigated the impact of parameters in slurry preparation and heat treatment on the yield strength and ductility of T6 heat-treated A356 Al-Si alloy using rapid slurry forming(RSF)semi-solid casting.The focus was primarily on the robustness of mechanical properties based on Taguchi design method.By analyzing signal-to-noise ratio and minimum value calculated from-3S,the optimum slurry preparation parameters and heat treatment parameters were determined to be no quench,enthalpy exchange material(EEM)temperature of 140℃,EEM-to-melt ratio of 6mass%,stirring time of 18 s,solution heat treated at 520℃ for 2 h,and ageing heat treated at 190℃ for 6 h.In a small batch validation,the-3S yield strength and-3S elongation reach 256.1 MPa and 5.03% respectively,showing a satisfactory robustness.The hardness and microstructure of heat-treated samples with the best and worst properties were characterized to gain insight into the underlying mechanisms affecting the mean value and variations of mechanical properties.展开更多
With the continuous improvement of permanent magnet(PM)wind generators'capacity and power density,the design of reasonable and efficient cooling structures has become a focus.This paper proposes a fully enclosed s...With the continuous improvement of permanent magnet(PM)wind generators'capacity and power density,the design of reasonable and efficient cooling structures has become a focus.This paper proposes a fully enclosed self-circulating hydrogen cooling structure for a originally forced-air-cooled direct-drive PM wind generator.The proposed hydrogen cooling system uses the rotor panel supports that hold the rotor core as the radial blades,and the hydrogen flow is driven by the rotating plates to flow through the axial and radial vents to realize the efficient cooling of the generator.According to the structural parameters of the cooling system,the Taguchi method is used to decouple the structural variables.The influence of the size of each cooling structure on the heat dissipation characteristic is analyzed,and the appropriate cooling structure scheme is determined.展开更多
In recent times, lithium-ion batteries have been widely used owing to their high energy density, extended cycle lifespan, and minimal self-discharge rate. The design of high-speed rechargeable lithium-ion batteries fa...In recent times, lithium-ion batteries have been widely used owing to their high energy density, extended cycle lifespan, and minimal self-discharge rate. The design of high-speed rechargeable lithium-ion batteries faces a significant challenge owing to the need to increase average electric power during charging. This challenge results from the direct influence of the power level on the rate of chemical reactions occurring in the battery electrodes. In this study, the Taguchi optimization method was used to enhance the average electric power during the charging process of lithium-ion batteries. The Taguchi technique is a statistical strategy that facilitates the systematic and efficient evaluation of numerous experimental variables. The proposed method involved varying seven input factors, including positive electrode thickness, positive electrode material, positive electrode active material volume fraction, negative electrode active material volume fraction, separator thickness, positive current collector thickness, and negative current collector thickness. Three levels were assigned to each control factor to identify the optimal conditions and maximize the average electric power during charging. Moreover, a variance assessment analysis was conducted to validate the results obtained from the Taguchi analysis. The results revealed that the Taguchi method was an eff ective approach for optimizing the average electric power during the charging of lithium-ion batteries. This indicates that the positive electrode material, followed by the separator thickness and the negative electrode active material volume fraction, was key factors significantly infl uencing the average electric power during the charging of lithium-ion batteries response. The identification of optimal conditions resulted in the improved performance of lithium-ion batteries, extending their potential in various applications. Particularly, lithium-ion batteries with average electric power of 16 W and 17 W during charging were designed and simulated in the range of 0-12000 s using COMSOL Multiphysics software. This study efficiently employs the Taguchi optimization technique to develop lithium-ion batteries capable of storing a predetermined average electric power during the charging phase. Therefore, this method enables the battery to achieve complete charging within a specific timeframe tailored to a specificapplication. The implementation of this method can save costs, time, and materials compared with other alternative methods, such as the trial-and-error approach.展开更多
