scholarly journals A Review of Chamber and Micrometeorological Methods to Quantify NH3 Emissions from Fertilisers Field Application

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Ester Scotto di Perta ◽  
Nunzio Fiorentino ◽  
Marco Carozzi ◽  
Elena Cervelli ◽  
Stefania Pindozzi
Keyword(s):  
State Of The Art ◽  
Direct Methods ◽  
Environmental Issues ◽  
Field Application ◽  
Emission Sources ◽  
Emission Inventories ◽  
Reliable Measurement ◽  
Building Characteristics ◽  
Common Effort ◽  
On Farm

Agriculture is mainly responsible for ammonia (NH3) volatilisation. A common effort to produce reliable quantifications, national emission inventories, and policies is needed to reduce health and environmental issues related to this emission. Sources of NH3 are locally distributed and mainly depend on farm building characteristics, management of excreta, and the field application of mineral fertilisers. To date, appropriate measurements related to the application of fertilisers to the field are still scarce in the literature. Proper quantification of NH3 must consider the nature of the fertiliser, the environmental variables that influence the dynamic of the emission, and a reliable measurement method. This paper presents the state of the art of the most commonly used direct methods to measure NH3 volatilisation following field application of fertilisers, mainly focusing on chamber method. The characteristics and the associated uncertainty of the measurement of the most widespread chamber types are discussed and compared to the micrometeorological methods.

scholarly journals Environmental issues and international relations, a new global (dis)order - the role of International Relations in promoting a concerted international system

2015 ◽  
Vol 58 (1) ◽  
pp. 191-209 ◽  
Author(s):  
Joana Castro Pereira
Keyword(s):  
International Relations ◽  
Natural Resources ◽  
State Of The Art ◽  
Positive Impact ◽  
International System ◽  
Global Environmental Change ◽  
Environmental Issues ◽  
Global Environmental ◽  
The Subject

Is it possible to talk about the rise of a new global (dis)order founded on the challenges posed by environmental issues? Through the review of the state of the art on the subject, this article analyzes the growing importance of the environment, and natural resources in particular, in international relations; and aims to raise awareness among International Relations scholars to the potential positive impact of the development of the discipline in integration with global environmental change studies.

scholarly journals Parallelization of the solve phase in a task-based Cholesky solver using a sequential task flow model

2019 ◽  
Vol 34 (3) ◽  
pp. 340-356
Author(s):  
Sébastien Cayrols ◽  
Iain S Duff ◽  
Florent Lopez
Keyword(s):  
Linear System ◽  
Flow Model ◽  
State Of The Art ◽  
Direct Methods ◽  
Dramatic Reduction ◽  
Multicore Architecture ◽  
Sequential Task ◽  
Sparse Linear System ◽  
Parallel Version ◽  
Two Phases

We describe the parallelization of the solve phase in the sparse Cholesky solver SpLLT when using a sequential task flow model. In the context of direct methods, the solution of a sparse linear system is achieved through three main phases: the analyse, the factorization and the solve phases. In the last two phases, which involve numerical computation, the factorization corresponds to the most computationally costly phase, and it is therefore crucial to parallelize this phase in order to reduce the time-to-solution on modern architectures. As a consequence, the solve phase is often not as optimized as the factorization in state-of-the-art solvers, and opportunities for parallelism are often not exploited in this phase. However, in some applications, the time spent in the solve phase is comparable to or even greater than the time for the factorization, and the user could dramatically benefit from a faster solve routine. This is the case, for example, for a conjugate gradient (CG) solver using a block Jacobi preconditioner. The diagonal blocks are factorized once only, but their factors are used to solve subsystems at each CG iteration. In this study, we design and implement a parallel version of a task-based solve routine for an OpenMP version of the SpLLT solver. We show that we can obtain good scalability on a multicore architecture enabling a dramatic reduction of the overall time-to-solution in some applications.

Review and comparison of high efficiency high power boost DC/DC converters for photovoltaic applications

2011 ◽  
Vol 59 (4) ◽  
pp. 499-506 ◽  
Author(s):  
J. Dawidziuk
Keyword(s):  
High Power ◽  
High Efficiency ◽  
State Of The Art ◽  
Environmental Issues ◽  
Switching Frequency ◽  
Power Losses ◽  
Renewable Energy Systems ◽  
Boost Converters ◽  
Power Mosfets ◽  
Photovoltaic Applications

Review and comparison of high efficiency high power boost DC/DC converters for photovoltaic applicationsRecent environmental issues have accelerated the use of more efficient and energy saving technologies in renewable energy systems. High power high efficiency boost DC/DC converters for the use in photovoltaic, fuel cell systems are discussed in this paper from the viewpoint of power losses and efficiency. State of the art converters with switching frequency within the range of 25 kHz with IGBTs to 100 kHz with power MOSFETs and the highest efficiency close to 98%, depending on the load conditions, is considered. A comparison and discussion of the highest efficiency high power DC/DC boost converters is also presented in this paper.

