Determination of Physical, Mechanical and Fire Retardancy Properties of Innovative Particleboard Made from Corn Stalk (Zea mays L.) Particles

The demand for particleboard is increasing along with economic and population growth.However,two major barriers to the manufacture of particleboard are a shortage of raw materials(woodchips)and the emission of formaldehyde from conventional adhesives.Agricultural by-products such as corn stalks contain an abundance of renewable lignocellulosic fiber.This study evaluates the effect of citric acid as a natural adhesive and fire retardant addition on the physical,mechanical,and fire retardancy properties of particleboards fabricated from corn stalks.A cost-effective and inorganic salt,calcium carbonate,was tested to enhance the fire retardancy.Ammonium dihydrogen phosphate was also considered as a comparative control.Particleboards with the addition of calcium carbonate was pretreated with sodium chloride.The particleboards were pressed for 10 min at 200℃.Japanese Industrial Standard JIS A 5908:2022 was used as the benchmark for the physical and mechanical tests.Fire retardancy was dynamically tested by simulating a Bushfire Attack Level of 19 kW/m^(2).The particleboard with 25 wt%citric acid had superior mechanical properties and complied with the JIS A 5908 standard for Type 13 base particleboard.Particleboard with the addition of calcium carbonate(5%and 10%)showed significantly delayed pyrolysis time.

Effects of Whole-plant Corn Silage and Whole-plant Wheat Silage on Growth Performance and Economic Benefits of Beef Cattle

[Objectives]This study was conducted to study the effects of whole-plant corn silage and whole-plant wheat silage on growth performance and economic benefits of beef cattle.[Methods]Thirty Simmental crossbred cattle were selected and randomly divided based on their weight into two groups,15 cows in each group,with an average weight of 398 kg.Each group was fed the same concentrated feed,and the whole-plant corn silage and wheat silage were fed as roughage feed,respectively.The experimental period was 90 d.[Results](1)There was no significant difference in the initial weight of beef cattle between test group 1 and test group 2(P>0.05).Compared with group 2,group 1 had a higher final weight,average daily gain,and dry matter intake of beef cattle,without significant differences(P>0.05).Group 1 was 0.58%,1.99%,and 1.43%higher than group 2,respectively.The feed-to-gain ratio of test group 1 decreased by 0.54%compared with test group 2(P>0.05),with no significant difference therebetween.(2)The economic benefit of group 1 was 11.45 yuan/(day·capita),while the economic benefit of group 2 was 2.41 yuan/(day·capita),and group 1 was 9.04 yuan/(day·capita)higher than group 2.[Conclusions]Whole-plant corn silage for feeding beef cattle has the advantages of good weight gain and low breeding cost,and can be popularized in beef cattle fattening.

Improvement of Methane Production from Corn Stalk for Whole Slurry Anaerobic Co-digestion Under Hydrothermal Wastewater Pretreatment

Corn stalk hydrothermal wastewater(CSHW)was used as a pretreatment for whole-slurry anaerobic co-digestion instead of conventional acid pretreatment.CSHW pretreatment was conducted at 20℃,35℃and 50℃for 3,6 and 9 h,after which all experimental groups were digested at 35℃for 24 days.This pretreatment method efficiently broke the lignocellulose structure of the corn stalk.Different from the volatile fatty acids(VFAs)content,the pH and RS contents were relatively higher than those of the control during the pretreatment process.Furthermore,the highest methane production[185.03 mL•g-1 VS(volatile solid)]was achieved at 55.46%under 35℃in 6 h,which was higher than that of the normal corn stalk anaerobic digestion.The VFAs contents and pH increased compared to CK upon the addition of NaOH to adjust pH,and the RS content also increased slightly due to the degradability of lignocellulose during the whole-slurry anaerobic co-digestion.This work provided a potential method to sustainably treat wastewater and improve fermentation performance.

Effects of Feeding Corn Stalks on Economic Indicators of Tenebrio molitor

[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.

Adsorption Performance of Activated Carbon Prepared from Corn Stalks

[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.

