Besoin d'aide pour comprendre le sujet dans sa globalité

Sujet du devoir

Bonjour, j'ai un texte d'anglais que je dois présenter d'une manire scientifique, est-il possible de m'aider à comprendre le corps du texte?

Je vous colle le texte, merci pour votre aide

DIESEL engines, with their rough-and-ready, spark-plug-free method of fuel 1 ignition, have a
2 reputation for being smoky and smelly. These days, that is a bit unfair. Fussy consumers and
3 even fussier regulations mean the sophisticated diesels used to propel modern cars are pretty
4 much as clean as their petrol-powered, sparked-up equivalents. But the heavy-duty diesels
5 employed in ships still have a long way to go.
6 And that matters. Research by James Corbett of the University of Delaware estimates that
7 soot from ships’ diesels contributes to 60,000 deaths from heart and lung disease every year.
8 Dirty ships’ diesels also produce oxides of nitrogen—the main ingredient of smog. Now that
9 land-based nitrogen-oxide pollution is being cleaned up, about 30% of the world’s remaining
10 emissions of the stuff are reckoned to come out of the funnels of seagoing cargo vessels.
11 The problem is incomplete combustion. The long-chain hydrocarbons used as diesel fuel do
12 not burn as easily as the lighter ones found in petrol. Some of the carbon therefore ends up as
13 soot, rather than carbon dioxide, and oxygen that should be combining with carbon combines
14 with nitrogen from the air instead.
15 But there may be a way out. Though it sounds bizarre, mixing water into the fuel helps it to
16 burn better. The heat of combustion breaks water molecules up. The resulting hydrogen atoms
17 help to split hydrocarbon molecules, making them more combustible, while the oxygen
18 released goes on to combine with the carbon, ensuring that more of it burns.
19 All this has, in truth, been known for years. But previous attempts to turn it into practical
20 technology have failed. Reinhard Strey of the University of Cologne is, however, having
21 another go. He thinks he has cracked the main (and obvious) difficulty—that oil and water do
22 not easily mix.
23 His answer is to use a surfactant. This is a molecule or molecular combination that has
24 different properties on different parts of its surface: in particular, one part prefers to dissolve
25 in water whereas another part prefers oil. Adding a surfactant to a mixture of oil and water
26 therefore binds the mixture together and allows it to form an emulsion of water droplets
27 dispersed in oil. (The dispersants being used against the Gulf of Mexico oil spill work
28 similarly, to create droplets of oil in water.)
29 That is effective, and has been tried in the past. But it is only part of the trick. Previous
30 attempts to mix water and diesel fuel this way have resulted in emulsions that still separate,
31 albeit more slowly than a surfactant-free mixture would. In practice, fuel can hang around in a
32 tank for a long time, so for the process to be useful, the emulsion has to be stable for ever.
33 Dr Strey was not put off by these previous failures. He searched for years and eventually
34 lighted on a mixture of oleic acid (a fatty acid found in various vegetable oils) and nitrogen35
containing compounds called amines. This mixture dissolves readily in diesel fuel and binds
36 water to it without any need for stirring. The water droplets themselves can be as small as a
37 nanometre (a billionth of a metre) across. That they are so small helps stabilise the emulsion.
2
The result is, in effect, a liquid sponge, and means the mixture can be stored 38 indefinitely, like
39 ordinary diesel, without risk of separation.
40 The result, when it is burned, is the near-complete abolition of soot, and a reduction of up to
41 80% in nitrogen-oxide emissions. The surfactant itself also burns without creating emissions
42 beyond water, carbon dioxide and nitrogen.
43 The next stage is to test the mixture in the real world. MTU, a German engine-builder, is now
44 looking into the matter. If all goes well, though, the days when a smoking funnel was an icon
45 of every child’s drawing of a ship on the horizon may be numbered.

Où j'en suis dans mon devoir

Dans l'ensemble, j'ai compris que nous parlions des effets du carburants sur les bateaux. Que pour préserver au mieux l'environnement, il fallait utiliser des surfactants qui sont des espèces possédant deux spécificités. Une est d'aimer l'eau et l'autre d'aimer les huiles

Après je ne comprends pas trop le texte dans son ensemble.