The underlying mechanism of variety–water–nitrogen–stubble damage interactions on yield formation in ratoon rice with low stubble height under mechanized harvesting

Agronomic measures are the key to promote the sustainable development of ratoon rice by reducing the damage from mechanical crushing to the residual stubble of the main crop, thereby mitigating the impact on axillary bud sprouting and yield formation in ratoon rice. This study used widely recommended conventional rice Jiafuzhan and hybrid rice Yongyou 2640 as the test materials to conduct a four-factor block design field experiment in a greenhouse of the experimental farm of Fujian Agricultural and Forestry University, China from 2018 to 2019.The treatments included fertilization and no fertilization, alternate wetting and drying irrigation and continuous water flooding irrigation, and plots with and without artificial crushing damage on the rice stubble. At the same time, a 13C stable isotope in-situ detection technology was used to fertilize the pot experiment. The results showed significant interactions among varieties, water management, nitrogen application and stubble status.Relative to the long-term water flooding treatment, the treatment with sequential application of nitrogen fertilizer coupled with moderate field drought for root-vigor and tiller promotion before and after harvesting of the main crop, significantly improved the effective tillers from low position nodes. This in turn increased the effective panicles per plant and grains per panicle by reducing the influence of artificial crushing damage on rice stubble and achieving a high yield of the regenerated rice. Furthermore, the partitioning of 13C assimilates to the residual stubble and its axillary buds were significantly improved at the mature stage of the main crop, while the translocation rate to roots and rhizosphere soil was reduced at the later growth stage of ratooning season rice. This was triggered by the metabolism of hormones and polyamines at the stem base regulated by the interaction of water and fertilizer at this time. We therefore suggest that to achieve a high yield of ratoon rice with low stubble height under mechanized harvesting, the timely application of nitrogen fertilizer is fundamental,coupled with moderate field drying for root-vigor preservation and tiller promotion before and after the mechanical harvesting of the main crop.

Mechanical Behavior Based on Aggregates Microstructure of Ultra-high Performance Concrete

We developed ultra-high performance concrete(UHPC)incorporating mullite sand and brown corundum sand(BCS),and the quartz sand UHPC was utilized to prepare for comparison.The properties of compressive strength,elastic modulus,ultrasonic pulse velocity,flexural strength,and toughness were investigated.Scanning electron microscopy and nanoindentation were also conducted to reveal the underlying mechanisms affecting macroscopic performance.Due to the superior interface bonding properties between mullite sand and matrix,the compressive strength and flexural toughness of UHPC have been significantly improved.Mullite sand and BCS aggregates have higher stiffness than quartz sand,contributing to the excellent elastic modulus exhibited by UHPC.The stiffness and volume of aggregates have a more significant impact on the elastic modulus of UHPC than interface performance,and the latter contributes more to the strength of UHPC.This study will provide a reference for developing UHPC with superior elastic modulus for structural engineering.

Dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates

Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate limitations.In this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates.To our knowledge,this is the first reported practical dynamic interactive metasurface holographic system.We spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed sub-pattern.The switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame rate.Our approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational platform.According to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram creation.Our technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems.

Effect of Shrinkage Reducing Agent and Steel Fiber on the Fluidity and Cracking Performance of Ultra-High Performance Concrete

Due to the low water-cement ratio of ultra-high-performance concrete(UHPC),fluidity and shrinkage cracking are key aspects determining the performance and durability of this type of concrete.In this study,the effects of different types of cementitious materials,chemical shrinkage-reducing agents(SRA)and steel fiber(SF)were assessed.Compared with M2-UHPC and M3-UHPC,M1-UHPC was found to have better fluidity and shrinkage cracking performance.Moreover,different SRA incorporation methods,dosage and different SF types and aspect ratios were implemented.The incorporation of SRA and SF led to a decrease in the fluidity of UHPC.SRA internal content of 1%(NSRA-1%),SRA external content of 1%(WSRA-1%),STS-0.22 and STE-0.7 decreased the fluidity of UHPC by 3.3%,8.3%,9.2%and 25%,respectively.However,SRA and SF improved the UHPC shrinkage cracking performance.NSRA-1%and STE-0.7 reduced the shrinkage value of UHPC by 40%and 60%,respectively,and increased the crack resistance by 338%and 175%,respectively.In addition,the addition of SF was observed to make the microstructure of UHPC more compact,and the compressive strength and flexural strength of 28 d were increased by 26.9%and 19.9%,respectively.

