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Characterization of spray deposition and drift from a low drift nozzle for aerial application at different application altitudes

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International journal of Agricultural and Biological Engineering 2011年第4期4卷 28-33页

作者： Yanbo Huang steven j.thomson US Department of Agriculture Agricultural Research ServiceCrop Production Systems Research UnitStonevilleMS 38776USA

A complex interaction of controllable and uncontrollable factors is involved in aerial application of crop production and protection *** it is difficult to completely characterize spray deposition and drift,these important factors can be estimated with appropriate sampling protocol and *** height is an important variable influencing off-target spray drift,but this variable has not been easily measured or logged.A custom-configured aircraft-mounted laser with logging capabilities makes this *** study was designed to investigate droplet size and deposition characteristics of a low drift CP flat-fan nozzle at application altitudes 3.7 m,4.9 m,and 6.1 *** the study,CP flat-fan nozzles were set to a downward angle of 30 degrees applying a mixture of water,Syl-Tac®adjuvant,and Rubidium Chloride(RbCl)tracer at a 28.5 L/ha application *** droplets were collected using water sensitive paper(WSP)cards placed in the spray *** sheets were also placed in the swath and downwind for drift *** analysis indicated that median droplet diameter as determined by WSP in the spray swath was not significantly influenced by spray application ***,statistical analysis also indicated that concentration of RbCl tracer from Mylar samplers in the spray swath was not significantly influenced by application *** height had a significant effect on spray deposition from drift samplers,along with wind direction and relative *** results for drift samplers may have been influenced by shifts in wind direction that altered the relationship between orientation of samplers and wind.

关键词： deposition spray nozzle aerial application droplet spectra spray drift

Estimation of cotton yield with varied irrigation and nitrogen treatments using aerial multispectral imagery

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International journal of Agricultural and Biological Engineering 2013年第2期6卷 37-41页

作者： Yanbo Huang Ruixiu Sui steven j.thomson Daniel K.Fisher Crop Production Systems Research Unit Agricultural Research ServiceUnited States Department of AgricultureStonevilleMS 38776USA

Cotton yield varies spatially within a *** variability can be caused by various production inputs such as soil properties,water management,and fertilizer *** multispectral imaging is capable of providing data and information to study effects of the inputs on yield qualitatively and quantitatively in a timely and cost-effective fashion.A 10-ha cotton field with irrigation and non-irrigation 2×2 blocks was used in this *** nitrogen application treatments were randomized with two replications within each *** plant canopy was closed,airborne multispectral images of the field were acquired using a 3-CCD MS4100 *** images were processed to generate various vegetation *** vegetation indices were evaluated for the best performance to characterize *** effect of irrigation on vegetation indices was *** for yield estimation were developed and verified by comparing the estimated and actual *** indicated that ratio of vegetation index(RVI)had a close relationship with yield(R^(2)=0.47).Better yield estimation could be obtained using a model with RVI and soil electrical conductivity(EC)measurements of the field as explanatory variables(R^(2)=0.53).This research demonstrates the capability of aerial multispectral remote sensing in estimating cotton yield variation and considering soil properties and nitrogen.

关键词： remote sensing multispectral imagery cotton yield nitrogen irrigation soil properties

Ground-based hyperspectral remote sensing for weed management in crop production

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International journal of Agricultural and Biological Engineering 2016年第2期9卷 98-109页

作者： Yanbo Huang Matthew A.Lee steven j.thomson Krishna N.Reddy United States Department of Agriculture Agricultural Research ServiceCrop Production Systems Research UnitPO Box 350Stoneville MS 38776USA Department of Electrical and Computer Engineering Mississippi State UniversityMississippi State MS 39762USA United States Department of Agriculture National Institute of Food and AgricultureWashington DC 20024USA

Agricultural remote sensing has been developed and applied in monitoring soil,crop growth,weed infestation,insects,diseases and water status in farm fields to provide data and information to guide agricultural management *** agriculture has been implemented through prescription mapping of crop fields at different scales with the data remotely sensed from space-borne,airborne and ground-based ***-based remote sensing techniques offer portability,flexibility and controllability in applications for precision *** weed management,crop injury from off-target herbicide spray drift and herbicide resistance in weeds are two important *** precision weed management,ground-based hyperspectral remote sensing techniques were developed for detection of crop injury from dicamba and differentiation between glyphosate resistant and sensitive *** research presents the techniques for ground-based hyperspectral remote sensing for these two *** illustrate the advantages of ground-based hyperspectral remote sensing for precision weed management.

