[目的]西南喀斯特区土壤侵蚀问题十分突出,严重影响着区域社会经济的可持续发展。而喀斯特流域特征环境因子如何影响土壤侵蚀的直接驱动力—径流侵蚀力,目前尚不十分明晰。[方法]以西南喀斯特地区的野纪河流域为例,基于流域出口水文站...[目的]西南喀斯特区土壤侵蚀问题十分突出,严重影响着区域社会经济的可持续发展。而喀斯特流域特征环境因子如何影响土壤侵蚀的直接驱动力—径流侵蚀力,目前尚不十分明晰。[方法]以西南喀斯特地区的野纪河流域为例,基于流域出口水文站长系列高频实测数据,采用水土评估工具(SWAT)和偏最小二乘模型(PLSR)评估了2005—2020年流域径流侵蚀力的时空演变特征,解析了主要喀斯特环境因子对径流侵蚀力的影响。[结果]流域多年平均径流侵蚀力为2326.47 m ^(4)/(km ^(2)·s),并具有较强的空间异质性,2005年径流侵蚀力高值主要分布北部和中部,而2010—2020年,径流侵蚀力高值区逐步向中南部转移。时间上,受益于岩溶区“十一五”以来坡耕地水土流失综合治理、石漠化综合治理等生态修复工程的实施,野纪河流域径流侵蚀力总体上呈降低趋势。岩性、基岩裸露、坡度是影响野纪河流域径流侵蚀力变化的主导控制因子,对径流侵蚀力时空分异的共同解释度达57.7%。[结论]研究结果可为喀斯特流域水侵蚀导致的水土流失综合防治提供理论参考,有助于制定更加精准和有效的政策和措施,改善喀斯特区生态环境,促进该地区的可持续发展。展开更多
Here we demonstrate the proof-of-concept for microchannel reactive distillation for alcohol-to-jet application:combining ethanol/water separation and ethanol dehydration in one unit operation.Ethanol is first distille...Here we demonstrate the proof-of-concept for microchannel reactive distillation for alcohol-to-jet application:combining ethanol/water separation and ethanol dehydration in one unit operation.Ethanol is first distilled into the vapor phase,converted to ethylene and water,and then the water co-product is condensed to shift the reaction equilibrium.Process intensification is achieved through rapid mass transfer-ethanol stripping from thin wicks using novel microchannel architectures-leading to lower residence time and improved separation efficiency.Energy savings are realized with integration of unit operations.For example,heat of condensing water can offset vaporizing ethanol.Furthermore,the dehydration reaction equilibrium shifts towards completion by immediate removal of the water byproduct upon formation while maintaining aqueous feedstock in the condensed phase.For aqueous ethanol feedstock(40%_w),71% ethanol conversion with 91% selectivity to ethylene was demonstrated at 220℃,600psig,and 0.28 h^(-1) wt hour space velocity.2.7 stages of separation were also demonstrated,under these conditions,using a device length of 8.3 cm.This provides a height equivalent of a theoretical plate(HETP),a measure of separation efficiency,of ^(3).3 cm.By comparison,conventional distillation packing provides an HETP of ^(3)0 cm.Thus,9,1 × reduction in HETP was demonstrated over conventional technology,providing a means for significant energy savings and an example of process intensification.Finally,preliminary process economic analysis indicates that by using microchannel reactive distillation technology,the operating and capital costs for the ethanol separation and dehydration portion of an envisioned alcoholto-jet process could be reduced by at least 35% and 55%,respectively,relative to the incumbent technology,provided future improvements to microchannel reactive distillation design and operability are made.展开更多
Adventitious rooting(AR)is critical to the propagation,breeding,and genetic engineering of trees.The capacity for plants to undergo this process is highly heritable and of a polygenic nature;however,the basis of its g...Adventitious rooting(AR)is critical to the propagation,breeding,and genetic engineering of trees.The capacity for plants to undergo this process is highly heritable and of a polygenic nature;however,the basis of its genetic variation is largely uncharacterized.To identify genetic regulators of AR,we performed a genome-wide association study(GWAS)using 1148 genotypes of Populus trichocarpa.GWASs are often limited by the abilities of researchers to collect precise phenotype data on a high-throughput scale;to help overcome this limitation,we developed a computer vision system to measure an array of traits related to adventitious root development in poplar,including temporal measures of lateral and basal root length and area.GWAS was performed using multiple methods and significance thresholds to handle non-normal phenotype statistics and to gain statistical power.These analyses yielded a total of 277 unique associations,suggesting that genes that control rooting include regulators of hormone signaling,cell division and structure,reactive oxygen species signaling,and other processes with known roles in root development.Numerous genes with uncharacterized functions and/or cryptic roles were also identified.These candidates provide targets for functional analysis,including physiological and epistatic analyses,to better characterize the complex polygenic regulation of AR.展开更多
