Extensive experimental studies on the heat transfer characteristics of two rows of aligned jet holes impinging on a concave surface in a wing leading edge were conducted, where50000 Rej 90000, 1.74 H/d 27.5, 66° ...Extensive experimental studies on the heat transfer characteristics of two rows of aligned jet holes impinging on a concave surface in a wing leading edge were conducted, where50000 Rej 90000, 1.74 H/d 27.5, 66° a 90°, and 13.2 r/d 42.03. The finding was that the heat transfer performance at the jet-impingement stagnation point with two rows of aligned jet holes was the same as that with a single row of jet holes or the middle row of three-row configurations when the circumferential angle of the two jet holes was larger than 30°. The attenuation coefficient distribution of the jet impingement heat transfer in the chordwise direction was so complicated that two zones were divided for a better analysis. It indicated that： the attenuation coefficient curve in the jet impingement zone exhibited an approximate upside-down bell shape with double peaks and a single valley; the attenuation coefficient curve in the non-jet impingement zone was like a half-bell shape, which was similar to that with three rows of aligned jet holes; the factors,including Rej, H/d and r/d, affected the attenuation coefficient value at the valley significantly.When r/d was increased from 30.75 to 42.03, the attenuation rates of attenuation coefficient increased only by 1.8%. Consequently, experimental data-based correlation equations of the Nusselt number for the heat transfer at the jet-impingement stagnation point and the distributionof the attenuation coefficient in the chordwise direction were acquired, which play an important role in designing the wing leading edge anti-icing system with two rows of aligned jet holes.展开更多
China is one of the world's largest agricultural countries, planting a variety of crops, and maize is one of which has a relatively large planting area and is an important food and commercial crop. With the develo...China is one of the world's largest agricultural countries, planting a variety of crops, and maize is one of which has a relatively large planting area and is an important food and commercial crop. With the development of agricultural modernization, the high-yield planting technology of maize has been in continuous research and development, among which many advanced technologies have been applied. Wide-narrow row alternate planting is one of the more representative ones, and its application scope is very wide. Almost all planting areas of maize are adopting it, which has made an important contribution to the improvement of high-yield and quality of maize. In this paper, the application of maize's wide and narrow row alternate planting technology is analyzed in depth.展开更多
Paddy field management is complicated and labor intensive.Correct row detection is important to automatically track rice rows.In this study,a novel method was proposed for accurate rice row recognition in paddy field ...Paddy field management is complicated and labor intensive.Correct row detection is important to automatically track rice rows.In this study,a novel method was proposed for accurate rice row recognition in paddy field transplanted by machine before the disappearance of row information.Firstly,Bayesian decision theory based on the minimum error was used to classify the period of collected images into three periods(T1:0-7 d;T2:7-28 d;T3:28-45 d),and resulting in the correct recognition rate was 97.03%.Moreover,secondary clustering of feature points was proposed,which can solve some problems such as row breaking and tilting.Then,the robust regression least squares method(RRLSM)for linear fitting was proposed to fit rice rows to effectively eliminate interference by outliers.Finally,a credibility analysis of connected region markers was proposed to evaluate the accuracy of fitting lines.When the threshold of credibility was set at 40%,the correct recognition rate of fitting lines was 96.32%.The result showed that the method can effectively solve the problems caused by the presence of duckweed,high-density inter-row weeds,broken rows,tilting(±60°),wind and overlap.展开更多
Crop rows detection in maize fields remains a challenging problem due to variation in illumination and weeds interference under field conditions.This study proposed an algorithm for detecting crop rows based on adapti...Crop rows detection in maize fields remains a challenging problem due to variation in illumination and weeds interference under field conditions.This study proposed an algorithm for detecting crop rows based on adaptive multi-region of interest(multi-ROI).First,the image was segmented into crop and soil and divided into several horizontally labeled strips.Feature points were located in the first image strip and initial ROI was determined.Then,the ROI window was shifted upward.For the next image strip,the operations for the previous strip were repeated until multiple ROIs were obtained.Finally,the least square method was carried out to extract navigation lines and detection lines in multi-ROI.The detection accuracy of the method was 95.3%.The average computation time was 240.8 ms.The results suggest that the proposed method has generally favorable performance and can meet the real-time and accuracy requirements for field navigation.展开更多