关键词： ground-based remote sensing hyperspectral crop injury herbicide resistance precision agriculture

Development and evaluation of low-altitude remote sensing systems for crop production management

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International journal of Agricultural and Biological Engineering 2016年第4期9卷 1-11页

作者： Yanbo Huang steven j.thomson Howard j.Brand Krishna N.Reddy United States Department of Agriculture Agricultural Research ServiceCrop Production Systems Research UnitStoneville 38776USA United States Department of Agriculture National Institute of Food and AgricultureDivision of Agricultural SystemsWashington DC 20024USA Virginia Tech Department of Mechanical EngineeringBlacksburg 24061USA

Precision agriculture accounts for within-field variability for targeted treatment rather than uniform treatment of an entire *** is built on agricultural mechanization and state-of-the-art technologies of geographical information systems(GIS),global positioning systems(GPS)and remote sensing,and is used to monitor soil,crop growth,weed infestation,insects,diseases,and water status in farm fields to provide data and information to guide agricultural management *** agriculture began with mapping of crop fields at different scales to support agricultural planning and decision *** the development of variable-rate technology,precision agriculture focuses more on tactical actions in controlling variable-rate seeding,fertilizer and pesticide application,and irrigation in real-time or within the crop season instead of mapping a field in one crop season to make decisions for the next crop *** the development of aerial variable-rate systems,low-altitude airborne systems can provide high-resolution data for prescription variable-rate *** systems for multispectral imaging using a number of imaging sensors(cameras)were *** aerial vehicles(UAVs)provide a unique platform for remote sensing of crop fields at slow speeds and low-altitudes,and they are efficient and more flexible than manned agricultural airplanes,which often cannot provide images at both low altitude and low speed for capture of high-quality *** are also more universal in their applicability than agricultural aircraft since the latter are used only in specific *** study presents the low-altitude remote sensing systems developed for detection of crop stress caused by multiple ***,as a special platform,were discussed for crop sensing based on the researchers'studies.

关键词： low-altitude remote sensing agricultural airplane unmanned aerial vehicle(UAV) crop production management precision agriculture

Development and prospect of unmanned aerial vehicle technologies for agricultural production management

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International journal of Agricultural and Biological Engineering 2013年第3期6卷 1-10页

作者： Yanbo Huang steven j.thomson W.Clint Hoffmann Yubin Lan Bradley K.Fritz United States Department of Agriculture Agricultural Research ServiceCrop Production Systems Research UnitStonevilleMS 38776USA United States Department of Agriculture Agricultural Research ServiceAreawide Pest Management Research UnitCollege StationTX 77845USA

Unmanned aerial vehicles have been developed and applied to support agricultural production *** with piloted aircraft,an Unmanned Aerial Vehicle(UAV)can focus on small crop fields at lower flight altitudes than regular aircraft to perform site-specific farm management with higher *** can also“fill in the gap”in locations where fixed winged or rotary winged aircraft are not readily *** agriculture,UAVs have primarily been developed and used for remote sensing and application of crop production and protection *** of fertilizers and chemicals is frequently needed at specific times and locations for site-specific *** monitoring of crop plant health is often required at very high resolution for accurate site-specific management as *** paper presents an overview of research involving the development of UAV technology for agricultural production ***,systems and methods are examined and *** limitations of current UAVs for agricultural production management are discussed,as well as future needs and suggestions for development and application of the UAV technologies in agricultural production management.

关键词： unmanned aerial vehicle aircraft aerial application technology sensor remote sensing precision agriculture agricultural aviation

Characterizing downwind drift deposition of aerially applied glyphosate using RbCl as tracer

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International journal of Agricultural and Biological Engineering 2017年第3期10卷 31-36页

作者： Yanbo Huang Claudiane M.Ouellet-Plamondon steven j.thomson Krishna N.Reddy United States Department of Agriculture Agricultural Research ServiceCrop Production Systems Research Unit141 Experiment Station RoadStonevilleMS 38776USA Department of Construction Engineering Superior Technology School1100 Notre-Dame Street WestMontrealQuebec H3C 1K3Canada United States Department of Agriculture National Institute of Food and AgriculturalDivision of Agricultural SystemsWaterfront Center80009th StreetSWWashingtonDC 20024USA

Rubidium chloride(RbCl)was used as a tracer tank-mixed with active ingredients to profile downwind deposition of aerially applied crop protection and production materials to characterize off-target drift,which helps improve spray efficiency and reduce environmental *** sheets were placed on a holder in the field at each sampling station to collect sprayed *** tracer was used to assess downwind drift of nozzles mounted on the booms installed and controlled on both sides of an agricultural *** experiment was conducted on a field covered by Bermuda grass(Cynodon dactylon).During the experiment,the airplane was planned to fly three passes with three replications at each of three different altitudes,3.7 m,4.9 m,and 6.1 m for total of 27 flight *** results indicated that sampling station location had a significant effect on RbCl ***,application release altitude was not significant to the change of *** practical application in the same aerial application system was used to assess crop injury from the off-target drift of aerially applied *** concentrations measured from Mylar sheets were correlated with visual injury,plant height,shoot dry weight,leaf chlorophyll content,and shikimate,which were measured from the leaves and plant samples ***,RbCl is an effective tracer for monitoring spray applications from agricultural aircraft and unmanned aerial vehicles to intensify agriculture output and minimize environmental impact.