Effects of Corn Stalk-composted Organic Fertilizer on Physiochemical Properties of Tobacco-growing Soil

In order to explore the method of returning corn stalk into field, the effects of returning corn stalk direcfly into soil and applying corn stalk-composted orgar^c fertilizer into soil on the physiochemical properties of tobacco-growing soil were studied. The results showed that returning corn stalk into soil could reduce soil bulk density and increase soil porosity, so as to improve the water and fertilizer retention capacity of tobacco-growing soil. At the same time, returning corn stalk into soil could also increase the organic matter, available phosphorus and available potassi- um contents in tobacco-growing soil. In the early field growth stage of tobacco, soil alkali-hydrolyzable nitrogen content decreased slightly; but in the middle and later field growth stage, the alkali-hydrolyzable nitrogen content in tobacco-growing soil increased. The treatment effect of corn stalk＋urea＋fermentation bacteria and corn stalk＋urea＋BM was better than that of the control （returning corn stalk directly into soil）, indicating that the corn stalk-composted organic fertilizer had certain popular- ization value.

Degradation of corn stalk by the composite microbial system of MC1

The composite microbial system of MC1 was used to degrade corn stalk in order to determine properties of the degraded products as well as bacterial composition of MC1. Results indicated that the pH of the fermentation broth was typical of lignocellulose degradation by MC1, decreasing in the early phase and increasing in later stages of the degradation. The microbial biomass peaked on the day 3 after degradation. The MC1 efficiently degraded the corn stalk by nearly 70% during which its cellulose content decreased by 71.2%, hemicellulose by 76.5% and lignin by 24.6%. The content of water-soluble carbohydrates （WSC） in the fermentation broth increased progressively during the first three days, and decreased thereafter, suggesting an accumulation of WSC in the early phase of the degradation process. Total levels of various volatile products peaked in the third day after degradation, and 7 types of volatile products were detected in the fermentation broth. These were ethanol, acetic acid, 1,2-ethanediol, propanoic acid, butanoic acid, 3- methyl-butanoic acid and glycerine. Six major compounds were quantitatively analysed and the contents of each compound were ethanol （0.584 g/L）, acetic acid （0.735 g/L）, 1,2-ethanediol （0.772 g/L）, propanoic acid （0.026 g/L）, butanoic acid （0.018 g/L） and glycerine （4.203 g/L）. Characterization of bacterial cells collected from the culture solution, based on 16S rDNA PCR-DGGE analysis of DNAs, showed that the composition of bacterial community in MC1 coincided basically with observations from previous studies. This indicated that the structure of MC1 is very stable during degradation of different lignocellulose materials.

Effects of Different Pretreatment Modes on the Enzymatic Digestibility of Corn Leaf and Corn Stalk

Corn leaf and corn stalk were pretreated with only hot water and 0.1% sulfuric acid at 160℃ or 200℃, respectively. For hot water pretreatment, the pH of corn stalk hydrolysate decreased more rapidly than that of corn leaf as the reaction time increased. On the contrary, the pH of corn leaf hydrolysate increased more than that of corn stalk with diluted acid addition. Increasing temperature enhanced the xylose dissolution rate and increased cellulose digestibility. Compared with hot water, 0.1% sulfuric acid addition improved the xylan removal and the enzymatic hydrolysis of both corn leaf and corn stalk residue. Much less xylan must be removed to achieve the same cellulose digestibility for the corn leaf as that for the corn stalk; 55% digestibility was obtained when only 32% xylan was removed from corn leaf, whereas corn stalk required removal of about 50% of the xylan to achieve the same di- gestibility. Overall, the descending order of enzymatic digestibility was: dilute acid hydrolysate of corn leaf > dilute acid hydrolysate of corn stalk > water-only hydrolysate of corn leaf > water-only hydrolysate of corn stalk. Finally, one separate pretreatment strategy was developed to transfer corn leaf and corn stalk to fermentable sugars for fur- ther bioenergy production.

Preparation of active carbons from corn stalk for butanol vapor adsorption

Active carbons(ACs) were prepared through chemical activation of biochar from whole corn stalk(WCS)and corn stalk pith(CSP) at varying temperatures using potassium hydroxide as the activating agent. ACs were characterized via pore structural analysis and scanning electron microscopy(SEM). These adsorbents were then assessed for their adsorption capacity for butanol vapor. It was found that WCS activated at900 °C for 1 h(WCS-900) had optimal butanol adsorption characteristics. The BET surface area and total pore volume of the WCS-900 were 2330 m2/g and 1.29 cm3/g, respectively. The dynamic adsorption capacity of butanol vapor was 410.0 mg/g, a 185.1% increase compared to charcoal-based commercial AC(143.8 mg/g).

