1,483 research outputs found
A Simplified Model to Predict Long-Term Ozone Concentrations in Europe
In the preparation process for the Second Sulphur Protocol of the Convention on Long-range Transboundary Air Pollution, integrated assessment models played an important role in identifying cost-effective strategies for reducing SO2 emissions in Europe. Applying this effect-based approach to other environmental problems (e.g., photo-oxidants) seems appealing. In view of the timetable adopted for the current preparation of an updated Protocol on emissions of nitrogen oxides, an integrated assessment tool for ozone is required in the very near future.
The paper presents an outline of an integrated assessment model for tropospheric ozone in Europe, with modules on emissions, emission control technologies and costs, ozone formation and environmental impacts. In its central part the paper focuses on the core element of such an approach, i.e., a concise description of the relationships between the precursor emissions (nitrogen oxides and volatile organic compounds) and regional ozone levels, which must be computationally efficient for use in an integrated assessment model.
Critical levels, i.e., threshold levels protecting vegetation from damage, have been recently established using long-term exposure measures. Consequently, to be suitable for integrated assessment models, source-receptor relationships should be able to describe the long-term changes of ozone, e.g., over a six-month period. Based on numerous scenario runs of the EMEP ozone model, polynomial source-receptor relationships have been statistically identified. Using national annual emissions of NO, and VOC, the model predicts regional responses of the six-month mean of early afternoon ozone concentrations. From this concentration measure, excess exposure as used in the definition of the critical levels can be derived. The paper introduces the methodology of the approach, evaluates the results and discusses areas of further work.
The suggested model formulation can be incorporated into the framework of an integrated assessment model, enabling (i) the assessment of costs and environmental benefits from alternative strategies to reduce precursor emissions and (ii) the identification of cost-optimized strategies to achieve environmental targets
Scenarios of cost-effective emission controls after 2020
Although emissions of most air pollutants are expected to significantly decline in the coming decades, the magnitude of the remaining impacts of poor air quality on human health and ecosystems will still be substantial. Technical and non-technical measures will be still available to reduce emissions and resulting impacts below the "current legislation" baseline levels.
However, these additional measures come at certain costs. It is estimated that full implementation of all available technical emission control measures would require up to 0.32% of GDP in 2030, and thereby increase total costs of air pollution control by more than 50%.
The GAINS optimization offers a tool for a systematic analysis of the cost-effectiveness of further measures. This report presents a series of illustrative optimization calculations addressing the health and ecosystems impact indicators that have been employed for earlier cost-effectiveness analyses for the 2005 Thematic Strategy on Air Pollution and the 2012 revision of the Gothenburg protocol.
As a first step, a series of calculations determined for each of these endpoints the increase in emission control costs for gradually tightened "gap closure" targets between the current legislation and the full application of all available technical measures. Costs increase most rapidly for improvements of health impacts (for ozone and PM), while significant progress at comparably low costs is possible for eutrophication and acidification.
In a second step, illustrative joint optimizations for multiple targets have been conducted, aiming at arbitrarily chosen gap closure targets of 25/50/75% for all impact indicators in 2030. The costs of the portfolios of measures that meet these targets range from Euros 0.3 bn/yr to Euros 9.9 bn/yr for the most ambitious case.
In a further step, the temporal interactions between emission reductions that have been optimized for a more distant year (e.g., 2030) and potential interim targets for earlier years are discussed. While there are several alternatives for securing temporal consistency of targets over time to avoid regret investments, the choice of the temporal path of environmental ambitions remains a political decision, depending on the weight given to environmental improvements in the near term versus the long-term target.
