This paper describes the design of a ventilation system to be paired with a carbon capture system. The ventilation system utilizes the geometry of the George C. Wallace tunnel, located in the City of Mobile, Alabama, ...This paper describes the design of a ventilation system to be paired with a carbon capture system. The ventilation system utilizes the geometry of the George C. Wallace tunnel, located in the City of Mobile, Alabama, USA to capture and redirect emissions to a direct air capture (DAC) device to sequester 25% of the total CO2 mass generated from inside the tunnel. The total CO2 mass rate for the westbound traffic between the week-day hours of 7 a.m. and 6 p.m. has been estimated between 2,300 to 3,000 lbs./hr. By sequestering these emissions, the overall surrounding air quality was shown to be improved to a level that mirrors that from the pre-US industrial era of 270 ppm.展开更多
The farming-pastoral ecotone in northern China is an extremely fr@e ecological zone where wind erosion of cropland and rangeland is easy to occur. In this study, using a portable wind tunnel as a wind simulator, we co...The farming-pastoral ecotone in northern China is an extremely fr@e ecological zone where wind erosion of cropland and rangeland is easy to occur. In this study, using a portable wind tunnel as a wind simulator, we conducted field simulated wind erosion experiments combined with laboratory analysis to investigate wind erosion of soils in trampled rangeland, non-tilled cropland and tilled cropland in Yanchi County, China. The results showed that compared with rangeland, the cropland had a higher soil water holding capacity and lower soil bulk density. The wind erosion rate of trampled rangeland was much higher than those of non-tilled cropland and tilled cropland. For cropland, the wind erosion rate of the soil after tilling was surprisingly less than that of the soil before tilling. With increasing of wind speed, the volume mean diameter of the eroded sediment collected by the trough in the wind tunnel generally increased while the clay and silt content decreased for all soils. The temporal variation in wind erosion of the trampled rangeland indicated that particle entrainment and dust emission decreased exponentially with erosion time through the successive wind erosion events due to the exhaustion of erodible particles.展开更多
针对岩爆样本数据噪声高、数量少从而导致岩爆等级预测准确率较低的问题,提出了基于非线性分数阶中值鉴别空间学习(nonlinear fractional-order median discriminative space learning,NFMDSL)的岩爆预测方法。该方法用类中值代替类均值...针对岩爆样本数据噪声高、数量少从而导致岩爆等级预测准确率较低的问题,提出了基于非线性分数阶中值鉴别空间学习(nonlinear fractional-order median discriminative space learning,NFMDSL)的岩爆预测方法。该方法用类中值代替类均值,构建了中值鉴别空间学习方法,更好地保留了样本的有效信息,降低了噪声对预测效果的影响。为了有效捕捉岩爆数据间的非线性鉴别结构,进一步借助核技术将样本数据投影到核空间中。此外,引入分数阶对散度矩阵的特征值和奇异值进行重新估计,可以从少量样本中提取出具有良好区分能力的岩爆特征。结果表明,NFMDSL方法在岩爆等级预测中的平均准确率达到了95.75%,相比其他方法具有更高的准确率和更强的鲁棒性。该方法能够有效应用于矿山和隧道工程领域的岩爆预测。展开更多
文摘This paper describes the design of a ventilation system to be paired with a carbon capture system. The ventilation system utilizes the geometry of the George C. Wallace tunnel, located in the City of Mobile, Alabama, USA to capture and redirect emissions to a direct air capture (DAC) device to sequester 25% of the total CO2 mass generated from inside the tunnel. The total CO2 mass rate for the westbound traffic between the week-day hours of 7 a.m. and 6 p.m. has been estimated between 2,300 to 3,000 lbs./hr. By sequestering these emissions, the overall surrounding air quality was shown to be improved to a level that mirrors that from the pre-US industrial era of 270 ppm.
基金supported by the National Natural Science Foundation of China (41401310, 41661003)the Science-Technology Research Project of Ningxia Environmental Protection Department
文摘The farming-pastoral ecotone in northern China is an extremely fr@e ecological zone where wind erosion of cropland and rangeland is easy to occur. In this study, using a portable wind tunnel as a wind simulator, we conducted field simulated wind erosion experiments combined with laboratory analysis to investigate wind erosion of soils in trampled rangeland, non-tilled cropland and tilled cropland in Yanchi County, China. The results showed that compared with rangeland, the cropland had a higher soil water holding capacity and lower soil bulk density. The wind erosion rate of trampled rangeland was much higher than those of non-tilled cropland and tilled cropland. For cropland, the wind erosion rate of the soil after tilling was surprisingly less than that of the soil before tilling. With increasing of wind speed, the volume mean diameter of the eroded sediment collected by the trough in the wind tunnel generally increased while the clay and silt content decreased for all soils. The temporal variation in wind erosion of the trampled rangeland indicated that particle entrainment and dust emission decreased exponentially with erosion time through the successive wind erosion events due to the exhaustion of erodible particles.
文摘针对岩爆样本数据噪声高、数量少从而导致岩爆等级预测准确率较低的问题,提出了基于非线性分数阶中值鉴别空间学习(nonlinear fractional-order median discriminative space learning,NFMDSL)的岩爆预测方法。该方法用类中值代替类均值,构建了中值鉴别空间学习方法,更好地保留了样本的有效信息,降低了噪声对预测效果的影响。为了有效捕捉岩爆数据间的非线性鉴别结构,进一步借助核技术将样本数据投影到核空间中。此外,引入分数阶对散度矩阵的特征值和奇异值进行重新估计,可以从少量样本中提取出具有良好区分能力的岩爆特征。结果表明,NFMDSL方法在岩爆等级预测中的平均准确率达到了95.75%,相比其他方法具有更高的准确率和更强的鲁棒性。该方法能够有效应用于矿山和隧道工程领域的岩爆预测。
