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11.
Hyun Kyu Suh 《Fuel》2008,87(6):925-932
This paper investigates the effect of injection parameters on the characteristics of dimethyl ether (DME) as an alternative fuel in a diesel engine with experimental and analytical models based on empirical equations. In order to study macroscopic and microscopic characteristics of DME fuel, this work focuses on the atomization characteristics of DME and compares experimental and predicted results for spray development obtained by empirical models for diesel and DME fuel. Detailed comparisons of spray tip penetration from three different empirical correlations and from visualization experiments of diesel and DME fuels were conducted under various fuel injection conditions. In comparison with the results of different empirical equations for measured spray tip penetration, the experimental results of this study provide good agreement with the calculation results based on empirical equations, except during the earliest stage of the injected spray sequence. The results of atomization characteristics indicate that DME showed better spray characteristics than conventional diesel fuel. Also, the fuel injection delay and maximum injection rate of DME fuel are shorter and lower than those of diesel fuel at the same injection conditions, respectively. 相似文献
12.
Integrated Microfluidic CustomArray Device for Bacterial Genotyping and Identification 总被引:2,自引:0,他引:2
13.
N. Z. Mehdizadeh M. Lamontagne C. Moreau S. Chandra J. Mostaghimi 《Journal of Thermal Spray Technology》2005,14(3):354-361
Plasma-sprayed molten molybdenum particles (∼40 μm in diameter) were photographed impinging at high velocity (∼140 m/s) on
a glass substrate at room temperature. An optical sensor detected thermal radiation emitted by a droplet as it approached
the substrate and activated a time delay unit. After a selected time interval, an Nd:YAG laser was triggered, emitting a 5
ns pulse that provided illumination for a charge-coupled device (CCD) camera to photograph the impacting droplet through a
long-range microscope. By varying the delay before pulsing the laser, different stages of droplet deformation were recorded.
Impacting droplets spread into a thin circular film that ruptured and broke into small fragments. An optical detector recording
thermal radiation from the impacting droplet gave a signal that increased as the droplet spread out, reached a maximum when
the liquid film began to rupture, and decreased as portions of the droplet recoiled because of surface tension and then flew
out of view of the photodetector. 相似文献
14.
基于单元变形的思路,由单元守恒方程出发,建立电场中液滴变形的数值计算模型. 在此基础上,将该模型与偶极模型相耦合,提出液滴聚结的计算方法. 由所建模型及计算方法,编制数值计算程序对几种参数下液滴的变形及聚结进行模拟计算. 结果表明,所建模型对液滴变形的预测与实验结果相符较好,对液滴聚结过程的模拟与实验结果大致相符,预测的聚结时间稍低于实验值. 如果进一步提高单元阻力的模化精度及单元离散精度,所建模型会有较好的适用性. 所建模型可实现对液滴的扁平形变形的预测. 研究结果对液滴电变形的理论分析及数值模拟具有一定的借鉴意义. 相似文献
15.
Ebony A. Monson Donna R. Whelan Karla J. Helbig 《International journal of molecular sciences》2021,22(9)
Lipid droplets (LDs) have traditionally been thought of as solely lipid storage compartments for cells; however, in the last decade, they have emerged as critical organelles in health and disease. LDs are highly dynamic within cells, and their movement is critical in organelle–organelle interactions. Their dynamics are known to change during cellular stress or nutrient deprivation; however, their movement during pathogen infections, especially at very early timepoints, is under-researched. This study aimed to track LD dynamics in vitro, in an astrocytic model of infection. Cells were either stimulated with a dsRNA viral mimic, poly I:C, or infected with the RNA virus, Zika virus. Individual LDs within infected cells were analysed to determine displacement and speed, and average LD characteristics for multiple individual cells calculated. Both LD displacement and mean speed were significantly enhanced in stimulated cells over a time course of infection with an increase seen as early as 2 h post-infection. With the emerging role for LDs during innate host responses, understanding their dynamics is critical to elucidate how these organelles influence the outcome of viral infection. 相似文献
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Liquid—liquid thermally induced phase separation of the polymer—diluent system isotactic poly(propylene)—diphenyl ether was studied under an optical microscope. It was found that as the system phase separated, droplets of a diluent-rich phase formed within a polymer-rich matrix. These droplets grew in size and decreased in number by a process known as coarsening. The scaling exponent relating droplet diameter and time was determined. The scaling exponent was found to be a strong function of the droplet phase volume fraction, and this strong dependence on volume fraction was relatively insensitive to temperature. The influence of the ratio of interfacial tension between the phases and the viscosity of the matrix phase was less significant on the growth rate of the droplets. 相似文献
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Emulsions of silicone oil-in water were formed using a Brinkmann Polytron homogenizer with Igepal CO-530 as an emulsifier. Silicone viscosities ranged from 10 to 33,000 mPa.s at 25°C. Rheological characteristics and particle size analyses of silicone oil-in-water emulsions were studied. At high volume fraction of the dispersed phase (70%-75%), silicone oil-in-water emulsions were stable. At lower volume fractions (50%-60%), emulsions formed were less stable and the two phases easily separated in a few days. The emulsions formed with high volume fraction silicone oil show highly non-Newtonian behavior (shear thinning). Emulsions made with low viscosity oils had lower viscosities than those made from high viscosity oils. Relative viscosity-concentration data could be correlated by the Frankel and Acrivos Equation. Increasing the emulsifier concentration of 70% oil-in-water emulsions resulted in a decrease in mean droplet size and an increase in emulsion viscosity. Increasing the intensity of agitation also resulted in higher viscosity and smaller droplet size until a critical energy input above which droplet size increased. Emulsification with low shear mixing provides more control in decreasing mean droplet size with time. 相似文献