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排序方式: 共有8631条查询结果,搜索用时 31 毫秒
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Mirco Wegener Luckman Muhmood Shouyi Sun Alex V. Deev 《American Institute of Chemical Engineers》2014,60(9):3350-3361
The experiments on the capillary breakup of slag jets at high temperatures are presented in this article. The impact of external excitations on the disintegration process was investigated in a furnace with optical access filmed at frame rates up to 10,000 fps. A synthetic calcia‐alumina slag was used to form jets at different temperatures (1570–1660°C) and jet velocities (0.6–1.4 ms?1). The impact of external vibration on the breakup was evident: for low jet velocities, the jet length decreased, the droplet size increased, satellite droplet formation was hindered, and a distinct “pumping mechanism” was observed. For jets with higher velocity, the jet length decreased by 30%, the droplet generation frequency increased from 20 to 250 droplets per second, the drop sizes were uniform, and satellite formation was also suppressed. In this case, the ideal case in which the volume of one wave instability forms one droplet was achieved. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3350–3361, 2014 相似文献
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介绍了PVC-U管道行业的整体情况、PVC树脂及加工助剂的应用情况、建筑用PVC排水管道和压力管道的技术进步,指出了PVC-U管道存在的主要问题和差距,并给出了发展建议。 相似文献
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Pankaj Patial Arifa Shaheen Ishtiaque Ahmad 《Journal of surfactants and detergents》2014,17(2):253-260
New imidazolium gemini surfactants were synthesized by reaction of epichlorohydrin with long chain fatty alcohols furnishing products 2-(alkoxymethyl)oxirane followed by their subsequent treatment with imidazole resulting in the formation of 1-(1H-imidazol-1-yl-3 alkoxy)propane-2-ol which on subsequent treatment with 1,2-dibromoethane and 1,3-dibromopropane resulted in the formation of title gemini surfactants:1,2-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (7), 1,3-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (8), 1,2-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (9), 1,3-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (10), 1,2-bis (1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (11) and 1,3-bis (1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (12). Their identification was based on IR, 1H-, 13C-NMR, DEPT, COSY and mass spectral studies. Their surface active properties were also evaluated on the basis of surface tension and conductivity measurements. 相似文献
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The interactions in the mixed micelles of two triblock polymers, F68 (EO76PO29EO76) and P123 (EO19PO69EO19), with a series of monomeric (dodecyltrimethyl ammonium bromide, tetradecyltrimethyl ammonium bromide and cetyltrimethyl ammonium bromide) and gemini {dimethylene bis(alkyldimethyl ammonium bromide), m-2-m, where m = 10, 12 and 14} cationic surfactants were studied by surface tension and viscosity measurements in aqueous solutions at different temperatures. The mixed micellar and interfacial properties of the binary mixtures were analyzed using Clint, Rubingh, Rosen and Maeda approaches. Both F68 and P123 show weak interactions with the studied cationic surfactants at 298.15 K which become favorable (synergistic) at higher temperatures. Further, the synergistic interactions are more in mixtures of P123 than F68 at higher temperatures. A comparison of the effects of number of EO and PO blocks in triblock polymers on various physicochemical parameters of the mixed micelles has also been made. The unfavorable enthalpy changes are compensated by favorable entropy changes as a result of the hydrophobic effect. The relative viscosity (η r) studies show that the size of the micelles formed by pure P123 is smaller than those of F68. The values of η r for the mixed micelles of F68 show significant variation with chain length of gemini surfactants whereas no such effect is seen in mixtures with P123. 相似文献