Remaining oil distribution characteristics in an oil reservoir with ultra-high water-cut

An accurate mapping and understanding of remaining oil distribution is very important for water control and stabilize oil production of mature oilfields in ultra-high water-cut stage.Currently,the Tuo-21 Fault Block of the Shengtuo Oilfield has entered the stage of ultra-high water cut(97.2%).Poor adaptability of the well pattern,ineffective water injection cycle and low efficiency of engineering measures(such as workover,re-perforation and utilization of high-capacity pumps)are the significant problems in the ultra-high water-cut reservoir.In order to accurately describe the oil and water flow characteristics,relative permeability curves at high water injection multiple(injected pore volume)and a semiquantitative method is applied to perform fine reservoir simulation of the Sand group 3e7 in the Block.An accurate reservoir model is built and history matching is performed.The distribution characteristics of remaining oil in lateral and vertical directions are quantitatively simulated and analyzed.The results show that the numerical simulation considering relative permeability at high injection multiple can reflect truly the remaining oil distribution characteristics after water flooding in an ultrahigh water-cut stage.The distribution of remaining oil saturation can be mapped more accurately and quantitatively by using the‘four-points and five-types’classification method,providing a basis for potential tapping of various remaining oil types of oil reservoirs in late-stage of development with high water-cut.

A universal multifunctional dual cation doping strategy towards stabilized ultra-high nickel cobalt-free lithium layered oxide cathode

Ultra-high nickel cobalt-free lithium layered oxides are promising cathode material for lithium-ion batteries(LIBs)because of their relatively high capacity and low cost.Nevertheless,the high nickel content would induce bulk structure degradation and interfacial environment deterioration,and the absence of Co element reduces the lithium diffusion kinetics,severely limiting the performance liberation of this kind of cathodes.Herein,a multifunctional Ti/Zr dual cation co-doping strategy has been employed to improve the lithium storage performance of LiNi_(0.9)Mn_(0.1)O_(2)(NM91)cathode.On the one hand,the Ti/Zr co-doping weakens the Li^(+)/Ni^(2+)mixing through magnetic interactions due to the inexistence of unpaired electrons for Ti^(4+)and Zr^(4+),increasing the lithium diffusion rate and suppressing the harmful coexistence of H1 and H2 phases.On the other hand,they enhance the lattice oxygen stability because of the strong Ti-O and Zr-O bonds,inhibiting the undesired H3 phase transition and lattice oxygen loss,improving the bulk structure and cathode-electrolyte interface stability.As a result,the Ti/Zr co-doped NM91(NMTZ)exhibits a 91.2%capacity retention rate after 100 cycles,while that of NM91 is only82.9%.Also,the NMTZ displays better rate performance than NM91 with output capacities of 115 and93 mA h g^(-1)at a high current density of 5 C,respectively.Moreover,the designed NMTZ could enable the full battery to deliver an energy density up to 263 W h kg^(-1),making the ultra-high nickel cobaltfree lithium layered oxide cathode closer to practical applications.

