Methodological evolution and frontiers of identifying, modeling and preventing secondary crashes on highways

© 2018 Elsevier Ltd Secondary crashes (SCs) or crashes that occur within the boundaries of the impact area of prior, primary crashes are one of the incident types that frequently affect highway traffic operations and safety. Existing studies have made great efforts to explore the underlying mechanisms of SCs and relevant methodologies have been e volving over the last two decades concerning the identification, modeling, and prevention of these crashes. So far there is a lack of a detailed examination on the progress, lessons, and potential opportunities regarding existing achievements in SC-related studies. This paper provides a comprehensive investigation of the state-of-the-art approaches; examines their strengths and weaknesses; and provides guidance in exploiting new directions in SC-related research. It aims to support researchers and practitioners in understanding well-established approaches so as to further explore the frontiers. Published studies focused on SCs since 1997 have been identified, reviewed, and summarized. Key issues concentrated on the following aspects are discussed: (i) static/dynamic approaches to identify SCs; (ii) parametric/non-parametric models to analyze SC risk, and (iii) deployable countermeasures to prevent SCs. Based on the examined issues, needs, and challenges, this paper further provides insights into potential opportunities such as: (a) fusing data from multiple sources for SC identification, (b) using advanced learning algorithms for real-time SC analysis, and (c) deploying connected vehicles for SC prevention in future research. This paper contributes to the research community by providing a one-stop reference for research on secondary crashes

Optimising railcar transfer chain via fuzzy programming and a simulated annealing algorithm

With the accelerated changes of trade and economic structure, the fluctuation of shipment size is increasing in railway transportation. Railway companies are facing continuous challenges about how to optimise railcar transfer chain to achieve the balance between the workload of railway network and daily changing transportation demands. In this paper, elastic capacity constraints are designed to solve the number fluctuation of railcars in shipments. We define available capacity belts to describe the elastic capacities of railway network, then fuzzy theory is introduced. A membership function is designed to designate the satisfaction degree for the number of railcars, and a non-linear integer programming model is developed. We test the model with two numerical examples from the 2019 Railway Applications Section Problem Solving Competition, and a simulated annealing algorithm is employed to solve the problem. In the experiment with 16 yards, the model generated 1304 variables. Furthermore, as the scale of the railway network increases, the number of variables exhibited exponential explosive growth. In the experiment with 32 yards, the model generated 76,037 variables and determined 365 direct train services, resulting in an operating cost of 245,014,388 car-hours. The results of the experiments effectively verify the effectiveness of the model.</p

MOESM1 of Gravity analysis of the offset between crustal structure and topography in the Liupan Shan, northeast Tibetan Plateau

Additional file 1. Topography and reference models of profile DD’ from Bao et al. (2013) and profiles P1–3. Numbers indicate the densities (g/cm3) of each layer. The reference models of profiles P1–2 are derived from the “profile propagation” method and that of P3 is interpolated from the inverted models. The differences between inverted and reference model of each profile are small for the reason that we require these models to be close

Mapping cumulative impacts of mining on sediment retention ecosystem service in an Australian mining region

Mining development can potentially lead to cumulative impacts on ecosystems and their services across a range of scales. Site-specific environmental impact assessments are commonly assessed for mining projects; however, large-scale cumulative impacts of multiple mines that aggregate and interact in resources regions have had little attention in the literature and there are few examples where regional-scale mining impacts have been assessed on ecosystem services. The objective of this study is to quantify regional-scale cumulative impacts of mining on sediment retention ecosystem services. We apply the sediment delivery ratio model of Integrated Valuation of Ecosystem Services and Trade-offs to calculate and map the sediment retention and export using a synthetic catchment model and a real case study under different mining scenarios in an Australian mining region. Two impact indices were created to quantify the cumulative impacts associated with a single mine and the interactions between multiple mines. The indices clarified the magnitude of impacts and the positive/negative impacts associated with regional-scale sediment retention and export. We found cumulative impacts associated with multiple mines’ interaction occurred but the influence of these interactions was relatively weak. This research demonstrated the potential for utilising ecosystem services modelling for the quantitative assessment of the cumulative impacts. Such research provide decision-makers and planners with a tool for sustainable regional and landscape planning that balances the needs of mining and the provision of ecosystem services.</p

