Theoretical Investigation of Reaction Pathways of 3-Methyloxadiazolinium Ion and 1,2,3-Oxadiazoline: Correlation with Experimental Findings

1994 ◽  
Vol 59 (12) ◽  
pp. 3301-3306 ◽  
Author(s):  
Marilyn B. Kroeger Koepke ◽  
Ann M. Schmiedekamp ◽  
Christopher J. Michejda
Keyword(s):  
Theoretical Investigation ◽  
Reaction Pathways ◽  
Experimental Findings

Intake-Air Oxygen-Enrichment of Diesel Engines as a Power Enhancement Method and Implications on Pollutant Emissions

2009 ◽  
Author(s):  
Theodoros C. Zannis ◽  
Dimitrios T. Hountalas ◽  
Elias A. Yfantis ◽  
Roussos G. Papagiannakis ◽  
Yiannis A. Levendis
Keyword(s):  
Theoretical Investigation ◽  
Diesel Engines ◽  
Equivalence Ratio ◽  
Combustion Efficiency ◽  
Oxygen Enrichment ◽  
Pollutant Emissions ◽  
Particulate Emissions ◽  
Engine Simulation ◽  
Hc Emissions ◽  
Experimental Findings

Increasing the in-cylinder oxygen availability of diesel engines is an effective method to improve combustion efficiency and to reduce particulate emissions. Past work on oxygen-enrichment of the intake air, revealed a large decrease of ignition delay, a remarkable decrease of soot emissions as well as reduction of CO and unburned hydrocarbon (HC) emissions while, brake specific fuel consumption (bsfc) remained unaffected or even improved. Moreover, experiments conducted in the past by authors revealed that oxygen-enrichment of the intake air (from 21% to 25% oxygen mole fraction) under high fuelling rates resulted to an increase of brake power output by 10%. However, a considerable increase of NOx emissions was recorded. This manuscript, presents the results of a theoretical investigation that examines the effect of oxygen enrichment of intake air, up to 30%v/v, on the local combustion characteristics, soot and NO concentrations under the following two in-cylinder mixing conditions: (1) lean in-cylinder average fuel/oxygen equivalence ratio (constant fuelling rate) and (2) constant in-cylinder average fuel/oxygen equivalence ratio (increased fuelling rate). A phenomenological engine simulation model is used to shed light into the influence of the oxygen content of combustion air on the distribution of combustion parameters, soot and nitric oxide inside the fuel jet, in all cases considered. Simulations were made for a naturally aspirated single-cylinder DI diesel engine “Lister LV1” at 2500 rpm and at various engine loads. The outcome of this theoretical investigation was contrasted with published experimental findings.

Permanganate oxidation of glycine: Kinetics, catalytic effects, and mechanisms

1987 ◽  
Vol 65 (10) ◽  
pp. 2329-2337 ◽  
Author(s):  
Joaquin F. Perez-Benito ◽  
Fernando Mata-Perez ◽  
Enrique Brillas
Keyword(s):  
Catalytic Reaction ◽  
Initial Reaction Rate ◽  
Reaction Pathways ◽  
Soluble Form ◽  
Initial Reaction ◽  
Order Unity ◽  
First Order ◽  
Constant Ph ◽  
Apparent Activation Energies ◽  
Experimental Findings

The oxidation of glycine by permanganate ion in aqueous phosphate buffers is autocatalyzed by the soluble form of colloidal manganese dioxide formed as a reaction product. Both the noncatalytic and the catalytic reaction pathways are first order in permanganate, the noncatalytic pathway is also first order in glycine, whereas the catalytic pathway has a kinetic order unity for the autocatalytic agent and a non-integral order (1.31) for glycine. Both reaction pathways are accelerated by an increase in the pH of the medium, whereas an increase in the buffer concentration at constant pH results in an increase in the rate of the noncatalytic pathway and a decrease in the rate of the catalytic one. Additions of potassium chloride to the solutions have no kinetic effect on the reaction. The apparent activation energies of the noncatalytic and catalytic reaction pathways are 64.5 and 62.0 kJ mol−1, respectively. On the other hand, manganese(II), thiosulfate, and hexacyanoferrate(II) ions, as well as benzyltriethylammonium chloride and arabic gum, have all been found to increase the initial reaction rate. Mechanisms in concordance with the experimental findings are proposed.

Theoretical investigation of conversion between different C2Hx species over Pd–Ag/Pd(100) surface alloys: influence on the selectivity and transformation of carbonaceous species

2018 ◽  
Vol 42 (24) ◽  
pp. 19827-19836 ◽  
Author(s):  
Qiang Li ◽  
Yucai Qin ◽  
Duping Tan ◽  
Yuan Xie ◽  
Manli Lv ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
Model Catalysts ◽  
Reaction Pathways ◽  
Surface Alloys ◽  
Acetylene Hydrogenation ◽  
Carbonaceous Species ◽  
Ethylene Selectivity

Full reaction pathways for acetylene hydrogenation on model catalysts are important for understanding the influence of ethylene selectivity and the formation of carbonaceous species.

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