Liquid Droplets (liquid + droplet)

Distribution by Scientific Domains
Distribution within Chemistry


Selected Abstracts


Magnetic Liquid Marbles: Manipulation of Liquid Droplets Using Highly Hydrophobic Fe3O4 Nanoparticles

ADVANCED MATERIALS, Issue 6 2010
Yan Zhao
Magnetic liquid marbles exhibit a remarkable ability to be opened (see image) and closed reversibly under the action of a magnetic field. Liquid can be either extracted from or added to the opened liquid marble simply with a capillary needle. Two opened liquid marbles can also be coalesced into a larger one. The magnetic liquid marbles can be maneuvered two- and three-dimensionally. [source]


Ketoprofen nanoparticle gels formed by evaporative precipitation into aqueous solution

AICHE JOURNAL, Issue 7 2006
Xiaoxia Chen
Abstract Aqueous nanoparticle gels of a poorly-water soluble drug, ketoprofen, were produced by evaporative precipitation into aqueous solution (EPAS). Liquid droplets of surfactant stabilized ketoprofen containing residual solvent were dispersed in water from 60 to 90°C below the melting point of pure ketoprofen. The carboxylic acid group in ketoprofen dissociates in pure water, providing electrostatic stabilization of the droplets to complement steric stabilization. Stable amorphous ketoprofen particles with a mean size of 135 nm, measured by dynamic light scattering, were formed with only 0.1% w/v poloxamer 407, resulting in an exceptionally high drug-to-surfactant ratio of 10:1. For 5% w/v poloxamer 407, interactions with ketoprofen produced a bluish, transparent gel composed of ,50 nm particles. In 2 min, 98% of the ketoprofen in the gel nanoparticles dissolved. The favorable interactions between the ketoprofen and poloxamer 407, along with the electrostatic and steric stabilization, lead to gelation, which further stabilizes the unusually small particles. The rapidly dissolving wet gels with extremely small particle sizes, one month stability, and relatively low viscosities, are of interest in transdermal and parenteral delivery; furthermore, the gels may be dried for oral delivery. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source]


Observations of initiation stage of spontaneous vapor explosions for droplet scale

HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 1 2008
Takeo Takashima
Abstract In this study, the initiation stage of spontaneous vapor explosions generated by single droplets of molten tin submerged in water was investigated using a high- speed video camera operated with a reflected light system. Photographs of the formation process of vapor film, the process of vapor film disturbance, and the initiation process of the vapor explosions for different masses of molten tin and different nozzle diameters were obtained. The results demonstrate that partial thermal interaction between tin and water does not cause a vapor explosion with fragmentation. The vapor film disappears locally during the formation of the vapor film around the hot liquid droplet. Direct contact between the hot molten tin surface and water is thereby generated. However, the local disappearance of the vapor film does not progress and the vapor film is reconstructed. A vapor explosion occurs when the vapor film collapses at the local area of the bottom or edge of the disk-shaped droplet. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(1): 41,55, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20185 [source]


An evaluation of actual and simulated smoke properties

FIRE AND MATERIALS, Issue 2 2005
Jill Suo-Anttila
Abstract Federal regulations require that aircraft cargo compartment smoke detection systems be certified by testing their operation in flight. For safety reasons, only simulated smoke sources are permitted in these certification tests. To provide insight into smoke detection certification in cargo compartments, this research investigates the morphology, transport and optical properties of actual and simulated smoke sources. Experimental data show the morphology of the particulate in smoke from flaming fires is considerably different from simulated smoke. Although the detection of smoldering fires is important as well, only a qualitative assessment and comparison of smoldering sources was possible; therefore, efforts were concentrated on the quantitative comparison of smoke from flaming fires and smoke generators. The particulate for all three different flaming fires was solid with similar morphological properties. Simulated smoke was composed of relatively large liquid droplets, and considerably different size droplets can be produced using a single machine. Transport behavior modeling showed that both the actual and simulated smoke particulates are sufficiently small to follow the overall gas flow. However, actual smoke transport will be buoyancy driven due to the increased temperature, while the simulated smoke temperature is typically low and the release may be momentum driven. The morphology of the actual and simulated smoke were then used to calculate their optical properties. In contrast to the actual smoke from a flaming fire, which is dominated by absorption, all of the extinction for the simulated smoke is due to scattering. This difference could have an impact on detection criteria and hence the alarm time for photoelectic smoke detectors since they alarm based on the scattering properties of the smoke. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Bioinspired Design of a Superoleophobic and Low Adhesive Water/Solid Interface,

ADVANCED MATERIALS, Issue 6 2009
Mingjie Liu
The wetting/antiwetting behavior of liquid droplets on a solid surface is not an apparent or simple contact between two phases, but among three phases. Inspired by the antiwetting behavior of oil droplets on fish scales in water, a superoleophobic and low-adhesive interface is created on a solid substrate with micro/nanohierarchical structures, using oil/water/solid three-phase systems. [source]