Ecosystem Services Mapping Uncertainty Assessment: A Case Study in the Fitzroy Basin Mining Region

Ecosystem services mapping is becoming increasingly popular through the use of various readily available mapping tools, however, uncertainties in assessment outputs are commonly ignored. Uncertainties from different sources have the potential to lower the accuracy of mapping outputs and reduce their reliability for decision-making. Using a case study in an Australian mining region, this paper assessed the impact of uncertainties on the modelling of the hydrological ecosystem service, water provision. Three types of uncertainty were modelled using multiple uncertainty scenarios: (1) spatial data sources; (2) modelling scales (temporal and spatial) and (3) parameterization and model selection. We found that the mapping scales can induce significant changes to the spatial pattern of outputs and annual totals of water provision. In addition, differences in parameterization using differing sources from the literature also led to obvious differences in base flow. However, the impact of each uncertainty associated with differences in spatial data sources were not so great. The results of this study demonstrate the importance of uncertainty assessment and highlight that any conclusions drawn from ecosystem services mapping, such as the impacts of mining, are likely to also be a property of the uncertainty in ecosystem services mapping methods.</p

Layered Hexagonal Oxycarbides, M_<i>n</i>+1AO₂X_<i>n</i> (M = Sc, Y, La, Cr, and Mo; A = Ca; X = C): Unexpected Photovoltaic Ceramics

A family of layered hexagonal oxycarbides and oxynitrides with the general formula, Mn+1AO2Xn (MAOX) is discovered using first-principles DFT calculations, where n = 1–3, M is an early transition metal, A is an alkaline earth metal in Group IIA or a late transition metal in Groups IB and IIB, X is C and/or N. Thermodynamically, the MAOX phases are very stable. Tuning the composition, MAOX can be metals, semimetals, or semiconductors. To date, five 2121 oxycarbide MAOX phases, M2CaO2C (M = Sc, Y, La, Cr, and Mo), are found to be semiconductors with band gaps from 0.39 to 1.14 eV. To our strong surprise, they have superior photovoltaic (PV) properties and their theoretical solar cell efficiencies are on par with GaAs. In particular, the efficiency of Cr2CaO2C reaches 27.7%, which is above 90% of the Schottky–Queisser (SQ) limit. Furthermore, amazingly, the five MAOX semiconductors possess outstanding strength and machinability, e.g., their Young’s moduli are comparable to ceramics and MAX phases, and Poisson’s ratios higher than MAX and even comparable to metals. MAOX semiconductors are promising multifunctional ceramics. The unique combination of the photovoltaic and mechanical properties will certainly enable the MAOX semiconductors to find broad applications in the photovoltaic industry

Ecosystem Services Mapping Uncertainty Assessment: A Case Study in the Fitzroy Basin Mining Region

Ecosystem services mapping is becoming increasingly popular through the use of various readily available mapping tools, however, uncertainties in assessment outputs are commonly ignored. Uncertainties from different sources have the potential to lower the accuracy of mapping outputs and reduce their reliability for decision-making. Using a case study in an Australian mining region, this paper assessed the impact of uncertainties on the modelling of the hydrological ecosystem service, water provision. Three types of uncertainty were modelled using multiple uncertainty scenarios: (1) spatial data sources; (2) modelling scales (temporal and spatial) and (3) parameterization and model selection. We found that the mapping scales can induce significant changes to the spatial pattern of outputs and annual totals of water provision. In addition, differences in parameterization using differing sources from the literature also led to obvious differences in base flow. However, the impact of each uncertainty associated with differences in spatial data sources were not so great. The results of this study demonstrate the importance of uncertainty assessment and highlight that any conclusions drawn from ecosystem services mapping, such as the impacts of mining, are likely to also be a property of the uncertainty in ecosystem services mapping methods.</p

