One of the solutions to the global warming risk and other climate issues is to concentrate on research and development of utilizing biomass as a fossil fuel alternative.The current estimate of cotton residue waste in ...One of the solutions to the global warming risk and other climate issues is to concentrate on research and development of utilizing biomass as a fossil fuel alternative.The current estimate of cotton residue waste in the world is about 50 million tons.This massive volume of biomass waste should be turned into clean energy to avert burning the stalks in open fields after cotton harvesting.Therefore,harmful emissions such as CO_(2) will be reduced.This study aims to investigate the published literature to comprehend the bioenergy production from the thermal treatment of cotton stalks,including combustion,pyrolysis,carbonization,torrefaction,liquefaction,and gasification.Furthermore,the future outlook,utilization,and prospective challenges of agricultural biomass for biofuel production are discussed.According to the literature,biochar and bio-oil derived from cotton stalks have high heating values of about 27.5 and 37.2 MJ·kg~(–1),respectively.These values are double those of cotton stalk raw materials,which make it a good candidate for bioenergy production.This article offers valuable insight into cotton stalk utilization via thermochemical treatment and provides a solid reference for researchers,policymakers,and other stakeholders in this field.展开更多
[Objective] The study aimed at reducing the economic cost in feeding Tenebrio molitor and improving the utilization ratio of corn stalks.[Method] The effects of different proportions of corn stalks on the weigh of Ten...[Objective] The study aimed at reducing the economic cost in feeding Tenebrio molitor and improving the utilization ratio of corn stalks.[Method] The effects of different proportions of corn stalks on the weigh of Tenebrio molitor and the contents of crude protein,crude fat,Ca,P,dry matter and crude ash in the half-dry matter of Tenebrio molitor had been studied in the laboratory.[Result] Compared with the recipes of all wheat bran and pure fine fodder,feeding Tenebrio molitor by applying 30%-60% of corn stalks could significantly improve the content of crude protein in the half-dry materials of Tenebrio molitor,but it was detrimental to the improvement in weight of Tenebrio molitor and the accumulation of crude fat.To be specific,the recipe V（50% of corn stalks ＋ 50% of fine fodder） was beneficial to the accumulation of dry matter and crude ash.The recipe VII（70% of corn stalks ＋ 30% of fine fodder） and the recipe VIII（70% of corn stalks treated with Guangda feed leaven ＋ 30% of fine fodder） were beneficial to the accumulation of crude protein,Ca and P.There were differences among the influences of corn stalks in different treatments on the crude protein and other nutrition indicators of Tenebrio molitor.[Conclusion] Appropriately applying corn stalks can improve the accumulation of the crude protein,crude ash,dry matter,Ca and P of Tenebrio molitor but was detrimental to the growth and development of Tenebrio molitor and the accumulation of crude fat.展开更多
[Objective] This study aimed to study the adsorption performance of activated carbon prepared from corn stalks. [Methed] With granular activated carbon prepared from corn stalks as research object, adsorption performa...[Objective] This study aimed to study the adsorption performance of activated carbon prepared from corn stalks. [Methed] With granular activated carbon prepared from corn stalks as research object, adsorption performance simulation test equipment was set up to investigate the adsorption performance of the prepared activated carbon for methanol by static weight method. In addition, the effects of adsorption bed structure, activated carbon particle size in adsorption bed, addition amount of graphite powder in activated carbon and modified activated carbon on systematic adsorption performance were studied. [Result] Under conditions of same activated carbon and same adsorption temperature, the adsorption performance of new adsorption bed A （installed with finned diaphragm adsorbate tubes） was signifi- cantly better than that of unmodified adsorption bed B. Compared with adsorption bed B, adsorption bed A took 5 min shorter to reach the adsorption amount of 0.22 g/g. Under the same adsorption temperature, the adsorption performance of bed loaded with different-particle size activated carbon was significantly better than that loaded with same-particle size activated carbon. The bed loaded with different-particle size activated carbon took 16 min shorter to reach the adsorption capacity of 0.22 g/g compared with the bed loaded with same-particle size activated carbon. Adding proper amount of graphite powder in activated carbon could enhance the thermal conductivity and strengthen the adsorption properties. The optimum addition amount of graphite powder was 20% of the total amount of activated carbon. Com- pared with that of the control, the adsorption performance of activated carbon soaked by weak acidic solution was significantly improved. It took 3 min shorter to reach 87.1% of the equilibrium adsorption amount. [Conclusion] This study will provide reference for optimizing structural design of adsorption bed and adsorption refrigeration system.展开更多
[Objective] To study the correlation between the biomechanical properties of rape stalks and rape stem lodging. [Method] Through axial compression tests to the stalks of 4 different rape varieties, the change rules of...[Objective] To study the correlation between the biomechanical properties of rape stalks and rape stem lodging. [Method] Through axial compression tests to the stalks of 4 different rape varieties, the change rules of maximum stem bearing ca- pacity, maximum compressive strength, elastic modulus and moment of inertia along plant height were analyzed, as well as the effect of different varieties and water contents on the biomechanical property indices of rape stalks. [Result] The maximum loads of rape stalks presented liner decrease trend along with the increase of stem height, and all reached the maximums below the height of 50 cm. The maximum stem compressive strength and elastic modulus of the 4 varieties were increased with ascending height, but in a slow rate with small change, thus the modulus of e- lasticity could be considered as unchanged. The maximum bearing capacity, maxi- mum compressive strength and elastic modulus of dry rape stalks were higher than wet stalks, indicating that the water contents of rape stalks had significant effect on their mechanical properties. According to the actual lodging situations in filed, stalks of variety No. 1 owned the worst biomechanical properties and lodging degree, while the biomechanical properties of No. 6 and F5 were better than No. 1 and No. 9, and they also had stronger lodging-resistance. [Conclusion] The study provides parameters and bases for the design of mechanized production and mechanical deep processing of crops, and can better reveal the physical natures of organisms. The methods used in this study can also be used to screen excellent crop stalks.展开更多
We undertook a pyrolysis research on garlic stalks to solve its difficulty in use. We found that the inorganic salts in biomass played an important role in catalytic pyrolysis. Moreover, we studied the pyrolysis behav...We undertook a pyrolysis research on garlic stalks to solve its difficulty in use. We found that the inorganic salts in biomass played an important role in catalytic pyrolysis. Moreover, we studied the pyrolysis behavior under catalyst and catalyst-free conditions. The results showed that the weightlessness rate of garlic stalks was the highest at 550 ℃ under catalyst-free condition. The oil production rate increased with the increase of temperature and reached the peak at 550 ℃. Subsequently, as the temperature increased, the secondary cracking was intensified and oil production rate was decreased. The oil production rate increased significantly （almost 15%） under catalysis of KOH. However, the oil production rate was the highest at 500-600℃. What＇s more, we found that KOH played a major role in promoting decomposition of surface skin cells and subcutaneous fibrous layer of garlic stalks.展开更多
Pretreatment of lespedeza stalks by steam explosion has been studied. The results indicate that steam-exploded pretreatment has strong effects on physical features, morphology, crystallinity, and composition of lesped...Pretreatment of lespedeza stalks by steam explosion has been studied. The results indicate that steam-exploded pretreatment has strong effects on physical features, morphology, crystallinity, and composition of lespedeza stalks as shown by scanning electron microscopy （SEM）, infrared （IR）, and X-ray diffraction spectrometry methods. After steam explosion, the cellulose and lignin contents of lespedeza stalks varied only slightly, but the hemicellulose content had decreased from 29.34% to 7.48%. The cellulose obtained by steam-exploded pretreatment had a higher degree of crystallinity than that of the raw material. At the explosion condition of 2.25 MPa and 4 min, lignocellulose is easier to hydrolyze by enzyme than the original lignocellulose. The concentration of reduced sugar in the hydrolyzate liquid increased from 71.77 to 162.84 g·L^-1.展开更多
