Probabilistic cost-benefit analysis for mitigating hydrogeological risks in underground construction

Leakage of groundwater into underground facilities can subsequently cause groundwater drawdown, subsidence and subsidence damages to the built-up environment. In order to reduce the risk of damage, measures to mitigate the risks must often be implemented. The aim of this paper is to describe and demonstrate a probabilistic cost-benefit analysis approach to assess the economic profitability of investing in different risk mitigation alternatives. Since underground construction is always associated with uncertainties, the analysis uses probability distribution functions for uncertain parameters and Monte Carlo simulations to quantify probabilities of damage and implementation costs. The proposed approach is exemplified with a case study, the road tunnel project Bypass (F\uf6rbifart) Stockholm in eastern Sweden, for which four risk mitigation alternatives were evaluated. In conclusion, the approach helps to highlight the economic effects of different risk mitigation approaches and constitute a transparent support for decisions on implementation of risk mitigation. For the case study, the analysis indicates that the implementation costs of ∼ 7000 MSEK (700 million EUR) for risk mitigation needed to fulfil the legal requirements, from the Swedish Land- and Environmental court, in the form of ambitious sealing strategies are disproportionate relative to the benefits of ∼ 50 MSEK (5 million EUR) gained in the form of reduced damage risk for the built-up environment. In other words, billions SEK of taxpayers\u27 money are spent on unnecessary expenses to fulfill legal requirements without societal benefits. The novelty of the paper constitutes the coupling of models and combination of established methods for management of hydrogeological risks

A Framework for Risk-Based Cost-Benefit Analysis for Decision Support on Hydrogeological Risks in Underground Construction

Construction below the ground surface and underneath the groundwater table is often associated with groundwater leakage and drawdowns in the surroundings which subsequently can result in a wide variety of risks. To avoid groundwater drawdown-associated damages, risk-reducing measures must often be implemented. Due to the hydrogeological system\u27s inherent variability and our incomplete knowledge of its conditions, the effects of risk-reducing measures cannot be fully known in advance and decisions must inevitably be made under uncertainty. When implementing risk-reducing measures there is always a trade-off between the measures\u27 benefits (reduced risk) and investment costs which needs to be balanced. In this paper, we present a framework for decision support on measures to mitigate hydrogeological risks in underground construction. The framework is developed in accordance with the guidelines from the International Standardization Organization (ISO) and comprises a full risk-management framework with focus on risk analysis and risk evaluation. Cost-benefit analysis (CBA) facilitates monetization of consequences and economic evaluation of risk mitigation. The framework includes probabilistic risk estimation of the entire cause-effect chain from groundwater leakage to the consequences of damage where expert elicitation is combined with data-driven and process-based methods, allowing for continuous updating when new knowledge is obtained

Villkorsutformning f\uf6r grundvattenbortledning vid undermarksbyggande

Vid undermarksbyggande och under r\ue5dande grundvattenyta kan grundvatten l\ue4cka in i anl\ue4ggningen. Eftersom arbeten i anl\ue4ggningen samt driften av anl\ue4ggningen i regel m\ue5ste utf\uf6ras i torra milj\uf6er m\ue5ste inl\ue4ckande grundvatten i s\ue5dana situationer ledas bort. Grundvattenbortledning riskerar att skada ekonomiska, kulturella och milj\uf6m\ue4ssiga v\ue4rden. Bortledning av grundvatten och d\ue4rmed anl\ue4ggning av undermarkskonstruktioner kr\ue4ver i regel alltid tillst\ue5nd enligt milj\uf6balkens 11 kapitel. F\uf6r att s\ue4kerst\ue4lla att verksamheten uppfyller milj\uf6balkens m\ue5l och krav fastst\ue4lls vanligen villkor f\uf6r vattenverksamheten i tillst\ue5ndsdomen. Hur dessa villkor utformas kan ha stor p\ue5verkan p\ue5 ett projekts framdrift och utf\uf6rande d\ue5 verksamhetsut\uf6varen ofta m\ue5ste vidta dyra och tidskr\ue4vande \ue5tg\ue4rder f\uf6r att efterleva villkoren. En \uf6vertr\ue4delse av villkoren \ue4r ocks\ue5 straffr\ue4ttsligt sanktionerat. Det \uf6vergripande syftet med denna rapport \ue4r att beskriva sambandet mellan st\ue4llda villkor f\uf6r grundvattenbortledning vid undermarksbyggande och dessas konsekvenser i form av skador, st\uf6rningar och kostnads\uf6kningar. F\uf6r att uppn\ue5 detta syfte har milj\uf6balkens till\ue4mpning vid vattenverksamhet beskrivits utifr\ue5n en litteraturstudie, historiska tillst\ue5ndsdomar har analyserats f\uf6r att beskriva hur villkor har utformats i tidigare projekt, och ett arbetsseminarium med experter inom vattenverksamhet och undermarksbyggande har genomf\uf6rts f\uf6r att beskriva konsekvenserna av olika villkorskonstruktioner. Resultaten fr\ue5n arbetet visar att villkoren i tillst\ue5ndsdomen kan vara mycket kostnadsdrivande och ha stor p\ue5verkan p\ue5 b\ue5de ett undermarksprojekts ekonomi samt dess framdrift om dessa utformas p\ue5 ett of\uf6rdelaktigt s\ue4tt och inte \ue4r \ue4ndam\ue5lsenliga. Rapporten avslutas med rekommendationer f\uf6r hur villkor b\uf6r utformas f\uf6r att undvika eller minska risken f\uf6r dessa negativa konsekvenser

