柴油-生物柴油-乙醇溶解性及其调和燃料特性的研究

以自制的生物柴油为助溶剂,研究了生物柴油对乙醇和柴油调和燃料的助溶作用;研究了不同比例的柴油-生物柴油-乙醇调和燃料的理化特性及稳定性。结果表明,当生物柴油含量为12.55%时,柴油和燃料乙醇可以以任意比例互溶;乙醇含量过高会导致燃料的各种理化性能下降;乙醇含量为10%,生物柴油含量>12.55%为混合燃料较为适宜的调和比列。     

一种乙醇柴油的微乳化性能研究

针对乙醇与柴油互溶性差的特点,采用添加表面活性剂脂肪醇聚氧乙烯醚（AEO3）和助溶剂正戊醇的方法,改变乙醇柴油的微乳化性能。并通过实验考察了它们的最佳复配比,通过乙醇、柴油、稳定剂体系的拟三元相图,考察了温度对其稳定性的影响。最后对乙醇柴油的主要物性进行了测定。通过一系列实验得知,醇类可以作为乙醇柴油混合燃料的助溶剂,正戊醇的助溶效果相对较好;随着温度的降低,乙醇柴油的微乳化液会逐渐变浑浊,最终会分离;乙醇、助溶剂和表面活性剂的加入会降低乙醇柴油的闪点;表面活性剂AEO3作为乳化剂,在醇类稳定剂助溶下（例如AEO3：正戊醇=1：4）制成的乙醇柴油微乳液,稳定时间可达二个月以上。     

生物柴油特性及作为混合燃料添加剂的研究

论述了生物柴油优越的理化特性,可作为柴油的替代燃料,并讨论了生物柴油作为乙醇（甲醇）与柴油或汽油混合燃料的添加剂情况.通过溶解度测定及三相图实验数据表明生物柴油作为乙醇与柴油添加剂,促溶效果较好;对于生物柴油-汽油-乙醇体系来讲,三者可以任意比例混合,可改善汽油的燃烧性能;对于生物柴油-柴油-甲醇体系,效果不理想.     

生物柴油特性及作为混合燃料添加剂的研究

本文论述了生物柴油优越的理化特性可作为柴油的替代燃料，并讨论了生物柴油作为乙醇(甲醇)与柴油或汽油混合燃料的添加剂情况，通过溶解度测定及三相图实验数据表明：生物柴油作为乙醇与柴油添加剂，促溶效果较好：对于生物柴油-汽油-乙醇体系来讲，三者可以任意比例混合，可改善汽油的燃烧性能：对于生物柴油-柴油-甲醇体系，效果不理想。     

乙醇柴油燃料的研究进展

根据乙醇与柴油的理化性质论述了乙醇作为柴油代用燃料的特点,介绍了乙醇在柴油机中的燃烧方式和节能、环保机理,综述了国内外乙醇柴油燃料的研究进展,最后总结了应用乙醇柴油燃料的意义。     

浅谈乙醇-柴油-汽油混合燃料在柴油机上的应用

在我国大范围推广使用乙醇汽油的十多年来,不仅在很大程度上实现了柴油机的节能降耗,同时也直接推动着我国燃料乙醇生产。但在实际使用过程中,人们也发现乙醇同柴油之间还存在着明显的性能差异,对其在柴油机上的使用产生了相应不良影响。为此,有研究人员尝试通过使用乙醇-柴油-汽油混合燃料以有效解决这一问题。本文将在此基础上,通过对乙醇-柴油-汽油混合燃料的具体特性以及制备进行简单介绍,结合相关研究文献对其在柴油机上的应用以及对柴油机性能的具体影响进行分析研究。     

乳化柴油研究及其应用进展

介绍了乳化柴油的节能降污机理,阐述了乳化剂的选择和用量、极性物、掺水率和乳化设备对柴油乳液的影响,对乳化柴油的稳定性、燃烧性能、腐蚀性、节能和环保等性质在应用中的发展进行了概述．认为通过添加少量有机极性物(如乙醇)制成微乳液可以改善乳液的稳定性、降低乳液黏度以改善其燃烧性能。并对乳化柴油的发展趋势进行了展望,指出生物微乳化柴油是今后乳化柴油发展的一个重要方向。     

乙醇柴油燃料的研究进展

与传统柴油相比较,乙醇柴油因具有成本低,排放污染少等优点,成为当前柴油替代燃料的研究热点.文章分别论述了我国在乙醇和柴油的互溶性、助溶剂、乳化以及微乳化等方面的研究进展和存在的问题,最后,指出了我国乙醇柴油的主要研究方向.     