It is very difficult to directly spin the lignocellulose without pretreatment.Ionic liquids(ILs)are promising solvent to dissolve lignocellulose to prepare cellulose fiber.However,the degree of cellulose polymerizatio...It is very difficult to directly spin the lignocellulose without pretreatment.Ionic liquids(ILs)are promising solvent to dissolve lignocellulose to prepare cellulose fiber.However,the degree of cellulose polymerization(DP)is reduced when lignocellulose is dissolved in ILs,and the lignin removal rate is low.The elongation at break and tensile strength of the fibers obtained by spinning the lignocellulose dissolved in ILs are poor.In this paper,preparing cellulose fiber directly from lignocellulose based on dissolving corn stalk via[C4mim]Cl-L-arginine binary system is achieved.It shows that the removal rate of lignin can reach 92.35%and the purity of cellulose can reach 85.32%after corn stalk was dissolved at 150℃C for 11.5 h when the mass fraction of arginine is 2.5%.The elongation at break of fiber reached 10.12%and the tensile strength reached 420 MPa.It is mainly due to the fact that L-arginine not only inhibits the degradation of cellulose but also promotes the delignination.Without any pulping or pretreatment,preparing cellulose fibers via direct dissolution and extrusion may provide a simple and effective way to prepare many novel cellulose materials.展开更多
Sweet potato(Ipomoea batatas Lam.)leaf stalks were cut into 20 cm length,and stored at 20,6,and 2℃.The respiration rate,ethylene production,ascorbic acid,free amino acid,total chlorophyll content,freshness,and shelf ...Sweet potato(Ipomoea batatas Lam.)leaf stalks were cut into 20 cm length,and stored at 20,6,and 2℃.The respiration rate,ethylene production,ascorbic acid,free amino acid,total chlorophyll content,freshness,and shelf life were determined during storage to investigate the effect of storage temperatures on the quality and physiological responses in sweet potato leaf stalks.Wound responses were observed as high respiration rate and ethylene production immediately after cutting.Sweet potato leaf stalks were found to be sensitive to chilling injury manifested as browning and water-soaking on the surface at 2℃.In contrast,sweet potato leaf stalks were susceptible to senescence,exhibited by etiolating and yellowing,at 20℃.Loss in weight and chlorophyll was minimized under low temperatures.High temperatures also caused the accumulation of amino acids with a significant loss of ascorbic acid and chlorophyll.Sweet potato leaf stalks had a storage life of 16 days at 6℃,8 days at 2℃,and 6 days at 20℃,respectively.展开更多
Lespedeza stalks were subjected to steam pretreatment at 210℃ for some steaming time before simultaneous saccharification and fermentation （SSF）. Cellulose-derived glucose was extensively utilized by yeast during S...Lespedeza stalks were subjected to steam pretreatment at 210℃ for some steaming time before simultaneous saccharification and fermentation （SSF）. Cellulose-derived glucose was extensively utilized by yeast during SSE The ethanol yields after steam pretreatment of the lespedeza stalks at 210℃ were 59.3%, 72.8% and 62.2% of the theoretically expected values when the steaming times were 2, 4 and 6 min, respectively. The highest yield from α-cellulose was 92.7% of the theoretical value. Steam explosion pretreatment of lespedeza stalks increased ethanol yields by a factor of 4.4, from 16.4% （untreated） to 72.8% （steam explosion pretreated）.展开更多
In order to reduce the economic costs for breeding Tenebrio molitor L. and increase the utilization rate of corn stalk, with corn, wheat bran and corn stalk as the raw materials, 13 different compound feed were design...In order to reduce the economic costs for breeding Tenebrio molitor L. and increase the utilization rate of corn stalk, with corn, wheat bran and corn stalk as the raw materials, 13 different compound feed were designed by Minitab （R） 15.1.0.0. The design was then divided into two groups based on addition or without addition of vegetable leaves to study the effects of compound feed and vegetable leaves on growth and de- velopment of T. molitor. The results showed that body weight, duration, crude protein content and pupation rate of larvae and emergence rate of adults were significantly affected by compound feed and vegetable leaves （ P 〈 0.05）. The larvae bred with feed 5 had the largest body weight, with the shortest duration; the larvae bred with feed 3 had the highest pupation rate; the larvae bred with feed 7 had the highest crude protein content; the adult bred with feed 9 had the largest emergence rate. Overall breeding effect of feed 7 ＋ vegetable leaves was better than any other groups, with ideal indicators, higher utilization rate and lower breeding cost. Its formula was w （wheat bran） = 33.33%, w （corn） = 33.33%, w （corn stalks） = 33.33%. Therefore, the growth of T. molitorwas significantly affected by feed types, and feed 7 ＋ vegetable leaves could be promoted in the production.展开更多
Maize stalk lignin and cellulose contents are linked to lodging resistance,disease resistance,feed quality and ethanol conversion efficiency.After the six-leaf stage of maize(V6),these constituents are biosynthesized ...Maize stalk lignin and cellulose contents are linked to lodging resistance,disease resistance,feed quality and ethanol conversion efficiency.After the six-leaf stage of maize(V6),these constituents are biosynthesized and accumulated under the control of related enzymes and genes.However,the key enzymes,critical MYB transcription factors,and their dynamic alterations pattern under natural field circumstances are still unknown.Hence,we selected five cultivars with significant differences in lignocellulose content and lodging resistance as testing materials,performed field experiments for two years,and investigated the dynamics of lignin and cellulose content,related enzyme concentrations,and gene expression levels in the 3^(rd) and 5^(th) internodes above the ground after V6.The results showed that lignin and cellulose content increased after V6,stabilizing during the silking stage.This study identified COMT(caffeic acid 3-Omethyltransferase),TAL(tyrosine ammonia-lyase)and PAL(phenylalanine ammonia-lyase)as the key enzymes of lignin biosynthesis,while ZmCOMT,ZmCesA10 and ZmCesA8 were identified as essential genes.ZmMYB8,ZmMYB31 and ZmMYB39 were involved in regulating the expression of genes related to lignin synthesis,with ZmMYB31 potentially acting as a key negative regulator,while ZmMYB39 and ZmMYB8 acting as positive regulators.The study also found that around 14 d after V6 was a critical stage for regulating lignocellulose synthesis in the 3^(rd) to 5^(th) basal internode.This provides a theoretical foundation for developing regulatory techniques and breeding new cultivars to enhance lodging and disease resistance as well as the utility of maize stalks.展开更多
Cellulose biomass is being investigated as a potential substrate for bioethanol production. Cassava stalks were successfully converted to ethanol by fermentation using Saccharomyces cerevisiae TISTR5048, S. cerevisiae...Cellulose biomass is being investigated as a potential substrate for bioethanol production. Cassava stalks were successfully converted to ethanol by fermentation using Saccharomyces cerevisiae TISTR5048, S. cerevisiae KM1195, S. cerevisiae KM7253 and co-culture of S. cerevisiae TISTR5048 and Candida tropicalis TISTR5045. The objective of this study was to assess the ethanol production from cassava stalks by dilute-acid pretreatment and enzymatic hydrolysis that were convertible into ethanol by mono-culture and co-culture of yeast strain. Cassava stalks 1.5% （w/v） in 0.1 M sulfuric acid was pretreated for 30 min at 135 ℃ under the pressure of 15 lb/inch2. The pretreated cassava stalk suspensions were neutralized to pH 5.5 for saccharification process. The enzyme solution （a-amylase, amyloglucosidase, cellulase, xylanase and pectinase solubilized in buffer pH 5.0） was used for hydrolysis ofpretreated cassava stalk at 50 ℃ for 24 h. The hydrolyaste was supplemented with additional nutrients. The culture was incubated at 30 ℃. The pretreatment of the stalk with dilute-acid resulted sugar yield of 0.57 g/g dry matter from enzymatic hydrolysis, which was higher than dilute-alkaline-pretreated and distilled water-pretreated stalk. The sugar hydrolysate was bioconverted to ethanol with separate hydrolysis and fermentation （SHF） and simultaneous saccharification and fermentation （SSF）. The highest ethanol yields of 98.43% and 95.29% were obtained in SHF and SSF, respectively by S. cerevisiae KM1195. The fermentation time of SSF process was 24-32 h shorter than that of the SHF （= 56 h）, but not significantly leading to difference in ethanol production （5.42 g/L-6.22 g/L for SSF; 5.9 g/L-6.23 g/L for SHF）.展开更多
