Properties of palm-oil-in-water emulsions: Effect of mixed emulsifiers

Palm-oil-in-water emulsions were prepared with mixtures of Tween 40 and Span 40 in various proportions. Stability and droplet-size distribution of the emulsions were monitored. Interfacial tensions of the palm oil/water interface were also determined in the presence of these emulsifier mixtures. Emulsifying efficiency of the emulsifier mixtures was assessed. No synergistic effect of Tween 40 (sorbitan monopalmitate with 18–22 moles of ethylene oxide) and Span 40 (sorbitan monopalmitate) was found on interfacial tension. Tween 40 alone (hydrophilic-lipophilic balance value 15.6) at 1.0% w/w gave palm oil emulsions that were stable for more than 30 d at 60°C. Emulsifier mixtures of Tween 40 and Span 40 with hydrophilic-lipophilic balance values in the range of 8.0–8.6 produced stable emulsions only at much higher emulsifier-mixture concentrations. The inherent nature of the oil and the accompanying natural surface-active materials present in the oil can influence the prevailing conditions at the oil/water interface and alter composition of the interfacial film and hence its stability.     

多菌灵·硫·三环唑混配对抑制水稻稻瘟病菌和纹枯病菌的协同增效作用

多菌灵、硫及三环唑混配成悬浮剂,对抑制稻瘟病菌的菌丝生长、分生孢子萌发、附着胞的形成、产孢能力及纹枯病菌菌丝生长等都具有较明显的协同增效作用,协同作用比率(SR)分别为1.64、5.58、4.30、1.81及1.73。混配剂集合了多菌灵、硫及三环唑的优点,并显示出耐雨水冲刷、持效期长的特点。田间试验亦表明其防病增产作用比较显著。     

混炼硅橡胶的配合技术(一)

介绍了混炼硅橡胶的基本配合过程和硫化体系,着重比较了间歇法和连续法两种混炼工艺的生产效率及对硅橡胶硫化胶性能的影响,讨论了6种过氧化物硫化剂的特点及适应范围。     

SBS环保耐热型装饰胶粘剂的研制

采用SBS弹性体、增粘树脂、增强剂及按一定比例配合而成的混合溶剂,制备了一种价廉物美的新型环保型胶粘剂。讨论了混合溶剂的(δ+γ)值、星型SBS与线型SBS的质量比、增强剂对胶粘剂性能的影响。结果表明:不管在高温还是在常温下,加入了增强剂的试样的剪切强度都优于市场上出售的胶粘剂。     

能效优先的用户关联与功率控制协同优化机制

在异构蜂窝网络中,针对系统的能效,提出了一种基于效用函数最大化模型的用户关联与功率控制协同优化方案,该方案表示为非线性混合整数问题。为了求得该问题的最优解,设计了一种迭代算法,首先将原问题转换为带参数的多项式形式的问题,在外层循环利用Dinkelbach方法求得最佳的能效因子,然后在内层循环分别求得最佳的用户关联矩阵和传输功率。最终实验结果表明,用户关联与功率控制协同的优化方案在能效和负载平衡方面比固定功率条件下的用户关联策略的性能更优。     

Assessment of Bitumen Re c overy from the Athabasca Oil Sands Using a Laboratory Denver Flotation Cell

A methodology was developed in this study to evaluate the effect of operating parameters on the processability of oil sands using small‐scale laboratory experimental devices. By subtracting bitumen recovered to the froth by entrainment with water, the concept of “true flotation recovery” is proposed to describe bitumen recovery resulting from bitumenbubble attachment. The experimental results indicated that “true flotation recovery” is a more sensitive and meaningful marker than overall bitumen recovery to evaluate the processability of oil sands using small‐scale laboratory test units.     

