地铁列车车厢火灾特性研究

在用报纸引燃点火情况下,采用地铁列车实体模型研究了地铁列车的火灾场景,得出了模拟地铁列车在火灾中的热释放速率、烟气浓度、温度的变化规律.研究表明一节列车车厢最大热释放速率为5 MW左右;如果两侧沙发同时引燃,最大热释放速率为10 MW;该点火方式下引起火灾的燃烧极不充分,烟气中NO含量很低,几乎没有SO2、HCN的释放;烟气主流沿着而不贴着屋顶向外蔓延.     

烟叶燃烧烟气中HCN扩散范围计算

采用异烟酸—巴比妥酸法测定烟叶燃烧烟气中HCN的含量,发现烟叶燃烧烟气中HCN的总含量为758.2μg/g,其中粒相物中HCN含量为524.7μg/g,气相物中HCN含量为233.6μg/g。根据实验数据,利用高斯非正常排放模型计算大气稳定度、风速对烟叶仓库火灾中HCN气体扩散的影响,计算结果表明:大气稳定度为F,风速为1.5 m/s时,最不利于HCN气体扩散。在此气象条件下,分别对5、10、15、20、25、30 min时,假定烟叶仓库火灾中HCN气体扩散的范围进行计算,研究结果可为烟叶仓库火灾救援和人员疏散提供借鉴。     

聚合物基建筑保温材料的热行为及燃烧行为

对模塑聚苯乙烯泡沫板(EPS),挤塑聚苯乙烯泡沫板(XPS)和聚异氰酸酯-聚氨酯泡沫板(PIR-PU)的热分解行为、燃烧行为、燃烧烟气中的主要毒害气体和热裂解产物进行了研究.结果表明:PIR-PU的初始分解温度和最大热分解温度明显低于EPS和XPS,EPS和XPS的热分解行为基本相同,高温下PIR-PU的残炭率高,而EPS和XPS基本不成炭;PIR-PU的热释放速率、总热释放量、生烟速率和总生烟量均明显低于EPS和XPS,但PIR-PU点燃时间比EPS和XPS短;PIR-PU,EPS和XPS的燃烧烟气中均存在CO和HCN等毒害气体,有效剂量分数(FED值)表明PIR-PU的燃烧烟气毒性最大;PIR-PU热裂解产物中的异氰酸酯衍生物、苯胺衍生物和含氯阻燃剂是其燃烧生成HCN和HCl的主要原因,而EPS和XPS热裂解产物中大量的芳香族衍生物是其生烟量较大的一个重要原因.     

昆明地区绿化树种鲜叶热解和燃烧烟密度

为了解园林绿化树种鲜叶在防火期热解和燃烧的烟气生成特性，用JCY-2型烟密度测定仪对昆明地区13种常见的园林绿化树种鲜叶进行了烟密度测定，分析了13种园林绿化树种的新叶、近成熟叶和老叶的产烟量、最大烟密度值、烟密度等级的关系，为研究管护措施、强度、频率等如何影响园林绿化植物鲜叶热解和燃烧的烟密度提供依据。研究表明：单位质量鲜叶干物质产烟量总体上呈现新叶＞近成熟叶＞老叶的特性；鲜叶质量相近时，含水率越大，烟密度等级越小。     

含氮高分子材料燃烧,热分解氰化氢生成特性的研究

火灾统计表明,建筑物火灾中死伤者的大多数不是由于直接火伤,而是由于烟和有毒气体的影响所造成的.烟和有毒气体的产生主要是来自建筑物内各种可燃物质的燃烧、热分解,因此为研究和评价建筑物火灾中各种可燃物质燃烧生成气体对人体的有害性,了解在火灾时复杂的燃烧条件下,特别是各种温度,不同空气供给条件燃烧生成气体的组成和生成特性是必要的.对于天然或合成高分子材料,燃烧、热分解时都会有CO和CO_2生成,但不同材料由于所含原子种类不同,又会产生特有的有毒气体,含氮材料主要有HCN产生,HCN是一种剧毒而作用极快的毒物,它抑制细胞对氧的利用,毒性约为CO的20倍.含氮材料做为各种纤维制品,     