Sugarcane planting is an important and growing activity in Brazil.Thereupon,several techniques have been developed over the years to maximize crop productivity and profit,amongst them,processing of sugarcane field ima...Sugarcane planting is an important and growing activity in Brazil.Thereupon,several techniques have been developed over the years to maximize crop productivity and profit,amongst them,processing of sugarcane field images.In this sense,this research aims to identify and analyze crop rows and measure their gaps from aerial images of sugarcane fields.For this,a small Remotely Piloted Aircraft captured the images,generating orthomosaics of the areas for analysis.Then,each orthomosaic is classified with the K-Nearest Neighbor algorithm to segment regions of interest.Planting row orientation is estimated using the RGB gradient filter.Morphological operations and computational geometry models are then used to detect and map rows and gaps along the planting row segment.To evaluate the results,crop rows are mapped and compared to manually taken measurements.Our technique obtained an error smaller than 2%when compared to gap length in crop rows from an orthomosaic with the area of 8.05 ha(ha).The proposed approach can map the positioning of the automatically generated row segments appropriately onto manually created segments.Moreover,our method also achieved similar results when confronted with a manual technique for differing growth stages(40 and 80 days after harvest)of the sugarcane crop.The proposed method presents a great potential to be adopted in sugarcane planting monitoring。展开更多
Rice leaf morphology is of great significance in the breeding of an ideal plant type and high photosynthetic efficiency.A forward genetics approach was employed to locate a novel gene,NRL9(NARROW AND ROLLED LEAF 9).NR...Rice leaf morphology is of great significance in the breeding of an ideal plant type and high photosynthetic efficiency.A forward genetics approach was employed to locate a novel gene,NRL9(NARROW AND ROLLED LEAF 9).NRL9 encodes a 20S proteasome β1 subunit and is involved in regulating leaf morphology and grain size.Compared with the wild type(WT),the nrl9 mutant exhibited a significant decrease in leaf width,and a significant increase in leaf rolling index(LRI),while also displaying increased grain length and decreased grain width.展开更多
[Objectives]To provide a reference for the promotion of appropriate row spacing configuration modes for cotton planting in the Bortala Mongol Autonomous Prefecture of Xinjiang.[Methods]Xinluzao 63 was employed as the ...[Objectives]To provide a reference for the promotion of appropriate row spacing configuration modes for cotton planting in the Bortala Mongol Autonomous Prefecture of Xinjiang.[Methods]Xinluzao 63 was employed as the research subject to examine the effects of three different configuration modes:three rows with one film,four rows with one film,and six rows with one film,on the growth and development of cotton,as well as on yield and the amount of residual film in the field.[Results]In comparison to the configuration modes of four rows with one film and six rows with one film,the development process in the row spacing configuration mode of three rows with one film was accelerated by 1-4 d.This configuration mode exhibited variability in several agronomic traits,particularly in plant height,the number of fruiting branches per plant,and the number of leaves per plant,with the observed trend indicating T3>T2>T1.Conversely,the height of the first fruiting branch node displayed an inverse trend.In terms of yield composition,no significant differences were observed in boll weight and yield among various configuration modes.However,T3 exhibited the highest boll weight at 5.68 g and a yield of 462.67 kg/667 m 2.Additionally,significant differences were noted in harvesting density and the number of bolls per plant.T3 demonstrated the lowest harvesting density at 1.11×104 plants/666.7 m 2,the highest number of bolls per plant at 8.63,and the highest boll opening rate at 97.48%.Furthermore,T3 also resulted in the least amount of agricultural film residue during the current season.[Conclusions]Among the three planting configuration modes examined,the low-density planting configuration mode consisting of three rows and one film demonstrated a significant advantage at the individual plant level.This approach yielded results comparable to those of the high density planting configuration mode while also reducing costs.Furthermore,low density planting positively influenced the cotton boll opening rate,leading to a decreased amount of residual film and promoting ecological health within the agricultural land.展开更多
This paper describes the numerical simulation of three-dimensional viscous flows in fir-cooled turbine blade rows with the effects of coolant ejection. A TVD Navier-Stokes flow solver incorporated with Baldwin-Lomax t...This paper describes the numerical simulation of three-dimensional viscous flows in fir-cooled turbine blade rows with the effects of coolant ejection. A TVD Navier-Stokes flow solver incorporated with Baldwin-Lomax turbulence model and multi-grid convergence acceleration algorithm are used for the simulation. The influences of coolant ejection on the main flow are accounted by volumetric coolant source terms. Numerical results for a four-stage turbine are presented and discussed.展开更多
