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Статті в журналах з теми "Emulsion droplets":
1
Bromley, Keith M., and Cait E. MacPhee. "BslA-stabilized emulsion droplets with designed microstructure." Interface Focus 7, no. 4 (June 16, 2017): 20160124. http://dx.doi.org/10.1098/rsfs.2016.0124.
Анотація:
Emulsions are a central component of many modern formulations in food, pharmaceuticals, agrichemicals and personal care products. The droplets in these formulations are limited to being spherical as a consequence of the interfacial tension between the dispersed phase and continuous phase. The ability to control emulsion droplet morphology and stabilize non-spherical droplets would enable the modification of emulsion properties such as stability, substrate binding, delivery rate and rheology. One way of controlling droplet microstructure is to apply an elastic film around the droplet to prevent it from relaxing into a sphere. We have previously shown that BslA, an interfacial protein produced by the bacterial genus Bacillus , forms an elastic film when exposed to an oil- or air–water interface. Here, we highlight BslA's ability to stabilize anisotropic emulsion droplets. First, we show that BslA is capable of arresting dynamic emulsification processes leading to emulsions with variable morphologies depending on the conditions and emulsification technique applied. We then show that frozen emulsion droplets can be manipulated to induce partial coalescence. The structure of the partially coalesced droplets is retained after melting, but only when there is sufficient free BslA in the continuous phase. That the fidelity of replication can be tuned by adjusting the amount of free BslA in solution suggests that freezing BslA-stabilized droplets disrupts the BslA film. Finally, we use BslA's ability to preserve emulsion droplet structural integrity throughout the melting process to design emulsion droplets with a chosen shape and size.
2
Yong, Ah Pis, Md Aminul Islam, and Nurul Hasan. "The Effect of pH and High-Pressure Homogenization on Droplet Size." International Journal of Engineering Materials and Manufacture 2, no. 4 (December 10, 2017): 110–22. http://dx.doi.org/10.26776/ijemm.02.04.2017.05.
Анотація:
The aims of this study are to revisit the effect of high pressure on homogenization and the influence of pH on the emulsion droplet sizes. The high-pressure homogenization (HPH) involves two stages of processing, where the first stage involves in blending the coarse emulsion by a blender, and the second stage requires disruption of the coarse emulsion into smaller droplets by a high-pressure homogenizer. The pressure range in this review is in between 10-500 MPa. The homogenised droplet sizes can be reduced by increasing the homogenization recirculation, and there is a threshold point beyond that by applying pressure only, the size cannot be further reduced. Normally, homogenised emulsions are classified by their degree of kinetic stability. Dispersed phase present in the form of droplets while continuous phase also known as suspended droplets. With a proper homogenization recirculation and pressure, a more kinetically stable emulsion can be produced. The side effects of increasing homogenization pressure are that it can cause overprocessing of the emulsion droplets where the droplet sizes become larger rather than the expected smaller size. This can cause kinetic instability in the emulsion. The droplet size is usually measured by dynamic light scattering or by laser light scattering technique. The type of samples used in this reviews are such as chocolate and vanilla based powders; mean droplet sizes samples; basil oil; tomato; lupin protein; oil; skim milk, soymilk; coconut milk; tomato homogenate; corn; egg-yolk, rapeseed and sunflower; Poly(4-vinylpyridine)/silica; and Complex 1 until complex 4 approaches from author case study. A relationship is developed between emulsion size and pH. Results clearly show that lower pH offers smaller droplet of emulsion and the opposite occurs when the pH is increased.
3
Silva, T. M., N. N. P. Cerize, and A. M. Oliveira. "The Effect of High Shear Homogenization on Physical Stability of Emulsions." International Journal of Chemistry 8, no. 4 (September 28, 2016): 52. http://dx.doi.org/10.5539/ijc.v8n4p52.
Анотація:
<p class="03Abstract">Emulsions are thermodynamically unstable systems where droplet size is one of the main factors that affect its physical stability and consequently their quality. In this context, this work analyses the incorporation of a high shear homogenization step in the manufacturing process of an emulsion with the objective of maintaining its physical stability. In order to demonstrate the effects of this homogenization in the manufacturing process, the emulsion characterization was carried out by microscopy, rheology, laser diffraction and analytical photo-centrifugation techniques. The effect of high shear homogenization into the emulsion physical results was dependent on the speed applied to the homogenizer pump, with an effective 3600 rpm speed. There was no evidence of change on pH attributes and emulsion density, although there was a change in volumetric relationship between the droplet family presented in each sample, reducing the population of larger droplets to form a third family of intermediate droplets and increasing the volumetric proportion of the population of smaller droplets. This profile change in the droplet size distribution contributed to increased viscosity and emulsion without the presence of separation after it was submitted to the stress condition of temperature and agitation.</p>
4
Li, Chun, Jian Ouyang, Fangjie Dou, and Jingtao Shi. "Mechanism Influencing the Drying Behavior of Bitumen Emulsion." Materials 14, no. 14 (July 12, 2021): 3878. http://dx.doi.org/10.3390/ma14143878.
Анотація:
The drying process of bitumen emulsion largely dominates the strength development of emulsion-based mixtures for pavement structure, thus it can be used to judge the quality of bitumen emulsion. However, the drying behaviour of bitumen emulsions was seldom considered. The emulsion drying and film formation theory are employed to study the drying process of different bitumen emulsions with a thin layer. Results indicated the drying process of bitumen emulsion can be divided into three stages: (a) an initial high evaporation rate stage; (b) an intermediate stage with a rapidly decreasing evaporation rate; (c) a final stage with a very small evaporation rate. The boundaries among the three stages can be identified by studying the water evaporation rate. Three drying parameters, i.e., the critical volume fractions of bitumen defining the boundaries among the three stages and the maximum packing fraction of bitumen droplets, are proposed to quantitatively characterize the drying behavior of bitumen emulsion. High values of these parameters indicate a bitumen emulsion that has rapid drying behavior. Therefore, these parameters are independent of the emulsifier type, but they are highly dependent on the bitumen’s droplet size. These drying parameters increase with a decrease in bitumen droplet size. Therefore, bitumen emulsion with a smaller size distribution of bitumen droplets can have a more rapid drying behavior, which is recommended in real engineering.
