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排序方式: 共有164条查询结果,搜索用时 31 毫秒
131.
132.
Mohsen Taherdanak Hamid Zilouei Keikhosro Karimi 《International Journal of Green Energy》2016,13(11):1129-1134
Dilute sulfuric acid pretreatment was used to improve the biomethane production from wheat plant (WP) via mesophilic anaerobic digestion. The pretreatments were performed at 121°C for different time durations of 10, 30, 60, and 120 min. The maximum methane yield of 302.4 mL/g volatile solids (VS) was obtained after the pretreatment for 120 min, which was 15.5% higher than that of the untreated WP. The highest amounts of lignin removal (15.2%) and xylan degradation (91.5%) were also achieved after this pretreatment. The pretreatment for 60 min enhanced the methane yield by 8.9%, while the pretreatments for 10 and 30 min had no positive effects on the methane yield. All of the pretreatments significantly removed the hemicelluloses. Moreover, the qualitative analysis of the untreated and pretreated WP structure showed significant reduction in the crystallinity index accompanied by the destruction of surface layers of WP structure after pretreatment. 相似文献
133.
T. Kikas M. Tutt M. Raud M. Alaru R. Lauk J. Olt 《International Journal of Green Energy》2016,13(1):49-54
This paper investigates the suitability of Jerusalem artichoke (Helianthus tuberosus L.), fiber hemp (Cannabis sativa L.), energy sunflower (Helianthus annuus L.), Amur silver-grass (Miscanthus sacchariflorus), and energy grass cultivar (cv) Szarvasi-1 for biofuel production in Northern climatic conditions. Above ground biomass, bioethanol production yield, and methane production yield are used as indicators to assess the bio-energy potential of the culture. Results presented show that energy crops of Southern origin produce 30–70% less biomass than in the origin region. Nonetheless, both perennial and annual energy crops produce high above ground biomass yields (660–1280 g m–2) for Northern climatic conditions. Experimental results show that bioethanol yield is dependent on cellulose content of the biomass. The higher the cellulose content, the higher the bioethanol yield. The biogas production on the other hand, depends on lignin content. The lower the lignin content the higher the biogas yield. Therefore, the selection of the energy crop for bioethanol production should be based on high cellulose content, while for biogas production it should rather be based on the low lignin content. 相似文献
134.
Jitendra Kumar Keyath Nisar N. A. Shakil Suresh Walia Rajender Parsad 《Journal of environmental science and health. Part. B》2013,48(4):330-335
Controlled release (CR) formulations of metribuzin in Polyvinyl chloride [(PVC) (emulsion)], carboxy methyl cellulose (CMC), and carboxy methyl cellulose-kaolinite composite (CMC-KAO), are reported. Kinetics of its release in water and soil was studied in comparison with the commercial formulation (75 DF). Metribuzin from the commercial formulation became non-detectable after 35 days whereas it attained maxima between 35–49 days and became non-detectable after 63 days in the developed products. Amongst the CR formulations, the release in both water and soil was the fastest in CMC and slowest in PVC. The CMC-KAO composite reduced the rate of release as compared to CMC alone. The diffusion exponent (n value) of metribuzin in water and soil ranged from 0.515 to 0.745 and 0.662 to 1.296, respectively in the various formulations. The release was diffusion controlled with half release time (t1/2) from different controlled release matrices of 12.98 to 47.63 days in water and 16.90 to 51.79 days in soil. It was 3.25 and 4.66 days, respectively in the commercial formulation. The period of optimum availability of metribuzin in water and soil from controlled released formulations ranged from 15.09 to 31.68 and 17.99 to 34.72 days as against 5.03 and 8.80 days in the commercial formulation. 相似文献
135.
冻干壳聚糖微球固定化纤维素酶的研究 总被引:2,自引:0,他引:2
分别以冻干壳聚糖微球和湿壳聚糖微球为载体,戊二醛为交联剂进行纤维素酶的固定化研究,并对2种固定化酶的热稳定性、米氏常数、重复利用次数、pH值加以对比分析。确定酶固定化的适宜条件为:0.03g冻干壳聚糖微球与10mL4g/L戊二醛交联4h后,加入10mg酶固定2h,酶活力回收率为96.3%;0.1g湿壳聚糖微球与10mL 2g/L戊二醛交联2h后,加入6mg酶固定4h,酶活力回收率为62.4%。与游离酶相比,2种固定化酶的米氏常数均降低;具有很好的热稳定性;最适酶解温度分别为60℃,50℃;酶解反应适宜pH范围3.0—4.0,最适pH值均向酸性方向移动。冻干载体更易与酶分子结合,酶活力回收率高于湿载体固定化酶。 相似文献
136.
137.
E. L. Vorobeichik 《Russian Journal of Ecology》2007,38(6):398-407
Spatial variation in the cellulolytic activity of the soil microflora during the growing season (from May to September) has been studied in spruce-fir forests exposed to emissions from the Middle Ural Copper-Smelting Plant. It has been shown that the average rate of decomposition of pure cellulose in polluted areas is significantly reduced, with its spatial variation being markedly increased. The spatial pattern of cellulolytic activity remains stable during the growing season, and the integrated parameters of frequency distributions in zones with different pollution levels change with time in the same direction. 相似文献
138.
湿地生态系统是极其敏感的,与环境变化紧密相关。湿地沉积物同位素在近年来的古环境恢复研究中被广泛应用,已趋向成熟,但传统的同位素载体存在一些问题难以摒除,使得运用该方法进行古环境还原经常出现偏差与不确定因素。近15年来,一种同位素研究的新载体被广泛应用-沉积物纤维素,与其他载体相比,植物纤维素具有良好的稳定性,记录了最原始的环境信息。目前,该方法的理论研究日趋成熟,并且它的提取方法近年来也得到了不断改良,实验仪器的改进也使该测量数据更加简便易行,许多学者用沉积物种提取的纤维素同位素对当地古环境与古水文学状况进行了还原,并且其他证据相吻合,证明了此方法的可靠性。但是,该方法还需要在技术手段、理论研究上进一步加深。 相似文献
139.
140.
N. I. Andreyashkina 《Russian Journal of Ecology》2008,39(7):490-494
A relatively high biological activity of soils has been revealed at the upper timberline in the Polar Urals. The role of the
altitudinal gradient as a factor of destruction process has distinctly manifested itself upon comparing decomposition rates
of flowering plant foliage and herbaceous plant roots in the forest and in the tundra. The qualitative composition of decomposing
plant matter has also proved to play a significant role. The soil moisture regime of the ecotope is the leading factor of
the destruction process. 相似文献