航空发动机的性能受可调几何变量控制规律的影响十分明显,在工程试验中,通常采用不同的几何调整措施实现发动机性能优化。但随着可调几何变量数量的增加,性能寻优工作越来越难。为明确不同几何调整措施对发动机性能的影响,获取使发动机...航空发动机的性能受可调几何变量控制规律的影响十分明显,在工程试验中,通常采用不同的几何调整措施实现发动机性能优化。但随着可调几何变量数量的增加,性能寻优工作越来越难。为明确不同几何调整措施对发动机性能的影响,获取使发动机性能较优的可调几何变量控制规律组合调整方法,在尽可能少的试验次数下实现发动机性能优化,引入了一种高效、简便的试验设计DOE(Design of Experiment)法。采用DOE技术,以降低发动机排气温度为最终优化目标制定了试验计划,确定将风扇进口导向叶片角度(α_(1))、高压压气机可调静子叶片角度(α_(2))、喷管喉道面积(A_(8))作为可调几何变量,并在给定的调节范围内开展了试验,录取了不同几何调整措施对应的发动机性能参数。根据性能录取结果拟合了性能优化模型,采用DOE自带的响应优化器功能确定了3个可调几何变量组合调整方法,并对更低的排气温度进行了预测计算,得到了满意的可调几何变量控制规律组合调整策略,最终完成了试验的优化设计。分析结果表明,降低发动机排气温度,可采取增加A_(8)或者减小α_(2)的措施,但α_(1)和A_(8)之间存在明显的交互效应,台架上需参考A_(8)的大小确定α_(1)的调试方法;DOE预测功能通过对可调因子水平进行扩展,可以实现性能寻优;DOE能够高效地实现多可调变量下的试验优化设计,具有较好的使用前景。展开更多
焊接工艺参数直接影响着焊缝成形及接头性能的好坏。由于焊接过程涉及的参数较多,采用传统实验方法研究往往不够现实。将实验设计DOE(Design of Experiment)等优化设计方法应用于焊接工艺研究,通过科学严谨的实验设计,建立相关数学模型...焊接工艺参数直接影响着焊缝成形及接头性能的好坏。由于焊接过程涉及的参数较多,采用传统实验方法研究往往不够现实。将实验设计DOE(Design of Experiment)等优化设计方法应用于焊接工艺研究,通过科学严谨的实验设计,建立相关数学模型,找出焊接工艺参数与焊缝质量参数间的影响关系,实现焊接过程优化设计和焊接主要工艺参数组合预测,从而获得良好的焊缝成形和接头性能,对于焊接试验研究和焊接实际生产过程优化都具有重要意义。着重介绍了国内外DOE方法在焊接过程实验设计和焊缝质量最优化等方面的研究应用和进展。展开更多
文摘The present study was conducted to evaluate the effects of carrot leaf powder in the diet on reproductive and growth characteristics in rabbits. Thirty sexually matured rabbits does of 8 months old, 3.00 to 3.20 kg, were divided into three groups of 10 rabbits each, which were comparable in terms of body weight. Throughout the experiment, the rabbits of group 1 (control group) were fed ad libitum with a feed not containing carrot leaf powder (control ration), while those of groups 2 and 3 received the control ration supplemented with carrot leaf powder in concentrations of 0.5% and 1% respectively. Data was collected on feed intake, weight gain, receptivity, fertility, gestation length of does, litter size, weight, viability and sex ratio of the young rabbits till 5 weeks post-partum. There was no significant (P > 0.05) difference in the fertility rate, gestation duration and sex ratio of the kits with reference to the control. Litter size at birth was not significantly (P > 0.05) influenced in does fed diets containing carrot leaf powder compared to the control. However, the reversed effects were observed at five weeks post-partum. The live weight of weaned kits and weight gain of rabbit does at birth were significantly (P < 0.05) increased in treated rabbits compared to the control. The supplementation of carrot leaf powder in feed can improve production performance in female rabbits, through their antioxidant activities thanks to their various components, thus fighting against oxidative stress effects to which animals are exposed both from endogenous and environmental sources.
文摘Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase variations.The present study investigated the impact of parameters in slurry preparation and heat treatment on the yield strength and ductility of T6 heat-treated A356 Al-Si alloy using rapid slurry forming(RSF)semi-solid casting.The focus was primarily on the robustness of mechanical properties based on Taguchi design method.By analyzing signal-to-noise ratio and minimum value calculated from-3S,the optimum slurry preparation parameters and heat treatment parameters were determined to be no quench,enthalpy exchange material(EEM)temperature of 140℃,EEM-to-melt ratio of 6mass%,stirring time of 18 s,solution heat treated at 520℃ for 2 h,and ageing heat treated at 190℃ for 6 h.In a small batch validation,the-3S yield strength and-3S elongation reach 256.1 MPa and 5.03% respectively,showing a satisfactory robustness.The hardness and microstructure of heat-treated samples with the best and worst properties were characterized to gain insight into the underlying mechanisms affecting the mean value and variations of mechanical properties.