This study explores a novel method for processing cotton stalks—an abundant agricultural byproduct—into long strips that serve as sustainable raw material for engineered bio-based panels.To evaluate the effect of ra...This study explores a novel method for processing cotton stalks—an abundant agricultural byproduct—into long strips that serve as sustainable raw material for engineered bio-based panels.To evaluate the effect of raw material morphology on panel’s performance,two types of cotton stalk-based panels were developed:one using long strips,maintaining fiber continuity,and the other using ground particles,representing conventional processing.A wood strand-based panel made from commercial southern yellow pine strands served as the control.All panels were bonded using phenol-formaldehyde resin and hot-pressed to a target thickness of 12.7 mm and density of 640 kg/m^(3).Their mechanical and physical properties were evaluated through internal bond,bending,thickness swelling,and water absorption tests.Both cotton stalk-based panels showed improved bonding performance compared to the control.The internal bond of the strip-based panel was nearly four times higher than that of the control,while the particlebased panel exceeded it by a factor of two.The strip-based panel showed approximately 15% lower bending stiffness than the wood strand-based panel,yet it surpassed it in load-carrying capacity by 5%.In contrast,the particleboard showed significantly lower bending performance than the strip-based and control panels,despite particle processing being a more conventional method.Both cotton stalk-based panels exhibited higher water absorption and thickness swelling than the wood strand panel.Overall,cotton stalk-based panels—particularly those using strip processing—show promisingmechanical properties,suggesting potential applications in sheathing,furniture,and interior paneling.However,improvements in dimensional stability are needed for broader use.展开更多
In Xinjiang,in the process of whole stalk harvesting of cotton stalks,there is a problem that the cotton stalks are easily pulled off,and there is an urgent need to develop flexible stalk-pulling machines.Through lite...In Xinjiang,in the process of whole stalk harvesting of cotton stalks,there is a problem that the cotton stalks are easily pulled off,and there is an urgent need to develop flexible stalk-pulling machines.Through literature,patent summary,and field research,it is found that domestic researchers have designed many kinds of machines for the problem of easy breaking of cotton stalks,but there is no flexible cotton stalk-pulling machine for the time being.In this study,two flexible cotton stalk-pulling machines were intended to address the problem of easy breakage of cotton stalks.On the basis of the first-generation machine,the design of the second-generation machine was improved.In order to further improve the operational performance of the flexible cotton stalks pulling tools,the operational mechanism of the core working parts of the tools was analyzed and a comparative test was done in a large field.Analysis and the comparative tests proved that improving the clamping working stroke s of the stalk-pulling components can effectively reduce the cotton stalks leakage rate.By using a flexible clamping process,a part of the deformation of cotton stalks can be transferred to the flexible material.To a certain extent,the deformation length L of the contact surface between the cotton stalk and the stalk pulling part is reduced,and the deformation displacementΔy is correspondingly lower.The toughness of the cotton stalk is not significantly decreased and the cotton stalk does not break easily.The improved second-generation machine has a 3.67% to 3.79% lower cotton stalks leakage rate and a 5.65% to 6.30% lower cotton stalks breakage rate than the first-generation machine.As the land in Xinjiang is clay soil,soil bonding to cotton stalks pulling force F2 is larger,resulting in cotton stalks being more difficult to be pulled out of the machine at once.The test proved that the improved second-generation implements had a significant improvement in the cotton stalk-pulling effect because of the subsequent pulling interval CD.The test results verify the analysis results and the research results can provide a theoretical basis for the subsequent structural improvement and performance enhancement of the flexible cotton stalk-pulling machine,which is of reference significance for solving the problem that the cotton stalks are easily pulled and broken in Xinjiang,China.展开更多
Large amounts of crop stalks left in the field as a result of conservation agriculture cause blockage during no-till planting.To solve this issue,pure waterjet was used to cut off the maize stalks so that the rear fur...Large amounts of crop stalks left in the field as a result of conservation agriculture cause blockage during no-till planting.To solve this issue,pure waterjet was used to cut off the maize stalks so that the rear furrow opener could pass through without blockage.In this investigation,an experimental study on depth of cut,which was the main performance indicator of pure waterjet on cutting maize stalks,was presented.A full factorial design with 200 tests was implemented with respect to three operation parameters,that is traverse speed,waterjet pressure,and standoff distance were considered as variables.An analysis of variance(ANOVA)was carried out in order to determine the statistical significance of individual operation parameters.Using multilinear stepwise regression analysis,a model to predict the cut of depth from the predicted pure waterjet operation to cut maize stalks was then developed.All three operation parameters significantly influenced the cutting performance.Moreover,the results indicated that depth of cut increased with the increase of waterjet pressure,the decrease of traverse speed,and decrease in standoff distance.Waterjet pressure provided major contribution to depth of cut,followed by traverse speed,then standoff distance,which was demonstrated by both ANOVA and regression analysis.The experimental results showed that when the standoff distance was closer than 10 mm and waterjet pressure was 280 MPa,all maize stalks specimen could be cutoff thoroughly.With the consideration of field operating conditions,waterjet pressure of 280 MPa or higher and 10 mm to 15 mm standoff distance were recommended for maize stalks cutting.This analysis provided a realistic approach for the optimization of the ultra-high pressure pure waterjet parameters in maize stalks cutting,which could be used to relieve the occurrence of straw blockage in no-till planting.展开更多
At present,there are no harvesters specifically adapted to process peanuts after cutting stalks.In particular,methods for harvesting peanuts after cutting stalks have not been reported thus far.Therefore,to utilize pe...At present,there are no harvesters specifically adapted to process peanuts after cutting stalks.In particular,methods for harvesting peanuts after cutting stalks have not been reported thus far.Therefore,to utilize peanut stalks as feed when harvesting plastic-film-grown peanuts,and to improve industry benefits,a three-stage harvesting method is proposed herein.In view of the three-stage harvesting method,the peanut stalks are cut before digging,with the remaining peanut plants being shorter,thereby increasing the peanut pod-stalk ratio.To investigate the adaptabilities of existing harvesters in harvesting peanuts after cutting stalks,three types of peanut harvesters-the self-propelled pick-up combine harvester,trailed pick-up combine harvester,and peanut picker were used to conduct a comparative test on harvesting intact peanut plants and plants after cutting stalks.The loss,breakage and impurity rates were used as evaluation indicators.The loss rates of these three harvesters were 14.64%,16.44%and 1.33%;the breakage rates were 21.28%,21.92%and 20.00%,and impurity rates were 4.60%,8.76%and 9.06%.Analysis of variance showed that cutting stalks had a significant impact on the work qualities of the three harvesters(p<0.05).With regard to the loss rate,results revealed that:the two peanut combine harvesters could not be adapted to harvest peanut plants after cutting stalks.The three harvesters had good adaptability to harvest peanut plants after cutting stalks,considering the breakage rate;however,based on the impurity rate,the three harvesters could not be adapted to harvest peanut plants after cutting stalks.The losses of the two combine harvesters consisted mainly of dropped and missed picking,with the sum of the losses accounting for 99.87%and 97.99%of the total losses of the two harvesters,respectively;this suggests that the drum pickup of the combine harvesters could not adapt to harvesting the peanut after cutting stalks.The breakage rates of the three harvesters were considerably reduced,suggesting that the pod picking devices of the three harvesters were suitable for harvesting the peanut after cutting stalks;the impurity rates of the three harvesters were considerably increased,indicating that the pod picking and cleaning devices of the three harvesters were not suitable for harvesting peanut after cutting stalks.To improve the adaptabilities of the harvesters,it is suggested that the speed of pickup elastic tooth,lateral spacing between adjacent elastic teeth,concave screen hole size of pod picking device,the structure and motion parameters of cleaning device should be optimized.The results of this study provide a reference for the development and improvement of peanut harvesters suitable for harvesting peanuts after the cutting of stalks.展开更多
