•We modeled hydrology of the entire European continent with SWAT.•We included river discharge and nitrate loads as well as crop yield in the model.•We provide a protocol for calibration of ...large-scale models with uncertainty analysis.•We modeled blue and green water resources of Europe at subbasin level.•We improved SWAT-CUP to include parallel processing and visualization.
A combination of driving forces are increasing pressure on local, national, and regional water supplies needed for irrigation, energy production, industrial uses, domestic purposes, and the environment. In many parts of Europe groundwater quantity, and in particular quality, have come under sever degradation and water levels have decreased resulting in negative environmental impacts. Rapid improvements in the economy of the eastern European block of countries and uncertainties with regard to freshwater availability create challenges for water managers. At the same time, climate change adds a new level of uncertainty with regard to freshwater supplies. In this research we build and calibrate an integrated hydrological model of Europe using the Soil and Water Assessment Tool (SWAT) program. Different components of water resources are simulated and crop yield and water quality are considered at the Hydrological Response Unit (HRU) level. The water resources are quantified at subbasin level with monthly time intervals. Leaching of nitrate into groundwater is also simulated at a finer spatial level (HRU). The use of large-scale, high-resolution water resources models enables consistent and comprehensive examination of integrated system behavior through physically-based, data-driven simulation. In this article we discuss issues with data availability, calibration of large-scale distributed models, and outline procedures for model calibration and uncertainty analysis. The calibrated model and results provide information support to the European Water Framework Directive and lay the basis for further assessment of the impact of climate change on water availability and quality. The approach and methods developed are general and can be applied to any large region around the world.
Large-scale distributed watershed models are data-intensive, and preparing them consumes most of the research resources. We prepared high-resolution global databases of soil, landuse, actual ...evapotranspiration (AET), and historical and future weather databases that could serve as standard inputs in Soil and Water Assessment Tool (SWAT) models. The data include two global soil maps and their associated databases calculated with a large number of pedotransfer functions, two landuse maps and their correspondence with SWAT's database, historical and future daily temperature and precipitation data from five IPCC models with four scenarios; and finally, global monthly AET data. Weather data are 0.5° global grids text-formatted for direct use in SWAT models. The AET data is formatted for use in SWAT-CUP (SWAT Calibration Uncertainty Procedures) for calibration of SWAT models. The use of these global databases for SWAT models can speed up the model building by 75-80% and are extremely valuable in areas with limited or no physical data. Furthermore, they can facilitate the comparison of model results in different parts of the world.
The local flow topology is studied using the invariants of the velocity gradient tensor in compressible turbulent mixing layer via direct numerical simulation (DNS) data. The topological and ...dissipating behaviours of the flow are analysed in two different regions: in proximity of the turbulent/non-turbulent interface (TNTI), and inside the turbulent region. It is found that the distribution of various flow topologies in regions close to the TNTI differs from inside the turbulent region, and in these regions the most probable topologies are non-focal. In order to better understand the behaviour of different flow topologies, the probability distributions of vorticity norm, dissipation and rate of stretching are analysed in incompressible, compressed and expanded regions. It is found that the structures undergoing compression–expansion in axial–radial directions have the highest contraction rate in locally compressed regions, and in locally expanded regions the structures undergoing expansion–compression in axial–radial directions have the highest stretching rate. The occurrence probability of different flow topologies conditioned by the dilatation level is presented and it is shown that the structures in the locally compressed regions tend to have stable topologies while in locally expanded regions the unstable topologies are prevalent.
In this study, the rate of dislocation accumulation in the tensile strained twinning induced plasticity (TWIP) steel was calculated via the X-ray diffraction (XRD) measurements and compared with ...other fcc metals and alloys. The results indicated that the XRD technique is an alternative method to estimate the dislocation density. Moreover, flow stress analysis of Fe–31Mn–3Al–3Si TWIP steel with the grain size of about 18
μm indicated that, beside a direct effect of the dislocation interactions on the flow stress, another strengthening mechanism is also required to describe the flow behavior. For this reason, the strengthening contribution due to the formation of mechanical twins was considered as a reduction of dislocation mean free path. Interestingly, the estimated flow stress equation consisting of the strengthening effects of both dislocation interactions and dynamic microstructure refinement due to mechanical twinning (i.e., the dynamic Hall–Petch effect) are in good agreement with the experimental data and equation proposed by Ludwigson for low SFE materials.