Amine-functionalized metal organic framework@graphene oxide as filler in PAEK-containing carboxyl group membrane for ultrafiltration with ultra-high permeability and strong fouling resistance

Achieving high fouling resistance and permeability using membrane separation technology in water treatment processes remains a challenge.In this work,a novel mixed-matrix membrane(MMM)(poly(arylene ether ketone)[PAEK]-containing carboxyl groups[PAEK-COOH]/UiO-66-NH_(2)@graphene oxide[GO])with superb fouling resistance and high permeability was prepared by the nonsolvent-induced phase separation method,by in-situ growth of UiO-66-NH_(2) on the GO layer,and by preparing hydrophilic PAEK-COOH.On the basis of the structure and performance analysis of the MMM,the maximum water flux reached 591.25 L·m^(-2)·h^(-1) for PAEK-COOH/UiO-66-NH_(2)@GO,whereas the retention rate for bovine serum albumin increased from 85.40%to 94.87%.As the loading gradually increased,the hydrophilicity of the MMMs increased,significantly enhancing their fouling resistance.The strongest anti-fouling ability observed was 94.74%,which was 2.02 times greater than that of the pure membrane.At the same time,the MMMs contained internal amide and hydrogen bonds during the preparation process,forming a cross-linked structure,which further enhanced the mechanical strength and chemical stability.In summary,the MMMs with high retention rate,strong permeability,and anti-fouling ability were successfully prepared.

The Effect of Long-term Grazing Sheep in the Cotton Stubble on the Blood Biochemicals and Free Gossypol Residues

The objective of this study was to investigate the effect of long-term grazing sheep in cotton stubble on variation of biochemistry components and free gossypol residual in the blood. The survey found that 15% ewe of grazing group suffered miscarriage or premature birth,compared with the captive group ewes without this phenomenon. Blood test result shows that the free gossypol concentration in serum of grazing group was significantly higher than in indoor captive feeding group( P < 0. 01). In order to ensure the health of sheep grazing on cotton stubble and improve breeding rate,there is a need to do further reasonable research of grazing and feeding methods.

Weed growth, herbicide efficacy, and rice productivity in dry seeded paddy field under different wheat stubble management methods

To ascertain the influence of wheat stubble management options and chemical weed control methods on weed growth and productivity of dry direct-seeded fine rice, a two years' field study was undertaken at the Agronomic Research Farm, University of Agriculture, Faisalabad, Pakistan in 2013 and 2014. Different wheat stubble management methods, viz., incorporation, burning and retention were executed during seed-bed preparation. While, herbicide treatments comprised of a weed check, weed free, pendimethalin followed by tank mixture of fenoxaprop p-ethyl+ethoxysulfuron ethyl, and bispyribac sodium followed by tank mixture of fenoxaprop p-ethyl+ethoxysulfuron ethyl. Results revealed that weed control efficacy of both herbicide treatments ranged from 84 to 94%. Herbicide treatments significantly reduced weed density(88–90%) and dry weight(86–88%), while improved the rice growth attributes compared with weed check. Application of bispyribac sodium followed by tank mixture of fenoxaprop p-ethyl+ethoxysulfuron ethyl in stubble retention recorded 226 and 273% increase in kernel yield over weedy check in 2013 and 2014, respectively. In stubble incorporation, pendimethalin followed by tank mixture of fenoxaprop p-ethyl+ethoxysulfuron ethyl was more effective in increasing(256–293%) rice yields over weedy check. Among different treatment combinations, the maximum net benefits(1 397.49^(–1) 472.22 USD ha^(–1)), net returns(636–700 USD ha^(–1)), benefit cost ratio(1.77^(–1).83) and marginal rate of return(2 187–2 330%) were recorded with the application of bispyribac sodium followed by fenoxaprop p-ethyl+ethoxysulfuron ethyl in stubble retention. In crux, application of bispyribac sodium followed by tank mixture of fenoxaprop p-ethyl+ethoxysulfuron ethyl in stubble retention is efficient approach to control weeds, and get maximum rice productivity and net economic returns under dry seeded system.

