Academic literature on the topic 'Compound droplets'
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Journal articles on the topic "Compound droplets"
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Xing, Lei, Jinyu Li, Minghu Jiang, and Lixin Zhao. "Dynamic behavior of compound droplets with millimeter-sized particles impacting substrates with different wettabilities." Physics of Fluids 35, no. 2 (February 2023): 022108. http://dx.doi.org/10.1063/5.0137505.
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The dynamic behavior of compound droplets, which are made up of a millimeter-sized particle and distilled water, impacting substrates of different wettabilities is investigated via high-speed photography. The effects of the size of the particle within the compound droplet, substrate contact angle, and impact height on the deformation of the droplets and the characteristics of the impact are analyzed. It is found that the collisions of compound droplets with substrates can be classified into four categories based on the observed experimental phenomena that occur during the impact. These categories are referred to as adhesion collision, rebound collision, daughter-droplet collision (or partial rebound collision), and breakup collision. We consider both the impact of water droplets and compound droplets (with one of two different-sized particles) on substrates of different wettabilities. The effects of inertia, surface tension, and adhesion between the substrate and the liquid droplet, and adhesion between the particle and the liquid droplet are considered to explain the different collision phenomena of compound droplets and reveal the evolution mechanism of the droplet morphologies in the experiments. Furthermore, the effects of the height from which the droplet is released and the contact angle of the substrate (i.e., its wettability) on the maximum spreading diameter and maximum jet height of the droplet are presented quantitatively. The effect of the size of the particle within the compound droplet and the substrate contact angle on the dynamic behavior of the compound droplet subject to impact with the substrate is also described.
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Nguyen, Khanh P., and Truong V. Vu. "Collision Modes of Two Eccentric Compound Droplets." Processes 8, no. 5 (May 18, 2020): 602. http://dx.doi.org/10.3390/pr8050602.
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A compound droplet with its single inner droplet appears in a broad range of applications and has received much attention in recent years. However, the role of the inner droplet location on the dynamical behaviors of the compound droplet is still not completely understood. Accordingly, the present study numerically deals with the eccentricity of the compound droplet affecting its colliding behaviors with the other droplet in a simple shear flow. The solving method is a front-tracking technique that treats the droplet interface as connected elements moving on a rectangular fixed grid. Initially, two compound droplets assumed circular are placed at a distance symmetrically to the domain center and they come into contact, because of the shear flow, when time progresses. During the collision process, the inner droplet that is initially located at a distance to its outer droplet center circulates around this center. It is found that this rotation also contributes to the formation of the collision modes including the reversing, passing-over and merging ones. Starting from a passing-over mode, a transition to a reversing mode or a merging mode can appear when the inner droplets, in terms of their centroids, are closer than their outer droplets. However, the location of the inner droplet within the outer droplet only has an effect when the value of the Capillary number Ca is varied from 0.01 to 0.08. For Ca < 0.01 corresponding to the merging mode and Ca ≥ 0.16 corresponding to the passing-over mode, the inner droplet position has almost no impact on the collision behaviors of two compound droplets.
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Pronkina, Tatiana Vasilievna. "About the influence of the forces of interaction between the droplets on the dynamics of emulsion." Yugra State University Bulletin 15, no. 1 (December 9, 2019): 59–65. http://dx.doi.org/10.17816/byusu20190159-65.
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The dynamics of deposition of compound droplets of the emulsion under the action of gravity is investigated. The interaction of the droplet with its inclusion is taken into account. Axisymmetric and asymmetric problems of deposition of compound droplets are considered. Expressions for the relative and absolute velocities of the compound emulsion droplets are found. Based on numerical modeling, the trajectories of the relative and absolute motion of the droplets are obtained.
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Sun, Meimei, Miao Zhao, and Wei Gao. "Hydrodynamics of Compound Droplet Flowing in the Curved Minichannel." Advances in Condensed Matter Physics 2019 (October 15, 2019): 1–11. http://dx.doi.org/10.1155/2019/5726974.
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Based on the volume of fluid (VOF) method, a theoretical model of compound droplet deformation in curved minichannel is developed. The effects of curved angle, continuous phase, radius ratio between the inner and integral droplets, and viscosity of the middle phase are examined to reveal the underlying mechanism of compound droplet deformation. The results indicate that the deformation process of the compound droplets in the curved minichannel can be divided into three stages, namely, the initial stage, the turning stage, and the adjustment stage. Both large curved angle and high capillary number of the continuous phase result in the large shear force and high eccentricity of the compound droplet. However, as the radius ratio increases, the influence of the inner droplet on the deformation of the compound droplet transits from enhancing to suppressing.
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Xue, Xinzhi, and Joseph Katz. "Formation of compound droplets during fragmentation of turbulent buoyant oil jet in water." Journal of Fluid Mechanics 878 (September 4, 2019): 98–112. http://dx.doi.org/10.1017/jfm.2019.645.
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Fragmentation of a vertical buoyant silicone oil jet injected into sugar water is elucidated by refractive index matching and planar laser-induced fluorescence. Compound droplets containing multiple water droplets, some with smaller oil droplets, form regularly at jet Reynolds numbers of $Re=1358$ and 2122 and persist for at least up to 30 nozzle diameters. In contrast, they rarely appear at $Re=594$. The origin of some of the encapsulated water droplets can be traced back to the entrained water ligaments during the initial roll-up of Kelvin–Helmholtz vortices. Analysis using random forest-based procedures shows that the fraction of compound droplets does not vary significantly with $Re$, but increases rapidly with droplet diameter, reaching 78 % for 2 mm droplets. Consequently, the size distributions of compound droplets have peaks that increase in magnitude and shift to a lower diameter with increasing $Re$. On average, the interior pockets raise the oil–water interfacial area by 15 %, increasing with diameter and axial location. Also, while the oil droplets are deformed by the jet’s shear field, the interior interfaces remain nearly spherical, consistent with prior studies of the deformation of isolated compound droplets for relevant capillary numbers and viscosity ratio.
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Ma, Zeyao, Shuai Zhang, Bo Wang, Qingquan Liu, and Xiaodong Chen. "Deformation characteristics of compound droplets with different morphologies during transport in a microchannel." Physics of Fluids 35, no. 4 (April 2023): 042003. http://dx.doi.org/10.1063/5.0146560.
