Symmetric duality for a class of nondifferentiable multi-objective fractional variational problems

AbstractWe introduce a symmetric dual pair for a class of nondifferentiable multi-objective fractional variational problems. Weak, strong, converse and self duality relations are established under certain invexity assumptions. The paper includes extensions of previous symmetric duality results for multi-objective fractional variational problems obtained by Kim, Lee and Schaible [D.S. Kim, W.J. Lee, S. Schaible, Symmetric duality for invex multiobjective fractional variational problems, J. Math. Anal. Appl. 289 (2004) 505–521] and symmetric duality results for the static case obtained by Yang, Wang and Deng [X.M. Yang, S.Y. Wang, X.T. Deng, Symmetric duality for a class of multiobjective fractional programming problems, J. Math. Anal. Appl. 274 (2002) 279–295] to the dynamic case

MEASUREMENT OF TURBULENCE IN TERRAIN-DISRUPTED AIRFLOW AT THE HONG KONG INTERNATIONAL AIRPORT USING A DOPPLER LIDAR

The Doppler LIDAR of the Hong Kong Observatory was used to measure eddy dissipation rate (EDR) directly for the first time at the Hong Kong International Airport in an experiment in 2004. EDR is a measure of turbulence intensity adopted by the International Civil Aviation Organization. The laser beam of the LIDAR stared in a direction parallel to the runways and radial velocity data were obtained at a range resolution of 60 m. The velocity structure function was computed based on two different estimates of the velocity fluctuation (viz. temporal and spatial methods) and EDR was then calculated by fitting the structure function with the von Kármán model. The two estimates of velocity fluctuation were found to give comparable EDR values. The LIDAR-derived EDR also turned out to have good correlation with EDR obtained from runway anemometers and a boundary-layer wind profiler. In a case of terrain-disrupted airflow during the experiment, the LIDAR-derived EDR showed that turbulence was present near the centre of a micro-scale vortex to the west of the airport

MEASUREMENT OF TURBULENCE IN TERRAIN-DISRUPTED AIRFLOW AT THE HONG KONG INTERNATIONAL AIRPORT USING A DOPPLER LIDAR

The Doppler LIDAR of the Hong Kong Observatory was used to measure eddy dissipation rate (EDR) directly for the first time at the Hong Kong International Airport in an experiment in 2004. EDR is a measure of turbulence intensity adopted by the International Civil Aviation Organization. The laser beam of the LIDAR stared in a direction parallel to the runways and radial velocity data were obtained at a range resolution of 60 m. The velocity structure function was computed based on two different estimates of the velocity fluctuation (viz. temporal and spatial methods) and EDR was then calculated by fitting the structure function with the von Kármán model. The two estimates of velocity fluctuation were found to give comparable EDR values. The LIDAR-derived EDR also turned out to have good correlation with EDR obtained from runway anemometers and a boundary-layer wind profiler. In a case of terrain-disrupted airflow during the experiment, the LIDAR-derived EDR showed that turbulence was present near the centre of a micro-scale vortex to the west of the airport

Impact of relative humidity and length-scale on the performance of a large PEM fuel cell.

Polymer Exchange Membrane Fuel Cell (PEMFC) is emerging as a promising future power source. Research has been focused on small PEMFCs, while its scalability and the performance of large cells remains elusive. This paper presents a numerical investigation into the practicality of expanding a small PEMFC into a large one, and a parametric study on the impact of relative humidity (RH) on the operational performance of the large cell. Numerical predictions are firstly validated against our in-house experimental measurements, where the predicted polarization (V-I) curve is in good agreement with the measurements. Numerical results confirm that water accumulation/flooding exhibits different characteristics at different regions - namely the activation, ohmic loss and concentration loss regions - and poses significant impacts on the current density production. Numerical results also show that the small cell is more susceptible to water flooding in comparison to the large cell under similar operational conditions. Suffering from excessive liquid water, the performance of the small cell is not as good as the large one in the concentration loss region, where a significant increase of current density production is observed. A parametric study on the effect of the humidified reactants on cell performance has been also performed. The increase of RH generally shows an increasing effect on the performance of the cell, while the limitation is found at high RHs (60% and 80%) and low voltage (0.3V), due to the hydration of the membrane and the blockage of reactant delivery

