Valorisation of waste fractions from autohydrolysis of selected lignocellulosic materials

Non‐isothermal processing of lignocellulosic materials in aqueous media (autohydrolysis reaction) under mild conditions leads to solutions containing valuable chemicals (oligosaccharides, sugars and acetic acid) and other, undesired, compounds (belonging to the extractive and acid‐soluble lignin fractions) which have to be removed in further purification treatments. Liquors obtained by non‐isothermal autohydrolysis of Eucalyptus globulus wood and corncobs under a variety of operational conditions were extracted with ethyl acetate in order to remove non‐saccharide components, and the suitability of the fraction dissolved in the organic phase was assayed for possible utilisation as an antioxidant. The yield and antioxidant activity of ethyl acetate extracts (measured by the α,α‐diphenyl‐β‐picrylhydrazyl (DPPH) radical scavenging capacity) showed a strong dependence on the autohydrolysis conditions. The antioxidant activity of extracts obtained under selected operational conditions compared well with synthetic antioxidants. © 2003 Society of Chemical Industry     

Behavioral Changes in Workers of the Leaf-Cutting Ant Atta sexdens rubropilosa Induced by Chemical Components of Eucalyptus maculata Leaves

The response of Atta sexdens rubropilosa Forel workers to essential oils, epicuticular wax and hexane, dichloromethane, ethyl acetate, and methanol extracts of Eucalyptus maculata was evaluated. Hexane extracts of E. maculata interfered with the recognition mechanism among workers. The main active compounds identified from this plant were the sesquiterpenes elemol and beta-eudesmol. These compounds may be responsible for the resistance of this species to ant attack.     

Inheritance Of Resistance To Mammalian Herbivores and Of Plant Defensive Chemistry In A <Emphasis Type="Italic">Eucalyptus</Emphasis> Species

Hybridization in plants provides an opportunity to investigate the patterns of inheritance of hybrid resistance to herbivores, and of the plant mechanisms conferring this resistance such as plant secondary metabolites. We investigated how inter-race differences in resistance of Eucalyptus globulus to a generalist mammalian herbivore, Trichosurus vulpecula, are inherited in their F₁ hybrids. We assessed browsing damage of three-year-old trees in a common environment field trial on four hybrid types of known progeny. The progency were artificial intra-race crosses and reciprocal inter-race F₁ hybrids of two geographically distinct populations (races) of E. globulus; north-eastern Tasmania and south-eastern Tasmania. Populations of trees from north-eastern Tasmania are relatively susceptible to browsing by T. vulpecula, while populations from south-eastern Tasmania are more resistant. We assessed the preferences of these trees in a series of paired feeding trials with captive animals to test the field trial results and also investigated the patterns of inheritance of plant secondary metabolites. Our results demonstrated that the phenotypic expression of resistance of the inter-race F₁ hybrids supported the additive pattern of inheritance, as these hybrids were intermediate in resistance compared to the pure parental hybrids. The expression of plant secondary metabolites in the F₁ hybrids varied among groups of individual compounds. The most common pattern supported was dominance towards one of the parental types. Together, condensed tannins and essential oils appeared to explain the observed patterns of resistance among the four hybrid types. While both chemical groups were inherited in a dominant manner in the inter-race F₁ hybrids, the direction of dominance was opposite. Their combined concentration, however, was inherited in an additive manner, consistent with the phenotypic differences in browsing.     

利用Eucalyptus和开源操作系统构建和实现私有云

使用私有云可以带来很大的便利和大大提高资源的使用率以及降低维护费用,如何快捷、低成本构建私有云成为最关键的问题,有许多针对构建私有云思路和设计,有的过于复杂、有的过于投入昂贵、有的维护繁琐.本文论述使用开源操作系统Ubuntu（服务器版）构建和实现一个Eucalyptus结构私有云,并通过该云提供IaaS服务.以这种构建方式能够快速实现私有云,具有成本低廉、维护简单、管理方便的特点.     

The combustion characteristics of high-heating-rate chars from untreated and torrefied biomass fuels