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A numerical investigation of the deformation of compound microdroplets transported inside a circular microchannel is described in this article. Two droplet morphologies are considered (shell-core and Janus), which correspond to nonequilibrium and equilibrium states, respectively, based on the balancing of the three interfacial tensions at the triple line. Numerical simulations coupled with a three-phase volume-of-fluid method are performed on axisymmetric models to consider both the absence and presence of a triple line. In addition to adaptive mesh refinement on the interfaces, topology-oriented refinement is used to resolve thin films between the shell and core droplets. After experimental validation, the effects of flow rates, physical properties, and confinement conditions are considered. In the reference frame of the droplets, there are five inner vortexes inside the shell-core droplet, while only three are present inside the Janus droplet, the same as single-phase droplets. For shell-core droplets, the aspect ratio of the shell droplet decreases with the capillary number of the continuous phase and droplet sizes, while sudden jumps are identified when the thin film forms between the shell and core interfaces. Conversely, the aspect ratio of the core droplet increases and then decreases when the shape of the core droplets is influenced by the flow and space confinements. With Janus droplets, the aspect ratio decreases with the capillary number. The axial length of the front portion decreases with the capillary number and then reaches a plateau with small variations, while that of the rear portion increases nearly linearly.
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Suzuki, Toyoko, Yunfeng Li, Albert Gevorkian, and Eugenia Kumacheva. "Compound droplets derived from a cholesteric suspension of cellulose nanocrystals." Soft Matter 14, no. 47 (2018): 9713–19. http://dx.doi.org/10.1039/c8sm01716f.
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Compound Janus droplets were generated using microfluidic emulsification of the cholesteric suspension of cellulose nanocrystals and mineral oil. The capability to fine-tune droplet composition and the shape of the cholesteric phase is shown. The droplets were used to generate cholesteric microgels with non-conventional shapes.
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Ghaznavi, Amirreza, Yang Lin, Mark Douvidzon, Adam Szmelter, Alannah Rodrigues, Malik Blackman, David Eddington, et al. "A Monolithic 3D Printed Axisymmetric Co-Flow Single and Compound Emulsion Generator." Micromachines 13, no. 2 (January 26, 2022): 188. http://dx.doi.org/10.3390/mi13020188.
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We report a microfluidic droplet generator which can produce single and compound droplets using a 3D axisymmetric co-flow structure. The design considered for the fabrication of the device integrated a user-friendly and cost-effective 3D printing process. To verify the performance of the device, single and compound emulsions of deionized water and mineral oil were generated and their features such as size, generation frequency, and emulsion structures were successfully characterized. In addition, the generation of bio emulsions such as alginate and collagen aqueous droplets in mineral oil was demonstrated in this study. Overall, the monolithic 3D printed axisymmetric droplet generator could offer any user an accessible and easy-to-utilize device for the generation of single and compound emulsions.
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Weyer, Floriane, Marouen Ben Said, Johannes Hötzer, Marco Berghoff, Laurent Dreesen, Britta Nestler, and Nicolas Vandewalle. "Compound Droplets on Fibers." Langmuir 31, no. 28 (July 8, 2015): 7799–805. http://dx.doi.org/10.1021/acs.langmuir.5b01391.
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Ruehl, C. R., P. Y. Chuang, and A. Nenes. "Aerosol hygroscopicity at high (99 to 100%) relative humidities." Atmospheric Chemistry and Physics Discussions 9, no. 4 (July 24, 2009): 15595–640. http://dx.doi.org/10.5194/acpd-9-15595-2009.
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Abstract. The hygroscopicity of an aerosol largely determines its influence on climate and, for smaller particles, atmospheric lifetime. While much aerosol hygroscopicity data is available at lower relative humidities (RH) and under cloud formation conditions (RH>100%), relatively little data is available at high RH (99.2 to 99.9%). We measured the size of droplets at high RH that had formed on particles composed of one of seven compounds with dry diameters between 0.1 and 0.5 μm, and calculated the hygroscopicity of these compounds. We use a parameterization of the Kelvin term, in addition to a standard parameterization (κ) of the Raoult term, to express the hygroscopicity of surface-active compounds. For inorganic compounds, hygroscopicity could reliably be predicted using water activity data and assuming a surface tension of pure water. In contrast, most organics exhibited a slight to mild increase in hygroscopicity with droplet diameter. This trend was strongest for sodium dodecyl sulfate (SDS), the most surface-active compound studied. The results suggest that partitioning of surface-active compounds away from the bulk solution, which reduces hygroscopicity, dominates any increases in hygroscopicity due to reduced surface tension. This is opposite to what is typically assumed for soluble surfactants. Furthermore, we saw no evidence that micellization limits SDS activity in micron-sized solution droplets, as observed in macroscopic solutions. These results suggest that while the high-RH hygroscopicity of inorganic compounds can be reliably predicted using readily available data, surface-activity parameters obtained from macroscopic solutions with organic solutes may be inappropriate for calculations of the hygroscopicity of micron-sized droplets.
Dissertations / Theses on the topic "Compound droplets"
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Black, James Aaron. "Compound droplets for lab-on-a-chip." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54947.
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The development of a novel method of droplet levitation to be employed in lab-on-a-chip (LOC) applications relies upon the mechanism of thermocapillary convection (due to the temperature dependence of surface tension) to drive a layer of lubricating gas between droplet and substrate. The fact that most droplets of interest in LOC applications are aqueous in nature, coupled with the fact that success in effecting thermocapillary transport in aqueous solutions has been limited, has led to the development of a technique for the controlled encapsulation of water droplets within a shell of inert silicone oil. These droplets can then be transported, virtually frictionlessly, resulting in ease of transport due to the lack of friction as well as improvements in sample cross-contamination prevention for multiple-use chips. Previous reports suggest that levitation of spherical O(nL)-volume droplets requires squeezing to increase the apparent contact area over which the pressure in the lubricating layer can act allowing sufficient opposition to gravity. This research explores thermocapillary levitation and translation of O(nL)-volume single-phase oil droplets; generation, capture, levitation, and translation of O(nL)-volume oil-encapsulated water droplets to demonstrate the benefits and applicability to LOC operations.
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Qu, Xiaofeng. "Dynamics of Compound Droplets via 3D Spectral Boundary Elements." Thesis, North Dakota State University, 2013. https://hdl.handle.net/10365/27008.