When the citrus harvesting robot harvests citruses,the mechanical properties of citrus stalks have an important influence on the success rate of the citrus harvesting robot.During the harvesting,the maturity of citrus...When the citrus harvesting robot harvests citruses,the mechanical properties of citrus stalks have an important influence on the success rate of the citrus harvesting robot.During the harvesting,the maturity of citrus fruits not only determined the harvesting time of citrus fruits but also affected the mechanical properties of citrus fruit stalks.In this study,the changes in the cutting force of citrus fruit stalks were described during the maturity of citrus fruits,and the effect of the maturity on the cutting force of stalks was clarified,so as to determine the harvesting time with the minimum cutting force required for harvesting citrus fruits by the harvesting robot.During the maturity,the relevant parameters of fruit maturity,such as the hardness,pH,and solid solution content of citrus fruits,were monitored.The results showed that there is a significant correlation between the hardness,pH,the solid solution content of citrus fruits,and the cutting force of citrus fruit stalks during maturity.The single-factor mechanical model of hardness,pH,solid solution content of citrus fruits,and the cutting force of citrus fruit stalks were established based on the data of 2019,which were verified through tests in 2020.The test results are as follows:during the ripening period of citrus fruits,the fruit hardness varies in the range of 0.13-0.31 MPa,the hardness changes by 0.02 MPa,and the cutting force changes by about 2.0-6.0 N;the pH of the citrus fruits changes in the range of 2.8-4.0,and the cutting force changes by about 1.5-2.2 N for every 0.1 change in the pH;the variation range of fruit solid solution content is 6.5%-9.0%,and for every 0.2%change in solid solution,the cutting force of citrus fruit stalks changes by about 1.25-2.0 N.The mechanical models can predict the cutting force required to cut off citrus fruit stalks according to the relevant parameters of citrus fruit maturity and can provide a reference for effectively evaluating the required cutting force.展开更多
Cotton stalks(CS)are lignocellulosic agricultural by-products,a potential source for biogas production,but pretreatment must be considered since hydrolysis is the rate-limiting stage for lignocellulosic biomass substr...Cotton stalks(CS)are lignocellulosic agricultural by-products,a potential source for biogas production,but pretreatment must be considered since hydrolysis is the rate-limiting stage for lignocellulosic biomass substrates.This study investigates the feasibility of mechanical pretreatment of CS to enhance methane production.Batch anaerobic digestion of CS samples with particle sizes ranging from 0.5 to 65 mm was carried out in 1 L eudiometer batch digesters for 48 days at 37◦C.Results showed that methane yield was inversely proportional to particle size,and the quality of biogas was good(54.0-55.2%CH_(4)).Significant increases in methane yield were observed with 20.3%and 26%for samples with a particle size of 3 mm and 0.5 mm,respectively,compared to untreated CS.The coefficient of anaerobic energy turnover was relatively low(20.2-25.5%).Reduction of the CS particle size to 3 mm or less is recommended to achieve effective methane conversion and decrease the retention time in an anaerobic digester from 31 to about 25 days.However,to offset the high energy demand required for grinding,further research should be conducted in combining size reduction with chemical and physicochemical pretreatment.展开更多
Drying characteristics,energy consumption and drying kinetics modeling of crashed cotton stalks dried in a microwave dryer were investigated in this research.A microwave dryer with an output power of 1000 W and 2450 M...Drying characteristics,energy consumption and drying kinetics modeling of crashed cotton stalks dried in a microwave dryer were investigated in this research.A microwave dryer with an output power of 1000 W and 2450 MHz was employed,and the effects of material load ranging from 50 g to 250 g on drying time,drying rate,drying efficiency and specific energy consumption were evaluated.The results showed that drying rate decreased with drying duration.A rising rate period was followed by a falling rate period and the overall drying process occurred in the falling rate period.Six mathematical models were used to fit the drying rates data of crashed cotton stalks,and Midilli et al.model was found the best prediction model by comparing R2,RMSE andχ^(2)values between experimental and predicted moisture ratios.With decrease in material load from 250 g to 50 g,effective moisture diffusivity increased from 2.8668×10^(-8)m^(2)/s to 7.9817×10^(-8)m^(2)/s.Results also indicated that drying efficiency and specific energy consumption significantly increased with the increase of the material load.Average drying efficiency and specific energy consumption varied in the range of 7.52%-19.78%and 12.49-35.90 MJ/kg water,respectively.There were a lowest energy consumption of 10.99 MJ/kg water and a highest drying efficiency of 17.13%at the material load level of 250 g.展开更多
As one of the foundational research areas in agricultural engineering,the study of agricultural materials includes an important branch:mechanics properties of crop stalks.This branch is now widely associated with desi...As one of the foundational research areas in agricultural engineering,the study of agricultural materials includes an important branch:mechanics properties of crop stalks.This branch is now widely associated with design and improvement of agricultural equipment,breeding of new species,and development of reinforced composites.This article presents an overview of research on mechanics properties of crop stalks,including the mechanics measurement experiments,mechanics model and theory,microstructure and composition,and mechanics simulation experiments.The current research relies mainly on the mechanics theory of engineering material,neglects the fact that crop stalk is a biological material with complex structure,anisotropy,viscoelasticity and rheology.In addition,some simulation experiments are conducted in idealized conditions,beyond the application.Hence,the paper proposes to create new material models for crop stalks,conduct more practical and effective simulation experiments,and promote cooperation in interdisciplinary studies for the development of mechanics properties of crop stalks in the future research.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.42177431 and No.U20A2086)the Beijing Natural Science Foundation(International Scientists Project,Grant No.IS24033)+3 种基金the joint research project between UniMAP and TIIAME NRU(Grant No.INTERES 9008-00064)the series training courses(Belt&Road Talent Exchange Program,Grant No.DL2021108001L)for academic writing guidance that conducted by Prof.Harold J.Annegarnthe support from China Scholarship CouncilTYSP program to the international students and scholars。
文摘One of the solutions to the global warming risk and other climate issues is to concentrate on research and development of utilizing biomass as a fossil fuel alternative.The current estimate of cotton residue waste in the world is about 50 million tons.This massive volume of biomass waste should be turned into clean energy to avert burning the stalks in open fields after cotton harvesting.Therefore,harmful emissions such as CO_(2) will be reduced.This study aims to investigate the published literature to comprehend the bioenergy production from the thermal treatment of cotton stalks,including combustion,pyrolysis,carbonization,torrefaction,liquefaction,and gasification.Furthermore,the future outlook,utilization,and prospective challenges of agricultural biomass for biofuel production are discussed.According to the literature,biochar and bio-oil derived from cotton stalks have high heating values of about 27.5 and 37.2 MJ·kg~(–1),respectively.These values are double those of cotton stalk raw materials,which make it a good candidate for bioenergy production.This article offers valuable insight into cotton stalk utilization via thermochemical treatment and provides a solid reference for researchers,policymakers,and other stakeholders in this field.