关键词： Rubidium chloride(RbCl) precision agriculture spray efficiency off-target drift aerial application herbicide crop injury environmental pollution

Multispectral imaging systems for airborne remote sensing to support agricultural production management

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International journal of Agricultural and Biological Engineering 2010年第1期3卷 50-62页

作者： Yanbo Huang steven j.thomson Yubin Lan Stephan j.Maas USDA-ARS Crop Production Systems Research Unit StonevilleMS 38776USA USDA ARS Areawide Pest Management Research Unit College StationTX 77845USA Texas Tech University LubbockTX 79409USA

This study investigated three different types of multispectral imaging systems for airborne remote sensing to support management in agricultural application and *** three systems have been used in agricultural *** range from low-cost to relatively high-cost,manually operated to automated,multispectral composite imaging with a single camera and integrated imaging with custom-mounting of separate *** issues regarding use of the imaging systems were described and *** low-cost system,due to band saturation,slow imaging speed and poor image quality,is more preferable to slower moving platforms that can fly close to the ground,such as unmanned autonomous helicopters,but not recommended for low or high altitude aerial remote sensing on fixed-wing *** the restriction on payload unmanned autonomous helicopters are not recommended for high-cost systems because they are typically heavy and difficult to *** system with intermediate cost works well for low altitude aerial remote sensing on fixed-wing aircraft with field shapefile-based global positioning *** system also works well for high altitude aerial remote sensing on fixed-wing aircraft with global positioning triggering or manually *** custom-built system is recommended for high altitude aerial remote sensing on fixed-wing aircraft with waypoint global positioning triggering or manually operated.

关键词： airborne remote sensing multispectral imaging agricultural production management

Universal silicon ring resonator for error-free transmission links

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Photonics Research 2024年第4期12卷 701-711页

作者： jUNBO ZHU WEIWEI ZHANG KE LI BHARAT PANT MARTIN EBERT XINGZHAO YAN MEHDI BANAKAR DEHN T.TRAN CALLUM G.LITTLEjOHNS FUWAN GAN GRAHAM REED DAVID j.thomson Optoelectronics Research Centre University of SouthamptonSouthampton SO171BJUK National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China University of Chinese Academy of Sciences Beijing 100049China Peng Cheng Laboratory ShenzhenChina

We report the design, fabrication, and characterization of a universal silicon PN junction ring resonator for C band error-free communication links operated up to 50 Gb/s with co-designed optical modulation and detection performance. The universal p-n junction ring device shows co-designed detection responsivity up to 0.84 A/W, in conjunction with a modulation efficiency of -4 V·mm and>8 d B optical modulation extinction ratio, enabling C band 50 Gb/s NRZ communication link with a bit error rate≤3×10^(-12).

关键词： Gb/s resonator communication

High-speed silicon photonic electro-optic Kerr modulation

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Photonics Research 2024年第1期12卷 51-60页

作者： jONATHAN PELTIER WEIWEI ZHANG LEOPOLD VIROT CHRISTIAN LAFFORGUE LUCAS DENIEL DELPHINE MARRIS-MORINI GUY AUBIN FARAH AMAR DENH TRAN XINGZHAO YAN CALLUM G.LITTLEjOHNS CARLOS ALONSO-RAMOS KE LI DAVID j.thomson GRAHAM REED LAURENT VIVIEN University Paris-Saclay CNRSCentre for Nanoscience and Nanotechnology(C2N)Palaiseau 91120France University Grenoble Alpes CEALETIGrenoble 38000France Optoelectronics Research Centre Zepler Institute for Photonics and NanoelectronicsFaculty of Engineering and Physical SciencesUniversity of SouthamptonSouthampton SO171BJUK

Silicon-based electro-optic modulators contribute to easing the integration of high-speed and low-power consumption circuits for classical optical communications and data *** the plasma dispersion modulation,an alternative solution in silicon is to exploit the DC Kerr effect,which generates an equivalent linear electro-optical effect enabled by applying a large DC electric *** some theoretical and experimental studies have shown its existence in silicon,limited contributions relative to plasma dispersion have been achieved in high-speed modulation so *** paper presents high-speed optical modulation based on the DC Kerr effect in silicon PIN *** contributions of both plasma dispersion and Kerr effects have been analyzed in different waveguide configurations,and we demonstrated that the Kerr induced modulation is dominant when a high external DC electric field is applied in PIN ***-speed optical modulation response is analyzed,and eye diagrams up to 80 Gbit/s in NRZ format are obtained under a *** of 30 *** work paves the way to exploit the Kerr effect to generate high-speed Pockels-like optical modulation.

关键词： waveguide dispersion effect