All calculations presented in this report must be considered as illustrative, since they do not yet include the forthcoming final TSAP baseline scenario that will build on the latest expectations of economic development and energy use
Players of Matching Pennies automatically imitate opponents’ gestures against strong incentives
There is a large body of evidence of apparently spontaneous mimicry in humans. This phenomenon has been described as "automatic imitation" and attributed to a mirror neuron system, but there is little direct evidence that it is involuntary rather than intentional. Cook et al. supplied the first such evidence in a unique strategic game design that gave all subjects a pecuniary incentive to avoid imitation [Cook R, Bird G, Lünser G, Huck S, Heyes C (2012) Proc Biol Sci 279(1729):780-786]. Subjects played Rock-Paper-Scissors repeatedly in matches between fixed pairs, sometimes with one and sometimes with both subjects blindfolded. The frequency of draws in the blind-blind condition was at chance, but in the blind-sighted condition it was significantly higher, suggesting automatic imitation had occurred. Automatic imitation would raise novel issues concerning how strategic interactions are modeled in game theory and social science; however, inferring automatic imitation requires significant incentives to avoid it, and subjects' incentives were less than 3 US cents per 60-game match. We replaced Cook et al.'s Rock-Paper-Scissors with a Matching Pennies game, which allows far stronger incentives to avoid imitation for some subjects, with equally strong incentives to imitate for others. Our results are important in providing evidence of automatic imitation against significant incentives. That some of our subjects had incentives to imitate also enables us clearly to distinguish intentional responding from automatic imitation, and we find evidence that both occur. Thus, our results strongly confirm the occurrence of automatic imitation, and illuminate the way that automatic and intentional processes interact in a strategic context
A spectroscopic cell for fast pressure jumps across the glass transition line
We present a new experimental protocol for the spectroscopic study of the
dynamics of glasses in the aging regime induced by sudden pressure jumps
(crunches) across the glass transition line. The sample, initially in the
liquid state, is suddenly brought in the glassy state, and therefore out of
equilibrium, in a four-window optical crunch cell which is able to perform
pressure jumps of 3 kbar in a time interval of ~10 ms. The main advantages of
this setup with respect to previous pressure-jump systems is that the pressure
jump is induced through a pressure transmitting fluid mechanically coupled to
the sample stage through a deformable membrane, thus avoiding any flow of the
sample itself in the pressure network and allowing to deal with highly viscous
materials. The dynamics of the sample during the aging regime is investigated
by Brillouin Light Scattering (BLS). For this purpose the crunch cell is used
in conjunction with a high resolution double monochromator equipped with a CCD
detector. This system is able to record a full spectrum of a typical glass
forming material in a single 1 s shot. As an example we present the study of
the evolution toward equilibrium of the infinite frequency longitudinal elastic
modulus (M_infinity) of a low molecular weight polymer (Poly(bisphenol
A-co-epichlorohydrin), glycidyl end capped). The observed time evolution of
M_infinity, well represented by a single stretched exponential, is interpreted
within the framework of the Tool-Narayanaswamy theory.Comment: 9 pages, 11 figure
Co-benefits of post-2012 global GHG-mitigation policies
This report provides an analysis of the impact of global greenhouse gas policies on traditional air pollutants using the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) model in the time horizon up to 2050. The integrated assessment framework of GAINS has been linked through an interface to the POLES global energy system model so that different global energy pathways can be implemented and examined. The impact analysis has been carried out based on projections of energy use data provided by the POLES model for two different climate policy scenarios, i.e., for a current policy Baseline scenario without any global greenhouse gas mitigation efforts, and a 2-degree Centigrade climate Mitigation scenario which assumes internationally coordinated action to mitigate climate change. Outcomes of the analysis are reported globally and for key world regions: EU-27, China, India and the US. The assessment takes into account current air pollution control legislation in each country.
The results of scenario calculations for SO2, NOx and PM2.5 emissions, air pollution control costs, as well as health and environmental impacts, indicate significant scope for co-benefits made possible through climate policies. Climate mitigation measures appear to be more effective in reducing oxides of sulphur and nitrogen, while emissions of particulate matter are reduced to a smaller extent. Decarbonisation of the global energy system by 2050 results in SO2 and NOx emissions lower by two-thirds than in the world without GHG-abatement efforts. Corresponding reduction in the emissions of PM2.5 is estimated at about 30% relative to the Baseline and is particularly sensitive to the assumptions on projected biomass combustion.
Expenditures on air pollution control under the global climate mitigation regime are reduced in 2050 by 250 billion Euros when compared to the Baseline scenario. Under the GAINS cost assumptions the largest potential for cost savings is reported for the transport sector, followed by savings in the power generation sector. Around one third of financial co-benefits estimated world-wide in this study by 2050 are allocated to China, while an annual cost saving of 35 billion Euros is estimated for the EU member countries if the current air pollution legislation and climate policies are adopted in parallel.