Element Replacement Approach by Reaction with Lewis Acidic Molten Salts to Synthesize Nanolaminated MAX Phases and MXenes

Nanolaminated materials are important because of their exceptional properties and wide range of applications. Here, we demonstrate a general approach to synthesize a series of Zn-based MAX phases and Cl-terminated MXenes originating from the replacement reaction between the MAX phase and the late transition metal halides. The approach is a top-down route that enables the late transitional element atom (Zn in the present case) to occupy the A site in the pre-existing MAX phase structure. Using this replacement reaction between Zn element from molten ZnCl2 and Al element in MAX phase precursors (Ti3AlC2, Ti2AlC, Ti2AlN, and V2AlC), novel MAX phases Ti3ZnC2, Ti2ZnC, Ti2ZnN, and V2ZnC were synthesized. When employing excess ZnCl2, Cl terminated MXenes (such as Ti3C2Cl2 and Ti2CCl2) were derived by a subsequent exfoliation of Ti3ZnC2 and Ti2ZnC due to the strong Lewis acidity of molten ZnCl2. These results indicate that A-site element replacement in traditional MAX phases by late transition metal halides opens the door to explore MAX phases that are not thermodynamically stable at high temperature and would be difficult to synthesize through the commonly employed powder metallurgy approach. In addition, this is the first time that exclusively Cl-terminated MXenes were obtained, and the etching effect of Lewis acid in molten salts provides a green and viable route to prepare MXenes through an HF-free chemical approach.Comment: Title changed; experimental section and discussion revise

Regulating Sustainable Finance in Capital Markets: A Perspective from Socially Embedded Decentered Regulation

We present an ab initio theoretical analysis of the temperature-dependent stability of inherently nanolaminated (Cr1−xMnx)2AlC. The results indicate energetic stability over the composition range x = 0.0 to 0.5 for temperatures ≥600 K. Corresponding thin film compounds were grown by magnetron sputtering from four elemental targets. X-ray diffraction in combination with analytical transmission electron microscopy, including electron energy-loss spectroscopy and energy dispersive x-ray spectroscopy analysis, revealed that the films were epitaxial (0001)-oriented single-crystals with x up to 0.16.Funding Agencies|European Research Council under the European Community|258509227754|Knut and Alice Wallenberg Foundation||Swedish Research Council|||DFG-SPP 1299|</p

Improved charge storage performance of a layered Mo1.33C MXene/MoS2/graphene nanocomposite

The construction of nanocomposite electrodes based on 2D materials is an efficient route for property enrichment and for exploitation of constituent 2D materials. Herein, a flexible Mo1.33C i-MXene/MoS2/graphene (MOMG) composite electrode is constructed, utilizing an environment-friendly method for high-quality graphene and MoS2 synthesis. The presence of graphene and MoS2 between MXene sheets limits the commonly observed restacking, increases the interlayer spacing, and facilitates the ionic and electronic conduction. The as-prepared MOMG electrode delivers a volumetric capacitance of 1600 F cm(-3) (450 F g(-1)) at the scan rate of 2 mV s(-1) and retains 96% of the initial capacitance after 15 000 charge/discharge cycles (10 A g(-1)). The current work demonstrates that the construction of nanocomposite electrodes is a promising route towards property enhancement for energy storage applications