5
Jiang, Tianyi, Yankai Jia, Haizhen Sun, Xiaokang Deng, Dewei Tang, and Yukun Ren. "Dielectrophoresis Response of Water-in-Oil-in-Water Double Emulsion Droplets with Singular or Dual Cores." Micromachines 11, no. 12 (December 17, 2020): 1121. http://dx.doi.org/10.3390/mi11121121.
Анотація:
Microfluidic technologies have enabled generation of exquisite multiple emulsion droplets, which have been used in many fields, including single-cell assays, micro-sized chemical reactions, and material syntheses. Electrical controlling is an important technique for droplet manipulation in microfluidic systems, but the dielectrophoretic behaviors of multiple emulsion droplets in electrical fields are rarely studied. Here, we report on the dielectrophoresis response of double emulsion droplets in AC electric fields in microfluidic channel. A core-shell model is utilized for analyzing the polarization of droplet interfaces and the overall dielectrophoresis (DEP) force. The water-in-oil-in-water droplets, generated by glass capillary devices, experience negative DEP at low field frequency. At high frequency, however, the polarity of DEP is tunable by adjusting droplet shell thickness or core conductivity. Then, the behavior of droplets with two inner cores is investigated, where the droplets undergo rotation before being repelled or attracted by the strong field area. This work should benefit a wide range of applications that require manipulation of double emulsion droplets by electric fields.
6
Spicer, Patrick T., and Richard W. Hartel. "Crystal Comets: Dewetting During Emulsion Droplet Crystallization." Australian Journal of Chemistry 58, no. 9 (2005): 655. http://dx.doi.org/10.1071/ch05119.
Анотація:
Liquid oil emulsion droplets can violently dewet their own solid crystals during crystallization as a result of surfactant adsorption. The crystal shape formed is a function of the relative rates of dewetting and crystallization as controlled by surfactant adsorption, cooling rate, and lipid purity. For negligible dewetting rates, crystals nucleate and grow within the droplet. At similar crystallization and dewetting rates, the droplet is propelled around the continuous phase on a crystalline ‘comet tail’ much larger than the original droplet. Rapid dewetting causes the ejection of small discrete crystals across the droplet’s oil–water interface.
7
Zheng, Hongxia, Like Mao, Jingyi Yang, Chenyu Zhang, Song Miao, and Yanxiang Gao. "Effect of Oil Content and Emulsifier Type on the Properties and Antioxidant Activity of Sea Buckthorn Oil-in-Water Emulsions." Journal of Food Quality 2020 (January 13, 2020): 1–8. http://dx.doi.org/10.1155/2020/1540925.
Анотація:
Sea buckthorn oil-in-water emulsions were prepared through high pressure homogenization, and the effects of droplet size, oil content, and emulsifier type on emulsion properties and the overall antioxidant activity of the emulsions were evaluated. Emulsions with different droplet size were obtained by varying homogenization pressure, and higher oil content resulted in bigger droplet size of the emulsions. Among three tested emulsifiers, sodium caseinate and sugar ester were able to form emulsions with much smaller particle size than soy protein isolate. The emulsions with bigger droplets tended to cream in an accelerated centrifugation test. The antioxidant property of the emulsions was expressed as their DPPH radical scavenging activity. The emulsions processed at lower pressure or contained higher oil content had higher DPPH radical scavenging activity. The soy protein isolate-stabilized emulsion presented higher antioxidant activity than sodium caseinate- and sugar ester-stabilized ones. Upon storage, the antioxidant activity of the emulsions was decreased due to the changes in emulsion stability and the degradation of antioxidants. The knowledge obtained in this study would be useful in developing healthy food containing sea buckthorn oil.
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Fingas, Merv. "OIL SPILL DISPERSION STABILITY AND OIL RE-SURFACING." International Oil Spill Conference Proceedings 2008, no. 1 (May 1, 2008): 661–65. http://dx.doi.org/10.7901/2169-3358-2008-1-661.
Анотація:
ABSTRACT This paper summarizes the data and the theory of oil-in-water emulsion stability resulting in oil spill dispersion re-surfacing. There is an extensive body of literature on surfactants and interfacial chemistry, including experimental data on emulsion stability. The phenomenon of resurfacing oil is the result of two separate processes: de stabilization of an oil-in-water emulsion and desorption of surfactant from the oil-water interface which leads to further de stabilization. The de stabilization of oil-in-water emulsions such as chemical oil dispersions is a consequence of the fact that no emulsions are thermodynamically stable. Ultimately, natural forces move the emulsions to a stable state, which consists of separated oil and water. What is important is the rate at which this occurs. An emulsion is said to be kinetically stable when significant separation (usually considered to be half or 50% of the dispersed phase) occurs outside of the usable time. There are several forces and processes that result in the destabilization and resurfacing of oil-in-water emulsions such as chemically dispersed oils. These include gravitational forces, surfactant interchange with water and subsequent loss of surfactant to the water column, creaming, coalescence, flocculation, Ostwald ripening, and sedimentation. Gravitational separation is the most important force in the resurfacing of oil droplets from crude oil-in-water emulsions such as dispersions. Droplets in an emulsion tend to move upwards when their density is lower than that of water. Creaming is the de stabilization process that is simply described by the appearance of the starting dispersed phase at the surface. Coalescence is another important de stabilization process. Two droplets that interact as a result of close proximity or collision can form a new larger droplet. The result is to increase the droplet size and the rise rate, resulting in accelerated de stabilization of the emulsion. Studies show that coalescence increases with increasing turbidity as collisions between particles become more frequent. Another important phenomenon when considering the stability of dispersed oil, is the absorption/desorption of surfactant from the oil/water interface. In dilute solutions, much of the surfactant in the dispersed droplets ultimately partitions to the water column and thus is lost to the dispersion process. This paper provides a summary of the processes and data from some experiments relevant to oil spill dispersions.
