Professor Frank Matthews Leslie FRS

FRSE Fellowship of the Royal Society of Edinburgh (FRSE) is an award granted to individuals that the Royal Society of Edinburgh, Scotland's national academy of science and letters, judged to be "eminently distinguished in their subject". This soci ...

(8 March 1935 – 15 June 2000) was a Scottish

mathematical physicist Mathematical physics refers to the development of mathematical methods for application to problems in physics. The ''Journal of Mathematical Physics'' defines the field as "the application of mathematics to problems in physics and the developmen ...

specializing in

continuum mechanics Continuum mechanics is a branch of mechanics that deals with the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles. The French mathematician Augustin-Louis Cauchy was the first to formulate such m ...

. He is remembered for the Ericksen–Leslie Theory which he developed with

Jerald Ericksen Jerald LaVerne Ericksen (December 20, 1924 – June 11, 2021) was an American mathematician specializing in continuum mechanics. Biography Ericksen was born in Portland, Oregon. His father Adolf worked at a Portland creamery and became adept a ...

to describe the

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

mesophase In chemistry and chemical physics, a mesophase is a state of matter intermediate between liquid and solid. Gelatin is a common example of a partially ordered structure in a mesophase. Further, biological structures such as the lipid bilayers of cel ...

s associated with

liquid crystal Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals. For example, a liquid crystal may flow like a liquid, but its molecules may be oriented in a crystal-like way. T ...

s. The parameters of this theory are viscosities called "Leslie coefficients", and the angle at which a (flow aligning) nematic orientates with respect to the direction of flow in a steady shear flow is called the "Leslie angle".

Life

Frank Leslie was born in

Dundee Dundee (; sco, Dundee; gd, Dùn Dè or ) is Scotland's fourth-largest city and the 51st-most-populous built-up area in the United Kingdom. The mid-year population estimate for 2016 was , giving Dundee a population density of 2,478/km2 or ...

on 8 March 1935, the son of William Oglivy Leslie and his wife Catherine Pitkethy Matthews. His maternal grandfather Frank Rollo Matthews (1860 to 1921) was a bibliophile, acquiring a considerable library that the family treasured. Frank Leslie attended

Harris Academy Harris Academy is a co-educational comprehensive school in the West End of Dundee, Scotland. Harris Academy was founded in 1885 and is the oldest state school in Dundee. Harris Academy is also one of the largest state run schools in Dundee in ...

and

University College, Dundee A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, t ...

where he was awarded the B.Sc. in 1957. With a scholarship from the legacy of

James Key Caird Sir James Key Caird, 1st Baronet (7 January 1837 – 9 March 1916) was a Scottish jute baron and mathematician. He was one of Dundee's most successful entrepreneurs, who used the latest technology in his Ashton and Craigie Mills. Caird was noted ...

, he entered the

University of Manchester , mottoeng = Knowledge, Wisdom, Humanity , established = 2004 – University of Manchester Predecessor institutions: 1956 – UMIST (as university college; university 1994) 1904 – Victoria University of Manchester 1880 – Victoria Univer ...

for graduate study. Leslie's gifts for communication were soon appreciated as he became assistant lecturer in 1959. The mathematics department at University of Manchester was led by

James Lighthill Sir Michael James Lighthill (23 January 1924 – 17 July 1998) was a British applied mathematician, known for his pioneering work in the field of aeroacoustics and for writing the Lighthill report on artificial intelligence. Biography J ...

who had pioneered an understanding of

thermosyphon Thermosiphon (or thermosyphon) is a method of passive heat exchange, based on natural convection, which circulates a fluid without the necessity of a mechanical pump. Thermosiphoning is used for circulation of liquids and volatile gases in heat ...

s. Leslie extended the work with his thesis "Problems of flow in the open thermosyphon and viscoelasticity of liquids" (1961). The external examiner was

James G. Oldroyd James Gardner Oldroyd (25 April 1921 – 22 November 1982''The Times'' November 25, 1982 page 26 "Deaths") was a British mathematician and noted rheologist. He formulated the Oldroyd-B model to describe the viscoelastic behaviour of non-Newtonia ...