Mapping cumulative impacts of mining on sediment retention ecosystem service in an Australian mining region

Mining development can potentially lead to cumulative impacts on ecosystems and their services across a range of scales. Site-specific environmental impact assessments are commonly assessed for mining projects; however, large-scale cumulative impacts of multiple mines that aggregate and interact in resources regions have had little attention in the literature and there are few examples where regional-scale mining impacts have been assessed on ecosystem services. The objective of this study is to quantify regional-scale cumulative impacts of mining on sediment retention ecosystem services. We apply the sediment delivery ratio model of Integrated Valuation of Ecosystem Services and Trade-offs to calculate and map the sediment retention and export using a synthetic catchment model and a real case study under different mining scenarios in an Australian mining region. Two impact indices were created to quantify the cumulative impacts associated with a single mine and the interactions between multiple mines. The indices clarified the magnitude of impacts and the positive/negative impacts associated with regional-scale sediment retention and export. We found cumulative impacts associated with multiple mines’ interaction occurred but the influence of these interactions was relatively weak. This research demonstrated the potential for utilising ecosystem services modelling for the quantitative assessment of the cumulative impacts. Such research provide decision-makers and planners with a tool for sustainable regional and landscape planning that balances the needs of mining and the provision of ecosystem services.</p

In–Ni Intermetallic Compounds Derived from Layered Double Hydroxides as Efficient Catalysts toward the Reverse Water Gas Shift Reaction

Intermetallic compounds (IMCs) are widely employed in heterogeneous catalysis. In this paper, the performance and mechanism of In–Ni IMCs with different structures (InNi3, InNi2, InNi, and In3Ni2) in the reverse water gas shift (RWGS) reaction are reported. In situ spectroscopic and microscopic characterizations combined with density functional theory (DFT) calculation demonstrated that the increase of the In/Ni ratio in IMCs enhanced the selectivity of CO by inhibiting the adsorption of CO* via “active site isolation.” Ni, as the active site of the CO2 hydrogenation reaction, was isolated by In in In–Ni IMCs. Meanwhile, DFT calculation revealed that CO2 hydrogenation preferentially produced CO rather than CH4 and/or CH3OH, and the reaction path for the RWGS reaction is the redox path over the In–Ni IMC. At 500 °C, the catalyst achieved a 99.8% CO selectivity at a CO2 conversion of 50.7% for more than 250 h without any deactivation, rendering it a promising candidate for industrial application

Presentation1_Gold nanoplatform for near-infrared light-activated radio-photothermal gas therapy in breast cancer.pdf

Although radiotherapy is one of the most common treatments for triple-negative breast cancer (TNBC), it frequently has unsatisfactory therapeutic outcomes due to the radiation resistance of tumor tissues. Therefore, a synergistic strategy is urgently needed to increase therapeutic responses and prolong patient survival. Herein, we constructed gold nanocages (GNCs) loaded with a hyperpyrexia-sensitive nitric oxide (NO) donor (thiolate cupferron) to integrate extrinsic radiosensitization, local photothermal therapy, and near-infrared-activated NO gas therapy. The resulting nanoplatform (GNCs@NO) showed a high photothermal conversion efficiency, which induced the death of cancer cells and facilitated rapid NO release in tumor tissues. The radiosensitizing efficacy of GNCs@NO was further demonstrated in vitro and in vivo. Importantly, the released NO reacted with the reactive oxide species induced by radiotherapy to produce more toxic reactive nitrogen species, exerting a synergistic effect to improve anticancer efficacy. Thus, GNCs@NO demonstrated excellent effects as a combination therapy with few adverse effects. Our work proposes a promising nanoplatform for the radio/photothermal/gas treatment of TNBC.</p