Bio-economic evaluation of implementing trawl fishing gear with different selectivity

The paper develops a biological-economic evaluation tool to analyse the consequences for trawl fishers of implementing more selective fishing technologies. This is done by merging a dynamic biological population model and an economic cost–benefit evaluation framework to describe the consequences for the fish stocks, fishermen and society. The bio-economic evaluation is applied to the case of the Danish trawl fishery in Kattegat and Skagerrak, which experiences a high level of discards and bycatches of several species. Four different kinds of selectivity scenarios are evaluated in comparison with a baseline. The results from the evaluation are indicators for the consequences on ecological and economic levels. The results show that implementation of different selective fishing gear in the Kattegat and Skagerrak mixed trawl fisheries generally implies a trade off over time between rebuilding the stocks and economic loss. Moreover, the analysis shows that implementation of more selective gear is not always beneficial.     

Inter‐organisational communication in civil–military cooperation during complex emergencies: a case study in Afghanistan1

This paper seeks to contribute to an improved information management and exchange between humanitarian organisations and military agents in complex emergencies. To do so, a theoretical information management process model was developed and applied to the case of information management between International Security Assistance Force troops and humanitarian organisations such as Cordaid, DACAAR and the International Office for Migration in Kabul, Afghanistan. Based on this analysis the main shortcomings and problems in each stage of the information management process were identified. These include a lack of structured information databases, the absence of identification of information needs, and an over‐classification of documents by the military. Using a logical framework analysis, six major improvement tactics were developed, including the creation of more overlap in rotations of personnel, the specification of aims and tasks regarding information management, the improvement of skills and competences of personnel involved, and the introduction of regular joint civil–military evaluations.     

Combined effects of initial pressure and turbulence on explosions of hydrogen-enriched methane/air mixtures

Hydrogen-enrichment has been proposed as a useful method to overcome drawbacks (local flame extinction, combustion instabilities, lower power output, etc.) associated to turbulent premixed combustion of natural gas in both stationary and mobile systems. For the safe use of hydrogen-enriched hydrocarbon fuels, explosion data are needed.In this work, a comparative experimental study of the explosion behavior of stoichiometric hydrogen-enriched methane/air (with 10% of hydrogen molar content in the fuel) and pure methane/air mixtures is presented. Tests were carried out in a 5 l closed cylindrical vessel at different initial pressures (1, 3 and 6 bar), and starting from both quiescent and turbulent conditions.Results allow quantifying the combined effects of hydrogen substitution to methane, pressure and turbulence on maximum pressure, maximum rate of pressure rise, burning velocity and Markstein lengths.     

Two modelling approaches to water-quality simulation in a flooded iron-ore mine (Saizerais, Lorraine, France): a semi-distributed chemical reactor model and a physically based distributed reactive transport pipe network model

The flooding of abandoned mines in the Lorraine Iron Basin (LIB) over the past 25 years has degraded the quality of the groundwater tapped for drinking water. High concentrations of dissolved sulphate have made the water unsuitable for human consumption. This problematic issue has led to the development of numerical tools to support water-resource management in mining contexts. Here we examine two modelling approaches using different numerical tools that we tested on the Saizerais flooded iron-ore mine (Lorraine, France). A first approach considers the Saizerais Mine as a network of two chemical reactors (NCR). The second approach is based on a physically distributed pipe network model (PNM) built with EPANET 2 software. This approach considers the mine as a network of pipes defined by their geometric and chemical parameters. Each reactor in the NCR model includes a detailed chemical model built to simulate quality evolution in the flooded mine water. However, in order to obtain a robust PNM, we simplified the detailed chemical model into a specific sulphate dissolution-precipitation model that is included as sulphate source/sink in both a NCR model and a pipe network model. Both the NCR model and the PNM, based on different numerical techniques, give good post-calibration agreement between the simulated and measured sulphate concentrations in the drinking-water well and overflow drift. The NCR model incorporating the detailed chemical model is useful when a detailed chemical behaviour at the overflow is needed. The PNM incorporating the simplified sulphate dissolution-precipitation model provides better information of the physics controlling the effect of flow and low flow zones, and the time of solid sulphate removal whereas the NCR model will underestimate clean-up time due to the complete mixing assumption. In conclusion, the detailed NCR model will give a first assessment of chemical processes at overflow, and in a second time, the PNM model will provide more detailed information on flow and chemical behaviour (dissolved sulphate concentrations, remaining mass of solid sulphate) in the network. Nevertheless, both modelling methods require hydrological and chemical parameters (recharge flow rate, outflows, volume of mine voids, mass of solids, kinetic constants of the dissolution-precipitation reactions), which are commonly not available for a mine and therefore call for calibration data.     