基金Supported by National Special Fund for Scientific Research in Public Welfare Trade(Agriculture)(200803033-B0602-01)Project of Hebei Province Scientific and Technological Department(10221019)+1 种基金Project of Qinghuangdao City Science and Technology Burea of Hebei Province(201001A152)Foundation of Education Committee of Hebei Province(2003308)~~
文摘[Objective] The study aimed at reducing the economic cost in feeding Tenebrio molitor and improving the utilization ratio of corn stalks.[Method] The effects of different proportions of corn stalks on the weigh of Tenebrio molitor and the contents of crude protein,crude fat,Ca,P,dry matter and crude ash in the half-dry matter of Tenebrio molitor had been studied in the laboratory.[Result] Compared with the recipes of all wheat bran and pure fine fodder,feeding Tenebrio molitor by applying 30%-60% of corn stalks could significantly improve the content of crude protein in the half-dry materials of Tenebrio molitor,but it was detrimental to the improvement in weight of Tenebrio molitor and the accumulation of crude fat.To be specific,the recipe V（50% of corn stalks ＋ 50% of fine fodder） was beneficial to the accumulation of dry matter and crude ash.The recipe VII（70% of corn stalks ＋ 30% of fine fodder） and the recipe VIII（70% of corn stalks treated with Guangda feed leaven ＋ 30% of fine fodder） were beneficial to the accumulation of crude protein,Ca and P.There were differences among the influences of corn stalks in different treatments on the crude protein and other nutrition indicators of Tenebrio molitor.[Conclusion] Appropriately applying corn stalks can improve the accumulation of the crude protein,crude ash,dry matter,Ca and P of Tenebrio molitor but was detrimental to the growth and development of Tenebrio molitor and the accumulation of crude fat.
基金Supported by Science and Technology Innovation Plan for Outstanding Scholars in Henan Province(2014KJCXJCRC015)~~
文摘[Objective] This study aimed to study the adsorption performance of activated carbon prepared from corn stalks. [Methed] With granular activated carbon prepared from corn stalks as research object, adsorption performance simulation test equipment was set up to investigate the adsorption performance of the prepared activated carbon for methanol by static weight method. In addition, the effects of adsorption bed structure, activated carbon particle size in adsorption bed, addition amount of graphite powder in activated carbon and modified activated carbon on systematic adsorption performance were studied. [Result] Under conditions of same activated carbon and same adsorption temperature, the adsorption performance of new adsorption bed A （installed with finned diaphragm adsorbate tubes） was signifi- cantly better than that of unmodified adsorption bed B. Compared with adsorption bed B, adsorption bed A took 5 min shorter to reach the adsorption amount of 0.22 g/g. Under the same adsorption temperature, the adsorption performance of bed loaded with different-particle size activated carbon was significantly better than that loaded with same-particle size activated carbon. The bed loaded with different-particle size activated carbon took 16 min shorter to reach the adsorption capacity of 0.22 g/g compared with the bed loaded with same-particle size activated carbon. Adding proper amount of graphite powder in activated carbon could enhance the thermal conductivity and strengthen the adsorption properties. The optimum addition amount of graphite powder was 20% of the total amount of activated carbon. Com- pared with that of the control, the adsorption performance of activated carbon soaked by weak acidic solution was significantly improved. It took 3 min shorter to reach 87.1% of the equilibrium adsorption amount. [Conclusion] This study will provide reference for optimizing structural design of adsorption bed and adsorption refrigeration system.
基金Supported by the Special Fund for Crop Breeding of Sichuan Provincial Department of Education,China (2006LD006)the Rapeseed Breeding Research Program of Science & Technology Department of Sichuan Province,China (2006YZGG-5-5)~~
文摘[Objective] To study the correlation between the biomechanical properties of rape stalks and rape stem lodging. [Method] Through axial compression tests to the stalks of 4 different rape varieties, the change rules of maximum stem bearing ca- pacity, maximum compressive strength, elastic modulus and moment of inertia along plant height were analyzed, as well as the effect of different varieties and water contents on the biomechanical property indices of rape stalks. [Result] The maximum loads of rape stalks presented liner decrease trend along with the increase of stem height, and all reached the maximums below the height of 50 cm. The maximum stem compressive strength and elastic modulus of the 4 varieties were increased with ascending height, but in a slow rate with small change, thus the modulus of e- lasticity could be considered as unchanged. The maximum bearing capacity, maxi- mum compressive strength and elastic modulus of dry rape stalks were higher than wet stalks, indicating that the water contents of rape stalks had significant effect on their mechanical properties. According to the actual lodging situations in filed, stalks of variety No. 1 owned the worst biomechanical properties and lodging degree, while the biomechanical properties of No. 6 and F5 were better than No. 1 and No. 9, and they also had stronger lodging-resistance. [Conclusion] The study provides parameters and bases for the design of mechanized production and mechanical deep processing of crops, and can better reveal the physical natures of organisms. The methods used in this study can also be used to screen excellent crop stalks.
基金Supported by National Major Water Project of Eleventh Five-Year Plan(2008ZX07105002)~~
文摘We undertook a pyrolysis research on garlic stalks to solve its difficulty in use. We found that the inorganic salts in biomass played an important role in catalytic pyrolysis. Moreover, we studied the pyrolysis behavior under catalyst and catalyst-free conditions. The results showed that the weightlessness rate of garlic stalks was the highest at 550 ℃ under catalyst-free condition. The oil production rate increased with the increase of temperature and reached the peak at 550 ℃. Subsequently, as the temperature increased, the secondary cracking was intensified and oil production rate was decreased. The oil production rate increased significantly （almost 15%） under catalysis of KOH. However, the oil production rate was the highest at 500-600℃. What＇s more, we found that KOH played a major role in promoting decomposition of surface skin cells and subcutaneous fibrous layer of garlic stalks.
