In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state（UASS）with anaerobic filter（AF） system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was inves...In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state（UASS）with anaerobic filter（AF） system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0–431 m L O2/gvswere conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431 m L O2/gvsincreased the methane yield by 82.2%. Aeration intensities of 0–355 m L O2/gvswere conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen（DO） of UASS and AF reactors kept around 1.39 ±0.27 and 0.99 ± 0.38 mg/L, respectively. p H was relatively stable around 7.11 ± 0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85 ± 7 m L/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.展开更多
We consider a scenario where an unmanned aerial vehicle(UAV),a typical unmanned aerial system(UAS),transmits confidential data to a moving ground target in the presence of multiple eavesdroppers.Multiple friendly reco...We consider a scenario where an unmanned aerial vehicle(UAV),a typical unmanned aerial system(UAS),transmits confidential data to a moving ground target in the presence of multiple eavesdroppers.Multiple friendly reconfigurable intelligent surfaces(RISs) help to secure the UAV-target communication and improve the energy efficiency of the UAV.We formulate an optimization problem to minimize the energy consumption of the UAV,subject to the mobility constraint of the UAV and that the achievable secrecy rate at the target is over a given threshold.We present an online planning method following the framework of model predictive control(MPC) to jointly optimize the motion of the UAV and the configurations of the RISs.The effectiveness of the proposed method is validated via computer simulations.展开更多
Coastal wetlands,crucial for global biodiversity and climate adaptation,provide essential ecosystem services such as carbon storage and flood protection.These vital areas are increasingly threatened by both natural an...Coastal wetlands,crucial for global biodiversity and climate adaptation,provide essential ecosystem services such as carbon storage and flood protection.These vital areas are increasingly threatened by both natural and human-induced changes,prompting the need for advanced monitoring techniques.This study employs unmanned aerial systems(UASs)equipped with light detection and ranging(LiDAR)and multispectral sensors to survey diverse wetland types across 8 sites in North Carolina.Utilizing high-resolution elevation data and detailed vegetation analysis,coupled with sophisticated machine learning algorithms,we achieved differentiated and highly precise classifications of wetland types.Classification accuracies varied by type,with estuarine intertidal emergent wetlands showing the highest classification accuracies due to less complex vegetation structure and clearer spectral signatures,especially when collections account for tidal influence.In contrast,palustrine forested and scrub-shrub wetlands presented lower accuracies,often due to the denser,mixed,and more complex vegetation structure and variable inundation levels,which complicate spectral differentiation and ground returns from LiDAR sensors.Overall,our integrated UAS-derived LiDAR and multispectral approach not only enhances the accuracy of wetland mapping but also offers a scalable,efficient,and cost-effective method that substantially advances conservation efforts and informs policy-making for coastal resilience.By demonstrating the usefulness of small-scale aerial data collection in ecological mapping,this study highlights the transformative potential of merging advanced technologies in environmental monitoring,underscoring their critical role in sustaining natural habitats and aiding in climate change mitigation strategies.展开更多
Aims Unmanned aerial vehicles(UAVs),i.e.drones,have recently emerged as cost-effective and flexible tools for acquiring remote sensing data with fine spatial and temporal resolution.It provides a new method and opport...Aims Unmanned aerial vehicles(UAVs),i.e.drones,have recently emerged as cost-effective and flexible tools for acquiring remote sensing data with fine spatial and temporal resolution.It provides a new method and opportunity for plant ecologists to study issues from individual to regional scales.However,as a new method,UAVs remote sensing applications in plant ecology are still challenged.The needs of plant ecology research and the application development of UAVs remote sensing should be better integrated.Methods This report provides a comprehensive review of UAV-based remote sensing applications in plant ecology to synthesize prospects of applying drones to advance plant ecology research.Important Findings Of the 400 references,59%were published in remote sensing journals rather than in plant ecology journals,reflecting a substantial gap between the interests of remote sensing experts and plant ecologists.Most of the studies focused on UAV remote sensing’s technical aspects,such as data processing and remote sensing inversion,with little attention on answering ecological questions.There were 61%of studies involved community-scale research.RGB and multispectral cameras were the most used sensors(75%).More ecologically meaningful parameters can be extracted from UAV data to better understand the canopy surface irregularity and community heterogeneity,identify geometrical characteristics of canopy gaps and construct canopy chemical assemblies from living vegetation volumes.More cooperation between plant ecologists and remote sensing experts is needed to promote UAV remote sensing in advancing plant ecology research.展开更多
基金funding from the German Federal Ministry of Education and Research (No. 03SF0381A)the National Natural Science Foundation of China (No. 21206084)the National Key Technology Support Program of China (No. 2014BAC27B01)
文摘In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state（UASS）with anaerobic filter（AF） system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0–431 m L O2/gvswere conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431 m L O2/gvsincreased the methane yield by 82.2%. Aeration intensities of 0–355 m L O2/gvswere conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen（DO） of UASS and AF reactors kept around 1.39 ±0.27 and 0.99 ± 0.38 mg/L, respectively. p H was relatively stable around 7.11 ± 0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85 ± 7 m L/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.