汽油燃烧烟气的热解吸/气相色谱/质谱分析

采用热解吸进样和气相色谱/质谱联用技术(GC/MS),研究汽油燃烧产生烟气的特征组分以及不同种类载体对汽油燃烧产生的烟气特征组分的影响。实验选择93#汽油原样及其在两种典型常见载体上燃烧产生的烟气作为研究对象,在获得各样品的总离子流色谱图后,利用标准质谱库进行检索确定汽油燃烧烟气的特征组分。结果表明,汽油燃烧烟气中的最常见组分是苯、3-辛稀、邻苯二甲酸-2-甲基-庚酯、己二酸庚酯、邻苯二甲酸丁酯,其中苯和3-辛烯是汽油燃烧烟气的特征组分。热解吸进样和气相色谱/质谱联用技术对火灾现场烟气可以有效地进行鉴定,同时这种方法因为省去了萃取等实验环节而变得更简单。     

尿素热解技术在锅炉烟气脱硝工程中的应用介绍

随着国家环保指标的提高,燃煤电站锅炉烟气排放指标控制的越来越严格,燃煤电站烟气污染物的排放受到了国际和社会的广泛关注。锅炉烟气脱硝在全国各地全面普及,传统的脱硝还原剂液氨的运用受到了安全、地域等因素的限制,尿素热解技术因其安全可靠,逐步成为许多用户的首选。本文介绍了尿素热解技术的流程及其工程实例,并针对运行中出现的问题提出了解决的对策。     

常见合成纤维燃烧烟气组成规律的试验研究

采用涤纶、锦纶、腈纶三种常见合成纤维为试验研究对象,对它们在模拟居室火灾中自然通风条件下的烟气主要组分随时间的变化规律进行试验研究,并讨论各种烟气组分的相互联系.     

离子色谱法在火灾烟气分析中的应用研究

离子色谱法是分析火灾烟气成分的主要分析方法之一。采用离子色谱法对火灾烟气中常见毒性气体相对应的阴离子F^-、Cl^-、NO2^-、SO4^2-、Br^-、NO3^-、PO4^3-等进行了分析研究，给出了离子色谱法在实际火灾中的应用案例。     

阻燃电工套管热解烟气毒害物分析

采用气质联用分析法对u-PVC阻燃电工套管热解烟气中苯、甲苯进行分析研究。设定管式炉的加热温度为710℃,在材料产烟毒性装置上进行热解。通过大气采样器(流速1.0L/min),用环己烷溶液吸收u-PVC阻燃电工套管的热解烟气,取离心后的环己烷上层清液进行测试。结果表明:在优化条件下可获得满意的分离度和结果。热解产物主要毒性组分苯浓度为58.33mg/m3,甲苯浓度为34.12mg/m3。     

Ammonium nitrogen removal from coking wastewater by chemical precipitation recycle technology

Ammonium nitrogen removal from wastewater has been of considerable concern for several decades. In the present research, we examined chemical precipitation recycle technology (CPRT) for ammonium nitrogen removal from coking wastewater. The pyrolysate resulting from magnesium ammonium phosphate (MAP) pyrogenation in sodium hydroxide (NaOH) solution was recycled for ammonium nitrogen removal from coking wastewater. The objective of this study was to investigate the conditions for MAP pyrogenation and to characterize of MAP pyrolysate for its feasibility in recycling. Furthermore, MAP pyrolysate was characterized by scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) as well as X-ray diffraction (XRD). The MAP pyrolysate could be produced at the optimal condition of a hydroxyl (OH⁻) to ammonium molar ratio of 2:1, a heating temperature of 110 °C, and a heating time of 3 h. Surface characterization analysis indicated that the main component of the pyrolysate was amorphous magnesium sodium phosphate (MgNaPO₄). The pyrolysate could be recycled as a magnesium and phosphate source at an optimum pH of 9.5. When the recycle times were increased, the ammonium nitrogen removal ratio gradually decreased if the pyrolysate was used without supplementation. When the recycle times were increased, the ammonium nitrogen removal efficiency was not decreased if the added pyrolysate was supplemented with MgCl₂·6H₂O plus Na₂HPO₄·12H₂O during treatment. A high ammonium nitrogen removal ratio was obtained by using pre-formed MAP as seeding material.     