基金supported in part by the“Chunhui Plan”Collaborative Research Project of Chinese Ministry of Education under Grant HZKY20220604by the National Natural Science Foundation of China under Grant 52107007。
文摘With the continuous improvement of permanent magnet(PM)wind generators'capacity and power density,the design of reasonable and efficient cooling structures has become a focus.This paper proposes a fully enclosed self-circulating hydrogen cooling structure for a originally forced-air-cooled direct-drive PM wind generator.The proposed hydrogen cooling system uses the rotor panel supports that hold the rotor core as the radial blades,and the hydrogen flow is driven by the rotating plates to flow through the axial and radial vents to realize the efficient cooling of the generator.According to the structural parameters of the cooling system,the Taguchi method is used to decouple the structural variables.The influence of the size of each cooling structure on the heat dissipation characteristic is analyzed,and the appropriate cooling structure scheme is determined.
文摘In recent times, lithium-ion batteries have been widely used owing to their high energy density, extended cycle lifespan, and minimal self-discharge rate. The design of high-speed rechargeable lithium-ion batteries faces a significant challenge owing to the need to increase average electric power during charging. This challenge results from the direct influence of the power level on the rate of chemical reactions occurring in the battery electrodes. In this study, the Taguchi optimization method was used to enhance the average electric power during the charging process of lithium-ion batteries. The Taguchi technique is a statistical strategy that facilitates the systematic and efficient evaluation of numerous experimental variables. The proposed method involved varying seven input factors, including positive electrode thickness, positive electrode material, positive electrode active material volume fraction, negative electrode active material volume fraction, separator thickness, positive current collector thickness, and negative current collector thickness. Three levels were assigned to each control factor to identify the optimal conditions and maximize the average electric power during charging. Moreover, a variance assessment analysis was conducted to validate the results obtained from the Taguchi analysis. The results revealed that the Taguchi method was an eff ective approach for optimizing the average electric power during the charging of lithium-ion batteries. This indicates that the positive electrode material, followed by the separator thickness and the negative electrode active material volume fraction, was key factors significantly infl uencing the average electric power during the charging of lithium-ion batteries response. The identification of optimal conditions resulted in the improved performance of lithium-ion batteries, extending their potential in various applications. Particularly, lithium-ion batteries with average electric power of 16 W and 17 W during charging were designed and simulated in the range of 0-12000 s using COMSOL Multiphysics software. This study efficiently employs the Taguchi optimization technique to develop lithium-ion batteries capable of storing a predetermined average electric power during the charging phase. Therefore, this method enables the battery to achieve complete charging within a specific timeframe tailored to a specificapplication. The implementation of this method can save costs, time, and materials compared with other alternative methods, such as the trial-and-error approach.
文摘航空发动机的性能受可调几何变量控制规律的影响十分明显,在工程试验中,通常采用不同的几何调整措施实现发动机性能优化。但随着可调几何变量数量的增加,性能寻优工作越来越难。为明确不同几何调整措施对发动机性能的影响,获取使发动机性能较优的可调几何变量控制规律组合调整方法,在尽可能少的试验次数下实现发动机性能优化,引入了一种高效、简便的试验设计DOE(Design of Experiment)法。采用DOE技术,以降低发动机排气温度为最终优化目标制定了试验计划,确定将风扇进口导向叶片角度(α_(1))、高压压气机可调静子叶片角度(α_(2))、喷管喉道面积(A_(8))作为可调几何变量,并在给定的调节范围内开展了试验,录取了不同几何调整措施对应的发动机性能参数。根据性能录取结果拟合了性能优化模型,采用DOE自带的响应优化器功能确定了3个可调几何变量组合调整方法,并对更低的排气温度进行了预测计算,得到了满意的可调几何变量控制规律组合调整策略,最终完成了试验的优化设计。分析结果表明,降低发动机排气温度,可采取增加A_(8)或者减小α_(2)的措施,但α_(1)和A_(8)之间存在明显的交互效应,台架上需参考A_(8)的大小确定α_(1)的调试方法;DOE预测功能通过对可调因子水平进行扩展,可以实现性能寻优;DOE能够高效地实现多可调变量下的试验优化设计,具有较好的使用前景。
文摘焊接工艺参数直接影响着焊缝成形及接头性能的好坏。由于焊接过程涉及的参数较多,采用传统实验方法研究往往不够现实。将实验设计DOE(Design of Experiment)等优化设计方法应用于焊接工艺研究,通过科学严谨的实验设计,建立相关数学模型,找出焊接工艺参数与焊缝质量参数间的影响关系,实现焊接过程优化设计和焊接主要工艺参数组合预测,从而获得良好的焊缝成形和接头性能,对于焊接试验研究和焊接实际生产过程优化都具有重要意义。着重介绍了国内外DOE方法在焊接过程实验设计和焊缝质量最优化等方面的研究应用和进展。