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Compound droplets raise great interests due to their applications in the pharmaceutical, cosmetic, and food industry. In spite of the growing demand of theoretical investigation of dynamics of compound droplets from those applications, very limited effort has been contributed in the analytical and/or numerical study of them. In this work, a 3D spectral boundary element method is employed to investigate the dynamics of compound droplets for both concentric and eccentric configurations. A comprehensive investigation has been carried out on the influences of the relative droplet size, relative surface tensions on the two interfaces, relative viscosities of the fluids, and the initial location of the inner droplet, on the deformation, migration, and stability of compound droplets. Two mechanisms of droplet breakup have been observed: (a) the contact of the outer and inner interface and (b) the instability of the inner droplet.Department of Energy
National Science Foundation
ND EPSCoR
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Farhan, Noor M. "Multiphase Droplet Interactions with a Single Fiber." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/5937.
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Abstract
Multiphase Droplet Interactions with a Single Fiber
By: Noor M. Farhan
A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.
Virginia Commonwealth University, 2019
Director: Hooman V. Tafreshi,
Professor, Department of Mechanical and Nuclear Engineering
Formulating the physics of droplet adhesion to a fiber is interesting intellectually and important industrially. A typical example of a droplet–fiber system in nature is the dew droplets on spider webs, where droplets first precipitate and grow on the fibers, but they eventually fall when they become too heavy. Obviously, quantifying the force of adhesion between a droplet and a fiber is crucial in designing fog harvesting devices or manufacturing filtration media for liquid–gas or liquid–liquid separation, among many other industrial applications. This study is aimed at developing a mathematical framework for the mechanical forces between a droplet and a fiber in terms of their physical and wetting properties. To this end, a series of experiments were conducted to detach ferrofluid droplets of varying volumes from fibers with different diameters and Young–Laplace contact angles (YLCAs) in a controlled magnetic field. The force of detachment was measured using a sensitive scale and used along with the results of numerical simulations to develop a semi-analytical expression for the force required to detach a droplet from a fiber. This universally-applicable expression allows one to predict the force detachment without the need to run an experiment or a computer simulation.
This work also reports on the use of magnetic force to measure the force of detachment for nonmagnetic droplets for the first time. This is accomplished by adding a small amount of a ferrofluid to the original nonmagnetic droplet to create a compound droplet with the ferrofluid nesting inside or cloaking the nonmagnetic droplet. The ferrofluid is then used to induce a body force to the resulting compound droplet and thereby detach it from the fiber. The recorded detachment force is used directly (the case of nesting ferrofluid) or after scaling (the case of cloaking ferrofluid) to obtain the force of detachment for the original nonmagnetic droplet. The accuracy of these measurements was examined through comparison with numerical simulations as well as available experimental data in the literature. In addition, a simple method is developed to directly measure the intrinsic contact angle of a fiber (i.e., Young–Laplace Contact angle of the fiber material) with any arbitrary liquid. It is shown that the intrinsic contact angle of a fiber can be obtained by simply measuring the angle between the tangent to the fiber surface and the tangent to the droplet at the contact line, if the droplet possesses a clamshell conformation and is viewed from the longitudinal direction. The novelty of the proposed method is that its predictions are not affected by the volume of the droplet used for the experiment, the wettability of the fiber, the surface tension of the liquid, or the magnitude of the body force acting on the droplet during the experiment.
Also, a liquid droplet interaction with granular coatings is simulated and the droplet apparent contact angle (ACA) and the transition from Cassie (fully dry) to Wenzel (fully wet) state as a function to the roughness wavelength have been studied. For a fixed droplet volume, two different granular coatings have been used, spherical and hemispherical bumps. It is demonstrated that the chemistry (YLCA) and geometrical parameters for the granular microtexture play an important effect on the droplet ACA and its transition from Cassie to Wenzel state.
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Theberge, Ashleigh Brooks. "Droplet-based microfluidics for chemical synthesis and integrated analysis." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609687.
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Wang, Miao. "Study of Volatile Organic Compounds (VOC) in the cloudy atmosphere : air/droplet partitioning of VOC." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC080.
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Les composés organiques volatils (COV), les hydrocarbures saturés, insaturés et autres hydrocarbures substitués, jouent un rôle majeur dans la chimie atmosphérique. Ils sont principalement émis par des sources anthropiques et biogéniques dans l'atmosphère; ils sont également transformés in situ par des réactions chimiques, et plus spécifiquement par photo-oxydation conduisant à la formation d'ozone (O3) et d'aérosol organique secondaire (SOA). En modifiant la fraction organique des particules d'aérosol, les COV modifient l'équilibre radiatif de la Terre par un effet direct (absorption et diffusion du rayonnement solaire) ou par un effet indirect en altérant les propriétés microphysiques des nuages. Ils présentent également un effet direct sur la santé humaine et l'environnement. Au cours de leur transport atmosphérique, les COV et leurs produits d'oxydation, les composés organiques volatils oxygénés (OVOC), peuvent se répartir entre les phases gazeuses et aqueuses en fonction de leur solubilité. Les nuages ont un effet significatif sur la chimie troposphérique en redistribuant les traces de constituants entre les phases et en fournissant de l'eau liquide dans laquelle la chimie de la phase aqueuse peut avoir lieu. En effet, pendant la durée de vie des nuages, les composés chimiques et notamment les COV se transforment efficacement car les nuages favorisent le développement d'une «chimie multiphasique». Cette dernière présente plusieurs particularités. Premièrement, les processus photochimiques à l'intérieur des gouttelettes sont importants dans la transformation des composés chimiques. Deuxièmement, les réactions chimiques aqueuses sont efficaces et peuvent être plus rapides que les réactions équivalentes en phase gazeuse. Cela peut être lié à la présence d'oxydants puissants tels que le peroxyde d'hydrogène H2O2 ou les ions métalliques de transition (TMI), qui participent à la formation de radicaux tels que les radicaux hydroxyles (HO •) qui favorisent les processus d'oxydation. De plus, la présence de micro-organismes viables a été mise en évidence et a montré sa participation aux transformations des espèces chimiques. Enfin, ces transformations dans les nuages sont également fortement perturbées par des processus microphysiques qui contrôlent la formation, la durée de vie et dissipation des nuages. Ces processus redistribueront les espèces chimiques entre les différents réservoirs (eau de nuages, pluie, phase particulaire, phase gazeuse et phase de glace solide). Dans ce cadre, la transformation des COV dans le milieu nuageux peut conduire à la production de composés secondaires contribuant à la formation de SOA, appelés «nuage aqSOA». Cette masse d'aérosol organique secondaire produite pendant la durée de vie du nuage pourrait expliquer en partie l'ubiquité