火焰光度法测定氧化铝中的氧化钠

氧化铝原料纯度高,熔点高,不被氢氟酸—硫酸所分解,但能迅速熔解于热的硫—磷混酸溶液中。控制溶液中硫—磷混酸的浓度,并在氧化钠系列标准溶液中配入等量的硫—磷混酸,即可在火焰光度计上直接测量氧化钠的含量。     

Performance of solvothermally prepared Ga2O3-Al2O3 catalysts for SCR of NO with methane

The solvothermal reaction of mixtures of aluminum isopropoxide (AIP) and gallium acetylacetonate (Ga(acac)₃) directly yielded the mixed oxides of γ-Ga₂O₃-Al₂O₃. In the solvothermal synthesis, the crystal structure of mixed oxides was controlled by the initial formation of γ-Ga₂O₃ nuclei. The mixed oxides prepared in diethylenetriamine have extremely high activities for selective catalytic reduction (SCR) of NO with methane as a reducing agent. With increasing crystallite size of the spinel structure, the catalytic activity increased. The ratio of the amount of methane consumed by combustion to total methane conversion was proportional to the density of acid sites on the surface of the mixed oxides. The mixed oxide catalysts prepared in diethylenetriamine had lower densities of acid sites and showed a higher methane-efficiency for CH₄-SCR than those prepared in other solvents. These catalysts maintained their high activity even when the reaction was carried out under the severe conditions (i.e., high space velocity and low NO concentration).     

Mixed H2/H∞ robust model predictive control with saturated inputs

In this paper, we investigate the mixed H₂/H_∞ robust model predictive control (RMPC) for polytopic uncertain systems, which refers to the infinite horizon optimal guaranteed cost control (OGCC). To fully use the capability of actuators, we adopt a saturating feedback control law as the control strategy of RMPC. As the saturating feedback control law can be effectively represented by the convex hull of a group of auxiliary linear feedback laws, the auxiliary feedback laws allow us to design the actual feedback control law without consideration of the input constraints directly to achieve the improved performance. Moreover, we suggest the relative weights on the actual and auxiliary feedback laws to the RMPC, which in turn improves the closed-loop system performance. Furthermore, an off-line design of the proposed RMPC is also developed to make it more practical. Numerical studies demonstrate the effectiveness of the proposed algorithm.     

Mixed monolayer and mixed micelle formation in binary mixture of surfactants—Systems for trioxyethylenated dodecyl sulfonate and some polyoxyethylenated fatty alcohol ether nonionic surfactants

The interaction and synergism of some polyoxyethylenated fatty alcohol ether (POE) nonionic surfactants (C₁₂E₂, C₁₂E₃, C₁₀E₅, C₁₀E₇, where C_x indicates number of carbon atoms in the chain and E_y indicates number of oxyethylene glycol ethers) with trioxyethylenated dodecyl sulfonate (C₁₂E₃S) in mixed monolayer formation at the surface and in mixed micelle formation in aqueous solutions were studied at 25 and 40°C by calculating interaction parameters (β_α, β_M) from surface tension-concentration data by use of Rosen's equations based on the nonideal solution theory. All the systems investigated adapt reasonably well to the nonideal model, with negative values of β_σ and β_M (where M means micelle and σ refers to the air-liquid interface) indicating a favorable interaction between the mixed surfactants. Either at a monolayer or in a mixed micelle, the attractive interaction becomes stronger when the alkyl chain in the POE surfactant is longer, i.e., when the POE becomes more hydrophobic. The interaction increases in the order C₁₀E₇<C₁₀E₅<C₁₂E₃, C₁₂E₂. For the two C₁₀E _n (n= 5,7)/C₁₂E₃S systems, as temperature increases from 25 to 40°C, the interaction increases in a mixed micelle, but it decreases in a mixed monolayer. Synergism in mixed micelle formation exists for C₁₂E₃S/C₁₀E _n mixtures when X₁ ^M , the mole fraction of POE in a mixed micelle, is ≈0.4–0.8, whereas synergism does not occur in the systems of C₁₂E₃S/C₁₂E _m due to the large difference between CMC₁ and CMC₂, i.e., large |In(C ₁ ^M /C ₂ ^M )| value (where CMC=critical micelle concentration). The degree of synergism in mixed micelle formation is temperature independent and is 0.23, 0.18, and close to zero for C₁₀E₅/C₁₂E₃S, C₁₀E₇/C₁₂E₃S, and C₁₂E _m (m=2,3)/C₁₂E₃S systems, respectively. Synergism in surface tension reduction effectiveness occurs in C₁₂E₃S/C₁₂E₂ and C₁₂E₃S/C₁₂E₃ systems. The mole fractions of POE in the solution phase are 0.302 and 0.333 for the two mixtures at the point of maximum synergism.