This study also quantifies health impacts of air pollution in Europe, China and India in terms of loss of life expectancy related to the exposure from anthropogenic emissions of PM2.5, as well as in terms of premature mortality due to ground-level ozone. For example in China, current ambient concentrations of PM2.5 are responsible for 38 months-losses in the average life expectancy. In 2050, the global GHG-mitigating strategies reduce this indicator in China by 16 months. In addition, decrease of ozone concentrations in the three regions as estimated for the climate Mitigation scenario in 2050 might save nearly 80,000 cases of premature death per year. Similarly significant are reductions of impacts on ecosystems due to acidification and eutrophication
Complimentary impact assessment on interactions between EU air quality policy and climate and energy policy
Through the looking glass: counter-mirror activation following incompatible sensorimotor learning.
The mirror system, comprising cortical areas that allow the actions of others to be represented in the observer's own motor system, is thought to be crucial for the development of social cognition in humans. Despite the importance of the human mirror system, little is known about its origins. We investigated the role of sensorimotor experience in the development of the mirror system. Functional magnetic resonance imaging was used to measure neural responses to observed hand and foot actions following one of two types of training. During training, participants in the Compatible (control) group made mirror responses to observed actions (hand responses were made to hand stimuli and foot responses to foot stimuli), whereas the Incompatible group made counter-mirror responses (hand to foot and foot to hand). Comparison of these groups revealed that, after training to respond in a counter-mirror fashion, the relative action observation properties of the mirror system were reversed; areas that showed greater responses to observation of hand actions in the Compatible group responded more strongly to observation of foot actions in the Incompatible group. These results suggest that, rather than being innate or the product of unimodal visual or motor experience, the mirror properties of the mirror system are acquired through sensorimotor learning
Non-equilibrium phase behavior and friction of confined molecular films under shear: a non-equilibrium molecular dynamics study
The phase behavior of a confined liquid at high pressure and shear rate, such as is found in elastohydrodynamic lubrication, can influence the traction characteristics in machine operation. Generic aspects of this behavior are investigated here using Non-equilibrium Molecular Dynamics (NEMD) simulations of confined Lennard-Jones (LJ) films under load with a recently proposed wall-driven shearing method without wall atom tethering [C. Gattinoni et al., Phys. Rev. E 90, 043302 (2014)]. The focus is on thick films in which the nonequilibrium phases formed in the confined region impact on the traction properties. The nonequilibrium phase and tribological diagrams are mapped out in detail as a function of load, wall sliding speed, and atomic scale surface roughness, which is shown can have a significant effect. The transition between these phases is typically not sharp as the external conditions are varied. The magnitude of the friction coefficient depends strongly on the nonequilibrium phase adopted by the confined region of molecules, and in general does not follow the classical friction relations between macroscopic bodies, e.g., the frictional force can decrease with increasing load in the Plug-Slip (PS) region of the phase diagram owing to structural changes induced in the confined film. The friction coefficient can be extremely low (∼0.01) in the PS region as a result of incommensurate alignment between a (100) face-centered cubic wall plane and reconstructed (111) layers of the confined region near the wall. It is possible to exploit hysteresis to retain low friction PS states well into the central localization high wall speed region of the phase diagram. Stick-slip behavior due to periodic in-plane melting of layers in the confined region and subsequent annealing is observed at low wall speeds and moderate external loads. At intermediate wall speeds and pressure values (at least) the friction coefficient decreases with increasing well depth of the LJ potential between the wall atoms, but increases when the attractive part of the potential between wall atoms and confined molecules is made larger
Revised Enskog Theory (RET) and molecular dynamics simulations of the viscosities and thermal conductivity of the hard sphere fluid and crystal
ACKNOWLEDGMENTS S.P would like to thank Prof. Andres Santos (Universidad de Extremadura, Badajoz) for helpful discussions and valuable suggestions. Some of the calculations were performed at the Poznan Supercomputing and Networking Center (PCSS).Peer reviewe
A comprehensive study of the thermal conductivity of the hard sphere fluid and solid by Molecular Dynamics simulation
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