Improvement of simulating BMPs and LID practices in L-THIA-LID model

Best management practices (BMPs) and low impact development (LID) practices are popular approaches used to reduce the negative impacts of urbanization on hydrology and water quality. To assist planners and decision-makers in urban development projects, user-friendly tools are needed to assess the effectiveness of BMPs and LID practices on water quantity and quality. To address this need, the Long-Term Hydrologic Impact Assessment-LID (L-THIA-LID) model was enhanced with additional commonly used BMPs and LID practices represented in the model, improved approaches to estimate hydrology and water quality, and representation of practices in series. The tool was used to evaluate the performance of BMPs and LID practices individually and in series in four types of idealized land use units and watersheds (low density residential area, high density residential area, industrial area, and commercial area). Simulation results were comparable with the observed impacts of these practices in other published studies. Then, the model was enhanced further by creating L-THIA-LID 2.1 for modelling BMPs/LID practices at watershed scales and adding cost estimates of practices. The sensitivity and uncertainty of the enhanced model were analyzed using SobolOefs global sensitivity analysis method and the bootstrap method, respectively. CN (Curve Number) and Ratio_r (Practice outflow runoff volume/inflow runoff volume) were the most sensitive variables before and after BMPs/LID practices were implemented, respectively. The limited observed data in the same study area and results from other urban watersheds in scientific literature were either well within or close to the uncertainty ranges found in this study, indicating the model has good precision. Sixteen implementation scenarios of BMPs and LID practices were evaluated with the model at the watershed scale. The implementation of grass strips in 25% of the watershed where this practice could be applied was the most cost-efficient scenario. The scenario with very high levels of BMP and LID practice adoption provided the greatest reduction in runoff volume and pollutant loads among all scenarios. However, this scenario was not as cost-efficient as most other scenarios. The L-THIA-LID 2.1 model is a valid tool that can be applied to various locations to help identify cost effective BMP/LID practice plans at watershed scales. Finally, a decision support tool, which linked L-THIA-LID 2.1 with the A Multi-ALgorithm Genetically Adaptive Multiobjective (AMALGAM) method using the multilevel spatial optimization (MLSOPT) framework, was developed to optimally select and place BMPs/LID practices. The decision support tool was applied to an urban watershed near Indianapolis, Indiana. Optimization results at the hydrologic response unit scale indicated that for sites with different features, the optimal BMP/LID practice solutions to attain the same environmental goals differed. For sites with the same characteristics, the optimal implementation of practices could vary significantly for different environmental goals. For higher expenditures, the implementation levels and types of favored practices tended to increase relative to those for lower expenditures. Watershed scale results showed that for initial expenditures of practices, the environmental benefits increased rapidly as expenditures increased. However, beyond certain expenditure levels, additional spending did not result in noticeable additional environmental impacts. Compared to random placement of practices, the optimization strategy provided 3.9 to 7.7 times the level of runoff/pollutant load reductions for the same expenditures. To obtain the same environmental benefits, costs of random practices placement were 4.2 to 14.5 times the optimized practice placement cost. Results indicate that the decision support tool is capable of supporting decision makers in optimally selecting and placing BMPs and LID practices at watershed scales

Broadband Antireflection Coverglass for CubeSats

A CubeSat is a type of miniaturized and modular satellite designed for space research or technology demonstration. By filling the unused capacity of major launch vehicles, CubeSats significantly lower the cost of entry to space. To reduce the energy loss at the solar panel coverglass on CubeSats, we investigated the potential of the biomimetic moth-eye antireflection (MEAR) techniques which feature a gradient refractive index (GRIN). A novel fabrication process combining nanosphere lithography, reactive ion etching and dry oxidation for patterning glass with moth-eye structures was reported that allows for the production of well-defined nanopillars with tunable sidewall profiles. The thermal annealing treatment of colloidal particles was first introduced for making MEAR structures for which partial deformation of nanospheres was achieved. The broadband and omni-directional anti-reflective performance of fabricated glasses was experimentally demonstrated by using spectrophotometer and ellipsometer. A 2% and 10% decrease of reflectance throughout the measured spectral range was observed at normal incidence and high incident angles respectively