Climate change and extreme weather pose significant challenges to the traditional viticulture regions.Emerging high-altitude grape-producing regions with diverse orientations have shown great potential in coping with ...Climate change and extreme weather pose significant challenges to the traditional viticulture regions.Emerging high-altitude grape-producing regions with diverse orientations have shown great potential in coping with this challenge.Stable,high-quality wine grape production may be achieved by synchronizing the meso-and microclimate.To clarify the role of high altitude and row orientation in meso-and microclimate and the response of berries to it,we evaluated seven years(2012-2018)of climate data,two years of basic grape(Cabernet Sauvignon,Vitis vinifera L.)quality,and one-year microclimate from veraison to harvest.By comparing two locations(Sidon 2047 m,Sinon 2208 m)in Yunnan Province,China,we found that the average temperature has been stable at approximately 15℃ for seven years,with no extreme weather or,noticeable global warming.The light intensity(LI)in the north-south(NS)was more balanced than the east-west(EW)direction,and the east-west to the south(EW-S)canopy side was almost higher than the other sides.High LI was associated with high photosynthetically active radiation(PAR),ultraviolet(UV),and infrared(IR)light and vice versa.The north-south to the east(NS-E)and east-west to the north(EWN)sides were characterized by lower LI and higher UV and IR light,and higher total anthocyanin content.Most anthocyanin synthesis-related genes,for example,VvF3'H and VvF3'5'H,were highly expressed in NS-E from veraison to maturity.Perhaps UV and IR light induced their expression.This study provides new insights on the role of differently orientated rows in controlling grape quality due to varied light quality.The findings are globally significant,particularly in the context of climate change,and offer fresh insights into berry physiological responses and decision-making for the management of existing vineyards.展开更多
Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considere...Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considered a replacement for the current Indian production system.It is also suitable for mechanical harvesting,which reducing labour costs,increasing input use efficiency,timely harvesting timely,maintaining cotton quality,and offering the potential to increase productivity and profitability.This technology has become widespread in globally cotton growing regions.Water management is critical for the success of high density cotton planting.Due to the problem of freshwater availability,more crops should be produced per drop of water.In the high-density planting system,optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs.Deficit irrigation is a tool to save water without compromising yield.At the same time,it consumes less water than the normal evapotranspiration of crops.This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation.Based on the current research and combined with cotton production reality,this review discusses the application and future development of deficit irrigation,which may provide theoretical guidance for the sustainable advancement of cotton planting systems.展开更多
[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under c...[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under challenging conditions,such as strong light exposure and weed interference.The aims are to develop an effective crop line extraction method by combining YOLOv8-G,Affinity Propagation,and the Least Squares method to enhance detection accuracy and performance in complex field environments.[Methods]The proposed method employs machine vision techniques to address common field challenges.YOLOv8-G,an improved object detection algorithm that combines YOLOv8 and Ghost‐NetV2 for lightweight,high-speed performance,was used to detect the central points of crops.These points were then clustered using the Affinity Propagation algorithm,followed by the application of the Least Squares method to extract the crop lines.Comparative tests were conducted to evaluate multiple backbone networks within the YOLOv8 framework,and ablation studies were performed to validate the enhancements made in YOLOv8-G.[Results and Discussions]The performance of the proposed method was compared with classical object detection and clustering algorithms.The YOLOv8-G algorithm achieved average precision(AP)values of 98.22%,98.15%,and 97.32%for corn detection at 7,14,and 21 days after emergence,respectively.Additionally,the crop line extraction accuracy across all stages was 96.52%.These results demonstrate the model's ability to maintain high detection accuracy despite challenging conditions in the field.[Conclusions]The proposed crop line extraction method effectively addresses field challenges such as lighting and weed interference,enabling rapid and accurate crop identification.This approach supports the automatic navigation of agricultural machinery,offering significant improvements in the precision and efficiency of field operations.展开更多
Motivated by a critical issue of airline planning process,this paper addresses a new two-stage scenario-based robust optimization in operational airline planning to cope with uncertainty and possible flight disruption...Motivated by a critical issue of airline planning process,this paper addresses a new two-stage scenario-based robust optimization in operational airline planning to cope with uncertainty and possible flight disruptions.Following the route network scheme and generated flight timetables,aircraft maintenance routing and crew scheduling are critical factors in airline planning and operations cost management.This study considers the simultaneous assignment of aircraft fleet and crew to the scheduled flight while satisfying a set of operational constraints,rules,and regulations.Considering multiple locations for airline maintenance and crew bases,we solve the problem of integrated Aircraft Maintenance Routing and Crew Rostering(AMRCR)to achieve the minimum airline