查看更多>>摘要：Infrastructure resilience is quite an emerging topic that has captured tremendous interest among researchers and practitioners. Resilience of water distribution networks (WDNs) established itself as one of the most promising and growing hotspots in the realm of sustainable management against extreme hazards. This study aims to delve into the manifestation, genesis, progression, and gaps of the resilience research related to WDNs. The study comprises a meticulous quantitative and qualitative delineation of 184 articles between 2000 and 2021 utilizing a combination of bibliometric analysis and systematic review. Network analysis (co-word, co-citation, co-author, and clustering) was employed to determine and visualize the prominent topics, influential publications, citation patterns, and productive authors and countries along with their interconnections. Subsequently, text mining tools and critical content analysis were adopted to explore extant research characteristics and gaps. Three thematic clusters were identified 1) hydraulic simulation for resilience assessment, 2) surrogate measures and comparative studies, and 3) connectivity and topological metrics. A bias in the research literature towards classical resilience assessment overlooking organizational, adaptive, and interdependency aspects was reported. The in-depth understanding provided in this study is expected to unlock new research and investment opportunities in the domain of WDNs resilience.
查看更多>>摘要：The stochastic simulation of deltas has always been one of the significant problems in the numerical simulation of reservoirs. Three problems of deltaic simulations are non-stationary geological characteristics in training images (TIs), insufficient quantity of TIs in certain regions and unavailable reuse of training parameters and models even after the first training, which have caused big challenges for the stochastic simulation of deltas especially in the circumstances of only heterogeneous TIs are available and the simulation quantity is quite large. As one of the important numerical methods for the simulation of deltas, multiple-point statistics (MPS) obtains the statistical characteristics through the patterns in TIs to perform simulation. However, due to the non-stationarity of deltaic TIs, the traditional MPS cannot extract the non-stationary characteristics of TIs smoothly and is incapable of reusing the extracted probability information, making the simulation process quite time-consuming if multiple simulations are performed successively. Thanks to the powerful feature extraction capability brought by deep learning, the delta simulation possibly will be largely improved. The generative adversarial network (GAN) is an important deep learning method for image generation, but it needs large-quantity training samples and its training process is unstable, but another famous neural network variational auto-encoder (VAE) is more stable. On the other hand, VAE-generated images are often a little blurred but GAN-generated images are clearer. Therefore, based on VAE, GAN and a multi-stage idea, a concurrent multi-stage VAE-GAN model is proposed for the stochastic simulation of deltas to hopefully address the three problems in deltaic simulation by concurrently performing multi-stage simulation based on GAN and VAE. The comparison of our method with some typical MPS methods and deep learning methods has shown its good performance in deltaic simulation.
查看更多>>摘要：A new solution for advective-dispersive solute transport is developed for three-dimensional aquifer of finite thickness and width, infinite extent along the direction of flow, dual porosity, equilibrium linear sorption and first-order decay of both the sorbed and dissolved mass with coefficients that may differ in the mobile and immobile domains, and with initial concentration distribution or with source represented by a volumetric mass generation term of arbitrary time-dependence. The analytical Laplace domain solution is numericaly inverted into the time domain. The model is benchmarked against MT3DMS and simpler analytical models. The model is sensitive to transport parameters describing the dual domain, suggesting it may be used for evaluating tracer tests. The model is suitable for checking accuracy of numerical models and identifying ranges of key transport parameters.
查看更多>>摘要：Traditional centralized water-management systems have tended to fall short in delivering environmental and amenity benefits in urban areas. Water-sensitive urban design (WSUD) projects have been proposed as an alternative due to their ability to generate multiple benefits, including improving water quality, water supply, aesthetics, urban cooling, spaces for recreation, and habitat for biodiversity. However, in most cities, investment in such systems has been relatively low, in part due to the difficulty of monetizing the multifunctional benefits of WSUD projects and including them in comprehensive economic analyses. We describe the development, testing and application of INFFEWS (Investment Framework For the Economics of Water Sensitive cities), an economic decision-support system for investment in WSUD projects. INFFEWS is based on a Benefit: Cost Analysis (BCA) framework and is consistent with standard BCA. A prominent feature of the framework is its strong emphasis on quantifying the monetary-equivalent values of intangible (non-market) benefits from WSUD projects. Development of the tools and their supporting materials has involved extensive consultation with intended users, review of existing tools, and primary research over eight years (2013-2020). The frameworks can be applied to businesscase development and decision making at multiple levels in public-sector and private-sector organisations.
