308 research outputs found
Modelling water from clouds to coast
No full textThe development of new models for predicting coastal flooding will help researchers minimize damage and risks. The Natural Environment Research Council (NERC) launched a research program titled Flood Risk from Extreme Events (FREE) in 2006. The NERC has funded the Ensemble Prediction of Inundation Risk and Uncertainty arising from Scour (EPIRUS) project within the FREE program to bring together a team of hydrometeorologists, oceanographers, and coastal engineers. Qingping Zou, principal investigator for the EPIRUS project and Dominic Reeve, professor of Coastal Dynamics at the University of Plymouth, are collaborating with a team from the University of Bristol led by Professor Ian Cluckie and Proudman Oceanographic Laboratory and the Halcrow Group and the New Forest District Council. Qingping and Dominic hope to develop a new way of predicting coastal flooding system. The ensemble system will facilitate assessment of the uncertainty in forecasting overtopping and scour including coastal flooding.</p
Modelling water from clouds to coast
No full textThe development of new models for predicting coastal flooding will help researchers minimize damage and risks. The Natural Environment Research Council (NERC) launched a research program titled Flood Risk from Extreme Events (FREE) in 2006. The NERC has funded the Ensemble Prediction of Inundation Risk and Uncertainty arising from Scour (EPIRUS) project within the FREE program to bring together a team of hydrometeorologists, oceanographers, and coastal engineers. Qingping Zou, principal investigator for the EPIRUS project and Dominic Reeve, professor of Coastal Dynamics at the University of Plymouth, are collaborating with a team from the University of Bristol led by Professor Ian Cluckie and Proudman Oceanographic Laboratory and the Halcrow Group and the New Forest District Council. Qingping and Dominic hope to develop a new way of predicting coastal flooding system. The ensemble system will facilitate assessment of the uncertainty in forecasting overtopping and scour including coastal flooding.</p
Resilience of Critical Infrastructure Systems to Floods:A Coupled Probabilistic Network Flow and LISFLOOD-FP Model
No full textIn this paper, a network-flow model was constructed to simulate the performance of interdependent critical infrastructure systems during flood hazards, when there is shortage of commodities such as electrical power and water. The model enabled us to control the distribution of commodities among different consumers whose demand cannot be fully met. Incorporating time-variance in the model allowed for evaluating the time evolution of the functional level of the infrastructure systems and quantifying their resilience. As a demonstration of the model’s capability, the network model was coupled with a raster-based hydraulic flooding model in the way of Monte Carlo simulations. It was then used to investigate the cascading effects of flood-related failures of individual infrastructure assets on the performance of the critical infrastructure systems of a coastal community under different flooding scenarios and future climate impacts. The coupled modelling framework is essential for correctly assessing the interdependences and cascading effects in the infrastructure systems in the case of flood hazards. While in the considered example, the extent of inundation becomes less severe with a changing climate, the risk to infrastructure does not recede because of the cascading effects. This behaviour could not be captured by the flood model alone
Qingping Straight Sword: The Last Remaining Chinese Sword System?
No full textThe following examination of classical Chinese straight sword (jian) details the very rare Qingping straight sword system. The study meshes Chinese- and English-sourced research with a revealing interview (conducted by America’s senior Qingping disciples, Reza Momenan and Hon Lee) with Lu Junhai—the grandmaster of this unique sword system. The author presents Qingping system as perhaps the only known, complete Chinese sword system surviving from China’s pre-Rebulican era (1911-1949).</p
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Retraction: Crystal structure of a Baeyer–Villiger flavin‐containing monooxygenase from Staphylococcus aureus MRSA strain MU50, William C. Hwang, Qingping Xu, Bainan Wu, Adam Godzik
Full text linkThe above article from Proteins: Structure, Function, and Bioinformatics, published online on 5 August 2014 in Wiley Online Library (http://onlinelibrary.wiley.com/doi/10.1002/prot.24661/full), has been retracted by agreement between William C. Hwang, Qingping Xu, Bainan Wu, Adam Godzik, the Editor‐in‐Chief, Bertrand E. Garcia‐Moreno, and Wiley Periodicals, Inc. The retraction has been agreed because submission was made without agreement from co‐author Adam Godzik
Generation, transformation, and scattering of long waves induced by a short-wave group over finite topography
No full textSecond-order analytical solutions are constructed for various long waves generated by a gravity wave train propagating over finite variable depth h(x) using a multiphase Wentzel-Kramers-Brillouin (WKB) method. It is found that, along with the well-known long wave, locked to the envelope of the wave train and traveling at the group velocity Cg, a forced long wave and free long waves are induced by the depth variation in this region. The forced long wave depends on the depth derivatives hx and hxx and travels at Cg, whereas the free long waves depend on h, hx, and hxx and travel in the opposite directions at √gh. They interfere with each other and generate free long waves radiating away from this region. The author found that this topographyinduced forced long wave is in quadrature with the short-wave group and that a secondary long-wave orbital velocity is generated by variable water depth, which is in quadrature with its horizontal bottom counterpart. Both these processes play an important role in the energy transfer between the short-wave groups and long waves. These behaviors were not revealed by previous studies on long waves induced by a wave group over finite topography, which calculated the total amplitude of long-wave components numerically without consideration of the phase of the long waves. The analytical solutions here also indicate that the discontinuity of hx and hxx at the topography junctions has a significant effect on the scattered long waves. The controlling factors for the amplitudes of these long waves are identified and the underlying physical processes systematically investigated in this presentation.</p