Suppression of weeds and weed seeds in the soil by stubbles and no-tillage in an arid maize-winter wheat-common vetch rotation on the Loess Plateau of China

Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, high abundances of weeds in reduced tillage systems cause significant yield losses. In this study, we explored the effects of no-tillage and stubble retention on the number and density of weeds and weed seeds in a 12-year maize-winter wheat-common vetch rotation on the Loess Plateau. Four treatments including conventional tillage, no-tillage, conventional tillage＋stubble retention and no-tillage＋stubble retention were designed and applied. We found that no-tillage increased the number of weed species and weed density in most of the crops, while stubble retention decreased weed density in maize and tended to suppress weeds in both no-tillage treatments（no-tillage and no-tillage＋stubble retention）. No-tillage led to an increase in the number of weed species in the weed seedbank and tended to increase seed density during the spring growth of winter wheat, but it decreased seed density during post-vetch fallow. Stubble retention tended to reduce seed density during the spring growth of winter wheat and post-vetch fallow. We concluded that no-tillage can promote weeds in the experimental crop rotation, while stubble retention suppresses weeds in untilled fields. The combined effects of stubble retention and no-tillage on weed suppression varied among the three crops. Based on these results, we recommend stubble retention in untilled legume-crop rotations on the Loess Plateau to improve the control of weeds.

Effects of Crop Stubble on Physicochemical Properties of Continuous Cropping Soil and Cucumber Yield and Quality

By a pot experiment, two kinds of crop stubble (wheat, soybean) were added into continuous cropping soil of cucumber according to different quantity (0.5%, 1% and 2%), the effects of different kinds of stubble and quantity on the continuous cropping soil and growth of cucumber were investigated. The results showed that two kinds of crop stubble significantly decreased soil bulk density, and increased total porosity of soil. Each of all treatments significantly decreased the accumulation of salinity in soil within the entire growth period of cucumber. 2% wheat stubble treatment had the biggest drop in soil EC in the later period of cucumber growth. Soybean stubble treatment had the lesser effect on soil EC. Wheat and soybean stubble promoted the growth of cucumber, increased the yield of cucumber, and improved the quality of cucumber. 2% of wheat stubble treatment had a biggest increase in cucumber yield, which increased the yield by 34.23% compared with the control.

Effects of Mechanical Harvesting on Sugarcane Stubble Quality and Growth of Ratoon

The experiment was conducted with the traditional manual harvesting and mechanical harvesting of sugarcane,to compare the effects of different harvesting method on the sugarcane stubble quality and the growth of ratoon.The experimental results are as follows.(i) The stubble height and breaking stubble rate of mechanical harvesting was significantly higher than manual harvesting,the stubble height of lodging species and difficult defoliation species increased in mechanical harvesting condition.Varieties with higher levels of fiber had lower rate of broken stubble.(ii) The effects of mechanical harvesting on germination of next year ratoon were quite different due to different varieties,indicating that the better perennial species have less impact than the poor perennial species.(iii) Compared with manual harvesting,mechanical harvesting had slightly higher plant height and single-stem weight and less effective stems number,the difference of cane yield was not significant,but sucrose content increased 0.53%.(iv) Mechanical harvesting combining with leaves crushing could reduce the impact on the germination of ratoon,improve the single-stem weight and increase the effective number of stems.

Effects of Mowing Stubbles and Mowing Stages on Nutrient Contents of Forage Mulberry

[Objective]The paper was to study the effects of mowing on nutrients of forage mulberry.[Method]With forage mulberry as the research object,the effects of mowing stubbles and mowing stages on nutrient content of forage mulberry were studied.[Result]With the increase of mowing frequency,the crude protein and crude ash content of forage mulberry decreased,but the crude fiber content increased,and the quality of forage mulberry decreased correspondingly.The crude protein content decreased most obviously from 25.78%in the first stubble to 21.63%in the third stubble.In the first and third stubble,the nutrients at 28±1 d after the last mowing were higher than that at 38±1 d after the last mowing.That is,with the growth of forage mulberry,the accumulated nutrients were also used for their own growth.[Conclusion]From the perspective of nutrient content,the forage mulberry mowed earlier has higher nutritional value and better palatability.

