408 research outputs found
Wettability between molten slag and dolomitic refractory
In the current study, the wettability between molten slag and dolomitic refractory materials used in the ladle during steel refining was investigated. The contact angle between molten slag and dolomitic substrate decreased with increasing temperature. The slag with lower basicity spread on the substrate more easily and penetrated deeper into the substrate. The penetration depth of slag into the refractory increased with the extension of holding time. The CaO in the refractory dissolved into slag which was then saturated with CaO. The reaction between slag and substrate resulted in the formation of solid Ca3SiO5, which slowed down the further penetration of slag into the refractory
Printing surface charge as a new paradigm to program droplet transport
Directed, long-range and self-propelled transport of droplets on solid
surfaces, especially on water repellent surfaces, is crucial for many
applications from water harvesting to bio-analytical devices. One appealing
strategy to achieve the preferential transport is to passively control the
surface wetting gradients, topological or chemical, to break the asymmetric
contact line and overcome the resistance force. Despite extensive progress, the
directional droplet transport is limited to small transport velocity and short
transport distance due to the fundamental trade-off: rapid transport of droplet
demands a large wetting gradient, whereas long-range transport necessitates a
relatively small wetting gradient. Here, we report a radically new strategy
that resolves the bottleneck through the creation of an unexplored gradient in
surface charge density (SCD). By leveraging on a facile droplet printing on
superamphiphobic surfaces as well as the fundamental understanding of the
mechanisms underpinning the creation of the preferential SCD, we demonstrate
the self-propulsion of droplets with a record-high velocity over an ultra-long
distance without the need for additional energy input. Such a Leidenfrost-like
droplet transport, manifested at ambient condition, is also genetic, which can
occur on a variety of substrates such as flexible and vertically placed
surfaces. Moreover, distinct from conventional physical and chemical gradients,
the new dimension of gradient in SCD can be programmed in a rewritable fashion.
We envision that our work enriches and extends our capability in the
manipulation of droplet transport and would find numerous potential
applications otherwise impossible.Comment: 11 pages, 4 figure
Scalable Algorithms for Laplacian Pseudo-inverse Computation
The pseudo-inverse of a graph Laplacian matrix, denoted as , finds
extensive application in various graph analysis tasks. Notable examples include
the calculation of electrical closeness centrality, determination of Kemeny's
constant, and evaluation of resistance distance. However, existing algorithms
for computing are often computationally expensive when dealing with
large graphs. To overcome this challenge, we propose novel solutions for
approximating by establishing a connection with the inverse of a
Laplacian submatrix . This submatrix is obtained by removing the -th
row and column from the original Laplacian matrix . The key advantage of
this connection is that exhibits various interesting combinatorial
interpretations. We present two innovative interpretations of based
on spanning trees and loop-erased random walks, which allow us to develop
efficient sampling algorithms. Building upon these new theoretical insights, we
propose two novel algorithms for efficiently approximating both electrical
closeness centrality and Kemeny's constant. We extensively evaluate the
performance of our algorithms on five real-life datasets. The results
demonstrate that our novel approaches significantly outperform the
state-of-the-art methods by several orders of magnitude in terms of both
running time and estimation errors for these two graph analysis tasks. To
further illustrate the effectiveness of electrical closeness centrality and
Kemeny's constant, we present two case studies that showcase the practical
applications of these metrics
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