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The equilibrium and dynamic surface tension of three sulfosuccinate surfactants at the air/aqueous solution interface were investigated. Wilhelmy plate method was used to determine critical micelle concentration (CMC) and the equilibrium surface tension (γ eq). The dynamic surface tensions in the range 10–100 s were measured by maximum bubble pressure method. The well-known Ward–Tordai equation was employed to analyze the adsorption of the sulfosuccinate surfactants. The parameters and effective diffusion coefficients (D eff) of dynamic surface tension have been calculated and analyzed. The equilibrium surface tension results showed that disodium laureth (3) sulfosuccinate (AEO3-SS), disodium laureth (6) sulfosuccinate (AEO6-SS) and disodium alkyl ethoxy glucoside sulfosuccinate (AEG-SS) are surfactants possessing strong surface activity, adsorbing to the interface rapidly and their γ eq values were in the range 25–32 mN/m. CMC of the three surfactants increases with the number of hydrophilic groups and AEO3-SS has the lowest CMC. According to the values of some dynamic surface tension parameters, AEG-SS is the most hydrophilic surfactant of them and AEO3-SS is energetically more favorable to adsorb to the interface than the others. According to Ward–Tordai equation, the D eff values were calculated, the adsorption mechanism was diffusion controlled at short times and toward the end good evidence was found for an activated-diffusion mechanism with an energy barrier. 相似文献
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Mahmoud R. Noor El-Din Sabrnal H. El-Hamouly Hamed M. Mohamed Marwa R. Mishrif Ahmad M. Ragab 《Journal of surfactants and detergents》2014,17(4):819-831
In this work, water-in-diesel fuel nanoemulsions were prepared with mixed nonionic surfactants. Several mixtures of sorbitan monooleate and polyoxyethylene (20) sorbitan monooleate, with different Hydrophilic–Lipophilic Balance (HLB) values (9.6, 9.8, 10, 10.2 and 10.4) were prepared to achieve the optimal HLB value. Three mixed surfactant concentrations were prepared at 6, 8 and 10 wt% to identify the optimum concentration. Five emulsions with different water contents: 5, 6, 7, 8 and 9 % (wt/wt) were prepared using a high energy method under the optimum conditions (HLB = 10 and mixed surfactant concentration = 10 %). The effect of the HLB value, mixed surfactant concentration and water content on the droplet size has been studied. The interfacial tension and thermodynamic properties of the individual and the blended emulsifiers were investigated. Droplet size of the prepared nanoemulsions was determined by dynamic light scattering and the nanoemulsion stability was assessed by measuring the variation of the droplet size as a function of time. From the results obtained, it was found that the mean droplet size was formed between 49.5 and 190 nm depending on the HLB value, surfactant concentration and water content of the blended emulsifiers. 相似文献
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针对传统拉力型锚杆存在受力集中、锚固体与岩土体界面黏结强度发挥不充分、抗拔承载力偏低的问题,研发了一种新型拉压复合型锚杆。通过开展现场破坏性试验,对拉力型锚杆及拉压复合型锚杆的承载能力、荷载位移曲线及应变数据进行分析,结果表明:3组拉压复合型锚杆TC12-3、TC11-1、TC21锚杆的平均破坏荷载分别提高至拉力型锚杆的2.81,2.01,2.52倍;拉压复合型锚杆套管内的拉力传递损失率最大为20.5%,在自由段内的拉力传递损失率最大仅为6.8%,拉力传递损失主要发生在承压锚固段上;TC12-3锚杆的受拉锚固段长度最短,单位受拉锚固段长度分担荷载最高;TC21-1锚杆的承压锚固段最短,单位承压锚固段长度分担荷载最高;锚杆破坏时,TC12-3、TC11-1、TC21-1锚杆的受拉承载系数分别为0.398,0.470,0.600;且TC11-1锚杆表现为承压锚固段与受拉锚固段同时破坏,TC12-3、TC21-1锚杆表现为先后破坏;拉压复合型锚杆锚固性能显著提高主要是由于荷载分解作用,界面剪应力双向传递机制及短锚承载效应;从荷载位移曲线来看,拉压复合型锚杆具有较好的抗变形能力,在岩土锚固工程中,具有显著的优势和广阔的应用前景。 相似文献