Contribution to the Study of the Flow of Viscous Liquids

In (general) elastico-viscous liquids the response to stress at any instant will depend on previous rheological history, the equations of state needed to describe the rheological properties of a typical material element at any instant t being expressible in the form of a (properly invariant†) set of integro-differential equations relating its deformation, stress and temperature histories (as defined by a metric tensor (of a convected frame of reference), a stress tensor and the temperature measured in the element as functions of previous time t'( < t)) together with the time lag (t – t') and physical constant tensors associated with the element (1). Thus in any type of oscillatory motion a rheological history will necessarily be a function of the frequency of the forcing agent, the rheological history of a number of different types of elastico-viscous liquids in some simple shearing oscillatory flows being a rather simple oscillatory history (see, for example, (2–4)). It is, therefore, to be expected that a liquid with elastic properties will behave somewhat differently from any inelastic viscous liquid when subjected to any kind of oscillatory motion, and it is for this reason that oscillatory motions have been used extensively to detect and measure the elastic properties of liquids (see, for example, (2–5)).

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A Pipe-Line Temperature Probe for Viscous Liquids and Powders

Measurement and Control ◽

10.1177/002029408401700103 ◽

1984 ◽

Vol 17 (1) ◽

pp. 21-23

Author(s):

B. W. Ramsay ◽

H. A. Slight

Keyword(s):

Viscous Liquids ◽

Temperature Probe ◽

Pipe Line ◽

Line Temperature

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Cavity optomechanics on a microfluidic resonator with water and viscous liquids

Light Science & Applications ◽

10.1038/lsa.2013.66 ◽

2013 ◽

Vol 2 (11) ◽

pp. e110-e110 ◽

Cited By ~ 70

Author(s):

Kyu Hyun Kim ◽

Gaurav Bahl ◽

Wonsuk Lee ◽

Jing Liu ◽

Matthew Tomes ◽

...

Keyword(s):

Cavity Optomechanics ◽

Viscous Liquids

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Discrimination of ablation, shielding, and interface layer effects on the steady-state formation of persistent bubbles under liquid flow conditions during laser synthesis of colloids

Journal of Flow Chemistry ◽

10.1007/s41981-021-00144-7 ◽

2021 ◽

Author(s):

Mark-Robert Kalus ◽

Riskyanti Lanyumba ◽

Stephan Barcikowski ◽

Bilal Gökce

Keyword(s):

Steady State ◽

Laser Ablation ◽

Liquid Flow ◽

Production Efficiency ◽

Synthesis Method ◽

Target Surface ◽

Interface Layer ◽

Nanosecond Laser ◽

Viscous Liquids ◽

Shielding Effects

AbstractOver the past decade, laser ablation in liquids (LAL) was established as an innovative nanoparticle synthesis method obeying the principles of green chemistry. While one of the main advantages of this method is the absence of stabilizers leading to nanoparticles with “clean” ligand-free surfaces, its main disadvantage is the comparably low nanoparticle production efficiency dampening the sustainability of the method and preventing the use of laser-synthesized nanoparticles in applications that require high amounts of material. In this study, the effects of productivity-dampening entities that become particularly relevant for LAL with high repetition rate lasers, i.e., persistent bubbles or colloidal nanoparticles (NPs), on the synthesis of colloidal gold nanoparticles in different solvents are studied. Especially under batch ablation conditions in highly viscous liquids with prolonged ablation times both shielding entities are closely interconnected and need to be disentangled. By performing liquid flow-assisted nanosecond laser ablation of gold in liquids with different viscosity and nanoparticle or bubble diffusivity, it is shown that a steady-state is reached after a few seconds with fixed individual contributions of bubble- and colloid-induced shielding effects. By analyzing dimensionless numbers (i.e., Axial Peclet, Reynolds, and Schmidt) it is demonstrated how these shielding effects strongly depend on the liquid’s transport properties and the flow-induced formation of an interface layer along the target surface. In highly viscous liquids, the transport of NPs and persistent bubbles within this interface layer is strongly diffusion-controlled. This diffusion-limitation not only affects the agglomeration of the NPs but also leads to high local densities of NPs and bubbles near the target surface, shielding up to 80% of the laser power. Hence, the ablation rate does not only depend on the total amount of shielding matter in the flow channel, but also on the location of the persistent bubbles and NPs. By comparing LAL in different liquids, it is demonstrated that 30 times more gas is produced per ablated amount of substance in acetone and ethylene glycol compared to ablation in water. This finding confirms that chemical effects contribute to the liquid’s decomposition and the ablation yield as well. Furthermore, it is shown that the highest ablation efficiencies and monodisperse qualities are achieved in liquids with the lowest viscosities and gas formation rates at the highest volumetric flow rates.

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Preparation of rigid polyurethane foams using low-emission catalysts derived from metal acetates and ethanolamine

e-Polymers ◽

10.1515/epoly-2016-0021 ◽

2016 ◽

Vol 16 (4) ◽

pp. 265-275 ◽

Cited By ~ 5

Author(s):

Duangruthai Sridaeng ◽

Wannisa Jitaree ◽

Preecha Thiampanya ◽

Nuanphun Chantarasiri

Keyword(s):

Compressive Strength ◽

Catalytic Activity ◽

Rise Time ◽

Polyurethane Foams ◽

Gel Time ◽

Commercial Catalyst ◽

Metal Acetate ◽

Viscous Liquids ◽

Low Emission ◽

Cu And Zn

AbstractTwo metal acetate-ethanolamine complexes, namely Cu(OAc)2(EA) and Zn(OAc)2(EA), were synthesized from metal acetates [M(OAc)2, where M=Cu and Zn] and ethanolamine (EA). These metal acetate-ethanolamine complexes can be used as catalysts in the preparation of rigid polyurethane (RPUR) foams. Both Cu(OAc)2(EA) and Zn(OAc)2(EA) were obtained as viscous liquids, which have very weak odor and could be easily dissolved in the starting materials of RPUR foam formulation. The results were compared with RPUR foam prepared from dimethylcyclohexylamine (DMCHA), which is a commercial catalyst with very strong amine odor. Considering the gel time and rise time, Cu(OAc)2(EA) had higher catalytic activity than Zn(OAc)2(EA) and both metal acetate-ethanolamine complexes had lower catalytic activity than DMCHA. Density and compressive strength of RPUR foam catalyzed by Cu(OAc)2(EA) were comparable to that prepared from DMCHA.

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