, an authority on

viscoelasticity In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like water, resist shear flow and strain linearly wi ...

. As a post-doctoral student, Leslie continued his education at the

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...

. Being interested in

anisotropic Anisotropy () is the property of a material which allows it to change or assume different properties in different directions, as opposed to isotropy. It can be defined as a difference, when measured along different axes, in a material's physic ...

fluids, he wrote to Jerald Ericksen who was at

Johns Hopkins University Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private university, private research university in Baltimore, Maryland. Founded in 1876, Johns Hopkins is the oldest research university in the United States and in the western hem ...

. The collaboration with Ericksen grew from that time. A position at

Newcastle University Newcastle University (legally the University of Newcastle upon Tyne) is a UK public university, public research university based in Newcastle upon Tyne, North East England. It has overseas campuses in Singapore and Malaysia. The university is ...

provided the setting for Leslie to begin communicating his ideas. In December 1965 his important paper "Continuum theory of Liquid Crystals" appeared in

Proceedings of the Cambridge Philosophical Society ''Mathematical Proceedings of the Cambridge Philosophical Society'' is a mathematical journal published by Cambridge University Press for the Cambridge Philosophical Society. It aims to publish original research papers from a wide range of pure a ...

(60:949–55) in which he posited a "director" vector field characterizing an anisotropic fluid. In 1965 Leslie married Ellen Reoch; husband and wife crossed the Atlantic so Leslie and Ericksen could continue their collaboration at Johns Hopkins. Frank and Ellen had a daughter Sheena (born 1969) and a son Calum (born 1974). Frank and Ellen enjoyed playing

golf Golf is a club-and-ball sport in which players use various clubs to hit balls into a series of holes on a course in as few strokes as possible. Golf, unlike most ball games, cannot and does not use a standardized playing area, and coping wi ...

. Frank Leslie took up his permanent position at

Strathclyde University The University of Strathclyde ( gd, Oilthigh Shrath Chluaidh) is a public research university located in Glasgow, Scotland. Founded in 1796 as the Andersonian Institute, it is Glasgow's second-oldest university, having received its royal chart ...

in 1968, becoming a reader in 1971 and holding a personal chair from 1979 and an established chair from 1982. There he was able to host academic visitors such as Ericksen. As Chandrasekhar writes, "...the formulation of general conservation laws and constitutive equations describing the mechanical behaviour of the

nematic Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals. For example, a liquid crystal may flow like a liquid, but its molecules may be oriented in a crystal-like way. The ...

state is due to Ericksen and Leslie. Other continuum theories have been proposed, but it turns out that the Ericksen-Leslie approach is the one that is most widely used in discussing the nematic state." In the mid 1970s he consulted for

Defence Evaluation and Research Agency The Defence Evaluation and Research Agency (DERA) was a part of the UK Ministry of Defence (MoD) between 1995 and 2 July 2001. At the time it was the United Kingdom's largest science and technology organisation. It was regarded by its official hi ...

Malvern, Worcestershire Malvern is a spa town and civil parish in Worcestershire, England. It lies at the foot of the Malvern Hills, a designated Area of Outstanding Natural Beauty. The centre of Malvern, Great Malvern, is a historic conservation area, which grew dra ...

with

Cyril Hilsum Cyril Hilsum (born 17 May 1925) is a British physicist and academic. Hilsum was elected a member of the National Academy of Engineering in 1983 for the inventiveness and leadership in introducing III-V semiconductors into electronic technology ...

in support of British

LCD A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...

industries. Leslie demonstrated his commitment to

mathematics education In contemporary education, mathematics education, known in Europe as the didactics or pedagogy of mathematics – is the practice of teaching, learning and carrying out scholarly research into the transfer of mathematical knowledge. Although rese ...

by serving as

tutor TUTOR, also known as PLATO Author Language, is a programming language developed for use on the PLATO system at the University of Illinois at Urbana-Champaign beginning in roughly 1965. TUTOR was initially designed by Paul Tenczar for use in co ...

for 20 years for the

Open University The Open University (OU) is a British public research university and the largest university in the United Kingdom by number of students. The majority of the OU's undergraduate students are based in the United Kingdom and principally study off- ...