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Xu, Ke, Peixi Zhu, Tatiana Colon, Chun Huh, and Matthew Balhoff. "A Microfluidic Investigation of the Synergistic Effect of Nanoparticles and Surfactants in Macro-Emulsion-Based Enhanced Oil Recovery." SPE Journal 22, no. 02 (September 23, 2016): 459–69. http://dx.doi.org/10.2118/179691-pa.
Анотація:
Summary Injecting oil-in-water (O/W) emulsions stabilized with nanoparticles (NPs) or surfactants is a promising option for enhanced oil recovery (EOR) in harsh-condition reservoirs. Stability and rheology of the flowing emulsion in porous media are key factors for the effectiveness of the EOR method. The objective of this study is to use microfluidics to (1) quantitatively evaluate the synergistic effect of surfactants and NPs on emulsion dynamic stability and how NPs affect the emulsion properties, and to (2) investigate how emulsion properties affect the sweep performance in emulsion flooding. A microfluidic device with well-defined channel geometry of a high-permeability pathway and multiple parallel low-permeability pathways was created to represent a fracture/matrix dual-permeability system. Measurement of droplet coalescence frequency during flow is used to quantify the dynamic stability of emulsions. An NP aqueous suspension (2 wt%) shows excellent ability to stabilize the macro-emulsion when mixed with a trace amount of surfactant (0.05 wt%), revealing a synergistic effect between NPs and surfactant. For a stable emulsion, when a pore throat is present in the high-permeability pathway, it was observed that flowing emulsion droplets compress each other and then block the high-permeability pathway at a throat structure, which forces the wetting phase into low-permeability pathways. Droplet size shows little correlation with this blocking effect. Water content was observed to be much higher in the low-permeability pathways than in the high-permeability pathways, indicating different emulsion texture and viscosity in channels of different sizes. Consequently, the assumption of bulk emulsion viscosity in the porous medium is not applicable in the description and modeling of the emulsion-flooding process. Flow of emulsions stabilized by an NP/surfactant mixture shows droplet packing in high-permeability regions that is denser than those stabilized by surfactant only, at high-permeability regions, which is attributed to the enhanced interaction between droplets caused by NPs in the thin liquid film between neighboring oil/water (O/W) interfaces. This effect is shown to enhance the performance of emulsion-blockage effect for sweep-efficiency improvement, showing the advantage of NPs as an emulsion stabilizer during an emulsion-based EOR process.
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Jarzębski, Maciej, Przemysław Siejak, Wojciech Smułek, Farahnaz Fathordoobady, Yigong Guo, Jarosław Pawlicz, Tomasz Trzeciak, et al. "Plant Extracts Containing Saponins Affects the Stability and Biological Activity of Hempseed Oil Emulsion System." Molecules 25, no. 11 (June 10, 2020): 2696. http://dx.doi.org/10.3390/molecules25112696.
Анотація:
In this study, two saponins-rich plant extracts, viz. Saponaria officinalis and Quillaja saponaria, were used as surfactants in an oil-in-water (O/W) emulsion based on hempseed oil (HSO). This study focused on a low oil phase content of 2% v/v HSO to investigate stable emulsion systems under minimum oil phase conditions. Emulsion stability was characterized by the emulsification index (EI), centrifugation tests, droplet size distribution as well as microscopic imaging. The smallest droplets recorded by dynamic light scattering (droplets size v. number), one day after the preparation of the emulsion, were around 50–120 nm depending the on use of Saponaria and Quillaja as a surfactant and corresponding to critical micelle concentration (CMC) in the range 0–2 g/L. The surface and interfacial tension of the emulsion components were studied as well. The effect of emulsions on environmental bacteria strains was also investigated. It was observed that emulsions with Saponaria officinalis extract exhibited slight toxic activity (the cell metabolic activity reduced to 80%), in contrast to Quillaja emulsion, which induced Pseudomonas fluorescens ATCC 17400 growth. The highest-stability samples were those with doubled CMC concentration. The presented results demonstrate a possible use of oil emulsions based on plant extract rich in saponins for the food industry, biomedical and cosmetics applications, and nanoemulsion preparations.
Дисертації з теми "Emulsion droplets":
1
Wilking, Connie Chang. "Viral encapsulation of emulsion and nanoemulsion droplets." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1692370451&sid=4&Fmt=2&clientId=1564&RQT=309&VName=PQD.
2
Sachdev, Suchanuch. "Emulsion droplets as reactors for assembling nanoparticles." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/36206.
