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自19世纪60年代,美国爱荷华州立大学Csanyi教授成功制备泡沫沥青以后,泡沫沥青逐渐被作为再生剂应用于路面再生技术中。泡沫沥青冷再生技术在路面中被广泛应用,首先将需要再生利用的沥青旧路面,经过铣刨、翻挖、回收等多种工艺,再次拌和形成符合规范要求的沥青路面再生混合料,再生过程中的关键在于泡沫沥青。泡沫沥青是指通过特制的发泡设备,向已加热的普通基质沥青中加入部分水和空气,水在高温条件下气化形成水蒸气泡,普通基质沥青与水蒸气泡接触后迅速将其包裹住,熔融状态的热沥青体积急剧膨胀,就形成了泡沫沥青。本文通过查阅大量文献结合已做试验,简要提出几点泡沫沥青冷再生技术试验中出现的问题。 相似文献
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以对苯二甲醇(PXG)为交联剂,萘为芳烃原料,在对甲苯磺酸的催化作用下,合成了沥青树脂。研究中考察了沥青树脂的多种性能参数。结果表明:沥青树脂是萘与对苯二甲醇结合而成的低聚体混合物,固化后具有良好的热稳定性,是一种新型的耐热树脂。 相似文献
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川崎钢铁公司水岛厂焦油蒸馏车间对煤焦油蒸馏后的各种馏分进行分离精制,残渣经改质后作为沥青销售。在沥青中特别是出口沥青因以固体出厂,所以需对热沥青用水冷却固化。而固体沥青容易破碎而产生粉状沥青,装卸时引起扬尘,污染环境。对此,该厂通过对固体沥青进行筛分处理去除粉状沥青后,将其添加到煤中。粉状沥青以沥青浆加以收集后,经脱水、溶解和再冷却制沥青产品。1工艺流程焦油蒸馏和粘结剂沥青的生产流程包括煤焦油配合、焦油连续蒸馏、沥青改质、沥青冷却和沥青贮存等工序。图1为沥青冷却工序的流程。改质沥青贮存于高架槽,自流入冷却… 相似文献
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介绍国内外多种减压渣油的组成和形态分析结果,着重剖析沥青质、胶质的结构。列举了固定床渣油加氢前后三组分的特点;概括了渣油重溶剂脱沥青油杂质的残留率及加氢后数据;阐述了Ni和V的存在形态及反应转化、沥青质中氮化物种类及脱氮催化剂的现状。针对渣油加氢催化剂结焦、金属沉积、氮化物中毒问题,指出应注意的事项,渣油加工倾向于采用溶剂脱沥青-重蜡油加氢-催化裂化组合工艺。 相似文献
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路面沥青混凝土配合比设计属于路面工程施工中最为关键的工作内容,配合比的适用性会对公路路面施工质量产生关键性影响。在进行路面沥青混凝土配合比试验设计时,应选择科学合理的设计方法,优先以马歇尔法为主,严格进行原材料选择、沥青选择、集料级配设计、沥青混凝土试验拌和、确定沥青混凝土最佳用量等相关过程的质量控制,才能真正做好沥青混凝土材料配合比的优化设计工作。 相似文献
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沥青混凝土心墙是水利工程中大坝的主要防渗体,其施工质量直接影响到大坝的防渗质量。沥青混凝土骨料生产系统位置的选择、拌和设备的选择,沥青混凝土现场铺筑试验,配合比及混合料原材料性能试验等工作,都是沥青混凝土心墙施工前必须重视的准备工作,关系到混凝土心墙最终的施工质量。 相似文献
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目的建立检测疫苗中Triton X-100残留量的比浊法,并进行方法学验证。方法将TritonX-100与5%苯酚溶液充分混匀后,室温静置15 min,采用比浊法测定340 nm处吸光度值,与经同样处理的标准品绘制的标准曲线比较,计算样品中残留TritonX-100的浓度。由4名试验人员连续3 d测定12次,评价不同试验人员建立标准曲线的成功率;由同一试验人员在同一试验内和不同时间内及由4名试验人员在不同时间内分别测定低(15μg/ml)、中(25μg/ml)、高(45μg/ml)3个不同浓度的TritonX-100的浓度,验证该方法的精密度和准确度;并检测BSA对试验准确度和精密度的影响。结果 4名试验人员连续3 d的12次检测结果均满足标准曲线的成立条件,成功率为100%;同一试验人员在同一试验内对低、中、高3个不同浓度的TritonX-100溶液重复测定10次,变异系数分别为分别为5.33%、1.19%和1.39%,回收率分别为99.33%、105.60%和110.67%;同一试验人员在不同时间内连续测定3次,变异系数分别为4.94%、7.49%和3.46%,回收率分别为87.75%、93.85%和95.51%,4名试验人员在不同时间内连续测定3次,变异系数在1.73%~12.17%之间,回收率在89.55%~99.26%之间,灵敏度为10μg/ml,具有良好的精密度和准确度;BSA对试验准确度和精密度无显著影响。结论该方法快捷、简便,可灵敏、准确地定量检测TritonX-100的含量,可用于疫苗样品中残留TritonX-100的质量控制。 相似文献
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运用工业工程技术对已有清洗机的工作过程进行研究,并制定改善设计方案,将已有清洗机的单工作台返回式输送改造为双工作台返回式输送,以最低的费用投入,实现清洗机效率的提高,消除了清洗机和工人相互等待的状况。 相似文献
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Michel Lafontaine Catherine Gendre Yves Morele Gilbert Laffitte-Rigaud 《Polycyclic Aromatic Compounds》2013,33(3-4):579-588
In order to determine the respective contribution of cutaneous and respiratory exposure to urinary PyOH excretion, some experimental follow-ups were carried out during cathode relining in the aluminum industry, leading to qualitative (excretion profiles) and quantitative assessments (excreted PyOH/inhaled pyrene). The procedure was as follows: no exposure on Monday, Wednesday, and Friday; polluting operations on Tuesday and Thursday without or with different protections. For workers with cutaneous protection only, a significant peak of PyOH concentration is observed at the postshift, which is followed by a fast decrease to the background level. For workers with respiratory protection, the maximum is in the shape of a plateau which extends for several hours after the postshift and then decreases slowly. For people with contaminated working clothes, a significant amount of PyOH is excreted on the days with no exposition. The mean ratio of urinary excreted PyOH to inhaled pyrene dose is 15.3% for workers with cutaneous protection and 24.5% for workers with no protection. 相似文献
