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1.
Groundwater depletion is arguably one of humanity's greatest sustainability challenges of the 21st century. With Sustainable Development Goals only a decade away, water authorities around the world are in the urgent need for concrete and targeted measures to ensure that communities adhere to groundwater management policies as rapidly and as effectively as possible. In this paper, we combine computational social science, groundwater modelling and empirical data from the World Values Survey to generate future ensembles of hydro-social trajectories under alternative courses of management and social action or inaction. Our simulations shed new light on the role that cultural values can play in shaping the societal trajectories and norms that emerge when resources are either allocated or not sufficiently allocated to monitor compliance, issue fines, engage community leaders, and deter rule-breakers. This study presents a new approach to explore and evaluate the capacity of existing and future management actions to steer groundwater systems towards sustainable trajectories, to forecast the celerity and timing of social transformations at the inter-decadal scale, and to help nations identify the most pertinent management options under institutional, political, social, and/or cultural constraints. The methods presented here are broadly applicable to support strategic decisions that rely on the monitoring, enforcement, and compliance of environmental regulations. 相似文献
2.
Implementation of a coupled plastic damage distinct lattice spring model for dynamic crack propagation in geomaterials 下载免费PDF全文
This paper studies dynamic crack propagation by employing the distinct lattice spring model (DLSM) and 3‐dimensional (3D) printing technique. A damage‐plasticity model was developed and implemented in a 2D DLSM. Applicability of the damage‐plasticity DLSM was verified against analytical elastic solutions and experimental results for crack propagation. As a physical analogy, dynamic fracturing tests were conducted on 3D printed specimens using the split Hopkinson pressure bar. The dynamic stress intensity factors were recorded, and crack paths were captured by a high‐speed camera. A parametric study was conducted to find the influences of the parameters on cracking behaviors, including initial and peak fracture toughness, crack speed, and crack patterns. Finally, selection of parameters for the damage‐plasticity model was determined through the comparison of numerical predictions and the experimentally observed cracking features. 相似文献
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The Northland region of New Zealand includes numerous high-value, macrophyte-dominated dune lakes. Recent water policy reforms offer limited guidance on managing for aquatic macrophytes. In addition, dune lake histories are poorly known as regular monitoring dates to 2005 AD. Here, ca. 4000 years of lake functional behaviour is reconstructed from sedimentary archives in two Northland dune lakes (Humuhumu and Rotokawau). Results demonstrated that macrophyte dominance is sensitive to catchment erosion and hydrological drawdown. Degradation of macrophyte communities occurred in the nineteenth and twentieth centuries, earlier at Lake Humuhumu than Lake Rotokawau (post-1880 AD and post-1930 AD, respectively). In both lakes, increased erosional influx reduced macrophyte productivity, before later increases to wider trophic state (post-1970 AD). Lake-level decline is linked to increased nutrient loading at Lake Rotokawau but less so, Lake Humuhumu which is more strongly groundwater-fed. In Northland dune lakes, water-level reduction and erosional influx from land use have driven macrophyte degradation. 相似文献
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Takuya Matsumoto Masahiko Honda Ian McDougall Igor Yatsevich Suzanne Y. O'Reilly 《地学学报》2004,16(1):23-26
Using a Rayleigh distillation fractionation model, we calculate that the maximum isotope fractionation potentially achievable is less than 5% during the early stages of gas release from a sample. Our calculation corrects the erroneous conclusions of Gautheron and Moreira (2003), who re‐interpreted the plume‐like neon isotopic compositions found in metasomatic apatite from a south‐eastern Australian xenolith (Matsumoto et al., 1997) to be the result of Rayleigh‐type isotope fractionation of originally MORB‐type neon during stepheating gas extraction. We stress that the modelling of neon isotopic fractionation by Gautheron and Moreira (2003) is incorrect, and that the finding of a plume‐like neon isotopic composition in the apatite by Matsumoto et al. (1997) remains a quite valid and robust conclusion. 相似文献
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《Coastal Engineering》2006,53(7):589-611
The results of a series of 2DH numerical and 3D scaled physical modelling tests indicate that processes governing shoreline response to submerged structures, such as artificial surfing reefs, are different from those associated with emergent offshore breakwaters. Unlike the case of emergent offshore breakwaters, where shoreline accretion (salient development) is expected under all structural/environmental conditions, the principal mode of shoreline response to submerged structures can vary between erosive and accretive, depending on the offshore distance to the structure. The predominant wave incidence angle and structure crest level also have important implications on the magnitude of shoreline response, but not on the mode of shoreline response (i.e. erosion vs. accretion). Based on the results obtained here, a predictive empirical relationship is proposed as a preliminary engineering tool to assess shoreline response to submerged structures. 相似文献
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Estela M. Reynoso † Simon Johnston Anne J. Green Bärbel S. Koribalski 《Monthly notices of the Royal Astronomical Society》2006,369(1):416-424
We have observed the supernova remnant (SNR) G290.1−0.8 in the 21-cm H i line and the 20-cm radio continuum using the Australia Telescope Compact Array (ATCA). The H i data were combined with data from the Southern Galactic Plane Survey to recover the shortest spatial frequencies. In contrast, H i absorption was analysed by filtering extended H i emission, with spatial frequencies shorter than 1.1 kλ. The low-resolution ATCA radio continuum image of the remnant shows considerable internal structure, resembling a network of filaments across its 13-arcmin diameter. A high-resolution ATCA radio continuum image was also constructed to study the small-scale structure in the SNR. It shows that there are no structures smaller than ∼17 arcsec, except perhaps for a bright knot to the south, which is probably an unrelated object. The H i absorption study shows that the gas distribution and kinematics in front of SNR G290.1−0.8 are complex. We estimate that the SNR probably lies in the Carina arm, at a distance 7 (±1) kpc. In addition, we have studied nearby sources in the observed field using archival multiwavelength data to determine their characteristics. 相似文献
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