Анотація:
Materials on the nanoscale have very interesting properties. Hence, they are commonly used for a variety of applications such as drug delivery, bio-imaging and sensing devices. Moreover, coating these particles with other materials forming core@shell or Janus particles can further enhance their properties. However, for the particles to be used in medical and electronic devices, their properties such as size, shape and composition need to be precisely controlled. In this PhD., an emulsification technique was chosen to investigate the synthesis of nanoparticles; it is a simple process, does not require any harsh chemicals or temperature and is fast. Emulsification occurs when two or more immiscible liquids and surfactants are mixed. Here, emulsion droplets were produced using a microfluidic device which allowed for the creation of uniform droplets. These were employed as templates to synthesise and assemble nanomaterials. The main aim of the Ph.D. was to develop a droplet based synthesis process to generate nanoparticles and then assemble them into core@shell particles. This Ph.D., starts by synthesising Fe3O4 nanoparticles (~ 12 nm) and assembling them into microparticles (~ 1µm 2µm) using emulsion droplets as microreactors. By tuning the surfactant, droplet size and evaporation rate of the dispersed phase, microparticles of varying shapes and sizes, such as spherical or crumbled shapes, were produced. When these particles are compared with the commercially available particles, the magnetic content of the in-house particles, or sometimes referred to as Loughborough University Enterprises Ltd. (LUEL), are much higher and more uniform, hence resulting in faster separation when used for extraction of analytes. LUEL particles were supplied as part of commercial collaboration. The use of Pickering emulsions were then explored to create core@shell particles using gold nanoparticles instead of a surfactant to produce gold shells and the addition of pre-synthesised Fe3O4 nanoparticles results in Fe3O4@Au core@shell particles. This is the first time Pickering emulsions were used to produce Fe3O4@Au core@shell particles (~ 1.5 µm) within a microfluidic device. However, the shells were not uniform in thickness. In order to improve the coverage, nanoparticles were synthesised in situ at the droplet interface. By placing the gold chloride (AuCl4-) in the continuous phase and by varying the concentration of the electron donor in hexane droplet, single crystal gold nanoparticles and platelets were formed. The reaction is spontaneous at room temperature, creating gold nanoparticles at the interface of the emulsion droplet. The size and shape of the gold nanoparticles were controlled by varying the concentration of the reactants and the size of the droplets. By adding pre-synthesised particles (Fe3O4 nanoparticles) to the droplet, Au@Fe3O4 core@shell particles were formed with an approximate size of 250 nm. The same concept of forming core@shell particles using gold nanoparticles was further expanded by using other metal ions; palladium and silver. Unlike gold, palladium and silver only formed spherical nanoparticles, no platelets were observed. The addition of preformed iron oxide nanoparticles to the palladium results in core@shell particles. However, in the case of silver, no core@shell particles were formed. The study of the rate of reaction was conducted to understand the details of the mechanism. Overall, the process developed in this Ph.D. study allows for the facile synthesis of core@shell particles in a rapid, high throughput reaction. In the future, it is believed it could be scaled up for commercial purposes.
3
Patel, Vishal M. "Synthesis of calcium carbonate coated emulsion droplets for drug detoxification." [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1001175.
4
Pangu, Gautam D. "ACOUSTICALLY AIDED COALESCENCE OF DROPLETS IN AQUEOUS EMULSIONS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1138379076.
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Nagelberg, Sara(Sara Nicole). "Dynamic and stimuli-responsive multi-phase emulsion droplets for optical components." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127708.
Анотація:
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020
Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 136-143).
Dynamic micro-optical components have revolutionized imaging, sensing, and display technologies. Multi-phase emulsions are micro-scale droplets formed from multiple immiscible material components suspended in a fluid medium. An interesting aspect of these droplets is that by tailoring the chemistry of the surrounding medium it is possible to control the droplet morphology or to render the droplets responsive to stimuli in the environment, including light, heat, specific molecules, or even bacteria. This thesis explores the optical characteristics of multi-phase droplets, including their refractive, emissive, and reflective properties. This work focuses predominantly on bi-phase droplets formed from two immiscible oils in water, which form double emulsions or Janus droplets. As tunable refractive components, these droplets form dynamic compound micro-lenses with adjustable focal length that is continuously variable from converging lenses to diverging lenses.
Macroscopically these refractive droplets can appear nearly transparent or strongly scattering, depending on their configurations. When a fluorescent dye is dispersed within the higher refractive index phase, a portion of the light emitted will undergo total internal reflection. This results in a strong morphology-dependent angular emission profile, which can be used in molecular sensing for chemicals or pathogens. In reflection, the droplets produce striking iridescent colors. This is due to the interference light being totally internally reflected at the internal interface along distinct optical paths, leading to color. These optical characteristics are analyzed both experimentally and theoretically. Finite Difference Time Domain simulations were used to model wave-optical effects and phenomena that could be treated using geometrical optics were calculated using a custom-built ray tracing algorithm.
Additionally, a theoretical model was developed to explain the iridescent colors, under a geometric approximation that takes into account interference effects. Experimentally the droplets were characterized using several different custom-built microscope setups. Beyond the optical characteristics, we used these setups to investigate the effects of thermal Marangoni flows within the droplets, which cause the droplets to re-orient towards a heat source. This work sets the foundation of understanding the refractive, reflective, and emissive properties of multi-phase droplets, which could form the basis of dynamically controllable or stimuli-responsive micro-scale optical components.
by Sara Nagelberg.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering
6
Wang, Yiwei. "Coalescence and disproportionation of air bubbles stabilized by proteins and emulsion droplets." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496337.
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Lange, Tobias. "Precipitation in confined droplets - development of microfluidic and imogolite Pickering emulsion approaches." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLV069.
