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61.
Synthesis and performances for treating oily wastewater produced from polymer flooding of new demulsifiers based on polyoxyalkylated N,N‐dimethylethanolamine 下载免费PDF全文
Usually, oily wastewater produced from polymer flooding (OWPF) was treated by cationic polymer in oilfield. In this paper, six block copolymers of ethylene oxide and propylene oxide were prepared by using N,N‐dimethylethanolamine (DMEA) as the acceptor (DMEA‐mnp and DMEA‐mnpq, n:m:p:q represented the weight ratio of different blocks). Most of DMEA products could perform well for treating OWPF, especially DMEA1231. Their performances were mainly affected by temperature. The reason of increasing oil removal performance of DMEA1231 with temperature was the decrease of interfacial dilational modulus (ε) with increasing temperature. When temperature raised up to 55°C, the ε of DMEA1231 had the minimum (1.5 l mN/m). Therefore, the OiW had the minimum (90 mg/l). Because DMEA1231 had the best performance, its flocculation kinetics was studied systemically. The results showed that the optimum condition for DMEA1231 was as follows: dosage was 300 mg/l, temperature was 55°C, stirring speed was 200 rpm and stirring time was 5 min. At last, the offshore oil field test was carried out to check the DMEA1231 performance. The result showed that at the optimum condition, DMEA1231 could perform as well as the cationic polymer. The most important thing was that flocs of DMEA1231 were not viscous and floated on the surface of the water. The results obtained by this paper provide a good choice for the treatment of OWPF in offshore oilfield to avoid the formation of viscous flocs. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Molecular dynamics (MD) simulations using Morse interaction potential are performed in studies of [110] symmetrical tilt grain
boundary (GB) structures with mis-orientation angles 50.5°(Σ11), 129.5°(Σ11), 70.5°(Σ3) and 109.5°(Σ3) at various tempratures.
The GB structures are found to start local disordering at about 0.5T
m
(T
m
is the melting point of aluminium) for 50.5°(Σ11), 0.32T
m
for 129.5° (Σ11) and 0.38T
m
for 70.5°(Σ3), respectively. These results agree with conclusions deduced from the anelastic measurements. But, for twin-boundary
structure 109.5°(Σ3), this disordering has not been found even when temperature increases up to 0.9T
m
.
The project supported by the National Natural Science Foundation of China and Laboratory for Non-linear Mechanics of Continuous
Media, Institute of Mechanics, Academia Sinica. 相似文献
65.
A simple method is developed for predicting the fracture behaviour of struetures made of quasi-brittle materials sueh as eonerete and roek using the data from laboratory-sized speeimens. The method is based on the reeently-developed boundary effeet concept and associated asymptotic model. It is demonstrated that the "apparent" size dependence of fraeture behaviour of concrete and rock is in fact due to the influence of specimen boundaries. Various size effect phenomena that are often observed in fracture meehanies tests of eoncrete and roek are related to each other, and the asymptotie boundary effect model can explain all the observed "size" effeet phenomena. Four types of experimental results available in the literature (ineluding the data measured on (1) the speeimens of identical size with different crack-to-size (α) ratios, (2) specimens of different sizes with different a-ratios, (3) different types of specimens and (4) geometrieally similar speeimens) are used to verify the asymptotic boundary effect model, and it is found that the predictions of the model agree very well with the experimental results. Furthermore, the important fracture properties, fracture toughness KIC and strength f, of quasi-brittle materials sueh as eonerete and roek can also be calculated using the formulae provided in the model. 相似文献
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Hong Zhu * Patrick Phelan Tianhua Duan Gregory Raupp H. J. S. Fernando Beijing Institute of Microbiology Epidemiology Beijing P. R. China Department of Mechanical Aerospace Engineering Arizona State University Tempe Department of Chemical Materials Engineering Arizona State University Tempe *Author to whom correspondence should be addressed. Tel: -- E-mail: zhuhong@hotmail.com 《中国颗粒学报》2003,1(3):119-123
1.IntroductionBioaerosolsaremicroorganismsorparticles,gases,vapors,orfragmentsofbiologicalorigin(i.e.,aliveorreleasedfromalivingorganism)thatexistintheair.Bioaerosolsareeverywhereintheenvironment.Underfavorableconditions,bioaerosolsareabletogrowandpropagateonavarietyofbuildingmaterialsandindoorsurfaces,causingindoorairpollution.Therefore,owingtotheirubiquitouspresenceinnature,bioaerosolsasapollutionsourcearealmostinevitableinarangeofenclosedenvironmentsandincommunityair(Kodama&McGee,1986;Lig… 相似文献
68.
针对进化或拓扑优化方法的不足,提出了一种基于遗传算法的新型进化式拓扑优化方法--三角网格进化法,该方法不仅能够同时进行拓扑,形状与截面变量优化设计,而且在优化过程中实现了退化和进化的统一,提高了优化效率。另外本文还首次对结构类型变量进行了优化计算,取得了有益的结果。最后几个数值算例证明了本方法的可行性和有效性。 相似文献
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Xiangyu Cui Li Duan Jiaan Yan 《The Journal of the Operational Research Society》2015,66(10):1646-1655
Investigating the inverse problem of the classical Markowitz mean-variance formulation: Given a mean-variance pair, find initial investment levels and their corresponding portfolio policies such that the given mean-variance pair can be realized, we reveal that any mean-variance pair inside the reachable region can be achieved by multiple portfolio policies associated with different initial investment levels. Therefore, in the mean-variance world for a market of all risky assets, the common belief of monotonicity: ‘The larger you invest, the larger expected future wealth you can expect for a given risk (variance) level’ does not hold, which stimulates us to extend the classical two-objective mean-variance framework to an expanded three-objective framework: to maximize the mean and minimize the variance of the final wealth as well as to minimize the initial investment level. As a result, we eliminate from the policy candidate list the set of pseudo efficient policies that are efficient in the original mean-variance space, but inefficient in this newly introduced three-dimensional objective space. 相似文献