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81.
采用自制木粉/壳聚糖接枝丙烯酸-丙烯酰胺吸附树脂R1、R2、R3对二元金属离子Cu2+/Pb2+和Zn2+/Pb2+溶液中的吸附性能进行了较系统考察。Pb2+离子溶液中存在竞争离子Cu2+、Zn2+时,随竞争离子浓度增加,3种吸附树脂R1、R2、R3对Pb2+的吸附量明显下降,而竞争离子吸附量显著增加。二元溶液中各金属离子浓度相同时,3种树脂对竞争离子Cu2+、Zn2+的吸附量大于对Pb2+的吸附量;各溶液中分别加入NaCl及NaNO3、尿素后,对Pb2+离子的吸附量下降迅速。随吸附树脂用量增加,竞争离子Cu2+、Zn2+的吸附量逐渐减小,Pb2+的吸附量在吸附树脂用量0.10 g/L(Zn2+/Pb2+溶液)或0.15 g/L(Cu2+/Pb2+溶液)时出现最大值。溶液pH值对树脂吸附性能有显著影响。3.0  相似文献   
82.
Often perceived as a Cinderella material, there is growing appreciation for solid waste as a renewable content thermal process feed. Nonetheless, research on solid waste gasification and sulphur mechanisms in particular is lacking. This paper presents results from two related experiments on a novel two stage gasification process, at demonstration scale, using a sulphur-enriched wood pellet feed.Notable SO2 and relatively low COS levels (before gas cleaning) were interesting features of the trials, and not normally expected under reducing gasification conditions. Analysis suggests that localised oxygen rich regions within the fluid bed played a role in SO2’s generation. The response of COS to sulphur in the feed was quite prompt, whereas SO2 was more delayed. It is proposed that the bed material sequestered sulphur from the feed, later aiding SO2 generation. The more reducing gas phase regions above the bed would have facilitated COS – hence its faster response. These results provide a useful insight, with further analysis on a suite of performed experiments underway, along with thermodynamic modelling.  相似文献   
83.
Earlier studies documented the loss of wood preservatives from new wood. The objective of this study was to evaluate losses from weathered treated wood under field conditions by collecting rainfall leachate from 5 different wood types, all with a surface area of 0.21 m2. Wood samples included weathered chromate copper arsenate (CCA) treated wood at low (2.7 kg/m3), medium (4.8 kg/m3) and high (35.4 kg/m3) retention levels, new alkaline copper quat (ACQ) treated wood (1.1 kg/m3 as CuO) and new untreated wood. Arsenic was found to leach at a higher rate (100 mg in 1 year for low retention) than chromium and copper (<40 mg) in all CCA-treated wood samples. Copper leached at the highest rate from the ACQ sample (670 mg). Overall results suggest that metals' leaching is a continuous process driven by rainfall, and that the mechanism of release from the wood matrix changes as wood weathers.  相似文献   
84.
介绍了模块式扁袋除尘器的工作原理及技术特点.通过某木工制造厂木工车间通风除尘工程应用实践,证明该除尘器能满足木工车间通风除尘、劳动保护和环境保护的需要,并能取得良好的治理效果.  相似文献   
85.
为研究相邻木结构建筑火灾由已燃建筑传递至未燃建筑的临界值,利用突变理论与数值模拟分别研究相同条件下贵州省典型木结构建筑火灾发展过程中发生突变现象的临界值,并采用实验手段对前2种方法所测得的结果进行验证,从而证明尖点突变理论在相邻木结构建筑火灾蔓延临界值预测中的可行性与有效性。建立描述相邻木结构建筑火灾发展过程的能量守恒方程,通过对能量守恒方程的推导,得到相邻木结构建筑火灾突变势函数。结果表明:在相邻木结构建筑火灾发展过程中,火焰由已燃建筑传递至未燃建筑这一过程具有尖点突变的特征,计算出的火灾蔓延临界值为892.2 K;根据数值模拟找到已燃建筑传递至未燃建筑的状态,此时的临界值为881.5 K:2组简易实验测得的临界温度分别为903.2,889.8 K,与突变理论预测值和数值模拟结果相比,3种方法误差不大,因此可认为利用尖点突变对相邻木结构建筑火灾突变临界值进行预测具有可行性。  相似文献   
86.
