复合型阻燃剂对无醛超低密度纤维板性能的影响

采用磷-氮-硼(P-N-B)复合阻燃剂以及豆粕胶黏剂复配异氰酸酯(PMDI)胶黏剂制备无醛超低密度纤维板(NUDF),探讨阻燃剂添加量对无醛超低密度纤维板物理力学性能、甲醛释放量以及阻燃性能的影响。研究结果表明:随着阻燃剂添加量(0~8%)增加,NUDF的物理力学性能和甲醛释放量均有所降低,氧指数逐渐升高,总热释放量降低,纤维板成炭现象更明显,可燃性显著降低。当阻燃剂添加量6%时,NUDF综合性能较优,内结合强度0.41 MPa、静曲强度14.5 MPa,24 h吸水厚度膨胀率8.1%,甲醛释放量2.0μg/g,燃烧长度80 mm,相同测试时间内不易被引燃,氧指数32.5%,600 s总热释放量12 MJ/m^2。纤维板达到GB 8624—2012平板状建筑材料难燃B1~C级,产烟等级满足S1级,具有良好力学性能、环保和阻燃性能。锥形量热分析表明:随着阻燃剂添加量的增加,燃烧过程中基本呈现总热释放量降低、总烟量升高、CO产率增大和CO 2产率减小的趋势。     

氢氧化铝改性丙烯酸酯乳液胶黏剂及阻燃性能研究

采用机械共混方式获得Al(OH)3改性丙烯酸酯乳液胶黏剂,研究了分散剂种类及用量、增稠剂用量和Al(OH)3用量对胶黏剂基本性能和流体力学性能的影响。结果表明,在分散剂六偏磷酸钠(SHMP)用量为0.35%、增稠剂羟乙基纤维素(HEC)用量为0.20%和阻燃剂Al(OH)3用量为30%时,改性后丙烯酸酯乳液胶黏剂的性能较好,黏度为1 360 m Pa·s,p H值为5.45,贮存30天后稳定性较好,氧指数达到32;流体力学性能研究表明乳液体系为非牛顿假塑性流体弹性体系。阻燃性能研究表明Al(OH)3改性后丙烯酸酯乳液胶黏剂的热释放速率和烟释放量大大降低,CO生成量降低50%以上,引燃时间由60 s延长至77 s,热释放速率峰值由528 k W/m2降为165 k W/m2,燃烧速率为明显减缓(80 s至110 s),质量损失速率明显降低,有较好的阻燃性。     

磷酸三聚氰胺复配硼酸锌阻燃中密度纤维板的燃烧性能

选用磷酸三聚氰胺与硼酸锌复配,制备阻燃中密度纤维板(MDF),并采用锥形量热仪测试其燃烧性能,分析复配阻燃剂对板材燃烧性能的影响.结果表明:复配阻燃剂可有效提高MDF试材的阻燃抑烟性能,降低其热释放速率、总热释放量、产烟速率、总产烟量、CO及CO2生成速率,以磷酸三聚氰胺和硼酸锌等质量复配时,MDF试材的阻燃效果最优.     

