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In electrical insulation material designing, treeing is an electrical pre-breakdown marvel in strong protection. Treeing is a typical breakdown component and wellspring of electrical deficiencies in insulation of electrical applications protection. Moreover, water treeing is a diffuse part of the way conductive 3D crest-like a shape inside the utilized dielectrics in covered or water-drenched electrical applications. Nanotechnology techniques have been enhancing the dielectric strength performance with respect to traditional dielectrics. Therefore, this chapter discusses the treeing mechanisms in theoretical models for various nanodielectrics insulation materials. Water treeing in nanodielectrics is also addressed. Furthermore, this chapter contains forecast and recommendations to enhance insulation performance of electrical applications.


2020 ◽  
Vol 637 ◽  
pp. A18 ◽  
Author(s):  
Tony Bonnaire ◽  
Nabila Aghanim ◽  
Aurélien Decelle ◽  
Marian Douspis

Numerical simulations and observations show that galaxies are not uniformly distributed in the universe but, rather, they are spread across a filamentary structure. In this large-scale pattern, highly dense regions are linked together by bridges and walls, all of them surrounded by vast, nearly-empty areas. While nodes of the network are widely studied in the literature, simulations indicate that half of the mass budget comes from a more diffuse part of the network, which is made up of filaments. In the context of recent and upcoming large galaxy surveys, it becomes essential that we identify and classify features of the Cosmic Web in an automatic way in order to study their physical properties and the impact of the cosmic environment on galaxies and their evolution. In this work, we propose a new approach for the automatic retrieval of the underlying filamentary structure from a 2D or 3D galaxy distribution using graph theory and the assumption that paths that link galaxies together with the minimum total length highlight the underlying distribution. To obtain a smoothed version of this topological prior, we embedded it in a Gaussian mixtures framework. In addition to a geometrical description of the pattern, a bootstrap-like estimate of these regularised minimum spanning trees allowed us to obtain a map characterising the frequency at which an area of the domain is crossed. Using the distribution of halos derived from numerical simulations, we show that the proposed method is able to recover the filamentary pattern in a 2D or 3D distribution of points with noise and outliers robustness with a few comprehensible parameters.


Surfactants ◽  
2019 ◽  
pp. 130-155
Author(s):  
Bob Aveyard

The physical properties of solid/liquid interfaces are more diverse than those of liquid/fluid interfaces, and consequently the interactions giving rise to adsorption of surfactant or polymeric surfactant are more varied. Solid surfaces can be either hydrophilic or hydrophobic, the former being water-wetted and containing polar or ionogenic sites. Electrical charge at the solid surface is neutralized by ions in the inner and outer Helmholtz planes and in the diffuse part of the electrical double layer. Surface charge has a strong influence on adsorption of ionic surfactants. Standard free energies of surfactant adsorption are obtained by use of an appropriate adsorption isotherm such as the Stern–Langmuir equation. Micellar aggregates of various shapes and sizes can also form at solid/liquid interfaces.


2019 ◽  
Vol 626 ◽  
pp. A131 ◽  
Author(s):  
B. Mookerjea ◽  
G. Sandell ◽  
R. Güsten ◽  
D. Riquelme ◽  
H. Wiesemeyer ◽  
...  

Pillars and globules are the best examples of the impact of the radiation and wind from massive stars on the surrounding interstellar medium. We mapped the G287.84-0.82 cometary globule (with the Treasure Chest cluster embedded in it) in the South Pillars region of Carina (i) in [C II], 63 μm [O I], and CO(11–10) using the heterodyne receiver array upGREAT on SOFIA and (ii) in J = 2–1 transitions of CO, 13CO, C18O, and J = 3–2 transitions of H2CO using the APEX telescope in Chile. We used these data to probe the morphology, kinematics, and physical conditions of the molecular gas and the photon-dominated regions (PDRs) in G287.84-0.82. The velocity-resolved observations of [C II] and [O I] suggest that the overall structure of the pillar (with red-shifted photoevaporating tails) is consistent with the effect of FUV radiation and winds from η Car and O stars in Trumpler 16. The gas in the head of the pillar is strongly influenced by the embedded cluster, whose brightest member is an O9.5 V star, CPD −59°2661. The emission of the [C II] and [O I] lines peak at a position close to the embedded star, while all the other tracers peak at another position lying to the northeast consistent with gas being compressed by the expanding PDR created by the embedded cluster. The molecular gas inside the globule was probed with the J = 2–1 transitions of CO and isotopologs as well as H2CO, and analyzed using a non-local thermodynamic equilibrium model (escape-probability approach), while we used PDR models to derive the physical conditions of the PDR. We identify at least two PDR gas components; the diffuse part (~ 104 cm−3) is traced by [C II], while the dense (n ~ 2–8 × 105 cm−3) part is traced by [C II], [O I], and CO(11–10). Using the F = 2–1 transition of [13C II] detected at 50 positions in the region, we derived optical depths (0.9–5), excitation temperatures (80–255 K) of [C II], and N(C+) of 0.3–1 × 1019 cm−2. The total mass of the globule is ~1000 M⊙, about half of which is traced by [C II]. The dense PDR gas has a thermal pressure of 107–108 K cm−3, which is similar to the values observed in other regions.


