A review of microfluidic concepts and applications for atmospheric aerosol science

Microfluidics is used in a broad range of applications, from biology and medicine to chemistry and polymer science, because this versatile platform enables rapid and precise repeatability of measurements and experiments on a relatively low-cost laboratory platform. Despite wide-ranging uses, this powerful research platform remains under-utilized by the atmospheric aerosol science community. This review will summarize selected microfluidic concepts and tools with potential applications to aerosol science. Where appropriate, the basic operating conditions and tunable parameters in microfluidics will be compared to typical aerosol experimental methods. Microfluidics offers a number of advantages over larger-scale experiments; for example, the small volumes of sample required for experiments open a number of avenues for sample collection that are accessible to the aerosol community. Filter extraction, spot sampling, and particle-into-liquid sampling techniques could all be used to capture aerosol samples to supply microfluidic measurements and experiments. Microfluidic concepts, such as device geometries for creating emulsions and developments in particle and droplet manipulation techniques will be reviewed, and current and potential microfluidic applications to aerosol science will be discussed.

Copyright © 2018 American Association for Aerosol Research     

The legacy of John Tyndall in aerosol science

In several respects Tyndall is the founder of applied aerosol science. His research, demonstrations, and lectures profoundly influenced Zsigmondy and the development of the ultramicroscope. This is the tool used by Perrin to experimentally test the theories of Brownian motion of Smoluchowski and Einstein. His speculation on the cause of the color of the sky directly inspired Rayleigh to develop a mathematical theory for light scattering for small particles. This then led to the development of scattering theory by Mie and Debije for micron size particles. Brownian motion and the size-wave length dependence of light, cornerstones of 20th century aerosol science, were direct extensions of Tyndall's study.

The historical role of Tyndall in the use of aerosol to disestablish heterogenesis, in the design of respirators, and in monitoring environmental contamination resonate to the present day. But to emphasize only his work on dark field illumination and the scattering of light by small particles, slights his critical study on radiant heat. The appropriate treatment of absorption and emission of radiant heat where both particles and gasses are present remain an open question to the present.     

Combustion modelling opportunities and challenges for oxy-coal carbon capture technology

Oxy-coal combustion is one of the leading technologies for carbon capture and storage. This paper presents a review of the opportunities and challenges surrounding the development of oxy-coal combustion models and discusses historical and recent advances in specific areas related to computational fluid dynamics (CFD), including char oxidation, radiation, pollutant formation and removal (Hg, NO_x and SO_x), and the impact of turbulence. CFD can be used to assess and optimise full-scale retrofit designs and to provide data on matching air-fired heat duties. In addition, CFD can also be used to improve combustion efficiency and identify potential reductions in corrosion, slagging, fouling and trace pollutant emissions. Transient simulations are becoming more computationally affordable for coal combustion, providing opportunities for model development. High concentrations of CO₂ and H₂O in oxy-coal can influence chemical kinetic rates, burnout and ash properties. The modelling can be improved by incorporating detailed kinetic mechanisms of gasification reactions. In addition, pollutant formation and removal mechanisms must be understood during oxy-coal firing to aid the selection of flue-gas cleaning strategies. Radiative heat transfer using spectral models for gaseous properties may be necessary in oxy-coal modelling because CO₂ and H₂O molecules have strong emission bands. Finally this review provides a coherent near-term and long-term oxy-coal specific CFD sub-models development strategy to simulate the complex oxy-coal combustion processes, heat transfer and pollutant emissions in power generation systems.     

煤化工产业科技发展综述

回顾了新型煤化工技术路线,指出煤制甲醇及下游产品、煤制油、以及以煤气化为龙头的合成氨是我国洁净煤利用技术的主要发展方向。     

The science and technology of hot compaction

The production and properties of single polymer composites is described, where the fibre and matrix phases are of identical chemical composition. The structure of the composites has been explored using mechanical tests, DSC and electron microscopy. Measurements of mechanical anisotropy, thermal expansion and impact behaviour are of especial interest.The commercialisation of the hot compacted materials is also described. Potential applications include the automotive industry, sports protection goods, loudspeaker cones and helicopter radomes.     

Role of in situ generated silica for rubber science and technology

Filled rubbers have a long history in rubber technology. Filler morphology in the rubber matrix significantly influences the performance of filled rubber products. Therefore, we have to achieve a certain morphology of filler in the rubbery matrix in order to enjoy good reinforcement. However, it has not been sufficiently known what kind of morphology is necessary for the reinforcement, because preparations of adequate models for the characterization of filler morphology have been difficult. The in situ silica filling of the rubber matrix can be modeled for the preparations. In this paper, the characteristic features of in situ silica generated in diene rubbers are reviewed, citing recent reports. Two important models are presented. One is a homogeneous silica filling in situ, producing soft rubber nanocomposites. The other is the formation of an in situ silica filler network, creating stiff rubber nanocomposites. The controlled in situ silica filling is useful to evaluate the reinforcement effect of filler in a rubber matrix. © 2016 Society of Chemical Industry     

回眸与展望流态化科学与技术

流态化作为一门具有科学内涵的学科始于20世纪40年代,但对于尚没有流态化命题下应用流态化技术的生活和生产活动,如淘米和扬谷,早已存在。此类活动的文字记载出现于16世纪。近代流态化理论以郭慕孙提出的广义流态化理论和无气泡气固接触理论以及Davidson提出的气泡理论为代表,而近代流态化技术的工业应用则以煤的气化和石油的催化裂化为代表。当前流态化的理论研究主要集中于流化床内由不同尺度的颗粒、液滴、气泡、聚团的时空不均匀分布所形成的不均匀结构的预测与优化调控理论与方法的研究,不均匀结构与传递和反应的关系理论的研究以及流态化床的计算机模拟与放大研究。当前流态化技术的工业应用范围已涵盖化工、冶金、能源、材料、环境等领域。在我国,由于经济快速发展,流态化技术应用尤为活跃。采用由流化床局部构效关系模型与两流体模型相结合的计算机模拟方法是解决流态化反应器过程优化调控和设备放大问题的有效途径。该方法面临许多挑战,需要付出艰苦的努力。目前中国工业正处于调整产业结构,淘汰落后产能,实现节能减排、清洁生产的转型期。在许多工业流程中,用高效节能的流态化床反应器替代低效高能耗的回转窑、固定床、移动床反应器正逢其时。     

Review on the nanoparticle fluidization science and technology

Gas fluidization has an ability to turn static particles to fluid-like dense flow, which allows greatly improved heat transfer among porous powders and highly efficient solid processing to become reality. As the rising star of current scientific research, some nanoparticles can also be fluidized in the form of agglomerates, with sizes ranging from tens to hundreds of microns. Herein, we have reviewed the recent progress on nanomaterial agglomeration and their fluidization behavior, the assisted techniques to enhance the fluidization of nanomaterials, including some mechanical measures, external fields and improved gas injections, as well as their effects on solid fluidization and mixing behaviors. Most of these techniques are effective in breaking large agglomerates and promoting particulate fluidization, meanwhile, the solid mixing is intensified under assisted fluidization. The applications of nanofluidization in nanostructured material production and sustainable chemical industry are further presented. In summary, the fluidization science of multidimensional, multicomponent and multifunctional particles, theirmulti-phase characterization, and the guideline of fluidized bed coupled process are prerequisites for the sustainable development of fluidized bed based materials, energy and chemical industry.