Monitoring of the vertical movements of rail sleepers with the passage of trains

Due to an ever increasing demand for more frequent and higher volume of train service, the physical conditions of tracks in modem railways are deteriorating more quickly when compared to tracks built decades ago. There are incidences in both the UK and Hong Kong indicating there are needs for a more stringent checks on the rail conditions using suitable and effective non-invasive and nondestructive condition monitoring system

Removal of steroid estrogens in carbonaceous and nitrifying activated sludge processes

This is the post-print version of the final paper published in Chemosphere. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.A carbonaceous (heterotrophic) activated sludge process (ASP), nitrifying ASP and a nitrifying/denitrifying ASP have been studied to examine the role of process type in steroid estrogen removal. Biodegradation efficiencies for total steroid estrogens (ΣEST) of 80 and 91% were recorded for the nitrifying/denitrifying ASP and nitrifying ASP respectively. Total estrogen biodegradation (ΣEST) was only 51% at the carbonaceous ASP, however, the extent of biodegradation in the absence of nitrification clearly indicates the important role of heterotrophs in steroid estrogen removal. The low removal efficiency did not correlate with biomass activity for which the ASPcarbonaceous recorded 80 μg kg−1 biomass d−1 compared to 61 and 15 μg kg−1 biomass d−1 at the ASPnitrifying and ASPnitrifying/denitrifying respectively. This finding was explained by a moderate correlation (r2 = 0.55) between total estrogen loading (ΣEST mg m−3 d−1) and biomass activity (μg ΣEST degraded kg−1 d−1) and has established the impact of loading on steroid estrogen removal at full-scale. At higher solids retention time (SRT), steroid estrogen biodegradation of >80% was observed, as has previously been reported. It is postulated that hydraulic retention time (HRT) is as important as SRT as this governs both reaction time and loading. This observation is based on the high specific estrogen activity determined at the ASPcarbonaceous plant, the significance of estrogen loading and the positive linear correlation between SRT and HRT.Public Utilities Board of Singapore, Anglian Water Ltd., Severn Trent Water Ltd., Thames Water Utilities Ltd., United Utilities Plc., and Yorkshire Water Services Ltd

Identifying the Technology Position on Patent Acquisition of Cardiovascular Stent by Complementarity and Supplementary Knowledge

[[abstract]]The most common way for an organization to expand its innovation capability is to acquire technological patent. Consequently, it is an important issue for firms to identify and estimate the target patent. Before acquiring, firms also have to make sure whether the target patents is matching the strategic purpose, and whether the target patent is suitable for the adopting after acquiring. And the result of patent citation analysis can be referred for estimating target patent as the result reveals the technology relationship between firms, the market value of technologies and the technology development strategy. Moreover, technology network analysis can visualize the overall social structure of actors in the technology network and illuminate their relationships and roles. However, few scholars have examined the relative positions of firms in technology networks from the viewpoint of individual social networks. This research uses the idea of the "ego-network", defining the firm's core technology patent portfolio as "ego" while patents which directly cite core patents are defined as the "neighborhood. The purpose of this research is to understand how the firm, through patent transfers, alters its technology position and performs inductive analysis as a reference for future changes in its patent portfolio strategies. The results of this research demonstrate that irrespective of patent transfer strategy, the relative position of firms in the technology network is displaced by patent transfers. By dividing the trajectory of displacement into quadrants the data set may be named as pioneers, leaders, followers, and laggards. And the result shows firms may exit markets, reduce internal subdivisions, carry out cost control, or sell off patents, moving their position to the left or downward and making them followers or laggards. By the same token, when firms enter a new technology area or market, increase their technological capabilities, or acquire technology patents, their position shits to the right or downward, and they become leaders or pioneers.[[notice]]補正完