Modelling of hydrogen cyanide formation in room fires

A chemical kinetics model for calculation of the formation of hydrogen cyanide (HCN) has been made. The combustion of a mixture of methylamine and ethylene has been modelled using the stationary laminar flamelet concept. The flamelet calculations are based on several thousand elementary reaction steps including the chemical kinetics of HCN in combustion. The flamelets for both cold (293 K) and hot (1000 K) combustion product recycling have been calculated. The effect of strain is also included in the flamelet calculations. Scalar dissipation rates from 0.01 s⁻¹ to extinction values have been varied. Also the effect of radiation is included in the flamelet state relationships.

Separate flamelet sets for various levels of radiation, from adiabatic up to 30% radiation losses, incremented by 1%, have been made. In the flow field calculation, the flamelet options may be used either as adiabatic, constant radiation or an interpolation between flamelet sets of different radiation.

The chemical kinetics model, incorporated into a Reynolds-Averaging Navier–Stoke (RANS) type CFD code, has been used to simulate two laboratory fire tests of the combustion of nylon. Changing the size of the opening in the test room varied the ventilation between the two tests. Flamelet sets for a mixture of methylamine and ethylene with nitrogen content close to that of nylon were used in these simulations. The simulations were made with and without recycling the combustion products back to the fire.

The calculations show that recycling of the combustion products to the fire increases the formation of HCN and CO. Similarly, a lowered ventilation rate increases the formation of these species. The calculated temperatures and main species concentrations, including HCN, agree reasonably well with the trends in the laboratory measurements.     

无皂聚合丙烯酸乳液与无机粉料复合体的性能研究

本工作经无皂聚合制备了羧基含量为10%的丙烯酸乳液。对比有皂聚合的丙烯酸乳液,无皂聚合的乳液与无机粉料体现出更好的相容性。测试的结果表明,无皂聚合的乳液与不同无机粉料的复合体具有不同的耐水性力学强度,这主要是由于乳液中胶体表面羧基的反应活性较高。     

一种聚羧酸高效减水剂的合成及其减水机理研究

试验采用不同聚合度的甲氧基聚乙二醇合成丙烯酸类单体,在链转移剂和引发剂存在的情况下,共聚合成了聚羧酸系高效减水剂。对合成的外加剂进行了一些微观测试,初步探讨了聚羧酸系高效减水剂的减水机理。     

溶剂型丙烯酸聚酯外墙涂料

以多元醇与多元酸制成的聚酯,通过接枝合成引入丙烯酸低分子量聚合物成为丙烯酸聚酯,以它为成膜物配制的溶剂型丙烯酸聚酯外墙涂料,具有粘接力强、耐候性好、耐水耐污秽、快干低毒、价格适中、施工方便等特性,可用于墙和门窗等的保护和装饰。     

Isocyanates and hydrogen cyanide in fumes from heated proteins and protein‐rich foods

Toxic compounds in cooking fumes could cause respiratory problems. In the present study, the formation of isocyanic acid (ICA), methyl isocyanate (MIC), and hydrogen cyanide (HCN) was studied during the heating of proteins or frying of protein‐rich foods. Heating was performed in an experimental setup using a tube oven set at 200‐500°C and in a kitchen when foods with different protein content were fried at a temperature around 300°C. ICA, MIC, and HCN were all generated when protein or meat was heated. Individual amino acids were also heated, and there was a significant positive correlation between their respective nitrogen content and the formation of the measured compounds. Gas from heated protein or meat also caused carbamylation in albumin. ICA, MIC, and HCN were also present in fumes generated when meat, egg, and halloumi were fried in a kitchen pan. The levels of ICA were here twice that of the Swedish occupational exposure limit. If ICA, MIC, and HCN in fumes from heated protein‐rich foods could contribute to the risk of airway dysfunction among those exposed is not clear, but it is important to avoid inhaling frying and grilling fumes and to equip kitchens with good exhaust ventilation.     