文摘[目的]西南喀斯特区土壤侵蚀问题十分突出,严重影响着区域社会经济的可持续发展。而喀斯特流域特征环境因子如何影响土壤侵蚀的直接驱动力—径流侵蚀力,目前尚不十分明晰。[方法]以西南喀斯特地区的野纪河流域为例,基于流域出口水文站长系列高频实测数据,采用水土评估工具(SWAT)和偏最小二乘模型(PLSR)评估了2005—2020年流域径流侵蚀力的时空演变特征,解析了主要喀斯特环境因子对径流侵蚀力的影响。[结果]流域多年平均径流侵蚀力为2326.47 m ^(4)/(km ^(2)·s),并具有较强的空间异质性,2005年径流侵蚀力高值主要分布北部和中部,而2010—2020年,径流侵蚀力高值区逐步向中南部转移。时间上,受益于岩溶区“十一五”以来坡耕地水土流失综合治理、石漠化综合治理等生态修复工程的实施,野纪河流域径流侵蚀力总体上呈降低趋势。岩性、基岩裸露、坡度是影响野纪河流域径流侵蚀力变化的主导控制因子,对径流侵蚀力时空分异的共同解释度达57.7%。[结论]研究结果可为喀斯特流域水侵蚀导致的水土流失综合防治提供理论参考,有助于制定更加精准和有效的政策和措施,改善喀斯特区生态环境,促进该地区的可持续发展。
基金financially U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Bioenergy Technologies Office, and the Office of Technology Transitions Technology Commercialization FundFinancial support also was provided by Lanza Tech through a Cooperative Research and Development Agreement。
文摘Here we demonstrate the proof-of-concept for microchannel reactive distillation for alcohol-to-jet application:combining ethanol/water separation and ethanol dehydration in one unit operation.Ethanol is first distilled into the vapor phase,converted to ethylene and water,and then the water co-product is condensed to shift the reaction equilibrium.Process intensification is achieved through rapid mass transfer-ethanol stripping from thin wicks using novel microchannel architectures-leading to lower residence time and improved separation efficiency.Energy savings are realized with integration of unit operations.For example,heat of condensing water can offset vaporizing ethanol.Furthermore,the dehydration reaction equilibrium shifts towards completion by immediate removal of the water byproduct upon formation while maintaining aqueous feedstock in the condensed phase.For aqueous ethanol feedstock(40%_w),71% ethanol conversion with 91% selectivity to ethylene was demonstrated at 220℃,600psig,and 0.28 h^(-1) wt hour space velocity.2.7 stages of separation were also demonstrated,under these conditions,using a device length of 8.3 cm.This provides a height equivalent of a theoretical plate(HETP),a measure of separation efficiency,of ^(3).3 cm.By comparison,conventional distillation packing provides an HETP of ^(3)0 cm.Thus,9,1 × reduction in HETP was demonstrated over conventional technology,providing a means for significant energy savings and an example of process intensification.Finally,preliminary process economic analysis indicates that by using microchannel reactive distillation technology,the operating and capital costs for the ethanol separation and dehydration portion of an envisioned alcoholto-jet process could be reduced by at least 35% and 55%,respectively,relative to the incumbent technology,provided future improvements to microchannel reactive distillation design and operability are made.
文摘Adventitious rooting(AR)is critical to the propagation,breeding,and genetic engineering of trees.The capacity for plants to undergo this process is highly heritable and of a polygenic nature;however,the basis of its genetic variation is largely uncharacterized.To identify genetic regulators of AR,we performed a genome-wide association study(GWAS)using 1148 genotypes of Populus trichocarpa.GWASs are often limited by the abilities of researchers to collect precise phenotype data on a high-throughput scale;to help overcome this limitation,we developed a computer vision system to measure an array of traits related to adventitious root development in poplar,including temporal measures of lateral and basal root length and area.GWAS was performed using multiple methods and significance thresholds to handle non-normal phenotype statistics and to gain statistical power.These analyses yielded a total of 277 unique associations,suggesting that genes that control rooting include regulators of hormone signaling,cell division and structure,reactive oxygen species signaling,and other processes with known roles in root development.Numerous genes with uncharacterized functions and/or cryptic roles were also identified.These candidates provide targets for functional analysis,including physiological and epistatic analyses,to better characterize the complex polygenic regulation of AR.
