Methodology for estimating removable quantities of agricultural residues for bioenergy and bioproduct use

A methodology was developed to estimate quantities of crop residues that can be removed while maintaining rain or wind erosion at less than or equal to the tolerable soil-loss level. Six corn and wheat rotations in the 10 largest corn-producing states were analyzed. Residue removal rates for each rotation were evaluated for conventional, mulch/reduced, and no-till field operations. The analyses indicated that potential removable maximum quantities range from nearly 5.5 million dry metric t/yr for a continuous corn rotation using conventional till in Kansas to more than 97 million dry metric t/yr for a corn-wheat rotation using no-till in Illinois.     

Hydrolysis characteristics of tissue fractions resulting from mechanical separation of corn stover

Corn stover has potential as a resource for both fiber and chemical needs if separation strategies can be developed to deal with its heterogeneity. Relative hydrolysis characteristics were assessed for pith (sclerenchyma and parenchyma) and fiber (collenchyma) tissue fractions derived from mechanical separation of corn stover to determine whether classification by tissue type resulted in fractions with different hydrolysis response. The physical characteristics of the tissue fractions were analyzed. The hydrolysis behavior of the fractions was evaluated under both acidic and basic conditions. The results from the hydrolysis experiments are compared with previously reported compositional analysis for the tissue fractions.     

Hydrodynamic separation of grain and stover components in corn silage

Mixing fresh silage in water resulted in partial segregation of grain from stover. Grain concentration was 75% in the sunk material when silage was relatively dry (64% moisture content [MC]) and 41% when silage was relatively wet (74% MC). Partial drying to remove 20 percentage units of moisture prior to water separation increased grain concentration to 92%, and complete drying increased grain concentration to 99%. Sieving without drying followed by water separation resulted in a grain concentration of 79%. A byproduct of water separation is a large amount of soluble and deposited fine particles in the effluent: 18% of original dry matter after one separation, and between 21 and 26% after eight separations. In an industrial setting, hydrodynamic separation of silage with minimal pretreatment could provide a feedstock with a high concentration of grain (75–80%). In a laboratory setting, hydrodynamic separation with prior oven drying could provide a method to separate grain from stover in corn silage by reaching a grain concentration higher than 99%. Contribution number 761, Soils and Crops Research and Development Centre, AAFC.     

Effect of corn stover concentration on rheological characteristics

Corn stover, a well-known example of lignocellulosic biomass, is a potential renewable feed for bioethanol production. Dilute sulfuric acid pretreatment removes hemicellulose and makes the cellulose more susceptible to bacterial digestion. The rheologic properties of corn stover pretreated in such a manner were studied. The Power Law parameters were sensitive to corn stover suspension concentration becoming more non-Newtonian with slope n, ranging from 0.92 to 0.05 between 5 and 30% solids. The Casson and the Power Law models described the experimental data with correlation coefficients ranging from 0.90 to 0.99 and 0.85 to 0.99, respectively. The yield stress predicted by direct data extrapolation and by the Herschel-Bulkley model was similar for each concentration of corn stover tested.     

Multi-dimensional chromatography using on-line coupled microcolumn liquid chromatography—capillary gas chromatography for quantitative pesticide residue analysis

Highly selective separations can be achieved by utilizing different separation modes in a multi-dimensional (on-line coupled) chromatographic system. The application of such a system utilizing microcolumn liquid chromatography coupled on-line to capillary gas chromatography for the determination of 2-(1,1-dimethylethyl)-5-pyrimidinol, a pesticide metabolite, in various corn matrices at the ng g^?1 level is described. A comparative quantitative study with conventional manual sample pretreatments followed by capillary gas chromatography-mass spectrometry indicated equivalence between the two techniques. The system offers the advantages of reduced sample handling steps and analysis time, high potential for automation and adequate sensitivity.     

玉米秸秆催化液化制备生物油实验研究

以玉米秸秆为原料,添加分子筛催化剂在体积为500 mL的高温高压反应釜中进行催化液化制备生物油实验研究。选取反应温度、催化剂含量和反应时间三个主要因素为变量,探究其对玉米秸秆催化液化产物分布的影响。利用气相色谱-质谱联用仪(GC-MS)和傅里叶红外光谱仪(FT-IR)对玉米秸秆生物油的成分和官能团结构进行分析。结果表明,玉米秸秆的最佳催化液化条件为,反应温度为340 ℃,玉米秸秆15 g,FeHZSM-5催化剂含量为6.67%,反应时间为30 min。在此条件下,生物油产率为28.03%,催化液化整体转化率为81.73%。生物油的主要成分为酚类和长链酯类,生物油的热值达30.08 MJ/kg。     

LC and SPE Determination of Chlorophacinone in Corn Grains, Soil and Rat Plasma

A liquid chromatographic method was used for the analysis of chlorophacinone in corn, soil and rat plasma. Sample preparation differed from corn, soil and serum. Simple liquid extraction procedures were applied to soil and corn; solid phase extraction using Oasis HLB cartridges and easy protocol was used for plasma. Liquid chromatography was on X-terra C18 column. The mobile phase used did not contain ion-pairing reagent, it was constituted with methanol/ammonium bicarbonate (0.01 M, pH = 7), 70/30, v/v at 1 mL min⁻¹. UV detection was by using photodiode detector operating at 282 nm. Complete validation of the proposed procedure for corn, soil and serum was made.     

Increasing the Value of Hominy Feed as a Coproduct by Fermentation

Hominy feed is a low value ($83.7/metric ton) coproduct of the corn dry milling process that accounts for nearly 35% of the starting corn quantity. The average composition of hominy feed on a dry basis is 56.9% starch, 25.2% neutral detergent fiber, 11.1% protein, and 5.3% fat. Starch in hominy feed can be fermented to ethanol thus increasing its levels of protein and fat. The increase in protein and fat percentages may increase the market competitiveness and price of hominy feed. Hydrolysis and fermentation were performed on nine hominy feed samples collected from three corn dry milling plants in the USA. The original hominy feed samples and postfermentation solids were analyzed for starch, protein, fat, and fiber content. Compared to the original hominy feed, the percentage increase in protein, fat and fiber in postfermentation solids of nine samples ranged from 10.4 to 21.3, 6.78 to 10.6, and 12.6 to 28.7% (dry basis), respectively. Ethanol yields varied from 271.7 to 380.2 l/metric ton for the nine hominy feed samples. These results indicate that the value of hominy feed as an animal feedstock can potentially be increased with fermentation and can produce more profit per metric ton than currently being derived by its sale as a low protein feed ingredient.     

巯基棉分离富集-FAAS法测定爆玉米花中痕量铅

本文借助巯基棉分离富集技术,以火焰原子吸收光谱法（ＦＡＡＳ）测定爆玉米花中痕量铅。该方法采用巯基棉做分离富集剂,简便易行,并能有效的消除共存元素的干扰,回收率为９７．５％－１０６．０％。     

维药玉米须的微量元素分析

用原子吸收分光光度法测定维药玉米须中的K,Na, Ca, Fe, Cu, Co, Ni, Zn, Mn, Mg, Cr等11种微量元素。结果表明：玉米须含有丰富的人体必需的微量元素,其中K,Co, Zn, Cu, Fe的含量更显著。探讨了微量元素与玉米须的药效关系,通过本实验为玉米须的进一步研究和综合开发利用提供了新的科学依据。