文摘Pretreatment of lespedeza stalks by steam explosion has been studied. The results indicate that steam-exploded pretreatment has strong effects on physical features, morphology, crystallinity, and composition of lespedeza stalks as shown by scanning electron microscopy （SEM）, infrared （IR）, and X-ray diffraction spectrometry methods. After steam explosion, the cellulose and lignin contents of lespedeza stalks varied only slightly, but the hemicellulose content had decreased from 29.34% to 7.48%. The cellulose obtained by steam-exploded pretreatment had a higher degree of crystallinity than that of the raw material. At the explosion condition of 2.25 MPa and 4 min, lignocellulose is easier to hydrolyze by enzyme than the original lignocellulose. The concentration of reduced sugar in the hydrolyzate liquid increased from 71.77 to 162.84 g·L^-1.
基金This research was financially supported by the National Natural Science Foundation of China(No.21878292,No.21606240,No.21878314)K.C.Wong Education Foundation(No.GJTD-2018-04)the Strategic Priority Research Program of Chinese Academy of Science(No.XDA21060300).
文摘It is very difficult to directly spin the lignocellulose without pretreatment.Ionic liquids(ILs)are promising solvent to dissolve lignocellulose to prepare cellulose fiber.However,the degree of cellulose polymerization(DP)is reduced when lignocellulose is dissolved in ILs,and the lignin removal rate is low.The elongation at break and tensile strength of the fibers obtained by spinning the lignocellulose dissolved in ILs are poor.In this paper,preparing cellulose fiber directly from lignocellulose based on dissolving corn stalk via[C4mim]Cl-L-arginine binary system is achieved.It shows that the removal rate of lignin can reach 92.35%and the purity of cellulose can reach 85.32%after corn stalk was dissolved at 150℃C for 11.5 h when the mass fraction of arginine is 2.5%.The elongation at break of fiber reached 10.12%and the tensile strength reached 420 MPa.It is mainly due to the fact that L-arginine not only inhibits the degradation of cellulose but also promotes the delignination.Without any pulping or pretreatment,preparing cellulose fibers via direct dissolution and extrusion may provide a simple and effective way to prepare many novel cellulose materials.
基金supported bythe National Natural Science Foundation of China.
文摘Sweet potato(Ipomoea batatas Lam.)leaf stalks were cut into 20 cm length,and stored at 20,6,and 2℃.The respiration rate,ethylene production,ascorbic acid,free amino acid,total chlorophyll content,freshness,and shelf life were determined during storage to investigate the effect of storage temperatures on the quality and physiological responses in sweet potato leaf stalks.Wound responses were observed as high respiration rate and ethylene production immediately after cutting.Sweet potato leaf stalks were found to be sensitive to chilling injury manifested as browning and water-soaking on the surface at 2℃.In contrast,sweet potato leaf stalks were susceptible to senescence,exhibited by etiolating and yellowing,at 20℃.Loss in weight and chlorophyll was minimized under low temperatures.High temperatures also caused the accumulation of amino acids with a significant loss of ascorbic acid and chlorophyll.Sweet potato leaf stalks had a storage life of 16 days at 6℃,8 days at 2℃,and 6 days at 20℃,respectively.
文摘Lespedeza stalks were subjected to steam pretreatment at 210℃ for some steaming time before simultaneous saccharification and fermentation （SSF）. Cellulose-derived glucose was extensively utilized by yeast during SSE The ethanol yields after steam pretreatment of the lespedeza stalks at 210℃ were 59.3%, 72.8% and 62.2% of the theoretically expected values when the steaming times were 2, 4 and 6 min, respectively. The highest yield from α-cellulose was 92.7% of the theoretical value. Steam explosion pretreatment of lespedeza stalks increased ethanol yields by a factor of 4.4, from 16.4% （untreated） to 72.8% （steam explosion pretreated）.
基金Supported by Agricultural Research Project of Shaanxi Provincial Science and Technology Department(2012.k02-10)Innovation and Entrepreneurship Training Project of University Students in Shaanxi Province(1252)Special Funds of Ecology for Construction of High-level University in Shaanxi Province(2012SXTS03)
文摘In order to reduce the economic costs for breeding Tenebrio molitor L. and increase the utilization rate of corn stalk, with corn, wheat bran and corn stalk as the raw materials, 13 different compound feed were designed by Minitab （R） 15.1.0.0. The design was then divided into two groups based on addition or without addition of vegetable leaves to study the effects of compound feed and vegetable leaves on growth and de- velopment of T. molitor. The results showed that body weight, duration, crude protein content and pupation rate of larvae and emergence rate of adults were significantly affected by compound feed and vegetable leaves （ P 〈 0.05）. The larvae bred with feed 5 had the largest body weight, with the shortest duration; the larvae bred with feed 3 had the highest pupation rate; the larvae bred with feed 7 had the highest crude protein content; the adult bred with feed 9 had the largest emergence rate. Overall breeding effect of feed 7 ＋ vegetable leaves was better than any other groups, with ideal indicators, higher utilization rate and lower breeding cost. Its formula was w （wheat bran） = 33.33%, w （corn） = 33.33%, w （corn stalks） = 33.33%. Therefore, the growth of T. molitorwas significantly affected by feed types, and feed 7 ＋ vegetable leaves could be promoted in the production.
基金supported by the National Key Research and Development Program for Grain High yield Science and Technology Innovation Project of China (2016YFD0300307,2016YFD0300209,2017YFD0301704,2018YFD0301206).
文摘Maize stalk lignin and cellulose contents are linked to lodging resistance,disease resistance,feed quality and ethanol conversion efficiency.After the six-leaf stage of maize(V6),these constituents are biosynthesized and accumulated under the control of related enzymes and genes.However,the key enzymes,critical MYB transcription factors,and their dynamic alterations pattern under natural field circumstances are still unknown.Hence,we selected five cultivars with significant differences in lignocellulose content and lodging resistance as testing materials,performed field experiments for two years,and investigated the dynamics of lignin and cellulose content,related enzyme concentrations,and gene expression levels in the 3^(rd) and 5^(th) internodes above the ground after V6.The results showed that lignin and cellulose content increased after V6,stabilizing during the silking stage.This study identified COMT(caffeic acid 3-Omethyltransferase),TAL(tyrosine ammonia-lyase)and PAL(phenylalanine ammonia-lyase)as the key enzymes of lignin biosynthesis,while ZmCOMT,ZmCesA10 and ZmCesA8 were identified as essential genes.ZmMYB8,ZmMYB31 and ZmMYB39 were involved in regulating the expression of genes related to lignin synthesis,with ZmMYB31 potentially acting as a key negative regulator,while ZmMYB39 and ZmMYB8 acting as positive regulators.The study also found that around 14 d after V6 was a critical stage for regulating lignocellulose synthesis in the 3^(rd) to 5^(th) basal internode.This provides a theoretical foundation for developing regulatory techniques and breeding new cultivars to enhance lodging and disease resistance as well as the utility of maize stalks.
