草料自燃防范的研究

近年来兴起的秸秆打包并不能消除其自燃的危险。使用弗-卡模型,测定了不同体积稻麦秸秆的临界温度(Ta,cr);并依据实际状况对弗-卡模型进行了改进,测定了稻麦秸秆的Tc;探讨了含水量以及打包密度对Tc的影响。得出初始含水量13.65%,密度344kg.m-3打包麦秸秆的Tc为66～69℃,最大安全堆砌直径为7.3m;初始含水量15.27%,密度285kg.m-3打包稻秸秆的Tc为83～86℃,最大安全堆砌直径为8.5m的结论。这一研究对草料场的安全管理意义重大。     

Rice straw paper incorporated with activated carbon as an ethylene scavenger in a paper‐making process

Rice straw contains cellulose as its main carbohydrate component, which is the major constituent for making rice straw paper as an alternative use of the residue. The objectives of this study were to determine a rice straw paper‐making process incorporating activated carbon (AC) and the effect of AC and the glucomannan (GLU) content on the physical and mechanical properties, including the ethylene adsorption capacity of rice straw paper containing AC. The results showed that AC was an effective ethylene scavenger, and it was possible to incorporate it into the rice straw paper‐making process. Increasing the AC content increased the ethylene adsorption capacity but decreased the strength of the AC‐rice straw paper. GLU maintained the strength of the rice straw paper but did not affect the ethylene adsorption capacity. Incorporation of 30% AC content with 0.3% GLU in the AC‐rice straw paper produced the maximum level of ethylene scavenging (77%). Moreover, AC‐rice straw paper is an environmentally friendly material owing to its reusability, and it has the potential for applications in food and agricultural packaging because it can act as an ethylene scavenger and also provide protection against mechanical damage.     

秸秆固化技术现状及发展趋势分析

从开发利用秸秆固化成型燃料的意义入手,结合国内外应用生物质固化成型技术的现状,分析了当前技术的主要原理及存在的问题,进而提出了技术发展的主要方向及相关两项具有发展潜力的新技术,为今后秸秆固化成型产业的发展提供建议。     

Air analysis in the assessment of fumonisin contamination risk in maize

BACKGROUND: In maize‐growing areas where fumonisin contamination is endemic, there is an urgent need for novel methods to assess the quality of grain lots before their delivery to common drying and storage collection centres. Aerobiological samples of fungal spores released during harvest were analysed to establish a relationship between fumonisin contamination and the abundance of pathogen propagules collected in the combine harvester using a cyclone and membrane filters. Filter‐captured propagules were analysed by direct plating, immunoenzymatic assay of specific Fusarium extracellular polysaccharides and real time polymerase chain reaction of the extracted DNA using fum1, a gene involved in the biosynthesis of fumonisin, as a target. RESULTS: The results showed that time of harvest and environmental conditions strongly influenced the efficiency and performance of the collection system. The data obtained were informative in comparing individual samples collected under similar conditions. The immunoenzymatic assay provided the most reliable data, which improved the ability of a neural network to predict the fumonisin content of lots, when added to agronomic, environmental and phytosanitary data. CONCLUSION: This is the first attempt to evaluate the Fusarium propagules dispersed during harvesting as a predictive means to assess maize quality. A method based on cyclone/filter capture and immunological detection has been shown to be feasible and to have the potential for the development of a continuous monitoring system, but the prediction capabilities in the present implementation were limited. Copyright © 2010 Society of Chemical Industry     

The impact of barley straw conditioning on the inhibition of Scenedesmus using chemostats

The current paper investigates the role of barley straw conditioning on inhibiting the alga Scenedesmus. Fresh, pre-rotted and white rot fungi (WRF) augmented straw was tested in a series of chemostat experiments over 15 weeks. All three systems were effective at inhibiting the alga with differences observed in the lag time before inhibition occurred and the rate of alga decline. Lag times of 8, 4 and 1 week(s) were recorded for the fresh, rotted and fungi-treated straws, respectively, with a maximum inhibition rate of >7 × 10⁴ cells week⁻¹ observed for the fungi pre-treated system. Overall, the results indicate that pre-treatment is a viable method to enable barley straw to be used in a more reactive manner. Explanation is postulated that during pre-treatment no alternative sources of nitrogen are available, thereby leading to greater bacterial decomposition of straw lignin to release inhibitory substances. The principle of utilising an engineered pre-treatment by inoculating barley straw with WRF to enhance the impact of the straw on algal inhibition has been clearly demonstrated. Further work is required to understand how the straw pre-treatment stage can be reduced to minimise its duration while maximising the inhibitory effect of adding barley straw.     