Improvement of simulating BMPs and LID practices in L-THIA-LID model

Best management practices (BMPs) and low impact development (LID) practices are popular approaches used to reduce the negative impacts of urbanization on hydrology and water quality. To assist planners and decision-makers in urban development projects, user-friendly tools are needed to assess the effectiveness of BMPs and LID practices on water quantity and quality. To address this need, the Long-Term Hydrologic Impact Assessment-LID (L-THIA-LID) model was enhanced with additional commonly used BMPs and LID practices represented in the model, improved approaches to estimate hydrology and water quality, and representation of practices in series. The tool was used to evaluate the performance of BMPs and LID practices individually and in series in four types of idealized land use units and watersheds (low density residential area, high density residential area, industrial area, and commercial area). Simulation results were comparable with the observed impacts of these practices in other published studies. Then, the model was enhanced further by creating L-THIA-LID 2.1 for modelling BMPs/LID practices at watershed scales and adding cost estimates of practices. The sensitivity and uncertainty of the enhanced model were analyzed using SobolOefs global sensitivity analysis method and the bootstrap method, respectively. CN (Curve Number) and Ratio_r (Practice outflow runoff volume/inflow runoff volume) were the most sensitive variables before and after BMPs/LID practices were implemented, respectively. The limited observed data in the same study area and results from other urban watersheds in scientific literature were either well within or close to the uncertainty ranges found in this study, indicating the model has good precision. Sixteen implementation scenarios of BMPs and LID practices were evaluated with the model at the watershed scale. The implementation of grass strips in 25% of the watershed where this practice could be applied was the most cost-efficient scenario. The scenario with very high levels of BMP and LID practice adoption provided the greatest reduction in runoff volume and pollutant loads among all scenarios. However, this scenario was not as cost-efficient as most other scenarios. The L-THIA-LID 2.1 model is a valid tool that can be applied to various locations to help identify cost effective BMP/LID practice plans at watershed scales. Finally, a decision support tool, which linked L-THIA-LID 2.1 with the A Multi-ALgorithm Genetically Adaptive Multiobjective (AMALGAM) method using the multilevel spatial optimization (MLSOPT) framework, was developed to optimally select and place BMPs/LID practices. The decision support tool was applied to an urban watershed near Indianapolis, Indiana. Optimization results at the hydrologic response unit scale indicated that for sites with different features, the optimal BMP/LID practice solutions to attain the same environmental goals differed. For sites with the same characteristics, the optimal implementation of practices could vary significantly for different environmental goals. For higher expenditures, the implementation levels and types of favored practices tended to increase relative to those for lower expenditures. Watershed scale results showed that for initial expenditures of practices, the environmental benefits increased rapidly as expenditures increased. However, beyond certain expenditure levels, additional spending did not result in noticeable additional environmental impacts. Compared to random placement of practices, the optimization strategy provided 3.9 to 7.7 times the level of runoff/pollutant load reductions for the same expenditures. To obtain the same environmental benefits, costs of random practices placement were 4.2 to 14.5 times the optimized practice placement cost. Results indicate that the decision support tool is capable of supporting decision makers in optimally selecting and placing BMPs and LID practices at watershed scales

Enhancement of power output by a new stress-applied mode on circular piezoelectric energy harvester

A new stress-applied mode is proposed on piezoelectric circular diaphragm energy harvester. Differing from the usual mode used in previous researches, the mass stick at the center of the diaphragm (PZT-51) is designed into an annular hollow shape. In this case, stress of the mass is applied along the edge of the copper sheet. A screw bonded with the undersurface of the diaphragm transfers force from the vibrator to the diaphragm. This device has a cylindrical shape and its volume is ∼7.9 cm3. With this new stress-applied mode, the piezoelectric energy harvester (with an optimal load of 18 kΩ, a mass of 30 g) could generate a maximum power output of ∼20.8 mW under 9.8 m·s-2 at its resonant frequency of ∼237 Hz. Meanwhile, the greater the hardness ratio between the ceramic and the copper sheet, the greater the advantages of the new structure