Compocasting of A356-CNT composite ABBASIPOUR, B.; NIROUMAND, B.; MONIR VAGHEFI, S.M.
Transactions of Nonferrous Metals Society of China,
09/2010, Letnik:
20, Številka:
9
Journal Article
Recenzirano
A356 aluminum alloys reinforced with carbon nano-tubes （CNTs） were produced by stir casting and compocasting routes and their microstructural characteristics and hardness were examined. In order to ...alleviate the problems associated with poor wettability, agglomeration and gravity segregation of CNTs in the melt, CNTs were introduced into the melts by injection of CNT deposited aluminum particles instead of raw CNTs. Aluminum particles with mean diameters of less than 100μm were first deposited by CNTs using Ni-P electroless plating technique and then injected into the melt agitated by a mechanical stirrer. The slurry was subsequently cast at temperatures corresponding to full liquid as well as 0.15 and 0.30 solid fractions. The results show that addition of CNTs to A356 matrix can significantly refine both full liquid and semi-solid cast microstructures. Hardness of the samples is also significantly increased by addition of CNTs and A356-CNT composite cast at 0.3 solid fraction produces the highest hardness.
Water management in mountainous regions faces significant challenges due to deep uncertainties arising from data scarcity, knowledge gaps, and the complex interplay of climate and socio-economic ...changes. While existing approaches focused on uncertainty reduction and water system optimization contribute to managing uncertainties, they often require probability distributions that can be difficult to obtain in data-scarce mountain regions. To address these challenges, we demonstrate the effectiveness of Exploratory Modeling and Analysis (EMA) in assessing water management strategies and identifying operational ranges that avoid future water scarcity. Through a case study in the complex and data-scarce Peruvian Andes, we employed EMA to run 12,000 simulations by 2050, incorporating deep uncertainties from climate and socio-economic scenarios, and hydrological modeling parameters. This analysis identified specific policy combinations demonstrating greater robustness across diverse scenarios and uncertainties. EMA explicitly identifies operational ranges of policies to avoid water scarcity but also highlights the conditions that might trigger policy failure. We also delve into the roles of the different factors used in EMA and their significance in water management applications. Our research illustrates that an exploratory hydrological modeling approach based on robust decision-making can foster a more informed decision-making process for long-term water adaptation in rapidly changing mountain regions under data scarcity and deep uncertainties.
This work integrates a physics-based model with a data driven time-series model to forecast and optimally manage building energy. Physical characterization of the building is partially captured by a ...collection of zonal energy balance equations with parameters estimated using a least squares estimation (LSE) technique and data initially generated from the EnergyPlus building model. A generalized Cochran-Orcutt estimation technique is adopted to describe the data generated from these simulations. The combined forecast model is then used in a model predictive control (MPC) framework to manage heating and cooling set points. This work is motivated by the practical limitations of simulation-based optimizations. Once the forecast model is established capturing sufficient statistical variability and physical behavior of the building, there will be no more need to run EnergyPlus in the optimization routine. The proposed methodology lends itself for real-life implementation of building energy management systems where predictive control is desired to reduce energy use and avoid demand charges and occupant discomfort. At each time step, it determines the optimal set point values of all building's zones and updates these values over time. In practice, the proposed control strategy can be implemented in commercial smart energy boxes to optimally control total daily energy-use costs.
In this research, the wear of electroless Ni-P and Ni-P-B4C composite coatings was reviewed. Auto catalytic reduction of Ni in nickel sulfate and sodium hypophosphate bath including suspended B4C ...particles with different concentration was used to create composite coatings with 12, 18, 25 and 33 vol.% of B4C particles. Coatings 35 mm thick were heat treated at 400 deg C for one hour in an argon atmosphere and the wear resistance and friction coefficient of heat-treated samples were determined by block-on-ring tests. All wear tests were carried out at 24 deg C, 35% moisture, 0.164 m/s sliding speed and about 1000 m sliding distance. Graphs show that an electroless Ni-P-B4C composite coating with 25 vol.% of B4C had the best wear resistance against a CK45 steel counterface. Substrate: low carbon steel.
PDF