Small-angle X-ray scattering investigation of water droplets in mist

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007
Yohko F. Yano
Small-angle X-ray scattering measurements of water droplets in a mist were carried out using the BL15XU beamline at SPring-8. The diameter of the water droplets generated by ultrasonic atomization was found to be , 50,nm and had no distribution in the range under 50,nm, as predicted. The study also showed how difficult it is to measure the small-angle scattering of low-density materials, such as liquid droplets in a mist. [source]


Electrosprayed polymer particles: Effect of the solvent properties

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2009
Chul Ho Park
Abstract Electrospraying technology has been studied in many fields to produce particles of various substances from nanoscale to microscale sizes. Unlike pure liquids, droplets formed by electrospraying that are comprised of polymer solutions undergo additional solidification processes involving solvent evaporation, which primarily determine the particle size and morphology. Herein, the effects of the solvent properties on the morphology and dimensions of solidified particles were systematically studied. In general, the size of the solidified spherical particles with smooth surfaces reflected that of the initially formed liquid droplets, which could partially be estimated by theoretical equations developed for pure liquids. Particle sizes increased with an increase in polymer content and a decrease in the boiling point of the volatile solvent. Inhomogeneous drying processes related to phase separation or skin formation resulted in hollow, cuplike, and porous particle structures, with particle sizes and morphologies that were outside of the scope of the theoretical treatments. The selection of a proper solvent or solvent mixture seemed to be a convenient way to control the particle morphologies, such as hollow, cuplike, or porous structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]


Liquid Rb micrometric droplets confined in paraffin wax: an X-ray absorption spectroscopy study

JOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001
Simone De Panfilis
We have performed high-quality X-ray absorption measurements on crystalline (c -Rb) and liquid (l -Rb) Rubidium in the range from 15 K to 320 K. Performing a consistent analysis that takes into account the contribution of the medium range structure, we observe that the l -Rb spectrum is compatible with pair correlation function g(r) previously determined by neutron diffraction experiments. Due to the micrometric size of the liquid droplets we were able to observe a slight undercooling down to 290 K. We were also able to study the details of the very strong multielectron excitations channels in terms of resonances, edges and shake-off features at proper theoretical energy values. [source]


Study of liquid droplets impact on dry inclined surface

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009
Jie Cui
Abstract The impact of droplets on the surface is a common phenomenon. The outcome of a droplet impacting on a solid surface depends on the properties of the liquid, the surface conditions and the kinematics parameters, i.e. velocity and momentum. During the impact process, the phenomenons, such as spread, rebound, often appear. This paper presents the results of an experimental investigation of droplets impacting on inclined solid surface at low velocity. The effects of the impact parameters on the droplet impingement are studied. Measures were performed using a high-speed camera. It has been shown that the impacting droplets spread on the surface until liquid surface tension and viscosity overcame inertial forces, after which they recoiled off the surface. The maximum diameter of a droplet spread was measured. In addition, a further forecasting expression has been obtained through energy model when a droplet impacts on an inclined surface without splashing. It is found that it is in good agreement with experimental value and can well predict the maximum spread diameter. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]


Crystallization and preliminary crystallographic studies of a new crystal form of Escherichia colil -­asparaginase II (Ser58Ala mutant)

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2000
Maciej Kozak
Periplasmic Escherichia colil -asparaginase II with an Ser58Ala mutation in the active-site cavity has been crystallized in a new orthorhombic form (space group P21212). Crystals of this polymorph suitable for X-ray diffraction have been obtained by vapour diffusion using two sets of conditions: (i) 1% agarose gel using MPD as precipitant (pH 4.8) and (ii) liquid droplets using PEG-MME 550 (pH 9.0). The crystals grown in agarose gel are characterized by unit-cell parameters a = 226.9, b = 128.4, c = 61.9,Å and diffract to 2.3,Å resolution. The asymmetric unit contains six protein molecules arranged into one pseudo-222-symmetric homotetramer and an active-site competent dimer from which another homotetramer is generated by crystallographic symmetry. [source]


Study on Evaporating Characteristics of a Coaxial Two Impinging-Stream Concentrator

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2006
J. Yan
Abstract Based on the coaxial two impinging-streams principle, a new device for solution concentration was built and studied theoretically and experimentally. The experimental study focused on the effects of inlet air temperature, inlet air flow rate, and accelerating pipe length on the volumetric evaporative coefficient of the impinging-stream concentrator (ISC). The results show that the ISC has a relatively high volumetric evaporative coefficient, which increases with higher inlet air flow rates and higher inlet air temperature, and the ISC with a shorter accelerating pipe is more efficient. A theoretical model was suggested based on the consideration of mass, heat, and momentum transfers between liquid droplets and hot air. The concentration process of a sucrose solution in the ISC was simulated using the model and the results were compared with the experimental results, which indicated that the suggested model is reliable with a maximum relative error of less than 6.6,%. [source]