2063: Carnot Cycle

2018-10-24T21:39:01Z

Nystran:

{{comic
| number = 2063
| date = October 24, 2018
| title = Carnot Cycle
| image = carnot_cycle.png
| titletext = The Carnot cycle is more properly known by its full title, the "Carnot-Tolkien-Wagner Ring Cycle."
}}

==Explanation==
{{incomplete|Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}

This comic shows a {{w|Pressure–volume diagram}} which is used in this case for a {{w|Carnot cycle}}, a theoretical thermodynamic cycle and covers most thermodynamics classes which looks very much like the figure drawn. However in this case, [[Randall]] has replaced the labels of the 4 stages of the real Carnot cycle with new ones.

Pressure–volume diagrams were first developed to understand the efficiency of steam engines and plot the change of pressure ''P'' with respect to volume ''V'' for a specific process. The process forms a cycle and the amount of energy involved can be estimated by the area under the curve on the chart. The Carnot cycle describes the ideal efficiency that such an engine can achieve during the conversion of heat into work, or vice versa like in a refrigeration system. The real steps are called:
#'''Isothermal expansion'''
#'''Isentropic expansion'''
#'''Isothermal compression'''
#'''Isentropic compression'''
An isothermal process is a change of a system, in which the temperature remains constant but in this diagrams the volume increases (expansion) or decreases (compression). The term isentropic describes a lossless process where no matter or energy is transferred, here the increased volume only causes a further decrease in pressure.

Each step in this comic is explained below:

'''1. Isometric expansion.''' When heated, the gas becomes larger due to increasing volume

The comic text uses a circular argument. Additionally, "isometric" (equal dimensions) could mean that the gas does ''not'' change in volume, in contrast to the change in volume here.

'''2. Isotonic expansion.''' The gas expands further due to dark energy while percent milkfat remains constant.

{{w|Isotonic}} is a descriptor commonly associated with sports drinks (and not thermodynamics), which contain similar concentrations of salt and sugar as in the human body. {{w|Dark energy}} is hypothesized to be a cause for the expansion of the universe, which obviously isn't relevant to thermodynamics. The density of milk[https://hypertextbook.com/facts/2002/AliciaNoelleJones.shtml] depends on milkfat and solids-non-fat, which includes lactose. Fortified milk has increased solids-non-fat but the same percentage of milkfat, resulting in increased calories and an increased density. So the fortification of milk results in increased calories, possibly referred to as dark energy, and a contraction, as less space is needed for 1 kg of milk. However, this explanation does not match the expansion suggested in the comic.

'''3. Isopropyl compression.''' While inflation is held constant, the gas contracts due to tightening interest rates.

{{w|Isopropyl alcohol}} is commonly used for cleaning. Inflation and contraction could refer to changes in gas volume, but the reference to {{w|interest rate}}s puts them in the context of {{w|macroeconomics}}. Raising ("tightening") interest rates tends to reduce {{w|inflation}} and/or "contract" the economy. In economics (and other sciences) to better understand model parameter relations, some parameter may be held constant in theory. This could refer to the {{w|Fisher equation}}. Holding one parameter constant is also done in the Carnot cycle (for a physical parameter): not only in theory but also in practice! (In free market economies the inflation cannot be directly held constant).

'''4. Decline and fall.''' The gas diminishes and goes into the West while remaining Galadriel, completing the cycle.

{{w|Galadriel}} is a character in ''{{w|The Lord of the Rings}}''. She is one of the leading {{w|Elf (Middle-earth)|elves}}, a race that in the time of the book is said to be dwindling (in number and importance) in {{w|Middle Earth}} and migrating westward to {{w|Valinor}}. Galadriel is one of the last elves to leave, after successfully resisting temptation to take the One Ring and become an all-powerful queen who dominates Middle-earth, instead saying "I will diminish, and go into the West, and remain Galadriel." The title is a reference to {{w|Edward Gibbon}}'s 18th century masterpiece ''{{w|The History of the Decline and Fall of the Roman Empire}}''.

The title text refers to {{w|Richard Wagner}} and {{w|J.R.R Tolkien}}. Wagner's ''{{w|Der Ring des Nibelungen|Ring Cycle}}'' consists of four operas. Tolkien wrote ''{{w|The Lord of the Rings}}'', which some have [[wikipedia:J. R. R. Tolkien's influences#Wagnerian_influences|suggested]] was inspired by Wagner's Ring. Their works are known as {{w|literary cycle}}s.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[A cartesian plot in the first quadrant with axes labeled "P" on the y-axis and "V" on the x-axis, with a rhombus-shaped set of four points with arrows between them.]
:[Caption above the graph:]
:The four stages of the '''Carnot Cycle'''

:[The first line starts at the point at top left and goes right and slightly downwards to the next point. The label is:]
:'''1. Isometric expansion'''
:When heated, the gas becomes lager due to increasing volume

:[The next line starts at the last point and goes downwards, also still a little bit to the right.]
:'''2. Isotonic expansion'''
:The gas expands further due to dark energy while percent milkfat remains constant

:[The next line starts at this last point and to the left and slightly upwards.]
:'''3. Isopropyl compression'''
:While inflation is held constant, the gas contracts due to tightening interest rates

:[The last line goes upwards and slightly to the left, reaching the first point.]
:'''4. Decline and fall'''
:The gas diminishes and goes into the west while remaining Galadriel, completing the cycle

{{comic discussion}}

[[Category:Line graphs]]
[[Category:Physics]]
[[Category:LOTR]]

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2063: Carnot Cycle