水蒸气活化法制备松子壳活性炭的研究

以废弃的松子壳为原料,采用水蒸气活化法制备松子壳活性炭,系统研究了炭化温度、活化温度、活化时间、活化剂用量等关键工艺因素对活性炭产品性能的影响,分析其对碘吸附值和亚甲基蓝吸附性能的影响。结果显示,松子壳活性炭最佳工艺条件为:炭化温度为500℃、活化温度为860℃、活化时间为90 min、水蒸气流量为2.5 m L/min,此时松子壳活性炭得率为26.08%,碘吸附值为1 338 mg/g,亚甲基蓝吸附值为300 mg/g。松子壳活性炭孔径主要集中在3 nm左右,其平均孔径为2.396 nm,BET比表面积为105 2.68 m~2/g,总孔容积为0.630 6 cm~3/g,微孔容积为0.355 8 cm~3/g,占总孔容积的56.43%。     

以浸提兴安落叶松锯末为原料制备高比表面积活性炭

以超声波浸提法提取阿拉伯半乳聚糖后的兴安落叶松锯末为原料,KOH为活化剂,惰性气氛条件下程序升温活化,研制高比表面积活性炭.系统分析了碱料比、活化温度、活化时间、活化剂加入方式与种类、预炭化对活性炭比表面积、碘吸附值和得率的影响.以低温液氮吸附分析了活性炭的比表面积,通过苯酚的等温吸附测试了活性炭的吸附性能.结果表明浸提锯末为制造高比表面积活性炭的适宜原料,在最佳条件500℃预炭化1 h,750℃活化1 h,固体KOH为活化剂,碱料比41(质量比)时制得的活性炭比表面积为2 659.4 m2/g,对苯酚的吸附容量为570 mg/g.     

水蒸气活化法制备松籽壳活性炭工艺

研究了水蒸气法活化制备松籽壳活性炭的工艺条件,探讨了炭化温度、活化温度、活化时间和水蒸气用量对活化效果的影响。结果表明最佳工艺条件为:炭化温度500℃、活化温度950℃、活化时间120 min和水蒸气用量为炭化料的1.8倍,制备的活性炭碘值1144 mg/g,亚甲基蓝吸附值171 mL/g,产品得率15.6%。这些指标与木质活性炭相当,且投资少,能耗低,具有良好的社会效益与经济效益。     

以浸提兴安落叶松锯末为原料制备高比表面积活性炭

以超声波浸提法提取阿拉伯半乳聚糖后的兴安落叶松锯末为原料，KOH为活化剂。惰性气氛条件下程序升温活化，研制高比表面积活性炭。系统分析了碱料比、活化温度、活化时间、活化剂加入方式与种类、预炭化对活性炭比表面积、碘吸附值和得率的影响。以低温液氮吸附分析了活性炭的比表面积，通过苯酚的等温吸附测试了活性炭的吸附性能。结果表明：浸提锯末为制造高比表面积活性炭的适宜原料，在最佳条件：500℃预炭化1h，750℃活化1h，固体KOH为活化剂。碱料比4：1（质量比）时制得的活性炭比表面积为2659．4m^2／g，对苯酚的吸附容量为570mg／g。     

山杏壳制备活性炭的最佳工艺研究

以山杏壳为原料,用正交试验法,分别采用氯化锌、水蒸气活化法制备杏壳活性炭,并测定吸附能力,优选制备杏壳活性炭的最佳工艺参数,为杏壳活性炭的产业化生产提供技术依据。研究结果表明,以氯化锌为活化剂制备杏壳活性炭的最佳工艺参数为:氯化锌溶液浓度50%,料液比1∶1,活化温度500℃,活化时间90min;水蒸气活化法制备杏壳活性炭的最佳工艺参数为:水蒸气流量5mL/min,活化温度900℃,活化时间120min。在本试验确定的最佳工艺条件下,以氯化锌为活化法制备的活性炭得率为41.83%,碘吸附值为948.06mg/g,亚甲基蓝吸附值为133.42mg/g;以水蒸气活化法制备的杏壳活性炭得率为48.11%,碘吸附值为1001.67mg/g,亚甲基蓝吸附值为153.05mg/g,2种方法制备的杏壳活性炭均具有较强的吸附能力。     

