Benoît Paul Émile Clapeyron (; 26 January 1799 – 28 January 1864) was a French

engineer Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the limit ...

and

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

, one of the founders of

thermodynamics Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of th ...

Life

Born in

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), ma ...

, Clapeyron studied at the

École polytechnique École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing in région Île-de-France * École, Savoi ...

, graduating in 1818. Milton Kerker (1960
Sadi Carnot and the Steam Engine Engineers

Isis Isis (; ''Ēse''; ; Meroitic: ''Wos'' 'a''or ''Wusa''; Phoenician: 𐤀𐤎, romanized: ʾs) was a major goddess in ancient Egyptian religion whose worship spread throughout the Greco-Roman world. Isis was first mentioned in the Old Kin ...

51: 257–70 via JSTOR He also studied at

École des mines École may refer to: * an elementary school in the French educational stages normally followed by secondary education Secondary education or post-primary education covers two phases on the International Standard Classification of Education scal ...

. In 1820 he and

Gabriel Lamé Gabriel Lamé (22 July 1795 – 1 May 1870) was a French mathematician who contributed to the theory of partial differential equations by the use of curvilinear coordinates, and the mathematical theory of elasticity (for which linear elasticity ...

went to

Saint Petersburg Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), i ...

to teach and work at the school of public works there. He returned to Paris only after the Revolution of July 1830, supervising the construction of the first

railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

line connecting Paris to

Versailles The Palace of Versailles ( ; french: Château de Versailles ) is a former royal residence built by King Louis XIV located in Versailles, about west of Paris, France. The palace is owned by the French Republic and since 1995 has been managed, ...

and Saint-Germain. The half brothers Stéphane Mony and Eugène Flachat collaborated in this project, which was financed by Adolphe d'Eichthal^{( fr)},

Rothschild Rothschild () is a name derived from the German ''zum rothen Schild'' (with the old spelling "th"), meaning "with the red sign", in reference to the houses where these family members lived or had lived. At the time, houses were designated by sign ...

, Auguste Thurneyssen, Sanson Davillier and the

Péreire brothers Émile Pereire (3 December 1800, Bordeaux - 5 January 1875, Paris) and his brother Isaac Pereire (25 November 1806, Bordeaux – 12 July 1880, Gretz-Armainvilliers) were major figures in the development of France's finance and infrastructure durin ...

. Clapeyron took his steam engine designs to England in 1836 to find a manufacturer and engaged Sharp, Roberts and Co. From 1844 to 1859 Clapeyron was a professor at

École des Ponts et Chaussées École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing in région Île-de-France * École, Savoi ...

. Clapeyron married Mélanie Bazaine, daughter of Pierre-Dominique Bazaine (mathematician and ingénieur des ponts), and older sister of Pierre-Dominique (Adolphe) Bazaine (railway engineer) and Francois Achille Bazaine (Marshal of France).

Work

In 1834, he made his first contribution to the creation of modern thermodynamics by publishing a report entitled ''Mémoire sur la puissance motrice de la chaleur'' (''Memoir on the Motive Power of Heat''), in which he developed the work of the physicist Nicolas Léonard Sadi Carnot, deceased two years before. Though Carnot had developed a compelling analysis of a generalised

heat engine In thermodynamics and engineering, a heat engine is a system that converts heat to mechanical energy, which can then be used to do mechanical work. It does this by bringing a working substance from a higher state temperature to a lower state ...

, he had employed the clumsy and already unfashionable caloric theory. Clapeyron, in his memoire, presented Carnot's work in a more accessible and analytic graphical form, showing the

Carnot cycle A Carnot cycle is an ideal thermodynamic cycle proposed by French physicist Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s. By Carnot's theorem, it provides an upper limit on the efficiency of any classical thermodynam ...

as a closed

curve In mathematics, a curve (also called a curved line in older texts) is an object similar to a line, but that does not have to be straight. Intuitively, a curve may be thought of as the trace left by a moving point. This is the definition that ...

on an

indicator diagram An indicator diagram is a chart used to measure the thermal, or cylinder, performance of reciprocating steam and internal combustion engines and compressors. An indicator chart records the pressure in the cylinder versus the volume swept by the ...

, a chart of

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

against

volume Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). Th ...

(named in his honor Clapeyron's graph). Clapeyron's analysis of Carnot was more broadly disseminated in 1843 when

Johann Poggendorff Johann Christian Poggendorff (29 December 1796 – 24 January 1877), was a German physicist born in Hamburg. By far the greater and more important part of his work related to electricity and magnetism. Poggendorff is known for his electrostatic m ...

translated it into German. In 1842 Clapeyron published his findings on the "optimal position for the piston at which the various

valves A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...

should be opened or closed." In 1843, Clapeyron further developed the idea of a reversible process, already suggested by Carnot and made a definitive statement of ''Carnot's principle'', what is now known as the

second law of thermodynamics The second law of thermodynamics is a physical law based on universal experience concerning heat and energy interconversions. One simple statement of the law is that heat always moves from hotter objects to colder objects (or "downhill"), unles ...

. These foundations enabled him to make substantive extensions of Clausius' work, including the formula, now known as the Clausius–Clapeyron relation, which characterises the

phase transition In chemistry, thermodynamics, and other related fields, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states o ...

between two phases of

matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic part ...

. He further considered questions of phase transitions in what later became known as

Stefan problem In mathematics and its applications, particularly to phase transitions in matter, a Stefan problem is a particular kind of boundary value problem for a system of partial differential equations (PDE), in which the boundary between the phases can m ...

s. Clapeyron also worked on the characterisation of

perfect gas In physics and engineering, a perfect gas is a theoretical gas model that differs from real gases in specific ways that makes certain calculations easier to handle. In all perfect gas models, intermolecular forces are neglected. This means that one ...

es, the equilibrium of homogeneous

solid Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural ...

s, and calculations of the statics of continuous beams, notably the theorem of three moments (Clapeyron's

theorem In mathematics, a theorem is a statement that has been proved, or can be proved. The ''proof'' of a theorem is a logical argument that uses the inference rules of a deductive system to establish that the theorem is a logical consequence of t ...

Honors

*Member of the

Académie des Sciences The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at th ...

, (1858). *The

Rue Clapeyron ''Ruta graveolens'', commonly known as rue, common rue or herb-of-grace, is a species of ''Ruta'' grown as an ornamental plant and herb. It is native to the Balkan Peninsula. It is grown throughout the world in gardens, especially for its bluis ...

' 8th arrondissementbr>(here)
is named for him. *His name is one of the 72 names inscribed on the Eiffel Tower.

Publications

* *

References

External links

* {{DEFAULTSORT:Clapeyron, Benoit Paul Emile 1799 births 1864 deaths Scientists from Paris French physicists Thermodynamicists École Polytechnique alumni Mines ParisTech alumni Corps des mines Members of the French Academy of Sciences Corresponding members of the Saint Petersburg Academy of Sciences Fluid dynamicists