Анотація:
Dans de nombreux secteurs industriels tels que la production de pigments, de catalyseurs, de produits pharmaceutiques, de minerais ou le recyclage de combustibles nucléaire, les étapes de précipitation et de cristallisation sont cruciales. Bien que ces procédés soient utilisés à grandes échelles avec un contrôle relatif des solides formés, les mécanismes de formation ne sont pas toujours bien compris, en particulier à l’échelle microscopique. Une meilleure compréhension des différentes étapes de formation permettrait d’obtenir des leviers de contrôle adapté à chaque composé et application.Cette thèse se place dans ce cadre très général du contrôle de la précipitation et plus particulièrement de la précipitation en gouttes d’emulsion eau dans l’huile. Deux approches différentes ont été explorées pour moduler et suivre la réactivité dans une goutte d’emulsion. La première approche était basée sur le couplage d’une puce microfluidique générateur de gouttes avec la diffusion de rayons X aux petits angles (SAXS) in situ. Après une caractérisation complète de la compatibilité du polymère non stoechiometrique thiol-ene-epoxy (OSTE+) avec le SAXS, une puce en OSTE+ compatible avec le suivi in situ SAXS a été développée. Un traitement original permettant d’extraire séparément le signal des gouttes du signal de l’huile a permis de valider le montage dans le cas de la précipitation d’oxalate de cerium. La deuxième approche avait pour but l’utilisation de nanotubes d’imogolites pour stabiliser des gouttes d’émulsion et étudier le transport de réactifs entre gouttes via ces nanotubes. Cette approche nécessitait de fonctionnaliser les nanotubes pour les rendre hydrophobe. La caractérisation poussée de la fonctionnalisation des imogolites par des alkylphosphoniques a montré pour la première fois que cette réaction ne conduisait pas à une fonctionnalisation de surface mais à un matériau composite aux propriétés interfaciales remarquables. De nouvelles voies de fonctionnalisation de surface ont été développées pour rendre les imogolites hydrophobesIn the industrial production of pigments, catalysts, plant protection agents, nuclear fuel and pharmaceuticals precipitation and crystallization plays a fundamental role. Although these processes are often applied and a relative control over the formed solids can be achieved, the processes are not always well understood on a microscopic level. To identify how the solids are formed and which mechanisms govern their formation potentially gives the capabilities to better control such processes.In this thesis two different approaches are explored to study precipitation and crystallization by confining reactions into droplets. The first approach focuses on the combination of a droplet microfluidic device and in-situ small angle X-ray scattering. Off-stochiomestry thiol-ene-epoxy polymer is characterized for the use with in-situ X-ray scattering and a protocol is presented to prepare suitable microfluidic devices from this material. An original approach to isolate the scattering signal of the carrier phase and the droplets is then used to study the precipitation of cerium oxalate in droplets. The second approach aims to use imogolite nanotubes to stabilize droplets against coalescence and to study their transport properties to control reactant feeding into droplets. By fully characterizing the necessary surface modification by alkylphosphonic acids for the first time, evidence is found that the reaction does not yield surface modified tubes. Consequentially, new approaches are explored to obtain individually dispersed imogolite nanotubes with a hydrophobic surface
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Lattin, James R. "Ultrasound-Induced Phase Change of Emulsion Droplets for Targeted Gene and Drug Delivery." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3377.
Анотація:
This dissertation explores the potential of using perfluorocarbon emulsion droplets to add an ultrasound-sensitive element to drug delivery systems. These emulsion droplets may be induced to vaporize with ultrasound; during the rarefactional phase of an ultrasound wave, the pressure around the droplets may fall below the vapor pressure of the liquid forming the emulsion, providing a thermodynamic potential for vaporization. This ultrasound-induced phase change of the emulsion droplet could release therapeutics attached to the droplet surface or aid in drug delivery due to mechanical effects associated with vaporization and expansion, similar to the ability of cavitating bubbles to aid in drug delivery. In contrast to bubbles, stable emulsions can be formed at nano-scale sizes, allowing them to extravasate into tissues and potentially be endocytosed into cells. Perfluorohexane and perfluoropentane were selected to form the emulsions due to their relatively high vapor pressure, low water solubility, and biocompatibility. Acoustic droplet vaporization was explored for its potential to increase ultrasound-induced drug release from liposomes. Liposomes have proven to be versatile and effective drug carriers, but are not inherently responsive to ultrasound. eLiposomes, defined as a liposome with encapsulated emulsion droplets, were developed due to the potential of the expanding vapor phase to disrupt bilayer membranes. The resulting vesicle retains the advantages of liposomes for drug delivery, while adding an ultrasound-sensitive element. eLiposomes were loaded with calcein, a fluorescent molecule, as a model drug in order to quantify ultrasound-mediated drug release compared to release from conventional liposomes. Upon exposure to ultrasound, eLiposomes typically released 3 to 5 times as much of the encapsulated load compared to conventional liposomes, with some eLiposome samples approaching 100% release. Emulsion droplets were also added to the outside of conventional liposomes, but resulted in little to no increase compared to control samples without emulsions. Lastly, in vitro experiments were performed with HeLa cells to explore the ability of emulsion droplets and eLiposomes to deliver calcein inside of cells. Calcein delivery to the cytosol was accomplished, and the emulsion-containing samples demonstrated the ability to aid in endosomal escape.
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Hart, Helen Mary. "A study of the interaction between oil-in-water emulsion droplets and polymer particles." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296451.
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Lacava, Johann Verfasser], and Eduard [Akademischer Betreuer] [Arzt. "Assembly of gold nanoparticles into regular clusters inside emulsion droplets / Johann Lacava. Betreuer: Eduard Arzt." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2015. http://d-nb.info/1064868533/34.
Книги з теми "Emulsion droplets":
1
Nagelberg, Sara. Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53460-8.
2
Aveyard, Bob. Surfactants. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198828600.001.0001.
