scholarly journals Algorithmic Analysis of Chemical Dynamics of the Autoignition of NH3–H2O2/Air Mixtures

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4422 ◽  
Author(s):  
Ahmed T. Khalil ◽  
Dimitris M. Manias ◽  
Efstathios-Al. Tingas ◽  
Dimitrios C. Kyritsis ◽  
Dimitris A. Goussis
Keyword(s):  
Singular Perturbation ◽  
Thermal Explosion ◽  
Time Scale ◽  
Ignition Delay ◽  
Initial Mixture ◽  
Time Frame ◽  
Computational Singular Perturbation ◽  
Algorithmic Analysis ◽  
The One ◽  
A Minor

The dynamics of a homogeneous adiabatic autoignition of an ammonia/air mixture at constant volume was studied, using the algorithmic tools of Computational Singular Perturbation. Since ammonia combustion is characterized by both unrealistically long ignition delays and elevated NO x emissions, the time frame of action of the modes that are responsible for ignition was analyzed by calculating the developing time scales throughout the process and by studying their possible relation to NO x emissions. The reactions that support or oppose the explosive time scale were identified, along with the variables that are related the most to the dynamics that drive the system to an explosion. It is shown that reaction H 2 O 2 (+M) → OH + OH (+M) is the one contributing the most to the time scale that characterizes ignition and that its reactant H 2 O 2 is the species related the most to this time scale. These findings suggested that addition of H 2 O 2 in the initial mixture will influence strongly the evolution of the process. It was shown that ignition of pure ammonia advanced as a slow thermal explosion with very limited chemical runaway. The ignition delay could be reduced by more than two orders of magnitude through H 2 O 2 addition, which causes only a minor increase in NO x emissions.

scholarly journals NO Formation and Autoignition Dynamics during Combustion of H2O-Diluted NH3/H2O2 Mixtures with Air

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 84
Author(s):  
Ahmed T. Khalil ◽  
Dimitris M. Manias ◽  
Dimitrios C. Kyritsis ◽  
Dimitris A. Goussis
Keyword(s):  
Water Vapor ◽  
Singular Perturbation ◽  
Chemical Reactions ◽  
Ignition Delay ◽  
Ternary Mixture ◽  
Oh Radicals ◽  
Nox Emissions ◽  
No Formation ◽  
Computational Singular Perturbation ◽  
H2o2 Addition

NO formation, which is one of the main disadvantages of ammonia combustion, was studied during the isochoric, adiabatic autoignition of ammonia/air mixtures using the algorithm of Computational Singular Perturbation (CSP). The chemical reactions supporting the action of the mode relating the most to NO were shown to be essentially the ones of the extended Zeldovich mechanism, thus indicating that NO formation is mainly thermal and not due to fuel-bound nitrogen. Because of this, addition of water vapor reduced NO formation, because of its action as a thermal buffer, but increased ignition delay, thus exacerbating the second important caveat of ammonia combustion, which is unrealistically long ignition delay. However, it was also shown that further addition of just 2% molar of H2O2 does not only reduce the ignition delay by a factor of 30, but also reverses the way water vapor affects ignition delay. Specifically, in the ternary mixture NH3/H2O/H2O2, addition of water vapor does not prolong but rather shortens ignition delay because it increases OH radicals. At the same time, the presence of H2O2 does not affect the influence of H2O in suppressing NO generation. In this manner, we were able to show that NH3/H2O/H2O2 mixtures offer a way to use ammonia as carbon-less fuel with acceptable NOx emissions and realistic ignition delay.

Use of Different Tissue Thromboplastins in the Control of Anticoagulant-Therapy

1958 ◽  
Vol 02 (05/06) ◽  
pp. 462-480 ◽  
Author(s):  
Marc Verstraete ◽  
Patricia A. Clark ◽  
Irving S. Wright
Keyword(s):  
Prothrombin Time ◽  
Anticoagulant Therapy ◽  
Factor Vii ◽  
Rabbit Brain ◽  
Minor Role ◽  
Rabbit Lung ◽  
Coagulation Mechanism ◽  
Time Test ◽  
The One ◽  
A Minor

SummaryAn analysis of the results of prothrombin time tests with different types of thromboplastins sheds some light on the problem why the administration of coumarin is difficult to standardize in different centers. Our present ideas on the subject, based on experimental data may be summarized as follows.Several factors of the clotting mechanism are influenced by coumarin derivatives. The action of some of these factors is by-passed in the 1-stage prothrombin time test. The decrease of the prothrombin and factor VII levels may be evaluated in the 1-stage prothrombin time determination (Quick-test). The prolongation of the prothrombin times are, however, predominantly due to the decrease of factor VII activity, the prothrombin content remaining around 50 per cent of normal during an adequate anticoagulant therapy. It is unlikely that this degree of depression of prothrombin is of major significance in interfering with the coagulation mechanism in the protection against thromboembolism. It may, however, play a minor role, which has yet to be evaluated quantitatively. An exact evaluation of factor VII is, therefore, important for the guidance of anticoagulant therapy and the method of choice is the one which is most sensitive to changes in factor VII concentration. The 1-stage prothrombin time test with a rabbit lung thromboplastin seems the most suitable method because rabbit brain preparations exhibit a factor VII-like activity that is not present in rabbit lung preparations.