新型乙醇-柴油混合燃料研究

采用价格低廉的工业乙醇和0~#柴油为原料,在改变温度和工业乙醇与0~#柴油的配比的情况下,对乙醇-柴油的助溶剂选择和混合燃料的质量焓进行了研究。结果表明,从降低成本方面考虑,使用乙基叔丁基醚作为助溶剂优化配方为:0~#柴油、工业乙醇、乙基叔丁基醚的质量分数分别为65.1%、16.3%、18.6%;使用正丁醇作为助溶剂时工业乙醇在乳化柴油中所占的比例最大,相应的优化配方为:0~#柴油、工业乙醇、正丁醇的质量分数分别为71.2%、17.8%、11.0%;混合燃料的质量焓与0~#柴油接近,保持澄清透明状态的稳定时间可达30 d以上。     

柴油与工业醇的互溶性研究

由于甲醇、乙醇的强极性与柴油的非极性差异,使得柴油掺醇量非常有限;且一般含醇柴油燃料都使用高纯度的甲醇和乙醇,必然提高混合燃料的成本.研究了在室温条件下通过不同助溶剂的作用,柴油与工业甲醇或工业乙醇的互溶性.结果表明,柴油和工业级低碳醇可通过助溶剂形成稳定时间超过一个月、经济效益良好的混合燃料,其中,工业甲醇、工业乙醇在混合燃料中的最大质量分数分别为17.7%、18.3%.     

Phase stability,fuel properties,and diesel engine performance of palm-oil-based microemulsion biofuels

Microemulsification and blending are two viscosity-modifying techniques of vegetable oils for direct use with diesel engine. In this study, alcohol blends are mixtures of ethanol, diesel, and palm-oil biodiesel while microemulsion biofuels are thermodynamically stable, clear, and single-phase mixtures of diesel, palm oil, and ethanol stabilized by surfactants and cosurfactants. Although there are many studies on biofuels lately, there is limited research on using biodiesel as a surfactant in microemulsion formulations and applied on engine performance at different engine loads. Therefore, the objectives are to investigate phase stability and fuel properties of formulated biofuels (various blends and microemulsions), to determine the engine performance at different engine loads (no load, and from 0.5 to 2.0 kW), and to estimate laboratory-scale cost of the selected biofuels compared to diesel and biodiesel. The results showed that phase stability and fuel properties of selected microemulsion biofuels are comparable to diesel and biodiesel. These microemulsion biofuels can be applied to the diesel engine at different loads while diesel-ethanol blends and palm-oil-biodiesel-ethanol blends cannot be. It was found that the energy efficiencies of the system using microemulsion biofuels were slightly lower than the average energy efficiency of diesel engine. From this study, it can be summarized that microemulsion biofuels can be formulated using palm-oil biodiesel (palm-oil methyl ester) as a bio-based surfactant and they can be considered as environmentally-friendly alternatives to diesel and biodiesel. However, cost considerations showed that the raw materials should be locally available to reduce additional costs of microemulsion biofuels.     

Influence of two-stage injection and exhaust gas recirculation on the emissions reduction in an ethanol-blended diesel-fueled four-cylinder diesel engine

The purpose of this study is to investigate the effects of two-stage injection and exhaust gas recirculation (EGR) on the spray behavior and exhaust emission characteristics in diesel-ethanol fuel blends fueled four-cylinder diesel engine. The spray behavior is analyzed from the spray development process, spray tip penetration, and spray cone angle, which are obtained from the spray images. The combustion and exhaust emission characteristics are measured from the four-cylinder diesel engine with a common-rail injection system.The experimental results revealed that the increase of the pilot injection amount causes the fast development of the injected pilot spray, and the penetration difference among the main sprays is less than that among the pilot sprays. An increase in the ethanol blending ratio causes an increase in the ignition delay in the pilot combustion, but the main combustion is little influenced by the ethanol blending. The increase in the pilot injection amount shows the reduction effects of NO_x emissions when the pilot injection timing is advanced beyond BTDC 20°. The concentration of soot emissions shows a decreasing pattern according to the advance of the pilot injection and the decrease in the pilot injection amount. The CO emissions increase with the advance of the pilot injection timing, the increase in the pilot injection amount, and the ethanol blending ratio. In addition, the increase in the ethanol blending ratio and the advance of the pilot injection timing induce an increase in the HC emissions. The increase in the pilot injection amount induces a slight increase in the HC emissions.     

聚合物拉伸过程中颈缩行为的研究进展

综述了聚合物拉伸过程中的颈缩行为,并从研究颈缩行为的一般内容、颈缩不稳定动力学以及本构理论等方面对颈缩行为的发展历史进行了全面的阐述,最后,探讨了聚合物拉伸过程中颈缩行为的抑制,对未来的研究方向提出了有益的见解。     

Influence of temperature on the flow properties of bulk solids

The flow behaviour of bulk solids depends upon a number of parameters. Shear tests are often used to determine the flow behaviour at room temperature. This paper aims to look at the influence of temperature on the flow behaviour of bulk solids. A newly developed ring shear test shows that the flow behaviour of some specific bulk solids depends upon the temperature.     

