Hong Kong University of Science and Technology

About: Hong Kong University of Science and Technology is a education organization based out in Hong Kong, Hong Kong, China. It is known for research contribution in the topics: Computer science & Catalysis. The organization has 20126 authors who have published 52428 publications receiving 1965915 citations. The organization is also known as: HKUST & The Hong Kong University of Science and Technology.

Enhanced electrical conductivity of nanocomposites containing hybrid fillers of carbon nanotubes and carbon black.

Abstract: Nanocomposites reinforced with hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) are developed, aiming at enhancing the electrical conductivity of composites with balanced mechanical properties while lowering the cost of the final product. Epoxy-based nanocomposites were prepared with varying combinations of CNTs and CB as conducting fillers, and their electrical and mechanical properties were evaluated. It was shown that the addition of CNTs in CB composites enhanced the electrical conductivity of composites: a low percolation threshold was achieved with 0.2 wt % CNTs and 0.2 wt % CB particles. The CB particles also enhanced the ductility and fracture toughness of nanocomposites, confirming the synergistic effect of CB as a multifunctional filler. The novelty of this work lies in the synergy arising from the combination of two conducting fillers with unique geometric shapes and aspect ratios as well as different dispersion characteristics, which have not been specifically considered previously.

A variational approach to moving contact line hydrodynamics

Abstract: In immiscible two-phase flows, the contact line denotes the intersection of the fluid–fluid interface with the solid wall. When one fluid displaces the other, the contact line moves along the wall. A classical problem in continuum hydrodynamics is the incompatibility between the moving contact line and the no-slip boundary condition, as the latter leads to a non-integrable singularity. The recently discovered generalized Navier boundary condition (GNBC) offers an alternative to the no-slip boundary condition which can resolve the moving contact line conundrum. We present a variational derivation of the GNBC through the principle of minimum energy dissipation (entropy production), as formulated by Onsager for small perturbations away from equilibrium. Through numerical implementation of a continuum hydrodynamic model, it is demonstrated that the GNBC can quantitatively reproduce the moving contact line slip velocity profiles obtained from molecular dynamics simulations. In particular, the transition from complete slip at the moving contact line to near-zero slip far away is shown to be governed by a power-law partial-slip regime, extending to mesoscopic length scales. The sharp (fluid–fluid) interface limit of the hydrodynamic model, together with some general implications of slip versus no slip, are discussed.

Storage space allocation in container terminals

Abstract: Container terminals are essential intermodal interfaces in the global transportation network. Efficient container handling at terminals is important in reducing transportation costs and keeping shipping schedules. In this paper, we study the storage space allocation problem in the storage yards of terminals. This problem is related to all the resources in terminal operations, including quay cranes, yard cranes, storage space, and internal trucks. We solve the problem using a rolling-horizon approach. For each planning horizon, the problem is decomposed into two levels and each level is formulated as a mathematical programming model. At the first level, the total number of containers to be placed in each storage block in each time period of the planning horizon is set to balance two types of workloads among blocks. The second level determines the number of containers associated with each vessel that constitutes the total number of containers in each block in each period, in order to minimize the total distance to transport the containers between their storage blocks and the vessel berthing locations. Numerical runs show that with short computation time the method significantly reduces the workload imbalance in the yard, avoiding possible bottlenecks in terminal operations.

Effects of Substitution with Donor-Acceptor Groups on the Properties of Tetraphenylethene Trimer: Aggregation-Induced Emission, Solvatochromism, and Mechanochromism

Abstract: Luminescent materials with aggregation-induced emission (AIE) property have attracted considerable interests for their promising applications in light-emitting and display devices and fluorescent probes for chemo- and biosensors. Tetraphenylethene (TPE) derivatives are the most attractive species for their notable AIE performance, facile synthesis, and flexible structure modification. To study the effects of donor and acceptor substitutions and extend the applications of TPE-based materials, three TPE kindred, TTPE, BTPEFN, and BATPEFN, are employed. TTPE film displays efficient green fluorescence (λem = 494 nm, ΦF = 100%), evident AIE characteristic (αAIE = 154), and reversible mechanochromism by grinding-fuming: from blue (λem = 472 nm) to green emission (λem = 505 nm). Replacing two phenyls by two cyano (A) groups on the central TPE moiety derives BTPEFN, whose film shows efficient orange fluorescence (λem = 575 nm, ΦF = 100%) and evident AIE (αAIE = 13). The mechanochromic behavior of BTPEFN (from yel...