Caesalpinia echinata (brazilwood or Pernambuco wood) comprises a complex of three morphological leaf variants, characterized by differences in the number and size of the pinnae and leaflets, and occurring in allopatric and sympatric populations. The present study evaluates the utility of the chloroplast DNA trnL intron in a phylogenetic analysis of the three leaf variants along with other species of Caesalpinia and generic relatives. Our study supports the hypothesis that the name C. echinata designates a species complex and provides evidence that one of the forms, the highly divergent C. echinata large-leafleted variant, represents a distinct taxon.  相似文献   
87.
There is evidence that the replacement of carbon-intensive products with bio-based substitutes (‘material substitution with biomass’) can be highly efficient in reducing greenhouse gas (GHG) emissions. Based on two case studies (CS1/2) for Austria, potential benefits of material substitution in comparison to fuel substitution are analysed. GHG savings are calculated according to default IPCC approaches (Tier 2 method assuming first-order decay) and with more realistic approaches based on distribution functions. In CS1, high savings are achieved by using wood residues for the production of insulating boards instead of energy. The superiority of material substitution is due to the establishment of a long-term carbon storage, the high emission factor of wood in comparison to natural gas and higher efficiencies of gas-fired facilities.The biomass feedstock in CS2 is lignocellulosic ethanol being used for bio-ethylene production (material substitution) or replacing gasoline (fuel substitution). GHG savings are mainly due to lower production emissions of bio-ethylene in comparison to conventional ethylene and significantly lower than in CS1 (per unit of biomass consumed). While CS1 is highly robust to parameter variation, the long-term projections in CS2 are quite speculative.To create adequate incentives for including material substitution in national climate strategies, shortcomings of current default accounting methods must be addressed. Under current methods the GHG savings in both case studies would not (fully) materialize in the national GHG inventory. The main reason is that accounting of wood products is confined to the proportion derived from domestic harvest, whereas imported biomass used for energy is treated as carbon-neutral. Further inadequacies of IPCC default accounting methods include the assumption of exponential decay and the disregard of advanced bio-based products.  相似文献   
88.
Given the excessive use pressure on forests, characterisation of the major users of forest resources can help guide conservation efforts. This study examines whether socio-economic variables explain domestic wood use in an area of Atlantic forest in the community of Três Ladeiras (Pernambuco, north-east Brazil). Socio-economic data were collected from 62 households, and geometric measurements of wood products in each household were taken to calculate the wood volume. An informant in each household indicated the average replacement time for each type of wood use. Data were analysed for static volume (wood volume found at the time of the visit) and dynamic volume (rate of wood consumption, calculated as the ratio between volume and replacement time). Multiple regression analyses were performed to determine the relationships between wood volume (static and dynamic) and the number of species used; independent variables including monthly family income, number of residents, average age of heads of the household, age of oldest household member, average residence time of heads of the household, average education level of heads of the household and education level of the most educated household member. Monthly income was inversely related to the static wood volume (adjusted R 2 = 17.6%, p < 0.001), rate of wood consumption (adjusted R 2 = 23.0%, p < 0.001) and number of species used (adjusted R 2 = 22.3%, p < 0.001) and was the most important predictive variable for these three outcomes. Other factors such as average education level and average age of heads of the household were also explanatory variables of the total rate of wood consumption, as these two variables, together with monthly family income, explain 31.3% of the total dynamic volume. Given the high importance of income in our study, we suggest that future conservation strategies give special attention to the poorest members of the community.  相似文献   
89.
采用不同的吸附剂对木浆造纸黑液酸析木质素后的滤液进行吸附处理研究,并测定其CODcr去除率和脱色率。对滤液原料(2#)的吸附工艺条件进行了考察。结果表明,在四种吸附剂中,粉末活性炭的吸附性能最好。采用粉末活性炭作为吸附剂处理滤液原料(2#)较好工艺条件为:用量为6 g,吸附时间为2.5 h~3 h,吸附温度为60℃。  相似文献   
90.
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