查看更多>>摘要：This paper considers overland flow resistance at low Reynolds numbers through analysis of experimental runs carried out using water only and water/glycerol mixtures. We first examined the power relationship between the Darcy-Weisbach friction factor f and the Reynolds number Re to obtain the values of the K coefficient and b exponent. These results confirmed the applicability of the values of b suggested in literature, while K required a specific calibration for laminar open-channel flows. The analysis revealed that transition from a laminar to turbulent flow regime for water only flows occurred at a threshold value of Re equal to 500 as described historically. The estimate of f by the power relationship and the calibrated b and K values were reliable for water only runs when Re >= 500. The measurements were also used to test a theoretical flow resistance law based on a power-velocity distribution. The calibrated theoretical relationship between the velocity profile parameter gamma(v), bed slope, flow Froude number and Re enabled a good estimate off for water flows. For mixed fluid flows, the effect of the velocity profile shape was considered calibrating this relationship by two datasets obtained setting a threshold Reynolds number equal to 7. For flows with Re < 7, the shape of the velocity profile can be linear or convex while for flows at Re >= 7 the shape of the velocity distribution is always concave. The theoretical flow resistance allowed an accurate estimate also for mixed fluid flows, even at Re < 7. The different shape of the power-velocity distribution highlighted that mixed flows behave differently as compared to water only flows.
查看更多>>摘要：The extent of coastal flooding is influenced by many factors such as the topography of the low-lying land, tidal level, rainfall pattern, inflow discharge collected from the upstream drainage area, etc. This study establishes a new methodology of effectively predicting the flooding process in coastal areas, and which is achieved by combining the recurrent neural network (RNN) model with the detailed analysis of different hydrological and geomorphological factors. The novelty of this study is to apply the topographic wetness index (TWI) of each grid to classify all inputs into multiple classes for separative training to improve the overall accuracy of flooding simulations. A numerical inundation model based on hydrodynamic equations was applied to investigate the behavior of coastal flooding in the temporal and spatial domain under a variety of model settings with different hydrologic conditions and it was utilized to generate the target inundation depths for the training of the RNN model. The relevance between the downstream topography, tidal level, rainfall intensity, and the spatial distribution of flooding in coastal areas is explored via the use of machine learning (ML) techniques. The focus of this study is to evaluate the proposed alternative method that allows for improving the efficiency and stability of forecasting coastal floods caused by rains and storm surges due to the approaching tropical cyclones. The method developed in this study is promising to replace the numerical inundation model to reinforce the model's stability and computational efficiency.
查看更多>>摘要：Thoroughly understanding the security of water, energy and food (WEF) and the factors that influence them is essential for sustainable development management in any region. This study proposed a new analytical framework for WEF security evaluation in both individual sectors and the whole system, using the technique for order preference by similarity to an ideal solution (TOPSIS) and four dimensions of security indicators: availability, self-sufficiency, productivity and accessibility. The internal relationships among the three sectors and the main factors influencing WEF security were analysed by Spearman's rank correlation and radar graphs, respectively. The five countries in Central Asia (CA), which are experiencing WEF crises and facing great challenges in achieving their sustainable development goals (SDGs), were chosen as a case study in this paper. Our results showed that Kazakhstan attained the highest WEF security level, followed by Kyrgyzstan, Turkmenistan and Uzbekistan; Tajikistan exhibited the lowest security level from 2000 to 2014. Three types of internal relationships among the three sectors were identified: synergies, trade-offs and unclassified. The unclassified relationship type accounted for the largest share of 54% in CA, suggesting great potential for synergetic improvement among the three sectors. Approaches for improving the country WEF security based on our research are as follows: Kazakhstan should prioritize food allocation and supply, Kyrgyzstan and Tajikistan should increase energy and food production and raise the supply level and usage efficiency of water and food, Turkmenistan should increase the available water resources and food production and improve the supply level and usage efficiency of water and energy, and Uzbekistan should both increase the available amount and enhance the WEF management performance.