. He was

Justice of the Peace A justice of the peace (JP) is a judicial officer of a lower or ''puisne'' court, elected or appointed by means of a commission ( letters patent) to keep the peace. In past centuries the term commissioner of the peace was often used with the sa ...

(JP) for 15 years representing

Bearsden Bearsden () is a town in East Dunbartonshire, Scotland, on the northwestern fringe of Greater Glasgow. Approximately from Glasgow city centre, Glasgow City Centre, the town is effectively a suburb, and its housing development coincided with t ...

and

Milngavie Milngavie ( ; gd, Muileann-Ghaidh) is a town in East Dunbartonshire, Scotland and a suburb of Glasgow. It is on the Allander Water, at the northwestern edge of Greater Glasgow, and about from Glasgow city centre. It neighbours Bearsden. Milngav ...

. Leslie supported the

Scottish National Party The Scottish National Party (SNP; sco, Scots National Pairty, gd, Pàrtaidh Nàiseanta na h-Alba ) is a Scottish nationalist and social democratic political party in Scotland. The SNP supports and campaigns for Scottish independence from ...

and was treasurer of the party for 14 years. Further, in 1971 Leslie was elected

Elder An elder is someone with a degree of seniority or authority. Elder or elders may refer to: Positions Administrative * Elder (administrative title), a position of authority Cultural * North American Indigenous elder, a person who has and tr ...

in the

Church of Scotland The Church of Scotland ( sco, The Kirk o Scotland; gd, Eaglais na h-Alba) is the national church in Scotland. The Church of Scotland was principally shaped by John Knox, in the Scottish Reformation, Reformation of 1560, when it split from t ...

. He was elected a

Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...

in 1995. His proposers were

George Eason Prof George Eason FRSE FIMA (1930–1999) was a British mathematician who was Professor of Mathematics at Strathclyde University 1970 to 1983. He did work on the dynamical theory of elasticity. He wrote papers relating to mathematical solutions o ...

, Robin Knops,

Donald Pack Prof Donald Cecil Pack CBE FRSE FEIS FIMA (1920–2016) was a 20th-century British mathematician who worked on supersonic airflows. He was one of the persons responsible for Strathclyde University receiving its university status and was its V ...

, David Butler, John N. Sherwood and

Ian Sneddon Prof Ian Naismith Sneddon FRS FRSE FIMA OBE (8 December 1919 Glasgow, Scotland – 4 November 2000 Glasgow, Scotland) was a Scottish mathematician who worked on analysis and applied mathematics. Life Sneddon was born in Glasgow on 8 Dece ...

. Frank Leslie died 15 June 2000, of a

pulmonary embolism Pulmonary embolism (PE) is a blockage of an pulmonary artery, artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include dyspnea, shortness of breath, chest pain p ...

after a

hip replacement Hip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant, that is, a hip prosthesis. Hip replacement surgery can be performed as a total replacement or a hemi (half) replacement. Such joint replacement o ...

operation.

References

{{DEFAULTSORT:Leslie, Frank Matthews 1935 births 2000 deaths Scientists from Dundee Alumni of the University of Dundee Alumni of the University of Manchester Mathematical physicists Scottish mathematicians Rheologists Liquid crystals Massachusetts Institute of Technology alumni Academics of Newcastle University Academics of the University of Strathclyde Fellows of the Royal Society Elders of the Church of Scotland Scottish National Party politicians Deaths from pulmonary embolism 20th-century Scottish mathematicians People educated at Harris Academy