des petits acides dicarboxyliques et céto et des composés de haut poids moléculaire mesurés dans les particules d'aérosol, l'eau de brouillard, l'eau de nuage ou l'eau de pluie à de nombreux endroits, car ils n'ont ni sources d'émission directe ni aucune source importante identifiée en phase gazeuse. Cette masse d'aqSOA reste en phase particulaire après évaporation des nuages impliquant une modification des propriétés (micro) physiques et chimiques des particules d'aérosol (taille des particules, composition chimique, morphologie). Ceci conduit à des modifications de leurs impacts sur les cycles consécutifs de nuages ou de brouillard (effets indirects des aérosols) et de leurs interactions avec les rayonnements entrants par diffusion / absorption (effet direct des aérosols). (...)Volatile Organic Compounds (VOC), including saturated, unsaturated, and other substituted hydrocarbons, play a major role in atmospheric chemistry. They are primarily emitted by anthropogenic and biogenic sources into the atmosphere; they are also transformed in situ by chemical reactions, and more specifically, by photo-oxidation leading to the formation of ozone (O3) and Secondary Organic Aerosol (SOA). By altering the organic fraction of aerosol particles, VOC modify the Earth’s radiative balance through a direct effect (absorption and scattering of solar radiation) or through indirect effect by altering cloud microphysical properties. They also present a direct effect on human health and on the environment.During their atmospheric transport, VOC and their oxidation products, Oxygenated Volatile Organic Compounds (OVOC), may partition between the gaseous and aqueous phases depending on their solubility. Clouds have a significant effect on tropospheric chemistry by redistributing trace constituents between phases and by providing liquid water in which aqueous phase chemistry can take place. Indeed, during the cloud lifetime, chemical compounds and particularly VOC are efficiently transformed since clouds favor the development of complex “multiphase chemistry”. The latter presents several particularities. First, photochemical processes inside the droplets are important in the transformation of chemical compounds. Second, aqueous chemical reactions are efficient and can be faster than the equivalent reactions in the gas phase. This can be related to the presence of strong oxidants such as hydrogen peroxide H2O2 or Transition Metal Ions (TMI), which participate in the formation of radicals such as hydroxyl radicals (HO•) that favor oxidation processes. Furthermore, the presence of viable microorganisms has been highlighted and shown to participate in transformations of the chemical species. Finally, these transformations in clouds are also strongly perturbed by microphysical processes that control formation, lifetime and dissipation of clouds. These processes will redistribute the chemical species between the different reservoirs (cloud water, rain, particle phase, gaseous phase, and solid ice phase). In this frame, the transformation of VOC in the cloud medium can lead to the production of secondary compounds contributing to SOA formation, reported as “cloud aqSOA”. This secondary organic aerosol mass produced during the cloud lifetime could explain in part the ubiquity of small dicarboxylic and keto acids and high molecular-weight compounds measured in aerosol particles, fog water, cloud water, or rainwater at many locations, as they have neither substantial direct emission sources nor any identified important source in the gas phase. This aqSOA mass stays in the particle phase after cloud evaporation implying a modification of the (micro)physical and chemical properties of aerosol particles (particle size, chemical composition, morphology). This leads to modifications of their impacts on consecutive cloud or fog cycles (aerosol indirect effects) and of their interactions with incoming radiation by scattering/absorbing (aerosol direct effect). (...)
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Gidda, Satinder K., Samantha C. Watt, Jillian Collins-Silva, Aruna Kilaru, Vincent Arondel, Olga Yurchenko, Patrick J. Horn, et al. "Lipid Droplet-Associated Proteins (ldaps) Are Involved in the Compartmentalization of Lipophilic Compounds in Plant Cells." Digital Commons @ East Tennessee State University, 2013. https://doi.org/10.4161/psb.27141.
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While lipid droplets have traditionally been considered as inert sites for the storage of triacylglycerols and sterol esters, they are now recognized as dynamic and functionally diverse organelles involved in energy homeostasis, lipid signaling, and stress responses. Unlike most other organelles, lipid droplets are delineated by a half-unit membrane whose protein constituents are poorly understood, except in the specialized case of oleosins, which are associated with seed lipid droplets. Recently, we identified a new class of lipid-droplet associated proteins called LDAPs that localize specifically to the lipid droplet surface within plant cells and share extensive sequence similarity with the small rubber particle proteins (SRPPs) found in rubber-accumulating plants. Here, we provide additional evidence for a role of LDAPs in lipid accumulation in oil-rich fruit tissues, and further explore the functional relationships between LDAPs and SRPPs. In addition, we propose that the larger LDAP/SRPP protein family plays important roles in the compartmentalization of lipophilic compounds, including triacylglycerols and polyisoprenoids, into lipid droplets within plant cells. Potential roles in lipid droplet biogenesis and function of these proteins also are discussed.
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Asa-Awuku, Akua Asabea. "Characterizing water-soluble organic aerosol and their effects on cloud droplet formation: Interactions of carbonaceous matter with water vapor." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22658.
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Aerosols have significant impacts on earth's climate and hydrological cycle. They can directly reflect the amount of incoming solar radiation into space; by acting as cloud condensation nuclei (CCN), they can indirectly impact climate by affecting cloud albedo. Our current assessment of the interactions of aerosols and clouds is uncertain and parameters used to estimate cloud droplet formation in global climate models are not well constrained. Organic aerosols attribute much of the uncertainty in these estimates and are known to affect the ability of aerosol to form cloud droplets (CCN Activity) by i) providing solute, thus reducing the equilibrium water vapor pressure of the droplet and ii) acting as surfactants capable of depressing surface tension, and potentially, growth kinetics. My thesis dissertation investigates various organic aerosol species (e.g., marine, urban, biomass burning, Humic-like Substances). An emphasis is placed on the water soluble components and secondary organic aerosols (SOA). In addition the sampled organic aerosols are acquired via different media; directly from in-situ ambient studies (TEXAQS 2006) environmental chamber experiments, regenerated from filters, and cloud water samples. Novel experimental methods and analyses to determine surface tension, molar volumes, and droplet growth rates are presented from nominal volumes of sample. These key parameters for cloud droplet formation incorporated into climate models will constrain aerosol-cloud interactions and provide a more accurate assessment for climate prediction.
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Gustavsson, Joel. "Reactions in the Lower Part of the Blast Furnace with Focus on Silicon." Doctoral thesis, Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-59.
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Iyer, Chitra C. "The Role of Muscle and Nerve in Spinal Muscular Atrophy." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1451568269.
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Chen, Cheng-Wen, and 陳正文. "Heating and Micro-Explosion of Compound Droplets." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/99663209639170532683.