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Andrea Spinazzè Andrea Cattaneo Davide Campagnolo Valentina Bollati Pier Alberto Bertazzi Domenico M. Cavallo 《Aerosol science and technology》2016,50(8):812-821
The objective of this study was to obtain the multi-metric occupational exposure assessment to graphene family nanomaterials (GFNs) particles of workers engaged in the large-scale production of graphene. The study design consisted of the combination of (i) direct-reading instruments, used to evaluate the total particle number concentrations relative to the background concentration (time series with spatial approach) and the mean size-dependent characteristics of particles (mean diameter and surface-area concentration) and (ii) filter-based air sampling for the determination of size-resolved particle mass concentrations. The data obtained from direct reading measurement were then used to estimate the 8-h time weighted average (8-h TWA) exposure to GFNs particles for workers involved in different working tasks. Workers were generally exposed to 8-h TWA GFNs particle levels lower than the proposed reference value (40,000 particle/cm3). Furthermore, despite high short-term exposure conditions were present during specific operations of the production process, the possibility of significant exposure peaks is not likely to be expected. The estimated 8-h TWA concentration showed differences between the unexposed (<100 particle/cm3; <0.05 µg/m3) and exposed subjects (mean concentration ranging from 909 to 6438 particle/cm3 and from 0.38 to 3.86 µg/m3). The research outcomes can be of particular interest because the exposure of workers in real working conditions was assessed with a multi-metric approach; in this regard, the study suggests that workers who are directly involved in some specific working task (material sampling for quality control) have higher potential for occupational exposure than operators who are in charge of routine production work.
© 2016 American Association for Aerosol Research 相似文献
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Catherine Gendre Michel Lafontaine Yves Morele Jean-Paul Payan Patrice Simon 《Polycyclic Aromatic Compounds》2013,33(3-4):761-769
Biomonitoring of workers was carried out in three working areas--an artificial target factory, an aluminum plant, and an electrometallurgy plant--to assess exposure to PAHs. All the 48 hr-voided urine samples of the exposed workers were collected and the 3-hydroxybenzo[ a ]pyrene (3-OHB a P) and 1-hydroxypyrene (1-OHPy) analyzed according to procedures using automated column-switching high-performance liquid chromatography. The exposure profiles indicate an important lag between the excretion of the two metabolites: the maximum of 3-OHB a P urinary excretion is observed 10 to 17 hr after the 1-OHPy maximum, with a much closer correlation ( r = 0.81) than that obtained with both metabolites in real time ( r = 0.21). This delayed excretion agrees with data from animal intoxication studies (intravenous administration or inhalation). Mean ratios of 1-OHPy to 3-OHB a P were studied without lag (varying from 2,230 to 15,330) and with a lag of 16 hr (varying from 940 to 8,390). 相似文献
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随着采煤机械化程度的不断提高,综采工作面进度不断加快,煤炭“安全质量标准化达标”要求的逐步深化,原始的综采工作面小绞车牵引拖移电缆,给电缆的频繁移动与收缩带来了很多困难。因此提高电缆拖移装置科学性,使拖缆装置的操作更为适用、简便、安全、可靠刻不容缓。新型BY-60/120电缆拖动装置在晋华宫矿大采高工作面的应用减少了作业人员,减轻了劳动强度,提高了作业速度和生产效率。 相似文献
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显微摄影中的几个要点——柯勒氏(Koehler)照明法、视场光圈和孔径光圈的调整与正确使用 总被引:1,自引:0,他引:1
目前,较先进的显微镜均配备了自动化程度很高的显微摄影装置,这为科技工作者拍摄显微照片提供了方便条件。但要获得一张高质量的理想的显微照片,还必须正确熟练地掌握显微摄影的操作技术。例如:显微镜的调整技术;显微摄影的拍摄技术;显微摄影底片和照片的后期加工技术等。本文重点介绍显微镜调整技术中的柯勒照明法、视场光圈和孔径光圈的调整与使用。因为在显微摄影中这几点是最重要的,也是最基本的操作程序,而在实际工作中往往被许多人忽视,甚至是错误的操作。 相似文献