Fe_2O_3/聚磷酸铵对聚氨酯木粉复合发泡材料的阻燃抑烟性能

为研究氧化铁(Fe_2O_3)与聚磷酸铵(APP)对聚氨酯木粉复合发泡材料(FWPC)的阻燃效果和抑烟性能,制备了添加不同质量分数Fe_2O_3和APP的FWPC试样。采用锥形量热仪测试样品的燃烧性能、热重分析仪测试样品的热稳定性;采用傅里叶红外光谱对燃烧后的残炭官能团进行分析,研究添加不同比例的Fe_2O_3和APP对聚氨酯木粉复合发泡材料的阻燃和抑烟性能的影响。结果表明:1)与空白对照样相比,添加质量分数为2%的Fe_2O_3和18%的APP的试样点燃时间(TTI)延迟了66.7%,热释放速率(HRR)和热释放速率峰值(PHRR)分别下降了33.9%和39.8%,有效燃烧热(EHC)也下降了12.6%,说明添加一定比例的Fe_2O_3和APP对FWPC的阻燃作用明显;2)添加3%Fe_2O_3和17%APP时,试样的总烟释放量(TSR)、总烟产量(TSP)和比消光面积(SEA)分别比空白对照样下降38.2%,37.4%和27.1%,说明Fe_2O_3和APP对FWPC具有明确的阻燃及抑烟作用;3)Fe_2O_3和APP同时加入FWPC时,分解温度比空白对照样有所上升,特别是添加2%Fe_2O_3和18%APP试样的质量残余率高达65.0%,说明加入适宜比例的Fe_2O_3和APP可以提高凝聚相阻燃效果,从而提高FWPC的热稳定性;4)傅里叶红外光谱显示,在1 050和1 429 cm~(-1)处,添加Fe_2O_3和APP的试样的吸收峰强度明显弱于空白对照样,这两处强吸收峰分别归属于C—O伸缩振动和CH_2剪式振动或者弯曲振动,表明燃烧产物中存在脂肪族醇类物质,不加阻燃剂的聚氨酯发泡木塑复合材料燃烧完全,而加入Fe_2O_3和APP会影响残炭中官能团的组成结构。总体上看,在FWPC中添加适宜比例的Fe_2O_3和APP后,试样的HRR和TSR均有明显下降,说明2种添加剂对FWPC具有很好的阻燃及抑烟效果。     

无机镁铝水滑石制备阻燃MDF的性能分析

采用无机镁铝水滑石阻燃剂(Mg Al-LDH)制备阻燃中纤板(MDF),探讨其用量对MDF阻燃及力学性能的影响,并与三聚氰胺磷酸盐(MP)进行对比。结果表明:随着Mg Al-LDH添加量增加,其阻燃抑烟作用更明显;添加量为15%时,其阻止热量释放效果达到MP添加量10%的效果,但抑烟性更优。添加Mg Al-LDH,可使MDF的力学强度降低,但添加量为10%时,阻燃MDF的力学性能仍满足GB/T 11718-2009普通型产品的要求。     

用CONE法研究木材阻燃剂FRW的抑烟性能

采用锥形量热仪 (CONE)法系统地测定了新型木材阻燃剂FRW的抑烟性能 ,讨论了FRW对木材燃烧时发烟及烟气毒性的影响 ,并与Dricon阻燃剂进行了对比。结果表明 ,当热辐射功率为 5 0kW·m- 2 时 ,FRW阻燃处理木材的烟化率SR、比消光面积SEA、二氧化碳浓度CO2 及二氧化碳产率YCO2 比未处理木材显著降低 ;FRW阻燃处理对木材燃烧时一氧化碳的生成元显著影响 ;FRW与Dricon均具有很强的抑烟作用 ,二者的抑烟效力相当     

阻燃型水性丙烯酸木器涂料的研究

为了改善涂料的阻燃性能,以水性丙烯酸乳液为基料制备了水性丙烯酸阻燃木器涂料。探讨聚磷酸铵(APP)-漂珠协效阻燃剂对水性丙烯酸阻燃涂料阻燃性能的影响。采用氧指数(OI)和锥形量热仪(CONE)试验对阻燃性能进行分析,结果表明:在APP的基础上添加漂珠所组成的协效阻燃涂料氧指数可达到28.7%,相比于未添加阻燃剂的水性丙烯酸涂料提高了31.8%。同时,协效阻燃剂能够降低涂料的热释放速率和烟释放速率,减少总热释放量和烟释放量;相比于仅添加APP的阻燃涂料,APP-漂珠协效阻燃涂料在燃烧过程中峰值热释放速率(pk HRR)降低了17.3%,烟释放总量(TSP)降低了12.9%,并且具有更好的阻燃抑烟效果,有利于促进木材成炭,减少CO和CO_2等烟雾毒气释放,降低火灾危险。     