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碩士國立成功大學
機械工程學系碩博士班
93
A compound drop, composed of a fuel shell and a water core, was suspended and heated to micro-explosion. Three ambient temperatures, namely, 300 oC, 400 oC, and 500 oC and two fuels, namely diesel and n-hexadecane, were tested. The heating process was recorded by a high-speed video system, and the time at temperature of the micro-explosion were measured. The experimental results on compound drops were also compared with the micro-explosion of a heated emulsified W/O diesel-water drop. The micro-explosion of a heated compound drop was classified as either a indirect micro-explosion, if there were quite a few bubbles generated at the shell-core interface before the explosion, or a direct micro-explosion, if few or no bubble could be seen before the explosion. At an ambient temperature of 400 oC or 500 oC, the micro-explosion time was observed to increase with the micro-explosion temperature; but this trend was not as obvious at 300 oC ambient temperature. The intensity of the micro-explosion rose as the micro-explosion time lengthened, because the accumulation of thermal energy within the over-saturated water core drop grew to a higher extent. However, the size of the core water drop was not seen to influence either the micro-explosion time or micro-explosion temperature. Compared with pure n-hexadecane and pure water, the impurities or microscopic air bubbles in diesel and dyed water enhanced nonhomogenous nucleation and thus more steam bubbles were produced before micro-explosion. Furthermore, contrary to the intense micro-explosion of a compound drop, a heated emulsified diesel-water drop generally expanded, and followed by squirting of steam to relieve the pressure within the expanded drop. The distributed microscopic water drops in an emulsified drop acted as nonhomogeneous nucleation sites and made an overall micro-explosion improbable.
Book chapters on the topic "Compound droplets"
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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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Mucha, Eike, Daniel Thomas, Maike Lettow, Gerard Meijer, Kevin Pagel, and Gert von Helden. "Spectroscopy of Small and Large Biomolecular Ions in Helium-Nanodroplets." In Topics in Applied Physics, 241–80. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94896-2_6.
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AbstractA vast number of experiments have now shown that helium nanodroplets are an exemplary cryogenic matrix for spectroscopic investigations. The experimental techniques are well established and involve in most cases the pickup of evaporated neutral species by helium droplets. These techniques have been extended within our research group to enable nanodroplet pickup of anions or cations stored in an ion trap. By using electrospray ionization (ESI) in combination with modern mass spectrometric methods to supply ions to the trap, an immense variety of mass-to-charge selected species can be doped into the droplets and spectroscopically investigated. We have combined this droplet doping methodology with IR action spectroscopy to investigate anions and cations ranging in size from a few atoms to proteins that consist of thousands of atoms. Herein, we show examples of small complexes of fluoride anions (F−) with CO2 and H2O and carbohydrate molecules. In the case of the small complexes, novel compounds could be identified, and quantum chemistry can in some instances quantitatively explain the results. For biologically relevant complex carbohydrate molecules, the IR spectra are highly diagnostic and allow the differentiation of species that would be difficult or impossible to identify by more conventional methods.
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Bomhard, Ernst, Georg Luckhaus, Manfred Marsmann, and Andreas Zywietz. "Induction of Hyaline Droplet Accumulation in Renal Cortex of Male Rats by Aromatic Compounds." In Nephrotoxicity, 551–56. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4757-2040-2_84.
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Cadle, R. D., and R. C. Robbins. "Kinetics of the Reaction Between Ammonia and Sulfuric Acid Droplets in an Aerosol." In Atmospheric Chemistry of Chlorine and Sulfur Compounds: Proceedings of a Symposium Held at the Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio, November 4-6, 1957, 113–14. Washington D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm003p0113.
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Zeinali, Shakiba, and Janusz Pawliszyn. "Application of SPME for Comprehensive Analysis of Aerosol Samples." In Evolution of Solid Phase Microextraction Technology, 602–10. The Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781839167300-00602.
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The importance of comprehensive investigation of aerosol samples relies on the fact that some portions of analytes can be adsorbed on the particles/droplets and for full characterization, study of particle/droplet-bound compounds as well as free, gas-phase ones is required. Among various microextraction techniques, needle-trap devices (NTD) have the capability of trapping particles/droplets and extracting gaseous compounds, simultaneously. However, the filtration efficiency of sorbent-packed NTD can be low which can be improved by adding a filter. In this chapter, the investigation of aerosol samples using filter-incorporated NTD is explained. The application of the device for the study of various aerosol samples such as breath composition, air pollution, and sprays is described. From the reported results from this area, it is shown that free and total concentrations of analytes can vary significantly, depending on the physicochemical properties of the analytes and characteristics of the sample. The results from critical aerosol samples (including breath samples and air pollution) revealed that less-volatile and polar compounds have higher tendencies to remain attached/adsorbed on the particles/droplets. It can be concluded that when only the gas-phase is studied in aerosol samples, a portion of analytes can remain hidden and their related information can be lost from results.
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"Organometallic Vapor Phase and Droplet Heteroepitaxy of Quantum Structures." In InP and Related Compounds, 581–614. CRC Press, 2000. http://dx.doi.org/10.1201/9781482282986-19.
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Costa, Everton Ricardo Carneiro, Adriana Ferreira Souza, Galba Maria de Campos Takaki, and Rosileide Fontenele da Silva Andrade. "Bioemulsifier production by Penicillium Citrinum UCP 1183 and microstructural characterization of emulsion droplets." In CONNECTING EXPERTISE MULTIDISCIPLINARY DEVELOPMENT FOR THE FUTURE. Seven Editora, 2023. http://dx.doi.org/10.56238/connexpemultidisdevolpfut-168.
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Bioemulsifying compounds (BE) are biomolecules of high molecular weight produced by microorganisms and have as their main action the ability to emulsify and stabilize emulsions. In this context, the objective of this work was to investigate the potential of the fungus Penicillium citrinum in the production of bioemulsifier from substrates of renewable origin (milhocine and whey) and to characterize by optical microscopy the droplets of the emulsion formed. For this purpose, Penicillium citrinum was grown in sabouraud medium at 28ºC until the mycelial carpet was obtained. After growth, 20 8mm discs were used as inoculum in the production medium containing different concentrations of whey and cornocin determined by factorial design of 2 2. The statistical analysis of the residue concentrations was evaluated by the Pareto diagram, while the visualization of the microstructures of the emulsion droplets was visualized by optical microscopy with a 40x magnification. The results showed a maximum emulsification index of 95.8% and surface tension of 47.5 mN/m in condition 4 of the planning consisting of industrial residues (corn 5% and whey 5%). However, in all conditions of factorial design there was significant production of bioemulsifier. The Pareto diagram showed that the independent variable that most influenced the increase in the emulsification index was milhocin, followed by whey and its respective association. The type of emulsion formed was water-in-oil. The present study revealed that Penicillium citrinum has high biotechnological potential in the production of active biomolecule such as bioemulsifier (BE) produced from the metabolization of renewable industrial waste, suggesting potential use in cosmetics industries.