cost.One real challenge to the efficiency of the planning results is the possible disruptions in the initial scheduled flights.Due to the fact that disruption scenarios are expressed discretely with a specified probability,and we provide adjustable decisions under disruption to deal with this disruption risk,we provide a Two-Stage Scenario-Based Robust Optimization(TSRO)model.In this model,here-and-now or first-stage variables are the initial resource assignment.Furthermore,to adapt itself to different disruption scenarios,the model considers some adjustable variables,such as the decision to cancel the flight in case of disruption,as wait-and-see or second-stage variables.Considering the complexity of integrated models,and the scenario-based decomposable structure of the TRSO model to solve it with better computational performance,we apply the column and row generation(CRG)method that iteratively considers the disruption scenarios.The numerical results confirm the applicability of the proposed TSRO model in providing the AMRCR problem with an integrated and robust solution with an acceptable level of computational tractability.To evaluate the proposed TSRO model,which solves the AMRCR problem in an integrated and robust manner,five Key Performance Indicators(KPIs)like Number of delayed/canceled flights,Average delay time,and Average profit are taken into account.As key results driven by conducting a case study,we show the proposed TSRO model has substantially improved the solutions at all indicators compared with those of the sequential/non-integrated and nominal/non-robust models.The simulated instances used to assess the performance of the proposed model and CRG method reveal that both CPLEX and the CRG method exhibit comparable and nearly optimal performance for small-scale problems.However,for large-scale instances the proposed TSRO model falls short in terms of computational efficiency.Conversely,the proposed CRG method is capable of significantly reducing computational time and the optimality gap to an acceptable level.展开更多
When designing a solar power plant, it is much more important to avoid the shadow on the PV Panels. As the shadow falls on the PV Panels;it significantly reduces the generation of required power as planned and designe...When designing a solar power plant, it is much more important to avoid the shadow on the PV Panels. As the shadow falls on the PV Panels;it significantly reduces the generation of required power as planned and designed. This research paper and case study will help a lot to avoid shadow, especially when selecting inter-row spacing between the strings of solar power plants.展开更多
The time domain harmonic balance method is an attractive reduced order method of analyzing unsteady flow for turbomachines. However, the method can admit non-physical solutions. Non-physical solutions were encountered...The time domain harmonic balance method is an attractive reduced order method of analyzing unsteady flow for turbomachines. However, the method can admit non-physical solutions. Non-physical solutions were encountered from a three-blade-row compressor configuration in a time domain harmonic balance analysis. This paper aims to investigate the root cause of the non-physical solutions. The investigation involves several strategies, which include increasing the number of harmonics, increasing the number of time instants, including scattered modes,including the rotor-rotor interaction, and the use of a new method-the approximate time domain nonlinear harmonic method. Numerical analyses pertinent to each strategy are presented to reveal the root cause of the non-physical solution. It is found that the nonlinear interaction of unsteady flow components with different fundamental frequencies is the cause of the non-physical solution. The non-physical solution can be eliminated by incorporating extra scattered modes or using the approximate time domain nonlinear harmonic method.展开更多
Using a split plot design, super high-yielding early rice ＆quot;Zhongjiazao 17＆quot;and ＆quot;Ganxin 203＆quot; and super high-yielding late rice ＆quot;Ganxin 688＆quot; and ＆quot;Wufengy-ouT025＆quot; were taken...Using a split plot design, super high-yielding early rice ＆quot;Zhongjiazao 17＆quot;and ＆quot;Ganxin 203＆quot; and super high-yielding late rice ＆quot;Ganxin 688＆quot; and ＆quot;Wufengy-ouT025＆quot; were taken as materials with planting density the same at 312 000 hil s/hm2, to explore the effects of RS/IS （Ratio of row spacing to intrarow row spacing） on yield, top three leaves morphological features and its relationship of them in 2011 and 2012. The results showed that, whether early or late rice, biomass, accumula-tion and apparent utilizing rate of nitrogen were lower in RS/IS5.0 （40.0 cm ＆#215;8.0 cm） treatment, but yield of rice was higher in RS/IS2.0 （25.0 cm ＆#215;12.8 cm） treatment;grain numbers per spike of rice was more in RS/IS2.8 （30.0 cm＆#215;10.7 cm） treatment, and thousand-grain weight of rice was higher in RS/IS1.3 （20.0 cm＆#215;16.0 cm） treat-ment. For 4 varieties of early or late rice aforementioned, basal angle, opening an-gle and leaf area of 2nd leaf from top were larger in RS/IS5.0 treatment, and basal angle and opening angle were smal er in RS/IS2.0 treatment and leaf area smal er in RS/IS1.3 treatment.展开更多