ELEMENTAL ANALYSIS OF ATMOSPHERIC AEROSOLS: RESULTS AND PERSPECTIVES OF THE PIXE TECHNIQUE

1990 ◽  
Vol 01 (02) ◽  
pp. 93-112 ◽  
Author(s):  
E. KOLTAY
Keyword(s):  
Elemental Analysis ◽  
Atmospheric Aerosols ◽  
Emission Sources ◽  
Emission Inventories ◽  
Aerosol Transport ◽  
Detailed Understanding ◽  
Main Research ◽  
Atmospheric Processes ◽  
Research Fields ◽  
Pixe Method

Information on the elemental constituents of atmospheric aerosols is of basic importance in studying atmospheric processes for a detailed understanding of the physics and chemistry of the atmosphere. Environmental pollution and its impact can be tested in the same way, too. In the present review we survey the main research fields in aerosol analytics that can be investigated with the application of the PIXE method. The nature of emission sources, emission inventories, aerosol transport and its tracing, arctic aerosols and climatic influences are mentioned along with methodological features of the present-day PIXE technique and its combined applications with other tools of instrumental analytics.

scholarly journals Better Prediction of Mutation Score

2021 ◽  
Author(s):  
Yossi Gil ◽  
Dor Ma’ayan
Keyword(s):  
Neural Networks ◽  
Real World ◽  
State Of The Art ◽  
Future Research ◽  
World Systems ◽  
Reliable Measurement ◽  
Mutation Score ◽  
Class Level ◽  
Effectiveness Prediction ◽  
Better Than

<div><div><div><p>Mutation score is widely accepted to be a reliable measurement for the effectiveness of software tests. Recent studies, however, show that mutation analysis is extremely costly and hard to use in practice. We present a novel direct prediction model of mutation score using neural networks. Relying solely on static code features that do not require generation of mutants or execution of the tests, we predict mutation score with an accuracy better than a quintile. When we include statement coverage as a feature, our accuracy rises to about a decile. Using a similar approach, we also improve the state-of-the-art results for binary test effectiveness prediction and introduce an intuitive, easy-to-calculate set of features superior to previously studied sets. We also publish the largest dataset of test-class level mutation score and static code features data to date, for future research. Finally, we discuss how our approach could be integrated into real-world systems, IDEs, CI tools, and testing frameworks.</p></div></div></div>

scholarly journals Using satellites to uncover large methane emissions from landfills

2021 ◽  
Author(s):  
Joannes Maasakkers ◽  
Daniel Varon ◽  
Aldís Elfarsdóttir ◽  
Jason McKeever ◽  
Dylan Jervis ◽  
...  
Keyword(s):  
High Resolution ◽  
Hot Spots ◽  
Buenos Aires ◽  
Methane Emissions ◽  
Emission Sources ◽  
Emission Inventories ◽  
Atmospheric Methane ◽  
Target Mode ◽  
Facility Level ◽  
Methane Concentrations

As atmospheric methane concentrations increase at record pace, it is critical to identify individual emission sources with high potential for mitigation. Landfills are responsible for large methane emissions that can be readily abated but have been sparsely observed. Here we leverage the synergy between satellite instruments with different spatiotemporal coverage and resolution to detect and quantify emissions from individual landfill facilities. We use the global surveying Tropospheric Monitoring Instrument (TROPOMI) to identify large emission hot spots, and then zoom in with high-resolution target-mode observations from the GHGSat instrument suite to identify the responsible facilities and characterize their emissions. Using this ‘tip and cue’ approach, we detect and analyze strongly emitting landfills (3-29 t hr−1) in Buenos Aires (Argentina), Delhi (India), Lahore (Pakistan), and Mumbai (India). We find that city-level emissions are 1.6-2.8 times larger than reported in commonly used emission inventories and that the landfills contribute 5-47% of those emissions. Our work demonstrates how complementary satellites enable global detection, identification, and monitoring of methane super-emitters at the facility-level.

scholarly journals Are contributions of emissions to ozone a matter of scale? – A study using MECO(n) (MESSy v2.50)

2019 ◽  
Author(s):  
Mariano Mertens ◽  
Astrid Kerkweg ◽  
Volker Grewe ◽  
Patrick Jöckel ◽  
Robert Sausen
Keyword(s):  
Source Apportionment ◽  
Emission Inventory ◽  
Climate Model ◽  
Ground Level ◽  
Emission Sources ◽  
Emission Inventories ◽  
Anthropogenic Emission ◽  
Model Resolution ◽  
Ground Level Ozone ◽  
Transport Emissions

Abstract. Anthropogenic and natural emissions influence the tropospheric ozone budget, thereby affecting air-quality and climate. To study the influence of different emission sources on the ozone budget, often source apportionment studies with a tagged tracer approach are performed. Studies investigating air quality issues usually rely on regional models with a high spatial resolution, while studies focusing on climate related questions often use coarsely resolved global models. It is well known that simulated ozone concentrations depend on the resolution of the model and the resolution of the emission inventory. Whether the contributions simulated by source apportionment approaches also depend on the model resolution, however, is still unclear. Therefore, this study is a first attempt to analyse the impact of the model, the model resolution, and the emission inventory resolution on simulated ozone contributions diagnosed with a tagging method. The differences of the ozone contributions caused by these factors are compared with differences which arise due to different emission inventories. To do so we apply the MECO(n) model system which on-line couples a global chemistry-climate model with a regional chemistry-climate model equipped with a tagging scheme for source apportionment. The results of the global model (300 km resolution) are compared with the results of the regional model at 50 km (Europe) and 12 km (Germany) resolution. Averaged over Europe the simulated contributions of land transport emissions to ground-level ozone differ by 10 % at maximum. For other anthropogenic emission sources the differences are in the same order of magnitude, while the contribution of stratospheric ozone to ground level ozone differs by up to 30 % on average. This suggests that ozone contributions of anthropogenic emission sources averaged on continental scale are rather robust with respect to different models, model and emission inventory resolutions. On regional scale, however, we quantified differences of the contribution of land transport emissions to ozone of up to 20 %. Depending on the region the largest differences are either caused by inter model differences, or differences of the anthropogenic emission inventories. Clearly, the results strongly depend on the compared models and emission inventories and cannot necessarily be generalised, however we show how the inclusion of source apportionment methods can help in analysing inter-model differences.

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