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Abstract: Water shortages and quality deterioration are serious dilemmas for lake managers as both problems sharply decrease the ecosystem services and functions provided by a lake. In this paper, using WASP as a tool, we have established and calibrated a water quality simulation model for Baiyangdian Lake and then analyzed water quality variations in scenarios with different pollution load reductions and different environmental flow releases into the lake and discovered the sustainable schemes for environmental flow management. From the results, in the scenarios of 30%, 50%, and 90% pollutant load reduction, the sustainable environmental flows are 3.52, 3.13, and 2.12 m3/s, and the corresponding lake levels could attain 7.45 m, 7.35 m, and 7.05 m from the initial 6.0 m. The obtained results indicated that water release could improve the lake volume and quality simultaneously. [Copyright &y& Elsevier]

Abstract: We propose a new multiscale simulation method which seamlessly combines the conventional molecular dynamics (MD) with the continuum mechanics formulated under the material point method (MPM). In MPM, modified interpolation shape functions are adopted to reduce artificial forces on the hierarchical background grids. The multiscale method is validated using the examples of step-like wave and wave packet propagations within a bar. The method is applicable to several kinds of potentials including the Lennard–Jones, EAM and a bonding-angle related potential for silicon. Examples of high energy Cu–Cu and Si–Si cluster impacts are presented. The evolution of displaced atoms is found to depend on the underlying lattice structures. For the case of Cu–Cu cluster impacts, stacking faults play an important role. The displaced atoms, visualized in the method of “local crystalline order”, propagate in an anisotropic manner. This implies the anisotropy in energy transformation process through multi-interactions among cluster and surface atoms. [Copyright &y& Elsevier]

Abstract: This paper presents a numerical study of a gas-particle flow in three inclined rectangular jets in crossflow. The predicted gas phase velocities and particle phase velocities are validated against previously reported experimental data. Two turbulence models, the standard k–ɛ model and Shear Stress Transfer (SST) model, are used to model the gas phase turbulence. This work shows that both models provide acceptable predictions of the gas flow and mixing generated by the three jets. Neither model could accurately reproduce the jet core and the flow near bottom wall. The particle phase in this flow comprises a large number of small particles. Thus particles follow the gas phase flow closely and any errors in the turbulence model and gas flow predictions are passed on to the particle phase simulation. This paper also includes a literature review on rectangular jets in crossflow and gas-particle laden jets in crossflow. [Copyright &y& Elsevier]

Abstract: Effective nasal drug delivery is highly dependent on the delivery of drug from the nasal spray device. Atomisation of liquid spray occurs through the internal atomizer that can produce many forms of spray patterns and two of these, hollow-cone and full-cone sprays, are evaluated in this study to determine which spray pattern produced greater deposition in the middle regions of the nasal cavity. Past studies of spray particle deposition have ignored the device within the nasal cavity. Using computational fluid dynamics (CFD), two computational models of human nasal cavity model were reconstructed from CT-scans, where the difference between the two models was the presence of the nasal spray device accounting for the airway blockage at one of the nostrils. Experimental measurements from Particle Droplet Image Analyser (PDIA) were taken in order to gain confidence in determining the initial particle conditions for the computational models. An airflow field is induced through a negative pressure flow condition applied at the pharynx instead of constant flow rates at the left and the right nasal cavities. Subsequent airflow patterns and its effects on particle deposition, with and without a spray device, are compared. Contours and streamlines of the flow field revealed that the presence of a spray device in the nasal vestibule produced higher levels of disturbed flow, which helped the dispersion of the sprayed particles. Particle deposition was found to be high in the anterior regions of the nasal cavity caused by its inertia. Evaluation of the two spray types found that hollow spray cones produced more deposition in the middle regions of the nasal cavity. This paper also demonstrates the CFD methodology used, which can help in better understanding the design of future atomizers for nasal spray use. [ABSTRACT FROM AUTHOR]

Abstract: The kinetics and thermodynamics of normal grain growth can be linked by two open questions. Is it physically practicable to incorporate the grain boundary (GB) energy decrease with GB segregation into the parabolic kinetics of grain growth? Subsequently, how can a model for grain growth that considers the mixed effect of kinetics and thermodynamics be derived? Departing from Borisov’s equation, a qualitative description is provided to validate the incorporation of GB energy into the grain growth kinetics. Then, a thermokinetic model considering the mixed effect of solute drag and reduced GB energy is developed. Subjected to specific limitations, the thermokinetic model reduces to a purely kinetic model, a purely thermodynamic model and a model considering only grain-size-dependent solute drag. By application of the model to experimental results obtained from nanocrystalline Ni–P and oxygen-doped nickel, it has been shown that the effect of solute drag could retard but not stop the grain growth, and that the main cause of a stabilized nanocrystalline structure is not the solute drag but the reduction in GB energy. [Copyright &y& Elsevier]