Plausible reasoning is an important approach to reasoning conclusions.In order to cultivate students’habits and abilities to use plausible reasoning,we should give the students a chance to imitate and practice plausi...Plausible reasoning is an important approach to reasoning conclusions.In order to cultivate students’habits and abilities to use plausible reasoning,we should give the students a chance to imitate and practice plausible reasoning in our teaching.For our linear algebra course,most of the definitions and theorems in popular linear algebra textbooks are given directly.Thus,we give a concrete process that rediscovers determinant expansion on row or column theorem through plausible reasoning during our teaching to give the students the chance to learn the reasoning.展开更多
基金supported by the National Natural Science Foundation of China (No. 51206008)
文摘Extensive experimental studies on the heat transfer characteristics of two rows of aligned jet holes impinging on a concave surface in a wing leading edge were conducted, where50000 Rej 90000, 1.74 H/d 27.5, 66° a 90°, and 13.2 r/d 42.03. The finding was that the heat transfer performance at the jet-impingement stagnation point with two rows of aligned jet holes was the same as that with a single row of jet holes or the middle row of three-row configurations when the circumferential angle of the two jet holes was larger than 30°. The attenuation coefficient distribution of the jet impingement heat transfer in the chordwise direction was so complicated that two zones were divided for a better analysis. It indicated that： the attenuation coefficient curve in the jet impingement zone exhibited an approximate upside-down bell shape with double peaks and a single valley; the attenuation coefficient curve in the non-jet impingement zone was like a half-bell shape, which was similar to that with three rows of aligned jet holes; the factors,including Rej, H/d and r/d, affected the attenuation coefficient value at the valley significantly.When r/d was increased from 30.75 to 42.03, the attenuation rates of attenuation coefficient increased only by 1.8%. Consequently, experimental data-based correlation equations of the Nusselt number for the heat transfer at the jet-impingement stagnation point and the distributionof the attenuation coefficient in the chordwise direction were acquired, which play an important role in designing the wing leading edge anti-icing system with two rows of aligned jet holes.
文摘China is one of the world's largest agricultural countries, planting a variety of crops, and maize is one of which has a relatively large planting area and is an important food and commercial crop. With the development of agricultural modernization, the high-yield planting technology of maize has been in continuous research and development, among which many advanced technologies have been applied. Wide-narrow row alternate planting is one of the more representative ones, and its application scope is very wide. Almost all planting areas of maize are adopting it, which has made an important contribution to the improvement of high-yield and quality of maize. In this paper, the application of maize's wide and narrow row alternate planting technology is analyzed in depth.
基金This work was financially supported by the Key-Area Research and Development Program of Guangdong Province(Grant No.2019B020221002)and the National Key Research and Development Program of China(Grant No.2017YFD0701105)The authors also acknowledge the anonymous reviewers for their critical comments and suggestions for improving the manuscript.
文摘Paddy field management is complicated and labor intensive.Correct row detection is important to automatically track rice rows.In this study,a novel method was proposed for accurate rice row recognition in paddy field transplanted by machine before the disappearance of row information.Firstly,Bayesian decision theory based on the minimum error was used to classify the period of collected images into three periods(T1:0-7 d;T2:7-28 d;T3:28-45 d),and resulting in the correct recognition rate was 97.03%.Moreover,secondary clustering of feature points was proposed,which can solve some problems such as row breaking and tilting.Then,the robust regression least squares method(RRLSM)for linear fitting was proposed to fit rice rows to effectively eliminate interference by outliers.Finally,a credibility analysis of connected region markers was proposed to evaluate the accuracy of fitting lines.When the threshold of credibility was set at 40%,the correct recognition rate of fitting lines was 96.32%.The result showed that the method can effectively solve the problems caused by the presence of duckweed,high-density inter-row weeds,broken rows,tilting(±60°),wind and overlap.
基金The authors acknowledge that the research was financially supported by the National Key Research and Development Program of China(Grant No.2017YFD0700902)the University Synergy Innovation Program of Anhui Province(Grant No.GXXT-2020-011).
文摘Crop rows detection in maize fields remains a challenging problem due to variation in illumination and weeds interference under field conditions.This study proposed an algorithm for detecting crop rows based on adaptive multi-region of interest(multi-ROI).First,the image was segmented into crop and soil and divided into several horizontally labeled strips.Feature points were located in the first image strip and initial ROI was determined.Then,the ROI window was shifted upward.For the next image strip,the operations for the previous strip were repeated until multiple ROIs were obtained.Finally,the least square method was carried out to extract navigation lines and detection lines in multi-ROI.The detection accuracy of the method was 95.3%.The average computation time was 240.8 ms.The results suggest that the proposed method has generally favorable performance and can meet the real-time and accuracy requirements for field navigation.