玉米乙二醇合成PET的研究

以玉米为原材料生产的乙二醇合成PET并进行固相缩聚,对其生产过程及其结果进行分析和讨论。     

Moisture Dependent Physical Properties of Dry Sweet Corn Kernels

Physical properties of sweet corn kernels have been evaluated as a function of kernel moisture content, varying from 9.12 to 17.06% (db). In the moisture range, kernel length, width, thickness, and geometric mean diameter increased linearly from 9.87 to11.09 mm, 7.41 to 9.25 mm, 3.25 to 4.37 mm, and 6.18 to 7.62 mm, respectively, with increase in moisture content from 9.12–17.06%. The sphericity index, kernel volume, kernel surface area, and thousand seed weight increased linearly from 62.6 to 68.8, 93.8 to 194.3 mm³, 120.1 to 182.9 mm², and 220 to 268 gr, respectively. Apparent density and bulk density decreased linearly from 1.315 to 1.232 g/cm³ and 0.765 to 0.698 g/cm³, respectively, while bulk porosity increased from 41.8 to 43.3%. The highest static coefficient of friction was found on the plywood surface. The static coefficient of friction increased from 0.680 to 0.891, 0.605 to 0.741, and 0.530 to 0.644 for plywood, galvanized iron, and aluminum surfaces, respectively. The angle of repose increased linearly from 30.2 to 35.2° with the increase of moisture content.     

稻草末固定白腐真菌用于染料废水处理的研究

微电解－白腐菌生物降解－絮凝沉降联合处理系统对活性染料生产废水的处理效果明显，CODCr 去除率达90％以上，色度由12800降到80，出水清亮，达到排放标准。     

Modeling calcium and water intake in threshed corn grain during thermo-alkaline treatment

A mathematical model describing simultaneous solvent diffusion and gelatinization of starch was used to explain the water and calcium absorption in threshed corn grains during the thermo-alkaline treatment. A computer-aided nonlinear optimization technique was used to find the effective diffusion coefficients and the reaction rate constants of water and calcium in threshed corn grains at boiling temperature (92.5 ± 0.3 °C). The mathematical model shows good correlation between measured and predicted values of water and calcium intake. It is concluded that the cooking process is limited by the reaction of starch components with water and calcium. The effective diffusion coefficient for water varied between 1.18 × 10⁻¹⁰ and 1.45 × 10⁻¹⁰ m²/s and for calcium between 8.55 × 10⁻¹⁰and 16.77 × 10⁻¹⁰ m²/s. The diffusion of water and calcium in threshed corn was produced with a reaction rate constants in the range of 6.83 × 10⁻⁴ to 10.4 × 10⁻⁴ s⁻¹ for water and 2.7 × 10⁻⁵–7.6 × 10⁻⁵ s⁻¹ for calcium. According to these effective diffusion coefficient values the diffusive process seems to be slower for water than for calcium. However, the reaction rate constant values are approximately 10 times higher for water than for calcium which may indicate that a higher amount of solvent was linked in the water diffusion process due to the gelatinization. Low concentration of Ca(OH)₂ such as 0.10% did not significantly affect the water diffusion of threshed corn during the cooking process.     

Evaluation of a hydrothermal process for pretreatment of wheat straw—effect of particle size and process conditions

BACKGROUND: Hydrothermal processes are an eco‐friendly processes that provide an interesting alternative for chemical utilization of lignocellulosic materials, in which water and crop residues are the only reagents. In this work the effect of process conditions (size distribution of the wheat straw, temperature and time) was evaluated against production of fermentable products. RESULTS: The use of milled wheat straw fractions as a raw material containing blends of different particle size distribution showed that the latter had an influence on the final sugars in the hydrolysate. Improved values of glucose (21.1%) and xylose yields (49.32%) present in the hydrolysate were obtained with treatment severity factors of 2.77 and 3.36, respectively. Mathematical models were developed aimed at establishing the effect of process conditions on monosaccharide concentration and its degradation in the liquor. CONCLUSION: This work shows that the use of wheat straw blends with various particle sizes has a significant effect on the extraction of fermentable products. The effect of treatment severity, which takes into account both processing time and temperature was also evaluated. These results are of importance for process design. Copyright © 2010 Society of Chemical Industry