Response of Stubble Shaving Times on Ratoon Yield of Different Sugarcane Genotypes

Ratooning is common practice done in sugarcane with purpose of reducing the total cost of cultivation and early cane maturity.More than 35%of sugarcane productivity is lost due to improper attention of the farmers towards ratoons.Majority of farmers reported that the ratoonability wasn’t good when harvested in December-January.This experiment was carried out to find the appropriate ratoon shaving time with response to different varieties in sugarcane ratoon crop in the year 2018/19 at national sugarcane research project,Jitpur,Bara.The experiment was conducted in split plot design with four levels of cane genotypes as Co–0238,CoLk–94184,Co–0233 and CoS–07250 as the main plot factor while four harvesting dates as sub plot factor with three replications.Observations of a number of millable canes,single cane weight,plant height and single cane diameter were recorded,tabulated and analyzed in R-studio.Ratoon stubble shaving in the month of November had the highest number of millable canes(88079/ha)which wasn’t significantly different from the stubble shaving in the month of December,January.Likewise,highest cane yield(60.04 mt/ha),single cane weight(0.757 kg),cane diameter(2.11 cm),plant height(1.82 m)were found in early stubble shaving dates.Cane Yield and various yield parameter shows better performance in early ratoon shaving periods i.e.from November to January than late ratoon shaving dates.

Utilization of Crop Stubble as Alternate Source of Electricity Generation

The Indian states including Punjab,Haryana,Bihar,Uttar Pradesh,Madhya Pradesh,and Himachal Pradesh follow combine harvesting method followed by burning of crop stubble to prepare the fields for next crop.Crop stubble burning is the reason of annual increment in pollution concentrations which lead to massive winter pollution in the region.However,the state governments have taken several initiatives for proper management of crop stubble through various departments and institutions but still air pollution level is increasing.Instead of burning the crop residue,it can be used in other ways,which are beneficial to humanity.In the direction of rising issues due to burning of the crop stubble,efforts have been carried out to explore the options to utilize the crop stubble rather than burning of it.Present experimental study is an attempt to outline alternative use of crop stubble like utilization of rice straw for electricity generation through microbial fuel cell.In 10 days experimental set up,the MFC produced the maximum voltage of 0.002 V corresponding to the maximum current of 2.5 mA which results in power output of 0.05 mW.The experiments'results of the study accentuate the significance of biomass by utilizing the rice paddy straw for generating the electricity by means of microbial fuel cells.The electricity generated through crop stubble can be used as a sustainable source of energy in the remote areas.It is also focused on suggesting policies to the government so that air pollution can be minimized in affected areas.

Comprehensive evaluation of chemical breakers for multistage network ultra-high strength gel

Polymer gels have been accepted as a useful tool to address many sealing operations such as drilling and completion,well stimulation,wellbore integrity,water and gas shutoff,etc.Previously,we developed an ultra-high strength gel(USGel)for medium to ultra-low temperature reservoirs.However,the removal of USGel is a difficult problem for most temporary plugging operations.This paper first provides new insights into the mechanism of USGel,where multistage network structure and physical entanglement are the main reasons for USGel possessing ultra-high strength.Then the effects of acid breakers,encapsulated breakers,and oxidation breakers(including H_(2)O_(2),Na_(2)S_(2)O_(8),Ca(ClO)_(2),H_(2)O_(2)+NaOH,Na_(2)S_(2)O_(8)+NaOH,and Ca(ClO)_(2)+NaOH)were evaluated.The effects of component concentration and temperature on the breaking solution were studied,and the corrosion performance,physical simulation and formation damage tests of the breaking solution were carried out.The final formulation of 2%-4%NaOH+4.5%-6%H_(2)O_(2) breaking solution was determined,which can make USGel completely turn into water at 35e105C.The combinations of“acid t breaking solution”,“acid+encapsulated breaker”and“encapsulated breaker+breaking solution”were evaluated for breaking effect.The acid gradually reduced the volume of USGel,which increased the contact area between breaking solution and USGel,and the effect of“4%acid+breaking solution”was 23 times higher than that of breaking solution alone at 35C.However,the acid significantly reduced the strength of USGel.This paper provides new insights into the breaking of high-strength gels with complex network structures.