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Lynch, David K. "Cirrus: History and Definition." In Cirrus. Oxford University Press, 2002. http://dx.doi.org/10.1093/oso/9780195130720.003.0005.
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The most distinguishing physical property of cirrus (cirrostratus and cirrocumulus) is their composition. Cirrus are made predominantly or wholly of ice, whereas the majority of clouds (both in name and number) are composed of water droplets. That most clouds were composed of water droplets was probably well known to the ancients, who must surely have encountered fog in valleys and mountains. Yet the presence of ice in cirrus is not easily experienced in everyday life. To answer the question Who discovered that cirrus are made of ice? we have to trace developments in meteorology back almost 2500 years. Anaxagoras of Clazomenae (c. 500-428 B.C.) might have deduced that cirrus were made of ice. Using an inductive approach based on measurements and observations, Anaxagoras knew that clouds were made of water and that air was colder aloft. He believed that warm, moist air convected upward and that the water vapor cooled, condensed, and ultimately froze at great heights to become hail. We do not know if Anaxagoras considered cirrus explicitly because what little is left of his writings do not mention any cloud recognizable as cirrus (Gershenson and Greenberg 1964). Two thousand years passed before any substantial progress was made on cirrus. In 1637 Descartes (1596-1650) published Discours de la methode (Descartes 1637) in three parts: Dioptrics, Meteorology, and Geometry. In Dioptrics he set forth the law of refraction (Snell’s law) and in Meteorology he applied the law to the rainbows by performing numerical ray traces. Although he almost certainly knew the principle of minimum deviation, there is nothing in his writings that explicitly refers to it. In the ninth discourse on Meteorology, Descartes conjectures that the common 22° halo was due to refraction through ice crystals. . . . around the heavenly bodies there sometimes appear certain circles . . . they are round . . . and always surround the sun or some other heavenly body . . . they are colored, which shows that there is refraction. But the circles are never seen where it rains, which shows that they are not caused by the refraction which occurs in drops of water or in hail, but by that which is caused in those small little stars of transparent ice . . . those that we have observed most often have had their diameters at around 45° . . . (Olscamp 1965) . . .
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Pop, Laura-Ancuta, Oana Zanoaga, Paul Chiroi, Andreea Nutu, Schuyler S. Korban, Cristina Stefan, Alexandru Irimie, and Ioana Berindan-Neagoe. "Microarrays and NGS for Drug Discovery." In Drug Design - Novel Advances in the Omics Field and Applications. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96657.
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Novel technologies and state of the art platforms developed and launched over the last two decades such as microarrays, next-generation sequencing, and droplet PCR have provided the medical field many opportunities to generate and analyze big data from the human genome, particularly of genomes altered by different diseases like cancer, cardiovascular, diabetes and obesity. This knowledge further serves for either new drug discovery or drug repositioning. Designing drugs for specific mutations and genotypes will dramatically modify a patient’s response to treatment. Among other altered mechanisms, drug resistance is of concern, particularly when there is no response to cancer therapy. Once these new platforms for omics data are in place, available information will be used to pursue precision medicine and to establish new therapeutic guidelines. Target identification for new drugs is necessary, and it is of great benefit for critical cases where no alternatives are available. While mutational status is of highest importance as some mutations can be pathogenic, screening of known compounds in different preclinical models offer new and quick strategies to find alternative frameworks for treating more diseases with limited therapeutic options.
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Whiteman, C. David. "Clouds and Fogs." In Mountain Meteorology. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195132717.003.0014.
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Clouds are visual indicators of physical processes taking place in the atmosphere. They provide information about winds, stability, moisture content, and traveling weather systems that can be used in short-term (several hour) and long-term (24-36-hour) weather forecasts and in field assessments of weather conditions. Most clouds form when moist air is lifted and cooled. Lifting occurs when air rises over low pressure areas, is carried up inclined frontal surfaces, is carried upward by convective currents that originate at the heated ground, or flows over mountains. Clouds are classified according to their appearance (table 7.1) and the approximate altitude of their bases (table 7.2) following a simple scheme that was developed in 1803 by an English druggist, Luke Howard. This scheme can be expanded to describe certain clouds more precisely (World Meteorological Organization, 1987). The cloud types listed in table 7.1 are pictured in figure 7.1. The two basic cloud classifications are stratiform and cumuliform. Stratiform clouds form horizontal layers, with the horizontal dimension much greater than the vertical dimension. Cumuliform clouds, on the other hand, have roughly equal horizontal and vertical dimensions, giving them the appearance of a cotton ball. Stratiform clouds are given the stem name stratus, and cumuliform clouds are given the stem name cumulus.Stratiform and cumuliform clouds are assigned to one of three height classifications: high, middle, or low. High clouds are composed of ice crystals rather than water droplets and are named using the prefix cirro- (cirrocumulus or cirrostratus). Clouds at midlevels, which may be composed of either water or ice particles, are given the prefix alto- (altocumulus or altostratus). Low clouds are given no prefix (stratus or cumulus). When a stratus deck is composed of an array of individual cumulus elements or lumps, the term stratocumulus is used. Cirrus are stringy or fibrous high clouds that are neither stratiform nor cumuliform. Towering cumulus extend through low and middle levels of the atmosphere. A thunderstorm cloud, called a cumulonimbus. extends through low, middle, and high levels of the atmosphere and is accompanied by lightning and showery precipitation. Clouds that bring widespread, light precipitation but not lightning, thunder, or hail are called nimbostratus.
Conference papers on the topic "Compound droplets"
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Weyer, Floriane, Marjorie Lismont, Laurent Dreesen, and Nicolas Vandewalle. "Poster: Highly sophisticated compound droplets on fiber arrays." In 67th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2014. http://dx.doi.org/10.1103/aps.dfd.2014.gfm.p0049.
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Palaniappan, D. "Viscous Flows Involving a Liquid-Vapor Compound Droplet." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/fed-24942.