基金Sao Paulo Research Founda-tion(FAPESP grant#2017/12646-3)National Council for Scien-tific and Technological Development(CNPq grant#309330/2018-1)Coordination for the Improvement of Higher Education Personnel(CAPES Finance Code#001)for their financial support.
文摘Sugarcane planting is an important and growing activity in Brazil.Thereupon,several techniques have been developed over the years to maximize crop productivity and profit,amongst them,processing of sugarcane field images.In this sense,this research aims to identify and analyze crop rows and measure their gaps from aerial images of sugarcane fields.For this,a small Remotely Piloted Aircraft captured the images,generating orthomosaics of the areas for analysis.Then,each orthomosaic is classified with the K-Nearest Neighbor algorithm to segment regions of interest.Planting row orientation is estimated using the RGB gradient filter.Morphological operations and computational geometry models are then used to detect and map rows and gaps along the planting row segment.To evaluate the results,crop rows are mapped and compared to manually taken measurements.Our technique obtained an error smaller than 2%when compared to gap length in crop rows from an orthomosaic with the area of 8.05 ha(ha).The proposed approach can map the positioning of the automatically generated row segments appropriately onto manually created segments.Moreover,our method also achieved similar results when confronted with a manual technique for differing growth stages(40 and 80 days after harvest)of the sugarcane crop.The proposed method presents a great potential to be adopted in sugarcane planting monitoring。
基金supported by the National Major Science and Technology Program on New Genetically Modified Organism Variety Breeding,China(Grant No.2016ZX08001-001).
文摘Rice leaf morphology is of great significance in the breeding of an ideal plant type and high photosynthetic efficiency.A forward genetics approach was employed to locate a novel gene,NRL9(NARROW AND ROLLED LEAF 9).NRL9 encodes a 20S proteasome β1 subunit and is involved in regulating leaf morphology and grain size.Compared with the wild type(WT),the nrl9 mutant exhibited a significant decrease in leaf width,and a significant increase in leaf rolling index(LRI),while also displaying increased grain length and decreased grain width.
基金Supported by China Agriculture(Cotton)Research System(CARS-15-46)Intellectual Aid Xinjiang Innovation and Expansion Talent Program of Xinjiang Uygur Autonomous Region(2024500207).
文摘[Objectives]To provide a reference for the promotion of appropriate row spacing configuration modes for cotton planting in the Bortala Mongol Autonomous Prefecture of Xinjiang.[Methods]Xinluzao 63 was employed as the research subject to examine the effects of three different configuration modes:three rows with one film,four rows with one film,and six rows with one film,on the growth and development of cotton,as well as on yield and the amount of residual film in the field.[Results]In comparison to the configuration modes of four rows with one film and six rows with one film,the development process in the row spacing configuration mode of three rows with one film was accelerated by 1-4 d.This configuration mode exhibited variability in several agronomic traits,particularly in plant height,the number of fruiting branches per plant,and the number of leaves per plant,with the observed trend indicating T3>T2>T1.Conversely,the height of the first fruiting branch node displayed an inverse trend.In terms of yield composition,no significant differences were observed in boll weight and yield among various configuration modes.However,T3 exhibited the highest boll weight at 5.68 g and a yield of 462.67 kg/667 m 2.Additionally,significant differences were noted in harvesting density and the number of bolls per plant.T3 demonstrated the lowest harvesting density at 1.11×104 plants/666.7 m 2,the highest number of bolls per plant at 8.63,and the highest boll opening rate at 97.48%.Furthermore,T3 also resulted in the least amount of agricultural film residue during the current season.[Conclusions]Among the three planting configuration modes examined,the low-density planting configuration mode consisting of three rows and one film demonstrated a significant advantage at the individual plant level.This approach yielded results comparable to those of the high density planting configuration mode while also reducing costs.Furthermore,low density planting positively influenced the cotton boll opening rate,leading to a decreased amount of residual film and promoting ecological health within the agricultural land.
基金the National High Technology Research and Development Program of China through grant number 2002AA503010
文摘This paper describes the numerical simulation of three-dimensional viscous flows in fir-cooled turbine blade rows with the effects of coolant ejection. A TVD Navier-Stokes flow solver incorporated with Baldwin-Lomax turbulence model and multi-grid convergence acceleration algorithm are used for the simulation. The influences of coolant ejection on the main flow are accounted by volumetric coolant source terms. Numerical results for a four-stage turbine are presented and discussed.