基金funding from the Australian Government,via grant AUSMURIB000001 associated with ONR MURI Grant N00014-19-1-2571。
文摘We consider a scenario where an unmanned aerial vehicle(UAV),a typical unmanned aerial system(UAS),transmits confidential data to a moving ground target in the presence of multiple eavesdroppers.Multiple friendly reconfigurable intelligent surfaces(RISs) help to secure the UAV-target communication and improve the energy efficiency of the UAV.We formulate an optimization problem to minimize the energy consumption of the UAV,subject to the mobility constraint of the UAV and that the achievable secrecy rate at the target is over a given threshold.We present an online planning method following the framework of model predictive control(MPC) to jointly optimize the motion of the UAV and the configurations of the RISs.The effectiveness of the proposed method is validated via computer simulations.
基金North Carolina Department of Transportation(NCDOT),contract number RP 2020-04,awarded to N.G.P.(lead principal investigator)J.N.H.in the Department of Earth and Ocean Sciences at the University of North Carolina Wilmington.
文摘Coastal wetlands,crucial for global biodiversity and climate adaptation,provide essential ecosystem services such as carbon storage and flood protection.These vital areas are increasingly threatened by both natural and human-induced changes,prompting the need for advanced monitoring techniques.This study employs unmanned aerial systems(UASs)equipped with light detection and ranging(LiDAR)and multispectral sensors to survey diverse wetland types across 8 sites in North Carolina.Utilizing high-resolution elevation data and detailed vegetation analysis,coupled with sophisticated machine learning algorithms,we achieved differentiated and highly precise classifications of wetland types.Classification accuracies varied by type,with estuarine intertidal emergent wetlands showing the highest classification accuracies due to less complex vegetation structure and clearer spectral signatures,especially when collections account for tidal influence.In contrast,palustrine forested and scrub-shrub wetlands presented lower accuracies,often due to the denser,mixed,and more complex vegetation structure and variable inundation levels,which complicate spectral differentiation and ground returns from LiDAR sensors.Overall,our integrated UAS-derived LiDAR and multispectral approach not only enhances the accuracy of wetland mapping but also offers a scalable,efficient,and cost-effective method that substantially advances conservation efforts and informs policy-making for coastal resilience.By demonstrating the usefulness of small-scale aerial data collection in ecological mapping,this study highlights the transformative potential of merging advanced technologies in environmental monitoring,underscoring their critical role in sustaining natural habitats and aiding in climate change mitigation strategies.
基金This research was supported by GDAS’(Guangdong Academy of Sciences)Special Project of Science and Technology Development(2020GDASYL-20200301003,2017GDASCX-0805,2020GDASYL-040101,2020GDASYL-20200102001)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA13020506)+1 种基金Science and Technology Projects of Guangdong Province(2017A020216022,2018B030324002)the National Natural Science Foundation of China(31770473).
文摘Aims Unmanned aerial vehicles(UAVs),i.e.drones,have recently emerged as cost-effective and flexible tools for acquiring remote sensing data with fine spatial and temporal resolution.It provides a new method and opportunity for plant ecologists to study issues from individual to regional scales.However,as a new method,UAVs remote sensing applications in plant ecology are still challenged.The needs of plant ecology research and the application development of UAVs remote sensing should be better integrated.Methods This report provides a comprehensive review of UAV-based remote sensing applications in plant ecology to synthesize prospects of applying drones to advance plant ecology research.Important Findings Of the 400 references,59%were published in remote sensing journals rather than in plant ecology journals,reflecting a substantial gap between the interests of remote sensing experts and plant ecologists.Most of the studies focused on UAV remote sensing’s technical aspects,such as data processing and remote sensing inversion,with little attention on answering ecological questions.There were 61%of studies involved community-scale research.RGB and multispectral cameras were the most used sensors(75%).More ecologically meaningful parameters can be extracted from UAV data to better understand the canopy surface irregularity and community heterogeneity,identify geometrical characteristics of canopy gaps and construct canopy chemical assemblies from living vegetation volumes.More cooperation between plant ecologists and remote sensing experts is needed to promote UAV remote sensing in advancing plant ecology research.