THE ROLE OF ANTHROPONYMS IN THE SEMANTIC FIELD OF ARTISTIC WORKS

2019 ◽  
Vol 2019 (29) ◽  
pp. 66-77
Author(s):  
Lidiya Derbenyova
Keyword(s):  
Literary Work ◽  
Main Theme ◽  
Semantic Field ◽  
New Meanings ◽  
Minor Part ◽  
The One ◽  
A Minor ◽  
And Storage ◽  
Horizon Of Expectations

The article explores the role of antropoetonyms in the reader’s “horizon of expectation” formation. As a kind of “text in the text”, antropoetonyms are concentrating a large amount of information on a minor part of the text, reflecting the main theme of the work. As a “text” this class of poetonyms performs a number of functions: transmission and storage of information, generation of new meanings, the function of “cultural memory”, which explains the readers’ “horizon of expectations”. In analyzing the context of the literary work we should consider the function of antropoetonyms in vertical context (the link between artistic and other texts, and the groundwork system of culture), as well as in the context of the horizontal one (times’ connection realized in the communication chain from the word to the text; the author’s intention). In this aspect, the role of antropoetonyms in the structure of the literary text is extremely significant because antropoetonyms convey an associative nature, generating a complex mechanism of allusions. It’s an open fact that they always transmit information about the preceding text and suggest a double decoding. On the one hand, the recipient decodes this information, on the other – accepts this as a sort of hidden, “secret” sense.

The Green New Deal

2019 ◽  
Author(s):  
Robert C. Hockett
Keyword(s):  
New Deal ◽  
Large Scale ◽  
Public Investment ◽  
Climate Science ◽  
Time Frame ◽  
White Paper ◽  
Good News ◽  
Carbon Neutrality ◽  
The One ◽  
In Virtue Of

This white paper lays out the guiding vision behind the Green New Deal Resolution proposed to the U.S. Congress by Representative Alexandria Ocasio-Cortez and Senator Bill Markey in February of 2019. It explains the senses in which the Green New Deal is 'green' on the one hand, and a new 'New Deal' on the other hand. It also 'makes the case' for a shamelessly ambitious, not a low-ball or slow-walked, Green New Deal agenda. At the core of the paper's argument lies the observation that only a true national mobilization on the scale of those associated with the original New Deal and the Second World War will be up to the task of comprehensively revitalizing the nation's economy, justly growing our middle class, and expeditiously achieving carbon-neutrality within the twelve-year time-frame that climate science tells us we have before reaching an environmental 'tipping point.' But this is actually good news, the paper argues. For, paradoxically, an ambitious Green New Deal also will be the most 'affordable' Green New Deal, in virtue of the enormous productivity, widespread prosperity, and attendant public revenue benefits that large-scale public investment will bring. In effect, the Green New Deal will amount to that very transformative stimulus which the nation has awaited since the crash of 2008 and its debt-deflationary sequel.

Singular Perturbation Modeling of Nonlinear Processes with Non Explicit Time-Scale Separation

1996 ◽  
Vol 29 (1) ◽  
pp. 5799-5804 ◽  
Author(s):  
Aditya Kumar ◽  
Panagiotis D. Christofides ◽  
Prodromos Daoutidis
Keyword(s):  
Singular Perturbation ◽  
Time Scale ◽  
Nonlinear Processes ◽  
Scale Separation ◽  
Time Scale Separation

Politeness and social utopia in Friedrich Schiller’s Wilhelm Tell

2013 ◽  
Vol 3 (1) ◽  
pp. 34-55 ◽  
Author(s):  
Christel Björkstrand
Keyword(s):  
Common Ground ◽  
Initial Study ◽  
Minor Role ◽  
Politeness Theory ◽  
Dramatic Structure ◽  
German Philosopher ◽  
Social Visions ◽  
The One ◽  
A Minor ◽  
Social Utopia

This paper is an interdisciplinary analysis of Friedrich Schiller’s play Wilhelm Tell (1804). An initial study of its dramatic structure suggests a change in the relationship between the Swiss peasants and nobles. A further analysis, based on Brown’s and Levinson’s politeness theory confirms the development of a social utopia in the play, but also reveals that Wilhelm Tell plays a minor role in the social development described. The comparison of the play with earlier versions of the Tell legend highlights the roles of peasants and nobles in the establishment of the Swiss Confederation and suggests that Schiller elaborated extensively on the idea of a ‘common ground’ among the Swiss from different classes. The comparison between Schiller’s play and the contemporary German philosopher Johann Benjamin Erhard’s essay Über das Recht des Volks zu einer Revolution illustrates that Schiller’s social utopia develops in accordance with contemporary social visions. However, Tell’s act of murder separates him from the other Swiss protagonists in Schiller’s attempt to outline a righteous revolution, different from the one in France.

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