文摘Cellulose biomass is being investigated as a potential substrate for bioethanol production. Cassava stalks were successfully converted to ethanol by fermentation using Saccharomyces cerevisiae TISTR5048, S. cerevisiae KM1195, S. cerevisiae KM7253 and co-culture of S. cerevisiae TISTR5048 and Candida tropicalis TISTR5045. The objective of this study was to assess the ethanol production from cassava stalks by dilute-acid pretreatment and enzymatic hydrolysis that were convertible into ethanol by mono-culture and co-culture of yeast strain. Cassava stalks 1.5% （w/v） in 0.1 M sulfuric acid was pretreated for 30 min at 135 ℃ under the pressure of 15 lb/inch2. The pretreated cassava stalk suspensions were neutralized to pH 5.5 for saccharification process. The enzyme solution （a-amylase, amyloglucosidase, cellulase, xylanase and pectinase solubilized in buffer pH 5.0） was used for hydrolysis ofpretreated cassava stalk at 50 ℃ for 24 h. The hydrolyaste was supplemented with additional nutrients. The culture was incubated at 30 ℃. The pretreatment of the stalk with dilute-acid resulted sugar yield of 0.57 g/g dry matter from enzymatic hydrolysis, which was higher than dilute-alkaline-pretreated and distilled water-pretreated stalk. The sugar hydrolysate was bioconverted to ethanol with separate hydrolysis and fermentation （SHF） and simultaneous saccharification and fermentation （SSF）. The highest ethanol yields of 98.43% and 95.29% were obtained in SHF and SSF, respectively by S. cerevisiae KM1195. The fermentation time of SSF process was 24-32 h shorter than that of the SHF （= 56 h）, but not significantly leading to difference in ethanol production （5.42 g/L-6.22 g/L for SSF; 5.9 g/L-6.23 g/L for SHF）.
基金supported by the intramural research program of the U.S.Department of Agriculture,National Institute of Food and Agriculture,Biobased Economy Through Biobased Products,under Award#2023-68016-40132.
文摘This study explores a novel method for processing cotton stalks—an abundant agricultural byproduct—into long strips that serve as sustainable raw material for engineered bio-based panels.To evaluate the effect of raw material morphology on panel’s performance,two types of cotton stalk-based panels were developed:one using long strips,maintaining fiber continuity,and the other using ground particles,representing conventional processing.A wood strand-based panel made from commercial southern yellow pine strands served as the control.All panels were bonded using phenol-formaldehyde resin and hot-pressed to a target thickness of 12.7 mm and density of 640 kg/m^(3).Their mechanical and physical properties were evaluated through internal bond,bending,thickness swelling,and water absorption tests.Both cotton stalk-based panels showed improved bonding performance compared to the control.The internal bond of the strip-based panel was nearly four times higher than that of the control,while the particlebased panel exceeded it by a factor of two.The strip-based panel showed approximately 15% lower bending stiffness than the wood strand-based panel,yet it surpassed it in load-carrying capacity by 5%.In contrast,the particleboard showed significantly lower bending performance than the strip-based and control panels,despite particle processing being a more conventional method.Both cotton stalk-based panels exhibited higher water absorption and thickness swelling than the wood strand panel.Overall,cotton stalk-based panels—particularly those using strip processing—show promisingmechanical properties,suggesting potential applications in sheathing,furniture,and interior paneling.However,improvements in dimensional stability are needed for broader use.
基金This work was supported by the Key R&D Project of Xinjiang Uygur Autonomous Region(Grant No.2022B02022-2)the Key R&D Project of Xinjiang Uygur Autonomous Region(Grant No.2022B02023-3)+3 种基金the Agricultural Science and Technology Promotion and Service Project of Xinjiang Uygur Autonomous Region(Grant No.NTFW-2022-17)the Tianshan Innovation Team Project of Xinjiang Uygur Autonomous Region(Grant No.2020D14037)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(Grant No.2019D01A45)the National Natural Science Foundation of China(Grant No.51865058).
文摘In Xinjiang,in the process of whole stalk harvesting of cotton stalks,there is a problem that the cotton stalks are easily pulled off,and there is an urgent need to develop flexible stalk-pulling machines.Through literature,patent summary,and field research,it is found that domestic researchers have designed many kinds of machines for the problem of easy breaking of cotton stalks,but there is no flexible cotton stalk-pulling machine for the time being.In this study,two flexible cotton stalk-pulling machines were intended to address the problem of easy breakage of cotton stalks.On the basis of the first-generation machine,the design of the second-generation machine was improved.In order to further improve the operational performance of the flexible cotton stalks pulling tools,the operational mechanism of the core working parts of the tools was analyzed and a comparative test was done in a large field.Analysis and the comparative tests proved that improving the clamping working stroke s of the stalk-pulling components can effectively reduce the cotton stalks leakage rate.By using a flexible clamping process,a part of the deformation of cotton stalks can be transferred to the flexible material.To a certain extent,the deformation length L of the contact surface between the cotton stalk and the stalk pulling part is reduced,and the deformation displacementΔy is correspondingly lower.The toughness of the cotton stalk is not significantly decreased and the cotton stalk does not break easily.The improved second-generation machine has a 3.67% to 3.79% lower cotton stalks leakage rate and a 5.65% to 6.30% lower cotton stalks breakage rate than the first-generation machine.As the land in Xinjiang is clay soil,soil bonding to cotton stalks pulling force F2 is larger,resulting in cotton stalks being more difficult to be pulled out of the machine at once.The test proved that the improved second-generation implements had a significant improvement in the cotton stalk-pulling effect because of the subsequent pulling interval CD.The test results verify the analysis results and the research results can provide a theoretical basis for the subsequent structural improvement and performance enhancement of the flexible cotton stalk-pulling machine,which is of reference significance for solving the problem that the cotton stalks are easily pulled and broken in Xinjiang,China.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest from the Ministry of Agriculture,China(Grant No.201503136).
文摘Large amounts of crop stalks left in the field as a result of conservation agriculture cause blockage during no-till planting.To solve this issue,pure waterjet was used to cut off the maize stalks so that the rear furrow opener could pass through without blockage.In this investigation,an experimental study on depth of cut,which was the main performance indicator of pure waterjet on cutting maize stalks,was presented.A full factorial design with 200 tests was implemented with respect to three operation parameters,that is traverse speed,waterjet pressure,and standoff distance were considered as variables.An analysis of variance(ANOVA)was carried out in order to determine the statistical significance of individual operation parameters.Using multilinear stepwise regression analysis,a model to predict the cut of depth from the predicted pure waterjet operation to cut maize stalks was then developed.All three operation parameters significantly influenced the cutting performance.Moreover,the results indicated that depth of cut increased with the increase of waterjet pressure,the decrease of traverse speed,and decrease in standoff distance.Waterjet pressure provided major contribution to depth of cut,followed by traverse speed,then standoff distance,which was demonstrated by both ANOVA and regression analysis.The experimental results showed that when the standoff distance was closer than 10 mm and waterjet pressure was 280 MPa,all maize stalks specimen could be cutoff thoroughly.With the consideration of field operating conditions,waterjet pressure of 280 MPa or higher and 10 mm to 15 mm standoff distance were recommended for maize stalks cutting.This analysis provided a realistic approach for the optimization of the ultra-high pressure pure waterjet parameters in maize stalks cutting,which could be used to relieve the occurrence of straw blockage in no-till planting.