2019 ◽  
Author(s):  
Terri-Leigh Stephen ◽  
Francesco Tamagnini ◽  
Judith Piegsa ◽  
Katherine Sung ◽  
Joshua Harvey ◽  
...  

AbstractAlzheimer’s disease (AD)-associated synaptic dysfunction drives the progression of pathology from its earliest stages. Aβ species, both soluble and in plaque deposits, have been causally related to the progressive, structural and functional impairments observed in AD. It is, however, still unclear how Aβ plaques develop over time and how they progressively affect local synapse density and turnover. Here we observed, in a mouse model of AD, that Aβ plaques grow faster in the earlier stages of the disease and if their initial area is > 500 µm2; this may be due to deposition occurring in the diffuse part of the plaque. In addition, synaptic turnover is higher in the presence of amyloid pathology and this is paralleled by a reduction in pre-but not post-synaptic densities. Plaque proximity does not appear to have an impact on synaptic dynamics. These observations indicate an imbalance in the response of the pre- and post-synaptic terminals and that therapeutics, alongside targeting the underlying pathology, need to address changes in synapse dynamics.


2019 ◽  
Vol 282 ◽  
pp. 02093
Author(s):  
Peter Juras

Advance in the numerical simulation models brings higher need for more accuracy outdoor boundary conditions - climate data sets. With influence of the urban heat islands, measured climate on the meadows, far from pawed surfaces creates uncertainty in the simulation. Another problem is the modelling of solar radiation impact on the surface temperatures. Solar radiation heats up the surface of the structure and increase the speed of vapor transport. To obtain correct results, global and diffuse solar radiation is needed in the HAM software. In this paper, influence of the diffuse part of solar radiation is analyzed. As it would be shown, correct modeling of the solar radiation, both global and diffuse is very important to reach good precision. This analysis is done in software WUFI Pro and compared with the experimental measurement of the wooden wall fragments.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
J. J. López-García ◽  
J. Horno ◽  
C. Grosse

The structure and differential capacitance of the diffuse part of the electric double layer at solid-electrolyte solution interfaces are examined using a theoretical model that takes into account the finite ion size by modeling the solution as a suspension of polarizable insulating spheres in water. This formalism is applied to binary and mixed electrolyte solutions using the “Boublik–Mansoori–Carnahan–Starling–Leland” (BMCSL) theory for the steric interactions among ions. It is shown that the ionic size differences have a strong bearing on the diffuse part of the electric double layer structure, as well as on the differential capacitance dependence on the surface potential for mixed electrolytes.


2018 ◽  
Vol 18 (2) ◽  
pp. 361-392 ◽  
Author(s):  
Flavia Smarrazzo

AbstractWe study the existence of measure-valued solutions for a class of degenerate elliptic equations with measure data. The notion of solution is natural, since it is obtained by a regularization procedure which also relies on a standard approximation of the datum μ. We provide partial uniqueness results and qualitative properties of the constructed solutions concerning, in particular, the structure of their diffuse part with respect to the harmonic-capacity.


2012 ◽  
Vol 701 ◽  
pp. 333-351 ◽  
Author(s):  
Ory Schnitzer ◽  
Ehud Yariv

AbstractWe analyse particle electrophoresis in the thin-double-layer limit for asymptotically large applied electric fields. Specifically, we consider fields scaling as ${\delta }^{\ensuremath{-} 1} $, $\delta ~(\ll \hspace *{-2pt}1)$ being the dimensionless Debye thickness. The dominant advection associated with the intense flow mandates a uniform salt concentration in the electro-neutral bulk. The $O({\delta }^{\ensuremath{-} 1} )$ large tangential fields in the diffuse part of the double layer give rise to a novel ‘surface conduction’ mechanism at moderate zeta potentials, where the Dukhin number is vanishingly small. The ensuing $O(1)$ electric current emerging from the double layer modifies the bulk electric field; the comparable $O(1)$ transverse salt flux, on the other hand, is incompatible with the nil diffusive fluxes at the homogeneous bulk. This contradiction is resolved by identifying the emergence of a diffusive boundary layer of $O({\delta }^{1/ 2} )$ thickness, resembling thermal boundary layers at large-Reynolds-number flows. The modified electric field within the bulk gives rise to an irrotational flow, resembling those in moderate-field electrophoresis. At leading order, the particle electrophoretic velocity is provided by Smoluchowski’s formula, describing linear variation with applied field.


2012 ◽  
Vol 18 ◽  
pp. 1068-1075 ◽  
Author(s):  
M. Chikh ◽  
A. Mahrane ◽  
M. Haddadi

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