查看更多>>摘要：Fractures have a governing effect on the physical properties of fractured rocks, such as permeability. Accurate representation of 3D fractures is, therefore, required for precise analysis of digital fractured rocks. However, conventional segmentation methods fail to detect and label the fractures with aperture sizes near or below the resolution of 3D micro-computed tomographic (micro-CT) images, which are visible in the greyscale images, and where greyscale intensity convolution between different phases exists. In addition, conventional methods are highly subjective to user interpretation. Herein, a novel algorithm for the automatic detection of fractures from greyscale 3D micro-CT images is proposed. The algorithm involves a low-level early vision stage, which identifies potential fractures, followed by a high-level interpretative stage, which enforces planar continuity to reject false positives and more reliably extract planar fractures from digital rock images. A manually segmented fractured shale sample was used as the groundtruth, with which the efficacy of the algorithm in 3D fracture detection was validated. Following this, the proposed and conventional methods were applied to detect fractures in digital fractured coal and shale samples. Based on these analyses, the impact of fracture detection accuracy on the analysis of fractured rocks' physical properties was inferred.
Abdalla, Elhadi Mohsen HassanAlfredsen, KnutMuthanna, Tone Merete
13页
查看更多>>摘要：Conceptual rainfall-runoff models (CRRMs) can be used as a design tool for green roofs due to their simplicity and acceptable accuracy. This study showed how the uncertainty of CRRM parameters could be reduced by changing the calibration practice, which can enhance the interpretation and identifiability of CRRM parameters. A CRRM was developed and tested on a dataset of 14 extensive green roofs located in four Norwegian cities with different climatic conditions. Two calibration schemes were compared: a common scheme using runoff data as a basis for calibration (single-objective), and a scheme combining runoff and soil moisture data for the calibration (multi-objective scheme). The results confirmed the ability of the CRRM to simulate runoff from extensive green roofs across multiple climatic zones and different roof configurations (Kling Gupta Efficiency > 0.75). The multiobjective calibration scheme was found to reduce the uncertainty of the CRRM parameters, especially the storage parameters, enhancing the physical interpretation of parameter values. The study attempted to give guidelines to estimate parameters of the CRRM which can be used by practitioners for new roof configurations under different climatic conditions.
查看更多>>摘要：To discuss the effects of discharge on the velocity distribution and riverbed evolution in a meandering river, a generalized meandering channel model was designed, and the instantaneous velocities and water levels in thirteen cross-sections and the digital elevations of the bed surfaces were measured. The results show that for the same discharge, the transverse water surface gradients are large at the downstream positions adjacent to the apex sections and small near the middle positions of the crossover areas. With increasing discharge, the transverse water surface gradients in the curved segments increase, the transverse underflows strengthen, and the transverse surface flows exhibit no obvious changes. If the curvature of a meandering channel is large and there are a large number of sediment particles whose incipient velocities are smaller than the transverse underflow velocities near the apex sections, then the regions between the apex-sectional convex sides and the outlets of the adjacent downstream crossover areas are prone to sediment deposition, and the frequency distributions of the bed surface elevations are positively skewed. For the same cross-section, the cross-sectional average velocity increases with increasing discharge. For the same discharge, the cross-sectional average velocities are large near the middle positions of the crossover areas and small near the apex sections. The thalweg swings randomly along the channel, but its overall trend is approximately the same as that of the flow dynamic axis. In a cross-section, the positions with large turbulent kinetic energy are located in the mainstream area, and the average turbulent kinetic energy increases with increasing discharge.
NSTL
Elsevier