DIMENSIONALITY BASED SCALE SELECTION IN 3D LIDAR POINT CLOUDS

International audienceThis papers presents a multi-scale method that computes robust geometric features on lidar point clouds in order to retrieve the optimal neighborhood size for each point. Three dimensionality features are calculated on spherical neighborhoods at various radius sizes. Based on combinations of the eigenvalues of the local structure tensor, they describe the shape of the neighborhood, indicating whether the local geometry is more linear (1D), planar (2D) or volumetric (3D). Two radius-selection criteria have been tested and compared for finding automatically the optimal neighborhood radius for each point. Besides, such procedure allows a dimensionality labelling, giving significant hints for classification and segmentation purposes. The method is successfully applied to 3D point clouds from airborne, terrestrial, and mobile mapping systems since no a priori knowledge on the distribution of the 3D points is required. Extracted dimensionality features and labellings are then favorably compared to those computed from constant size neighborhoods

Unraveling the optoelectronic properties of CoSbx intrinsic selective solar absorber towards high-temperature surfaces

The combination of the ability to absorb most of the solar radiation and simultaneously suppress infrared re-radiation allows selective solar absorbers (SSAs) to maximize solar energy to heat conversion, which is critical to several advanced applications. The intrinsic spectral selective materials are rare in nature and only a few demonstrated complete solar absorption. Typically, intrinsic materials exhibit high performances when integrated into complex multilayered solar absorber systems due to their limited spectral selectivity and solar absorption. In this study, we propose CoSbx (2 &lt; x &lt; 3) as a new exceptionally efficient SSA. Here we demonstrate that the low bandgap nature of CoSbx endows broadband solar absorption (0.96) over the solar spectral range and simultaneous low emissivity (0.18) in the mid-infrared region, resulting in a remarkable intrinsic spectral solar selectivity of 5.3. Under 1 sun illumination, the heat concentrates on the surface of the CoSbx thin film, and an impressive temperature of 101.7 degrees C is reached, demonstrating the highest value among reported intrinsic SSAs. Furthermore, the CoSbx was tested for solar water evaporation achieving an evaporation rate of 1.4 kg m(-2) h(-1). This study could expand the use of narrow bandgap semiconductors as efficient intrinsic SSAs with high surface temperatures in solar applications

High quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition

Aluminum-doped zinc oxide, ZnO:Al or AZO, is a well-known n-type transparent conducting oxide with great potential in a number of applications currently dominated by indium tin oxide (ITO). In this study, the optical and electrical properties of AZO thin films deposited on glass and silicon by pulsed filtered cathodic arc deposition are systematically studied. In contrast to magnetron sputtering, this technique does not produce energetic negative ions, and therefore ion damage can be minimized. The quality of the AZO films strongly depends on the growth temperature while only marginal improvements are obtained with post-deposition annealing. The best films, grown at a temperature of about 200?C, have resistivities in the low to mid 10-4 Omega cm range with a transmittance better than 85percent in the visible part of the spectrum. It is remarkable that relatively good films of small thickness (60 nm) can be fabricated using this method

Synthesis and characterization of Zr2Al3C4 thin films

Zr2Al3C4 is an inherently nanolaminated carbide where layers of ZrC alternatewith layers of Al3C2. Characterization of bulk samples has shown it has improved damage tolerance and oxidation resistance compared to its binary counterpart ZrC. Though a potential candidate for coatings applied for use in harsh environments, thin films of Zr2Al3C4 have not been reported.We have synthesized epitaxial Zr2Al3C4 thin films by pulsed cathodic arc deposition from three elemental cathodes, and have studied the effect of incident atomic flux ratio, deposition temperature, and choice of substrate on material quality. X-ray diffraction analysis showed that Zr2Al3C4 of the highest structural quality was obtained for growth on 4 H-SiC(001) substrate at 800 ^deg;C. Also, suppression of competing phases could be achieved on á-Al2O3(001) at elevated substrate temperatures. Very similar growth behavior to that of the well-known Mn+1AXn phases - Al supersaturation, binary carbide intergrowth and high sensitivity to choice of substrate - indicates a strong connection between the two families ofmaterials, despite their differences in structure and in chemistry