基金This study was financially supported by the National Natural Science Foundation of China(51905282)the Chinese Academy of Agricultural Sciences basic research business fee special(S201917,S202011-02)+1 种基金the China Agriculture Research System(CARS-13-harvest mechanization)the Green farming and mechanization of the underground fruits harvesting innovation project of the Chinese Academy of Agricultural Sciences。
文摘At present,there are no harvesters specifically adapted to process peanuts after cutting stalks.In particular,methods for harvesting peanuts after cutting stalks have not been reported thus far.Therefore,to utilize peanut stalks as feed when harvesting plastic-film-grown peanuts,and to improve industry benefits,a three-stage harvesting method is proposed herein.In view of the three-stage harvesting method,the peanut stalks are cut before digging,with the remaining peanut plants being shorter,thereby increasing the peanut pod-stalk ratio.To investigate the adaptabilities of existing harvesters in harvesting peanuts after cutting stalks,three types of peanut harvesters-the self-propelled pick-up combine harvester,trailed pick-up combine harvester,and peanut picker were used to conduct a comparative test on harvesting intact peanut plants and plants after cutting stalks.The loss,breakage and impurity rates were used as evaluation indicators.The loss rates of these three harvesters were 14.64%,16.44%and 1.33%;the breakage rates were 21.28%,21.92%and 20.00%,and impurity rates were 4.60%,8.76%and 9.06%.Analysis of variance showed that cutting stalks had a significant impact on the work qualities of the three harvesters(p<0.05).With regard to the loss rate,results revealed that:the two peanut combine harvesters could not be adapted to harvest peanut plants after cutting stalks.The three harvesters had good adaptability to harvest peanut plants after cutting stalks,considering the breakage rate;however,based on the impurity rate,the three harvesters could not be adapted to harvest peanut plants after cutting stalks.The losses of the two combine harvesters consisted mainly of dropped and missed picking,with the sum of the losses accounting for 99.87%and 97.99%of the total losses of the two harvesters,respectively;this suggests that the drum pickup of the combine harvesters could not adapt to harvesting the peanut after cutting stalks.The breakage rates of the three harvesters were considerably reduced,suggesting that the pod picking devices of the three harvesters were suitable for harvesting the peanut after cutting stalks;the impurity rates of the three harvesters were considerably increased,indicating that the pod picking and cleaning devices of the three harvesters were not suitable for harvesting peanut after cutting stalks.To improve the adaptabilities of the harvesters,it is suggested that the speed of pickup elastic tooth,lateral spacing between adjacent elastic teeth,concave screen hole size of pod picking device,the structure and motion parameters of cleaning device should be optimized.The results of this study provide a reference for the development and improvement of peanut harvesters suitable for harvesting peanuts after the cutting of stalks.
基金supported by the Basic Science and Frontier Technology Research(General)Project(Grant No.cstc2018jcyjAX0071)of Chongqing,Chinathe Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202201104),China.
文摘When the citrus harvesting robot harvests citruses,the mechanical properties of citrus stalks have an important influence on the success rate of the citrus harvesting robot.During the harvesting,the maturity of citrus fruits not only determined the harvesting time of citrus fruits but also affected the mechanical properties of citrus fruit stalks.In this study,the changes in the cutting force of citrus fruit stalks were described during the maturity of citrus fruits,and the effect of the maturity on the cutting force of stalks was clarified,so as to determine the harvesting time with the minimum cutting force required for harvesting citrus fruits by the harvesting robot.During the maturity,the relevant parameters of fruit maturity,such as the hardness,pH,and solid solution content of citrus fruits,were monitored.The results showed that there is a significant correlation between the hardness,pH,the solid solution content of citrus fruits,and the cutting force of citrus fruit stalks during maturity.The single-factor mechanical model of hardness,pH,solid solution content of citrus fruits,and the cutting force of citrus fruit stalks were established based on the data of 2019,which were verified through tests in 2020.The test results are as follows:during the ripening period of citrus fruits,the fruit hardness varies in the range of 0.13-0.31 MPa,the hardness changes by 0.02 MPa,and the cutting force changes by about 2.0-6.0 N;the pH of the citrus fruits changes in the range of 2.8-4.0,and the cutting force changes by about 1.5-2.2 N for every 0.1 change in the pH;the variation range of fruit solid solution content is 6.5%-9.0%,and for every 0.2%change in solid solution,the cutting force of citrus fruit stalks changes by about 1.25-2.0 N.The mechanical models can predict the cutting force required to cut off citrus fruit stalks according to the relevant parameters of citrus fruit maturity and can provide a reference for effectively evaluating the required cutting force.
文摘Cotton stalks(CS)are lignocellulosic agricultural by-products,a potential source for biogas production,but pretreatment must be considered since hydrolysis is the rate-limiting stage for lignocellulosic biomass substrates.This study investigates the feasibility of mechanical pretreatment of CS to enhance methane production.Batch anaerobic digestion of CS samples with particle sizes ranging from 0.5 to 65 mm was carried out in 1 L eudiometer batch digesters for 48 days at 37◦C.Results showed that methane yield was inversely proportional to particle size,and the quality of biogas was good(54.0-55.2%CH_(4)).Significant increases in methane yield were observed with 20.3%and 26%for samples with a particle size of 3 mm and 0.5 mm,respectively,compared to untreated CS.The coefficient of anaerobic energy turnover was relatively low(20.2-25.5%).Reduction of the CS particle size to 3 mm or less is recommended to achieve effective methane conversion and decrease the retention time in an anaerobic digester from 31 to about 25 days.However,to offset the high energy demand required for grinding,further research should be conducted in combining size reduction with chemical and physicochemical pretreatment.
基金the Public Interest of Agricultural biomass characteristics and Sharing platform technology research(project number:201003063).
文摘Drying characteristics,energy consumption and drying kinetics modeling of crashed cotton stalks dried in a microwave dryer were investigated in this research.A microwave dryer with an output power of 1000 W and 2450 MHz was employed,and the effects of material load ranging from 50 g to 250 g on drying time,drying rate,drying efficiency and specific energy consumption were evaluated.The results showed that drying rate decreased with drying duration.A rising rate period was followed by a falling rate period and the overall drying process occurred in the falling rate period.Six mathematical models were used to fit the drying rates data of crashed cotton stalks,and Midilli et al.model was found the best prediction model by comparing R2,RMSE andχ^(2)values between experimental and predicted moisture ratios.With decrease in material load from 250 g to 50 g,effective moisture diffusivity increased from 2.8668×10^(-8)m^(2)/s to 7.9817×10^(-8)m^(2)/s.Results also indicated that drying efficiency and specific energy consumption significantly increased with the increase of the material load.Average drying efficiency and specific energy consumption varied in the range of 7.52%-19.78%and 12.49-35.90 MJ/kg water,respectively.There were a lowest energy consumption of 10.99 MJ/kg water and a highest drying efficiency of 17.13%at the material load level of 250 g.
基金the National High Technology Research and Development Program of China(2012AA10A504)Key R&D Project of China(2016YFD0701201)。
文摘As one of the foundational research areas in agricultural engineering,the study of agricultural materials includes an important branch:mechanics properties of crop stalks.This branch is now widely associated with design and improvement of agricultural equipment,breeding of new species,and development of reinforced composites.This article presents an overview of research on mechanics properties of crop stalks,including the mechanics measurement experiments,mechanics model and theory,microstructure and composition,and mechanics simulation experiments.The current research relies mainly on the mechanics theory of engineering material,neglects the fact that crop stalk is a biological material with complex structure,anisotropy,viscoelasticity and rheology.In addition,some simulation experiments are conducted in idealized conditions,beyond the application.Hence,the paper proposes to create new material models for crop stalks,conduct more practical and effective simulation experiments,and promote cooperation in interdisciplinary studies for the development of mechanics properties of crop stalks in the future research.