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Abstract Exact analytical solutions for steady-state axisymmetric creeping flows in and around a compound multiphase droplet are presented. The solutions given here explain the droplet fluid interactions in uniform and nonuniform flow fields. The compound droplet has a two-sphere geometry with the two spherical surfaces (of unequal radii) intersecting orthogonally. The surface tension forces are assumed to be sufficiently large so that the interfaces have uniform curvature. The singularity solutions for the uniform and paraboloidal flows in the presence of a compound droplet are derived using the method of reflections. The exact solutions for the velocity and pressure fields in the continuous and dispersed phases are given in terms of the fundamental singularities (Green’s functions) and their derivatives. It is found that flow fields and the drag forces depend on two parameters namely, the viscosity ratio and the radii ratio. In the case of paraboloidal flows, a single or a pair of eddies is noticed in the continuous phase for various values of these parameters. The eddies changes their size and shape if the size of the droplet is altered. These observations may be useful in the study of hydrodynamic interactions of compound droplets in complex situations. It is found that the Stokes resistance is greater when the liquid volume is large compared to the vapor volume in uniform flow. It is also noticed that the maximum value of the drag in paraboloidal flow depends on the viscosity ratio and significantly on the liquid volume in the dispersed phase. The exact solutions presented here may be useful for boundary integral formulations that are based on special kernels and also in validating numerical algorithms and codes on multiphase flow and droplet-fluid interactions.
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Wang, Ting, and Xianchang Li. "Simulation of Mist Film Cooling at Gas Turbine Operating Conditions." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90742.
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Air film cooling has been successfully used to cool gas turbine hot sections for the last half century. A promising technology is proposed to enhance air film cooling with water mist injection. Numerical simulations have shown that injecting a small amount of water droplets into the cooling air improves film-cooling performance significantly. However, previous studies were conducted at conditions of low Reynolds number, temperature, and pressure to allow comparisons with experimental data. As a continuous effort to develop a realistic mist film cooling scheme, this paper focuses on simulating mist film cooling under typical gas turbine operating conditions of high temperature and pressure. The mainstream flow is at 15 atm with a temperature of 1561K. Both 2-D and 3-D cases are considered with different hole geometries on a flat surface, including a 2-D slot, a simple round hole, a compound-angle hole, and fan-shaped holes. The results show that 10%–20% mist (based on the coolant mass flow rate) achieves 5%–10% cooling enhancement and provides an additional 30–68K adiabatic wall temperature reduction. Uniform droplets of 5 to 20 μm are used. The droplet trajectories indicate the droplets tend to move away from the wall, which results in a lower cooling enhancement than under low pressure and temperature conditions. The commercial software Fluent (v. 6.2.16) is adopted in this study, and the standard k-ε model with enhanced wall treatment is adopted as the turbulence model.
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Steele, Adam, Stephen Moran, Andrew Cannon, William King, Ilker Bayer, and Eric Loth. "Conformal Nanocomposite Spray Coatings on Micro-Patterned Surfaces for Superhydrophobicity." In ASME 2008 Fluids Engineering Division Summer Meeting collocated with the Heat Transfer, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/fedsm2008-55051.
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A novel conformal coating process is presented to transform surfaces with micro-morphology into hierarchical superhydrophobic surfaces using one-step, wet chemical spray casting. The nanocomposite coating consists of zinc oxide nanoparticles and organomodified polydimethylsiloxane (PDMS), also known as organosilane quaternary nitrogen compound. The coating is applied to a micro-patterned PDMS substrate of cylindrical microposts to create a stable superhydrophobic state for water droplets. An explanation for the non-wetting performance of the conformal nanocomposite coatings compared to previous non-conformal surfaces is also proposed.
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Waez, Mir Seliman, Steven J. Eckels, and Christopher M. Sorensen. "Low-Cost Particulate Detection in Bleed Air." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10460.
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Abstract Bleed air is brought into aircraft cabins in order to maintain the quality of the air for passenger and crew health and comfort. The bleed air can be contaminated by oil due to oil seal leaks in the compressor which have been reported randomly and generated significant public interest. Previous studies have measured the particulate size distribution in the bleed air entering the cabin, but never distinguished the type and material of the particulate matter (PM). The particulates could be potentially hazardous oil droplets from the oil seal leaks, water droplets due the presence of fog generated by the cooling system, and so on. In this study we propose a novel technique using light scattering technology to distinguish between contaminant types. This technique uses size and complex index of refraction as the measure. Since each material has a distinct index of refraction, by determining the index of refraction, our proposed low-cost detector could distinguish the compound in the aerosol as well as determine the particle size simultaneously.
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Sugai, T., T. Abe, and Y. Minamitani. "Improvement of efficiency for decomposition of organic compound in water using pulsed streamer discharge in air with water droplets by increasing of residence time." In 2009 IEEE Pulsed Power Conference (PPC). IEEE, 2009. http://dx.doi.org/10.1109/ppc.2009.5386130.
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Fang, M., S. Chandra, and C. B. Park. "Building Vertical Walls by Deposition of Molten Metal Droplets." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-82006.
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Experiments were conducted to determine conditions under which good metallurgical bonding was achieved in vertical walls composed of multiple layers of droplets that were fabricated by depositing tin droplets layer by layer. Molten tin droplets (0.75 mm diameter) were deposited using a pneumatic droplet generator on an aluminum substrate. The primary parameters varied in experiments were those found to most affect bonding between droplets on different layers: droplet temperature (varied from 250°C to 325°C) and substrate temperature (varied from 100°C to 190°C). Considering the cooling rate of droplet is much faster than the deposition rate previous deposition layer cooled down too much that impinging droplets could only remelt a thin surface layer after impact. Assuming that remelting between impacting droplets and the previous deposition layer is a one-dimensional Stefan problem with phase change an analytical solution can be found and applied to predict the minimum droplet temperature and substrate temperature required for local remelting. It was experimentally confirmed that good bonding at the interface of two adjacent layers could be achieved when the experimental parameters were such that the model predicted remelting.
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Ji, C. Y., and Y. Y. Yan. "A Molecular Dynamics Simulation of Droplets Merging in Mist Flow of Flow Boiling Microchannel." In ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2008. http://dx.doi.org/10.1115/icnmm2008-62120.