基金supported by the National Natural Science Foundation of China(Grant No.31772258)the National Key Research and Development Program(Grant No.2019YFD1000102-11)。
文摘Climate change and extreme weather pose significant challenges to the traditional viticulture regions.Emerging high-altitude grape-producing regions with diverse orientations have shown great potential in coping with this challenge.Stable,high-quality wine grape production may be achieved by synchronizing the meso-and microclimate.To clarify the role of high altitude and row orientation in meso-and microclimate and the response of berries to it,we evaluated seven years(2012-2018)of climate data,two years of basic grape(Cabernet Sauvignon,Vitis vinifera L.)quality,and one-year microclimate from veraison to harvest.By comparing two locations(Sidon 2047 m,Sinon 2208 m)in Yunnan Province,China,we found that the average temperature has been stable at approximately 15℃ for seven years,with no extreme weather or,noticeable global warming.The light intensity(LI)in the north-south(NS)was more balanced than the east-west(EW)direction,and the east-west to the south(EW-S)canopy side was almost higher than the other sides.High LI was associated with high photosynthetically active radiation(PAR),ultraviolet(UV),and infrared(IR)light and vice versa.The north-south to the east(NS-E)and east-west to the north(EWN)sides were characterized by lower LI and higher UV and IR light,and higher total anthocyanin content.Most anthocyanin synthesis-related genes,for example,VvF3'H and VvF3'5'H,were highly expressed in NS-E from veraison to maturity.Perhaps UV and IR light induced their expression.This study provides new insights on the role of differently orientated rows in controlling grape quality due to varied light quality.The findings are globally significant,particularly in the context of climate change,and offer fresh insights into berry physiological responses and decision-making for the management of existing vineyards.
文摘Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considered a replacement for the current Indian production system.It is also suitable for mechanical harvesting,which reducing labour costs,increasing input use efficiency,timely harvesting timely,maintaining cotton quality,and offering the potential to increase productivity and profitability.This technology has become widespread in globally cotton growing regions.Water management is critical for the success of high density cotton planting.Due to the problem of freshwater availability,more crops should be produced per drop of water.In the high-density planting system,optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs.Deficit irrigation is a tool to save water without compromising yield.At the same time,it consumes less water than the normal evapotranspiration of crops.This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation.Based on the current research and combined with cotton production reality,this review discusses the application and future development of deficit irrigation,which may provide theoretical guidance for the sustainable advancement of cotton planting systems.
文摘[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under challenging conditions,such as strong light exposure and weed interference.The aims are to develop an effective crop line extraction method by combining YOLOv8-G,Affinity Propagation,and the Least Squares method to enhance detection accuracy and performance in complex field environments.[Methods]The proposed method employs machine vision techniques to address common field challenges.YOLOv8-G,an improved object detection algorithm that combines YOLOv8 and Ghost‐NetV2 for lightweight,high-speed performance,was used to detect the central points of crops.These points were then clustered using the Affinity Propagation algorithm,followed by the application of the Least Squares method to extract the crop lines.Comparative tests were conducted to evaluate multiple backbone networks within the YOLOv8 framework,and ablation studies were performed to validate the enhancements made in YOLOv8-G.[Results and Discussions]The performance of the proposed method was compared with classical object detection and clustering algorithms.The YOLOv8-G algorithm achieved average precision(AP)values of 98.22%,98.15%,and 97.32%for corn detection at 7,14,and 21 days after emergence,respectively.Additionally,the crop line extraction accuracy across all stages was 96.52%.These results demonstrate the model's ability to maintain high detection accuracy despite challenging conditions in the field.[Conclusions]The proposed crop line extraction method effectively addresses field challenges such as lighting and weed interference,enabling rapid and accurate crop identification.This approach supports the automatic navigation of agricultural machinery,offering significant improvements in the precision and efficiency of field operations.