Periodic behaviour of a class of unstructured kinetic models for continuous bioreactors

The periodic behaviour of a large dass of unstructured kinetic models for continuous bioreactors is analyzed using elementary concepts of singularity theory and continuation techniques. The class consists of models for which the utilization rate of the limiting substrate is linearly related to the rates of cell growth and product formation. The model kinetics are allowed, on the other hand, to depend on substrate, biomass and product. The stability analysis allows the derivation of general analytical conditions for the occurrence of periodic behaviour in these models. It is shown that for a number of important cases, the occurrence of oscillatory behaviour is conditioned mainly by the kinetics of product formation. The singularity theory also allows the construction of a useful picture in the multidimensional parameter space delineating the different behaviour these models can predict including bistability and stable oscillatory behaviour.     

Effect of filler–filler interaction on rheological behaviour of natural rubber compounds filled with both carbon black and silica

Rubber compounds are reinforced with fillers such as carbon black and silica. In general, filled rubber compounds show smooth rheological behaviour in measurement of Mooney viscosity or Mooney scorch time. Variation in rheological behaviour was studied in terms of the filler composition using natural rubber compounds filled with both carbon black and silica (carbon black/silica = 60/20,40/40, and 20/60 phr). The compound filled with carbon black/silica of 60/20 phr showed normal rheological behaviour. However, the compounds filled with carbon black/silica of 40/40 and 20/60 phr showed abnormal rheological behaviour, in which the viscosity increased suddenly and then decreased at a certain point during the measurement. The abnormal behaviour was explained by the strong filler–filler interaction of silica. Moreover, the abnormal rheological behaviour was displayed more clearly as the storage time of compounds is increased. © 2003 Society of Chemical Industry     

Characterization and modelling of the viscous behaviour of adhesives using the modified Arcan device

The non-linear behaviour of an epoxy adhesive has been studied thanks to the use of a modified Arcan test device. Multilevel creep tests have been performed in order to characterize the time-dependent behaviour. A visco-elastic model has been chosen to describe the behaviour of the adhesive. This model is based on the decomposition of the visco-elastic strain into elementary viscous mechanisms. The non-linear behaviour of the visco-elasticity is taken into account thanks to a non-linear function which depends on the stress. A specific identification procedure based on a single test has been proposed. Finally, the model has been validated using tests that have not been used for the identification. The model proposed in this paper enables the time-dependent non-linear behaviour of adhesives to be reproduced in a correct manner.     

On the observation of inductive high-frequency impedance behaviour during the electrodeposition of Au—Sn alloys

Inductive high-frequency impedance behaviour is often observed in metal electrodeposition systems. This behaviour is typically attributed to equipment limitations or non-idealities in the cell set-up and electrical connections. Such instrumental artefacts would nevertheless be relevant to a frequency range which is expected to be well above that in which inductive behaviour is in fact observed (down to a few tens of Hz). In this paper some results on an acidic Au—Sn electrodeposition system are reported. Electrochemical impedance and potentiostatic transients were measured. These results suggest that the high-frequency inductive behaviour may be related to metal nucleation processes. A correlation is proposed between the pseudo-inductive potentiostatic nucleation transients and the pseudo-inductive behaviour of the impedance spectra.     

Viscous and elastic behaviour of SEBS triblock copolymer

The viscous and elastic behaviour of the saturated triblock copolymer polystyrene-block-poly(ethylene-co-butylene)-polystyrene (SEBS) was investigated using a capillary viscometer. The viscous behaviour was evaluated from the variation of viscosity with shear and temperature, and the elastic behaviour from the capillary entrance pressure loss, die swell ratio and surface roughness. The melt behaviour was found to result from the two-phase structure which existed up to a particular shear and/or temperature and thereafter from the single-phase structure.     

Numerical modelling of the quasi-brittle behaviour of refractory ceramics by considering microcracks effect

In the steelmaking industry, the inner lining of ladles is made of refractory ceramics, which are constantly subjected to thermal shocks during their service. Experimentally, it is observed that pre-existing microcracks could significantly increase the thermal shock resistance of these ceramics. The presence of such microcracks network within the refractory microstructure could lead to a non-linear quasi-brittle mechanical behaviour.To model this quasi-brittle behaviour, a suitable numerical approach is the Discrete Element Method (DEM), which can circumvent the limitations of more conventional continuum approaches in capturing microstructural effects required to simulate multi-fracture propagation.Here, it is aimed to simulate such quasi-brittle behaviour by initial well-distributed damages, with a strength dispersion following a Weibull distribution. In this way, the microcracks effect on the quasi-brittle behaviour of a numerical sample under uniaxial and cyclic tensile tests is investigated. Ultimately, a quantitative DEM model to simulate such a complex behaviour is proposed.