海洋环境水下采油树腐蚀与防护研究进展

根据国内外水下采油树腐蚀防护技术现状,从采油树腐蚀环境、材料选择、阴极保护及涂层防护方面系统地探究了水下采油树的腐蚀防护技术,对各种技术的优缺点进行了比较分析.材料选择方面,主要对采油树的服役环境、服役要求及材料性能等进行了探究,并对常见水下采油树的材料316L、25Cr7Ni4Mo型双相不锈钢、30CrMo钢及Inconel 625等进行了分析总结.阴极保护方面,主要探究了牺牲阳极在采油树腐蚀与防护方面的应用.涂层防护方面,主要对国内外水下采油树重防腐涂层现状、标准及种类进行了综述分析.腐蚀失效方面,对其失效原因及失效分析原则和程序进行了探究.最后,就采油树的腐蚀防护材料选择、阴极保护、涂层防护及腐蚀失效方面的发展进行了展望.     

Comparison of the solution behaviour of a pyrite-calcite mixture in batch and unsaturated sand column

A successful application of reaction transport algorithms to calculate the chemical evolution of natural systems requires accurate methods to compute the rates of mineral/fluid surface reactions. Regarding the transport of radio-nuclides in mining dumps the dissolution of minerals is of special importance. Using a kinetic rate law of the mineral dissolution verified for unsaturated conditions will allow a realistic modelling of the mineral weathering in the environment. Dissolution rates of minerals in an aqueous solution are determined by several characteristics. These are surface reaction rates, morphology of the mineral's surface and, in case it is the unsaturated zone, the degree of the water saturation. For this process, the quantity of the particle surfaces which are in contact with percolating water is most decisive. In order to study the differences of mineral dissolution under saturated and unsaturated conditions batch and column experiments were carried out with a pyrite-calcite mixture. The experimental results were verified by calculations. Comparing the dissolution in batch with those in the column experiment, which was performed with a water flow velocity of 0.64 cm/day and was analyzed in the region of a water saturation of 0.11, one can conclude that only a small portion of about 5% of the grain surface is chemically reactive in this unsaturated flow.     

Characteristics and applications of controlled-release KMnO4 for groundwater remediation

In situ chemical oxidation (ISCO) using potassium permanganate (KMnO4) has been widely used as a practical approach for remediation of groundwater contaminated by chlorinated solvents like trichloroethylene. The most common applications are active flushing schemes, which target the destruction of some contaminant source by injecting concentrated permanganate (MnO4(-)) solution into the subsurface over a short period of time. Despite many promising results, KMnO4 flushing is often frustrated by inefficiency associated with pore plugging by MnO2 and bypassing. Opportunities exist for the development of new ISCO systems based on KMnO4. The new scheme described in this paper uses controlled-release KMnO4 (CRP) as an active component in the well-based reactive barrier system. This scheme operates to control spreading of a dissolved contaminant plume. Prototype CRP was manufactured by dispersing fine KMnO4 granules in liquid crystal polymer resin matrix. Scanning electron microscope data verified the formation of micro-scale (ID=20-200 microm) secondary capillary permeability through which MnO4(-) is released by a reaction-diffusion process. Column and numerical simulation data indicated that the CRP could deliver MnO4(-) in a controlled manner for several years without replenishment. A proof-of-concept flow-tank experiment and model simulations suggested that the CRP scheme could potentially be developed as a practical approach for in situ remediation of contaminated aquifers. This scheme may be suitable for remediation of sites where accessibility is limited or some low-concentration contaminant plume is extensive. Development of delivery systems that can facilitate lateral spreading and mixing of MnO4(-) with the contaminant plume is warranted.     

