723 research outputs found
Effective interactions and equilibrium configurations of colloidal particles on a sessile droplet
We study the free energy landscapes of a pair of submicron spherical
particles floating at the surface of a sessile droplet. The particles are
subjected to radial external forces resulting in a deformation of the droplet
shape relative to the reference shape of a spherical cap. This deformation
leads to tangential forces on the particles. For small deformations and for the
contact angle at the substrate being equal to , the
corresponding linearized Young-Laplace equation is solved analytically. The
solution is constructed by employing the method of images from electrostatics,
where each of the particles plays the role of a capillary monopole and the
substrate is replaced by a virtual drop with image charges and by imposing the
conditions of fixed droplet volume and vanishing total force on the droplet.
The substrate boundary conditions determine the signs of the image capillary
charges and therefore also the strength of the tangential forces on the
particles. In the cases of an arbitrary contact angle these forces
are calculated numerically by employing a finite element method to find the
equilibrium shape of the droplet for those configurations in which the
particles are close to the local free energy minima.Comment: 23 pages, 8 figure
Capillary interactions in Pickering emulsions
The effective capillary interaction potentials for small colloidal particles
trapped at the surface of liquid droplets are calculated analytically. Pair
potentials between capillary monopoles and dipoles, corresponding to particles
floating on a droplet with a fixed center of mass and subjected to external
forces and torques, respectively, exhibit a repulsion at large angular
separations and an attraction at smaller separations, with the latter
resembling the typical behavior for flat interfaces. This change of character
is not observed for quadrupoles, corresponding to free particles on a
mechanically isolated droplet. The analytical results for quadrupoles are
compared with the numerical minimization of the surface free energy of the
droplet in the presence of ellipsoidal particles.Comment: twocolumn, 8 pages, 3 figures, submitted to Phys. Rev.
Anthropocene history of rich fen acidification in W Poland: causes and indicators of change
In the time of the global climate crisis, it is vital to protect and restore peatlands to maintain their functioning as carbon sinks. Otherwise, their transformations may trigger a shift to a carbon source state and further contribute to global warming. In this study, we focused on eutrophication, which resulted in its transition from rich fen to poor fen conditions. The prior aim was to decipher how i) climate, ii) human, and iii) autogenic processes influenced the pathway of peatland changes in the last ca. 250 years. We applied a high-resolution palaeoecological analysis, based mainly on testate amoebae (TA) and plant macroremains. Our results imply that before ca. 1950 CE, dry shifts on the Kazanie fen were generally climate-induced. Later, autogenic processes, human pressure and climate warming synergistically affected the fen, contributing to its transition to poor fen within ca. 30 years. Its establishment not only caused changes in vegetation but also altered TA taxonomic content and resulted in a lower diversity of TA. According to our research M. patella is an incredibly sensitive testate amoeba that after ca. 200 years of presence, disappeared within 2 years due to changes in water and nutrient conditions. As a whole, our study provides a long-term background that is desired in modern conservation studies and might be used to define future restoration targets. It also confirms the already described negative consequences connected with the Anthropocene and not sustainable exploitation of nature.1. Introduction 2. Material and methods 2.1. State of art 2.1.1. Study site 2.1.2. Core retrieval and chronology 2.1.3. Plant macrofossils 2.2. Testate amoebae (TA) 2.3. Statistical analyses and visualization 3. Results and interpretation 3.1. Mire succession: plant macrofossils, testate amoebae, water table and conductivity 3.1.1. Phase I – rich fen; 91–35.5 cm; ca. 1767±45–1982±3 CE 3.1.2. Phase II – poor fen; 35.5–0 cm; ca. 1982±3–2017 CE 3.2. Non-Metric Multidimensional Scaling (NMDS) 4. Discussion 4.1. An abrupt rich to poor fen transition – causes of change 4.2. Quality of testate amoebae indicators of the rich-poor fen transformatio
Anthropocene history of rich fen acidification in W Poland: Causes and indicators of change
In the time of the global climate crisis, it is vital to protect and restore peatlands to maintain their functioning as carbon sinks. Otherwise, their transformations may trigger a shift to a carbon source state and further contribute to global warming. In this study, we focused on eutrophication, which resulted in its transition from rich fen to poor fen conditions. The prior aim was to decipher how i) climate, ii) human, and iii) autogenic processes influenced the pathway of peatland changes in the last ca. 250 years. We applied a high-resolution palaeoecological analysis, based mainly on testate amoebae (TA) and plant macroremains. Our results imply that before ca. 1950 CE, dry shifts on the Kazanie fen were generally climate-induced. Later, autogenic processes, human pressure and climate warming synergistically affected the fen, contributing to its transition to poor fen within ca. 30 years. Its establishment not only caused changes in vegetation but also altered TA taxonomic content and resulted in a lower diversity of TA. According to our research M. patella is an incredibly sensitive testate amoeba that after ca. 200 years of presence, disappeared within 2 years due to changes in water and nutrient conditions. As a whole, our study provides a long-term background that is desired in modern conservation studies and might be used to define future restoration targets. It also confirms the already described negative consequences connected with the Anthropocene and not sustainable exploitation of nature.1. Introduction 2. Material and methods 2.1. State of art 2.1.1. Study site 2.1.2. Core retrieval and chronology 2.1.3. Plant macrofossils 2.2. Testate amoebae (TA) 2.3. Statistical analyses and visualization 3. Results and interpretation 3.1. Mire succession: plant macrofossils, testate amoebae, water table and conductivity 3.1.1. Phase I – rich fen; 91–35.5 cm; ca. 1767±45–1982±3 CE 3.1.2. Phase II – poor fen; 35.5–0 cm; ca. 1982±3–2017 CE 3.2. Non-Metric Multidimensional Scaling (NMDS) 4. Discussion 4.1. An abrupt rich to poor fen transition – causes of change 4.2. Quality of testate amoebae indicators of the rich-poor fen transformatio
The integration of optical interconnections on ceramic substrates
High heat conductivity and high heat capacity make ceramic substrates indispensable to the manufacture of Multi-Chip Modules (MCM) and power electronics. In this paper a detailed description of the integration process of optical lines on to ceramic substrates is presented. The manufacturing of microgrooves in ceramic substrates and the process of integration of optical fibres and active elements is described. Coupling active elements to optical fibre is also presented. Through such an integrated optical line a 4 Gbps signal was transmitted. © 2016 Elsevier B.V. All rights reserved
Direct comparison of sterile neutrino constraints from cosmological data, <i>ν</i><sub><i>e</i></sub> disappearance data and <i>ν</i><sub><i>μ</i></sub>→ <i>ν</i><sub><i>e</i></sub> appearance data in a 3+1 model
Reply to ‘Reduction in grain pollen indicates population decline, but not necessarily Black Death mortality’
Impact of post-event avoidance behavior on commercial facilities sector venues-literature review.
The terrorist attacks of September 11, 2001 (9/11), focused a great deal of interest and concern on how individual and social perceptions of risk change behavior and subsequently affect commercial sector venues. Argonne conducted a review of the literature to identify studies that quantify the direct and indirect economic consequences of avoidance behaviors that result from terrorist attacks. Despite a growing amount of literature addressing terrorism impacts, relatively little is known about the causal relationships between risk perception, human avoidance behaviors, and the economic effects on commercial venues. Nevertheless, the technical and academic literature does provide some evidence, both directly and by inference, of the level and duration of post-event avoidance behaviors on commercial venues. Key findings are summarized in this Executive Summary. Also included as an appendix is a more detailed summary table of literature findings reproduced from the full report
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