Анотація:
Characteristically, surfactants in aqueous solution adsorb at interfaces and form aggregates (micelles of various shapes and sizes, microemulsion droplets, and lyotropic liquid crystalline phases). This book is about the behaviour of surfactants in solution, at interfaces, and in colloidal dispersions. Adsorption at liquid/fluid and solid/liquid interfaces, and ways of characterizing the adsorbed surfactant films, are explained. Surfactant aggregation in systems containing only an aqueous phase and in systems with comparable volumes of water and nonpolar oil are each considered. In the latter case, the surfactant distribution between oil and water and the behaviour of the resulting Winsor systems are central to surfactant science and to an understanding of the formation of emulsions and microemulsions. Surfactant layers on particle or droplet surfaces can confer stability on dispersions including emulsions, foams, and particulate dispersions. The stability is dependent on the surface forces between droplet or particle surfaces and the way in which they change with particle separation. Surface forces are also implicated in wetting processes and thin liquid film formation and stability. The rheology of adsorbed films on liquids and of bulk colloidal dispersions is covered in two chapters. Like surfactant molecules, small solid particles can adsorb at liquid/fluid interfaces and the final two chapters focus on particle adsorption, the behaviour of adsorbed particle films and the stabilization of Pickering emulsions.
3
Cates, M. Complex fluids: the physics of emulsions. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198789352.003.0010.
Анотація:
These lectures start with the mean field theory for a symmetric binary fluid mixture, addressing interfacial tension, the stress tensor, and the equations of motion (Model H). We then consider the phase separation kinetics of such a mixture: coalescence, Ostwald ripening, its prevention by trapped species, coarsening of bicontinuous states, and the role of shear flow. The third topic addressed is the stabilization of emulsions by using surfactants to reduce or even eliminate the interfacial tension between phases; the physics of bending energy, which becomes relevant in the latter case, is then presented briefly. The final topic is the creation of long-lived metastable emulsions by adsorption of colloidal particles or nanoparticles at the fluid–fluid interface; alongside spherical droplets, these methods can be used to create a range of unconventional structures with potentially interesting properties that are only now being explored.
Частини книг з теми "Emulsion droplets":
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Nagelberg, Sara. "Thermal Actuation of Bi-Phase Droplets." In Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components, 71–82. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53460-8_5.
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Nagelberg, Sara. "Emissive Bi-Phase Droplets as Pathogen Sensors." In Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components, 33–43. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53460-8_3.
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Nagelberg, Sara. "Multi-Phase Droplets as Dynamic Compound Micro-Lenses." In Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components, 13–31. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53460-8_2.
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Patel, Vishal M., Piyush Sheth, Allison Kurz, Michael Ossenbeck, Dinesh O. Shah, and Laurie B. Gower. "Synthesis of Calcium Carbonate-Coated Emulsion Droplets for Drug Detoxification." In ACS Symposium Series, 15–25. Washington, DC: American Chemical Society, 2004. http://dx.doi.org/10.1021/bk-2004-0878.ch002.
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Matsumura, Y., H. Sakamoto, M. Motoki, and T. Mori. "Filler Effects of Oil Droplets on Physical Properties of Emulsion Gels." In Food Hydrocolloids, 409–14. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2486-1_63.
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Nagelberg, Sara. "Introduction." In Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components, 1–11. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53460-8_1.
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Nagelberg, Sara. "Structural Color from Interference of Light Undergoing Total Internal Reflection at Concave Interfaces." In Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components, 45–69. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53460-8_4.
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Nagelberg, Sara. "Summary and Outlook." In Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components, 83–84. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53460-8_6.
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Piacentini, Emma, Alessandra Imbrogno, and Lidietta Giorno. "Nanostructured Sensing Emulsion Droplets and Particles: Properties and Formulation by Membrane Emulsification." In Smart Membranes and Sensors, 367–400. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781119028642.ch13.
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Vendel, Kim J. A., Celine Alkemade, Nemo Andrea, Gijsje H. Koenderink, and Marileen Dogterom. "In Vitro Reconstitution of Dynamic Co-organization of Microtubules and Actin Filaments in Emulsion Droplets." In Methods in Molecular Biology, 53–75. New York, NY: Springer US, 2019. http://dx.doi.org/10.1007/978-1-0716-0219-5_5.
Тези доповідей конференцій з теми "Emulsion droplets":
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Yang, Haixia, Steven R. Schmid, Ronald A. Reich, and Thomas J. Kasum. "Direct Observations of Emulsion Flow in EHL Contacts." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63074.
Анотація:
Oil-in-water emulsions are widely used as lubricants in metal forming, machining and some machinery elements where non-flammable lubricants are required. Their lubricating mechanisms have been extensively investigated based on the measurements of film thickness and/or traction in the past few decades and a number of physical explanations for their performance have been forwarded. However, direct observation of the emulsion flow, as a direct method of evaluating suggested theoretical explanations, has been greatly restricted by the available instruments. In this paper, a newly devised digital video camera and microscope were used to directly observe the emulsion flow in EHL contacts at industrially relevant speeds for both line and point contacts. Previous low-speed results for line contact were confirmed and extended into high-speed cases. That is, some droplets were rejected from the inlet, others penetrated to the contact zone, and others remained fixed in position a certain distance from the edge of contact. For point contact, side flow behavior was also observed, and the number of droplets that remained stationary were limited to a single streamline. To clarify the oil droplet behavior and investigate the effect of particle size on entrainment, three tight emulsions with different mean droplet sizes were examined on an EHD rig at speeds from 12 mm/s up to 1.5 m/s.
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Chen, Jerry M., and Ming-Che Kuo. "Generation and Control of Droplet in Cross Microchannel Flow With a Converging-Diverging Nozzle Shaped Section." In ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2010. http://dx.doi.org/10.1115/esda2010-24102.