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The present paper is concerned with a molecular dynamics simulation of the behaviour of droplets merging in mist flow of flow boiling in microchannel. Two identical droplets were assigned in one simulation system and the process of their merging is investigated. The droplets are assumed to be composed of Lennards-Jones type molecules. Periodic boundary conditions are applied in three coordinate directions of a three-dimensional system, where there exist two liquid droplets and their vapour. The two droplets merge when they come within the prescribed small distance. The evolution of the merging process is simulated and presented. The merging of two droplets apart from each other at different initial distances is tested and the possible larger (or critical) non-dimensional distance, in which droplet merging can occur, is discussed. The evolution of the merging process is simulated numerically by employing the molecular dynamics (MD) method. In the present modelling, the molecules near the boundary of one liquid droplet thermally fluctuate into the range of attraction of the other droplet, forming a bridge to connect the two droplets. A dumbbell shape is then formed and thereafter an elliptic merged droplet. Eventually a larger merged spherical droplet appears in the system and is in equilibrium with its vapour phase. More realistic simulation system will be established to further the present preliminary results for application in mist flow of flow boiling in microchannel.
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Feng, Liyan, Zixin Wang, Ping Yi, Weixin Gong, Jingchen Cui, Lei Chen, Jiangping Tian, and Wuqiang Long. "Numerical Study on Evaporation of Lubricating Oil Droplets Under Natural Gas Engine Conditions." In ASME 2018 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icef2018-9639.
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The distribution of lubricating oil droplets in cylinder is one of main causes of abnormal combustion of natural gas engines. The evaporation of lubricating oil droplet is one of the key sub-processes controlling its auto-ignition event. The components of lubricating oil with different carbon number (16–50) shows significantly different evaporation and ignition characteristics from gasoline and diesel fuels. Even though there are many evaporation models focusing on the evaporation behaviors of multi-component droplets, most of them are limited to the liquid fuels, which are composed by more volatile hydrocarbons. Therefore, understanding the evaporation characteristics of lubricating oil droplets is very important for investigating the mechanism of abnormal combustion of natural gas engines. In this study, a multi-component evaporation model for lubricating oil was developed, which considers several key characteristics in the droplet evaporation process, including the finite heat conduction and limited mass diffusion in liquid phase, multi-component diffusion in gas phase, real vapor-liquid equilibrium at the droplet interface, as well as the nitrogen quantity dissolved in liquid phase. The simulation results by this model were compared with experimental results, and good agreements have been achieved. Then, this model was used to study the evaporation behaviors of different hydrocarbon droplets, including lubricating oil droplet. The influences of ambient temperatures and pressures, as well as methane concentration on evaporation characteristics (namely the heat up period, average evaporation rate, and droplet lifetime) were investigated. The results show that both heat up period and evaporation rate of lubricating oil droplets increase as the methane concentration increases. Besides, the droplet lifetime monotonically decreases as the ambient pressure decreases. This is different from the diesel and gasoline droplets, for which the effects of pressure on the droplet evaporation behaviors are depended on the ambient temperature.
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morqenstern, E., and H. Patscheke. "THE SECRETORY PATHWAY IN PLATELETS STUDIED BY CRYO-FIXATION." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643491.
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It is widely held, that the constituents packed in the a -granules are released by stimulated platelets via the surface connected system (SCS). By means of the fast-freezing and freeze substitution technique (which allow the investigation of membrane fusion) we found a secretory pathway in platelets (compound exocytosis) without an involvement of the SCS during the release of a-granules. To study the process of a-granule secretion human platelets concentrated in citrated blood plasm were stimulated with thrombin or collagen. 20 - 120 seconds after stimulation the platelets were rapidly frozen with a metal-mirror attachment to the KF 80 cryofixation unit (REICHERT-JUNG). Using plastic spacers droplets of the PRP were slammed against a copper block at 80 K at a rate of 0.2 m/sec. After cryofixation the specimens were transferred (in liquid nitrogen) into a Cs-auto cryosubstitution unit (REICHERT-JUNG). Cryosubstitution was programmed for 48h at 193 K in acetone with 4% osmium tetroxide. The temperature went automatically up to room temperature at a rate of 10 K/h. The specimens were embedded in araldite. The analysis of serial ultrathin sections of platelets in different phases of exocytosis revealed the following. a -granules in apposition showed different stages of swelling and dispersal of their electron dense matrix. Membrane appositions were also found between a -granules. The contraction of a sphere of microfilaments and microtubules during stimulation seemed to support this process. On the other hand this internal contraction prevented most of the a-granules from contacting with the plasmalemma. We observed fusion between swollen -granules in apposition and the plasmalemma and swollen and unswollen a -granules. Thus, large compound granules were formed frequently before fusion of the secretory organelles with the plasmalemma took place. These observations suggested that a -granules in stimulated platelets performed a compound exocytosis after swelling. The process seemed to start with the apposition of a -granule membranes to the plasmalemma. It cannot yet be answered whether the swelling of the granules is due to an osmotically driven influx of water or due to an influx after microfusion.Supported by DFG, Grant Mo 124/2-4
Reports on the topic "Compound droplets"
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Lawson. L51597 Feasibility Study of New Technology for Intake Air Filtration. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), June 1989. http://dx.doi.org/10.55274/r0010105.
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Inlet air filters are widely used to remove solids and liquid droplets from the ambient air before it enters the compressor of a gas turbine. Clean inlet air provides many advantages: Less corrosion of the compressor and of gas-path hot parts, such as the turbine, decreased compressor fouling, less erosion of the compressor bladeThese in turn prevent deterioration of output and heat rate, and reduce maintenance costs. Compressor fouling is caused by the ingestion of substances that deposit and adhere to blade surfaces, resulting in reduced aerodynamic efficiency and decreased available output. Air contamination could be significantly reduced by the use of more efficient air filtration systems, especially through the reduction of the quantity of smaller particles ingested. The consequent lower loss of output power and decreased cleaning efforts provide lower costs of operation and increased shaft power. This work was composed of three major efforts: 1) A literature search was performed to establish the state of the art for particle removal from gases, particularly by electrostatic precipitation, and to identify the leading vendors of the equipment-considering both experience and technical expertise. 2) Two chosen companies were visited to determine their technical capabilities as they apply to gas turbine inlet air filtration. 3) A representative gas turbine was specified by PRCI as being the equivalent of a GE Model 3002J turbine, with airflow of 91,200 acfm. A specification based upon that airflow was prepared and submitted to the two vendors. Each vendor prepared a proposal for a filter system compliant with the specification. The proposed air filtration equipment is sufficiently different from existing products that it was judged not beneficial to visit manufacturing facilities. Both vendors are reputable suppliers of air filtration equipment. This study is intended to provide definitive information relative to the use of new technology for air inlet filtration on gas turbines in gas pipeline pumping applications.