Effects of Different Nitrogen Sources and Metal Ions on Biogas Generation by Corn Stalk Fermentation

[Objective] The present study was conducted to explore the effects of dif- ferent nitrogen sources and metal ions on the biogas production process and biogas yield by fermentation of corn stalk powder using self-designed anaerobic fermenta- tion system. [Method] The biogas produced during fermentation was collected by water displacement, and measured by ignition. [Result] Ammonium bicarbonate, urea and yeast extract powder all increased biogas yield. Among them, ammonium bi- carbonate was the best nitrogen source. Ammonium dihydrogen phosphate showed an inhibitory effect on biogas production. Biogas yield was significantly increased by adding NaCl, KCl, MgCl2 or CaCl2, among which, NaCl had the best effect. [Conclu- sion] It is not conducive to the growth and development of methanogenic flora in the production of biogas using corn stalks as the only material in fermentation. The biogas yield can be increased by adding exogenous nitrogen, which reduces the carbon to nitrogen （C：N） ratio of fermentation materials. The biogas yield can be significantly increased by adding appropriate types and amount of electrolytes, with appropriate C：N ratio. The methanogenic flora is more tolerant to NaCl and KCl than to MgCl2 and CaCl2. Moreover, NaCl can not only significantly increase the biogas production, but also shorten startup period of methanogenic flora, thereby shortening the gas producing cycle.

A facile ionic liquid approach to prepare cellulose fiber with good mechanical properties directly from corn stalks

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.

Feed Production for Tenebrio molitor L. by Fermentation of Corn Stalks

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.

Pretreatment of Corn Stalk by Steam Explosion

A steam explosion pretreatment, which is one of the best ways of pretreating plant stalk, is applied at various severities to corn stalk. It could effectively modify the super-molecular structure of corn stalk and defibrating corn stalk into individual components. The relationship between yield of reducing sugar and the operating conditions, including temperature, pressure of steam explosion pretreatment and acidity, is also established. Experimental results prove that the steam explosion substantially increases the yield of reducing sugar, and the optimal condition for steam explosion is as follows: the pressure is 2.0 MPa, the pressure-retaining time 300 s, the initial acid concentration 1% and the acid treatment time 24 h.

Resistance Analysis of 25 Corn Varieties to Stalk Rot and Evaluation of Yield Loss

Due to the meteorological factors, Henan Province had a large-scale outbreak of corn stalk rot in 2014, and the incidence status of 25 varieties was investigated. According to the relevant resistance identification standards, Xundan.509 was classified as resistance variety; Yudan606, Jinsai38 and Xundan3136 were classified as moderate resistance ones, while the other 21 varieties were highly susceptible varieties. Using the yield loss rate of 5% as the critical value of disease tolerance standard, XundanS09, Yudan606, Jinsai38, Xundan3136, Huaiyu5288, QiaoyuS, XY046, Zhengyu10, Lile66, WeikeT02 and Xundan29 were classified into tolerance varieties of corn stalk rot. The concept between disease resistance and disease tolerance was distinguished. The diseased plant rate was used as the classification basis of disease resistance and the yield loss rate was used as the evaluation standard of disease tolerance. The relationship between both was showed by a Venn diagram.

Effects of Different Pretreatment Modes on the Enzymatic Digestibility of Corn Leaf and Corn Stalk

Corn leaf and corn stalk were pretreated with only hot water and 0.1% sulfuric acid at 160℃ or 200℃, respectively. For hot water pretreatment, the pH of corn stalk hydrolysate decreased more rapidly than that of corn leaf as the reaction time increased. On the contrary, the pH of corn leaf hydrolysate increased more than that of corn stalk with diluted acid addition. Increasing temperature enhanced the xylose dissolution rate and increased cellulose digestibility. Compared with hot water, 0.1% sulfuric acid addition improved the xylan removal and the enzymatic hydrolysis of both corn leaf and corn stalk residue. Much less xylan must be removed to achieve the same cellulose digestibility for the corn leaf as that for the corn stalk; 55% digestibility was obtained when only 32% xylan was removed from corn leaf, whereas corn stalk required removal of about 50% of the xylan to achieve the same di- gestibility. Overall, the descending order of enzymatic digestibility was: dilute acid hydrolysate of corn leaf > dilute acid hydrolysate of corn stalk > water-only hydrolysate of corn leaf > water-only hydrolysate of corn stalk. Finally, one separate pretreatment strategy was developed to transfer corn leaf and corn stalk to fermentable sugars for fur- ther bioenergy production.