Torrefaction of biomass is of great interest at the present time, because of its potential to upgrade biomass into a fuel with improved properties. This study considers the fundamentals of combustion of two biomass woods: short rotation willow coppice and eucalyptus and their torrefied counterparts. Chars were prepared from the untreated and torrefied woods in a drop tube furnace at 1100 °C. Fuels and chars were characterised for proximate, ultimate and surface areas. Thermogravimetric analysis was used to derive pyrolysis and char combustion kinetics for the untreated and treated fuels and their chars. It was found that the untreated fuels devolatilise faster than their torrefied counterparts. Similarly, the chars from the untreated biomass were also found to be more reactive than chars from torrefied fuels, when comparing reaction rates. However, the activation energy value (Ea) for combustion of the untreated eucalyptus char was higher than that for the torrefied eucalyptus chars. Moreover, the eucalyptus chars were more reactive than the willow char analogues, although they had seen a lower extent of burn off, which is also a parameter indicative of reactivity. Similar trends in were also observed from their intrinsic reactivities; i.e. chars from the untreated fuel were more reactive than chars from the torrefied fuel and eucalyptus chars were more reactive than willow chars. Chars were also studied using scanning electron microscopy with energy-dispersive X-ray analysis. This latter method enabled a semi-quantitative analysis of char potassium contents, which led to an estimation of potassium partitioning during char formation and burnout. Results show a good correlation between potassium release and percent burnout. With respect to the effect of torrefaction on fuel-N, findings suggest that torrefaction would be beneficial for pf combustion in terms of nitrogen emissions, as it resulted in lower fuel-N contents and ∼72–92% of the fuel-nitrogen was released with the volatile fraction upon devolatilisation at 1100 °C.     

桉树叶片提取物的杀虫活性及应用初步研究

采用3种溶剂对桉树叶片进行加热回流提取,分别采用喷雾法和浸渍法测定提取物对鳞翅目害虫黏虫、半翅目害虫蚜虫及蜱螨目害虫朱砂叶螨生物活性。在初筛的基础上,对甲醇、丙酮和石油醚提取物进行了烟蚜复筛及温室盆栽试验。试验结果表明:各提取物对黏虫及朱砂叶螨在10000mg/L的浓度均未表现出杀虫活性,甲醇、丙酮和石油醚提取物对蚜虫均表现出一定的毒杀活性,对烟蚜的LC_(50)值分别为4 644.61、4 276.94、507.47 mg/L,其中石油醚提取物表现出了较高的生物活性。进行了进一步的温室盆栽验证试验,发现药后7 d,10000 mg/L的石油醚提取物对烟蚜的防效达到80.31%,有进一步研究的价值。     

Selecting the Pre-Hydrolysis Conditions for Eucalyptus Wood in A Fractional Exploitation Biorefining Scheme

The operating conditions for the autohydrolysis of eucalyptus wood were optimized with a view to maximizing hemicellulose extraction while preserving the integrity of glucan. The influence of the operating conditions used in the soda–anthraquinone pulping of the solid phase resulting from the autohydrolysis process was examined. Autohydrolysis of the raw material at a liquid/solid ratio of 8 kg water/kg material at 180°C for 30 min was found to provide a commercially useful liquid phase containing most of the starting hemicellulose. The autohydrolysis treatment allowed the subsequent production of soda–anthraquinone cellulose pulp and paper with properties as good as or even better than those obtained without the pretreatment.     

Thermal Analysis of Charcoal from Fast-Growing Eucalypt Wood: Influence of Raw Material Moisture Content

This study aimed to investigate the influence of raw material moisture content on the properties of charcoal from fast-growing Eucalyptus benthamii wood. For that, three treatments were performed with 0, 30, and 50% in relation to the wet basis moisture of the wood samples. The carbonization process used an electric kiln with a heating rate of 1.60°C min^?1, initial temperature of 25 to 600°C at the end, kept constant at that temperature for two hours. Variables were statistically analyzed for charcoal yield, non-condensable gases, liquor, and fixed carbon and properties: fixed carbon content, volatile, ash, bulk density, and moisture content of charcoal. According to the results, the charcoal produced from dry wood presented the highest properties, yet the charcoal produced from wood with 30% moisture content showed similar properties.     

桉树组织培养与再生系统建立研究

本实验通过组织培养手段,以MS、1/2MS、White为基本培养基,利用6-BAI、BA、NAA等生长调节物质进行不同浓度及比例的组合,对以桉树叶片为材料进行愈伤诱导及植株再生的组培再生系统进行了初步尝试,同时对桉树的外植体灭菌、增殖和生根进行了研究。获得了桉树增殖、生根诱导的适宜配养基和培养条件,初步建立了通过愈伤组织诱导芽器官发生的再生系统。研究发现,以桉树叶片为材料,在1/2MS 6-BA0.5mg/L IBA1.0mg/L或NAA0.5mg/L培养基上进行愈伤组织诱导,愈伤率在90%以上;以1/2MS 6-BA1.0mg/L NAA0.1mg/L培养基对形成的愈伤组织进行芽分化培养时,愈伤组织可发生不定芽。     

微电解法用于处理桉木CTMP废液

采用微电解法处理桉木CTMP废液,探讨了pH值、反应时间、曝气、温度和添加剂等对废水色度和CODCr去除率的影响,得到优化的处理工艺参数。结果表明,在常温搅动曝气、pH值为4、铁碳比(体积比)为1、60min和加入适量铜屑的条件下,废水的脱色率可达95%以上,CODCr去除率达75%以上。