The Characteristics, Enrichment, and Migration Mechanism of Cadmium in Phosphate Rock and Phosphogypsum of the Qingping Phosphate Deposit, Southwest China
No full textSedimentary phosphate rocks are characteristically rich in organic matter, and contain sulfides and a high concentration of trace elements, including cadmium (Cd), which is harmful to the human body. The mining of phosphate rock and phosphogypsum at Qingping has expanded the release of Cd into groundwater and farmland soil. To prevent and control Cd pollution it is critical to reveal the carrier mineral phase(s) and migration mechanism of Cd and other elements in phosphate rock and phosphogypsum. The elemental and mineral composition of bulk samples were analysed by XRF, ICP-MS, and XRD, respectively. The results showed that from phosphate rock to phosphogypsum, the main constituent elements changed from CaO (49.43%) and P2O5 (36.63%) to CaO (33.65%) and SO3 (>34%), and the main mineral changed from fluorapatite to gypsum. Among all the elements, the element transfer factor (ETF) of P2O5, F, Co, U, Cd, and other elements was low; the ETF (Cd) was only 10.85%, and only a small amount of Cd entered the acidic phosphogypsum during the production process. Raman spectroscopy analysis revealed two types of apatite: the brown–black apatite with organic matter (type 1) and the yellow–light brown apatite without organic matter (type 2). LA-ICP-MS analysis showed that the Cd element content in type 2 was lower, while the organic matter and Cd element content in type 1 were higher, suggesting that Cd may be controlled by organic matter, and the relationship with apatite is not apparent. Electron probe analysis and XRD semiquantitative results show that the content of Cd in pyrite is higher (511 ppm), which is significantly higher than that of bulk rock. In addition, pyrite is rich in Co, As, Ni, Zn, and other elements. The content of Cd in phosphate ore shows a good correlation with that of pyrite. Cd in Qingping phosphate rock is mainly controlled by organic matter and pyrite, and only a small amount of Cd is transferred to phosphogypsum. Reducing the environment leads to the enrichment of Cd in phosphate rock
An analytical model of wave bottom boundary layers incorporating turbulent relaxation and diffusion effects
No full textTo calculate the effects of turbulent relaxation on oscillatory turbulent boundary layers, a viscoelastic term is added to an eddy viscosity model. The viscoelastic term parameterizes the lag of turbulent properties in response to imposed oscillatory shear and is proportional to the ratio between the timescales of eddy dissipation and of the oscillating flow. It is found that the turbulent relaxation plays an important role in the phase variations of velocity and shear stress with elevation, and that it decreases the friction factor and the phase lead of bed shear stress over free stream velocity. To assess the effects of turbulent diffusion in this problem, the viscoelastic model is extended by further introducing a turbulent diffusion term in the model. The comparisons between these two models indicate that turbulent diffusion significantly reduces the magnitudes of shear stress and velocity perturbation in the outer region of the boundary layer. It is also found that the effects of turbulent relaxation and diffusion increase with increasing relative roughness. As a result, the analytical solutions demonstrate an overall improvement over the eddy viscosity model in predicting the observed temporal evolution of velocity and shear stress profiles; this improvement is more distinct for rough beds than smooth beds.</p
Strain and temperature sensors using multimode optical fiber Bragg gratings and correlation signal processing
No full textMultimode fiber optic Bragg grating sensors for
strain and temperature measurements using correlation signal processing methods have been developed. Two multimode Bragg grating sensors were fabricated in 62/125 m graded-index silica
multimode fiber; the first sensor was produced by the holographic method and the second sensor by the phase mask technique. The sensors have signal reflectivity of approximately 35% at peak
wavelengths of 835 nm and 859 nm, respectively.
Strain testing of both sensors has been done from 0 to 1000 με and the temperature testing from 40 to 80°C. Strain and temperature sensitivity values are 0.55 pm/με and 6 pm/°C, respectively.
The sensors are being applied in a power-by-light hydraulic valve monitoring system
Wind and current effects on extreme wave formation and breaking
Full text linkWind and current effects on the evolution of a two-dimensional dispersive focusing wave group are investigated using a two-phase flow model. A Navier-Stokes solver is combined with the Smagorinsky subgrid-scale stress model and volume of fluid (VOF) air-water interface capturing scheme.Model predictions compare well with the experimental data with and without wind. It was found that the following and opposing winds shift the focus point downstream and upstream, respectively. The shift of focus point is mainly due to the action of wind-driven current instead of direct wind forcing. Under strong following/opposing wind forcing, there appears a slight increase/ decrease of the extreme wave height at the focus point and an asymmetric/symmetric behavior in thewave focusing and defocusing processes. Under a weak following wind, however, the extreme wave height decreases with increasing wind speed because of the dominant effect of the wind-driven current over direct wind forcing. The vertical shear of the wind-driven current plays an important role in determining the location of and the extreme wave height at the focus point under wind actions. Furthermore, it was found that the thin surface layer current is a better representation of the wind-driven current for its role in wind influences on waves than the depth-uniform current used by previous studies.Airflow structure above a breakingwave group and its link to the energy flux from wind to wave as well as wind influence on breaking are also examined. The flow structure in the presence of a following wind is similar to that over a backward-facing step, while that in the presence of an opposing wind is similar to that over an airfoil at high angles of attack. Both primary and secondary vortices are observed over the breaking wave with and without wind of either direction. Airflow separates over the steep crest and causes a pressure drop in the lee of the crest. The resulting form dragmay directly affect the extreme wave height. The wave breaking location and intensity are modified by the following and opposing wind in a different fashion.</p
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