环保无卤阻燃剂对酚醛泡沫塑料性能影响

以苯酚(4.26 mol)、多聚甲醛(7.28 mol)、甲醛(1.24 mol)为原料,NaOH为催化剂,采用逐步共缩聚的合成工艺,制备高固含量甲阶酚醛树脂,选择3种环保型无卤阻燃剂(APP、MP、LM-NPP 8081)复合酚醛树脂制备酚醛泡沫,通过测试泡沫力学性能、阻燃性能、易碎性、耐热性能和导热性能等,研究阻燃剂的种类及添加量对酚醛泡沫性能影响.结果表明:3种阻燃剂都能明显提高泡沫的阻燃性,对泡沫的耐热性能和导热系数的影响不是很显著.当阻燃剂添加量为8％时,阻燃剂复合的酚醛泡沫的机械性能较优,并且MP复合酚醛泡沫的综合性能较好,此时MP复合泡沫的氧指数为55.22％,压缩强度为0.30 MPa,弯曲强度为0.28 MPa,掉渣率为34.40％,导热系数为0.045 W/(m·K),300℃残炭量87.50％,600℃残炭量61.12％.结果表明3种阻燃剂中MP是一种较适合酚醛泡沫体系的阻燃剂.     

ASD阻燃剂对落叶松材阻燃性能的影响

为制备具有良好阻燃性能的落叶松(Larix gmelinii)结构材,采用不同质量分数的ASD阻燃剂以真空加压的方式处理落叶松材,通过锥形量热仪测试和热重分析来考察阻燃剂对落叶松材的阻燃效果,并确定最佳的ASD阻燃剂质量分数。结果表明:经ASD阻燃剂处理后,落叶松材总热释放量和烟释放总量明显降低,降低幅度随ASD阻燃剂质量分数的增大而提高;CO产率升高,CO_2产率明显降低,升高或降低幅度随ASD阻燃剂质量分数的增大而增大,CO产率和CO_2产率之和明显下降,说明ASD阻燃处理明显抑制了落叶松材的燃烧。综合考虑阻燃效果和成本,ASD阻燃剂的最佳质量分数为50%,此时与落叶松素材相比,总热释放量降低了56.46%,烟释放总量降低了88.20%。经ASD阻燃剂处理的落叶松材初始分解温度有所降低,残余物质量分数从18.26%提高到41.06%。经ASD阻燃剂处理前后的落叶松材锥形量热仪燃烧测试后表面形态有明显差异:素材燃烧后的木炭表面松软,断层较大;阻燃处理材表面形成了致密的炭质保护层,有效延缓抑制了落叶松材的燃烧。ASD阻燃作用主要归因于对木材的催化成炭作用。     

用CONE法研究木材阻燃剂FRW的阻燃机理

采用锥形量热仪(CONE)法对复合木材阻燃剂FRW处理紫椴木材(FZ)、FRW的组分磷酸脒基脲(GUP)处理紫椴木材(GZ)、硼酸处理紫椴木材(BZ)和未处理的紫椴木材(UZ)的燃烧性进行了系统的测定，通过对上述试样在燃烧时的热释放、质量变化、烟气产生以及尾气成分等实验数据的综合对比分析，讨论了阻燃剂的作用机理。结果表明：1)FRW阻燃剂显著降低了木材的热释放速率(RHR)、总热释放量(1FHR)、有效燃烧热(EHC)、质量损失速率(MLR)、烟比率(SR)、比消光面积(SEA)、CO2的浓度及产率(Yco2)；2)GUP与硼酸之间存在显著的阻燃协同效应；3)FRW阻燃木材的MLR曲线与RHR曲线相似，失重和热释放主要发生在有焰燃烧阶段；4)FRW阻燃处理能显著提高木材燃烧时的成炭率，说明催化成炭是FRW阻燃机理的主要方面。     

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.