Ernst Theodor Amadeus Hoffmann (born Königsberg 24 January 1776; died Berlin 25 June 1822) was a German writer, composer, music critic, painter, caricaturist and lawyer. He liked the music of Wolfgang Amadeus Mozart so much that he changed his third name from Wilhelm to Amadeus. He is always known as E. T. A. Hoffmann. He was a man of many talents, but his greatest importance is as a Romantic writer. He wrote fantasy and horror stories which had a very large influence on German literature in the 19th century. His stories had a lot of influence in music. He is the hero of Jacques Offenbach's famous opera "The Tales of Hoffmann". His fantasies were used in other musical works such as Delibes’s ballet "Coppélia" and in operas by Busoni and Hindemith.
Hoffmann studied law at the University of Königsberg from where he graduated when he was only 16 years old. He finished his studies in Glogau and Berlin. His first job was in Posen. He married in 1802, but in the same year he had to leave his job because he had made fun of some people in his caricature drawings. He soon went to Warsaw where he worked as a lawyer as well as meeting famous writers. He composed music, including a symphony, a harp quintet and music for plays. Because of the political situation after the French invasion in 1806 he lost his job. He tried to get a job in Berlin but without success. In 1808 he went to Bamberg where he spent five years. His job there was as a conductor and theatre designer. He fell in love with a young girl called Julia Marc and composed sacred music and operas. He wrote musical criticism as well as stories for the newspaper "Allgemeine Musikalische Zeitung". These include the famous short stories "Ritter Gluck", "Don Juan" and the series called "Kreisleriana" ("Johannes Kreislers, des Kapellmeisters musikalische Leiden", i.e. "The musical suffering of the Director of Music Johannes Kreisler").
In 1813 he left Bamberg and spent some time in Dresden, Leipzig and, from 1814 onwards, Berlin. He was an excellent lawyer and was able to work very sensibly as a court official while, at the same time, spending some time devoted to art. He often met with literary friends to discuss literature and wrote more stories including "Die Lebensansichten des Katers Murr" ("Tom-cat Murr’s views on life"). His health started to become poor. He suffered from creeping paralysis. Once again he got into trouble because of his satire, but before his punishment could be sorted out he fell in and died.
Hoffmann wrote various kinds of stories. Some of them are about fate, e.g. "Elixiere des Teufels" which is about a Capuchin monk who is tempted by the drink offered by the devil. Some of them are fairy tales, e.g. "Der goldene Topf" ("The golden pan") and "Nussknacker und Mausekönig" ("Nutcracker and Mouse King"). Very often in these stories the supernatural meets everyday reality. Some of his stories are autobiographical because they fantasies about himself. In particular, the story about Kreisler became very popular and was used by musicians, e.g. Robert Schumann in his piano pieces called "Kreisleriana".
Hoffmann is one of the great writers of German prose. He brought his imaginary world to life with his Romantic characters.
Hydrogen atom
A hydrogen atom is an atom of the chemical element hydrogen.
Its parts are a single negatively-charged electron that circles a single positively-charged nucleus of the hydrogen atom. The nucleus of hydrogen consists of only a single proton (in the case of hydrogen-1 or "protium"), "or" it may also include one or more neutrons (giving deuterium, tritium, and other isotopes). The electron is bound to the nucleus by the Coulomb force. Hydrogen-1, also known as protium or "light hydrogen" is the main component of natural hydrogen.
Section 4.2 deals with the hydrogen atom specifically, but all of Chapter 4 is relevant.
Fuel cell
A fuel cell makes electricity using the energy released by mixing fuel with air, a reaction which creates water and sometimes also carbon dioxide. The most common fuel for fuel cells is hydrogen, which when reacted with oxygen from air produces only water. Fuel cells work like a battery being constantly fed with fuel so it never runs out (as long as you have enough fuel). Fuel cells are an important part of the hydrogen economy. Hydrogen molecules are found in substances such as methane, water and biomass but in all cases some energy is required to extract it. There are two common ways to produce hydrogen - it can be separated from most fuels like oil, gas, coal in a process called steam reforming, or it can be extracted from water using a process called electrolysis. If the hydrogen is separated from fossil fuels, carbon dioxide is released. If the energy used to extract it from water via electrolysis comes from solar or wind, then the hydrogen produced is benign because no emissions are released. Hydrogen can also be separated from renewable biogas, which means the carbon emitted is not of fossil origin and therefore is part of the natural carbon cycle.
Water is a molecule that consists of one oxygen atom and two hydrogen atoms. It takes energy to separate water into oxygen and hydrogen, and energy is released when they are put back together as water. A fuel cell puts hydrogen and oxygen back together in a way releases the energy in the form of electricity.
Fuel (the energy source, usually hydrogen) and air (which contains the oxygen) are put into opposite sides the fuel cell. In the middle of the fuel cell there is a "screen", called an electrolyte, sandwiched between two metal plates, called electrodes, which keeps the fuel and air separate. Different kinds of fuel cells get their names based on what type of screen is used to separate the fuel and air. The screen only allows specific charged molecules, also known as ions, to pass through them.
In order to create ions, electrons have to be carried from the one side of the system to the other. The electrons are split off from the fuel by the metal plate at the fuel side and need to travel to the air side to complete the reaction. Because the screen doesn't let electrons pass through, they go through a separate wire, to the other metal plate on the air side. The travel of electrons creates electric current (electricity). The wire is where electricity can be used. For example, the wire can be cut in half, and a light bulb can be connected in between the two halves.
In the meantime, the ions pass through the screen and react with the molecules (already on the other side) and electrons (which traveled through the wire, giving off energy to power electronics) on the other side. Water is formed (and, depending on the fuel type, occasionally other products), which them comes out through an exhaust pipe.
Fuel cells make electricity by combining oxygen and hydrogen. Efficiency is very good (about 40%-70%). They have a maximum efficiency of 83% if exhaust heat is used during the reaction. Also, fuel cells can use various fuels, for example, natural gas, methanol, LPG (Liquid Petroleum Gas), naphtha, kerosene etc.
Some types of fuel cells produce only water, which means no pollution. Most types of fuel cell cause much less emissions than classic ("caloric") power generation. They can consume the same fuel types as classic power generators, for example Diesel engines, but they are about two times as efficient, meaning they can produce the same amount of energy with half as much fuel, and thus at least half as much pollution. Additionally, the direct conversion fuel cells use has less risk of producing secondary emissions like NOx, SOx, and particulate matter, which are side effects of combustion, contribute to global warming, and are known as .
Fuel cells are very quiet. They have no moving parts aside from some fans to move air, and pumps to move water which means they very rarely require repairs, however some large fuel cells used for powering things like buildings can be quite fragile.