Анотація:
This paper reports flow visualization experiments of droplet emulsions in the microfluidics that is composed of a flow-focusing (cross-junction) structure with a converging-diverging nozzle shaped section. The channel structure was made of polydimethylsiloxane (PDMS) with a channel of 73 μm in depth and 100 μm in width. Oil as the continuous phase and water as the dispersed phase were injected into the cross-junction inlets to form water-in-oil droplets. It is found that adding the converging-diverging section to the cross-junction significantly reduces the droplet size without largely increases the overall flow resistance and still achieve excellent uniformity (with coefficient of variation less than 3.5%). Throat of the converging-diverging section determines the breakup location of droplet emulsion. The size of droplets is controllable in a wide range (6–116μm) through the variation of throat width between 23 and 100 μm in conjunction with the flow rates of continuous and dispersed phases. This emulsion technique demonstrates that droplets with diameter as small as 10 μm or less can be produced in microchannels having dimensions on the order of 100 μm without use of surfactants.
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Nguyen, Nam-Trung, Say-Hwa Tan, and Jing Liu. "Magnetically Mediated Formation of Ferrofluid Emulsion." In ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2011. http://dx.doi.org/10.1115/icnmm2011-58212.
Анотація:
This paper reports both experimental and numerical investigations of the formation process of ferrofluid emulsion with and without an applied magnetic field. The droplets are formed in a flow-focusing and T-junction configuration. In the experiment, a homogenous magnetic field was generated using an electromagnet. The presence of the magnetic field in the flow direction affects the formation process and changes the size of the droplets. In both configurations, the change in the droplet size depends on the magnetic field strength and the flow rates. A numerical model was used to investigate the force balance during the droplet breakup process. The particle level set method was employed to capture the interface movement between the continuous fluid and the dispersed fluid. The process of the droplet formation and the flow field is discussed for both cases with and without the magnetic field. Finally, experimental and numerical results are compared. The results show that the polarity of the magnetic field does not affect the formation process.
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Kovaleva, Liana, Ayrat Musin, Rasul Zinnatullin, and Iskander S. Akhatov. "Destruction of Water-in-Oil Emulsions in Electromagnetic Fields." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62935.
Анотація:
The problem of water-in-oil emulsion destruction is related to many technological processes in the oil-and-gas industry, especially in extracting and processing of oil, preparation and transportation of oil, and liquidation/recycling of oil-sludge barns. High stability of water-in-oil emulsions is principally conditioned by the presence in oils of heavy high-molecular polar components that envelope water droplets and prevent coalescence of these droplets. Using conventional techniques to destroy the emulsions yields no positive results. Employing electromagnetic field energy is one of the ways to address this problem. The paper presents the results of an experimental study of the water-in-oil emulsion destruction in radio-frequency and microwave electromagnetic fields. A mathematical model is also proposed to describe the process of electromagnetic impact on water-in-oil emulsions.
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Li, Xiaoyi, and Kausik Sarkar. "Rheological Aspects of Drops Deforming in Finite Reynolds Number Oscillatory Extensional Flows." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56648.
Анотація:
The evolving morphology of droplets in a flowing emulsion determines its rheological properties. A two-way interaction between drops and the flow governs the rheological stresses arising from drop deformation. In this paper, the rheology of droplet emulsions under oscillatory extensional flow is investigated using direct numerical simulation (DNS). The deformation of a three dimensional drop is simulated. The rheological responses are related with the interface morphology using Bachelor’s stress formulation [6]. Detailed investigation of the variation of parameters such as interfacial tension, flow frequency and inertia displayed complex non-Newtonian response of the emulsion that will have broad implication in industrial applications. The results are explained and discussed with a simple model for the drop dynamics.
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Neves, Marcos A., Isao Kobayashi, and Mitsutoshi Nakajima. "Scaling-Up Microchannel Emulsification Foreseeing Novel Bioactives Delivery Systems." In ASME 2013 11th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icnmm2013-73116.
Анотація:
In the recent years, emulsification technologies that generate droplets individually have attracted a great deal attention in various fields, e.g., for chemicals, cosmetics, foods, and pharmaceuticals. Such drop-by-drop emulsification technologies include membrane emulsification using microporous membranes and microchannel (MC) emulsification, among others. The authors developed MC emulsification chips, consisting of parallel microgrooves or compactly arranged straight through-holes. Using this MC emulsification technique, the authors have evaluated the formulation a two-phase system consisting of size-controlled O/W emulsions loaded with bioactive molecules, such as β-carotene or γ-oryzanol, PUFAs or polyphenols. The MC emulsification process enabled the production of β-carotene-loaded O/W emulsions with average droplet size (dav) of 27.6 μm and coefficient of variation (CV) of 2.3% and γ-oryzanol-loaded droplets with dav of 28.8 μm and CV of 3.8%. The highly monodisperse O/W emulsions were physically stable during up 4 months storage in darkness at 5 °C. In addition, we investigated the formation characteristics of O/W emulsion droplets in the presence of electrolyte by MC emulsification using differently charged surfactants. Droplet formation was conducted by pressurizing a dispersed phase (refined soybean oil) through the MC silicon chip into a continuous phase containing 1.0 wt% of sodium dodecyl sulfate (SDS) or polyoxyethylene (20) sorbitan monolaurate (Tween 20), and an electrolyte (NaCl) (0–1.0 mol/L). Monodisperse O/W emulsions with an dav of 26 μm and a CV below 5% were produced when the NaCl concentration was lower than a threshold level that is 0.3 mol/L for SDS and 0.5 mol/L for Tween 20. The authors also developed a large MC emulsification device including a newly designed asymmetric MC array chip to realize the mass production of uniformly sized droplets on a liter per hour scale, so that satisfying the minimum droplet productivity needed for industrial-scale production. The large MC emulsification device has a potential droplet productivity exceeding several tons per year, which could satisfy a minimum industrial-scale production of monodisperse microdispersions containing emulsion droplets, microparticles, and microcapsules loaded with bioactive compounds. Such systems have as continuously increasing potential application in the formulation of functional foods, providing a good opportunity to improve the solubility of bioactive compounds, so that increasing their bioavailability.
