Introduction

This review focuses on flames studies; the conditions in laboratory flames resemble those in combustors more closely than do the conditions in non-flame systems such as flow reactors, jet-stirred reactors and shock tubes. The most important difference, with respect to aromatics formation, is the breadth of the reactant pool. The non-flame systems usually contain a much smaller set of hydrocarbons; this makes them ideal for studying specific reaction pathways, but means that the relative importance of a group of competing pathways can differ from the case in flames.

Most laboratory flames can be classified as premixed or nonpremixed based on the mixing state of the reactants. In premixed flames, the fuel and oxidizer mix before the flame and approach the main reaction front together. In a nonpremixed flame, the fuel and oxidizer do not mix before the flame and they approach the main reaction front from opposite sides. Spark-ignition engines contain premixed flames because the fuel and air are perfectly mixed (in principle) with a flame front propagating through the mixture. Diesel engines contain nonpremixed flames because the fuel and air are not well-mixed and regions of evaporating fuel are surrounded by air with a flame front at the interface between the fuel vapor and air. Roughly speaking, premixed flames are easier to study, but nonpremixed flames more closely resemble the combustors where soot forms. This article reviews studies in both configurations; Section 2 discusses premixed flames and Section 3 discusses nonpremixed flames.

Lesson 9

Part 1

Gerund

The gerundis a very important grammatical peculiarity of scientific and technical texts. It is formed by adding the ending -ing to the verb: to read – read ing,

to paln - plann ing.

The features of the gerund:

1. the gerund as a verb:

a) can have a direct object: carrying out experiments -

проведение экспериментов;

b) is defined by an adverb: reading books aloud - чтение

книг вслух) can have both a simple form (doing) and a compound form (being done, having done, having been done);

2. the gerund as a noun:

a) possessive pronouns, prepositions and attributes can be before the gerund:

his reading - его чтение

for measuring - для измерения

my sister’s singing - пение моей сестры.