文摘Motivated by a critical issue of airline planning process,this paper addresses a new two-stage scenario-based robust optimization in operational airline planning to cope with uncertainty and possible flight disruptions.Following the route network scheme and generated flight timetables,aircraft maintenance routing and crew scheduling are critical factors in airline planning and operations cost management.This study considers the simultaneous assignment of aircraft fleet and crew to the scheduled flight while satisfying a set of operational constraints,rules,and regulations.Considering multiple locations for airline maintenance and crew bases,we solve the problem of integrated Aircraft Maintenance Routing and Crew Rostering(AMRCR)to achieve the minimum airline cost.One real challenge to the efficiency of the planning results is the possible disruptions in the initial scheduled flights.Due to the fact that disruption scenarios are expressed discretely with a specified probability,and we provide adjustable decisions under disruption to deal with this disruption risk,we provide a Two-Stage Scenario-Based Robust Optimization(TSRO)model.In this model,here-and-now or first-stage variables are the initial resource assignment.Furthermore,to adapt itself to different disruption scenarios,the model considers some adjustable variables,such as the decision to cancel the flight in case of disruption,as wait-and-see or second-stage variables.Considering the complexity of integrated models,and the scenario-based decomposable structure of the TRSO model to solve it with better computational performance,we apply the column and row generation(CRG)method that iteratively considers the disruption scenarios.The numerical results confirm the applicability of the proposed TSRO model in providing the AMRCR problem with an integrated and robust solution with an acceptable level of computational tractability.To evaluate the proposed TSRO model,which solves the AMRCR problem in an integrated and robust manner,five Key Performance Indicators(KPIs)like Number of delayed/canceled flights,Average delay time,and Average profit are taken into account.As key results driven by conducting a case study,we show the proposed TSRO model has substantially improved the solutions at all indicators compared with those of the sequential/non-integrated and nominal/non-robust models.The simulated instances used to assess the performance of the proposed model and CRG method reveal that both CPLEX and the CRG method exhibit comparable and nearly optimal performance for small-scale problems.However,for large-scale instances the proposed TSRO model falls short in terms of computational efficiency.Conversely,the proposed CRG method is capable of significantly reducing computational time and the optimality gap to an acceptable level.
文摘When designing a solar power plant, it is much more important to avoid the shadow on the PV Panels. As the shadow falls on the PV Panels;it significantly reduces the generation of required power as planned and designed. This research paper and case study will help a lot to avoid shadow, especially when selecting inter-row spacing between the strings of solar power plants.
基金National Natural Science Foundation of China(51976172)National Science and Technology Major Project (2017-II-0009-0023)+1 种基金China’s 111 project(B17037)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX2023056)。
文摘The time domain harmonic balance method is an attractive reduced order method of analyzing unsteady flow for turbomachines. However, the method can admit non-physical solutions. Non-physical solutions were encountered from a three-blade-row compressor configuration in a time domain harmonic balance analysis. This paper aims to investigate the root cause of the non-physical solutions. The investigation involves several strategies, which include increasing the number of harmonics, increasing the number of time instants, including scattered modes,including the rotor-rotor interaction, and the use of a new method-the approximate time domain nonlinear harmonic method. Numerical analyses pertinent to each strategy are presented to reveal the root cause of the non-physical solution. It is found that the nonlinear interaction of unsteady flow components with different fundamental frequencies is the cause of the non-physical solution. The non-physical solution can be eliminated by incorporating extra scattered modes or using the approximate time domain nonlinear harmonic method.
基金Supported by National Key Technology Research and Development Program of China(2012BAD15B03)the Youth Innovation Fund of Jiangxi Academy of Agricultural Sciences(2010-CQN004)~~
文摘Using a split plot design, super high-yielding early rice ＆quot;Zhongjiazao 17＆quot;and ＆quot;Ganxin 203＆quot; and super high-yielding late rice ＆quot;Ganxin 688＆quot; and ＆quot;Wufengy-ouT025＆quot; were taken as materials with planting density the same at 312 000 hil s/hm2, to explore the effects of RS/IS （Ratio of row spacing to intrarow row spacing） on yield, top three leaves morphological features and its relationship of them in 2011 and 2012. The results showed that, whether early or late rice, biomass, accumula-tion and apparent utilizing rate of nitrogen were lower in RS/IS5.0 （40.0 cm ＆#215;8.0 cm） treatment, but yield of rice was higher in RS/IS2.0 （25.0 cm ＆#215;12.8 cm） treatment;grain numbers per spike of rice was more in RS/IS2.8 （30.0 cm＆#215;10.7 cm） treatment, and thousand-grain weight of rice was higher in RS/IS1.3 （20.0 cm＆#215;16.0 cm） treat-ment. For 4 varieties of early or late rice aforementioned, basal angle, opening an-gle and leaf area of 2nd leaf from top were larger in RS/IS5.0 treatment, and basal angle and opening angle were smal er in RS/IS2.0 treatment and leaf area smal er in RS/IS1.3 treatment.
文摘Plausible reasoning is an important approach to reasoning conclusions.In order to cultivate students’habits and abilities to use plausible reasoning,we should give the students a chance to imitate and practice plausible reasoning in our teaching.For our linear algebra course,most of the definitions and theorems in popular linear algebra textbooks are given directly.Thus,we give a concrete process that rediscovers determinant expansion on row or column theorem through plausible reasoning during our teaching to give the students the chance to learn the reasoning.