Fe3O4/聚乙烯磁性复合材料的阻燃性能研究

以高密度聚乙烯为基体树脂,选用FeCl3为填料,使用丙烯酸作为分散剂,采用熔融原位法制备铁氧粒子/聚乙烯复合材料。利用扫描电镜和电子衍射分析该复合材料结构,结果显示制备得到铁氧粒子/聚乙烯复合材料,且磁性粒子均匀分散在树脂基体中。采用电子万能试验机和氧指数测定仪研究了铁氧粒子/聚乙烯复合材料力学性能和阻燃性能,实验结果表明,该结构的磁性高分子材料不仅获得了较好的力学性能,同时还具有良好的阻燃性能。     

地铁站厅中杂货亭火灾场景特性研究

采用地铁站厅中的杂货亭模型实体火灾试验,研究地铁站厅杂货亭的火灾场景,得出了模拟站厅杂货亭在火灾中的热释放速率、烟气浓度、温度、烟密度的变化规律,站厅杂货亭发生轰燃的时间、最大热释放量。火灾中烟气是首先弥漫整个房顶,然后再向下蔓延。     

Neuro-endocrine biomarkers of pollution-induced stress in marine invertebrates

Nitric oxide (NO) is a molecular mediator of the non-specific immune response of vertebrates but production has also been recorded in response to bacterial infection in invertebrates. Together with biogenic amines and cytokines, production of NO in invertebrate phagocytic haemocytes is thought to represent a putative stress response. In this study the hypothesis that NO might be a sensitive biomarker of stress in invertebrates has been tested. The spectrophotometric Griess assay for nitrite and nitrate has been modified so that the final breakdown products of NO are suitable for measurement in invertebrate haemolymph. The assay was linear in the range 1-100 microM with a sensitivity of 4 microM. The baseline NOx measurement in unstressed mussels was 0.74 mM NOx/mg protein. Mytilus edulis were kept at 15 micro C in filtered seawater for at least 2 days prior to exposure to TBTO (0.001-0.1 mg/l) for 24 h. Preliminary results suggest that TBTO perturbs the NO response and that the outlined assay protocol is a sensitive means of detecting those changes. It is proposed that NO measurements potentially offer a highly sensitive, non-invasive means of monitoring stress responses associated with environmental change.     

Assessing the effects of land use on temporal change in well water quality in a designated nitrate vulnerable zone

The nitrate concentration in discharge from the Balmalcolm borehole in Fife, Scotland, has steadily increased from 4.5 mg l(-1) NO3-N in the early 1970s to 11.0 mg l(-1) NO3-N in 1998. Consequently the catchment of the borehole, covering an area of 400 ha has recently been designated a Nitrate Vulnerable Zone under the EC Nitrate Directive [Commission of European Communities L375, (1991) 1]. The sandstone aquifer that supplies the borehole is recharged by water draining from land that is intensively cropped to green vegetables. There is, therefore, a need to identify appropriate land management techniques that will help to abate the nitrate losses from the land and to estimate the length of time that it is likely to take before the abatement is observed as a decrease in well-water concentrations. Estimates of nitrate leaching for the range of crops that have been grown in the catchment over the last 30 years have been made using a balance sheet approach, modified to allow for estimates of denitrification and in-field composting of vegetable crop residues. Integration over the whole catchment using a GIS approach, indicates a steady-state well water [NO3--N] of 23 mg l(-1)--a situation that has not yet been reached. Prediction of the time course of change in well water quality from 1970 (when intensification began) has been made by calculating the travel time from different parts of the catchment both in the saturated and unsaturated zones. The results show good agreement between the measurements and simulation. Well water [NO3-N] under potential future management scenarios have also been investigated using the same approach. The greatest reduction in steady-state concentration, to 9 mg l(-1), is achieved for the scenario of extensification to spring cereals with moderately fertilised grassland. However, the temporal simulations suggest that it would take approximately 100 years before 80% of this change is observed in the well-water, starting from a concentration of 23 mg l(-1) .