Application of a DPSIR Modeling Framework to Assess Spatial–Temporal Differences of Water Poverty in China

Water shortage is a common problem around the world, especially in developing countries. Water shortage is closely linked to natural and social conditions, but the linkages between these natural and social conditions and their underlying temporal and spatial variation are less well explored. This paper details an application of the Driving‐Force‐Pressure‐State‐Impact‐Response (DPSIR) model, a holistic and sustainable tool for resources planning and management, and uses comprehensive weights to evaluate the water poverty (wp) in China from 1997 to 2014. This study applies the Kernel density estimation model to analyze the temporal variation trend and uses the least square error model to analyze the spatial pattern of wp. The results show the level of wp is gradually declining over time and the improvements in the coastal and inland wp situation are not spatially harmonious, and there are four primary types of wp in China based on drivers and causal mechanisms: D‐P‐I, D‐P‐I‐R, D‐P‐S‐I, and D‐P‐S‐I‐R. Furthermore, we analyze the main causes of spatial difference of wp and put forward corresponding countermeasures. The research findings are intended to provide a new insight for the evaluation of wp in the context of sustainable development, breaking past limitations that arise in simplified analyses using a single method, and to provide a strategy for regional water resources management to relieve wp.     

The impact of preventive coping on business travelers' work and private life

Frequent business travel can be a burden for travelers' work and private life. We tested whether preventive coping (the proactive accumulation of resources in advance of potential stressors) makes such trips beneficial despite their potential to be stressful. In a longitudinal three‐wave study, we investigated whether frequent travel relates to an increase or decrease in work–life balance, emotional exhaustion, work engagement, and relationship satisfaction depending on preventive coping. Findings from a sample of 133 frequent business travelers revealed significant indirect effects for emotional exhaustion, work engagement, and relationship satisfaction through work–life balance. Among employees who engaged less in preventive coping, a higher number of business trips was related to a decrease in work–life balance, which, in turn, was related to more emotional exhaustion, less work engagement, and lower relationship satisfaction. Among those who reported higher preventive coping, we found opposing indirect effects: Frequent travel was related to an increase in work–life balance and, in turn, to less emotional exhaustion, more work engagement, and higher relationship satisfaction. These findings advance our knowledge in the field of business travel, future‐oriented coping, and work–life balance. They highlight that travelers and their organizations should resort to preventive coping to make frequent travel more beneficial.     

Societal individualism–collectivism and uncertainty avoidance as cultural moderators of relationships between job resources and strain

The job demands–resources model is a dominant theoretical framework that describes the influence of job demands and job resources on employee strain. Recent research has highlighted that the effects of job demands on strain vary across cultures, but similar work has not explored whether this is true for job resources. Given that societal characteristics can influence individuals' cognitive structures and, to a lesser extent, values in a culture, we address this gap in the literature and argue that individuals' strain in reaction to job resources may differ across cultures. Specifically, we theorize that the societal cultural dimensions of individualism–collectivism and uncertainty avoidance shape individual‐level job resource–strain relationships, as they dictate which types of resources (i.e., individual vs. group preference‐oriented and uncertainty‐reducing vs. not) are more likely to be valued, used, or effective in combating strain within a culture. Results revealed that societal individualism–collectivism and uncertainty avoidance independently moderated the relationships between certain job resources (i.e., job control, participation in decision making, and clear goals and performance feedback) and strain (i.e., job satisfaction and turnover intentions). This study expands our understanding of the cross‐cultural specificity versus generalizability of the job demands–resources model.