木屑炭流态化活化工艺研究

以木屑炭为原料,水蒸气为活化剂,采用流态化工艺制备活性炭,研究了活化温度、载气流量、水蒸气流量、进料速度等因素对活性炭性能的影响。通过正交试验,确定了最佳工艺条件为活化温度870℃、载气流量250 m3/h、水蒸气流量150 m3/h、进料速度54 kg/h。在最佳工艺条件下,产品碘吸附值为1 162 mg/g,得率为31.62%。方差分析表明:对活性炭产率来说,只有活化温度的影响达到显著水平,其它因素的影响均不显著;对活性炭碘吸附值来说,活化温度、水蒸气流量、载气流量3因素的影响均达到显著水平。     

The Activation Process of Fluidization for Sawdust Charcoal

以木屑炭为原料,水蒸气为活化剂,采用流态化工艺制备活性炭,研究了活化温度、载气流量、水蒸气流量、进料速度等因素对活性炭性能的影响.通过正交试验,确定了最佳工艺条件为活化温度870℃、载气流量250 m3/h、水蒸气流量150m3/h、进料速度54 kg/h.在最佳工艺条件下,产品碘吸附值为1 162 mg/g,得率为31.62％.方差分析表明:对活性炭产率来说,只有活化温度的影响达到显著水平,其它因素的影响均不显著;对活性炭碘吸附值来说,活化温度、水蒸气流量、载气流量3因素的影响均达到显著水平.     

农业成型秸秆制备空气净化用活性炭试验研究

研究了以农业秸秆经压块成型后为原料,采用水蒸气活化法制备活性炭工艺。讨论了炭化温度、炭化时间、活化温度和活化时间对活性炭的得率和吸附性能的影响,得到了最佳工艺条件:炭化温度450℃、炭化时间6h、活化温度850℃、活化时间3h。经后处理去灰分后,制得的活性炭的亚甲基蓝吸附值达180 mg·g-1。基本能达到木质净水用活性炭标准要求,具有较大的推广应用前景。     

薄皮核桃壳基活性炭的制备及表征

【目的】以农林废弃物薄皮核桃壳为原料,通过化学活化-高温炭化法制备多孔活性炭材料,优化制备工艺过程,表征吸附性能机理,为薄皮核桃壳的开发利用提供技术指导。【方法】以碘吸附值和亚基甲蓝吸附值为考察指标,进行活化剂的筛选,并进一步考察原料粒度、料液比、活化时间、炭化温度和炭化时间对制备出的活性炭的吸附性能的影响。采用N2吸附-脱附等温线、元素分析仪和FTIR测定了活性炭的孔隙结构、主要元素组成和表面官能团,扫描电镜分析形貌结构,XRD和TG分析活性炭的结晶度和热稳定性。【结果】选用磷酸为最佳活化剂,薄皮核桃壳活性炭的最佳制备工艺条件为:核桃壳粉100目、料液比1:4、活化时间120 min、炭化温度500℃、炭化时间60 min,此工艺条件下制备出的活性炭的碘吸附值为657.42±3.16 mg/g、亚甲基蓝吸附值为248.55±1.94 mg/g。制备出的活性炭的表面积为449.80 m2/g,具有丰富的孔隙结构,孔容积为1.11 m2/g,平均孔径为7.87 nm。碳元素含量为65.56%,结晶度不高,为无定型结构,活性炭在400℃左右发生热降解,主要含有羧基、酚基、醇羟基等活性官能团。【结论】采用磷酸活化法制备出的薄皮核桃壳活性炭的孔隙结构发达,具有良好的吸附性能,碘吸附值和亚甲基蓝吸附值均高于国家标准,具有将废弃物资源循环利用的价值和前景。     

水蒸气法制备橡胶籽壳活性炭的研究

采用橡胶籽壳炭为原料,以水蒸气为活化剂制备吸附性能优良且得率高的活性炭。通过正交试验设计,研究活化温度、活化时间及水蒸气用量对活性炭吸附性能的影响。得到最佳活化工艺条件为:橡胶籽壳炭量1.0 kg,活化温度880℃,活化时间40 m in,水蒸气用量8 kg/h。制得的优质橡胶籽壳活性炭的亚甲基蓝脱色力240 mg/g,碘值1 113 mg/g,强度94.2%,得率40.5%。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.