Corn stover for bioenergy production has been in development because of its environmental benefits and displacement of conventional energy. This study compared, from cradle-to-grave life-cycle assessment (LCA) perspective, energy performance and environmental impacts among corn stover-based bioenergy pathways of production of electricity (CSE), bioethanol (CSB) and bio-natural gas (CSG) in China. The tool used was the eBalance model with a local database. The results indicated that no single conversion pathway simultaneously maximizes energy and environmental performance. The study showed that the CSE pathway exhibited the best energy performance (energy input/output = 39%), whereas the CSB pathway presented the best comprehensive environmental performance. The global warming potential (GWP) mitigation ranged from 0.50 kg CO2-eq to 149.39 kg CO2-eq per metric ton of fresh corn stover of 86% moisture for the three pathways. Assuming that half of the corn stover in China were used for the three bioenergy production pathways, the GWP mitigation would reach 42.38 million ton CO2-eq in 2020. A breakdown of environmental impacts indicated that contributions of sub-processes varied among the three pathways. The study suggested that electricity consumption for the CSB and CSG pathways and nitrogen utilization in cornfield for the CSE pathway should be decreased to reduce GWP in further corn stover-based bioenergy production according to a sensitivity analysis. (C) 2020 Elsevier Ltd. All rights reserved.

Sunscreen products contain UV filters as active ingredients for the protection of the skin against UVR. The US Food and Drug Administration (FDA) issued a new proposed rule in 2019 (84.FR.6204) for sunscreens and identified the need for additional safety data for certain UV filters including their dermal absorption data. Dermal absorption data reveal systemic exposure of UV filters in humans, which can be obtained from clinical maximal usage trials. FDA guidance recommends conducting in vitro skin permeation tests (IVPTs) to help select formulations for maximal usage clinical trials as IVPT results may be indicative of in vivo absorption. This case study reports in vitro methodologies used for the selection of sunscreen products for an FDA-sponsored proof-of-concept maximal usage clinical trial. An IVPT method was developed using human cadaver skin. Commercially available sunscreen products were tested to determine the skin absorption potential of common UV filters using the IVPT. All the studied sunscreen products demonstrated a certain degree of skin absorption of UV filters using IVPT, and a formulation rank order was obtained. These sunscreen products were also characterized for several formulation properties including the globule size in emulsions, which was found to be an indicator for the rank order.

In this work, co-pyrolysis of Miscanthus Sacchariflorus (MS) and three ranks of coal, namely lignite (LC), bituminous coal (BC), and anthracite (AC), was performed at the analytical scale. The co-pyrolysis kinetic and products were analysed and compared theoretically and experimentally. The results revealed the synergistic effects of the coal characterstics and biomass blend ratio (BBR) on the thermal decomposition and the products in gaseous phase. The co-pyrolysis of MS-LC and MS-BC samples was characterised by three distinct stages, which were sequentially dominated by moisture removal, decomposition of MS and decomposition of coal. The activation energies of the co-pyrolysis process were different from the activation energies of the pyrolysis of individual MS and coal samples. The kinetics analysis showed that increasing the BBR increased the activation energies of the MS-coal blends up to 25% at the temperatures below 350 degrees C. However, at the higher temperature range, it decreased the activation energies of MS-LC and MS-BC blends but increased those of MS-AC blends. Both of the coal rank and BBR had noticeable impacts on the thermal behaviour during co-pyrolysis. The optimum positive synergistic effects were obtained on MS-LC blend with a BBR of 1:1. The FTIR analysis results showed the evolution profiles of CH4, CO, CO2, water, formic acid, phenol and xylene. All the products analysed showed L-peaks (250-400 degrees C) corresponding to MS decomposition. Increasing the BBR promoted the release of all the analysed products from MS-LC and MS-BC, indicating the synergistic effect of the co-pyrolysis.

The discrete fracture model (DFM) has been widely used in the simulation of fluid flow in fractured porous media. Traditional DFM uses the so-called hybrid-dimensional approach to treat fractures explicitly as low-dimensional entries (e.g. line entries in 2D media and face entries in 3D media) on the interfaces of matrix cells and then couple the matrix and fracture flow systems together based on the principle of superposition with the fracture thickness used as the dimensional homogeneity factor. Because of this methodology, DFM is considered to be limited on conforming meshes and thus may raise difficulties in generating high quality unstructured meshes due to the complexity of fracture's geometrical morphology. In this paper, we clarify that the DFM actually can be extended to non-conforming meshes without any essential changes. To show it clearly, we provide another perspective for DFM based on hybrid-dimensional representation of permeability tensor to describe fractures as one-dimensional line Dirac delta functions contained in permeability tensor. A finite element DFM scheme for single-phase flow on non-conforming meshes is then derived by applying Galerkin finite element method to it. Analytical analysis and numerical experiments show that our DFM automatically degenerates to the classical finite element DFM when the mesh is conforming with fractures. Moreover, the accuracy and efficiency of the model on non-conforming meshes are demonstrated by testing several benchmark problems. This model is also applicable to curved fracture with variable thickness. (C) 2020 Elsevier Inc. All rights reserved.

This study investigates the wind-wave coupling effects on fatigue damage of tendons that connect multiple bodies of a novel floating platform (TELWIND) supporting a 10 MW wind turbine. An aero-hydro-servo tool is developed for dynamic analysis of a multi-body floating wind turbine (FWT) platform, by incorporating AeroDyn with AQWA through a user-defined dynamic library link (DLL) to conduct simulations of the FWT subjected to wind, wave and current loadings. The comparison against FAST has validated the accuracy of the AQWA-AeroDyn coupling framework in predicting coupled responses of the FWT. A specific site in the northern coast of Scotland is selected and design load cases are examined for the estimation of the fatigue damage of the tendons of the FWT. In the absence of wind-wave coupling, the motion differences between the two bodies of the platform are larger, leading to 43.7% enhancement in the tension fluctuation of tendons in average. Consequently, the fatigue damage of the tendons is significantly overestimated. Also, the investigation on the influence of effective simulation length on the fatigue damage shows that 90% accuracy can be achieved when 20% of the simulation analysis length is decreased.

In this paper we present a study on the mitigation of dynamic responses of a 10 MW monopile offshore wind turbine under coupled wind-wave-earthquake excitations. We have developed and validated the generic seismic coupled analysis and structural control architecture tool to overcome the limitation of numerical tools when examining the wind-wave-earthquake coupling effects. We investigated the dynamic responses of a 10 MW monopile offshore wind turbine under different loading combinations and found that the earthquake loading increases the tower-top displacement and pile-cap moment by 47.6% and 95.1%, respectively, compared to the wind-wave-only condition. It is found that the earthquake-induced vibration in the fore-aft direction is mitigated by the wind and wave loadings due to the energy dissipated by the aerodynamic and hydrodynamic damping. In addition, the tower responses are dominated by the earthquake excitation. In order to alleviate the tower vibration induced by the earthquake, we implemented the structural control capability within the tool using tuned mass dampers. The tuned mass dampers with appropriately selected design parameters achieve a larger mitigation on the tower-top displacement for the earthquake-only condition compared to the coupled-loading scenario. The reason is that the tuned mass damper is only effective in mitigating tower vibration, and it is not capable of reducing the tower elastic deformation which is the major contribution of the tower displacement for the coupled-loading condition. In addition, we have found that a heavier tuned mass damper requires a lower tuned frequency to achieve a larger mitigation. A configuration for the mitigation control of the 10 MW offshore wind turbine is suggested by using a 5% mass ratio of the tuned mass damper. (C) 2020 Elsevier Ltd. All rights reserved.