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Ma, Liran, Jianbin Luo, and Chenhui Zhang. "Behavior of O/W Emulsion Under Point Contact." In ASME/STLE 2012 International Joint Tribology Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ijtc2012-61091.
Анотація:
Worldwide efforts to illuminate the behavior of multiple-phase liquid are frequently focused on oil-in-water emulsions. With the aim to reveal the machanism of the film formation of aqueouse emulsion in confinement, we observed the behavior of O/W confined in a nanogap. We have observed the oil pool formed surrounding the contact area in the inlet, derived from the oil film adhered on the solid surfaces, as well as the research into how the oil pool changes with rolling speed and feeding mode. Two regions have been found in the outlet area, which are defined as vaccum region and turn-round region. Small droplets have been observed to turn round in the turn-round region, with a diminishing droplet-size distribution. Moreover, by employing two different feeding modes, we have demonstrated a suprising discovery diametrically opposed to the traditional concept. The film formation has been detedcted to be distinctly enhanced under an insufficient feeding condition compared to the situation under a sufficient feeding condition. The unusual performance leads to an strong evidence of the reemulsification concept. Here, we demonstrate, directly from experimentally observations of emulsion behaivors, that the film formation of emulsion is significantly affected by the droplet behavior.
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Akhmetov, Alfir T., Marat V. Mavletov, Sergey P. Sametov, Artur A. Rakhimov, Azat A. Valiev, and Iskander S. Akhatov. "Dispersion Flow in Microchannels." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86618.
Анотація:
The work is devoted to experimental investigations of the features of flow of dispersions in microchannels. The paper consists of three parts. In the first part the flow of emulsions in smooth contracting cylindrical microchannels is investigated. It is received that a significant role at dynamic blocking of channels is played by the inclusions comparable by size to the diameter of a narrowing. This is in spite of the fact that their influence on the change of a flow rate of emulsion before blocking is insignificant. In the second part the generation of emulsion in a complex structure of microchannels (micromodels) when water is displaced by composition of hydrocarbon with surfactants is investigated. The experimental dependences of the rheological characteristics of emulsions based on the composition of SAS and water at different concentrations of the aqueous phase can explain blocking of a porous structure by generated emulsion. In the third part a comparison of flow of water-in-oil emulsions with the suspension which was obtained by freezing the microdroplets of the aqueous phase of emulsions was studied. It was found that the blocking of suspension is not as complete as in the case of emulsion. It is explained by deformation of the droplets and by formation of a dense structure, as opposed to suspension of beads, through which hydrocarbon phase is filtered. A small increase in effective viscosity due to solidification of freezing droplets of the dispersed phase was found.
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Guo, Kai, Yuling Lv, Limin He, Xiaoming Luo, and Donghai Yang. "Investigation on Corrosion Base Characteristics and Deep Dehydration Technology of Micro-Droplets in Oil Pipelines." In ASME 2019 Asia Pacific Pipeline Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/appc2019-7617.
Анотація:
Abstract Corrosion is an important cause of steel pipeline failure and oil leakage, especially local pitting corrosion in long distance crude oil pipelines. Deep dehydration is of great significance to pipeline anticorrosion, however, further experimental results show that it is very difficult to achieve deep dehydration by a single electric field. Recent studies have shown that the particle size change of dispersed phase for the emulsion with large droplets after electromagnetic synergistic treatment is more obvious than that of a single electric field. In this study, the effect of micro-droplets on corrosion of oil pipelines are revealed. The role of micro-droplets in the process of microbial corrosion and electrochemical corrosion in a strong or weak acid solution for oil pipelines was summarized. A structural model of on-line tubular electromagnetic synergistic intensification coalescing device was established. The size change of particle of the dispersed phase in emulsions was studied. Crude oil and water were used as experimental materials, and the particle size distribution of dispersed phase in emulsions was tested by the evaluation system. The results showed that mean radius, d10 and d50 of water droplets in emulsion treated by electromagnetic synergism are larger than those treated by a single electric field. Strengthening droplets coalescence by electromagnetic synergism is also effective on emulsions whose particle size of the dispersed phase is less than 100μm. The role of micro-droplets in pitting corrosion is summarized based on corrosion channels. In the process of microbial corrosion and electrochemical corrosion in strong or weak acid solution, the role of water is presented in two aspects like participating in the reaction and providing ion electron transmission media. Analogous to culture medium, micro water droplets can be called corrosion medium for pitting corrosion in long-distance crude oil pipelines. A structural model of on-line tubular electromagnetic synergistic intensification coalescing device was established, including an electric field generation device and a magnetic field excitation component with orthogonal distribution and synchronous synergy. And emulsions are treated by electric and magnetic fields while flowing through the medium channel. The particle size change of dispersed phase in emulsions with average particle size of dispersed phase less than 100μm was experimental studied. It is found that mean radius, d10 and d50 of water droplets in emulsion treated by electromagnetic synergism are larger than that by a single electric field. Therefore, electromagnetic synergism can further enhance the dehydration depth compared with a single electric field.
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Cho, Young-Sang, Gi-Ra Yi, Seung-Man Yang, Young-Kuk Kim, and Chul-Jin Choi. "Self-assembly of bimodal particles inside emulsion droplets." In SPIE NanoScience + Engineering, edited by Oleg V. Prezhdo. SPIE, 2010. http://dx.doi.org/10.1117/12.861029.
Звіти організацій з теми "Emulsion droplets":
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Dagata, John A., Natalia Farkas та John A. Kramer. Method for Measuring the Volume of Nominally 100 μm Diameter Spherical Water-in-Oil Emulsion Droplets. National Institute of Standards and Technology, лютий 2016. http://dx.doi.org/10.6028/nist.sp.260-184.