Combination of a reaction cell and an ultra-high vacuum system for the in situ preparation and characterization of a model catalyst

An in-depth understanding of the structure-activity relationship between the surface structure,chemical composition,adsorption and desorption of molecules,and their reaction activity and selectivity is necessary for the rational design of high-performance catalysts.Herein,we present a method for studying catalytic mechanisms using a combination of in situ reaction cells and surface science techniques.The proposed system consists of four parts:preparation chamber,temperatureprogrammed desorption(TPD)chamber,quick load-lock chamber,and in situ reaction cell.The preparation chamber was equipped with setups based on the surface science techniques used for standard sample preparation and characterization,including an Ar+sputter gun,Auger electron spectrometer,and a low-energy electron diffractometer.After a well-defined model catalyst was prepared,the sample was transferred to a TPD chamber to investigate the adsorption and desorption of the probe molecule,or to the reaction cell,to measure the catalytic activity.A thermal desorption experiment for methanol on a clean Cu(111)surface was conducted to demonstrate the functionality of the preparation and TPD chambers.Moreover,the repeatability of the in situ reaction cell experiment was verified by CO_(2) hydrogenation on the Ni(110)surface.At a reaction pressure of 800 Torr at 673 K,turnover frequencies for the methanation reaction and reverse water-gas shift reaction were 0.15 and 7.55 Ni atom^(-1) s^(-1),respectively.

Influence Mechanism of Curing Regimes on Interfacial Transition Zone of Lightweight Ultra-High Performance Concrete

This study aims to clarify the effects of curing regimes and lightweight aggregate(LWA)on the morphology, width and mechanical properties of the interfacial transition zone(ITZ) of ultra-high performance concrete(UHPC), and provide reference for the selection of lightweight ultra-high performance concrete(L-UHPC) curing regimes and the pre-wetting degree LWA. The results show that, under the three curing regimes(standard curing, steam curing and autoclaved curing), LWA is tightly bound to the matrix without obvious boundaries. ITZ width increases with the water absorption of LWA and decreases with increasing curing temperature. The ITZ microhardness is the highest when water absorption is 3%, and the microhardness value is more stable with the distance from LWA. Steam and autoclaved curing increase ITZ microhardness compared to standard curing. As LWA pre-wetting and curing temperatures increase, the degree of hydration at the ITZ increases, generating high-density CSH(HD CSH) and ultra-high-density CSH(UHD CSH), and reducing unhydrated particles in ITZ. ITZ micro-mechanical properties are optimized due to hydration products being denser.

Ultra-high Temperature Ceramic Coatings:A Review on Preparation Technology and Development Prospect

Ultra-high temperature ceramic coatings have ultra-high melting points,excellent mechanical properties and high temperature ablation resistance.These unique performance combinations turn it into a promising material for use in extreme environment structures in rockets and hypersonic vehicles,particularly nozzles,leading edges and engine components.In this paper,various preparation methods of ultra-high temperature ceramic coatings were reviewed,including plasma spraying,chemical vapor deposition,pack cementation,slurry sintering,hot pressing and their research progress.Meanwhile,some new preparation methods of high temperature coatings,such as ion beam deposition,ultrasonic spraying,metal organic frame work coating,and magnetron sputtering,were introduced.The development trend of ultra-high temperature coatings was prospected as well.

Evaluation of Uncertainty in Determination of Ethyl Maltol in Vegetable Oil by Ultra-high Performance Liquid Chromatograph-Mass Spectrometer(UPLC-MS)

[Objectives]This study was conducted to establish an uncertainty evaluation method for the determination of ethyl maltol by ultra-high performance liquid chromatograph-mass spectrometer(UPLC-MS).[Methods]A mathematical model of uncertainty was established by analyzing the method for determining ethyl maltol using UPLC-MS.The sources of uncertainty were analyzed,and the components of uncertainty were calculated to evaluate the expanded uncertainty of the method.[Results]When the content of ethyl maltol in edible vegetable oil was 1657μg/kg,the expanded uncertainty was 22.4μg/kg(K=2,P=95%).[Conclusions]The uncertainty in this evaluation model mainly came from standard solution preparation,sample weighing,dilution of sample to constant volume,standard curve fitting,and repeated measurement.