Study on Humic Acids of the Soil Applied with Corn Stalk by Spectroscopy Measurements

Spectroscopy measurements （Fourier transform infrared differential spectroscopy, Carbon-13 nuclear magnetic resonance spectrometry, Matrix-assisted laser resorption/ionization-time of flight mass spectrometry） were performed to study the humic acids of the soil applied with corn stalk. The results showed that after incorporation of corn stalks into the soil, the soil humic acid （HA） changed significantly in different stages. During first 60 days, new HAs were formed by polymerization and seems to be similar to that of initial HAs from composting corn stalk, some little molecular organic matters also reacted with soil HAs and turned into parts of soil HAs. After 60 days of the corn stalk residue incorporation, new HAs were formed by polymerization of decomposed lignin molecules, some methylenes transformed into methyls and methoxyls since the 90th day. Application of corn stalk led to the increase of aliphatic components in soil HAs, the decrease in aromatic components of soil HAs and the suppression in oxidation degree of soil HAs. The average molecular weight of soil HAs also declined because of application of corn stalk.

A Constitutive Model for Uni-axial Compaction of Non-adhesive CornStalk Powder

In order to study mechanical behaviors of corn stalk powder during the compaction, the yield criterion for corn stalk powder is proposed with a plasticity theory. From the stress-strain curves of uni-axial compaction test for corn stalk powder, the constitutive model, in which the equations are modified by experiments on corn stalk powder, is adopted to describe plastic behaviors of powder, and is discussed based on the incremental theory and deformation theory. The numerical results agree well with the experimental ones.

Technical Parameter Optimization for Straw Fibre Mulching Film Raw Material from Corn Stalk

To obtain high quality raw materials,the optimization of process parameters of corn stalk-based raw material for straw fibre mulching film was studied.A central composite design(CCD)methodology of four factors and five levels was applied to determine the effects of four process variables,i.e.,stalk size,soaking time,working temperature and processing speed;the fibre yield,initial beating degree and fibre aspect ratio were selected as the objective functions.Fibre yield higher than 95%,initial beating degree greater than 9°SR and fibre aspect ratio greater than 45 were established as the expected values meeting the technical requirements of manufacturing stalk fibre mulching film.Response surface analysis methodology was employed.As a result,the optimal ranges of process variables were obtained as the following:the stalk size was from 3 cm to 10 cm,the soaking time was 18 h,the working temperature was 80℃,and the processing speed was 107-117 r·min^-1.The results could be applied to the design and optimization of the D200 type stalk fibre preparation machine and to the process of making raw materials of corn stalk-based straw fibre mulching film.

A Study of Adsorption of Modified Corn Stalk on PCP

The comprehensive utilization of corn stalks is an urgent agricultural and environmental problem to be solved in China.In this test,we use corn stalk as adsorbent for adsorption of PCP in water,and compare the impact of three modification methods(alkali treatment,pyrolysis,graft copolymerization) on corn stalk adsorption properties.Results show that the modified corn stalk's adsorption of PCP is increased from 5.4 mg/g to 13.9 mg/g,17.8 mg/g and 22.5 mg/g,respectively; the corn stalk after graft copolymerization and modification has the greatest adsorption capacity; after modification,both the adsorption capacity and adsorption rate constant of corn stalk on PCP are increased significantly.

Interfacial Modification of Corn Stalk Cellulose Reinforced Used Rubber Powder Composites Treated with Coupling Agent

Corn stalk cellulose(CS)/used rubber powder(RP)composites were prepared by mixing,the silane coupling agent 3-Mercaptopropyl trimethoxysilane(KH590),r-Aminopropyltrieth oxysilane(KH550),isopropyl dioleic(dioctylphosphate)titanate(HY101)and bis-(γ-triethoxysilylpropyl)-tetrasulfide(Si69)were used to modify the interface of composites.The effects of the CS and coupling agents on the mechanical properties,thermal properties,interfacial morphology and structure of the composites were investigated,respectively.The results showed that the addition of CS could effectively improve the mechanical properties of the composites.Compared with the untreated composites,the interfacial bonding between CS and RP was significantly improved by the coupling modification treatment,and the tensile strength and elongation at break of composites with Si69 increased by 3.13 MPa and 10%,respectively,the Si69 showed the best coupling modification effect,followed by KH590,then KH550 and HY101 when the CS content was 25 pph(part per hundred)and coupling agent 1.5 pph,and the thermal decomposition temperature increased by 30℃.