Assessment of the Impacts of Land Use/Cover Change and Rainfall Change on Surface Runoff in China

Assessment of the impacts of land use/cover change (LUCC) and rainfall change on surface runoff depth can help provide an understanding of the temporal trend of variation of surface runoff and assist in urban construction planning. This study evaluated the impacts of LUCC and rainfall change on surface runoff depth by adopting the well-known Soil Conservation Service-Curve Number (SCS-CN) method and the widely used Long-Term Hydrologic Impact Assessment (L-THIA) model. National hydrologic soil group map of China was generated based on a conversion from soil texture classification system. The CN values were adjusted based on the land use/cover types and soil properties in China. The L-THIA model was configured by using the adjusted CN values and then applied nationally in China. Results show that nationwide rainfall changes and LUCC from 2005 to 2010 had little impact on the distribution of surface runoff, and the high values of runoff depth were mainly located in the middle and lower reaches of the Yangtze River. Nationally, the average annual runoff depths in 2005, 2010 and 2015 were 78 mm, 83 mm and 90 mm, respectively. For the 2015 land use data, rainfall change caused the variation of surface runoff depth ranging from −203 mm to 476 mm in different regions. LUCC from 2005 to 2015 did not cause obvious change of surface runoff depth, but expansion of developed land led to runoff depth increases ranging from 0 mm to 570 mm and 0 mm to 742 mm from 2005 to 2010 and 2010 to 2015, respectively. Potential solutions to urban land use change and surface runoff control were also analyzed

Comprehensive analysis of important parameters of choline chloride-based deep eutectic solvent pretreatment of lignocellulosic biomass

Choline chloride based deep eutectic solvents have showed great potential in lignocellulosic biomass pretreatment. In this study, for DES pretreatment with different hydrogen bond donners of different raw materials under different reaction conditions, multivariate analysis methods including principal component analysis and partial least squares analysis were used for reveal the pretreatment mechanism by evaluating the inner relationships among 42 key process factors. Furthermore, based on molecular simulation, the detailed relationships between key variables were further analyzed. Meanwhile, four-dimensional color graphs were used to intuitively reveal the synergistic influence of multivariate conditions variables on pretreatment effect to obtain better economic benefits and energy consumption indicators for DES pretreatment. The results showed that HBD hydrophilic ability, HBD polarity, HBD acidity, HBD ability to form hydrogen bonds, molar ratio of HBD to choline chloride and pretreatment severity had great influence on the Choline chloride based deep eutectic solvents pretreatment effect

Probing the Interfacial Charge-Transfer Process of Uniform ALD Semiconductor–Molecule–Metal Models: A SERS Study

Among all coating methods, atomic layer deposition (ALD), which can provide a precise thickness control at the angstrom or the monolayer level, appears to be one of the most promising techniques. To investigate the interfacial charge-transfer mechanism from semiconductor–molecule–metal systems, the order of different layers is very essential because the charge-transfer process can be affected by the interfacial contact order of different materials. Also, for TiO₂/MBA/Ag charge-transfer (CT) investigation, homogeneous assembling of TiO₂ with precisely controllable thickness is of great importance because the energy level of semiconductor is sensitive to its size at the nanoscale. Here, unlike previous 3D composite CT models, our semiconductor–molecule–metal interfacial CT models are fabricated with the ALD and e-beam evaporation techniques, which ensures the accuracy of the CT investigation. The surface-enhanced Raman scattering (SERS) technique is adopted in the investigation of the interfacial charge-transfer process through the changes of CT-sensitive bands. In TiO₂/MBA/Ag, the SERS signal of MBA molecules and the Raman spectra of TiO₂ phonon vibrational mode exhibit evident CT-driven changes. To confirm these phenomena, 4 nm thickness of wide-bandgap HfO₂ and Al₂O₃ are inserted as isolated layers. Also, the possible CT mechanisms and the charge-transfer degree in different systems are discussed. This work not only suggests a role for ALD in fabricating CT models but also promotes the application of SERS in more intensive fields