Hong Kong Polytechnic University

About: Hong Kong Polytechnic University is a education organization based out in Hong Kong, China. It is known for research contribution in the topics: Computer science & Tourism. The organization has 29633 authors who have published 72136 publications receiving 1956312 citations. The organization is also known as: HKPU & PolyU.

Photocatalytic degradation of 2-mercaptobenzothiazole in aqueous La3+–TiO2 suspension for odor control

Abstract: The La3+–TiO2 photocatalysts were prepared by doping lanthanum ion into TiO2 structure in a sol–gel process. The catalyst samples were then characterized by XRD and XPS analyses. The analytical results demonstrated that the lanthanum doping could inhibit the phase transformation of TiO2 and enhance the thermal stability of TiO2 structure. In addition, it was found that the lanthanum doping could reduce the crystallite size and increase the Ti3+ content on the surface of the catalysts with the increase of lanthanum doping. With a purpose of odor control, 2-mercaptobenzothiazole (MBT) was used in this study as a model chemical and both the adsorption isotherm and photocatalytic activity of the La3+–TiO2 catalysts were evaluated based on the MBT photodegradation in aqueous solution. The experimental results showed that both the adsorption capacity and adsorption equilibrium constants of the La3+–TiO2 catalysts increased with an increase of lanthanum doping. The kinetics of the MBT photodegradation using different La3+–TiO2 catalysts was also studied. The experiments demonstrated that an optimum doping of lanthanum ion at 1.2% achieved the highest MBT photodegradation rate. It was concluded that the enhancement of MBT photodegradation using the La3+–TiO2 catalysts mainly involved in both the improvement of the organic substrate adsorption in catalysts suspension and the enhancement of the separation of electron-hole pairs owing to the presence of Ti3+.

Revisiting Hughes’ dynamic continuum model for pedestrian flow and the development of an efficient solution algorithm

Abstract: In this paper, we revisit Hughes’ dynamic continuum model for pedestrian flow in a two-dimensional walking facility that is represented as a continuum within which pedestrians can freely move in any direction [Hughes, R.L., 2002. A continuum theory for the flow of pedestrians. Transportation Research Part B, 36 (6), 507–535]. We first reformulate Hughes’ model, and then show that the pedestrian route choice strategy in Hughes’ model satisfies the reactive dynamic user equilibrium principle in which a pedestrian chooses a route to minimize the instantaneous travel cost to the destination. In this model, the pedestrian demand is time varying. The pedestrian density, flux, and walking speed are governed by the conservation equation. A generalized cost function is considered. The reformulated problem is solved by the efficient weighted essentially non-oscillatory scheme for the conservation equation and the fast sweeping method for the Eikonal equation. A numerical example is used to demonstrate the effectiveness of the proposed solution procedure.

The genetic and environmental factors for keratoconus.

Abstract: Keratoconus (KC) is the most common cornea ectatic disorder. It is characterized by a cone-shaped thin cornea leading to myopia, irregular astigmatism, and vision impairment. It affects all ethnic groups and both genders. Both environmental and genetic factors may contribute to its pathogenesis. This review is to summarize the current research development in KC epidemiology and genetic etiology. Environmental factors include but are not limited to eye rubbing, atopy, sun exposure, and geography. Genetic discoveries have been reviewed with evidence from family-based linkage analysis and fine mapping in linkage region, genome-wide association studies, and candidate genes analyses. A number of genes have been discovered at a relatively rapid pace. The detailed molecular mechanism underlying KC pathogenesis will significantly advance our understanding of KC and promote the development of potential therapies.